POWER SOURCE AND CONTROL SYSTEM FOR A LAWN MOWER
A battery-powered eclectic lawn mower includes battery packs mounted on a docking stations of a bus bar by way of a gravity-biased engagement. The lawn mower also includes a priority charging control logic for giving priority of charge to battery packs that have a state of charge over a threshold. The lawn mower also includes a live to drive system which alerts the user when the lawn mower is capable of moving in response to manipulation of controls. The lawn mower also includes a variable speed control which adjusts a sensitivity of speed controls such that more precise, slower speed control of the lawn mower is achieved when mowing around trees and the like.
The present invention relates to a lawn mower having a power source in the form of a plurality of battery packs secured within a battery compartment of the lawn mower. The present invention also relates to control systems of the lawn mower that controls a priority charging method of the power source, a live to drive control system that alerts the user of the lawn mower that the lawn mower is in an operable state, and a variable speed control system that controls the sensitivity of maneuvering controls of the lawn mower during operation.
SUMMARYIn one aspect, the invention provides an electric lawn mower comprising a frame; a drive wheel supporting the frame above a ground surface; a drive motor mounted to the frame and driving rotation of the drive wheel to move the lawn mower over the ground surface; an operator platform supported by the frame, and operable to support the weight of a user during operation of the lawn mower; a cutting deck coupled to the frame; a deck motor mounted to the cutting deck and configured to drive rotation of a blade under the cutting deck to cut grass under the cutting deck; a battery compartment supported by the frame and defining an inner space; a battery docking station mounted to a bottom wall of the battery compartment in the inner space; and a battery pack connected to the docking station through a gravity-biased connection, the battery pack providing electrical power to at least one of the drive motor and the deck motor.
In some embodiments, the electric lawn mower further comprises a lid for the battery compartment, the lid movable between an open position to provide access to the inner space and a closed position to restrict access to the inner space. In some embodiments, the lid includes a latch configured to selectively secure the lid in the closed position, and the lid, in the closed position, engages the battery pack to provide a gravity-assisted connection force that urges the battery packs into engagement with the battery docking station. In some embodiments, the battery pack weighs less than fifty-five pounds. In some embodiments, the docking station includes an alignment structure and an electrical connector, the alignment structure aligning the battery pack with the electrical connector prior to the battery pack engaging the electrical connectors as the battery pack is connected to the docking station. In some embodiments, the electric lawn mower further comprises a vehicle control module communicating with the drive motor and the deck motor to control operation of the drive motor and deck motor in response to commands from the user. In some embodiments, the electric lawn mower further comprises a user display, wherein the battery pack communicates with the user display to provide battery-related information on the user display. In some embodiments, the battery-related information includes state of charge of the battery pack. In some embodiments, the electric lawn mower further comprises left and right maneuvering controls graspable by the user on the operator platform, the electric lawn mower is a zero urn radius lawn mower; the drive wheel comprises left and right drive wheels; and the drive motor comprises left and right drive motors independently controlled by manipulation of the respective left and right maneuvering controls for independently driving rotation of the respective left and right drive wheels at a selected speed and direction of rotation. In some embodiments, the battery docking station comprises a plurality of battery docking stations mounted to a bottom wall of the battery compartment; and the battery pack comprises a plurality of battery packs connected to the battery docking stations. In some embodiments, the electric lawn mower further comprises a charging port communicating with the plurality of battery packs and a bus bar communicating with the plurality of docking stations, the charging port, and a vehicle control module, the vehicle control module receives power from the plurality of battery packs via the docking stations and the bus bar and directs the power to the drive motors and the deck motor. In some embodiments, a weight of the plurality of battery packs provides a gravity-biased connection between each of the plurality of battery packs and the plurality of docking stations such that the plurality of battery packs are removable from engagement with the plurality of docking stations without the need for tools. In some embodiments, each of the plurality of battery packs includes a handle integrally formed with an upper portion of the battery pack to facilitate handling of the battery pack by a user. In some embodiments, each of the plurality of docking stations includes contacts; each of the plurality of battery packs includes a flat bottom, a recessed portion, and contacts in the recessed portion; and contacts of the battery packs engage the contacts of the docking stations with a majority of the weight of the battery packs being borne by the flat bottom of the battery packs engaging a bottom of the battery compartment when the battery packs are lowered onto the docking stations. In some embodiment, the electric lawn mower further comprises a lid for the battery compartment; the lid is movable between an open position to provide access to the inner space and a closed position to restrict access to the inner space, the lid includes a latch configured to selectively secure the lid in the closed position, and the lid, in the closed position, engages the battery packs to provide a gravity-assisted connection force that overcomes a frictional force between the contacts of the battery packs and the contacts of the docking stations so the battery pack is electrically connected to the docking station.
In another aspect, the invention provides a method for managing a priority of charging among a plurality of battery packs in an electric vehicle or an electric device, the method comprising determining, by an electronic controller, a state of charge for each of the plurality battery packs; comparing, by the electronic controller, the state of charge of each of the plurality of battery packs to a predetermined threshold; grouping into a first set, by the electronic controller, any of the battery packs having a state of charge above the predetermined threshold; grouping into a second set, by the electronic controller, any of the battery packs having a state of charge under the predetermined threshold; and controlling, by the electronic controller, a charging configuration including at least a first charger to charge the first set before charging the second set.
In some embodiments, the method further comprises designating, by the electronic controller, a first battery pack of the battery packs as a master battery pack, and at least one other battery pack of the battery packs as slave battery pack. In some embodiments, each of the battery packs includes an identification number and wherein the step of designating one of the battery packs as a master battery pack includes designating the battery pack having the lowest identification number as the master battery pack. In some embodiments, the method further comprises in response to replacing one of the battery packs with a new battery pack having an identification number, the new battery pack and the non-replaced battery packs together defining a new plurality of battery packs: comparing the identification numbers of the new plurality of battery packs; and designating as the master battery pack the battery pack among the new plurality of battery packs having the lowest identification number. In some embodiments, comparing the state of charge of each of the plurality of battery packs to a predetermined threshold is performed with the predetermined threshold being 70%. In some embodiments, comparing the state of charge of each of the plurality of battery packs to a predetermined threshold is performed with the predetermined threshold being in the range 75% to 90%. In some embodiments, charging the first set includes charging the first set in order of battery state of charge from highest to lowest. In some embodiments, comparing the state of charge of each of the plurality of battery packs to a predetermined threshold is performed with the predetermined threshold being in the range 80% to 85%. In some embodiments, a first battery pack of the battery packs is a master battery pack, and wherein the electric vehicle includes a first charging port and a second charging port, the master battery pack communicating with both of the first charging port and the second charging port, the method further comprising: identifying whether the first charger of the charger configuration is connected to the first charging port and whether a second charger of the charger configuration is connected to the second charging portion; and determining a priority charging method based on whether one or both of the first charger and second charger are respectively connected to the first charging port and second charging port. In some embodiments, determining a priority charging method comprises, during the charging the first set step, charging a single battery pack in the event that only the first charger is connected to the first charging port and charging a plurality of battery packs in parallel in the event that both the first charger is connected to the first charging port and the second charger is connected to the second charging port. In some embodiments, the method further comprises grouping into a third set any of the battery packs having a state of charge under a low threshold and charging the battery packs in the third set concurrently. In some embodiments, the low threshold is 15%. In some embodiments, the method further comprises ordering the battery packs in the second set according to state of charge; wherein charging the second set comprises: charging the lowest state of charge battery in the second set; and once the state of charge of the lowest state of charge battery pack in the second set is equal to the state of charge of the second lowest state of charge battery pack in the second set, concurrently charging the lowest state of charge battery pack and the second lowest state of charge battery pack in the second set. In some embodiments, the electronic controller is at least one selected from the group consisting of a battery controller positioned within a master battery pack of the battery packs and a control of a vehicle control module positioned on the electric vehicle. In some embodiments, the electric vehicle is an electric lawn mower, the method further comprising: after charging the plurality of battery packs, discharging current from the plurality of battery packs to drive: a drive motor that drives rotation of a drive wheel to move the electric lawn mower over a ground surface, and a deck motor mounted to a cutting deck of the electric lawn mower that drives rotation of a blade under the cutting deck to cut grass under the cutting deck.
In another aspect, the invention provides a system for managing a priority of battery charging for an electric vehicle or an electric device, the system comprising: a frame; a battery compartment supported by the frame and defining an inner space: a plurality of battery docking stations in the inner space of the battery compartment; a plurality of battery packs, each battery pack of the plurality of battery packs connected to a respective docking station of the plurality of docking stations; and a charger configuration including at least a first charger and having a power input connector and a power output connector, the power input connector configured to receive power from an external source, the power output connector configured to provide charging current to the battery pack and an electronic controller coupled to the charging configuration and configured to: determine a state of charge for each of the plurality battery packs; compare the state of charge of each of the plurality of battery packs to a predetermined threshold; group into a first set any of the battery packs having a state of charge above the predetermined threshold; group into a second set any of the battery packs having a state of charge under the predetermined threshold; and control the charging configuration to charge the first set before charging the second set.
In some embodiments, each of the battery packs includes an identification number, the electronic controller is further configured to designate a first battery pack of the battery packs as a master battery pack in response to the first battery pack having the lowest identification number of the battery packs, and the electronic controller is further configured to designate at least one other battery pack of the battery packs as slave battery pack. In some embodiments, a first battery pack of the battery packs is a master battery pack, and wherein the electric vehicle includes a first charging port and a second charging port, the master battery pack communicating with both of the first charging port and the second charging port, the electronic controller is further configured to: identify whether the first charger of the charger configuration is connected to the first charging port and whether a second charger of the charger configuration is connected to the second charging portion; and determine a priority charging method based on whether one or both of the first charger and second charger are respectively connected to the first charging port and second charging port. In some embodiments, the electronic controller is further configured to order the battery packs in the second set according to state of charge, and to control the charging configuration to charge the second set, the electronic controller is further configured to: charge the lowest state of charge battery in the second set; and once the state of charge of the lowest state of charge battery pack in the second set is equal to the state of charge of the second lowest state of charge battery pack in the second set, concurrently charge the lowest state of charge battery pack and the second lowest state of charge battery pack in the second set. In some embodiment, the electronic controller is at least one selected from the group consisting of a battery controller positioned within a master battery pack of the battery packs and a control of a vehicle control module positioned on the electric vehicle.
In another aspect, the invention provides a method for alerting a user of an electric vehicle that the vehicle is in a live to drive state, the electric vehicle including at least one maneuvering control, the method comprising: determining with a vehicle control module that a set of predetermined conditions of the live to drive state are satisfied; generating an audible alert with an audible element in response to identifying that the set of predetermined conditions of the live to drive state are satisfied; generating a visual alert at a user display on the vehicle in response to identifying that the set of predetermined conditions of the live to drive state are satisfied, and identifying that the electric vehicle is in the live to drive state based on determining that the set of predetermined conditions of the live to drive state are satisfied, wherein, in the live to drive state, the vehicle can be moved by operation of the maneuvering control.
In some embodiments, the audible element includes at least one from the group of: a speaker supported by the lawn mower and a headset used by the user. In some embodiments, the audible element includes a headset; and generating an audible alert includes transmitting the audible alert via a short-range wireless communication protocol or a wired connection between the headset and the vehicle control module. In some embodiments, generating a visual alert includes at least one from the group of: illuminating an LED, flashing an LED, and displaying a message on a screen visible to the user. In some embodiments, the method further comprises determining operational states of the vehicle with a plurality of sensors monitoring a system interface, the maneuvering control, an operator platform supporting the user, and the power source providing motive power for the vehicle; and wherein identifying that the predetermined conditions of the live to drive state satisfied includes interpreting whether the operational states of the vehicle meets the set of predetermined conditions. In some embodiments, the predetermined conditions includes at least one from the group of: a battery charger is disconnected from the power source, a pre-charge of the power source is complete, the user is seated in a seat on the operator platform, a parking brake is applied, the maneuvering controls are in a neutral position, there are no system faults, and an ignition is in an on position. In some embodiments, the method further comprises generating an error alert and not permitting the vehicle to operate when the set of predetermined conditions indicative of the live to drive state are not met by the operational states. In some embodiments, generating an audible alert comprises generating a first audible alert, the method further comprising generating a second audible alert one second following the first audible alert. In some embodiments, a parking brake is disabled following the second audible alert so the vehicle can be moved by operation of the at least one maneuvering control.
In another aspect, the invention provides an electric vehicle including a system for alerting a user of the electric vehicle that the vehicle is in a live to drive state, the electric vehicle comprising: frame; a drive wheel supporting the frame above a ground surface; a drive motor mounted to the frame and driving rotation of the drive wheel to move the electric vehicle over the ground surface; an audible element configured to generate sound; a user display; at least one maneuvering control configured to: indicate a drive command for the drive motor; an electronic controller coupled to the at least one maneuvering control and the drive motor, the electronic controller configured to determine that a set of predetermined conditions of the live to drive state are satisfied; generate an audible alert with the audible element in response to determining that the set of predetermined conditions of the live to drive state are satisfied; generate a visual alert at the user display on the vehicle in response to determining that the set of predetermined conditions of the live to drive state are satisfied, and identify the vehicle is in the live to drive state based on determining that the set of predetermined conditions of the live to drive state are satisfied, wherein, in the live to drive state, the vehicle can be moved by operation of the at least one maneuvering control.
In some embodiments, the audible element includes at least one from the group of: a speaker supported by the electric vehicle and a headset used by the user. In some embodiments, the audible element includes a headset; and to generate the audible alert, the electronic controller is configured to transmit the audible alert via a short-range wireless communication protocol or a wired connection to the headset. In some embodiments, to generate a visual alert, the electronic controller is configured to at least one from the group of: illuminate an LED, flash an LED, and display a message on a screen visible to the user. In some embodiments, the electronic controller is further configured to determine operational states of the vehicle with a plurality of sensors monitoring a system interface, the at least one maneuvering control, an operator platform supporting the user, and a power source providing motive power for the vehicle; and wherein, to identify that the vehicle is in the set of preconditions of the live to drive state are satisfied, the electronic controller is further configured to interpret whether the operational states of the vehicle meets the set of predetermined conditions. In some embodiments, the predetermined conditions includes at least one from the group of: a battery charger is disconnected from the power source, a pre-charge of the power source is complete, the user is seated in a seat on the operator platform, a parking brake is applied, the at least one maneuvering control is in a neutral position, there are no system faults, and an ignition is in an on position. In some embodiments, the electronic controller is further configured to generate an error alert and not permit the vehicle to operate when the set of predetermined conditions indicative of the live to drive state is not met by the operational states. In some embodiments, the audible alert is a first audible alert, and the electronic controller is further configured to generate a second audible alert one second following the first audible alert. In some embodiments, the electric vehicle further comprises a parking brake configured to restrict movement of the electric vehicle, wherein the parking brake is configured to be disabled following the second audible alert so the vehicle can be moved by operation of the at least one maneuvering control.
In another aspect, the invention provides a variable speed control system for a lawn mower, the lawn mower including an operator zone comprising an area accessible by a user of the lawn mower during operation of the lawn mower, the system comprising: a maneuvering control in the operator zone and movable by the user through a fill range of motion including a maximum speed end at which the lawn mower moves at a maximum speed: and an adjustment mechanism in the operator zone and manually adjustable by the user, the adjustment mechanism adjusting the maximum speed.
In some embodiments the adjustment mechanism comprises an analog mechanism. In some embodiments, the adjustment mechanism is movable between a plurality of positions to allow the maximum speed to be variably adjusted. In some embodiments, the adjustment mechanism is movable between three positions corresponding to three different speed modes corresponding to a low maximum speed, a standard maximum speed, and a high maximum speed. In some embodiments, the adjustment mechanism is movable between discrete positions, the system further comprising a detent mechanism for holding the adjustment mechanism in at least one of the discrete positions. In some embodiments, the adjustment mechanism is integrated within the maneuvering control such that the adjustment mechanism can be manipulated by the user without removing the user's hands from the maneuvering control. In some embodiments, the maximum speed varies as a linear function of the position of the adjustment mechanism. In some embodiments, the system further comprises a vehicle control module communicating with the maneuvering control to adjust a sensitivity of the maneuvering control in response to a position of the adjustment mechanism. In some embodiments, the vehicle control module communicates with a user display in the operator zone to provide a visual alert to the user relating to the adjusted maximum speed. In some embodiments, the visual alert is a bar or dial corresponding to a position of the adjustment mechanism. In some embodiments, the maneuvering control comprises left and right control arms operably coupled to left and right drive wheels of the lawn mower to enable the user to independently control the speed and direction of the left and right drive wheels by moving the left and right control arms through the range of motion.
In another aspect, the invention provides an electric lawn mower, the electric lawn mower comprising a frame; a drive wheel supporting the frame above a ground surface; a cutting deck coupled to the frame; a drive motor mounted to the frame and driving rotation of the drive wheel to move the electric lawn mower over the ground surface, and a deck motor mounted to the cutting deck and configured to drive rotation of a blade under the cutting deck to cut grass under the cutting deck: a plurality of battery packs supported by the frame and configured to provide electrical power to the drive motor and to the deck motor; an electronic controller coupled to the drive motor and to the deck motor, the electronic controller configured to: determine a maximum steady state current value for the plurality of battery packs; determine a maximum drive current value for the drive motor and a maximum deck current value for the deck motor based on the maximum steady state current value, a duty cycle of the drive motor, and a duty cycle of the deck motor; control the drive motor to maintain a motor current of the drive motor below the maximum drive current value; and control the deck motor to maintain a motor current of the deck motor below the maximum deck current value.
In some embodiment, the drive motor is a first drive motor of a plurality of drive motors mounted to the frame and the drive wheel is a first drive wheel of a plurality of drive wheels supporting the frame above a ground surface, each drive motor of the plurality of drive motors is associated with a respective drive wheel of the plurality of drive wheels to move the electric lawn mower over the ground surface, the deck motor is a first deck motor of a plurality of deck motors, and the blade is a first blade of a plurality of blades under the cutting deck, and each deck motor of the plurality of deck motors is configured to drive rotation of a respective blade of the plurality of blades to cut grass under the cutting deck. In some embodiments, to determine a maximum drive current value for the drive motor and a maximum deck current value for the deck motor based on the maximum steady state current value, a duty cycle of the drive motor, and a duty cycle of the deck motor, the motor is further configured to: calculate a maximum aggregate drive motor current for the plurality of drive motors and a maximum aggregate deck motor current for the plurality of deck motors based on the maximum steady state current value, a duty cycle of the drive motor, and a duty cycle of the deck motor, divide the maximum aggregate drive motor current by a total number of the plurality of drive motors to determine the maximum drive current value, and divide the maximum aggregate deck motor current by a total number of the plurality of deck motors to determine the maximum deck current value. In some embodiments, the electronic controller includes a vehicle control module including a processor and memory, a drive controller for each of the plurality of drive motors, and a deck controller for each of the plurality of deck controllers, the vehicle control module is configured to determine and provide the maximum drive current value to each of the plurality of drive controllers and is configured to determine and provide the maximum deck current value to each of the plurality of deck controllers. In some embodiment, each of the plurality of drive controllers is configured to control an associated drive motor to maintain motor current of the associated drive motor below the maximum drive current value, and each of the plurality of deck controllers is configured to control an associated deck motor to maintain motor current of the associated deck motor below the maximum drive current value. In some embodiments, the plurality of battery packs include a master battery pack and a plurality of slave battery packs, and the master battery pack is configured to: determine a steady state current value for each of the plurality of battery packs, sum the steady state current values for each of the plurality of battery packs, and provide, to the electronic controller, the sum of the steady state current values as the maximum steady state current value. In some embodiments, each battery pack of the plurality of battery packs includes a plurality of battery cells, a temperature sensor, cell group voltage sensors, a pack voltage sensor, and a battery controller coupled to the temperature sensor and the voltage sensors, and wherein the battery controller of each of the plurality of battery packs is configured to calculate the steady state current value of the respective battery pack of which the battery controller is a part based on: a minimum cell voltage measured by the cell group voltage sensors of the respective battery pack, a pack state of charge determined from the pack voltage sensor of the respective battery pack, and an internal pack temperature from the temperature sensor of the respective battery pack. In some embodiments, the battery controller of each of the plurality of battery packs is further configured to reduce the steady state current value of the respective battery pack of which the battery controller is a part based on one or more of the following: the minimum cell voltage of the respective battery pack being below a voltage threshold, the pack state of charge of the respective battery pack being below a charge threshold, and the internal pack temperature of the respective battery pack being above a temperature threshold. In some embodiments, the battery controller of each of the plurality of battery packs is further configured to increase the steady state current value of the respective battery pack of which the battery controller is a part based on one or more of the following: the minimum cell voltage of the respective battery pack being above a voltage threshold, the pack state of charge of the respective battery pack being above a charge threshold, and the internal pack temperature of the respective battery pack being below a temperature threshold. In some embodiments, the electronic controller is further configured to: control the drive motor to maintain a regenerative current from the drive motor below a maximum drive charge current value; and control the deck motor to maintain a regenerative current from the deck motor below a maximum deck charge current value.
In another aspect, the invention provides a method of controlling power distribution in an electric lawn mower, the method comprising: determining, by an electronic controller, a maximum steady state current value for a plurality of battery packs supported by a frame of the electric lawn mower and configured to provide electrical power to a drive motor and to a deck motor, where the drive motor is mounted to the frame and configured to drive rotation of a drive wheel to move the electric lawn mower over a ground surface and where the deck motor is configured to drive rotation of a blade to cut grass under a cutting deck: determining, by the electronic controller, a maximum drive current value for the drive motor and a maximum deck current value for the deck motor based on the maximum steady state current value, a duty cycle of the drive motor, and a duty cycle of the deck motor; controlling, by the electronic controller, the drive motor to maintain a motor current of the drive motor below the maximum drive current value; and controlling, by the electronic controller, the deck motor to maintain a motor current of the deck motor below the maximum deck current value.
In some embodiments, the drive motor is a first drive motor of a plurality of drive motors mounted to the frame and the drive wheel is a first drive wheel of a plurality of drive wheels supporting the frame above a ground surface, and wherein the deck motor is a first deck motor of a plurality of deck motors, and the blade is a first blade of a plurality of blades under the cutting deck, the method further comprising driving, by each drive motor of the plurality of drive motors, a respective drive wheel of the plurality of drive wheels to move the electric lawn mower over the ground surface, and driving, by each deck motor of the plurality of deck motors, a respective blade of the plurality of blades to cut grass under the cutting deck. In some embodiments, determining a maximum drive current value for the drive motor and a maximum deck current value for the deck motor based on the maximum steady state current value, the duty cycle of the drive motor, and the duty cycle of the deck motor includes: calculating a maximum aggregate drive motor current for the plurality of drive motors and a maximum aggregate deck motor current for the plurality of deck motors based on the maximum steady state current value, a duty cycle of the chive motor, and a duty cycle of the deck motor, dividing the maximum aggregate drive motor current by a total number of the plurality of drive motors to determine the maximum drive current value, and dividing the maximum aggregate deck motor current by a total number of the plurality of deck motors to determine the maximum deck current value. In some embodiments, the electronic controller includes a vehicle control module including a processor and memory, a drive controller for each of the plurality of drive motors, and a deck controller for each of the plurality of deck controllers, the method further comprising:
providing, by the vehicle control module, the maximum drive current value to each of the plurality of drive controllers; and providing, by the vehicle control module, the maximum deck current value to each of the plurality of deck controllers. In some embodiments, controlling, by each of the plurality of drive controllers, an associated drive motor to maintain motor current of the associated drive motor below the maximum drive current value, and controlling, by each of the plurality of deck controllers, an associated deck motor to maintain motor current of the associated deck motor below the maximum drive current value. In some embodiments, the plurality of battery packs include a master battery pack and a plurality of slave battery packs, the method further comprising: determining, by the master battery pack, a steady state current value for each of the plurality of battery packs, summing, by the master battery pack, the steady state current values for each of the plurality of battery packs, and providing, by the master battery pack, the sum of the steady state current values as the maximum steady state current value to the electronic controller. In some embodiments, each battery pack of the plurality of battery packs includes a plurality of battery cells, a temperature sensor, cell group voltage sensors, a pack voltage sensor, and a battery controller coupled to the temperature sensor and the voltage sensors, the method further comprising: calculating, by the battery controller of each of the plurality of battery packs, the steady state current value of the respective battery pack of which the battery controller is a part based on: a minimum cell voltage measured by the cell group voltage sensors of the respective battery pack, a pack state of charge determined from the pack voltage sensor of the respective battery pack, and an internal pack temperature from the temperature sensor of the respective battery pack. In some embodiments, the method further comprises reducing, by the battery controller of each of the plurality of battery packs, the steady state current value of the respective battery pack of which the battery controller is a part based on one or more of the following: the minimum cell voltage of the respective battery pack being below a voltage threshold, the pack state of charge of the respective battery pack being below a charge threshold, and the internal pack temperature of the respective battery pack being above a temperature threshold. In some embodiments, the methods further comprises increasing, by the battery controller of each of the plurality of battery packs, the steady state current value of the respective battery pack of which the battery controller is a part based on one or more of the following: the minimum cell voltage of the respective battery pack being above a voltage threshold, the pack state of charge of the respective battery pack being above a charge threshold, and the internal pack temperature of the respective battery pack being below a temperature threshold. In some embodiments, the method further comprises controlling, by the electronic controller, the drive motor to maintain a regenerative current from the drive motor below a maximum drive charge current value; and controlling, by the electronic controller, the deck motor to maintain a regenerative current from the deck motor below a maximum deck charge current value.
In another aspect, the invention provides an electric lawn mower, the electric lawn mower comprising: a frame; a drive wheel supporting the frame above a ground surface; a drive motor mounted to the frame and driving rotation of the drive wheel to move the electric lawn mower over the ground surface; a maneuvering control configured to indicate a desired motor control for the drive motor; a motor speed sensor configured to sense a rotational speed of the drive motor; and an electronic controller coupled to the drive motor, the electronic controller configured to: determine a desired motor speed based on an output from the maneuvering control; determine a sensed motor speed based on an output of the motor speed sensor; determine a proportional term adjustment factor based on the sensed motor speed; and control the drive motor according to a proportional integral drive control loop having a proportional term and an integral term, wherein the proportional term is determined based on a difference between the desired motor speed and the sensed motor speed and based on the proportional term adjustment factor.
In some embodiments, the electric lawn mower further comprises a second drive wheel supporting the frame above the ground surface; a second drive motor mounted to the frame and driving rotation of the second drive wheel to move the electric lawn mower over the ground surface; a second maneuvering control configured to indicate a desired motor control for the second drive motor; and a second motor speed sensor configured to sense a rotational speed of the second drive motor; wherein the electronic controller is further coupled to the second drive motor and configured to: determine a desired motor speed for the second drive motor based on an output from the second maneuvering control; determine a sensed motor speed of the second drive motor based on an output of the motor speed sensor; determine a second proportional term adjustment factor based on the sensed motor speed of the second drive motor; and control the second drive motor according to a second proportional integral drive control loop having a second proportional term and a second integral term, wherein the second proportional term is determined based on a difference between the desired motor speed for the second drive motor and the sensed motor speed of the second drive motor and based on the second proportional term adjustment factor. In some embodiments, the electric lawn mower further comprises an operator platform supported by the frame, and operable to support the weight of a user during operation of the lawn mower; a cutting deck coupled to the frame; a deck motor mounted to the cutting deck and configured to drive rotation of a blade under the cutting deck to cut grass under the cutting deck; a battery compartment supported by the frame and defining an inner space; a battery docking station mounted to a bottom wall of the battery compartment in the inner space; and a battery pack connected to the docking station, the battery providing electrical power to at least one of the drive motor and the deck motor. In some embodiments, to control the drive motor according to the proportional integral drive control loop, the electronic controller is further configured to: determine an integral term based on differences between desired motor speeds and sensed motor speeds over time; sum the integral term and the proportional term to generate a motor control signal for the drive motor; and control the drive motor based on the motor control signal. In some embodiments, the drive motor is a brushless motor and the motor control signal is a pulse width modulated (PMW) signal. In some embodiments, to determine the proportional term, the electronic controller is further configured to multiply the difference between the desired motor speed and the sensed motor speed by the proportional term adjustment factor. In some embodiments, the proportional term adjustment factor increases as the sensed motor speed of the drive motor decreases and decreases as the sensed motor speed of the drive motor increases. In some embodiment, to determine the proportional term adjustment factor, the electronic controller maps the sensed motor speed to the proportional term adjustment factor values using a map, the map including at least maximum adjustment factor region, a linear adjustment factor region, and a minimum adjustment factor region, the maximum adjustment factor region associates sensed motor speeds below a minimum speed threshold to a maximum proportional term adjustment factor value, the minimum adjustment factor region associates sensed motor speeds above a maximum speed threshold to a minimum proportional term adjustment factor value, and the linear adjustment factor region associates sensed motor speed between the minimum speed threshold and the maximum speed threshold to a value between the maximum and minimum proportional term adjustment factor values. In some embodiments, the linear adjustment factor region includes at least a first linear mapping sub-region and a second linear mapping sub-region, the first linear mapping sub-region mapping sensed motor speeds in a first range to linear adjustment factor values according to a linear function having a first slope, and the second linear mapping sub-region mapping sensed motor speeds in a second range to linear adjustment factor values according to a linear function having a second slope.
In another aspect, the invention provides a method of controlling an electric lawn mower, the method comprising: determining, by an electronic controller, a desired motor speed based on an output from a maneuvering control, the maneuvering control configured to indicate a desired motor control for a drive motor mounted to a frame of the electric lawn mower and driving rotation of a drive wheel supporting the frame to move the electric lawn mower over a ground surface; determining, by the electronic controller, a sensed motor speed based on an output of a motor speed sensor configured to sense a rotational speed of the drive motor; determining, by the electronic controller, a proportional term adjustment factor based on the sensed motor speed; and controlling, by the electronic controller, the drive motor according to a proportional integral drive control loop having a proportional term and an integral term, wherein the proportional term is determined based on a difference between the desired motor speed and the sensed motor speed and based on the proportional term adjustment factor.
In some embodiments, the method further comprises determining, by the electronic controller, a desired motor speed for a second drive motor based on an output from a second maneuvering control, the second maneuvering control configured to indicate a desired motor control for the second drive motor mounted to the frame of the electric lawn mower and driving rotation of a second chive wheel supporting the frame to move the electric lawn mower over the ground surface; determining, by the electronic controller, a sensed motor speed of the second drive motor based on an output of a second motor speed sensor configured to sense a rotational speed of the second drive motor; determining, by the electronic controller, a second proportional term adjustment factor based on the sensed motor speed of the second drive motor; and controlling, by the electronic controller, the second drive motor according to a second proportional integral drive control loop having a second proportional term and a second integral term, wherein the second proportional term is determined based on a difference between the desired motor speed for the second drive motor and the sensed motor speed of the second rive motor and based on the second proportional term adjustment factor. In some embodiments, the method further comprises providing electrical power, by a battery pack connected to a battery docking station of the lawn mower, to the drive motor and to a deck motor mounted to a cutting deck of the lawn mower; and controlling, by the electronic controller, the deck motor to drive rotation of a blade under the cutting deck to cut grass under the cutting deck. In some embodiments, controlling the drive motor according to the proportional integral drive control loop further includes: determining an integral term based on differences between desired motor speeds and sensed motor speeds over time; summing the integral term and the proportional term to generate a motor control signal for the drive motor; and controlling the drive motor based on the motor control signal. In some embodiments, the drive motor is a brushless motor and controlling the drive motor based on the motor control signal includes providing a pulse width modulated (PMW) signal as the motor control signal. In some embodiments, determining the proportional term includes multiplying the difference between the desired motor speed and the sensed motor speed by the proportional term adjustment factor. In some embodiments, the proportional term adjustment factor increases as the sensed motor speed of the drive motor decreases and decreases as the sensed motor speed of the drive motor increases. In some embodiments, determining the proportional term adjustment factor includes: mapping, by the electronic controller, the sensed motor speed to the proportional term adjustment factor values using a map, the map including at least maximum adjustment factor region, a linear adjustment factor region, and a minimum adjustment factor region, the maximum adjustment factor region associates sensed motor speeds below a minimum speed threshold to a maximum proportional term adjustment factor value, the minimum adjustment factor region associates sensed motor speeds above a maximum speed threshold to a minimum proportional term adjustment factor value, and the linear adjustment factor region associates sensed motor speed between the minimum speed threshold and the maximum speed threshold to a value between the maximum and minimum proportional term adjustment factor values. In some embodiments, the linear adjustment factor region includes at least a first linear mapping sub-region and a second linear mapping sub-region, the first linear mapping sub-region mapping sensed motor speeds in a first range to linear adjustment factor values according to a linear function having a first slope, and the second linear mapping sub-region mapping sensed motor speeds in a second range to linear adjustment factor values according to a linear function having a second slope.
In another aspect, the invention provides an off-board charger for charging a battery of an electric vehicle removed from the electric vehicle, the off-board charger comprising a frame; a resting support supporting the frame above a ground surface when the off-board charger is in a resting position; a pair of wheels position at a first end of the frame, the frame configured to pivot about an axis of the pair of wheels to lift the resting support off of the ground surface to enable wheeled transport of the off-board charger; a battery compartment supported by the frame and defining an inner space; a battery docking station mounted to a bottom wall of the battery compartment in the inner space; a battery pack connected to the docking station through a gravity-biased connection; and a charging circuit supported by the frame and having a power input connector and a power output connector, the power input connector configured to receive power from an external source, the power output connector configured to provide charging current to the battery pack.
In some embodiments, the off-board charger further comprises a lid for the battery compartment, the lid movable between an open position to provide access to the inner space and a closed position to restrict access to the inner space. In some embodiments, the off-board charger further comprises a lid sensor configured to provide a signal to the battery pack indicative of whether the lid is closed. In some embodiments, charging of the battery pack is disabled when the lid sensor indicates that the lid is open. In some embodiments, the battery pack weighs less than fifty pounds. In some embodiments, the docking station includes an alignment structure and an electrical connector, the alignment structure aligning the battery pack with the electrical connector prior to the battery pack engaging the electrical connectors as the battery pack is connected to the docking station. In some embodiments, the off-board charger further comprises a second charging circuit supported by the frame and having a second power input connector and a second power output connector, the second power input connector configured to receive power from the external source, the second power output connector configured to provide charging current to the battery pack. In some embodiments, the power input connector and the second power input connector are configured to be independently coupled to the external source via a first power cable coupled to the power input connector and extending away from the off-board charger and a second power cable coupled to the second power input connector and extending away from the off-board charger. In some embodiments, the battery docking station comprises a plurality of battery docking stations mounted to a bottom wall of the battery compartment; and the battery pack comprises a plurality of battery packs connected to the battery docking stations. In some embodiments, a bus bar connecting the plurality of docking stations to the charger, where the bus bar includes a printed circuit board with signal traces for communications and conductive plates for transmitting charging current, the conductive plates mounted on the printed circuit board. In some embodiments, the bus bar connecting the plurality of docking stations to a second charger. In some embodiments, a weight of the plurality of battery packs provides a gravity-biased connection between each of the plurality of battery packs and the plurality of docking stations such that the plurality of battery packs are removable from engagement with the plurality of docking stations without the need for tools. In some embodiments, each of the plurality of battery packs includes a handle integrally formed with an upper portion of the battery pack to facilitate handling of the battery pack by a user. In some embodiments, each of the plurality of docking stations includes contacts; each of the plurality of battery packs includes a flat bottom, a recessed portion, and contacts in the recessed portion; and contacts of the battery packs engage the contacts of the docking stations with a majority of the weight of the battery packs being borne by the flat bottom of the battery packs engaging a bottom of the battery compartment when the battery packs are lowered onto the docking stations. In some embodiments, the off-board charger further comprises a handle coupled to the first end of the frame, the handle configured to receive a force transverse to the handle to thereby pivot the frame about the axis of the pair of wheels to lift the resting support off of the ground surface to enable wheeled transport of the off-board charger. In some embodiments, the handle pivotably supported by the frame and has a storage position and a transport position, wherein, in the storage position, the handle is at a first pivot angle relative to the frame and, in the transport position, the handle is at a second pivot angle relative to the frame. In some embodiments, the off-board charger further comprises a handle support structure coupled to the battery compartment, and an adjustment mechanism coupled to the handle support structure, wherein the adjustment mechanism is configured to selectively engage with the handle to restrict pivotably movement of the handle between the storage position and the transport position.
In another aspect, the invention provides an electronic device for charging an electric vehicle battery, the electronic device comprises: a frame; a battery compartment supported by the frame and defining an inner space; a lid for the battery compartment, the lid movable between an open position to provide access to the inner space and a closed position to restrict access to the inner space; a battery docking station in the inner space of the battery compartment; a battery pack connected to the docking station, the battery pack having an electronic controller, a pack out terminal configured to provide an output signal, a wake terminal configured to receive a wake signal, and a safety terminal configured to receive a safety signal, the battery pack configured to power a motor of an electric vehicle; and a safety circuit having a connector that connects the pack out terminal to the wake terminal to provide the output signal to the battery pack as the wake signal, and a lid sensor configured to provide a safety signal to the battery pack indicative of whether the lid is closed; and a charging circuit having a power input connector and a power output connector, the power input connector configured to receive power from an external source, the power output connector configured to provide charging current to the battery pack, the electronic controller of the battery pack is configured to enable charging of the battery pack in response to receipt of the wake signal and the safety signal indicating that the lid is closed.
In some embodiments, the lid sensor includes a lid switch having an input terminal and an output terminal, the lid switch configured to close when the lid is in the closed position to make a connection between the input terminal and the output terminal, and open when the lid is in the open position to interrupt the connection between the input terminal and the output terminal. In some embodiments, the lid switch is a magnetically actuatable switch that is actuated to close when a magnet positioned on the lid is positioned within a range of the lid switch when the lid is closed, and that is actuated to open when a magnet positioned on the lid is positioned outside of the range of the lid switch when the lid is open. In some embodiments, the lid switch is a mechanically actuatable switch that is mechanically actuated to close when the lid is closed, and that is mechanically actuated to open when the lid is open. In some embodiments, the safety circuit provides a connection between the pack out terminal and the input terminal of the lid switch. In some embodiments, the connector that connects the pack out term inal to the wake terminal is a jumper in a charger plug that connects a charger circuit to the off-board charger. In some embodiments, the electronic controller is coupled to the pack out terminal, the wake terminal, and the lid terminal, and wherein the electronic controller is configured to: generate the output signal provided at the pack out terminal; and wake the battery pack in response to receipt of the wake signal. In some embodiments, the electronic device is an off-board charger separate from the electric vehicle. In some embodiments, the electronic device is a mower having the motor, and the electronic controller is further configured to: enable discharging of the battery pack in response to receipt of the wake signal and the safety signal; and provide current from cell so the battery pack to the motor after the enabling of discharging.
In another aspect, the invention provides a method for charging or discharging a battery of an electric vehicle, the method comprises receiving, at a docking station of the electric vehicle or an off-board charger, a battery pack, the docking station positioned in an inner space of a battery compartment of an electronic device, and the battery pack having an electronic controller, a pack out terminal, a wake terminal, and a safety terminal; providing, by the electronic controller, an output signal via the pack out terminal to a safety circuit of the electronic device; receiving, by the electronic controller, the output signal from the safety circuit as a wake signal via the wake terminal; receiving, by the electronic controller, a safety signal from a lid sensor via the safety terminal, the safety signal indicative of whether a lid for the battery compartment is closed; enabling charging of the battery pack, by the electronic controller, in response to receipt of the wake signal and the safety signal; and receiving, by the battery pack, charge current from a charging circuit after the enabling of charging.
In some embodiments, the docking station is of the electric vehicle, the method further comprises enabling discharging of the battery pack, by the electronic controller, in response to receipt of the wake signal and the safety signal; and providing, by the battery pack, current to a motor of the electric vehicle after the enabling of discharging. In some embodiments, the lid sensor includes a lid switch having an input terminal and an output terminal, the method further comprises closing, by the lid switch, when the lid is in a closed position to make a connection between the input terminal and the output terminal, and opening, by the lid switch, when the lid is in an open position to interrupt the connection between the input terminal and the output terminal. In some embodiments, the lid switch is a magnetically actuatable switch that is actuated to close when a magnet positioned on the lid is positioned within a range of the lid switch when the lid is closed, and that is actuated to open when a magnet positioned on the lid is positioned outside of the range of the lid switch when the lid is open. In some embodiments, the lid switch is a mechanically actuatable switch that is mechanically actuated to close when the lid is closed, and that is mechanically actuated to open when the lid is open. In some embodiments, the safety circuit provides a connection between the pack out terminal and the input terminal of the lid switch. In some embodiments, receiving, by the electronic controller, the output signal from the safety circuit as the wake signal via the wake terminal includes: providing, by a connector of the safety circuit, the output signal as the wake signal to the wake terminal, wherein the connector is a jumper in a charger plug that connects a charger circuit to the off-board charger. In some embodiments, the method further comprises waking, by the electronic controller, the battery pack in response to receipt of the wake signal and the safety signal.
In another aspect, the invention provides an electric vehicle comprises a frame; a chive wheel supporting the frame above a ground surface; a drive motor mounted to the frame and driving rotation of the drive wheel to move the electric vehicle over the ground surface; a control arm coupled to the frame at a pivot joint enabling the control arm to pivot about the pivot joint through a range of motion that includes a forward range of positions, a neutral position, and a reverse range of positions; a position sensor configured to indicate an angular position of the control arm in the range of motion: an electronic controller in communication with the position sensor and configured to: operate in a calibration mode, in response to a request received via a user interface, in which the electronic controller is configured to: inhibit driving of the drive motor, identify a neutral set parameter based on a first output value from the position sensor associated with a neutral position of the control arm, identify a forward set parameter based on a second output value from the position sensor associated with a maximum forward position of the control arm, identify a reverse set parameter based on a third output value from the position sensor associated with a maximum reverse position of the control arm; and operate in a drive mode in which the electronic controller is configured to control the drive motor in accordance with the angular position of the control arm indicated by the position sensor, the neutral set parameter, the forward set parameter, and the reverse set parameter.
In some embodiments, in the calibration mode, the electronic controller is further configured to: determine a neutral deadband based on the neutral set parameter, determine a maximum forward deadband based on the forward set parameter, and determine a maximum reverse deadband based on the reverse set parameter; and wherein, in the drive mode, the electronic controller is further configured to control the drive motor in accordance with the angular position of the control arm indicated by the position sensor, the neutral deadband, the maximum forward deadband, and the maximum reverse deadband. In some embodiments, to control the drive motor in accordance with the angular position of the control arm indicated by the position sensor, the neutral deadband, the maximum forward deadband, and the maximum reverse deadband, the electronic controller is further configured to: not drive the drive motor when the output value from the position sensor is within the neutral deadband, drive the drive motor at a maximum forward level when the output value from the position sensor is within the maximum forward deadband, and drive the drive motor at a maximum reverse level when the output value from the position sensor is within the maximum reverse deadband. In some embodiments, to identify the neutral set parameter, the electronic controller is configured to average output values from the position sensor over a period while the control arm is in the neutral position, wherein, to identify the forward set parameter, the electronic controller is configured to detect the output value from the position sensor that has the greatest difference from the neutral set parameter while the control arm is in the forward range, and wherein, to identify the reverse set parameter, the electronic controller is configured to detect the output value from the position sensor that has the greatest difference from the neutral set parameter while the control arm is in the reverse range. In some embodiments, to identify the forward set parameter, the electronic controller is further configured to determine that the output value from the position sensor that has the greatest difference from the neutral set parameter while the control arm is in the forward range exceeds a minimum forward threshold value, and, to identify the reverse set parameter, the electronic controller is further configured to determine that the output value from the position sensor that has the greatest difference from the neutral set parameter while the control arm is in the reverse range exceeds a minimum reverse threshold value. In some embodiments, in the calibration mode, the electronic controller is configured to: provide a first prompt on a display of the user interface to release the control arm into the neutral position before identifying the neutral set parameter, provide a second prompt on the display of the user interface to move the control arm to the maximum forward position before identifying the forward set parameter, and provide a third prompt on the display of the user interface to move the control arm to the maximum reverse position, before identifying the reverse set parameter. In some embodiments, the position sensor has a position map that maps potential sensed angles of the control arm to respective output values, and wherein, in the calibration mode, the electronic controller is further configured to: update the position map of the position sensor to map a midpoint output value of the position sensor to the neutral position of the control arm, update the forward set parameter based on an offset from the neutral set parameter and the midpoint output value, update the reverse set parameter based on the offset, and update the neutral set parameter to be the midpoint output value. In some embodiment, in the calibration mode, the electronic controller is further configured to: determine a neutral deadband based on the neutral set parameter after the neutral set parameter is updated to be the midpoint output value, determine a maximum forward deadband based on the forward set parameter after the forward set parameter is updated based on the offset, and determine a maximum reverse deadband based on the reverse set parameter after the reverse set parameter is updated based on the offset; and wherein, in the drive mode, the electronic controller is further configured to control the drive motor in accordance with the angular position of the control arm indicated by the position sensor, the neutral deadband, the maximum forward deadband, and the maximum reverse deadband. In some embodiments, the control arm is a left control arm, drive motor is a left drive motor, and the drive wheel is a left drive wheel, and the electric vehicle further comprises: a light drive wheel supporting the frame above the ground surface; a right drive motor mounted to the frame and driving rotation of the right drive wheel to move the electric vehicle over the ground surface: a right control arm coupled to the frame at a second pivot joint enabling the right control arm to pivot about the second pivot joint through a range of motion that includes a second forward range of positions, a second neutral position, and a second reverse range of positions; a second position sensor configured to indicate an angular position of the right control arm in the range of motion; wherein the electronic controller is further configured to: while operating in the calibration mode; inhibit driving of the light chive motor, identify a second neutral set parameter based on a first output value from the second position sensor associated with a neutral position of the right control arm, identify a second forward set parameter based on a second output value from the second position sensor associated with a maximum forward position of the right control arm, identify a second reverse set parameter based on a third output value from the second position sensor associated with a maximum reverse position of the right control arm; and while operating in the drive mode; control the right drive motor in accordance with the angular position of the right control arm indicated by the second position sensor, the second neutral set parameter, the second forward set parameter, and the second reverse set parameter.
In another aspect, the invention provides a method of calibrating a drive control for an electric vehicle having a frame, a drive wheel supporting the frame above a ground surface, and a drive motor mounted to the frame and configured to drive rotation of the drive wheel to move the electric vehicle over the ground surface, the method comprising: operating in a calibration mode, by an electronic controller of the electric vehicle, in response to a request received via a user interface of the electric vehicle; while in the calibration mode; inhibiting driving of the drive motor; identifying a neutral set parameter based on a first output value from a position sensor associated with a neutral position of a control arm, wherein the control arm is coupled to the frame at a pivot joint enabling the control arm to pivot about the pivot joint through a range of motion that includes a forward range of positions, a neutral position, and a reverse range of positions, and wherein the position sensor is configured to indicate an angular position of the control arm in the range of motion; identifying a forward set parameter based on a second output value from the position sensor associated with a maximum forward position of the control arm, identify a reverse set parameter based on a third output value from the position sensor associated with a maximum reverse position of the control arm; and operating in a drive mode, by the electronic controller; while in the drive mode; determining, by the electronic controller, an angular position of the control arm indicated by the position sensor; and controlling the drive motor in accordance with the angular position of the control arm indicated by the position sensor, the neutral set parameter, the forward set parameter, and the reverse set parameter.
In some embodiments, the method further comprises while in the calibration mode: determining a neutral deadband based on the neutral set parameter, determining a maximum forward deadband based on the forward set parameter, and determining a maximum reverse deadband based on the reverse set parameter; and while in the drive mode; controlling the drive motor in accordance with the angular position of the control arm indicated by the position sensor, the neutral deadband, the maximum forward deadband, and the maximum reverse deadband. In some embodiments, controlling the drive motor in accordance with the angular position of the control arm indicated by the position sensor, the neutral deadband, the maximum forward deadband, and the maximum reverse deadband further comprises: not driving the drive motor when the output value from the position sensor is within the neutral deadband, driving the drive motor at a maximum forward level when the output value from the position sensor is within the maximum forward deadband, and driving the drive motor at a maximum reverse level when the output value from the position sensor is within the maximum reverse deadband. In some embodiments, identifying the neutral set parameter further includes averaging output values from the position sensor over a period while the control arm is in the neutral position, wherein identifying the forward set parameter further includes detecting the output value from the position sensor that has a greatest difference from the neutral set parameter while the control arm is in the forward range, and wherein identifying the reverse set parameter further includes detecting the output value from the position sensor that has a greatest difference from the neutral set parameter while the control arm is in the reverse range. In some embodiments, identifying the forward set parameter further includes determining that the output value from the position sensor that has the greatest difference from the neutral set parameter while the control arm is in the forward range exceeds a minimum forward threshold value, and wherein identifying the reverse set parameter further includes determining that the output value from the position sensor that has the greatest difference from the neutral set parameter while the control arm is in the reverse range exceeds a minimum reverse threshold value. In some embodiments, the method further comprises, while in the calibration mode: providing a first prompt on a display of the user interface to release the control arm into the neutral position before identifying the neutral set parameter, providing a second prompt on the display of the user interface to move the control arm to the maximum forward position before identifying the forward set parameter, and providing a third prompt on the display of the user interface to move the control arm to the maximum reverse position, before identifying the reverse set parameter. In some embodiments, the position sensor has a position map that maps potential sensed angles of the control arm to respective output values, and the method further comprises, while in the calibration mode: updating the position map of the position sensor to map a midpoint output value of the position sensor to the neutral position of the control arm, updating the forward set parameter based on an offset from the first output value and the midpoint output value, updating the reverse set parameter based on the offset, and updating the neutral set parameter to be the midpoint output value. In some embodiments, the method further comprises while in the calibration mode: determining a neutral deadband based on the neutral set parameter after the neutral set parameter is updated to be the midpoint output value, determining a maximum forward deadband based on the forward set parameter after the forward set parameter is updated based on the offset, and determining a maximum reverse deadband based on the reverse set parameter after the reverse set parameter is updated based on the offset; and while in the drive mode: controlling the drive motor in accordance with the angular position of the control arm indicated by the position sensor, the neutral deadband, the maximum forward deadband, and the maximum reverse deadband. In some embodiments, the control arm is a left control arm, drive motor is a left drive motor, and the drive wheel is a left drive wheel, and the electric vehicle further includes a right control arm coupled to the frame at a second pivot joint enabling the right control aim to pivot about the second pivot joint through a second range of motion that includes a second forward range of positions, a second neutral position, and a second reverse range of positions, and a second position sensor configured to indicate an angular position of the right control arm in the second range of motion, the method further comprising, while in the calibration mode: inhibiting driving of the right drive motor; identifying a second neutral set parameter based on a first output value from the second position sensor associated with a second neutral position of the right control arm, identifying a second forward set parameter based on a second output value from the second position sensor associated with a maximum forward position of the right control arm, identify a second reverse set parameter based on a third output value from the second position sensor associated with a maximum reverse position of the right control arm; while in the drive mode: determining, by the electronic controller, an angular position of the right control arm indicated by the second position sensor; and controlling the right drive motor in accordance with the angular position of the right control arm indicated by the second position sensor, the second neutral set parameter, the second forward set parameter, and the second reverse set parameter.
Other aspects of the invention will become apparent by consideration of the detailed description and accompanying drawings.
Before any embodiments of the invention are explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the following drawings. The invention is capable of other embodiments and of being practiced or of being carried out in various ways. As used herein, terms relating to position (e.g., front, rear, left, right, etc.) are relative to an operator situated on a utility vehicle during normal operation of the utility vehicle.
One problem addressed with the present invention arises from the nature of a connection interface to allow a power source to be removed from a battery compartment of a lawn mower. Such a power source includes, among other elements as will be explained below, a plurality of battery packs that form a gravity-biased connection with a battery interface. The gravity biased connection ensures that the batteries are always biased into contact during ordinary operation of the lawn mower. The gravity-biased connection of the battery packs also facilitates relatively easy removal the battery packs from the lawn mower.
Another problem addressed with the present invention arises from the nature of managing a priority charging method of the plurality of battery pack with an electronic control module (e.g., a vehicle control module, battery control module, etc.). When battery packs are at a low state of charge, lawn mowers typically cannot operate at a desired performance level (e.g., cutting or driving speed). This poses problems when a user desires to quickly charge the lawn mower. To improve the performance of the lawn mower, the electronic control module manages the priority charging method to charge the battery packs having a state of charge above a predetermined threshold first. As a result, the lawn mower may be operated at the desired performance level for a longer time.
Another problem addressed with the present invention arises from the nature of electric vehicles being very quiet during operation. As a result, the likelihood that the user is unaware that the vehicle has started or is in an operational state increases. The vehicle control module manages a live to drive system that includes an audible element and a user display. When the lawn mower is being started, the live to dive system alerts the user with a visual alert using the user display and audible alert using the audible element. As a result, the user is alerted that the vehicle is in an operational state.
Another problem addressed with the present invention arises from navigating the lawn mower in a tight area (e.g., between obstacles such as trees, rocks, etc.). The lawn mower includes an adjustment mechanism that interacts with the vehicle control module and maneuvering controls of the lawn mower to variably limit the maximum speed of the lawn mower. The adjustment mechanism may, for example be a dial that is adjustable between a plurality of positions. When the dial is adjusted to a desired position, the maximum speed of the lawn mower is adjusted to a desired maximum speed. The precision of the maneuvering controls increases as the maximum speed is decreased to allow the user to perform a precise maneuver in the tight area.
The frame 20 includes a first or front portion 22 (extending to the center of the frame) and a second or rear portion 24 (meeting the front portion at the center of the frame) opposite the front portion 22. The frame 20 defines the basic body structure or chassis of the lawn mower 10 and supports the other components of the lawn mower 10. The frame 20 is supported by the ground engaging elements 30, 35 and in turn supports the other components of the lawn mower 10.
The ground-engaging elements 30, 35 are movably (e.g., rotatably) coupled to the frame 20. The illustrated ground-engaging elements 30, 35 include two first or front ground-engaging elements 30 coupled to the front portion 22 of the frame 20, and two second or rear ground-engaging elements 35 coupled to the rear portion 24 of the frame 20. In the illustrated embodiment, the ground-engaging elements 30, 35 are rotatable wheels but in other embodiments could be tracks for example. In the illustrated embodiment, the first (front) ground-engaging elements 30 are passive (i.e., rotating in response to movement of the lawn mower) caster wheels and the second (rear) ground-engaging elements 35 are the driven (i.e., rotating to cause movement of the lawn mower) wheels rotating under the influence of the prime mover 45. The second (rear) ground-engaging elements 35 may be referred to in the illustrated embodiment as the drive wheels or the left and right drive wheels 35, it being understood that the terms “left” and “right” are from the perspective of an operator in an ordinary operating position on the lawn mower. The drive wheels 35 are rotated by the prime mover 45 at a selected speed and direction to effect movement and steering of the lawn mower 10 in the well-known manner of a zero turn radius lawn mower. In other embodiments, similar prime movers 45 may also or alternatively be coupled to the two first ground-engaging elements 30 for the same purpose as the prime movers 45. In other embodiments, the lawn mower may take the form of a stand-on mower or a tractor-style mower with steerable wheels.
The prime mover 40, 45 may, for example, be an internal combustion engine, one or more electric motors, hybrid gas/electric, etc. With reference to
Turning now to
With reference to
The user interface 70 (schematically illustrated in
The system interface 74 may include an ignition 76, a user display 78, and control switches 79 (e.g., adjustment switches in the form of dials, push buttons, etc., which will be described in more detail below). The ignition 76 communicates with the vehicle control module 90 to allow the user to selectively provide power to (i.e., activate) the drive motors 45 and the deck motors 40. In some embodiments, ignition 76 include separate switches that activate the drive motors 45 and the deck motors 40 independently or by group. In the illustrated embodiment, the battery packs 52, 54, 56, 58 communicate directly with the user display 78 (e.g., via CAN communication) to display battery-related information on the user display 78. In other embodiments, the user display 78 communicates with the vehicle control module 90 to display information to the user. For example, the user display 78 may display a state of charge of the power source 50, faults occurring on the mower (e.g., battery pack faults), an operational state of the lawn mower 10, etc. The control switches 79 and the user display 78 may interact with the vehicle control module 90 to control functions of the mower 10 (e.g., activation of deck motor 40, drive motors 45, maximum variable speed, etc.).
With reference to
The vehicle control module 90 may interact with the user interface 70, the drive motors 45 (e.g., via a drive motor controller), and the deck motors 40 (e.g., via a deck motor controller) during operation of the mower 10. More specifically, the vehicle control module 90 may take input from the system interface 74 and relay instructions to the drive motors 45 and the deck motors 40. The vehicle control module 90 may also receive information from the power source 50, such as state of charge of the batteries and other battery-related information, and relay this information to the user interface 70. The user display 78 may display information to the user such as state of charge of the power source 50, operation mode of mower 10, etc., as described in more detail below. While lawn mower 10 is described above as an electric zero turn lawn mower, it should be appreciated that the battery assembly and/or control systems described below may be used with any utility device that is operable to cut grass.
Power SourceNow referring to
Referring now to
As illustrated in
The battery interface 120 is adapted to receive a plurality of battery packs 52, 54, 56, 58, which together are referred to as a bank of battery packs 50. In the illustrated embodiment, the bank of battery packs 50 includes four battery packs 52, 54, 56, 58 to match the four docking stations 122 of the battery interface 120.
The illustrated enclosure 130 has a height of approximately sixteen inches and a width and depth of approximately nine inches. The size of the enclosure 130 allows each battery pack 52, 54, 56, 58 to have a weight under approximately 55 pounds. The weight of the battery pack 52, 54, 56, 58 and vertical orientation of the battery pack 52, 54, 56, 58 in the battery compartment 100 ensure a gravity-biased connection is formed between the battery pack 52, 54, 56, 58 and the docking station 122. As used herein, “gravity-biased” means that the influence of gravity holds or urges the battery pack 52, 54, 56, 58 into engagement with the docking station 122 during loading of the battery pack 52, 54, 56, 58 or during ordinary operation of the lawn mower. The battery pack 52, 54, 56, 58 may also be secured with another mechanism such as the latch 106 discussed above, but the latch 106 does not work against gravity (and may, indeed work with gravity) when the battery pack 52, 54, 56, 58 is gravity-biased into engagement with the docking station 122. For example, the engagement of the latch 106 secures the lid 104 in the closed condition such that the lid 104 engages the battery pack 52, 54, 56, 58 to form a gravity-assisted connection force that works with the gravity-biased connection of the battery packs 52, 54, 56, 58 to urge the battery packs 52, 54, 56, 58 into engagement with the docking station 122. In some embodiments, the lid 104 may not contact the battery packs 52, 54, 56, 58 when the latch 106 is secured and the gravity-biased connection of the battery packs 52, 54, 56, 58 may secure the battery packs 52, 54, 56, 58 to the docking station 122 (i.e., without the gravity-assisted force).
Additionally, interference and frictional engagements between the battery packs 52, 54, 56, 58 and portions of the battery compartment 100 and docking stations 122 may arise as the battery packs 52, 54, 56, 58 are lowered or dropped into position under the influence of gravity. Such engagements are deemed part of the gravity-biased connection because they are incidental and no other positive action must be taken or other securing mechanism actuated to secure the battery packs 52, 54, 56, 58 into position other than lowering them onto the docking stations 122. In some embodiments, the battery pack 52, 54, 56, 58 may receive an additional force (i.e., a gravity assisted connection force) from the operator to overcome the frictional engagement between the battery pack 52, 54, 56, 58 and the docking station 122.
Referring now to
The button 152 interacts with the set of LEDs 148 to indicate the state of charge of each battery pack 52, 54, 56, 58 and whether there is a fault occurring within the battery pack 52, 54, 56, 58. For example, the set of LEDs 148 may include five LEDs that illustrate various charge levels (e.g., 80-100 percent when all 5 LED's are lit, 60-80 percent when four LED's are lit, etc.) when the LED's illuminate a first color (e.g., green, blue, etc.). Additionally, the one or more of the LEDs 148 may illuminate in a second color (e.g., red) when the battery pack has a low charge level (e.g., under 10 percent) or if a fault occurs (e.g., the cells are under-temperature, the cells are over-temperature, a fuse is blown, etc.).
Referring now to
When the battery pack 52, 54, 56, 58 is secured to the docking station 122 (
Referring now to
The lawn mower 10 includes a priority charging method, a live to drive system, and a variable speed control system. The bank of battery packs 50 coupled to the bus bar 131 may communicate directly with a charger 210 to determine the priority charge method. In other embodiments, the bank of battery packs may communication with the vehicle control module 90 to determine the priority charging method. In other embodiments, the vehicle control module 90 communicates with the live to drive system 300 to alert the user when the lawn mower 10 is in an operable state. In yet another embodiment, the vehicle control module 90 communicates with the variable speed control system 400 to control the sensitivity of the maneuvering controls 72 to allow the user of the lawn mower to navigate the lawn mower in a tight area (e.g., between obstacles such as trees, rocks, etc.).
Priority Charging MethodIn some embodiments, the AC input power for each charger 212, 213 is provided from an independent circuit of the external power source 211. Accordingly, the overall current that the charger configuration 210 may draw from the external power source 211 without tripping a circuit breaker may be larger (e.g., at 30 or 40 Amps) than if a single connection was provided to the external power source 211 for both chargers 212, 213. Additionally, because each charger 212, 213 is connected to an independent circuit, even if one circuit breaker trips for one of the circuits, the other circuit may still be providing power and the charger configuration 210 may be able to continue to provide charging current.
The charging port 220 includes a first charging port 224 and a second charging port 228. The first and second charging plugs 214, 218 are selectively coupled (e.g. plugged in) by a user to the first and second charging port 224, 228 to provide charging power to the charging port 220. The first and second charging plugs 214, 218 may also be selectively removed (e.g., unplugged) by a user when, for example, the respective first and second chargers 212, 213 are not providing charging current to the charging port 220.
In some embodiments, the charger configuration 210 may include a charger housing (not shown) that houses the first charger 212 and the second charger 213. In such embodiments, the first charging plug 214 and the second charging plug 218 may each have a first end respectively coupled to the first and second chargers 212, 213 within the housing, and a second end that extends away from the housing to enable respective coupling to the first and second charging ports 224, 228. In some embodiments, the charger housing is mounted onto the mower 10, while in other embodiments, the charger housing is separate from the mower 10. In some embodiments, the first charger 212 and second charger 213 have separate housings, rather than a shared housing, which may either be mounted onto the mower 10 or separate from the mower 10.
In some embodiments, as shown in
As noted, the power source 250 includes a bank of one or more batteries (e.g., the battery packs 52, 54, 56, 58), one of which may be identified as a master battery pack 252 and the remaining ones of which may be identified as a plurality of slave battery packs 254, 256, 258 (e.g., three in the illustrated embodiment). In other embodiments, the power source 250 may include more (e.g., five, six, seven, etc.) or fewer battery packs (e.g., two, three, one).
In order to determine which battery pack 252, 254, 256, 258 is the master battery pack 252, an identification number is assigned to each battery pack 252, 254, 256, 258 (e.g., one, two, three, four, etc.). The battery pack 252, 254, 256, 258 with the lowest identification number, as identified by the vehicle control module 90, is selected as the master battery pack 252 and the remaining battery packs are slave battery packs 254, 256, 258. If the master battery pack 252 is removed from the battery interface, the vehicle control module 90 may automatically reassign the slave battery pack 254, 256, 258 with the lowest identification number to be the master battery pack 252. At the same time, if an additional battery pack is attached to the battery interface 120 with a lower identification number, the vehicle control module 90 may automatically assign the additional battery pack to be the master battery pack 252. Although the vehicle control module 90 is described as identifying the master and slave battery packs, in some embodiments, the battery packs themselves (without a separate controller such as the vehicle control module 90) perform the arbitration through communications to determine the master and slave battery packs. For example, each battery pack 252, 254, 256, and 258 may broadcast their own respective identification number, which is received by the other battery packs, and each battery pack 252, 254, 256, 258 determines whether its own identification number is the lowest of the numbers that were broadcast and, if so, designates itself as the master battery pack.
The master battery pack 252 communicates with the first and second charging ports 224, 228, the vehicle control module 90, and the slave battery modules 254, 256, 258 to determine the priority charging method. It should be appreciated that each of the battery packs 252, 254, 256, 258 has a state of charge. The master battery pack 252 may communicate with the first and second charging plugs 214, 218 to charge a single battery pack or a plurality of battery packs (e.g., two, three, four, etc.) in parallel.
The master battery pack 252 determines the priority charging method based on the state of charge level of the battery packs 252, 254, 256, 258. The master battery pack 252 automatically manages the priority charging method of the battery packs 252, 254, 256, 258 based on the state of charge of each battery pack 252, 254, 256, 258. The priority charging method includes: (1) determining the state of charge of the plurality of battery packs 252, 254, 256, 258, (2) comparing the state of charge of each of the plurality of battery packs 252, 254, 256, 258 to a predetermined threshold (e.g., in the exemplary embodiments 81 percent state of charge). (3) determining a first set of one or more battery packs with the state of charge above the predetermined threshold and a second set of one or more battery packs with the state of charge under the predetermined threshold, (4) charging the first set of one or more battery packs before charging the second set of one or more battery packs. The steps of priority charging method may be implemented by an electronic controller, such as the vehicle control module 90 or a battery controller of the master battery pack 252.
Exemplary state of charge arrangements of the bank of battery pack 250 are described below. It should be appreciated that while the bank of battery packs 250 is described as having first, second, third and fourth battery packs 252, 254, 256, 258, fewer or more battery packs may be charged.
In a first exemplary embodiment, the first, second, third and fourth battery packs 252, 254, 256, 258 each have a low state of charge (e.g., approximately 15 percent charge). When the charging commences, each of the first, second, third and fourth battery packs 252, 254, 256, 258 are charged concurrently.
In a second exemplary embodiment, the master battery pack 252 determines that the first, second, third and fourth battery packs 252, 254, 256, 258 each have various state of charges under a predetermined state of charge threshold. The predetermined threshold may be a state of charge of equal to or more than 81 percent. For example, the first, second, third, and fourth battery packs 252, 254, 256, 258 may have state of charge levels of 60 percent, 65 percent, 70 percent, and 75 percent, respectively.
In this example, the master battery pack 252 determines that the first battery pack 252 has the lowest state of charge level (60 percent). As a result, the first battery pack 252 is charged alone until the state of charge matches the second battery pack 254 (e.g., the second lowest state of charge). Once the first battery pack 252 has the same state of charge as the second battery pack 254, the first and second battery packs 252, 254 are charged concurrently. The first and second battery packs 252, 254 are charged concurrently until the state of the first and second battery packs 252, 254 matches the state of charge of the third battery pack 256. The first, second, and third battery packs 252, 254, 256 are charged concurrently until the state of the first, second, and third battery packs 252, 254, 256 matches the state of charge of the fourth battery pack 258. This sequence will continue until all the battery packs in the power source 250 are at the same state of charge.
In a third exemplary embodiment, the master battery pack 252 determines that one or more of the first, second, third and fourth battery packs 252, 254, 256, 258 has a state of charge level above the predetermined threshold (e.g., 81 percent). For example, the first, second, third, and fourth battery pack 252, 254, 256, 258 may include state of charge levels of 60 percent, 65 percent, 70 percent, and 85 percent, respectively. In this example, the master battery pack 252 determines the fourth battery pack 258 is above the predetermined threshold and causes charging of the fourth battery pack 258 until the battery pack 258 fully charged. Once the fourth battery pack 258, is fully charged, the first second, and third battery packs 252, 254, 256 are charged in the same fashion as described in the second exemplary state of charge of arrangement described above. In other embodiments, once the first, second, and third battery packs 252, 254, 256 reach the predetermined threshold, the master battery pack 252 may cause charging of a single battery pack at a time until each battery pack reaches a full charge.
In some embodiments, a user may remove or insert battery packs as the battery packs are being charged. The charging system 200 remains uninterrupted (e.g., continues to charge the battery packs) during the removal or insertion of the battery pack. In some embodiments, the removal or insertion of the slave battery pack 254, 256, 258 may change the priority charging method depending on the state of charge of the slave battery pack 254, 256, 258 being removed or inserted. However, removal or insertion of a new master battery pack 252 (e.g., a battery pack with a lower identification number) may momentarily stop charging until the new master battery module 252 assumes control of the priority charging method.
It should be appreciated that while the predetermined threshold is described above as a state of charge above 81 percent, that the predetermined threshold may be any state of charge that is determined to be close to fully charged. For example, the predetermined threshold may include a state of charge in a range from 70 percent to 99 percent. In other embodiments, the range may be from 75 percent to 90 percent. In other embodiments the range may be from 80 percent to 85 percent.
Live to DriveThe system interface 74, the maneuvering controls 72, and the audible element 310 are positioned within an operator zone of the lawn mower 10 so they can be reached by, seen by, or heard by the user while operating the lawn mower 10. The system interface 74 includes the ignition 76 having an ignition switch, a parking brake 330 (which may be one of the above-mentioned control switches 79), and the user display 78. In the illustrated embodiment, the maneuvering controls 72 in the form of left and right control arms 72a, 72b. The parking brake may include a parking sensor that is configured to indicate to the vehicle control module 90 whether the parking brake is activated. For example, the parking brake sensor may be a push-button style switch that is actuated when the parking brake is activated, and that is de-actuated when the parking brake is deactivated.
In the illustrated embodiment, the user display 78 communicates with the vehicle control module 90 to provide the visual alert to the user. For example, an indicator may be displayed on the user display 78 to alert the user of the operational state of the lawn mower. The indicator may be a LED, a message (e.g., text, an icon indicator, etc.), etc. Additionally, or alternatively, the system interface 74 may include an additional visual element 340 (e.g., a flashing light supported by the frame, etc.) that communicates with the vehicle control module 90 to provide the visual alert to the user. It should be appreciated that the broken lines of the additional visual element 340 illustrates the optionality of the additional visual element 340.
The audible element 310 communicates with the vehicle control module 90 to provide an audible alert to the user of the lawn mower 10. The audible element 310 may, for example, be one or more of a speaker supported by the lawn mower and a headset used by the user. The headset may communicate with the vehicle control module through a short-range wireless communication protocol (e.g., BLUETOOTH), a wired connection etc. As a result, the audible alert may be provided to the user in through any combination of the speaker and the headset. While the audible element 310 is described as a speaker and a headset, it will be appreciated that the audible element 310 may be any element that can communicate with the vehicle control module 90 to provide an audible alert to the user.
The plurality of sensors 320 determines operational states with the system interface 74, the maneuvering controls 72, the operator platform 60, and the power source 50. The vehicle control module 90 communicates with the plurality of sensors 320 to determine whether the operational states determined by the plurality of sensors 320 satisfy a set of predetermined conditions. When the set of predetermined conditions is satisfied, the vehicle control module 90 communicates with the user display 78 and an audible element 310 to alert the user with the visual alert (e.g., on the user display) and an audible alert (e.g., from the audible element) that the lawn mower 10 is in an operable state. In some embodiments, the vehicle control module 90 may communicate the visual alert with the additional visual element 340.
If any of the first subset of the predetermined conditions are not satisfied, the lawn mower 10 is off and driving is disabled (i.e., the lawn mower 10 is not in the live to drive state). As a result, the user display 78 is off and does not provide the visual alert to the user. In some embodiments, if the user attempts to drive the lawn mower (e.g., by adjusting the position of the maneuvering controls 72), the user display 78 may display a message relating to the reason the lawn mower 10 cannot be driven (e.g., parking brake is off, system fault occurred, etc.).
When the first subset of the predetermined conditions are satisfied, the vehicle control module 90, alerts the user that the lawn mower 10 is in an operable state. For example, the indicator on the user display 78 may flash (e.g., a flashing LED or message) that the lawn mower 10 is in the operable state, which is an intermediate state before reaching a live to drive state. In some embodiments, the indicator may flash at a rate of approximately 1 hertz. It should be appreciated that when the mower 10 is in the operable state, the power source 50 of the mower 10 is in electrical communication with the vehicle control module 90 and the drive controllers (e.g., of the deck and the drive motor 40, 45, etc.). However, further yet-to-be-satisfied predetermined conditions and safety features such as the parking brake 330, a power-take off switch (e.g., to control the deck motors 40) may restrict activation of the drive motors 45 or the deck motors 40.
Turning to
If all the second subset of the predetermined conditions of the redundant system check are satisfied, the vehicle control module 90 provides a series of alerts to the user. As noted, in step 354, the vehicle control module 90 controls the audible element 310 to provide an audible alert to the user. In
After the second audible alert, the user display 78 may provide the visual alert (in step 356). In the illustrated embodiment, the user display 78 displays a message saying the lawn mower is ready to be operated or is in the live to drive state. In step 358, as previously described with respect to
Once in the live to drive state, the vehicle control module 90 is configured to enable control of the deck motors 40 by the user (e.g., via the power-take off switch), the drive motors 45 (e.g., via disabling of the parking brake and operation of the maneuver controls 72) to drive a desired speed and direction, the headlights, and other features of the vehicle. In other words, the vehicle control module 90 is configured to cause the vehicle to enter the live to drive state and, thereby, to enable control of one or more of these noted features based on determining that the predetermined conditions are satisfied. In contrast, before the vehicle is in the live to drive state (before the predetermined conditions are satisfied), the vehicle control module 90 may prohibit control of the deck motors 40 and the drive motors 45, as well as other features (e.g., the headlights). For example, to prohibit control of these features, the vehicle control module 90 may effectively ignore signals received from the power take-off switch and maneuver controls 72, whereas, after entering the live to drive state, the vehicle control module 90 may receive such signals and send corresponding control signals to the deck motors 40 and drive motors 45 in response to signals received from the power take-off switch and maneuver controls 72.
In some embodiments, a sub-state of the live to drive state is a ready to drive state, which is entered by the vehicle after the parking brake 330 is disabled. For example, after providing the alerts in steps 354 and 356 and entering the live to drive state while in step 358, the parking brake 330 may still prevent driving of the vehicle via the drive motors 45 despite receiving signals from the maneuver controls 72 in response to user movement of the maneuver controls 72. Accordingly, while in the live to drive state, the vehicle control module 90 may determine that the parking brake 330 is disabled by the user and, in response, identify the vehicle as in the ready to drive state. In the ready to drive state, with the parking brake 330 disabled, the vehicle control module 90 controls the drive motors 45 in response to the maneuver controls 72 (i.e., to drive a desired speed and direction of rotation of the rear ground-engaging elements 35 to move and/or turn the lawn motor 10). In some embodiments, the parking brake 330 is a predetermined condition of step 352 that is determined to be satisfied before the vehicle control module 90 advances to steps 354, 356, and 358.
While the live to drive system 300 is described above as having two audible alerts and a delay. It should be appreciated that the live to drive system 300 may provide additional audible alerts or a continuous audible alert that is on until the user operates the lawn mower 10. Additionally, if the lawn mower 10 is in an operable state and the user is not operating the lawn mower 10 (e.g., the maneuvering controls 72 are in the neutral position), the vehicle control module 90 may alert the user after a predetermined time that the lawn mower 10 is still in the operable state. For example, this may occur when the user stops the mower 10 (e.g., to talk to someone, etc.) after operating the lawn mower 10.
Variable Speed Control SystemReferring now to
Referring to
The adjustment mechanism 410 is movable between a plurality of positions to allow the maximum speed of the lawn mower 10 to be variably adjusted to define an adjusted maximum speed. In a first exemplary embodiment, the adjustment mechanism 410 may include three positions such as a low maximum speed mode 420, a standard maximum speed mode 430 (e.g., referred to as standard operation), and a high maximum speed mode 440. For example, the adjustment mechanism 410 may move between detents that define fixed positions of the adjustment mechanism 410 related to the low, standard, or high maximum speed modes 420, 430, 440. In this embodiment, the adjusted maximum speed of the lawn mower 10 is fixed to three preset adjusted maximum speed modes.
In a second exemplary embodiment, the adjustment mechanism 410 may be variably moved between to any position from the low maximum speed mode 420 and the high maximum speed mode 440 (e.g., as the user turns the dial, the maximum speed setting goes up and down as a function of the amount the dial is rotated). In some constructions, the adjustment mechanism 410 may not include the preset adjusted maximum speed modes. In other constructions, the adjustment mechanism 410 may include detents (defining the fixed positions of the adjustment mechanism 410), similar to the first embodiment. As a result, the adjustment mechanism 410 may be positioned within any of the three preset adjusted maximum speed modes or moved within a variable speed zones 450 (e.g., between the detents that define the preset adjusted maximum speed modes) to select the adjusted maximum speed. As a result, the user is able to variably control the maximum speed of the lawn mower 10.
Referring to
The vehicle control module 90 may communicate with the user display 78 to provide a visual alert to the user relating to the adjusted maximum speed. For example, the visual alert may be a message or indicator displaying the adjusted maximum speed mode of the lawn mower 10 or a variable indicator (e.g., a bar, dial, etc. that corresponds position of adjustment mechanism).
In an exemplary embodiment, the lawn mower 10 is a zero turn lawn mower having maneuvering controls 72 in the form of left and right control anus 72a, 72b that are operably coupled to left and right drive wheels 35 (as described above with reference to
In one non-limiting example, the standard operation maximum speed (i.e., the left and right control arms 72a. 72b pushed fully forward) is eight miles per hour. When the user operates the mower in a precise maneuver (e.g., mowing around a tree or along a curved border), the user may use the adjustment mechanism 410 to set the maximum speed to the desired adjusted maximum speed. The adjusted maximum speed, for example may be five miles per hour. As a result, the vehicle control module 90 communicates with the left and right control arms 72a. 72b so when the control arms 72a, 72b are pushed halfway forward, the mower 10 travels at a speed of 2.5 miles per hour (half of the desired maximum speed). Alternatively, the mower 10 may travel at a speed that is non-linear as a function of the position of the control arms 72a, 72b. For example, the speed may increase more rapidly as the control arms 72a. 72b approach the end of their range of motion. The variable speed control system 400 therefore gives the user more precise control of the lawn mower 10 via manipulation of the control arms 72a, 72b during the precise maneuvers. Alternatively, the user may set the adjusted maximum speed to eleven miles per hour (e.g., the highest speed the lawn mower 10 may travel). In some instants, the user may be traveling substantially straight for a long distance or traveling without the deck motors 40 activated. As a result, the user may increase the adjusted maximum speed relative to standard operation.
With reference again to
The seat sensor 512 is configured to indicate to the mower electronic controller 500 whether an operator is in the seat 66. For example, the seat sensor 512 may be a push-button style switch that is actuated when a weight above a threshold amount is on the seat 66 (e.g., providing a signal to the mower electronic controller 500) and that is de-actuated when a weight less than the threshold amount is on the seat 66 (e.g., providing no signal to the mower electronic controller 500). The parking brake sensor 514 is configured to indicate to the mower electronic controller 500 whether the parking brake is activated. For example, the parking brake sensor 514 may be a push-button style switch that is actuated when the parking brake is activated, and that is de-actuated when the parking brake is deactivated. In some embodiments, other sensors types are used to implement one or both of the seat sensor 512 and the parking brake sensor 514.
The drive motor sensors 518 include one or more sensors to sense characteristics of an associated one of the drive motors 45. For example, and with reference to
With continued reference to
The motor controllers 505 include a drive motor controller 550a, a drive motor controller 550b, a deck motor controller 555a, a deck motor controller 555b, and a deck motor controller 555c. Each drive motor controller 550a and 550b is associated with a respective drive motor 45. Each deck motor controller 555a, 555b, and 555c is associated with a respective deck motor 40. The drive motor controllers 550a, 550b may also be referred to collectively as the drive motor controllers 550 and generically as the drive motor controller 550. The deck motor controllers 555a, 555b may also be referred to collectively as the deck motor controllers 555 and generically as the deck motor controller 555. In some embodiments, one or more of the drive motor controllers 550 and deck motor controllers 555 are combined into a single motor controller, such that the ratio of motor controllers to motors is less than one-to-one.
Each of the drive motor controllers 550 and the deck motor controllers 555 includes a respective electronic processor and a memory storing instructions that, when executed by the respective electronic processor, implement the functionality of the respective motor controllers described herein.
The chive motor controllers 550 are configured to receive a reference command from the vehicle control module 90 and, in response, control their respective drive motor 45 in accordance with the command. The reference command may indicate a desired speed, such as rotations per minute (RPM) or a percentage of a maximum speed (e.g., that is stored on a memory of the respective motor controller 550). In some embodiments, the reference command is an enable signal that causes the drive motor controller 550 to control the drive motor 45 (e.g., at a predetermined speed) or a disable signal that causes the drive motor controller 550 to control the chive motor 45 to stop. In some embodiments, the drive motor controllers 550 each include a proportional integral (PI) control loop 560. The PI control loop 560 may be, for example, implemented in software instructions stored on the memory and executed by the processor of each of the drive motor controllers 550. The PI control loop 560 is described in further detail with respect to
Similarly, the deck motor controllers 555 are configured to receive a reference command from the vehicle control module 90 and, in response, control their respective deck motor 40 in accordance with the command. The reference command may indicate a desired speed, such as rotations per minute (RPM) or a percentage of a maximum speed (e.g., that is stored on a memory of the respective motor controller 555). In some embodiments, the reference command is an enable signal that causes the deck motor controller 555 to control the deck motor 40 (e.g., at a predetermined speed) or a disable signal that causes the deck motor controller 555 to control the deck motor 40 to stop.
In some embodiments, the vehicle control module 90 is also configured to determine and communication maximum current levels for the deck motors 40 and drive motors 45, as described in further detail with respect to
The battery memory 610 stores instructions that, when executed by the battery electronic processor 605, implement the functionality of the battery controller 600 described herein. The SOC voltage sensor 620 is configured to measure the voltage across the cells 615 (e.g., at a positive and negative terminal point for the entire set of the cells 615) and to provide the voltage measurement to the battery controller 600, which is indicative of the state of charge of the cells 615 (and, thus, of the battery pack 252). The cell group voltage sensors 625 include a plurality of voltage sensors that each are configured to measure the voltage across a cell group of parallelly connected cells. For example, with reference to
Returning to
Returning to
In block 655, the mower electronic controller 500 determines a maximum steady state current value for the battery packs of the power source 250. For example, to determine the maximum steady state current value, the vehicle control module 90 of the mower electronic controller 500 may receive the maximum steady state current value from the master battery pack 252 of the power source 250. In some embodiments, each of the battery packs 252, 254, 256, and 258 is configured to calculate its own maximum steady state current value and communicate this calculated value on the communication bus 530. The master battery pack 252, in turn, is configured to sum these calculated maximum steady state current values received from the other packs 254, 256, and 258 along with the maximum steady state current value that the master battery pack 252 calculated for itself. The stun of these calculated values may be provided by the master battery pack 252 to the vehicle control module 90 as the maximum steady state current value for the battery packs of the power source 250.
With reference to
The battery controller 600 may use the minimum cell voltage, state of charge, and internal temperature for the pack in one or more lookup tables and state machines (of the battery controller 600) to determine the maximum steady state current value for the pack.
As one example, when the minimum cell voltage of the pack is above a voltage threshold, the state of charge is above a charge threshold, and the internal pack temperature is below a temperature threshold, the battery controller 600 may output a default maximum steady state current value (Imax_default). However, the battery controller 600 may output a reduced maximum steady state current value (e.g., 50%, 60%, 75% of Imax_default) if any of the following occur: (i) the minimum cell voltage of the pack drops below the voltage threshold. (ii) the state of charge drops below a charge threshold, or (iii) the internal pack temperature rises above a temperature threshold. Each characteristic may have multiple thresholds to cause the maximum steady state current value to be successively reduced or increased as the thresholds are crossed.
As can be seen from the above discussion, generally, the battery controller 600 reduces the maximum steady state current value for the pack based on one or more of the following: (i) the minimum cell voltage of the respective battery pack being below a voltage threshold, (ii) the pack state of charge of the respective battery pack being below a charge threshold, and (iii) the internal pack temperature of the respective battery pack being above a temperature threshold. Similarly, generally, the battery controller 600 increases the maximum steady state current value for the pack based on one or more of the following: (i) the minimum cell voltage of the respective battery pack being above a voltage threshold. (ii) the pack state of charge of the respective battery pack being above a charge threshold, and (iii) the internal pack temperature of the respective battery pack being below a temperature threshold.
Returning to the flow chart 650 of
In some embodiments, the mower electronic controller 500 divides the maximum aggregate drive motor current by a total number of the plurality of drive motors (e.g., by two, in the mower 10 that is illustrated) to determine the maximum chive current value for each of the one or more drive motors 45.
In some embodiments, the mower electronic controller 500 divides the maximum aggregate deck motor current by a total number of the plurality of deck motors (e.g., by three, in the mower 10 that is illustrated) to determine the maximum deck current value for each of the one or more deck motors 40.
In some embodiments, the vehicle control module 90 of the mower electronic controller 500 performs the calculation of the maximum aggregate drive motor current, the maximum aggregate deck motor current, the maximum drive current value for each of the one or more drive motors 45, and the maximum deck current value for each of the one or more deck motors 40. In some embodiments, the vehicle control module 90 provides the determined maximum drive current value for each of the one or more drive motors 45 to each of the drive motor controllers 550 and provides the determined maximum deck current value for each of the one or more deck motors 40 to each of the deck motor controllers 555.
In block 665, the mower electronic controller 500 controls the one or more drive motors 45 to maintain a respective motor current of the one or more drive motors 45 below the maximum drive current value. For example, each of the chive motor controllers 550 may determine motor current for a respective one of the drive motors 45 from respective current sensors 520. When one of the drive motor controllers 550 determines that the motor current for a drive motor 45 reaches the maximum drive current value, the drive motor controller 550 provides control signals to reduce the current of the drive motor 45. For example, to reduce the current of the chive motor 45, the drive motor controller 550 may reduce the duty cycle of a pulse width modulated (PWM) control signal being provided to the drive motor 45.
In block 670, the mower electronic controller 500 controls the one or more deck motors 40 to maintain a respective motor current of the one or more deck motors 40 below the maximum drive current value. For example, each of the deck motor controllers 555 may determine motor current for a respective one of the deck motors 40 from respective current sensors 524. When one of the deck motor controllers 555 determines that the motor current for a deck motor 40 reaches the maximum drive current value, the deck motor controller 555 provides control signals to reduce the current of the deck motor 40. For example, to reduce the current of the deck motor 40, the deck motor controller 555 may reduce the duty cycle of a pulse width modulated (PWM) control signal being provided to the deck motor 40.
In some embodiments, each deck motor 40 and drive motor 45 may be a brushless motor with a permanent magnet rotor and with stator coils selective energized with power from the power source 250 (i.e., the battery packs) by a switch bridge. The switch bridge may include one or more power switching elements, such as field effect transistors (FETs), that are selectively activated and deactivated by PWM signals provided by the associated motor controller 550 or 555. By increasing the duty cycle of the PWM signals, the stator coils are energized for longer periods, generally increasing the current drawn by the motor, the motor torque, and/or the motor speed. By decreasing the duty cycle of the PWM signals, the stator coils are energized for shorter periods, generally decreasing the current drawn by the motor, the motor torque, and/or the motor speed. In some embodiments, one or more of the deck motors 40 and drive motors 45 are brushed motors, which may also be controlled based on a PWM signal (from the motor controller 550 or 555) driving a power switching element connected in series with each respective brushed motor.
In some embodiments, the deck motor 40 and the drive motor 45 may also operate as generators and provide regenerative current back to the power source 250 (i.e., to charge one or more of the battery packs 252, 254, 256, and 258). For example, to brake the deck motor 40 or the drive motor 45, the one or more power switching elements may be selectively activated and deactivated such that induced current in the stator coils of the motors 40 and 45 caused by the rotating rotor magnets of the motor 40 or motor 45 is directed back towards the power source 250. In such examples, the maximum drive current value and maximum deck current value may be used by the respective deck and drive motor controllers 555, 550 to limit the regenerative current provided back to the power source 250. For example, to limit the regenerative current provided back to the power source 250, the deck and drive motor controllers 555, 550 may respectively reduce the PWM duty cycle for the power switching elements when regenerative current from the one or more of the motors 40, 45 reaches their respective maximum current values. Accordingly, in some embodiments, in addition to or instead of steps 665 and 670, one or more of the drive motor controllers 550 is configured to provide regenerative current from the respective drive motors 45 to the power source 250 while maintaining the regenerative current below the maximum drive current value, and one or more of the deck motor controller 555 is configured to provide regenerative current from the respective deck motors 40 to the power source 250 while maintaining the regenerative current below the maximum deck current value.
In some embodiments, a maximum deck charge current and maximum drive charge current value are determined separately from the maximum drive current value and maximum deck current value. In these embodiments, the maximum deck charge current and maximum drive charge current value are used to limit the regenerative current, rather than using the maximum drive and deck current values to limit the regenerative current. In these embodiments, a similar process as indicated in steps 655 and 660 may be used to determine the maximum deck and drive charge current values. For example, the vehicle control module 90 may determine a maximum steady state charge current value using a similar process as in step 655, where the vehicle control module 90 receives the maximum steady state charge current value from the master battery pack 252 of the power source 250. Further, the vehicle control module 90 may determine the maximum deck and drive charge current values based on the maximum steady state charge current value, using a similar apportionment scheme as described with respect to step 660.
PI Control LoopWith reference to
The integral term branch includes an integral coefficient Ki 735. The error signal is multiplied by the integral coefficient Ki 735 and the resulting output is provided to the integrator 740. The integrator 740 integrates the output from the integral coefficient Ki 735, and the resulting output is provided to the summation block 725. The summation block 725 sums the outputs from the proportional term branch and the integral term branch and provides the sum to the control block 745. The control block 745 translates the output to a PWM duty cycle value and provides the PWM duty cycle value to the drive motor 45 to control the drive motor 45. The drive motor 45 may then be controlled in accordance with the PWM duty cycle value as previously described.
Although the values illustrated in the PI control loop 560 are labeled, such as with RPM, PWM, the actual values may be encoded version of such values and not have the particular units noted or shown. For example, the RPM speed sensor signal may be an analog signal between 0-5 volts that is proportional to an RPM value or may be a digitized version of the analog signal (e.g., in a 16-bit binary format).
In block 755, the mower electronic controller 500 determines a desired motor speed based on an output from the maneuvering control sensor 510. For example, as previously described, the maneuvering control sensor 510 may sense the angle of the associated maneuvering control arm 72a and provide an output to the mower electronic controller 500 indicative of the sensed angle. In some embodiments, the vehicle control module 90 may in turn translate the sensed angle to a desired motor speed (e.g., the desired motor speed 705 of
In block 760, the mower electronic controller 500 determines a sensed motor speed based on an output from the speed sensor 522 indicative of the motor speed of the left drive motor 45. For example, as previously described, the speed sensor 522 may be, for example, a rotary encoder, a Hall sensor configured to detect passing rotor magnets of the respective motors, or another sensor type. For example, in some embodiments, the speed sensor 522 outputs an analog or digital signal indicative of the rotations per minute (RPMs) of the left drive motor 45. The sensed motor speed is provided to the PI control loop 560 of the drive motor controller 550a.
In block 765, the mower electronic controller 500 determines a proportional term adjustment factor based on the sensed motor speed. For example, with reference to
Returning to
Additionally, as noted, the method 750 may be executed by the mower electronic controller 500 independently for each drive motor 45 of the mower 10. Accordingly, the left drive motor 45 may be controlled by the mower electronic controller 500 by the PI control loop 560 of the drive motor controller 550a simultaneously with the right drive motor 45 being controlled by the mower electronic controller 500 by the PI control loop 560 of the drive motor controller 550b.
Off-Board ChargerThe handle 830 is coupled to the battery compartment 834 adjacent the first end 818 of the frame 810. As illustrated in
Now with reference to
The off-board charger 800 may further include a handle support structure 848 coupled to the battery compartment 834 and an adjustment mechanism 860 that selectively restricts pivotable movement of the handle 830. In the illustrated embodiment, the adjustment mechanism 860 is a pin that extends between the handle support structure 848 and the battery compartment 834. In the transport position (
Now with reference to
Referring now to
With continued reference to
In other embodiments, the battery interface 920 may include more docking stations 922 (e.g., five, six, etc.) or fewer docking stations 922 (e.g., one, two, three, or four). It should be appreciated that the battery interface 920 of the off-board charger 800 is similar to the battery interface 120 described above.
Now with reference to
In some embodiments, a cable harness is provided to connect the chargers 930 and 934 to the base 950. The cable harness may include power and ground cables as well as one or more communication lines (collectively referred to as a communication cable). The cable harness may further have a first (bus bar-side) connection end including first ends of the power, ground, and communication cables and a second (charger-side) connection end including second ends of the power, ground, and communication cables. The frame 20 may include first power and ground studs (not shown) in the charger compartment 838 providing a connection point between the power lines 952 and 954 and the cable harness. More particularly, the power lines 952 and 954 are respectively connected to the first power and ground studs, and the first ends of the power and ground cables of the cable harness are also respectively coupled to the first power and ground studs. Additionally, the first end of the communication cable of the cable harness may be coupled to the connector 956. Turning to the second end of the cable harness, the second ends of the power and ground cables may be coupled to second power and ground studs of the frame 20 that are located closer to the chargers 930 and 934. The frame 20 may further include first and second charging ports (see, e.g., charging ports 224, 228 shown in
With reference to
Each charger 930, 934 includes a charging switching network 1000, a rectifier 1002, and a charger controller 1005. The charger controller 1005 includes an electronic processor 1010 and a memory 1015 that stores instructions that are executed by the electronic processor 1010 to implement the functionality of the charger controller 1005 described herein.
The off-board charger 800 is coupled to an external power source 1020, which may be an alternative current (AC) power utility grid, an AC engine-generator, an AC inverter that inverts DC power from solar panels, batteries, or another DC source to AC power, or another source. The external power source 1020 may be, for example, a 120 V, 60 Hz AC source or a 220 V, 50 Hz AC source. Each charger 930, 934 is coupled to the external power source 1020 via an independent connection. More particularly, the first charger 930 is coupled to the external power source 1020 via a first power cable 1025a that connects the first power input connector 938 of the charger to a first outlet 1029a of the external power source 1020. The second charger 934 is coupled to the external power source 1020 via a second power cable 1025b that connects the second power input connector 942 of the charger to a second outlet 1029b of the external power source 1020.
In some embodiments, the first outlet 1029a and the second outlet 1029b are wall outlets (e.g., in a residential or commercial building or garage) that are each on a separate circuit of the external power source 1020. For example, the external power source 1020 may include an electrical panel coupled to the utility grid to receive power and distributing power via (i) a first circuit branch having a first current limit (e.g., 15 or 20 Amps) and being associated with a first circuit breaker and (ii) a second circuit branch having a second current limit (e.g., 15 or 20 Amps) and being associated with a second circuit breaker. The first outlet 1029a may be coupled to the first circuit branch and the second outlet 1029b may be coupled to the second circuit branch. Accordingly, the overall current that the charger 800 may draw from the external power source 1020 without tripping a circuit breaker may be larger (e.g., at 30 or 40 Amps) than if a single connection was provided to the external power source 1020 for both chargers 930 and 934. Additionally, because each charger 930, 934 is connected to an independent circuit, even if one circuit breaker trips for one of the outlets 1029a or 1029b, the other outlet may still be providing power and the charger 800 may be able to continue to charge.
The charger 800 further includes connector circuitry 1030 with a lid sensor 1035. The battery compartment 834 includes a bank of one or more batteries (e.g., the battery packs 852, 854, 856, 858), one of which may be identified as a master battery pack 252 and the remaining ones of which may be identified as a plurality of slave battery packs 254, 256, 258 (e.g., three in the illustrated embodiment). In other embodiments, the power source 250 may include more battery packs (e.g., five, six, seven, etc.) or fewer battery packs (e.g., two, three, one). The one or more battery packs of the battery compartment 834 (e.g., battery packs 252, 254, 256, and 258) are coupled to the one or more chargers 930, 934 by the connector circuitry 1030 and a power and communication bus 1040.
Each rectifier 1002 is configured to receive and convert AC power from the external power source 1020 to direct current (DC) power for output to the charging switching network 1000 of the same charger. The rectifier 1002 may be passive or active, and, in some embodiments, includes additional power conditioning components (e.g., one or more filters, DC-to-DC boost or buck converters, and the like). Each charger controller 1005 is configured to control the charging switching network 1000 (of the same charger) to selectively supply charging current to the one or more battery packs of the battery compartment 834 via the positive and negative lines of the bus 1040. For example, in some embodiments, each charging switching network 1000 includes one or more power switching elements (e.g., field effect transistors) that may be selectively activated by a control signal from the charger controller 1005 to enable DC power received from the associated rectifier 1002 to flow through positive and negative terminals on the bus 1040 to the one or more battery packs of the battery compartment 834.
In some embodiments, a similar technique as described above with the mower 10 is implemented to determine which battery pack 252, 254, 256, 258 is the master battery pack 252. For example, an identification number is assigned to each battery pack 252, 254, 256, 258 (e.g., one, two, three, four, etc.), and the battery pack 252, 254, 256, 258 with the lowest identification number is selected as the master battery pack 252 and the remaining battery packs are slave battery packs 254, 256, 258. As previous described with respect to the mower 10, the battery packs themselves may communicate amongst one another to determine which of the battery packs has the lowest identification number and, therefore, is the designated master battery pack. If the master battery pack 252 is removed from the battery interface, the battery packs may communicate and automatically reassign the slave battery pack 254, 256, 258 with the lowest identification number to be the master battery pack 252. Similarly, if an additional battery pack is attached to the battery interface 120, the battery packs may communicate and automatically assign the additional battery pack to be the master battery pack 252 when the newly added battery pack has the lowest identification number, and otherwise identify the newly added battery pack as a slave battery pack.
Additionally, in some embodiments, a similar technique as described above with the mower 10 is used to implement a priority charging method for the battery pack 252, 254, 256, 258. For example, the master battery pack 252 communicates with the first and second chargers 930, 934 and the slave battery packs 254, 256, 258 to determine the priority charging method. The master battery pack 252 may communicate with the first and second chargers or the slave battery packs themselves to request charging of a single battery pack (e.g., for sequential charging) or a plurality of battery packs (e.g., two, three, four, etc.) in parallel.
More specifically, each of the first and second chargers 930, 934 are coupled to charger receptacles 1050 of the off-board charger 800. In particular, a charger plug 1055 of each of the first and second chargers 930, 934 is coupled to respective charger receptacles 1050. The charger plug 1055 and charger receptacle 1050 connect positive and negative terminals of the first and second chargers 930, 934 to positive and negative terminals of the battery pack 252, respectively. Additionally, the charger plug 1055 and charger receptacle 1050 connect communication bus terminals (e.g., CAN-H and CAN-L terminals) of the first and second chargers 930, 934 to communication bus terminals of the battery pack 252. Additionally, each of the charger plugs 1055 includes a jumper 1060 that connects two terminals of the respective charger receptacle 1050.
The safety circuit 1057 includes conductive lines (e.g., wires, traces on a circuit board, etc.) between a wake terminal of the battery pack 252, a pack out terminal, and a safety terminal of the battery pack 252, as well as the lid sensor 1035 and the jumpers 1060 of the one or more charger plugs 1055 that may be present. In some instances, the lines connected to the wake terminal, pack out terminal, and safety terminal of the safety circuit 1057 may also be considered part of the bus 1040.
In some embodiments, the positive terminal, negative terminal, CAN-H terminal, CAN-L terminal, wake terminal, pack out terminal, and safety terminal illustrated in
The lid sensor 1035 of
In block 1115, the battery controller 600 receives the output signal from the safety circuit 1057 as a wake signal via the wake terminal. For example, as illustrated in
In block 1120, the battery controller 600 receives a safety signal from the lid sensor 1035 via the safety terminal of the battery pack 252. The safety signal is indicative of whether the lid 904 for the battery compartment 834 is closed. For example, the lid sensor 1035 may include a switch (as illustrated in
In block 1125, the battery controller 600 enables charging of the battery pack 252 in response to receipt of the wake signal and the safety signal. For example, in response to receiving the wake signal and the safety signal, the battery controller 600 first awakens from a standby mode into a normal operation mode. In some embodiments, the standby mode is a low power mode in which the controller 600 consumes less power with reduced functionality and in which the battery pack 252 may not be charged or discharged. In the normal operation mode, the controller 600 returns to normal functionality and power consumption, and the battery pack 252 may be charged (when coupled to the charger 800) or may be discharged (e.g., when coupled to the mower 10). More particularly, once awakened, to enable charging of the battery pack 252, the battery controller 600 is configured to enable one or more charge switches of the charge/discharge switches 635 (see
In some embodiments, the battery pack 252 provides feedback to a user upon receipt of the wake signal and the safety signal. For example, the battery pack 252 illuminates a light source (e.g., a light emitting diode (LED)) on a top surface of the battery pack 252 or generated an audible beep. Accordingly, a user can readily determine whether a battery pack has been properly inserted into the off-board battery charger 800 (or mower 10).
In some embodiments, the battery controller 600 includes other preconditions before enabling charging of the battery pack 252 in addition to receiving the wake signal and the safety signal. For example, as another precondition to enabling charging, the battery controller 600 may await a communication from one or more battery packs (e.g., battery packs 254, 256, and 258) or from one or more of the chargers 930, 934 over the communications lines (CAN-H and CAN-L) of the bus 1040. The battery controller 600 may also implement one or more of the priority charging schemes noted above with respect to charging battery packs on the mower 10 and, accordingly, another precondition is that the battery pack 252 is selected for charging based on the applicable priority charging scheme.
In block 1130, after charging of the battery pack 252 is enabled, the battery pack 252 receives charge current from one or more of the chargers 930, 934 (also referred to as a charging circuit). For example, battery pack 252 may communicate a request for charging current over the communication lines (CAN-H and CAN-L) of the bus 1040 to the charger controller 1005 of each of the one or more chargers of the off-board charger 800. In response to the request, each of the charger controllers 1005 controls its associated charging switching network 1000 to provide charging current from the rectifier 1002 over the power lines of the bus 1040 to the battery pack 252.
While the method 1100 is described with respect to charging the battery pack 252, the method is similarly applicable to the other battery packs that may be inserted into the battery compartment (e.g., the battery packs 254, 256, and 258). For example, in
Although
Further, in some embodiments when the mower 10 implements the method 1100, the method further includes enabling discharging of the battery pack, by the battery controller 600, in response to receipt of the wake signal and the safety signal. For example, once awakened, to disable charging of the battery pack 252, the battery controller 600 is configured to enable one or more discharge switches of the charge/discharge switches 635 (see
In block 1205, the mower electronic controller 500 operates in a calibration mode in response to a request received via a user interface (e.g., the system interface 74) of the mower 10. For example, on the user display 78 may be a touch screen that includes a mode select button (soft key) 1207 (see 41A). When depressed or touched, the mode select button 1207 provides a request to the mower electronic controller 500 to enter the calibration mode. In some embodiments, the mode select button 1207 is provided as an electro-mechanical push button (hard key) on the user interface (e.g., near or on a housing of the user display 78).
In block 1210, while in the calibration mode, the mower electronic controller 500 inhibits driving of at least one drive motor (e.g., the drive motors 45). For example, while in the calibration mode, even though the control arms 72a or 72b may be pushed forward or pulled back, the vehicle control module 90 will not generate control signals to the motor controllers 505 to drive motors 45 so that the mower 10 will not be controlled to move. Additionally, a parking brake of the mower 10 may be actuated to prevent movement of the mower 10 while in the calibration mode.
In block 1215, while in the calibration mode, the mower electronic controller 500 identifies a neutral set parameter based on a first output value from the maneuvering control sensor 510 (a position sensor, see
In some embodiments, in block 1215, before identifying the neutral set parameter, the mower electronic controller 500 is configured to control the display 78 of the mower 10 to provide a first prompt on the display 78 to instruct the operator of the mower 10 to release the control arm 72a into the neutral position. For example, with reference to
In some embodiments, in block 1215, to identify the first output value as the neutral set parameter, the mower electronic controller 500 is configured to average output values from the maneuvering control sensor 510 over a period while the left control arm 72a is in the neutral position. For example, the period may be five seconds, or another similar time period. The determined average output value is then assigned as the neutral set parameter.
In block 1220 and with additional reference to
In some embodiments, as seen in
In some embodiments, in block 1220, to identify the second output value as the forward set parameter, the mower electronic controller 500 is configured to detect the output value from the position sensor that has the greatest difference from the neutral set parameter while the control arm 72a is in the forward range (e.g., over a period, such as five seconds, or until the control arm 72a is released and returns to the neutral position). This output value with the greatest difference is then identified as the forward set parameter. In some embodiments, identifying this output value with the greatest difference as the forward set parameter is in response to the electronic controller also determining that this output value exceeds a minimum forward threshold value. For example, when the output value does not exceed the minimum forward threshold value, the output value is not identified as the forward set parameter, and the operator may again be provided the second prompt 1221 and the electronic controller may restart execution of the block 1220. In some embodiments, the minimum forward threshold value is used, for example, to ensure a minimum range of motion of the control arm 72a to enable the operator to control the drive motor 45 over a desired range of speeds with desired precision. In some embodiments, the minimum forward threshold is 10 degrees, at least 10 degrees, or another similar angle.
In block 1225 and with additional reference to
In some embodiments, in block 1225, before identifying the reverse set parameter, the mower electronic controller 500 is configured to control the display 78 of the mower 10 to provide a third prompt on the display 78 to instruct the operator of the mower 10 to pull the control arm 72a into the reverse position. For example, with reference to
In some embodiments, in block 1225, to identify the third output value as the reverse set parameter, the mower electronic controller 500 is configured to detect the output value from the position sensor that has the greatest difference from the neutral set parameter while the control arm 72a is in the reverse range (e.g., over a period, such as five seconds, or until the control arm 72a is released and returns to the neutral position). This output value with the greatest difference is then identified as the reverse set parameter. In some embodiments, identifying this output value with the greatest difference as the reverse set parameter is in response to the electronic controller 500 also determining that this output value exceeds a minimum reverse threshold value. For example, when the output value does not exceed the minimum reverse threshold value, the output value is not identified as the reverse set parameter, and the operator may again be provided the second prompt 1226 and the electronic controller 500 may restart execution of the block 1225. In some embodiments, the minimum reverse threshold value is used, for example, to ensure a minimum range of motion of the control arm 72a to enable the operator to control the drive motor 45 over a desired range of speeds with desired precision. In some embodiments, the minimum reverse threshold is less than the minimum forward threshold. For example, the minimum reverse threshold may be 9 degrees, at least 9 degrees, or another similar angle.
As illustrated in
In some embodiments, blocks 1215, 1220, and 1225 are repeated for the right control arm 72b to identify a second neutral set parameter, a second forward set parameter, and a second reverse set parameter for the right control arm 72b.
In
In block 1235, while operating in the drive mode, the mower electronic controller 500 determines an angular position of the left control arm 72a indicated by the maneuvering control sensor 510. For example, the maneuvering control sensor 510 senses the angular position of the left control arm 72a and, using the position map, generates an output value to the controller 500 that is indicative of the sensed angular position.
In block 1240, while operating in the drive mode, the mower electronic controller 500 controls the (left) drive motor 45 in accordance with the angular position of the left control arm 72a indicated by the maneuvering control sensor 510, the neutral set parameter, the forward set parameter, and the reverse set parameter. For example, when the angular position of the left control arm 72a is indicated to be at the neutral set parameter, the mower electronic controller 500 does not drive the drive motor 45. For example, a duty cycle of 0% is set by the drive motor controller 550a by the vehicle control module 90. When the angular position of the left control arm 72a is indicated to be at the forward set parameter, the mower electronic controller 500 drives the drive motor 45 at a maximum level in the forward direction. For example, the vehicle control module 90 may provide a control signal to the motor controller 550a and, in response, the motor controller 550a generates PWM control signals to the drive motor 45 forward and having a duty cycle of 100%. When the angular position of the left control arm 72a is indicated to be at the reverse set parameter, the mower electronic controller 500 drives the drive motor 45 at a maximum level in reverse. For example, the vehicle control module 90 may provide a control signal to the motor controller 550a and, in response, the motor controller 550a generates PWM control signals to the drive motor 45 in reverse and having a duty cycle of 100%. Additionally, when the angular position of the left control arm 72a is indicated to be at an angle between the forward set parameter and the neutral set parameter, the mower electronic controller 500 drives the drive motor 45 forward and at a speed proportional to the angle within the range of angles between the neutral set parameter and the forward set parameter. For example, when the range of angles between the neutral set parameter and the forward set parameter is 15 degrees, and the control arm 72a is at a midpoint in the range (i.e., 7.5 degrees), the PWM duty cycle may be 50%. Similarly, when the angular position of the left control arm 72a is indicated to be at an angle between the reverse set parameter and the neutral set parameter, the mower electronic controller 500 drives the drive motor 45 in reverse and at a speed proportional to the angle within the range of angles between the neutral set parameter and the reverse set parameter.
In some embodiments, in addition to the neutral set parameter, forward set parameter, and reverse set parameter, a deadband is determined for each parameter. The deadband provides a range of values for each respective parameter where, if the control arm 72a is determined to be in a deadband of a parameter, the mower electronic controller 500 controls the drive motor 45 as if the control arm 7a was at the particular parameter. For example, in some embodiments of the method 1200, while in the calibration mode, the mower electronic controller 500 determines one or more of: a neutral deadband based on the neutral set parameter, a maximum forward deadband based on the forward set parameter, and a maximum reverse deadband based on the reverse set parameter. For example, the mower electronic controller 500 may determine the neutral deadband by adding and subtracting a deadband value to the neutral set parameter (e.g., +/−3 degrees, +/−5 degrees, or +/−7 degrees). Similarly, the mower electronic controller 500 may determine the maximum forward and reverse deadband by adding and subtracting a deadband value to the forward and reverse set parameter, respectively (e.g., +/−3 degrees, +/−5 degrees, or +/−7 degrees). In some embodiments, the maximum forward and maximum reverse deadbands are each greater than the neutral deadband. When the mower electronic controller 500 is in the chive mode, the mower electronic controller 500 further controls the drive motor 45 in accordance with the angular position of the control arm indicated by the position sensor, the neutral deadband, the maximum forward deadband, and the maximum reverse deadband. Such control is similar to the control that was described above for block 1240, except that the deadbands are used in place of the specific neutral, forward set parameter, and reverse set parameter.
In some embodiments, while operating in the drive mode, the mower electronic controller 500 also executes block 1235 and 1240 for the right control arm 72b to drive the right drive motor 45 according to the angular position of the control arm 72b, the second neutral set parameter, the second forward set parameter, and the second reverse set parameter.
Returning to
In some embodiments, while in the calibration mode, the electronic controller 500 is further configured to update the position map of the maneuvering control sensor 510 to map a midpoint output value of the maneuvering control sensor 510 (e.g., 180 degrees/2048 count) to the neutral position of the control arm 72a. For example, if the neutral set parameter was determined to be 181 degrees (˜2059 count), the position map may be updated with a one degree offset such that the maneuvering control sensor 510 will now output 180 degrees/2048 count when the control arm 72a is in the neutral position. Additionally, to accommodate this update, the electronic controller 500 updates the forward set parameter (and associated maximum forward deadband) based on an offset from the neutral set parameter and the midpoint output value, and updates the reverse set parameter (and associated maximum reverse deadband) based on the offset. For example, if the forward set parameter was previously 164 degrees, an offset of 1 degree would be added to result in the forward set parameter being 165 degrees. Further, the electronic controller 500 updates the neutral set parameter to be the midpoint output value (e.g., 180 degrees/2048 count) to accommodate the update.
The diagram 1260 provides a subsequent mapping for the control arm 72a with a revised forward set parameter 1268, a revised forward deadband 1270, and the neutral set parameter 1266. The subsequent mapping for the control arm 72a in the diagram 1260 may be generated using the calibration method 1200. The revised forward set parameter 1268 and the revised forward deadband 1270 are shifted such that the revised forward deadband 1270 is not reached until a greater angle of the control arm 72a is reached (i.e., the control arm 72a is pushed further forward) as compared with the diagram 1255 and the initial mapping, thus giving the user more fine tune drivability.
Thus, embodiments described herein provide, among other things, systems, methods, and devices related to electric vehicles, mowers, and chargers. Various features, advantages, and embodiments are set forth in the following claims.
Claims
1-64. (canceled)
65. An electric lawn mower, the electric lawn mower comprising:
- a frame;
- a drive wheel supporting the frame above a ground surface;
- a cutting deck coupled to the frame;
- a drive motor mounted to the frame and driving rotation of the drive wheel to move the electric lawn mower over the ground surface, and
- a deck motor mounted to the cutting deck and configured to drive rotation of a blade under the cutting deck to cut grass under the cutting deck;
- a plurality of battery packs supported by the frame and configured to provide electrical power to the drive motor and to the deck motor;
- an electronic controller coupled to the drive motor and to the deck motor, the electronic controller configured to:
- determine a maximum steady state current value for the plurality of battery packs;
- determine a maximum drive current value for the drive motor and a maximum deck current value for the deck motor based on the maximum steady state current value, a duty cycle of the drive motor, and a duty cycle of the deck motor;
- control the drive motor to maintain a motor current of the drive motor below the maximum drive current value; and
- control the deck motor to maintain a motor current of the deck motor below the maximum deck current value.
66. The electric lawn mower of claim 65, wherein
- the drive motor is a first drive motor of a plurality of drive motors mounted to the frame and the drive wheel is a first drive wheel of a plurality of drive wheels supporting the frame above a ground surface,
- each drive motor of the plurality of drive motors is associated with a respective drive wheel of the plurality of drive wheels to move the electric lawn mower over the ground surface,
- the deck motor is a first deck motor of a plurality of deck motors, and the blade is a first blade of a plurality of blades under the cutting deck, and
- each deck motor of the plurality of deck motors is configured to drive rotation of a respective blade of the plurality of blades to cut grass under the cutting deck.
67. The electric lawn mower of claim 66, wherein, to determine a maximum drive current value for the drive motor and a maximum deck current value for the deck motor based on the maximum steady state current value, a duty cycle of the drive motor, and a duty cycle of the deck motor, the motor is further configured to:
- calculate a maximum aggregate drive motor current for the plurality of drive motors and a maximum aggregate deck motor current for the plurality of deck motors based on the maximum steady state current value, a duty cycle of the drive motor, and a duty cycle of the deck motor,
- divide the maximum aggregate drive motor current by a total number of the plurality of drive motors to determine the maximum drive current value, and
- divide the maximum aggregate deck motor current by a total number of the plurality of deck motors to determine the maximum deck current value.
68. The electric lawn mower of claim 67, wherein
- the electronic controller includes a vehicle control module including a processor and memory, a drive controller for each of the plurality of drive motors, and a deck controller for each of the plurality of deck controllers,
- the vehicle control module is configured to determine and provide the maximum drive current value to each of the plurality of drive controllers and is configured to determine and provide the maximum deck current value to each of the plurality of deck controllers.
69. The electric lawn mower of claim 68, wherein
- each of the plurality of drive controllers is configured to control an associated drive motor to maintain motor current of the associated drive motor below the maximum drive current value, and
- each of the plurality of deck controllers is configured to control an associated deck motor to maintain motor current of the associated deck motor below the maximum drive current value.
70-74. (canceled)
75. A method of controlling power distribution in an electric lawn mower, the method comprising:
- determining, by an electronic controller, a maximum steady state current value for a plurality of battery packs supported by a frame of the electric lawn mower and configured to provide electrical power to a drive motor and to a deck motor, where the drive motor is mounted to the frame and configured to drive rotation of a drive wheel to move the electric lawn mower over a ground surface and where the deck motor is configured to drive rotation of a blade to cut grass under a cutting deck;
- determining, by the electronic controller, a maximum drive current value for the drive motor and a maximum deck current value for the deck motor based on the maximum steady state current value, a duty cycle of the drive motor, and a duty cycle of the deck motor;
- controlling, by the electronic controller, the drive motor to maintain a motor current of the drive motor below the maximum drive current value; and
- controlling, by the electronic controller, the deck motor to maintain a motor current of the deck motor below the maximum deck current value.
76. The method of claim 75, wherein the drive motor is a first drive motor of a plurality of drive motors mounted to the frame and the drive wheel is a first drive wheel of a plurality of drive wheels supporting the frame above a ground surface, and wherein the deck motor is a first deck motor of a plurality of deck motors, and the blade is a first blade of a plurality of blades under the cutting deck, the method further comprising
- driving, by each drive motor of the plurality of drive motors, a respective drive wheel of the plurality of drive wheels to move the electric lawn mower over the ground surface, and
- driving, by each deck motor of the plurality of deck motors, a respective blade of the plurality of blades to cut grass under the cutting deck.
77. The method of claim 76, wherein determining a maximum drive current value for the drive motor and a maximum deck current value for the deck motor based on the maximum steady state current value, the duty cycle of the drive motor, and the duty cycle of the deck motor includes:
- calculating a maximum aggregate drive motor current for the plurality of drive motors and a maximum aggregate deck motor current for the plurality of deck motors based on the maximum steady state current value, a duty cycle of the drive motor, and a duty cycle of the deck motor,
- dividing the maximum aggregate drive motor current by a total number of the plurality of drive motors to determine the maximum drive current value, and
- dividing the maximum aggregate deck motor current by a total number of the plurality of deck motors to determine the maximum deck current value.
78. The method of claim 77, wherein the electronic controller includes a vehicle control module including a processor and memory, a drive controller for each of the plurality of drive motors, and a deck controller for each of the plurality of deck controllers, the method further comprising:
- providing, by the vehicle control module, the maximum drive current value to each of the plurality of drive controllers; and
- providing, by the vehicle control module, the maximum deck current value to each of the plurality of deck controllers.
79. The method of claim 78, wherein
- controlling, by each of the plurality of drive controllers, an associated drive motor to maintain motor current of the associated drive motor below the maximum drive current value, and
- controlling, by each of the plurality of deck controllers, an associated deck motor to maintain motor current of the associated deck motor below the maximum drive current value.
80-154. (canceled)
Type: Application
Filed: May 20, 2022
Publication Date: Jun 15, 2023
Inventors: Evin Ballantyne (Waterloo), Andrew Flemming (Waterloo), Muhammad Ikhlas (Waterloo)
Application Number: 17/750,063
