Abstract: A robotic mower inductive charging station includes a plurality of transmitter coils mounted on a horizontal base structure in a pattern for inductive charging of a robotic mower that may enter and approach the charging station from any direction. The horizontal base structure may have a plurality of slots, perforations or holes covering at least about 50% of the base structure's surface area.

Abstract: An electric lawn tractor power management system and method including a power management switch having a normal mode setting and a power management mode setting. In response to actuation of the power management switch to the power management mode setting, a blade motor controller commands a blade motor to rotate at a power management speed lower than a normal speed, and a traction drive motor controller commands a traction drive motor to rotate up to a maximum power management speed lower than a normal maximum speed. At least one persistence counter notifies the controllers if excess loading conditions exist on the blade motor or traction drive motor. The controllers change the speeds and/or response of the blade motor and traction drive motor in response to the excess loading conditions.

Abstract: A robotic mower inductive charging station includes a plurality of transmitter coils mounted on a horizontal base structure in a pattern for inductive charging of a robotic mower that may enter and approach the charging station from any direction. The horizontal base structure may have a plurality of slots, perforations or holes covering at least about 50% of the base structure's surface area.

Abstract: An electric lawn tractor roll away prevention system includes a brushless DC electric motor powering a traction drive wheel on the electric lawn tractor. The motor is connected to phase wires and provides a back EMF voltage on the phase wires if the electric lawn tractor rolls and turns the traction drive wheel without electric power from the motor. A three phase inverter rectifies the back EMF voltage, turns on the traction controller if the rectified voltage reaches a pre-specified threshold, and applies a voltage to the phase wires to reduce the speed of the electric lawn tractor by regenerative braking.

Abstract: A first motor controller generates commanded speeds of a first rotor of a first electric motor for a first time interval and a second time interval. A first speed monitor detects observed speeds of the first rotor for the time intervals. A first ratio is determined based on a relationship between respective commanded speeds and corresponding observed speeds for the first time interval and the second time interval. A first data processor increments a persistence counter for the first motor if the first ratio increases or changes during the time intervals. A first motor deceleration is estimated if the persistence counter exceeds a stall limit count. A target rotor speed of a second motor is adjusted based on the estimated first motor rate of change to track the first motor rate of change (or first rotor speed) if the persistence counter exceeds the stall limit count.

Abstract: An electric lawn tractor power management system and method including a power management switch having a normal mode setting and a power management mode setting. In response to actuation of the power management switch to the power management mode setting, a blade motor controller commands a blade motor to rotate at a power management speed lower than a normal speed, and a traction drive motor controller commands a traction drive motor to rotate up to a maximum power management speed lower than a normal maximum speed. At least one persistence counter notifies the controllers if excess loading conditions exist on the blade motor or traction drive motor. The controllers change the speeds and/or response of the blade motor and traction drive motor in response to the excess loading conditions.

Abstract: An electric lawn tractor roll away prevention system includes a brushless DC electric motor powering a traction drive wheel on the electric lawn tractor. The motor is connected to phase wires and provides a back EMF voltage on the phase wires if the electric lawn tractor roils and turns the traction drive wheel without electric power from the motor. A three phase inverter rectifies the back EMF voltage, turns on the traction controller if the rectified voltage reaches a pre-specified threshold, and applies a voltage to the phase wires to reduce the speed of the electric lawn tractor by regenerative braking.

Abstract: A first motor controller generates commanded speeds of a first rotor of a first electric motor for a first time interval and a second time interval. A first speed monitor detects observed speeds of the first rotor for the time intervals. A first ratio is determined based on a relationship between respective commanded speeds and corresponding observed speeds for the first time interval and the second time interval. A first data processor increments a persistence counter for the first motor if the first ratio increases or changes during the time intervals. A first motor deceleration is estimated if the persistence counter exceeds a stall limit count. A target rotor speed of a second motor is adjusted based on the estimated first motor rate of change to track the first motor rate of change (or first rotor speed) if the persistence counter exceeds the stall limit count.

Abstract: An aerator having a flexible frame for use on sloped or undulating ground surfaces of golf courses and other turf. The aerator includes a pair of frame sections linked together at a horizontal pivot axis, one of the frame section supporting a coring head. A ground sensor is pivotably attached to one of the frame sections so that the ground sensor may pivot in response to changes in ground slope and provide output relating to the magnitude of the change. Based on the output, a flex frame actuator pivots the pair of frame sections with respect to each other.

Abstract: An aerator having a flexible frame for use on sloped or undulating ground surfaces of golf courses and other turf. The aerator includes a pair of frame sections linked together at a horizontal pivot axis, one of the frame section supporting a coring head. A ground sensor is pivotably attached to one of the frame sections so that the ground sensor may pivot in response to changes in ground slope and provide output relating to the magnitude of the change. Based on the output, a flex frame actuator pivots the pair of frame sections with respect to each other.

Abstract: An aerator with a hole spacing control system is disclosed. The aerator has a traction drive with at least a pair of driven wheels and a single steered wheel. A vehicle control unit provides commands to the traction drive to move the aerator at a specified ground speed. An operator-adjustable hole spacing actuator may be moved to a plurality of hole spacing settings. The hole spacing actuator is electrically connected to the vehicle control unit. The vehicle control unit includes logic to vary the commands to the traction drive based on the hole spacing settings from the actuator. An engine speed sensor and/or coring head speed sensor also may be electrically connected to the vehicle control unit, and the vehicle control unit commands being also based on inputs from those speed sensors.

Abstract: A system and method for adjusting the frequency of clip for a reel mower cutting unit includes an operator interface outputting a voltage corresponding to a frequency of clip setting, and a reel motor controller calculating a travel speed of the reel mower cutting unit based on a voltage reading from a voltage bus and a scale factor applied to the voltage reading, and calculating a required reel speed based on the travel speed, the voltage corresponding to the frequency of clip setting, and the number of cutting blades of the reel mower cutting unit.

Abstract: An aerator with a hole spacing control system is disclosed. The aerator has a traction drive with at least a pair of driven wheels and a single steered wheel. A vehicle control unit provides commands to the traction drive to move the aerator at a specified ground speed. An operator-adjustable hole spacing actuator may be moved to a plurality of hole spacing settings. The hole spacing actuator is electrically connected to the vehicle control unit. The vehicle control unit includes logic to vary the commands to the traction drive based on the hole spacing settings from the actuator. An engine speed sensor and/or coring head speed sensor also may be electrically connected to the vehicle control unit, and the vehicle control unit commands being also based on inputs from those speed sensors.

Abstract: A system and method for adjusting the frequency of clip for a reel mower cutting unit is provided. The system includes an operator interface outputting a voltage corresponding to a frequency of clip setting, and a reel motor controller calculating a travel speed of the reel mower cutting unit based on a voltage reading from a voltage bus and a scale factor applied to the voltage reading, and calculating a required reel speed based on the travel speed, the voltage corresponding to the frequency of clip setting, and at least one numerical constant specific to the reel mower cutting unit.