Abstract: Pedal mounted sensors are useful in motor vehicles for delivering an electrical signal correlative to the position of the accelerator pedal. The electrical signal is then used by an engine controller to regulate the amount of fuel supplied to the engine. Some pedal mounted sensors deliver analog signals which are subject to fault conditions which an engine controller can not distinguish from valid operating conditions. Remotely mounted sensors are difficult to install and repair. The subject invention is directed to pedal mounted sensors which have a potentiometer and circuit board hermetically sealed and mounted on a pedal for delivering pulse-width-modulated signal having a duty factor responsive to the pedal position.

Abstract: Motor control systems are commonly associated with motors found on electric industrial vehicles, such as lift trucks. Advantageously, the control of such motors should be optimized such that current is timely supplied to the motors in conjunction with selection of the appropriate motor direction. The instant apparatus 10 includes a logic device 24 for receiving speed and direction demand signals from respective speed and direction selection devices 20,22. The logic device 24 responsively produces respective motor speed and direction command signals. A motor control device 26 receives the command signals and directs the electrical current from a power source 18 through the motor 12. A transducer device 38 senses the actual direction of electrical current flow through the motor 12 and produces responsive feedback signals. The logic device 24 produces at least one motor direction interrogation pulse in response to receiving the speed and direction demand signals and prior to delivering the motor command signals.

Abstract: A velocity reference system uses a Doppler shift between transmitted and received wave energy to determine the relative speed between the system and a surface or element. Other systems employing Doppler shifts for detecting velocity suffer from poor measurement accuracy. Cross talk between channels of systems having multiple transmitters and receivers produces measurement errors. Additionally, errant movement generates measurement errors since the sensors cannot distinguish such errant movement from forward velocity. Two sensing units directed towards one another, and preferably towards the same location on the surface, effectively eliminates random vehicle movement. Furthermore, transmitting different frequencies from the two sensing units reduces cross talk between the two channels. Vehicle applications require a system capable of minimizing errant movement and environmental noise.

Abstract: Motor control systems having solid-state components are commonly used on industrial vehicles such as lift trucks. Such solid-state components are easily damaged by excessive transient voltages. The subject invention includes a power supply for supplying direct current to a motor circuit, wherein the direct current has a nominal direct current voltage value and as associated transient voltage component. A pulse control circuit supplies current pulses from the power supply to a motor. A sensing device controllably produces a fault signal in response to the amplitude and frequency of occurrence of the transient voltage component exceeding a predetermined maximum value. An override circuit receives the fault signal and responsively modifies the current pulses delivered from the power supply to the associated motor.

Abstract: A system determines the surface profile of an object. Systems of this kind are used in industrial robots, such as automatic welders. The severe operating environment requires a vision system with noise immunity along with accuracy. A beam splitter enables the use of discrete optical detectors which eliminate many problems inherent with previously used detectors, such as diode arrays and TV cameras. Additionally, an automatic gain control alters the intensity of a generated optical beam in response to the reflectivity of the surface. These features increase the accuracy and noise immunity of an optical vision system for use in sever industrial applications.

Abstract: An apparatus for detecting obstacles in the path of a work vehicle, in which a transducer produces radiant energy, receives radiant energy reflected from an obstacle and produces an obstacle detected signal in response to receiving the reflected radiant energy. A rotatable reflector projects the radiant energy produced by the transducer radially outwardly from the work vehicle and directs the reflected radiant energy back to the transducer. An encoder produces an enable signal in response to predetermined positions of the rotatable reflector and is located along the same axis of rotation as the optical reflector. Zone control logic receives the obstacle detected signal and the enable signal and produces a vehicle control signal if both signals are present.

Abstract: Industrial vehicles incorporating obstacle detection systems are commonly employed in commercial applications. Advantageously, such collision avoidance systems should incorporate failure detection systems sufficient to make such systems fail-safe. The subject obstacle detection system includes one or more transducers 24,24' adapted to produce article detected signals in response to sensing an obstacle in front of the vehicle 12. Preferably the transducers 24,24' are pivotally mounted to the vehicle 12. The transducers 24,24' are adapted to produce the article detected signals at regular predetermined intervals, and a sensor failed signal is produced in response to the transducers 24,24' ceasing to produce the article detected signal at such regular intervals.

Abstract: Scanning devices are commonly utilized in conjunction with automatically guided welding systems in order to interpret the location and other characteristics associated with a groove to be welded. Many such systems utilize lasers as a source of radiant energy. The instant invention includes a sensing circuit for detecting radiant energy produced by the arc of a welding torch and producing first and second status signals in response to the respective absence and presence of the arc. A logic circuit produces a first power command signal in response to receiving the first status signal and a second power command signal in response to receiving the second status signal. A radiant energy emitting device controllably produces radiant energy having a first relatively low power level in response to receiving the first power command signal and a second relatively high power level in response to receiving the second power command signal.

Abstract: Automatic guided vehicles require an accurate method and apparatus for determining vehicle velocity. The subject apparatus is associated with a vehicle having at least one surface engaging idler wheel. A resolver produces a rotation angle rate signal having a value responsive to the angular rotation rate of the idler wheel. A resolver-to-digital converter receives the rotation rate angle signal and produces a rotation rate pulse signal. A clock substantially continuously produces clock pulse signals having a predetermined frequency. A counter receives the rotation rate pulse signal and the clock pulse signal and controllably produces a time signal corresponding to the number of clock pulses received over the duration of a predetermined portion of the rotation rate pulse signal. A logic device controllably receives the time signal and produces a vehicle velocity signal.

Abstract: A compound-motor speed control system for a battery-powered vehicle (86) wherein the series winding (14) and the shunt winding (16) of the motor (12) are magnetically linked in energy transfer relation. A first current switch (18) is connected in series with the series winding (14) and the armature (15) and a second current switch (20) is connected in series with the shunt winding (16). A digitally-implemented speed control system (24) responds to the speed selection settings of an analog device (64) to operate the first switch intermittently while holding the second switch closed over a lower speed range, and to operate the second switch intermittently while holding the first switch closed over a higher speed range.

Abstract: Anti-spin control systems are useful, for example, in industrial off-road vehicles. It is desirable that such systems exhibit rapid response to adverse working conditions, and be capable of quickly applying braking forces to whichever driven wheel is rotating at a higher velocity at a given time. The instant invention includes an electrical circuit for producing first and second brake control signals having values responsive to a working condition wherein one of the vehicle wheels loses traction and rotates more rapidly than the other vehicle wheel. A first controllable valve receives the first brake control signal and responsively controllably engages a brake mechanism associated with the faster rotating wheel, while a second controllable valve receives the second brake control signal and responsively controllably moves a brake mechanism associated with the slower rotating wheel from a brake released position to a brake pre-engaged position.

Abstract: An electrical drive circuit for a variable-speed switched reluctance motor having a bifilar winding is provided. First, second, and third thyristor switches (5,7,10) each having respective firing circuits (6,8,11) are associated with the motor. A commutation capacitor device (9) is associated with one of the thyristor switches (5,7,10). A sensing means (33) determines the direction of current flow through the commutation capacitor device (9), and a control system (20) prevents the first and third thyristor switches (5,10) from conducting when the second thyristor switch (7) is conducting and prevents the first and second thyristor switches (5,7) from conducting when the third thyristor switch (10) is conducting.

Abstract: Utility charges associated with peak electrical power demands constitute an increasing portion of utility bills associated with large commercial consumers of electricity. The instant invention provides an apparatus for reducing the peak electrical demand of a predetermined user operational unit from an electrical power distribution network by controllably operating at least one secondary electrical generator associated with the operational unit in parallel with the utility power distribution network. The secondary electrical generator includes a switch for connecting the generator in parallel with the utility network in response to receiving a transfer command signal. A transducer senses the actual peak power demand of the operational unit from the utility network and produces a demand signal having a value responsive to the sensed actual peak power demand. A memory element controllably stores a plurality of control parameters including a demand setpoint value.

Abstract: Collision detection systems are commonly provided on automatic guided industrial vehicles. Such systems should be as reliable as possible and can advantageously utilize a fault detection apparatus. The subject apparatus provides a plurality of radiant energy emitting devices and receiving devices positioned along a vehicle at locations sufficient that an obstacle in a respective path of the vehicle interrupts the reception of radiant energy by respective ones of the receiving devices. Interruptable devices controllably connect a power supply to a brake control circuit in response to continuous reception of radiant energy by the respective receiving devices, and disconnect the power supply from the brake control circuit in response to any of the receiving devices failing to continue to receive radiant energy from the respective emitting device.

Abstract: A communication apparatus for controllably bidirectionally transferring information between a vehicle and a docking station advantageously utilizes pulsed radiant energy for effecting the information transfer. A first radiant energy emitting device and a first radiant energy detecting device is located on the vehicle and a second radiant energy emitting device and a second radiant energy detecting device is located on the docking station. A first frequency control device recieves electrical signals from the first radiant energy detecting device, produces pulse control signals having a nominal frequency which is variable within a predetermined frequency range, and controllably delivers the produced pulse control signals at the nominal frequency to the first radiant energy emitting device located on the vehicle.

Abstract: Motor control circuits having solid-state switching elements are commonly used on industrial vehicles such as lift trucks. A short circuit condition in the motor circuit can cause catastrophic failure of the semiconductor switching element. The instant invention detects such a short circuit condition and modifies the motor control signals supplied by a chopper circuit to a switching element. The apparatus includes a trigger circuit for receiving the motor control signals and sensing a voltage across the motor produced in response to electrical power delivered from a power supply.

Abstract: Seat switches for detecting the presence and absence of an occupant in the seat of a vehicle are commonly used on industrial and commercial vehicles. It is desirable that the control signal produced by such seat switches be responsive only to the presence and absence of the vehicle occupant, and be relatively simple, rugged, and inexpensive. The instant invention includes an emitting device for directing a source of coded radiant energy across a vehicle seat, and a detecting device for receiving radiant energy, including a portion of the coded radiant energy in response to the seat being vacant. The detecting device produces an electrical signal in response to the received radiant energy. An electrical circuit produces a control signal only in response to the detecting device receiving the coded radiant energy.

Abstract: Resolvers are in common use as angular position sensing devices. Such resolvers normally require difficult to generate sine-wave excitation signals, and extensive decoding circuitry for producing an output signal related to angular position. The subject apparatus utilizes a generator to produce a rectangular-wave timing signal. A logic circuit receives the timing signal and responsively produces first and second rectangular-wave excitation signals, which are delivered to respective stator coils of a resolver. A decoding circuit receives one of the excitation signals and the phase encoded signal magnetically induced in the rotor coil of the resolver, and produces an angular position signal having a duty cycle responsive to the phase difference between the received signals.

Abstract: Motor control circuits having fault protection devices are in commercial use today. Such devices typically include logic elements requiring a conditioned power supply, and are incapable of operation directly from the main motor power supply. The subject apparatus includes a timing circuit for monitoring the electrical conduction of a power switching element associated with an electrical motor. The apparatus produces a fault signal in response to the power switching element continuing to conduct for longer than a predetermined continuous period of time. A latch receives the fault signal and responsively produces a blocking signal. An interrupt circuit receives the blocking signal and responsively controllably blocks power from the motor power supply to the electrical motor. Each of the timing, latch, and interrupt circuits is adapted to operate directly from the motor power supply and independent of any intermediate logic power supplies or associated logic devices.

Abstract: Linear potentiometers are commonly used as position sensors on various mechanical devices. Such potentiometers are frequently subjected to extreme vibratory excitation, which is known to cause premature failure. The subject potentiometer includes a housing having interior walls defining a cavity. First and second guide slots are linearly disposed along the cavity walls parallel to the housing. A wiper block is positioned and is axially movable within the cavity. The wiper block includes first and second slide rails linearly disposed along the wiper block and extending outwardly from the wiper block at a location sufficient to project into respective ones of the guide slots. Each of the first and second slide rails has a plurality of tapered engaging portions positioned adjacent respective surfaces of the guide slots.