Abstract: A materials handling vehicle is provided comprising: a frame; wheels supported on the frame; a traction motor coupled to one of the wheels to effect rotation of the one wheel; a speed control element operable by an operator to define a speed control signal corresponding to a desired speed of the traction motor; a system associated with a steerable wheel to effect angular movement of the steerable wheel; and control apparatus coupled to the speed control element to receive the speed control signal, and coupled to the traction motor to generate a drive signal to the traction motor in response to the speed control signal to control the operation of the traction motor. The control apparatus may determine an acceleration value for the traction motor based on at least one of an angular position of the steerable wheel, a speed of the traction motor and a current position of the speed control element as defined by the speed control signal.

Abstract: A materials handling vehicle is provided comprising: a frame; wheels supported on the frame; a traction motor coupled to one of the wheels to effect rotation of the one wheel; a speed control element operable by an operator to define a speed control signal corresponding to a desired speed of the traction motor; a system associated with a steerable wheel to effect angular movement of the steerable wheel; and control apparatus coupled to the speed control element to receive the speed control signal, and coupled to the traction motor to generate a drive signal to the traction motor in response to the speed control signal to control the operation of the traction motor. The control apparatus may determine an acceleration value for the traction motor based on at least one of an angular position of the steerable wheel, a speed of the traction motor and a current position of the speed control element as defined by the speed control signal.

Abstract: A materials handling vehicle is provided comprising: a frame; wheels supported on the frame; a traction motor coupled to one of the wheels to effect rotation of the one wheel; a speed control element operable by an operator to define a speed control signal corresponding to a desired speed of the traction motor; a system associated with a steerable wheel to effect angular movement of the steerable wheel; and control apparatus coupled to the speed control element to receive the speed control signal, and coupled to the traction motor to generate a drive signal to the traction motor in response to the speed control signal to control the operation of the traction motor. The control apparatus may determine an acceleration value for the traction motor based on at least one of an angular position of the steerable wheel, a speed of the traction motor and a current position of the speed control element as defined by the speed control signal.

Abstract: A materials handling vehicle is provided comprising: a frame; wheels supported on the frame; a traction motor coupled to one of the wheels to effect rotation of the one wheel; a speed control element operable by an operator to define a speed control signal corresponding to a desired speed of the traction motor; a system associated with a steerable wheel to effect angular movement of the steerable wheel; and control apparatus coupled to the speed control element to receive the speed control signal, and coupled to the traction motor to generate a drive signal to the traction motor in response to the speed control signal to control the operation of the traction motor. The control apparatus may determine an acceleration value for the traction motor based on at least one of an angular position of the steerable wheel, a speed of the traction motor and a current position of the speed control element as defined by the speed control signal.

Abstract: A materials handling vehicle is provided comprising: a frame; wheels supported on the frame; a traction motor coupled to one of the wheels to effect rotation of the one wheel; a speed control element operable by an operator to define a speed control signal corresponding to a desired speed of the traction motor; a system associated with a steerable wheel to effect angular movement of the steerable wheel; and control apparatus coupled to the speed control element to receive the speed control signal, and coupled to the traction motor to generate a drive signal to the traction motor in response to the speed control signal to control the operation of the traction motor. The control apparatus may determine an acceleration value for the traction motor based on at least one of an angular position of the steerable wheel, a speed of the traction motor and a current position of the speed control element as defined by the speed control signal.

Abstract: A materials handling vehicle is provided comprising a frame comprising an operator's compartment, wheels supported on the frame, at least one of the wheels being a steerable wheel, and a steer-by-wire system associated with the steerable wheel to effect angular movement of the steerable wheel. The vehicle further comprises a control apparatus.

Abstract: A materials handling vehicle is provided comprising: a frame comprising an operator's compartment; wheels supported on the frame, at least one of the wheels being a steerable wheel; a steer-by-wire system and control apparatus. The steer-by-wire system is associated with the steerable wheel to effect angular movement of the steerable wheel about a first axis.

Abstract: A method and apparatus for electronic commutation of a pulse width modulation (PWM) controlled motor involves temporarily increasing the frequency of one or more PWM drive signals applied to the motor upon the occurrence of an asynchronous commutation event.

Abstract: A method and apparatus for electronic commutation of a pulse width modulation (PWM) controlled motor involves temporarily increasing the frequency of one or more PWM drive signals applied to the motor upon the occurrence of an asynchronous commutation event.

Abstract: A materials handling vehicle is provided comprising: a frame comprising an operator's compartment; wheels supported on the frame, at least one of the wheels being a steerable wheel; a steer-by-wire system and control apparatus. The steer-by-wire system is associated with the steerable wheel to effect angular movement of the steerable wheel about a first axis.

Abstract: A materials handling vehicle is provided comprising: a frame; wheels supported on the frame; a traction motor coupled to one of the wheels to effect rotation of the one wheel; a speed control element operable by an operator to define a speed control signal corresponding to a desired speed of the traction motor; a system associated with a steerable wheel to effect angular movement of the steerable wheel; and control apparatus coupled to the speed control element to receive the speed control signal, and coupled to the traction motor to generate a drive signal to the traction motor in response to the speed control signal to control the operation of the traction motor. The control apparatus may determine an acceleration value for the traction motor based on at least one of an angular position of the steerable wheel, a speed of the traction motor and a current position of the speed control element as defined by the speed control signal.

Abstract: A materials handling vehicle is provided comprising a frame comprising an operator's compartment, wheels supported on the frame, at least one of the wheels being a steerable wheel, and a steer-by-wire system associated with the steerable wheel to effect angular movement of the steerable wheel. The vehicle further comprises a control apparatus.

Abstract: A method and apparatus for electronic commutation of a pulse width modulation (PWM) controlled motor involves temporarily increasing the frequency of one or more PWM drive signals applied to the motor upon the occurrence of an asynchronous commutation event.

Abstract: A method produces PWM voltage waveforms in a PWM motor controller of a three phase PM DC brushless motor, wherein the motor controller has first, second and third half H-bridge transistor pairs to generate the voltage waveforms to electronically commutate the motor. The first transistor pair is always assigned to the first phase for every commutation state requiring a voltage waveform from the first transistor pair. The second and third transistor pair are similarly assigned. The first method also includes always starting a voltage waveform generated by the first transistor pair substantially at the beginning of the PWM period when a commutation state requires a voltage waveform from the first transistor pair but delaying starting a voltage waveform generated by the second transistor pair by substantially ? of the PWM period and delaying starting a voltage waveform generated by the third transistor pair by substantially ? of the PWM period.

Abstract: A control system for operating a device. The control system comprises a plurality of command elements generating command signals and a control element having a plurality of control modes. Each control mode includes a transfer function output effective to operate the device in a predetermined manner and is selectable in accordance with the status of at least one of the command signals. The transfer function output of a nonselected control mode is made to substantially track the transfer function output of a selected control mode such that the transfer function output of the nonselected control mode is substantially similar in magnitude to the transfer function output of the selected mode when the control element selects the nonselected mode. A method employs the system.

Abstract: A method and apparatus for detecting winding errors in electric motor stators having a plurality of field windings is disclosed. The method involves the steps of applying a current source to at least one of the field windings to generate a magnetic field within the stator, measuring the polarity and strength of the field for each winding at preselected radial and angular positions about a circumference of the stator bore, and comparing the measured values to recorded values of radially and angularly corresponding measurements for a reference motor stator. Preferably, the current source is applied to each of the windings in succession. The apparatus includes a terminal block, switch, and power supply to connect a source of current to each field winding in succession to generate a magnetic field within the stator.