Abstract: A system and method for controlling the clutches in a vehicle powershift transmission. The control system includes a microprocessor which periodically executes an algorithm and which has a memory in which is stored a sequential set of time reference values and a sequential set of pressure values. The control system applies to each oncoming element a fill pressure pulse for fill periods which are unique for each element. The control system determines shift time values, subsequent to filling of the control elements, as a function of the fill period. The control system applies pressure signals to the control elements at times represented by the shift time values which are unique for each element. The control system determines, subsequent to a realignment time, realignment shift time values which are the same for all of the control elements.

Abstract: A control system for a vehicle powershift transmission includes a set of electrical connectors which in a normal mode, permit electrical power to be transmitted to microprocessor-controlled valve drivers for the transmission clutch control valves. These connectors may be swapped, in a limp-home mode, to permit power to be transmitted directly to the transmission clutch control valves. In both modes, a start-in-gear protection circuit including a pair of relays and switches coupled to the shift lever prevents the vehicle from being started up with a gear engaged. In the limp-home mode, a limp-home relay and a clutch disengaged switch prevents gear engagement until the operator has depressed and then released the clutch pedal, and the clutch pedal may be operated to modulate and control gear engagement.

Abstract: The hydraulically operated brake and clutch elements (controlled by proportional control valves) of a vehicle powershift transmission have fill pressures which are calibrated by a method wherein the output shaft of the transmission is disconnected from the vehicle drive shaft so that the transmission output shaft is free to rotate and certain ones of the plurality of the control elements other than the control element being calibrated are fully pressurized in order to prevent rotation of a part of the control element being calibrated. The engine is run at a predetermined speed and the pressure applied to the control element being calibrated is gradually increased while engine speed is monitored. When the monitored engine speed changes by predetermined amount, a value is saved corresponding to the calibration pressure. The transmission is automatically shifted to neutral if vehicle motion is sensed.

Abstract: A system for measuring the displacement of a workpiece from a reference coordinate system. Position information with respect to the various axes of the coordinate system is acquired by rotary resolver assemblies that measure the angular position of rotatable elements. Each resolver assembly includes a coarse and a fine resolver. Signals representative of the SIN and COS of the angles of the coarse and fine resolvers for each rotor assembly (or referred to as a channel) are applied to a multiplexer. The multiplexer sequentially selects the appropriate channel and the signals are then converted into angular information for each channel. An accurate count of the number of revolutions of the rotatable elements is then obtained. Offset error correction may be provided for each channel. The number of counted revolutions, corrected for offset error, may be multiplied by a scaler for conversion into a linear displacement.