Abstract: An apparatus and method for controlling a plurality of clutches in a powershift transmission. The transmission is coupled to an engine of an off-road vehicle. The method includes receiving a shift command having a shift direction. Clutch timing is selected based on the shift direction. Using the selected shift timing, on-coming clutches are engaged in sequence with disengagement of off-going clutches to achieve smooth shifting.

Abstract: An apparatus and method for controlling a plurality of clutches in a powershift transmission. The transmission is coupled to an engine of an off-road vehicle. The method includes receiving a shift command having a shift direction. Clutch timing is selected based on the shift direction. Using the selected shift timing, on-coming clutches are engaged in sequence with disengagement of off-going clutches to achieve smooth shifting.

Abstract: An electronic control system for a transmission in a work vehicle such as an agricultural tractor is provided herein. The system includes sensors for detecting the output speed of the vehicle engine, the output speed of the transmission and the vehicle ground speed. Command devices are available to the vehicle operator for generating command signals, such as for commanding the direction of movement, as well as forward and reverse gear ratios. A controller receives signals from the sensors and command devices, and controls engagement and disengagement of combinations of fluid clutches in the transmission to obtain desired gear ratios between the transmission input and output shafts. The system stores default forward and reverse gear ratios which are used upon start-up of the vehicle. To permit limited modification of the default gear ratios, an interface separate from the vehicle is provided to modify the default gear ratios.

Abstract: An electronic control system for a transmission in a work vehicle such as an agricultural tractor is disclosed herein. The system includes sensors for detecting the output speed of the vehicle engine, the output speed of the transmission and the vehicle ground speed. Command devices are available to the vehicle operator for generating command signals, such as for commanding the direction of movement, as well as forward and reverse gear ratios. A controller receives signals from the sensors and command devices, and controls engagement and disengagement of combinations of fluid clutches in the transmission to obtain desired gear ratios between the transmission input and output shafts. The command devices include an input device for generating transmission command signals, and the controller responds by selectively engaging the clutches to shift the transmission at a predetermined shift rate. The controller determines a commanded gear ratio based at least in part on the transmission command signals.

Abstract: A method and system for calibrating at least one clutch in a transmission whereby the incipient engagement pressure of the fluid in the clutch may be determined. Two shafts in the transmission are locked together in mutually incompatible gear ratios thereby preventing their free relative rotation. The output of the clutch is connected to these shafts to prevent its free rotation. The input of the clutch is connected to the engine to cause it to rotate. The clutch is then gradually engaged as the load on the engine is monitored, preferably by measuring changes in the fuel flow rate to the engine. Once the engine load increases a predetermined amount, the system saves the particular valve command signal that produced the incipient engagement pressure and the process ends. The method is preferably performed entirely under microprocessor control, thereby eliminating the need for operator intervention during the process.

Abstract: A control system for controlling outputs associated with off-road vehicles is disclosed herein. The outputs are actuated by actuators in response to control signals generated by a control circuit. In a normal mode, the control circuit generates the control signals based upon command signals generated by operator-actuatable command devices, and applies the control signals to the actuators to control the outputs. In a record mode, the control circuit stores a sequence of commands in a memory circuit to record the sequential actuations of the command devices. Then, in a playback mode, the control circuit generates the control signals based upon the recorded command sequence instead of the command signals. Playback can be triggered manually by a playback switch, or automatically based upon the geo-graphic position of the off-road vehicle. The control system can record and playback more than one command sequence.

Abstract: Disclosed herein is a control system for controlling the position of the harvesting implement of an agricultural vehicle. The system includes transducers for monitoring the position of the implement relative to the vehicle, the location of the implement relative to the surface supporting the vehicle, and the force required to support the implement. The system also includes an implement positioning mechanism, a user interface for selecting position, location and force setpoints, and a controller coupled to the transducers, positioning mechanism and user-interface. Based upon the signals produced by the transducers and the setpoints set at the user-interface, the controller controls the positioning mechanism to position the implement.

Abstract: An electronic control system for controlling the position of a combine harvesting head operable over a surface is disclosed herein. The position is controlled based upon the force or pressure at which the surface is supporting the implement. In particular, a hydraulic positioning assembly positions the head relative to the combine based upon control signals produced by a digital control circuit. The digital control circuit monitors digital signals representative of the force at which the surface is supporting the head, and compares these signals with digital setpoint data associated with a desired support force. Based upon the comparison, the control circuit produces control signals for causing the positioning assembly to raise or lower the harvesting head relative to the surface.

Abstract: An electronic control system for controlling the position of a combine harvesting head operable over a surface is disclosed herein. The position is normally controlled based upon the monitored position of the head. However, the position is controlled based upon the force or pressure at which the surface is supporting the implement if this force exceeds a predetermined limit. Thus, the system provides for float control override of position control. In particular, a hydraulic positioning assembly positions the head relative to the combine based upon control signals produced by a digital control circuit. The digital control circuit monitors digital signals representative of the head position and the force at which the surface is supporting the head, and compares these signals with digital setpoint data.

Abstract: A control system for controlling the height of a harvesting head on a combine is disclosed herein. The control system includes operator controlled signal generators which permit an operator to independently set the maximum velocity at which the harvesting head is raised and lowered. The signal generators are connected to the system controller which controls the operation of a hydraulic valve which controls hydraulic lift cylinders which raise and lower the harvesting head. The hydraulic valve is controlled with a pulse-width modulated signal. The width of the pulse is related to the direction the head is being moved (raised or lowered), and the maximum speed at which the head is to be moved. To reduce jerking upon initiation of head movement and termination of head movement, the controller determines acceleration and deceleration rates for head movement initiation and termination. The acceleration and deceleration determinations are based upon the signals produced by the signal generators.

Abstract: An improved electronic control system for a vehicle transmission system having a plurality of sequential gear ratios allows the vehicle operator to selectively engage either a normal sequential gear ratio progression or a gear ratio progression that skips or omits certain low gear ratios from the gear ratio shift sequence. The transmission control system includes a microprocessor driven electronic control circuit that governs the transmission operation by selectively actuating, from a plurality of hydraulic clutch solenoid valves, a unique combination of solenoid valves for each gear ratio. Manually operable control means allows the vehicle operator to cause the microprocessor to select a software routine that omits certain solenoid valve combinations so as to progress through the transmission gear ratios during upshifts in the forward control mode at a faster rate, thus improving the acceleration of the vehicle in the low gear ratio range.

Abstract: The improved steering controller is of the type used to control the angular position of the rear wheels on a four-wheel-steer vehicle as a function of the angular position of the front, operator-steered wheels. The controller includes a computing section, a visual display of the alpha-numeric type and a visual indicator which provides a bar-like display having a number of individual "markers" arranged in a row. The apparent length of such bar-like display, which changes as markers are illuminated, apprises the vehicle operator of the approximate magnitude and direction of angular displacement of the rear wheels from the centered position. The alpha-numeric visual display indicates operational mode as well as "errors" used in troubleshooting diagnosis and repair.