Abstract: A default mode control system for controlling a split torque transmission is disclosed. The default mode control system monitors various inputs to the control to detect an on board electrical, electronic fault or mechanical, hydraulic fault. When a fault is detected, the default mode control will recover from the default and then will limit operation of the split torque transmission based on the fault input.

Abstract: The present invention relates to a method and system for controlling a split torque transmission having a hydrostatic transmission and a mechanical transmission. The control system employs a transmission control and includes a transmission input speed sensor, a transmission output speed sensor, a motor speed sensor, a speed input mechanism, a direction control mechanism, and a range selector mechanism. A microprocessor including a fuzzy controller controls the transmission in response to a input from the speed sensors and the speed input mechanism, the direction control mechanism and the range control mechanism.

Abstract: A downstream rate limiting control is provided for controlling a continuously variable transmission. The rate limiting control monitors a input and a current machine state and computes the difference between these two inputs and compares the computed error to a predefined rate table to determine if the computed error should be limited or modified. The rate signal will modify the computed error within the control logic with respect to operator comfort and machine parameters.

Abstract: A method is disclosed for providing a smooth power transition between a variable displacement pump and a variable displacement motor when a mechanical feedback is not provided. The method includes sensing and comparing the speeds of the variable displacement pump and the variable displacement motor based on known maximum volumetric displacements and reducing the rate of change of displacement of one of the variable displacement pump or the variable displacement motor when it is determined that the one is near its maximum displacement position and simultaneously initiating a change in displacement of the other thereof. The subject arrangement ensures that there is no detrimental interruptions of power during the transition of changing of displacement of one of the variable displacement pump and the variable displacement motor to changing the displacement of the other one thereof.

Abstract: An integrated power transmitting system includes a hydrostatic transmission and a mechanical transmission both being driven by an engine. The output of the hydrostatic transmission and the mechanical transmission are both selectively coupled to a work system through a final output shaft. A sensing arrangement senses the transmission input speed, the output of the hydrostatic transmission and the speed of the final output shaft and delivers the signals to the microprocessor. The microprocessor processes the received signals on a continuous basis and delivers a first set of command signals to control operation of the hydrostatic transmission and a second set of control signals to selectively control forward and reverse direction and high and low clutches within the mechanical transmission. A planetary arrangement within the mechanical transmission sums the speed of the hydrostatic transmission with a full range forward and reverse gear mechanism.

Abstract: A method is disclosed for providing different speed ranges for a speed pedal in a continuously variable transmission having a closed loop control. The method comprises the steps of monitoring the output speed of the continuously variable transmission, monitoring the position of the speed pedal relative to the transmission output speed, establishing a plurality of control maps each having the same travel distance of a speed pedal but different speed ranges, and selecting the desired speed range relating to one of the plurality of control maps. This enables the operator to select a speed range to fit the operation, such as, travelling from one location to another, maneuvering, or loading a truck.