Abstract: A flow control valve includes a housing that includes a fluid inlet, a fluid outlet, a first work port and a second work port. The housing defines a spool bore and a pilot spool bore. A main stage spool is disposed in the spool bore. A pilot stage spool is disposed in the pilot spool bore. The pilot stage spool is in selective fluid communication with the main stage spool. A microprocessor includes a controller having a restricted structured controller and a compensation controller. Outputs of the restricted structured controller and the compensation controller are summed to form an electrical signal that is communicated to the pilot stage spool.

Abstract: Methods for controlling the net-displacement of a rotary fluid pressure device are disclosed. One of the net-displacement control methods (47) includes obtaining a desired input parameter (23) and a relative position (21) of a first member (43) and a second member (35) of a fluid displacement mechanism. A determination of a first and second output value is then made for each of a plurality of volume chambers (45) when the volume chambers (45) are supplied with fluid at fluid inlet and fluid outlet conditions, respectively. A total output value is then computed for each of a plurality of control valve configurations (63) and compared to the desired input parameter (23). The control valve configuration (63) with the total output value most similar to the desired input parameter (23) is then selected. A plurality of control valves (15) are then actuated in accordance with the selected control valve configuration (63).

Abstract: A method for estimating actuator position includes the steps of receiving fluid pressure data signals from a plurality of fluid pressure sensors (31), receiving spool position signals from at least one spool position sensor (33), and receiving actuator position data signals from at least one actuator position sensor (35). Corrected flow rates to and from an actuator (21) are determined with each corrected flow rate being based on fluid pressure data signals, the spool position signals, and an error-correction factor, wherein the error-correction factor is a function of the fluid pressure data signals and the spool position signals. An estimated actuator position is determined wherein the estimated position includes a kinematic component and a dynamic component. Adaptive gain factors are applied to calibrate the estimated actuator position to the actuator position data signals from the actuator position sensor.

Abstract: An method for estimating actuator position includes the steps of receiving fluid pressure data signals from a plurality of fluid pressure sensors (31), receiving spool position signals from at least one spool position sensor (33), and receiving actuator position data signals from at least one actuator position sensor (35). Corrected flow rates to and from an actuator (21) are determined with each corrected flow rate being based on fluid pressure data signals, the spool position signals, and an error-correction factor, wherein the error-correction factor is a function of the fluid pressure data signals and the spool position signals. An estimated actuator position is determined wherein the estimated position includes a kinematic component and a dynamic component. Adaptive gain factors are applied to calibrate the estimated actuator position to the actuator position data signals from the actuator position sensor.

Abstract: A control system for a vehicle having first and second axles is provided that includes a coupling apparatus adapted to distribute torque between the first and second axles and a traction controller for controlling operation of the differential apparatus from vehicle launch up to a predetermined vehicle speed. The traction controller is configured to engage the coupling apparatus in a first operating state according to at least one vehicle operating parameter indicative of a low traction operating condition and to further control engagement of the coupling apparatus in a second vehicle operating state during the low traction operating condition according to a difference between an actual vehicle yaw rate and a predetermined target vehicle yaw rate.

Abstract: A method for controlling stability of a vehicle includes the steps of determining a predictive lateral load transfer ratio of the vehicle by evaluating vehicle performance factors over a period of time, and controlling operation of the vehicle based on the predictive lateral load transfer ratio.

Abstract: A control system for a vehicle having first and second axles is provided that includes a coupling apparatus adapted to distribute torque between the first and second axles and a traction controller for controlling operation of the differential apparatus from vehicle launch up to a predetermined vehicle speed. The traction controller is configured to engage the coupling apparatus in a first operating state according to at least one vehicle operating parameter indicative of a low traction operating condition and to further control engagement of the coupling apparatus in a second vehicle operating state during the low traction operating condition according to a difference between an actual vehicle yaw rate and a predetermined target vehicle yaw rate.