Robust control for three-position transmission shift actuator assembly

摘要

A robust control (10) for a pressurized-fluid-operated, three-position shift actuator piston assembly (12). The system requires only a single controlled source of pressurized fluid (44) to provide movement to and retention in a selected one of three axially displaced positions (D, N, OD). A solenoid-controlled valve (42) is controlled by pulse width modulation. Current applied to the solenoid coil is controlled (46), voltage (V) applied to the solenoid coil is sensed and used as a control parameter and/or a relatively light detent (48, 50) biases the assembly to a neutral (N) position to provide a robust control.