Image Number 4 for United States Patent #4936405.
A feedback control system and method for controlling the wheel slip of a wheel driven by torque coupled through an electronically controlled hydraulically operable clutch from an internal combustion engine. A first feedback variable related to wheel slip and a second feedback variable related to hydraulic pressure applied to the clutch are summed to generate a feedback control signal. In response to the feedback control signal, the clutch is slipped by regulating the hydraulic pressure to reduce the driven wheel speed. Engine speed is adjusted in response to a measurement of driven wheel speed to prevent over-revving of the engine and maintain a desired predetermined positive torque on the driven wheel while the clutch is being slipped.