I. Introduction
The automotive transmission is a necessary and integral part of the automotive propulsion system. In recent years, several innovative transmission systems have been proposed to reduce automotive fuel consumption and emissions, including six and more speeds automatic transmissions, dual clutch transmissions, and electrically variable transmissions (hybrid transmission). To realize the desired functions of these transmissions, a critical component is the transmission clutch, which is used to engage and disengage various rotating shafts and transmit the engine power to the vehicle. Detailed descriptions of the transmissions and the functionality of the clutch can be found in [1].