Nonlinear Torque Observer for a Self-Energizing Clutch Actuator Using a Reaction Torque Estimation Approach

Clutch torque estimation is an important problem in automotive transmission control. Particularly, a self-energizing clutch actuator system has a novel mechanism to amplify the clutch torque for reducing actuation energy. Instead of low energy consumption, the clutch torque is highly sensitive to the actuator stroke, which makes the torque detection difficult. The nonlinear disturbance observer is designed such that the clutch torque is estimated with guaranteeing asymptotic convergence by using the actuation motor position signal. This type of observer is based on the reaction torque estimation approach with respect to the actuator dynamics without considering vehicle driveline information. The experimental results show that the developed method is useful to identify the load characteristics of a self-energizing clutch actuator system.