Adaptive slip engagement control of a dry clutch using a clutch torque estimator

A dry clutch is an important part in a vehicle powertrain system and the dry clutch is primarily utilized for small and medium sized vehicles. The slip engagement is a method of engaging a clutch in a state where the speeds of both sides of the clutch are different. When a clutch is slipping, energy loss due to clutch friction, and clutch wear occurs. Therefore, it is necessary to control a clutch precisely in slip engagement of a clutch. A clutch friction model is needed to implement feedforward control in clutch slip engagement control, but there are some uncertain parameters in a clutch friction model. In this study, a clutch friction coefficient and a clutch touch point are represented as uncertain parameters of a clutch friction model. Thus, a simultaneous adaptation method of a clutch friction coefficient and a clutch touch point in a clutch friction model, and a feedforward control method of slip engagement of a dry clutch using the adaptation method are proposed in this study. The proposed adaptive control algorithm was verified with the slip engagement simulation of a dry engine clutch in a parallel hybrid vehicle in the MATLAB/Simulink environment.