Design of hybrid position/force engagement controller for dry dual clutch transmission without diaphragm spring

This paper suggests a position/force hybrid controller for the dry dual clutch transmission actuators that provides accurate desired clutch normal force tracking performance and also dramatically reduces clutch-transferred torque fluctuation and wheel jerk during vehicle launch and gear shifts when compared to conventional position-based controllers. The proposed controller is composed of a multiple surface sliding mode controller with current estimation for the position-based control and feed-forward clutch normal force controller with clutch normal force estimation for force-based feedback control. Strategy to merge these controllers is suggested for effective actuator control both during the disengaged and engaged phases, which especially serves a significant advantage in clutch control for the system with minimal clutch engagement stroke designed for high actuation efficiency. In order to verify such advantage, the suggested controller is tested on the driveline model for dual clutch transmission and clutch actuators for the clutch system without diaphragm spring that are designed using MATLAB/Simulink. The simulation results reveal that accurate clutch normal force control with reduced jerk is possible even in the absence of the diaphragm spring.