Cooperative Control of Drive Motor and Clutch for Gear Shift of Hybrid Electric Vehicles With Dual-Clutch Transmission

This article deals with the cooperative control of drive motor and clutches for the gear shift of a parallel hybrid electric vehicle (HEV) with a dual-clutch transmission (DCT). An HEV with DCT powertrain requires the sophisticated control of two clutch actuators and power sources to achieve outstanding gear shift performances. In this article, a new shift control strategy based on the feedback of both speed and torque states is implemented to improve the shift quality. Different from previous approaches, the proposed control uses the dynamic torque observer to accurately track the desired transient torque during the inertia phase. Since a drive motor is installed in the HEV's driveline, the transient torque through the driveline can be effectively controlled by using the fast dynamic characteristics of the drive motor. A major difficulty arising from the shift control of DCT is the interactions between the speed and torque control loops. To treat the coupling effects effectively even in the presence of model uncertainties and disturbances, a robust multivariable control scheme using H-infinity loop shaping is suggested, especially for the inertia phase control. The performance of the final-observer-based controller is demonstrated through real-time experiments. A comparative study with the conventional control approach is also conducted, and detailed discussions of the results are provided.