A robust torque control approach for gear shift of a parallel hybrid electric vehicle with dual clutch transmission

This article proposes a robust control strategy for gear shifts of a parallel-type hybrid electric vehicle (HEV) equipped with a dry dual clutch transmission (DCT). A vehicle equipped with DCT requires accurate torque transfer control through the driveline during gear shifts to ensure good shift quality in the absence of smoothing effects from torque converter. Unlike conventional vehicles driven only by internal combustion engines, a HEV can utilize the drive motor to improve its gear shifting performances. In this article, an integrated torque and speed control strategy is developed to minimize the driveline oscillations that occur during gear shifts and to complete the shift as fast as the driver wants. A robust H-infinity controller is designed to control transmission output torque as well as clutch slip speed, particularly in inertia phase that mostly determines the total shift quality. The effectiveness of the proposed control strategy as well as its robustness is verified by comparative studies using a proven vehicle model developed in MATLAB/SimDriveline.