When a four-wheel-drive hybrid electric vehicle (HEV) with dual clutch transmission (DCT) is decelerating while turning, the vehicle often transits from front-wheel hybrid mode to electric mode of the rear hub motors, in order to improve the energy efficiency. However, the mode transition process is accompanied by the driving torque front-to-rear axis conversion and the wheel load transfer. And the mode transition process involves not only the torque coordinated control of the multi-power sources, but also the differential control of the left and right rear hub motors. If not properly controlled, it will cause a large jerk and the vehicle to be unstable. In this paper, a seven degrees of freedom (DOF) of vehicle model integrated with DCT powertrain system is introduced to reflect its lateral and longitudinal dynamic characteristics in the mode transition process. The optimal control strategy considering the differential distribution of the rear hub motors’ torque is proposed based on sliding-mode control (SMC). Simulation and hardware-in-the-loop (HIL) test results show that the proposed mode transition control strategy can not only achieve smooth front- to rear-end driving torque switching and reduce the jerk 5.7%, but also improve the tracking performance of side slip angle and the yaw rate.

采用双离合变速器（DCT）的四轮驱动混合动力电动汽车（HEV）在转弯时减速时，车辆往往会从前轮混合动力模式过渡到后轮毂电机的电动模式，以提高能量效率。然而，模式转换过程伴随着驱动扭矩前后轴转换和轮载转移。并且模式转换过程不仅涉及多动力源的扭矩协调控制，还涉及左右后轮毂电机的差动控制。如果控制不当，会导致较大的颠簸和车辆不稳定。在本文中，引入了与DCT动力总成系统集成的车辆模型的七自由度（DOF），以反映其在模式转换过程中的横向和纵向动态特性。提出了基于滑模控制(SMC)的考虑后轮毂电机转矩差异分布的最优控制策略。仿真和硬件在环（HIL）测试结果表明，所提出的模式转换控制策略不仅可以实现平滑的前后端驱动扭矩切换，降低 5.7% 的 jerk，而且提高了跟踪性能。侧滑角和偏航率。