Torque vectoring system design for hybrid electric–all wheel drive vehicle

Abstract

A torque vectoring system is designed for the hybrid electric–all wheel drive vehicle where the front and rear wheels are powered by the combustion engine and electric motors, respectively. The vehicle provides enhanced handling performance by a twin motor drive unit that can distribute the driving and regenerative braking torques to the rear-left and rear-right wheels independently. Based on the driver’s intention, a sliding mode controller is designed to calculate the desired traction force and yaw moment for the vehicle. The force distribution between the front and rear axles is investigated considering the principle of the friction circle, and characteristics of the engine and drive motors. The vertical tire force is estimated using the random walk Kalman filter for the proportional distribution between the front and rear longitudinal forces. For the torque distribution between the rear-left and rear-right wheels, an optimization problem is formulated by considering the constraints of the friction circle and motor characteristics. The proposed algorithm is evaluated in a simulation environment first by reflecting the characteristics of the hybrid electric–all wheel drive modules. Then, the test vehicle is utilized to validate the handling performance experimentally and to compare with the uncontrolled cases.