Torque Distribution Algorithm for Four In-wheel Motors Drive Electric Vehicle Based on Torque Vector Control

Abstract

Torque distribution algorithm, including the calculation of additional yaw moment and the distribution of four in-wheel motors torque, is studied. An additional yaw moment controller based on the MPC is designed. The predictive model is constructed based on 2-DOF vehicle model. The optimal additional yaw moment is obtained by solving the equivalent quadratic programming problem, which considers the constraints of target yaw rate, CG sideslip angle and minimum variation of additional yaw moment.Wheel torque distribution based on the optimal tire adhesion coefficient is established to realize additional yaw moment. Combined with the constraints of front and rear axle driving force, additional yaw moment and tire friction circle, the optimal wheel force distribution problem is transformed into a quadratic programming problem. In the special conditions such as lateral force saturation and driving anti-skid function trigger, the constraints are relaxed to avoid the equation without feasible solution.The simulation results of transient steering test, steady state steering test and extreme steering test showed that the application of the algorithm can shorten the response time of yaw rate, improve the cornering behavior of the vehicle under large lateral acceleration, and reduce the maximum passing speed under in slalom test to improve the handling and stability of the vehicle.