Vehicle Stability Control of Distributed-driven Electric Vehicles Based on Optimal Torque Allocation

Abstract

Abstract: A hierarchical vehicle-stability-control method was presented based on the longitudinal force distribution optimization for the handling and stability control of the distributed-driven electric vehicles. The eight-degree-freedom vehicle models and the three-layer control systems were developed. By selecting the sideslip angle and the yaw rate as the state variables and introducting the virtual control to decouple two control variables， the integral 2-DOF vehicle models were adopted to calculate the equivalent yaw moments for the vehicle stability in upper controllers. The linear quadratic regulator （LQR） method was utilized to optimize the distribution of the front and rear steering angles and the tire longitudinal forces in middle controllers. The sliding-mode-based slip controller in the lower layer was also designed to reallocate the wheel torques. Simulation results show that the control system may make full use of the adhesion potential of the tire under high speed and extreme conditions, realize the coordinated distribution of wheel torques and improve the steering stability of the vehicles. When the actuators fail, the system may reconstruct effectively and realize the reallocation of control inputs to improve the safety of the vehicles.

Key words: distributed-driven electric vehicle, vehicle stability control, control allocation, wheel slip control

摘要：

提出一种基于车轮转矩优化分配的层次化车辆稳定性控制方法，用于分布式驱动电动汽车的操纵稳定性控制。建立八自由度车辆模型，分三层设计控制系统，上层控制器以质心侧偏角和横摆角速度为状态变量，采用积分二自由度控制模型，引入虚拟控制解耦两控制变量，计算车辆稳定的等效横摆力矩；中层采用线性二次型方法，优化分配前后轮转向角和轮胎纵向力；下层控制器设计滑模滑移率控制器，完成定滑移率下的车轮转矩再分配。仿真结果表明，该控制系统在高速极限工况下能充分利用轮胎的附着潜力，实现车轮转矩的协调分配，提高车辆的操纵稳定性；当执行机构出现故障时，系统能有效重构并实现控制量再分配，提高车辆的安全性。

关键词: 分布式驱动电动汽车, 稳定性控制, 控制分配, 滑移率控制

CLC Number:

U461.6

ZHANG Xizheng, ZHENG Liang. Vehicle Stability Control of Distributed-driven Electric Vehicles Based on Optimal Torque Allocation[J]. China Mechanical Engineering.

张细政, 郑亮. [分布式驱动电动汽车动力学控制]基于转矩协调分配的分布式驱动电动汽车稳定性控制[J]. 中国机械工程.

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