基于状态反馈的分布式驱动电动汽车操纵性改善控制方法

研究分布式驱动电动汽车直接横摆力矩控制问题。提出基于状态反馈的操纵性改善控制策略：利用横摆角速度反馈改善车辆的横摆角速度瞬态响应，利用转向角前馈提高车辆的稳态横摆角速度增益。根据反馈系数对车辆瞬态响应特性的影响建立优化函数，获取不同车速下最优反馈系数。基于转向助力需求设计前轴差动转矩约束，再结合后轴的电动机外特性约束，获取不同车速下最大前馈系数。设计四轮转矩分配策略，在实现直接横摆力矩控制的同时满足驾驶员的加速需求。多工况下仿真验证表明，算法在改善横摆角速度的瞬态响应和稳态增益的同时可以减少转向盘力矩，降低驾驶员操作负荷；直接横摆力矩的引入有效地抑制了加速过程中的不足转向，平衡了前后轴的侧向附着利用率，提高了车辆的侧向稳定裕度。

Handling Improvement for Distributed Drive Electric Vehicle Based on State Variable Feedback Control

The direct yaw moment control for distributed drive electric vehicle is studied. A handling improvement algorithm based on state variable feedback control is proposed. The yaw rate feedback is employed to improve the transient response of the yaw rate, the steer angle feedforward is employed to increase the steady gain of the yaw rate. According to the feedback coefficient’s influence on the transient response, an optimization function is proposed to obtain optimum feedback coefficients under different speeds. The constraint of differential torque on the front axle is calculated from the requirement of power steering, together with the motor exterior characteristic constraint of the rear axle, the maximum feedforward coefficients under different speeds are obtained. A torque distribution algorithm is presented to help the driver to speed up during the direct yaw moment control. Simulations under multiple maneuvers is carried out. While the transient response and the steady gain of the yaw rate are improved, the algorithm can also decrease the steering wheel torque; the direct yaw moment control can rectify the understeering caused by accelerating, balance the friction usage of two axles, and increase the lateral stability margin of the vehicle.