分布式驱动车辆的主动后轮转向与直接横摆力矩协调控制OA

To solve the instability issue of distributed drive vehicles running on high-speed and low-adhesion road surfaces,the joint coordinated control strategy for active rear steering and direct yaw moment control was developed.In the proposed scheme,the hierarchical control architecture was adopted.The phase plane method was used to define the vehicle stability region,and the yaw rate threshold method was applied to supplement the stability judgment criteria.By the upper-layer coordination controller,the control weights for the two subsystems were dynamically distributed according to the stability region,while in the lower-layer controller,the linear quadratic regulator was utilized to realize the rear wheel steering angle control.When the vehicle was detected to be on the verge of instability,the super-twisting sliding mode control was adopted to calculate the required additional yaw moment.With the tire load ratio as constraint,the quadratic programming algorithm was employed to achieve optimal four-wheel torque distribution and implement direct yaw moment control.The simulations were conducted under two typical operating conditions of medium-high speed on icy road surfaces and high speed on wet cement road surfaces.The experimental results verify that the proposed coordinated control strategy can remarkably improve the vehicle maneuverability and driving stability and effectively reduce the risk of vehicle instability.