四轮独立转向-独立驱动电动车主动避障路径规划与跟踪控制

Path Planning and Tracking Control for Collision Avoidance of a 4WIS-4WID Electric Vehicle

四轮独立转向-独立驱动电动车(4WIS-4WID EV)具有低速机动性强、高速稳定性好的特点,是一种理想的智能车构型。本文中针对4WIS-4WID EV进行了主动避障系统的设计,主要包括避障路径规划和跟踪控制。首先基于车辆运动学模型,提出了采用七次多项式的避障路径规划算法;然后基于简化2自由度车辆动力学模型,设计了模型预测路径跟踪控制器;为提高车辆主动避障过程中的操纵稳定性,路径跟踪控制算法采用四轮转向与直接横摆力矩控制技术。通过不同附着系数路面工况与侧风扰动工况仿真,验证了所设计的主动避障系统具有良好的避障能力和鲁棒性。

Four-wheel independent steering and four-wheel independent drive electric vehicle (4WIS-4WID EV) has good maneuverability at low speed and superior stability at high speed, so is an ideal autonomous vehicle. An active collision avoidance system for 4WIS-4WID EV is designed in this paper, mainly consisting of path planning and tracking control. Firstly, the path planning algorithm for collision avoidance is proposed using seven-order polynomial based on vehicle kinematic model. Then, the model predictive controller for path tracking is designed based on the simplified 2 DOF dynamic model. Four-wheel steering and direct yaw-moment control are applied to the path tracking algorithm to improve the handling stability of vehicle. The active collision avoidance performance and robustness of the system are verified by simulations under the conditions of different road adhesive coefficients and crosswind disturbance.