四轮转向车辆转向解耦的双点跟踪控制

针对四轮转向(4WS)无人车辆路径跟踪中的过约束问题, 本文提出一种前后轮转向解耦的双点跟踪控制策略. 建立4WS车辆单轨运动学模型, 约束前后轮转向角速度, 规划曲率连续的回旋曲线参考位姿序列, 将其解耦为前后轴中心的双点参考轨迹; 以前后轮中心点为控制点, 采用非线性反馈控制的预瞄方法分别获得转向控制率, 双点跟踪误差指数收敛于0. 仿真和实车验证结果表明, 所提出的双点跟踪控制策略横向误差标准差减少0.2 m, 横摆角误差标准差减小3.0?, 具有更大的前后轮转角控制域和较高的跟踪精度

Dual-point tracking control for four-wheel steering vehicle steering decoupled

Aiming at the problem of front and rear wheels steering over-constraint in the path tracking of four-wheel steering (4WS) unmanned vehicles, a decoupled dual-point tracking control method is proposed. The 4WS vehicle single-track kinematics model is established. Based on the cyclotron curve path planning method, with the constraint of the front and the rear wheel angular velocity, a reference pose sequence with continuous curvature is planned and decoupled into two reference trajectories of the center point of the front and rear axles. With the center point of front and rear wheel as the control point, the non-linear feedback control method is adopted to obtain the steering control rates separately. The two-point tracking error is exponentially converged to 0. The results of simulation and real vehicle verification show that the standard deviation of the lateral error is reduced by 0.2 m and the yaw angle error is reduced by 3.0?. The algorithm has a larger front and rear wheel angle control domain and higher tracking accuracy