In order to achieve the dynamic switching of steering modes for four-wheel independent steering (4WIS) electric vehicles, and to make full use of the redundant control degrees of freedom, the switching process and control method were studied by using the modeling and simulations. For switching method, a wheel trajectory planning method based on B-spline curve is proposed, and then the trajectories of four independent wheels were calculated. The simulation results show that the dynamic switching of steering modes was accomplished, and the kinetic parameters meet the requirements for switching. For mode switching control method, the virtual connection between four independent wheels were established, based on which a control strategy named dynamics and kinematics compound control is proposed. The simulation results verify the stability and robustness of the proposed control strategy.%为了实现四轮独立转向(Four Wheel Independent Steering,4WIS)电动汽车的转向模式不停车动态切换,充分利用4WIS电动汽车的冗余控制自由度,对转向模式切换过程与控制方法进行建模与仿真研究.在切换方法上提出了一种基于B样条曲线的车轮轨迹规划方法,在此基础上实时计算4个独立车轮的运动轨迹.仿真结果表明,该方法能够实现4WIS电动汽车转向模式的不停车平滑切换,切换过程中动力学参数满足要求.在模式切换控制方法上,针对4WIS电动汽车车轮独立的特点,构建4个车轮之间的虚拟连接关系,提出一种"运动学-动力学"复合控制策略,提高了动态切换控制的稳定性与鲁棒性.仿真结果验证了该算法的有效性.
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