线控双电机转向系统滑模同步控制及其硬件在环仿真

为了满足高等级自动驾驶转向执行机构的高安全性需求，研究一种采用冗余双电机转向执行机构的线控转向系统，针对双电机在转角伺服控制过程中存在的不同步问题，提出一种基于滑模控制的同步控制策略。首先，对采用冗余双电机转向执行机构的线控转向系统进行结构原理的分析，建立线控系统转向执行机构模型和车辆二自由度模型；然后，为实现转向执行机构的转角伺服控制，在位置、速度、电流的三闭环控制策略的基础上设计速度同步控制器。为解决2个转向执行电机运行过程中存在的速度不同步问题，采用滑模控制方法，将2个电机的转速差值作为控制器的输入量，得到双电机电流的补偿量，并将其叠加至双电机的目标电流中。同时，将上述控制策略与传统PID控制进行对比仿真试验，验证了基于滑模同步控制的线控双电机执行器能够更好地协调双电机的转速，实现双电机同步运行。最后，搭建线控转向硬件在环试验台，对所设计的控制策略的有效性进行验证。结果表明：所设计的双电机线控转向系统滑模同步控制策略能够在实现转角伺服控制的同时，减少双电机的速度不同步现象，保证线控转向系统转角伺服的同步性能。

Sliding Mode Synchronous Control and Hardware-in-loop Simulation of Dual-motor Steering-by-wire System

To meet the high safety standards of high-grade automatic-driving steering actuators, a steering-by-wire system with redundant dual-motor steering actuators was studied. To address the problem of unsynchronized dual-motor steering servo control, a synchronous control strategy based on sliding mode control was proposed. First, the structural principles of a steering-by-wire system with redundant dual-motor steering actuators were analyzed, and a steering actuator model of a steering-by-wire system and a two-degree-of-freedom vehicle model were established. Then, to realize the angle servo control of the steering actuators, a speed synchronization controller was designed based on closed-loop control strategies for position, speed, and current. To handle speed unsynchronization in the operation of the two steering motors, a sliding mode control method was adopted. The speed difference between the motors was used as the input of the controller, and the compensation amount for the current of the dual motor was obtained, which was superimposed on the target current. Moreover, by comparing the proposed control strategy with traditional PID control, it was verified that the wire-controlled dual-motor actuator based on sliding mode synchronous control can better coordinate the speed of the dual motor and realize synchronous operation. Finally, a hardware-in-loop test bench for a steering-by-wire system was constructed to verify the effectiveness of the proposed control strategy. The results demonstrate that the sliding mode synchronous control strategy of the dual-motor steering-by-wire system can realize angle servo control, reduce the speed synchronism of the dual-motor, and ensure synchronous operation of the angle servo of the steering-by-wire system.