电动助力转向(EPS)系统是电动汽车设计装配过程中的关键部件之一,EPS的阻尼控制可提高汽车高速行驶时横摆角速度的收敛,改善转向稳定性.建立EPS系统动力学模型和汽车三自由度转向模型,分析电动机转速与输出转矩之间的制动转矩关系,设计阻尼系数随车速的变化规律.设计Bang - Bang - PID控制算法,进行了仿真分析.以某微型轿车为试验对象,设计了汽车EPS系统实车试验平台,在80 km/h直线行驶状态下进行阻尼控制试验.结果表明:与无控制相比,原车控制的最大把持力矩降低49.45％,Bang - Bang -PID控制的最大把持力矩降低57.14％；与原车控制相比,Bang - Bang - PID控制的最大把持力矩降低7.69％.系统具有更短的收敛速度和更强的抗干扰能力,提高了汽车的行驶稳定性.%Electric power steering (EPS) system is one of the key parts of electric vehicle in design and assembly. The damping control of EPS system can increase the convergence of yaw rate and improve the steering stability at high speed. The EPS system dynamics model and three degrees of freedom model were established. The damping coefficient with the speed variation was designed by analyzing the braking torque relationship between the motor speed and output torque. The Bang-Bang-PID control algorithm was designed and the simulation analysis was carried out. The real test setup was designed based on a mini-car and the damping control test was made under straight line condition in 80km/h. The results showed that the maximum torque reduced 49. 45% under the original vehicle controller compared with no controller, while the Bang-Bang-PID controller was 57. 14% ; the maximum torque reduced 7. 69% under Bang-Bang-PID controller compared with the original vehicle controller. The system has shorter convergence speed and stronger anti-interference ability so as to improve the vehicle driving stability.
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