基于抗饱和特性的EPS助力控制研究

Research on EPS Assisted Control Based on Anti-saturation Characteristics

电动助力转向系统中大多数采用PID控制,存在积分饱和现象,在方向盘频繁转动等情况会使积分饱和现象更加严重,影响汽车的操纵稳定性和轻便性,因此需要采用抗饱和特性的PID控制器来提升系统的稳定性和轻便性。在MATLAB中建立EPS的系统动力学模型、模糊助力控制曲线和anti-windup变结构自适应PID控制器模型,将建立的模型与carsim进行联合仿真,对比传统PID控制对于汽车操纵稳定性的影响;借助NXP的MBD工具箱进行自动代码生成,生成的基于anti-windup的变结构自适应控制器和传统PID控制器的程序进行实际台架实验。经carsim仿真和台架实验证明:基于anti-windup的变结构自适应的PID控制器有效降低了汽车侧向加速度和方向盘的转矩。系统具有了更小的侧向加速度,提高了系统操作稳定性;方向盘的转矩降低,提高了驾驶员的路感和系统转向轻便性。

Most of the electric power steering systems use PID control and have an integral saturation phenomenon. The frequent rotation of the steering wheel and other conditions will make the phenomenon of saturation more serious, affecting the ca^s handling stability and portability. Therefore, the PID controller with anti-saturation characteristic is needed to improve the stability and portabil-ity of the system. The EPS system dynamics model, fuzzy boost control curve and anti-windup variable structure adaptive PID control-ler model are established in MATLAB. The combined simulation of the model and GarSim is carried out to compare the influence of the traditional PID control on the vehicle handling and stability. Using NXP？s S32kl44 toolbox to generate embedded G code Simulink model, the actual bench test is carried out by the anti-windup based variable structure adaptive controller and the traditional PID con-troller. GarSim simulation and bench test show that anti-windup based variable structure adaptive PID controller effectively reduces ve-hicle lateral acceleration and steering wheel torque. The system has a smaller lateral acceleration, which improves the operating stabil-ity of the system. The torque of the steering wheel is reduced, which enhanced the driver’s sense of road and the portability of the steering system.