Oscillation suppression is essential for the stability design of electric power steering (EPS) systems. The stability controller module in EPS controller is the key to solve the stability control problem of EPS system. This paper proposes a new method of stability analysis and stability controller module design for EPS systems. Furthermore, the dynamic characteristics of the EPS system are analyzed, and two critical factors on the resulting EPS stability, that is, large assist and variable assist gain are investigated experimentally. The transfer function from steering torque to sensor torque is redefined. A new transfer function is proposed for measuring the effect of variable assist gain on system performance. Based on the above factors and transfer functions, constraints on the stability controller design are proposed. Then the optimal parameters in the controller are obtained by maximizing an objective function including phase margin, gain margin, and crossover frequency. It is concluded from simulations and bench tests that the proposed stability controller can significantly reduce the torque oscillation of the EPS system.

振荡抑制对于电动助力转向 (EPS) 系统的稳定性设计至关重要。EPS控制器中的稳定性控制器模块是解决EPS系统稳定性控制问题的关键。本文提出了一种新的EPS系统稳定性分析和稳定性控制器模块设计方法。此外，分析了EPS系统的动态特性，并通过实验研究了影响EPS稳定性的两个关键因素，即大辅助和可变辅助增益。重新定义了从转向扭矩到传感器扭矩的传递函数。提出了一种新的传递函数，用于测量可变辅助增益对系统性能的影响。基于上述因素和传递函数，提出了稳定性控制器设计的约束条件。然后通过最大化包括相位裕度、增益裕度和交叉频率的目标函数来获得控制器中的最佳参数。仿真和台架试验得出的结论是，所提出的稳定性控制器可以显着降低 EPS 系统的扭矩振荡。