基于路面附着系数估计的EPS助力控制研究

Research on EPS Assisted Control Based on Road Adhesion Coefficient Estimation

在建立EPS系统动力学模型的基础上,通过模糊算法得出路面附着估算修正因子用来修正路面附着估算模型,并通过限幅滤波得出路面附着系数估计值。将路面附着系数和车速作为输入,设计了模糊控制器输出助力电流修正系数。根据助力电流修正系数和此时的方向盘转角信息得出修正电流,并在此基础上设计了准滑模助力控制策略。仿真结果表明,该控制策略可有效改善车辆在不同附着路面下的操纵路感。搭建了硬件在环试验平台,对助力控制策略进行试验验证,试验结果与仿真结果基本一致。

In this paper,based on the EPS system dynamics model,correction factor of estimation was obtained by fuzzy algorithm to correct estimate model of road adhesion.The road adhesion coefficient and speed were used as inputting of the fuzzy controller which was designed to output the correction coefficient of assisted power current.The correction current was obtained through the correction coefficient of assisted power current and the steering angle information of the steering wheel,and,on the basis of that,the quasi-sliding mode power assisted control strategy was designed.The simulation results showed that the control strategy can effectively improve the road feel of the vehicle on the different adhesion coefficient road.The hardware-in-the-loop test platform for EPS is established,and the assistant torque control strategy based on road friction is validated on the platform.The test result is consistent with the simulation result.