低附着路面电动助力转向控制策略

车辆在低附着路面转向时转向阻力矩大幅降低,导致转向盘转矩随之减小,严重影响驾驶员的路感,易导致事故的发生.鉴于此,提出电动助力转向电流补偿控制策略以提高低附着路面驾驶员路感.利用扩展卡尔曼滤波方法估计出低附着路面前轴侧向力,进而计算出补偿电流值.在MATLAB/Simulink中建立系统仿真模型,利用实车试验数据与仿真数据对比,验证了仿真模型的准确性.不同行驶工况的仿真结果显示采用本文提出的控制策略后,转向盘力矩显著提高,使驾驶员在低附着路面下的路感与正常高附着路面相同,可以有效防止驾驶员的误操作,提高车辆行驶安全性.

Control Strategy for Electric Power Steering on Low Friction Coefficient Roads

The steering resistance torque decreases dramatically on low friction coefficient roads. It leads to the decrease of the steering torque, which can influence the road feel of drivers to a large extent and cause accidents easily. To address this problem, a current compensation control strategy was proposed to improve the road feel of drivers. Extended Kalman Filter method was used to estimate the lateral force of front axle on low friction coefficient roads. Based on the estimated lateral force, the compensation current was calculated correspondingly. Moreover, the simulation model was built in MATLAB/Simulink, and it was validated by comparing the data of real car experiment with model simulation. Finally, simulation results of different driving conditions show that the steering wheel torque is significantly improved so that the road feel on low friction coefficient roads is equal to that on normal roads by using the proposed control strategy, which can effectively prevent driver's maloperation and improve driving safety.