基于人-车-路闭环系统的变传动比控制规律

Control law of varied steering ratio based on driver-vehicle-road closed-loop system

提出了一种具有变传动比功能的电动助力转向(EPS)系统,并建立EPS系统变传动比数学模型.采用固定转向增益的控制策略,鉴于特征车速对稳定性的影响,以及转向盘转角对操纵性的要求,提出变动比控制规律的2种方案:方案1是由固定横摆角速度增益和侧向加速度增益得到的变传动比控制规律进行分段线性叠加得到的控制规律;方案2是在方案1的基础上进行转向盘转角修正得到的控制规律.为验证所提出的2种方案,建立了人-车-路闭环系统.基于线性矩阵不等式方法,设计了无刷直流电动机的角位移跟踪鲁棒PID控制器.进行了单移线道路仿真试验,并从转向盘转角和路径跟踪的性能方面,对2种方案进行了对比分析.仿真试验结果表明:变传动比控制规律方案2的整体性能优于方案1.

An electric power steering（EPS） system with varied steering ratio was proposed,and mathematical model of varied steering ratio for EPS system was established.In view of the effects of the characteristic speed on vehicle stability,and the maneuverability requirements of steering wheel angle,two control strategies of varied steering ratio were proposed to obtain constant vehicle steering.The first control strategy was derived by segmented linear superposition of varied steering ratios from yaw rate and lateral acceleration.Based on the first strategy,the second control strategy was deduced by steering wheel angle correction.To verify the proposed two control strategies,driver-vehicle-road closed-loop system was established.Based on linear matrix inequalities,a robust PID controller of angular position tracking was designed for brushless DC motor.Simulation test of single lane change maneuver was carried out to compare the two control strategies according to steering wheel angle and path tracking performance.The simulation results indicate that the second control strategy has better integral performance than that of the first one.