踏板耦合式电动助力器踏板脚感抖动抑制研究

Jitter suppression of a pedal-coupled electric booster for improving its pedal foot feeling

电子液压制动(EHB)系统用踏板耦合式电动助力器的助力电机在堵转控制下,其扭矩脉动容易引起制动踏板抖动,是影响驾驶员踏板脚感舒适度的主要因素之一。为此,以“无刷直流电机+二级减速器+齿轮齿条”作为助力源,开展了其踏板脚感抖动抑制研究。基于某踏板耦合式电动助力器,建立了其数学模型,通过对理想的踏板位移与主缸油压曲线进行分析,提出了一种电动助力器踏板脚感抖动抑制方法;在无刷直流电机三闭环控制的基础上,采用电机转角对助力器进行实时补偿的技术方案,并对电机转角补偿项进行了量化,设计了电动助力器踏板脚感抖动抑制算法;并在MATLAB/Simulink平台上搭建了该助力器的仿真模型,仿真结果验证了所提出的踏板脚感抖动抑制方法的可行性。研究结果表明,该方法不用增加任何附加成本,能够改善制动踏板脚感,降低制动主缸油压的稳态误差。

When the boosting motor of the pedal-coupled electric booster of an electro-hydraulic brake(EHB)system is under stall control,its torque pulsation easily causes the brake pedal to tremble,which is one of the main factors affecting the comfort of the driver’s pedal foot feeling.To this end,a system of"brushless DC motor+two-stage reducer+rack and pinion"was used as a power source to carry out the study the optimal control of pedal foot feeling.First,a methmatic model for the pedal-coupled electric booster was established.A jitter suppression method for improving the pedal foot feeling of the electric booster was proposed on the basis of analyzing the ideal pedal displacement and the pressure curve of the master cylinder.Then,Based on the three closed-loop control of the brushless DC motor,the technical solution of real-time compensation of the booster by regulating the motor rotation angle was adopted.The motor rotation angle compensation term was quantified,and a jitter suppression algorithm for the pedal foot feeling of the electric booster was designed.Finally,a simulation model of the booster was built on the MATLAB/Simulink platform,and the research results verified its feasibility.The simulation results show that the method can improve the brake pedal foot feeling and reduce the steady-state error of oil pressure in the brake master cylinder without adding any additional cost.