基于盘-块面弹簧接触的动力学模型的制动抖动分析

Brake Judder Analysis Based on Dynamic Model of Disc-pad Spring Contact

考虑制动盘-块间采用面弹簧接触方式建立一种6自由度制动系统动力学模型,推导出对应的动力学微分方程,并且构建Simulink模型。采用抖动"故障盘"的端面跳动SRO(surface run-out)与薄厚差DTV(disc thickness variation)的叠加位移曲线作为系统输入,仿真得到制动压力波动BPV(brake pressure variation)与制动力矩波动BTV(brake torque variation)时域响应。然后,分别以抖动"故障盘"的实测DTV曲线、SRO曲线以及SRO与DTV的叠加曲线作为仿真的输入,对比台架试验结果与3种不同输入下的仿真结果,以验证所构建的盘-块面弹簧接触动力学模型的正确性以及模型仿真输入改进方法的正确性。接着,通过改变台架试验以及仿真过程中的制动液压,研究制动系统的初始制动液压对制动压力波动BPV与制动力矩波动BTV时域响应的影响。最后,以台架试验结果作为基准值,将单点接触模型的仿真结果与所提出模型的仿真结果进行对比。结果表明:采用SRO与DTV的叠加曲线作为仿真的输入所得到的仿真结果与台架试验结果更加吻合,制动系统的初始制动液压力对制动力矩波动幅值的影响很小,所提出的动力学模型在预测制动抖动方面具有更高的准确性。

In this paper,a 6-DOF dynamic model of brake system was established by considering the contact mode of face spring between brake disc and brake pads.The corresponding dynamic differential equation was derived and the Simulink model was constructed.The superposition displacement curve of SRO(surface run-out)and DTV(disc thickness variation)of"fault disc"was used as the system input,and the time-domain response of BPV(brake pressure variation)and BTV(brake torque variation)of different brake pressure were simulated.Then,taking the measured DTV curve,SRO curve and the superposition curve of SRO and DTV as the simulation input,the simulation results of bench test and three different inputs were compared to verify the correctness of the built disc-pads spring contact dynamics model and the correctness of the model simulation input improvement method.Then,by changing the brake hydraulic pressure in the process of bench test and simulation,the influence of the initial brake hydraulic pressure on the time-domain response of BPV and BTV were studied.Finally,the simulation results of the single point contact model were compared with the simulation results of the proposed model.The results showed that the simulation results obtained by using the superposition curve of SRO and DTV as the simulation input are more consistent with the bench test results.The initial brake fluid pressure of the brake system has little effect on the amplitude of brake torque fluctuation.The dynamic model proposed in this paper has higher accuracy in predicting brake judder.