Control Strategy Of The Automotive Road Simulator For Waveform Replication In Time Domain

In the fatigue test of automobile parts, the laboratory road test simulator can highly simulate the actual vehicle vibration environment for auto parts, and shorten the test period.This paper use the vertical hydraulic road simulation system,based on single channel,as the experiment platform, in consider of the nonlinear factors in the hydraulic control system,to analysis and study of the influence on the servo control, at the same time,combining time-domain identification and iteration control waveform replication technology, eventually to improve the accuracy of waveform replication in the time domain for target spectrum signal of auto parts in road simulation platform. This paper fully consider the influence of the nonlinear friction factors on the servo control strategy and the identification and iteration strategy, mainly accomplished the displacement spectrum signals and acceleration spectrum signals identification and iteration control strategy.First of all,this paper modeled the single channel hydraulic servo control system in theory, analyzed the characteristics of valve-controlled unsymmetrical cylinder mechanism. on the closed-loop servo control strategy, to expand the closed loop bandwidth,the paper compared the characteristics of the proportional control strategy with the three state control strategy,which designed by root locus method.Secondly, the paper analyzed the synthesis method of auto parts target road spectrum signal,considering the indicators,power spectral density of the spectral signals and amplitude.This paper set up a hydraulic servo control Matlab/Simulink nonlinear time domain model, analyzed the influence of stribeck model friction and random disturbance on the hydraulic servo control strategy, verified on repetition limitations of servo control strategy in the target spectrum signals waveform replication.Then, this paper mainly focused on the study of time domain waveform replication control strategy,which combined frequency response function identification and driving signal off-line iteration. In the case of fully considering the system identification accuracy, the iterative correction for acceleration signal spectrum are susceptible to nonlinear system friction factors,this paper put forward the improved the spectrum iterative way, enhance the iterative precision of the acceleration spectrum signals.Finally, according to the requirements of the automotive road simulated load,this paper completed hydraulic parts, mechanical structure and control system design on the road simulation test platform,and real-time software development based on rapid control prototyping,and then completed experiment of the servo control strategy and identification iteration strategy for waveform replication of the target spectrum signals.