Research On Rectangular Control Strategy For Wheel Coupled Road Simulation System

The wheel-coupled road simulation platform is one of the most widely used vehicle fatigue testing equipments.The electro-hydraulic servo control system drives the exciters to excitate load,for the purpose of simulating the vibration environment practically.Due to the non-linearity of the system,iterative control needs to be adopted to ensure the accuracy of the control.In some cases,more control accelerometers are hoped to be add so that can measure the datait of some other key points or describe the vibration state of the load more specifically.In such circumstances,the output amount of the system is more than the input ones,and it is called rectangular control.This paper mainly research on the rectangular control strategy for wheel-coupled road simulation system.First,model the vehicle load and servo system of the road simulation platform.Using a certain type of vehicle as a load,perform the kinetic analysis and establish a 7-DOF vehicle vibration prototype of passive suspensions.By Simulink,analyze the dynamic and coupling characteristics;then,model the entire electro-hydraulic servo position-control system considering the load,and correcting the model based on its closed-loop FRF and system requirements,so that the system can meet the control requirements.Ultimately,get the actual transfer function matrix of the system.Secondly,research on the identification methods.Including the conversion method of the signal between time domain and PSD.Adopt and compare 4 typical non-parameter identification methods by Marlab;the multi-channel system uses simultaneous excitation method to identify,estimate the FRF matrix of the entire system,at the same time,analyze the causality between all input and output signals to obtain the coupling characteristics through the coherence function.Finally,research on the iterative control algorithms.Since the rectangular control is used to solve the driving signal by solving the inverse of the FRF matrix,it involves the transcendental equations,and there is no accurate answers.How to ensure the rapidity and convergence of key points in the iterative process is the focus of this paper.In this chapter,obtain the reference signal through road roughness,and then based on the RPC algorithm,calculate the impedance function based on the generalized inverse to correct the drive signal.Then study the influence of the step size selection on the system's rapidity and the weight coefficients of the error spectrum and the RMS error on the key points' convergence.Through simulation and verification by adjusting different parameters,the research on the rectangular control strategy of wheel-coupled road simulation was conducted.