Research On Multichannel Electrohydraulic Servo Control System Of Automobile Components' Fatigue Test

Fatigue failure often happens on the vehicle that under pressure and tension while it'sdriving, so a qualified automobile has to pass the fatigue test on components and entire car.To complete the fatigue test, a fatigue testing machine which can load waveform to thesystem, have a high accuracy and ability on data collection and analysis is needed. Thedevelopment of computer technology and hydraulic servo control technology makeselectrohydraulic servo control system computerization possible, it simplifies the systemstructure, makes the operation easy and saves the cost on controller's purchasing. With theimprovement of living standard in these years, people's demand on automobile's safety isbeyond its transportation capacity, then the test on automobile component's static, dynamicand fatigue property shall be stricter. This research and design on control system ofmultichannel electrohydraulic servo fatigue testing machine is based on the above ideas.Primarily, consult the related information to understand the research status indomestic and overseas, the electrohydraulic servo control's principle and basiccharacteristics as well. According to the comparison result of several traditional fatiguetesting machines' analysis, choose electrohydraulic servo control as control strategy.Design the system's parameter and function that matches the requirement.Secondly, theoretical analyze the valve control system, establish its mathematicalmodel, derivate the pressure-flowrate formula and the load balancing formula, determinethe type of hardware. To make an accuracy control of system, research a PID controlalgorithm based on BP neural network in foundation of regular PID control. The MATLABsimulation result shows that the neural network can do a more accuracy control and aninstant online adjustment.Use NI LabVIEW software to control the waveform and design the data collectioninterface, choose board card PCI8324AF and data acquisition card RM4018i as hardware toconvert A/D and D/A signal. Disassemble control system into a series of tasks by the method of modular programming, match every task a VI, combine these VI into a packageto complete the control system and make its operation interface simple.Lastly, install then debug the system after every part's design has completed. Thetesting result shows that the control of system and the data collect then analyze can reachthe anticipation.