Research On Design And Control Of Spring Fatigue Test Bed Based On Electro-hydraulic Servo

The electro-hydraulic servo springs fatigue testing machine is the most popular equipment in springs fatigue test. The function of the testing machine lies on the hydraulic system and control system’s character. Electro-hydraulic system integrates with the characteristics of electrics and hudraulic press aspects, and has many advantages such as high control precision, fast response speed,big output power,disposing signal agilely, and achiecing various parameters’ feedback easily and so on.The text starts with the design of hydraulic servo system, based on the long-time and consecutive work characteristics of the fatigue machine. Elastic load due to the system, the cylinder valve-regulated generation of elastic load in the load characteristics analysis focus. This paper calculates the hydraulic pressure power parts’ parameters according to the load optimum matching, selects the hydraulic elements’ models and builds the models of the hydraulic system by using the transfer functions. Then the paper does the dynamic analysis and simulation about the hydraulic system and gives the related evaluation parameters.However, with the increasing of control quality request, the control accuracy and robustness of the normal PID decrease. That decided mainly by the typical unknown and uncertain nonlinear system of electro-hydraulic servo system, which gains precise maths model of system difficulty. Though the maths model can be set up, its model is always so complex that it makes the analysis, design and practice of the traditional control method baded on precise maths model more difficult. This paper designed an fuzzy controller based on genetic algorithm is presented that integarates fuzzy control with GA well, which remedies a kind of rough method that usually confirms the subjuectong function according to experiences.A simulation model of typical system is realized successfully with MATLAB. The result of simulation compare with the result of PID and fuzzy show that the controller has improved dynamic and static performance of control system and has obtained good control quality. That is to say, this control method is effective on this system.