Research For Hydraulic Servo Pressure Control System Of Metal Ceramic Loading Test Device

Metal ceramic composites have been widely used in engineering practice because of their high strength,high hardness,abrasion resistance,corrosion resistance and good toughness and plasticity,however,it is necessary to load the shock test after the sintering process to improve the compactness and mechanical properties of the materials.For this purpose,a special hydraulic servo pressure control system is designed to provide high frequency high-precision and stable impact load for the loading test device.Therefore,it has certain theoretical research significance and engineering application value.At first,the paper discusses the current status of the research on the valvecontrolled asymmetric cylinder,most of which do not consider the load spring stiffness,however,the load spring stiffness exists in some cases,such as the loading test of Cermet composite.Therefore,based on the principle of power matching,the load pressure and load flow are redefined,the mathematical model of the valve-controlled asymmetrical cylinder is established by the flow continuity equation and the force balance equation in consideration of the load spring stiffness and the hydraulic spring stiffness,and the model is simplified.Aiming at the difficulty of low pressure fluctuation and high frequency requirement of hydraulic servo pressure control system,and the characteristics of large range and nonlinearity of hydraulic parameters,the paper adopts model reference adaptive control method and designs adaptive controller to improve the precision and robustness of pressure control.In this paper,the Model Reference Adaptive Control strategy based on the hyper-stability theory and the conventional PID control strategy are simulated and compared with the parameter determination and uncertainty two.The results show that the model reference Adaptive controller has better control performance than PID controller,regardless of whether the parameter of the system is determined or not,and the design requirements of the metal ceramic composite loading test device are fully achieved.