| The high-speed CNC punch press has been widely used in the automotive industry, the fabricated metal products and aerospace industry, which has great advantages of high frequency, low noises, good stabilization, adjustable speed and stroke, alterable stamping force, adapting to many stamping technique and so on. As an important part of the CNC punch press, the high-speed punch press hydraulic system must have good stability and nice static and dynamic response property. However, there are many problems such as the vibration and hydraulic shock while the hydraulic system has being started and reversed, instability due to the external disturbance, which greatly affected the stamping accuracy of the punch press. In view of these problems, the hydraulic servo-control system of high-speed CNC punch press has been studied.Firstly, the dissertation reviews the current status and development trends of the CNC punch press and hydraulic simulation technology at home and abroad, introduces proportional servo-control technology and its application. Then, expounds the composition and hydraulic system working principle of the 300kN CNC high-speed punch, analyzes situation of the rapid advance phase, the working phase and the rapid return phase. Also, the parameters of the hydraulic components has been introduced and checked. Based on the AMESim software, the simulation model of high-speed punch hydraulic system is established. The dynamic simulation is carried out in two working conditions with the working stroke are 10mm,50mm respectively. The simulation results show that the frequency of the system can satisfy the technical requirements, but also there are hydraulic shock and pressure jump while the system is started and reversed.The mathematical model of the proportional servo-valve controlling asymmetrical cylinder hydraulic system is built, basing on the servo-valve flow equation, the flow continuity equation of hydraulic cylinder and the force balance equation of hydraulic cylinder and loads. Considering the influence that different working condition to the hydraulic system parameter, the transfer function is respectively identified in the situation of the fast down phase, the working phase and the rapid return phase.The control strategy in different working conditions is studied after obtaining the system transfer function. The PID control theory is used to the hydraulic system. Also the PID controller is designed and the PID parameter is received by critical proportioning method. Simulation results of the PID control indicate that the velocity of the hydraulic cylinder is steadier, the shock and vibration of the system is reduced, the dynamic performance of the system is improved.Also, the fuzzy control strategy for the hydraulic system has been studied. The fuzzy rules have been built and the fuzzy controllers have been designed. By apply of Simulink tools, the simulation results show that fuzzy control can increase stability and anti-jamming capability of the system.
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