The Design Of Electro-hydraulic Servo System Based On DSP

The CNC turret punch as a sophisticated equipment of panel processing has arousing the attention of the people in recent years. At present, in our country the core parts of the CNC punch's motive force—high-speed hydraulic servo control system what have always been dependent on imports. So we need to develop the high-speed integrated hydraulic servo system with independent intellectual property rights imperatively.The electro-hydraulic servo control system which is used in the high-speed CNC punch is studied in this paper. The system mainly uses the hydraulic cylinder to drive the head hit and uses the electro-hydraulic servo valve to control stamping. The hydraulic system's structure is compact and simple. The servo controller uses industrial grade TMS320LF2407 DSP chip which is product by TI company and the control algorithm adopt neural network PID control algorithm, so whether in the control accuracy and control speed and other aspects have a rapid development. The stamping speed can be reached at 1000 times/min, and the rated working pressure can be reached to 20 tons. Secondly, because the system uses closed-loop control and the journey of the hydraulic cylinder can be regulated arbitrarily, so it can regulate molding mold by controlling the punch's stroke and easy to use.Firstly, the dissertation introduces the development process of the main drive system of the CNC turret punch, and then describes the backgrounds of the subject, the status and trends of the CNC machine tool industry development at home and abroad. This problem looked up a large number of domestic and foreign relative literatures to confirm the design scheme which is achieved the control of the stamping by electro-hydraulic servo valve. The electro-hydraulic servo-valve have many advantages such as quick response, high control precision and so on. Consequently, they are widely used in the high-speed, high-voltage, high-frequency control systems.According to the scheme design of the system, we select the main hydraulic components and establish a mathematical model of the hydraulic system. The purpose of the establishment of the mathematical model is in order to simulate conveniently. The simulation study can know the dynamic properties of the hydraulic system, and provide a theoretical basis for improving and perfecting the system's control performance. This paper firstly determine a mathematical model of the electro-hydraulic servo valves, and according to the flow equation of the hydraulic cylinder and the motive equations of the piston to establish a mathematical model of the valve control cylinder. Finally, get transfer function of the hydraulic servo system .Electro-hydraulic servo control system is controlled by the digital components and the digital controller is the core component of the whole control system. The control quality of the whole system depends on the control algorithms which is adopted in the procedures. To ensure the realization of the control algorithm, we choose DSP as the core of the controller. The whole system's hardware includes A/D and D/A module, power module, module of the power conversion, JTAG interface module, memory module and SCI asynchronous serial communication module.The electro-hydraulic servo system which is studied in this paper belongs to typical non-linear control system, it is difficult to achieve favorable control effect by use of the conventional PID control algorithm. Accordingly, this paper choose neural network PID control algorithm, it can change the three parameters of the PID online through self-learning function ,it also can achieve good control effect in non-linear control systems.Finally, by use of the mathematics model of the hydraulic servo system and neural network PID control algorithm, to perform the dynamic simulation on the basis of the Matlab tool software and give the simulation results and analyze it. Through the simulation, you can clearly see the neural network PID control algorithm in terms of both stability and rapidity have been greatly improved to meet the system's performance requirements.