Study On Dynamic Characteristic Of Electro-hydraulic Control Valve Based On DSP

As one of the most important unit in the field of industrial automation, the control valve is mainly used in controlling of pipe network systems in petrochemical, power station, metallurgy, shipbuilding, nuclear industry, aerospace and other industries. With the rapid development of science and technology, the demand of the high performance control valve is bigger and bigger. In the modern, the most part of the high performance control valve’s market is occupied by foreign countries. In order to break the foreign countries’ monopoly and meet the demand of industrial’s development, it is imminent to study the high performance valve with an independent intellectual property rights. With the support of the national "863 project" and the special fund for the doctoral program in colleges and universities "big flow control valve of high frequency power field coupling vibration and leakage from the perception mechanism study",this paper carried out the following research work according to the above problems:First of all, based on the function of the intelligent control system, we developed the control valve’s intelligent controller with the core of DSP technology. The study of the controller realized the LCD display, data acquisition, servo motor’s drive, temperature and humidity testing and other functions. The design of hardware circuit was completed in the software of Altium Designer and the compiles and runs of main programs and department programs was completed in the software of CCS.As to the electromagnetic interference problems, we put forward some concrete improvement measures in the design of hardware and software.Secondly, we designed a direct drive volume control electro-hydraulic actuator which combined the electronic control technology and hydraulic transmission technology. We designed the mechanical structural of the actuator. And then we calculated and selected the relevant components. Lastly, we put forward some improvement measures for the purpose of reducing the vibration and noise that produced by the actuator. Finally, we set up a simple experiment platform combined the controller part and the actuator. We carried out the experiment about the simulated experiment set of valve opening, the results shows that the effect is very good.Thirdly, based on the structure of the control valve actuator, we established the mathematical model on the parts of servo motor, pump control cylinder system and valve. And Then, we deduced the system transfer function according to the mathematical mode aims to established the relationship among valve opening, valve load, and flow. According to the MATLAB BODE diagram criterion, we could concluded that the stability margin is big and the system stability is good.Finally, we proposed an optimized fuzzy PID control strategy combined the fuzzy control strategy and PID control strategy in this article. In the strategy, we used the PSO algorithm to improve the fuzzy control rule made by the experts based on the experts’ experience. Aims to make the rules can be adapted to the control system through the improvement. And then, we set up the simulation model under the control’s type of PID control strategy and the improving fuzzy PID control strategy in the simulink module of MATLAB aims to study the dynamic and static characteristic of the system. The simulation results show that:when the system is controlled by the improved control strategy,, the system’s step response ability is more quickly,the system’s overshoot amount control is better, the waveform tracking performance is more excellent and the anti-jamming performance is more stronger compared with the traditional PID control strategy. That makes it can be more suitable for using on the controlling of the high performance valve.