Research On Digital Electro-hydraulic Proportional Control System For Large Size Valve

Valve drive device occupies an important position in industrial manufacture automatization. With the maximization of valve and automation of industrial process, the control performance requirement of diverse valve drive device becomes higher and higher for all walks of life. Electro-hydraulic proportional control technology has been widely used in valve drive control and industrial manufacture, for its high precision, quick response, small volume and large output force.For the proportional control of drive device used in large size valve, and on the basis of research of digital electro-hydraulic proportional control system, this paper propose the structure and composition of the digital electro-hydraulic proportional drive device for large size valve. Both nonlinear model and linear model are established. Utilizing AMESim simulation software, impact of different structure and parameters are analyzed to optimal design. And the drive device based on digital electro-hydraulic proportional control system for large size valve is developed. Through related experiments to verify the simulation results, the theoretical analysis and experimental results show that digital electrohydraulic proportional drive to reach the design requirement.Contents of each chapter lists as follows:In chapter1, on the basis of the analysis of materials from home and abroad, the principle, composition of electro-hydraulic proportional control system are introduced as well as the typical electro-hydraulic proportional position control system. For the proportional control of used in large size valve drive, the status of large size valve in industrial production and part-turn rotary drive device are analyzed and summarized. Then, some typical digital valve and rotary valve are introduced. At last, the significance and contents are mentioned.In chapter2, the structure and composition of proposed digital electro-hydraulic proportional control system are proposed. The input is the specified value of valve, and to ensure that the opening degree of the valve can follow the input is the control objective. This chapter gives the overall structure and principle design of digital electro-hydraulic proportional control system, then introduce the structure and principle of each constituent modules. At last, key components are verified.In chapter3, through a comprehensive study of digital electro-hydraulic proportional control system, both nonlinear model and linear model are established. And with the AMESim system simulation software, we finished modeling, simulation and analysis to explore the impact of different structures and parameters to system characteristics, and optimize the design.In chapter4, the method to complete the electrical control system structures, software and hardware design based on Siemens S7-200is expounded, after debugging, the electrical control system can meet the control requirements of the system.In chapter5, based on the theoretical and simulation analysis, the full set of digital electro-hydraulic proportional drive device for large size valve are completed. Then a test system is built to finish the performance test. The comparative analysis of experimental data and simulation results presents a high degree of consistency, and verify the correctness of the theoretical analysis and simulation model. In addition, it means it is practical to apply the digital electro-hydraulic proportional control system to proportional control of large valve.All achievements of the thesis are summarized and the further research work is put forward in chapter6.