The Design And Research On Control Technology Of The Large-flow Cartridge Electro-hydraulic Servo Valve

With the development of industrial application of electro-hydraulic servo system, the requirements of electro-hydraulic servo system and electro-hydraulic servo valve is higher and higher. As in the high-frequency electro-hydraulic loading test bench, large output force and high frequency is required. The electro-hydraulic servo valve must have the characteristics of high-pressure, high-frequency and large-flow rate at the same time. In order to satisfy the requirements of electro-hydraulic servo valve, such as large-flow and high-frequency, a large-flow cartridge servo valve with the function of three position four-way is designed, and the performance of it is studied. The main content is followed as:Firstly,the reason of the contradiction between large-flow and high-frequency of the electro-hydraulic servo valve is brief analyzed, and the design idea of large flow servo valve is put forward. Based on this, a large-flow cartridge servo valve with the function of three positions four-way is designed, and its composition and working principle is analyzed. Based on the structural characteristics and the working principle of the pilot servo valve and the main valve, their AMESim simulation model and the servo valve simulation model is establishedSecondly, the control performance of the single cartridge two-way servo valve is analyzed, and the research on the influence of the quality of the main valve spool,the working pressure of pilot valve and the disturbance to the main valve on the response of the cartridge two-way servo valve is made by simulation. According to the analysis and simulation results, The hybrid control scheme consisting PID controller with velocity feedforward and disturbance observer is proposed. The simulation results show that, under of control of the hybrid controller, the single cartridge two-way servo valve has high accuracy and high dynamic response, and it can satisfy the performance requirements of the large-flow cartridge electro-hydraulic servo valve.Thirdly, the influence of the synchronization between the double valve on the dynamic performance of the servo valve is analyzed. In order to solve the non synchronous and improve the synchronization of the double valve, a synchronous control strategy based on the synchronization error of double valve cross-coupled synchronization fuzzy control is proposed. The simulation results show that, the double valve has good synchronization and high dynamic response at the same time with the synchronous controller.Lastly, the static state and dynamic state performance of the large-flow cartridge electro-hydraulic servo valve is tested by simulation. The static state characteristics include flow characteristics with load, flow characteristics without load and internal leakage characteristics. The dynamic state characteristics include step response characteristics and frequency response characteristics. The results show that the static state and dynamic state performance of the servo valve can satisfy the design requirements and this will be a good contribution to further research of electro-hydraulic servo valve.