| Electro-hydraulic servo valve is the integration of mechanical, electrical,hydraulic integration. It is used to achieve electrical and hydraulic signal’s conversionand precise control through a comprehensive combination of hydraulic technology,automatic control technology and high-tec manufacturing technology advantages. It isthe core element of electro-hydraulic servo control system, its performance directlyaffect and deternine the entire automatic servo control system’s performance.Dual-nozzle-flapper servo valve has some advantages of fast response, good linearity,small dead zone, compact structure, the entire valve performance to calculate andforecast, etc.. It has good static and dynamic characteristics which used most widely inthe industry.For better frequency response and stability performance, it is necessary tooptimize the servo valve to further improve its performance in order to meet highcontrol requirements of increasing engineering applications. This provides a referenceand provenance for optimization of the servo valve basis, and has certain practicabilityin in engineering.In this paper, the object of study is the domestic Dual-nozzle-flapper servo valve.First of all, the working principle of double servo valve was introduced, and then themathematical equations of all sub-segment of Sevo valve are deduced in detail, finallymathematical model and the overall transfer function of the Dual-nozzle-flapper Servovalve are recieved. In order to analyse the design parameters with practical engineeringsignificance easily, the overall transfer function of Dual-nozzle-flapper Servo valvehas been simplified.In the study of Dual-nozzle-flapper Servo valve, the six parameters are selected tobe optimized. According to the optimization object of frequency response and stabilityperformance, parameter optimization model of servo valve is constructed. Chaosparticle swarm optimization is used in the optimization model, the dynamic parametersof servo valve are optimized, and a set of optimized data derived. By comparingsimulation analysis on the data before and after optimization, the effectiveness of theoptimization model and optimization method are verified. According to the optimizedparameters, servo valve internal structure parameters and parts specific size aremodified to improve the servo valve performance. The optimized data indicate good practical value in engineering.A simulation platform for the servo valve was built by Simulink modules in the background of Matlab software. Based on the simulation platform for servo valve, the comprehensive dynamic parameters of servo valves are in simulation study. Analysis the relationship between the four comprehensive dynamic parameters Ksv、Wmf、Kvf、 gmf and the dynamic characteristics of servo valve, some conclusions are drawn:(1) To increase the servo valve flow gain Ksv, the response speed of the closed loop system is improved. Appropriate to reduce the lever stiffness Kf, the dynamic performance of the servo valve and the stability of the system are improved.(2) Under the guarantee of stability margin precondition, it is an effective way to improve the dynamic characteristics of the performance of the system by increasing Kvf.(3) Increasing the natural frequency Wmf, dynamic performance and steady-state performance of the system are improved.(4) It can enhance the stability of the entire system and obtain a satisfactory dynamic performance by setting desired damping ratio.(5) Using an integrated dynamic parameter as optimization objective for improving the dynamic performance of the valve, we need to simultaneously restrict or limit other comprehensive dynamic parameter in order to reducing their effects on the entire valve performance. |
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