| Electro-hydraulic proportional control technology has been widely used in modern industry,aerospace,military and other fields.Among them,electro-hydraulic proportional valve,as an important hydraulic component,because of its low price and superior performance has attracted more and more attention The space for development is also increasingly widespread.Proportional valve center position control performance will directly affect the performance of proportional valve.Therefore,according to the characteristics of the structure and parameters of the proportional valve,it is of great practical significance to study the corresponding valve center position strategy to improve the actual working performance of the proportional valve.This paper focuses on the proportional valve center position control strategy,the main work summarized as follows:1.The valve body and valve center structure of proportional valve were analyzed and threedimensional modeling was completed.The changing mode of the flow channel during the valve center movement was understood,and the corresponding channel was intercepted as the research object,and the corresponding three-dimensional model was imported into Fluent for the numerical analysis.The variation of throttle flow field and the hydrodynamic force of the valve center under different opening degrees were analyzed.The static flow characteristics of the orifice were obtained by simulation,and the pressure loss analysis was carried out according to the flow channel situation of the actual test bench.The flow characteristic curve which was consistent with the experimental results was obtained.2.The dynamic model of proportional valve center position control was established in the Simulink.The simulation and experimental results under pid control mode were compared to verify the accuracy of the model.At the same time,the dead zone of zero position control was found in the valve center position control.The cause of dead zone in the vicinity of zero position was analyzed by simulation,and the influence degree of different influencing factors of the valve core position control on dead zone time in the vicinity of zero position was analyzed.3.Through the analysis of the valve structure,it was found that the dead zone was mainly caused by the spring installation mode,and the influence of system parameters on the dead zone time length was further analyzed by simulation.The control strategy and watershed simulation results were verified and analyzed on the static pressure test platform,and the reliability of the simulation results was determined.It could effectively improve the control effect of proportional valve center at zero position and effectively increase the frequency width of valve core response.4.According to the causes of dead zone of valve center zero position control,a position step compensation strategy based on pid control method was proposed to improve the performance of valve center position control,and the response characteristics of several different control methods were compared.And the influence of different control methods on the frequency response of proportional valve under different input amplitude.5.The control performance and frequency response characteristics of different control strategies were tested on the static test platform of proportional valve.The comparison showed that the position compensation control could effectively reduce the dead time,improve the control effect of proportional valve center at zero position and increase the response frequency of the system.Finally,the main research work was summarized,and the future research work was prospected. |
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