Research On The Simulation And Optimization Of Electro-hydraulic Poppet Valve For Tractor

As the core control components of the electro-hydraulic poppet valve for tractor,the proportional lift valve and the proportional lower valve control the inlet and outlet flow of the lifting hydraulic cylinder in the tractor hydraulic suspension system to achieve tractor tillage depth control.The performance of the two valves directly determines the performance of the tractor hydraulic suspension system.Therefore,the simulation and optimization research of proportional lift valve and proportional lower valve has important practical significance.In this paper,simulation and optimization algorithms were used to optimize the valve based on the impact of various structural parameters of the valve on its static and dynamic performance.The main research content of this article is:(1)The structure and working principle of proportional lift valve and proportional lower valve were analyzed,and their static and dynamic constraint equations were written.According to the static force balance equation of the valve core and the static flow continuity equation of each chamber,a static simulation model of the valve was established in Matlab to solve its static characteristics;The differential equation of valve spool motion and the dynamic flow continuity equation of each chamber were converted,and a dynamic simulation model of the valve in Matlab Simulink based on the conversion formula was established.(2)By establishing a three-dimensional simulation model of the flow field in Fluent,the steady-state hydrodynamic values of the proportional lift valve and the proportional lower valve under different valve opening degrees and pressure differences were calculated,and an interpolation model between the valve opening steady-state hydrodynamic forces and the valve opening degrees and pressure differences was obtained based on this;At the same time,through Fluent simulation calculation,the equivalent flow area fitting formula for different valve opening degrees was obtained.This provides accurate steady-state flow force and flow area parameters for static and dynamic simulation models.(3)Based on the static simulation model of the proportional lift valve,this paper calculated the percentage of effective control current to rated current of the solenoid for different parameter combinations,and identified the parameters set with the highest percentage as the optimal static characteristic;The dynamic performance of the proportional lift valve was optimized based on genetic algorithms using the ITAE integral criterion as a fitness function.Using the target rated flow rate of the proportional lower valve as a constraint condition and the ratio of the dead zone current to the rated current of the electromagnet as a fitness function,a set of parameters with the best static performance was optimized using genetic algorithms,and the optimization direction of each parameter was qualitatively analyzed through dynamic simulation.Finally,the final optimization parameters of the proportional lower valve were obtained by comprehensively considering the static and dynamic performance.(4)A static and dynamic performance testing platform for proportional lift valve and proportional lower valve were established,and the static and dynamic performance of the valve after parameter optimization were tested.The results are basically consistent with the optimized simulation results,verifying the correctness of the simulation model and the effectiveness of optimization.