Research On Flow Field Simulation And Control Strategy Of Digital Change Valve

In order to promote the arrival of the industrial 4.0 era,the deep integration of digital technology and hydraulic transmission control technology is a very important direction of digital and intelligent manufacturing of traditional hydraulic components.Among them,digital valve is a new product with the combination of hydraulic technology,electronic information technology and digital control technology.it has the advantages of high resolution,small output error,convenient processing,simple structure,strong anti-pollution ability,no need for digital-toanalog converter,high control precision,direct control of digital valve through upper computer and so on.The work of this paper is to improve the spool structure in the development of digital reversing valve driven and regulated by permanent magnet synchronous motor.In order to realize the fast and accurate control of digital directional valve,the control strategy of permanent magnet synchronous motor(PMSM)is studied.The main contents of this paper are as follows:First,in order to make the digital valve designed have good response characteristics,to reduce the distortion of the valve core leading to the occurrence of valve core stuck,the structure of digital directional valve is improved,a new type of combined groove is designed as the throttle groove of the reversing valve core,internal flow field for improving digital commutation valve,uniform radial pressure distribution of valve core,the flow equation is derived from the analysis of the parameters of the throttle groove and the force of the valve core.Secondly,the model of the flow field inside the slide was set up with different opening sizes,building the overall model of the digital direction control system based on Solidworks.The internal flow field model is divided into different grids,and the simulation calculation is carried out based on Fluent.On the basis of the distribution of the flow field and temperature field,the Workbench was used to analyze the multiple field combination of the core,to make the pressure on the spool evenly distributed,the flow rate was deduced according to the section channel and the internal force of the spool was analyzed.Then,study the digital directional valve drive system(PMSM),establish the mathematical model of the drive system,in order to improve the response frequency and control accuracy of digital directional valve and the dynamic quality of its approaching motion,a sliding mode variable structure position loop controller for digital commutation valve drive system is presented based on improved exponential approach law and combined with optimal control and predictive adaptive law.Establishing the simulation model of digital directional valve on MATLAB/Simulink platform,the new controller designed is compared with the P control,study on the effectiveness of sliding mode variable structure controller with improved approach law for digital commutation valve drive systemFinally,a digital directional valve experimental platform is designed and built,the designed digital directional valve and its controller based on improved reaching law sliding mode variable structure control strategy are studied experimentally,verify its beneficial effect.