Design And Analysis On Electro-hydraulic Generator Of Spring Load

The general spring load is positive stiffness spring load. There is a kind of springload which has positive stiffness and negative stiffness as well. For the loading systemrelated with location itself，it will be unstable when it’s load object has negativestiffness load. This kind of variable stiffness spring load gives loading systemsignificant influence changed as the stiffness value and its replacement betweenpositive and negative. The influence makes the system under consistent responsespeed and control accuracy, even unstable.The study object is the electro-hydraulic generator of spring load which will beused to load the position control system with variable stiffness spring load. The studyis based on what kind of influence the variable stiffness spring load can make to thesystem and how feedforward control to kill the influence. Details are as follows:(1) An overview of the basic theory of force control system and the analysis ofcontrol theory of loading system related with position.(2) Creating a mathematical model of electro-hydraulic generator of spring loadbased on the physical model experiments required, and having got the mainparameters by designing calculate.(3) The simulation has been done by MATLAB/Simulink with which create thesimulation model according to mathematical model. Analysis that different positionand different stiffness value of load make a influence to the control precision、response speed and stability. The simulation verified the mathematical model finally.(4) In order to solve the problem of negative stiffness load makes the systemunstable, with the help of BP neural network, a control strategy combiningfeedforward control with PID control is proposed. The simulation gives a conclusionthat system after correction is stable, the response speed and control precision canmeet the requirements.Aimed at that load of loading system probably has positive stiffness or negativestiffness, this paper focus on problem of the system is unstable when its load stiffnessis negative. The synthesized control strategy is aimed to keep system stable as well as improve the control precision and response speed. It provides a new solution to solvethe problem that negative stiffness load make loading system unstable.