| Digital hydraulic technology and application in aerospace hydraulic servo control system,the two is the world’s most advanced hydraulic technology.Compared with the traditional servo valve control hydraulic cylinder,the digital hydraulic cylinder has the advantages of simple structure,strong ability of anti-pollution and anti-interference,and low production cost and wide application space.The purpose of this paper is to study the stability,stiffness,response and accuracy of the digital hydraulic cylinder.First of all,a large number of literatures are reviewed,and the structure of four types of digital hydraulic cylinders are analyzed and compared.Then,the structural parameters of the digital hydraulic cylinder are determined,and the complete mathematical model is established.The simulation model is established by using two kinds of simulation software,Matlab and AMESim.In the time domain and frequency domain respectively simulated spool area gradient,median pre opening quantity,the movement of the spool amplitude,supply pressure,feedback factor nut lead,the amplitude of input signal to the digital hydraulic cylinder stability,stiffness characteristics,response and accuracy.Study on stability of digital hydraulic cylinder.The influence rule of the three main parameters,including the area gradient of the spool and the amplitude of the motion and the opening of the center,on the stability of the digital hydraulic cylinder.The smaller the spool area gradient,the greater the spool movement amplitude,the valve opening is open,the better the stability of digital hydraulic cylinder.Research on stiffness characteristics of digital hydraulic cylinder.In this paper,the influence of four structural parameters on the stiffness of the digiteal hydraulic cylinder is studied,including the valve core area gradient,the middle position of the screw nut and the oil pressure.There is no relation between the valve core area gradient and the stiffness,the smaller the opening of the middle,the greater the lead screw nut and the greater the pressure,the greater the stiffness of the digital cylinder.Study on response characteristics of digital hydraulic cylinder.In this paper,the influence of structural parameters such as spool area gradient and signal amplitude on the response characteristics of digital hydraulic cylinder is studied.The smaller the area of the spool,the smaller the signal amplitude,the faster the response of the digital hydraulic cylinder.Accuracy study.In this paper,the influence law of the helix angle on the control precision of the digital hydraulic cylinder is studied.The study found that the ball screw helix angle in the 10.61°～24.45°,good accuracy of the digital hydraulic cylinder.,good accuracy of the digital hydraulic cylinder.Study on characteristics of digital hydraulic cylinder driven by pressure feedback device.This paper also establishes the mathematical model of digital dynamic pressure feedback hydraulic cylinder device,the dynamic pressure feedback device was designed.The structure parameters of the study found that dynamic pressure feedback digital hydraulic cylinder device can not only improve the system stability and dynamic stiffness of the system is not reduced.In this paper,the research results of digital hydraulic cylinder,for the future development of digital hydraulic cylinder has some theoretical significance. |
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