Research On The Nonlinearity And Control Method For The Proportional Valve Controlled Hydraulic Cylinder System

As an important branch of electro-hydraulic proportional control system, theproportional valve controlled hydraulic cylinder system now is widely used in industry,agriculture, military and other fields. Due to the median dead zone of proportional valveand the friction of hydraulic cylinder, the system is shown with severe nonlinearity, whichaffects the stability and precision of the control system. In order to improve systemperformance, the nonlinearity of the proportional valve controlled hydraulic cylindersystem is thoroughly researched through ways of theoretical analysis and experimentalmeasurements. And according to the nonlinearity, a dynamic compensation algorithmwhich can self-regulate the output is proposed to compensate for the adverse effects causedby the nonlinearity of the system. Finally, the effectiveness and superiority of the dynamiccompensation algorithm is verified through the comparative experiment on traditionalcontrol algorithms.The background and significance of the subject are introduced in chapter1and themain contents of the research are also included. In chapter2, the compositions andfunctions of each part of the system are described in detail and the mathematical model ofthe whole system is derived and established. Based on this model, the system performanceis analyzed. Chapter3is focused on the process of building the experimental platform forthe system. In chapter4the nonlinearity of the system and the causes are analyzed in depth.And the actual measurement of the nonlinearity is made in this chapter by computer testingsystem based on LabVIEW. In chapter5, the dead zone of the system is studied byanalyzing and summarizing the experimental results of the traditional PID controlalgorithms. On this base a dynamic compensation algorithm which can self-regulate theoutput is proposed to improve the control effects of the system. Finally, that this controlalgorithm can effectively improve the control system performance is verified through thecomparative experiment on traditional control algorithms.