| This paper supplied a new way through variable frequency variable speed (VFVS) to change its output flow rate and adding a constant-pressure-drop valve , which could solve the defects in hydraulic pressure servo control system, such as low efficiency in control system, short life, poor ability in resisting pollution, low efficiency in driving system and flow rate, pressure pulse. And this way was proved to be effective.In chapter 1, the application and developing trend of speed control of hydraulic pressure system is discussed. The significance and foreground of applying VFVS technology in the hydraulic pressure system is demonstrated. The content and technical method used in this study is introduced at the end of the chapter.In chapter 2, the configuration of the system is presented. Every part of the system is briefly discussed and lay foundation for the proceeding analyzing and studying.In chapter 3, the pressure pulse under the two situations of the system with and without damper is discussed at the basic of analyzing the flow rate pulse. Then the conclusion that the system has filtering effect is drew after adding a damper init, but its serious in power wastage because of adding a damper.In chapter 4, the principle drawing of the system is presented after adding a constant-pressure-drop valve. The operating principal of the valve is briefly introduced. The static mathematical model is built up and study is carried out by means of simulation under the circumstance of MATLAB, then the static working point is obtained. Based on the nonlinear model, the dynamic characteristic is simulated, by considering the influence of the environmental and geometrical factors, such as oil modulus, chamber volume etc.In chapter 5, the dynamic mathematical model of the whole system is constructed considering the influence of VFVS electrical motor. The dynamic characteristic is simulated, by considering the influence of the parameters.Chapter 6 is the summarization and prospect. |
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