Characteristic Analysis And Applied Research On The Hydraulic Differential Cylinder Controlled By Variable Speed Pump

This research is derived from the project assisted by nation nature science found, the research objectons are low cycle fatigue testing machine and hydraulic press. For the large exhausting shortage of cycle fatigue testing machine and the control way shortage of hydraulic press,put forward to employ variable speed pump control hydraulic differential cylinder system, aiming at economizing energy in low cycle fatigue testing machine and improve control in hydraulic press. In the research load characteristic proceeding of testing machine and hydraulic press are studied, and the variable speed pump control electro-hydraulic system is designed according to the load characteristic and the traditional hydraulic control way . The control principle of the servo motor and the process of setting up model are introduced in detail in the thesis, and the accuracy of the motor model are verified by contrasting with experiment data of motor. In the thesis the model of variable speed pump control electro-hydraulic servo system is setted up, the fatigue testing of testing machine and the constant speed rate control of extruding pole in aluminum extruder aresimulated, the simulation result shows that the variable speed pump control electro-hydraulic system can operater in four quadrants in low cycle fatigue testing machine and control the position of extruding pole, attaining the prescriptive accuracy request. In the thesis the indetermination parameters influence testing are analyzed and simulated, some important conclusions are getted. The research provide a kind of new control project to testing machine and hydraulic press , will impel actively variable speed pump control system to be emplyed in production ,has the important theories meaning and the useful value.