Research And Application On Experiment Of Mixed Sensitivity Method In Direct Drive Hydraulic Servo System

Because work condition and certain reasons often vary, there are many parameter variety and load interfere about the modern hydraulic servo system. Typical hydraulic servo system has been applied expensively in many fields such as space flight, national defense and many others industry because of its high power, fast response and high accuracy features. The direct drive electro-hydraulic servo system uses AC timing motor to replace electric-hydraulic servo valve, which is controlled by different pump's flux by changing the revolution speed of pump. The direct drive electro-hydraulic servo system which is much smaller, easier and energy saving is the perfect combination of them and taken as an important development direction of hydraulic servo system.Based on lots of correlative literatures and reference materials at home and abroad, this paper summarized the developments of the development of the robust theory and research progress and working principle of the direct drive electro-hydraulic servo system. The problem of H_∞theory used in the direct drive electric-hydraulic servo system is also introduced, especially the robust capability design. The mathematical model of AC servo motor and direct drive electro-hydraulic servo system is built in this paper. After building the H∞controller based on the mixed sensitivity method, this paper simulates the step and sine signals with different load and impulse interfere. In the process of designing the H∞controller, as the original model is a high-scale model, it is reduced to make the controller's scale little. The weight functions are chosen again and again in order to make the controller reach operation conditions and let the weight functions embody the system's performance.This paper simulates the H_∞control system with PID controller for the lack of quick reguilation. And aiming at robust stability, steady state accuracy and capability of anti-jamming, we take the experiments of the variable speed and load. It's considered that the H_∞mixed sensitivity method in the direct drive electric-hydraulic servo system can improve the accuracy of the system, and advance the capability of anti-jamming. By the result of the experiment, it is considered that the correctnesss of the theory analysis, and it achieves the desired objectives.