Research On Robust Control Applied To The Electro-Hydraulic Load Simulator

The electro-hydraulic load simulator is a typical kind of passive force control system. It's applied to simulate all kinds of loads on rudder under laboratory conditions, Thus tradition all-objective experiments will be replaced by half-objective forecasting ones in the lab, so that the performances of rudder can be test conveniently on the ground. With development of aviation, spaceflight and national defense industry, performance index of electro-hydraulic load simulator is increasing rapidly. The development of high performance electro-hydraulic load simulator is important in theory and practice.In loading system of electro-hydraulic load simulator, active movement of rudder system can result in so-called surplus force to loading system which used to simulate rudder moment. Surplus force almost affected overall dynamic performances of electro-hydraulic load simulator system with large intensity and continuous variation derived from variable velocity of rudder system. Therefore, how to restrain or eliminate surplus force became a key technology in electro-hydraulic load simulator system.After reading numerous literatures and reference materials related at domestic and overseas, the research achievement about surplus force is summarized. Research direction and content are decided by analyzing the merit and shortcoming of related products and control methods.In this dissertation, the author builds up mathematical model of electro-hydraulic load simulator system. And it also builds up model of P-Q servo-valve and complete system based on bond graph theory, which consider the nonlinear of orifices and real-time changing characteristic of liquid capacity in the cylinder chambers. Then, explaining the characteristic of surplus force, which can provide theoretical supports for restraining surplus force. Sequently it deals with frequency characteristics of the rudder and loading systems in Matlab and simulate the system with 20-sim. When improve the loading performance with adding the structure invariance principle to eliminate surplus force. To improve loading performance of loading system controlled by P-Q servo-valve, this dissertation analyzes the uncertainties of electro-hydraulic load simulator, then designs a robust controller...