Research Of Improving Performance Of The Electro-Hydraulic Load Simulator

The electro-hydraulic load simulator is a half simulative equipment simulating the air power torque exerted on the rudder of aircraft flying in the air,and is a typically passive force (torque) servo control system .It is used to test the performances of aircraft rudder on the ground. Thus the classical self-destructing all-objective experiment to half-objective forecasting experiment in laboratory to achieve the aims such as shortening research and manufacture time, saving developing funds, enhancing reliability and success proportion. Therefore, it is significant to national defense and military industry.In the load simulator, active movement of rudder system causes so-called surplus torque to loading system which used to simulate hinge moment. It is difficult to replicate hinge moment accurately and rapidly because surplus torque affect dynamic performances of load simulator system badly with large intensity and continuous variation derived from variable velocity of rudder system. Therefore, how to restrain and eliminate surplus torque became a key technology in electro-hydraulic load simulator system. In addition, the system inherent uncertainties also degrade the system comprehensive performances to large extent.The dissertation clarifies the main technical problem and technical estimating index, and analyzes the basic operational principle and basic structure of the load simulator. This research work builds up mathematical model of the load simulator system, explains the mechanism and characteristics of surplus torque. Through simulation the dissertation analyzes the effect of connect stiffness, load inertia, pressure- flux coefficient to the active load system and surplus force (torque). Loading grads is another non-structure coefficient influencing loading characteristics except loading frequency. The low grads characteristics are analyzed deeply by simulation, and found that applying structure invariance principle with acceleration compensation can reduce loading grads effectively. The dissertation also simulates and compares the systems with connect hole of different size, and founds that the size of connect hole has an optimized value. The opening of connect hole should choose properly.