Study Of The Pneumatic Load Simulator Based On Feedback Linearization

Load-simulator is a device developed to test the performance of rudder control system in the lab by simulating and applying air moment the rudder suffering. High performance load-simulator is in urgent need for the examination of newly developed aircrafts and control techniques.A pneumatic load-simulator, constructed with a cylinder controlled by proportional valve,is established in this paper, and its characteristics and control strategy are studied. First, the A.C. servo motor mathematic model is established, through analyzing the transfer function of the disturbance, the infection of disturbance force to the rudder position controlling system is given. Then the mathematic model of the load simulator is established, the method of feedback linearization can process nonlinear object to be a pseudo linear system. This method is different from working-point linearization. To a certain system, working-point linearization can lose system information, while feedback linearization method retains all the system information completely. After feedback linearization obtaining the model, the controller based on feedback linearization model is designed. So closed loop system possessed better dynamic characteristics. Then the simulation is carried out.The control scheme of the experiment is set using real time toolbox of Maltab,the controller based on feedback linearization model is used to test the superfluous force and the effect of tracking of 0.5Hz, 1Hz, 2Hz , 4Hz and 5Hz . The final results which are match to the results of the simulation show that the performance of pneumatic load-simulator is satisfying , though the superfluous force exists , it is small. When the frequency is higher, the superfluous force is bigger, the effect of tracking is worse. When the load grads is bigger, the effect of tracking is better.