Study Of The Pneumatic Load Simulator

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. The rudder is driven by an servo motor, and its operating mode and control parameters are setted after careful study and tuning. The 4th order mathematic model of the load simulator is established and its linear form is obtained by linearizing at operating conditions. Also the coefficients of the linear model are calculated and discussed,based on measured characteristics of the proportional valve. Grounded on that model, a piecewise PID controller with forward feedback is designed and simulated by Matlab, and the performance is better compared with PID control.The control scheme of the expenriment is setted using real time toolbox of Maltab,experiments of 0.5Hz, 1Hz, 2Hz and 5Hz triangle wave stimulation are carried out. The final results show that the performance of pneumatic load-simulator is satisfying, and the superfluous force, though there exists, is small.