Research On Control Method Of Electric Load Simulator

The load simulator can simulate various kinds of moment the rudder of the aircraft suffered during the flight under the laboratory environment,and it is an important ground simulation equipment to test and analyze the performance of the rudder.In order to ensure the accuracy of the measurement, the load simulator should meet the requirements of high loading precision, fast response, strong anti-interference ability and so on.However, under the laboratory environment, surplus torque caused by mechanical connection between the rudder and the load simulator and objective various nonlinear factors will affects dynamic response and tracking accuracy of the system.Therefore, how to suppress the surplus torque and to increase the dynamic performance of the system on this basis are the focus in the study of load simulator.In order to improve the precision and the dynamic performance of electric load simulator,the mathematical model of the system is established based on the working principle of the system.And the error sources of loading system and the influence of the inertia,stiffness, friction and gap on the accuracy of the load simulator are analyzed in depth.The corresponding control methods are proposed for different types of loading errors as well.For the loading error caused by the dynamic performance of the system, using lead emendation and differential toward PID to improve the stability and tracking accuracy of the system;For the disturbance of surplus torque,the displacement of rudder, angular velocity of load simulator and the current of rudder are used as the interference signal, and the feed-forward compensation based on structure invariance principle is used to suppress the interference. For the influence of nonlinear factors such as friction and gap on the accuracy of the system,the PID controller based on wavelet neural network and the gap inverse model are used to compensate the system precision.Finally, combining with load simulator performance indicators, the load simulator in different working conditions has been simulated and analyzed. The simulation results showthat the static and dynamic characteristics of the system are improved and the surplus torque is restrained well after adding the control algorithm.Meanwhile,the compensation effect to the friction and nonlinear gap has been also simulated and analyzed. The results verified the validity of the control algorithm proposed in the paper.