H∞ controller design and simulation for electric load simulator based on mixed sensitivity method

According to the operating principle of the electric load simulator, the mathematic model of its actuating mechanism is built. Then, the joint stiffness between the electric load simulator and the rudder is analyzed which can impact the system performance. Based on the analysis result, the low joint stiffness should be chose under the condition of satisfying capability requirement of the system closed loop responding. Next, combining with the load gradient, the H-infinity controller based on the mixed sensitivity method is designed and synthesized by selecting the appropriate joint stiffness and weight functions. Last, the simulation and experiment results show that the controller can not only make the steady-state error of the closed loop system less than 0.5%, but also make the error of amplitude less than 10% and the lag of phase less than 10 degree when the system is stimulated by 10 Hz sine signal.