Study On Controller Design Of Electric Torque Load Simulator Servo System Based On Internal Model Control

Electric torque load simulator (ETLS) is an essential equipment of the hardware-in-loop simulation system, which is often used to simulate the aerodynamic torque load on the rudder of aerocraft in the process of flight. ETLS is a typical passive torque servo system. The surplus torque, which is generated from rudder's active movement, is a troublesome obstacle of ETLS servo system. This thesis takes certain ETLS as background. After the characteristics of ETLS have been researched thoroughly, internal model control (IMC) theory is applied to design ETLS servo system.Firstly, the development of aerodynamic load simulator is introduced, and the surplus torque rejection methods which are in use are analyzed, whose advantages and disadvantages are indicated. Then the general theory of IMC is introduced, so is the status of application of IMC.Secondly, the mathematical model of the ETLS servo system including rudder system is built using the physical modeling method, and the uncertainty of the system is analyzed. It can be concluded that the influence of the uncertainty came from the different characteristics between different rudder systems is the most important one, and this uncertainty can be described by multiplicative uncertainty.Thirdly, the model of ETLS servo system is simplified to the couple model between the rudder and the ETLS. Based on the simplified model, comparison of the features of the forward channel with and without considering the rudder's characteristics is made, so are the features of the surplus torque. From that, it can be concluded that the impact of rudder is equivalent to decrease of the torsion stiffness of the ETLS system. Surplus torque problem is studied specially, and it also can be concluded that surplus torque of ETLS servo system is directly related to the rudder features, and has specialties of direct effect on output port, intense coupling, only impact on system dynamic performance, action'ahead'.Finally, aiming at the main control problem of ETLS servo system, applying IMC theory, this servo system is designed by using IMC structure with feedback filter. To design a feedback filter, a method based on robust controller design theory is given. Simulation results show that designed controllers can commendably ensure the system robust stability, the performance of surplus torque rejection and torque tracking, so the validity and feasibility of presented controller design method are proved.