Control Design For A Passive Torque Servo System Based On Robust Methods

A classical engineering application of the passive torque servo system(PTSS) is the aeroload simulator(ALS). It is an important half hardware-in-loop simulation equipment, which is often used to simulate the aerodynamic torque load on the missile rudder or elevon actuators in the flight. With the requirements of national defense, the performance and flight speed of missiles and aircrafts are increased rapidly, which leads to the high dynamic responsibility and high precision requirement of ALS. Also, the using of robust control method on the mechanical servo system is remained to be studied. Taking the electrical aeroload simulator as the background, this paper studied the control design of the PTSS based on the robust control method.First, based on the permanent magnet synchronous motor(PMSM), the structure of control system is provided. The influence of the rudder performance on the model was considered, and modeled it as the disturbance channel in the model. Based on the analysis of the driven motor and measured rudder, the uncertainties in the model are mainly caused by the fluctuations of the PMSM and the measuring rudders, and then the multiplicative uncertainty is adopted to describe the model.Secondly, the dynamic features of the control system is analyzed, and the surplus torque problem is started. The subsystem interaction model is given to show the forward path and the surplus torque path. Then, the control features of the system are studied.Thirdly, based on the thought of the compensation, the disturbance observer is introduced. The classical disturbance observer is designed to compensate the surplus torque and the other torque disturbance. Also, the improved disturbance observer is designed to suppress the high-frequency measurement noise. The efficient of the disturbance observer design and its independence with control design are studied via simulation.Finally, after researching the weighting function selection, two robust control methods are used to design the control system of the PTSS, respectively, the mixed sensitivity method and the ?-synthesis method. With these two methods, the robust stability and the robust performance problem are studied. Also, the comparison with the classical PID control method is displayed via the simulation.