The Control Strategy Study Of The Frame Servo System On Control Moment Gyro

Single frame control moment gyro(SGCMG)has already successfully applied to the target aircraft of "Tiangong-1" in China in 2011 and will be further applied in chinese space laboratory and space station projects in the future.In view of the SGCMG framework servo system will be subjected to various types of disturbance on the spacecraft platform,its servo control performance will be affected.This thesis focuses on the interference analysis and control strategy optimization design of SGCMG frame servo system.The main research work is as follows:Three characteristics of the gyroscope’s rigid in space,precession and anti-moment effects are briefly analyzed.Their roles in the working principle and disturbance of SGCMG are studied.Choose surface-mount permanent magnet synchronous motor(PMSM)as the motor actuator for the frame servo system reasonably.Establish the mathematical model of PMSM,and build the servo system based on space vector pulse width modulation control theory.The disturbance analysis of the control performance of the frame servo system is carried out,mainly including the low-frequency disturbance torque which the spacecraft is coupled to the frame,the high-frequency disturbance torque caused by the unbalanced vibration of the gyro rotor,the friction moment of the frame bearing,the torque fluctuation caused by the driving motor and various errors of the servo controller.The sliding mode disturbance observer was designed to observe the disturbance of low-frequency interference torque and to carry on the simulation analysis.The high frequency torque disturbance caused by unbalanced vibration of high speed rotor is modeled and analyzed.Complete frame friction analysis model.This dissertation has carried on the frame servo system control optimization strategy research.A feedforward compensation strategy is used to design a control system based on speed and acceleration feedforward compensation and friction feedforward compensation,which improves the system response frequency,tracking accuracy and anti-interference ability.In order to further strengthen the control performance,the control system is designed by using the back-stepping time-varying sliding mode control strategy.The time-varying variable and switch adaptive gain is added into the design.At the same time,the disturbance observer is used to enhance the robustness of the controller.The parameters of inertia involved in the two control strategies are identified.The effectiveness of the above strategy is analyzed in turn through simulation comparative experiments.The hardware design,software design and PC operating software of frame servo controller are completed and implemented for all kinds of error of servo controller.Based on the experimental platform of controller construction,a comparison experiment of PI control strategy and backstepping sliding mode control strategy was carried out on the platform,and the servo control performance of control strategy was analyzed.