Application Of The Gyrowheeel Based Attitude Control System For The Small Satellite

Dynamically Tuned Gyroscope(DTG)，which is a high-precision but low costgyro with simple mechanical structure, has been widely used in the field of navigationand guidance since1960s. If the rotor size is increased a thousand-fold, by steering thetilt and varying the spin rate of the rotor, the DTG can be used as a variable speeddouble gimbal control moment gyro,making it a new attitude control and sensitivedevice—GyroWheel.The main purpose of this thesis is to study how to apply the GyroWheel to thesmall satellites well. To study the dynamics of the GyroWheel, the space mission itsuitable for and the performance it can achieve is the main content of this paper.To study the special working state of GyroWheel, a new model is built for theGyroWheel, all four characteristic modes are detected,and explain the reason why themodes of beat frequency and twice the spin frequency disappear in the dynamics ofthe DTG. According to this, the paper concludes that increasing the tilt will bothincrease the equivalent stiffness and the periodic term proportion of the GyroWheel.Then control law is designed by means of the single-complex-input,single-complex-output transfer function, with witch the2nd harmonic torque items iseffectively suppressed.The paper analyzes the requirement of the small satellite’s space mission to theattitude control system performance, then the feasibility of the application of theGyroWheel to the LEO observation satellite is proved. Then the whole satellite attitudecontrol system model is built. The model includes the spacecraft mass properties model,dynamics mode, environmental disturbance model, attitude control law and steering law.At last, combining the satellite attitude control system model and the new model ofGyroWheel, the mechanical parameters and controller parameters are designed bysimulation, to ensure the control accuracy, and prove that the GyroWheel can achievethe accuracy requirements.To test the manufacturing accuracy of the GyroWheel, the paper explores andanalyzes the error calibration method. Firstly, the simplified expression for case angularvelocity is derived. And then describes the method to get calibration equation bymeans of the multi-position method, providing theory basis for the future calibrationwork.