Magnetic Control System On Small Satellite Design Simulation

Theattitudecontrolofsmallsatellite onthe safety-holdmode guaranteesthesmall satelliteto work well when instrument failures occur. Thus, high reliability is required to the attitudecontroller onthe safety-hold mode. The magnetometer and the magnetorquer are two magneticapparatuswithhighreliability,lowcostandlightweight.Also,usingmagnetictorqueinattitudecontrolhas theadvantage of low propellant consumption, and won't contaminateother devices.This thesis studies the control system utilizing magnetic torque in safety-hold mode forthree-axisstabilizedsmallsatellite.Firstly, attitude determination only using the three-axis magnetometer as the attitudemeasure device is discussed. The dynamic and kinematic equations of attitude motion of smallsatellite are presented. The measurement model of the magnetometer is deduced. An extendedkalman filter is designed to determinate the attitude. Simulation results and basic analysis arepresented.Secondly, attitude controller is designed. The models of the sun senor and themagnetorquer are introduced. Controllers in velocity damping mode and sun-orient capturingmode are designed, and analysis of the simulation results is presented. Two controllers, theMinus-Dot-B controller and the PID controller, are compared in velocity damping mode. Theresults indicate that the PID controller has higher control accuracy and shorter recursive time.Therefore, thePIDcontrollerischosenastheattitudecontroller.Finally, the designed active magnetic control system is verified by using numericalsimulations. The result shows that the designed system canmeet the technology demand of thesafety-holdmode.