SIMULATOR STUDY OF A SATELLITE ATTITUDE CONTROL SYSTEM USING INERTIA WHEELS AND A MAGNET

SUMMARY Three-degree-o~-~reedom tests o~ an automatic attitude control system ~or a satellite have been made by using an inertia simulator mounted on an air bearing. The control torques used in the system were the inertia reaction torque of three body-mounted flywheels and the magnetic reaction torque o~ a permanent bar magnet. The control signals used ~or the wheel were an attitude input provided by light sensors and the wheel-angular-velocity input provided by the tachometer. The mag­net was used for removing momentum ~rom the system and was controlled by the wheel angular velocity. Tests were made to demonstrate the stability of the system, the sensitivity that could be obtained with the system, and the operation of the mag­net system. The results show that attitude control that would be satisfactory for many missions can be achieved with this control system. INTROOOCTION The use o~ inertia reaction wheels for satellite attitude control has been suggested in many studies of long-time missions where the weight