Automatic control of the satellites' attitude and stored energy using inertial wheels

The paper presents the design of a new automatic system for the control of the satellites' attitude and stored energy by using four inertial wheels as actuators. The design of the system's control law is based on the usage of a Lyapunov function depending on the quaternion error vector and on the orientation angular rate error of the satellite tied frame with respect to a reference frame. The control law of the inertial wheels is obtained from the stability condition of the closed loop system. During the satellite's tracking stage, the control is achieved by means of the inertial wheels; the initialization of the satellite tied frame is made by means of the satellite's thrusters. The software implementation and validation of the new control architecture is achieved by using the Matlab/Simulink environment.