Stable Supervisory-Adaptive Controller for Spinning Satellite using Only Magnetorquers

In this paper, an adaptive controller for spinning satellites has been designed to achieve high attitude accuracy. In the cases which magnetorquers are used as actuators, the generated torque is perpendicular to the Earth´s magnetic field, so a satellite is not completely controllable. In addition, the maximum value of achievable torque is limited due to capacity of magnetorquers. Hence, implementation of adaptive control law causes attitude error in system and also decreases the speed of response. To overcome these problems, a supervisory-adaptive controller has been designed. In this regard, sliding control has been used as a supervisory controller to correct the control signal applicable to magnetorquers. As a result of this method, stability of the system has been proved, output error has been decreased, and speed of response has been increased.