Controle de atitude por atuação magnética de um satélite da classe cubesat 3u

Abstract

This work presents an approach for a PID-based control design for LTI-MIMO systems applied to a magnetically actuated LEO 3U Cubesat model. Firstly, the mathematical model of a nadir-pointing magnetically actuated satellite is derived. The magnetic underactuation problem is discussed as it is shown that the principle of magnetic dipole moment from magnetorquers interacting with the geomagnetic eld allows only manoeuvres which the mechanical torque exists perpendicularly to the local magnetic eld direction. As a drawback, it is also shown that the interaction with the geomagnetic eld inserts non-linearity and uncertainty parameter issues into the system model. In order to address this problem, a magnetic LTI model is obtained from a periodic approximation of the geomagnetic eld model. As for the controller design, LQ and H∞ with output feedback techniques are formulated for the PID-based control design. For validation, numerical simulations including the non-linear model of the satellite, e ects of the gravity gradient disturbance, and a realistic geomagnetic eld model were performed. As a result, a robust PD controller succeeded for all simulated cases. Therefore, this work concludes with a conceptual attitude control proposal that matches with the SERPENS-II Space Mission.