Investigation on magnetic-based attitude de-tumbling algorithm

Abstract

Most of the low-cost NanoSats, which run on the low-earth orbits and have no severe pointing requirement, usually adopt magnetic-based attitude control scheme as an important or even the dominant attitude control strategy to de-tumble and stabilize themselves. The attitude control components regularly equipped include magnetic torquers and magnetometer, and sometimes even a miniaturized momentum wheel. The primary task of the attitude control system of the NanoSats is to achieve rate damping and the famous B-dot control algorithm is widely adopted to de-tumble the satellites. However, when the initial angular velocity is significantly fast and an obvious lag exists in the control system, the wide-spread B-dot control algorithm would fail to de-tumble the satellite. Oppositely, the angular velocity would be controlled to a large-scale one. In this paper, one novel rate damping algorithm is proposed to deal with this case. For momentum satellites, during de-tumbling control process based on B-dot algorithm, their attitude motion is analyzed in detail. Analysis indicates that the roll-yaw control channel is stable and the pitch angle tumbles from 180 deg down to −180 deg in about one orbit period. In addition, the optional range of the bias moment has been specified. Simulation results indicate that the proposed novel damping algorithm is effective and the momentum satellite's attitude motion during B-dot damping process is coincided with the resulted attitude motion characteristics, which is benefit for the satellites, which are running in dawn-dusk orbits, to obtain solar energy for the positive/negative Y-body axis is always pointing at the negative normal direction of the orbital plane.