Abstract:

 An attitude slew maneuver control based on the logarithmic convex potential function is proposed for a microsatellite with multiple attitude and angular velocity constraints. Since the mission requirements, the optical instruments equipped on the microsatellites are required to point their boresight without direct exposure to the bright objects while the high-gain antenna must point to the ground for maintaining the communications. In this paper, the logarithmic convex potential function is introduced to solve the attitude path planning issue and the angular velocity constraint problem is also well tackled by the fixed barrier Lyapunov function. Compared with the on-line optimization method, the proposed method can reduce the computation burden and it is very fit for a microsatellite with low computation ability. In addition, the disturbance moments are taken into account and the nonlinear adaptive disturbance observer is inserted into the control law in order to enhance the robust capability. Finally, the simulations demonstrate that the pointing constraints are properly avoided and the desired attitudes are obtained by the proposed control method without violating the angular velocity constraints.

Key words: Microsatellite, Attitude control, Pointing constraints, Angular rate constraints, Disturbance observer