Constrained Attitude Maneuver Control Based on Command Filter and Backstepping Method

Aiming at solving the problem of attitude maneuver control of spacecraft with pointing constraints, this paper proposes an algorithm based on navigation function, command filter and back stepping method. The expected angular velocity of spacecraft is obtained through navigation function, then its amplitude is saturated by a saturation function. After that, the angular velocity is used as the input of reference system. Due to the limitation of amplitude, the angular velocity command maybe non-differentiable at some point, so a first-order filter is adopted to smooth the angular velocity command. Moreover, two auxiliary systems are designed, the inputs of which are the difference between the angular velocity command before and after filter, and the difference between control input before and after saturation element respectively. The back stepping control is used to ensure the stability of attitude system and auxiliary system, therefore the attitude of spacecraft is able to track the angular velocity and attitude of reference system, which also makes the safe arrival of spacecraft's target attitude possible. Finally a simulation of this algorithm is carried out, and the results of which are thoroughly analyzed.