Fixed-time control for spacecraft attitude tracking based on quaternion

In this paper, the attitude tracking control problem is investigated for a rigid spacecraft. Robust finite time controllers based on the quaternion and Lagrange-like model are proposed to solve this problem with model uncertainties and external perturbations. The controllers guarantee the convergence of attitude tracking errors in fixed time, where the settling time can be set in advance, and this merit is different from all the existing controllers for spacecraft attitude tracking problem. The controllers are derived using the Lyapunov theory, so the stability of the closed-loop system is guaranteed. Moreover, the modified controllers are provided to alleviate the chattering phenomenon and eliminate the singular problem. Finally, simulation results are given to demonstrate the efficiency of the proposed methods. (C) 2015 IAA. Published by Elsevier Ltd. All rights reserved.