Nonsingular fixed-time attitude coordinated tracking control for multiple rigid spacecraft

• Published in: ISA transactions Vol. 129; no. Pt B; pp. 243 - 256
• Main Authors: Tian, Ye, Du, Changkun, Lu, Pingli, Jiang, Qing, Liu, Haikuo
• Format: Journal Article
• Language: English
• Published: United States Elsevier Ltd 01.10.2022
• Subjects: Attitude coordinated control; Distributed observer; Fixed-time control; Nonsingular sliding mode; Sliding mode control(SMC); Spacecraft formation flying(SFF); Distributed observer; Nonsingular sliding mode; Spacecraft formation flying(SFF); Fixed-time control; Sliding mode control(SMC); Attitude coordinated control
• ISSN: 0019-0578; 1879-2022; 1879-2022
• DOI: 10.1016/j.isatra.2022.02.024

This paper investigates the problem of fixed-time attitude coordinated control for multi-spacecraft systems with unknown external disturbance. Firstly, a distributed fixed-time observer is introduced to estimate the states of the virtual leader. The observer can track the leader completely in a fixed time without dependence on the initial conditions of the leader and observer. Then, we propose a novel nonsingular fixed-time sliding mode tracking controller to address the fixed-time attitude tracking problem. It is noteworthy that the requirement on initial conditions of spacecraft is removed in the proposed nonsingular sliding mode controller. Due to the robustness of sliding mode control, the influence of external disturbance can be eliminated, such that each spacecraft can track desired attitude trajectories precisely in a fixed time. Hence, the fixed-time attitude coordination for multiple spacecraft can be achieved. Finally, numerical simulation results and comparisons reveal the effectiveness of the proposed algorithms. •Firstly, a novel nonsingular fixed-time sliding mode controller is proposed to solve the singularity problem of terminal sliding mode (TSM). We adopt a novel area division method to avoid the singularity of fixed-time TSM and obtain a more precise estimation of convergence time.•Secondly, compared with existing finite-time attitude cooperative control methods, the fixed-time control scheme adopted in this paper has more advantages. The upper bound of convergence time is independent on the initial states and can be adjusted by controller parameters.•Thirdly, a novel distributed fixed-time observer is proposed, which can be also used to general linear systems fixed-time consensus design. Utilizing the proposed observer, we can obtain a precise estimation of the leader states in a fixed-time.•In conclusion, there are few results of fixed-time attitude coordinated control and still exist some deficiencies in foregoing works. More challenges are posed in the fixed-time attitude control for multiple spacecraft.