This article investigates the problem of distributed attitude tracking control for the leader‐follower spacecraft in the presence of the external disturbances, model uncertainties, and actuator faults. First, a novel fixed‐time observer is developed to estimate the angular velocity of the leader. In contrast to the existing finite‐time observer design methods, the settling time is independent of the initial conditions, and the upper bound of the angular acceleration of the leader is not required for each follower. To estimate and compensate the total uncertainties with finite‐time convergence, a fraction‐based adaptive scheme is designed. Based on the fixed‐time observer and the adaptive scheme, a continuous finite‐time distributed control law is developed such that the stability of the observer‐controller closed‐loop system is guaranteed. Numerical simulations are illustrated to demonstrate the performance of the control scheme.

中文翻译：

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带固定时间观察者的跟随跟随者航天器的有限时间协作姿态控制

本文研究存在外部干扰，模型不确定性和执行器故障的情况下，跟随跟随航天器的分布式姿态跟踪控制问题。首先，开发了一种新颖的固定时间观察器来估计引导器的角速度。与现有的有限时间观测器设计方法相比，稳定时间与初始条件无关，并且每个跟随者都不需要引导者角加速度的上限。为了用有限时间收敛估计和补偿总不确定性，设计了一种基于分数的自适应方案。基于固定时间观测器和自适应方案，建立了连续的有限时间分布式控制律，从而保证了观测器-控制器闭环系统的稳定性。