Hasan Muhammad Noman, Chen Yong, Liang Jiongjiong, Wen An
Yangtze Delta Region Institute of University of Electronic Science and Technology (UESTC), Huzhou, Zhejiang, 313001, China.
Yangtze Delta Region Institute of University of Electronic Science and Technology (UESTC), Huzhou, Zhejiang, 313001, China; School of Automation Engineering, University of Electronic Science and Technology of China, Chengdu 611731, China.
ISA Trans. 2024 Mar;146:87-98. doi: 10.1016/j.isatra.2023.12.022. Epub 2023 Dec 18.
This paper deals with the appealing problem of fixed-time fault-tolerant attitude control, using attitude-information-only, for a flexible spacecraft under the influence of inertial parametric variations, external disturbances, and multiple actuator faults while suppressing the flexible appendages' vibrations without using additional sensors or smart vibration suppression actuators. First, an adaptive fixed-time model-free observer (AFTMFO) is designed, using the attitude information, for rapid estimation of unavailable angular velocity. A novel adaptive continuous control is then synthesized based on an anti-unwinding fast fixed-time nonsingular sliding surface (AFFTNSS), utilizing variable gains in both the control law and sliding surface; that simultaneously alleviates the chattering but also improves the convergence speed when compared to existing fixed-time approaches. The proposed scheme offers superior performance characteristics such as velocity sensor-free fixed-time attitude maneuvering with high pointing accuracy, fault tolerance, vibration suppression, nonsingular and chattering-free control. The spacecraft can carry out the coveted control objective in a predeterminable time independent of the knowledge of initial states while overcoming the unwinding effect to reduce the control effort and time. The fixed-time closed-loop stability of the proposed scheme is corroborated via Lyapunov techniques. Finally, a comparative simulation analysis with the existing results elucidated the proposed scheme's efficacy.
本文研究了在惯性参数变化、外部干扰和多个执行器故障影响下的挠性航天器仅利用姿态信息进行固定时间容错姿态控制这一引人关注的问题，同时在不使用额外传感器或智能振动抑制执行器的情况下抑制挠性附件的振动。首先，利用姿态信息设计了一种自适应固定时间无模型观测器（AFTMFO），用于快速估计不可用的角速度。然后基于一种抗解缠快速固定时间非奇异滑模面（AFFTNSS）合成了一种新型自适应连续控制，该滑模面在控制律和滑模面中均采用可变增益；与现有固定时间方法相比，这不仅减轻了抖振，还提高了收敛速度。所提出的方案具有卓越的性能特性，如无速度传感器的固定时间姿态机动、高精度指向、容错、振动抑制、非奇异且无抖振控制。航天器能够在与初始状态知识无关的预定时间内实现期望的控制目标，同时克服解缠效应以减少控制努力和时间。通过李雅普诺夫技术验证了所提方案的固定时间闭环稳定性。最后，与现有结果的对比仿真分析阐明了所提方案的有效性。
