针对存在执行器故障、转动惯量偏差以及外部扰动等系统不确定性的航天器姿态跟踪问题,提出一种有限时间自适应容错姿态控制方法.建立基于四元数的航天器姿态动力学模型、执行器故障模型和系统不确定性模型,并将执行器故障分为乘性故障和加性故障两大类;利用滑模控制和有限时间控制理论设计有限时间姿态控制器,并通过设计自适应变量及更新方法对执行器故障以及系统不确定性引起的控制偏差上界进行估计和补偿,使姿态控制器对故障和扰动具有良好的适应性和鲁棒性.得到的新型有限时间自适应容错姿态控制器能够保证航天器在执行器故障以及系统不确定性条件下在有限时间内精确收敛到期望值.利用 Lyapunov 稳定性理论证明了系统的渐进稳定性和有限时间稳定性,数值仿真验证了所提出方法的可行性和有效性.%A novel finite-time adaptive fault-tolerant control method is proposed for the spacecraft attitude tracking subject to system uncertainties, such as unknown inertial uncertainty, actuator fault and saturation, external disturbances, etc. The spacecraft dynamics and system uncertainty models are established, which divide the actuator fault into two types: a gain fault and a deviation fault. A finite-time attitude controller is designed based on sliding mode theory and finite-time stability theory. A new system adaptive parameter and its update law are designed to estimate the upper bound of the control error caused by actuator fault and system uncertainty. The novel finite-time adaptive fault-tolerant attitude controller can ensure the system precisely converge to the expected value in finite time in spite of the actuator fault and system uncertainty. The asymptotical stability and finite-time stability of the system under the proposed control method are proved using Lyapunov stability theory. Numerical simulations demonstrate the feasibility and effectiveness of the proposed control algorithm.
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