An autonomous fault detection and fault-tolerant control solution combining Model Predictive Control (MPC) and Label Distributed Learning (LDL) is developed for the position tracking and attitude synchronization problems in autonomous satellite rendezvous and docking. The proposed algorithm can deal with center of mass (CM) variations and time-varying mass characteristics due to satellite fuel consumption, actuator saturation and fault, and external disturbances. Firstly, a six-degree-of-freedom (6-DOF) satellite translation-rotation coupling model was established to express the relative motion between the satellite and the target, taking the above factors into account. Subsequently, an on-board autonomous closed-loop fault-tolerant control algorithm using MPC is proposed, in which an LDL-based fault detection mechanism is embedded. The scheme specifies that propulsion faults are estimated by calculating the difference between the MPC's prediction of the satellite's future state and the measured change in the actual state. And the mapping matrix between the commanded force/torque and the actual force of the propulsion system is updated in real time to achieve autonomous fault detection and compensation on board the satellite. Among them, the LDL-based fault detection scheme is trained offline. It requires only simple matrix operations for on-orbit use, which is low-cost and suitable for resource-limited space environments. The additional creation of a time-varying disturbance observer allows the estimation and compensation of unmodelled errors and external disturbances. The stability of the proposed fault-tolerant control algorithm is rigorously demonstrated using Lyapunov analysis. Finally, numerical simulations show that the proposed method can successfully achieve autonomous satellite docking under different combinations of thruster faults.

中文翻译：

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具有质量特性和执行器不确定性的卫星自主交会容错控制

针对自主卫星交会对接中的位置跟踪和姿态同步问题，开发了一种结合模型预测控制（MPC）和标签分布式学习（LDL）的自主故障检测和容错控制解决方案。该算法可以处理由于卫星燃料消耗、执行器饱和和故障以及外部干扰引起的质心（CM）变化和时变质量特性。首先，考虑上述因素，建立六自由度（6-DOF）卫星平移-旋转耦合模型来表达卫星与目标之间的相对运动。随后，提出了一种使用MPC的车载自主闭环容错控制算法，其中嵌入了基于LDL的故障检测机制。该方案规定，通过计算 MPC 对卫星未来状态的预测与测量到的实际状态变化之间的差异来估计推进故障。实时更新推进系统指令力/扭矩与实际力之间的映射矩阵，实现星上自主故障检测和补偿。其中，基于LDL的故障检测方案是离线训练的。在轨使用仅需简单的矩阵运算，成本低廉，适合资源有限的太空环境。额外创建时变干扰观测器可以估计和补偿未建模的误差和外部干扰。使用 Lyapunov 分析严格证明了所提出的容错控制算法的稳定性。最后，数值模拟表明，该方法能够成功实现不同推进器故障组合下的自主卫星对接。