关键词: 欠驱动航天器, 执行机构故障, 姿态跟踪控制, 自适应混合动态规划, 容错控制, 自适应故障观测器

Abstract: Aiming at the attitude tracking control of underactuated spacecraft subject to actuator faults, with concurrent objectives of tracking accuracy and control energy consumption, this paper proposes an optimal fault tolerant control scheme based on adaptive hybrid dynamic programming (AHDP). First, under fault free conditions the control design is cast as an opti-mal control problem, and AHDP is employed to derive an approximate optimal control law that balances energy expendi-ture against tracking performance. To enable fault tolerance, an online compensation framework is developed using adaptive fault observers to separately estimate multiplicative and additive fault parameters; these estimates are then in-corporated into a compensation control law so that the faulty actuator output closely approximates nominal behavior. A Lyapunov based stability analysis proves closed loop robustness of the tracking error in the presence of actuator faults. Comparative simulations demonstrate that, compared with conventional fault tolerant methods, the proposed AHDP based controller achieves improved attitude tracking accuracy and higher fault estimation fidelity.

Key words: underactuated spacecraft, actuator faults, attitude tracking control, adaptive hybrid dynamic programming (AHDP), fault tolerant control, adaptive fault observer