Adaptive dynamic programming-based fault-tolerant attitude control for flexible spacecraft with limited wireless resources

This paper investigates the attitude control for flexible spacecraft subject to actuator faults and limited onboard communication resources. The control torque quantization scheme is considered between the controller and actuator to reduce the communication burden on the spacecraft. An integral sliding mode control method is designed to stabilize the closed-loop attitude control system and ensure the near-optimal performance of the sliding motion. First, an iterative learning observer scheme is employed to reconstruct the actuator faults and the unknown nonlinear flexible dynamics. Second, an integral sliding surface is combined with the backstepping control method to resolve the time-varying characterization of the closed system. Third, a combination of the adaptive dynamic programming technique and the adaptive single critic neural network approximation is employed to examine the optimal control policy. Finally, the efficacy of the proposed spacecraft attitude control method is demonstrated via a simulation.