Fault-tolerant control of flexible satellite with infinite-dimensional model

Abstract

Fault-tolerant control (FTC) strategy based on adaptive integral sliding mode (AISM) is proposed to stabilize a flexible satellite, subject to inertia uncertainties, external disturbances, and actuator faults. Using Hamilton's principle, the satellite dynamics is presented as a coupled Ordinary Differential Equation (ODE) and Partial Differential Equation (PDE). The control scheme is based on the infinite-dimensional model of the flexible satellite with no discretization, so the spillover instability phenomenon is eliminated. This is the most important advantage of the proposed control scheme over the previous FTC schemes that have been used for the flexible satellite. Stabilization and vibration suppression are performed using control torque that is applied to the rigid center, and there is no need to implement in-domain actuators on panels to stabilize their vibration. First, a novel nominal controller based on the infinite-dimensional model of the satellite is designed for a healthy system. Then, an integral sliding surface, including angular velocities, internal reaction torques, and nominal control, is proposed. Finally, an AISM controller with an adaptive estimator is designed to accommodate actuator faults and other uncertainties. System stability is guaranteed for small changes in a neighborhood around the sliding surface with simultaneous vibration damping. Numerical simulations illustrate the effectiveness of the proposed control strategy.