Active fractional-order sliding mode control of flexible spacecraft under actuators saturation

In this article, a novel multi-objective modified fractional-order nonsingular terminal sliding mode (MFONTSM) controller is designed for the flexible spacecraft attitude control and passive vibration suppression, assuming torque saturation in system dynamics. Then, by considering effects of components on appendages modal equation as an external disturbance, active FONTSM separately to suppress any residual vibrations using piezoelectric actuators. The practical fixed-time stability closed-loop analyzed proved Lyapunov theorem. Finally, proposed controllers’ performance has been tested presence uncertainties, disturbances, absence damping matrix study method’s effectiveness. It was observed that strategies were able achieve fast stabilization while providing substantial suppression under uncertainty disturbance even terms system.