Event-triggered integral sliding mode controller for rigid spacecraft attitude tracking with angular velocity constraint

Abstract

This paper investigates the attitude trajectory tracking problem of a rigid spacecraft subject to external disturbances and full-state constraint under the event-triggered scheme. By incorporating a barrier Lyapunov function (BLF) into the dynamic surface technique, we develop a coordinate-free integral sliding mode controller which cannot only deal with the state constraint but also enforce the tracking error converge into a vicinity of the origin. To save the computation and communication resources, a modified integral sliding mode-based robust event-triggered controller is proposed, in which the control torque generation and the information transmission of attitude and control signal only need to be implemented at some discrete time when the predefined measurement error exceeds a constant threshold. Furthermore, a lower bound estimation on the inter-execution intervals is also given to show that Zeno behaviour can be avoided. Finally, numerical simulations are presented to demonstrate the effectiveness and robustness of the proposed controller.