Constrained Nonsingular Terminal Sliding Mode Attitude Control for Spacecraft: A Funnel Control Approach

This paper presents an adaptive constrained attitude control for uncertain spacecraft. Inspired by the concept of nonsingular terminal sliding mode and funnel nonlinear systems, a novel is introduced which contains time-varying gain to handle constraints imposed on spacecraft attitude. Indeed, when trajectory approaches boundary constraint set, effort as well will increase in order preclude from intersecting boundary. Then, it analytically proved that system trajectories converge arbitrary small region around origin within fixed time where smallest upper bound convergence determined independent parameter controller. Further, proposed scheme without having use any piecewise continuous function simplifies stability analysis. These properties distinguish existing finite/fixed-time controls. Finally, several simulation results confirm robustness performance framework.