On event-triggered nonsmooth attitude tracking controller for a rigid spacecraft

This article focuses on the problem of finite-time attitude tracking control for a rigid spacecraft with event-triggered inputs. The existing event-based attitude control methods are developed from the smooth control law and can only provide at best Lipschitzian exponentially convergent. Because the nonsmooth control law shows a faster convergent rate and better control performance, a new event-triggered nonsmooth attitude tracking controller is proposed through the emulation method of a continuous-time finite-time attitude controller. With the aid of Lyapunov theory and finite-time stability lemma, the stability analysis of the closed-loop system is given and the event-triggered control system is Zeno-free. Like the case of a continuous-time nonsmooth attitude controller, it is proved that the event-triggered nonsmooth attitude controller maintains a better disturbance rejection ability. Finally, some simulation results are given to verify the theoretical results.