Nonsmooth attitude stabilization of a flexible spacecraft

A flexible spacecraft is a kind of complex systems consisting of rigid bodies and flexible appendages. The attitude maneuvering or external disturbances will unavoidably lead to a continuous vibration of flexible appendages. It is known that the finite-time control technique offers better convergence and disturbance rejection properties. To achieve the high-accuracy attitude stabilization, a nonsmooth attitude-stabilizing control strategy based on the finite-time control technique is investigated for flexible spacecrafts in this paper. The rigorous mathematical stability analysis of the overall closed-loop system is made by means of cascaded systems theory. The novelty of the paper is that the relation between the convergence region of states and the control parameters can be obtained, which indicates that the steady-state error can be preestimated when the control parameters are determined. Simulation results show that not only can the attitude be stabilized precisely, but the elastic vibration of flexible appendages can be suppressed effectively as well.