On novel appointed-time inertia-free adaptive attitude control of spacecraft

This paper investigates a novel fixed-time attitude control scheme for a rigid spacecraft with unknown inertial properties and external disturbance. First, a new prescribed performance function is developed, based on which an adaptive inertia-free controller is constructed to guarantee the fixed-time convergence. Compared with the existing finite-time/fixed-time attitude controllers based on sliding mode control technique, the primary advantage is the fractional power state or output feedback is not used, while the arbitrarily appointed-time convergence and steady-state tracking accuracy can be simultaneously guaranteed. Finally, a group of illustrative examples are employed to validate the effectiveness of the proposed control scheme.