This paper addresses the distributed predefined-time attitude consensus problem for multiple uncertain spacecraft systems in the presence of model uncertainties and external disturbances. Firstly, a new predefined-time terminal sliding surface (PTS) is proposed. Secondly, a distributed predefined-time consensus control (DPTC) based on the PTS is designed to solve the robust attitude consensus problem. It is proved that the proposed DPTC can ensure that the attitude consensus errors converge to an arbitrary small bound centered on equilibrium point within predefined time and then go to equilibrium point asymptotically. The appealing features of the proposed control are faster convergence, higher precision, stronger robustness and easy implementation. Simulations verify the effectiveness of the proposed approach.INDEX TERMS Distributed control, Predefined-time, attitude consensus tracking, multiple spacecraft, formation flying.

This article addresses the predefined-time guaranteed performance attitude tracking problem for takeover the non-cooperative target spacecraft with model uncertainties, adversarial control torque and gravity gradient torque. Firstly, a novel prescribed performance function (NPPF) is exploited, and then a new non-singular predefined-time terminal sliding mode (NPTSM) surface with the transformed tracking error is constructed. Secondly, a non-singular predefined-time prescribed performance control (NPTPC) is designed to achieve the guaranteed performance within predefined-time. It is proved that the proposed control can ensure that the attitude tracking error satisfies the prescribed performance boundaries all the time and converges to a preset small region centered around the equilibrium point within predefined time and then tends to the equilibrium point asymptotically. The appealing feature of the proposed control is predefined-time stability with quantified transient performance and steady-state accuracy. Simulations verify the effectiveness and improved performance of the proposed approach.