Distributed fixed-time attitude coordinated tracking for multiple rigid spacecraft via a novel integral sliding mode approach

In this paper, the distributed fixed-time attitude coordinated tracking control problem is investigated for multiple rigid spacecraft in the presence of external disturbances. A novel integral sliding mode control scheme is proposed for second order systems with external disturbances, which provides bounded convergence time independent of initial conditions. By constructing a sliding-mode estimator for each spacecraft, the requirement of the neighbours’ control input information is removed, which reduces the communication flow. A fixed-time disturbance observer is introduced to compensate external disturbances. Then, the composite attitude tracking control laws are developed to guarantee tracking errors converge to zero in fixed time. The fixed-time stability of the closed-loop system is proven by employing the Lyapunov method. Finally, the performance of the proposed control approach is illustrated by numerical simulations.