Fixed-time attitude tracking control for spacecraft based on adding power integrator technique

In this article, the fixed-time attitude tracking problem for rigid spacecraft is investigated based on the adding-a-power-integrator control technique. First, a fixed-time attitude tracking controller is designed to guarantee fixed-time convergence of tracking errors. Then, by considering the presence of random disturbance and actuator faults, an adaptive fault-tolerant attitude tracking controller is designed to guarantee tracking errors converge to a residual set of zero in a fixed time. The complete bounds on settling time are derived independently of initial conditions. The simulation results illustrate the highly precise and robust attitude control performance obtained by using the proposed controllers.