Finite-time convergent control for spacecraft attitude stabilization based on the adding power integrator technique

This article investigates the control of attitude stabilization for a rigid spacecraft using non-singular terminal sliding mode control (NTSMC). A new problem with the traditional NTSMC has been pointed out. This issue is that the mathematical expression of the upper bound of convergence time will approach infinity as the angular velocity approaches zero. In order to address this issue in the traditional NTSMC, a new control method is proposed. This method utilizes the technique of "adding a power integrator" (AAPI), and provides a bounded expression for convergence time. When considering external disturbances, control input limitations, and actuator faults, the attitude and angular velocity can eventually stabilize to a residual set of equilibrium within a finite time. The simulation results demonstrate that the proposed controllers achieve highly accurate and resilient attitude control performance.