Improved nonsingular terminal sliding mode attitude tracking control for reentry vehicle

This paper investigates the attitude tracking control problem of reentry vehicle with modeling inaccuracies and external disturbances. An improved nonsingular terminal sliding mode control method is presented, and a faster convergence rate is obtained in comparison with the conventional nonsingular terminal sliding mode control (NTSM). By the proposed control strategy, the possible singularity during the control phase is avoided, and robustness is also guaranteed. Simulation is made for a reentry vehicle in the condition aerodynamic parameters and atmospheric density are perturbed. The results show the effectiveness of the proposed strategies.