Second-order time-varying sliding mode control for reentry vehicle

Purpose-The purpose of this paper is to design a global robust and continuous control scheme for the attitude tracking control problem of the reentry vehicle with parameter uncertainties and disturbances.Design/methodology/approach-First,feedback linearization is applied to the model of reentry vehicle,resulting in three independent uncertain subsystems.Then a new second-order time-varying sliding function is proposed,based on which a continuous second-order time-varying sliding mode control(SOTVSMC)law is proposed for each subsystem.The global robustness and convergence performance of the closed-loop reentry vehicle control system under the proposed control law are proved.Findings-Simulation is made for a reentry vehicle through the assumption that there is external disturbance to aerodynamic moment and the aerodynamic parameters as well as the atmospheric density are perturbed.The results verify the validity and robustness of the proposed strategy.Originality/value-The SOTVSMC attitude controller based on feedback linearization is proposed for the reentry vehicle.The advantages of the proposed SOTVSMC are twofold.First,the global second order sliding mode is established,which implies that the closed-loop system is global robust against matched parameter uncertainties and disturbances in reentry.Second,the chattering problem is significantly alleviated.