Observer-based finite-time sliding mode control for reentry vehicle

Purpose–The purpose of this paper is to design a disturbance observer-based finite-time global sliding mode control scheme for the attitude tracking control problem of the reentry vehicle with parameter uncertainties and disturbances.Design/methodology/approach–Feedback linearization is first introduced to transform vehicle model into three independent second order uncertain subsystems.Then a finite-time controller(FTC)is proposed for the nominal system on the basis of the homogeneity theory.Thereafter the integral sliding mode method is introduced for the vehicle with disturbances.The finite time convergence is achieved and global robustness is also assured by the combination of finite time control method and integral sliding mode strategy.Furthermore,to improve the attitude angle tracking accuracy a novel finite time disturbance observer(DO)is constructed.Findings–Simulation is made for the reentry vehicle with disturbances involved.And the results show the finite-time convergence,tracking accuracy and robustness of the proposed strategy.Originality/value–The proposed control strategy has three advantages.First of all it can achieve finite time convergence and avoid singularity.Moreover,it can also realize global robustness.Finally,a new kind of DO is introduced to improve the tracking accuracy.