Nonlinear Disturbance Observer-Based Attitude Tracking Control for Near Space Morphing Vehicle

This paper presents the design of multi-model switching attitude control problem of near space morphing vehicle (NSMV) in the presence of external disturbance and uncertainties, by applying the disturbance observer technique and finite-time sliding mode control scheme. Considering compound disturbances as well as the influence of model uncertainties and unknown external disturbance, the dynamic equations and kinematic equations of NSMV are given firstly. In order to obtain the estimation information of the disturbance quickly and accurately, a series of disturbance observers have been developed. According to the estimation information, the finite-time tracking control scheme is developed by adopting the terminal attractor. Moreover, the input saturation constraint is overcome via introducing an auxiliary variable to compensate for the overshooting. The Lyapunov theory is used to analyze the stability of the closed-loop attitude systems. Finally, simulation results for the attitude dynamics models show the feasibility of the proposed control scheme.