Finite-time attitude tracking control design for reusable launch vehicle in reentry phase based on disturbance observer

Abstract

For the attitude tracking control problem of reentry reusable launch vehicle in reentry phase, a disturbance observer–based sliding mode controller is proposed in this article. At first, attitude model is decomposed into two loops on the basis of the engineering backgrounds of reusable launch vehicle and the multiple time-scale technique. Then, external disturbances and uncertainty are estimated by the disturbance observer, and sliding mode control scheme in the framework of backstepping technique is designed where sliding surfaces and sliding mode controllers are, respectively, designed for each loop. Based on Lyapunov stability theory, finite-time stability analysis is presented, in which attitude tracking error converges to the neighborhood around zero in finite time. Finally, simulations on the 6-degree-of-freedom reentry model are done to show the effectiveness of the proposed control scheme.