Sliding mode control of reusable launch vehicle in launch and re-entry modes

Abstract

Trajectory control for a reusable launch vehicle (RLV) is considered for two operational modes: reentry and launch modes are considered. Decentralized sliding mode controllers are designed to achieve the de-coupled asymptotic tracking of Euler angles' profiles upon plant uncertainties and externul disturbances. Two sliding mode control strategies are investigated: direct Euler angles' profiles tracking and angular rates tracking in combination with a coordinated turn inversion. Efectiveness of the sliding mode controllers is confirmed hy simulations of a trajectory tracking for the WBOOl RLV studied at NASA Marshall Space Flight Center. perturbations lead to the payload weight reduction launched to the orbit. From the control point of view it requires development of robust control algorithm that can automatically adjust to some changes in mission specifications and the operating environment. Various linear [3] and nonlinear guidance and trajectory control algorithms [4] were used. One of the effectme control strategies successfully applied in nonlinear systems is the Sliding Mode Control [S-71. The main advantage of the Sliding Mode Control is that the system's state response remains insensitive to parameter variaitions and disturbances in the sliding surface. The W13001 RLV trajectory tracking is addressed via the dle-coupling sliding mode control [S-91. Problem Formulation 1. IntroductionThe current research in developing a next generation launch vehicle is focused on reusable launch vehicles (RLV). The one-stage-to orbit RLV developing in X-33 project will replace the aging Space Shuttles at the beginning of the next century [l]. One proposed configuration for a RLV vehicle is a vertical-takeoff, horizontal-landing wing-body single-stage vehicle (WB001) [2]. The reentry control problem consists in automatic controlling the atmospheric entry trajectory which can be precalculated or generated in current time by guidance algorithms. The launch control problem consists of automatic tracking the given launch trajectory. For present launch systems the launch trajectory has to be remodeled for each mission, depending on the weight of the payload as well as the prescribed orbit and safety margins. Errors in optimal launch trajectory tracking caused by variousThe following model of a rigid RLV is taken. Orientation equations of a rigid RLV are given 1.in terms of Euler angles w, 0, cp (b = p + q tan0 sincp + r tan0 cos9The equations of an RLV rotational motion are q . 1 = -[-pr(J, -JU)-JX(p2 -r2)+ MI]

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

“…To proceed, the next concern is the attitude tracking controller design. It is challenging for the attitude tracking controller design of RLV in reentry phase, 2,3 since the altitude and Mach number vary from atmospheric entry at hypersonic speed to subsonic approach and landing, the dramatical changes of aircraft dynamics. There is much research on attitude control system design, 4 backstepping control, 5,6 sliding mode control (SMC), 7,8 trajectory linearization control (TLC), 9,10 dynamic inversion technique (DI), 11,12 state-dependent Riccati equation strategy (SDRE), 13,14 and theta-D control.…”

Disturbance observer-based sliding mode backstepping control for a re-entry vehicle with input constraint and external disturbance

“…Re-entry tracking control is very challenging, as the vehicle dynamics change dramatically as the altitude and Mach number vary from atmospheric entry at hypersonic speed to subsonic approach and landing (Shtessel and Krupp, 1997). Therefore, the focus of this paper is to design an attitude control system to track the guidance command.…”