Reusable launch vehicle control in sliding modes

Abstract

Control of a reusable launch vehicle (RLV) is considered in sliding modes. The sliding mode controllers are designed for the RLV in two operational modes: re-entry (descending) mode and launch (ascending) mode. The decentralized sliding mode controllers are designed to guarantee robust de-coupled asymptotic tracking of the Euler angles' reference profiles upon the RLV model uncertainties and external disturbances. The angular rates command vector is formed in the outer loop in order to provide an asymptotic tracking of the Euler angles' reference profiles. This command vector is tracked in the internal loop via the smoothed sliding mode controllers. Effectiveness of the designed sliding mode controllers is confirmed via computer simulations of a verticaltakeoff, horizontal-landing wing-body single-stage RLV studied at NASA Marshall Space Flight Center.