Integrated guidance and control for underactuated fixed-trim moving mass flight vehicles

Abstract

This work presents a novel real integrated guidance and control (IGC) scheme that solves the issues of underactuation, fixed-trim angle-of-attack and three-dimensional motion together for moving mass flight vehicles (MMFVs). Firstly, an underactuated IGC model containing the information of flight vehicle dynamics and three-dimensional relative motion is formulated, and the command error angle is designed to improve the capability of maneuvering penetration. Secondly, the modeled disturbances and uncertainties are regarded as the lumped disturbances, the values and derivatives of which are estimated by four second-order disturbance observers (DOs). Thirdly, different from the traditional backstepping-based partial IGC scheme, a novel sliding mode based real IGC law is designed, which generates the command moving mass offset input by only a single controller, thereby essentially eliminating the cross time-scale problem between the guidance and control loops. Moreover, this IGC law simultaneously achieves the command error angle tracking and the side-slip-angle stabilization with only a control input. Finally, the Lyapunov function is used to illustrate the asymptotic stability of the entire system, and numerical simulations with multiple disturbances, varied flying circumstances, and a comparison with other control strategies are carried out to show the effectiveness and superiority of the proposed IGC strategy.