Integrated Guidance and Control for the Fixed-trim Vehicle against the Maneuvering Target

From the view of the fixed-trim reentry vehicle (FTRV) application, the integrated guidance and control (IGC) design is a key challenge. In order to improve the performance of the FTRV against the maneuvering target, an IGC system combining with the virtual target and the filter is proposed in this paper. To investigate the dynamics of the FTRV against the maneuvering target, a 7-DOF mathematical model is established and the error angle is employed to describe the relative motion between the FTRV and the target. Considering the controllability of the FTRV, a nonlinear differentiable error angle command is presented and its influence on the terminal velocity is discussed. To deal with the contradiction between the limited maneuverability and the demand of high guidance accuracy, the actual target is taken place with the virtual target, of which acceleration is estimated by the ESO. For improving the performance of the virtual target position prediction, a rolling updating strategy is proposed and derived analytically. Then, the back-stepping based IGC system is designed with the virtual target and the filter. The finite-time convergence of the IGC system is proved via the Lyapunov stability theorem. The numerical simulation results show the effectiveness of the proposed IGC system for the FTRV against the maneuvering target with time-varying acceleration.