Study On Reentry Guidance Algrithm Of Space-Based Hypersonic Vehicle

This dissertation addresses the study of reentry guidance for space-based hypersonic vehicle, including the following researches:The space-based hypersonic reentry vehicle dynamics equations have been derived. Analysis of the questions may be encountered during the reentry process. The re-entry corridor design is completed and their impact factors are analyzed. Given by considering the various re-entry constraints (heating rate flow constraints, overload constraints, dynamic pressure constraints) and the terminal constraints, a methodology for onboard Generation of Longitudinal Reentry Trajectory is studied. This methodology tranforms the constraints nonlinear trajectory design problems into one-parameter search problems. As known angle of attack, we divided the longitudinal reference trajectory into the initial descend segment and quasi-equilbrium glide condition glide segment. By searching a constant a smooth QEGC transition, to complete the design of initial descend segment. By searching the mid-point value, to complete the approximate equilibrium glide phase of the longitudinal reference trajectory, which is designed into a Piecewise linear function. Mathematical simulation showed that: the algorithm can quickly generate the flyable longitudinal reference trajectory.The space-based hypersonic reentry vehicle guidance problem is divided into the longitudinal guidance control and the lateral control. The longitudinal reference trajectory is tracked by LQR tracking controller. The lateral trajectory is controlled by heading error corridor. Set the heading angle error boundary value to change the symbols of bank angle, thus ensuring heading angle error in a smaller range. The mathematical simulation showed that the final: the tracking controller can complete the task of reference trajectory tracking; the lateral trajectory's movement was well controlled.