Trajectory control for a low-lift re-entry vehicle

Abstract

This paper presents re-entry trajectory control for a small re-entry vehicle by path following. A tracking controller restricts the vehicle to a multivariable reference trajectory defined by altitude, velocity, and flightpath angle. The controller design is based on several linear system models along a desired reference trajectory. A linear control law is designed to minimize a quadratic performance index at discrete points on the reference. Simulation results of spatial flights over a rotating Earth show that the designed controller effectively responds to entry condition offsets on several reference trajectories. Also, the controller is capable of tolerating changing vehicle parameters as well as atmospheric disturbances. The same controller gain functions are successfully applied to different reference trajectories.