Nonlinear Dynamical Analysis for the Control of a Reentry Vehicle in Hypersonic Flight
- Paper number
IAC-05-C1.8.06
- Author
Prof. Norihiro Goto, Kyushu University, Japan
- Year
2005
- Abstract
Trimmed atmospheric flights of existing reentry vehicles rely heavily on automatic flight control systems(AFCSs). Failures of AFCSs can easily trigger inertially coupled nonlinear motions because of their configurations. In order to devise a remote control technique for recovering a level flight from such a nonlinear motion, it is mandatory to understand 1) equilibrium points of the bare vehicle in flight without AFCSs, 2) asymptotic behaviors of the solutions near an equilibrium point, and 3) control laws that take advantage of the knowledge of 1) and 2). The paper provides a methodology for the analysis of 1) and 2), and proposes a design concept for 3), taking the Japan’s reusable orbiting spacecraft HOPE-X in hypersonic flight as an example. Obtained results are as follows: 1. Improvements have been made of the method for analyzing equilibrium branches using the continuation method; a new technique is devised to make an initial guess of a point of departure for tracking an equilibrium branch; and a refined numerical technique is proposed in utilizing the continuation method. 2. Flight dynamical properties of the HOPE-X in hypersonic flight have been made clearer: The shape of equilibrium branches at hypersonic speeds differs much from that at subsonic speeds due to aerodynamics; and equilibrium points of the HOPE-X in hypersonic flight are stabilized by taking account of aerodynamic damping moments such as Cmq and Clp in the linear sense for a range of elevator angles, outside of which equilibrium points are hyperbolic, mostly saddle points. 3. A chaotic recovery control technique is proposed that makes use of a stable manifold of a saddle point. In conclusion this work contributes significantly to understanding the nonlinear motions and their control of a reentry vehicle in hypersonic flight, which has been insufficient in the past literature. The paper was not presented at a previous meeting, and financing and attendance of an author at the 56th IAC in Fukuoka to present the paper is assured.
- Abstract document
- Manuscript document
IAC-05-C1.8.06.pdf (🔒 authorized access only).
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