Bifurcation Analysis of the Longitudinal Dynamics of a Simple Powered Lifting Hypersonic Vehicle
Abstract
Bifurcation analysis was used to investigate the nonlinear behavior of a simple powered lifting hypersonic vehicle in circular orbit about a spherical nonrotating Earth with gradients in atmospheric density and pressure and an inverse square law for gravity. Vehicle motion is constrained to a vertical plane so only longitudinal dynamics were modeled. Bifurcation analysis was conducted using the AUTO software package. A simple five-state model with three different thrust laws was derived to describe an unaugmented vehicle whose geometric and aerodynamic characteristics follow those of the literature. A parameter representing a body flap deflection was used to conduct one set of bifurcation sweeps for each thrust law. A second set of bifurcation sweeps for each thrust law was obtained using a parameter representing a throttle which scaled the thrust. Secondary parameters representing simple feedback gains were subsequently added. Results were surprising for a simple system with basically linear aerodynamics . Periodic branches arising from the loss of pitch stability or associated with a resonance altitude are routinely found with significant amplitude, and periods on the order of an elliptical orbit's period for a given geocentric radius. Rotational states generally had sub-oscillations of greater frequency.
Document Details
- Document Type
- Technical Report
- Publication Date
- Dec 01, 1990
- Accession Number
- ADA230826
Entities
People
- Eric E. Fox
Organizations
- Air Force Institute of Technology