Accession Number : ADA140462

Title :   Bifurcation and Feedback in Aircraft Dynamics.

Descriptive Note : Final technical rept. 1 Dec 81-30 Sep 82,

Corporate Author : SCIENTIFIC SYSTEMS INC CAMBRIDGE MA

Personal Author(s) : Baillieul,J ; Levi,M ; Mehra,R K

PDF Url : ADA140462

Report Date : 31 Oct 1982

Pagination or Media Count : 38

Abstract : Modern qualitative theory of differential equations originated with the work of Poincare, who essentially had arrived at the phenomenon which is presently called Hopf bifurcation. Poincare's work was later developed by Androuov and Pontryagin and Hopf. More recently, experience with the aircraft at high angles of attack shows loss of stability for some critical values of parameter (e.g., angle of attack, or the velocity). This phenomenon was interpreted by Mehra et al. as the Hopf bifurcation; this interpretation was supported by numerical study for the aircraft H model. The work of Mehra et al. led naturally to the question as to the effect of control decoupling feedback on the (undesirable) Hopf bifurcation; in particular, does such a feedback eliminate the bifurcation? Among other things, this question is answered in this report.

Descriptors :   *Aircraft models, *Bifurcation(Mathematics), *Aerodynamic stability, Decoupling, Feedback, High angles, Angle of attack, Velocity, Geometry, Flight control systems

Subject Categories : Aerodynamics
      Theoretical Mathematics
      Fluid Mechanics

Distribution Statement : APPROVED FOR PUBLIC RELEASE