Inner loop control of supersonic aircraft in the presence of aeroelastic modes

Author

Joshi, S.M. ; Kelkar, A.G.

Author_Institution

NASA Langley Res. Center, Hampton, VA, USA

fYear

1996

fDate

15-18 Sep 1996

Firstpage

130

Lastpage

135

Abstract

Longitudinal control system design is considered for a linearized dynamic model of a supersonic transport aircraft concept characterized by relaxed static stability and significant aeroelastic interactions. Two LQG-type controllers are designed using the frequency-domain additive uncertainty formulation to ensure robustness to unmodeled flexible modes. The first controller is based on a 4th-order model containing only the rigid-body modes, while the second controller is based on an 8th-order model that additionally includes the two most prominent flexible modes. The performance obtainable from the 4th-order controller is not adequate, while the 8th-order controller is found to provide better performance. Frequency-domain and time-domain (Lyapunov) methods are subsequently used to assess the robustness of the 8th-order controller to parametric uncertainties in the design model

Keywords

aircraft control; control system synthesis; frequency-domain analysis; linear quadratic Gaussian control; robust control; time-domain analysis; 4th-order model; 8th-order model; LQG-type controllers; Lyapunov methods; aeroelastic modes; frequency-domain additive uncertainty formulation; inner loop control; linearized dynamic model; longitudinal control system design; parametric uncertainties; relaxed static stability; rigid-body modes; robustness; supersonic aircraft; Aerodynamics; Aerospace control; Aircraft; Eigenvalues and eigenfunctions; Hydrogen; Open loop systems; Stability; Transfer functions; Uncertainty; Upper bound;

fLanguage

English

Publisher

ieee

Conference_Titel

Control Applications, 1996., Proceedings of the 1996 IEEE International Conference on

Conference_Location

Dearborn, MI

Print_ISBN

0-7803-2975-9

Type

conf

DOI

10.1109/CCA.1996.558619

Filename

558619