Hostname: page-component-cd9895bd7-gxg78 Total loading time: 0 Render date: 2024-12-26T22:50:10.777Z Has data issue: false hasContentIssue false
  • English
  • Français

An equation decoupling technique for identification of unstable aircraft with unsteady aerodynamic modelling

Published online by Cambridge University Press:  04 July 2016

J. Singh  and
S. C. Raisinghani
J. Singh
Affiliation:
Indian Institute of Technology, Kanpur, India
S. C. Raisinghani
Affiliation:
Indian Institute of Technology, Kanpur, India
Get access Rights & Permissions [Opens in a new window]

Abstract

A simplified trailing vortex concept has been used to model unsteady aerodynamic effects onto the mathematical model for an augmented unstable aircraft. An output error method with, and without, an equation decoupling technique in the frequency domain has been used for the estimation of parameters. The two approaches of estimation are compared for the cases where unsteady effects are included or excluded from the estimation model. It is shown that the incorporation of the equation decoupling technique makes the estimation algorithm robust with respect to initial guess values of the parameters. Finally, the inclusion of unsteady aerodynamics is shown to reduce the variation in the parameter estimates due to different control input forms.

Type
Research Article
Information
The Aeronautical Journal , Volume 97 , Issue 969 , November 1993 , pp. 321 - 327
Copyright
Copyright © Royal Aeronautical Society 1993 

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

1. Batterson, J.G. and Klein, V. On identification of a highly augmented airplane, 7th IFAC Symposium on Identification and System Parameter Estimation, York, England, 2-8 July 1985.Google Scholar
2. Maine, R.E., and Murray, J.E. Application of parameter estimation to highly unstable aircraft, J Guid Control Dynam, May-June 1988, 11, (3), pp 213–219.Google Scholar
3. Preissler, H., and Schaufele, H. Equation decoupling — a new approach to the aerodynamic identification of unstable aircraft, J Aircr, February 1991, 28, (2), pp 146–150.Google Scholar
4. Queijo, M.J., Wells, W.R. and Keskar, D.A. Approximate indicial lift function for tapered swept wings in incompressible flow, NASA TP-1241, 1978.Google Scholar
5. Queijo, M.J., Wells, W.R. and Keskar, D.A. Inclusion of unsteady aerodynamics in longitudinal parameter estimation from flight data, NASA TP-1536, 1979.Google Scholar
6. Raisinghani, S.C. and Ghosh, A.K. Parameter estimation of an augmented aeroplane with unsteady aerodynamic modelling, Proceedings of the 17th International Symposium on Space Technology and Science, Tokyo, Japan, 20-25 May 1990, pp 699–706.Google Scholar
7. Abromiwitz, M. and Stegun, F. Handbook of Mathematical Functions with Formulas, Graphs and Mathematical Tables, Dover Publications, New York, 1965.Google Scholar
8. Maine, R.E. and Iliff, K.W. Maximum likelihood estimation of translational acceleration derivatives from flight data, J Aircr, Oct 1979, 16, (10), pp 674–679.Google Scholar
9. Jategaonkar, R.V. and Gopalratnam, G. Two complementary approaches to estimate downwash lag effects from flight data, J Aircr, Aug 1991, 28, (8), pp 540–542.Google Scholar