Estimation of Stability & Control Derivatives from Flight Test Data of Fighter Aircraft

  • L. Saraswathi National Aerospace Laboratories, Bangalore
Keywords: Cramer Rao bounds, Fudge factor, Parameter estimation

Abstract

Longitudinal stability and tontrol derivatives of a fightlfr aircraft are estimated by output error method for different types of input excitation. The uncertainties in the parameters are computed by cortfcting Cramer-Ra(j) bounds using fudge factor. In general, the step input response data is not used
for estimating the derivatives. Therefore, step response time history trajectories were cross-validated using tIle estimated derivatives for standard inputs like doublet and 3211. This proves that the model parameters are estimated with high confidence. By appropriately choosing the mathematical model
and using the corrected flight data for bias and scale factor errors by compatability check for parameter  estimation proves beyond doubt that such a procedure can be adopted for estimating stability and control derivatives of any aircraft.


Author Biography

L. Saraswathi, National Aerospace Laboratories, Bangalore
Ms L Saraswathi obtained her MSc from Bangalore University, in 1971. fresently, she is working as Scientist at the Flight Mechanics and Control Division of the National Aerospace Laboratories (NAL), Bangalore. Her areas of work include: flight data analysis and parameter estimation of aerospace vehicle. She.is a member of the' Aeronautical Society of India.

References

Saraswathi, L. & Prabhu, M~ Estimation of stability and control derivatives from flight data of a trainer aircraft. In i t. Eng. .1: AS, 79, 1998, 15-18.

Maine, R.E. & Iliff, K. W. ARplication of

parameter estimation to aircraft stability and

control. National 'Aeronautics & Space

Administration, USA,: 1986 Report No. NASA

RP-1168.

Published
2013-01-01
How to Cite
Saraswathi, L. (2013). Estimation of Stability & Control Derivatives from Flight Test Data of Fighter Aircraft. Defence Science Journal, 50(2), 123-136. https://doi.org/10.14429/dsj.50.3366
Section
Aeronautical Systems