Identification of Aircraft Stability and Control Coefficients for the High Angle-of-Attack Regime.
Abstract
A central problem of the stall/post-stall flight regime is the identification of nonlinear aerodynamic coefficients whose adverse characteristics may produce severe handling quality degradation. This identification problem is twofold: determination of the nonlinear aerodynamic models and estimation of the coefficients of these models. An integrated parameter identification procedure based on maximum likelihood methods is presented to resolve these problems with verification results based on a nonlinear six-degree-of-freedom digital aircraft simulation. The identification procedure consists of the sequential application of a model determination algorithm and a maximum likelihood identification method. Input design and measurement system specification techniques are combined with this application to form the integrated parameter identification process. The model determination algorithm is based on least squares subset regression techniques. This structure and parameter estimation procedure is applied to the response of an advanced fighter. Results of the application of the identification procedure to these data have shown that the model structure and parameters of the nonlinear regime can be successfully identified, even in the presence of high levels of process and measurement noise. It is further shown that the estimates obtained from a data length with a given input can be used to successfully predict the response of the aircraft to another input in the same flight regime. The procedures established and verified are highly flexible and may be readily applied to modeling other classes of nonlinear vehicles from test data.
Document Details
- Document Type
- Technical Report
- Publication Date
- Mar 01, 1974
- Accession Number
- ADA032800
Entities
People
- Naman Gupta
- R. G. Smith
- W. E. Hall Jr.