Identification of integro-differential systems for application to unsteady aerodynamics and aeroelasticityIntegrodifferential equations for unsteady aerodynamic and aeroelastic phenomena are identified by means of several approaches. When the product of the frequency of motion and maximum time delay is much smaller than unity, the integral term can be approximated by a constant; when greater than unity, however, approximation of the integral is not possible. Approximations of integrodifferential models are needed to obtain identifiability. While the least-squares method may be used for model determination, the maximum likelihood technique is needed for accurate parameter estimation. High angle of attack and post stall/spin regions appear to have characteristics that can be satisfied by indicial models.
Document ID
19850061677
Acquisition Source
Legacy CDMS
Document Type
Conference Paper
Authors
Gupta, N. K. (Integrated Systems, Inc. Palo Alto, CA, United States)
Iliff, K. W. (NASA Flight Research Center Edwards, CA, United States)