An Analysis of Methods for Extracting Aerodynamic Coefficients from Test Data
Abstract
An analysis of numerical methods for extracting aerodynamic coefficients from dynamic test data has been conducted. The emphasis of the analysis is on the effects that random measurement errors in the data and random disturbances in the system have on the accuracy with which the coefficients for linear and nonlinear systems can be determined. Both deterministic and stochastic methods for extracting the coefficients and determining their uncertainties are considered. The deterministic technique considered, due to Chapman and Kirk, provides excellent estimates of both linear and nonlinear static pitching moment coefficients for the range of measurement efforts and system noise considered. Somewhat less accurate estimates of pitch damping coefficients are obtained. The stochastic approach considered demonstrates the feasibility of using an extended Kalman filter, with a parameter augmented state vector, for determining the values of the aerodynamic coefficients and their uncertainties from noisy dynamic test data. Parameter estimates obtained from the extended filter compare favorably with previously obtained results using deterministic techniques. Estimates of the parameter uncertainties provided by the filter are generally superior to those obtained with deterministic techniques particularly when system noise has corrupted the data.
Document Details
- Document Type
- Technical Report
- Publication Date
- Feb 01, 1973
- Accession Number
- AD0913508
Entities
People
- Donald C. Daniel
Organizations
- University of Florida