Nonlinear Parameter Identification: Lift Coefficient, Drag Coefficient, and Bank Angle Histories for the Space Shuttle Test Flight I.
Abstract
A nonlinear, Square-Root Variable-Metric optimization technique is used to extract time histories for the lift coefficient, drag coefficient, and bank angle control variables from radar data of the Space Shuttle Test Flight. This optimization technique solves for these control variable histories by minimizing a weighted least squares performance index of the calculated versus experimental state equation time histories. The state model is a three degree of freedom representation of aircraft motion. Three intervals of data are evaluated. In each interval, polynomial functions represent the control variables, and the performance index is dependent only on the values of the polynomial coefficients. The larger of the first two intervals contained the shorter interval so that the effect of changing polynomial order and interval length could be explored. The third interval compared the calculated parameter histories with NASA's BET parameter histories with good correspondence. For all three intervals the calculated state histories closely matched the experimental state histories. These results show that given an appropriate state model, this optimization technique is useful for quickly obtaining good and inexpensive estimates of certain desired parameters. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Dec 01, 1981
- Accession Number
- ADA111121
Entities
People
- Harry Francis Johnson
Organizations
- Air Force Institute of Technology