Use of MMLE3 to Determine Lower Order Equivalent Systems in the Time Domain.
Abstract
This thesis explains the data reduction technique for determining lower order equivalent system (LOES) parameters using flight test maneuver time history data. This technique uses MMLE3, a modified NASA-developed general program for maximum likelihood parameter estimation. MMLE3 requires a state-space model relating input to output and a time history of the input and the output. From this information, accurate estimates of the components of the state-space model can be made. The LOES parameters determined by MMLE3 would be aircraft short period frequency, damping ratio, and time delay. Based on simulation testing, it was determined that this data reduction technique was feasible and accurate. The algorithm was further tested by using flight test data gathered in a T-38. The state-space model was modified to a modified second order model, to determine basic aircraft short period frequency and damping ratio. The flight test results effectively matched the published values of frequency and short period for the T-38. Based on the results of this testing, this technique of determining LOES parameters from time history data is effective. It should be incorporated into the USAF TPS curriculum for data reduction.
Document Details
- Document Type
- Technical Report
- Publication Date
- Mar 01, 1985
- Accession Number
- ADA154700
Entities
People
- R. A. Schroeder
Organizations
- Air Force Institute of Technology