Date of Award


Document Type


Degree Name

Master of Science in Aeronautical Engineering


Department of Aeronautics and Astronautics

First Advisor

D. Brett Ridgely, PhD


A general mixed H2/H optimal control design with multiple H constraints is developed and applied to two systems, one SISO and the other MIMO. The SISO design model is normal acceleration command following for the F- 16. This design constitutes the validation for the numerical method, for which boundaries between the H2 design and the H constraints arc shown. The MIMO design consists of a longitudinal aircraft plant (short period and phugoid modes) with stable weights on the H2 and H transfer functions, and is linear- time-invariant. The controller order is reduced to that of the plant augmented with the H2 weights only. The technique allows singular, proper (not necessarily strictly proper) H constraints. The analytical nature of the solution and a numerical approach for finding suboptimal controllers which are as close as desired to optimal is developed. The numerical method is based on the Davidon- Fletcher-Powell algorithm and uses analytical derivatives and central differences for the first order necessary conditions. The method is applied to a MIMO aircraft longitudinal control design to simultaneously achieve Nominal Performance at the output and Robust Stability at both the input and output of the plant.

AFIT Designator


DTIC Accession Number