Flight Control Design using Mixed H\u3csub\u3e2\u3c/sub\u3e/µ Optimization

This thesis examines the use of the mixed H2-Microns optimal control synthesis method in the design of a flight control system for the lateral-directional axes of the F-16 Variable Stability In-Flight Simulator Test Aircraft (VISTA). The method is designed to minimize the H2 norm (two-norm) for a given value of microns. This should provide adequate noise and disturbance rejection while maintaining robustness against several types of uncertainties in the system. This thesis finds that, for this problem, the two-norm is not an accurate representation of the outputs of interest. When the two-norm is broken up into its constituent parts an appropriate solution can be found. This thesis also finds that it is possible to use an H2 controller which is destabilizing to the evaluation model as the starting point in the mixed H2-IL curve and still get an acceptable answer. A numerical approach was used, utilizing a recently improved computer algorithm