Partial-jet-borne flight LQG/LTR robust controller design

A research was done for the problem of the application of integrated flight/propulsion system of the aircraft using LQG/LTR (linear quadratic gaussian/loop transfer recovery) robust design methodology at the partial-jet-borne flight phase. With flying qualities assessed by bandwidth and Gibson criteria, and the robustness assessed by singularity values, the rule of choosing LQG/LTR design parameters was analyzed, including several influential factors, such as allocation of the attitude and rate command, effects of prefilters, presetting of disturbance level factor and effects of high frequency dynamics on the robustness and flying qualities. The controller design on a test aircraft configuration shows that compromise can be made between flying qualities and robustness by designing LQG/LTR robust controller, if the response type parameter and the disturbance level factor are suitably chosen.