Self-scheduling robust pitch rate control based on multi-model eigenstructure assignment and guardian maps robustness assessment

Abstract

This paper describes a synthesis approach of a robust self-scheduled controller for the longitudinal pitch rate control system of a Bombardier Inc.'s business jet aircraft. A fixed architecture controller with five tunable gains is sought in order to satisfy a set of constraints or handling qualities in the presence of mass and center of gravity uncertainties. On a nominal flight case, a set of satisfactory gains is found using eigenstructure assignment. The robustness of the controller against the variation of the above parametric uncertainty is then tested using guardian maps. In order to improve the first controller robustness, a multi-model eigenstructure assignment is performed. A self-scheduled controller is computed to cover all mass and center of gravity variations. It is shown using Guardian Map theory that the final controller satisfies all the design criteria even when mass and center of gravity vary.