Controller gains adjustment for closed-loop modal requirements

Abstract

This paper deals with a post-synthesis problem : how can a nominal controller be adjusted, in order to correct the assignment of some closed-loop poles? A parametric sensitivity tool, called the PRABI, is here proposed to mathematically solve this controller adjustment problem. It finds the most relevant combination of controller gains, which masters a defined modal variation. This solution is more simple if the nominal controller has a readable structure, like an observer-based structure. All these theoretical results are applied successfully to the adjustment of flight control laws of a flexible aircraft.