Information Approach to Fixed-Gain Design

A method for designing fixed-gain controllers and filters for systems with large parameter variation is presented. The approach is based on finding the minimax point of the Kullback information measure between the fixed-gain system and the optimal system at a given operating point. The effectiveness of the proposed approach is illustrated by designing a fixed-gain system for the short-period control of a high-performance aircraft and evaluating its performance over the flight envelope.