Abstract
A New H∞ control theory which uses a plant description of the normalized left coprime factorization (NLCF) is applied to a pitch attitude control of the short period mode of airplanes. In this theory, the selection of pre and/or post compensators called shaping functions is of practical importance to determine the closed-loop characteristics. This paper presents that the closed-loop poles determined by the theory are given as the eigenvalues of two matrices, one for the augmented plant poles and the other for the controller poles. It is shown as well that the closed-loop poles of the augmented plant are the same as those of the linear quadratic regulator (LQR) theory. These properties enable us to design a compensator that takes not only frequency domain properties (e. g. robustness) but also time domain ones (e. g. output step response) into consideration. Some trade-off is necessary between robustness and fast, less overshooted output responses.
