Optimal H∞ Output Feedback Control for a Class of Nonlinear Systems

This paper discusses optimal H-infinity output feedback control using linear matrix inequalities for a class of systems with sector bounded nonlinearities. A unified model, which is the interconnection of a linear dynamic system and a sector bounded static nonlinear operator, is proposed to describe these systems. Based on the H-infinity performance analysis of the closed-loop systems including the unified model and output feedback controller, the parameters of output controller are determined not only to guarantee global asymptotic stability of the closed-loop system without disturbances, but also to reduce the effect of external disturbance on the performance output to a minimal H-infinity norm constraint. The nonlinear systems satisfying certain sector type constraints can he transformed into this unified model, and H-infinity output feedback controllers are designed for these systems in a unified way.