Nonlinear H∞ output feedback control for linear systems using nonlinear weight

In this paper, the nonlinear H_∞ output feedback control problem for linear systems with nonlinear weight is considered. In other words, the state equation of the generalized plant is linear, and the equation of controlled output is nonlinear. Previously, Kubota et al. (1996) showed that if one could control the system by the state feedback, the solvable condition of this system was given by the algebraic Riccati equation under some constraints on the nonlinear weight, and derived a state feedback controller. This paper extends the scheme to an output feedback. This result is a little conservative, but a nonlinear controller gives better performance than a linear one as shown in the numerical example