Suboptimal Output Feedback Control Design for T-S Fuzzy Systems with Persistent Bounded Disturbances and Immeasurable Premise Variables

ُSaid Hoghoughi Esfahani¹

1) Assistant Professor, Ph.D.

Publication : 2nd International Conference on Engineering and Applied Science(2iceasconf.com)
Abstract :
This paper is concerned with the problem of suboptimal output feedback steady-state L-hnfinity -gain control design for nonlinear systems under the effects of persistent bounded disturbances. The initial nonlinear system is approximated by a suitable T-S fuzzy model. It is assumed that the information of premise variables in the T-S fuzzy model is not accessible through the measurement equations. In contrast to the existing results in the literature, the controller in this paper does not have an observer-based structure. Moreover, it is not in the form of a Parallel Distributed Compensation (PDC) control laws. In this paper, the T-S fuzzy model is first transformed to an equivalent linear uncertain system. The control problem is then formulated in the form of a single robust steady-state L-infinity -gain control law for the uncertain system. The single controller can be easily found by a search over the solutions of two Linear Matrix Inequalities (LMIs). However, four positive scalars should be determined in advance. Hence, a particular numerical method is developed to find the feasible solutions. Moreover, the numerical method can be easily extended to find the suboptimal control law. One illustrative example shows the effectiveness of the obtained results.
Keywords : L-infinity -gain control T-S fuzzy systems Persistent bounded disturbances Immeasurable premise variables Robust control.