Fuzzy Static Output Feedback May Be Possible in LMI Framework

Takagi-Sugeno (T--S) fuzzy-model-based static output-feedback controller design is a challenging issue due to the nonconvexity in the Lyapunov stability condition. Recently, a convexified linear matrix inequality (LMI) condition was proposed for the problem by additionally importing as many equality constraints as the number of the fuzzy rules with a variable in the paper from the study of Fang et al. However, numerical experiences seem to imply the infeasibility of the proposed LMI. This letter shows that their LMI problem may be feasible.