Comment on 'evolutionary design of static output feedback controller for Takagi-Sugeno fuzzy systems'

In this note, a problem that must be paid attention to is highlighted here on using the sector non-linearity in the fuzzy model construction. The sector non-linearity approach can guarantee an exact fuzzy model construction. However, it needs carefully checking to prevent that the physical constraints are violated when the sector non-linearity approach is used. Based on the exact fuzzy model obtained from the sector non-linearity approach, an approach of designing static output feedback controller is presented in a recent study. However, it can be found that the designed control result is erroneous in that published study, owing to that a physical constraint is violated.