Robustness with a digital fuzzy logic controller

Robustness characteristics associated with a digitally implemented fuzzy logic controller are illustrated using a second-order system. Two competing performance objectives (tracking and step response) are used to design the controller. A systematic design leads to a controller that is robust with respect to both the presence of a computational time-delay and the existence of parameter variations in the system. The controller is restricted to only measure the output error signal and must accommodate a saturating system input