Abstract
The fuzzy logic control of mechanical systems with periodic coefficients is considered. The controller design is illustrated through two examples, which include linear as well as nonlinear systems. For the linear case, a controller is designed such that a single inverted pendulum with a time periodic follower force is stabilized in the vertical position. As an example of the nonlinear system, the flap motion of a parametrically excited rotating elastic beam is considered. The controller is designed such that the deflection of the beam tip vanishes in a short period of time.