Abstract
Fuzzy control systems are analyzed from the control engineering viewpoint and possibility of their industrial applications is investigated. First, the mathematical model of a fuzzy controller which uses symmetric triangular membership functions and direct inference is derived. Then, the fuzzy control system of inverted pendulum which is often used in demonstration is analyzed, and it is shown that the pendulum falls down after a certain time. Based on the control theory, it is inferred that the pendulum will be balanced if PI element is inserted into the loop of the angle of the pendulum, and this inference is proved to be correct. The above phenomena are explained by applying linear stability theory. Lastly, possibility of industrial applications of fuzzy controllers is investigated.
