Comparison of PID and Fuzzy PID Controller for a Linearised Magnetic Bearing

This paper is a presentation of a linear model of a magnetic bearing and a comparison of two controllers concerning their control performance. Initially, the benefits obtained by the use of magnetic bearings in the electromechanical systems are presented. Afterwards, the necessity for a suitable controller design is discussed in terms of the instability of the open loop system. Looking for a suitable control manner, a controller that behaves non-linearly, such as a fuzzy PID controller has been chosen in this paper. The use of such a non-linear controller improves both the results and the range of its use of the above system. The linear and the Fuzzy PID controller are compared using extensively simulation tests with the existence of white noise signal. The results of these comparisons, concerning the stability of these controllers are discussed and presented.