Simulation of a fuzzy-logic control system

The paper reviews fuzzy-control principles and shows a simulation program permitting convenient generation of membership functions and simple output interpolation. Interactive simulation is more than ordinarily important for economical fuzzy-controller design, which must reduce the number of membership classes and input/output rules as much as possible. The paper uses a personal computer and inteactive editing to compare linear and fuzzy servo controllers. With 50 per cent class-membership overlap {‘pseudo dither’), the present fuzzy logic produces linear interpolation, and thus completely unimpaired servo performance even if it uses only 2 fuzzy sets (‘positive’ and ‘negative’) each for error and output rate.