The fuzzy systems with variable universe of discourse (VUD) have received increasing attention due to their fine control performance. VUD fuzzy systems are ones in which universes of discourse can be online tuned by means of a set of nonlinear contraction expansion factors. One advantage of the VUD fuzzy systems lies in that higher control accuracy can be obtained without the aid of integral elements. Another advantage of the VUD fuzzy systems is that the number of fuzzy rules can be reduced significantly for a given application, compared with the fuzzy system based on fixed universes of disco...
