A novel fully-programmable analog fuzzifier architecture for interval type-2 fuzzy controllers using current steering mirrors

• Autor(a) principal: Souza, Gabriel A. F.
• Data de Publicação: 2018
• Outros Autores: Santos, Rodrigo B., Rocha Rizol, Paloma M. S. [UNESP], Oliveira, Duarte L., Faria, Lester A.
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Repositório Institucional da UNESP
• Texto Completo: http://dx.doi.org/10.3233/JIFS-171118; http://hdl.handle.net/11449/160031
• topic: Analog circuits; low-power; fuzzifier; interval type-2 fuzzy logic

A novel analog fuzzy membership function generator architecture, based on current steering mirrors, for interval type-2 fuzzy controllers is proposed in this paper. The Footprint of Uncertainty (FOU), characteristic of an interval type-2 fuzzy set, is generated by this novel architecture, which uses current steering mirrors controlled by a voltage input and allows width variation based on a central line. This main feature makes the circuit inherently type-2, i.e., not dependent of any type-1 fuzzifier, unlike all previous analog fuzzifiers found in the literature. The circuit operates in current mode and is capable of generating trapezoidal, triangular, Z-shaped and S-shaped membership functions. Input currents allow shape configuration, whereas a digitally programmable current mirror provides different inclinations, making it fully programmable (shape, width of the FOU, inclination, and position). Simulations validating the architecture were performed with TSMC CMOS 0.18 mu m technology, in CADENCE software. The circuit was later fabricated and characterized. Experimental results confirmed its ability to work as a fuzzifier, with all specified features, showing to be suitable even for dedicated low power applications.