Gupo de Trabajo en Electrónica Analógica y Mixta

Design and Application of High Complexity Mixed-Signal Integrated Neuro-Fuzzy Controllers

TESIS DOCTORAL

Rafael de Jesús Navas González

Advisor: Dr. Fernando Vidal Verdú

Departamento de Electrónica
Universidad de Málaga

ABSTRACT:

The main contributions of this Thesis focuse on the analog and mixed-signal integrated circuits design and the application field of neuro-fuzzy systems, and its aim is preserving most of the advantages of the analog implementations of fuzzy controllers, while allowing a notorious increment of the system complexity.

Specifically, a new architecture for neuro-fuzzy controllers is proposed to accomplish a spatial multiplexed strategy of an analog core which implements the simplest fuzzy system in each subregion of the input space. This core provides the output, for a given input vector, and from the active rules set in each subregion of input space, as rule base, which could be called the real rule set. In order to provide an output for any input value, and fulfil the whole control surface, such core is multiplexed among the whole knowledge base which is composed by the virtual rule set. The latter is actually just a set of programming parameters stored in digital and analog memories, and the multiplexing is realized by means of digital techniques. Thus, the signal path is entirely analog, while the internal control circuitry is mixed, thus the analog performances are preserved.
To validate this proposal, a monolithic controller has been implemented in standard CMOS 0.7mm technology. This example controller has two inputs, one output and sixty-four rules, much more than the reported pure analog monolithic fuzzy controllers, while preserves most of their advantages. Experimental results from that example implementation are presented to show its major features.
Finally, to illustrate the capabilities of the fuzzy controller chip in a real application, a DC motor soft-start procedure has been proposed and developed. This is an original application, not previously reported and it is complex enough to show the performances of the controller when it is forced to work in a high-speed control loop.

Last Update: June, 2007