Implementation of Fuzzy Systems using Micro Processors/Controllers

Abstract

This paper presents an algorithm for implementation of fuzzy systems using inexpensive general-purpose hardware. The two major difficulties encountered in implementing fuzzy systems using 8/16 bit micro processors/controllers are: (i) handling floating point arithmetic and (ii) determination of membership values. Existing membership functions (mfs) do not satisfy, simultaneously, ease in optimization and low-end hardware implementation. Mfs, recently proposed by us [1], as negative powers of 2 satisfy these two contradicting requirements. The complete algorithm for hardware implementation of the best offline design solution is described. The worst-case execution time is computed as a function of the number of inputs (m) and the number of rules (c). The performance, applicability and limitations of the proposed algorithm are illustrated using a benchmark example. Optimized fuzzy model is coded and implemented using Intel 8XC196KC 16 bit fixed point microcontroller, and the results obtained are included.

Indexing terms:

• Fuzzy logic
• Modeling
• mfs
• Digital hardware
• Optimization
• Hardware implementation

Additional information

Notes on contributors

S Himavathi

Srinivasan Himavathi is a faculty member of the Electrical and Electronics Engg Department, Pondicherry Engg College, Pondicherry, India since 1990. She pursued her doctoral programme at Anna University under QIP scheme during 1999–2002 and has submitted her thesis on Fuzzy modeling and implementation of deterministic systems. She has authored 4 journal papers and 8 Conference papers at International level. Her areas of interests include Fuzzy modeling, microprocessors, microcontrollers, and FPGA based implementation of fuzzy controllers. She is a reviewer for AMSE Journal of Modeling, France and IEEE Industrial Electronics Society.

B Umamaheswari

Bhaskaran Umamaheswari received her PhD Degree in Control systems from Anna University, Chennai in the year 1994. She has been a member of faculty with Electrical Department, Anna University from 1990. She is the author of more than 20 publications on Eigen structure assignment, Fuzzy and robot control of robot arm, Fuzzy modeling and Fuzzy tolerance. She did her postdoctoral research at Cranefield University, United Kingdom in the field of Robotics and is currently involved in the development of specialized controllers for inverters and converters.