Software for Implementing Fuzzy Logic on Microcontrollers

John F. Kennedy Space Center, Florida

Fuzzy Inference System Translator (FIST) is a computer program that facilitates the implementation of fuzzy-logic software on commercial or other viable microcontrollers. In the original application for which FIST was developed, there was a need to implement plantgrowth- chamber (PGC) temperatureand- humidity controllers that had been developed within the MATLAB Fuzzy Logic Toolbox software system. In this application, fuzzy membership functions were specified for the temperature and relative-humidity signals, and a set of weighted inference rules was developed from experience and working knowledge of an environmental chamber, containing the PGC, in which the temperature and humidity were to be controlled. First-order models of PGC dynamics, based on the temperature dependences of heat-transfer rates and water-vapor pressure, were used with SIMULINK (mathematical-modeling software compatible with the MATLAB software) for rapid prototyping of a fuzzy inference system. All the information relevant to the controller thus developed are contained in a MATLAB fuzzy-inference-system file. The role of FIST in the development of the present controller or a similar controller is to extract the relevant information from this file and process it into machine code that is executable on a specified microcontroller.

This program was written by Bill Taylor of New Mexico Highlands University for Kennedy Space Center. For further information, access the Technical Support Package (TSP) free on-line at www.nasatech.com/tsp under the Software category.

In accordance with Public Law 96-517, the contractor has elected to retain title to this invention. Inquiries concerning rights for its commercial use should be addressed to New Mexico Highlands University Department of Engineering National Avenue Las Vegas, NM 87701

Refer to KSC-12145, volume and number of this NASA Tech Briefs issue, and the page number.