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Harnessing fuzzy logic

Wednesday, May 10, 2006
Myrna Anderson

A 17c起草社区 senior engineering student had a rare opportunity for an undergraduate when he presented a paper on 鈥渇uzzy logic鈥 at the 2006 , held May 7-10, at Michigan State University鈥檚 Kellogg Center.

The event was sponsored by the Institute of Electrical and Electronics Engineers (IEEE), Inc. He originally wrote his paper for a student contest and then submitted it to the IEEE conference.

鈥淚 didn鈥檛 think they鈥檇 select it,鈥 he said.

Bryan Klingenberg spoke on 鈥淔uzzy Logic for Harmonic Distortion Diagnosis in Power Systems鈥 at the conference, whose keynote speaker was the inventor of fuzzy logic.

鈥淚t is a prestigious conference,鈥 said 17c起草社区 engineering professor Paulo Ribeiro. 鈥淚 think this is a remarkable opportunity for a student.鈥

Klingenberg, who will graduate May 20, has also designed a Web site for teaching fuzzy logic to undergraduates, an effort funded by the Digital Studio at 17c起草社区.

His current work will be used by Ribeiro in his work on shipboard power systems for the new class of U.S. Navy ships, sponsored by the Office of Naval Research.

鈥淏ryan鈥檚 work is all the more impressive because it is going into industrial application at the research level right away,鈥 Ribeiro said.

Fuzzy logic is a system that uses several inputs, not just one, to make a decision.

鈥淚t functions almost like a human,鈥 Ribeiro said. 鈥淥ur decisions are very fuzzy. You don鈥檛 decide I鈥檓 going to do this for one simple reason. We are always thinking in a fuzzy way and making decisions based on multitude of inputs or data information.鈥

鈥淵ou use it for control of a system,鈥 added Klingenberg. 鈥淐ommon applications of fuzzy logic are anti-lock brakes, heating, ventilation and air conditioning. There鈥檚 a subway system in Japan that is completely controlled by a fuzzy controller.鈥

Ribeiro described how fuzzy logic works in anti-lock braking systems: 鈥淭here is a certain frequency that is more appropriate to bring the car to a stop depending on the speed of the car, the temperature and the humidity of the air. There鈥檚 a computer in the system that automatically calculates those things to choose the correct frequency for braking.鈥

Klingenberg used fuzzy logic to diagnose harmonic distortion in power systems.

鈥淗armonic distortions are extra, unwanted oscillations in the signal that can adversely affect many systems by causing erratic behavior and overheating-either immediate equipment failure or shortened equipment life,鈥 he said. 鈥淪o, you have something that鈥檚 supposed to last for 10 years, and it lasts for five years, or it will just blow up.鈥

The model devised by Klingenberg uses a fuzzy logic-based controller to monitor temperature and several harmonic voltage inputs, which indicate the degree of danger that the system is under.

Klingenberg first worked on fuzzy logic as a project through Ribeiro鈥檚 class.

鈥淚 knew that I wanted to study this,鈥 Ribeiro said, 鈥渂ut I needed someone to help me with it. He did most of the work on his own. That was the remarkable thing. I was impressed with how he was able to accomplish this on his own.鈥

Klingenberg went on to create the website for Digital Studio.

Headlining the IEEE conference, a forum for researchers and practitioners in academia and industry, was Dr. Lotfi Zadeh, the man who in 1965 invented fuzzy logic.

鈥淎t the time, it wasn鈥檛 very well accepted-the applications of his theory-at least in the west. In the east, in Japan, they took fuzzy logic and ran with it and made tons of applications,鈥 Klingenberg said.

The Institute of Electrical and Electronics Engineers (IEEE) is the world's largest technical professional society. Founded in 1884 by a handful of practitioners of the new electrical engineering discipline, today's Institute is comprised of more than 320,000 members who conduct and participate in its activities in 152 countries.