A fuzzy control system is a control system based on fuzzy logic a mathematical system that analyzes analog input values in terms of logical variables that take on continuous values between 0 and 1, in contrast to classical or digital logic, which operates on discrete values of either 1 or 0 (true or false, respectively)

that analyzes analog input values in terms of logical variables that take on continuous values between 0 and 1, in contrast to classical or digital logic, which operates on discrete values of either 1 or 0 (true or false, respectively)

Fuzzy logic is widely used in machine control. The term “fuzzy” refers to the fact that the logic involved can deal with concepts that cannot be expressed as the “true” or “false” but rather as “partially true”. Although alternative approaches such as genetic algorithms and neural networks can perform just as well as fuzzy logic in many cases, fuzzy logic has the advantage that the solution to the problem can be cast in terms that human operators can understand, so that their experience can be used in the design of the controller. This makes it easier to mechanize tasks that are already successfully performed by humans

Fuzzy logic was first proposed by DR. Lotfi A. Zadeh of the University of California at Berkeley in a 1965 paper. He elaborated on his ideas in a 1973 paper that introduced the concept of “linguistic variables”, which in this article equates to a variable defined as a fuzzy set. Other research followed, with the first industrial application, a cement kiln built in Denmark, coming on line in 1975

Lotfi Aliasker Zadeh ( February 4, 1921 – September 6, 2017) was a mathematician, computer scientist, electrical engineer, artificial intelligence researcher and professor emeritus of computer science at the University of California, Berkeley. Zadeh was best known for proposing fuzzy mathematics consisting of these fuzzy-related concepts: fuzzy sets, fuzzy logic, fuzzy algorithms, fuzzy semantics, fuzzy languages, fuzzy control, fuzzy systems, fuzzy probabilities, fuzzy events, and fuzzy information

Zadeh was born in Baku, Azerbaijan Soviet Socialist Republic, as Lotfi Aliaskerzadeh, to an Iranian Azerbaijani father from Ardabil, Rahim Aleskerzade, who was a journalist on assignment from Iran, and a Russian Jewish mother, also an Iranian citizen, Fanya Korenman, who was a pediatrician from Odessa. The Soviet government at this time courted foreign correspondents, and the family lived well while in Baku. Zadeh attended elementary school for three years there, which he said “had a significant and long-lasting influence on my thinking and my way of looking at things.” In 1931, when Zadeh was ten years old, his family moved to Tehran in Iran, his father’s homeland. Zadeh was enrolled in Alborz College, which was a Presbyterian missionary school, where he was educated for the next eight years, and where he met his future wife, Fay. Zadeh says that he was “deeply influenced” by the “extremely decent, fine, honest and helpful” missionaries from the United States who ran the college. “To me they represented the best that you could find in the United States – people from the Midwest with strong roots. They were really ‘Good Samaritans’ – willing to give of themselves for the benefit of others. So this kind of attitude influenced me deeply. It also instilled in me a deep desire to live in the United States.” During this time, Zadeh was awarded several patents

Despite being more fluent in Russian than in Persian, Zadeh sat for the national university exams and placed third in the entire country. As a student, he ranked first in his class in his first two years. In 1942, he graduated from the University of Tehran with a degree in electrical engineering, one of only three students in that field to graduate that year, due to the turmoil created by World War II, when the United States, Britain and the Soviet Union invaded Iran, whose ruler, Reza Shah, was pro-German. Over 30,000 American soldiers were based there, and Zadeh worked with his father, who did business with them as a contractor for hardware and building materials. In 1943, Zadeh decided to emigrate to the United States, and traveled to Philadelphia by way of Cairo after months of delay waiting for the proper papers or for the right ship to appear. He arrived in mid-1944, and entered the Massachusetts Institute of Technology (MIT) as a graduate student later that year. While in the United States, he changed his name to Lotfi Asker Zadeh. He received an MS degree in electrical engineering from MIT in 1946, and then applied to Columbia University, as his parents had settled in New York City. Columbia admitted him as a doctoral student, and offered him an instructorship as well. He received his Ph.D. in electrical engineering from Columbia in 1949, and became an assistant professor the next year. Zadeh taught for ten years at Columbia, was promoted to Full Professor in 1957, and taught at the University of California, Berkeley from 1959 on. He published his seminal work on fuzzy sets in 1965, in which he detailed the mathematics of fuzzy set theory. In 1973 he proposed his theory of fuzzy logic

Zadeh was called “quick to shrug off nationalism, insisting there are much deeper issues in life”, and was quoted as saying in an interview: “The question really isn’t whether I’m American, Russian, Iranian, Azerbaijani, or anything else. I’ve been shaped by all these people and cultures and I feel quite comfortable among all of them.” He noted in the same interview: “Obstinacy and tenacity. Not being afraid to get embroiled in controversy. That’s very much a Turkish tradition. That’s part of my character, too. I can be very stubborn. That’s probably been beneficial for the development of Fuzzy Logic.” He described himself as “an American, mathematically oriented, electrical engineer of Iranian descent, born in Azerbaijan.” Zadeh was married to Fay Zadeh and had two children, Stella Zadeh and Norman Zada. Zadeh died in his home in Berkeley, California, on September 6, 2017, at the age of 96. He is buried in the first Alley of Honor in Baku, Azerbaijan, where he was born. His funeral was well attended by “highly respected people”, including the president of Azerbaijan. A month previous to his death, the University of Tehran had released an erroneous report that Zadeh had died, but withdrew it several days later

According to Google Scholar, as of September 2017, Zadeh’s work has been cited about 180,000 times in scholarly works, with the 1965 “Fuzzy Sets” paper receiving about 90,000 citations

Zadeh, in his theory of fuzzy sets, proposed using a membership function (with a range covering the interval [0,1]) operating on the domain of all possible values. He proposed new operations for the calculus of logic and showed that fuzzy logic was a generalisation of classical and Boolean logic. He also proposed fuzzy numbers as a special case of fuzzy sets, as well as the corresponding rules for consistent mathematical operations (fuzzy arithmetic)

Zadeh is also credited, along with John R. Ragazzini, in 1952, with having pioneered the development of the z-transform method in discrete time signal processing and analysis. These methods are now standard in digital signal processing, digital control, and other discrete-time systems used in industry and research. He was an editor of the International Journal of Computational Cognition

Zadeh was a Fellow of the Institute of Electrical and Electronics Engineers, the American Academy of Arts and Sciences, the Association for Computing Machinery, the Association for the Advancement of Artificial Intelligence and the International Fuzzy Systems Association, and a member of the National Academy of Engineering. He was also a member of the Academies of Science of Azerbaijan, Bulgaria, Finland, Korea and Poland, and of the International Academy of Systems Studies in Moscow. He has received 24 honorary doctorates