Definition - What does Fuzzy Set mean?
A fuzzy set is the group of numbers that make up the operational parameters used by control systems that allow machinery to perform within limits, rather than clinging to a single, specific setting. These controls, called fuzzy logic controllers, use the overlap of two or more of these sets (groups of numbers) to guide drills, control motor speeds, react to conditions within a bore or otherwise provide the most efficient operation of a system.
Trenchlesspedia explains Fuzzy Set
When an insurance estimator looks at a damaged vehicle, he or she knows the range of repair costs for each separate part, some obvious and others hidden from view, damaged by an accident. The estimator knows the price range of each part that requires repair or replacement. These two ranges (the cost of repair and the cost of parts) are fuzzy sets and the intersection of the two sets will form the estimator's "best guess" about the cost of returning your vehicle to operating condition.
The fuzzy sets used in trenchless machine controls are similar. They are mathematical ranges within which the machine will operate best in a set of given situations. The fuzzy logic controller uses the fuzzy sets with which it's programmed to determine the "best guess" for optimum performance.