ITPEC FE Morning April 2020 Question 74

Fuzzy control — it works with vague, linguistic quantities such as "somewhat large" or "slightly".

Fuzzy logic lets a value belong to a set to a degree between 0 and 1 rather than simply in or out. A fuzzy controller states its rules the way a skilled operator would ("if the temperature is slightly high, turn the heater down a little"), evaluates how far each rule applies, and combines them into a precise output. Washing machines, air conditioners and camera autofocus have used it.

Answer (b)

Why not others:

• •(a) Feedback control — measures the output, compares it with a target value and corrects the difference; it works with precise measured values, not vague terms
• •(c) PWM control — varies the on-time ratio (duty cycle) of a pulse train to control the average power fed to a motor or LED
• •(d) Sequence control — carries out operations step by step in a predetermined order, as in a traffic light or washing cycle

Key rule: Match control methods by what they act on: feedback on the measured error, sequence on a fixed order of steps, PWM on pulse width, fuzzy on degrees of truth expressed in words.

Hardware · AI-written, may contain errors