Design and implementation of a reduced rule fuzzy logic PID controller

This paper investigates the design and implementation of a reduced rule PID fuzzy logic controller. Fuzzy logic PD and PI controllers are effective for many control problems but lack the advantages of the fuzzy PID controller. Fuzzy controllers use a rule base to describe relationships between the input variables and output. Implementation of a detailed rule base increases in complexity as the number of input variables grow. For example, a PID controller with three inputs needs 343 (7*7*7) rules if each input has 7 fuzzy sets. The implementation of a controller with such a large rule base is a tedious task. We propose a reduced rule fuzzy logic PID controller which takes advantage of the properties of the fuzzy PI and PD controllers. The effectiveness of the reduced rule PID fuzzy controller is illustrated with numerical examples