Use of a rule-based system for process control

A rule-based, digital, closed-loop controller that incorporates fuzzy logic has been designed and implemented for the control of power on the 5-MW Massachusetts Institute of Technology (MIT) Research Reactor under both steady-state and transient conditions. A comparison is made of the rule-based and analytic approaches. Differences in the division of labor between plant engineers and control specialists, the type of knowledge required and its acquisition, the use of performance criteria, and controller testing are discussed. The design, implementation, and calibration of rule-based controllers are reviewed, with specific examples taken from the completed work on the MIT Research Reactor. The possible role of rule-based technology in process control is evaluated. It is proposed that since rule-based systems are generally more robust than their analytic counterparts, they should be used both as backups to analytic controllers and as a means of improving the man-machine interface by providing human operators with the rationale for automatic control actions.<>