Design of a rule-based continuous process controller using modified IDEF0 methodology

Abstract

This article proposes a new method to design a rule-based Continuous Process (CP) controller. This approach adopts Modified IDEF0 (MI) diagrams as a graphical representation of production rules. Initially, the material flows or functional requirements for the CP are specified by synthesizing the MI diagram primitives. The control flows for the CP are then created by a number of transformation rules. The MI diagrams are therefore transformed to the Final MI (FMI) diagrams which can be directly transformed to production rules. The fact that production rules are created by systematical transformation eliminates any redundant, contradictory, or unnecessary rules. The simulation approach can verify the consistency of the designed CP controller. Thus, a feasible rule-based CP controller can be systematically developed. An illustrative gas transmission system is examined with three manufacturing policies, i.e. Proportional plus Integral plus Derivative (PID) control, Neural control and Fuzzy control. The results indicate that all of these policies are feasible in applying the proposed method. This method not only provides graphical representations to construct well-organized production rules, but also includes a systematical transformation of the control flows for a CP controller.