UBC Theses and Dissertations
A qualitative modeling facility for intelligent supervisory control systems (ISCSs) Cifuentes, Edgardo Ivan
Control strategies based on purely mathematical algorithms have only limited ability to cope with the type of operating conditions found in full-scale industrial applications. One approach to overcome this limitation integrates elements of automatic control theory, artificial intelligence and operations research into the design of a control system. This approach is employed in this research study to design an intelligent supervisory control system (ISCS). Elements of artificial intelligence to provide “human-like” characteristics for the ISCS are central to this research. Pseudo-Qualitative Modeling as a central component of an ISCS is proposed in this research. This approach provides the mechanisms required by the ISCS to handle heuristic knowledge and approximate reasoning required in many supervisory control applications. A simulation study has been performed to demonstrate the validity of this approach. Simulation results have shown that this technique can handle either poorly-defined heuristic models or accurate models based on mathematical concepts. In fact, pseudo-qualitative modeling provides a framework to integrate qualitative and numerical models into a knowledge-based system. A prototype of an ISCS was implemented using ProcessVision, a real-time SCADA (Supervisory Control And Data Acquisition) software package. This prototype system was applied to the C-line grinding circuit at Highland Valley Copper (HVC) to monitor and detect tonnage restrictions that affect circuit production. The diagnosis of tonnage restriction is currently performed manually by metallurgists on a weekly basis. This method is a heuristic procedure based on highly subjective judgment. The diagnosis results provided by the ISCS prototype during the evaluation period were well within the range of those reported by HVC metallurgists. Implementation of this ISCS prototype has demonstrated the feasibility of incorporating qualitative modeling into a commercial real-time SCADA system widely used in industrial applications.