Embedded Digital Twin for ARTI-Type Control of Semi-continuous Production Processes

The paper defines the structure and utilisation mode of an embedded aggregate digital twin for the hybrid supervised control of semi-continuous production process. Multiple twin aggregations are defined for the production of radiopharmaceuticals: (i) virtual twins of three main sub processes in the production plant; (ii) predictive and decision making twins and their projections in the supervisor for process resilience and global optimization. The control system is organized according to the holonic reference architecture ARTI that enables the concepts of embedded and networked digital twins that provide collective and predictive situation awareness thus bringing closer the software control to the real process evolution. The research reported in this paper demonstrates that the holonic paradigm, first applied to discrete manufacturing process control, can be adapted to the hybrid supervised planning and control of semi-continuous production processes and brings the benefits that holonic organisations provide to living organisms: direct connectivity between physical plant entities (resources, activities and outcomes) and their virtual twins, global optimization, robustness, process resilience and plant sustainability.