Empowering operators with a human-in-the-loop/on-the-loop simulation-based digital twin: the case of a smart learning factory

Industry 5.0 has shifted the focus towards empowering humans and human-technology integration within industrial systems. Interactive Decision Support Systems (DSS) are a key tool for improving overall performance. This paper presents the prototype of a simulation-based digital twin as a support of a DSS that implements both Human-in-the-Loop (HITL) and Human-on-the-Loop (HOTL) approaches. An interactive human-machine interface, interconnected with a self-configurable simulation, assists frontline workers in comprehending a production system characterized by high variability, uncertainty, complexity, and ambiguity. By enabling frontline workers to run simulation models directly from the shop floor, the system empowers them to work alongside machines (in-the-loop) and make informed decisions in real-time, adapting to changing conditions and optimizing processes (on-the-loop). The Analytic Hierarchy Process (AHP) methodology allows to evaluate the adoption of the combined Human-in/-on-the-loop approach over the HITL, based on the complexity of the activity to be executed. A use case is developed at an Industry X.0 Learning Lab at the University of Calabria.