A spatiotemporal evolution modeling method for flowing entities within production processes in digital twin shop floors

Digital twin (DT) shop floors require effective representation of flowing entities such as workpieces, carriers, parts, and tools to capture production dynamics and support efficient production organization. However, existing research lacks unified modeling of diverse flowing entities and their dynamic evolution, limiting consistent support for various production processes and DT applications such as production execution and simulation. Building upon the previously proposed seven-element modeling theory, this paper proposes a spatiotemporal evolution modeling method based on spatiotemporal-characterized flowing entity model (STFEM) and spatiotemporal dynamic connectivity map (STDCM). STFEM achieves unified representation of various flowing entities and their coupling relationships by extending three dimensions: service relationship, hierarchy, and temporal sequence. STDCM captures the spatiotemporal evolution through dynamic integration of logical flow and structural changes of STFEM. Additionally, production execution and simulation methods based on STDCM are developed to enable consistent DT application integration. Case validation in an actual manufacturing shop floor verifies the method's effectiveness in unified modeling of spatiotemporal evolution for flowing entities and consistent support for production execution and simulation.