Digital Twin-Based Production-Logistics Synchronization System for Satellite Mass Assembly Shop-Floor

In recent years, the rapid development of large-scale satellite constellations has challenged the mass production capabilities of satellite manufacturers. Assembly is the last and critical phase of satellite production. Achieving satellite mass assembly is the key to realizing satellite mass production. To this end, satellite manufacturers are working to construct the satellite mass assembly shop-floor (SMAS) to enable moving assembly. However, there is still a lack of a modularized manufacturing system oriented to flexible production for SMAS, as well as disturbance detection methods and production-logistics synchronization methods to deal with various disturbances. Therefore, this paper proposes a digital twin-based production-logistics synchronization system (DT-PLSS) for SMAS. The framework of DT-PLSS is introduced first. In this framework, DT-PLSS can achieve modular construction, as well as distributed management and control. Based on the proposed framework, the construction methods of resource level digital twin (DT), workstation level DT, and shop-floor level DT in SMAS are discussed. The DT-based disturbance detection method for SMAS is presented, aiming to detect or predict different types of disturbances and to analyze the effect of disturbances. Then, a DT enhanced production-logistics synchronization mechanism for SMAS is proposed. With this mechanism, the logistics distribution in the dynamic shop-floor environment and production-logistics synchronization under various disturbances can be realized. Finally, a case study in a real SMAS verifies the feasibility and effectiveness of the proposed system and methods. This research proposes a practical framework and system which could realize disturbance detection, logistics distribution, and the production-logistics synchronization in complex SMAS scenario effectively.