Keeping digital twin in sync without blocking the physical motion stage

Digital Twins (DTs) are virtual representations of physical systems or Physical Twins (PTs) that are used for various data-driven applications in manufacturing industry such as predictive maintenance, diagnostics and condition monitoring. In high-throughput production systems such as semiconductor manufacturing equipment, the motion of the equipment is controlled by high-speed high-precision motion stages. The use of digital twins in such systems is limited due to real-time requirements of these systems. Data in DTs is collected through virtual sensors. Virtual sensors augment the capabilities of the physical sensors by providing additional data that is not directly observable by physical sensors. In order to enable real-time applications, the DT must be synchronized with its physical counterpart to ensure timeliness of data from virtual sensors. The synchronization mechanism should be non- blocking ensuring that the throughput of the physical systems is not affected. In this paper, we propose a synchronization mechanism for DTs in high-speed high-precision motion control systems. The mechanism involves sharing PT states with DT over a network and compensating for network delays. The synchronization mechanism is validated in a framework comprising an industrial motion stage system and its digital twin. The validation is done for different synchronization delay scenarios, demonstrating its effectiveness of proposed approach in eliminating synchronization delays without blocking the PT operation. The proposed mechanism enables real-time virtual sensing ensuring data timeliness with high accuracy.