# A Digital Twin System for Adaptive Aligning of Large Cylindrical Components
## 2 DT Aligning System for Cylindrical Components
### Overall Design of the DT Aligning System  
The overall design framework of the DT aligning system is constructed based on the DT modeling method referred in Ref. [21], which integrates physical space, virtual space, and twin data through correlation and fusion, enabling information exchange and virtual-to-physical mapping during the aligning process of the large component. When the performance requirements of the target product are met, the adaptive and optimal operating state of the aligning system is achieved through collaborative control and iterative optimization, as shown in Figure 4.  
**Physical space:** it is the hardware part of the DT aligning system, which is mainly composed of the physical execution system, process sensing system, and the control system. Herein, the dynamic and static platforms, motion control systems, and programmable logic controllers make decisions for aligning tasks and obtain various process data through transmission protocols or multiple sensors to perceive and monitor the aligning status information of large cylindrical components in real time and upload the collected data to virtual space through the network module.  
**Virtual space:** it is the software part of the DT aligning system, which contains the design and modeling modular, and the intelligent decision-making module. The design modeling module maps the properties of physical space devices to virtual space through geometric modeling, physical modeling, data modeling, and functional modeling to construct a twin model of the aligning system. The intelligent decision-making module realizes the consistency between the aligning system in the virtual space and the physical space. The twin model can be continuously improved and optimized through the intelligent decision-making analysis of the algorithm library, and the pre-designed aligning process scheme can be inputted into the intelligent decision-making modular, the aligning program of large cylindrical components can be called, and the interference collision simulation of the aligning trajectory can be carried out to ensure the feasibility of the aligning process  
Figure 4: Overall design framework of the DT aligning system.  
scheme. In addition, during the aligning process execution, aligning system calibration, multi-source data processing and fusion, and feedback control can be used to adjust or optimize the aligning process, in order to achieve the closed-loop adaptive aligning of large cylindrical components.  
**Twin data:** there are a large amount of multi-source real-time data in the aligning system. Twin data, as the foundation of the DT aligning system, supports the operation of physical and virtual spaces and is also used for system modeling, feature extraction, and the optimization of decision-making. Data collection, transmission, and storage technologies are crucial for the accuracy and real-time perception of the aligning system information and can achieve the real-time performance monitoring of static and dynamic platforms and the aligning status of large components during the aligning process.  
Thus, physical space, virtual space, and twin data combine to form the adaptive aligning system of large cylindrical components, allowing for the high-quality and efficient aligning assembly of large components.