Enhancing shipyard transportation efficiency through dynamic scheduling using digital twin technology.

Uncertainties, such as road restrictions at shipyards and the irregular shape of blocks, pose challenges for transporter scheduling. Efficient scheduling of multiple transporters is critical to improving transportation efficiency. The digital twin (DT) technology offers numerous benefits, enabling interactions between the virtual and real worlds, real-time mapping, and dynamic performance evaluation. Based on DT technology, this study proposes a dynamic scheduling approach for cooperative transportation utilizing multiple transporters. The scheduling problem for multiple transporters is addressed and modeled in this study, considering factors such as block size and transporter loading. To solve this problem, a framework of DT-based multiple transporters system is established in a virtual environment. By inputting block information into this system, a solution is generated using transporter scheduling rules and interference detection methods. Experimental comparisons are conducted in this paper, exploring various scenarios with different number of tasks and the application of DT. The results demonstrate that the proposed approach effectively enhances transportation efficiency and improves ship construction efficiency. Hence, this study expands the application of DT technology in dynamic scheduling of transportation in shipyards and provides new ideas for shipbuilding company managers.

Upper limb kinematical analysis of an elite weight lifter in the squat snatch.

The kinematical parameters such as translational acceleration and angular acceleration in the upper limb of a weightlifter may change regularly during different phases of squat snatch. This study aims to make this question clear. At first, the joint coordinate system (JCS) of human upper limb based on the anatomical landmarks is defined. Then a novel method for calculating the kinematical parameters was brought forward, which was based on analyzing the relative position of the JCS to world coordinate system during an instantaneous situation and the relationship among each JCS at different times during squat snatch. Motion capture system is used to gather the data of the upper limb in an elite weightlifter during squat snatch (the mass of the barbell is 20 kg) and the method mentioned before is applied to analyze the data. Finally, the law of the change of kinematical parameters in each phase of squat snatch is found.