Digital Model of a Mining Stacker for Material Tracking : Modelling a Mining Stacker with Forward Kinematics for Material Tracking

Abstract: The Fourth Industrial Revolution is reshaping the manufacturing industry with the emergence of interconnectivity, smart automation, and cyber-physical systems. A popular example of cyber-physical systems is the digital twin or digital model, which both create a virtual (cyber) representation of a system. This virtual representation enables the simulation of manufacturing processes and thereby allows facilitating the understanding, optimization, planning, and prediction of the behavior of the manufacturing chain without interfering with the real system. Mining is an energy-intensive industry that can benefit from process optimization, improved production planning, and more precise material quality predictions. To accomplish this, the mined material must be tracked from its source through the mining process chain to its final destination. Because a continuous material flow cannot be tracked in the same way as a manufacturing piece can, a digital twin or model is a suitable solution for material tracking. This project is part of the effort to develop a digital model of the mining process chain and focuses on a specific mining process, the bucket-wheel stacker. A stacker is a huge machine that builds stockpiles with arriving bulk material. The digital model of the stacker must predict the stacker’s behavior in terms of spatial and temporal changes the stacker applies to the material flow. A carrier-portion model is used to digitize the material flow into discrete material portions which are transported by virtual carriers in the digital model. With the help of the forward kinematics method, the digital model utilizes a parameterized robotic model of the stacker to describe the spatial aspect of the stacker. Temporal changes are represented with simple speed-distance-duration calculations. The digital model is implemented in Java programming code and is implemented into an existing material tracking program. The results of the digital model validation show an adequate spatial accuracy of ±0.1 [m] compared to simulated and calculated values. The temporal accuracy is guaranteed to be lower than ±1 [s] compared to calculated values for certain implementation parameters. This project demonstrates that a lightweight digital stacker model for material tracking is feasible and has the potential to be expanded into a digital twin.