Review of XR technology development in fully mechanized mining faces:From 3 D visualization to digital twin

In recent years,digital technologies,including 3D visualization,virtual reality,augmented reality,digital twin,and Cyber physical systems(CPS),has gradually been deeply integrated with longwall mining,thus de-velop a new intelligent operation mode of longwall mining with the integration of virtual and real.Based on the four el-ements of human,machine,environment and method,this paper analyzes the digital longwall mining technology and its integration process,which is divided into four stages:XR 1.0-unidirectional virtual simulation from physical to virtual,XR 2.0-offline industrial data-driven virtual planning and debugging,XR 3.0-real-time data-driven virtu-al monitoring,XR 4.0-bidirectional data-driven virtual reverse control.Five aspects of each stage,including the con-nection between virtual and real way,data using,characteristics for different objects,support technology and typical application,were analyzed.In the 1.0 stage,3D modeling information and expert knowledge are used to establish the virtual working face,and the simulation operation and training of mining personnel are carried out through human-computer interaction technology.In the 2.0 stage,the actual offline data component parameter scenarios are used for virtual planning and virtual debugging.At the stage 3.0,a digital virtual working face containing virtual moni-toring and prediction functions was established.At the stage 4.0,the physical mining system and the virtual sys-tem have been synchronized,and the optimal strategy of virtual decision-making is used to control the real physical process in real time.Finally,the relationship between the four stages of XR was summarized,and the current prob-lems in technological development,key technologies that need to be overcome,and ways to continue promoting the in-tegration of virtual development and actual development in the next step were discussed.