Digital Twin in Industry 4.0: Technologies, Applications and Challenges The digital transformation that is ongoing worldwide, and triggered by the Industry 4.0 initiative, has brought to the surface new concepts and emergent technologies. One of these new concepts is the Digital Twin, which recently started gaining momentum, and is related to creating a virtual copy of the physical system, providing a connection between the real and virtual systems to collect and analyze and simulate data in the virtual model to improve the performance of the real system. The benefits of using the digital twin approach is attracting significant attention and interest from research and industry communities in the last few years, and its importance will increase in the upcoming years. Having this in mind, this paper surveys and discusses the digital twin concept in the context of the 4th industrial revolution, particularly focusing the concept and functionalities, the associated technologies, the industrial applications and the research challenges. The applicability of the digital concept is illustrated by the virtualisation of an UR3 collaborative robot which used the VREP simulation environment and the Modbus communication protocol.

Concept and Implementation of a CyberPbysical Digital Twin for a SMT Line This paper conducted research on the concept design and implementation of a cyberphysical digital twin system for manufacturing. Based on literature reviews and industry requirements for a cyberphysical digital twin system for manufacturing, this paper proposed a concept design architecture of a cyberphysical digital twin system and its implementation methodology. An application of building a cyberphysical digital twin system for a SurfaceMountedTechnology (SMT) line is illustrated based on the proposed concept and framework. The basic requirements of the proposed cyberphysical digital twin system are divided into three layers, i.e. operations layer, visualization layer, and intelligence layer. Operations layer is about systems modeling of the physical processes and establishing connections with the cyberspace. Visualization layer is related to the collection and displaying of the historical and present data in a visual manner. The intelligence layer is the ability to conduct data analytics and decision makings to identify patterns and bottlenecks, reduce waste, perform predictive maintenance, etc. A proof of the concept prototype is developed based on the proposed cyberphysical digital twin system for a SMT line.