Digital twins are complex virtual representations of physical systems that are linked to a corresponding physical system via sensors and other Internet of Things (IoT) devices. The main complexity lies within both the sensors for environment realization and accurate functional representation of the physical system in a meaningful virtual representation, usually for advanced control and simulation. Digital twin technology has seen vast growth in the last decade, aiming to support solutions for exerting control on physical complex systems. It is a natural evolution and fusion of various emerging technologies such as IoT, wireless networks, sensor integration, machine learning, artificial intelligence, big data and data visualization in the essence of virtual and augmented reality. Undoubtedly, it is one of the pillars of industry 4.0 towards achieving holistic control and communication between labor, machines, and management.

Digital twins can be understood as a representation of a fabrication process or service in the digital world, governed by specific properties and conditions. Therefore, real-world processes and items along with their surrounding environment can be digitally transferred and described in a cyber-world context. In this way, a digital twin can be utilized to analyze and further understand an item or process, leading to its optimization without spending the resources required in a real-world trial and error modus operandi.

This Special Issue will examine the applications and implementation of digital twin technology across various sectors. Authors are invited to submit high-quality original research that includes sensors used in digital twin systems. We also welcome review articles.

Potential topics include but are not limited to the following:

• Digital twin sensors
• Digital twins of new fabrication systems such as 3D printers
• Digital twins of production lines
• Advancements in complex virtual representations
• Virtual and augmented reality (VR/AR) and digital twins
• Complex simulations and digital twins
• New complex algorithms and models for digital twins
• New applications and tools for digital twins
• Digital twins of unmanned vehicles and their applications
• Graphical representations of digital twins
• Computer games and digital twins
• New hardware controllers and digital twins
• Complex feedback systems for digital twins
• Complex system architectures for digital twins
• Smart grids, smart cities, IoT systems and digital twins