The adoption of Digital Twin (DT) solutions for industrial purposes is increasing among small- and medium-sized enterprises and is already being integrated into many large-scale companies. As there is an increasing need for faster production and shortening of the learning curve for new emerging technologies, Virtual Reality (VR) interfaces for enterprise manufacturing DTs seem to be a good solution. Furthermore, with the emergence of Industry 5.0 (I5.0) paradigm, human operators will be increasingly integrated in the systems interfaces though advanced interactions, pervasive sensors, real time tracking and data acquisition. This scenario is especially relevant in collaborative automated systems where the introduction of immersive VR interfaces based on production cell DTs might provide a solution for the integration of the human factors in the modern industrial scenarios. This study presents experimental results of the comparison between users controlling a physical industrial robot system via a traditional teach pendant and a DT leveraging a VR user interface. The study group involves forty subjects including experts in robotics and VR as well as non-experts. An analysis of the data gathered in both the real and the virtual use case scenario is provided. The collected information includes time for performing a task with an industrial robot, stress level evaluation, physical and mental effort, and the human subjects’ perceptions of the physical and simulated robots. Additionally, operator gazes were tracked in the VR environment. In this study, VR interfaces in the DT representation are exploited to gather user centered metrics and validate efficiency and safety standards for modern collaborative industrial systems in I5.0. The goal is to evaluate how the operators perceive and respond to the virtual robot and user interface while interacting with them and detect if any degradation of user experience and task efficiency exists compared to the real robot interfaces. Results demonstrate that the use of DT VR interfaces is comparable to traditional tech pendants for the given task and might be a valuable substitute of physical interfaces. Despite improving the overall task performance and considering the higher stress levels detected while using the DT VR interface, further studies are necessary to provide a clearer validation of both interfaces and user impact assessment methods.

For welding of conventional structural steels semiautomatic technologies (MIG, MAG) are widely used, whereas for welding of Al-alloys and stainless steels the TIG welding method is the most common. The current study concentrates on welding of thin sheet metal products from stainless steel and aluminium by using a novel cold metal transfer (CMT) process. The CMT technology is an alternative to TIG, providing advantages, such as reduction of distortions and increased productivity. This is mainly due to low heat input, achieved by controlled movement of the electrode. In order to realize these advantages, optimization of the CMT welding process is essential. The aim of this study was the optimization of the process using the existing welding equipment (robot, manipulator, etc) and validation of the CMT process. The limiting factors for the increase of the productivity are the reduction of quality (increase of porosity, distortions and inacceptable shape of the welding bed). As a result, practical recommendations are given for the implementation of the CMT technology for robotic welding.

Digital Twin (DT) concept nowadays is shown via the simulations of the manufacturing systems and included those production processes and parametric 3D models of the product. It is the primary method for planning, analysing and optimising the factory layout and processes. Moreover, work on management via the simulation in real-time is already done using Virtual Reality (VR) tools from a safe and remote environment. However, there is a list of limitation of such kind of digital systems, as connectivity speed and precision of the digital environment. The primary goal of this study is to access second listed limitation and on the example of the fully synchronised physical with its digital replica industrial robot, increase the level of precision of the developed DT environment. The proposed approach introduces transfer of the mathematical model to the virtual environment, thus creating a precise and scaled visual model of the Industrial Robot.

Modern Industrial Robot (IR) programming process is mainly performed by using three different methods — manual, offline, and online programming. Each of these methods has various advantages and disadvantages. Prominent automotive industries often use a combination of them, as there is no way to avoid one or another form of programming on one factory. However, the use of a combination of different programming methods is time-consuming and demands the operator’s presence on site for reconfiguration of the IR. The primary goal of this study is to introduce and test the concept of a hybrid IR programming method, which combines both: offline and online robotic cell design, programming, and re-configuration methods. Testing of this method is based on fully synchronized robotic cell’s Digital Twin (DT), developed in Industrial Virtual and Augmented Laboratory of Tallinn University of Technology. Usage of the virtual replica allows to plan and program robotic cell on the means of telepresence and interfere with the predefined path of the robot by online programming method. Moreover, this approach reduces the time for robotic cell design and re-programming, enables to minimize downtime of the robotic cell on the factory shop floor. Included Virtual Reality (VR) environment allows simulating a full-scale operator presence on site. Thus, the proposed approach supports an immersive and safe environment for the IR and similar equipment programming purposes.

During recent years the automation of production processes in small and medium enterprises (SME-s) has been a subject of growing interest. The economy of scale and increased volume of production can be achieved by selecting the right strategy for the automation. The automation systems are as a rule complex and their implementation is resource consuming for SME-s. In the present paper we study implementation of robot welding cells in several enterprises. It is shown that introducing robot welding cells in SME-s is a difficult task because of the limited resources and lack of the needed competence in SME-s. For successful realization of automation projects the complex systems must be divided into smaller and simpler parts using modular approach. The success of the project can be achieved through suitable definition of the modules. This makes it possible to implement the project steps in parallel by involving the needed resources.

From smart factories to service applications, human-robot interaction is crucial to the development of collaborative settings in which humans and robots operate side by side. Since robots in shared spaces must take into consideration variables such as human motion unpredictability and potential workplace risks, effective risk management is essential. When building these systems, striking a balance between factors such as safety, ergonomics, and operational flexibility becomes crucial. Misalignment between human purpose and robot behaviors might result in accidents or increased injury risks, especially in environments with high physical demands. One of the key challenges in human-robot interaction is handling uncertainty. The main aim of the current study is to introduce a conceptual framework for safety/risk analysis, including a hierarchy tree of the risk criteria and risks. Both human- and robot-related factors are considered. The multi-criteria decision-making procedure developed for autonomous vehicle systems is adapted for risk analysis in human-robot interaction. As a final result, the prioritized risk criteria and risks are identified. These results lay the foundation for reducing risks in the future.