New technologies, such as cloud computing, the Internet of Things, wireless communications, etc., have already become part of our daily lives. This paper provides an insight into one of the new technologies, i.e., augmented reality (AR), as part of the manufacturing paradigm Industry 4.0 (I4.0). The aim of this paper is to contribute to the current state in the field of AR by assessing the main areas of the application of AR, the used devices and the tracking methods in support of the digitalization of the industry. Searches via Science Direct, Google Scholar and the Internet in general have resulted in the collection of a large number of papers. The examined works are classified according to several criteria and the most important data resulting from them are presented here. A comprehensive analysis of the literature has indicated the main areas of application of AR in I4.0 and, among these, those that stand out are maintenance, assembly and human robot collaboration. Finally, a roadmap for the application of AR in companies is proposed and the most promising future areas of research are listed.

During pneumatic control system design, the critical value for choosing the appropriate pneumatic actuator is the weight of the workpiece. In the case of flexible production systems, which are the core part of the Industry 4.0 (I4.0) concept, the weight of the workpieces is often variable, since the crucial feature of this kind of production is its ability to deal with variable parts. Therefore, in order to deal with the variable weight of parts, a pneumatic actuator is chosen according to the heaviest part. However, according to another I4.0 principle, energy efficient operation of machines, the previous criteria for choosing a pneumatic actuator is energy efficient only when handling the heaviest part. In all other cases, operation of the pneumatic actuator is suboptimal in terms of energy efficiency. Aiming to solve this problem, this paper considers the possibility of using a new pressure regulator instead of traditional manually adjusted pressure regulators. This regulator provides operating pressure modification in real-time in accordance with the weight of the workpieces. In this way, the optimal compressed air consumption is ensured for each workpiece. Implementation of this device has yielded significant energy savings; however, the value is variable and depends on working task characteristics.

In order to improve the energy efficiency of multi-actuator pneumatic systems, a control scheme for the recovery of exhausted compressed air is designed and studied herein. This paper explains the procedure for the development of the balanced operation of a multi-actuator pneumatic system through the collection and reuse of exhausted compressed air. Compared with traditional motion control of pneumatic actuators, significant energy savings can be achieved, while the dynamic behavior of the cylinders from which the exhausted air is collected is maintained.

This paper presents an experimental setup called pneumatic circular manipulator. The manipulator represents a modular setup that can be adapted to the new situation by simple transformations. It is used for testing various types of pneumatic control and energy efficiency of pneumatic control systems. The manipulator is primarily intended for students and their lectures. Since it has the possibility for remote control over the Internet, due to its modularity, it can be very interesting for researchers and employees in industry. The existing version of the manipulator allows visual monitoring of the working cycle and familiarization with the basics of pneumatic control and motion control for users. By future upgrade, the manipulator will become a setup that will provide feedback on the consumption of compressed air, analysis of the type of control, cost-effectiveness analysis etc.

Over the past decades, the industrial sector has been trying to improve the use of resources and the environmental impact they create. Significant work has been done in compressed air systems. However, there is still much room for improvement. The focus of this study is on a new approach to energy efficient compressed air filtration. This approach involves the installation of different filter configurations that enable a lower pressure drop, instead of the conventionally selected filter. The goal is to reduce the pressure drop, while maintaining the same level of air quality. Pressure drop and compressed air quality are taken as key performance indicators that assess the efficiency and sustainability of compressed air system. It has been experimentally proven that compressed air quality classes remain the same for filters with the same grade of filtration, regardless of the number, type, and way of their installation. However, there is a small difference in the case of particulate and coalescing filters. This environmentally friendlier approach provides a win-win situation. The pressure drop is reduced, costs are also reduced, the system operates continuously and more reliably, and the process is more sustainable.