# The Use of Augmented Reality for the Management of Equipment Ageing with a Virtual Sensor
## 5 Conclusions  
The scientific literature and websites of various companies developing AR technologies to support industrial activities do not mention the use of the technology for ageing inspections of critical equipment. Current AR applications are designed for the training of workers. In addition, AR is commonly used in equipment maintenance and repair, which can be through displaying guides and operative instructions concerning assembly/disassembly especially in places that are difficult to access. Based on this evidence, AR use proposed in this work is definitely innovative. The virtual sensor is a useful tool for the inspector as well as for the establishment operator to access information that could be needed on-field during inspections. AR provides information about the condition of parts of the equipment that cannot be captured during a visual inspection. Other advantages are related to the elaboration of ageing-related metrics, and their update and storage. The virtual sensor supports performing these operations for all the equipment included in the establishment. In this work, the system, which was developed in a previous version, was improved to make its GUI more user-friendly. The investigation of the HMI supported the implementation process and allowed the improvement of the usability of the software by making it accessible, even to personnel that are not experts in advanced technologies. Currently, the virtual sensor is designed to inspect very large storage tanks for the management of the integrity of some parts of this type of equipment. In particular, the bottom of the tank is not easy to monitor, as its inspection requires the vessel to be emptied and then cleaned to carry out the thickness measurements. These activities are executed at long time intervals to avoid extended stops and repeated exposure of the inspector to unhealthy environments. The use of this system aims to extend the inspection interval by means of the estimation of the expected conditions. The virtual sensor is a particularly useful tool for the inspector, who can benefit from further information during a safety walk, beyond that captured through a direct observation. In addition, the current experimentation has been carried out in the laboratory. Therefore, to address how the terrain and the weather conditions could affect the accuracy and effectiveness of the use of the technology, it is necessary to test it in a real establishment (future development of the system). By means of the laboratory tests, it has been possible to improve the system and its GUI. However, larger-scale implementation requires further improvements. Using mobile devices suitable for difficult environments (e.g., explosive atmospheres) and the ability to work without using wireless connections are both necessary. There may be problems related to scalability, i.e., related to the framing of very extensive equipment, for which it will be necessary to study appropriate solutions. The use of more recent models of smartphones and smart glasses will improve the performance. However, it becomes necessary to update the part of the software that manages the transfer between the App Desktop and the App Mobile. As far as costs are concerned, a preliminary estimate suggests a total expense that includes the cost of smartphones, smart glasses, and software and its maintenance. There are limitations associated with different types of equipment, mainly related to the geometry and complexity of the systems, where it may be difficult to distinguish one piece of equipment from another. The complexity refers to systems with multiple walls or undulating surfaces or with complex intersections, which causes a crowded view. In addition, the virtual sensor appears especially significant in cases where it is difficult to interrupt system operating to monitor a part of it (as in the case of tank bottoms). Conceptualisation, G.A., R.S., G.F., P.B. and M.F.M. ; methodology, G.A., R.S. and M.F.M. ; software, R.S. ; validation, M.F.M., G.F. and P.B. ; formal analysis, G.A. and R.S.