_Applied_  
_sciences_  
Creating Collaborative Augmented Reality Experiences for Industry 4.0 Training and Assistance Applications: Performance Evaluation in the Shipyard of the Future +  
Footnote †: margin: [[https://www.mdpi.com/journal/applsci](https://www.mdpi.com/journal/applsci)]([https://www.mdpi.com/journal/applsci](https://www.mdpi.com/journal/applsci))  
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Footnote 1: [[https://www.mdpi.com/journal/applsci](https://www.mdpi.com/journal/applsci)]([https://www.mdpi.com/journal/applsci](https://www.mdpi.com/journal/applsci))  
Received: 14 November 2020; Accepted: 14 December 2020; Published: 18 December 2020  
Featured Application: The proposed collaborative Industrial Augmented Reality (IAR) framework enables creating IAR experiences easily to facilitate, support, and optimize production and assembly tasks through training and assistance. The performance of such a framework is evaluated in terms of packet communications delay, communication interference, and anchor transmission latency. The proposed system is validated in a shipyard, thus providing useful insights and guidelines for future developers of Industry 4.0 applications.  
Industrial Augmented Reality (IAR) is one of the key technologies pointed out by the Industry 4.0 paradigm as a tool for improving industrial processes and for maximizing worker efficiency. Training and assistance are two of the most popular IAR-enabled applications, since they may significantly facilitate, support, and optimize production and assembly tasks in industrial environments. This article presents an IAR collaborative application developed jointly by Navantia, one of the biggest European shipbuilders, and the University of A Coruna (Spain). The analysis, design, and implementation of such an IAR application are described thoroughly so as to enable future developers to create similar IAR applications. The IAR application is based on the Microsoft HoloLens smart glasses and is able to assist and to guide shipyard operators during their training and in assembly tasks. The proposed IAR application embeds a novel collaborative protocol that allows operators to visualize and interact in a synchronized way with the same virtual content. Thus, all operators that share an IAR experience see each virtual object positioned at the same physical spot and in the same state. The collaborative application is first evaluated and optimized in terms of packet communications delay and anchor transmission latency, and then, its validation in a shipyard workshop by Navantia's operators is presented. The performance results show fast response times for regular packets (less than 5 ms), low interference rates in the 5 GHz band, and an anchor transmission latency of up to 30 s. Regarding the validation tests, they allow for obtaining useful insights and feedback from the industrial operators, as well as clear guidelines that will help future developers to face the challenges that will arise when creating the next generation of IAR applications.  
**Keywords:** Industry 4.0; augmented reality; industrial augmented reality; assistance; training; collaborative applications; Microsoft HoloLens