The minimal AR authoring approach: Validation in a real assembly scenario

This work aims to validate the “minimal AR” authoring approach in a real industrial assembly scenario. It focuses on optimizing visual assets in Augmented Reality (AR) work instructions. The design of AR assembly documentation is influenced by three main variables: work instructions, affordance (dependent on equipment components and operator capabilities), and AR signifiers (combination of visual assets with their properties). In this study, we fixed the instruction complexity while exploring the relationship between affordance and AR signifiers. First, we set up a focus group of 10 experts in AR technical documentation to extract guidelines for the design of minimal AR signifiers for assembly instructions with a variable affordance. Then, we validated these guidelines through an industrial case study involving 34 participants in four assembly tasks. We verified if the candidate minimal AR signifier, obtained using the proposed guidelines, corresponded to the minimal AR signifier established by users. The results showed that in 33% of the cases, users exploited the candidate minimal AR signifier to accomplish the task successfully. Beyond the minimal AR signifier, an additional one conveying the notification about the task success must always be provided to ensure failure by those operators with reduced capabilities. We also found that, in 29% of the cases, users needed less information than the candidate minimal AR signifier due to their higher capabilities. However, as expected, this condition leads users to make more errors than with the candidate minimal AR signifier. Moreover, the study confirms that AR signifiers with redundant information or attractive appearance, such as animated product models, are unnecessary to improve task comprehension. Still, animations could be beneficial in reinforcing understanding when object properties are difficult to detect.