# WARM: Wearable AR and Tablet-Based Assistant Systems for Bus Maintenance
## 6 Conclusions  
The result of this work has been the development of two solutions for improving the maintenance of bus fleets: one based on Android-based tablet and another one based on Microsoft HoloLens AR headset. The developed solutions are designed as a front-end for interaction with the GIM system. This development is a simplified application of Android GIM that helps fill in the maintenance sheets. This application connects directly through Web Services to the database server. As a summary of the AR task, different tracking methods (spatial mapping and object detection) have been used to analyze the environment and locate the user respected to the environment itself and the bus. Once the bus is detected and located, it has been possible to include virtual objects in it. The two solutions have been tested in real operation condition against the current paper-based procedure. Tests have taken place in the garage at the premises of DBUS, which operates the public transport buses in the city of San Sebastian (Spain). Experimental results prove the superior performance of the tablet-based solution in terms of reduction of effort for data management and processing and staff's perception of workload. Other conclusions are that workers are ready to adopt these tools (tablet-based solutions) that make their work easier. Regarding the additional information collected (videos, photos, etc. ), it has been well received by the workshop manager verifying that the multimedia data enriches the information system. Finally, the analysis of the relative improvement of the proven innovations, presented in Table 4, suggests that the tablet-based maintenance assistance system is worth retaining and therefore seems suitable for further developments to achieve TRL 9. Taking into account the results and the company feedback, as for a quick and comfortable implementation for operators, future steps will be made towards the implementation of kiosks, instead of tablets. Workers have shown good acceptance of this type of device because it leaves them hands free and they do not need much more to carry out their daily work. As for further research in AR, future lines should go towards more comfortable devices (it depends on the market) and GUIs that really give real benefits to the user in the form of more functionalities and/or user experience than tablet-based solutions. Conceptualization, D.B. and A.S.; methodology, D.B. and A.S.; software, J.M.G. and E.O. ; validation, J.M.G. and E.G. ; investigation, D.B., A.B., A.S., J.M.G., and E.O. ; resources, D.B., A.B. and A.S.; writing--original draft preparation, D.B. ; writing--review and editing, D.B., A.B. and A.S.; supervision, D.B., A.B. and A.S.; project administration, D.B., A.B. and A.S.; funding acquisition, D.B. and A.S. All authors have read and agreed to the published version of the manuscript. This research was funded by the European Commission in the frame of EBSF 2 project (\"European Bus System for the Future 2\", grant number 636300) and by Economy and Competitiveness Ministry, RETOS-COLABORACION program, in the frame of MANBUS project (\"System for assistance Bus Maintenance\", grant number RTC-2015-3419-4). \begin{table}
\begin{tabular}{c c c c} \hline \hline
**KPI** & **Target** & **Tablet vs. Paper** & **AR H. vs. Paper** \\ \hline
1.a—Effort for data management & 10\% & 54.5\% & \(-\)116.9\% \\
2.a—Efforts for data processing & 25\% & 29.1\% & 29.1\% \\
2.b—Staff’s perception of workload & 10\% & 8.8\% & \(-\)7.0\% \\
3.a—Maintenance staff cost per vehicle & 10\% & 0.3\% & \(-\)1.3\% \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Final assessment: relative improvements (in %). Negative values correspond to worse values than those obtained with the current procedure (Paper).