# AR-Assisted Guidance for Assembly and Maintenance of Avionics Equipment
## 5 Discussion  
In this paper, the AR-assisted guided visual assembly and maintenance method for avionics equipment was studied. We first proposed an assembly object pose tracking method based on RGBD data. The assembly guidance information can be superimposed on a real object based on obtained pose data. And our method can reduce the user's interaction pressure through assembly step identification and improve the usability and operation efficiency. Different from the existing AR guidance manual methods [45; 46; 47], our method enables the overlay of AR instructional information on both static and dynamic components. Experimental results show that our method is particularly well-suited for assembly and maintenance tasks with visual blind areas. Then, we proposed the AR visual assistant guidance method for blind areas in assembly and conducted experiments with the traditional guidance method for training, assembly, and maintenance tasks in the avionics equipment scene. We collected statistical data and analyzed four aspects of the three tasks: completion time, learnability, usability, and mental effort. The results show that the AR guidance method is significantly better than the traditional guidance method in terms of completion time, learnability, and usability evaluation and that the ARG has a lower mental workload. In terms of learnability, the ARG group significantly outperformed the TG group in both Task 1 completion time and SUS learnability scores. This was because the ARG group used AR glasses, in which 3D model assembly animations and voice explanations could help the participants intuitively understand the assembly parts, processes, tools and other information and quickly achieved the purpose of enabling participants to build with confidence and think that they could complete the assembly task well and quickly. However, the participants in the TG group needed to understand the content and technical requirements of the assembly order according to two-dimensional drawings. The understanding abilities of participants with different skills are different, which is the reason why the TG group in Task 1 not only took a long time but also had a large SD. In terms of usability, ARG has higher usability than TG. The main reason for this difference is that, in Tasks 2 and 3, the AR guidance method could guide the operator to complete the AO or MOP step-by-step. The operator did not need to think, only to concentrate on completing the corresponding operation according to the instructions of the system. In contrast, the traditional guidance method relies on 2D paper drawings and process manuals, resulting in workers' attention switching back and forth between the assembly object and the manual. And the continuous shifting of operators' attention leads to an increase in their mental effort. As a result, the completion time increases and the operation efficiency decreases. In addition to that, some participants in the TG group (U\({}_{\rm TG}\)1, U\({}_{\rm TG}\)3, U\({}_{\rm TG}\)5, and U\({}_{\rm TG}\)13) reported that for bolt assembly in narrow spaces, it was difficult to find the bolt hole and align the hexagon bolt sleeve at the end of the extension rod with the bolt. However, the participants in the ARG group did not report such problems. Onthe contrary, some of them mentioned the convenience of perspective presentation in the interview (UARC3, UARC4, UARC7, UARC10, UARC12, and UARC13). The main reason is that the AR guidance method has obvious advantages in visual guidance with respect to blind areas in assembly and maintenance work and can achieve a perspective-like effect. In the task, it helped the operator to better understand the assembly object and the position of the bolt hole in the narrow space. Moreover, it reduces the occurrence of mis-assembly caused by occlusion and effectively improves assembly efficiency and quality. In terms of mental effort, the experimental results show that the participants in the ARG group put in less mental effort than those in the TG group.