Développement et analyse d’une méthode d’assemblage par projection des instructions

Abstract

In recent years, the use of digital assistance devices over manual methods for product assembly has gained importance in various industries such as aerospace, construction, and agri-food, promising improved productivity and ergonomic benefits for workers. This thesis presents an in-depth comparative study on the implementation of two methods during assembly: one using the assistance of a FARO® projector and the other, a manual method based on dimensional measurements provided on a technical drawing. The objective is to compare the performance of the two methods, assess their usability, evaluate their impact on performance (assembly time and quality criteria), and analyze participants’ experiences during the assembly process. This study involves assembling three spatial configurations composed of parts with different geometries. The parameters collected include assembly quality (compliance with required tolerances, inspected using a measuring arm), assembly time, and participants’ postures captured with GO-PRO® cameras. Finally, participants’ perceived workload (mental and physical) was evaluated using the NASA-TLX (NASA Task Load Index). Statistical analyses using ANOVA on the experimental results indicate that the FARO® projection-assisted method is significantly more accurate than the manual method. The accuracy data is measured using the HEXAGON® measuring arm. Moreover, a remarkable 75% reduction in assembly time was observed when using the projection-assisted method compared to the manual method. The absence of measurement tasks is one of the key factors explaining this outcome. The NASA-TLX results also indicate a reduction in participants' mental workload when using the FARO® method, thanks to the projected instructions and real-time visual guidance. While the projection method indeed offers greater precision than the manual method, certain geometric shapes with difficult-to-project outlines may lead to errors (human or precisionrelated) during assembly. Additionally, the assembly table used is designed for standing work. However, since it offers no adjustability, it cannot ensure a comfortable ergonomic posture for 90 to 95% of the North American participant population. As a result, several ergonomic risks— such as trunk flexion and significant strain on the unsupported shoulder girdle during precision work—can negatively affect assembly accuracy and overall performance. Therefore, using a height-adjustable table would be advisable. These findings could serve as a basis for future work aimed at identifying which parts are best suited for the FARO® projection-assisted method.

Date	17 Nov 2025
Original language	French
Awarding Institution	École de technologie supérieure
Supervisor	Sylvie Nadeau (Supervisor) & Antoine Tahan (Co-supervisor)