The disassembly of end-of-life vehicles represents a critical stage in the transition toward a circular economy, as it enables the recovery of critical materials and the reduction of environmental impacts. However, this operation, which is primarily manual, remains a highrisk activity, characterized by vehicle variability, the complexity of assemblies and thus of downstream disassembly, as well as by the constraining postures adopted by operators. These conditions expose workers to high risks of musculoskeletal disorders (MSDs) over the long term if no mitigation measures are implemented. The main objective of this thesis is to develop a digital assistance approach for the disassembly of damaged vehicles, focusing particularly on high-value-added components, such as catalytic converters, selected for their content of strategic metals (rhodium, palladium, platinum). This approach aims to integrate ergonomic, technological, and environmental considerations in order to reconcile worker safety, operational efficiency in the disassembly process (upstream), and environmental sustainability in the recycling phase (downstream).
The methodology is based on a triangulation of empirical and numerical data. Field observations were conducted on a real vehicle (Toyota Yaris, ÉTS) and supplemented with information from technical guides (ARPAC, Gouvernement du Québec, 2015) as well as the video “Cutting Catalytic Converters the Right Way”, available in open access on YouTube. These sources made it possible to characterize disassembly tasks, the associated constraints, and the tools used by operators. A digital modeling process in CATIA V5 was then carried out to reproduce disassembly gestures and postures using anthropometric mannequins representing the 95th-percentile male and 5th-percentile female. This simulation enabled the identification of critical postures, joint angles, and biomechanical amplitudes, providing an objective basis for ergonomic evaluation. The results were analyzed using the RULA, OCRA, and KIM-MHO methods, which revealed high-risk levels for tasks involving static exertion, repetitive flexions, and arm movements above heart level.
In parallel, a morphological analysis of the catalytic converter’s ceramic substrate was conducted to identify potential contamination sources, including vibrations during cutting, thermal conduction from tools, and metal fume emissions. These findings, combined with conceptual models from the literature such as those of Pokorni et al. (2022), Fiasche et al. (2016), and Valdesse Eko’Ola and Nadeau (2025), led to the proposal of ergonomic design solutions. Among these, the manual tube cutter mounted on a fixed support significantly reduces constraining postures and risks of substrate damage (Fiasche et al., 2016). The Pokorni et al. (2022) model served to validate the integration of augmented reality (AR) glasses into the disassembly process, while the Valdesse Eko’Ola and Nadeau (2025) model, through a multi-criteria analysis, enabled the selection of the most suitable AR glasses, namely the Magic Leap 2, offering an optimal balance between cognitive assistance, user comfort, and ergonomic performance. Finally, a life cycle assessment (LCA) conducted using SimaPro 9.6.0.1, based on the TRACI 2.1 (Canada 2005) method and the Ecoinvent 3.9.1 database, compared the hydrometallurgical and pyrometallurgical pathways applied to catalytic converter recycling. The results reveal a generally higher environmental footprint for hydrometallurgy across most impact categories (climate change, toxicity, acidification, eutrophication etc.), due to its high consumption of chemical agents (HCl, NaOH) and energy. Although pyrometallurgy is more thermally energy-intensive, it shows lower impacts, notably due to the Canadian and Quebec energy mix dominated by hydroelectricity, whose low greenhouse gas emissions significantly mitigate energy-related impacts. These findings demonstrate that LCA analyses must be regionalized to account for specific energy and industrial contexts, ensuring a more accurate and context-relevant evaluation of the environmental performance of recycling processes.
| Date | 7 May 2026 |
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| Original language | French |
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| Awarding Institution | - École de technologie supérieure
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| Supervisor | Sylvie Nadeau (Supervisor) & Lucas Hof (Co-supervisor) |
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