A comprehensive digital twin for BEV manufacturing: an ergonomic analysis of the high-tension cable underbody assembly.

The core of the thesis is the integration of two software programs to enhance the simulation of the manual assembly of the high-tension cable on the underbody of a battery electric vehicle. The simulated activity involves working underbody, slightly deviating from the actual workstation design, as the thesis project aimed at highlighting all potential ergonomic issues involved in the manual activity also with reference to the operator's stature. The two companies involved in the project shared a common goal: the search for a tool capable to integrate different features and create the digital twin of the working station. This work exploited the software tools provided by fleXstructures to simulate in the most realistic way the industrial case study assigned by Stellantis. The thesis is made of five chapters: in each of them a different topic and analysis is presented, to guide towards the conclusion and the further developments that could derive from this work. The first part is made of two chapters and is based on a research and bibliographic work: the project background is analysed in terms of how it fits in a wider industrial environment. An overview of the digital twin definition and application is presented, along with the introduction of the tools used to create the one for this work. Then, in the second chapter, the anthropometry topic, and its centricity for a correct ergonomic analysis are described, with a specific attention to the databases used and their correlated methodologies. In the second part of the work, the heart of the project is described. Starting with the third chapter in which the simulation setup and initial hypothesis are presented, the cable simulation and the subsequent presence integration with the manikins has been done. The integration methodology has been described, with its potentialities and limits. In the fourth chapter, the ergonomic analysis is performed by means of the EAWS. This holistic assessment tool is used with the digital simulation and with a manual analysis, to be able to compare the outputs. In the end, a deeper criticality arose. In fact, the different approaches between the digital one, based on a bio-mechanical model, and the manual one, based on pre-determined times, lead to a further analysis investigating the best methodology to assess the level of risk of a manual activity in an industrial environment. The last chapter is dedicated to the conclusion: the whole working activity is summarised, the results presented, along with further potential developments.