Experimental Design for Small-Scale Trials of Upper Limb Exoskeletons in Automotive Assembly Workstations

This thesis deals with the design of small-scale experimental tests for the ergonomic analysis of upper limb exoskeletons in automotive assembly workstations. The study was carried out at the Stellantis plant in Mirafiori, Turin, in collaboration with Homberger SpA and SuitX by Ottobock. The device used for the experimental tests was Ottobock's IX Shoulder Air, designed to support the upper limbs during overhead tasks. The study began with research into the needs that led to the introduction of exoskeletons, a general overview of the current characteristics of exoskeletons on the market, and a general description of the regulatory landscape in use. After describing the device used in detail, the study moved on to an in-depth risk analysis divided into risks due to the design of the exoskeleton, risks related to the working environment, with a particular focus on the specific characteristics of the production line, and risks arising from the implementation of the exoskeleton. After discussing the risk assessment methods adopted, the application of the Ocra Checklist in the case in question was addressed. This is followed by a detailed description of the exoskeleton implementation procedure and the evaluation methods used to interpret the results obtained, divided into subjective feedback from operators and objective parameters obtained through laboratory tests with a the Xsens Awinda system and reprocessing using Scalefit. The results obtained from this experiment show that the device has a clearly positive and beneficial impact on the operator. The laboratory measurements, supported by the calculation of average support values and the comparison of behavior curves as a function of time of the torque acting on the scapulohumeral joint, show a decrease in the torque values acting on the scapulohumeral joint and an improvement in working conditions. However, subjective data suggest that this is not enough, as the emotional sphere, the working environment, the predisposition to change, and the choices of working comfort of each individual operator also influence the user's relationship with the device. This study therefore highlights, above all else, the need for adequate and meticulous personalized training for each individual operator, in order to consider every aspect of the person's physical and mental well-being.