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It is generally accepted that all postures obtained from motion capture technology are realistic and accurate. Physical props are used to enable a subject to interact more realistically within a given virtual environment, yet, there is little data or guidance in the literature characterizing the use of such physical props in motion capture studies and how these effect the accuracy of postures captured. This study was designed to evaluate the effects of various levels of physical prop complexity on the motion-capture of a wide variety of automotive assembly tasks. Twenty-three subjects participated in the study, completing twelve common assembly tasks which were mocked up in a lab environment. There were 3 separate conditions of physical props: Crude, Buck, and Real. The Crude condition provided very basic props, or no props at all, while the Buck condition was a more elaborate attempt to provide detailed props. Lastly, the Real condition included real vehicle sections and real parts.

Due to the challenges in quantifying hand loads in manufacturing environments it is often assumed that the load is evenly distributed between the hands, even when handling parts with non-uniform mass distribution. This study estimated hand loads for six female subjects, when handling a custom part in 8 different configurations (2 weights, 4 CofM locations). The calculated hand loads varied from 20 to 50% of the weight being handled. The magnitude of asymmetrical hand loading depended on both the part orientation and the location of the CoM. Based on this study the knowledge of part weight, CofM location and hand positioning will allow the users of digital human models to perform more realistic and reliable task analysis assessments as the force distributions will be more representative of the actual loading rather than simply assuming the load is evenly distributed between the hands.

Henry Ford is credited with the invention of the assembly line and for 100 years now we have manufactured high quality cars and trucks. The process to bring cars and trucks into production has seen many changes with the introduction of new technology, however the principle is still the same; designers draw concept designs and engineers transform these designs into functional parts. The first time the engineering community has a real feel for the design and process compatibility is at a physical prototype build. The money invested in the designs and prototype parts alone make the thought of a design change this late in the game, unbearable. The design of the manufacturing process along with product design has embraced virtual tools and digital human models to assess assembly feasibility. The major incentive to utilizing such tools is to reduce costly re-engineering of parts and to decrease prototype costs. Virtual technology allows ergonomists and engineers to perform “virtual builds”.