Using motion capture to study human standing accessibility: comparison between physical experiment, static model and virtual ergonomic evaluations

Computer-aided modeling softwares are tools commonly used to perform ergonomic analyses, and specifically to assess the accessibility of products and environments. These tools are used to represent the dimensional characteristics of the end user in 3D and in a virtual environment. However, it remains often difficult to model the behaviors and capabilities of the subjects, which may influence the ergonomic analyzes. In this paper, a methodology using a motion capture device is presented, which integrates the human behavior and the physical characteristics of the body during the design evaluation process. The limits of validity of this approach are assessed by comparing the reach envelopes obtained by this method to those obtained through a static model, a CAD evaluation and real experiment with a panel of subjects. First, the accessibility areas of forty adult subjects, which may correspond to the distance of reachability of products, were evaluated by performing an accessibility task comprising 168 reach points. Second, anthropometric characteristics of participants were recorded and used to perform the reach assessments by a static approach, and then by a CAD-based analysis, where the reach was predicted using the software’s maximum reach envelope generation. Finally, anthropometric characteristics were used to define virtual mannequins, controlled by the designer and a motion capture device in order to perform the accessibility assessments. In spite of the simple nature of the presented design problem (two-dimensional), the results show important differences between the methods. The proposed methodology using a motion capture provides the most similar results to those obtained from the experiment.