A Simple Multibody 2d-model for Early Postural Checks in Workplace Design

Posture prediction is one of the most important aspects of virtual modeling tools used for the workplace design: once the work point to reach is defined, the posture prediction module allows simulating, through inverse kinematics, the posture the operator is likely to assume. The paper presents a simple multibody 2D-model created for early postural checks in the design phase. The tool is a spreadsheet created in Microsoft Excel environment, with the support of Visual Basic. The principal output of the model in terms of angles of trunk bending and upper arm elevation, set in compliance with the technical standards, are compared to the results of an established software tool for ergonomic analyses, the 3D Static Strength Prediction Program (3DSSPP). Finally, possible differences in terms of moments on the L5/S1 and the shoulder joints introduced by the simplified kinematics of the 2D manikin are discussed.