AN ERGONOMIC QUANTIFICATION CONCEPT FOR WRIST MOVEMENTS IN DHM-ENVIRONMENTS

Abstract: The increasing level of computerization in design and engineering work has led to development of software such as Digital Human Modeling (DHM) Tools. These tools are used to simulate and visualize human work as well as evaluating ergonomic conditions. The ergonomic assessment methods based on observations, such as OWAS and RULA, are used for characterizing static load and are usually integrated in DHM tools. Researchers now aims at developing assessment methods of dynamic work where even time-dependent variables are taken into account. The purpose of this thesis is to develop a concept for quantification of wrist movements in flexion and extension, based on three exposure variables; angular position, angular velocity and repetitiveness. The concept is intended to form the basis for further development of a comprehensive assessment method for wrist movements, adapted for use in DHM tools. Such an approach is necessary because of the large amount of work-related cumulative disorders, reported from industry. The method approach contained a literature review, an establishment of concept content, a collection of motion data using goniometry and computer programming, in order to illustrate the function of the concept. The result proposed a quantification concept for wrist movements in flexion and extension, concerning angular position exposure, angular velocity level exposure and repetitiveness. The concept is based on a combination of modified and established evaluation methods, including suggestions for how to identify fundamental cycles, in order to determine repetitiveness. The presented concept provides a basis for further development of a comprehensive assessment method and highlights deficiencies in the lack of existing definitions concerning exposure threshold values.