Ergonomics Characterization in Digital Manufacturing: A new Ergonomic Index Proposal

Ergonomics can be employed in refining manufacturing tasks, tools handiness and workplace assessment. An ergonomic study is able to increase worker safety (preventing and avoiding hazards within working environment) and eliminate awkward positions and useless actions. These reflect on worker productivity and motivation, reduction of absenteeism (for diseases), increase of attention on core tasks and finally improving of product quality. Therefore, the principal objective of an ergonomic study and procedure optimization is to reduce, or possibly avoid, those bad postures that cause stresses and/or physical disorders (which generally affect upper and lower limbs). Many observational, epidemiological and anthropometrical studies have been conducted to assess these disorders. On the other hand, these models often employ qualitative and too much subjective parameter. They focus on particular and very specific aspects regarding the posture. Hence, traditional models cannot be considered as standalone approach for a complete ergonomic analysis of working tasks. The present investigation has aimed at highlighting the limits of the traditional methods, the presence of overlaps and field of applicability. Furthermore, the analysis and joining of the advantages of the principal ergonomics indexes have driven to develop a new synthetic index (ViRWL) which surpasses the actual models limitations. The relative simplicity of such a model (which calculates the stresses on the limbs, the maximum allowable load with the absence of subjective and uncertain parameters contribute) has allowed the developing of a completely automatic routine which can be easily introduced in digital ergonomic environments