Methodology to integrate ergonomics information in contextualized digital work instructions

Musculoskeletal disorders (MSDs), often caused by working in non-ergonomic circumstances, are the most important category of work-related diseases. Different methods exist for examining ergonomics through a variety of postural evaluation techniques (e.g. Rapid Entire Body Assessment (REBA)), which are mostly performed through manual survey-based observations. Consequently, measuring ergonomics of operators is time-consuming and happens only sporadically, often after problems occur. Furthermore, as an ergonomist must assign a score to the performed activity, the ergonomics evaluation is subjective. These problems can be resolved by continuous and automated ergonomic load monitoring methods that directly provide feedback to operators. In order to monitor the operator without interfering the task at hand, a vision-based ergonomics monitoring system is developed. Here, ergonomic features (e.g. joint angles) are estimated based on multiple video streams, which are used to calculate an objective ergonomic score using a standard ergonomics evaluation technique. Although cognitive operator support systems (i.e. digital work instructions) for manual assembly environments are widely used, they do typically not include ergonomics information. The goal of the methodology presented in this work is to a) formulate or update digital work instructions, b) provide the operator feedback on its ergonomic soundness via work instructions and c) generate ergonomic risk level reports in an automated way based on the outcomes of the vision-based ergonomics evaluator. Making the ergonomic guidelines context-aware ensures that interventions occur at the right time. The methodology is integrated in a framework for context-aware work instructions and is validated via a proof of concept, based on an actual industrial case. Results show that context-awareness enhances user acceptance and ergonomics of the operator.

Publication year:2022

Accessibility:Open