Application of PERA method to analyze and redesign the cyclic tasks in an automotive industry

  Postural Ergonomics Risk Assessment (PERA) is an ergonomic assessment method to detect the major causes of the cyclic work by focusing on the stressful postures analysis in the form of a task analysis. Because of its ability to detect the ergonomic risk sources in work cycles, this study aims to use this method as a systematic ergonomic analysis tool in order to redesign the tasks in an automotive company and examine its further applications. In the present study, 12 repetitive work cycles consisting of 78 tasks were evaluated in a vehicle assembly. Each task was analyzed separately in terms of posture, force, duration, repetition and vibration using PERA, ManTRA and cube model. Those sub-tasks, in each cycle, which had the highest risk score were identified as the most risky part of the work cycle and considered in the job redesign process. The results show that most of the work cycles are at high-risk level of which shoulders, elbows and head/neck had the most duration of the stressful postures respectively. Also the high-risk tasks in each work cycle were identified and prioritized to be corrected. The results of this study indicate that the common ergonomic risk assessment methods focus on risk level of each body region and therefore the corrective actions would be taken generally, while PERA method is not only capable to assess the body’s postural risks, but also a systematic tool to analyze the complicated tasks and detect the risk sources of a work cycle by breaking it down into its sub-tasks. So it could be more efficient, in job redesign, to figure out some way to modify the work cycle just by focusing on those stressful parts.