Human reliability in manual assembly systems: a Systematic Literature Review

Human error in manual assembly systems affects system reliability, safety and it is one of the most important causes of quality defects. Many researchers have developed methods for Human Reliability Analysis (HRA) with the aim of identifying, modeling, quantifying and reducing human error, mainly in safety-critical industries. This paper addresses human reliability analysis in assembly systems, where most of the employed workforce is currently involved. The main purpose is to systematically investigate the current state-of-the-art on this topic, analyzing and summarizing the theoretical and empirical contents, identifying patterns and research streams, informing the strengths and weakness of selected literature and so highlighting the research and practice opportunities. The results of this study show that a prospective analysis of human reliability in the manual assembly systems until now has been neglected in literature. Nevertheless, HRA methods and assembly specific methodologies and approaches found in literature can be successfully applied to assembly systems, allowing users to predict human error probability and to determine the most significant error influencing factors. Furthermore, the results highlight the role of human error in the occurrence of quality defects (rejected or reworking). This paper, therefore, contributes to the transfer of knowledge about human reliability gained in manual assembly operations, providing practitioners and researchers with a comprehensive overview of this topic and several research opportunities for future studies.