Cross-disciplinary method for predicting and reducing human error probabilities in manual assembly operations

Abstract

Currently, methods for the evaluation of human reliability are mainly applied in safety critical industries (aerospace engineering, nuclear engineering). The Expert System for Task Taxonomy (ESAT) was developed to evaluate the error rate of control and surveillance activities in safety critical areas. In contrast, currently industrial assembly processes are mainly developed concerning an optimal use of the time factor. In this article, the suitability of ESAT for the evaluation of human reliability in manual assembly operations will be examined. By the analysis of an exemplarily considered assembly process it is shown whether and how its work content can be depicted by the ESAT method. In this context, it is also analysed how a modification of the marginal conditions – e.g. the level of specification – affects the calculation results. In the first analysis six manual assembly operations from the automotive industry were analysed and appropriate ESAT-data for its sequences of action were calculated. As a result, the new method allows quantifying potential human error rates before the start of production and comparing planning alternatives under time and cost aspects early. Consequently, the evaluation of human mistakes during the planning process allows developing not only time-optimised but also quality-optimised manual assembly operations.

Keywords:

• methods time measurement
• Expert System for Task Taxonomy
• manual assembly operations

Acknowledgement

The authors of this paper wish to thank the Deutsche Forschungsgemeinschaft (DFG) for their valuable support in this case study as part of the research project ‘methods time and quality measurement – MTQM’.