Application of Digital Human Modelling and Factorial Experiments for Workstation Optimization

Abstract: Human-Robot Collaboration (HRC) empower manufacturing workstations by enabling ergonomic and safe working conditions for humans. To design successful HRC, operational and ergonomics aspects must be considered. In this paper, a new methodology is developed to identify factors that can impact physical workload of workers’ performance in a HRC environment. The proposed approach is based on Digital Human Modelling (DHM) and Factorial Design of Experiments. DHM enables to design and evaluate a large number of design configurations with respect to multiple performance measures. However, most of modelling tools focus on graphical aspects and fail to analyze the effect of interactions among different design parameters that play a significant role in the design of workstations. Factorial Experiments addresses these gaps by generating a set of alternative design configurations in a systematic manner. In this study, a HRC workstation design is simulated in JACK software. A set of controllable design parameters (input factors) that may influence the ergonomic risks are defined as number of cobots, task complexity, human's anthropometric characteristics (height and weight) and product features (weight and dimensions). Each factor has two levels as high and low. To reduce the number of runs fractional factorial design algorithm is applied and 32 experiments are generated by using different configurations of factors’ levels. Multi-objective optimization technique applied for five different performance measures that are characterized as cumulative compression, cumulative low back moment exposure on L4/L5, energy expenditure rate, RULA score and cycle time. Main and interaction effects of input factors on performance measures are discussed. The proposed methodology shows the advantages of combining DHM tools, and statistical design approaches such as Factorial Experiments.

Keywords: Digital Human Modelling, Human Robot Collaboration, Physical Ergonomic Risks, Design of Experiments

DOI: 10.54941/ahfe1005019

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