Harmonizing ergonomics and economics of assembly lines using collaborative robots and exoskeletons
In the design phase of assembly lines, the harmonization of the frequently conflicting ergonomic and economic objectives is particularly important to enable both humane and efficient assembly. Recent technological developments such as collaborative robots and exoskeletons can support human workers in their assembly tasks and have the potential to enable both ergonomic enhancements and cost reductions. However, ergonomic factors in assembly line balancing are still underrepresented in literature. Exoskeletons have not yet been considered in assembly line balancing. We develop a mixed-integer programming model for balancing assembly lines under consideration of ergonomic and economic objectives and the availability of novel technologies. We validate our model using test instances from literature and find collaborative robots and exoskeletons to be ergonomically and economically viable options for partial automation of manual assembly. We present Pareto-optimal frontiers for the visual inspection of the optimization results and we quantify the potential reductions in costs and biomechanical load to support decision-makers in evaluating the technologies based on their preferences. Our approach is capable to identify nonsupported nondominated solutions, which allows for a stepwise reduction of biomechanical load with only a minor increase in costs. In this article, for the first time, the trade-offs between ergonomic and economic objectives in assembly line balancing are discussed and the potential to harmonize the conflicting objectives using collaborative robots and exoskeletons is evaluated.
Assembly line balancing