Human-centric optimisation in manual picker-to-parts systems: a holistic energy expenditure approach

Despite the increasing automation trends in current Industry 5.0 scenarios, human operators remain a key resource in manual warehouse operations thanks to their flexibility and cost-effectiveness. Ensuring the well-being of workers in manual picker-to-parts systems remains a crucial challenge. Existing methodologies tend to overlook or inadequately consider the energy expenditure that can be provided by workers during manual picking activities, emphasising the need for a more comprehensive approach. In this work, a novel methodology to quantify the working allowable energy expenditure rate (WAEER) of workers is proposed. The approach considers individual (age, sex, body weight) as well as more holistic features such as lifestyle and non-working daily activities to tailor workloads in executing manual picking tasks. By adopting Mixed Integer Linear Programming (MILP), the proposed approach optimises the assignment of picking items by minimising workers' fatigue or by avoiding it through rest allowances. Results obtained highlight the effectiveness of the approach as a planning tool, ensuring the workers' well-being. Future research directions include extending the methodology to hybrid warehouse scenarios or assembly lines. The present article contributes to a forward-thinking framework for human-centric energy-based optimisation within Industry 5.0.