Ergonomics-aware operator-task allocation and scheduling in flexible job shop systems

In the context of Industry 5.0, worker well-being is a central tenet within the production process. This research work aims to contribute to this goal by integrating ergonomic factors into task allocation and scheduling while maintaining high productivity. An ergonomics-aware operator-task allocation and scheduling algorithmic framework is developed for a flexible job shop production system to minimise the makespan while ensuring that the maximum physical burden on each operator is not exceeded. The proposed algorithmic framework can integrate any method that assesses the composite ergonomic load on an operator who has been assigned multiple tasks. It can handle several ergonomic measurements of different risk factors with their predefined threshold to ensure safety and efficiency. This flexibility enables decision-makers to select the best measures for their needs. This framework is tested on small to moderate-sized instances, and the numerical experiments show that the proposed algorithmic framework converges to a solution satisfying the ergonomic risk requirement, at the expense of only a slight increase in the makespan. The expected reduction in ergonomics-related injuries in companies adopting this framework would result in an actual productivity gain, which may turn out to be significantly higher than the minor loss due to the increased makespan.