Linking human availability and ergonomics parameters in order-picking systems

Most of the warehouse picking systems are based on manual activities, performed by human operators. Therefore, their performances and costs deeply depend on human availability and productivity, affected by the fatigue of operators and the probability of injuries and their gravity. In this paper, a real case studies analysis concerning the ergonomics of different picking warehouses is proposed, from which two functions that link the human availability and the rest allowance to the ergonomics level have been obtained. Furthermore, two different cost models, estimating the total expected cost considering both human availability and rest allowance, have been developed.