Investigating different manual picking workstations for robotized and automated warehouse systems: Trade-offs between ergonomics and productivity aspects

Robotized and Automated Warehouse Systems are widely used in logistics systems due to their efficiency and compactness. Among all aspects to include during tactical and strategic decisions, the number and the design configuration of the picking workstations represent the most critical decision since they influence the conveyor system path and length and the efficiency and productivity of the entire logistics system. Further, the proper workstation design reduces ergonomics risks and, thus, ensures a better quality of work and safety. Nevertheless, many studies on parts-to-picker systems have focused on global system performance, while ergonomics and their influence on system efficiency have often been neglected. For these reasons, in this paper, we aim to close the gap by investigating both ergonomic assessment and picking workstation configurations in an integrated way. Based on the results obtained, managerial guidelines are provided by highlighting the pros and cons of each configuration. Results demonstrate that the suitable solution depends heavily on the delivery order profile and on the time necessary to pick a customer order line. Configurations with the storage bins placed inclined, placed above the order bin and in front of the worker lead to better posture and lower picking time. Further, additional parameters, such as the time required to change the storage bin, the number of items to pick from each storage bin, strongly influence the choice of the most suitable configuration. The results of this paper represent fundamental guidelines to allow managers to carry out correct feasibility studies in terms of expected costs, performance and required spaces.