SPRP-SS: Single Picker Routing Problem with Scattered Storage

• Applicant: Professor Dr. Stefan Irnich
• Subject Area: Operations Management and Computer Science for Business Administration
• Term: since 2024
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 555303283

Warehouse activities include receiving, storing, picking, packing, and shipping operations. The most important warehouse operations planning problems include designing the warehouse layout, assigning of items to storage locations, compiling picking lists (order batching), and routing pickers through the warehouse (picker routing). In this research project, we address order picking operations in manual and hybrid warehouses where pickers travel through the warehouse to retrieve, based on customer orders, items from the storage locations (picker-to-parts; also AGV-assisted picking). Although there are various ways to automate the picking process, systems based on the person-to-goods principle are still very common in practice. The Single Picker Routing Problem (SPRP) comprises a large class of route optimization problems. Its defining characteristics are the layout of the warehouse, the number and location of start and drop-off points, and the routing policy (exact or rule-based). Modern warehouses often operate as scattered storage warehouses or mixed shelves warehouses. Here, items can be picked from more than one storage location. Scattered storage is now the standard in large warehouses in the business-to-consumer sector (heterogeneous orders with small quantities of individual articles) including big players such as Amazon Europe or Zalando. The goal is the development of new powerful mathematical models and algorithms to solve the SPRP with scattered storage (SPRP-SS), both as a stand-alone problem as well as in multi-level optimization problems, where the lowest-level decisions relate to the routing of a picker. In the latter case, a large number of SPRP-SS instances must be solved. The goal is to provide new and faster solution algorithms for the SPRP-SS and to test them in different settings. This includes both heuristic and exact algorithms.

• DFG Programme: Research Grants
• International Connection: Austria
• Cooperation Partners: Professor Dr. Timo Gschwind; Professor Dr. Ulrich Pferschy