The Static Buffer Reshuffling and Retrieval Problem for Autonomous Mobile Robots

Buffer zones for moveable shelves or pallets with intermediate products are ubiquitous in production systems to decouple production stages. These buffer zones, usually organized by humans in dense grids, pose a challenge for direct access to all unit loads. To access the retrieval unit load, it often becomes necessary to reshuffle blocking unit loads. When autonomous mobile robots supply production machines without human intervention, their responsibilities encompass both the reshuffling of buffer zones and the transportation of unit loads to production cells adhering to the sequence prescribed by the production plan. This paper introduces the buffer reshuffling and retrieval problem, which is a variant of the block relocation problem known from container terminals at shipyards. We propose an integer programming formulation designed for the static variant of the problem. We created an instance generator with customizable layout sizes and found optimal solutions to solve these instances.