Puzzle-based systems (PBS), store unit loads in very high density, without consuming space for transport aisles. In such systems, each load is stored on a moving device (conveyor module or transport vehicle), making these systems very expensive to build and maintain. We propose a new type of PBS system where loads are moved by a small number of autonomous mobile robots (AMRs). We formulated an integer linear programming (ILP) model which minimizes the retrieval time and the number of load and vehicle movements, combined with a 3-phase heuristic (3PH) method, which significantly outperforms the heuristic methods known to date and solve large instances sufficiently fast, using a relatively small number of AMR’s.

UNMET NEED
Classic warehouses are based on shelves and transport aisles in which a person / vehicle / autonomous vehicle / robot passes to collect the load. In such a configuration there is a great waste of valuable storage space wasted on logistics areas and aisles.
In response to this waste, it was proposed to manage warehouses in a beehive / puzzle configuration – PBS (puzzle-based storage). In such configuration each load is stored on a moving device (conveyor module or transport vehicle), making these systems very expensive to build and maintain.

OUR SOLUTION
We propose a new type of PBS where loads are moved by a small number of autonomous mobile robots (AMRs). The AMRs can travel freely underneath loads, lift them and move them to other locations. When a specific load is requested, this load is carried to the I/O point, while other (blocking) loads are moved to clear the path for the requested load. In this process, each AMR can engage and disengage from loads multiple times. The PBS-AMR system is appropriate when a high storage density is desired and the required throughput capacity is moderate. AMRs are hard to analyze, as all the AMRs can move simultaneously with or without loads. Therefore, researchers have formulated a (ILP) model which minimizes the retrieval time and the number of load and vehicle movements, combined with a 3-phase heuristic (3PH) method, which significantly outperforms the heuristic methods known to date and solves large instances sufficiently fast. All of this is done using a relatively small number of AMR’s.

APPLICATIONS
A new approach and method for managing puzzle-based storage (PBS) systems using automated mobile robots (AMR) for Optimal retrieval.

STATUS
Initial proof of concept was achieved.

INTELLECTUAL PROPERTY
provisional patent application.

REFERENCES
1. Yossi Bukchin, Tal Raviv (2021). A comprehensive toolbox for load retrieval in puzzle-based storage systems with simultaneous movements. https://www.researchgate.net/p…