Amazon patents robot system to slide storage pods for item retrieval

1. A method comprising: determining a storage block comprising a grid of a plurality of storage pods in a robot-controlled storage field, wherein each storage pod of the plurality of storage pods comprises a plurality of items, and wherein the grid comprises a plurality of cells, wherein each cell of the plurality of cells represents a position within the grid occupiable by a storage pod; determining an item disposed on a first storage pod of the plurality of storage pods; determining a target cell of the plurality of cells, wherein the target cell is a perimeter cell of the storage block; and performing a repeated pathway generation process, wherein each repetition of the repeated pathway generation process comprises: determining, based on a current location of the first storage pod and the target cell, a first pathway d as a shortest pathway from the current location of the first storage pod to the target cell, determining, based on the current location of the first storage pod, a first nearest unoccupied cell, determining, based on the first pathway d and the first nearest unoccupied cell, a second pathway l between a first cell adjacent to the current location of the first storage pod along the first pathway d and the first nearest unoccupied cell, controlling at least a first robotic drive to move a first set of the plurality of storage pods along the second pathway l, wherein movement of the first set of the plurality of storage pods results in the first cell adjacent to the current location being unoccupied, controlling the first robotic drive or a second robotic drive to move the first storage pod to the first cell adjacent to the current location, determining an updated location of the first storage pod, in an instance where the updated location of the first storage pod is not located at the target cell, performing another repetition of the repeated pathway generation process, and in an instance where the updated location of the first storage pod is located at the target cell, ending the repeated pathway generation process.