Order fulfillment robot capable of horizontal and vertical motion

Abstract

An order fulfillment system is disclosed including a storage structure and mobile robots capable of moving vertically and horizontally within the storage structure to transfer product totes to and from storage locations within the storage structure. The mobile robots may move along a track system including horizontal rails for horizontal travel of the mobile robot and vertical towers for vertical travel of the mobile robot. The vertical towers include two opposed pairs of tracks having U-shaped slots. The order fulfillment system may further comprise a mobile robot configured to travel vertically and horizontally along the track system to transfer product containers to and from the storage locations in the storage structure, and horizontally about a horizontal deck spanning the storage aisles. The mobile robot includes four wheel assemblies, each assembly including a pair of wheels mounted on ends of a climbing link. When positioned in a vertical tower, the climbing links rotate so that the drive wheels climb up or down the storage structure by engaging within the U-shaped slots of the track. The same wheels may be rotated to facilitate horizontal motion.

What is claimed is: 
     
         1 . A mobile robot configured to access a plurality of storage locations in a storage structure extending in first and second directions, the robot comprising:
 a link rotationally mounted to the mobile robot;   a pair of wheels rotationally mounted to the link at spaced apart locations on the link, the pair of wheels configured to advance the mobile robot along the first direction upon rotation of at least one of the wheels, and the pair of wheels configured to advance the mobile robot along the second direction upon rotation of the link.   
     
     
         2 . The mobile robot of  claim 1 , wherein the at least one of the wheels is driven to rotate by a first motor. 
     
     
         3 . The mobile robot of  claim 2 , wherein the link is driven to rotate by a second motor different than the first. 
     
     
         4 . The mobile robot of  claim 1 , wherein the at least one wheel is configured to advance the mobile robot in a horizontal direction upon rotation of the at least one wheel. 
     
     
         5 . The mobile robot of  claim 4 , wherein the pair of wheels are configured to advance the mobile robot in a vertical direction upon rotation of the link. 
     
     
         6 . A mobile robot configured to travel within a track system to access a plurality of storage locations in a storage structure extending in first and second directions, the track system comprising a vertical tower comprising slotted tracks, the robot comprising:
 a link rotationally mounted to the mobile robot;   a pair of wheels rotationally mounted to the link at spaced apart locations on the link, the pair of wheels configured to advance the mobile robot along the first direction upon rotation of at least one of the wheels, and the pair of wheels configured to advance the mobile robot along the second direction upon rotation of the link to position a first wheel of the pair of wheels in a first set of slotted tracks, and to position a second wheel of the pair of wheels in a second set of slotted tracks.   
     
     
         7 . The mobile robot of  claim 6 , wherein the at least one wheel is configured to advance the mobile robot in a horizontal direction upon rotation of the at least one wheel. 
     
     
         8 . The mobile robot of  claim 7 , wherein the pair of wheels are configured to advance the mobile robot in a vertical direction upon rotation of the link.