TECHNICAL FIELD

The present disclosure is directed toward manipulating boxes using a zoned gripper.

BACKGROUND

Box-like objects represent a large percentage of objects that need to be picked (i.e., removed from a pallet or holding container) in industrial, manufacturing, logistics, and commercial environments. Typically, box-like objects are characterized by at least one substantially planar picking surface. Conventionally, during robotic picking, a picking robot handles known sizes, numbers, and types of boxes arranged in a uniform manner on a structured pallet. Using mechanical fixtures, some current systems pre-position a pallet of boxes so that a robot can pick them from known pre-programmed locations. Any deviation from this known structure, either in the size of the box, the number of boxes, or the location of boxes results in failure of the system. Unfortunately, computer-vision-based systems often rely on the boxes having clean edges at their boundaries and cannot accurately determine size and/or position of boxes that have advertising, printed characters, printed logos, pictures, color, or any other texture on them. Such boxes have visual edges on their faces (i.e., edges that do not correspond to an actual physical boundary of the box). Because current computer-vision-based systems cannot distinguish the physical edges between two different boxes from other visual edges on the faces of boxes, these systems tend to misjudge the size and position of the box(es). Problematically, picking and moving the box where the system has misjudged its size and location may either cause the box to slip from the grasp of the robot or may cause the robot to pick two or more boxes where it should have picked only one.

SUMMARY

One aspect of the disclosure provides a method of manipulating boxes using a zoned griper. The method includes receiving, at a control system, a minimum box size for a plurality of boxes varying in size. Here, the plurality of boxes are located in a walled container. The robot includes a gripper with a plurality of vacuum suction cups. The method also includes dividing, by the control system, a grip area of the gripper into a plurality of zones based on the minimum box size. The method further includes locating, by the control system, a set of candidate boxes of the plurality of boxes based on an image from a visual sensor. For each zone of the plurality of zones, the method additionally includes, determining, by the control system, an overlap of a respective zone with one or more neighboring boxes to the set of candidate boxes where the neighboring boxes identified by the image from the visual sensor. The method also includes determining, by the control system, a grasp pose for a target candidate box of the set of candidate boxes that avoids one or more walls of the walled container. The method further includes executing, by the control system, the grasp pose to lift the target candidate box by the gripper where the gripper activates each zone of the plurality of zones that does not overlap a respective neighboring box to the target candidate box.

Implementations of the disclosure may include one or more of the following optional features. In some implementations, the method also includes determining, by the control system, that the grasp pose includes minimum coverage of the target candidate box where the minimum coverage corresponds to an area providing suction force sufficient to lift the target candidate box. In some examples, the method additionally includes determining, by the control system, that a part-presence sensor overlaps with the target candidate box by a sufficient margin where the sufficient margin triggers the part-presence sensor to communicate a presence of the target candidate box. Determining the grasp pose for target candidate box may include offsetting the grasp pose based on a location of the one or more walls of the walled container. In some configurations, the method also includes determining, by the control system, that the gripper has lifted the target candidate box a threshold height and activating, by the control system, all zones of the gripper. In some examples, the method further includes identifying, by the control system, a feature of the walled container to avoid during removal of the target candidate box from the walled container and determining, by the control system, a motion path for removal of the target candidate box from the walled container where the motion path avoids the identified feature of the walled container.

Optionally, the plurality of zones may cascade across the plurality of vacuum suction cups of the gripper. The plurality of boxes varying in size may correspond to rectilinear objects. In some example, the plurality of boxes varying in size corresponds to the plurality of boxes varying in height. The grasp pose may correspond to a position of the gripper defined by a set of vacuum suction cups of the plurality of vacuum suction cups overlapping a top surface of a target candidate box.

Another aspect of the disclosure provides a robot that manipulates boxes using a zoned griper. The robot includes a visual sensor, a gripper, and a control system. The gripped includes a plurality of vacuum suction cups and the control system is configured to perform operations. The operations include receiving a minimum box size for a plurality of boxes varying in size, the plurality of boxes located in a walled container. The operations also include dividing a grip area of the gripper into a plurality of zones based on the minimum box size. The operations further include locating a set of candidate boxes of the plurality of boxes based on an image from the visual sensor. For each zone of the plurality of zones, the operations additionally include determining an overlap of a respective zone with one or more neighboring boxes to the set of candidate boxes, the neighboring boxes identified by the image from the visual sensor. The operations also include determining a grasp pose for a target candidate box of the set of candidate boxes that avoids one or more walls of the walled container. The operations further include executing the grasp pose to lift the target candidate box by the gripper to the control system, the grasp pose actuating each zone of the plurality of zones that does not overlap a respective neighboring box to the target candidate box.

This aspect may include one or more of the following optional features. In some implementations, the operations also include determining that the grasp pose includes minimum coverage of the target candidate box where the minimum coverage corresponds to an area providing suction force sufficient to lift the target candidate box. In some examples, the operations additionally include determining that a part-presence sensor overlaps with the target candidate box by a sufficient margin where the sufficient margin triggers the part-presence sensor to communicate a presence of the target candidate box. Determining the grasp pose for target candidate box may include offsetting the grasp pose based on a location of the one or more walls of the walled container. In some configurations, the operations also include determining that the gripper has lifted the target candidate box a threshold height and activating, by the control system, all zones of the gripper. In some examples, the operations further include identifying a feature of the walled container to avoid during removal of the target candidate box from the walled container and determining a motion path for removal of the target candidate box from the walled container where the motion path avoids the identified feature of the walled container.

The details of one or more implementations of the disclosure are set forth in the accompanying drawings and the description below. Other aspects, features, and advantages may be apparent from the description and drawings, and from the claims.

