Object pickup strategies for a robotic device

Patent metadata

Field	Value
Publication number	US-9987746-B2
Application number	US-201615093118-A
Country	US
Kind code	B2
Filing date	Apr 7, 2016
Priority date	Mar 15, 2013
Publication date	Jun 5, 2018
Grant date	Jun 5, 2018

Abstract

Example embodiments may relate to methods and systems for selecting a grasp point on an object. In particular, a robotic manipulator may identify characteristics of a physical object within a physical environment. Based on the identified characteristics, the robotic manipulator may determine potential grasp points on the physical object corresponding to points at which a gripper attached to the robotic manipulator is operable to grip the physical object. Subsequently, the robotic manipulator may determine a motion path for the gripper to follow in order to move the physical object to a drop-off location for the physical object and then select a grasp point, from the potential grasp points, based on the determined motion path. After selecting the grasp point, the robotic manipulator may grip the physical object at the selected grasp point with the gripper and move the physical object through the determined motion path to the drop-off location.

First claim

We claim:

1. A method comprising:
determining, by a computing device, two or more potential grasp points on a physical object corresponding to points at which a gripper attached to a robotic manipulator is operable to grip the physical object;
determining a drop-off location for the physical object;
making a determination that the robotic manipulator dropping off the physical object at the drop-off location while gripping the physical object at a given grasp point, from among the two or more potential grasp points, is expected to result in a collision between the physical object and another obstructing object positioned at the drop-off location;
in response to making the determination, rejecting the given grasp point as being one of the two or more potential grasp points, thereby resulting in one or more remaining potential grasp points other than the given grasp point;
selecting a grasp point from among the one or more remaining potential grasp points; and
providing instructions to cause the robotic manipulator to grip the physical object at the selected grasp point with the gripper and move the physical object to the drop-off location.

2. The method of claim 1 , further comprising:
receiving at least one sensor scan of the physical object, wherein determining the two or more potential grasp points on the physical object is based at least in part on the at least one sensor scan of the physical object.

3. The method of claim 1 , wherein determining the two or more potential grasp points comprises identifying two or more flat areas on the physical object and determining that the identified two or more flat areas are each a potential grasp point.

4. The method of claim 3 , wherein the gripper uses suction to grip objects, and wherein the identified two or more flat areas are each larger in area than a gripping surface of the gripper.

5. The method of claim 1 , wherein determining the two or more potential grasp points comprises identifying a first point on a first surface of the physical object and a second point on a second surface of the physical object, wherein the first and second surfaces have opposite surface orientations, and wherein the gripper comprises a two finger gripper configured to clamp onto the identified first and second points.

6. The method of claim 1 , wherein the given grasp point is a first given grasp point, the method further comprising:
making a further determination that the robotic manipulator moving towards the physical object in order to grip the object at a second given grasp point, from among the two or more potential grasp points, is expected to result in a collision of the robotic manipulator with a further obstructing object; and
in response to making the further determination, rejecting the second given grasp point as being one of the two or more potential grasp points, thereby resulting in one or more remaining potential grasp points other than the first and second given grasp point.

7. The method of claim 1 , wherein the given grasp point is a first given grasp point, the method further comprising:
determining a motion path for the gripper to follow in order to move the physical object to the drop-off location for the physical object;
making a further determination that the robotic manipulator moving the physical object through the determined motion path while gripping the physical object at a second given grasp point, from among the two or more potential grasp points, is expected to result in a collision between the physical object and a further obstructing object; and
in response to making the further determination, rejecting the second given grasp point as being one of the two or more potential grasp points, thereby resulting in one or more remaining potential grasp points other than the first and second given grasp point,
wherein moving the physical object to the drop-off location comprises moving the physical object through the determined motion path to the drop-off location.

8. The method of claim 7 , wherein determining the motion path for the gripper comprises determining a sequence of joint angles for the robotic manipulator that minimizes a cost function, wherein the cost function comprises a plurality of weighted criterion associated with different characteristics of the motion path.

9. The method of claim 7 , wherein determining the motion path for the gripper comprises determining a sequence of cartesian coordinates for the physical object that minimizes a cost function, wherein the cost function comprises a plurality of weighted criterion associated with different characteristics of the motion path.

10. The method of claim 1 , wherein selecting the grasp point from among the one or more remaining potential grasp points comprises selecting a grasp point from the one or more remaining potential grasp points that minimizes a cost function, wherein the cost function comprises a plurality of weighted criterion associated with different characteristics of the grasp point.

11. The method of claim 1 , wherein selecting the grasp point from among the one or more remaining potential grasp points comprises selecting a grasp point from the one or more remaining potential grasp points that minimizes a cost function, wherein the cost function comprises:
a plurality of weighted criterion associated with different characteristics of a pose of the robotic manipulator at the grasp point; and
a plurality of weighted criterion associated with different characteristics of a pose of the robotic manipulator at the drop-off location.

12. The method of claim 1 , further comprising:
storing information, in a memory storage, comprising one or more of: (i) the selected grasp point and (ii) a performance evaluation of the selected grasp point based on the movement of the physical object to the drop-off location.

13. The method of claim 12 , further comprising:
using the stored information to determine other grasp points for the robotic manipulator to use in picking up additional physical objects from a physical environment.

14. The method of claim 12 , further comprising:
providing the stored information to a second robotic manipulator to determine grasp points for the second robotic manipulator to use to pick up physical objects from a physical environment.

15. The method of claim 1 , further comprising:
determining one or more adjacent physical objects in contact with the physical object; and
providing instructions to cause the robotic manipulator to create space between the physical object and the one or more adjacent physical objects by using the gripper to cause the physical object to alternately move in at least two opposing directions prior to moving the physical object to the drop-off location.

16. The method of claim 1 , further comprising:
identifying a fiducial mark at a particular point on a virtual object representative of the physical object, wherein the fiducial mark indicates a reference point for gripping the physical object; and
determining a point on the physical object corresponding to the fiducial mark as one of the two or more potential grasp points.

17. A system comprising:
a robotic manipulator;
a gripper attached to the robotic manipulator; and
a control system configured to:
determine two or more potential grasp points on a physical object corresponding to points at which the gripper is operable to grip the physical object;
determine a drop-off location for the physical object;
make a determination that the robotic manipulator dropping off the physical object at the drop-off location while grippin

Assignees

• X Dev Llc

Inventors

• Bradski Gary
• Konolige Kurt
• Rublee Ethan
• Straszheim Troy
• Strasdat Hauke
• Hinterstoisser Stefan
• Croft Steve
• Zevenbergen John

Classifications

• B25J9/1671 Primary

  characterised by simulation, either to verify existing program or to create and verify new program, CAD/CAM oriented, graphic oriented programming systems · CPC title

• B25J9/163 Primary

  learning, adaptive, model based, rule based expert control · CPC title

• G06T7/55

  from multiple images · CPC title

• G06T2200/04

  involving 3D image data · CPC title

• B65H67/065

  Manipulators with gripping or holding means for transferring the packages from one station to another, e.g. from a conveyor to a creel trolley · CPC title