Picking apparatus and picking method

• US 9,604,364 B2
• Filed: 05/08/2015
• Issued: 03/28/2017
• Est. Priority Date: 05/08/2014
• Status: Active Grant

• Current Assignee: Toshiba Kikai Kabushiki Kaisha (Toshiba Machine Company Limited)
• Original Assignee: Toshiba Kikai Kabushiki Kaisha (Toshiba Machine Company Limited)
• Inventors: Nishihara, Yasunori
• Primary Examiner(s): Sample, Jonathan L
• Application Number:
  US14/708,005
• Publication Number:
  US 20150321354A1
• Time in Patent Office: 690 Days
• US Class Current: 1/1
• CPC Class Codes: B25J 9/1697 Vision controlled systems
• CPC Class Codes: G05B 2219/37567 3-D vision, stereo vision, with two cameras
• CPC Class Codes: G05B 2219/39476 Orient hand relative to object
• CPC Class Codes: G05B 2219/40053 Pick 3-D object from pile of objects

Abstract

A picking apparatus includes: a three-dimensional imaging device configured to three-dimensionally-image workpieces contained in bulk in a container; a robot arm having a hand capable of gripping a workpiece; and a control device configured to control an operation of the robot arm; the control device is configured: to recognize a position and a posture of a target workpiece, based on an imaging result of the three-dimensional imaging device; to obtain an gripping position of the workpiece and an approach vector thereof, based on the recognized position and posture information; to calculate an intersection point between a straight line extending along the approach vector through the gripping position and a plane including an opening of the container; and to judge whether the workpiece can be picked or not, based on a positional relationship between the intersection point and the opening.

Claims

1. A picking apparatus comprising:

a three-dimensional imaging device configured to three-dimensionally image workpieces contained in bulk in a container;

a robot arm comprising a hand configured to grip a workpiece; and

a control device configured to control an operation of the robot arm;

wherein the control device is configured;

to recognize a position and a posture of a target workpiece, based on an imaging result of the three-dimensional imaging device;

to obtain a gripping position of the workpiece and an approach vector of the gripping position, based on the recognized position and posture information;

to calculate an intersection point between a straight line extending along the approach vector through the gripping position and a plane including an opening of the container; and

to determine whether the workpiece can be picked or not, based on a positional relationship between the intersection point and the opening.

2. The picking apparatus according to claim 1, wherein the control device is configured:

to determine whether a condition, in which the intersection point is located inside the opening and a shortest distance between the intersection point and a peripheral part defining the opening is larger than a predetermined value, is satisfied or not;

to cause the robot arm to pick the workpiece, in response to determining the condition is satisfied; and

not to cause the robot arm to pick the workpiece, in response to determining the condition is not satisfied.

3. The picking apparatus according to claim 2, wherein

the predetermined value is 1 to 1.1 times any larger one of a maximum value of a distance between the gripping position and a profile of the workpiece in a direction orthogonal to the approach vector and a maximum value of a distance between the gripping position and a profile of the hand in the direction orthogonal to the approach vector.

4. The picking apparatus according to claim 1, wherein

the control device is configured to operate the robot arm such that the hand is brought into contact with a peripheral part defining the opening, to thereby obtain a position of the peripheral part.

5. The picking apparatus according to claim 1, further comprising a sensor configured to detect a position of a position indicating marker disposed around the opening,

wherein the control unit is configured to obtain a position of a peripheral part defining the opening based on a detection result of the sensor.

11. The picking apparatus according to claim 2, wherein

the control device is configured to operate the robot arm such that the hand is brought into contact with a peripheral part defining the opening to obtain a position of the peripheral part.

12. The picking apparatus according to claim 3, wherein

the control device is configured to operate the robot arm such that the hand is brought into contact with a peripheral part defining the opening to obtain a position of the peripheral part.

13. The picking apparatus according to claim 2, further comprising a sensor configured to detect a position of a position indicating marker disposed around the opening,

wherein the control unit is configured to obtain a position of a peripheral part defining the opening based on a detection result of the sensor.

14. The picking apparatus according to claim 3, further comprising a sensor configured to detect a position of a position indicating marker disposed around the opening,

wherein the control unit is configured to obtain a position of a peripheral part defining the opening based on a detection result of the sensor.

6. A picking method comprising:

three-dimensionally imaging workpieces contained in bulk in a container; and

controlling an operation of a robot arm comprising a hand configured to grip a workpiece;

wherein the controlling of the operation of the robot arm includes;

recognizing a position and a posture of a target workpiece, based on an imaging result of the three-dimensionally imaging;

obtaining a gripping position of the workpiece and an approach vector of the gripping position, based on the recognized position and posture information;

calculating an intersection point between a straight line extending along the approach vector through the gripping position and a plane including an opening of the container; and

determining whether the workpiece can be picked or not, based on a positional relationship between the calculated intersection point and the opening.

7. The picking method according to claim 6, wherein

the determining whether the workpiece can be picked or not includes:

determining whether a condition, in which the intersection point is located inside the opening and a shortest distance between the intersection point and a peripheral part defining the opening is larger than a predetermined value, is satisfied or not;

causing the robot arm to pick the workpiece, in response to determining the condition is satisfied; and

not causing the robot arm to pick the workpiece, in response to determining the condition is not satisfied.

8. The picking method according to claim 7, wherein

the predetermined value is 1 to 1.1 times any larger one of a maximum value of a distance between the gripping position and a profile of the workpiece in a direction orthogonal to the approach vector and a maximum value of a distance between the gripping position and a profile of the hand in the direction orthogonal to the approach vector.

9. The picking method according to claim 6, further comprising operating the robot arm such that the hand is brought into contact with a peripheral part defining the opening to obtain a position of the peripheral part.

10. The picking method according to claim 6, further comprising:

detecting a position of a position indicating marker disposed around the opening; and

obtaining a position of a peripheral part defining the opening based on a detection result of the detecting.

15. The picking method according to claim 7, further comprising operating the robot arm such that the hand is brought into contact with a peripheral part defining the opening to obtain a position of the peripheral part.

16. The picking method according to claim 8, further comprising operating the robot arm such that the hand is brought into contact with a peripheral part defining the opening to obtain a position of the peripheral part.

17. The picking method according to claim 7, further comprising:

detecting a position of a position indicating marker disposed around the opening; and

obtaining a position of a peripheral part defining the opening based on a detection result of the detecting.

18. The picking method according to claim 8, further comprising:

detecting a position of a position indicating marker disposed around the opening; and

obtaining a position of a peripheral part defining the opening based on a detection result of the detecting.