MOTION PATH SEARCH DEVICE AND METHOD OF SEARCHING FOR MOTION PATH

• US 20120239193A1
• Filed: 05/29/2012
• Published: 09/20/2012
• Est. Priority Date: 11/12/2010
• Status: Active Grant

• Current Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Original Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Inventors: MIZUTANI, Kenji
• Granted Patent: US 8,494,677 B2
• Time in Patent Office: Days
• US Class Current: 700/250
• CPC Class Codes: G05B 19/423 Teaching successive positions by walk-through, i.e. the tool head or end effector being grasped and guided directly, with or without servo-assistance, to follow a path
• CPC Class Codes: G05B 2219/40437 Local, directly search robot workspace

Abstract

A motion path search device includes: a motion space identification unit which identifies, as first spaces, three-dimensional spaces swept through by a movable part in direct teaching operations performed by an operator; a spatial difference calculation unit which calculates a first differential space that is a part of one of the first spaces identified as a result of one of the direct teaching operations and has no overlap with an other of the first spaces, identified as a result of an other of the direct teaching operations that precedes the one of the direct teaching operations; a feedback unit which provides the operator with information regarding the first differential space; and a path search unit which searches for a motion path of the movable part within a first accessible space resulting from combining the first spaces after the direct teaching operations.

Claims

1. A motion path search device comprising:

a first space identification unit configured to identify, as first spaces, three-dimensional spaces swept through by a movable part of a robot in a plurality of direct teaching operations performed by an operator to teach a motion to the robot by directly moving the robot;

a second space identification unit configured to identify, as second spaces, three-dimensional spaces swept through by at least a portion of a body of the operator in the direct teaching operations;

a spatial difference calculation unit configured to calculate a first differential space and a second differential space, the first differential space being a part of one of the first spaces which is identified as a result of one of the direct teaching operations and having no overlap with an other of the first spaces which is identified as a result of an other of the direct teaching operations that precedes the one of the direct teaching operations, and the second differential space being a part of one of the second spaces which is identified as a result of the one of the direct teaching operations and having no overlap with an other of the second spaces which is identified as a result of the other of the direct teaching operations that precedes the one of the direct teaching operations;

a feedback unit configured to provide the operator with at least one of information regarding the first differential space and information regarding the second differential space;

a space combining unit configured to combine a first accessible space and a second accessible space, the first accessible space being a combination of the first spaces identified as results of the direct teaching operations, and the second accessible space being a combination of the second spaces identified as results of the direct teaching operations; and

a path search unit configured to search for a motion path of the movable part within a space resulting from the combining by said space combining unit, after the direct teaching operations are completed.

2. The motion path search device according to claim 1,

wherein said feedback unit is configured to provide, as the information regarding the first differential space, a volume ratio of the first differential space to the first space identified as the result of the other of the direct teaching operations that precedes the one of the direct teaching operations.

3. The motion path search device according to claim 2,

wherein said first space identification unit is configured to identify, as the first spaces, spaces each composed of a set of voxels included in the robot at points of time in a corresponding one of the direct teaching operations, the voxels being among voxels composing three-dimensional space, and

said feedback unit is configured to provide, as the volume ratio, a ratio of the number of voxels composing the first differential space to the number of voxels composing the first space identified as the result of the other of the direct teaching operations that precedes the one of the direct teaching operations.

4. The motion path search device according to claim 1,

wherein said feedback unit is configured to provide, as the information regarding the second differential space, a volume ratio of the second differential space to the second space identified as the result of the other of the direct teaching operations that precedes the one of the direct teaching operations.

5. The motion path search device according to claim 4,

wherein said second space identification unit is configured to identify, as the second spaces, spaces each composed of a set of voxels included in the at least a portion of the body of the operator at points of time in a corresponding one of the direct teaching operations, the voxels being among voxels composing three-dimensional space, and

said feedback unit is configured to provide, as the volume ratio, a ratio of the number of voxels composing the second differential space to the number of voxels composing the second space identified as the result of the other of the direct teaching operations that precedes the one of the direct teaching operations.

6. The motion path search device according to claim 1,

wherein said feedback unit is configured to provide one of the information regarding the first differential space and the information regarding the second differential space, depending on a result of comparison between the first differential space and the second differential space.

7. The motion path search device according to claim 6,

wherein said feedback unit is configured to provide the information regarding the first differential space when the first differential space is smaller than the second differential space, and with the information regarding the second differential space when the second differential space is smaller than the first differential space.

8. The motion path search device according to claim 1, further comprising

a posture difference calculation unit configured to calculate a difference between one or more values indicating a posture of the operator at a start of an other of the direct teaching operations which immediately precedes the one of the direct teaching operations and one or more values indicating a posture of the operator at a start of the one of the direct teaching operations,

wherein said feedback unit is further configured to provide the operator with information regarding the posture, based on the calculated difference, at the start of the one of the direct teaching operations.

9. The motion path search device according to claim 8,

wherein the robot has a handle part which the operator grasps to perform the direct teaching operations, and

the postures of the operator are directions of an elbow of the operator as seen from the handle part.

10. The motion path search device according to claim 9,

wherein the values indicating the postures include first values and second values, the first values each indicating an angle of a corresponding one of the direction of the elbow with respect to a plane perpendicular to an axis of the handle part, and the second values each indicating an angle between the corresponding one of the directions of the elbow and the plane,

said posture difference calculation unit is configured to calculate a difference between the first values and a difference between the second values, and

said feedback unit is configured to provide the information regarding the posture, based on a result of comparison between the difference between the first values and the difference between the second values.

11. The motion path search device according to claim 8,

wherein said feedback unit is configured to provide the information regarding the posture at the start of the one of the direct teaching operations when the second differential space is smaller than the first differential space as a result of the other of the direct teaching operations which immediately precedes the one of the direct teaching operations.

12. A method for searching for a motion path, comprising:

identifying, as first spaces, three-dimensional spaces swept through by a movable part of a robot in a plurality of direct teaching operations performed by an operator to teach a motion to the robot by directly moving the robot;

identifying, as second spaces, three-dimensional spaces swept through by at least a portion of a body of the operator in the direct teaching operations;

calculating a first differential space and a second differential space, the first differential space being a part of one of the first spaces which is identified as a result of one of the direct teaching operations and having no overlap with an other of the first spaces which is identified as a result of an other of the direct teaching operations that precedes the one of the direct teaching operations, and the second differential space being a part of one of the second spaces which is identified as a result of the one of the direct teaching operations and having no overlap with an other of the second spaces which is identified as a result of the other of the direct teaching operations that precedes the one of the direct teaching operations;

providing the operator with at least one of information regarding the first differential space and information regarding the second differential space;

combining a first accessible space and a second accessible space, the first accessible space being a combination of the first spaces identified as results of the direct teaching operations, and the second accessible space being a combination of the second spaces identified as results of the direct teaching operations; and

searching for a motion path of the movable part within a space resulting from said combining, after the direct teaching operations are completed.

13. A non-transitory computer-readable recording medium for use in a computer, said recording medium having a computer program recorded thereon for causing the computer to execute the method of searching for a motion path according to claim 12.