Method for correcting position of automated-guided vehicle and apparatus therefor

• US 6,256,560 B1
• Filed: 02/22/2000
• Issued: 07/03/2001
• Est. Priority Date: 02/25/1999
• Status: Expired due to Term

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Kim, Jin-ki, Kal, Myung-joon
• Primary Examiner(s): Cuchlinski, Jr., William A.
• Assistant Examiner(s): ARTHUR JEANGLAUDE, GERTRUDE
• Application Number:
  US09/510,146
• Time in Patent Office: 497 Days
• Field of Search: 701/23, 701/26, 701/69, 701/210, 180/167, 180/168, 318/568.12
• US Class Current: 701/23
• CPC Class Codes: G05D 1/0246 using a video camera in combination with image processing means

Abstract

A method for correcting an actual stop position of an AGV for carrying out a task while stopped along a travelling path includes the steps of: a) establishing at least one reference position as a basis for determining an actual stop position of the AGV on the travelling path; b) ascertaining the reference position where the AGV actually stops, based on image data of the actual stop position, and calculating the difference between the reference position and the actual stop position; c) ascertaining whether the difference is within an allowable limit of a predetermined reference value; and d) controlling the AGV to make the difference within the allowable limit of the reference value if the difference is not within the allowable limit. With this method, and an apparatus therefor, the actual stop position of the AGV on the travelling path can be easily determined, and the actual stop position of the vehicle body or the manipulator of the AGV can be easily corrected to be located at respective predetermined correct working positions.

Claims

1. A method for correcting an actual stop position of an AGV for carrying out a task while the AGV is stopped at a workplace located along a travelling path for the AGV, said method comprising the steps of:

a) establishing at least one reference position at the workplace which serves as a reference for determining an actual stop position of the AGV stopped at that workplace on the travelling path;

b) ascertaining the reference position of the workplace where the AGV actually stops, based on image data at the actual stop position, and calculating a difference between the reference position and the actual stop position;

c) ascertaining whether the difference is within an allowable limit of a predetermined reference value; and

d) controlling the AGV to make the difference within the allowable limit of the predetermined reference value if the difference is not within the allowable limit.

2. The method according to claim 1, wherein one of a position of a vehicle body of the AGV and a position of a manipulator mounted on the AGV is corrected in said controlling step (d).

3. The method according to claim 1, wherein the reference value is an offset value of the reference position corresponding to a predetermined correct working position for the AGV, relative to the correct working position.

4. The method according to claim 3:

wherein said establishing step (a) comprises the sub-step of;

providing a position indicator at the workplace for determining the reference position and the actual stop position; and

wherein said ascertaining step (b) comprises the sub-steps of;

ascertaining data of the reference position and the actual stop position from the position indicator; and

calculating the difference between the actual stop position and the reference position, based on the ascertained data.

5. The method according to claim 4, wherein the position indicator includes a barcode for ascertaining the reference position and the actual stop position.

6. The method according to claim 4, wherein said position indicator includes a barcode for ascertaining the reference position and the actual stop position, and a correction mark having reference coordinates for determining how far the actual stop position is deviated from the correct working position.

7. The method according to claim 6, wherein the correction mark is formed in pairs on respective sides of the barcode, and an indicia with reference coordinates is formed at the center of each correction mark.

8. The method according to claim 4, wherein the difference is obtained by measuring deviation of axes of the reference position from the stop position.

9. The method according to claim 6, wherein the reference coordinates are orthogonal coordinates, and the deviation is indicated as deviation distances relative to axes of the orthogonal coordinates and a deviation angle relative to one axis of the orthogonal coordinates.

10. The method according to claim 3, wherein the offset value is obtained by setting reference coordinates with respect to the reference position and measuring deviation of the reference coordinates from the correct working position.

11. A method for correcting an actual stop position of an AGV equipped with a manipulator for carrying out a task while the AGV is stopped at a workplace located along a travelling path for the AGV, said method comprising the steps of:

a) establishing at least one reference position at the workplace which serves as a reference for determining an actual stop position of the AGV stopped at that workplace on the travelling path;

b) ascertaining the reference position of the workplace where the manipulator actually stops, based on image data at the actual stop position, and calculating a difference between the reference position and the actual stop position;

c) ascertaining whether the difference is within an allowable limit of a predetermined the reference value; and

d) controlling the manipulator to make the difference within the allowable limit of the predetermined reference value if the difference is not within the allowable limit.

12. The method according to claim 11, wherein the reference value is an offset value of the reference position corresponding to a predetermined correct working position for the manipulator, relative to the correct working position.

13. The method according to claim 12:

wherein the establishing step (a) comprises the sub-step of;

providing a position indicator for determining the reference position; and

wherein the ascertaining step (b) comprises the sub-steps of;

ascertaining data of the reference position and the actual stop position from the position indicator;

calculating the difference between the actual stop position and the reference position, based on the ascertained data.

14. The method according to claim 13, wherein the position indicator includes a barcode for ascertaining the reference position and the actual stop position.

15. The method according to claim 13, wherein the position indicator includes a barcode for ascertaining the reference position and the actual stop position, and a correction mark having reference coordinates for determining how far the actual stop position is deviated from the correct working position.

16. The method according to claim 15, wherein the correction mark is formed in pairs on respective sides of the barcode, and an indicia with reference coordinates is formed at the center of each correction mark.

17. The method according to claim 15, wherein the reference coordinates are orthogonal coordinates, and the deviation is indicated as deviation distances relative to the axes of the orthogonal coordinates and a deviation angle relative to one axis of the orthogonal coordinates.

18. The method according to claim 13, wherein the offset value is obtained by setting reference coordinates with respect to the reference position and measuring deviation of the reference coordinates from the correct working position.

19. The method according to claim 18, wherein the difference is obtained by measuring deviation of the reference coordinates from the actual stop position.

20. An apparatus for correcting an actual stop position of an AGV equipped with a manipulator for carrying out a task while the AGV is stopped at a workplace located along a travelling path for the AGV, said apparatus comprising:

at least one position indicator installed at the workplace on the travelling path, said position indicator determining a reference position at the workplace;

ascertaining means for ascertaining data of the reference position from the position indicator;

an image data processor which calculates a difference between the actual stop position of the manipulator and the reference position, based on the ascertained data of said ascertaining means;

a memory which stores a predetermined reference value;

an arithmetic logic unit which calculates a position correction value to correct an actual position of the manipulator by comparing the difference and the predetermined reference value; and

a controller which controls the manipulator according to the position correction value.

21. The apparatus according to claim 20, wherein the reference value is an offset value of the reference position corresponding to a predetermined correct working position for the manipulator, relative to the correct working position.

22. The apparatus according to claim 20, wherein said ascertaining means is a CCD camera.