Position control device and position control method of stevedoring apparatus in industrial vehicle

• US 20040073359A1
• Filed: 07/25/2003
• Published: 04/15/2004
• Est. Priority Date: 01/23/2002
• Status: Active Grant

• Current Assignee: Kabushiki Kaisha Toyota Jidoshokki (Toyota Motor Corporation)
• Original Assignee: Kabushiki Kaisha Toyota Jidoshokki (Toyota Motor Corporation)
• Inventors: Ichijo, Hisashi, Katae, Kenichi, Yamanouchi, Torahiko
• Granted Patent: US 7,010,404 B2
• Time in Patent Office: Days
• US Class Current: 701/201
• CPC Class Codes: B66F 9/0755 Position control; Position detectors
• CPC Class Codes: G05D 1/0225 involving docking at a fixed facility, e.g. base station or loading bay parking aids B62D15/027
• CPC Class Codes: G05D 1/0246 using a video camera in combination with image processing means

Abstract

A camera 19 picks up an image of a cargo handling target and acquires image data of a mark affixed to the cargo handling target. An image processing section 66 performs image recognition of the mark and acquires the position and size of the mark in a screen coordinate system. A real coordinate position calculating section 77 acquires the position of the camera 19 in a real coordinate system based on the obtained position and size of the mark. Based on the position of the camera 19, a deviation amount calculating section 78 acquires a deviation amount between the current position of forks and a target position. A cargo handling control section 50 executes automatic positioning control of the forks in such a way that the deviation amount becomes zero.

Claims

1. A position control apparatus for a cargo carrying apparatus on an industrial vehicle, comprising:

a camera for picking up an image of a mark provided on a cargo handling target to acquire data of the image;

image processing means for processing said image data and detecting a position of said mark;

target position determining means for determining a target position to which said cargo carrying apparatus is to be shifted;

deviation amount calculating means for computing a deviation amount of a current position of said cargo carrying apparatus with respect to said target position based on a result of processing said image data by said image processing means;

moving means for moving said cargo carrying apparatus; and

control means for executing a positioning control to position said cargo carrying apparatus with respect to said target position and causing said moving means to move said cargo carrying apparatus in such a way as to eliminate said deviation amount.

2. The position control apparatus according to claim 1, wherein said target position determining means determines said target position based on said detected position of said mark.

3. The position control apparatus according to claim 1 or 2, further comprising operation means, which is operated to cause said control means to start said positioning control.

4. The position control apparatus according to any one of claims 1 to 3, further comprising a display device for displaying the image picked up by said camera.

5. The position control apparatus according to claim 4, further comprising:

drawing means for drawing a target point in the image displayed on said display device; and

target point calculating means for computing a position, based on said target position, in which said target point is to be drawn in such a way that said deviation amount is eliminated when a mark in said image displayed on said display device coincides with said target point.

6. The position control apparatus according to any one of claims 1 to 5, further comprising memory means for storing a template to be used to identify a mark included in said image data, wherein said image processing means identifies the mark in the image data by matching said template with the mark in the image data.

7. The position control apparatus according to claim 6, wherein shapes of said mark and said template are determined in such a way that said template matches with the mark in said image data, irrespective of a distance between said cargo handling target and said camera.

8. The position control apparatus according to any one of claims 1 to 7, further comprising a tilt actuator for tilting said cargo carrying apparatus, wherein said control means causes said tilt actuator to adjust a tilt angle of said cargo carrying apparatus prior to initiation of said positioning control in such a way that a load deposition surface of said cargo carrying apparatus becomes horizontal.

9. The position control apparatus according to any one of claims 1 to 8, wherein based on the image data of said mark, said image processing means identifies a position and size of said mark in a predetermined image coordinate system, the image coordinate system being similar to a real coordinate system where said cargo handling target exists, and said deviation amount calculating means computes said deviation amount based on said identified position and size of said mark.

10. The position control apparatus according to any one of claims 1 to 8, wherein based on the image data of said mark, said image processing means identifies a position and size of said mark in a predetermined image coordinate system, the image coordinate system being similar to a real coordinate system where said cargo handling target exists, and said deviation amount calculating means acquires a current position of the camera with respect to the mark in said real coordinate system based on said identified position and size of said mark and computes said deviation amount based on the acquired current position of the camera.

11. The position control apparatus according to claim 10, wherein said deviation amount computing means uses a relationship between the position of said camera and the position of said cargo carrying apparatus and a relationship between the position of said mark and said target position to compute said deviation amount.

12. The position control apparatus according to any one of claims 1 to 11, further comprising selection means for selecting one of operation modes prepared for said positioning control, wherein said control means executes said positioning control in accordance with the operation mode selected by the selection means.

13. The position control apparatus according to claim 12, wherein said selection means is a manual operation member.

14. The position control apparatus according to claim 12, wherein said selection means automatically selects an operation mode in accordance with a load on said cargo carrying apparatus.

15. The position control apparatus according to any one of claims 12 to 14, wherein said operation modes include a load pickup mode for picking up a load at a predetermined deposition place by means of said cargo carrying apparatus and a load deposition mode for depositing a load on the cargo carrying apparatus at said deposition place.

16. The position control apparatus according to claim 15, wherein said cargo handling target includes a pallet for deposition of a load and a rack on which said pallet is to be placed, said mark is one of a first mark affixed to the pallet and a second mark affixed to the rack, said image processing means detects a position of the first mark when said load pickup mode is selected, and said image processing means detects a position of the second mark when said load deposition mode is selected.

17. The position control apparatus according to claim 16, wherein said target position determining means sets the position of the first mark as said target position when said load pickup mode is selected, and said target position determining means sets a position above the second mark by-a predetermined distance as said target position when said load deposition mode is selected.

18. The position control apparatus according to any one of claims 15 to 17, wherein said control means positions said cargo carrying apparatus in a vertical direction and in a widthwise direction of the vehicle with respect to said target position when said load pickup mode is selected, and said control means positions said cargo carrying apparatus only in the vertical direction with respect to said target position when said load deposition mode is selected.

19. The position control apparatus according to any one of claims 15 to 18, further comprising:

a carriage for supporting said cargo carrying apparatus, said camera being mounted on the carriage; and

a camera lifting actuator for lifting said camera up and down with respect to said carriage,

wherein said camera lifting actuator moves the camera to a level that is substantially the same as or above a lower end of said cargo carrying apparatus when said load pickup mode is selected, and said camera lifting actuator moves the camera below the lower end of said cargo carrying apparatus when said load deposition mode is selected.

20. The position control apparatus according to any one of claims 1 to 18, further comprising:

a carriage having a side shifter movable in a widthwise direction of the vehicle, said cargo carrying apparatus being attached to the side shifter;

a side shift actuator for moving said side shifter; and

a lifting unit for lifting said carriage up and down,

wherein said moving means includes said side shift actuator and said lifting unit.

21. The position control apparatus according to claim 20, wherein said camera is mounted on said side shifter.

22. The position control apparatus according to claim 21, further comprising a camera lifting actuator for lifting said camera up and down with respect to said side shifter.

23. The position control apparatus according to any one of claims 1 to 18, further comprising a lifting unit for supporting and lifting up and down said cargo carrying apparatus, wherein said control means inhibits execution of said positioning control when a height of said cargo carrying apparatus is lower than a predetermined threshold value.

24. The position control apparatus according to any one of claims 1 to 18, further comprising a lifting unit for supporting and lifting up and down said cargo carrying apparatus, wherein said lifting unit has a guide member for guiding said cargo carrying apparatus to move up and down, said lifting unit lifting the cargo carrying apparatus up and down along the guide member when a height of said cargo carrying apparatus is lower than said threshold value, and said lifting unit lifting the guide member up and down while holding the position of the cargo carrying apparatus with respect to the guide member when the height of said cargo carrying apparatus is equal to or higher than said threshold value, wherein the camera is mounted on said guide member.

25. The position control apparatus according to claim 24, wherein said control means inhibits execution of said positioning control when the height of said cargo carrying apparatus is lower than said threshold value.

26. The position control apparatus according to claim 24 or 25, wherein a mounting position of the camera with respect to said guide member is determined in such a way that an image pickup range of said camera is not interference with the cargo carrying apparatus when the height of said cargo carrying apparatus is equal to or greater than said threshold value.

27. The position control apparatus according to claim 26, wherein said camera is positioned below said cargo carrying apparatus when the height of said cargo carrying apparatus is equal to or greater than said threshold value.

28. The position control apparatus according to any one of claims 24 to 27, further comprising:

a side shift actuator for moving said cargo carrying apparatus in a widthwise direction of the vehicle with respect to said guide member, said moving means including said side shift actuator and said lifting unit; and

side shift detecting means for detecting an amount of shifting of said cargo carrying apparatus in the widthwise direction of the vehicle,

wherein said deviation amount calculating means uses the amount of shifting of the cargo carrying apparatus in the widthwise direction of the vehicle to compute said deviation amount.

29. The position control apparatus according to any one of claims 24 to 27, wherein said lifting unit includes a telescopic type mast comprised of a plurality of mast members, wherein the mast members include a guide mast member serving as said guide member, and said guide mast member is positioned at a topmost portion of said mast when the mast is protracted most.

30. The position control apparatus according to claim 29, wherein the height of the cargo carrying apparatus becomes said threshold value when said cargo carrying apparatus is positioned at a topmost end of said guide mast member and said mast is retracted most.

31. The position control apparatus according to claim 29 or 30, wherein said lifting unit further includes a first actuator for lifting said cargo carrying apparatus up and down along said guide mast member and a second actuator for protracting and retracting said mast, said first actuator is driven when the height of the cargo carrying apparatus is lower than said threshold value, and said second actuator is driven when the height of the cargo carrying apparatus is equal to or greater than said threshold value.

32. The position control apparatus according to claim 31, further comprising:

a side shift actuator for moving said cargo carrying apparatus in a widthwise direction of the vehicle with respect to said guide mast member, said moving means including said side shift actuator and said second actuator; and

side shift detecting means for detecting an amount of shifting of said cargo carrying apparatus in the widthwise direction of the vehicle,

wherein said deviation amount computing means uses the amount of shifting of the cargo carrying apparatus in the widthwise direction of the vehicle to compute said deviation amount.

33. The position control apparatus according to any one of claims 29 to 32, wherein said guide mast member is one of a pair of guide mast members, said cargo carrying apparatus is liftable up and down between both guide mast members, and said camera is mounted on a horizontal beam for coupling both guide mast members.

34. A position control method for a cargo carrying apparatus on an industrial vehicle, comprising:

a step of picking up an image of a mark provided on a cargo handling target with a camera to acquire data of the image;

a step of processing said image data and detecting a position of said mark;

a step of determining a target position to which said cargo carrying apparatus is to be shifted;

a step of computing a deviation amount of a current position of said cargo carrying apparatus with respect to said target position based on a result of processing said image data; and

a step of moving said cargo carrying apparatus in such a way as to eliminate said deviation amount.