AUTOMATIC TRANSPORT LOADING SYSTEM AND METHOD

• US 20070269299A1
• Filed: 06/21/2007
• Published: 11/22/2007
• Est. Priority Date: 05/03/2004
• Status: Active Grant

• Current Assignee: Jervis B Webb Company (Daifuku Company Limited)
• Original Assignee: Jervis B Webb Company (Daifuku Company Limited)
• Inventors: Ross, Wayne, Chilson, Gerald
• Granted Patent: US 8,192,137 B2
• Time in Patent Office: Days
• US Class Current: 414/347
• CPC Class Codes: B60L 15/2036 Electric differentials, e.g. for supporting steering vehicles
• CPC Class Codes: B60L 15/38 with automatic control
• CPC Class Codes: B60L 2200/26 Rail vehicles
• CPC Class Codes: B60L 2200/42 Fork lift trucks
• CPC Class Codes: B66F 9/063 Automatically guided
• CPC Class Codes: B66F 9/0755 Position control; Position detectors
• CPC Class Codes: B66F 9/085 Multiple forks, i.e. more than one pair mounted on a single mast or with more than one mast
• CPC Class Codes: G05D 1/024 in combination with a laser lasers per se H01S
• CPC Class Codes: G05D 1/027 comprising intertial navigation means, e.g. azimuth detector inertial navigation G01C21/16; inertial navigation combined with non-inertial navigation instruments G01C21/165
• CPC Class Codes: G05D 1/0272 comprising means for registering the travel distance, e.g. revolutions of wheels measuring distance traversed on the ground by vehicles, e.g. using odometers G01C22/00
• CPC Class Codes: Y02P 90/60 Electric or hybrid propulsion means for production processes
• CPC Class Codes: Y02T 10/72 Electric energy management in electromobility

Abstract

A method and system for automatically loading and unloading a transport is disclosed. A first guidance system follows a travel path to a position near the transport and then a sensor profiles a transport so that a transport path is determined for an AGV to follow into the transport to place a load and for exiting the transport upon placement of the load.

Claims

1. A method for loading a transport with an automatic guided vehicle (AGV) comprising:

engaging a load with the AGV;

guiding the AGV with a guidance system to a position A and wherein the position A is located outside of the transport;

determining a transport path for depositing the load at an intended load position on the transport;

guiding the AGV along the determined transport path with the guidance system to the intended load position; and

depositing the load onto the transport at the intended load position.

2. The method of claim 1 further including a step of guiding the AGV along the determined transport path from the intended load position to position A after said step of depositing the load.

3. The method of claim 1 further including the step of switching from the determined transport path to a system path at position A, after said step of guiding the AGV along the determined transport path from the intended load position to position A.

4. The method of claim 1 wherein said step of determining a transport path includes the steps of:

sensing side walls of the transport; and

determining a path between the side walls.

5. The method of claim 4 wherein said step of sensing the sidewalls is performed by a laser sensor.

6. The method of claim 4 wherein said step of sensing the sidewalls is performed by a sensor remote from the AGV.

7. The method of claim 4 wherein said step of sensing the sidewalls is performed by a sensor located on the AGV.

8. The method of claim 1 further including the step of positioning the AGV along the transport path, between said steps of determining a transport path, and guiding the AGV along the determined transport path.

9. The method of claim 1 wherein the guidance system comprises an inertial guidance system.

10. The method of claim 1 wherein said step of depositing the load further includes the steps of:

lowering the load before reaching the load position;

pushing the load along the floor of the transport to the intended load position;

measuring the pressure required to push the load to the intended load position; and

stop pushing the load when the measured pressure exceeds a set value.

11. The method of claim 10 wherein the step of measuring the pressure is performed by monitoring the current supplied to a motor on the AGV.

12. The method of claim 1 wherein the step of guiding the AGV to position A further includes the step of rotating the AGV 180 degrees before reaching position A.

13. The method of claim 1 wherein said step determining a transport path also includes the step of sensing the sidewalls of the transport, including the ends of the side walls defining the opening into the transport through which the AGV passes.

14. The method of claim 13 further including the step of determining the skew and offset of the transport.

15. The method of claim 13 further including the step of providing information from the sensor regarding the sidewalls of the transport to a central controller and wherein the central controller calculates a transport path.

16. The method of claim 15 further including the step of communicating the calculated transport path to the guidance system on the AGV.

17. The method of claim 1 further including the step of calibrating the actual position of the AGV after said step of guiding the AGV to a position A.

18. The method of claim 17 wherein said step of calibration further includes the step of gathering data of a fixed object in proximity to the transport and comparing the location actual location of the AGV relative to the fixed object to the expected location of the AGV relative to the fixed object.

19. The method of claim 18 further including the step of updating the guidance system with the actual location of the AGV in the system.

20. A method for loading a transport with an automatic guided vehicle (AGV) comprising:

engaging a load with the AGV;

guiding the AGV with an inertial guidance system to a position A;

determining a transport path from position A to an intended load position on the transport;

aligning the AGV with the determined transport path

guiding the AGV along the determined transport path using the inertial guidance system from position A to the intended load position;

depositing the load; and

guiding the AGV along the transport path using the inertial guidance system from the intended load position to position A.

21. The method of claim 20 wherein said step of determining a transport path from position A further includes the steps of:

sensing the side walls of the transport; and

determining the best path for the AGV to follow between the side walls of the transport.

22. The method of claim 21 wherein said step of sensing the side walls of the transport also includes the step of determining the location of the opening of the transport defined by the side walls, through which the AGV must travel.

23. The method of claim 20 wherein said step of determining a transport path is performed as the AGV is being guided to position A.

24. The method of claim 20 wherein said step of determining a transport path is performed when the AGV is at approximately position A.

25. The method of claim 20 further including the step of calibrating the location of the AGV during said step of determining a transport path.

26. A method for loading a transport with automatic guided vehicles (AGVs) using an AGV system having a central controller and an AGV controller on each AGV, said method comprising:

directing the AGV to engage a load and travel along a system travel path to a position A, wherein position A is located near a loading bay door;

sensing the location of sidewalls of the transport located at a loading bay door near position A;

determining a transport path for the AGV to follow into the transport;

adding the transport path to the system travel paths in the central controller;

guiding the AGV along the transport path to a determined load position; and

depositing the load.

27. The method of claim 26 further including the steps of:

guiding the AGV from the determined load position to position A, after depositing the load;

updating the AGV controller with a new system travel path from the central controller; and

switching from the transport travel path to the new system travel path near position A.

28. The method of claim 26 further including the steps of:

updating a second AGV controller on a second AGV with the determined transport path;

guiding the AGV to position A along a system travel path;

switching from the system travel path to the determined transport path near position A; and

guiding the AGV from position A along the determined transport path to a determined load position.

29. The method of claim 26 wherein said step of determining a transport path for the AGV further includes the steps of:

uploading to the central controller the information received from a sensor during said step of sensing the side walls of the transport; and

determining the optimal AGV travel path between the sidewalls of the transport.

30. The method of claim 26 further including the steps of:

directing a second AGV along a system path to position A;

sensing the sidewalls of the transport with a sensor on the second AGV;

determining a second transport path;

determining an updated transport path that averages the information received from said step of sensing the sidewalls and the information received from said step of sensing the sidewalls with a sensor on the second AGV; and

guiding the second AGV along the updated transport path from position A.

31. The method of claim 26 wherein said step of sensing the transport side walls is performed by a sensor on the AGV.

32. The method of claim 26 further including the step of removing the transport path from the central controller upon determining that all loads to be placed on the transport have been placed on the transport.

33. A method of unloading a transport with an automatic guided vehicle comprising:

directing an AGV to a position A sensing the sidewalls of the transport and approximate location of a first load within the transport with a sensor and providing information received from the sensor regarding the location of the sidewalls to a controller;

determining a transport path with the controller;

directing the AGV along the determined transport path to the first load;

engaging the first load;

directing the AGV along the determined transport path to position A;

updating the AGV with a system travel path;

switching to the system travel path when the AGV reaches approximately position A; and

directing the AGV along the system travel path.

34. The method of claim 33 further including the steps of:

directing an AGV to a position A;

sensing the sidewalls of the transport and approximate location of a next load within the transport with a sensor and providing information received from the sensor regarding the location of the sidewalls of the sensor to a controller;

determining an updated transport path with the controller by averaging the information received from a sensor each time the step of sensing the sidewalls is performed;

directing the AGV along the updated transport path to the next load;

engaging the next load;

directing the AGV along the updated transport path to position A;

updating the AGV with a system travel path;

switching to the system travel path when the AGV reaches position A; and

directing the AGV along the system travel path.