System for loading and unloading trailers using automatic guided vehicles

• US 4,950,118 A
• Filed: 03/22/1989
• Issued: 08/21/1990
• Est. Priority Date: 03/22/1989
• Status: Expired due to Fees

• Current Assignee: FMC Corporation
• Original Assignee: Caterpillar Incorporated
• Inventors: Mueller, William R., Nestoff, Richard A., Wible, John E.
• Primary Examiner(s): Basinger, Sherman D.
• Application Number:
  US07/327,196
• Time in Patent Office: 517 Days
• Field of Search: 414/273, 414/274, 414/275, 414/398, 414/340, 414/343, 414/345, 180/167, 180/169
• US Class Current: 414/274
• CPC Class Codes: G05D 1/0234 using optical markers or beacons optical beacons per se G01S1/70
• CPC Class Codes: G05D 1/0242 using non-visible light signals, e.g. IR or UV signals
• CPC Class Codes: G05D 1/0265 using buried wires
• CPC Class Codes: G06Q 10/08 Logistics, e.g. warehousing, loading or distribution; Inventory or stock management

Abstract

A system using free ranging automatic guided vehicles (AGVs) for loading and unloading material from a number of trailers is provided. The system employs a plurality of sensors for monitoring both pedestrian, operator driven vehicles and other AGV traffic, and for ensuring that the trailers are parked in position and ready for loading and unloading. The system further includes signals for controlling traffic and a plurality of trailer mounted targets for AGV navigation. During an operation cycle full containers are unloaded from a first trailer and empty containers are loaded on a second trailer.

Claims

1. A system for loading and unloading a mobile structure with at least one automatic guided vehicle (AGV), said system comprising:

means for detecting said mobile structure being in position and arranged and oriented for loading and unloading, and for delivering a signal in response to said mobile structure being in position and arranged and oriented for loading and unloading;

means for navigating said AGV inside said mobile structure;

means for monitoring traffic and delivering a signal in response to unauthorized traffic being present; and

means for receiving said traffic monitoring signal and halting said AGV in response to receiving said traffic monitoring signal.

2. A system for loading material into a second trailer, unloading material from a first trailer and transferring said material between at least one pick-up and drop-off location spaced from said trailers, said first and second trailers being parked at first and second docks, respectively, of a loading dock area and said loading and unloading being performed by at least one automatic guided vehicle (AGV), said system comprising:

means for detecting said first trailer being parked at said first dock and responsively delivering a first docking signal;

means for detecting said second trailer being parked at said second dock and responsively delivering a second docking signal;

means for monitoring traffic and delivering a traffic monitoring signal in response to traffic entering the loading dock area;

means for controlling the flow of traffic entering said area;

means for detecting the presence of material at said pick-up and drop-off location and delivering a material signal in response to said material being present;

controller means for receiving said first and second docking signals, said material signal, and said traffic monitoring signal, accounting for the amount of material in said first and second trailers and directing said AGV to transfer material in response to said first and second signals being received, said traffic monitoring signal being absent and said material signal being received.

3. A system for loading material into a second trailer, unloading material from a first trailer and transferring said material between the trailers and a plurality of conveyors, said first and second trailers being parked at first and second docks respectively, said docks having doors, said material handling system using an automatic guided vehicle (AGV), and said AGV navigating by sighting a plurality of unique landmarks, said system comprising:

means for sensing said first trailer being parked at said first dock and said first trailer door being open and responsively delivering a first trailer signal;

means for sensing said second trailer being parked at said second dock and said second trailer door being open and responsively delivering a first trailer signal;

means for monitoring traffic and delivering a traffic monitoring signal in response to traffic entering the loading dock area;

means for controlling the flow of traffic entering said area;

means for detecting the absence and presence of material on said conveyors and delivering a material signal in response to said material being present;

controller means for receiving said first and second docking signals, said material signal, and said traffic monitoring signal, accounting for the amount of material in said first and second trailers and directing said AGV to pick up and deposit material in response to said first and second signals being received, said traffic monitoring signal being absent and said material signal being received.

4. The system, as set forth in claim 3, wherein said traffic monitoring means monitors all pedestrian, operator driven vehicle and automatic guided vehicle traffic and controls said automatic guided vehicle traffic.

5. The system, as set forth in claim 4, wherein said controller means halts said AGV in response to said traffic monitoring means detecting unauthorized entry into said trailers.

6. The system, as set forth in claim 5, wherein said traffic monitoring means includes means for signaling traffic to halt other than AGV traffic.

7. The system, as set forth in claim 6, wherein said traffic monitoring means includes at least one optical sensor.

8. The system, as set forth in claim 6, wherein said traffic controlling means includes at least one traffic light signal.

9. The system, as set forth in claim 3, wherein said controller means includes means for navigating said AGV and reorienting the direction of said AGV travel inside said trailers.

10. The system, as set forth in claim 9, wherein said first and second trailers include a plurality of unique landmarks being adapted for AGV navigation inside said trailers.

11. The system, as set forth in claim 3, wherein said material are housed in containers, and said AGV unloads full containers from said first trailer, and loads empty containers into said second trailer.

12. The system, as set forth in claim 11, wherein said plurality of conveyors includes first and second conveyors and wherein said AGV deposits full containers onto one of the first and second conveyors, and picks up empty containers from said other of said first and second conveyors.

13. The system, as set forth in claim 3, wherein said material is housed in racks, and said AGV unloads full racks from said first trailer, and loads empty racks into said second trailer.

14. The system, as set forth in claim 13, wherein said plurality of conveyors includes first and second conveyors, said AGV depositing full racks onto one of the first and second conveyors, and picking up empty racks from the other of said first and second conveyors.

15. The system, as set forth in claim 3, wherein each of said AGVs further include a fork lift.

16. The system, as set forth in claim 3, wherein an initial condition calls for said first trailer containing a fixed amount of material, and said second trailer being empty.

17. The system, as set forth in claim 16, wherein said controller means decrements from said fixed amount as material is unloaded from said first trailer, and increments from zero as material is loaded into said second trailer.

18. A method for loading material into a second trailer and unloading material from a first trailer and transferring said material to and from at least one pick-up and drop-off location outside of said first and second trailers, said first and second trailers being parked at first and second docks, respectively, said loading and unloading being performed by at least one automatic guided vehicle (AGV), and said AGV navigating by sighting a plurality of unique landmarks, said method comprising the steps of:

detecting said first trailer being parked at said first dock;

detecting said second trailer being parked at said second dock;

monitoring and controlling traffic;

detecting absence and presence of material at said pick-up and drop-off location;

accounting for the amount of material in said first and second trailers; and

directing said AGV to transfer material in response to said detecting means, monitoring means, and accounting means.

19. A method for loading a number of containers into a second trailer and unloading a number of containers from a first trailer and transferring said containers to and from at least two conveyors, said first and second trailers being parked at first and second docks respectively, said docks having doors, said material handling using at least one automatic guided vehicle (AGV), and said AGV navigating by sighting a plurality of unique landmarks, comprising the steps of:

sensing said first and second trailers being parked in position;

sensing and monitoring traffic conditions continuously;

directing said AGV to unload containers from said first trailer;

detecting unauthorized entry of said first trailer continuously;

entering said first trailer and picking up a container from said first trailer;

decrementing and recording the number of containers left in said trailer;

detecting absence of containers on said first conveyor;

directing said AGV to deposit the container onto said first conveyor;

detecting presence of a container on said second conveyor;

directing said AGV to pick up the container from said second conveyor;

directing said AGV to load said container onto said second trailer;

detecting unauthorized entry of said second trailer continuously;

entering said second trailer and depositing the container into said second trailer; and

incrementing and recording the number of containers in said second trailer.

20. A system for loading and unloading a plurality of rows of containers in a mobile structure having spaced apart walls and being docked at a loading dock of a facility, said system comprising:

a plurality of targets mounted at spaced apart locations on the walls of the mobile structure and lining said walls;

a free ranging automatic guide vehicle adapted to enter said mobile structure, sight the targets in the mobile structure which are visible and unblocked by the containers, and realign itself with respect to the sighted targets irrespective of the position of the mobile structure at the loading dock;

means for detecting said mobile structure being at said loading dock and ready for entry by said automatic guided vehicle and delivering a signal in response to said mobile structure being present and ready for entry;

means for receiving said signal and commanding said automatic guided vehicle to enter said mobile structure.