Method and device for control of AGV

• US 5,801,506 A
• Filed: 02/23/1996
• Issued: 09/01/1998
• Est. Priority Date: 07/22/1993
• Status: Expired due to Fees

• Current Assignee: Apogeum AB
• Original Assignee: Apogeum AB
• Inventors: Netzler, Goran
• Primary Examiner(s): IP, SHIK LUEN PAUL
• Application Number:
  US08/581,538
• Time in Patent Office: 921 Days
• Field of Search: 318/560-696, 318/139, 901/1, 180/167-169, 44/343, 44/273, 44/347, 44/399, 44/608, 44/665, 44/785, 44/274, 44/275, 701/22-28, 364/443, 364/424.01, 364/424.02, 364/424.06
• US Class Current: 318/587
• CPC Class Codes: B66F 9/063 Automatically guided
• CPC Class Codes: G05D 1/0236 in combination with a laser lasers per se H01S
• CPC Class Codes: G05D 1/0246 using a video camera in combination with image processing means

Abstract

A method and a system for controlling an AGV for route selection upon transfer between different spaces within which the AGV is movable. The spaces are not fixedly related to each other with reference to their relative positions and are restricted from each other by the inclusion of area boarder lines. When an AGV is present within a first of the spaces, it detects for the purpose of transfer of the spaces, the relative position of the space by two reference instruments belonging to the second space. Each of the reference instruments is fixedly related to the present space. The AGV will move over the area border lines between the two spaces selecting route depending on calculating relative position.

Claims

1. A method for guiding an AGV over a supporting surface between a stationary work area and a mobile work area, and utilizing a computer-controlled navigation system for determining the relative location of the AGV, said method including the steps of:

a) detecting from the AGV a first set of reference objects including at least two non-identity instruments arranged in predetermined, fixed locations relative to the stationary work area;

b) electronically determining the location of the AGV in the stationary work area relative to the location of said first set of reference objects;

c) detecting from the AGV in the stationary work area a second set of reference objects including at least two non-identity instruments arranged in predetermined, fixed locations relative to the mobile work area;

d) electronically determining the location of the second set of reference objects of the mobile work area relative to the stationary work area; and

e) automatically guiding the AGV from the stationary work area to the mobile work area utilizing location information determined in steps (b) and (d).

2. A method according to claim 1, and comprising the step of mounting the second set of reference objects of the mobile work area on hinges of doors cooperating to open and close access to the mobile work area, such that when the doors are open for loading and unloading, said reference objects are exposed and detectable, and when the doors are closed, said reference objects are concealed and undetectable.

3. A method according to claim 2, and comprising the step of mounting a rotating laser on the AGV for detecting said first and second sets of reference objects.

4. A method according to claim 12, and comprising the steps of:

(f) detecting from the AGV in the mobile work area the first set of reference objects arranged in predetermined, fixed locations relative to the stationary work area;

(g) electronically determining the location of the AGV in the mobile work area relative to the stationary work area; and

(h) automatically guiding the AGV from the mobile work area to the stationary work area utilizing location information determined in step (g).

5. A method for guidance of an AGV for selection of route when passing between different work areas or spaces, within which areas said AGV is mobile, said work areas being separated from each other by means of area boundaries, which at least temporarily are located so as to enable said passing of the AGV, said method utilizing a navigation system for determining the position of the AGV relative to a work area by detecting from the AGV at least two non-identity reference instruments, said method including the following steps:

a) detecting from the AGV a first set of reference objects including at least two instruments having non-identity and having fixed positions relative to a first of said work areas,

b) determining the position of the AGV on said first work area relative to the positions of said first set of reference objects,

c) detecting from the AGV on the first work area a second set of reference objects including at least two instruments having non-identity and having fixed positions relative to a second of said work areas,

d) determining the position of said second work area regarding translation as well as rotation relative to said first work area by said detecting of said second set of reference objects, and

e) guiding the AGV during passing across said area boundaries between said first and second work areas.

6. A vehicle guidance system for guiding an AGV over a supporting surface between a stationary work area and a mobile work area, said guidance system comprising:

(a) a first set of reference objects including at least two non-identity instruments arranged in predetermined, fixed locations relative to the stationary work area;

(b) a second set of reference objects including at least two non-identity instruments arranged in predetermined, fixed locations relative to the mobile work area;

(c) object detection means mounted on the AGV for detecting the presence of said first and second sets of reference objects; and

(d) computer means connected to said object detection means for electronically calculating the location of the AGV relative to said first and second sets of reference objects, and for controlling movement of the AGV over the supporting surface between the stationary work area and the mobile work area.

7. A vehicle guidance system according to claim 6, wherein the mobile work area comprises a mobile load carrier having cooperating doors mounted on hinges for movement between open and closed positions, and wherein said second set of reference objects comprise reflectors located inside said load carrier such that when the doors are open for loading and unloading, said reference objects are exposed and detectable by said object detection means, and when the doors are closed, said reference objects are concealed and undetectable by said object detection means.

8. A vehicle guidance system according to claim 6, wherein said object detection means comprises a rotating laser.