GUIDANCE SYSTEM FOR AN AUTOMATED GUIDED-VEHICLE

• US 20010001843A1
• Filed: 03/09/1998
• Published: 05/24/2001
• Est. Priority Date: 03/09/1998
• Status: Active Grant

• Current Assignee: Jervis B Webb Company (Daifuku Company Limited)
• Original Assignee: Jervis B Webb Company (Daifuku Company Limited)
• Inventors: DRENTH, RONALD R., ALOFS, CORNELL W.
• Granted Patent: US 6,272,406 B2
• Time in Patent Office: Days
• US Class Current: 701/24
• CPC Class Codes: G05D 1/0229 in combination with fixed guiding means
• CPC Class Codes: G05D 1/0236 in combination with a laser lasers per se H01S

Abstract

A guidance system for guiding an automated guided vehicle along a pathway is disclosed which includes rails for holding the AGV to the generally straight portions of the pathway and a non-rail guidance system for directing the AGV from the end of a first rail segment to the beginning of another. The rails provide the necessary level of control to allow an unmanned vehicle to move at high speeds while the non-rail guidance system eliminates the need for the rail switches that would otherwise be needed to shift a rail guided vehicle from one rail portion to another.

Claims

1. A guidance system for guiding an AGV comprising:

a plurality of noncontiguous rail segments;

a steering mechanism for guiding the AGV along said rail segments; and

,

an electronic controller for guiding said AGV between said rail segments.

2. The guidance system of

claim 1

wherein said electronic controller includes stored directions for guiding said AGV between rail segments.

3. The guidance system of

claim 1

wherein said electronic controller receives directions for guiding said AGV between rail segments from a system controller.

4. The guidance system of

claim 1

wherein said steering mechanism comprises guide roller means for engaging said plurality of rail segments.

5. The guidance system of

claim 4

wherein said guide roller means comprises a pair of guide rollers having mutually parallel axes perpendicular to said steering mechanism.

6. An AGV system for transporting objects between different locations over a pathway comprising at least one generally straight path section and at least one curved path section comprising:

at least one AGV;

a linear guidance rail segment having a beginning and an end disposed along said at least one generally straight path section;

a mechanical controller for causing said AGV to follow said guidance rail segment; and

,

an electronic controller for directing said AGV from the end of one of said guidance rails to the beginning of another one of said guidance rails.

7. The AGV system of

claim 6

wherein said linear guidance rail segment comprises a first end and a second end and at least one machine-readable informational marker.

8. The AGV of

claim 7

wherein said mechanical controller comprises a steering mechanism in contact with said rail segment.

9. The AGV of

claim 8

wherein said electronic controller includes a microprocessor comprising a memory means for storing a description of said pathway.

10. The AGV of

claim 9

wherein said information includes the lengths of said linear guidance rail segments and the shape of the shape of said at least one curved path section.

11. The AGV of

claim 8

wherein said electronic controller comprises an onboard controller aboard said at least one AGV and a central controller in communication with said onboard controllers for directing said at least one AGV to a destination.

12. A method for switching an automatic rail-guided vehicle from a first rail section having first and second ends to a second rail section having first and second ends comprising the steps of:

providing the rail guided vehicle with an off-rail navigation system;

running said vehicle along said first rail section and off the second end of the first rail section;

navigating said vehicle from the second end of said first rail section to the first end of said second rail section using said off-rail navigation system; and

,

running said vehicle onto said first end of said second rail section and along said second rail section.

13. The method of

claim 12

including the additional steps of

providing said first rail with a machine-readable informational marker;

reading the information contained in said informational marker into said off-rail navigation system; and

,

navigating said vehicle in accordance with the information communicated by said marker.

14. The method of

claim 12

wherein the step of running said vehicle along said first rail section includes the additional steps of sensing the approach of the end of said first rail section and decelerating.

15. The method of

claim 14

wherein the step of decelerating comprises the steps of determining the path to be followed between the end of said first rail section and the beginning of said second rail section, calculating a safe speed for traveling between said end and said beginning, and decelerating to said safe speed.

16. The method of

claim 14

wherein the step of sensing the approach of the end of said first rail section comprises the step of determining whether said vehicle must execute a turn at said end.

17. The method of

claim 16

wherein said vehicle includes steering means for following said rail sections and wherein said steering means locks to keep said vehicle on a linear path when said vehicle is not required to execute a turn at said end.

18. A method for running an AGV from a first point to a second point over a path including linear and non-linear portions comprising the steps of:

providing a first linear rail segment including first and second informational markers;

providing a non-collinear second linear rail segment spaced apart from said first rail segment and including first and second informational markers;

providing an AGV having a steering arm for following said rail segments to guide said AGV along said rail segments and an electronic navigational system for guiding said AGV when no rail segments are available;

accelerating said AGV to a high speed along said first rail segment;

reading one of said informational markers to detect the end of said first rail segment and decelerating said AGV to a low speed;

running said AGV off said first rail segment;

directing said AGV over a non-linear path from said first rail segment to said second rail segment at said low speed;

engaging said second rail segment with said steering arm; and

,

accelerating said AGV to said high speed along said second rail segment.