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US4940925A
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US
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Closed-loop navigation system for mobile robots
Assignee: Texas Instruments Inc
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Filing: 1988-10-31
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Granted: 1990-07-10
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Expires: 2008-10-31
Abstract
Abstract A visual navigation system provides absolute position information to multiple automatically guided vehicles (AGVs) such as mobile robots. The beacon-equipped AGVs emit light visible to overhead television cameras. The beacons are arranged and controlled so that the vision systems can acquire, measure, and report the locations of multiple AGVs. The system controller incorporates a programmable "factory map", or knowledge base, of allowable paths of travel for the AGVs, which navigate by dead reckoning with periodic position updates from the visual navigation system. The visual navigation system notifies the autonomous AGVs and the system controller when an AGV strays from its command path. The combination of computer controls in the elements of the system provides the means to stop and to recover straying AGVs. The navigation system visually monitors normal AGV travel, off-course corrections, "lost" AGV searches, and recovery. Thus, it provides closed-loop, servo-like operation.
Inventors
- 👤 Martin A. Wand
- 👤 Anh V. Ho
- 👤 Chuan-Fu Lin
- 👤 Phen-Lan Huang
- 👤 John P. Williston
- 👤 Haradon J. Rice
- 👤 Thomas J. Doty
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 10:59
CPC Classifications
G; G05; G05D; G05D1/00; G05D1/02; G05D1/021; G05D1/0287; G05D1/0291; G05D1/0297; G05D1/0231; G05D1/0246; G05D1/0276; G05D1/028; G05D1/0282
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
83 words
A visual navigation system, comprising: at least one AGV; a plurality of nodes; a camera associated with each node for viewing said AGV; and a navigation system for generating the position of said AGV from an image formed by one of said cameras; wherein said navigation system has knowledge of an AGV route map and a schedule of planned movements for said AGV, and uses such information to predict and select the camera in whose field of view said AGV can be found.
Claim 2
Dependent Claim
83 words
A visual navigation system, comprising: at least one AGV; a plurality of nodes; a camera associated with each node for viewing said AGV; and a navigation system for generating the position of said AGV from an image formed by one of said cameras; wherein said navigation system has knowledge of an AGV route map and a schedule of planned movements for said AGV, and uses such information to predict and select the camera in whose field of view said AGV can be found.
Claim 3
Dependent Claim
28 words
The visual navigation system of claim 1, further comprising: a uniquely identifiable visual pattern associated with each AGV for unique identification of each AGV by said navigation system.
Claim 4
Dependent Claim
20 words
The visual navigation system of claim 2, wherein said visual pattern comprises: a plurality of lights mounted on each AGV.
Claim 5
Dependent Claim
28 words
The navigation system of claim 1, wherein: said navigation system tracks AGV motion near a given node always using the same camera which is associated with that node.
Claim 6
Independent Claim
105 words
A method of navigating AGVs, comprising: (a) assigning a plurality of nodes to locations along a route for an AGV such that each node is assigned to a unique location; (b) positioning a camera near each node for viewing an AGV at or near that node; (c) using an AGV route map and a schedule of planned movements for said AGV to predict and select the camera in whose field of view said AGV can be found; (d) using said selected camera to form an image of an identifiable portion of said AGV; and (e) determining the X-Y position of said AGV from said image.
Claim 7
Independent Claim
105 words
A method of navigating AGVs, comprising: (a) assigning a plurality of nodes to locations along a route for an AGV such that each node is assigned to a unique location; (b) positioning a camera near each node for viewing an AGV at or near that node; (c) using an AGV route map and a schedule of planned movements for said AGV to predict and select the camera in whose field of view said AGV can be found; (d) using said selected camera to form an image of an identifiable portion of said AGV; and (e) determining the X-Y position of said AGV from said image.
Claim 8
Dependent Claim
16 words
The method of claim 5, wherein: steps (c) and (e) are carried out by a computer.
Claim 9
Dependent Claim
17 words
The method of claim 6, further comprising: storing said route map and said schedule in computer memory.
Claim 10
Dependent Claim
29 words
The method of claim 5, further comprising: associating a unique camera with a node; and always using that unique camera when viewing said AGV at or near that node.
Claim 11
Dependent Claim
24 words
The method of claim 6, further comprising: storing a digitized representation of the field of view of said selected camera in random access memory.
Claim 12
Dependent Claim
24 words
The method of claim 9, further comprising: forming a window about said AGV; and searching only the data within said window for said image.
References Cited (Backward Citations)
JPS5764818A
Cited
JPS6089213A
Cited
JPS613210A
Cited
JPS61134812A
Cited
US4773018A
Cited
US4750123A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1993-07-09 | 1994-01-08 | 1994-07-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-07-09 | 1998-01-08 | 1998-07-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-07-09 | 2002-01-08 | 2002-07-10 | $7700.00 | Window Closed / Lapsed |