Automatic guided vehicle system

• US 4,817,000 A
• Filed: 03/10/1986
• Issued: 03/28/1989
• Est. Priority Date: 03/10/1986
• Status: Expired due to Fees

• Current Assignee: SI Handling Systems, Inc. (Paragon Technologies Incorporated)
• Original Assignee: SI Handling Systems, Inc. (Paragon Technologies Incorporated)
• Inventors: Eberhardt, Nikolai
• Primary Examiner(s): Lall, Parshotam S.
• Assistant Examiner(s): Black, Thomas G.
• Application Number:
  US06/838,088
• Time in Patent Office: 1,114 Days
• Field of Search: 364/424, 364/460, 364/443, 364/513, 180/167, 180/168, 180/169, 340/942
• US Class Current: 701/200
• CPC Class Codes: G05D 1/0234 using optical markers or beacons optical beacons per se G01S1/70
• 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: G05D 1/028 using a RF signal

Abstract

Automatic guided vehicle system for guiding a driverless vehicle over a predetermined path of travel without any tracks, wires or the like. The vehicle is provided with an active optical navigation section for determining vehicle position and bearing by scanning plural beacons distributed within the zone of travel of the vehicle, a passive ground navigation section including a gyrocompass for measuring changes in bearing of the vehicle and a wheel encoder for measuring distance traveled by the vehicle'"'"'s steering wheel. Memory onboard the vehicle contains a series of path vectors which define a predetermined path of travel for the vehicle. The ground navigation section updates vehicle position and bearing as determined by the optical navigation section. A programmed onboard computer includes driver software for generating steering data so as to guide the vehicle over a corrective arc path from its position and bearing as determined by the navigation sections to the desired position and bearing as indicated by a stored path vector.

Claims

1. Automatic guided vehicle system for guiding a driverless vehicle within a predetermined zone divisible into coordinate positions, comprising:

driverless vehicle provided with a steering mechanism and a drive controller for controlling the steering mechanism so as to guide the vehicle over arc path segments within the zone,

plural beacons distributed within the zone outboard the driverless vehicle,

memory onboard the vehicle for storing a series of coordinate positions representing the positions of the beacons and for storing a series of path vectors each comprising position and bearing data, said vectors together representing a predetermined path of travel for the vehicle,

first navigation section onboard the vehicle including means for optically scanning said beacons and means for generating data signals indicating the position and bearing of the vehicle based on an optical scan of the beacons,

second navigation section onboard the vehicle including means for generatiang data signals indicating changes in the vehicle position and bearing as indicated by said first navigation section data signals, and

driver means onboard the vehicle and responsive to said data signals generated by said first and second navigation sections and to said stored path vectors for causing said drive controller to control said steering mechanism such that said vehicle follows said predetermined path of travel.

2. Automatic guided vehicle system according to claim 1 wherein said driver means includes means for causing said drive controller to control said steering mechanism such that said vehicle follows said predetermined path of travel in forward or reverse directions.

3. Automatic guided vehicle system according to claim 1 wherein said driver means includes means for calculating a corrective arc path for said vehicle based on the data generated by said first and second navigation sections and the position and bearing data indicated by said stored path vectors, and means for causing said drive controller to control said steering mechanism such that said vehicle follows said corrective arc path.

4. Automatic guided vehicle system according to claim 3 wherein said corrective arc path comprises a pair of arc segments.

5. Automatic guided vehicle system according to claim 1 wherein said first navigation section includes means for measuring the ranges between the vehicle and at least three of said beacons based on an optical scan of the beacons.

6. Apparatus according to claim 1 wherein said means for optically scanning said beacons includes a laser beam and means for rotating said laser beam over substantially 360°

azimuth.

7. Automatic guided vehicle system according to claim 1 wherein said second navigation section includes means comprising a gyrocompass for measuring change in bearing of the vehicle and means including a wheel encoder for measuring distance traveled by the vehicle, and wherein said second navigation section means for generating data signals is responsive to the measurements of bearing change and distance traveled.

8. Automatic guided vehicle system for guiding a driverless vehicle within a predetermined zone divisible into coordinate positions, comprising:

driverless vehicle provided with a steering mechanism and a drive controller for controlling the steering mechanism so as to guide the vehicle over arc path segments within the zone,

plural beacons distributed within the zone outboard the vehicle,

memory on board the vehicle for storing a series of coordinate positions representing the positions of said beacons and for storing a series of path vectors each comprising position and bearing data, said vectors together representing a predetermined path of travel for the vehicle,

navigation means on board the vehicle for generating data signals indicating vehicle position and bearing by electro-optically measuring the ranges of the vehicle with respect to a preselected number of said beacons, said navigation means including a gyrocompass for measuring change in bearing of the vehicle and a wheel encoder for measuring distance traveled by said steering mechanism, and wherein said data signals are generated based in part on the measured bearing change and travel distance, and

driver means on board the vehicle for generating steering commands for said drive controller based on said data signals and on said stored path vectors so as to cause said vehicle to follow said predetermined path of travel.

9. Automatic guided vehicle system according to claim 8 wherein said driver means includes means for determining whether said vehicle is within a predetermined range of a stored path vector, and means for calculating a corrective arc path for said vehicle based on said data signals and said stored path vector.

10. Automatic guided vehicle system according to claim 9 wherein said corrective path comprises a pair of arc segments.