Downward compatible AGV system and methods

• US 5,341,130 A
• Filed: 06/26/1992
• Issued: 08/23/1994
• Est. Priority Date: 12/03/1990
• Status: Expired due to Fees

• Current Assignee: HK Systems Incorporated (KION GROUP AG)
• Original Assignee: Eaton-Kenway Incorporated
• Inventors: Zuercher, Joseph, Whatcott, Gary L., Yardley, James V., Schutten, Herman P., Petersen, John A. M., Mottes, Rick S., Guest, Vaughn W., Bloomfield, Bryan A., Christensen, L. Bruce, Forman, Robert K.
• Primary Examiner(s): Yusko, Donald J.
• Assistant Examiner(s): Horabik, Michael
• Application Number:
  US07/908,691
• Time in Patent Office: 788 Days
• Field of Search: 340/825.06, 180/168, 318/587, 364/424.02
• US Class Current: 340/3.1
• CPC Class Codes: G01C 19/56 Turn-sensitive devices using vibrating masses, e.g. vibratory angular rate sensors based on Coriolis forces
• CPC Class Codes: G05D 1/0261 using magnetic plots
• CPC Class Codes: G05D 1/0265 using buried wires
• 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 1/0274 using mapping information stored in a memory device navigation using map-matching G01C21/30

Abstract

An automated guided vehicle (AGV) control system which is downward compatible with existing guidewire systems providing both guidewire navigation and communication and autonomous navigation and guidance and wireless communication between a central controller and each vehicle. Vehicle steering and control includes autonomous guidance and navigation of the vehicle over paths marked by update markers which may be spaced well apart, such as fifty feet. The control system employs high frequency two-way data transmission and reception capability over the guidewires and via wireless communications. The same data rates and message formats are used in both guidewire and wireless communications systems. Substantially the same communications electronics are used for the central controller and each vehicle. Novel navigation and guidance algorithms are used to select and calculate a non-linear path to each next vehicle waypoint when the vehicle is operating in the autonomous mode. The non-linear path orginates with an initial direction equal to the heading of the vehicle as it enters the path and a waypoint heading defined as part of the message received from the central control system which plans and controls travel of each vehicle in the system.

Claims

1. A downwardly compatible automated guided vehicle system wherein automatic guided vehicles at different times traverse a plurality of types of guidepaths, said system comprising:

at least one guidepath marked only by a guidewire;

at least one other guidepath marked only by widely dispersed update markers;

at least one automated guided vehicle comprising means for navigating and guiding over the guidewire marked guidepath and for navigating and guiding over the guidepath marked only by update markers and which at different times traverses said at least one guidepath marked only by a guidewire and said at least one other guidepath of marked only by update markers of said plurality of guidepaths;

central means for automatically planning and controlling activity of the at least one automated guided vehicle;

means for sending and receiving two-way communications comprising the same type and rate of data presentation, independent of the type of guidepath traveled by the vehicle, between the central means and the at least one automated guided vehicle.

2. A downwardly compatible automated guided vehicle system according to claim 1 further comprising at least one other automated guided vehicle which traverses only one type of guidepath.

3. A downwardly compatible automated guided vehicle system according to claim 2 wherein the at least one other guided vehicle comprises a vehicle which only traverses the at least one guidepath marked by a guidewire.

4. A downwardly compatible automated guided vehicle system according to claim 1 wherein the at least one automated guided vehicle comprises at least two automated guided vehicles.

5. A downwardly compatible automated guided vehicle system according to claim 4 wherein the central means and the at least two automated guided vehicles comprise means for communicating among the central means and the at least two automated guided vehicles.

6. A downwardly compatible automated guided vehicle system according to claim 1 wherein the at least one automatic guided vehicle comprises two-way wireless vehicle communications means.

7. A downwardly compatible automated guided vehicle system according to claim 1 wherein the communicating means comprise two-way guidewire communication means and two-way wireless communication means.

8. A downwardly compatible automated guided vehicle system according to claim 1 wherein the communicating means comprise guidewire and wireless transceiving means in communication with the at least one vehicle, the transceiving means comprising means one set of which is located on said vehicle and one set which is at said center means for communicating the same control information with compatible characteristics along the guidewire and via wireless transmission between the central means and the at least one vehicle.

9. A downwardly compatible automated guided vehicle system according to claim 8 wherein the means for communicating the same control information comprise means for cognitively transmitting and receiving data along the guidewire and via the wireless transmission at substantially the same high baud rate.

10. A downwardly compatible automated guided vehicle system according to claim 9 wherein the data transmitting and receiving means comprise means for sending useable data at rates up to 9600 baud.

11. A downwardly compatible automated guided vehicle system according to claim 10 wherein the sending means has a bandpass frequency in the range of 3000 Hertz.

12. A downwardly compatible automated guided vehicle system according to claim 8 wherein the central means comprise means for receiving, automatically processing, prioritizing and delaying processing of some signals in favor of other signals.

13. A downwardly compatible automated guided vehicle system according to claim 1 wherein the central means comprise means for selectively issuing communication signals comprising guidewire signals comprising vehicle motion commands and wireless signals comprising vehicle motion commands to each at least one vehicle.

14. A downwardly compatible automated guided vehicle system according to claim 13 wherein the at least one automated guided vehicle comprises means for receiving guidewire and wireless signals whereby motion commands are received for processing at the at least one vehicle.

15. A downwardly compatible automated guided vehicle system according to claim 1 wherein the at least one vehicle comprises means for receiving target bearing and location data from the central means and means for adjusting vehicle bearing in order to drive the at least one automated guided vehicle toward a target.

16. A downwardly compatible automated guided vehicle system according to claim 1 wherein the at least one automated guided vehicle comprises means for accessing floor coordinates means whereby an estimate of each current location of the at least one automated guided vehicle is known to the at least one vehicle.

17. A downwardly compatible automated guided vehicle system according to claim 16 wherein the at least one automated guided vehicle further comprises means for calculating a path whereby the at least one vehicle is self-guided to reach a predetermined floor destination at a predetermined bearing.

18. A downwardly compatible automated guided vehicle system according to claim 1 wherein the at least one automated guided vehicle comprises at least one means for redundantly determining the bearing of the at least one automated guided vehicle relative to known guidepath sites and headings.

19. A downwardly compatible automated guided vehicle system according to claim 18 wherein the at least one redundant bearing determining means comprises an inertial platform means.

20. A downwardly compatible automated guided vehicle system according to claim 19 wherein the inertial platform means comprise tuning fork means.

21. A downwardly compatible automated guided vehicle system according to claim 20 wherein the tuning fork means comprise means for measuring angular rate of change of direction of the at least one automated guided vehicle and correcting for a drift rate which produces an error that if left uncorrected makes the tuning fork means unusable for determining the bearing of the at least one automated guided vehicle.

22. A downwardly compatible automated guided vehicle system according to claim 1 wherein the system further comprises at least one guidepath marked by localized passive guidewire means.

23. A downwardly compatible automated guided vehicle system according to claim 22 wherein the at least one guidepath marked by localized passive guidewire means comprises a temporary guidepath.

24. A downwardly compatible automated guided vehicle system according to claim 1 further comprising at least one automated guided vehicle which operates at different times over guidepaths marked by guidewires, update markers and passive guidewire means.

25. A downwardly compatible automated guided vehicle system according to claim 1 further comprising at least two incompatible automated guided vehicles which are operated at a common floor area and which each traverse only one type of guidepath.

26. A method by which automatic guided vehicles are controlled over a floor area in an automated guided vehicle system comprising the steps of:

providing an array of floor disposed marked paths comprising at least one path marked only by a guidewire and at least one path marked only by widely dispersed coordinate markers and at least two automatic guided vehicles;

selectively issuing communication signals from a control center, said signals comprising at least guidewire signals comprising vehicle motion commands and wireless signals comprising vehicle motion commands;

receiving said guidewire signals including the vehicle motion commands at a first automatic guided vehicle which is controlled by data transmitted through a guidewire;

receiving said wireless signals including the vehicle motion commands at a second automatic guided vehicle which is controlled by data transmitted by wireless transmitting means.

27. A method according to claim 26 further comprising the further steps of issuing communicating wireless signals from at least one automatic guided vehicle to the control center.

28. A method according to claim 26 further comprising the further steps of prioritizing and delaying receipt of some signals in favor of other signals.

29. A method according to claim 26 wherein steps of issuing wireless signals and guidewire signals comprise issuing the signals at substantially the same digital data rate.

30. A method according to claim 29 further comprising a precisely positioning step which comprises using vehicle power as an energy source for activating localized passive guidewire signals.

31. A method according to claim 26 comprising the following additional steps:

adding at least one update marker guidepath to the system;

providing at least one automatic guided vehicle which operates at one time along the guidewire guidepath and at another time along the update marker guidepath whereby the method of controlling automatic guided vehicles over a floor area is downwardly compatibly expanded to comprise inclusion of at least one guidepath marked exclusively by update markers.

32. A method according to claim 26 wherein the selectively issuing step comprises sending the same message over guidewire and wireless communications means.

33. A method according to claim 26 wherein the selectively issuing step comprises sending from the control center to said vehicle a 9600 baud data rate, transmission and reception of said baud rate being accomplished by radio transmitting and receiving means having a bandpass frequency of 3000 Hertz.

34. A method for communicating between automated guided vehicles and an automated guided vehicle control system, comprising the steps of:

selectively issuing communication signals from a control center, said signals comprising at least guidewire signals and wireless signals;

receiving the guidewire signals at at least a first automatic guided vehicle, said guidewire signals comprise a digital data string which restricts travel of the at least first vehicle to traversing guidewire guidepaths;

receiving the wireless signals at at least a second automatic guided vehicle, said wireless signals comprise the same content and format of said digital data string, which causes the at least second vehicle to travel to a predetermined destination.

35. A method according to claim 34 further comprising the step of communicating a guidewire signal from the at least first vehicle to the control center.

36. A method according to claim 34 further comprising the step of communicating wireless signals from the at least second vehicle to the control center.

37. A method according to claim 34 comprising the further step of:

communicating substantially the same form of digital data strings bidirectionally between each vehicle and the control center.