System for controlling unmanned vehicles at intersections

• US 5,845,725 A
• Filed: 12/20/1995
• Issued: 12/08/1998
• Est. Priority Date: 01/09/1995
• Status: Expired due to Fees

• Current Assignee: Bishamon Industries Corporation
• Original Assignee: Bishamon Industries Corporation
• Inventors: Kawada, Hiroyuki
• Primary Examiner(s): Johnson, Brian L.
• Assistant Examiner(s): YU, MIN SON
• Application Number:
  US08/575,859
• Time in Patent Office: 1,084 Days
• Field of Search: 180/167, 180/168, 180/169, 340/901, 340/902, 340/903, 340/905, 340/917, 340/933, 364/460, 364/461, 318/587
• US Class Current: 180/167
• CPC Class Codes: G05D 1/0265 using buried wires
• CPC Class Codes: G05D 1/0289 with means for avoiding collisions between vehicles vehicle fittings for automatically controlling speed including means for detecting potential obstacles B60K31/0008; avoiding obstacles by action on the steering system B62D; radar, sonar, lidar systems designed for anti-collision purposes G01S13/93, G01S15/93, G01S17/93
• CPC Class Codes: G08G 1/0965 responding to signals from another vehicle, e.g. emergency vehicle

Abstract

A transportation system has several guide strips for unmanned vehicles. The guide strips define an intersection, and a mark warning of the intersection is disposed adjacent each guide strip before the intersection. Each of the vehicles has a detector for the respective mark, a signal transmitter, a receiver for signals coming from the other vehicles, and a timer for measuring a timed interval shorter than the time required to travel from the respective mark to the intersection. The transmitters and timers begin to operate in response to detection of the respective marks. After a selected vehicle passes the respective mark, its receiver attempts to pick up signals from the other vehicles. If no other vehicles are detected before the selected vehicle reaches the intersection, the selected vehicle passes through the intersection without stopping. On the other hand, should the selected vehicle detect another vehicle before the respective timed interval ends, the selected vehicle comes to a halt upstream of the intersection, and stops transmitting, when the timed interval is up. The selected vehicle remains stationary for a predetermined stopping interval following which it begins to move and transmit again if it no longer detects another vehicle. To prevent collisions at the intersection, the timed intervals and stopping intervals differ from vehicle to vehicle.

Claims

1. A method of operating unmanned vehicles comprising the steps of:

conveying said vehicles along respective paths towards an intersection constituting part of a predetermined area;

warning said vehicles of said intersection at respective locations upstream of said area;

sensing by each of said vehicles, during at least one timed interval following arrival at the respective location, for another of said vehicles, said timed intervals differing from vehicle to vehicle;

passing through said intersection any of said vehicles which, while upstream of said area, fails to detect another of said vehicles; and

stopping a first one of said vehicles upstream of said area when the respective timed interval ends while said first vehicle is upstream of said area and detects a second one of said vehicles.

2. The method of claim 1, wherein the warning steps comprise detecting the respective locations.

3. The method of claim 1, further comprising stopping a third one of said vehicles upstream of said area, the stopping step for each of said first and third vehicles being performed for a predetermined interval, and said predetermined intervals differing.

4. The method of claim 1, further comprising transmitting a signal from each of said vehicles during the respective timed interval, the sensing step for each of said vehicles including sensing for the signals transmitted by another of said vehicles.

5. The method of claim 4, wherein the warning steps comprise detecting, and the transmitting steps are performed in response to detection of, the respective locations.

6. The method of claim 4, wherein the transmitting step for said first vehicle is interrupted in response to the stopping step.

7. The method of claim 4, wherein said signals are electrical.

8. A transportation system comprising:

a plurality of guides defining respective paths, said paths defining an intersection which constitutes part of a predetermined area;

a plurality of unmanned vehicles movable along respective ones of said guides; and

warning means for warning said vehicles of said intersection when said vehicles are at respective locations spaced from said area, each of said vehicles including a sensor for said warning means, a signal transmitter, a receiver for signals coming from another of said vehicles, and a timer for measuring at least one timed interval following arrival at the respective location, said timed intervals differing from vehicle to vehicle, and said receivers being operative during the respective timed intervals, each of said vehicles being programmed to stop for a predetermined interval when the respective timed interval ends while the vehicle is upstream of said area and detects another of said vehicles.

9. The system of claim 8, wherein said warning means comprises a warning element along each of said guides at the respective location.

10. The system of claim 8, wherein said timers are activated in response to detection of said warning means.

11. The system of claim 8, wherein said predetermined intervals differ.

12. The system of claim 8, wherein said transmitters are operative during the respective timed intervals.

13. The system of claim 12, wherein said transmitters are activated in response to detection of said warning means.

14. The system of claim 12, wherein said transmitters are deactivated in response to stopping of the respective vehicles.

15. The system of claim 8, wherein said transmitters are designed to transmit electrical signals.