Vehicle collision avoidance system

• US 4,379,497 A
• Filed: 09/02/1980
• Issued: 04/12/1983
• Est. Priority Date: 09/02/1980
• Status: Expired due to Term

• Current Assignee: Saurer Automation Systems, Inc.
• Original Assignee: Bell & Howell LLC (Böwe Systec AG)
• Inventors: Houskamp, Robert W., Hainsworth, Thomas E.
• Primary Examiner(s): Mitchell, David M.
• Application Number:
  US06/183,241
• Time in Patent Office: 952 Days
• Field of Search: 180/168, 180/167, 180/169, 180/271, 340/33, 318/587, 246/30, 246/182 A, 246/182 R, 104/88, 104/299, 343/7 A, 364/436
• US Class Current: 180/168
• CPC Class Codes: B61L 23/00 Control, warning or like safety means along the route or between vehicles or trains
• CPC Class Codes: G05D 1/0244 using reflecting strips

Abstract

An automatically guided vehicle (110) is disclosed which follows guide lines positioned in a predetermined guide path (102) on the floor. The guide path (102) includes coded markings and the vehicle comprises sensing circuitry (210) capable of sensing the markings and generating proximity signals indicative thereof. The coded markings can indicate approach of the vehicle into a "congestion" zone wherein other vehicles similarly situated can cause hazardous conditions therein. Radio frequency (RF) transmission circuitry (240) on the approaching vehicle (110) is responsive to the congestion zone indication signals to transmit and receive RF signals to and from other vehicles on the guide path (102). The approaching vehicle (110) performs various collision avoidance operations as determined by the received RF signals.

Claims

1. In an automatic guidance system having first and second self-propelled vehicles adapted to follow a predetermined guidepath having an intersecting portion defining a potential congestion zone on a floor surface, each of said vehicles having energizing means for driving the vehicle along said guidepath, the improvement which comprises:

marker means on said floor surface a spaced distance from said intersecting portion of said guidepath for indicating the proximity of said intersecting portion on said guidepath;

first sensing means on said first vehicle to detect said marker means and for generating a first proximity signal responsive thereto;

first transmitter means on said first vehicle and connected to said first sensing means for transmitting a polling signal responsive to said first proximity signal;

first receiver means on said first vehicle for detecting spatial communication signals generated by said second vehicle;

second sensing means on said second vehicle for detecting said marker means and generating a second proximity signal responsive thereto;

second receiver means on said second vehicle for receiving said polling signal;

second transmitter means on said second vehicle for transmitting a blocking signal in response to said polling signal when said second vehicle is within said potential congestion zone;

said first receiver means on said first vehicle is responsive to said blocking signal for generating a stop signal corresponding thereto; and

first control means on said first vehicle coupled to said first receiver means for disabling said energizing means of said first vehicle in response to said stop signal generated by said first receiver means until such time as said blocking signal is no longer received by said first receiver means, whereby said first vehicle will automatically stop when approaching said potential congestion zone as long as said second vehicle is passing therethrough.

2. An automatic guidance system in accordance with claim 1 characterized in that said system further comprises means for detecting said second vehicle being clear of said congestion zone.

3. An automatic guidance system in accordance with claim 2 characterized in that said second transmitter means ceases transmission of said blocking signal in response to detection of said second vehicle being clear of said congestion zone.

4. An automatic guidance system in accordance with claim 2 characterized in that said control means enables said first vehicle energizing means in response to detection of said second vehicle being clear of said congestion zone.

5. An automatic guidance system in accordance with claim 1 characterized in that said second transmitter means is further responsive to said second proximity signal for transmitting a further polling signal indicative of said second vehicle approaching said congestion zone.

6. An automatic guidance system in accordance with claim 5 characterized in that said first receiver means is adapted to receive said further polling signal and to generate information signals corresponding thereto;

and

said first transmitter means on said first vehicle is responsive to generation of said information signals for transmitting a blocking signal when said first vehicle is passing through such congestion zone.

7. An automatic guidance system in accordance with claim 1 characterized in that said system further comprises:

second control means on said second vehicle connected to said second sensing means and responsive to said second proximity signal for applying to said second transmitter means an information signal indicative of said marker means being detected by said second sensing means; and

said second transmitter means on said second vehicle is connected to said second control means on said second vehicle and is responsive to said information signal to spatially transmit a further polling signal corresponding to said information signal.

8. An automatic guidance system in accordance with claim 7 characterized in that said first receiver means is adapted to receive said further polling signal and to apply to said first control means a further information signal corresponding to said further polling signal;

said first control means is responsive to said further information signal corresponding to said further polling signal and to signals indicative of the position of said first vehicle along said guidepath to apply a said further information signal to said first transmitter means when said first vehicle is within said congestion zone; and

said first transmitter means is connected to said first control means and is responsive to said further information signal to transmit a further blocking signal corresponding thereto.

9. An automatic guidance system in accordance with claim 8 characterized in that said second receiver means is adapted to receive said further blocking signal transmitted by said first transmitter means on said first vehicle and apply to said second control means an information signal corresponding thereto;

and

said second control means is responsive to said information signal applied by said second transmitter means to disable said second vehicle energizing means.

10. An automatic guidance system in accordance with claim 9 characterized in that said second transmitter means is adapted to repetitively transmit said second polling signal at predetermined intervals of time until such time that no blocking signals are received by said second receiver means.

11. An automatic guidance system in accordance with claim 10 characterized in that said first transmitter means transmits said further blocking signal in response to said repetitive second polling signal when said first vehicle is within said congestion zone.

12. An automatic guidance system in accordance with claim 11 characterized in that said predetermined intervals of time are a function of a unique identification of said second vehicle.

13. An automatic guidance system in accordance with claim 2 characterized in that said means for detecting said second vehicle being clear of such congestion zone comprises means for detecting the distance travelled by said second vehicle within said congestion zone.

14. In an automatic guidance system having first and second self-propelled vehicles adapted to follow a predetermined guidepath having an intersecting portion on the floor surface, each of said vehicles having energizing means for driving said vehicles along said guidepath, the improvement which comprises:

means for applying activating signals to said first vehicle energizing means when said first vehicle is stopped on said guidepath;

transmitter means on said first vehicle responsive to said activating signals for transmitting a polling signal;

receiver means on said second vehicle for detecting said polling signal;

transmitter means on said second vehicle for transmitting a blocking signal in response to said receiving means on said second vehicle receiving said polling signal when said second vehicle is within a predetermined area on said guidepath;

receiver means on said first vehicle for detecting said blocking signal and for generating a stop signal corresponding thereto; and

control means on said first vehicle coupled to said receiver means on said first vehicle and responsive to said stop signal for prohibiting application of said activating signals to said first vehicle energizing means until such time as said blocking signal is no longer received by said receiver means on said first vehicle, whereby said first vehicle will remain stopped on said guidepath as long as said second vehicle is passing through said predetermined area.

15. A method for prohibiting collisions between first and second vehicles adapted to follow a predetermined guidepath having an intersecting portion defining a potential congestion zone on a floor surface, said method comprising the steps of:

(a) sensing the approach of said first vehicle into said intersecting portion;

(b) transmitting from said first vehicle a polling signal in response to the sensed approach of said first vehicle into said intersecting portion;

(c) receiving said polling signal at said second vehicle and transmitting a blocking signal in response thereto only when said second vehicle is within said collision zone;

(d) receiving said blocking signal at said first vehicle; and

(e) stopping said first vehicle in response to said blocking signal and prohibiting said first vehicle from entering said intersecting portion until such time as said blocking signal is no longer received at said first vehicle.

16. A method for prohibiting collisions between first and second vehicles automatically guided along a guidepath having intersecting guide lines, said method comprising the steps of:

(a) sensing the approach of said first vehicle to a guidepath intersection and generating polling signals from said first vehicle indicative thereof;

(b) receiving said polling signals from said first vehicle at said second vehicle;

(c) transmitting blocking signals from said second vehicle in response to said polling signals only when said second vehicle is within a predetermined zone surrounding said guidepath intersection; and

(d) ceasing movement of said first vehicle in response to reception by said first vehicle of said transmitted blocking signals.

17. The method in accordance with claim 24 characterized in that said method further comprises:

(a) transmitting from said first vehicle additional polling signals at predetermined intervals of time;

(b) waiting a further predetermined interval of time after transmitting said additional polling signals and generating energizing signals to establish movement of said first vehicle through said guidepath intersection in the absence of blocking signals received by said first vehicle during said further predetermined interval of time.