Disperse, aggregate and disperse (DAD) control strategy for multiple autonomous systems to optimize random search

• US 7,363,124 B1
• Filed: 12/21/1998
• Issued: 04/22/2008
• Est. Priority Date: 12/21/1998
• Status: Expired due to Fees

• Current Assignee: The United States of America As Represented By The Secretary of Agriculture
• Original Assignee: the united states of america as represented by the secretary of the navy
• Inventors: Duarte, Christiane N.
• Primary Examiner(s): Issing; Gregory C
• Application Number:
  US09/226,623
• Time in Patent Office: 3,410 Days
• Field of Search: 701/23, 701/200, 701/210, 701/214, 701/26, 701/25, 89/11.3
• US Class Current: 701/23
• CPC Class Codes: F41H 11/32 Decoy or sacrificial vehicles; Decoy or sacrificial devices attachable to vehicles
• CPC Class Codes: F41H 7/005 Unmanned ground vehicles, i.e. robotic, remote controlled or autonomous, mobile platforms carrying equipment for performing a military or police role, e.g. weapon systems or reconnaissance sensors F41H11/16 takes precedence

Abstract

A method for conducting a search of an area for targets by a number of vehicles. First each of the vehicles randomly disperses from the other vehicles. Then during an aggregate phase, each vehicle responds in a predesignated way to an encounter with one of the other vehicles. A number of specific search strategies may be followed which tend to direct the search in a particular designated direction or allow a successful searching vehicle to set the direction of the search. This method results in improved performance in conducting searches by robots or other vehicles.

Claims

1. A method for searching an area for targets by a vehicle in conjunction with a plurality of other vehicles comprising the steps of:

dispersing by turning said vehicle in a random direction to establish a current heading and moving said vehicle at a current speed for a random distance;

detecting targets using sensors on said vehicle during said vehicle dispersing step to establish a number of detected targets;

aggregating by turning said vehicle in another random direction to establish another heading and moving said vehicle a random distance at a current speed;

detecting targets using sensors on said vehicle during said aggregating step;

detecting other vehicles using sensors on said vehicle during said aggregating step;

responding in a predesignated way to the detection of said other vehicle and continuing said movement during said aggregating step if one of said plurality of other vehicles is not detected; and

repeating said dispersing and aggregating steps.

2. The method of claim 1 wherein said step of dispersing further comprises:

measuring an elapsed time; and

calculating a new velocity from said current velocity, said number of detected targets and said elapsed time.

3. The method of claim 2 further comprising the steps of:

providing said vehicle and said plurality of vehicles with an estimate of the target density in the search area, an estimate weight and an experience weight;

said step of calculating a new velocity comprising;

calculating a value for experience based on the experience weight and the elapsed time; and

calculating a new velocity from said experience value, the target density estimate and the estimate weight.

4. The method of claim 1 wherein the step of responding comprises:

transmitting said current heading to said detected other vehicle; and

receiving an other vehicle current heading from said detected other vehicle.

5. The method of claim 4 further comprising the step of:

providing said vehicle and said plurality of vehicles with preprogrammed conditions prior to initial dispersing, said preferred direction being multiple preferred directions; and

associating each said condition with one said preferred direction;

said step of responding further comprising;

establishing a current condition from said preprogrammed conditions;

comparing said current heading with said preferred direction associated with said current condition; and

comparing said received other vehicle current heading with said preferred direction associated with said current condition; and

altering said current heading to match said received other vehicle current heading if said received other vehicle current heading is closer to said preferred direction associated with said current condition.

6. The method of claim 5 wherein said steps of dispersing and aggregating further comprise:

measuring an elapsed time; and

calculating a new velocity from said current velocity, said number of detected targets and said elapsed time.

7. The method of claim 6 further comprising the steps of:

providing said vehicle and said plurality of vehicles with an estimate of the target density in the search area, an estimate weight and an experience weight;

said step of calculating a new velocity comprising;

calculating a value for experience based on the experience weight and the elapsed time; and

calculating a new velocity from said experience value, the target density estimate and the estimate weight.

8. The method of claim 4 further comprising the steps of:

transmitting said current number of detected targets to said detected other vehicle;

receiving an other vehicle number of detected targets form said detected other vehicle;

said step of responding further comprising;

comparing said current number of detected targets to said received other vehicle number of detected targets; and

altering said current heading to match said received other vehicle current heading if said received other vehicle number of detected targets is greater than said current number of detected targets.

9. The method of claim 8 wherein said step of dispersing further comprises:

measuring an elapsed time; and

calculating a new velocity from said current velocity, said number of detected targets and said elapsed time.

10. The method of claim 9 further comprising the steps of:

providing said vehicle and said plurality of vehicles with an estimate of the target density in the search area, an estimate weight and an experience weight;

said step of calculating a new velocity comprising;

calculating a value for experience based on the experience weight and the elapsed time; and

calculating a new velocity from said experience value, the target density estimate and the estimate weight.

11. The method of claim 4 further comprising the step of:

providing said vehicle and said plurality of vehicles with a preferred direction prior to initial dispersal;

said step of responding further comprising;

comparing said current heading with said preferred direction; and

altering said current heading to match said received other vehicle current heading if said received other vehicle current heading is closer to said preferred direction.

12. The method of claim 11 wherein said steps of dispersing and aggregating further comprise:

measuring an elapsed time; and

calculating a new velocity from said current velocity, said number of detected targets and said elapsed time.

13. The method of claim 12 further comprising the steps of:

providing said vehicle and said plurality of vehicles with an estimate of the target density in the search area, an estimate weight and an experience weight;

said step of calculating a new velocity comprising;

calculating a value for experience based on the experience weight and the elapsed time; and

calculating a new velocity form said experience value, the target density estimate and the estimate weight.

14. The method of claim 4 further comprising the steps of:

providing said vehicle and said plurality of vehicles with a preferred direction prior to initial dispersal;

transmitting said current number of detected targets to said detected other vehicle;

receiving an other vehicle number of detected targets from said detected other vehicle;

said step of responding further comprising;

comparing said current number of detected targets to said received other vehicle number of detected targets;

altering said current heading to match said received other vehicle current heading if said received other vehicle number of detected targets is greater than said current number of detected targets; and

altering said current heading to match said received other vehicle current heading if said received other vehicle current heading is closer to said preferred direction and if said received other vehicle number of detected targets is the same as said current number of detected targets.

15. The method of claim 14 wherein said step of dispersing further comprises:

measuring an elapsed time; and

calculating a new velocity from said current velocity, said number of detected targets and said elapsed time.

16. The method of claim 15 further comprising the steps of:

providing said vehicle and said plurality of vehicles with an estimate of the target density in the search area, an estimate weight and an experience weight;

said step of calculating a new velocity comprising;

calculating a value for experience based on the experience weight and the elapsed time; and

calculating a new velocity from said experience value, the target density estimate and the estimate weight.

17. The method of claim 4 further comprising the steps of:

providing said vehicle and said plurality of vehicles with a preferred direction prior to initial dispersal;

transmitting said current number of detected targets to said detected other vehicle;

receiving an other vehicle number of detected targets from said detected other vehicle;

said step of responding further comprising;

comparing said current number of detected targets to said received other vehicle number of detected targets;

altering said current heading to match said received other vehicle current heading if said received other vehicle number of detected targets is greater than said current number of detected targets; and

altering said current heading to match the preferred direction if said received other vehicle number of detected targets is less than said current number of detected targets.

18. The method of claim 17 wherein said step of dispersing further comprises:

measuring an elapsed time; and

calculating a new velocity from said current velocity, said number of detected targets and said elapsed time.

19. The method of claim 18 further comprising the steps of:

providing said vehicle and said plurality of vehicles with an estimate of the target density in the search area, an estimate weight and an experience weight;

said step of calculating a new velocity comprising;

calculating a value for experience based on the experience weight and the elapsed time; and

calculating a new velocity from said experience value, the target density estimate and the estimate weight.