Detection of nuclear spills using swarm optimization algorithms

• US 8,838,271 B2
• Filed: 11/29/2010
• Issued: 09/16/2014
• Est. Priority Date: 10/14/2010
• Status: Active Grant

• Current Assignee: Indian Institute of Science
• Original Assignee: Indian Institute of Science
• Inventors: Ghose, Debasish, Krishnanand, Kaipa N., Thomas, Joseph
• Primary Examiner(s): Jen, Ian
• Application Number:
  US13/390,662
• Publication Number:
  US 20120232695A1
• Time in Patent Office: 1,387 Days
• Field of Search: 700/248, 700/258
• US Class Current: 700/248
• CPC Class Codes: G01T 7/00 Details of radiation-measuring instruments

Abstract

Systems and methods are provided for localizing a radiation or chemical source utilizing a swarm of robotic devices. According to one example, a robotic device will attempt to localize a source by measuring the concentration of source particles in air, and operating in a Chemotactic state, an Anemotactic state, or a Spiraling state.

Claims

1. At a robotic device, a method for searching for a radiation source, the method comprising:

measuring a concentration of radioactive particles;

determining a luciferin value based at least in part on the measured concentration of radioactive particles;

determining a number of other robotic devices that comprise a neighbor set of robotic devices; and

based on the determined luciferin value and the determined number of other robotic devices that comprise the neighbor set, operating in a Chemotactic state, an Anemotactic state, or a Spiraling state,

wherein operating in the Chemotactic state comprises the robotic device (a) assigning a probability value to each given robotic device in the neighbor set of robotic devices, each assigned probability value being based on the difference between a luciferin value broadcast by the given robotic device and the determined luciferin value, (b) the robotic device selecting, based on the assigned probability values, a given robotic device from among the neighbor set of robotic devices, and (c) the robotic device taking a step toward a location of the selected robotic device,

wherein operating in the Anemotactic state comprises the robotic device making a determination that a current wind has a speed greater than a threshold wind speed and responsively taking a step in the opposite direction of the wind, and

wherein operating in the Spiraling state comprises the robotic device taking a step along a substantially spiraled path.

2. The method of claim 1, wherein the concentration of radioactive particles comprises (i) a frequency of radioactive particles incident upon a detector, or (ii) a ratio of a number of detected radioactive particles to a number of detected non-radioactive particles.

3. The method of claim 1, further comprising periodically measuring a concentration of radioactive particles, wherein the luciferin value is the maximum of a threshold number of periodically measured concentration values.

4. The method of claim 1, wherein determining the number of other robotic devices that comprise a neighbor set of robotic devices comprises determining the number of other robotic devices that are both (i) located within a circular area defined by a decision radius parameter, and (ii) broadcasting a luciferin value greater than the determined luciferin value.

5. The method of claim 1, wherein the robotic device operates in the Chemotactic state when the determined number of robotic devices that comprise a neighbor set of robotic devices is greater than zero.

6. The method of claim 1, wherein the robotic device operates in the Anemotactic state when both (i) the determined number of other robotic devices that comprise a neighbor set of robotic devices is zero, and (ii) the determined luciferin value is non-zero.

7. The method of claim 1, wherein the robotic device operates in the Spiraling state when both (i) the determined number of other robotic devices that comprise a neighbor set of robotic devices is zero, and (ii) the determined luciferin value is zero.

8. A computer readable storage medium (CRM) having instructions stored thereon, which when executed by a computing device, causes the computing device to perform functions, the functions comprising:

determining a luciferin value based on a measured concentration of radioactive particles;

determining a number of robotic devices that comprise a neighbor set of robotic devices;

based on the determined luciferin value and the determined number of robotic devices that comprise a neighbor set of robotic devices, determining to operate in one of;

(i) a Chemotactic state in which the computing device at least causes a specific robotic device to;

assign a probability value to each given robotic device in the neighbor set of robotic devices, each assigned probability value being based on the difference between a luciferin value broadcast by the given robotic device and the determined luciferin value,

select, based on the assigned probability values, a given robotic device from among the neighbor set of robotic devices, and

take a step toward a location of the selected robotic device,

(ii) an Anemotactic state in which the computing device at least causes the specific robotic device to make a determination that a current wind has a speed greater than a threshold wind speed and responsively taking a step in the opposite direction of the wind,

and (iii) a Spiraling state in which the computing device at least causes the robotic device to move in a direction along a substantially spiraled path;

operating in the Chemotactic state;

operating in the Anemotactic state; and

operating in the Spiraling state.

9. The CRM of claim 8, wherein determining the number of robotic devices that comprise a neighbor set of robotic devices comprises determining the number of robotic devices that are both (i) located within a circular area defined by a decision radius parameter, and (ii) broadcasting a luciferin value greater than the determined luciferin value.

10. The CRM of claim 8, wherein the functions further comprise determining to operate in the Chemotactic state when the determined number of robotic devices that comprise a neighbor set of robotic devices is greater than zero.

11. The CRM of claim 8, wherein the functions further comprise determining to operate in the Anemotactic state when both (i) the determined number of robotic devices that comprise a neighbor set of robotic devices is zero, and (ii) the determined luciferin value is non-zero.

12. The CRM of claim 8, wherein the functions further comprise determining to operate in the Spiraling state when both (i) the determined number of robotic devices that comprise a neighbor set of robotic devices is zero, and (ii) the determined luciferin value is zero.

13. A robotic device comprising:

a computing device;

memory storage coupled to the computing device; and

instructions stored in the memory storage, which when executed by the computing device, cause the robotic device to carry out functions, the functions comprising;

measuring a concentration of radioactive particles;

determining a luciferin value based at least in part on the measured concentration of radioactive particles;

determining a number of other robotic devices that comprise a neighbor set of robotic devices;

based on the determined luciferin value and the determined number of robotic devices that comprise a neighbor set of robotic devices, operating in a Chemotactic state;

based on the determined luciferin value and the determined number of robotic devices that comprise a neighbor set of robotic devices, operating in an Anemotactic state; and

based on the determined luciferin value and the determined number of robotic devices that comprise a neighbor set of robotic devices, operating in a Spiraling state,

wherein operating in the Chemotactic state comprises the robotic device;

assigning a probability value to each given robotic device in the neighbor set of robotic devices, each assigned probability value being based on the difference between a luciferin value broadcast by the given robotic device and the determined luciferin value, selecting, based on the assigned probability values, a given robotic device from among the neighbor set of robotic devices, and taking a step toward a location of the selected robotic device,

wherein operating in the Anemotactic state comprises the robotic device making a determination that a current wind has a speed greater than a threshold wind speed and responsively taking a step in the opposite direction of the wind, and

wherein operating in the Spiraling state comprises the robotic device moving in a direction along a substantially spiraled path.

14. The robotic device of claim 13, further comprising means for broadcasting the determined luciferin value to other robotic devices.

15. The robotic device of claim 13, wherein the functions further comprise:

operating in the Chemotactic state when the determined number of robotic devices that comprise a neighbor set of robotic devices is greater than zero;

operating in the Anemotactic state when both (i) the determined number of robotic devices that comprise a neighbor set of robotic devices is zero, and (ii) the determined luciferin value is non-zero; and

operating in the Spiraling state when both (i) the determined number of robotic devices that comprise a neighbor set of robotic devices is zero, and (ii) the determined luciferin value is zero.