Mobile autonomous robotic apparatus for radiologic characterization

• US 5,936,240 A
• Filed: 01/29/1997
• Issued: 08/10/1999
• Est. Priority Date: 01/30/1996
• Status: Expired due to Fees

• Current Assignee: United States Department of Energy (Government of the United States of America)
• Original Assignee: United States Department of Energy (Government of the United States of America)
• Inventors: Harpring, Larry J., Jones, Joel D., Dudar, Aed M., Ward, Clyde R., Collins, Montenius X., Mallet, William R., Anderson, Erin K.
• Primary Examiner(s): Hannaher, Constantine
• Application Number:
  US08/790,923
• Time in Patent Office: 923 Days
• Field of Search: 250/336.1, 250/361 R, 250/367, 250/369, 250/253
• US Class Current: 250/253
• CPC Class Codes: G01T 7/00 Details of radiation-measuring instruments
• CPC Class Codes: G01V 5/02 specially adapted for surface logging, e.g. from aircraft

Abstract

A mobile robotic system that conducts radiological surveys to map alpha, beta, and gamma radiation on surfaces in relatively level open areas or areas containing obstacles such as stored containers or hallways, equipment, walls and support columns. The invention incorporates improved radiation monitoring methods using multiple scintillation detectors, the use of laser scanners for maneuvering in open areas, ultrasound pulse generators and receptors for collision avoidance in limited space areas or hallways, methods to trigger visible alarms when radiation is detected, and methods to transmit location data for real-time reporting and mapping of radiation locations on computer monitors at a host station. A multitude of high performance scintillation detectors detect radiation while the on-board system controls the direction and speed of the robot due to pre-programmed paths. The operators may revise the preselected movements of the robotic system by ethernet communications to remonitor areas of radiation or to avoid walls, columns, equipment, or containers. The robotic system is capable of floor survey speeds of from 1/2-inch per second up to about 30 inches per second, while the on-board processor collects, stores, and transmits information for real-time mapping of radiation intensity and the locations of the radiation for real-time display on computer monitors at a central command console.

Claims

1. An apparatus for performing characterization of radioactive contamination on surfaces at a location within an area, said apparatus measuring the intensity of surface radiation and the location of said surface radiation, said apparatus comprising:

a platform;

a drive unit providing locomotion of said platform;

a first detection unit carried by said platform for locating obstacles in a path of said platform;

a second detection unit carried by said platform for navigating said platform in a preselected path over a surface;

a plurality of radiation detectors carried by said platform;

a processor controlling movement of said platform carried by said platform; and

a communications device carried by said platform for remotely communicating the intensity of surface radiation and the location of surface radiation at each time of detection by the plurality of radiation detectors.

2. The platform as recited in claim 1 wherein said drive unit providing locomotion comprises:

a motor;

a battery power source for the motor;

a means for transferring motion from said motor, said means controlled by said processor;

at least two wheels connected to the means for transferring motion for movement of said platform over areas of approximately level surfaces;

a third wheel providing stability for said platform; and

said third wheel providing maneuverability over said areas for said platform.

3. The platform as recited in claim 1 wherein said first detection unit for locating obstacles in the path of said platform further comprises:

a plurality of ultrasound pulse emitters located on the front, side, and rear of said platform;

a plurality of ultrasound pulse receivers located on the front, side, and rear of said platform;

said processor directing said emitters to generate ultrasound pulses from said emitters; and

said processor receiving ultrasound pulse detection signals indicative of obstacles from said receivers.

4. The first detection unit for locating obstacles as recited in claim 3 wherein said processor further performs the steps of:

interpreting said ultrasound pulse detection signals;

controlling the movement of said platform to avoid said obstacles; and

directing the movement of said platform to a pre-selected path over the area to be mapped for radiation.

5. The platform as recited in claim 1 wherein said second detection unit for navigating said platform further comprises:

a light unit producing laser light pulses;

a light unit receiving laser light pulses reflected off of obstacles;

said processor interpreting the reflected light data from obstacles in the path of the platform;

said processor directing the movement of the platform to avoid said obstacles; and

said processor directing the return of said platform to said preselected path.

6. The platform as in claim 1, wherein said plurality of radiation detectors carried by said platform further comprises:

said detectors comprising scintillation detectors;

a detection face located on each of said scintillation detectors, said detection face pointing downward;

said plurality of detectors located in front of the platform close to the surface, said plurality of detectors assembled side by side in the shape of a chevron, a point of said chevron leading the platform;

said plurality of detectors attached underneath a single frame assembly in front of the platform; and

said single frame assembly attached to an adjusting mechanism to lower or raise the single frame assembly.

7. The plurality of radiation detectors as recited in claim 6, wherein each detector further comprises:

a component of plastic separately enclosing each scintillation detector with a window oriented down toward said surface, with the window transparent to radiation;

said scintillation detector containing a radiation detector constructed of zinc sulfide, said zinc sulfide detector being bonded to said detection face, said detection face being located in front of said platform close to said surface to point down toward said surface;

a light-tight cover covering said scintillation detector; and

an independent microcomputer processor communicating information from said scintillation detector to the on-board processor.

8. The plurality of radiation detectors as recited in claim 7, wherein each detector is assembled side by side in the single frame assembly, further comprising a removable protective screen for the downward pointing faces of the detectors.

9. The platform as cited in claim 1, wherein said communications device carried by said platform for remotely communicating the location of radiation detected further performs the steps of:

communicating by radio transmissions with a central data collection station;

communicating by radio transmission the type of radiation detected as the radiation is detected;

communicating by radio transmission the location of the radiation detected as the location is detected;

communicating by radio transmission the intensity of radiation detected over a preselected level of radiation as the intensity is detected; and

communicating by radio transmission a format for mapping of said location of all radiation detected.

10. The communications device as recited in claim 9 for communicating the location of radiation detected further performing the step of communicating by ethernet frequency to and from the central data collection station, at each time of detection of the radiation.

11. The platform as recited in claim 1, wherein said processor for controlling movement carried by said platform controls the repetitive monitoring for radiation and further comprises:

a first set of instructions for halting the forward progress of said platform when radiation is detected over a preselected limit at a location;

a second set of instructions for requiring the platform to back up to said location of detected radiation;

a third set of instructions for controlling the platform in a stationary mode over the location of detected radiation; and

a fourth set of instructions for resuming the platform locomotion to a preselected direction and speed over the surface.

12. The processor for controlling movement as recited in claim 11, wherein said processor further comprises a set of instructions for operation of the radiation detectors for repetitive radiation detection during the time that said platform is stationary.

13. The processor for controlling movement as recited in claim 11, wherein said processor further comprises a set of instructions for operation of a plurality of alarm lights during the detection of radiation by said detectors and while said platform is stationary.

14. The processor for controlling movement as recited in claim 11, wherein said locomotion over said preselected path is at variable speeds of from about one-half inch per second to about thirty inches per second.

15. An apparatus for performing characterization of radioactive contamination on surfaces within an area, said apparatus measuring the intensity of surface radiation and the location of said surface radiation, said apparatus comprising:

a platform;

a drive unit of said platform;

a plurality of scintillation detectors carried by said platform;

a plurality of alarms for alerts upon detection of surface radiation over a preselected limit;

a processor controlling said scintillation detectors and alarms; and

a communications device carried by said platform for remotely communicating the type of surface radiation, the intensity of surface radiation, and the location of surface radiation at each time of detection by the plurality of scintillation detectors.

16. The platform as recited in claim 15 wherein the plurality of scintillation detectors further comprises:

a frame assembly, said frame assembly enclosing said plurality of scintillation detectors;

said plurality of scintillation detectors located in front of the platform close to the surface and assembled side by side in the shape of a chevron with a point of said chevron leading the platform;

said plurality of scintillation detectors attaching to said frame assembly in front of the platform; and

an adjusting mechanism to lower or raise said frame assembly connected to the front of the platform.

17. The platform as recited in claim 15 wherein the plurality of alarms for alerts further comprises:

an alarm light located on top of the platform;

an alarm light located on top of said frame assembly;

said processor carried by the platform for generating an alarm signal to the alarm lights; and

said processor generating alarm signals to the alarm lights when said plurality of scintillation detectors detect radiation over a preselected limit.

18. The platform as recited in claim 17 wherein said processor generating said alarm signal further provides the continued generation of said alarm signal during the detection of radiation on said surface by said plurality of scintillation detectors.

19. The platform as recited in claim 17 wherein said processor generating said alarm signal further generates a signal to end said alarm signal when the platform resumes forward movement.

20. The platform as recited in claim 15, wherein said processor for controlling the detectors and alarms further comprises:

an on-board computer receiving electrical signals when said plurality of scintillation detectors detect a location of radiation on said surface of the area;

said on-board computer generating a set of instructions for controlling the platform movement to back-up to said location of radiation on said surface;

said on-board computer generating a second set of instructions for triggering an alarm light during monitoring by said plurality of scintillation detectors for a preselected period of time;

said on-board computer generating a third set of instructions for controlling the platform locomotion to return to a pre-selected path over said surface after said preselected period of time; and

said on-board computer generating a fourth set of instructions for controlling said plurality of scintillation detectors to resume detection during locomotion over said preselected path.