Self-Contained Holonomic Tracking Method and Apparatus for Non-Destructive Inspection

• US 20140278221A1
• Filed: 03/12/2013
• Published: 09/18/2014
• Est. Priority Date: 03/12/2013
• Status: Active Grant

• Current Assignee: The Boeing Co.
• Original Assignee: The Boeing Co.
• Inventors: Troy, James J., Lea, Scott W., Georgeson, Gary E., Nelson, Karl E., Wright, Daniel James
• Granted Patent: US 9,470,658 B2
• Time in Patent Office: Days
• US Class Current: 702/151
• CPC Class Codes: G01C 22/02 by conversion into electric waveforms and subsequent integration, e.g. using tachometer generator G01C22/002, G01C22/004, G01C22/006 take precedence
• CPC Class Codes: G01N 2291/106 one or more transducer arrays
• CPC Class Codes: G01N 27/9013 Arrangements for scanning
• CPC Class Codes: G01N 29/04 Analysing solids using acoustic emission techniques G01N29/14
• CPC Class Codes: G01N 29/225 Supports, positioning or alignment in moving situation
• CPC Class Codes: G01N 29/265 by moving the sensor relative to a stationary material
• CPC Class Codes: G05D 1/0272 comprising means for registering the travel distance, e.g. revolutions of wheels measuring distance traversed on the ground by vehicles, e.g. using odometers G01C22/00

Abstract

A self-contained, holonomic motion tracking solution for supplementing the acquisition of inspection information on the surface of a structure, thereby enabling the real-time production of two-dimensional images from hand-held and automated scanning by holonomic-motion of non-destructive inspection (NDI) sensor units (e.g., NDI probes). The systems and methods disclosed enable precise tracking of the position and orientation of a holonomic-motion NDI sensor unit (hand-held or automated) and conversion of the acquired tracking data into encoder pulse signals for processing by a NDI scanning system.

Claims

1. A method for tracking a device that is coupled to a plurality of omni wheels, comprising:

(a) converting rotation of each omni wheel into respective encoder data;

(b) computing an absolute angle representing an orientation of the device relative to a coordinate system of the surface based in part on said encoder data;

(c) computing relative changes in X and Y positions of the device relative to said coordinate system of the surface based in part on said encoder data; and

(d) computing an absolute position of the device relative to said coordinate system of the surface based in part on said computed absolute angle and said computed changes in X and Y positions.

2. The method as recited in claim 1, wherein steps (b) through (d) are repeated at regular intervals of time to provide absolute angles and absolute positions of the device over a period of time.

3. The method as recited in claim 1, further comprising using said computed absolute angle and absolute position to position and orient a three-dimensional model of the device in a virtual environment.

4. The method as recited in claim 1, wherein the computations of steps (b) through (d) take into account that the device has a four-omni wheel, perpendicular, double-differential configuration.

5. The method as recited in claim 1, wherein the computations of steps (b) through (d) take into account that the device has three omni wheels equidistant from a common center point with axes of rotations at 120 degree angles with respect to each other.

6. The method as recited in claim 1, wherein the computations of steps (b) through (d) take into account that the device has a four-omni wheel, bogie configuration.

7. The method as recited in claim 1, wherein the device is an inspection unit, the method further comprising:

acquiring inspection data; and

displaying an image in which the inspection data is arranged based on the respective absolute angle and absolute position of the device when each inspection datum was acquired.

8. The method as recited in claim 7, further comprising:

converting the computed absolute angles and absolute positions into simulated encoder pulses; and

correlating the inspection data with the simulated encoder pulses,

wherein said displaying step arranges the inspection data in accordance with the results of said correlating step.

9. A device comprising:

a frame;

a plurality of omni wheels rotatably coupled to said frame;

a plurality of rotational encoders respectively coupled to said plurality of omni wheels; and

an inspection unit connected to said frame.

10. The device as recited in claim 9, wherein said plurality of omni wheels are arranged in a four-omni wheel, perpendicular, double-differential configuration.

11. The device as recited in claim 9, wherein said plurality of omni wheels comprises three omni wheels equidistant from a common center point with axes of rotations at 120 degree angles with respect to each other.

12. The device as recited in claim 9, wherein said plurality of omni wheels are arranged in a four-omni wheel, bogie configuration.

13. The device as recited in claim 9, wherein said inspection unit comprises a sensor array.

14. The device as recited in claim 13, wherein said sensor array comprising a multiplicity of ultrasonic transducers.

15. An inspection system comprising a scanning device, a display device and a computer system, said scanning device and said display device being coupled to communicate with said computer system,

wherein said scanning device comprises:

a frame;

a plurality of omni wheels rotatably coupled to said frame;

a plurality of rotational encoders respectively coupled to said plurality of omni wheels for converting rotation of each omni wheel into respective encoder data; and

an inspection unit connected to said frame, and

wherein said computer system is programmed to execute the following operations;

(a) computing an absolute angle representing an orientation of the device relative to a coordinate system of the surface based in part on said encoder data;

(b) computing relative changes in X and Y positions of the device relative to said coordinate system of the surface based in part on said encoder data;

(c) computing an absolute position of the device relative to said coordinate system of the surface based in part on said computed absolute angle and said computed changes in X and Y positions;

(d) controlling said inspection unit to acquire inspection data;

(e) controlling said display device to display an image in which the inspection data is arranged based on the respective absolute angle and absolute position of the device when each inspection datum was acquired.

16. The inspection system as recited in claim 15, wherein said computer system is further programmed to execute the following operations:

converting the computed absolute angles and absolute positions into simulated encoder pulses; and

correlating the inspection data with the simulated encoder pulses,

wherein said displaying operation arranges the inspection data in accordance with the results of said correlating operation.

17. The inspection system as recited in claim 15, wherein said computer system is programmed to repeat operations (a) through (c) at regular intervals of time to provide absolute angles and absolute positions of the device over a period of time.

18. The inspection system as recited in claim 15, wherein said inspection unit comprises a sensor array.

19. The inspection system as recited in claim 18, wherein said sensor array comprising a multiplicity of ultrasonic transducers.

20. A tracking system comprising a movable device and a computer system, said movable device being coupled to communicate with said computer system,

wherein said movable device comprises:

a frame;

a plurality of omni wheels rotatably coupled to said frame; and

a plurality of rotational encoders respectively coupled to said plurality of omni wheels for converting rotation of each omni wheel into respective encoder data, and

wherein said computer system is programmed to execute the following operations;

(a) computing an absolute angle representing an orientation of the device relative to a coordinate system of the surface based in part on said encoder data;

(b) computing relative changes in X and Y positions of the device relative to said coordinate system of the surface based in part on said encoder data; and

(c) computing an absolute position of the device relative to said coordinate system of the surface based in part on said computed absolute angle and said computed changes in X and Y positions.

21. The tracking system as recited in claim 20, wherein said plurality of omni wheels are arranged in a four-omni wheel, perpendicular, double-differential configuration.

22. The tracking system as recited in claim 20, wherein said plurality of omni wheels comprises three omni wheels equidistant from a common center point with axes of rotations at 120 degree angles with respect to each other.

23. The tracking system as recited in claim 20, wherein said plurality of omni wheels are arranged in a four-omni wheel, bogie configuration.