Position and orientation tracking system

• US 5,748,321 A
• Filed: 05/07/1996
• Issued: 05/05/1998
• Est. Priority Date: 05/07/1996
• Status: Expired due to Fees

• Current Assignee: United States Department of Energy (Government of the United States of America)
• Original Assignee: United States Of America As Represented By The Department Of Energy
• Inventors: Gee, Timothy F., Armstrong, Gary A., Burks, Barry L., DePiero, Fred W., Muller, Richard C., Jansen, John F.
• Primary Examiner(s): Font, Frank G.
• Assistant Examiner(s): Ratliff, Reginald A.
• Application Number:
  US08/646,187
• Time in Patent Office: 728 Days
• Field of Search: 356/386, 356/387, 356/376, 356/222, 356/226
• US Class Current: 356/635
• CPC Class Codes: G01S 1/7034 Mounting or deployment thereof
• CPC Class Codes: G01S 1/7038 Signal details
• CPC Class Codes: G01S 2201/01 adapted for specific applications or environments
• CPC Class Codes: G01S 5/16 using electromagnetic waves other than radio waves

Abstract

A position and orientation tracking system presents a laser scanning appaus having two measurement pods, a control station, and a detector array. The measurement pods can be mounted in the dome of a radioactive waste storage silo. Each measurement pod includes dual orthogonal laser scanner subsystems. The first laser scanner subsystem is oriented to emit a first line laser in the pan direction. The second laser scanner is oriented to emit a second line laser in the tilt direction. Both emitted line lasers scan planes across the radioactive waste surface to encounter the detector array mounted on a target robotic vehicle. The angles of incidence of the planes with the detector array are recorded by the control station. Combining measurements describing each of the four planes provides data for a closed form solution of the algebraic transform describing the position and orientation of the target robotic vehicle.

Claims

1. A system for tracking the position and orientation of a moving target object, comprising:

(A) laser scanning means for scanning the moving target object and generating direction information;

(B) detection means carried by the moving target object for detecting scanning of the moving target object by the laser scanning means and generating a detection signal; and

(C) control means for controlling the laser scanning means based on the direction information and the detection signal while the target object is moving.

2. A system according to claim 1, wherein:

the control means operate to record scanning of the moving target object by the laser scanning means.

3. A system according to claim 1, wherein:

the control means are communicatively coupled to the laser scanning means and to the detection means.

4. A system according to claim 1, wherein the control means comprise:

means for correlating the direction information generated by the laser scanning means and the detection signal generated by the detection means to determine the position and orientation of the moving target object while the target object is moving.

5. A system according to claim 1, wherein the laser scanning means comprise:

a first measurement pod;

a second measurement pod; and

the first measurement pod and the second measurement pod are each communicatively coupled to the control means.

6. A system according to claim 5, wherein the first measurement pod and the second measurement pod each comprise:

a first laser scanner subsystem for generating a first line laser; and

a second laser scanner subsystem for generating a second line laser which is directed orthogonally to the first line laser.

7. A system according to claim 5, wherein the first measurement pod and the second measurement pod each comprise:

a box which is capable of being articulated about two orthogonal axes.

8. A system according to claim 7, wherein the box comprises:

a first laser scanner subsystem, and

a second laser scanner subsystem.

9. A system according to claim 8, wherein the first laser scanner subsystem and the second laser scanner subsystem each comprise:

a laser source and a multi-faceted polygonal mirror for generating a line laser.

10. A system according to claim 9, wherein the first laser scanner subsystem and the second laser scanner subsystem each further comprise:

a laser driver coupled to the laser source.

11. A system according to claim 1, wherein the detection means comprise:

an array of detector modules.

12. A system according to claim 11, wherein each detector module comprises:

an infrared photodiode and an optical filter.

13. A system according to claim 1, wherein:

the control means are communicatively coupled to both the laser scanning means and the detection means, and include a VME-based control processor and a digital controller.

14. A system according to claim 11, wherein the detection means further comprise:

means for identifying one or more detector modules of the array of detector modules that sensed an impinging laser.

15. A system according to claim 14, wherein the detection means further comprise:

means for determining a frequency of the impinging laser.

16. A system according to claim 15, wherein:

the detection signal comprises data which represent the frequency of the impinging laser.

17. A system according to claim 1, wherein the detection means comprise:

an array of detector modules for detecting a scanning laser,

each detector module of the array of detector modules comprising an infrared photodiode and optical filter for generating a photodiode signal responsive to the scanning laser; and

a bank of bandpass filters coupled to each photodiode for filtering the photodiode signal,

the bank of bandpass filters is operative to generate a filter signal which identifies a frequency of the scanning laser.

18. A system according to claim 17, wherein the control means comprise:

a master oscillator which can be operated synchronously with the bank of bandpass filters for recording the time that the filter signal is generated.

19. A method for tracking the position and orientation of a moving target object, comprising the steps of:

(A) scanning the moving target object with three or more lasers;

(B) detecting scanning of the moving target object with the three or more lasers;

(C) determining the direction of each of the three or more lasers to the moving target object;

(D) determining the time that each of the three or more lasers scanned the moving target object;

(E) determining the position and orientation of the moving target object based on;

(i) the direction of each of the three or more lasers to the moving target object and

(ii) the time that each of the three or more lasers scanned the moving target object; and

(F) following the moving target object with the three or more lasers.

20. A method according to claim 19, wherein step (A) comprises the steps:

providing a first laser scanner subsystem and a second laser scanner subsystem;

radiating a first laser from the first laser scanner subsystem; and

radiating a second laser from the second laser scanner subsystem.

21. A method according to claim 20, wherein step (A) further comprises the steps:

providing a third laser scanner subsystem and a fourth laser scanner subsystem;

radiating a third laser from the third laser scanner subsystem; and

radiating a fourth laser from the fourth laser scanner subsystem.

22. A method according to claim 21, wherein step (D) comprises the steps:

determining three or more times responsive to each of the first laser, the second laser, the third laser, and the fourth laser scanning the moving target object; and

generating a time-stamp signal for each of the three or more times.

23. A method according to claim 22, wherein step (E) comprises the step:

measuring the position and orientation of the moving target object based on the three or more time-stamp signals.