Six degree-of-freedom laser tracker that cooperates with a remote projector to convey information

• US 8,848,203 B2
• Filed: 04/11/2012
• Issued: 09/30/2014
• Est. Priority Date: 04/15/2011
• Status: Active Grant

• Current Assignee: Faro Technologies Incorporated
• Original Assignee: Faro Technologies Incorporated
• Inventors: Bridges, Robert E., Parker, David H.
• Primary Examiner(s): Ton, Tri
• Assistant Examiner(s): MERRELL II, WILLIE C
• Application Number:
  US13/444,043
• Publication Number:
  US 20120262728A1
• Time in Patent Office: 902 Days
• Field of Search: 356/3, 356/601, 356614-624
• US Class Current: 356/614
• CPC Class Codes: G01B 11/03 by measuring coordinates of points
• CPC Class Codes: G01C 15/002 Active optical surveying means optical plumbing G01C15/105
• CPC Class Codes: G01C 3/08 Use of electric radiation detectors
• CPC Class Codes: G01S 17/42 Simultaneous measurement of distance and other co-ordinates indirect measurement G01S17/46
• CPC Class Codes: G01S 17/66 Tracking systems using electromagnetic waves other than radio waves
• CPC Class Codes: G01S 17/89 for mapping or imaging
• CPC Class Codes: G01S 7/4808 Evaluating distance, position or velocity data
• CPC Class Codes: G01S 7/4813 Housing arrangements
• CPC Class Codes: G01S 7/4818 using optical fibres
• CPC Class Codes: G01S 7/491 Details of non-pulse systems
• CPC Class Codes: G06F 17/40 Data acquisition and logging for input to computer G06F3/00
• CPC Class Codes: G16Z 99/00 Subject matter not provided for in other main groups of this subclass

Abstract

A method of conveying information to a user of a coordinate measurement device, includes providing a first target projector, sending a first light beam from the device to a retroreflector; receiving a second light beam from the retroreflector; measuring the orientational and translational sets, the translational set based on the second light beam; selecting first information to be conveyed from the group consisting of one or more positions on the object, a direction indicated by a moving pattern, a message that includes one or more symbols or alphanumeric characters, a hidden feature, a measured object characteristic, a modeled characteristic, a magnified representation of surface characteristics, a pattern having meaning according to a rule, and combinations thereof; determining a first light pattern corresponding to the information; storing the first light pattern; and projecting the first light pattern onto the object based on the translational and orientational sets.

Claims

1. A method of conveying first information to a user of a coordinate measurement device by projecting a first pattern with a first target projector, the method comprising steps of:

providing the first target projector having a target-projector frame of reference and including a body, a first retroreflector, and a projector, wherein the first retroreflector and projector are rigidly affixed to the body, the first target projector mechanically detached from the coordinate measurement device, the projector configured to project a pattern of light in two dimensions, the pattern of light forming a three-dimensional pattern of light when intercepted by a three-dimensional object;

providing the coordinate measurement device having a device frame of reference, the coordinate measurement device including a first motor, a second motor, a first angle measuring device, a second angle measuring device, a distance meter, a position detector, a control system, and a device processor, the coordinate measurement device configured to send a first beam of light to the first retroreflector and to receive a second beam of light from the first retroreflector, the second beam of light being a portion of the first beam of light, the first motor and the second motor together configured to direct the first beam of light to a first direction, the first direction determined by a first angle of rotation about a first axis and a second angle of rotation about a second axis, the first angle of rotation produced by the first motor and the second angle of rotation produced by the second motor, the first angle measuring device configured to measure the first angle of rotation and the second angle measuring device configured to measure the second angle of rotation, the distance meter configured to measure a first distance from the coordinate measurement device to the first retroreflector, the distance meter being selected from the group consisting of an interferometer and an absolute distance meter, the position detector configured to receive a second portion of the second beam of light and to send a first signal to the control system, the first signal produced in response to a position of the second portion on the position detector, the control system configured to send a second signal to the first motor, to send a third signal to the second motor, and to adjust the first direction of the first beam of light to the position in space of the first retroreflector, the second signal and the third signal based at least in part on the first signal, the device processor configured to determine a translational set and an orientational set, the translational set being values of three translational degrees of freedom of the first target projector in the device frame of reference and the orientational set being values of three orientational degrees of freedom of the first target projector in the device frame of reference, the translational set and the orientational set substantially defining a position and orientation of the first target projector in space, the translational set based at least in part on the first distance, the first angle of rotation, and the second angle of rotation;

sending the first beam of light from the coordinate measurement device to the first retroreflector;

receiving by the coordinate measurement device the second beam of light from the first retroreflector;

determining by the device processor the orientational set and the translational set, the translational set based at least in part on the second beam of light;

selecting the first information to be conveyed, the first information selected from the group consisting of a position on the object, a plurality of positions on the object, a direction indicated by a moving pattern, a message that includes one or more symbols or alphanumeric characters, a hidden feature, a measured object characteristic, a modeled characteristic, a magnified representation of surface characteristics, a pattern having meaning according to a rule, and combinations thereof;

determining the first pattern of light corresponding to the first information;

storing the first pattern; and

projecting from the projector the first pattern of light onto the object based at least in part on the translational set and the orientational set.

2. The method of claim 1, wherein the step of determining the first pattern of light further includes a step of determining a transformation relationship between an object frame of reference for the object and a frame of reference selected from the group consisting of the device frame of reference and the target-projector frame of reference.

3. The method of claim 2, wherein the step of determining the first pattern of light further includes measuring with the coordinate measurement device three dimensional coordinates of at least three non-collinear points on the object.

4. The method of claim 2, wherein:

the step of selecting the first information to be conveyed further includes selecting a first position on the object where an assembly operation is to be performed or a first plurality of positions on the object where an assembly operation is to be performed; and

the step of projecting from the projector the first pattern further includes projecting the first pattern to the first position or the first plurality of positions.

5. The method of claim 4, wherein, in the step of selecting the first information to be conveyed, the assembly operation to be performed is selected from the group consisting of drilling, scribing, removing surface material, adding surface material, attaching a component, applying adhesive, applying a coating, applying a label, cleaning, and combinations thereof.

6. The method of claim 2, wherein:

the step of selecting the first information to be conveyed further includes directing measurements with the dimensional measurement device; and

the step of projecting from the projector the first pattern further includes projecting a pattern of light in the direction at which a dimensional measurement is to be made.

7. The method of claim 1, wherein the step of selecting the first information to be conveyed further includes selecting a pattern having meaning according to a rule from among a plurality of rules, the plurality of rules configured to be available to the user in written or displayed form.

8. The method of claim 2, wherein:

the step of selecting the first information to be conveyed further includes selecting a hidden feature, the hidden feature obtained from drawings or measured data; and

the step of projecting from the projector the first pattern further includes projecting the first pattern over a portion of a first area, the first area being an area of the object for which the hidden feature information is available.

9. The method of claim 2, wherein:

the step of selecting the first information to be conveyed further includes selecting measured object characteristics that include measured error, the measured error taken as the difference between measured dimensional values and nominal or specified dimensional values; and

the step of projecting from the projector the first pattern further includes projecting the first pattern over a portion of a first area, the first area being an area of the object for which the measured object characteristics are available.

10. The method of claim 2, wherein:

the step of selecting the first information to be conveyed further includes selecting measured object characteristics, the measured object characteristic selected from the group consisting of temperature values, ultrasound values, microwave values, millimeter-wave values, X-ray values, radiological values, chemical sensing values, and combinations thereof; and

the step of projecting from the projector the first pattern further includes projecting the first pattern over a portion of a first area, the first area being an area of the object for which the measured object characteristics are available.

11. The method of claim 2, wherein:

the step of selecting the first information to be conveyed further includes selecting modeled characteristics, the modeled characteristics including values obtained from finite-element analysis; and

the step of projecting from the projector the first pattern onto the object further includes projecting the first pattern over a portion of a first area, the first area being an area of the object for which the modeled characteristics are available.

12. The method of claim 1, wherein the step of selecting the first information to be conveyed includes selecting the first information based at least in part on a gesture given by the user and detected and interpreted by the coordinate measurement device or by a computer attached to the coordinate measurement device.

13. The method of claim 1, wherein the step of providing the first target projector further includes providing a fixture rigidly attached to the body, the fixture stationary with respect to the device frame of reference.

17. The method of claim 1, wherein the step of providing the first target projector further includes providing a movable carrier, the first target projector attached to the movable carrier.

18. The method of claim 17, wherein, in the step of providing the first target projector, the movable carrier is a robot.

19. The method of claim 2, wherein, in the step of providing the coordinate measurement device and the first target projector, the first target projector further includes a tactile probe configured to measure three-dimensional coordinates of a first point on a surface of the object, the measured three-dimensional coordinates based at least in part on the translational set and the orientational set.

20. The method of claim 19, wherein the step of projecting from the projector the first pattern of light onto the object further includes indicating a position to be measured on the object surface, the indication given by projecting the first pattern of light onto the object surface.

21. The method of claim 1, further including steps of:

incorporating a pattern into the first retroreflector;

providing a second optical system including a second lens and a second photosensitive array, the second lens configured to form a second image of at least a portion of the first retroreflector on the second photosensitive array;

converting the second image into a second digital data set; and

calculating the orientational set based at least in part on the second digital data set.

22. The method of claim 1, further including steps of:

providing the first target projector with a speaker, the speaker configured to give audio messages;

selecting second information to be conveyed;

determining a first audio message corresponding to the second information; and

issuing the first audio message from the speaker.

23. The method of claim 1, wherein:

the step of providing the first target projector further includes providing a second retroreflector rigidly attached to the body; and

the step of measuring the translational set and the orientational set with the coordinate measurement device further includes rotating the first target projector to acquire the second retroreflector with the first beam of light from the coordinate measurement device.

24. The method of claim 2, wherein the step of providing the first target projector further includes providing a handle on the first target projector.

25. The method of claim 1, wherein:

the step of selecting the first information to be conveyed further includes selecting a magnified representation of surface characteristics, the magnified representation of surface characteristics obtained from measurements; and

the step of projecting from the projector the first pattern onto the object further includes projecting the first pattern over a portion of a first area, the first area being an area of the object for which the magnified representation of surface characteristics is available.

14. A method of conveying first information to a user of a coordinate measurement device by projecting a first pattern with a first target projector, the method comprising steps of:

providing the first target projector having a target-projector frame of reference and including a body, a first retroreflector, and a projector, wherein the first retroreflector and projector are rigidly affixed to the body, the first target projector mechanically detached from the coordinate measurement device, the projector configured to project a pattern of light in two dimensions, the pattern of light forming a three-dimensional pattern of light when intercepted by a three-dimensional object;

sending the first beam of light from the coordinate measurement device to the first retroreflector;

receiving the second beam of light from the first retroreflector;

measuring the orientational set and the translational set, the translational set based at least in part on the second beam of light;

selecting the first information to be conveyed, the first information selected from the group consisting of a position on the object, a plurality of positions on the object, a direction indicated by a moving pattern, a message that includes one or more symbols or alphanumeric characters, a hidden feature, a measured object characteristic, a modeled characteristic, a magnified representation of surface characteristics, a pattern having meaning according to a rule, and combinations thereof;

determining the first pattern of light corresponding to the first information;

storing the first pattern;

projecting from the projector the first pattern of light onto the object based at least in part on the translational set and the orientational set;

wherein the step of providing the first target projector further includes providing a fixture rigidly attached to the body, the fixture stationary with respect to the device frame of reference; and

wherein the step of projecting from the projector the first pattern of light onto the object further includes continuing to project the first pattern of light onto the object when the coordinate measurement device no longer sends the first beam of light to the first retroreflector.

15. The method of claim 14, further including a step of measuring with the coordinate measurement device while the first target projector continues to project the first pattern of light onto the object.

16. The method of claim 14, further including:

providing a second target projector having a third retroreflector;

sending the first beam of light to the third retroreflector; and

returning the second beam of light from the third retroreflector to the coordinate measurement device.