Automated rotation mechanism for spherically mounted retroreflector

Patent metadata

Field	Value
Publication number	US-10655946-B2
Application number	US-201916259423-A
Country	US
Kind code	B2
Filing date	Jan 28, 2019
Priority date	Feb 12, 2018
Publication date	May 19, 2020
Grant date	May 19, 2020

Abstract

An apparatus includes a kinematic nest that supports an element having a spherical surface, a rotation mechanism that rotates the element, and processor that activates the rotation mechanism.

First claim

What is claimed is:

1. An apparatus comprising:
a kinematic nest operable to support a first element, the first element having a spherical surface;
a rotation mechanism operable to rotate the first element on the kinematic nest while the spherical surface retains contact with the kinematic nest; and
a first processor operable to activate the rotation mechanism.

2. The apparatus of claim 1 , wherein the first element includes an embedded retroreflector.

3. The apparatus of claim 2 , wherein the first element includes a spherically mounted retroreflector having a cube-corner retroreflector, the cube-corner retroreflector having a vertex centered on the spherical surface.

4. The apparatus of claim 1 , wherein the first element includes an embedded light source.

5. The apparatus of claim 1 , wherein a center of the spherical surface remains fixed relative to the kinematic nest while the first element is rotated on the kinematic nest.

6. The apparatus of claim 1 , wherein the rotation mechanism includes a motor and a first gear, the motor operable to rotate the first gear.

7. The apparatus of claim 1 , wherein the first gear is operable to rotate the first element.

8. The apparatus of claim 7 , wherein the first gear is operable to turn a second gear, the second gear being operable to rotate the first element.

9. The apparatus of claim 1 , wherein the apparatus further comprises an attachment bracket coupled to an adjustment mechanism, the attachment bracket being operable to hold the first element in a selected orientation, the selected orientation being based on an adjustment of the adjustment mechanism.

10. The apparatus of claim 2 , wherein the first processor is in communication with a second processor coupled to a laser tracker, the second processor sending a first signal to the first processor, the first processor operable to activate the rotation mechanism in response to the first signal.

11. The apparatus of claim 10 , wherein the first signal is a wireless signal or a wired signal.

12. The apparatus of claim 10 , wherein the apparatus is operable to receive the first signal and, in response, to activate or deactivate the rotation mechanism.

13. The apparatus of claim 12 , wherein the laser tracker includes a light source and a camera, light emitted by the light source being reflected by the retroreflector and received by the camera when the retroreflector is positioned within a first range of angles relative to the camera, the second processor sending the first signal to the first processor based at least in part on the reflected light received by the camera.

14. A method comprising:
providing a system processor;
providing a collection of at least three devices, each device having a kinematic nest, rotation mechanism, and device processor, each device coupled to a first element having a spherical surface, the rotation mechanism operable to rotate the first element on the kinematic nest while holding the spherical surface in contact with a kinematic nest; and
sending a signal from the system processor to the device processor in one of the devices and, in response, rotating the first element with the rotation mechanism.

15. The method of claim 14 , wherein, for each device in the collection, a center of the spherical surface remains fixed in space relative to the kinematic nest while the first element is being rotated.

16. The method of claim 14 , wherein each first element includes an embedded retroreflector.

17. The method of claim 16 , further comprising:
providing a laser tracker coupled to the system processor;
sending a signal from the system processor to each of the devices and, in response, rotating each retroreflectors to face the laser tracker;
measuring with the laser tracker first three-dimensional (3D) coordinates of each retroreflector; and
determining with the system processor a first pose of the laser tracker in relation to the at least three retroreflectors, the first pose based at least in part on the first 3D coordinates.

18. The method of claim 17 , further comprising:
changing the location of the laser tracker relative to the collection of devices from a first location to a second location;
sending a signal from the system processor to each device and, in response, rotating each retroreflector to face the laser tracker;
measuring with the laser tracker second 3D coordinates of each retroreflector; and
determining with the system processor a second pose of the laser tracker in relation to the at least three retroreflectors, the second pose based at least in part on the second 3D coordinates.

19. The method of claim 18 , further comprising:
measuring with the laser tracker initial 3D coordinates with the laser tracker in the first pose;
measuring with the laser tracker subsequent 3D coordinates with the laser tracker in the second pose; and
transforming with the system processor initial 3D coordinates and subsequent 3D coordinates to a common frame of reference based at least in part on the measured initial 3D coordinates, the measured subsequent 3D coordinates, the determined first pose, and the determined second pose.

20. The method of claim 19 , further comprising:
measuring with the laser tracker in the first pose starting 3D coordinates with a six degree-of-freedom (DOF) probe;
measuring with the laser tracker in the second pose ending 3D coordinates with the six DOF probe;
transforming with the system processor initial 3D coordinate and subsequent 3D coordinates to a common frame of reference based at least in part on the measured starting 3D coordinates, the measured ending 3D coordinates, the determined first pose, and the determined second pose.

21. The method of claim 14 , wherein each first element includes a light source or a reflective target.

Assignees

• Faro Tech Inc

Inventors

• Tahir Muhammad Umair
• Zweigle Oliver
• Bridges Robert E

Classifications

• G01S17/42

  Simultaneous measurement of distance and other co-ordinates (indirect measurement G01S17/46) · CPC title

• G01S17/66 Primary

  Tracking systems using electromagnetic waves other than radio waves · CPC title

• G01B5/004

  for measuring coordinates of points · CPC title

• G01S7/481

  Constructional features, e.g. arrangements of optical elements · CPC title

• G01B2210/58

  Wireless transmission of information between a sensor or probe and a control or evaluation unit · CPC title