Six degree-of-freedom laser tracker that cooperates with a remote sensor

• US 9,482,746 B2
• Filed: 04/11/2012
• Issued: 11/01/2016
• Est. Priority Date: 04/15/2011
• Status: Expired due to Fees

• Current Assignee: Faro Technologies Incorporated
• Original Assignee: Faro Technologies Incorporated
• Inventors: Bridges, Robert E.
• Primary Examiner(s): Cosimano, Edward
• Application Number:
  US13/443,951
• Publication Number:
  US 20120265479A1
• Time in Patent Office: 1,665 Days
• Field of Search: 702/135
• US Class Current: 1/1
• 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 measuring with a coordinate measurement device and a target sensor a sense characteristic and a surface set associated with the sense characteristic, the method including the steps of: providing the target sensor having a body, a first retroreflector, a sensor, and a sensor processor, providing the coordinate measurement device, 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; determining the surface set; sensing the sense characteristic; and saving the surface set and the sense characteristic.

Claims

1. A method of measuring with a coordinate measurement device and a target sensor a sense characteristic and a surface set associated with the sense characteristic, the surface set being three-dimensional coordinates of a point on the object surface in a device frame of reference, each surface set including three values, the device frame of reference being associated with the coordinate measurement device, the method comprising steps of:

providing the target sensor having a body, a first retroreflector, a sensor, and a sensor processor, wherein the first retroreflector and the sensor are rigidly affixed to the body, and the target sensor is mechanically detached from the coordinate measurement device, the target sensor configured to measure the sense characteristic, the sense characteristic being a value associated with a quantity measured by the sensor;

incorporating a pattern into the first retroreflector;

providing the coordinate measurement device, 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, and a control system, 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 retroreflector, 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 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 target sensor in the device frame of reference and the orientational set being values of three orientational degrees of freedom of the target sensor in the device frame of reference, the translational set and the orientational set defining a position and orientation of the target sensor in space, the translational set based at least in part on the second beam of light in space, the device processor further configured to determine the three-dimensional coordinates of the object surface point based at least in part on the determined translational set, the determined orientational set, the sensor position in the target frame of reference, and an object frame of reference for the object and the device frame of reference,

wherein the sensor processor and the device processor are jointly configured to determine the sense characteristic and the surface set, the surface set based at least in part on the translational set and the orientational set;

providing an 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 patterned retroreflector on the second photosensitive array;

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

forming the second image on the second photosensitive array, the second image including at least a portion of the pattern incorporated into the first retroreflector;

converting the second image into a second digital data set;

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

determining the surface set;

sensing the sense characteristic; and

saving the surface set and the sense characteristic.

2. The method of claim 1, wherein the step of determining the surface set is based at least in part on a coordinate measurement performed by the target sensor or by the measurement device.

3. The method of claim 1, wherein:

the step of sensing the sense characteristic further includes measuring a plurality of sense characteristics;

the step of measuring a translational set and an orientational set further includes measuring a plurality of translational sets and a plurality of orientational sets in correspondence with the plurality of sense characteristics;

the step of determining a surface set further includes determining a plurality of surface sets; and

the step of saving the surface set and sense characteristic further includes saving a plurality of surface sets and sense characteristics.

4. The method of claim 1, wherein:

the step of providing the target sensor 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 target sensor to acquire the second retroreflector with the first beam of light from the coordinate measurement device.

5. The method of claim 1, wherein the step of determining the surface set further includes:

determining the device frame of reference and the object frame of reference;

registering a CAD model of the object or measured three-dimensional data of the object to the device frame of reference;

projecting a vector from the device onto the registered CAD model; and

extracting the surface set.

6. The method of claim 5, wherein the step of determining the surface set further includes determining the device frame of reference and the object frame of reference by measuring at least three surface coordinates with the measurement device.

7. The method of claim 1, wherein the step of sensing the sense characteristic further includes sensing the characteristic wherein the characteristic is selected from the group consisting of a temperature, an ultrasound value, an electromagnetic wave value, a chemical characteristic value, a surface texture value, and combinations thereof.

8. The method of claim 7, further including a step of illuminating the target object with a source of illumination, the source of illumination selected from the group consisting of ultrasound and electromagnetic radiation.

9. The method of claim 7, wherein the step of sensing the sense characteristic further includes sensing a first temperature value of the object with a temperature sensor brought into contact with the object, the first temperature value being the characteristic and the temperature sensor being the sensor.

10. The method of claim 7, wherein the step of sensing a sense characteristic further includes sensing an electromagnetic wave value wherein the electromagnetic wave value includes an amplitude or a power of the electromagnetic wave.

11. The method of claim 7, wherein the step of sensing a sense characteristic further includes sensing an electromagnetic wave value wherein the electromagnetic wave value includes a wavelength or a frequency of the electromagnetic wave.

12. The method of claim 7, wherein the step of sensing a sense characteristic further includes sensing an electromagnetic wave value wherein the electromagnetic wave is selected from the group consisting of visible light, infrared light, ultraviolet light, and combinations thereof.

13. The method of claim 12, wherein the step of sensing a sense characteristic further includes sensing an electromagnetic wave value wherein the electromagnetic wave value is optical power or surface reflectance.

14. The method of claim 7, wherein the step of sensing the sense characteristic further includes sensing a first temperature value of the object with a non-contact temperature sensor, the first temperature value being the characteristic and the non-contact temperature sensor being the sensor.

15. The method of claim 14, wherein the step of sensing the sense characteristic further includes sensing the temperature value with an infrared temperature sensor.

16. The method of claim 14, wherein:

the step of sensing the sense characteristic further includes sensing a plurality of temperatures with a first sensor array assembly, the first sensor array assembly including a first lens and a first sensor array, the first lens having a first lens perspective center and a first lens optical axis, the first lens optical axis passing through the first lens perspective center, the first sensor array including a plurality of first sensor pixels, each first sensor pixel responding to a pixel temperature of the object at a pixel object position, each pixel object position determined by an intersection of a pixel vector with the object surface, the pixel vector for each first sensor pixel fixed in relation to the first lens perspective center and the first lens optical axis;

the step of determining the surface set further includes determining a plurality of surface sets associated with a plurality of sensed characteristics; and

the step of saving the surface set and the sensed characteristic further includes saving the plurality of surface sets and the sensed characteristics.

17. The method of claim 16, wherein the step of sensing a sense characteristic further includes sensing an amplitude or a power of the electromagnetic wave, the electromagnetic wave selected from the group consisting of an RF wave, a microwave, a millimeter wave, a terahertz wave, and combinations thereof.