JP2016212098A - Scanner tracker composite device including focus adjustment mechanism - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical measuring instrument that allows operators to select an operation mode from a plurality of operation modes.SOLUTION: A three-dimensional (3D) coordinate measuring instrument combines functions of a tracker part 34 and scanner part 36. The function of the tracker part 34 is configured to send light to a retroreflector and determine a distance to the retroreflector on the basis of reflection light. The function of the tracker part 34 is configured to track the retroreflector as it moves and determine 3D coordinates of the retroreflector. The scanner part 36 is configured to send a light beam to a point on an object surface and determine 3D coordinates of the point. In addition, the scanner part 36 is configured to include an adjustable focus adjustment mechanism 39 causing the light beam to be adjustably focused.SELECTED DRAWING: Figure 21

Description

  The present invention relates to an optical measurement instrument that measures dimensional coordinates, and more particularly to a non-contact optical measurement instrument that includes a plurality of optical devices for measuring an object.

CROSS REFERENCE TO RELATED APPLICATIONS This application is a US patent application Ser. No. 13/765 entitled “Multi-Mode Optical Measurement Device and Method of Operation” filed on Feb. 12, 2013. , 014, which is hereby incorporated by reference in its entirety.

  Non-contact optical measurement equipment may be used to measure the coordinates of a point on an object. One type of optical measurement instrument measures the three-dimensional (3D) coordinates of a point by sending a laser beam to that point. The laser beam may impinge directly on that point or impinge on a retro-reflector target that contacts that point. In either case, the instrument determines the coordinates of the point by measuring the distance to the target and two angles. The distance is measured by a distance measuring device such as an absolute distance meter or an interferometer. The angle is measured by an angle measuring device such as an angle encoder. A gimbal beam steering mechanism in the instrument directs the laser beam to the point of interest.

  A laser tracker is a specific type of coordinate measuring instrument that tracks a retro-reflector target with one or more laser beams it emits. Optical measuring instruments closely related to the laser tracker are a laser scanner and a total station. Laser scanners step scan a point on a surface with one or more laser beams. This picks up the light scattered from the surface and specifies the distance and two angles from this light to each point. Total stations are most often used in the surveying field and may be used to measure the coordinates of diffusely scattered (non-cooperative) or retroreflector type (cooperative) targets.

  Laser trackers operate by sending a laser beam to a retroreflector target, which is used to measure the coordinates of a particular point. A common type of retro-reflector target is a spherically mounted retroreflector (SMR), which includes a cube corner retro-reflector embedded within a metal sphere. The cube corner retro-reflector includes three mirrors that are perpendicular to each other. The vertex, the common intersection of the three mirrors, is positioned at the center of the sphere. The mechanical relationship of the cube corner placement within the sphere to the measurement point is known (ie, the vertical distance from the apex to any surface on which the SMR is mounted remains constant as the SMR rotates). Therefore, the position of the measurement point can be specified. As a result, the laser tracker can measure the 3D coordinates of a surface by following its position as the SMR moves on the surface. In other words, a laser tracker can fully characterize the 3D coordinates of a surface if it measures only three degrees of freedom (one radial distance and two angles).

  One type of laser tracker includes only an interferometer (IFM) and does not have an absolute distance meter (ADM). If the object blocks the path of the laser beam from one of these trackers, the IFM loses its distance reference. The operator can then continue the measurement after tracking the retroreflector to a known position and resetting the reference distance. A workaround for this limitation is to include the ADM in the tracker. The ADM can measure distance by aiming.

  Since the tracker stays at a certain point, it is desirable to constrain the laser power to keep the desired classification within the IEC 60825-1 standard. Therefore, it is desirable for the tracker to operate with a low laser power. In addition to clearly defining the measurement points, SMR returns most of the laser power. In contrast, the laser scanner may be configured to move continuously, thereby achieving the desired IEC 60825-1 classification because the total energy deposited on a portion of the person in the operating area is small. it can. Therefore, laser scanners operate at higher laser power levels and can operate with non-cooperative targets, but are generally less accurate and shorter in distance than laser trackers.

  The laser scanner also sends a laser beam toward the object. Since the laser tracker interacts with the operator (via the retroreflector target), it is desirable that the laser be visible. However, the laser scanner may operate at other wavelengths, such as infrared or visible, because the light beam may not be visible to the operator. The laser scanner receives light reflected from the object and determines, in part, the distance to a point on the object based on the time of flight until the light strikes the object and returns to the scanner. Some laser scanners can rotate continuously around the zenith axis while simultaneously rotating the laser beam around the azimuth axis to identify the coordinates of points in the area around the laser scanner. Another laser scanner directs the light beam to a single point or in a predetermined pattern, such as a raster pattern.

  It should be understood that a laser scanner can obtain the coordinates of multiple points much faster than a laser tracker. However, laser trackers measure distances with greater accuracy. In addition, since the laser tracker remains at a specific point, measurements are generally integrated into a fraction of a second to reduce electronic and atmospheric turbulence noise. Laser scanners typically measure millions of points per second, so measurements are typically made on the order of microseconds or a fraction of a microsecond. Therefore, noise from electronic components and atmospheric turbulence can be much greater in a scanner.

US Pat. No. 7,327,446 US Pat. No. 7,701,559 US Patent Application Publication No. 2011/0032509

  Therefore, existing non-contact optical measuring instruments are suitable for their intended purpose, but still need improvement, especially optical measuring instruments that allow an operator to select an operation mode from a plurality of operation modes. Need to provide.

  According to one aspect of the present invention, the coordinate measuring instrument is a first absolute distance meter including an optical transmission system, a first light source, a first photodetector, and a first electric circuit, The one light source is configured to send the first light to the retro-reflector target through the light transmission system, and the first light detector is further responsive to the first light being reflected by the retro-reflector target. Generating an electrical signal and transmitting the first electrical signal to the first electrical circuit, the first electrical circuit having a first distance from the coordinate measuring instrument to the retroreflector target, A first absolute rangefinder configured to determine at least in part based on the first electrical signal; a second light source; an adjustable focus adjustment mechanism; a second photodetector; and a second A second absolute distance meter including an electric circuit, The second light source is configured to send a second light to the object surface through the adjustable focus adjustment mechanism light transmission system, and the second light detector is reflected by the object surface and passed through the light transmission system. The second light detector is further configured to generate a second electrical signal in response to the second light being reflected by the object surface and to generate the second electrical signal. Configured to transmit to a second electrical circuit, wherein the second electrical circuit determines a second distance from the coordinate measuring instrument to the object surface based at least in part on the second electrical signal A second absolute distance meter as configured, a structure operatively coupled to the optical transmission system, the first absolute distance meter and the second absolute distance meter, and rotating the structure about the first axis; A first motor configured to be operatively coupled to the structure A first angle converter configured to measure a first rotation angle about a first axis and to rotate the structure about a second axis; A second motor configured with a second motor such that the second axis is substantially perpendicular to the first axis, and a second angle operatively coupled to the structure A transducer, a second angle transducer configured to measure a second rotation angle about a second axis, and a position detector, emitted by a coordinate measuring instrument and retroreflector A position detector configured to receive a portion of the radiation reflected by the target and configured to generate a third electrical signal based on a position where at least a portion of the radiation strikes the position detector; A processor to operate in a first mode and a second mode A processor having a computer readable medium configured to track a retroreflector target based at least in part on a third electrical signal; and a first of the retroreflector target The three-dimensional coordinates are determined at least in part by a first rotation angle to the retroreflector target at the first position, a second angle of the retroreflector target at the first position, and a first of the retroreflector target at the first position. The second mode includes directing the second light to the object surface, and a second three-dimensional coordinate of a point on the object surface at least in part. The first rotation angle to that point on the object, the second rotation angle of that point on the object surface and the second distance of that point on the object surface Comprising the step of determining by Zui, second mode, further comprising the step of adjusting the adjustable focus adjustment mechanism.

  In the coordinate measuring instrument of the present invention, the optical transmission system has an inner optical path and an outer optical path, the outer optical path is coaxial with the inner optical path and is outside the inner optical path, and the first photodetector is a retroreflector target. The second light detector is configured to receive the first light reflected and passed through the inner optical path of the light transmission system, and the second light detector is reflected by the object surface and passed through the outer light path of the light transmission system. It is also preferable that it is comprised so that it may receive.

  In the coordinate measuring instrument of the present invention, it is also preferable to emit the second light along the spiral path by rotating the structure in one direction, and the optical transmission system is reflected by the object surface. It is also preferable to further include an annular opening positioned to receive a portion of the second light that has been produced.

  In the coordinate measuring instrument of the present invention, it is also preferable that the processor is configured to emit the first light when the second absolute distance meter emits the second light.

  In the coordinate measuring instrument of the present invention, the wavelength of the first light is preferably about 700 nanometers, and the wavelength of the second light is also preferably about 1550 nanometers. .

  According to another aspect of the invention, a coordinate measuring instrument includes a structure, a first motor configured to rotate the structure about a first axis, and a first operatively coupled to the structure. A first angle transducer configured to measure a first rotation angle about a first axis and a structure configured to rotate the structure about a second axis A second motor, wherein the second axis is substantially perpendicular to the first axis, and the projection of the second axis intersects the projection of the first axis at the gimbal point. A second angle converter operably coupled to the second motor and the structure, the second angle converter configured to measure a second rotation angle about the second axis An optical transmission system operatively coupled to the structure, and a first absolute rangefinder operatively coupled to the structure, the first light source and the first Including a detector and a first electrical circuit, wherein the first light source transmits the first light through the first optical transmission system along a portion of the first line extending from the gimbal point to the retro-reflector target. Configured, the first line is perpendicular to the first axis, the first photodetector is configured to receive the first light reflected by the retroreflector target and passed through the optical transmission system; The photodetector is further configured to generate a first electrical signal in response to the first light reflected by the retroreflector target and to transmit the first electrical signal to the first electrical circuit. And the first electrical circuit is configured to determine a first distance from the coordinate measuring instrument to the retroreflector target based at least in part on the first electrical signal. And the structure An operably coupled second absolute distance meter comprising a second light source, an adjustable focus adjustment mechanism, a second photodetector and a second electrical circuit, wherein the second light source is adjustable; Configured to send a second light along a portion of the second line extending from the gimbal point to the object surface through the focus adjustment mechanism and the light transmission system, the second line being perpendicular to the first axis The second line is different from the first line, the second light detector is configured to receive the second light reflected by the object surface and passed through the light transmission system. The apparatus is further configured to generate a second electrical signal in response to the second light reflected by the object surface and to transmit the second electrical signal to the second electrical circuit, The electrical circuit of the second electrical signal, at least in part, from the coordinate measuring device to the object surface. A second absolute rangefinder, such as configured to determine on the basis of the signal, and a position detector to receive a portion of the radiation emitted by the coordinate measuring instrument and reflected by the retro-reflector target A position detector configured to generate a third electrical signal based at least in part on a position where a portion of the light radiation strikes the position detector; and a processor, And a processor having a computer readable medium configured to operate in a second mode, wherein the first mode is based at least in part on the third electrical signal based on the retroreflector target. Tracking and the first three-dimensional coordinates of the retroreflector target at least partially in the first position of the retroreflector target at the first position. Determining based on the rotation angle and the second rotation angle to the retro-reflector target at the first position and the first distance of the retro-reflector target at the first position, the second mode comprising: Rotating around one axis and the second three-dimensional coordinates of the point on the object surface at least partially to the first rotation angle to that point on the object surface and to that point on the object surface Determining based on the second rotation angle and a second distance of the point on the object surface, the second mode further comprising adjusting the adjustable focus adjustment mechanism.

  In the coordinate measuring instrument of the present invention, the first line extends in the first radial direction, the second line extends in the second radial direction, and an angle is formed between them, and the angle is 5 degrees to It is preferable that the angle is 180 degrees, and that the angle is 90 degrees.

  According to another aspect of the present invention, the coordinate measuring instrument is a first absolute distance meter including an optical transmission system, a first light source, a first photodetector, and a first electric circuit, One light source is configured to send a first light through a light transmission system to a retroreflector target, and a first light detector reflects the first light reflected by the retroreflector target and passed through the light transmission system. Configured to receive, the first photodetector further generates a first electrical signal in response to the first light reflected by the retroreflector target, and the first electrical signal is the first electrical signal. Configured to transmit to an electrical circuit, wherein the first electrical circuit is configured to determine a first distance from the coordinate measuring instrument to the retroreflector target based at least in part on the first electrical signal. ing A second absolute distance meter including a first absolute distance meter, a second light source, an adjustable focus adjustment mechanism, a second photodetector and a second electrical circuit, wherein the second light source is: The second light detector is configured to send the second light to the object surface through the adjustable focus adjustment mechanism and the light transmission system, and the second light detector reflects the second light reflected by the object surface and passed through the light transmission system. Configured to receive, the second photodetector further generates a second electrical signal in response to the second light being reflected by the object surface, and the second electrical signal is transmitted to the second electrical signal. Configured to transmit to the circuit, and the second electrical circuit is configured to determine a second distance from the coordinate measuring device to the object surface based at least in part on the second electrical signal Such as the second absolute distance meter, the optical transmission system and the first absolute distance meter and the second A structure that is operatively coupled to the absolute rangefinder, including a mirror mounted for rotation, wherein the mirror is disposed in the optical path of the first light and the second light; A first motor configured to rotate the structure about the first axis and a first angle transducer operatively coupled to the structure, the first angle converter about the first axis A first angle transducer configured to measure a rotation angle of the second motor and a second motor configured to rotate the mirror about the second axis, the second axis being the first A second motor, substantially perpendicular to the axis of the second, and a second angle transducer operatively connected to the mirror, measuring a second rotation angle about the second axis A second angle transducer configured as described above, and a position detector, emitted by a coordinate measuring instrument, and retro-reflector A position detector configured to receive a portion of the radiation reflected by the target and configured to generate a third electrical signal based at least in part on a position where the portion of the radiation strikes the position detector And a processor having a computer readable medium configured to operate in a first mode and a second mode, wherein the first mode at least partially includes the retroreflector target Tracking based on the third electrical signal to the first three-dimensional coordinates of the retroreflector target, at least in part, the first rotation angle and the first position to the retroreflector target at the first position Based on the second rotation angle to the retroreflector target at the first position and the first distance of the retroreflector at the first position. And the second mode comprises rotating the structure about the first axis and a second three-dimensional coordinate of a point on the object surface at least partially in its position on the object surface. Including a step of determining based on a first rotation angle up to and a second rotation angle up to that position on the object surface and a second distance of that point on the object surface, the second mode being adjustable The method further includes adjusting the focus adjustment mechanism.

  In the coordinate measuring instrument of the present invention, in the second mode, the first motor rotates the structure at the first speed, the second motor rotates the mirror at the second speed, and the second speed is It is also preferred that it is faster than the first speed, and the second mode is also suitable as including the step of rotating the structure in one direction around the first axis.

  These and other advantages and features will become more apparent when the following description is read in conjunction with the drawings.

  The subject matter regarded as the invention is particularly pointed out and distinctly claimed in the claims at the end of the specification. These and other features and advantages of the present invention will become apparent from the following detailed description when read in conjunction with the accompanying drawings.

  The present invention can provide an optical measuring instrument that allows an operator to select an operation mode from a plurality of operation modes.

1 is a perspective view of an optical measurement device according to an embodiment of the present invention. 2 is a partial perspective view of the optical measurement instrument of FIG. 1 showing the position of a tracker portion and a scanner portion including sensors in the device. 2 is a block diagram of an electrical and computing system for the device of FIG. FIG. 2 is a schematic diagram of the apparatus of the payload portion of FIG. 1 including a block diagram of an optical measurement instrument according to an embodiment of the present invention. 2 is an absolute distance meter (ADM) for the laser track portion of the optical measurement instrument of FIG. It is a block diagram of the fiber network shown in FIG. It is a block diagram of the fiber network shown in FIG. It is a block diagram of the retro reflector shown in FIG. It is another block diagram of the retro reflector shown in FIG. It is another block diagram of the fiber network shown in FIG. It is the schematic of the apparatus of FIG. 1 which shows the optical axis when the light from a tracker and a scanner is projected. FIG. 2 is a perspective view of the apparatus of FIG. 1 showing another embodiment of a scanner portion and a tracker portion. FIG. 2 is a perspective view of the apparatus of FIG. 1 showing another embodiment of a scanner portion and a tracker portion. FIG. 2 is a perspective view of the apparatus of FIG. 1 showing another embodiment of a scanner portion and a tracker portion. 1 is a schematic diagram of an optical measurement instrument in a first mode of operation according to an embodiment of the present invention. FIG. It is the schematic of the 1st optical measuring instrument of a 2nd operation mode. It is a flowchart which shows the step which operates an optical measuring instrument. It is a flowchart which shows the step which operates an optical measuring instrument. FIG. 2 illustrates an apparatus that emits tracker light and scanner light in two different directions from a scanner-tracker according to an embodiment. 1 is a schematic diagram of a scanner-tracker device that directs a light beam from a tracker to a retro-reflector using a rotating mirror, according to an embodiment of the invention. FIG. FIG. 2 is a schematic diagram of the apparatus payload portion of FIG. 1 including a block diagram of an optical measurement instrument according to an embodiment of the present invention. It is the schematic of the apparatus of FIG. 1 which shows the optical axis when the light from a tracker part and a scanner part is projected. 1 is a schematic diagram of an optical measurement instrument in a first mode of operation according to an embodiment of the present invention. FIG. FIG. 2 is a schematic diagram of the optical measurement instrument of FIG. 1 in a second operation mode. FIG. 2 illustrates an apparatus that emits tracker light and scanner light in two different directions from a scanner-tracker according to an embodiment. FIG. 6 is a schematic diagram of an adjustable focus adjustment mechanism according to an embodiment.

  In the detailed description, an embodiment of the present invention will be described as an example together with advantages and features with reference to the drawings.

  Embodiments of the present invention provide an optical measurement instrument that can operate as both a laser tracker and a laser scanner. This has the advantage of being able to do both higher-precision measurements, usually using collaborative targets that the operator has in hand, and higher-speed (usually) lower-precision measurements that are usually not actively supported by the operator. I will provide a. These two modes of operation are provided in a single integrated device.

  Referring now to FIGS. 1-2, a coordinate measuring device 30 that provides a plurality of operating modes is shown. The device 30 has a housing 32, which includes a tracker portion 34 that supports a laser tracking function and a scanner portion 36 that supports a scanner function. The exemplary gimbal beam steering mechanism 38 includes a zenith carriage 42 that is mounted on an azimuth base 40 and rotates about an azimuth axis 44. The payload structure 46 is mounted on a zenith carriage 42 that rotates about a zenith shaft 48. The zenith axis 48 and the azimuth axis 44 intersect perpendicularly at the gimbal point 50 within the device 30. The gimbal point 50 is generally the origin of distance and angle measurements. One or more light beams 52 effectively pass through the gimbal point 50. The emitted light beam is directed in a direction perpendicular to the zenith axis 48. In other words, the light beam 52 is in a plane that is substantially perpendicular to the zenith axis 48 and includes the azimuth axis 44. The light beam 52 is directed in the desired direction by rotating the payload structure 46 about the zenith axis 48 and rotating the zenith carriage 42 about the azimuth axis 44.

  A zenith motor 51 and a zenith angle encoder 54 are disposed within the housing 32 and are attached to a zenith machine shaft that is aligned with the zenith shaft 48. An azimuth motor 55 and an azimuth angle encoder 56 are also disposed within the instrument 30 and are attached to an azimuth machine shaft that is aligned with the azimuth shaft 44. Zenith motor 51 and azimuth motor 55 operate to rotate payload structure 46 about axes 44 and 48 simultaneously. As will be described in detail later, in the scanner mode, the Zenith motor 51 and the azimuth motor 55 are each operated in a single direction, and as a result, the scanner light follows a continuous path that does not reverse the direction. Zenith and azimuth angle encoders 54 and 56 measure zenith and azimuth rotation angles with relatively high accuracy.

  The light beam 52 travels to the target 58, which reflects the light beam 52 back to the instrument 30. Target 58 may be a non-cooperative target, such as object surface 58 '. Alternatively, the target 58 may be a retro-reflector, for example, a spherically mounted retroreflector (SMR). By measuring the radial distance between the gimbal point 50 and the target 58, the rotation angle around the zenith axis 48, and the rotation angle around the azimuth axis 44, the position of the target 58 is within the spherical coordinate system of the instrument 30. May be found at. As described in more detail herein, the instrument 30 includes one or more mirrors, lenses, or apertures that define an optical transmission system that directs and receives light.

  The light beam 52 may include one or more light wavelengths, such as visible and infrared wavelengths. It should be understood that although the embodiments herein are described with respect to a gimbal beam steering mechanism 38, other types of steering mechanisms can be used. In other embodiments, for example, the mirror may be rotated around the azimuth and zenith axes 44,48. In other embodiments, a galvo mirror may be used to guide the light. Similar to the exemplary embodiments, these other embodiments (eg, galvo mirrors) may be used to direct light in a single direction along a path that does not reverse direction, as described in more detail below. .

  In one embodiment, the magnetic nest 60 may be disposed on the azimuth base 40. The magnetic nest 60 resets the tracker to a “home position” such as SMRs of different sizes, for example 1.5, 7/8, and 0.5 inch (38.1 mm, 22.225 mm, 12.7 mm) SMRs. For use with the tracker portion 34. A retro-reflector on the device may then be used to reset the tracker portion 34 to a reference distance. In addition, a mirror (not shown) may be used with a retroreflector to allow self-correction to be performed, which is described in US Pat.

  Now referring to FIG. 3, an exemplary controller 64 for controlling the operation of the device 30 is shown. The controller 64 includes a distributed processing system 66, a temperature sensor 68, a processing system for the personal digital assistant 72, an external computer 74, and other network components 76, shown here as clouds. An exemplary embodiment of the distributed processing system 66 includes a master processor 78, payload functional electronics unit 80, azimuth encoder electronics 82, Zenith encoder electronics 86, display and user interface (UI) 88, and removable. Storage hardware 90, radio frequency identification (RFID) wireless electronic component 92, and antenna 94 are included. The payload function electronic component unit 80 includes, for example, a scanner electronic component 96, a camera electronic component 98 (for the color camera 168 in FIG. 11), an ADM electronic component 100, a position detector (PSD) electronic component 102, a level electronic component 104, and the like. Includes many functions. Some or all of the dependent functions in the payload function electronic component unit 80 have at least one processing unit, which may be, for example, a digital signal processor (DSP) or a field programmable gate array (FPGA).

  Many types of peripheral devices can be used, for example, a temperature sensor 68 and a portable information terminal 72. The portable information terminal 72 may be a cellular telecommunication device such as a smartphone. The device 30 may communicate with peripheral devices in a variety of ways, such as by wireless communication through an antenna 94, by a video system such as a camera, and by reading the distance and angle from the laser tracker to a collaborative target. The peripheral device may include a processor. In general, where the terms scanner electronics, laser tracker electronics, or measuring instrument processor are used, this shall include available external computers and cloud support.

  In certain embodiments, another communication medium or bus extends from the master processor 78 to each of the payload functional electronics units 80, 82, 86, 88, 90, 92. Each communication medium may have, for example, three serial lines including a data line, a clock line, and a frame line. The frame line indicates whether the electronic component unit should pay attention to the clock line. If it indicates that care should be taken, the electronic component unit reads the current value of the data line with each clock signal. The clock signal may correspond to, for example, a rising edge of a clock pulse. In one embodiment, the information is transmitted in the form of packets on the data line. In other embodiments, each packet includes an address, a numeric value, a data message, and a checksum. The address indicates where in the electronic component unit the data message should be directed. The location may correspond to, for example, a processor subroutine in the electronic component unit. The numerical value indicates the length of the data message. The data message includes data or instructions executed by the electronic component unit. The checksum is a numerical value used to minimize the probability of occurrence of errors in the data transmitted on the communication line.

  In one embodiment, the master processor 78 sends information packets on the bus line 106 to the payload functional electronics unit 80, on the bus line 108 to the azimuth encoder electronics 82, on the bus line 110 to the Zenith encoder electronics 86, to the bus 112. Transmit to display and UI electronics 88 above, to removable storage hardware 90 on bus 114, and to RFID and wireless electronics 92 on bus 116.

  In certain embodiments, the master processor 78 also transmits a synchronization pulse on each of the electronic component units simultaneously on the sync bus 118. The sync pulse provides a way to synchronize the numerical values collected by the instrument 30 measurement function. For example, the azimuth encoder electronics 82 in the Zenith encoder electronics 86 latches the encoder value as soon as a sync pulse is received. Similarly, payload functional electronic component unit 80 latches data collected by electronic components housed within the payload structure. All ADMs and position detectors latch data when a sync pulse is applied. In most embodiments, the camera and inclinometer collect data at a rate slower than the sync pulse rate, but data may be latched every multiple of the sync period.

  In one embodiment, azimuth encoder electronics 82 and zenith encoder electronics 86 are separated from each other and from payload functional electronics unit 80 by a slip ring (not shown). If slip rings are used, the bus lines 106, 108, 110 may be separate buses. The distributed processing system 66 may communicate with the external computer 74, or may provide communication within the device 30, a display, and a UI function. The device 30 communicates with an external computer 74 over a communication link 120, such as an Ethernet line or a wireless connection. Device 30 may also communicate over communication link 122 with other elements represented by cloud 76, which includes one or more electrical cables, such as an Ethernet cable, or one or more wireless connections. You may go out. Element 76 may be other three-dimensional test equipment, such as an articulated arm CMM, which may be moved by equipment 30. Communication link 124 between external computer 74 and element 76 may be wired or wireless. An operator sitting in front of the external computer 74 connects to the Internet, represented by cloud 76, via an Ethernet or wireless link, which connects them to the master processor 78 over the Ethernet or wireless link. Connect with. In this way, the user can control the operation of a remote device, such as a laser tracker.

  Referring now to FIG. 4, one embodiment of a payload structure 46 within the instrument 30 having a tracker portion 34 and a scanner portion 36 is shown. The tracker portion 34 and the scanner portion 36 are integrated to emit light from the tracker portion 34 and the scanner portion 36 on a substantially common inner optical path, which is illustrated in FIGS. It is shown. However, although the light emitted by tracker portion 34 and scanner portion 36 travels on a substantially common optical path, in one embodiment, the light beams from tracker portion 34 and scanner portion 36 are emitted at different times. In other embodiments, the beams are emitted simultaneously.

  The tracker portion 34 includes a light source 126, an isolator 128, a fiber network 136, an ADM electronics 140, a fiber injection system 130, a beam splitter 132, and a position detector 134. In some embodiments, the light source 126 emits visible light. The light source may be, for example, a red or green diode laser or a vertical cavity surface emitting laser. The isolator may be a Faraday isolator, an attenuator, or any other suitable device that can sufficiently reduce the amount of light returned to the light source 126. Light from the isolator 128 travels to the fiber network 136. In one embodiment, the fiber network 136 is the fiber network shown in FIG. 6, which will be described in more detail below. The position detector 134 is arranged to receive a portion of the radiation emitted by the light source 126 and reflected by the target 58. The position detector 134 is configured to provide a signal to the controller 64. The signal is used by the controller 64 to operate the motors 51, 55 to direct the light beam 52 to track the target 58.

  Some of the light incident on the fiber network 136 is transmitted over the optical fiber 138 to the reference channel of the ADM electronic component 140. Other portions of the light incident on the fiber network 136 pass through the fiber network 136 and the beam splitter 132. The light reaches the dichroic beam splitter 142, which is configured to transmit light at the wavelength of the ADM light source. Light from the tracker portion 34 exits from the payload structure 46 through the opening 146 along the optical path 144. Light from tracker portion 34 travels along optical path 144, is reflected by target 58, returns along optical path 144, and reenters payload structure 46 through opening 146. This return light passes through the dichroic beam splitter 142 and returns to the tracker portion 34. The first portion of the return light passes through the beam splitter 132 and enters the fiber injection system 130 and enters the fiber network 136. Some of the light passes through the optical fiber 148 and enters the measurement channel of the ADM electronics 140. The second part of the return light is reflected by the beam splitter 132 and enters the position detector 134.

In one embodiment, the ADM electronic component 140 is that shown in FIG. The ADM electronic component 140 includes a frequency reference 3302, a synthesizer 3304, a measurement detector 3306, a reference detector 3308, a measurement mixer 3310, a reference mixer 3312, conditioning electronic components 3314, 3316, 3318, 3320, N A frequency division prescaler 3324 and an analog-to-digital converter (ADC) 3322 are included. The frequency reference may be, for example, a thermostat crystal oscillator, for example, sending a reference frequency f _{REF of} 10 MHz to the synthesizer, which has two electrical signals: one signal at frequency f _RF and two signals at frequency f _LO. Is generated. A signal of frequency f _RF enters the light source 126. Two signals of frequency f _LO enter a measurement mixer 3310 and a reference mixer 3312. Light from optical fibers 138 and 148 is incident on the reference and measurement channels, respectively. The reference detector 3308 and the measurement detector 3306 convert the optical signal into an electrical signal. These signals are conditioned by conditioning electronics 3316 and 3314, respectively, and transmitted to mixers 3312 and 3310, respectively. The mixer generates a signal with a frequency f _IF equal to the absolute value f _LO −f _RF . The signal at frequency f _RF may be a relatively high frequency, eg 2 GHz, while the signal at frequency f _IF may have a relatively low frequency, eg 10 kHz.

The reference frequency f _REF is sent to the prescaler 3324, which divides the frequency by an integer. For example, a frequency of 10 MHz may be divided by 40 to obtain an output frequency of 250 kHz. In this example, the 10 kHz signal entering ADC 3322 is sampled at a rate of 20 kHz, which produces 25 samples per cycle. The signal from ADC 3322 is sent to data processor 3400, eg, one or more digital signal processors.

  The method for extracting the distance is based on the calculation of the phase of the ADC signal for the reference and measurement channels. This method is described in detail in Bridges et al., US Pat. No. 6,057,096, the contents of which are incorporated herein by reference. The calculation includes the use of equations (1) to (8) of Patent Document 2. In addition to this, when the ADM first starts measuring the target, the frequency generated by the synthesizer is changed several times (eg 3 times) and the possible ADM distance is calculated each time. By comparing the possible ADM distances for each of the selected frequencies, the ambiguity of the ADM measurement is eliminated. By combining equations (1) to (8) of Patent Document 2 with the synchronization method and Kalman filter method described in Patent Document 2, the ADM can measure the moving target. In other embodiments, other methods may be used to obtain absolute distance measurements, such as a pulsed time-of-flight method.

  One embodiment of the fiber network 136 of FIG. 4 is shown as fiber network 420A in FIG. This embodiment includes a first optical fiber coupler 430, a second optical fiber coupler 436, and low transmittance reflectors 435, 440. The first and second optical fiber couplers are 2 × 2 couplers, each having two input ports and two output ports. This type of coupler is usually made by placing two fiber cores in close proximity and then drawing the fiber. In this way, evanescent coupling between the fibers can separate the desired portion of light into adjacent fibers. The light travels through the first optical fiber coupler 430 and passes through two paths, that is, the first path through the optical fiber 433 to the second optical fiber coupler 436, the optical fiber 422, and the fiber length equalizing means 423. Divided into a second route through. The fiber length equalization means 423 leads to the optical fiber 138 of FIG. 4, which leads to the reference channel of the ADM electronic component 140. The purpose of the fiber length equalization means 423 is to match the length of the optical fiber that the light passes in the reference channel with the length of the optical fiber that the light traverses in the measurement channel. Matching fiber lengths in this way reduces ADM errors due to ambient temperature changes. Such an error may occur because the effective optical path length of the optical fiber is equal to the average refractive index of the optical fiber multiplied by the length of the fiber. Since the refractive index of the optical fiber depends on the temperature of the fiber, the effective optical path length of the measurement and reference channels is changed by changing the temperature of the optical fiber. When the effective optical path length of the optical fiber in the measurement channel changes with respect to the effective optical path length of the optical fiber in the reference channel, the position of the target 58 appears to change even if the target 58 remains stationary. To avoid this problem, two steps are taken. First, the fiber length in the reference channel is matched as closely as possible to the fiber length in the measurement channel. Second, the measurement and reference fibers are placed as side by side as possible so that the optical fibers in the two channels are exposed to approximately the same temperature changes.

  The light travels through the optical fiber 433 to the second optical fiber coupler 436 and has two paths: a first path to the low reflection fiber terminator 440 and a second optical fiber 438 that exits the fiber network. Divide into routes.

Another embodiment of a fiber network 136 is shown in FIG. In this embodiment, the fiber network 136 includes a first optical fiber coupler 457, a second optical fiber coupler 463, two low reflection terminators 462, 467, an optical switch 468, a retroreflector 472, and an optical switch 468. Electrical input 469. There are several types of optical switches 468. A commercially available and relatively inexpensive type is the MEMS (micro-electro-mechanical system) type. This type may use, for example, a small mirror configured as part of a semiconductor structure. Alternatively, the switch can be a modulator, which can be used for very fast switching at a specific wavelength and is slightly more expensive than a MEMS switch. The switch may also consist of an optical attenuator, which may be responsive to an electrical signal and may be turned on and off by an electrical signal transmitted to the attenuator. A description of the specifications that may be considered in selecting an optical fiber switch is described in Bridges Patent Document 3, the contents of which are incorporated by reference. In general, the switch may be a fiber optic switch to achieve the desired performance and simplicity. It should be understood that the optical switch concept described above should perform equally well in a fiber network based on two colors.

  The fiber network 136 includes an optical switch 468 and a retroreflector 472. Normally, light exits from the fiber 465 through the upper port of the optical switch 468 to the optical fiber 470. However, sometimes, when the laser tracker is not measuring the target, the optical switch 468 branches the optical signal from the optical fiber 465 to the optical fiber 471 and then to the retroreflector 472. The purpose of switching light to the retroreflector 472 is to remove any thermal drift that may have occurred in the components of the ADM system. Such components include, for example, optoelectronic components such as photodetectors, optical fibers of ADM systems, conditioning electronics such as mixers, amplifiers, synthesizers, analog-to-digital converters, and optical components such as lenses and lens mounts. You may go out. For example, suppose initially that the path length of the measurement channel was found to be 20 mm longer than the reference channel with the optical switch 468 that splits the light into the retroreflector 472. Then, suppose that the path length of the measurement channel is found to be 20.003 mm longer than the reference channel path length with the optical switch 468 that branches the light to the retroreflector 472. The ADM data processor will subtract 0.003 mm from subsequent ADM readings. It should be understood that this procedure will be updated each time the tracker sets the ADM value to the laser tracker home position.

  In some embodiments, retroreflector 472 is the fiber optic retroreflector 472A of FIG. Such a retroreflector 472 is generally a ferrule, and the optical fiber is polished at the end of the ferrule and coated with a coating 473, which may be, for example, gold or a multi-layer dielectric film. In other embodiments, the retroreflector 472 is the free space retroreflector 472B of FIG. 9, which includes a collimator 474 and a retroreflector 476, which may be, for example, a cube corner retroreflector slug.

  Another embodiment of a fiber network 136 is shown in FIG. In this embodiment, the fiber network 136 includes a first optical fiber coupler 1730, a second optical fiber coupler 1740, a third fiber coupler 1750, and three low reflection terminators 1738, 1748, 1758. Light from the optical fiber 1781 enters the fiber network 136 at the input port. Light travels through first optical fiber coupler 1730. Part of the light passes through the optical fiber 138 and the fiber length correction means 423 before entering the reference channel of the ADM electronic component 140. Part of the light passes through second optical fiber coupler 1740 and third fiber coupler 1750 and then rides on optical fiber 1753 and exits the fiber network. Light from optical fiber 1743 enters a third fiber coupler 1750 where it is combined with light from a second light source (not shown) through optical fiber 1790 to form a composite light beam, which Proceed over optical fiber 1753. The optical coupler 1750 is a dichroic coupler because it is designed to use two wavelengths. After the composite light beam carried in the optical fiber 1753 exits the laser tracker and is reflected by the target 58, it returns to the fiber network 136. The light from the first light source passes through the third fiber coupler 1750 and the second optical fiber coupler 1740 and enters the optical fiber 148, which reaches the measurement channel of the ADM electronic component 140. Light from the second light source (not shown) returns to the optical fiber 1790 and returns to the second light source (not shown).

  Couplers 1730, 1740, and 1750 may be melted. With this type of optical coupler, the two fiber core / cladding regions are brought close together and melted. As a result, light between the cores is exchanged by evanescent coupling. In the case of two different wavelengths, it is possible to design an evanescent coupling device that can completely transmit the first wavelength along the original fiber and fully couple the second wavelength on the same fiber. . Normally, light is not completely (100%) coupled to coupler 1750. However, fiber optic couplers that provide good coupling for two or more different wavelengths are commercially available at common wavelengths such as 980 nm, 1300 nm, and 1550 nm. In addition, commercially available optical fiber couplers can be purchased for other wavelengths, such as visible wavelengths, and may be designed and manufactured for other wavelengths. For example, in FIG. 10, the optical fiber coupler 1750 can be configured such that the first light of the first wavelength travels from the optical fiber 1743 to the optical fiber 1753, and the optical loss is reduced. At the same time, the apparatus may be configured to couple the second light on the optical fiber 1790 substantially completely on the optical fiber 1753. Therefore, it is possible to transmit the first light and the second light to the same fiber 1753 through the optical fiber coupler with little loss. Optical couplers that combine wavelengths that vary greatly in wavelength are also commercially available. For example, a coupler that couples light having a wavelength of 1310 nm to light having a wavelength of 550 nm is commercially available. Two wavelengths may be relatively close to each other due to long-range propagation that propagates both wavelengths in a single transverse mode, while relatively little loss of optical power during propagation in the optical fiber. Generally desirable. For example, the two selected wavelengths are 633 nm and 780 nm, which are relatively close to each other in wavelength values, and can be transmitted over a long distance, without high loss, through a single mode optical fiber. The advantage of the dichroic fiber coupler 1750 in the fiber network 136 is that it is more compact than a free space beam splitter. In addition, the dichroic fiber coupler aligns the first light and the second light very well, eliminating the need for special optical alignment procedures during production.

  Returning to FIG. 4, the scanner portion 36 may be embedded in a scanner, for example, as shown in FIG. Light from scanner portion 36, such as about 1550 nm infrared light, travels along optical path 150 to dichroic beam splitter 142. The dichroic beam splitter 142 is configured to reflect light from the scanner while allowing light from the laser tracker to pass. Light from the scanner portion 36 travels to the target 58 and returns along the optical path 152 to the annular aperture 154. The return light passes through the annular aperture 154, is reflected by the dichroic beam splitter 142 along the outer optical path, and returns to the scanner portion 36 along the optical path 156. In one embodiment, the outer optical path (defined by the annular opening 154) is coaxial with the inner optical path (defined by the opening 146). By returning the scanner light through the annular aperture 154, the benefit of avoiding unwanted light from the aperture 146 that could damage the light reflected from the target 58 may be obtained.

  In this exemplary embodiment, opening 146 and annular opening 154 are arranged concentrically. In this embodiment, the aperture 146 has an aperture of about 15 mm, the annular aperture 154 has an inner diameter of 15 mm, and an outer diameter of 3 mm.

  It should be understood that in this exemplary embodiment, dichroic beam splitter 142 is positioned at gimbal point 50. In this way, light from both the scanner portion 36 and the tracker portion 34 may appear to be emitted from the same point in the device 30. In this exemplary embodiment, tracker portion 34 emits visible laser light and scanner portion 36 emits light in the near infrared spectrum. The wavelength of light from the tracker portion 34 may be about 70 nm, and the wavelength of light from the scanner portion 36 may be about 1550 nm.

  One embodiment of the scanner portion 36 is shown in FIG. In this embodiment, the scanner portion 36 includes a light emitter 160 that emits a light beam 162 through a collimator 165. The light emitter 160 may be a laser diode that emits light having a wavelength in the range of about 1550 nm. It should be understood that other electromagnetic waves having, for example, smaller or larger wavelengths may be used. The light beam 162 may be intensity or amplitude modulated, for example by a sine or square waveform modulation signal. The light beam 162 is sent to a dichroic beam splitter 172 that reflects the light beam 162 and directs it through the aperture 146 to the target 58. In this exemplary embodiment, light beam 162 is reflected by mirror 170 and dichroic beam splitter 172 so that light beam 162 can travel along the desired optical path of light beams 52, 150. As described in more detail below, using a dichroic beam splitter 172 provides the advantage of allowing the incorporation of a color camera 168 that captures images during operation. In other embodiments, the light emitter 160 is arranged to transmit light directly to the dichroic beam splitter 142 and may not first be reflected by the mirror 170 and dichroic beam splitter 172.

  As shown in FIGS. 4 and 11, the light emitted from the tracker portion 34 and the scanner portion 36 both pass through the same opening 146. The light from these tracker portion 34 and scanner portion 36 is substantially linear and travels along the optical path of the light beam 52 of FIG. On the return path, the light from the tracker portion 34 is reflected by the retro-reflector target so that it is substantially straight when returning to the instrument 30. The return beam of tracker light returns through aperture 146, which is the same aperture as it exits instrument 30. In contrast, light from the scanner portion 36 typically strikes a diffusely scattering object surface 58 'and spreads over a wide angle as it returns. A small portion of the reflected light passes through an annular opening 154 positioned so that the inner diameter is the same (or concentric with) the outer diameter of the opening 146. The return light 163 is reflected by the dichroic beam splitter 172, passes through the lens 160 as the light beam 163, is reflected by the reflecting surfaces 180, 178, 176, passes through the lens group in the light receiver 182, and then the photodetector. To reach. The return scanner light is directed through the annular opening 154 and does not include any light returning through the inner opening 146. This is advantageous because the optical power of the emitted light is much greater than that of the light returned by the object surface 58 ′, and it is desirable to avoid reflections at the optical element back along the path of the inner opening 146. It is.

  In some embodiments, the optional color camera 168 enters the color camera 168 through a portion of the light reflected by the object surface 58 ′ through the dichroic beam splitter 172. The coating on the dichroic beam splitter 172 is selected to pass visible wavelengths picked up by the color camera, while reflecting light of the wavelength emitted by the light emitter 160. The color camera 168 may be coupled to the light receiving lens 160, for example, with an adhesive or in a recess. A color image can be acquired by the color camera 168, which is typically done by taking several individual steps at some point after acquiring the data points by a distance meter in the scanner.

  In some embodiments, the mask 174 is coaxially disposed on the optical axis behind the light receiving lens 160. The mask 174 has a large area through which the return light beam 163 can pass without interruption. The mask 174 has a shielding area positioned radially outward from the optical axis, thereby making the intensity of the return light beam 163 more equal, even if the intensity of the return light is different from the instrument 30 to the object surface 58 '. To be reduced.

  In some embodiments, a rear mirror 176 is placed on the optical axis behind the mask 174. The rear mirror 176 reflects the return light beam 163, which is refracted by the light receiving lens 166 and travels toward the central mirror 178. The central mirror 178 is disposed on the optical axis at the center of the mask 174. In embodiments having a color camera 168, this area may be shaded by the color camera 168. The central mirror 178 may be an aspherical mirror that shifts the focus of the return light beam 163 reflected by the near-field correction lens (ie, the target), even as a negative lens (ie, extending the focal length). ). In addition, reflection is provided only in the extent that the return light beam 163 passes through the mask 174 located on the central mirror 178. The central mirror 178 reflects the return light beam and passes it through the central opening 180 of the rear mirror 176.

  A light receiver 182 having an entrance stop, a collimator with a filter, a condenser lens, and a photodetector is disposed in the vicinity of the rear mirror 176 and opposite to the mask 174. In one embodiment, mirror 184 deflects return light beam 163 by 90 °.

  In one embodiment, the scanner portion 36 may have one or more processors 186, which may be the same as or complementary to the scanner electronics 96 of FIG. The processor 186 performs control and evaluation functions for the scanner portion 36. The processor 186 is coupled to and communicates with the light emitter 160 and the light receiver 182. The processor 186 determines the distance between the instrument 30 and the target 58 for each measurement point based on the time of flight of the emitted beam 162 and the return light beam 163. In other embodiments, the processor 186 and its functions may be incorporated into the controller 64, which may correspond to the scanner electronics 96, master processor 78, external computer 74, or network element 76 of FIG. .

  The optical rangefinders of the tracker portion 34 and the scanner portion 36 may determine the distance using the principle of time of flight. It should be understood that the term time-of-flight is used herein to indicate any method of evaluating the modulated light to determine the distance to the target. For example, the optical power of the light from the tracker portion 34 or the scanner portion 36 may be modulated using a sine wave (intensity modulation). The detected light is evaluated to determine the phase shift between the reference beam and the measurement beam and to determine the distance to the target. In other embodiments, the optical power of the light may be modulated by a substantially square pulsed light. In this case, the leading edge of the pulse may be measured while leaving the device 30 and when returning to the device 30. In this case, the distance to the target is specified using the elapsed time. Another method involves changing the deflection state of the light with respect to time by modulation of an external modulator and then recording the modulation frequency at which the return light disappears after passing through the polarizer. Many other methods for measuring distance are included in the general time-of-flight classification.

  Another common method for measuring distance is called a coherent or interferometric method. Unlike the above-described method in which the optical power of the light beam is evaluated, the coherent or interferometric scheme combines two light beams that are coherent with each other so that optical interference of the electric field occurs. Applying an electric field instead of optical power is the same as applying a voltage instead of electric power. One type of coherent rangefinder changes the wavelength of light with respect to time. For example, the wavelength may be changed in a sawtooth pattern (changing linearly while repeating periodically). Equipment made in this way is sometimes referred to as frequency modulated coherent laser (FMCL) radar. Either the coherent type or the time-of-flight type can be used for the distance meter of the tracker part 34 and the scanner part 36.

  Referring now to FIGS. 12-14, an embodiment of the instrument is shown with the front cover removed and some optical and conditioning electronics omitted for clarity. In this embodiment, the instrument 30 includes a gimbal assembly 3610 that includes a zenith shaft 3630 and an optic bench assembly 3620 having a coupling tube 3622. The Zenith shaft includes a shaft 3634 and a coupling sleeve 3632. Zenith shaft 3630 may be manufactured from a single piece of metal, thereby improving stiffness and temperature stability. FIG. 14 illustrates an embodiment of an optic bench assembly 3720 and a Zenith shaft 3630. Optics bench assembly 3720 includes a primary optics assembly 3650 and a secondary optics assembly 3740. The housing of the main optic assembly 3650 may be manufactured from a single piece of metal, thereby improving rigidity and temperature stability, and includes a coupling tube 3622. In some embodiments, the central axis of the coupling tube 3622 is coincident with the central axis of the coupling sleeve 3632. In one embodiment, four fasteners 3664 attach secondary optic assembly 3740 to main optic assembly 3650. The coupling tube 3622 is inserted into the coupling sleeve 3632 and held in place by three screws 3661. In some embodiments, the coupling tube 3622 is aligned with the coupling sleeve 3632 and two pins at one end of the coupling tube 3622, and the pins fit into the holes 3666.

  The gimbal assembly 3610 is designed to hold an optical component bench assembly 3620, but other types of equipment such as cameras, laser engravers, video trackers, laser pointers, angle measuring instruments, and the like, Light A Detection and Ranging (LIDAR) system can also be installed on the Zenith shaft 3630. The alignment registration provided by the coupling sleeve 3632 allows such equipment to be easily and accurately attached to the gimbal assembly 3610. In this exemplary embodiment, the tracker portion 34 is positioned in the main optic assembly 3650 and the scanner portion 36 is placed in the secondary optic assembly 3740. Dichroic beam splitter 142 is disposed in main optics assembly 3650 as shown in FIG.

  During operation, device 30 has two modes of operation as shown in FIGS. 15 and 16 depending on the desired level of accuracy. The first mode (FIG. 15) uses the tracker portion 34 with a collaborative target 58, such as a retro-reflector target, which may be, for example, a spherically mounted retroreflector (SMR). In this first mode, the instrument 30 emits a light beam 52 that effectively passes through the gimbal point 50, the dichroic beam splitter 142, and the aperture 146 toward the target 58. Light 52 strikes target 58 and some of the light returns along the same optical axis through aperture 146 and dichroic beam splitter 142 back to tracker portion 34. The instrument 30 then determines the distance from the instrument 30 to the target 58 as described above with respect to FIGS. In certain embodiments, during this first mode of operation, the scanner portion 36 does not operate.

  In the second mode of operation shown in FIG. 16, the scanner portion 36 emits a light beam 162 that is reflected by the dichroic beam splitter 142 and emitted toward the target 58 through the aperture 146. It should be understood that the scanner portion 36 may measure the distance to a non-cooperative target and does not require a target such as a retroreflector to obtain a measurement. The light is reflected (scattered) by the target 58 and a portion of the light 163 passes back through the annular opening 154. As mentioned above, it is desirable for the return light 163 to pass through the annular aperture 154 because this provides the advantage of reducing back reflections from optical components that can corrupt the return light signal. . The return light 163 is reflected by the dichroic beam splitter 142 and returns to the scanner portion 36 where the distance from the instrument 30 to the target 58 is determined as described above with respect to FIG. The scanner portion 36 operates continuously while the payload structure 46 is rotated about the azimuth axis 44 and the zenith axis 48 simultaneously. In this exemplary embodiment, the path followed by light beam 162 travels in a single direction (eg, does not reverse) while payload structure 46 rotates about axes 44, 48. This path may be realized by continuously rotating each of the Zenith and azimuth motors in a single direction. In other words, in the second mode, the beam is directed to the object surface 58 ', while the zenith and azimuth angles change continuously and monotonically. Note that the beam may be guided at high speed around one axis (the zenith or azimuth axis) and at the same time may be guided at a relatively low speed around the other axis. In one embodiment, movement of the payload structure 46 causes the light beam to follow a helical path.

  It should be understood that operating the scanner portion 36 such that the path of the light beam 162 need not be reversed provides several advantages over a scanner that follows a raster or random pattern. First, since no reversal of direction is required, a large amount of data can be collected efficiently. As a result, the scanner portion 36 can effectively scan a large area and acquire data at a high sampling rate, such as a three-dimensional point exceeding 1 million per second. Second, by continuously proceeding in a single direction, when the light beam intersects a person, the total energy hitting a certain area of the person can be reduced. As a result, more desirable laser classification based on IEC 60825-1 can be realized.

  In one embodiment, the tracker portion 34 emits a light beam 52 in the visible light spectrum. In this embodiment, tracker portion 34 may emit light beam 52 while scanner portion 36 emits light 162. This is advantageous because the visible light 52 from the tracker portion 34 is a visible reference for the operator.

  Here, with reference to FIGS. 17 to 18, an operation method of the device 30 is shown. Method 190 begins by selecting an operating mode of tracker portion 34 at block 192. The method then proceeds to block 194 where the tracker portion 34 is activated. At block 196, the gimbal mechanism is then moved around the zenith and azimuth axes to direct the light beam toward the target 58. At block 198, the light is reflected from the cooperative target 58 and returns to the instrument 30 through the opening 146. At block 200, the device 30 then calculates the distance from the device 30 to the target 58. At block 202, azimuth and zenith angles are identified and the three-dimensional coordinates (distance and two angles) of the measurement point are identified. This process can be repeated until all desired measurement points have been identified.

  Referring now to FIG. 18, a method 203 is shown in which the scanner portion 36 is selected at block 204. The method 203 then proceeds to block 206 where the scanner portion 36 is activated. If it is desired to provide visible reference light, block 208 activates light from tracker portion 34. Light is transmitted from the scanner portion 36 through the aperture 146 to the target 58. In this exemplary embodiment, as shown in block 209, light from the scanner portion 36 is emitted in one direction (eg, spirally) along the path and the direction is not reversed. The light is reflected by the target 58 and returns to the device 30. At block 210, return light is received through the annular opening 154. At block 212, the distance from the device 30 to the target 58 is identified. At block 214, the azimuth and zenith angles are identified and the coordinates (distance and two angles) to the measurement point on the target 58 are identified.

  The method of directing the light beam from the scanner portion 36 toward the object surface 58 'may be performed otherwise. In the first embodiment, light from the scanner portion 36 is directed at a gimbal assembly 3610 facing in the same direction. In this mode of operation, the beam is directed to any desired point. In a second embodiment, light from the scanner portion 36 is directed at a gimbal assembly 3610 that pivots at a relatively fast constant speed about an axis that can be either an azimuth axis or a zenith axis. The other axis is also moved, but the speed is relatively slow. In this way, the beam is directed in a slow spiral. In the second embodiment, a full scan of a large volume can be performed quickly. Another advantage of the second embodiment is that the time during which the constantly moving beam intersects the pupil of the person's eyes during its continuous movement is shorter. Thus, the desired IEC 60825-1 classification can be provided while using more powerful laser power.

  Referring now to FIG. 19, another embodiment of the instrument 30 is shown, which includes a first absolute rangefinder in the tracker portion 34 and a second absolute rangefinder in the scanner portion 36. The tracker portion 34 and the scanner portion 36 are coupled to a payload structure 46. In this embodiment, the tracker portion 34 and the scanner portion 36 do not emit light on a common optical path. The tracker portion 34 is arranged to direct the light beam 52 in a first radial direction, while the scanner portion 36 is arranged to direct the light beam 162 in a second radial direction toward the object surface 58 '. Is done. The first radial direction and the second radial direction form an angle θ between them. In this exemplary embodiment, the angle θ is 90 °. In other embodiments, the angle θ is between 5 degrees and 180 degrees. However, any suitable angle can be used as long as the tracker portion 34 and the scanner portion 36 can be positioned within the payload structure 46. It should be understood that when the payload structure 46 is rotated about the azimuth axis 44, the tracker portion 34 and the scanner portion 36 are oriented at the same azimuth angle.

  Referring now to FIG. 20, another embodiment of the instrument 30 is shown, which has a tracker portion 34 and a scanner portion 36. In this embodiment, tracker portion 34 is oriented parallel to scanner portion 36 and uses mirror 216 to reflect light 52 toward dichroic beam splitter 142. In this embodiment, dichroic beam splitter 142 is configured to transmit light 162 from scanner portion 36 while reflecting light 52.

The light beams 52, 162 are directed through an aperture 146 and toward an oblique rotating mirror 218 arranged to rotate about the horizontal axis 48 along the optical axis A. Light 52,162 outward is reflected by the center C ₁₀ of the mirror, where it so toward the target 58 is reflected (in the case of tracker portion 34) or the object surface 58 '(when the scanner portion 36) To be biased. Center C ₁₀ defines the origin of the reference system. The light reflected by the target 58 or the object surface 58 ′ is reflected from the rotating mirror 218 and returned toward the opening 146. The light 52 is reflected at the center C ₁₀ of the rotating mirror 218 and returned through the opening 146. The light 52 is reflected by the dichroic beam splitter 142 and the mirror 216 and then returns to the tracker portion 34. The return light 163 is reflected by the rotating mirror 218, passes through the annular opening 154, and returns to the scanner portion 36.

  The directions of the emitted light 52 and 162 and the reflected light are determined from the angular position of the rotating mirror 218 around the horizontal axis 48 and the vertical axis 44. The angular position is measured by encoders 54 and 56, respectively. It should be understood that in one mode of operation, measurements by tracker portion 34 and scanner portion 36 are performed by high speed rotation of rotating mirror 218 and low speed rotation of payload structure 46. Therefore, the entire space is measured step by step while the instrument advances in a circle.

  In some embodiments, the light beam from the scanner is adjustably focused without being collimated. In geometric optics, the focused light beam is a point, but in reality the light beam is a beam waist near the calculated focal position. At the beam waist position, the beam width is minimized as the beam propagates.

  One advantage of sending a focused light beam from the scanner is that a smaller beam can more accurately determine 3D coordinates at the edges. For example, a smaller focused beam can more accurately identify the hole diameter or feature size. Another advantage of sending a focused light beam from the scanner is that the focused beam simply finds the maximum reflection position of the light from the tooling ball retroreflector, which is a shining / highly reflective metal sphere. It is a point that can be guided. By such a method of directing the light beam from the scanner to the tooling ball, the distance and angle to the tooling ball can be accurately measured. For this reason, a tooling ball can be used as a target. A device that integrates the functions of the scanner and tracker will allow two types of targets, SMR and tooling ball, to be used, as described herein. The use of two types of targets allows tracker portion 34 and scanner portion 36 to be easily placed in the same reference frame, which keeps both SMR and tooling balls in the same magnetic nest distributed throughout the environment. Because it can.

  In certain embodiments, an adjustable focus adjustment mechanism 39 is added to other elements of the scanner portion 36. Such an additional adjustable focus adjustment mechanism is shown in FIGS. FIG. 21 is similar to FIG. 4 except that the scanner portion 36 is shown as having two internal elements: a scanner element 37 and an adjustable focus adjustment mechanism 39. FIG. 22 is similar to FIG. 11 except that an adjustable focus adjustment mechanism 39 is included in the scanner portion 36. FIGS. 23 and 24 are similar to FIGS. 15 and 16 except that the scanner portion 36 is shown as having a scanner element 37 and an adjustable focus adjustment mechanism 39. FIG. 25 is similar to FIG. 19 except that the scanner portion 36 is shown to include a scanner element 37 and an adjustable focus adjustment mechanism 39.

  In certain embodiments, the adjustable focus adjustment mechanism 39 includes a number of basic lens elements, as shown in FIG. 26, which may include optional elements 2604, 2606. In addition, the adjustable focus adjustment mechanism 39 includes a lens element 2602 that is attached to a motorized adjustable stage 2610 configured to move the lens 2602 back and forth so that it can be adjusted as desired. In some embodiments, the scanner electronics 96 of FIG. 3 electrically controls the motorized adjustable stage 2610.

  Various lens assemblies and adjustment methods are known in the art to provide an adjustable focus in the lens assembly. Those skilled in the art will appreciate that any of the methods may be used to provide the adjustable focus within the present invention.

  Although the invention has been described in detail in connection with only a limited number of embodiments, it should be readily understood that the invention is not limited to such disclosed embodiments. Rather, the invention may be modified to incorporate any number of variations, alternatives, substitutions, or equivalent arrangements not heretofore described, but equal to the spirit and scope of the invention. In addition, while various embodiments of the invention have been described, it is understood that aspects of the invention may include only some of the described embodiments. Accordingly, the invention is not to be seen as limited by the foregoing description, but is only limited by the scope of the appended claims. Furthermore, the use of the terms first, second, etc. does not imply any order or significance, and the terms first, second, etc. are intended to distinguish one element from another. Is used. Further, the use of terms such as article (a, an) does not imply a limit on quantity, but means that there is at least one item mentioned.

  30 Coordinate Measuring Equipment, 32 Housing, 34 Tracker Part, 36 Scanner Part, 37 Scanner Element, 38 Gimbal Beam Steering Mechanism, 39 Adjustable Focus Adjustment Mechanism, 40 Azimuth Base, 42 Zenith Carriage, 44 Azimuth Shaft, 46 Payload Structure , 48 Zenith axis, 50 Gimbal point, 51 Zenith motor, 52, 162, 163 Light beam, 54 Zenith angle encoder, 55 Azimuth motor, 56 Azimuth angle encoder, 58 Target (retro reflector target), 58 'Object surface, 60 Magnetic nest , 64 Controller, 66 Distributed processing system, 68 Temperature sensor, 72 Personal digital assistant, 74 External computer, 76 Network component, 78 Master processor, 80 Payload functional electronics Product unit, 82 azimuth encoder electronic component, 86 Zenith encoder electronic component, 88 display and UI electronic component, 90 removable storage hardware, 92 wireless electronic component, 94 antenna, 96 scanner electronic component, 98 camera electronic component, 100, 102, 104 electronic components, 106, 108, 110 bus lines, 112, 114, 116, 118 buses, 120, 122, 124 communication links, 126 light sources, 128 isolators, 130 fiber injection systems, 132 beam splitters, 134 position detectors, 136 Fiber network, 138, 148, 422, 433, 438, 465, 470, 471, 1743, 1753, 1781, 1790 Optical fiber, 140 Electronic components, 142, 172 da Croix beam splitter, 144, 150, 152, 156 optical path, 146 inner aperture, 154 annular aperture, 160 light emitter, 165 collimator, 166 light receiving lens, 168 color camera, 170, 184, 216 mirror, 174 mask, 176 rear mirror 178 central mirror, 180 reflecting surface, 180 central aperture, 182 light receiver, 186 processor, 218 rotating mirror, 420A fiber network, 423 fiber length equalization means (fiber length correction means), 430, 1740, 1750 optical fiber coupler, 435 low transmittance reflector, 436, 457, 463, 1730 optical fiber coupler, 440 low reflection fiber terminator, 462, 1738 low reflection terminator, 468 optical switch, 469 electrical input, 72,476 retroreflector, 472A fiber optic retroreflector, 472B free space retroreflector, 473 coating, 474 collimator, 2602, 2604, 2606 lens element, 2610 motorized adjustable stage, 3302 frequency reference, 3304 synthesizer, 3306 measurement detection 3308 reference detector 3310 measurement mixer 3312 reference mixer 3314 3316 conditioning electronics 3324 prescaler 3400 data processor 3610 gimbal assembly 3620 3720 optics bench assembly 3622 coupling tube 3630 Zenith shaft 3632 Coupling sleeve 3634 Shaft 3650 Main optics assembly 36 4 fastener, 3666 hole, 3740 secondary optics assembly.

Claims (22)

In coordinate measuring equipment,
An optical transmission system;
A first absolute rangefinder including a first light source, a first photodetector, and a first electrical circuit, wherein the first light source sends the first light to the retroreflector target through an optical transmission system. The first photodetector is further configured to generate a first electrical signal in response to the first light being reflected by the retroreflector target and to convert the first electrical signal to the first electrical circuit. And the first electrical circuit is configured to determine a first distance from the coordinate measuring instrument to the retroreflector target based at least in part on the first electrical signal. The first absolute rangefinder,
A second absolute distance meter including a second light source, an adjustable focus adjustment mechanism, a second photodetector and a second electrical circuit, wherein the second light source is through an adjustable focus adjustment mechanism and an optical transmission system The second light detector is configured to send the second light to the object surface, the second photodetector is configured to receive a portion of the second light reflected by the object surface and passed through the light transmission system; The second photodetector further generates a second electrical signal in response to receiving a portion of the second light reflected by the object surface and passes the second electrical signal to the second electrical circuit. The second electrical circuit is configured to transmit and the second electrical circuit is configured to determine a second distance from the coordinate measuring device to the object surface based at least in part on the second electrical signal. Two absolute distance meters,
A structure operatively coupled to the optical transmission system, the first absolute distance meter, and the second absolute distance meter;
A first motor configured to rotate the structure about a first axis;
A first angle transducer operably coupled to the structure, the first angle transducer configured to measure a first rotation angle about a first axis;
A second motor configured to rotate the structure about a second axis, wherein the second axis is substantially perpendicular to the first axis;
A second angle transducer operably coupled to the structure, wherein the second angle transducer is configured to measure a second rotational angle about the second axis;
A position detector, configured to receive a portion of radiation emitted by a coordinate measuring instrument and reflected by a retroreflector target, and at least partially based on a position where a portion of the radiation strikes the position detector. A position detector configured to generate three electrical signals;
A processor having a computer readable medium configured to operate in a first mode and a second mode;
Including
The first mode tracks the retroreflector target at least in part based on the third electrical signal, and the first three-dimensional coordinates of the retroreflector target at least in part at the retroreflector at the first position. Determining based on a first rotation angle to the target and a second angle of the retroreflector target at the first position and a first distance of the retroreflector target at the first position;
The second mode directs the second light to the object surface, and the second three-dimensional coordinates of a point on the object surface, at least in part, the first rotation angle to that point on the object surface And determining a second rotation angle of the point on the object surface and a second distance of the point on the object surface, and the second mode includes adjusting the adjustable focus adjustment mechanism. Furthermore, the coordinate measuring device characterized by including. In the coordinate measuring instrument according to claim 1,
The optical transmission system has an inner optical path and an outer optical path, the outer optical path is coaxial with the inner optical path and is outside the inner optical path,
The first photodetector is configured to receive the first light reflected by the retroreflector target and passed through the inner optical path of the optical transmission system;
A coordinate measuring instrument, wherein the second photodetector is configured to receive the second light reflected by the object surface and passed through the outer optical path of the light transmission system. In the coordinate measuring instrument according to claim 1,
A coordinate measuring instrument that emits second light along a spiral path by rotating the structure in one direction. In the coordinate measuring instrument according to claim 1,
The coordinate measuring instrument further comprises an annular aperture positioned to receive a portion of the second light reflected by the object surface. In the coordinate measuring instrument according to claim 4,
The coordinate measuring instrument, wherein the processor is configured to emit the first light when the second absolute distance meter emits the second light. In the coordinate measuring instrument according to claim 1,
A coordinate measuring instrument characterized in that the wavelength of the first light is about 700 nanometers. In the coordinate measuring instrument according to claim 6,
A coordinate measuring instrument characterized in that the wavelength of the second light is about 1550 nanometers. In coordinate measuring equipment,
Structure and
A first motor configured to rotate the structure about a first axis;
A first angle transducer operably coupled to the structure, the first angle transducer configured to measure a first rotation angle about a first axis;
A second motor configured to rotate the structure about a second axis, wherein the second axis is substantially perpendicular to the first axis and the projection of the second axis is A second motor that intersects the projection of the first axis at the gimbal point;
A second angle transducer operably coupled to the structure, wherein the second angle transducer is configured to measure a second rotational angle about the second axis;
An optical transmission system operatively coupled to the structure;
A first absolute distance meter operatively coupled to the structure, comprising a first light source, a first photodetector, and a first electrical circuit, wherein the first light source is through a first optical transmission system. Configured to send a first light along a portion of a first line extending from the gimbal point to the retroreflector target, the first line being perpendicular to the first axis and the first photodetector Is configured to receive the first light reflected by the retroreflector target and passed through the optical transmission system, and the first photodetector is further responsive to the first light being reflected by the retroreflector target. Generating a first electrical signal and transmitting the first electrical signal to the first electrical circuit, wherein the first electrical circuit determines a first distance from the coordinate measuring instrument to the retroreflector target, At least partly the first electricity A first absolute distance meter as configured to determine, based on the item,
A second absolute distance meter operatively coupled to the structure, comprising a second light source, an adjustable focus adjustment mechanism, a second photodetector, and a second electrical circuit, wherein the second light source comprises: Configured to send a second light along a portion of a second line extending from the gimbal point to the object surface through an adjustable focus adjustment mechanism and an optical transmission system, the second line being perpendicular to the first axis And the second line is different from the first line, the second photodetector is configured to receive a portion of the second light reflected by the object surface and passed through the light transmission system; The second photodetector further generates a second electrical signal in response to receiving a portion of the second light reflected by the object surface, and converts the second electrical signal to the second electrical circuit. A second electrical circuit configured to transmit a second distance from the coordinate measuring instrument to the object surface, An absolute distance meter second as being configured to determine on the basis of the second electrical signal to a portion of even without,
A position detector, configured to receive a portion of radiation emitted by a coordinate measuring instrument and reflected by a retroreflector target, wherein a third electrical signal is located at least in part with a portion of light radiation. A position detector configured to generate based on a position hitting the detector;
A processor having a computer readable medium configured to operate in a first mode and a second mode;
Including
The first mode includes tracking the retroreflector target based at least in part on the third electrical signal and the first three-dimensional coordinates of the retroreflector target at least in part on the retro at the first position. Determining based on a first rotation angle of the reflector target and a second rotation angle to the retro reflector target at the first position and a first distance of the retro reflector target at the first position;
The second mode involves rotating the structure about a first axis and the second three-dimensional coordinates of the point on the object surface at least partially to the first rotation to that point on the object surface. The second mode adjusts the adjustable focus adjustment mechanism, including determining based on the angle and a second rotation angle to that point on the object surface and a second distance of that point on the object surface The coordinate measuring instrument further comprising a step. The coordinate measuring instrument according to claim 8,
Coordinates characterized in that the first line extends in the first radial direction and the second line extends in the second radial direction, forming an angle between them, the angle being between 5 and 180 degrees measuring equipment. The coordinate measuring instrument according to claim 9,
A coordinate measuring instrument characterized in that the angle is 90 degrees. The coordinate measuring instrument according to claim 8,
A coordinate measuring instrument characterized in that the wavelength of the first light is about 700 nanometers. The coordinate measuring instrument according to claim 9,
A coordinate measuring instrument characterized in that the wavelength of the second light is about 1550 nanometers. The coordinate measuring instrument according to claim 8,
The coordinate measuring instrument further comprises an annular aperture positioned to receive a portion of the second light reflected by the object surface. The coordinate measuring instrument according to claim 8,
The coordinate measuring instrument, wherein the processor is configured to emit the first light when the second absolute distance meter emits the second light. In coordinate measuring equipment,
An optical transmission system;
A first absolute rangefinder including a first light source, a first photodetector, and a first electrical circuit, wherein the first light source sends first light to a retroreflector target through an optical transmission system. And the first photodetector is configured to receive the first light reflected by the retroreflector target and passed through the optical transmission system, and the first photodetector is further configured to receive the first light. A first electrical signal is generated in response to being reflected by the retroreflector target and is configured to transmit the first electrical signal to the first electrical circuit, the first electrical circuit comprising the coordinate measuring instrument A first absolute distance meter configured to determine a first distance from the retroreflector target to at least in part based on the first electrical signal;
A second absolute rangefinder including a second light source, an adjustable focus adjustment mechanism, a second photodetector, and a second electrical circuit, wherein the second light source comprises an adjustable focus adjustment mechanism and an optical transmission system The second light detector is configured to receive a portion of the second light reflected by the object surface and passed through the light transmission system; The second photodetector further generates a second electrical signal in response to receiving a portion of the second light reflected by the object surface, and converts the second electrical signal to the second electrical circuit. The second electrical circuit is configured to determine a second distance from the coordinate measuring instrument to the object surface based at least in part on the second electrical signal. A second absolute distance meter,
A structure operatively coupled to the optical transmission system, the first absolute rangefinder, and the second absolute rangefinder, comprising a mirror mounted for rotation, the mirror comprising the first light and the second absolute rangefinder A structure that is arranged in the optical path of light,
A first motor configured to rotate the structure about a first axis;
A first angle transducer operably coupled to the structure, the first angle transducer configured to measure a first rotation angle about a first axis;
A second motor configured to rotate the mirror about a second axis, wherein the second axis is substantially perpendicular to the first axis;
A second angle transducer operatively connected to the mirror, the second angle transducer configured to measure a second rotation angle about the second axis;
A position detector, configured to receive a portion of radiation emitted by a coordinate measuring instrument and reflected by a retroreflector target, wherein a third electrical signal is located, at least in part, of the radiation. A position detector configured to generate based on a position hitting the device;
A processor having a computer readable medium configured to operate in a first mode and a second mode;
Including
The first mode includes tracking the retroreflector target based at least in part on the third electrical signal and the first three-dimensional coordinates of the retroreflector target at least in part on the retro at the first position. Determining based on a first rotation angle to the reflector target, a second rotation angle to the retro-reflector target at the first position, and a first distance of the retro-reflector target at the first position;
The second mode involves rotating the structure about a first axis and a second three-dimensional coordinate of a point on the object surface, at least partially to the first position to that position on the object surface. The second mode adjusts the adjustable focus adjustment mechanism, including determining based on the rotation angle and a second rotation angle to that position on the object surface and a second distance of that point on the object surface A coordinate measuring device further comprising the step of: The coordinate measuring instrument according to claim 15,
In the second mode, the first motor rotates the structure at a first speed, the second motor rotates the mirror at a second speed, and the second speed is faster than the first speed. Coordinate measuring equipment. The coordinate measuring instrument according to claim 16,
The second mode includes a step of rotating the structure in one direction around the first axis. The coordinate measuring instrument according to claim 17,
A coordinate measuring instrument characterized in that rotation in one direction of the first axis emits second light along a spiral path. The coordinate measuring instrument according to claim 15,
A coordinate measuring instrument characterized in that the wavelength of the first light is about 700 nanometers. The coordinate measuring instrument according to claim 19,
A coordinate measuring instrument characterized in that the wavelength of the second light is about 1550 nanometers. The coordinate measuring instrument according to claim 15,
The coordinate measuring instrument further comprises an annular aperture positioned to receive a portion of the second light reflected by the object surface. The coordinate measuring instrument according to claim 15,
The coordinate measuring instrument, wherein the processor is configured to emit the first light when the second absolute distance meter emits the second light.

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