POSITION FINDER DEVICE AND METHOD USING OPTICALLY PROJECTED REFERENCE

Abstract

Sensor device (1) for a computer-controlled machine (2) with a movable carrier (3) for changing the position of a first machine part (4) relative to that of a second machine part (5), wherein the sensor device (1) comprises: a pattern generator (6) attachable to the first machine part (4), a first coherent light illumination device (7A) and a second coherent light illumination device (7B), both attachable to the second machine part (5) and optically configured to illuminate the pattern generator (6) with coherent light to generate a spatial light pattern (8), a camera (9) attachable to the second machine part (5) and optically configured to capture a composite image (30) of the spatial light pattern (8), wherein the sensor device (1) can be configured tothat it is possible for the camera (9) to capture a first composite image of the spatial light pattern (8) in a first camera shot, using a combination of the camera (9) and the first (7A) coherent light illumination device and the second (7B) coherent light illumination device, wherein a range of effective optical distances of a first optical configuration, in which light is transmitted along optical paths from the first illumination device (7A) via the pattern generator (6) to the camera (9) to generate a first spatial light pattern component (8A) of the spatial light pattern (8), does not overlap with a range of effective optical distances of a second optical configuration, in which light is transmitted along optical paths from the second illumination device (7B) via the pattern generator (6) to the camera (9) to generate a second spatial light pattern component (8B) of the spatial light pattern (8),overlaps, and wherein each of the first (7A) and second (7B) illumination devices is configured to illuminate the pattern generator (6) with coherent light of a coherence length greater than a maximum optical path length difference within each of the first and second optical configurations, and wherein the sensor device (1) in at least one of the first and second optical configurations comprises means to prevent optical cross-interference between the first component (8A) and the second component (8B) in the composite image (30), the means being at least one of the following: a) a laser in the first coherent light illumination device (7A) having a wavelength different from the wavelength of a laser used in the second coherent light illumination device (7B), b) polarizing optics such as polarizers, wave plates,birefringent prisms and polarizing cube beam splitters in the optical paths of the optical configurations to make the polarization state of the light of the first component orthogonal to the polarization state of the light of the second component; c) an optical component arrangement that allows the light of the first optical configuration to enter the light-sensitive surface of the camera (9) at angles sufficiently different from the light of the second optical configuration so that the optical cross-interference between the first component (8A) and the second component (8B) is not resolved by the camera (9); and d) aperture shutters, deflectors, or amplitude modulators in the optical paths of the optical configurations to cause the first illumination device (7A) to produce light.that exposes the light-sensitive surface of the camera (9) at different times within the exposure time period of the composite image compared to the second light illumination device (7B).

Description

BACKGROUND OF THE INVENTION / DESCRIPTION OF THE STATE OF THE ART.

[0001] The present invention relates to the field of devices and methods for finding exact translations and rotations within computer-controlled machines such as machine tools, opto-mechanical measuring devices, coordinate measuring machines (CMMs), robots, and position encoders. In particular, the invention relates to solid-state translation and rotation calibration at a plurality of machine part positions or simultaneous translation and rotation reading within such devices.

[0002] With reference to XYZ -Coordinate axes is, in the following, the translation of a part by a coordinate axes. X -, Y -, Z -coordinate of a specific point on this part is meant. With the rotation of the same part, the Rx -, Ry -, Rz -rotation angle of this part is meant, whereby Rx , Ry and Rz on the rotation angles around the given X , Y or Z -axis. The position of a part, in a broader sense, refers to either the combined translation and rotation, the translation, or the rotation of a part. Typically, the machines mentioned above use translational reading devices, so-called encoders, to read the exact translation of different parts of the machine. For example, if such a machine has three translational degrees of freedom, XYZ , and a rotation angle degree of freedom, θ, are built, linear encoders are located at each of three respective X -, Y - and ZAn angled encoder is placed on a rotational axis of a θ-beam of the machine. However, these encoders are typically located away from the machine's workspace (or work area); otherwise, the encoders would conflict with the machine's workspace operations. Consequently, to determine the translation of a particular machine part or tool within the workspace, translations and rotations of several machine parts must be determined from measurements taken by the respective encoders. By using geometric information and performing geometric calculations based on the measurements, the translation and rotation of the specific machine part, or more commonly, the translation and rotation of a tool located within the machine's workspace, are derived.However, mechanical irregularities, gaps, and / or mechanical play affect machine part movements. Thus, translational and rotational offsets between the encoder read positions and the work area operation positions introduce difficult-to-measure misalignments associated with each degree of freedom, whose misalignments are not considered in the geometric calculations. This, in turn, leads to a degree of uncertainty and error in the determined machine part positions.

[0003] To measure and calibrate the 3D (three-dimensional) positioning of, for example, machine tools, opto-mechanical devices, and encoders, so-called probes are typically used. A probe can be mounted in the tool holder of the machine tool and moved to contact the calibrated position of measuring instruments such as steel balls or rods. This is a time-consuming point-to-point process and requires the mounting and use of expensive dimensionally calibrated measuring instruments.

[0004] Typically, an encoder measures the 1D (one-dimensional) translations along a rod or, to read a rotation angle, the 1D rotation on the circumference of a rotating shaft. Extending these same processes to simultaneously read both translations and rotations for some or all of the 6 (3 translations + 3 rotations) possible mechanical degrees of freedom of a rigid body can be complicated and expensive. Current encoders, also due to accuracy limitations, may not be well-suited to capturing the difference between, for example, the translations along two rods and potentially extrapolating these difference translations into values ​​for translations at locations far beyond the rods.

[0005] In the literature, such as Christopher J. Dainty's (ed.) *Laser Speckle and Related Phenomena*, Springer Verlag, Berlin 1974, a number of so-called speckle photography and speckle interferometry techniques are described. The focus of these techniques is on measuring object-internal deformations and surface topography. Speckle photography techniques are unable to measure both local translational and rotational angular displacements at a multitude of partial positions in 3D space. Consequently, and additionally, interferometric techniques are sensitive to vibrations and, in many cases, not well-suited for industrial applications.

[0006] Later, for example, Ichirou Yamaguchi et al. in Applied Optics, Vol. 28, No. 20, October 15, 1989, and Vijay Shilpiekandula in his master's thesis, Massachusetts Institute of Technology, February 2004, describe how a defocused or focused camera can be used to create a rotation angle reader by recording speckle displacement using, for example, a camera. This technique also lacks the ability to measure both local translational and rotational displacements at a multitude of subpositions in 3D space.

[0007] European patent EP1924400 describes a device and method for finding and identifying part position relationships of components in mechanical and opto-mechanical machining and quality control systems. This technique describes, among other things, correlation techniques for detecting image displacement of a focused surface structure. However, this technique lacks the capability to measure both translational and rotational displacements at a multitude of part positions in 3D space.

[0008] Therefore, known mechanical and optical devices and methods for detecting translations and rotations within computer-controlled machines lack sufficient measuring capability, accuracy, or speed, or they are too sensitive or prone to errors. Furthermore, they generally require time-consuming and / or expensive calibration.

[0009] In patent application PCT / NO2015 / 050102, Gudmund Slettemoen describes how the translational offsets ( dAx , dAy ) and ( dBx , dBy ) between at least two images in at least two configurations A and B can be combined to determine the values ​​of the translation offsets ( Dx , Dy ) and rotation angle offsets ( Tx , Ty ) between two machine parts. This technique is capable of measuring both translational and rotational offsets at a multitude of partial positions in 3D space, but can be sensitive to drift in light source wavelengths or mechanical drift of cameras or other optical components, since the images are acquired separately. TASKS OF INVENTION

[0010] One object of the invention is to improve the accuracy of determining either partial translation or rotation, or both partial translation and rotation, within the workspace of computer-controlled machines. Another object of the invention is to reduce the time required for calibrating computer-controlled machines. A further object of the invention is to provide the computer control of machines with improved speed and accuracy for translation and / or rotation correction data, or to provide solutions that function directly as advanced translation and / or rotation encoders. SUMMARY

[0011] These and other tasks and advantages, which will become apparent from the following description of the present invention, are achieved by the device, the system, and the methods according to the attached independent claims. Further aspects of the invention are defined in the accompanying claims.

[0012] According to one aspect, the invention provides a sensor device suitable for use in a computer-controlled machine with a movable carrier for changing the position of a first machine part relative to a second machine part located in the working space of the computer-controlled machine. The sensor device comprises a first pattern generator attachable to the first machine part, at least one first and one second illumination device attachable to the second machine part and configured to illuminate the first pattern generator in order to produce, together with the light scattered by the first pattern generator, a three-dimensional light diffraction and interference pattern, hereinafter referred to as a spatial light pattern or a spatial pattern of light or simply as a light pattern, in the aforementioned working space, and a camera attachable to the second machine part.The sensor device is configurable such that the camera is able to capture a composite image of the spatial light pattern in the workspace, which is formed from at least two different optical configurations, such that each includes the camera and one of the first and one of the second illumination devices respectively, and wherein the composite image is the image that is captured in one and the same camera exposure of the spatial light pattern, which is composed of spatial light pattern components that are generated in each of the different optical configurations.The different optical configurations differ in that a range of effective optical distances of a first optical configuration, in which light is transmitted along optical paths from a first illumination device via the first pattern generator to the camera to generate a first spatial light pattern component of the spatial light pattern, does not overlap with a range of effective optical distances of a second optical configuration, in which light is transmitted along optical paths from a second illumination device via the first pattern generator to the camera to generate a second spatial light pattern component of the spatial light pattern.Therefore, in a sensor device according to the invention, the effective distance de of an optical configuration, which is the inverse of the harmonic sum of the distance from the illumination divergence center to the pattern generator di, the distance from the camera object plane to the pattern generator dc and the effective focal length f of the pattern generator, differs from the effective distance de of another optical configuration, wherein (1 / de)=(1 / di)+(1 / dc)+(1 / f).

[0013] In one embodiment, the sensor device of the invention advantageously includes a means of preventing cross-interference between light from different spatial light pattern components formed in the various optical configurations in the composite image. Examples of means of preventing such cross-interference include a laser used in a coherent light illumination device with a wavelength different from that of a laser used in another coherent light illumination device; polarizing optics in the optical paths of the various optical configurations, which establish the polarization state of the light of one light pattern component orthogonal to the polarization state of the light of another light pattern component; aperture shutters, deflectors, or amplitude modulators.which are arranged in the optical paths of the optical configurations to cause the light transmitted in the paths of the different optical configurations to expose the photosensitive surface of the camera at different times within an exposure time span of one and the same composite image, and an arrangement of optical components that ensure that the minimum angular separation between the spatial light pattern components, measured from the photosensitive surface of the camera, is greater than an angular separation determined by the pixel size of the camera and the wavelength of the light involved.

[0014] In one embodiment, the sensor device further comprises storage means for receiving the data of the composite images from the at least one camera as well as position data of one carrier, and is configured to record composite images of the spatial light pattern in at least one first and second different optical configuration of the at least first and second illumination device, the camera and the pattern generator.

[0015] According to one aspect of the invention, the at least first and second lighting devices are configured to illuminate the pattern generator with at least partially coherent light. Advantageously, the spatial light pattern extends more widely in space the higher the degree of coherence of the light.

[0016] According to a further aspect, the sensor device of the invention advantageously includes a second pattern generator, which can be attached to the second machine part and which is configured to capture with the camera a composite image of the spatial light pattern formed using the second pattern generator in a third optical configuration in addition to the first pattern generator in the first and second optical configurations. In this case, at least one of the illumination devices is arranged such that it also illuminates the second pattern generator in order to generate a third spatial light pattern component of the spatial light pattern.

[0017] According to a further aspect of the invention, for the purpose of generating reference images, the configuration means of the sensor device can be operated, which enables the camera to take reference images of light patterns that are formed separately in each of the various optical configurations involved.

[0018] A system according to one aspect of the invention comprises a sensor device according to any of the above aspects and a storage means for carrying a reference database. The reference database comprises interconnected reference image and carrier position data, which represent the exact translation and rotation of a reference machine part relative to the pattern generator. The provision of the reference database makes it possible to associate composite images recorded in a first computer-controlled machine with reference images recorded previously or subsequently in a second computer-controlled machine. The second machine is a reference machine in which the same optical configurations are used when recording the reference images as in the first machine.

[0019] From one perspective, the system further includes a processing means configured to process the recorded composite image data with reference image data to find sets of corresponding images, to derive image translation offset data for each set of corresponding images, and to derive positional data for calibrating the computer-controlled machine based on image translation offset data associated with a variety of different optical configurations. The processing typically involves comparing recorded composite image data with reference image data, and the set of corresponding images is usually a pair of corresponding images.The processing tool enables the system to automatically determine the correspondence of composite images with reference images and, based on the determined correspondence, to derive position data for the calibration of the computer-controlled machine.

[0020] Another aspect describes a method for recording data associated with the relative translation and rotation of a first and a second part of a computer-controlled machine. The computer-controlled machine includes movable supports for changing the position of the first machine part relative to the second machine part. The method comprises the steps of moving the supports to a multitude of positions. At each position, lighting devices are used to illuminate a pattern generator attached to the first machine part, thus producing a spatial light pattern. Furthermore, at each position, a composite image of the spatial light pattern, formed in at least two different optical configurations, is recorded using the lighting devices and at least one camera.This method enables the rapid and accurate acquisition of data associated with the translation and rotation of the first machine part relative to the translation and rotation of the second machine part. Consequently, the method allows for the dense scanning of translational and rotational offsets in a computer-controlled machine, such as a machine tool or a coordinate measuring machine. As a result, by recording composite images, the method is less sensitive to drift in light source wavelengths, mechanical drift of computer-controlled machine components, and mechanical drift of optical components and cameras.

[0021] From one perspective, the procedure includes the further procedural step of recording the position of the carriers at each location.

[0022] From one perspective, a multitude of lighting devices are controlled at each position to illuminate the pattern generator simultaneously or alternately.

[0023] According to one aspect, a method for deriving data for calibrating a computer-controlled machine is provided. The computer-controlled machine comprises a movable carrier for changing the position of a first machine part relative to a second machine part. This method comprises the steps of providing a first and second machine part of the computer-controlled machine, each with an element of the sensor device of the invention; of moving the carrier to a multitude of carrier positions, such that the position of the first machine part relative to the second machine part changes for each position; of operating the sensor device of the invention at each carrier position, wherein the lighting devices are operated to illuminate a pattern generator attached to the first machine part, so that the spatial light pattern is generated; to record position data at each support position, relating to the position of the support; that at each carrier position a composite image of the spatial light pattern is captured and recorded at at least two different optical configurations of the at least two lighting devices, the first pattern generator and at least one camera; that for each respective carrier position, pairs of similar light pattern data are found by comparing the recorded composite image data with reference image data from a reference database, wherein the light pattern data includes interlinked light pattern and position data associated with the unique spatial light pattern reflected or transmitted by the pattern generator, including the internal pattern generator; and that similar light pattern data are analyzed to derive light pattern translation offset data for each pair of similar light patterns. Furthermore, data for the calibration or compensation of the computer-controlled machine are derived based on light pattern translation offset data associated with a variety of different optical configurations.

[0024] From one perspective, the pattern generator is illuminated with at least partially coherent light. The coherence of the light makes it possible to produce the spatial light pattern.

[0025] Among the advantages of the invention is the ability to record reference images of light patterns and use these reference images on different machines. Advantageously, it is also possible for one machine to serve as the reference for its subsequent performance. A further advantage of the invention is its applicability to finding and calibrating the translation and rotation of a computer-controlled machine, since the present invention is advantageously arranged to associate differently configured recordings of light patterns with encoder position measurements. List of characters Fig. Figure 1 is a schematic side view drawing illustrating a first embodiment of a milling machine equipped with a system comprising a sensor device according to the present invention. Fig. Figure 2 is a schematic side view drawing illustrating a first embodiment of a coordinate measuring machine equipped with a system comprising a sensor device according to the present invention. This machine collects the reference data used by the milling machine, as described by Fig. 1 shown. Fig. Figure 3 is a schematic drawing of the side view, showing optical paths and effective distances of the milling machine. Fig. 1 and the coordinate measuring machine from Fig. 2 represents. Fig. Figure 4 is a schematic drawing of the side view of the milling machine from Example 1, but equipped with an alternative system comprising a sensor device according to the present invention. The use of this sensor device enables all 6 degrees of freedom ( 3 Translations + 3 rotations) of a rigid body movement at a multitude of positions for the milling machine in relation to a coordinate measuring machine with a similarly configured sensor device. Fig. 5 is a schematic drawing of the side view, showing optical paths and effective distances of the components in the milling machine. Fig. 4 represents the sensor device shown and is used in a corresponding reference image recording machine. Fig. Figure 6 is a schematic drawing of the projection view of a vertical milling machine equipped with a sensor device according to the present invention, wherein the sensor device is equipped with additional reference configurations suitable for compensating the drift of the light source wavelength or the positional drift of mechanical and optical components or the mechanical or thermal drift of the camera. Fig. 7 is a schematic drawing of the side view, showing the optical paths and effective distances of the sensor device, which is mounted in the vertical milling machine. Fig. Figure 6 is shown and is used in a corresponding reference image recording machine. ADVANTAGES.

[0026] The method of this invention enables fast and accurate sampling of data associated with the translation and rotation of the first machine part relative to the translation and rotation of the second machine part. Consequently, the method enables dense sampling of translational and rotational offsets in a computer-controlled machine, such as a machine tool or a coordinate measuring machine, relative to those of a reference machine. This is achieved by comparing a composite image of a spatial light pattern formed by at least two optical configurations with the images in a reference database, wherein the images in the reference database are images of spatial reference light patterns formed separately by the different configurations.The comparison, which relies on linked spatial light patterns and positional data associated with the spatial optical characteristics of a pattern generator, makes it possible to compare the position of a spatial light pattern captured and recorded in a first computer-controlled machine with spatial reference light patterns recorded before or after in a computer-controlled reference machine, such as a coordinate measuring machine or a calibration setup, using the same optical configurations. This allows for the precise determination of translational and rotational offsets at each sample position and the use of the offset data to derive data for positional calibration or compensation of the first computer-controlled machine.The calibration data can be used to read or control the movement of the first computer-controlled machine, so that its movement is corrected by the movement of the reference machine used to record the reference data. By simplifying image acquisition, the present invention also extends the scope of the applications that can be derived from patent application PCT / NO2015 / 050102.

[0027] By associating exact positions and angles of optical configurations of cameras and lighting devices with the position and angle of a physical part, hereafter referred to as the pattern generator, the present invention makes it possible to find the exact toolholder translation and rotation in a computer-controlled machine by transferring the pattern generator or an exact sister copy of the pattern generator from one machine (reference) to another, and by observing the light patterns created with sensor devices which are defined by the same optical configurations.By capturing composite images, the present invention is able to simultaneously improve both speed and accuracy, since each composite image contains all the necessary position and rotation information about the computer-controlled machine at the time the image is captured. This results in a high degree of reliability and accuracy.

[0028] The pattern generator essentially serves the same purpose as, for example, the encoder glass rod of a commercially available encoder. By capturing composite images, the present invention enables the recording of translations and rotations of a spatial light pattern in free space outside the pattern generator and uses this information to determine the exact translational and rotational offset conditions of machine parts.

[0029] The sensor device enables fast and accurate image acquisition associated with the translation and rotation of the first machine part relative to the translation and rotation of the second machine part. Consequently, the device allows for dense scanning of translational and rotational offsets in a computer-controlled machine, such as a machine tool or a coordinate measuring machine. The provision of at least two different optical configurations makes it possible to derive reliable information on the translation of the first part relative to the translation of the second part, separately from the rotation of the first part relative to the rotation of the second part.Since the effective distance of the first optical configuration differs from that of the second, it is also possible to record a composite image of the spatial light pattern that contains sufficient translational and rotational information at each sample position. This allows for the rapid determination of translational and rotational offsets at each sample position and the use of this offset data to compensate for positioning in the first computer-controlled machine. This ensures that the positioning in the first machine closely matches the positioning in the reference machine used to record the reference data. Consequently, the sensor device more or less eliminates the effects of mechanical irregularities, bearing gaps, and / or mechanical play that lead to machine part positioning errors.

[0030] Recording the carrier positions makes it possible to associate recorded images of light patterns with recorded carrier positions, and thus to associate positions that refer to the coordinate system of a computer-controlled reference machine, such as a laboratory machine, with positions that refer to the coordinate system of another computer-controlled machine, i.e., the computer-controlled machine currently in use. This also makes it possible to produce precise translation and rotation data associated with the pattern generators, which will work together as advanced encoders.

[0031] This invention utilizes a variety of different optical configurations for each available camera, thus enabling the acquisition of composite images with a single camera that simultaneously depict the mechanical state of a multitude of mechanical degrees of freedom and a multitude of machine parts. Since a greater number of optical configurations are also implemented to contribute to the spatial light pattern represented by the composite image, more translations and rotations from more degrees of freedom are measured simultaneously, or higher accuracy is achieved in determining translational and rotational displacements. DETAILED DESCRIPTION OF INVENTION EXAMPLE 1.

[0032] A sensor device 1 According to one embodiment of the invention, with reference to Fig. 1 described. The sensor device 1In this example, it is used for the alignment and calibration of a milling machine. 2 adapted. In Fig. 1 includes the milling machine 2 the work area table 4 , the tool holder 5 , the support parts 100 - 1 , 100 - 2 and 100 - 3 and the carriers 3 - 1 and 3 - 2 In the present example, if the carriers 3 - 1 and 3 - 2 the milling machine 2 Once mounted, their axes must be aligned to be orthogonal to each other. Even after the supports are 3 - 1 and 3 - 2 mechanically set up to align as closely as possible with an internal coordinate system 100 - 4 the milling machine 2Even after alignment, residual errors can still occur when the carriers are moved. These errors must be taken into account if high machining precision is required. The sensor device 1 is used to find these errors. The present embodiment provides these errors as translational and rotational offsets from corresponding reference data obtained using a CMM (coordinate measuring machine). 2-R be recorded separately, as by Fig. 2. These errors are related to the positions of the moving parts of the milling machine. 2 In the present example, the milling machine has an internal 3D machine coordinate system 100-4, to which the X -, Y - and Z -carrier positions (it should be noted that for the sake of simplicity only the X -beam axle 3 - 1 and the Z -beam axle 3 -2 in Fig. (1 shown schematically). The purpose of the present embodiment is to find a set of translational and rotational offset data associated with the respective positions of a set of 3D positions within the working volume of the milling machine. This offset data is used by the machine manufacturer to improve assembly and alignment, or by the CNC (computer numerical control) machine to correct errors in the actual machining process. X - Y - Z -To compensate for carrier movements that physically place the tool into the intended positions in space.

[0033] Fig. Figure 1 shows a schematic drawing of the milling machine. 2 together with an embodiment of the present invention. The sensor device 1 includes two lighting devices 7A and 7B and a camera 9A distinction is made between two optical configurations. 11A and configuration 11B In a configuration where the lighting system 7A to illuminate the pattern generator 6 Once the camera is made operational, it is assumed that the camera 9 belongs to optical configuration A. Accordingly, it is assumed that in a configuration where the lighting device 7B to illuminate the pattern generator 6 When the camera is made operational, it belongs to optical configuration B. The term "illumination device" refers to a specific combination of light source and illumination optics. Consequently, light originating from the same light source but following different optical paths or passing through different optics before or after reaching the pattern generator should also be considered. 6This happens, and includes various "lighting devices". In this example, the lighting devices are... 7A and 7B , as well as the camera 9 on the tool holder 5 attached and the pattern generator 6 is on the workpiece holder 4 attached. It should be noted that another possible setting that would work just as well is one where the first and second lighting devices are attached. 7A , 7B and the camera 9 on the workpiece holder 4 are attached, and the pattern generator 6 on the tool holder 5 is attached. The pattern generator 6 is a light diffuser, such as a piece of material with a light-scattering surface, which is suitable for diffusing at least part of the light emitted by the lighting devices 7A and 7B on the pattern generator in the direction of the camera 9is emitted in a direction towards the camera 9 to return or transfer. This document describes the light diffraction that occurs when light from the pattern generator 6 The phenomenon of light being reflected or transmitted is interchangeably referred to as diffraction, reflection, transmission, or scattering. Lighting devices 7A , 7B are configured, the pattern generator 6 to illuminate in order to create a spatial light pattern 8 somewhere in the space between the workpiece holder 4 and the tool holder 5 to create, in order to enable the spatial light pattern 8 as seen from the camera in the room and in the camera's image plane 9 It can be imaged, and a composite image is captured. According to an optics textbook definition, the space between the workpiece holder 4 and the tool holder 5generally referred to as object space and can be measured from the object plane 15 from negative infinity to positive infinity. Thus, the spatial light pattern encompasses 8 In this example, a first light pattern component 8A in the room, which is illuminated by light from the first lighting fixture 7A is generated, which is scattered into space by the pattern generator, and a second light pattern component 8B in the room, which is illuminated by light from the second lighting device 7B is generated, which is scattered into the same space by the pattern generator, and the composite image that is captured in a single camera recording of the spatial light pattern. 8 is recorded, and through the two components 8A and 8B is formed. Accordingly, the components could 8A and 8BThey may be separated by time, light color, polarization, angle as seen from the light-sensitive surface of the camera, or by other parameters, provided they are both imaged by the same camera in the same camera image. 8A and 8B If separated by angles, the minimum angular distance, measured from the light-sensitive surface of the camera, between the light of the component should be 8A and the light of the component 8Bbe greater than 2*arcsin(lambda / (4*p)), where arcsin() is the trigonometric function, lambda is the wavelength of the light involved, and p is the pixel size of the camera. The terms camera capture, camera exposure, and camera acquisition are used interchangeably here to refer to the camera's ability to capture a still image or a still photograph from a sequence of video frames. The camera is advantageously configured to produce a composite 2D (two-dimensional) image of the spatial light pattern. 8 records.

[0034] The sensor device 1 is configured to capture the composite image in at least one first 11A and one second 11B different optical configuration. The first optical configuration 11A defines the path from the first lighting device 7A via the pattern generator 6 to the camera 9, which in this configuration camera 9A is called the second optical configuration 11B defines the path from the second lighting device 7B via the pattern generator 6 to the camera 9 , which in this configuration camera 9B This is called [missing term]. Each respective optical configuration is thus defined by the relative position of the pattern generator. 6 , the camera 9 and the lighting equipment 7A and 7B Thus, each image captured by the camera is defined. 9 The recorded composite image in the respective sets of different optical configurations, which are marked by the indices A and B respectively, is each unique and directly related to the relative position of the pattern generator. 6 , the camera 9 and the respective lighting equipment 7A and 7B are related.

[0035] In a complete system configuration using the sensor device described above 1 In addition to the sensor device, the system includes 1 also a computer hard drive 10 or a similar data storage device for storing the linked carrier positions 31 and 32 from the milling machine 2 and recorded composite images 30 from the camera 9 In the present embodiment, the optical configuration exposes 11A created light patterns the camera 9 simultaneously with the one in the optical configuration 11B The created light patterns. That is, the recorded composite image. 30 is an image made up of the light pattern components 8A and 8B The computer also contains a processor. The images are formed and captured by the camera in a single camera shot.12 , which is configured to use previously recorded carrier reference position data 31-R and 32-R with the carrier position data 31 , 32 , which are from the milling machine 2 to compare, and each previously recorded first image data of a first reference light pattern. 8A-R and second image data of a second reference light pattern 8B-R , which were recorded in separate camera shots, and which were recorded in each of the different first and second optical configurations, with the recorded data of composite images 30 , which are shown by the camera 9 come to compare.

[0036] The previously recorded carrier reference position data 31-R and 32-R and the previously recorded image data of the first reference light pattern 8A-R and second reference light pattern 8B-R are recorded beforehand in the separate CMM, as by Fig. 2 shown, on the hard drive 10-R saved and stored on the hard drive 10 out of Fig. 1 transferred. In Fig. 2. These data are the collected reference data. 33-R In Fig. 1. The collected data 33 , which are from the processor 12 from the hard drive 10 The collected reference data will be received. 33-R , the carrier position data 31 and 32 and the recorded data of the composite image 30 .

[0037] The first and second lighting devices 7A or 7B is of a type that is able to emit light, which can be used to illuminate the pattern generator 6 is suitable to create the first spatial light pattern component 8A and the second spatial light pattern component 8Bto generate. Generally, lighting devices capable of emitting essentially coherent light are suitable for this purpose. For the purposes of the present invention, the coherence length of a lighting device 7 defined as the maximum optical path length difference that produces a coherence degree greater than 10%. In this particular embodiment, the illumination devices are laser-emitting diodes with a coherence length greater than the largest of the path length differences within each of the optical configurations A and B. Light emitted by each of the illumination devices 7A and 7B The emitted light follows infinitely many different paths. For optical configuration A, in Fig. 3. For illustrative purposes, two examples of the paths are shown. The first path is indicated by the dot-dash line, which is aligned with an optical axis. 16Acoincides with the first lighting device, which is supplied by the first lighting device 7A to the pattern generator 6 runs, and is continued along the dot-dash line, which is connected to an optical axis 20 the camera coincides with the pattern generator 6 to the camera 9 The second path is through the fully drawn double line. 21A specified, which are from the first lighting device 7A to the pattern generator 6 runs, and is along the fully drawn double line. 22A continued, which from the pattern generator to the camera 9 proceeds. By considering all possible optical paths and path lengths from the first lighting device. 7A via the pattern generator 6 to the camera 9 The laser diode source of the lighting device should 7AEmit light with a coherence length greater than the maximum length difference between these optical paths. The same coherence condition should also be met separately by configuration B, which is the second illumination device. 7B , the pattern generator 6 and the camera 9 includes the optical wavelength of the lighting device. 7A However, it should differ sufficiently from the optical wavelength of the lighting device. 7B to differentiate in order to avoid cross-interference between the light pattern components 8A and 8B in the composite image 30 does not appear. The camera 9 The pattern generator is typically an electronic 2D camera of the CCD (charge-coupled device) or CMOS type, preferably with a resolution of 1000x1000 pixels or better. 6is suitably provided by a flat stainless steel plate. Other materials, such as aluminum and glass, could be used within the scope of the invention to form the pattern generator. 6 to provide as long as the reflective surface of the pattern generator 6 to generate the intended spatial light pattern components 8A , 8B is suitable. The pattern generator 6This could also be provided by a reflective hologram, or by a copy of a metal surface pattern vapor-deposited onto a glass plate surface, or by an imprint from a primary surface onto another suitable surface. However, a key requirement is that the surface details should not change over time, for example, due to corrosion, handling, or similar factors. In the present embodiment, the reflective surface of the steel plate has a surface roughness comparable to the laser light wavelength emitted by the illumination devices. 7A , 7B is emitted, resulting in a sufficient angular range of scattering angles and a sufficient amount from the camera. 9 The light produced is detectable. In this embodiment, a computer contains the hard drive. 10 and the processor 12 To obtain the carrier position data 31 or32 To receive the data, the computer is connected to the milling machine (CNC) via an Ethernet cable, and the computer receives composite images. 30 from the camera 9 by using a USB port cable connection or a FireWire port cable connection. The reference position data 31-R or 32-R and the images of the individual reference light pattern 8A-R or 8B-R are expediently taken from the reference data hard drive 10-R to the hard drive 10 , using a USB-type memory stick or similar portable data storage device.

[0038] The following describes a method according to one embodiment of the invention with reference to the Fig. 1, Fig. 2 and Fig. 3 described. The sensor device described above 1 or a sensor device 1-RThe same optical configurations are used to record the reference data stored on the hard drive. 10-R , the storage medium 10-R out of Fig. 2, are stored. To create images of the reference light patterns 8A-R or 8B-R and corresponding reference support position data 31-R or 32-R In the present embodiment, the recording process is performed on a calibrated coordinate measuring machine, hereinafter referred to as the CMM. 2-R This is referred to as CMM. Schematically, it is CMM. 2-R the milling machine 2 similar, but through Fig. Figure 2 is shown. In the present embodiment, this CMM is programmed to move stepwise between scanning positions in a fixed 3D matrix of positions. The number of positions would depend heavily on the user and their application. If the milling machine 2If only the arrangement quality needs to be checked, a 5x5x5 position array may suffice. On the other hand, if detailed feedback and correction data for the CNC are required, a higher number, such as 1000x1000x1000, may be necessary. In this example, these positions cover a volume of 400x400x400 mm. Generally, the distribution of the scanning position can range from a linear 1D arrangement to a 2D matrix, up to the aforementioned 3D matrix, with the positions being advantageously unevenly distributed in some cases. The computer hard drive stores data for each of these positions. 10-R two images 8(49A-R, 49B-R), one for each optical configuration 11AR , 11B-R , together with the corresponding carrier position data 31-RA , 32-RA , 31-RB and 32-RB Assuming that the CMM is mechanically stable during image acquisition, the carrier position is 31-RA equal to the carrier position 31-RB and the carrier position 32-RA is equal to the carrier position 32-RB This data serves as the reference data for the subsequent production / service alignment activities of the milling machine. 2 and are removed from the hard drive in a timely manner 10-R ( Fig. 2) to the hard drive 10 ( Fig. 1) transferred. The light sources (not shown in the figures) of the first and second lighting devices 7A-R , 7B-R are laser diodes of the same type and coherence characteristics, for later use in the milling machine 2 to be used. In the present embodiment, and as in Fig. 2 schematically indicated, and also according to the configuration of the milling machine in Fig. 1, represents the first lighting device 7A-R focused light with its focus position, which is also its divergence center 17A-R is, and which is located between the first lighting device 7A-R and the pattern generator 6-R It is located, ready. The laser light diverges from this divergence center. 17A-R to the pattern generator 6-R The second lighting device 7B-R , as also schematically in Fig. 1, specified, contains optics to provide collimated light that is directed to the pattern generator 6-R spreads. That is, its center of divergence. 17B-R In this example, is set to infinity and therefore cannot be within the extent of the drawing of Fig. 2 will be shown. Fig. Figure 3 schematically shows the illumination / observation geometries of the two optical configurations A and B and represents the optical configurations that are used on both the milling machine. 2 , schematically represented by the drawing of Fig. 1, as well as on the CMM 2-R , schematically represented by the drawing of Fig. 2. For clarity, both centers of divergence will be used. 17A-R and 17B-R , according to the centers of divergence 17A and 17B , within the dimensions of Fig. 3 shown, although the divergence center 17B the second lighting device 7B in the present embodiment, is set to infinity. As also in Fig. As shown in Figure 3, the imaging characteristics of the camera depend on an object plane position and size 15 and a corresponding depth of field. 19 , which is centered on this object plane. The depth of field extends from this plane. 19 - 1 corresponding to the level 19 -2. In the present example, the object plane is located between the camera 9 and the pattern generator 6 The optical axis of the camera 20is defined as passing through two points in space, where the first point is the center of the camera's entrance lens 9 is and the second point is the center of the object plane 15 is. The optical axis of the camera 20 extends to a point 23 to define where the optical axis 20 the camera 9 the pattern generator 6 hits. As in Fig. Figure 3 shows the optical characteristics of the lighting devices from their respective centers of divergence. 17A and 17B and a corresponding depth of field 18A and 18B , which are centered on these respective centers of divergence. The depth of field of lighting equipment 7A extends from the plain 18A1 to the level 18A2 Accordingly, the depth of field of the lighting device extends 7B from the plain 18B1to the level 18B2 For the sake of clarity, the centers of divergence in the present example are located between the respective lighting devices. 7A , 7B and the pattern generator 6 Each of the optical axes of the lighting devices 16A , 16B is defined as passing through two points in space, their respective centers of divergence 17A , 17B , to that point 23 , at which the optical axis 20 the camera's pattern generator 6 The divergence center distances diA 40, diB 41 of the lighting device are measured along their respective optical axes. 16A , 16B from the divergence centers 17A , 17B to the reflection surface point 23 on the pattern generator 6 The object plane distances dcA 42, dcB 43 of the camera are equal in the present example and are measured along the optical axis. 20from the reflection surface point 23 on the pattern generator 6 to the object level 15 measured. It should be noted that these geometries changed during the CMM reference recording. 2-R and measurements of the milling machine 2 change when the CMM carriers 3 - 1-R , 3 - 2-R and milling machine carrier 3 - 1 , 3 - 2 move. The defined axes, positions, and distances will change during these processes. The effective distance from the first optical configuration A is given by the equation deA = diA*dcA / (diA+dcA), and in the same way, the effective distance from the second optical configuration B is given by the equation deB = diB*dcB / (diB+dcB). If the pattern generator 6If the reflector is curved or contains a lensing effect during transmission, diA and diB in the above equations should be replaced by the respective equations diA*f / (diA+f) and diB*f / (diB+f), where f represents the equivalent focal length of an equivalent pattern generator, where the surface of the pattern generator 6 is replaced by an optically smooth surface without roughness. If the pattern generator 6 For example, if the optical system is curved with a radius of curvature of R, the focal length f would be equal to R / 2. For each of these optical configurations, the depth of field defines a region within which an object is assumed to be in focus. In this example, these regions extend from the respective field plane. 19 - 1 to the field level 19 - 2, whereby the object plane spacing dcA 42, dcB 43 ranges from dcA1=dcB1 to dcA2=dcB2. Accordingly, the lighting devices can cover various distances from the respective divergence plane. 18A1 until 18A2 , and from 18B1 until 18B2 , sufficient, whereby the divergence center distances diA 40, diB 41 of each diA1 until diA2 and diB1 until diB2 sufficient. Used for dcA1 , diA1 , dcA2 and diA2 Substituting the equation for the first effective distance deA into the equation yields a range of effective distances that differ from deA1 until deA2 extend. Accordingly, if for dcB1 , diB1 , dcB2 and diB2 Substituting deB into the equation for the first effective distance yields a range of effective distances that differ from deB1 until deB2 extend. Typically, the depth of field involved for the cameras and lighting equipment is + / -(2*Lambda*F*F), where Lambda is the optical wavelength and F is the effective optical F-number, which refers to the pattern generator. 6 The effective F-number refers to the F-numbers that define the angular measure of the exit lenses of the lighting equipment and the entry lenses of the camera using the equation F = 1 / [2*sin(v / 2)], where v is the angular measure of these lenses as observed from the divergence centers and object planes. It should be noted, however, that the lighting equipment and the camera may be configured with different F-numbers. It should also be noted that the lighting equipment 7A , 7B alternative optical configurations may contain astigmatic foci, so that the divergence centers 17A , 17B at various lighting device distances diA (40 in Fig. 3) and diB (41 in Fig. 3) can be, when observed in a transverse direction approximately parallel to the X-axis, and to the corresponding divergence center distances when observed in orthogonal transverse directions. In other alternative optical configurations, the same applies to the imaging properties of the camera, which determine the object plane position. 15A and 15B at different object plane distances dcA (42 in Fig. 3) and dcB (43 in Fig. 3) Position the camera when focused on the features in two orthogonal transverse directions. Astigmatic performance is typically achieved by incorporating cylindrical optics into the illumination setup and / or observation paths. Optical configurations A and B are configured such that their effective distances do not overlap, i.e., for each location of the sensor device 1should any effective distances that are deA1 until deA2 sufficient, not necessarily to any distances that are from deB1 until deB2 Sufficient, to be. If alternative optical configurations have astigmatic divergence centers. 17A , 17B or astigmatic object plane positions 15A , 15B The requirement is that the effective distance for optical configurations A and B should not overlap for each of the separately evaluated transverse directions. For improved image analysis performance, the range of effective distances should be separated, as increasing the distance between them makes it easier to distinguish between translational and rotational offsets, thereby reducing the influence of measurement errors.

[0039] Since the pattern generator 6When illuminated by coherent laser light, a structurally stable spatial light pattern is produced. 8 in the 3D space above the pattern generator 6 This spatial light pattern is created. 8 is done using the camera 9 observed. Each of the optical configurations A and B produces a light pattern that differs from the other. These light patterns are typically unique for all the different recording positions. If the carriers 3 - 1 , 3 - 2 and 3 - 1-R , 3 - 2-R be controlled to be at a first recording position at a first time T1 to record, then be moved to record at subsequent recording positions, and finally be moved back to exactly the first position at a second time point in time. T2 To record an image, the image of the light patterns that were present at the time will be captured. T1were recorded at the time T2 exactly reproduced. But even very small positional offsets between the first and second recording times, such as 0.01 µm, can affect the light pattern positions and are therefore detectable.

[0040] Once the CMM reference recordings are complete, the collected reference data will be 33-R , which are on the hard drive 10-R were recorded using the sensor device 1-R according to the present embodiment or a similarly optically configured sensor device 1 , used to correct misalignments during assembly, use, or maintenance of the milling machine 2 to quantify. Once quantified, the misalignments are used to align the machine and / or control subsequent CNC movements of the milling machine. 2to improve positioning. This results in better positioning independent of any mechanical translational and rotational irregularities in the milling machine. 2 This results in deviations that cannot be corrected using conventional calibration and alignment methods. The sensor device 1 , which contains the same optical configurations A, B as used in the recording of the reference data from CMM 2-R were used, will be used. Fig. Figure 1 shows a schematic representation of the milling machine. 2 In the present embodiment, the pattern generator 6-R moved to the milling machine and the pattern generator 6 called. But the present embodiment would work just as well if both the pattern generator 6-R as well as the pattern generator 6 They are exact copies of the same original. The new positions of the lighting setup and camera arrangement.7A , 9 , 7B relative to the pattern generator 6 They should reproduce the CMM machine's results as accurately as possible. To achieve this, the lighting setup and camera arrangement must be optimized. 7A , 9 , 7B and the pattern generator 6 It must be pre-aligned. For this purpose, the use of pre-positioned mechanical locators or an iterative mechanical alignment of the pattern generator's position is necessary. 6 to be carried out. The CNC control of the milling machine. 2 is then used to configure the lighting setup and camera arrangement. 7A , 9 , 7B into the neighborhoods of one of the previously recorded CMM positions 2-R relative to the pattern generator 6 to move, then to visually observe / measure the offsets, then the pattern generator 6to move it mechanically and then repeat the alignment process until the positions are reasonably aligned. Alternatively, it is possible to adjust the lighting setup-camera arrangement. 7A , 9 , 7B relative to the pattern generator 6 Mechanical alignment is achieved by manually using rulers / probes or other alignment tools such as a touch probe or similar. After pre-alignment, this setting of the milling machine is required. 2 ready to find their exact alignment, as relative to the reference records of the CMM 2-R measured. The collected reference data 33-R , represented by the series of corresponding reference support position data 31-R , 32-R and pictures 49A-R , 49B-R , which contain the reference light pattern data 8A-R , 8B-R They are displayed on the hard drive. 10 copied. The milling machine 2is then instructed to step nominally between the previous nominal positions that correspond to those defined by the reference CMM. 2-R were recorded. For each of these positions, the computer hard drive receives 10 from the camera 9 the composite images 30 from the spatial light patterns 8 and the corresponding carrier positions 31 , 32 , which occur simultaneously with each of the composite images 30 were recorded. For each of these composite images, the spatial light pattern is recorded. 8 in the various configurations 11A , 11B formed. The translation and rotation of the lighting device-camera arrangement. 7A , 9 , 7B relative to the translation and rotation of the pattern generator 6 should be nominally equal to the corresponding value during the reference recordings of the CMM 2-RThe translation and rotation used will be the result. Consequently, the new composite image of the spatial light pattern will be generated for all positions. 8 , which is in the milling machine 2 A picture of the combined light pattern components was recorded. 8A or 8B Each of the light pattern components 8A and 8B will be shown separately according to the corresponding reference light patterns. 8A-R or 8B-R the CMM 2-R be similar. In particular, the light pattern image representations contain data that are similar enough to be recognized as the same light pattern representations, but with some offset and possible minor decorrelation. Regarding the light-sensitive surface of the camera. 9 The images of the light pattern components will be displayed 8A and 8B However, generally with relatively small amounts compared to the images of the respective reference light patterns 8A-R and 8B-R The image may be shifted. With reference to the light-sensitive surface, this is referred to as 2D light pattern translation offsets (DAX, DAY) or (DBX, DBY). To calculate these offset data, each recorded reference image must be... 49A-R , 49B-R of each one of the reference light patterns 8A-R and 8B-R with the corresponding composite image 30 the milling machine 2 Mathematically 2D cross-correlated (for a cross-correlation calculation of images, see, for example, the book by Athanasios Papoulis, entitled Systems and Transforms with Applications in Optics, 1968, McGraw-Hill Book Company, New York). This arrangement, in which the composite image 30 of the spatial light pattern 8 , consisting of the spatial light pattern components 8A and 8B , where the data of composite images are present in both the optical configurations 11AWhen both 11B and 11B are formed, errors due to laser wavelength and mechanical drift are reduced to a minimum. For each of the carrier positions 31 and 32 determine the positions that lead to a 2D cross-correlation maximum, the image offsets ( DAX , DAY ) and ( DBX , DBY ) of the two optical configurations A and B. Since the encoders of the reference CMM-2-R carriers 3-1-R, 3-2-R have slightly different carrier positions. 31-R , 32-R from the assigned carrier positions 31 , 32 the carrier 3 - 1 , 3 - 2 the machine 2To be able to return the correct image translation offset, the carrier positions or the measured light pattern translation offset should be corrected for these possible differences, even for the same nominal carrier positions. In the present example, these corrections are applied to the data representing the light pattern translation offsets, and the corresponding corrected image translation offset ( dAx , dAy ) and ( dBx , dBy ). These corrected image translation offsets are achieved through a combination of translation offsets ( Dx , Dy ) and rotation angle offsets ( Tx , Ty ) the lighting setup-camera arrangement 7A , 9 , 7B relative to the pattern generator 6 caused. That is, the corrected image translation offsets are caused by translation offsets ( Dx , Dy ) and rotation angle offsets ( Tx , Ty ) of the workpiece holder4 the milling machine 2 relative to the tool holder 5 caused, using the first sub-position 4-R relative to the second sub-position 5-R the CMM 2-R as references. Dx and Dy The translation offsets are placed in the x- or y-direction, where Tx and Ty Rotation angle offsets around the x - and y -axis. These offsets refer to the milling machine's coordinate axis. 100 - 4 from Fig. 1. The reference support positions 31-R , 32-R refer to the coordinate axis 100 - 4-R the CMM 2-R .

[0041] In a linear approximation, the relationship between the image translation offsets (dAx, dAy) and (dBx, dBy) and the relative partial translation offsets (Dx, Dy) and rotation angle offsets (Tx, Ty) is expressed by the four equations dAx=m11*Dx+m12*Dy+m13*Tx+m14*Ty, dAy=m21*Dx+m22*Dy+m23*Tx+m24*Ty, dBx=m31*Dx+m32*Dy+m33*Tx+m34*Ty, dBy=m41*Dx+m42*Dy+m43*Tx+m44*Ty. In these equations, the respective factors (m11, m12, m13, m14, m21, m22, m23, m24, m31, m32, m33, m34, m41, m42, m43, m44) are given by the exact illumination and observation geometries of the first and second optical configurations A and B, respectively. Optics textbooks calculate these factors using diffraction formulas, where a given spatial frequency of a specific reflection / transmission object, which deflects light from a given illumination direction to a given observation direction, is given by the difference between the observation and incident wave vectors.Variations of these formulas are often also referred to as grating equations. As long as the effective distance deA for generating the light patterns... 8A , 8A-R the optical configuration A from the effective distance deB to generate the light patterns 8B , 8B-R If the optical configuration B differs, the above equations are then reversed to determine the translational and rotational angle offsets of the workpiece holder. 4 relative to the tool holder 5 to find out how to determine the translation offset values ​​( Dx , Dy ) and rotation angle offsets ( Tx , Ty ). As a numerical example, it is assumed that the illumination distance diA 40 is equal to 60 mm, the camera distance dcA 42 is equal to 100 mm, the illumination distance diB 41 is at infinity, the camera distance dcB 43 is also equal to 100 mm, the coordinate axis XYZ parallel to the corresponding XYZ -coordinate axis 100 - 4 ( Fig. 1) the milling machine 2 is and the origin at that point 23 ( Fig. 3) is placed where the optical axis 20 the camera 9 the pattern generator 6 This applies. For numbers representing the distances, see... Fig. 3. It is assumed that the optical axes of the lighting devices 16A , 16B coaxial with the optical axes of the camera 20 are that the camera magnification is equal to -1 / 3 and that the X - and Y -axis of the light-sensitive camera surface parallel to the corresponding X - and Y -Axes of the machines are, as defined by the milling machine coordinate axis 100 - 4 ( Fig. 1) and CMM coordinate axis 100 - 4-R ( Fig. 2) specified. Coaxial axes mean that the axes involved are parallel. In this case, the illumination direction points opposite to the observation direction. For pattern generators illuminated by coaxial transmission axes, this would mean that the illumination direction is the same as the observation direction. In a linear approximation, these configuration parameters for the factors (m11, m12, m13, m14, m21, m22, m23, m24, m31, m32, m33, m34, m41, m42, m43, m44) would yield the respective values ​​(-0.8889, 0.0, 0.0 mm, -66.667 mm, 0, -0.8889, 66.6667 mm, 0.0 mm, -0.3333, 0.0, 0.0 mm, -66.6667 mm, 0.0, -0.3333, 66.6667 mm, 0.0 mm). It is assumed that no corrections are necessary due to the difference between the corresponding support positions. 31 , 32 and reference carrier positions 31-R , 32-Rare present. Then it is determined that the corrected image translation offsets (dAx, dAy, dBx, dBy) are each equal to (-59.6, -4.0, -30.7, +2.7 µm). These expressions can then be inverted to find the desired values ​​for the respective translation offsets ( Dx , Dy ) as (52.0, 12.0) µm and rotation angle offsets ( Tx , Ty ) as (100, 200) µ radians. The linear expressions described above describe the optical illumination, diffraction, and observation processes. In real-world applications where translational and rotational offsets are large, the m-factors described above may need to account for additional nonlinear deviations. Alternatively, the complete nonlinear equations can be iterated to find the exact solution.

[0042] The translation and rotation data 34 , which are determined by the carrier positions 31 , 32, the associated partial translation offsets ( Dx , Dy The values ​​shown (Tx, Ty) and associated rotation angle offsets become the calibration data for subsequent production, maintenance, or alignment activities of the milling machine. Alternatively, the CNC of the milling machine uses 2 this data to compensate for the error movements of the carriers 3 - 1 , 3 - 2 during milling. EXAMPLE 2.

[0043] A sensor device 1 According to one embodiment of the invention, with reference to the Fig. 4 and Fig. 5 described. In general, two optical configurations A and B are required to simultaneously locate the translational and rotational components separately. However, although two different optical configurations are provided in Example 1, a higher number of optical configurations could be provided in further embodiments. A higher number of optical configurations provides more information and a greater number of spatial references, but also requires greater computational capacity to analyze recorded data. The exact setting of the optical configurations is varied within the scope of the invention, provided the light pattern is repeatable, so that it is always reproduced. An example, with which all 6 degrees of freedom ( 3 Translations + 3 rotations) of a rigid body motion for all applied support positions 31 , 32can be found in the Fig. 4 and Fig. 5 schematically represented. Fig. 5 shows details of an arrangement 60 , which in Fig. 4 (dashed line) on the machine part 5 is attached. Fig. Figure 5 schematically shows a setting with four optical configurations. 11A , 11B , 11C , 11D , which together comprise four light pattern components 8A , 8B , 8C , 8D form, which are captured by the camera 9 in the composite image 30 to be recorded. For clarity, the outline / edge of the various lighting fixtures will be shown. 7 this embodiment in Fig. 5 are not shown, but their components can be listed by following the paths of the corresponding configurations. 11 follows, including their common light source 52In the present example, the light follows the configuration 11A the path from the light source 52 via the beam splitter 50 - 1 , beam splitter 50 - 2 , Mirror 51 -1, Pattern Generator 6 , Mirror 51 - 4 to the camera 9 The light of the configuration 11B follows the path from the light source 52 via the beam splitter 50 - 1 , beam splitter 50 - 2 , Pattern generator 6 , Mirror 51 - 4 to the camera 9 The light of the configuration 11C follows the path from the light source 52 via the beam splitter 50 - 1 , Mirror 51 - 2 , beam splitter 50 - 3 , Pattern generator 6 to the camera 9 The light of the configuration 11D follows the path from the light source 52 via the beam splitter50 - 1 , Mirror 51 - 2 , beam splitter 50 - 3 , Mirror 51 - 3 , Pattern generator 6 to the camera 9 In the present example, the beam splitter divides 50 - 1 the light is neutral 50-50% with respect to the polarization state, while the beam splitters 50 - 2 and 50 - 3 These are polarizing cube beam splitters that can split light into orthogonally linearly polarized light. Provided that the pattern generator... 6 Acting as a polarization-preserving reflector, this arrangement can reduce the light entering the camera. 9 in the configuration 11A achieved, configured so that it is orthogonally polarized compared to light that the camera in the configuration 11B achieved. Likewise, the light that the camera receives is 6 via configuration 11Cachieved, arranged in such a way that it is orthogonally polarized, compared to the light which follows the path of the configuration 11D This arrangement of cross-interference between light following the path of the configuration. 11A follows, relative to light, the path of the configuration 11B follows, reduced to a minimum and does not appear in the composite image. 30 . Likewise, this arrangement prevents cross-interference between light traveling along the paths of the configurations. 11A and 11B follows, relative to light, the paths of the configurations 11C and 11D follows, reduced to a minimum and does not appear in the composite image. 30 . Due to the angles 61 between the light that follows the paths of the configurations ( 11A , 11B) follows, relative to the light, the paths of the configurations ( 11C , 11D)Following this, the cross-interference between the light pattern components will be 8A and one of the light pattern components 8C and 8D and the cross-interference between the light pattern component 8B and one of the light pattern components 8C and 8D from the camera 9 not resolved. That is, converted to the light-sensitive surface of the camera, the converted angles should 61 for all light that follows the paths of configurations ( 11A , 11B) follows, relative to the light, the paths of the configurations ( 11C , 11D) It follows that the result is greater than 2*arcsin(lambda / (4*p)), where arcsin() is the trigonometric function, lambda is the wavelength of the light involved, and p is the pixel size of the camera. Due to the camera's internal optics... 9 , which in Fig. 5 is not shown, the position 15 the object level is divided and into Fig. 5 is specified as 15-1 and 15-2, where the object level 15 - 1 the object level of the configurations 11A and 11B is and the object level 15 - 2 the object level of the configurations 11C and 11D is. To determine the reference support positions 31-R and 32-R and images of the reference light patterns 8A-R , 8B-R , 8C-R and 8D-R to record the arrangement of Fig. 5 together with the pattern generator 6 in a machine with carriers similar to those in Fig. The four schematically shown positions are used. During the reference recording stages, the images of the reference light patterns are captured. 8A-R , 8B-R , 8C-R and 8D-R separately recorded in series. This is achieved through the use of aperture shutters (not in Fig. 5 shown) is achieved to allow the camera to capture these as separate images. 49A-R , 49B -R, 49C-R and 49D-R. Through the calculations described in Example 1, using the reference beam positions. 31-R , 32-R , the images of the reference light patterns 8A-R and 8B-R , of the composite image 30 and the carrier position 31 and 32 Is it possible to isolate two translational and two rotational components of the total 6 rigid body movements of the machine part? 4 relative to the machine part 5 and with respect to the coordinate axis ( X1 , Y1 , Z1 ) to find. The calculations described in Example 1 make the use of the reference beam positions possible. 31-R , 32-R , the images of the reference light patterns 49C-R and 49D-R , of the composite image 30 and the carrier position 31 and 32, two further translational and two further rotational components of the total 6 degrees of freedom of the movement of the machine part 4 relative to the machine part 5 , but now in relation to the coordinate axis ( X2 , Y2 , Z2 ) to find. This results in a total of 8 components, 2 of which are redundant, in the calculation of the 6 degrees of freedom of the rigid body motion between the machine part. 4 and 5 . EXAMPLE 3.

[0044] A sensor device 1 According to one embodiment of the invention, with reference to the Fig. 6 and Fig. 7 described. Fig. Figure 6 shows a setting where details of the lighting equipment ( 7 ) in Fig. 7 are shown in more detail. In this embodiment, as also described in Examples 1 and 2, a spatial light pattern ( 8) produced from light generated by the lighting devices ( 7 ) originates from the pattern generator ( 6 ) is reflected and the camera ( 9 ). Additionally, further “internal” pattern generators ( 54C , 54D) , internally to the respective lighting devices ( 7A , 7B) , added. This creates a total of four configurations ( 11A , 11B , 11C , 11D) , whose configurations ( 11C , 11D) These internal pattern generators ( 54C , 54D) reflected light serves to distinguish light pattern components ( 57C , 57D) to generate that are not caused by the relative translation / rotation between machine parts ( 4 ) and ( 5 ) are affected. But they are not affected by internal changes in the lighting equipment ( 7 ) and the camera ( 9) influenced by the respective wavelength drift of the light sources ( 52A , 52B) and the positional drift of the camera's light-sensitive surface is caused. In this example, the light sources ( 52A , 52B) Diode lasers. The wavelength of diode lasers can vary slightly, particularly due to temperature drift and laser mode transitions, typically in the nano- and sub-nanometer range. This wavelength drift reduces the overall accuracy of the sensor device. 1 , as described in Examples 1 and 2. A key feature of the present invention is the ability to separately capture images of reference light patterns and store them for later comparison with composite images, wherein some or all of the light patterns expose the photosensitive surface of the camera to generate composite images. In the present example, a sensor device is used.1 , which, as in the Fig. 6 and Fig. The configuration specified in section 7 is placed in a laboratory reference machine. This laboratory machine contains temperature-stabilized laser diodes as well as particularly robust mechanics and position encoders. This machine moves a machine part ( 4-R) relative to a machine part ( 5-R) stepwise in volume x-y-z and separately takes images of the reference light pattern ( 8A-R) , of the reference light pattern ( 8B-R) , of the light pattern ( 57C -R) and the light pattern ( 57D-R) For each position of the machine parts, the laboratory reference machine is configured to capture the four images in sequence as quickly as possible to avoid drift. These images are stored on a reference hard drive ( 10-R) saved. The reference light pattern ( 8A-R) is generated by light that follows the path from the light source ( 52A) and via the beam splitter ( 50 - 1), Pattern Generator ( 6 ), beam splitter ( 50 -4), beam splitter ( 50 - 2 ) and to the camera ( 9 ) follows. The reference light pattern ( 8B-R) is generated by light that follows the path from the light source ( 52B) and via the beam splitter ( 50 - 3 ), Pattern Generator ( 6 ), beam splitter ( 50 - 4 ), beam splitter ( 50 - 2 ) and to the camera ( 9 ) follows. The reference light pattern ( 57C-R) is generated by light that follows the path from the light source ( 52A) and via the beam splitter ( 50 - 1 ), Pattern Generator ( 54-C) , beam splitter ( 50 - 2 ) and to the camera ( 9 ) follows. The reference light pattern ( 57D-R) is generated by light that follows the path from the light source ( 52B) and via the beam splitter ( 50 - 3 ), Pattern Generator ( 54D) , beam splitter ( 50 - 4), beam splitter ( 50 - 2 ) and to the camera ( 9 ) follows. The circles ( 50 - 1 , 50 - 2 , 50 - 3 , 50 - 4 ) in Fig. 7 represent beam splitters. To avoid this during a later operation, in which the composite image of the entire spatial light pattern ( 8 ) is recorded, the cross-interference between one of the different light pattern components ( 8A , 8B) and light pattern components ( 57C , 57D) in the composite image ( 30 ) appears, the two laser diodes work ( 52A) and ( 52B ) with slightly different wavelengths and the beam splitters ( 50 - 1 ) and ( 50-3 ) are linearly polarizing beam splitters. Additionally, the pattern generator ( 6 ) and the internal pattern generators ( 54C , 54D)Metallic reflectors that maintain linear polarization states. The beam splitters ( 50 - 2 , 50 - 4 ) are neutral with respect to the polarization directions, which split the light equally independently of the different polarization directions. In Fig. 7 are also the four different object levels ( 15A , 15B , 15C , 15D) the camera ( 9 ) shown. As described in more detail in Example 1 and designated as "de", the distances of these object layers to the respective pattern generator ( 6 ) and internal pattern generators ( 54C , 54D) the respective calculations of the effective distances are included. Likewise, the distances of the four different illumination divergence centers to the respective pattern generator are also taken into account ( 6 ) and to internal pattern generators ( 54C , 54D), designated as “di”, are included in the respective calculations of the effective distances. For the sake of simplicity, it is assumed in the present embodiment that for the lighting device ( 7A) and camera ( 9 ) the relative illumination and observation directions, distances and the effective distance to the pattern generator ( 6 ) with the relative illumination and observation directions, distances and the effective distance to the pattern generator ( 54C) are the same. It is also assumed that for the lighting system ( 7B) and camera ( 9 ) the relative illumination and observation directions, distances and the effective distance to the pattern generator ( 6 ) with the relative illumination and observation directions, distances and the effective distance to the internal pattern generator ( 54D) are the same. To reduce the wavelength drift of the laser diode ( 52A)This makes it possible to later easily compensate for the translational shift of the light pattern component ( 57C) opposite the light pattern position ( 57C-R) from the corresponding translational shift of the light pattern component ( 8A) relative to the reference light pattern position ( 8A-R) to subtract and subtract the configuration D positions accordingly from the configuration B positions before the corrected image translation offset for ( dAx , dAy ) and ( dBx , dBy ) is calculated as described in Example 1.

[0045] The sensor device 1 According to the present embodiment, it can be used for various applications, such as an encoder in a mechanical translation stage or a robot arm. In the present example, it is assumed that it is used in an EDM machine (electrical discharge machine), as in Fig. Figure 6 is shown schematically. In order to operate the sensor device effectively, the EDM machine is designed such that the sensor device 1 approximately the same relative positions between the machine parts ( 4 ) and (5) is moved as they were recorded during the reference recordings to find their exact new offsets as determined by the values ​​of the translation offsets ( Dx , Dy ) and rotation angle offsets ( Tx , Ty ) can be expressed. But unlike the images captured during the reference recordings, composite images ( 30 ) of the spatial light pattern ( 8 ) now from the camera ( 9 ) recorded. The spatial light pattern ( 8 ) is determined by the two external configurations ( 11A , 11B) and the two internal configurations ( 11C , 11D)formed. This ensures that possible mechanical and laser drifts are eliminated, since the states of the two configurations ( 11A) and (11B), and by introducing the configurations ( 11C , 11D) the states of the exact laser wavelengths and camera positions ( 9 ) of the two paths, are recorded simultaneously. Since the corresponding reference light patterns ( 8A-R , 8B -R) and internal reference light pattern ( 8C-R , 8D-R) all were captured as separate images, by processing each of these four images separately with the one used by all four configurations ( 11A , 11B , 11C , 11D) formed composite image ( 30 ) was correlated, the corrected image translation offset for ( dAx , dAy ) and ( dBx , dBy ) found how to find the translation offsets ( Dx , Dy ) and rotation angle offsets ( Tx , Ty ) between the machine parts ( 4 ) and (5) are required. See Example 1 for a description of the calculation procedure ( Dx , Dy , Tx , Ty ) from the values ​​( dAx , dAy , dBx , dBy ).

[0046] This example describes how a small drift in the light source wavelength, small positional changes of the internal optical components, or small positional shifts of the camera can be compensated for by adding internal configurations to form light patterns and by ensuring that the camera ( 9 ) a composite image ( 30 ) of the spatial light pattern ( 8 ). In another patent application PCT / NO2015 / 050102, Gudmunn Slettemoen also describes how the translational offsets ( dAx , dAy ) and ( dBx , dBy ) between at least two images in at least two configurations A and B can be combined to reduce the translation offsets ( Dx , Dy ) and rotation angle offsets ( Tx , Ty ) Values ​​between two machine parts ( 4 ) and ( 5 ). By adding configurations that generate internal reference paths to any of the configurations described in patent application PCT / NO2015 / 050102, a small drift of the light source wavelength, small position changes of the internal optical components, or small positional shifts of the light-sensitive camera surface can also be compensated for in these configurations according to the embodiment described in the present example. QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] EP 1924400

[0007] NO 2015 / 050102 PCT [0009, 0026, 0046] Cited non-patent literature

[0000] Christopher J. Dainty ed. in Laser Speckle and Related Phenomena, Springer Verlag, Berlin 1974

[0005] Ichirou Yamaguchi et al. in Applied Optics, Vol. 28, No. 20, October 15, 1989

[0006]

Claims

[1] Sensor device (1) for a computer-controlled machine (2) with a movable carrier (3) for changing the position of a first machine part (4) relative to that of a second machine part (5), wherein the sensor device (1) comprises the following: a pattern generator (6) that can be attached to the first machine part (4), a first lighting device with coherent light (7-1) and a second lighting device with coherent light (7-1), both of which can be attached to the second machine part (5) and which are optically configured to illuminate the pattern generator (6) with coherent light in order to produce a spatial light pattern (8), a camera (9) that can be attached to the second machine part (5) and that is optically configured to record a composite image (30) of the spatial light pattern (8), wherein the sensor device (1) can be configured such that the camera (9) is able to capture a first composite image of the spatial light pattern (8) in a first camera shot, using a combination of the camera and the first (7-1) coherent light illumination device and the second (7-2) coherent light illumination device, wherein a range of effective optical distances of a first optical configuration (11A), in which light is transmitted along optical paths from the first illumination device (7-1) via the pattern generator (6) to the camera to generate a first spatial light pattern component (8A) of the spatial light pattern (8), is not intersected with a range of effective optical distances of a second optical configuration (11B),in which light is transmitted along optical paths from the second illumination device (7-2) via the pattern generator (6) to the camera to generate a second spatial light pattern component (8B) of the spatial light pattern (8), overlaps, and , wherein each of the first (7-1) and second (7-2) illumination devices is configured to illuminate the pattern generator (6) with coherent light of a coherence length greater than a maximum optical path length difference within each of the first (11A) and second (11B) optical configurations. [2] Sensor device (1) according to claim 1, wherein the sensor device (1) in at least one of the first (11A) and the second (11B) optical configuration comprises means to avoid optical cross-interference between the first component (8A) and the second component (8B) in the composite image (30), wherein the means is at least one of the following: a) a laser in the first coherent light illumination device (7-1) having a wavelength different from the wavelength of a laser used in the second coherent light illumination device (7-2), b) polarizing optics such as polarizers, wave plates, birefringent prisms and polarizing cube beam splitters in the optical paths of optical configurations (11A) and (11B) to make the polarization state of the light of the first component orthogonal to the polarization state of the light of the second component, c) an optical component arrangement which allows the light of the optical configuration (11A) to enter the light-sensitive surface of the camera (9) at angles sufficiently different from the light of the optical configuration (11B) so that the optical cross-interference between the first component (8A) and the second component (8B) is not resolved by the camera (9), and d) Aperture shutters, deflectors or amplitude modulators in the optical paths of the optical configurations (11A) and (11B) to cause the illumination device (7-1) to produce light which exposes the light-sensitive surface of the camera at different times within the exposure time span of the composite image compared to the light illumination device (7-2). [3] Sensor device (1) according to claim 1, wherein the sensor device can be configured such that the camera is able to take a second image of the first component (8A) of the spatial light pattern (8) in a second camera recording and a third image of the second component (8B) of the spatial light pattern (8) in a third camera recording. [4] Sensor device (1) according to claim 1, wherein at least one illumination device of the first (7-1) and the second (7-2) illumination device includes an internal pattern generator (54) arranged such that light follows the path from a light source (52) of the at least one illumination device via the internal pattern generator (54) to the camera (9), thereby generating a third spatial light pattern component (57) of the spatial light pattern (8), and wherein the camera is enabled to capture the composite image (30) of the spatial light pattern (8), which also includes the third component (57), in the first single camera image. [5] Sensor device (1) according to one of claims 1 to 4, wherein the camera is arranged to capture the composite image (30) composed by jointly imaging a plurality of spatial light patterns (8) in a single camera image. [6] Sensor device according to claim 1, wherein a light-sensitive part of the camera (9) is a one-dimensional, 1D, line scan camera sensor arrangement. [7] Sensor device according to claim 1, wherein the light-sensitive part of the camera (9) is a two-dimensional, 2D, line scan camera sensor arrangement. [8] Sensor device according to claim 1, wherein the camera (9) is designed to capture a one-dimensional, 1D, high-speed line image or a two-dimensional, 2D, area image at a frame rate of at least 1000 per second. [9] Sensor device according to claim 1, wherein in an optical configuration (11) the optical axis of the lighting device (7) is coaxial with an optical axis of the camera (9) of the same optical configuration (11). [10] System for determining the position of a machine part in a computer-controlled machine (2) with a movable carrier (3) for changing the position of a first machine part (4) relative to a second machine part (5), comprising a sensor device (1) according to one of the preceding claims, a data storage device (10) designed to store the following a) Reference image data of first (8A) and second (8B) spatial light pattern component images, which are recorded separately with the sensor device (1) in a reference machine, wherein the movable carrier is a corresponding movable reference carrier (3-1-R, 3-2-R), and b) Reference position data (31-R, 32-R) of the reference support associated with the reference image data, and a processing means (12) which is connected to the sensor device and the storage means and is configured to determine a match between the composite image data transmitted by the sensor device and the reference image data transmitted by the storage means in order to derive light pattern translation offset data for a pair of corresponding composite image and reference image data, and to derive translation and rotation data for reading the position or calibrating the computer-controlled machine (2) based on light pattern translation offset data associated with a variety of different optical configurations (11). [11] Method for detecting the translation and rotation of a first part relative to the translation and rotation of a second part of a computer-controlled machine with at least one movable support (3) for changing the position of the first machine part relative to that of the second machine part, the method comprising the following Providing a pattern generator (6) that can be attached to the first machine part (4), Providing a first coherent light illumination device (7-1) and a second coherent light illumination device (7-1), both of which are attachable to the second machine part (5) and are optically configured to illuminate the pattern generator (6) with coherent light to produce a spatial light pattern (8); providing a camera (9) that is attachable to the second machine part (5) and is optically configured to capture a composite image (30) of the spatial light pattern (8); and To enable the camera (9) to capture a first composite image of the spatial light pattern (8) in a first single camera shot using a combination of the camera and the first (7-1) coherent light illumination device and the second (7-2) coherent light illumination device, wherein an area of ​​effective optical distances of a first optical configuration (11A), in which light is transmitted along optical paths from a first illumination device (7-1) via the pattern generator (6) to the camera to generate a first spatial light pattern component (8A) of the spatial light pattern (8), does not overlap with an area of ​​effective optical distances of a second optical configuration (11B),in which light is transmitted along optical paths from the second illumination device (7-2) via the pattern generator (6) to the camera to generate a second spatial light pattern component (8B) of the spatial light pattern (8), and , wherein each of the first (7-1) and second (7-2) illumination devices is configured to illuminate the pattern generator (6) with coherent light of a coherence length greater than a maximum optical path length difference within each of the first (11A) and second (11B) optical configurations. [12] Method for capturing, translating and rotating a first part relative to the translation and rotation of a second part of a computer-controlled machine with at least one movable carrier (3) for changing the position of the first machine part relative to that of the second machine part at a plurality of machine part positions, comprising moving the movable carrier to a plurality of positions, and at each position, performing the method according to claim 17 and recording the data of the captured composite image (30) and associated carrier position data (31, 32) relating to the position of the carrier in a data storage means (10). [13] Method according to claim 12, wherein at each position of the carrier the first (7A) and the second (7B) illumination device are controlled such that they operate alternately to capture images of the first (8A) and the second (8B) spatial light pattern component separately and not simultaneously and only in the respective optical configuration of the first (11A) and the second (11B). [14] Method according to claim 12, wherein composite images (30) are recorded at each position of the carrier using a plurality of cameras (9) configured to record images in different object planes. [15] Method for deriving data for calibrating or improving the relative positioning of parts of a computer-controlled machine, comprising a movable carrier for changing the position of a first machine part relative to that of the second machine part, wherein the method comprises the following Providing a sensor device according to claim 1 in the computer-controlled machine, Moving the carrier to a multitude of carrier positions, such that the position of the first machine part relative to that of the second machine part changes for each of the multitude of positions, and at each carrier position, Recording position data relating to the position of the carrier and operating the sensor to capture and record data of composite images (30) of spatial light patterns (8) composed of at least one first (8A) and one second (8B) spatial light pattern component in each of the first (11A) and second (11B) optical configurations, and Processing recorded data of composite images with reference image data from a reference database, comprehensively linked, separately recorded reference image and position data relating to the first and second spatial light pattern components that are imaged and recorded using the sensor device (1) in a reference machine, and Finding pairs of corresponding composite image data and reference image data, Deriving image translation offset data for each pair of corresponding composite image and reference image data, and Deriving translation and rotation data for the calibration or improvement of the relative positioning of parts of the computer-controlled machine based on light pattern translation offset data relating to the first and second optical configurations.