DE102012217176A1 - Method for aligning a laser sensor to a measured object - Google Patents

Abstract

The invention relates to a method for scaling the position and the alignment of at least one laser distance sensor to a calibration body, each laser distance sensor each having a laser and a sensor, comprising the following chronological steps A) to C): A) Arranging a well-defined calibration body with at least one Geometry precisely defined in regions in a measurement setup comprising the laser distance sensors, the position of the calibration body being precisely defined by the arrangement of the calibration body in the measurement setup, and rough alignment of at least one laser distance sensor to the calibration body; B) Distance measurements of several measuring points or a continuous course on the surface of the calibration body by the laser distance sensor or the laser distance sensors, wherein the calibration body is moved in the measurement setup relative to the laser distance sensor or the laser distance sensors in order to the laser of the laser distance sensor or the lasers of the laser distance sensors the irradiation of the different To enable measuring points or the continuous course for the distance measurements; and C) determining the position and the alignment of the at least one laser distance sensor to the calibration body on the basis of the distance measurements and the known geometry and position of the calibration body in the measurement setup. The invention also relates to a method for measuring the thickness of a body or a coating of a coated body in a measurement setup, with at least one laser distance sensor being used when measuring the thickness of the coating, the position and alignment of which with respect to the calibration body was determined using such a method was previously aligned in the measurement setup with such a method against a calibration body. Finally, the invention also relates to a device for performing such methods.

Description

The invention relates to a method for scaling the position and the orientation of at least one laser distance sensor. The invention also relates to a method for measuring the thickness of a body or the thickness of a coating of a coated body in a measurement setup, wherein at least one laser distance sensor is used in the measurement. Finally, the invention also relates to a device for carrying out such methods.

Laser distance sensors are used, inter alia, when the thickness of a coating is to be measured precisely. In this case, the light reflected from the coating on an object is measured and from this the thickness of the coating is determined.

Such a method is for example from the EP 2 031 347 A1 In the case of measurement, the temperature of the object to be coated is also measured in order to obtain a more accurate estimate of the thickness of a coating in the case of a thickness measurement.

A method for measuring the coating thickness by means of laser triangulation is known from EP 2 312 267 A1 known. The measurement is measured before and during or after coating and can be carried out selectively. A similar procedure comes with the DE 103 13 888 A1 for use. In the method, a distance is determined by a laser triangulation method and compared with a reference value in order to be able to estimate the thickness of a coating.

For all these methods, it is important to precisely set the position of the laser for the measurement in order to allow a reliable determination of the layer thicknesses. An error in the positioning affects the accuracy of the layer thickness measurement and therefore leads to errors in the determination of the layer thickness. The aim is to align the position and the orientation of the laser as closely as possible to the object to be measured.

The object of the invention is therefore to provide a method for positioning a laser of a laser distance sensor to a coated body to be measured, which is as simple to carry out and leads to the most accurate adjustment and positioning of the laser distance sensor to the object to be measured.

Other tasks not explicitly mentioned arise from the overall context of the following description, examples and claims.

These are solved as well as other tasks which are not explicitly mentioned, but which can be readily deduced or deduced from the contexts discussed herein by way of a method having all the features of patent claim 1 and by a method having all the features of claim 16. Advantageous modifications of the method according to the invention according to claim 1 are provided in the dependent claims 2 to 15 under protection. Likewise, a useful modification of the method according to claim 16 is provided in dependent claim 17 under protection. A solution of the objects of the invention is also provided by an apparatus for implementing such a method according to claim 18. The dependent claims 19 and 20 claim appropriate modifications of the device.

• A) Anordnen eines wohldefinierten Eichkörpers mit einer zumindest bereichsweise genau definierten Geometrie in einen Messaufbau umfassend die Laserabstandssensoren, wobei die Lage des Eichkörpers durch das Anordnen des Eichkörpers im Messaufbau genau definiert wird, und Grobausrichtung zumindest eines Laserabstandssensors zum Eichkörper;
• B) Abstandsmessungen mehrerer Messpunkte oder eines kontinuierlichen Verlaufs auf der Oberfläche des Eichkörpers durch den Laserabstandssensor oder die Laserabstandssensoren, wobei der Eichkörper im Messaufbau relativ zu dem Laserabstandssensor oder den Laserabstandssensoren bewegt wird, um dem Laser des Laserabstandssensors oder den Lasern der Laserabstandssensoren die Bestrahlung der verschiedenen Messpunkte oder des kontinuierlichen Verlaufs für die Abstandsmessungen zu ermöglichen; und
• C) Bestimmen der Position und der Ausrichtung des zumindest einen Laserabstandssensors zum Eichkörper anhand der Abstandsmessungen und der bekannten Geometrie und Lage des Eichkörpers im Messaufbau.

Accordingly, the present invention is accomplished by a method of scaling the position and orientation of at least one laser proximity sensor to a calibration body, each laser distance sensor each having a laser and a sensor comprising the following chronological steps A) through C):

• A) arranging a well-defined calibration body with an at least partially precisely defined geometry in a measurement setup comprising the laser distance sensors, wherein the position of the calibration body is precisely defined by arranging the calibration body in the measurement setup, and coarse alignment of at least one laser distance sensor to the calibration body;
• B) distance measurements of a plurality of measurement points or a continuous course on the surface of the calibration body by the laser distance sensor or the laser distance sensors, wherein the calibration body is moved in the measurement setup relative to the laser distance sensor or the laser distance sensors to the laser of the laser distance sensor or the lasers of the laser distance sensors, the irradiation of the allow different measurement points or the continuous course for the distance measurements; and
• C) Determining the position and the orientation of the at least one laser distance sensor to the calibration body based on the distance measurements and the known geometry and position of the calibration body in the measurement setup.

By the method according to the invention, among others, the following advantages can be achieved:
The method is simple to implement and therefore inexpensive to implement. In addition, with the method, a high accuracy of a subsequent measurement can be achieved. It may be sufficient if only the orientation of the laser distance sensor is adjusted.

A scaling of the position and the orientation of at least one laser distance sensor is the same if only the position and the orientation of at least one laser of a laser distance sensor are scaled, if the laser and the sensor of the laser distance sensor are not fixed to one another.

Under a well-defined geometry and storage of the calibration body is understood as high accuracy. Preferably, the dimensions and the mounting of the calibration body can be manufactured to at least 0.5 mm, particularly preferably to at least 0.1 mm, very particularly preferably to at least 0.01 mm. The angles of the surfaces to the axis of rotation and to each other can be made at least to 1 °, preferably to at least 0.1 ° accurate, most preferably to at least 0.01 ° accurate.

It can be inventively provided that the method comprises a step D), D) adjustment of the at least one laser distance sensor based on the thus determined position and orientation of the at least one laser distance sensor to the calibration body, so that a desired position and a desired orientation of the at least one laser distance sensor Calibration body is sought, wherein step D) after step C) takes place.

By performing the adjustment directly after the measurement or between different measurements can be achieved that the evaluation of a subsequent measurement is simplified, without the subsequent measurement would have to be corrected computationally.

A further embodiment of a method according to the invention can provide that the distance measurements are performed on at least five measuring points on the surface of the calibration body by the laser distance sensor or the laser distance sensors are performed.

A higher number of measuring points leads to a smaller error in the subsequent evaluation of the results. At the same time, however, a small number of measuring points accelerate the entire process.

According to a further, particularly preferred embodiment of the invention can be provided that the calibration body is rotatably mounted in the measurement setup and the measurement points are driven by rotating the calibration body in the measurement setup about the axis of rotation or the continuous course is driven by rotating the calibration body in the measurement setup about the axis of rotation , wherein preferably the laser distance sensor or the laser distance sensors is aligned at the rotation axis as a desired orientation or, more preferably, the orientation of the laser distance sensor or the laser distance sensors to the rotation axis with an angle (Γ) of less than 20 °, most preferably at an angle (Γ) less than 5 °.

A rotatable calibration body, in particular a turntable as calibration body, simplifies the entire structure. In addition, the structure can be made much more compact with a rotating calibration body.

It can be provided that the angular velocity (ω) of the calibration body about the axis of rotation when determining the position and orientation of the at least one laser distance sensor to the rotatable calibration body is taken into account mathematically, in particular in the distance measurement of the continuous course.

By this method, there are possibilities for a simple evaluation of the signal periodic by the rotation.

Furthermore, it can be provided that the angle of rotation (.phi.) Of the calibration body is determined, the time (t) preferably being measured at known angular velocity (.omega.) In order to determine the angle of rotation (.phi.) Of the calibration body, with a marker being particularly preferred the calibration body is measured with the at least one laser distance sensor to determine a full revolution.

As a result, an additional direct measurement of the rotation angle (φ) of the calibration body can be avoided.

Most preferably, it can be provided that a turntable is used as the calibration body, wherein preferably the turntable is inclined against the rotation axis, particularly preferably a tilt angle (δ) between 5 ° and 60 °, very particularly preferably a tilt angle (δ) between 15 ° and 30 ° is inclined.

Due to the inclination or tilting of the turntable increases in a periodic measurement of the swept value range of the signal of the distance measurement. This leads to a better evaluable signal and thus to a more accurate scaling of the orientation and optionally also the position of the at least one laser distance sensor relative to the calibration body.

It can be provided that the tilt angle (δ) of the turntable against the axis of rotation in determining the position and the orientation of the at least one laser distance sensor to the turntable is considered mathematically.

By this measure, a further simplification of the calculation of the sought parameters can be achieved. For the scaling of the orientation and the position of a single laser distance sensor, the tilt angle (δ) of the rotary disk relative to the axis of rotation must be known as precisely as possible.

It can also be provided that the laser beam generated by the laser of the at least one laser distance sensor always hits the respectively identical side of the turntable during the distance measurement.

This measure also serves to simplify the arithmetic evaluation for determining the position and orientation of the laser distance sensor.

bestimmt werden oder mit einer Taylorreihenentwicklung dieser Gleichung bestimmt werden, vorzugsweise mit einer Fourier-Analyse einer Taylorreihenentwicklung dieser Gleichung bestimmt werden, wobei l₁ die Messwerte des zumindest einen Laserabstandssensors beim Auftreffen auf die Drehscheibe ist, n der Normalvektor der Drehscheibe, d₁ der Positionsvektor des Schnittpunkts einer Oberfläche der Drehscheibe mit der Drehachse, b₁ der Positionsvektor des virtuellen Schnittpunkts des Laserstrahls mit der zugehörigen x-y-Ebene E₁ durch den Punkt d₁, ĉ₁ der in der z-Richtung auf den Betrag von 1 normierten Richtungsvektor des auf die Drehscheibe einfallenden Laserstrahls von Laser 1 in Richtung steigender Messwerte und l_0,1 der Messwert des Laserabstandssensors, welcher sich beim Vermessen des Punktes b₁ ergeben würde..A particularly preferred embodiment of the invention can provide that the position and orientation of the at least one laser distance sensor to the hub by Parameterfits the equation

be determined or determined by a Taylor series expansion of this equation, preferably determined by a Fourier analysis of a Taylor series evolution of this equation, where l _{1 is} the measurements of the at least one laser distance sensor when hitting the turntable, n is the normal vector of the turntable, d _{1 is} the position vector the point of intersection of a surface of the turntable with the axis of rotation, b ₁ the position vector of the virtual intersection of the laser beam with the associated xy plane E ₁ through the point d ₁ , ĉ _{1 of} the directional vector of the normalized in the z direction direction vector of the turntable incident laser beam from laser 1 in the direction of increasing measured values and l _0.1 the measured value of the laser distance sensor, which would result in measuring the point b ₁ ..

An evaluation of the above formula with the specified means is mathematically feasible and therefore suitable for calculatory evaluation.

It can also be provided that in calculating the data for determining the position and orientation of the at least one laser distance sensor for the calibration body from a periodic distance measurement, the amplitudes of a fundamental wave (F _1,1 ), in particular the amplitudes of a fundamental wave (F _{1, 1} ) and at least the first harmonic (F _2,1 ), wherein preferably the fundamental (F _1,1 ) and / or at least the first harmonic (F _2,1 ) are calculated by a Fourier analysis of the periodic distance measurement , are particularly preferably calculated by a Taylor series development and a Fourier analysis of the periodic distance measurement.

The evaluation of a fundamental wave (F _1,1 ) and at least the first harmonic (F _2,1 ) of the periodic signal results in high accuracy of the result to a simple practicability of the method. Details can be found in the mathematical derivation of the 3 to 5 hereinafter.

It can be provided that in the calculation of the fundamental wave (F _1,1 ) and / or at least the first harmonic (F _2,1 ) is assumed that the amplitudes of the fundamental wave (F _1,1 ) and / or at least the first Harmonic (F _2.1 ) is greater than or equal to zero.

This assumption also leads to a simplification of the arithmetic evaluation of the signals.

in Zylinderkoordinaten zur Bestimmung der Position und der Ausrichtung des zumindest einen Laserabstandssensors mit den Gleichungen

berechnet werden, wobei µ₁ die Phasenlage der Grundwelle von l₁(φ) und η₁ die Phasenlage der 1. Oberwelle von l₁(φ) ist, ĉ_z1 = sign(c_z1) die z-Ausrichtung des Lasers zur Drehscheibe angibt, δ der Verkippungswinkel der Drehscheibe gegen die Drehachse ist und F_1,1 die gemessene Amplitude der Grundwelle und F_2,1 die gemessene Amplitude der ersten Oberwelle ist.In a very particularly preferred embodiment of the method according to the invention, it can be provided that the angles β ₁ and γ ₁ and the amplitudes Ĉ ₁ and B _{1 of} the representation of the vectors

in cylindrical coordinates for determining the position and orientation of the at least one laser distance sensor with the equations

where μ _{1 is} the phase position of the fundamental wave of l ₁ (φ) and η _{1 is} the phase position of the first harmonic of l ₁ (φ), ĉ _z1 = sign (c _z1 ) indicates the z-orientation of the laser to the turntable , δ is the tilt angle of the turntable against the axis of rotation and F _{1,1 is} the measured amplitude of the fundamental and F _{2,1 is} the measured amplitude of the first harmonic.

These formulas, with high accuracy, greatly simplify the formulas for evaluating a signal from a rotating tilted or tilted turntable.

Furthermore, provision can be made for the distance measurements to be carried out using a laser triangulation method and / or for the at least one laser distance sensor to be calibrated in the course of alignment on the basis of the measured data and / or the variables calculated therefrom.

The calibration is particularly preferably carried out by the calculation of the additive proportion l _{0.1 of} the respective measurement signal by l _0.1 = F _0.1 - F _2.1 · cos (γ ₁ - β ₁ ).

Laser triangulation methods are simple and inexpensive to implement and particularly suitable for the implementation of scaling methods according to the invention.

A further development of the invention can provide that the relative position and orientation of at least two laser distance sensors are determined relative to one another, and uncertainties are compensated for by errors in the assessment of the position and geometry of the calibration body.

The relative determination can compensate for errors or uncertainties in the geometry and the bearing of the calibration body.

The objects of the invention are also achieved by a method for measuring the thickness of a body or a coating of a coated body in a measurement setup, wherein at least one laser distance sensor whose position and orientation to the calibration body has been determined by such a method is used in the measurement of the thickness or which has previously been aligned in the measurement setup with such a method against a calibration body.

The advantages of scaling are particularly significant in measuring the thickness of a body or coating of a coated body.

• E) Entfernen des Eichkörpers aus dem Messaufbau;
• F) Einsetzen des beschichteten Körpers in eine Lagerung, die eine bekannte Position und Orientierung zu dem zuvor gelagerten Eichkörper im Messaufbau hat; und
• G) Messen der Dicke eines Körpers oder dessen Beschichtung mit Hilfe des zumindest einen ausgerichteten und positionierten Laserabstandssensors und/oder Messen der Dicke des einen Körpers oder dessen Beschichtung, wobei die Position und die Ausrichtung des zumindest einen Laserabstandssensors rechnerisch berücksichtigt wird.

Such methods may preferably also include the following chronological steps:

• E) removing the calibration body from the measurement setup;
• F) inserting the coated body into a bearing having a known position and orientation to the previously stored calibration body in the measurement setup; and
• G) measuring the thickness of a body or its coating by means of the at least one aligned and positioned laser distance sensor and / or measuring the thickness of the one body or its coating, wherein the position and orientation of the at least one laser distance sensor is taken into account mathematically.

As indicated by the alphabetical order of the letters, said steps are carried out in chronological order and according to steps A) to G) of the alignment methods according to the invention.

Further, according to the invention, a step H) may be provided after step G), in which a determination of the thickness of the coating is carried out from the measurement of the thickness of the coated body.

The objects of the invention are also achieved by an apparatus for carrying out such a method, in which the apparatus comprises at least one laser distance sensor and a bearing for a body to be measured, each laser distance sensor having a laser and a sensor, the bearing for supporting a calibration body with at least in areas defined well-defined surface is designed and the calibration body is defined in the device movable.

It can be provided that the calibration body is rotatably mounted in the device or is storable and the calibration body is rotatable about a defined angle (φ) about an axis of rotation and / or with at least one defined angular velocity (ω) is rotatable.

It can be provided in turn that the calibration body is a disc which is inclined against the axis of rotation, preferably tilted by a Verkippungswinkel (δ) between 5 ° and 60 °, more preferably by a Verkippungswinkel (δ) between 15 ° and 30 ° is inclined, most preferably inclined by a tilt angle (δ) between 20 ° to 25 °.

The invention is based on the surprising finding that it is possible to scale the position and orientation of a laser distance sensor or a laser of such a laser distance sensor so accurately by measuring on the surface of a defined calibration body that in a subsequent measurement of a coated body with unknown layer thickness Coating a particularly high accuracy can be achieved, or an improvement in the accuracy can be achieved. The method is relatively simple to perform and easy to implement with the computing power of modern computing systems.

The aim of a measurement setup according to the invention and an evaluation procedure or a method according to the invention is to determine the position and tilt of one or more laser distance sensors relative to a rotation axis defined by the measurement setup. The process is very robust because it does not use the absolute value of the laser distance sensor. In addition, the test setup is characterized by a low height.

• a) einen oder mehrerer Laserabstandssensoren parallel zu einer durch den Messaufbau definierten Drehachse auszurichten,
• b) zwei oder mehrere Lasersensoren zueinander parallel auszurichten, und/oder
• c) die Laserstrahlen von zwei gegenläufigen Laserabstandssensoren exakt aufeinander zu legen.

The position parameters determined in this way can be used in particular for this purpose

• a) align one or more laser distance sensors parallel to a rotation axis defined by the measurement setup,
• b) align two or more laser sensors parallel to each other, and / or
• c) to place the laser beams of two counter-rotating laser distance sensors exactly on each other.

Exemplary embodiments of the invention and calculations relating to the invention are explained below with reference to five schematically illustrated figures, without, however, limiting the invention. Showing:

1 a schematic side view of a structure for implementing a method according to the invention in a desired position;

2 a schematic side view of a structure for implementing a method according to the invention with coarse alignment at the beginning of the process;

3 : a schematic perspective view to illustrate the angular relationships in a structure for implementing a method according to the invention in an initial situation;

4 Two schematic side views of a turntable according to the representation in 3 ; and

5 : a perspective diagram to illustrate the geometric relationships.

1 shows a schematic side view of a measurement setup for implementing a method according to the invention in a desired position. The measurement setup includes a laser distance sensor 2 who has a laser 8th and a sensor 10 having. The laser 8th and the sensor 10 are arranged at a fixed angle to each other. Above the laser distance sensor 2 becomes a disk as a calibration body 12 arranged and rotatably supported about a rotation axis z. The axis of rotation z does not have to be a material axis, as suggested by the drawing, for example if the calibration body 12 is held in a rotatable frame.

The laser beam from the laser 8th hits the calibration body 12 in the illustration on the underside. Just as well, the laser beam could also on the top of the calibration body 12 to meet. As sensors 10 For example, conventional CCD chips with an upstream lens can be used. Such sensors 10 for measuring the reflected laser light are known from laser triangulation method for determining the layer thickness of a coated body.

In the in 1 The view shown is the laser 8th in a desired orientation to the calibration body 12 aligned, namely parallel to the axis of rotation z of the calibration body 12 , If the laser beam as a vector in the coordinate system of the calibration body 12 is understood, this is parallel to the z-axis. With the method according to the invention, the in 1 shown alignment and positioning of the laser distance sensor 2 to the calibration body 12 be reached or a correction formula can be determined, with which the measurement results of the laser distance sensor 2 can be converted so that they the measurement result of a correctly aligned laser distance sensor 2 (as in 1 shown) would correspond.

First, the laser distance sensor 2 only roughly aligned or misaligned in the measurement setup. This arrangement is in 2 shown as a schematic side view. The laser distance sensor 2 is not exactly parallel to the axis of rotation z of the calibration body 12 arranged but tilted against the z-axis. The aim of the method is to use the laser distance sensor 2 so against the calibration body 12 to align that the arrangement in the 1 shown state comes as close as possible. Alternatively, the correction formula may also be determined to match that with the tilted laser distance sensor 2 to correct recorded measurement data in such a way that it matches the measurement data of a well-aligned laser distance sensor 2 (in 1 shown).

This is the calibration body 12 introduced into the measuring structure and rotatably mounted there. With the laser distance sensor 2 be several measuring points on the lower surface of the calibration body 12 added. This is the calibration body 12 shot in construction. Not only discrete measuring points on the surface of the calibration body are preferred 12 but it is a continuous course of the distances of the laser distance sensor 2 from the surface of the rotating calibration body 12 added. At a known angular velocity ω and as accurately known geometry of the calibration body 12 can from the periodic signal of the laser distance sensor 2 Information can be obtained, the precise conclusions about the arrangement and orientation of the laser 8th and thereby the laser distance sensor 2 to the calibration body 12 allow. The information thus obtained can be used to adjust the laser distance sensor 2 to be used in the 1 to achieve the desired state or to come as close as possible. Alternatively, the information thus obtained may be used to calculate the correction formula to match that with the tilted laser distance sensor 2 to correct recorded measurement data in such a way that it matches the measurement data of a well-aligned laser distance sensor 2 (in 1 shown).

In a preferred embodiment, a turntable 12 as calibration body 12 rotatably mounted in the test setup. The turntable 12 is inclined from the rotation axis z by an angle δ. The turntable 12 gets into the laser beam of the laser distance sensor 2 and the measured values of the distance measurement of the laser 8th to the point of impact of the laser beam on the turntable 12 detected during their rotation.

Optionally, the absolute angle (or at least its zero crossing) of the turntable 12 measured on the axis of rotation z.

The measuring signal causes tilting and positioning of the laser 8th and thus the laser distance sensor 2 to the turntable 12 determined mathematically.

3 shows a schematic perspective view to illustrate the angular relationships in a structure for implementing a method according to the invention in an initial situation with a coarse adjusted laser 28 a laser distance sensor. In a real design, the laser beams of the laser 28 of course on the turntable 32 to meet. The displacement of the laser 28 in the xy-plane, only the clearer representation of the angular relationships is used here.

For the derivation of the geometric equations and the description of the setting algorithm, the definition of a coordinate system and of variables is necessary.

The z-axis of the Cartesian coordinate system becomes the axis of rotation of a turntable 32 placed. The turntable 32 is used as calibration body in the test setup. The x- and y-axis is not determined geometrically, but should be based on the adjustment possibilities of the laser sensors. The laser 28 radiates (in this representation from below) onto the turntable 32 ,

The position and orientation of the laser sensor are determined by the direction vector ĉ _{1 of} the laser beam and the puncture point b _{1 of} the laser 28 determined by a plane E ₁ , wherein the plane E _{1 is} parallel to the xy plane and the axis of rotation perpendicularly intersects at point d ₁ , in which also the laser 28 facing side of the turntable 32 the axis of rotation, ie the z-axis, cuts.

4 shows two schematic side views of the hub 32 according to the illustration 3 in order to be able to clearly discuss the mathematical derivation of a solution according to the invention of the problem.

Within the coordinate system is the location of the turntable 32 determined by the respective relevant intercept on the z-axis (d _z1 or d _z2 ) and the normal vector n. Because of the choice of b ₁ , b _z1 = d _z1 . The normal vector n of the turntable 32 is tilted or inclined from the z-axis by the angle δ, with 0 <δ <π / 2, so that also the angle between the surface of the turntable 32 and the x / y plane is δ. The current rotation angle φ of the turntable 32 is the angle between the x-axis and the negative gradient of the turntable projected into the x / y plane 32 the surface with base in the axis of rotation z. After this

parametrisiert.Definition is the normal vector by

parameterized.

5 shows a perspective diagram to illustrate the geometric relationships. The vectors of a laser beam of a laser (for example the laser 28 to 3 ) and the vectors and angles used for the calculation are shown in relation to the coordinate system and the laser beam. For a second laser or other lasers, analogous diagrams result, which in the following lead to analogous considerations.

For the position b ₁ , the following Cartesian coordinates or cylindrical coordinates are used:

dessen z-Komponente normiert ist. Diese Vektoren sind wie folgt parametrisiert:

The direction of the laser is described by two equivalent vectors: the unit vector c ₁ pointing in the direction of the first laser beam, in the direction of increasing measured values, and

whose z-component is normalized. These vectors are parameterized as follows:

Der Winkel zwischen Laserstrahl und Parallelen zur Drehachse beträgt dann Γ₁ = arctan(Ĉ₁). Then ĉ _z1 = c _z1 / | c _z1 | = sign (c _z1 ) and

The angle between the laser beam and parallels to the axis of rotation is then Γ ₁ = arctan (Ĉ ₁ ).

From the measurement, the parameters β ₁ , B ₁ , γ ₁ , Ĉ ₁ , c _{z1 are} determined at the end, from which all representations of b ₁ , ĉ ₁ , and thus the position and tilt, of the first laser result.

The following is the geometry and measurement equation derived:
The points p ₁ on the laser beam of the first laser are parameterized as follows by the respectively associated measured value l ₁ : p ₁ (l ₁ ) = b ₁ + (l ₁ -l _0,1 ) · c ₁ , where l _{0.1 is} the measured value at the point p ₁ = b ₁ .

In addition, all points on the side of the turntable facing the first laser satisfy the equation n ∘ (p ₁ -d ₁ ) = 0, where here the sign "∘" denotes the scalar product.

At the point of intersection between the beam of the laser and the turntable both equations are satisfied and one can eliminate the variable p ₁ and obtains the following condition for the measured value l ₁ at the point of intersection: n ∘ (b ₁ + (l ₁ -l _0,1 ) · c ₁ -d ₁ ) = 0

If we solve the equation for l ₁ , we get

in die obige Gleichung für l₁ einzusetzen. Man erhält

In the following, a Taylor series development and a Fourier analysis of the measurement signal are carried out in order to obtain easily accessible measurement quantities:
To prepare the Taylor development of the measurement signal of ₁ , the relationship becomes

into the above equation for I ₁ . You get

This equation can already be used according to the invention to calculate the position and orientation of the lasers with respect to one another by means of the distance measurements and the known ones. For this purpose, the equation can be solved mathematically using parameter fits. However, further mathematical simplifications lead to a preferred embodiment of the invention with much simpler calculation.

For this purpose, the definitions of the vectors b ₁ , d ₁ , ĉ ₁ and n are used, taking advantage of the fact that d _z1 = b _z1 . The result is

Now you extend counter and denominator with ĉ _z1 / cos (δ) and use that ĉ 2 / z1 = 1 and the addition theorem cos (β ₁ ) cos (φ) + sin (β ₁ ) sin (φ) = cos (φ - β ₁ )

In the following it is assumed for the Taylor series development that the first laser 28 and the rotation axis z have already been coarsely aligned, that is, Ĉ ₁ << cot (δ), for example, Ĉ ₁ << 1 at δ ≦ π / 4.

Then the amount of ε: = ĉ _z1 Ĉ ₁ tan (δ) · cos (φ - γ ₁ ) in the denominator of l ₁ for every angle φ very much smaller than 1 and a Taylor development 1 / ε + 1 = 1 - ε + ε ² - ε ³ + O (Ĉ ₁ ⁴ ) = (1 - ε) · (1 + O (Ĉ ₁ ² )) of the denominator from ₁ to ε justified.

und nach Auflösen der Produktterme der Cosinus-Funktionen

With this Taylor development arises

and after resolving the product terms of the cosine functions

wobei die Fourier-Koeffizienten F_0,1, F_1,1 beziehungsweise F_2,1 bis auf Restterme der Ordnung O(Ĉ₁ ³), O(Ĉ₁ ²) beziehungsweise O(C^ˆ31) stimmen. From this representation the Fourier evolution of l ₁ (φ) in the form can be deduced l ₁ (φ) = F _0,1 + F _1,1 cos (φ - μ ₁ ) + F _2,1 cos (2φ - η ₁ ) + ... read off with F _1,1 ≥ 0, F _2,1 ≥ 0. To obtain always positive amplitudes F _1,1 ≥ 0, regardless of whether the laser beam is the turntable 32 On the top side or from the bottom side, the sign of the prefactor, ie - ĉ _z1 , may have to be expressed by an angle shifted by π in the argument of the cos term. That's how you get

wherein the Fourier coefficients F _0.1, F _1.1 and F _2.1 to residual terms of order O (C ₁ -C ^3), O (C ₁ ²⁾ or O ^(C 31) agree.

With this preliminary work can now be with knowledge of the tilt angle δ of the turntable 32 , the z-orientation of the laser 28 , that is, ĉ _z1 = sign (c _z1 ), and the first terms of the Fourier series l ₁ (φ) = F _0,1 + F _1,1 cos (φ - μ ₁ ) + F _2,1 cos (2φ - η ₁ ) + ... solve the five (nonlinear) equations for the five unknowns β ₁ , γ ₁ , Ĉ ₁ , B ₁ , l _0,1 with the following result:

From the first four sizes can easily be used for the determination of physical adjustment parameters, for example ĉ _x1 = Ĉ ₁ · cos (γ ₁ ), ĉ _y1 = Ĉ ₁ * sin (γ _1), b _x1 = B ₁ · cos (β ₁ ), b _y1 = B ₁ · sin (β ₁ ), which are necessary when using linear tables and tilting tables in the x and y direction.

On the tilt angle δ of the turntable 32 may be from the storage of the turntable 32 closed, which is defined by the measurement setup. The z-orientation of the laser 28 determines if the turntable 32 is irradiated from above or below. It should be noted that the constant term of the Fourier series, ie F _0,1 , is not required for this calculation step and thus the measured value may also be offset.

With knowledge of all five variables, each point p ₁ on the laser beam of the first laser (in the measuring range) can be uniquely assigned to the measured value l ₁ by p ₁ (l ₁ ) = b ₁ + (l ₁ -l _0.1 ) · c ₁ , In particular, the zero point p ₁ (0) = b ₁ - l _0.1 · c ₁ determine in space. For the zero point calibration of the laser, in turn, the offset in the measured value can be determined as the difference between the current measured value and the desired measured value, and the offset can then be taken into account in the evaluation of the later measured values.

In practice, the tilt angle δ is due to the structure of the turntable 32 set and known. With a parallel to the z-axis alignment of the laser 28 not even the exact value is necessary: The angle δ scales the amplitude value of the normalized tilt Ĉ ₁ and the derived values ĉ _x1 , ĉ _y1 , C ₁ , c _x1 , c _y1 only. For the parallel alignment of the laser with the z-axis 28 one seeks zeros of such derived quantities which are independent of the scaling effect of δ.

• 1) Das Messsignal wird an vorher definierten, diskreten Winkelpositionen (Ortsdiskret auf der Drehscheibe 32) gemessen und die Parameter von l₁(φ), zum Beispiel durch eine diskrete Fourier-Transformation, bestimmt. Erfindungsgemäß werden kontinuierliche Messungen wegen der einfacheren Handhabung bevorzugt.
• 2) Statt des winkelabhängigen Messsignals l₁(φ) wird das Zeitsignal l₁(t) und der dazu passende Winkel φ(t) gemessen und daraus l₁(φ) und seine Parameter bestimmt.
• 3) Bei möglicherweise unbekannter, aber konstanter Drehgeschwindigkeit ω der Drehscheibe 32 wird ein Zeitsignal l₁(t) gemessen und die Zeitpunkte, t₀ und t₁, zweier aufeinanderfolgender Nulldurchgänge φ(t₁) = φ(t₀) = 0. Dann kann mit der Winkelgeschwindigkeit
  
  das Winkelsignal
  
  rekonstruiert werden. Zusammen mit dem Zeitsignal l₁(t) können wiederum l₁(φ) und seine Parameter bestimmt werden. Eine konstante Winkelgeschwindigkeit ω führt also zu einer Vereinfachung der Berechnung der Parameter und ist daher erfindungsgemäß besonders bevorzugt.
• 4) Es ist auch möglich, ohne direkte Winkelmessung auszukommen. Angenommen der Winkel β₁ zwischen dem Laser 28 und der Drehscheibe 32 ist, zum Beispiel aufgrund eines vorgefertigten Messaufsatzes, näherungsweise bekannt. Somit ist auch μ₁ bekannt. Es wird ein Zeitsignal l₁(t) bei einer konstanter Drehgeschwindigkeit ω der Drehscheibe 32 aufgenommen. Wenn dann noch der eine Laser 8, 28 schon recht gut ausgerichtet ist, das heißt, wenn Ĉ₁ << cot(δ) gilt, so dominiert die Grundwelle die Oberwelle, das heißt F _1,1>> 2·F_2,1, und es können sehr einfach aufeinanderfolgende Zeitpunkte t_m0 und t_m1 gefunden werden, in dem das Signal das Maximum annimmt. Dann ist
  
  Mit der Kenntnis der Drehgeschwindigkeit ω können die Fourier-Koeffizienten F_0,1, F_1,1, F_2,1 aus dem Zeitsignal l₁(t) bestimmt werden. Um die fehlende Phasenlage η₁ zu erhalten, bestimmt man zuerst Zeitpunkte t_μ1 und t_η1 zu denen die Maxima der Grundwelle und der Oberwelle zu erwarten sind, für die also μ₁ = ω·t_μ1 und η₁ = 2ω·t_η1 gilt. Dann ist
  
  und somit
  
  Dann sind alle Parameter von l₁(φ) für die Auswertung bekannt.

The Fourier coefficients F _0,1 , F _1,1 , F _2,1 and the phases μ ₁ , η ₁ of l ₁ (φ) can be obtained in practice in various ways, as the following cases show:

• 1) The measurement signal is at previously defined, discrete angular positions (discrete location on the turntable 32 ) and the parameters of l ₁ (φ) are determined, for example by a discrete Fourier transform. According to the invention, continuous measurements are preferred for ease of handling.
• 2) Instead of the angle-dependent measurement signal l ₁ (φ), the time signal l ₁ (t) and the matching angle φ (t) is measured and from this l ₁ (φ) and its parameters are determined.
• 3) At possibly unknown, but constant rotational speed ω of the turntable 32 is a time signal l ₁ (t) measured and the times, t ₀ and t ₁ , two consecutive zero crossings φ (t ₁ ) = φ (t ₀ ) = 0. Then can with the angular velocity
  
  the angle signal
  
  be reconstructed. In turn, l ₁ (φ) and its parameters can be determined together with the time signal l ₁ (t). A constant angular velocity ω thus leads to a simplification of the calculation of the parameters and is therefore particularly preferred according to the invention.
• 4) It is also possible to do without direct angle measurement. Suppose the angle β ₁ between the laser 28 and the turntable 32 is approximately known, for example due to a prefabricated measuring attachment. Thus μ ₁ is also known. There is a time signal l ₁ (t) at a constant rotational speed ω of the turntable 32 added. If then the one laser 8th . 28 is already quite well aligned, that is, if Ĉ ₁ << cot (δ) holds, then the fundamental wave dominates the harmonic, that is F _1,1 >> 2 · F _2,1 , and it can very simply successive times t _m0 and t _{m1 are} found, in which the signal assumes the maximum. Then
  
  With the knowledge of the rotational speed ω, the Fourier coefficients F _0,1 , F _1,1 , F _{2,1 can be determined} from the time signal l ₁ (t). In order to obtain the missing phase position η ₁ , one first determines times t _μ1 and t _η1 at which the maxima of the fundamental wave and the harmonic wave are to be expected, for which μ ₁ = ω · t _μ1 and η ₁ = 2ω · t _η1 , Then
  
  and thus
  
  Then all the parameters of l ₁ (φ) are known for the evaluation.

For an estimation of the setting accuracy, a construction with the following parameters is considered below by way of example: δ = π / 6 (= 30 °) ⇒ tan (δ) = 0.58; F _1,1 = 2.5mm; ΔF _1,1 = 1 μm; ΔF _2,1 = 1 μm.

With respect to F _1,1 , this means that at approximately parallel to the axis of rotation of the turntable 12 . 32 aligned laser 8th . 28 the amplitude of the then approximately sinusoidal distance measurements is 2.5 mm and the Fourier coefficients F _1,1 , F _{2,1 were determined} with an uncertainty of 1 μm.

eine Einstellgenauigkeit von

It applies to the normalized tilt

an adjustment accuracy of

The uncertainty in the angle Γ ₁ = arctan (Ĉ ₁ ) between a laser 8th . 28 and a parallel to the rotation axis z is then at these small values of Ĉ ₁ ΔΓ ₁ = 1 / (1 + Ĉ ₁ ² ) · ΔĈ ₁ = 1.3 mrad (= 0.079 °).

und damit eine Einstellungenauigkeit von ΔB₁ ≈ cot(δ)·ΔF_1,1 = 1,72µm. For the distance B _{1 of} the laser point from the rotation axis z to z height d _z1 applies

and thus an inaccuracy of ΔB ₁ ≈ cot (δ) · ΔF _1,1 = 1.72μm.

In the following, the effects on the uncertainty of a thickness measurement are shown.

The setting accuracy of the laser 8th . 28 directly determines the uncertainty of a thickness measurement.

For an estimation we use the above numerical values.

The uncertainty Δd of the measured value in determining the thickness of a plate tilted by a maximum of δ '= 5 ° in a measuring gap with a positioning accuracy in the z-axis direction of h = 2.5 mm by the two setting errors ΔĈ ₁ and ΔB _{1 of} the laser 8th . 28 is then

A second laser (not shown) could provide an analog contribution to refine the measurement. In this case, an alignment of this second laser to the laser 8th . 28 be done to then use both to determine the thickness of the hub and / or their coating.

• 1) Bei der Einstellung von Position und Verkippung der Sensoren 10 ist ein möglichst großer Winkel δ zu wählen und der volle Messbereich möglichst auszunutzen, damit F_1,1 möglichst groß ausfallen kann. Dieser ist jedoch durch die realen Abmessungen des Messaufbaus, wie beispielsweise der Abmessungen der Laserabstandssensoren 2, gegebenenfalls die Dicke der Drehscheibe und der Drehachse oder des Durchmessers des Laserstrahls beschränkt. Für reale Aufbauten mit handelsüblichen Laserabstandssensoren 2 wird ein Winkel δ zwischen 15° und 35° besonders bevorzugt, da er mit diesen Bauteilen gut realisierbar ist.
• 2) Die Auflösung der Laserabstandssensoren 2 sollte möglichst hoch sein, damit ΔF_1,1 und ΔF_2,1 möglichst klein sind. Die Auflösung der Laserabstandssensoren 2 kann beispielsweise durch ein Messrauschen auf 1 µm begrenzt sein.
• 3) Bei der eigentlichen Vermessung des zu messenden Objekts sollte dieses möglichst wenig verkippt sein, das heißt der Winkel δ' möglichst klein sein, und in Richtung der z-Achse möglichst ruhig liegen, das heißt h möglichst gering sein. Eine Neigung des zu messenden Objekts von 0° kann dabei bevorzugt vorgesehen sein.

In order to keep the uncertainty low, the following points should be noted:

• 1) When adjusting the position and tilt of the sensors 10 If possible, choose the largest possible angle δ and use the full measuring range as far as possible so that F _1,1 can be as large as possible. However, this is due to the real dimensions of the measurement setup, such as the dimensions of the laser distance sensors 2 , Where appropriate, the thickness of the hub and the axis of rotation or the diameter of the laser beam limited. For real structures with standard laser distance sensors 2 If an angle δ between 15 ° and 35 ° is particularly preferred because it is well feasible with these components.
• 2) The resolution of the laser distance sensors 2 should be as high as possible so that ΔF _1,1 and ΔF _{2,1 are} as small as possible. The resolution of the laser distance sensors 2 may for example be limited by a measurement noise to 1 micron.
• 3) In the actual measurement of the object to be measured this should be as little as possible tilted, that is, the angle δ 'be as small as possible, and lie as quiet as possible in the direction of the z-axis, that is h should be as low as possible. An inclination of the object to be measured of 0 ° can preferably be provided.

Two exemplary setting algorithms for methods according to the invention are presented below.

When constructing a suitable measuring device, the restrictions for its use must be taken into account. In particular, it must be ensured that the measuring range of the laser distance sensors 2 During the measurement both adhered to, and also very well used.

The built-up measuring device is in the beam path of the laser 8th . 28 used.

• 1) Achsen von Laser 8, 28 und Drehachse z grob parallel ausrichten (⇒ Ĉ₁ << cot(δ));
• 2) Signal l₁ messen;
• 3) Fourier-Koeffizienten F_1,1, F_2,1 und die Phasen μ₁, η₁ von l₁(φ) bestimmen;
• 4) Position und Verkippung des Lasers 8, 28 durch β₁, γ₁, Ĉ₁, B₁ bestimmen;
• 5) Verstellparameter von Laser 8, 28 bestimmen;
• 6) Verkippung nachjustieren, bis sie gut (in der Regel nahe Null gegen die z-Achse) ist; und
• 7) Position nachjustieren, bis sie gut ist (bis die Position der gewünschten Position entspricht).

To a laser 8th . 28 to align with respect to the axis of rotation z, proceed as follows:

• 1) axes of laser 8th . 28 and align the axis of rotation z roughly parallel (⇒ Ĉ ₁ << cot (δ));
• 2) Measure signal l ₁ ;
• 3) determine Fourier coefficients F _1,1 , F _2,1 and the phases μ ₁ , η ₁ of l ₁ (φ);
• 4) Position and tilt of the laser 8th . 28 by β ₁ , γ ₁ , Ĉ ₁ , B ₁ determine;
• 5) Adjustment parameters of laser 8th . 28 determine;
• 6) readjust tilt until it is good (usually close to zero against the z axis); and
• 7) Adjust the position until it is good (until the position corresponds to the desired position).

The features of the invention disclosed in the foregoing description, as well as the claims, figures and embodiments may be essential both individually and in any combination for the realization of the invention in its various embodiments.

LIST OF REFERENCE NUMBERS

2

 Laser distance sensor

8, 28

 laser

10

 sensor

12, 32

 calibration body

Geometric variables δ Tilt angle between turntable ( 12 . 32 ) and axis of rotation (z) φ Angle between projection of the gradient of the turntable ( 12 . 32 ) in xy plane and x axis n Normal vector of the turntable ( 12 . 32 ) (with positive z-component) d ₁ Position vector of the point of intersection of the surface of the turntable facing the first laser ( 12 . 32 ) with the rotation axis (z) d _z1 z-component of the position vector d ₁ E ₁ virtual plane perpendicular to the axis of rotation at z-height of d _z1 b ₁ Position vector of the virtual intersection of the laser beam ( 8th . 28 ) with level E ₁ b _x1 , b _y1 , b _z1 x, y, z component of the position vector b ₁ B ₁ Distance of the position vector b ₁ of rotation axis (z) β ₁ Angle between projection of the position vector b ₁ in xy-plane and x-axis (= direction of the virtual intersection b ₁ ) c ₁ Direction vector of the first laser beam ( 8th . 28 ) in the direction of increasing measured values c _x1 , c _y1 , c _z1 x, y, z component of the direction vector c ₁ ĉ ₁ on | c _z1 | normalized direction vector c ₁ , ie ĉ ₁ = 1 / | c _z1 | · c ₁ ĉ _x1 , ĉ _y1 , ĉ _z1 x, y, z component of the normalized direction vector ĉ ₁ with ĉ _z1 = sign (c _z1 ) Ĉ ₁ Amplitude of normalized tilt ĉ ₁ projected in xy plane γ ₁ Angle between projection of the direction vector c ₁ in xy-plane and x-axis (= direction of tilting) Γ ₁ = arctane (Ĉ ₁ ) Angle between the first laser beam ( 8th . 28 ) and parallel to the axis of rotation (z) x x-axis perpendicular to the z-axis of the Cartesian coordinate system y y-axis perpendicular to the z-axis and x-axis of the Cartesian coordinate system z Rotational axis of the calibration body and z-axis of the Cartesian coordinate system Measured values and parameters ₁ Measured value of the first laser sensor when hitting the turntable ( 12 . 32 ) _0.1 Measured value of the first laser sensor when measuring the point b ₁ F _0.1 constant term in Fourier evolution of l ₁ (φ) F _1,1 Amplitude of the fundamental wave of l ₁ (φ) F _2.1 Amplitude of the 1st harmonic of l ₁ (φ) μ ₁ Phase position of the fundamental wave of l ₁ (φ) η ₁ Phase angle of the 1st harmonic of l ₁ (φ) ω (constant) angular velocity dφ / dt of the turntable ( 12 . 32 )

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• EP 2031347 A1 [0003]
• EP 2312267 A1 [0004]
• DE 10313888 A1 [0004]

Claims (20)

Method for scaling the position and the orientation of at least one laser distance sensor ( 2 ) to a calibration body ( 12 . 32 ), each laser distance sensor ( 2 ) each have a laser ( 8th . 28 ) and a sensor ( 10 comprising the following chronological steps A) to C): A) arranging a well-defined calibration body ( 12 . 32 ) with an at least partially exactly defined geometry in a measurement setup comprising the laser distance sensors ( 2 ), wherein the position of the calibration body ( 12 . 32 ) by arranging the calibration body ( 12 . 32 ) is precisely defined in the measurement setup, and coarse alignment of at least one laser distance sensor ( 2 ) to the calibration body ( 12 . 32 ); B) distance measurements of several measuring points or of a continuous course on the surface of the calibration body ( 12 . 32 ) by the laser distance sensor ( 2 ) or the laser distance sensors ( 2 ), wherein the calibration body ( 12 . 32 ) in the measurement setup relative to the laser distance sensor ( 2 ) or the laser distance sensors ( 2 ) is moved to the laser ( 8th . 28 ) of the laser distance sensor ( 2 ) or the lasers ( 8th . 28 ) of the laser distance sensors ( 2 ) to allow the irradiation of the different measuring points or of the continuous course for the distance measurements; and C) determining the position and the orientation of the at least one laser distance sensor ( 2 ) to the calibration body ( 12 . 32 ) based on the distance measurements and the known geometry and position of the calibration body ( 12 . 32 ) in the test setup. Method according to claim 1 comprising step D), D) adjusting the at least one laser distance sensor ( 2 ) based on the thus determined position and orientation of the at least one laser distance sensor ( 2 ) to the calibration body ( 12 . 32 ), so that a desired position and a desired orientation of the at least one laser distance sensor ( 2 ) to the calibration body ( 12 . 32 ), wherein step D) takes place after step C). A method according to claim 1 or 2, characterized in that the distance measurements at at least five measuring points on the surface of the calibration body ( 12 . 32 ) by the laser distance sensor ( 2 ) or the laser distance sensors ( 2 ) be performed. Method according to one of the preceding claims, characterized in that the calibration body ( 12 . 32 ) is rotatably mounted in the measuring structure and the measuring points by turning the calibration body ( 12 . 32 ) in the measurement setup about the axis of rotation (z) are controlled or the continuous course by turning the calibration body ( 12 . 32 ) is traveled in the measurement setup about the axis of rotation (z), wherein preferably the laser distance sensor ( 2 ) or the laser distance sensors ( 2 ) is aligned at the rotational axis (z) as a desired orientation or, particularly preferably, the orientation of the laser distance sensor ( 2 ) or the laser distance sensors ( 2 ) to the axis of rotation (z) with an angle (Γ) of less than 20 °, very particularly preferably with an angle (Γ) of less than 5 °. Method according to Claim 4, characterized in that the angular velocity (ω) of the calibration body ( 12 . 32 ) about the axis of rotation (z) in determining the position and the orientation of the at least one laser distance sensor ( 2 ) to the rotatable calibration body ( 12 . 32 ) is mathematically taken into account, especially in the distance measurement of the continuous course. Method according to one of claims 4 or 5, characterized in that the angle of rotation (φ) of the calibration body ( 12 . 32 ), wherein preferably the time (t) at a known angular velocity (ω) is measured to the rotation angle (φ) of the calibration body ( 12 . 32 ), wherein particularly preferably a marker on the calibration body ( 12 . 32 ) with the at least one laser distance sensor ( 2 ) is measured to determine a full revolution. Method according to one of claims 4 to 6, characterized in that as calibration body ( 12 . 32 ) a turntable is used, wherein preferably the turntable is inclined relative to the rotation axis (z), more preferably tilted by a tilt angle (δ) between 5 ° and 60 °, most preferably by a tilt angle (δ) between 15 ° and 30 ° is. A method according to claim 7, characterized in that the tilt angle (δ) of the turntable against the axis of rotation (z) in determining the position and orientation of the at least one laser distance sensor ( 2 ) is considered mathematically to the hub. Method according to claim 7 or 8, characterized in that that of the laser ( 8th . 28 ) of the at least one laser distance sensor ( 2 ) laser beam always hits the same side of the turntable during the distance measurement. Method according to one of claims 7 to 9, characterized in that the position and the orientation of the at least one laser distance sensor ( 2 ) to the turntable through parameter fits of the equation

be determined or are determined by a Taylor series expansion of this equation, preferably determined by a Fourier analysis of a Taylor series development of this equation, where l _{1 is} the measured value of the one laser distance sensor when hitting the turntable ( 12 . 32 ), n is the normal vector of the turntable ( 12 . 32 ), d _{1 is} the position vector of the intersection of the laser-facing surface of the turntable with the axis of rotation, b _{1 of} the position vectors of the virtual intersection of the first laser beam with the associated xy planes E ₁ through the point d ₁ , ĉ ₁ of the z in the z Direction to the amount of 1 normalized direction vector of the turntable ( 12 . 32 ) incident laser beam from laser ( 8th . 28 ) in the direction of increasing measured values and l _0.1 the measured value of the first laser distance sensor, which would result when measuring the point b ₁ . Method according to one of the preceding claims, characterized in that in the calculation of the data for the determination of the position and the orientation of the at least one laser distance sensor ( 2 ) to the calibration body ( 12 . 32 ) from a periodic distance measurement, the amplitudes of a fundamental wave (F _1,1 ), in particular the amplitudes of a fundamental wave (F _1,1 ) and at least the first harmonic wave (F _2,1 ) are used, wherein preferably the fundamental wave (F _{1, 1} ) and / or at least the first harmonic (F _2,1 ) are calculated by a Fourier analysis of the periodic distance measurement, particularly preferably calculated by a Taylor series development and a Fourier analysis of the periodic distance measurement. A method according to claim 11, characterized in that in the calculation of the fundamental wave (F _1,1 ) and / or at least the first harmonic wave (F _2,1 ) is assumed that the amplitudes of the fundamental wave (F _1,1 ) and / or at least the first harmonic (F _2.1 ) is greater than or equal to zero. Method according to one of claims 7 to 12, characterized in that the angles β ₁ and γ ₁ and the amplitudes Ĉ ₁ and B ₁ for determining the position

and the orientation described by the vector

the at least one laser distance sensor ( 2 ) with the equations

where μ _{1 is} the phase of the fundamental wave of l ₁ (φ) and η _{1 is} the phase of the first harmonic of l ₁ (φ), ĉ _z1 = sign (c _z1 ) the z-orientation of the laser ( 8th . 28 ) indicates to the turntable, δ is the tilt angle of the turntable against the rotation axis (z), and F _{1,1 is} the measured amplitude of the fundamental and F _{2,1 is} the measured amplitude of the first harmonic. Method according to one of the preceding claims, characterized in that the distance measurements are carried out with a laser triangulation method and / or that the at least one laser distance sensor ( 2 ) is calibrated in the course of alignment based on the measured data and / or the quantities calculated therefrom. Method according to one of the preceding claims, characterized in that the relative position and orientation of at least two laser distance sensors ( 2 ) and thereby uncertainties due to errors in the assessment of the position and geometry of the calibration body ( 12 . 32 ). Method for measuring the thickness of a body or a coating of a coated body in a measuring setup, wherein at least one laser distance sensor ( 2 ) whose position and orientation to the calibration body ( 12 . 32 ) was determined by a method according to one of the preceding claims or which was previously determined in the measurement setup with a method according to one of claims 2 to 15 against a calibration body ( 12 . 32 ) was aligned. Method according to claim 16, characterized by the chronological steps E) removal of the calibration body ( 12 . 32 ) from the measurement setup; F) inserting the body to be measured in a storage, which has a known position and orientation to the previously stored calibration body ( 12 . 32 ) in the measurement setup; and G) measuring the thickness of the body or its coating by means of the at least one aligned and positioned laser distance sensor (US Pat. 2 ) and / or measuring the thickness of the body or its coating, wherein the position and the orientation of the at least one laser distance sensor ( 2 ) is mathematically taken into account. Device for carrying out a method according to one of the preceding claims, in which the device comprises at least one laser distance sensor ( 2 ) and a bearing for a body to be measured, wherein the laser distance sensor ( 2 ) a laser ( 8th . 28 ) and a sensor ( 10 ), the storage for holding a calibration body ( 12 . 32 ) is designed with at least regionally well-defined surface and the calibration body ( 12 . 32 ) is defined in the device movable. Device according to claim 18, characterized in that the calibration body ( 12 . 32 ) is rotatably mounted in the device or is storable and the calibration body ( 12 . 32 ) is rotatable about defined angles (φ) about a rotation axis (z) and / or is rotatable with at least one defined angular velocity (ω). Device according to claim 19, characterized in that the calibration body ( 12 . 32 ) is a disc which is inclined relative to the axis of rotation (z), preferably tilted by a tilt angle (δ) between 5 ° and 60 °, particularly preferably tilted by a tilt angle (δ) between 15 ° and 30 °, especially preferably tilted by a tilt angle (δ) between 20 ° to 25 °.

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