EP1931942A1

EP1931942A1 - Method for contactlessly and dynamically recording the profile of a solid body

Info

Publication number: EP1931942A1
Application number: EP06807017A
Authority: EP
Inventors: Manfred Hoffmann; Michael J. Walter; Dieter Hoffmann; Andreas Brinkmann
Original assignee: Gutehoffnungshutte Radsatz GmbH
Current assignee: Gutehoffnungshutte Radsatz GmbH
Priority date: 2005-10-06
Filing date: 2006-10-05
Publication date: 2008-06-18
Also published as: ES2307467T1; JP2010506135A; WO2007039641A1; RU2008117999A; CN101479567A

Abstract

The invention relates to a method for contactlessly and dynamically recording the profile (P) of a solid body (1). According to said invention, at least one light beam, which is generated by a laser device (2) and expanded in such a way that at least one linear light band (3) is formed is projected onto the moving surface of the solid body (1) and a light (RL) reflected by the solid body surface (1, 1a), inside an optical imaging device (5), whose optical axis is positioned at a fixed triangulation angle to the projecting direction of the laser device (2) and which is located at a fixed base distance from the laser device (2) is focussed and detected with a frequency which is higher with regard to the motion rate (v) of the solid body (1) by means of a planiform light-absorbing element (6). Afterwards, the measured values of the profile (P) are obtained from signals delivered by the light-absorbing element (6) according to the triangulation angle and the base distance (B) in a data processing device by means of trigonometric relations and by combination of correction values determined according to the motion rate (v) of the solid body (1) and said values are stored in the form of a profilogram (PG) in the data processing device, wherein the determination of an image triggering (106A, 106B, 106C), for which the signal delivered by the light-absorbing element (6) are selected in such a way that it makes it possible to extract the measured values (zB) of the profile (P), is carried out in a reception loop (100)

Description

Gutehoffnungshütte Radsatz GmbH, Gartenstrasse 40, D-46145 Oberhausen

Method for non-contact dynamic detection of the profile of a solid

The present invention relates to a non-contact method for the dynamic detection of the profile of a solid, in particular for the purpose of determining wear occurring on the solid.

To determine wear, so-called model test stands (for example from Amsler, Laffon-Eichinger et al.) Are frequently used, on which test specimens of the materials which are tested for their tribological properties in a friction pair occurring in a specific application. However, the transfer of the parameters determined in this way to the specific application, for example to friction bodies of a much larger dimension than that of the test bodies, encounters the difficulty that the tests can only provide orientation values, since the influencing variables on the wear represent a complex conditional structure, on a model test bench never exactly matches the real conditions. Therefore, tribological investigations on the real object are essential for important applications, but often encounter the problem that a component whose wear is to be examined is removed after a certain period of operation and then, e.g. must be examined with regard to the wear occurring under determination of the surface profile, which is usually associated with a considerable effort.

Profile surveys on solids, ie, the preparation of profilograms of the surface, can be known to be carried out by tactile methods, for example using a stylus instrument, the latter being a method based on the contact of a stylus tip with the solid state the measuring range is less than one millimeter and in which, for example, in the centimeter range no measured values can be obtained. The measuring time is several seconds per measuring point and the method is disadvantageously not suitable for a rough measuring environment.

For the static detection of solid-state profiles, various non-contact optical methods are known. Such methods and the associated devices are, as described for example in the monograph by Bernd Breuckmann "Image Processing and Optical Measurement", Munich: Franzis', 1993, Chapter 6, also subsumed under the term "topometric 3D measurement". Laser triangulation is described here as one of the topometric methods, triangulation being taken to mean a measuring method first developed by Snellius in 1615 for ground surveying, in which a measured variable to be determined is determined indirectly from other measured variables using trigonometric relationships.

In laser triangulation, a light spot is projected onto a measurement object by means of a laser. The light reflected from the object, in particular scattered light, is imaged on a light-receiving element, such as a position-sensitive detector. Such detectors are also referred to in English as PSD "position sensitive devices". From the geometry of the optical structure and the angle between the direction of illumination and observation, the position, in particular the altitude, of the observed object point is determined by triangulation. Today, laser triangulation methods allow non-contact measurements in the distance range of up to several meters with depth resolutions down to the μm range.

An extension of the laser triangulation represents a known, also described in said monograph method, in which the laser light beam is expanded to a linear band of light, a so-called light section. For detecting the reflected light, a planar detector may be used, such as a video camera. The evaluation is again based on the triangulation. Characteristic of this method is a measuring range of profile height from 1 mm to 1 m with a resolution of about 1 to 50 thousandths of this area. In the abovementioned monograph, a fundamental suitability of the light-section method for use in continuously moving objects is postulated, but there are no details of the possible uses and limits. However, a method for dynamic, ie real-time detection of the profile of a moving solid encounters in practice the problem that the movement of the surface to be measured causes distortions that make a procedure using the classical triangulation method impossible, since in this way none of the reality corresponding measured values can be obtained.

The present invention has for its object to provide a non-contact method for dynamic detection of the profile of a solid, of the type described above, which allows short measurement times, at least three orders of magnitude covering measuring range, such as tenths of millimeters, millimeters and centimeters, includes a high accuracy guaranteed and that can be used under rough operating conditions in particular for the determination of wear of components.

According to the invention, this is achieved by such a method in which at least one light beam generated by a laser device and expanded to at least one line-shaped light band is projected onto at least one area of the surface of the solid body, wherein the solid body is moved past the laser device and that of the area of the Surface of the solid reflected light in an imaging device whose optical axis is at a fixed triangulation to the projection direction of the laser device and which is arranged at a fixed base distance to the laser device, focused and detected with a relation to a speed of movement of the solid high frequency by means of a surface-shaped light receiving element is, according to which emitted from the light receiving element signals in dependence on the triangulation angle and the base distance in a data processing device by trigonometric relationship the measured values of the profile are obtained and stored in the data processing system as a profilogram, wherein the determination of an image triggering for the signals emitted by the light receiving element for Extraction of the measured values of the profile are selected, takes place in a recording loop.

The solid body may be a rotationally symmetrical body, in particular a vehicle wheel, which is a translational one, or preferably a rolling movement, which executes a rolling movement. The method according to the invention thus represents an extremely advantageous possibility to determine profiles of a wheel while passing by and draw conclusions about the wear therefrom.

In addition to a possible combination of the measured values with correction values determined in accordance with the movement speed of the solid, which advantageously permit profile determination not "blurred" by the speed, the measured values of the profile under linkage can also be used in a preferred case for distortion-free determination of the profilogram with correction values determined according to the area of the surface of the solid.

In the sense of a complete profile detection, it is advantageous if a plurality of profilograms are determined as partial profilograms using at least three areas of light bands projecting on different sides of the surface of the solid, and the partial profilograms are stored in the data processing system and from this Overall profile is obtained. In the case of a substantially cylindrical or annular solid body, such as a vehicle wheel, in the basic shape, the at least three regions onto which the light bands are projected can preferably lie on the two cover surfaces and on the lateral surface of the cylinder or ring. The profilogram, the partial profilograms and / or the overall profilogram can then be compared with one or more reference profilograms and the respective deviations from the respective reference profilogram determined, which is a measure of the wear that has occurred or a measure of whether the occurred Wear is still within a tolerable range. With the help of correlative links between the expected stress duration of the solid and the determined Wear can be made in this context, an extrapolierende statement about how long a further period of use harmless or when a re-examination seems necessary.

Furthermore, it is of advantage if the profilogram, the partial profilograms, the overall profilogram, the respective reference profilogram and / or the respective deviations are related to a fixed, long-term invariable basic geometrical variable, such as a non-wearing inner rim circumference. In this way, for example, the wear surface can be represented as a development on which the height profile relative to the base size is represented by suitable means of representation. For example, For example, the profilogram, the partial profilograms, the overall profilogram, the respective reference profilogram and / or the respective deviations can be visualized in a display device, such as a display.

The basic size can be determined with advantage from at least three measured values, which are also determined by non-contact dynamic measurements on the moving solid, which are made in the same manner as the acquisition of the profilogram or the acquisition of the partial profilograms. For this purpose, there is either the possibility that the measurements on the moving solid at predetermined time intervals at least three times by means of a single expanded to a linear light band light beam or that the measurements simultaneously by at least three, each expanded to a linear light band light beams at a predetermined distance of the areas Surface of the solid on which the light bands are projected done.

As light-receiving elements, it is possible with advantage to use digitized signal-providing devices, such as a trigger-controlled CCD camera or position-sensitive device, such as photodiode arrays. In the first case, it should be noted that the light-receiving element is sensitive to the light intensity, while it provides adequate signals in the second case of the amount of light.

In the receiving loop provided in accordance with the invention, a distance signal can in particular be provided by a laser distance sensor, which is in particular the light receiving element, after a signal conditioning be provided, ie it can be a determination of states of the solid body, such as the distance to the laser device and a change over time of this distance as a first derivative (speed) and - if accelerated movement - also second derivative of the way after the time (acceleration). In the signal conditioning can thereby find electrical voltages as a result of an analog provision by the laser distance sensor input.

As regards the laser device used according to the invention, the following characteristics have proven to be particularly advantageous:

under the aspect of a high reproducibility of the results and a high accuracy of measurement: wavelength of the generated light band in the range of 400 nm to 1000 nm, in particular in the range of 650 to 700 nm;

also under this aspect: power of the laser device in the range of 0.5 to 50 mW;

under the aspect of a high work safety (laser class 2 according to DIN EN 60825-1: 2001-11): Wavelength of the light band in the visible range and limit of the accessible radiation (GZS) of the laser device less than 1 mW - it should be noted that with a laser power , which is higher than 1 mW, can be lowered by appropriate measures, the limit of the accessible radiation to the required value;

under the aspect of minimization of costs for the process (cost): use of a continuous wave (cw) diode, for example of a semiconductor material, such as GaAs, AIGaAs, InGaP, GaAsSb, InP, PbSnTe or the like, preferably a VLD (visible laser diode), similar to that used in a laser pointer - a visible light band also facilitates the adjustment of the laser device relative to the solid to be measured. As far as the measuring conditions of the method according to the invention are concerned, the following characteristics have proved to be particularly advantageous or optimal for a profilometry for the purpose of wear testing, with a resolution of less than 2.0 for the respectively determined profilogram, the partial profilograms and the overall profilogram mm, in particular less than 0.5 mm, can be achieved.

Width of the light band: in the range of 0.3 mm to 6.5 mm, in particular in the range of 0.8 mm to 2.2 mm - by divergence occurs with possibly intentionally increasing average working distance (measuring distance) on an enlarged width of the light band, but reduces the accuracy of measurement;

Length of the light band: in the range of 50 mm to 750 mm, in particular in the range of 200 mm to 400 mm - according to the geometry of the area of the surface of the solid to be measured;

Triangulation angle: in the range of 15 ° to 40 °, in particular in the range of 20 ° mm to 30 °, an increased angle increases the accuracy but also the risk of inhomogeneous illumination of the surface of the solid and the occurrence of shadowing;

Base distance between the imaging device, in particular the center of a focusing lens of the imaging device, and the optical axis laser device in the range of 30 mm to 450 mm, in particular in the range of 60 mm to 270 mm.

average working distance of the laser device and / or the imaging device from the area of the surface of the solid on which the light band is projected: in the range of 20 mm to 650 mm, in particular in the range of 150 mm to 350 mm;

Speed of an optionally translatory movement of the solid: less than 3.5 m / s, preferably less than 1.5 m / s; Angular velocity of an optionally rotating movement of the solid-state particle :: I less than 15 s ^' \ preferably less than 6 s ^"1 and preferably constant;

Frequency with which the light reflected from the surface of the solid light is detected by means of the light receiving element: in the range of 25 Hz to 100 kHz, preferably in the range of 1 kHz to 10 kHz.

As far as the frequency is concerned, it must be adapted to the speed of movement of the solid - a higher frequency reduces the influence of the velocity of the solid on the distortion of the signals of the light-receiving element. To determine the correction values determined in accordance with the movement speed, which may be, in particular, vectorial factors and / or summands proportional to the nature of the measured values of the profilogram, it is therefore advantageous to correlate the movement speed with the frequency of the Detecting the reflected light done. For the given ranges of the speed of the movement of the solid, advantageously no non-linearities are to be considered.

The correction values determined in accordance with the area of the surface of the solid may, in particular, be vectorial factors corresponding to the nature of the measured values of the profile, and / or summands depending on a radius of the rotationally symmetrical body, where the said radius is the same long-term invariable geometric Basis variable that serves as a reference for determining the profilograms.

Further advantageous embodiments of the invention are contained in the subclaims and in the following detailed description.

Reference to an illustrated by the accompanying drawings embodiment, the invention is explained in detail. Show Fig. 1 in a schematic side view, a schematic representation of

An illustration of the method according to the invention,

Fig. 2 in a schematic perspective view, another principal

Representation to illustrate the method according to the invention,

3 is a perspective view of a wear test stand for wheels of a rail vehicle, such as railway wheels, wherein the inventive method is used,

4 shows a detail corresponding to FIG. 3, from a viewing angle selected with respect to the direction of movement from the front to the outside of a wheel,

Fig. 5 is a Fig. 3 corresponding detail, but from a respect to the

Direction of movement from the rear to the inside of a wheel

6 is a schematic representation of the procedure in the determination of a geometric base size to which a profilogram determined according to the invention can be obtained,

7 and 8 representations of inventively determined profilograms,

9 shows a program flow chart for the application of the invention

Process.

In the various figures of the drawing, the same parts are always provided with the same reference numerals, so that they are usually described only once in each case.

As is first shown in FIG. 1 in a two-dimensional representation with respect to the measurement object, a solid 1 moved at the speed v, a laser device 2 emanates from a laser device 2 in accordance with the method according to the invention Focused light beam by means of an optical system, not shown, so that in a measuring range Dz, which results from the difference of a maximum measurable value z _max and a minimum measurable value z _{min of} the depth or the profile height z, the width b of the beam in a predetermined Area is located. The light beam is widened to a light band 3, as shown in three-dimensional view Fig. 2.

At the point of incidence z _{A of} the light band on the surface of the solid 1 is formed by diffuse light scattering (reflected light RL) a measuring spot, which can also be perceived from directions that differ from the determined by the optical axis OO of the laser device 2 incident direction.

If the measuring spot under the triangulation angle φ is then imaged by a corresponding focusing lens 4 of an imaging device 5 onto a sheet-like light receiving element 6, then depending on the distance of the point of incidence z _A a position X _A of a minimum value x _min and a maximum value x _max Image spot on the light receiving element 6 a.

The geometry of the structure of the device used for the method according to the invention is determined next to the fixed triangulation angle φ by a fixed base distance B of the optical axis A-A focusing optics 4 of the imaging device 5 to the position of the laser device 2 - determined by the optical axis O-O.

Using trigonometric relationships, from the measured image spot position x _A, the distance of the impact location z _A , ie the distance of the surface of the solid 1 from the laser device 2 according to the equation

ZA = H / (1-B / X _A ) (1)

where H is a distance of the focusing lens 4 of the imaging device 5 to its light receiving element 6, as illustrated in FIG.

The relative measurement accuracy dz _A / z _A results here too CIZA / ZA = 1 / (1 - XA / B) * CIXA / XA (2),

wherein the relative resolution CIX _A / X _{A of} the image spot position depends on the velocity v of the solid in relation to a frequency f at which the reflected light RL is picked up by the image pickup element 6, and the signal noise and the type of the light receiving element 6. The quantity dzA in equation (2) represents an absolute value of the measurement accuracy.

To increase the resolution, the final measured values z _{B of} the profile (denoted by P in FIGS. 1 and 2) are obtained by combining the values Z _A with correction values Kv determined in accordance with the movement speed v of the solid 1, which are in particular vectorial, the movement speed v is proportional factors and / or summands. In this case, to determine the correction values Kv determined in accordance with the movement speed v, a correlation of the movement speed v with the frequency f of the detection of the reflected light RL takes place.

By changing the geometry described above, in particular the base distance B, the triangulation angle φ and / or an average working distance (illustrated in FIG. 1 by the length L) of the imaging device 5 or the laser device 2 from the area of the surface of the solid 1, On which the light band 3 is projected, advantageously the measuring range Dz and, associated therewith, the measuring accuracy dz _A / z _A can be freely adjusted simply by the appropriate choice of the geometrical sizes of the structure. The individual devices need not necessarily, as shown in Fig. 1, to be covered by a common housing 7. An enlargement of the measuring range Dz causes a reduction of the measuring accuracy and vice versa.

In the illustrated embodiment, a SONY HCC 400 camera was used as the light receiving element 6. Since the resolution of the size of the measuring range, ie the measuring range Dz, depending, this means for the dimensioning of an apparatus for performing the method according to the invention that the number of detecting camera heads is directly dependent on the required or selected resolution. To record the topography of a three-dimensional solid 1, as already mentioned and illustrated in FIG. 2, the system, which has hitherto only been considered in two dimensions, is considered in three dimensions. That is, it is worked with a widened to a light band 3 laser beam. This is called a light-section method. After the reflected light RL has been detected by the sheet-shaped light receiving element 6 and determined from the light receiving element 6 signals taking into account the Triangulationswinkels φ and the base distance B in a data processing device, not shown, such as a PC, the measured values of the profile P determines and in the data processing system as Profilogram PG are stored. Representing such a profilogram PG, in the schematized representation of FIG. 2, is the correspondingly designated polyline on the light-receiving element 6. Profilograms from real measurements are shown in different representations in FIGS. 7 and 8.

As on the surface of the solid 1 lying areas of light bands 3 projecting laser device 2 was a commercial line laser module L200 with a line length LB (Fig. 2) of 300 mm and a line width b (Fig. 1) of 1, 5 mm, a laser power of 30 mW and with visible red light (wavelength 680 nm) used.

Fig. 3 shows - as also mentioned above - a typical application of the method according to the invention, namely for the determination of wear. The illustration shows a perspective view of a wear test stand 8, which is designed for rolling on rails 9, with a translational speed v and an angular velocity ω over, moving wheels 1a designed as to be measured solid 1.

It can be seen from the graphic representation that it is provided in this wear test stand 8, a plurality of profilograms PG as partial profilograms (also referred to in Fig. 7 as PG _a , PGb and PG _C ) using three, on different sides Di, D ₂ , M the regions of the surface of the solid 1 lying light bands 3a, 3b, 3c projecting laser devices 2 and the associated imaging devices 5 are determined. The partial profilograms PG _a , PGb and PG _C can be found in the Data processing system stored and from an overall profile GPG are obtained.

The wheel 1a of the rail vehicle 10 represents a rotationally symmetrical, in the basic shape substantially cylindrical or annular solid 1, wherein the three areas on which the light bands 3a, 3b, 3c are projected on the two cover surfaces Di, D ₂ and lie on the lateral surface M of the cylinder or the ring. As shown in FIG. 3 and in detail in FIGS. 4 and 5, the three light bands 3a, 3b, 3c need not form a closed polyline for the determination of the overall profileogram GPG. It is also not necessary for the light band 3b projected onto the lateral surface M to extend parallel to the axis of the wheel 1a. A corresponding deviation from the axis parallelism can be compensated for by obtaining the measured values z _{B of} the profile P by linking with correction values Ko determined in accordance with the area of the surface of the solid.

Fig. 5 illustrates the first and Fig. 6, the second of the possibilities mentioned around a Radkranzinnenradius R of the wheel 1a as a fixed, long-term immutable geometric base size to which the profilogram PG, the partial profilograms PG _a , PGb, PGc and the overall profile GPG are related can determine. The radius R is in both cases determined from at least three measured values zi, Z ₂ , Z ₃ , which are determined by contactless dynamic measurements on the moving wheel 1a and which are made in the same way as the acquisition of the profilogram PG or the detection subprofiles PG _a , PGb, PG _C.

According to Fig. 5, the non-contact dynamic measurements on the rolling wheel 1a simultaneously by means of at least three, each to a linear band of light 3c1, 3c2, 3c3 expanded light beams at each predetermined intervals N1, N2 of the areas of the surface of the solid 1, to which the light bands 3c1 , 3c2, 3c3 are projected.

According to FIG. 6, the non-contact dynamic measurements on the rolling wheel 1a are made at predetermined time intervals Δt at least three times ti, t ₂ , t ₃ by means of a single light beam expanded to a line-shaped light band 3c. The measurements thus take place unidirectionally, ie with the same orientation of the respective light bands 3c, 3c1, 3c2, 3c3, in each case at three points Si, S2, S3, three measured values zi, Z ₂ , z ₃ lying on a circular arc of radius R as Ordinatenwerte the points Si, S2, S3 are determined in a Cartesian coordinate system. The measured values zi, Z ₂ , z ₃ assigned to the points Si, S ₂ , S ₃ according to the manner shown in FIG. 6 correspond in each case to a measuring length of the line-shaped light band 3c or 3c1, 3c2, 3c3. The measurement lengths of the line-shaped light band 3c or 3c1, 3c2, 3c3 can be easily transformed for this assignment such that the measured values zi, Z ₂ , Z3 each represent half the length of a chord sh, sl ₂ , SI ₃ through the circular arc. Each of these measurement values zi, Z _2, Z xi ₃ corresponding abscissa values, _X2, X3 - of Figure 6, respectively as the three points in time ti, .2, ₃ present distances t of the circle center point Mi, M _2, M ₃ by the light band. 3c are shown either in the first case from the distances N1, N2 according to FIG. 5 or in the second case from the time intervals Δt predetermined by the three times ti, t ₂ , t _{3 of} the measurement by multiplying the time intervals Δt by the angular velocity ω , The angular velocity ω can either be fixed or likewise determined by non-contact dynamic measurements on the rolling wheel 1a by means of one or more linear light bands 3. The evaluation is facilitated if the speed, ie on the one hand the rotating and thus on the other hand also the translatory movement of the wheel 1a is constant.

The reference radius R of the rolling wheel 1a can be determined from the following equation system after the determination of the measured values zi, Z ₂ , Z ₃ :

R ² = X1 ² + Z ₁ ² (3)

R ² = X ₂ ² + Z ₂ ² (4)

R ² = X ₃ ² + Z ₃ ² (5)

Xi - X ₂ = k * (x ₂ - X ₃ ) (6).

The quantities R and xi, X ₂ and X ₃ each represent unknowns therein. The quantity k in equation (6) is a known factor corresponding to the predetermined time intervals Δt or the distances N1, N2 of the areas of the surface of the wheel 1a, of the for the preferred case of constant time intervals Δt or equidistant distances N1, N2 assumes the value 1.

The determined radius R can on the one hand serve as a baseline for the measured values Z _{B of} the profile height, which are determined on the lateral surface M of the wheel 1a, on the other hand it is possible to determine this radius R for the determination of correction values Ko corresponding to that of the light band 3 or 3a, 3b, 3c 3c1, 3c2, 3c3 illuminated area of the surface of the solid 1 are taken into account. The necessity of taking into account such correction values Ko arises, for example, from the fact that the chords sh, Sl ₂ , Sl ₃ in FIG. 6 each span different central angles, as a result of which different local profile distortions occur. The central angles are between 0 ° in the first extreme case when the light band 3c forms a tangent to the circumference of the considered circular arc of the wheel 1a and 180 ° in the other extreme case when the light band 3c with the diameter 2R of the considered circular arc of the wheel 1a coincides. The largest chord length sb contains most information about the profile to be determined and has the least local distortion.

For these reasons, it is therefore extremely advantageous if the overall profile GPG shown in Fig. 7 of a rolling solid 1, in the illustrated case of the wheel 1a, from three of the two top surfaces Di, D ₂ and on the lateral surface M simultaneously to a detection time t _k certain Teilprofilogrammen is obtained, wherein the detection time t _{k of} the individual Teilprofilogramme is selected such that a measured at this detection time t _k measured value Z _k - in the present case Z ₃ - from at least three on a circular arc with the radius R in one of the top surfaces Di, D ₂ lying, in each case at successive times ti, t ₂ , t ₃ and unidirectionally from the respective length LB of the linear band of light 3c, 3c1, 3c2, 3c3 determined measured values zi, Z ₂ , Z ₃ , each half the length of a Shear sh, Sl ₂ , Sl ₃ correspond by the arc, takes a maximum. Of course, the application of this criterion of the choice of the detection time t _{k is} not limited to three measured values zi, Z ₂ , Z ₃ . On the basis of more than three measured values zi, Z ₂ , Z ₃ , even better results can be achieved insofar as the determined largest half chord length Sl ₃ differs less from the radius R or assumes the same value as the radius R. FIG. 7 further shows that the respective profilogram PG, the partial profilograms PG _a , PGb, PGc and / or the overall profilogram GPG are each provided with one or more reference profilograms (s) - in the drawing a reference profilogram BP1 for maximum measured values z _{B of} the profile P and a Bezugsprofilo- gram BP2 for minimum measured values Z _{B of} the profile P compared and the respective deviations .DELTA.PG can be determined by the respective reference profile BP1, BP2. In the case shown, such deviations occur in the area shown in dash-dotted lines. The reference profilograms BP1, BP2 can preferably be admissible nominal dimensions, but a reference profilogram BP1, BP2 could also be a stored data set of measured values z _B from an earlier measurement, so that the respective deviations ΔPG provide information about how large the the past measurement has occurred wear.

While the representation of the profile P in FIG. 7 is only a two-dimensional one, in which the measured values Z _{B of} the profile P are shown as a line vector x, z over the cross section Q of the wheel 1a, the illustration of the profile P in FIG 8 shows the three-dimensional character of the method according to the invention. In FIG. 8 the measured values Z _{B of} the profile P are shown as vectors x, y, z by means of different gray values over the development of the cover surface Di of the wheel 1a determined with the aid of the above-mentioned radius R. The absolute value of the resolution dz _A according to equation (2) is less than 0.5 mm, e.g. B. at 0.4 mm. The designated Q, marked by encircling line indicates the cross-section shown in Fig. 7 Q of the wheel 1a, wherein at this point - as indicated - the partial profile PG _{a of} FIG. 7 is present. Instead of the gray values, in order to increase the clarity in a suitable display, colors can also be used for display.

The inventive method advantageously allows the detection of a profile P in an extremely short determination time. Thus, in a time of 5 seconds by means of both sides of rails 9, on which a rail vehicle 10 rolls past, arranged laser devices 2 and imaging devices 5 for five bogies, ie ten sets of wheels, ie 20 wheels 1a, respectively, a three-dimensional overall profile GPG are created. The program flow chart shown in FIG. 9 for the application of the method according to the invention is particularly tailored to the non-contact detection of the profile of wheels of a rail vehicle, such as railway wheels. Such a wheel is - as mentioned - provided with the reference numeral 1a shown on the rail vehicle 10 in Fig. 3 by way of example.

In particular, the program flowchart comprises a pick-up loop 100 for dynamically detecting the profile P of the solid 1 or 1a, which is started after a request 90 from a server for system start-up operations, which in FIG. 9 is indicated by the box marked with the reference numeral 95 are symbolized and may include the activation of a traffic light for the rail vehicle 10, the activation of a trigger for image triggering in the light receiving element 6 and switching on the laser device 2.

In the receiving loop 100, a distance signal 103 is provided in particular by a laser distance sensor 101, which is in particular the light receiving element 6, after a signal conditioning 102, that is to say a spacing signal 103. H. there is a determination of states of the solid body 1, 1a, such as the distance to the laser device 2 and a temporal change of this distance as a first derivative (speed) and - if accelerated movement - also second derivative of the way after the time (acceleration). In the signal conditioning 102 can thereby find electrical voltages as a result of an analog provision by the laser distance sensor 101 input.

In the method step "signal evaluation" 104, the determination of either - with reference to the method described in connection with FIG. 5 - then takes place according to the determined initial states of the solid 1, 1 a, in particular from the distance signal 103 - a detection time at which three, for three different light bands 3c1, 3c2, 3c3 emitted from the light receiving element 6, further determined to obtain the measured values z _{B of} the profile P signals are first recorded, or - with reference to the method described in connection with FIG. 6 - of at least three times ti, t ₂ , t ₃ , at which for only one light band 3c emitted from the light receiving element 6 Signals that are subsequently used to obtain the measured values z _{B of} the profile P, are first recorded.

In detail, this means that under the action of initiators 105A, 105B, 105C - depending on the method - in a light receiving element 6, z. B. in the camera, or in three light receiving elements 6, each image triggering 106A, 106B, 106C takes place. The captured images can be stored in a frame buffer, d. H. a, preferably cyclically operating, sequential image memory, for. As the camera, cached.

In this case, the image triggering 106A, 106B, 106C should preferably take place with the criterion of the greatest possible proximity to time at the time at which the initial states of the solid state 1, 1a were determined, since the signals present in each case are more advantageous for the signal evaluation in this case Differ only slightly, d. H. in particular, the distance from the laser device 2 has changed only slightly.

The signal evaluation 104, preferably of the distance signal 103, can be carried out in particular by means of a so-called "Easy Logic", which can be advantageously integrated into an existing data processing device "Easy Logic" is understood to mean a programmable device which allows various Configure time-based logical sequences. Such devices, which can also be subsumed under the name PLD - Programmable Logic Devices - or in particular under the name SPLD - Simple Programmable Logic Devices - allow a user with the help of suitable software, preferably a Relay Ladder Logic, - for example by a Programming in the system (InSystem-Programming, ISP) - a desired predetermined logical and temporal relation between one or more inputs, in the present case in particular the distance signal 103, and one or more outputs, in the present case in particular the initiators 105A, 105B, 105C. In the Easy Logic can thus be set to implement the method according to the invention, a time range in which from the point of view of the expected image quality an image recording allowed or preferably also appears optimal. This time range can be, for example, an area in which the according to the Area of the surface of the solid 1, 1a certain correction values Ko and / or according to the speed of movement v of the solid 1, 1a certain correction values Kv - preferably as fixed values, ie without dynamization - have their validity. In comparison with discrete logic devices, the use of Easy Logic leads to a reduced expenditure on equipment (printed circuit boards, connectors, connections) and to a reduced installation effort (wiring, bonding) in circuit production and to a more compact possible construction.

After the image triggering 106A, 106B, 106C, in which the images are acquired, in particular, as image matrices 107A, 107B, 107C, a selection of images, in particular dependent on the speed of the solid 1, 1a, takes place, for which in the program flowchart the reference symbol "IS" (FIG. The image matrix 107, which is present as a result of the image selection IS and representative of the measured values Z _{B of} the profile P, is stored - preferably with the respectively associated values of the distance or measuring location and / or time, eg at one of the times t i, ₂ or ₃ - at the same time, the resetting 109 of a timer is performed at the same time as described by the recording loop 100.

The termination criteria for the processes in the receiving loop 100 are the condition checks illustrated by the boxes labeled 110 and 111. On the one hand, it is checked (box 110) whether the timer is already running for more than 10 seconds and, on the other hand, whether all the axles of the rail vehicle 10 have been picked up (box 111). If one of these conditions applies, the image acquisition is stopped (box 112). The question of whether the timer is already running for more than 10 s, aims to determine whether the solid 1 or 1a may have come to a standstill. After stopping 112 image capture, the stored image data 108 may be sent to the server (box 113). At the same time, system stop operations such as "turn off trigger", "turn off laser device 2" and "traffic light control for rail vehicle 10" may occur, which are symbolized by the box labeled with reference numeral 195. To realize the processes shown in the program flow according to FIG. 9, in particular the receiving loop 100, the corresponding hardware can be incorporated into the test bench 8 according to FIG. 3, whereby advantageously a client-server circuit can be realized in which the client on track 9 and the server is located in a remote location.

The present invention is not limited to the exemplary embodiment illustrated, but includes all means and measures which have the same effect in the sense of the invention. So there is another possibility in the application of so-called strip projection method using structured or coded illumination. These methods are likewise based on the triangulation principle, wherein the entire solid body 1 is illuminated by a projector corresponding to the laser device 2 with a mathematically predetermined light pattern. During the recording, the light pattern is changed in a certain way so that it is possible to determine from the resulting intensity distribution of the recorded image on the topography.

Furthermore, the skilled person can supplement the invention by additional advantageous measures, without departing from the scope of the invention. Thus, suitable software modules can be used for the execution of all arithmetic operations - such as those of the specified equations (1) to (6) in the data processing device.

Furthermore, the invention is not limited to the feature combination defined in claim 1, but may also be defined by any other combination of certain features of all individually disclosed features. This means that in principle virtually every individual feature of claim 1 can be omitted or replaced by at least one individual feature disclosed elsewhere in the application. In this respect, the claim 1 is to be understood only as a first formulation attempt for an invention. reference numeral

1 solid

1a wheel

2 laser device

3, 3a, 3b, 3c, 3c1, 3c2, 3c3 light bands

4 lens of 5

5 imaging device

6 light receiving element

7 housing

8 wear test stand

9 rail

10 rail vehicle

90 request from the server

95 System startup

100 recording loop

101 laser distance sensor

102 signal conditioning

103 distance signal

104 signal evaluation

105A, 105B, 105C Initiators for 106A, 106B, 106C

106A, 106B, 106C Image triggering

107A, 107B, 107C are image matrices of 106A, 106B, 106C

107 image matrix of IS

108 image storage

109 Timer Reset

110, 111 Testing of Demolition Conditions for 100

112 image recording stop

113 Data transmission to server

195 System stop AA optical axis of 6

B base distance b width of 3, 3a, 3b, 3c, 3c1, 3c2, 3c3

Dz Measuring range of z dz _A Resolution of Σ _A

Di ₁ D ₂ cover areas of 1, 1a f frequency

GPG overall profilogram

H distance 4/6 (Fig. 1)

IS image selection in 100

Kv correction value corresponding to v, ω

Ko correction value corresponding to range / position of

3, 3a, 3b, 3c, 3c1, 3c2, 3c3 k factor corresponding to N1, N2 and Δt, respectively

L working distance

LL line length of 3, 3a, 3b, 3c, 3c1, 3c2,

3c3

M lateral surface of 1, 1a

N1, N2 distances between 3c1, 3c2, 3c3

0-0 optical axis of 2

P profile

PG profilograms

PG _a , PGb, PGc partial profilograms

R radius

RL reflected light

V translational speed of 1, 1a tk. t1. t2.t3 measuring times

Si, S ₂ , S3 points on perimeter around R

Sh, Sl ₂ , Sl ₃ chord lengths at Si, S ₂ , S3

X length coordinate

XA image spot location from RL to 6

Xmax maximum value of x

Xmin minimum value of x X1, X2, X3 Measured values Length at Si, S ₂ , S3 y Length coordinate

Z height coordinate

ZA measured value, impingement of 3, 3a, 3b, 3c,

3c 1, 3c2, 3c3

For example, corrected measured value from Z _A

Zmax maximum value of z

Zmin minimum value of z

Zi ₁ Z ₂ , Z ₃ Measured values height at Si, S ₂ , S3

ΔPG profile deviation

Δt time interval φ triangulation angle

Claims

claims

1. A method for non-contact dynamic detection of the profile (P) of a solid (1, 1a), in particular for the purpose of determining on the solid body (1, 1a) occurred wear, wherein at least one of a laser device (2) generated, at least a light beam (3, 3a, 3b, 3c, 3c1, 3c2, 3c3) is projected onto at least one area of the surface of the solid (1, 1a), the solid (1, 1a) being projected on the laser device (2) is moved past and the light (RL) reflected from the area of the surface of the solid (1, 1a) in an imaging device (5) whose optical axis (AA) at a fixed triangulation angle (φ) to the projection direction (OO) of the laser device (2 ) and which is arranged at a fixed base distance (B) to the laser device (2), focused and with a relation to a speed of movement (v) of the solid (1, 1 a) high frequency (f) by means of a fl depending on the triangulation angle (φ) and the base distance (B) in a data processing device by trigonometric relationships and under linkage with correspondingly the measured values (Z _B ) of the profile (P) and stored in the data processing device as a profilogram (PG), wherein the determination of an image triggering (106A, 106B, 106C), for the light receiving element (6) output signals for obtaining the measured values (Z _B ) of the profile (P) are selected in a recording loop (100).

2. Method according to claim 1, characterized in that the measured values (z _B ) of the profile (P) are obtained by linking with correction values (Kv) determined according to the movement speed (v) of the solid body (1, 1a).

3. The method according to claim 1 or 2, characterized in that the measured values (Σ _B ) of the profile (P) are obtained by linking with correction values (Ko) determined in accordance with the area of the surface of the solid body (1, 1a).

4. The method according to any one of claims 1 to 3, characterized in that the solid body (1, 1a) carries out a rotating movement.

5. Method according to one of claims 1 to 4, characterized in that the solid body (1, 1a) is a substantially rotationally symmetrical body, in particular a vehicle wheel (1a), and performs a rolling movement.

6. Method according to claim 4 or 5, characterized in that the rotating movement proceeds at a constant angular velocity (ω).

7. The method according to any one of claims 4 to 6, characterized in that the angular velocity (ω) of the rotating movement of the solid body (1, 1a) is less than 15 s ^"1 , preferably less than 6 s ^{" 1} .

8. Method according to claim 3 and one of claims 5 to 7, characterized in that the correction values (Ko) determined according to the area of the surface of the solid body (1, 1a) are vectorial, determined as a function of a radius (R) of the rotationally symmetrical body Factors and / or summands are.

9. Method according to one of claims 1 to 8, characterized in that the correction values (Kv) determined according to the movement speed (v, ω) of the solid (1, 1a) are vectorial factors proportional to the speed of movement (v, ω) and / or summands are.

10. Method according to claim 1, characterized in that for determining the correction values (Kv) determined in accordance with the movement speed (v, ω), a correlative connection of the movement speed (v, ω) with the frequency (f) of the detection of the movement speed reflected light (RL) takes place.

11. The method according to any one of claims 1 to 10, characterized in that a plurality of profilograms (PG) as partial profilograms (PG _a , PGb, PG _C ) using at least three, on different sides of the surface of the solid (1, 1a) lying Areas light bands (3, 3a, 3b, 3c, ed, 3c2, 3c3) projecting laser devices (2) and their associated imaging devices (5) are determined, the Teilprofilogramme (PG _a , PGb, PG _C ) are stored in the data processing system and therefrom a total profilogram (GPG) is obtained.

12. The method according to claim 11, characterized in that in a basic shape in the substantially cylindrical or annular solid (1, 1a), such as a vehicle (1a), the at least three areas on which the light bands (3, 3a, 3b , 3c, 3c1, 3c2, 3c3), on the two top surfaces (Di, D ₂ ) and on the lateral surface (M) of the cylinder or ring lie.

13. The method according to claim 12, characterized in that the overall profile (GPG) of a rolling solid (1, 1a) from three of the two top surfaces (Di, D ₂ ) and on the lateral surface (M) at the same time to a detection time (t _k ) certain Teilprofilogrammen (PG _a, PGB, PG _C) is obtained, wherein the detection time (t _k) of the individual component profilograms (PG _a, PGB, PG _C) is selected such that a for this acquisition time (t _k) determined measured value ( Zk) of at least three on a circular arc with a radius (R) lying in one of the top surfaces (Di, D ₂ ), respectively at successive times (ti, t ₂ , t ₃ ) and unidirectional from the respective length of the line-shaped light band (3, 3a, 3b, 3c, 3c1, 3c2, 3c3) certain measured values (zi, Z ₂ , Z ₃ ), each of which corresponds to half the length of a chord (sh, Sl ₂ , Sl ₃ ) through the arc, assumes a maximum.

14. The method according to claim 1, wherein the profilogram (PG), the partial profilograms (PG ₃ , PG _b , PG _C ) and / or the overall profilogram (GPG) with in each case one or more reference profile (s) (BP1, BP2) are compared and the respective deviations (ΔPG) from the respective reference profile (BP1, BP2) are determined.

15. The method according to any one of claims 1 to 14, dadu rc HGE ke nn i ze et ch n that the profilogram (PG), the component profilograms (PG _a, PGB, PG _C), the overall profilogram (GPG), the respective reference (BP1, BP2) and / or the respective deviations (ΔPG) to a fixed, long-term invariable geometric base size, such as a non-wearing inner rim diameter (2 * R), related.

16. The method according to claim 15, characterized in that the basic size of at least three measured values is determined, which are determined by contactless dynamic measurements on the moving solid (1, 1a), which are made in the same manner as the detection of the profilogram (PG ) or the acquisition of the partial profilograms (PG _a , PGb, PG _C ).

17. The method according to claim 16, characterized in that the non-contact dynamic measurements on the moving solid (1, 1a) at predetermined time intervals (Δt) at least three times (ti, t ₂ , t ₃ ) by means of a single to a linear band of light ( 3, 3a, 3b, 3c, 3c1, 3c2, 3c3) of the expanded light beam.

18. The method according to claim 16, characterized in that the non-contact dynamic measurements on the moving solid at the same time by at least three, each to a line-shaped light band (3, 3a, 3b, 3c, 3c1, 3c2, 3c3) expanded light beams at a predetermined distance (N1 , N2) of the areas of the surface of the solid (1, 1a) onto which the light bands (3, 3a, 3b, 3c, 3c1, 3c2, 3c3) are projected.

19. Method according to claim 15, characterized in that the basic variable is a radius (R) of a rolling rotationally symmetrical body, which is determined from the following system of equations:

R ² = xi ² + zi ² (1)

R ² = X ₂ ² + Z ₂ ² (2)

R ² = X ₃ ² + Z ₃ ² (3)

Xi - X ₂ = k * (x ₂ - X ₃ ) (4),

where Zi, Z ₂ , Z _{3 are} three measured values of the length of the linear band of light (3, 3a, 3b, 3c, 3c1, 3) lying on a circular arc of radius (R), each unidirectionally determined, corresponding to the ordinate (z) of a Cartesian coordinate system. 3c2, 3c3), which correspond in each case to half the length of a chord (sh, Sl ₂ , Sl ₃ ) through the circular arc, xi, X ₂ , X _{3 are} the abscissa values (x) and k associated with these measured values at a predetermined time interval (Δt) or distances (n1, N2) of the areas of the surface of the solid (1, 1a) are corresponding factor.

20. Method according to one of claims 1 to 19, characterized in that the profilogram (PG), the partial profilograms (PG ₃ , PG _b , PG _C ), the overall profilogram (GPG), the respective Reference profile (BP1, BP2) and / or the respective deviations (.DELTA.PG) are visualized in a display device, such as a display.

21. The method according to any one of claims 1 to 20, dad u rch in that as a light receiving element (6) is a digitized signal-supplying device, such as a trigger-controlled CCD camera, is used.

22. The method according to any one of claims 1 to 21, characterized in that as a light receiving element (6), a position-sensitive detector (position sensitive device), such as a photodiode array, is used.

23. The method according to any one of claims 1 to 22, characterized in that the light of the light band (3, 3a, 3b, 3c, 3c1, 3c2, 3c3) has a wavelength in the range of 400 nm to 1000 nm, in particular in the range of 650 to 700 nm.

24. The method according to any one of claims 1 to 23, characterized in that the light of the light band (3, 3a, 3b, 3c, 3c1, 3c2, 3c3) has a wavelength in the visible range and the limit of the accessible radiation (GZS) of Laser device (2) is less than 1 mW.

25. The method according to any one of claims 1 to 24, characterized in that the power of the laser device (2) is in the range of 0.5 to 50 mW.

26. The method according to any one of claims 1 to 25, characterized in that the laser device (2) a cw (continous-wave) -Festkörperdiode, such as one of a semiconductor material such as GaAs, AIGaAs, InGaP, GaAsSb, InP, PbSnTe oa, existing diode, preferably a VLD (visible laser diode) contains.

27. The method according to any one of claims 1 to 26, characterized in that the light band (3, 3a, 3b, 3c, 3c1, 3c2, 3c3) has a width (b) in the range of 0.3 mm to 6.5 mm, in particular in the range of 0.8 mm to 2.2 mm.

28. The method according to any one of claims 1 to 27, characterized in that the light band (3, 3a, 3b, 3c, 3c1, 3c2, 3c3) has a length (LB) in the range of 50 mm to 750 mm, in particular in the range of 200 mm to 400 mm.

29. Method according to one of claims 1 to 28, characterized in that the triangulation angle (φ) has values in the range of 15 ° to 40 °, in particular in the range of 20 ° mm to 30 °, having.

30. The method according to any one of claims 1 to 29, characterized in that the frequency (f), with which of the surface of the solid (1, 1 a) reflected light (RL) by means of the light receiving element (6) is detected in the area from 25 Hz to 100 kHz, preferably in the range of 1 kHz to 10 kHz.

31. Method according to one of claims 1 to 30, in that a translatory movement speed (v) of the solid is less than 3.5 m / s, preferably less than 1.5 m / s.

32. The method according to any one of claims 1 to 31, characterized in that a mean working distance (L) of the laser device (2) and / or the imaging device (5) from the region of the surface of the solid body (1, 1a) on the light band (3, 3a, 3b, 3c, 3c1, 3c2, 3c3) is in the range of 20 mm to 650 mm, in particular in the range of 150 mm to 350 mm.

33. The method according to any one of claims 1 to 32, dadu rch gekennzeich net, that the base distance (B) between the imaging device, (5) in particular the center of a focusing lens (4) of the imaging device (5), and the optical axis (0 -0) of the laser device is in the range of 30 mm to 450 mm, in particular in the range of 60 mm to 270 mm.

34. The method according to any one of claims 1 to 33, dadu rch in that for the profilogram (PG), the partial profilograms (PG ₃ , PG _b , PG _C ), the overall profile (GPG), the respective reference profile (BP1, BP2) and / or the respective deviations (ΔPG) is based on a resolution (dzA) of less than 2.0 mm, in particular less than 0.5 mm.

35. The method according to claim 1, wherein a hardware component is incorporated in a test stand (8) located on a track (9) in order to realize the recording loop (100).

36. The method of claim 1, wherein the recording loop is implemented in a client-server circuit with a remote server, wherein system boot processes (95), such as a Control of a traffic light for a rail vehicle (10), the activation of a trigger for image triggering (106A, 106B, 106C) and / or switching on the laser device (2), by request (90) set by the server in motion.

37. Method according to claim 1, wherein a signal, in particular a distance signal, is provided in the recording loop by a laser distance sensor after signal conditioning from which a signal evaluation (104) initiators (105A, 105B, 105C) for the image triggering (106A, 106B, 106C) are obtained.

38. The method according to claim 37, characterized in that by the signal evaluation (104) between the distance signal (103) and the initiators (105A, 105B, 105C) for the image triggering (106A, 106B , 106C) by means of a programmable device (PLD), which allows to configure different time-based logical sequences, predetermined logical and temporal links are established.

39. Method according to claim 1, characterized in that image matrices (107A, 107B, 107C) are provided by the image triggering (106A, 106B, 106C), which in a, preferably cyclically operating, sequential image memory of the light receiving element (6 ) are cached.

40. The method according to claim 39, characterized in that from the image matrices (107A, 107B, 107C), in particular as a function of the velocity (v) of the solid body (1, 1a), an image selection (IS) of one of the measured values (Z _B ) of the profile (P) representative image matrix (107) takes place.

41. Method according to claim 36, characterized in that after obtaining the measured values (Z _B ) of the profile (P), in particular after stopping (112) the image recording, the measured values (z _B ), in particular stored image data (108), preferably together with the respectively associated values of a distance from the laser device (2), a measuring location corresponding to a used light band (3c1, 3c2, 3c3) and / or a time (ti, t _2, t ₃ ) of the image triggering ( 106A, 106B, 106C) are sent to the server (113).

42. Method according to claim 1, characterized in that the recording loop (100) contains condition checks (110, 111) bound to a timer and / or to a number of predetermined measurements as termination criteria.