WO2008131722A1

WO2008131722A1 - Ultrasound measuring system

Info

Publication number: WO2008131722A1
Application number: PCT/DE2008/000644
Authority: WO
Inventors: Björn Diewel; Reinhold Oster
Original assignee: Eurocopter Deutschland Gmbh
Priority date: 2007-04-25
Filing date: 2008-04-14
Publication date: 2008-11-06
Also published as: DE102007019764A1

Abstract

The invention relates to an ultrasound measuring system (1), comprising an ultrasound probe (4) that can be freely guided by hand and that interacts with an ultrasound measuring device (3), for destruction-free material testing by the analysis of an ultrasound image. According to the invention, a plurality of distance sensors (9, 10) is provided, following the movements of the ultrasound probe (4) such that the coordinates of the ultrasound probe (4) are determined and can be associated with the respective measurement result by the ultrasound measuring device (3).

Description

ULTRASONIC HAND MEASURING SYSTEM WITH POSITIONING DETERMINATION

The invention relates to an ultrasound measuring system according to the preamble of claim 1 and to a method for ultrasound imaging with an ultrasound measuring system according to claim 11.

Such ultrasonic measuring systems are known in various embodiments and are used for non-destructive material testing. They are used in quality control as well as for the continuous inspection of materials, in particular fiber composites, but also in metal components. Quality control of fiber composites is primarily concerned with finding production defects, shrinkage cracks, blowholes, porosities, foreign inclusions, delaminations, etc.

In the inspection, you can find errors or damage caused, for example, by external influences - impacts etc.

It is known that a hand-held ultrasonic test head is manually guided by a tester designed for this purpose over the component or the affected region. The measuring point can be marked with colored pencils on the measuring point of the surface of the material to be tested. However, a reproducible documentation is not possible because only one online measurement is performed using the A-image display evaluated by the examiner.

By means of the ultrasonic measuring system, such errors can be determined. In this case, the ultrasound data, which is referred to as a so-called A-image, always only the state at exactly the position at which the probe is located at that moment. If one now places the information from the A-pictures flat next to each other, exactly at the point where it was detected, then one has a geometrically accurate representation of the point of damage. The result is an ultrasound imaging. From this, further images of the measuring range and thus of the material being examined can be generated, for example the measurement result based on a cross section through the material or in a spatial representation. These representations are known as B, C and D pictures.

So that the measurement result can be assigned to specific measurement points and the images just described can be generated, it is necessary to capture the coordinates of the measurement point in a predetermined measurement range for the measurement.

Ultrasonic measuring systems are known in which the ultrasonic probe having an ultrasonic sensor is guided in the manner of a plotter with X and Y arms over the surface to be tested. However, this guidance is actively performed and the examiner does not have the option of manual, chaotic guidance by hand.

A disadvantage of this known ultrasonic measuring system is that it is very complicated and expensive on the one hand. The construction is very complex and heavy. On the other hand, the known ultrasound measuring system is cumbersome to transport and in particular expensive to mount on the test object, resulting in high set-up times.

The invention is based on the object to provide an ultrasonic measuring system, on the one hand has a simple structure and on the other hand can be easily assembled. In addition, a documentation of the measured data should be readily possible.

This object is achieved by an ultrasonic measuring system according to claim 1.

The invention is based on the finding that not as previously the ultrasonic probe is guided over a coordinate measuring system, over which the spatial assignment of the measurement results to the measurement points, but that the ultrasonic probe is guided by hand freely and this movement tracked by transducer / transducer and above the coordinates of the measuring points are determined. This eliminates the need for expensive structures for guiding the ultrasonic probe and it results in a simple construction, which also also can be easily assembled. The guidance of the ultrasonic probe is thus separated from the determination of the coordinates. By means of suitable interfaces, the measured data can then be easily associated with the coordinates, graphically processed and simply displayed via a display unit, for example a display. This allows a repeatable, reproducible measurement in a simple manner, which also allows documentation and logging of the measurement process without major additional measures. Every third person can repeat the measurement and then get the same results.

By means of the ultrasonic measuring system according to the invention, a measurement of certain critical parts can thus be carried out on site at a customer or, for example, in the case of an aircraft on the airfield.

In this case, the ultrasound probe, which comprises the ultrasound sensor, is guided by hand, wherein a "chaotic" guidance of the ultrasound probe is also possible, in particular by tracking the free sensor position, ie the respective position of the ultrasound probe, by the displacement transducers. This makes it possible to detect both small and relatively large measuring surfaces in an advantageous manner.Also, measurements on curved surfaces are possible, the latter being possible because only two-dimensional position detection is carried out.Thus, a three-dimensional test object appears only slightly distorted - in the projection or Settlement - so that this has no significant impact on the measurement result.

The invention can be as mentioned above perform a test with a hand-held ultrasonic measuring system and still has the advantage that the Measurement data of the ultrasonic probe the coordinates can be assigned. This allows the result to be easily visualized. The already mentioned C, B and D pictures can be easily generated. Not only a reproducibility of the measurement, but above all a simple documentation is possible. This is a decisive advantage especially in the aerospace industry, but also in any other industry, as here vulnerable parts must be checked regularly in predetermined inspection cycles.

According to an advantageous development of the ultrasonic measuring system according to the invention, it is provided that two displacement transducers together with the ultrasonic sensor / test head form a triangular arrangement. The distance of the displacement sensor to each other forms a constant base length of a base side of a triangle. The distance of the first transducer to the ultrasonic probe forms a first length of a first side of the triangle and the distance of the second transducer to the ultrasonic probe forms a second length of a second side of the triangle. The coordinates of the ultrasonic probe can be calculated with the help of the mentioned lengths. Alternatively, an angle is calculated which extends between the first side of the triangle and the base side or between the second side and the base side.

For this purpose, preferably two Seilzugwegaufnehmer be mounted on a surface. The distance between these transducers forms the base of a triangle, with the two cables of the transducers forming the legs of the triangle. Thus, one can determine, in a mathematically quite simple way, the X- and Y-coordinates of the ultrasonic probe and thus of the measuring point on the surface of the object to be measured. This preferred solution is characterized by low cost and an almost arbitrary position of Seilzugwegaufnehmer. In addition, any guidance of the ultrasonic probe with the ultrasonic sensor can be selected on the component or object to be measured.

Conveniently, the transducers can be considered incremental Seilzugwegaufnehmer, or be designed as an analog Seilzugwegaufnehmer.

In order to be able to display a plurality of images in a simple manner, it is provided in a preferred manner that both displacement transducers are connected to a computer and also the ultrasound test head is connected to this computer. As a result, digitalized measurement data are delivered to the computer so that the computer can calculate an overall image and display it via an indicator.

According to a preferred method for ultrasound imaging with the ultrasonic measuring device according to the invention, the Cartesian X and Y coordinates of the ultrasonic test head are simply calculated via trigonometric functions in the triangle. The lengths of the legs of the triangle required for this purpose are determined by means of the displacement transducer. The base length of the triangle, the distance of the transducer to each other, is given as a constant for each measurement.

The data obtained during the measurement with the measuring system according to the invention are easily electronically logged, so that a documentation, as it is often required in industry, is possible.

Conceivable, however, are other applications that require easy installation of the ultrasonic measuring system on site and their documentation, for example in shipbuilding. In general, the ultrasonic measuring system is easy to transport and therefore very flexible.

As mentioned above, the Cartesian X and Y coordinates of the ultrasonic probe can be calculated using an angle in the triangle and corresponding angle functions. In this case, the respective X and Y coordinates over the first length of the first page and / or the second length of the second page and the base can be calculated using the following formulas: α = arccos ((L _b ^z + L _c ² - L ₃ ² ) / (2 * L _b * L ₀ )),

X = L ₃ * cos α,

Y = L ₃ * sin α.

Where L _{3 is} the length of the first side of the triangle, L _{b is} the length of the second side of the triangle, L _{0 is} the length of the base side of the triangle, and α is the angle between the first side and the base side.

During a test procedure, the ultrasonic test head can be guided both by an undefined movement, in particular a chaotic hand guide, as well as by a defined, in particular a meander-shaped hand guide.

Preferably, the ultrasonic measuring system is used in aerospace.

The inventive method has been described using the example of a single ultrasonic probe. But it is also possible to use a probe with multiple ultrasonic sensors instead of a single ultrasonic probe with an ultrasonic sensor. In this case, a plurality of ultrasonic sensors line or line-shaped side by side in the form of a Zeilenbzw. Line arrays (line probe) or distributed over a surface in the form of a surface array (surface probe) may be arranged.

Further advantageous developments of the invention are described in the subclaims.

An embodiment will be explained in more detail with reference to the drawings, wherein further advantageous developments of the invention and advantages thereof are described. Show it: 1 is a block diagram of a preferred embodiment of the ultrasonic measuring system according to the invention;

FIG. 2 shows a representation of the test head and position transducer arrangement with X and Y coordinates as well as a triangular angle α; FIG.

3 shows a two-dimensional representation of a displacement transducer;

FIG. 4 shows a further two-dimensional representation of the displacement transducer shown in FIG. 3; FIG.

5 is an illustration of the Prüfkopf- / Wegaufnehmeranordung with a meandering manual guide of the test head.

Fig. 6 is a C image of an impact in carbon fiber;

FIG. 7 shows a B image of an impact in carbon fiber, and FIG

8 shows an A-image of an ultrasound measurement.

1 shows an embodiment of the ultrasound measuring system 1 according to the invention. This comprises a hand ultrasound measuring device 3 and a freely movable, manually guided ultrasound sensor having a test head 4. The test head 4 is connected to the hand ultrasound measuring device 3 with a connecting cable 5, wherein the cable 5 transmits the ultrasonic measurement signal. The hand ultrasound measuring device 3 is connected to a computer 6. This receives digitized measurement data of the hand-held ultrasonic measuring device 3 with the help of another connecting line. 7

The housing of the test head 4 is expediently designed so that the test head 4 can be easily guided over the component to be tested by hand. The computer 6 is preferably designed as a PC, in particular as a portable PC or laptop, but may also be integrated into the ultrasonic measuring system 1. At this two transducers 9 and 10 are connected. The first displacement transducer 9 is at a distance from the second displacement transducer 10. The distance between the first displacement transducer 9 and the second displacement transducer 10 is basically variably adjustable and is communicated to the software via corresponding input means, so that it can be taken into account in the calculation. During the measurement, however, the distance is constant.

The displacement sensors 9 and 10 are preferably designed as cable pull receivers each having a cable 11, 12. Both ropes 11 and 12 are connected to the test head 4, as illustrated in FIG.

The test head 4 is freely movable, as long as a limited cable length of the transducer 9 and 10 is not exceeded.

As FIG. 1 shows, the two transducers, namely the transducers 9 and 10, are arranged in triangular fashion together with the test head 4. The distance between the displacement sensor 9 and 10 to each other corresponds to a base length L _c and forms a side c of a triangle whose vertices are formed by the probe 4 and the Wegaufnehmem 9 and 10, as shown in FIG. The base length L _c is freely selectable within certain limits. The distance of the first displacement transducer 9 to the test head 4 corresponds to a length L _{3 of} a side a of the triangle. The distance of the second displacement transducer 10 to the test head 4 corresponds to a length Lb of a side b of the triangle. With the aid of the lengths L _a , L _b and L ₀ , the X and Y coordinates of the test head 4 can be easily calculated, as will be explained below:

First, an angle α is calculated, which extends between the first side a and the side c of the triangle. α = arccos ((L _b ² + L _c ² - L ₃ ² ) / (2 * L _b * L ₀ )).

With the polar coordinates (L ₃ ; α), the Cartesian coordinates X, Y of the test head 4 can then be calculated according to the following formulas:

X = L ₃ * cos α, Y = L ₃ * sin α,

Similarly, the Cartesian coordinates can also be calculated using the angle between page b and page c.

The transducers 9 and 10 in the form of cable pullers are commercially available position sensors, for example incremental cable pull receivers. The rope length can be changed, for example, between 120 mm and 1250 mm. At the free end of the rope there is preferably a cable clip 15 which serves for attachment to the test head 4 (see FIG. 4).

The displacement sensor 9, 10 according to FIG. 3 or 4 is further provided with a receiving housing 16. In this case 16, the retracted rope 11 is rolled up. A cable drum located in the housing 16 is rotatably disposed in the housing 16. A rotation of the drum or an angular change is detected in a known manner.

Both incremental-digital displacement transducers and analog transducers for the ultrasonic measuring system 1 can be used.

In the digital variant, the output signal corresponds to 5 to 10 pulses per mm of elongation or, in the case of the analog version, 0 to 10 V to the entire cable length.

In an analog version A / D interfaces are provided to allow a connection to the computer 6. The displacement sensors 9 and 10 can be fastened with a screw fastening on the measuring field or else with other fixing means, such as a suction cup, magnet, double-sided adhesive tape or the like. This allows a relatively free positioning on the measuring field to be tested.

Preferably, a total pitch of 25 to 2500 mm, in particular from 250 to 1250 mm provided, larger lengths are of course also possible, so that considerably larger test objects can be detected. This is possible because no special frame construction is required.

Expediently, in a measurement, the test head 4 is guided meander-shaped over a test object, as illustrated in FIG. 5. Reference numeral 17 denotes the meandering shape.

FIGS. 6 to 8 show images which show, by way of example, measurements which the measuring system 1 according to the invention generates. Thus, both C-pictures as shown in Fig. 6 and B-pictures as shown in Fig. 7 are possible.

With the arrangement shown, a relatively high measurement accuracy can be achieved. In the following, a coordinate recording using the hand ultrasound measuring device 3 and the cable pull receiver, as a displacement transducer 9, 10 is explained in more detail.

First, the analog signals of the transducers are output via an A / D interface. This can be an interface for connection to a laptop or notebook or be implemented directly in the ultrasound measuring system 1.

In a second step, a scaling of an analog signal takes place, wherein, for example, 10 V corresponds to a cable length of 250 mm. In a next step, the measured signals are digitized. The base length L _C) so the distance between the two transducers 9 and 10 can be entered for example by means of a manual controller. Alternatively, the base length L _{0 can} also be entered using a PC keyboard or notebook keyboard. If the cable length values L ₃ , U and the base length L _c are stored in the computer 6, these are used for the above-mentioned calculation of the polar coordinate α and the subsequent calculation of the Cartesian coordinates X, Y of the test head 4.

In addition, a module for recording or storing the measured numerical values is provided. A measurement image formed from these numerical values can be represented by means of a monitor or a printer 20, see FIG. 1.

In order to prevent a too large measurement error results when the angle α is too small, it is provided that at a too small angle α simply a value 0 appears on a display, so that the angle α is triggered.

The solution shown is especially suitable for scanning on non-planar surfaces. In a curved surface, a plan view is generated by the computer 6. The three-dimensional surface is thus projected onto a two-dimensional plane. For the measuring method with the guidance of the test head 4 in space results in the described system - two-dimensional scanning - a negligible coordinate error.

The invention is not limited to the embodiments shown, but also includes comparable solutions. For example, the transducers 9 and 10 can also be embodied as other displacement sensors. The aim of the invention is to guide the test head 4 free. In addition to the described transducers but also other coordinate tracking systems are conceivable, for example, a laser tracker. In this case, a laser beam from the corner points of the base side of the triangle would be directed to the test head 4, the at this embodiment has mirrors. The lasers track the mirrors. The coordinates of the test head 4 can then be calculated analogously to the formulas described above.

Also, another optical system is conceivable, for example in the form of video heads, which form the transducers. The video heads track the movement of the probe 4 and determine its coordinates analogous to the photogrammetry.

Decisive in the invention is that the test head 4 can be guided freely by hand and a coordinate measuring system tracks the movement of the test head 4.

The measurement results can then be easily converted into coordinates of the test head 4, stored and further processed. The image representations known from ultrasonic measurement technology, for example the A-BiId, an ultrasound measurement, as shown in FIG. 8, can now easily be converted into a B-type, C-type or D-type image, although a chaotic one Measurement of the test area is done via the hand guide.

The transducers 9, 10 can be easily transported. The entire ultrasonic measuring system 1 according to the invention is lightweight and therefore also directly on site on the objects to be tested, without having to bring these objects in a laboratory. A preferred field of application is aerospace engineering, where material controls must be performed on a regular basis and in particular a continuous documentation of these controls is required. LIST OF REFERENCE NUMBERS

I Ultrasonic measuring system 3 Hand ultrasonic measuring device

4 test head

5 connection cable

6 computers

7 connecting line 9 transducer

10 transducers

I 1 rope 12 rope

15 cable clip 16 housing

17 Meander shape of the track of the test head

20 Printer α Angle / Polar Coordinate

L _a Length of the first side of the triangle L _b Length of the second side of the triangle

L ₀ length of the base side of the triangle c base side of the triangle a first side of the triangle b second side of the triangle

Claims

claims

1. Ultrasonic measuring system (1), with a hand freely executable ultrasonic probe (4), which cooperates with an ultrasonic measuring device (3) for non-destructive material testing on the analysis of an ultrasound image, characterized in that a plurality of displacement sensors (9, 10) are provided are, which track the movement of the Ultraschallprüfkopfes (4) and determine the coordinates of the ultrasonic probe (4), which are assigned by the ultrasonic measuring device (3) the respective measurement result.

2. Ultrasonic measuring system according to claim 1, characterized in that the displacement transducer (9, 10), the distance between the ultrasonic probe (4) and the respective displacement transducer (9, 10) detect, wherein the

Position transducer (9, 10) are arranged such that at least on the basis of the distance between the ultrasonic probe (4) and the displacement sensors (9, 10) is a two-dimensional spatial position of the ultrasonic probe (4) can be calculated.

3. Ultrasonic measuring system according to claim 1 or 2, characterized in that the displacement transducer (9, 10) and the ultrasonic probe (4) form a triangular arrangement, wherein the distance of the displacement transducer (9, 10) to each other a constant base length (L _c ) one side (c) of a triangle, the distance of the first displacement transducer (9) to the

Ultrasonic probe (4) a first length (L _a) a first side (a) of the triangle and the distance of the second transducer (10) for ultrasonic probe (4) a second length (L _b) a second side (b) of the triangle forms, so that the coordinates of the ultrasonic probe (4) can be calculated by the lengths (L _a , Lb, L _c ).

4. Ultrasonic measuring system according to one of the preceding claims, characterized in that the displacement sensor as a cable pull receiver (9, 10) are executed.

5. Ultrasonic measuring system according to claim 4, characterized in that the Seilzugaufnehmer (9, 10) are equipped with a Präzisionspotenziometer for detecting a Abwicklungslänge, wherein they provide an analog output signal, in particular 0 to 10 V.

6. Ultrasonic measuring system according to claim 4 or 5, characterized in that the displacement transducer (9, 10) has a pitch of 25 to 2500 mm, in particular from 250 to 1250 mm.

7. Ultrasonic measuring system according to one of the preceding claims, characterized in that the displacement transducer (9, 10) as

Incremental pulse encoders, in particular with 5 to 10 pulses per mm change in length, are executed.

8. Ultrasonic measuring system according to one of the preceding claims, characterized in that the displacement transducer (9, 10), in particular via A / D interfaces, to a computer (6) are coupled and the Ultraschallprüfkopf (4) via the ultrasonic measuring device (3 ) is connected to the computer (6) to transmit digitized measurement data to the computer (6), so that the computer (6) can calculate an ultrasound image composed of a plurality of measurements.

9. Ultrasonic measuring system according to one of the preceding claims, characterized in that the displacement transducers (9, 10) each have at least one fixing means for their free positioning on a surface of a component to be tested.

10. Ultrasonic measuring system according to one of the preceding claims, characterized in that the Ultraschallprüfkopf (4) is designed as a single probe, line probe or Flächenprüfkopf.

11. A method for ultrasound imaging with an ultrasonic measuring system (1) according to any one of the preceding claims, characterized in that Cartesian X and Y coordinates of the Ultraschallprüfkopfes (4) by means of an angle (α) in the triangle and over sin, cos , aresin and / or arecos relationships are calculated.

12. The method according to claim 11, characterized in that the X and Y coordinates based on the first length (l_ _a), the second length (Lb) and the base length (L ₀₎ of the triangle are calculated according to the following formulas: X = L _a * cos α,

Y = L _a * sin α, α = arecos ((L _b ² + L ₀ ² - L ₃ ² ) / (2 * L _b * L ₀ )).

13. A method, in particular according to claim 11 or 12, for ultrasound imaging with an ultrasonic measuring system (1) according to one of claims 1 to 10, characterized in that the Ultraschallprüfkopf (4) by an undefined movement, in particular a chaotic hand guide and / or by a defined, in particular a meander-shaped hand guide (17) is guided.

14. Use of an ultrasonic measuring system (1) according to one of the preceding claims in aerospace.