DE4437205A1 - Ultrasonic displacement measuring unit consisting of ultrasonic transmitter and receiver - Google Patents
Ultrasonic displacement measuring unit consisting of ultrasonic transmitter and receiverInfo
- Publication number
- DE4437205A1 DE4437205A1 DE19944437205 DE4437205A DE4437205A1 DE 4437205 A1 DE4437205 A1 DE 4437205A1 DE 19944437205 DE19944437205 DE 19944437205 DE 4437205 A DE4437205 A DE 4437205A DE 4437205 A1 DE4437205 A1 DE 4437205A1
- Authority
- DE
- Germany
- Prior art keywords
- signal
- transmitter
- ultrasonic
- receiver
- measurement
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
Links
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01B17/00—Measuring arrangements characterised by the use of infrasonic, sonic or ultrasonic vibrations
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S15/00—Systems using the reflection or reradiation of acoustic waves, e.g. sonar systems
- G01S15/02—Systems using the reflection or reradiation of acoustic waves, e.g. sonar systems using reflection of acoustic waves
- G01S15/06—Systems determining the position data of a target
- G01S15/08—Systems for measuring distance only
- G01S15/10—Systems for measuring distance only using transmission of interrupted, pulse-modulated waves
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S15/00—Systems using the reflection or reradiation of acoustic waves, e.g. sonar systems
- G01S15/02—Systems using the reflection or reradiation of acoustic waves, e.g. sonar systems using reflection of acoustic waves
- G01S15/06—Systems determining the position data of a target
- G01S15/08—Systems for measuring distance only
- G01S15/32—Systems for measuring distance only using transmission of continuous waves, whether amplitude-, frequency-, or phase-modulated, or unmodulated
- G01S15/36—Systems for measuring distance only using transmission of continuous waves, whether amplitude-, frequency-, or phase-modulated, or unmodulated with phase comparison between the received signal and the contemporaneously transmitted signal
Landscapes
- Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- Radar, Positioning & Navigation (AREA)
- Remote Sensing (AREA)
- General Physics & Mathematics (AREA)
- Acoustics & Sound (AREA)
- Computer Networks & Wireless Communication (AREA)
- Measurement Of Velocity Or Position Using Acoustic Or Ultrasonic Waves (AREA)
- Length Measuring Devices Characterised By Use Of Acoustic Means (AREA)
Abstract
Description
Ultraschall-Meßverfahren sind heute gängige Verfahren in der Längenmeßtechnik. Es sind in der Praxis zwei Methoden bekannt: Das Impuls-Echo - Verfahren, nach dem ein Schallpaket ausgesandt und von einem anderen oder demselben Wandler aufgenommen wird und die Laufzeit des Schallpakets ermittelt wird.Ultrasonic measuring methods are now common methods in length measurement technology. It is in two methods are known in practice: the impulse-echo method, according to which a sound package sent out and recorded by another or the same converter and the Running time of the sound package is determined.
Ein anderes Verfahren arbeitet im Dauerstrichbetrieb. Ein Schallsender sendet durchgehend eine Schallwelle ab. Ein Empfänger nimmt diese auf, der Vergleich der Phasenlage zwischen Sender- und Empfängersignal gestattet nun einen Rückschluß auf eine Wegänderung. Das erste Verfahren mißt absolut, jedoch ungenau, weil nur schwierig auf Bruchteile von einer Wellenlänge gemessen werden kann, besteht doch das Pulspaket selbst nur aus wenigen Schallwellen. Das zweite Verfahren ist hingegen sehr genau, da über einen Phasendiskriminator sehr kleine Bruchteile einer Wellenlänge aufgelöst werden kann, jedoch wiederholen sich die Phasenlagen periodisch, die Messung ist also nicht absolut, es werden nur Wegunterschiede gemessen.Another method works in continuous wave mode. A sound transmitter transmits continuously a sound wave. A receiver records this, comparing the phase position between The transmitter and receiver signals now allow conclusions to be drawn about a change in route. The first method measures absolutely but imprecisely because it is difficult to measure a fraction of one Wavelength can be measured, since the pulse package itself consists of only a few Sound waves. The second method, on the other hand, is very precise because it uses one Phase discriminator can resolve very small fractions of a wavelength, however the phase positions are repeated periodically, so the measurement is not absolute, it will only be Path differences measured.
In den Einschränkung: Ungenau und absolut bzw. genau und relativ liegen die Grenzen der Schall - Entfernungsmessung. Auch die Temperaturkompensation ist eine wichtig zu nehmende Einschränkung des Verfahrens, da die Schallgeschwindigkeit mit der Wurzel aus der Temperatur zunimmt und dadurch eine Fehlerquelle gegeben ist.In the restriction: imprecise and absolute or exact and relative are the limits of Sound distance measurement. Temperature compensation is also important Limiting process because the speed of sound with the root out the temperature increases and there is a source of error.
Weiterhin setzt das Impulsecho - Verfahren voraus, daß ein relativ starker Impuls vorhanden ist, um den Schallwandler anzuregen. Das Dauerstrichverfahren hingegen hat den Vorteil, daß bei geringerer Erregerspannung des Senders eine Signalübertragung möglich ist, weil Sender und Empfänger durchgängig in Eigenresonanz schwingen können. Ein weiterer Nachteil des Impuls-Echo - Verfahrens liegt darin, daß durch die endliche Länge des Schallpakets erst ab einem Grundabstand gemessen werden kann.Furthermore, the pulse echo method requires a relatively strong pulse to be present is to excite the transducer. The continuous wave method, however, has the advantage that with a lower excitation voltage of the transmitter, a signal transmission is possible because the transmitter and receiver can vibrate throughout in self-resonance. Another disadvantage of Pulse-echo - the process is based on the finite length of the sound package a basic distance can be measured.
Das vorgeschlagene Verfahren ermöglicht es, zunächst im Dauerstrich zu arbeiten, wobei ein günstiges Verhältnis von Senderspannung zu Schallsignalhöhe erzeugt wird. Die Genauigkeit des Phasenvergleichverfahrens kann mit der Absolutmessung durch das modulierte Signal kombiniert werden, weiterhin wird durch die nun gewonnene Genauigkeitserhöhung auch eine sehr viel bessere Temperaturkompensation möglich. Zusätzlich erniedrigt sich der erzielbare Mindestabstand für die Abstandsmessung.The proposed method makes it possible to work first in a continuous line, with a favorable ratio of transmitter voltage to sound signal level is generated. The precision the phase comparison method can be carried out with the absolute measurement by the modulated signal be combined, furthermore, due to the now increased accuracy, also one much better temperature compensation possible. In addition, the achievable decreases Minimum distance for the distance measurement.
Die Erfindung ist im folgenden anhand schematischer Zeichnungen an Ausführungsbeispielen mit weiteren Einzelheiten näher erläutert. Es zeigt:The invention is based on schematic drawings of exemplary embodiments explained in more detail with further details. It shows:
Fig. 1 im Blockschaltbild eine grundsätzliche Schaltungsmöglichkeit;1 shows a basic circuit possibility in the block diagram;
Fig. 2 im Blockschaltbild eine Ausführungsform mit digitaler Modulation des Trägersignals; Fig. 2 is a block diagram showing an embodiment with digital modulation of the carrier signal;
Fig. 3 die Anordnung im Reflexionsbetrieb. Fig. 3 shows the arrangement in reflection mode.
Eine Darstellung ist aus Fig. 1 ersichtlich. Ein Generator 2 erzeugt, um die Schallabstrahlung zu optimieren, ein Signal in der mechanischen Eigenresonanz des Ultraschallsenders 1. Das Signal wird dem Wandler von einem Modulationsgenerator 8 über einen Modulator 3 zugeführt. Hierdurch erhält der Wandler zusätzlich noch ein Modulationssignal, so daß er Schwingungen mit einem trägermodulierten Signal ausführt. Ein Empfänger 4 nimmt das Signal auf, es wird in einem Demodulator 5 in seine Bestandteile, in den Träger und das modulierte Signal zerlegt und danach beide Signale in den Vergleichern 6 und 7 mit den ursprünglichen Signalen bezüglich ihrer Phasenlage und/oder Laufzeit verglichen. An illustration is shown in FIG. 1. In order to optimize the sound radiation, a generator 2 generates a signal in the mechanical natural resonance of the ultrasound transmitter 1 . The signal is fed to the converter from a modulation generator 8 via a modulator 3 . As a result, the converter also receives a modulation signal so that it carries out vibrations with a carrier-modulated signal. A receiver 4 receives the signal, it is broken down into its components, the carrier and the modulated signal in a demodulator 5 and then both signals in the comparators 6 and 7 are compared with the original signals with regard to their phase position and / or transit time.
Die absolute Anzeige soll dabei so genau sein, daß eine additive Darstellung über die Feinanzeige durch Phasenvergleich möglich ist.The absolute display should be so precise that an additive representation of the Fine display by phase comparison is possible.
Allgemeine Funktionsbausteine wie Signalverstärker sind hier nicht gezeichnet, da sie jedem Fachmann selbstverständlich sind.General function blocks such as signal amplifiers are not shown here because they are used by everyone Expert are self-evident.
Eine weitere Konkretisierung ist aus Fig. 2 ersichtlich:
Hier ist gezeigt, wie durch Kreuzkorrelation trotz der Komplexität des Verfahrens eine
preiswerte Lösung zu realisieren ist:
Wieder sind vorhanden Sender 1 und Empfänger 2, ein Modulator 3, ein Demodulator 4 und
ein Ultraschallgenerator 5, der auf die Sendereigenfrequenz abgestimmt ist. Nun wird digital
ein PRN-Signal 6 (Periodic random noise) erzeugt, was digital ohne großen Aufwand über ein
Schieberegister oder einen Mikrokontroller möglich ist. Um nun zur Korrelationsfunktion zu
gelangen, müssen die beiden Signale, das ursprüngliche und das demodulierte miteinander
multipliziert und zeitlich gemittelt werden, dies für verschiedene Zeitverzögerungen zwischen
beiden Signalen. Vorteilhaft und kostengünstig läßt sich dies so realisieren, daß das
PRN-Signal digital verzögert 7, dann multipliziert wird 8, und schließlich ein Regler 9 die
Zeitverzögerung so einstellt, daß jeweils das Optimum des Korrelogramms eingeregelt wird
und sich somit immer der gewünschte Meßwert einstellt. Wie bereits dargestellt, wird der
Phasendiskriminator 10 für die Feinmessung genutzt.A further specification can be seen in FIG. 2:
Here is shown how an inexpensive solution can be achieved through cross-correlation despite the complexity of the method:
Again there are transmitter 1 and receiver 2 , a modulator 3 , a demodulator 4 and an ultrasound generator 5 which is tuned to the transmitter natural frequency. A PRN signal 6 (periodic random noise) is now generated digitally, which is possible digitally without great effort using a shift register or a microcontroller. In order to arrive at the correlation function, the two signals, the original and the demodulated one, have to be multiplied and time-averaged, this for different time delays between the two signals. This can be realized advantageously and inexpensively in such a way that the PRN signal is digitally delayed 7 , then multiplied 8 , and finally a controller 9 sets the time delay in such a way that the optimum of the correlogram is adjusted in each case and thus the desired measured value is always set. As already shown, the phase discriminator 10 is used for the fine measurement.
In Fig. 3 ist außerdem dargestellt, daß das Verfahren auch im Reflexionsbetrieb arbeiten kann. Hier besteht auch die Möglichkeit, über ein Hindernis 1, dessen Abstand von Sender 2 und Empfänger 3 sehr genau bekannt ist, eine Temperaturkompensation herzustellen, deren Genauigkeit entsprechend der eigentlichen Messung sehr hoch ist.In Fig. 3 is shown furthermore that the process can also operate in reflection mode. Here there is also the possibility of producing a temperature compensation via an obstacle 1 , the distance of which from the transmitter 2 and receiver 3 is very precisely known, the accuracy of which is very high according to the actual measurement.
Nicht eingezeichnet ist die Möglichkeit der Genauigkeitsverbesserung, indem entsprechend Fig. 1 sowohl Sendersignal 2 und Trägersignal am Empfänger 4 phasenstarr, z. B. durch eine Phase - locked - loop - Schaltung multipliziert und dann die Phasenlage des höherfrequenten Signals in 7 ausgewertet wird.The possibility of improving the accuracy is not shown, in that, according to FIG. 1, both the transmitter signal 2 and the carrier signal at the receiver 4 are phase-locked, e.g. B. multiplied by a phase-locked-loop circuit and then the phase position of the higher-frequency signal in 7 is evaluated.
Claims (5)
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DE19944437205 DE4437205A1 (en) | 1994-10-18 | 1994-10-18 | Ultrasonic displacement measuring unit consisting of ultrasonic transmitter and receiver |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DE19944437205 DE4437205A1 (en) | 1994-10-18 | 1994-10-18 | Ultrasonic displacement measuring unit consisting of ultrasonic transmitter and receiver |
Publications (1)
Publication Number | Publication Date |
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DE4437205A1 true DE4437205A1 (en) | 1996-04-25 |
Family
ID=6531070
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
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DE19944437205 Withdrawn DE4437205A1 (en) | 1994-10-18 | 1994-10-18 | Ultrasonic displacement measuring unit consisting of ultrasonic transmitter and receiver |
Country Status (1)
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DE (1) | DE4437205A1 (en) |
Cited By (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0969292A2 (en) * | 1998-06-30 | 2000-01-05 | Subacoustech Limited | Distance measuring systems, altimeters and aircraft |
DE19841154A1 (en) * | 1998-09-09 | 2000-04-06 | Holger Loehmer | Measurement of propagation time of sound waves; involves measuring phase shift between transmitted and received signals at two different frequencies |
DE19628849C2 (en) * | 1996-07-17 | 2002-10-17 | Eads Deutschland Gmbh | Acoustic directional emitter through modulated ultrasound |
DE10142364A1 (en) * | 2001-08-30 | 2003-04-03 | Advanced Acoustix Gmbh | Determination of the distance to a soft sound object, whereby measurements are made at two or more different frequencies so that a material dependent phase correction can be made |
WO2005019858A1 (en) * | 2003-08-26 | 2005-03-03 | David Antony Crellin | A method of and apparatus for measuring a change in distance between two locations |
DE102007060346A1 (en) * | 2007-12-14 | 2009-06-18 | Hochschule Offenburg | Delay measuring method for two dimensional or three dimensional-positioning of objects, involves evaluating correlation signal according to magnitude and phase for determining delay of ultrasonic pulse at transmission path |
DE102011004830A1 (en) | 2011-02-28 | 2012-08-30 | Holger Löhmer | Method for measuring propagation velocity of sound waves in e.g. liquid medium, involves determining approximation of propagation velocity of sound waves in measuring section based on phase angles of sound waves |
Citations (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2253975A (en) * | 1938-09-26 | 1941-08-26 | Radio Patents Corp | Distance determining system |
US3433058A (en) * | 1966-05-04 | 1969-03-18 | United Eng Foundry Co | Acoustic flatness measurement device |
US4054862A (en) * | 1975-10-28 | 1977-10-18 | Raytheon Company | Ranging system with resolution of correlator ambiguities |
GB1533630A (en) * | 1975-09-22 | 1978-11-29 | Eastman Kodak Co | Sheet detecting method and apparatus |
GB2121174A (en) * | 1982-05-20 | 1983-12-14 | Robert James Redding | Measurement of distance using ultrasound |
DE3406083A1 (en) * | 1984-02-20 | 1985-08-22 | Siemens AG, 1000 Berlin und 8000 München | WIRELESS WORKING SIGNAL TRANSMISSION SYSTEM |
EP0201989A2 (en) * | 1985-04-12 | 1986-11-20 | United Kingdom Atomic Energy Authority | Ultrasonic range finding |
-
1994
- 1994-10-18 DE DE19944437205 patent/DE4437205A1/en not_active Withdrawn
Patent Citations (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2253975A (en) * | 1938-09-26 | 1941-08-26 | Radio Patents Corp | Distance determining system |
US3433058A (en) * | 1966-05-04 | 1969-03-18 | United Eng Foundry Co | Acoustic flatness measurement device |
GB1533630A (en) * | 1975-09-22 | 1978-11-29 | Eastman Kodak Co | Sheet detecting method and apparatus |
US4054862A (en) * | 1975-10-28 | 1977-10-18 | Raytheon Company | Ranging system with resolution of correlator ambiguities |
GB2121174A (en) * | 1982-05-20 | 1983-12-14 | Robert James Redding | Measurement of distance using ultrasound |
DE3406083A1 (en) * | 1984-02-20 | 1985-08-22 | Siemens AG, 1000 Berlin und 8000 München | WIRELESS WORKING SIGNAL TRANSMISSION SYSTEM |
EP0201989A2 (en) * | 1985-04-12 | 1986-11-20 | United Kingdom Atomic Energy Authority | Ultrasonic range finding |
Non-Patent Citations (4)
Title |
---|
DOUSSIS,E.: A Hardware-level Method to Improve the Range and Accuracy of an Ultrasonic Ranging System. In: ACUSTICA, Vol.78, 1993, S.226-232 * |
FIGUEROA,J.F. * |
GAST,Theodor * |
KÄSTEL,Walter: Eine Ultraschall-Ab- standsmeßeinbrichtung mit dekrementaler Meßwert- gewinnung. In: Technisches Messen tm, 1979, H.7/8, S.293-295 * |
Cited By (10)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE19628849C2 (en) * | 1996-07-17 | 2002-10-17 | Eads Deutschland Gmbh | Acoustic directional emitter through modulated ultrasound |
EP0969292A2 (en) * | 1998-06-30 | 2000-01-05 | Subacoustech Limited | Distance measuring systems, altimeters and aircraft |
EP0969292A3 (en) * | 1998-06-30 | 2002-01-16 | Subacoustech Limited | Distance measuring systems, altimeters and aircraft |
DE19841154A1 (en) * | 1998-09-09 | 2000-04-06 | Holger Loehmer | Measurement of propagation time of sound waves; involves measuring phase shift between transmitted and received signals at two different frequencies |
DE19841154C2 (en) * | 1998-09-09 | 2002-11-07 | Holger Loehmer | Method and device for measuring the transit time of sound waves |
DE10142364A1 (en) * | 2001-08-30 | 2003-04-03 | Advanced Acoustix Gmbh | Determination of the distance to a soft sound object, whereby measurements are made at two or more different frequencies so that a material dependent phase correction can be made |
WO2005019858A1 (en) * | 2003-08-26 | 2005-03-03 | David Antony Crellin | A method of and apparatus for measuring a change in distance between two locations |
DE102007060346A1 (en) * | 2007-12-14 | 2009-06-18 | Hochschule Offenburg | Delay measuring method for two dimensional or three dimensional-positioning of objects, involves evaluating correlation signal according to magnitude and phase for determining delay of ultrasonic pulse at transmission path |
DE102011004830A1 (en) | 2011-02-28 | 2012-08-30 | Holger Löhmer | Method for measuring propagation velocity of sound waves in e.g. liquid medium, involves determining approximation of propagation velocity of sound waves in measuring section based on phase angles of sound waves |
DE102011004830B4 (en) * | 2011-02-28 | 2015-10-29 | Holger Löhmer | Phase method for measuring the propagation velocity of sound waves with dynamic measurement window |
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8139 | Disposal/non-payment of the annual fee |