EP3017318A1 - Näherungssensor und verfahren zur messung des abstands eines objekts - Google Patents
Näherungssensor und verfahren zur messung des abstands eines objektsInfo
- Publication number
- EP3017318A1 EP3017318A1 EP13753410.3A EP13753410A EP3017318A1 EP 3017318 A1 EP3017318 A1 EP 3017318A1 EP 13753410 A EP13753410 A EP 13753410A EP 3017318 A1 EP3017318 A1 EP 3017318A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- wave
- waveguide
- distance
- proximity sensor
- reflection
- 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.)
- Ceased
Links
Classifications
-
- 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
- G01S13/00—Systems using the reflection or reradiation of radio waves, e.g. radar systems; Analogous systems using reflection or reradiation of waves whose nature or wavelength is irrelevant or unspecified
- G01S13/02—Systems using reflection of radio waves, e.g. primary radar systems; Analogous systems
- G01S13/06—Systems determining position data of a target
- G01S13/08—Systems for measuring distance only
- G01S13/32—Systems for measuring distance only using transmission of continuous waves, whether amplitude-, frequency-, or phase-modulated, or unmodulated
-
- 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
- G01S13/00—Systems using the reflection or reradiation of radio waves, e.g. radar systems; Analogous systems using reflection or reradiation of waves whose nature or wavelength is irrelevant or unspecified
- G01S13/02—Systems using reflection of radio waves, e.g. primary radar systems; Analogous systems
- G01S13/06—Systems determining position data of a target
- G01S13/08—Systems for measuring distance only
- G01S13/32—Systems for measuring distance only using transmission of continuous waves, whether amplitude-, frequency-, or phase-modulated, or unmodulated
- G01S13/36—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
-
- 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
- G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
- G01S7/02—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S13/00
- G01S7/35—Details of non-pulse systems
- G01S7/352—Receivers
- G01S7/358—Receivers using I/Q processing
Definitions
- the invention is based on a proximity sensor and a method for measuring the distance of an object according to the preamble of the independent claims.
- the patent EP 1 000 314 B1 describes a circular-cylindrical distance measuring device which is based on the determination of the resonant frequency of a cavity resonator.
- the resonator is formed from the resonator housing and the object to be detected.
- the physical resonator length is composed of the length of the resonator housing and the distance to the object. If a minimum size of the object to be detected is exceeded, the resonance frequency is linked directly to the length of the resonator, from which it is possible to deduce the object distance.
- the exact relationship between resonator length and resonant frequency depends on the field distribution and thus on the waveguide wave mode used.
- the decisive factor in the design is the electrical permittivity of the waveguide filling. If this value increases, on the one hand, the overall length of the
- a metallized dielectric is provided as resonator rear wall, on which the evaluation electronics are located on the outside.
- a coplanar slot coupling or a microstrip line is proposed.
- the coupling by means of microstrip line is especially helpful if the evaluation electronics to be mounted remotely from the resonator, for example, for reasons of thermal decoupling.
- either one or two coupling points can be realized, depending on whether the resonator is to be used in the transmission or reflection mode.
- the evaluation electronics contains an adjustable oscillator whose frequency is tuned in a linear manner within a certain bandwidth and the resulting reflection or transmission factor of the resonator is observed. In the vicinity of a resonant frequency, these factors have large variations that can be systematically identified by differentiating by frequency. Since the circuitry has a linear relationship between frequency and time due to the activation, the derivative with respect to the frequency can be obtained by means of a derivative with respect to time. If the second derivative thus obtained exceeds a predetermined threshold, a resonance is detected and the frequency is no longer detuned but held constant and its current value is determined by means of a frequency counter.
- EP 1 000 314 B1 proposes a concept based on a closed-phase-locked loop (PLL).
- the setpoint frequency is specified via a direct digital synthesizer (DOS) as the reference variable of the PLL. If the detection circuit detects a resonance, the frequency is determined by the settings of the di- digital synthesizer immediately known, whereby the cycle time of a measurement can be significantly shortened.
- DOS direct digital synthesizer
- Resonator method disadvantageous fact that the distance range to be detected directly specifies the required bandwidth of the operating frequency.
- the usable bandwidth is fixed and thus the distance range.
- ISM bands Industrial, Scientific and Medical Band
- a frequency range is proposed for operation between 1 - 100 GHz, the bandwidth being approximately 2 GHz or 10%.
- ISM bands Industrial, Scientific and Medical Band
- the decreasing quality of the resonator leads only to weakly expressed minima in the reflection or transmission factors, as a result of which the detection of the associated resonant frequencies becomes error-prone. This can be seen by illustrating the location of the resonant frequency in the complex frequency plane.
- the complex natural frequency moves away from the ⁇ -axis, which means that no more singularity can be traversed when the oscillator is detuned.
- the limited range is additionally due to the choice of the TE01 mode used, since the field distribution around the waveguide in this case has predominantly evanescent waves, which decay rapidly with increasing distance.
- a groove guide in microwave technology, is understood to mean a waveguide which contains two opposing plates into which a notch of rectangular cross-section is respectively introduced in the propagation direction. The entire arrangement is symmetrical with respect to a plane whose normal coincides with the connecting line of both plates. In the space provided by the notches and the conductive plates, wave modes propagatable toward the notch may exist. Due to the required symmetry and the strong dependence of the propagation properties of the plate spacing, this waveguide places high demands on the manufacturing accuracy.
- the notch is no longer straight, but circular introduced for the realization of a resonator, so that a circular conductor loop is formed.
- a resonance occurs if and only if an integer multiple of the guided wavelength just corresponds to the circumference of the conductor. Since the guided wavelength is a function of the plate spacing and the frequency, the resonance condition can be satisfied within a certain bandwidth for different distances and from this the information about the distance can be obtained.
- the oscillator is excited by means of a Gunn element, causing the oscillator to oscillate at its natural frequency.
- the frequency is then determined by a heterodyne system in which the down-converted natural frequency is fed to a frequency counter.
- the distance sensor described has a large size, since the diameter of the resonator must be chosen to be relatively large in order to keep the radiation losses in the radial direction small.
- the diameter of the described resonator is for operation between 8 - 12 GHz 60 mm with a plate size of 200 mm x 200 mm.
- the measuring range achieved ranges from 13 to 15 mm. If the plate spacing is further increased, higher wave modes can occur in the considered frequency range, which results in ambiguity.
- the distance sensor includes a high frequency line connected to an oscillator and to a reflectance measuring device.
- the position of the work spindle relative to the high-frequency line influences the reflection behavior, so that it is possible to deduce the distance from the determined reflection factor.
- the High frequency line is realized for example as a microstrip line, which is made of flexible material which is fixed by gluing on the surface of the stationary part of the machine tool.
- a high-frequency transmission signal provided by an oscillator is coupled into the high-frequency line.
- a part of the transmission signal is decoupled from a first directional coupler and fed to a first power detector.
- the majority of the transmission signal is fed into the high-frequency line after passing through a second directional coupler.
- the reflected back from the object reflection signal is superimposed on the transmission signal.
- a part of the reflection signal is decoupled from the second directional coupler and fed to a second power detector.
- the two power detectors are connected to an evaluation unit, which determines the ratio of the two powers, that is, the reflection factor and outputs, from which a measure of the distance of the object can be specified.
- a dielectric resonator which effects a pronounced resonance behavior of the distance sensor.
- a change in the distance of the object from the dielectric resonator results in a shift in the resonant frequency of the dielectric resonator.
- the determination of the distance of the object can then additionally or alternatively be based on the evaluation of the frequency change.
- the invention has for its object to provide a proximity sensor and a method for measuring the distance of an object with a wide detection range, which are also almost independent of the permeability of the metallic object to be detected.
- the invention is based on a proximity sensor for measuring the distance of an object from the proximity sensor.
- the proximity sensor includes a microwave oscillator which provides as an output signal a transmission wave which the proximity sensor radiates towards the object as a free space transmission wave which reflects the object which is electrically conductive or at least has an electrically conductive surface as a free space reflection wave and the Proximity sensor receives as a reflection wave, wherein a determination of the reflection factor of the transmission wave and the reflection wave is provided, which provides the proximity sensor as a measure of the distance.
- the proximity sensor according to the invention is characterized in that the transmission wave is guided in a waveguide as a waveguide transmission wave, that the coupling of the transmission wave is provided in the waveguide with a wave mode, for the replacement of the waveguide transmission wave at the aperture at the front end of the waveguide into the free space broadcast wave and propagate the free space broadcast wave to the object.
- the proximity sensor according to the invention offers, for example, inductive proximity sensors a considerably wider measuring range, which can be greater by up to a factor of 10, and a larger linearity range.
- proximity sensor With the proximity sensor according to the invention, very small distances in the range of zero to a few centimeters can be detected, for example, with respect to a proximity sensor according to the standard radar principle, which inherently has a blind range from zero to a minimum distance.
- the proximity sensor according to the invention Compared to a proximity sensor that exploits a characteristic resonance characteristic, the sometimes time-consuming search for a resonant frequency is eliminated and the bandwidth is independent of the distance measuring range, whereby a very narrow-band operation or even operation with zero bandwidth is possible. Due to the omission of a modulation of the transmission wave and omission of the discontinuous operation of the microwave oscillator, the proximity sensor according to the invention requires only a small high-frequency bandwidth. Therefore, even the bandwidth is zero possible. As a result, the proximity sensor according to the invention easily adopts the applicable EMC regulations.
- Another significant advantage of the proximity sensor according to the invention is that the measurement result is largely independent of the permeability of the object.
- the proximity sensor according to the invention in standard designs of known inductive proximity sensors can be realized.
- a propagating free-space transmission wave is achieved with the comparatively simple excitation of the circular waveguide associated TE1 1 mode of the waveguide transmission wave.
- the waveguide can in principle be configured rectangular or circular cylindrical be.
- An advantageous embodiment provides that the waveguide is designed circular cylindrical.
- Another advantageous embodiment of the proximity sensor according to the invention provides that at the aperture at the front end of the waveguide, a dielectric window is provided.
- the dielectric window prevents the ingress of dirt into the waveguide.
- the entire waveguide can be filled with a dielectric material. With this measure, it is possible to fix a preferably existing Wellentypwandler directly in the waveguide.
- the coupling of the transmission wave with its predetermined wave mode is most easily achieved with a Wellentypwandler that converts the line transmission wave in the waveguide transmission wave.
- a quadrature mixer or, alternatively, the 6-port technique is particularly advantageous to use due to the availability as a finished technical solutions.
- the inventive method for measuring the distance of an object wherein an output signal of a microwave oscillator is provided as a transmission wave, which is emitted toward the object as a free-space transmission wave, which from the object which is electrically conductive or at least has an electrically conductive surface is reflected as a free-space reflection wave and received as a reflection wave, the reflection factor from the transmission wave and the reflection wave is determined and provided as a measure of the distance, characterized in that the transmission wave in a waveguide is performed as a waveguide transmission wave, that the coupling of the transmission wave is made in the waveguide with a wave mode for the replacement of the waveguide transmission wave at the aperture at the front end of the waveguide in the free space transmission wave and for propagating the free space transmission wave to the object leads.
- the method according to the invention may also be referred to as a method for operating the proximity sensor according to the invention. Therefore, the advantages already presented for the proximity sensor according to the invention are also present in the method according to the invention.
- the wave mode of the circular waveguide associated TE11-mode is advantageously provided.
- the inventive method allows the determination of the distance at only one frequency of the transmission wave and only one predetermined wave mode.
- An alternative or additional embodiment provides that, to determine the distance, a tuning of the microwave oscillator is performed alternately to at least two different frequencies of the transmission wave.
- a tuning of the microwave oscillator is performed alternately to at least two different frequencies of the transmission wave.
- An embodiment provides that at least one second wave mode is provided for coupling the transmission wave into the waveguide alternately to the first wave mode. With this measure it is provided according to another alternative or according to an additional embodiment that the determination of the distance is made at a single frequency of the transmission wave and at least at two different wave modes.
- At least one such further wave mode is provided, which leads to a predominantly evanescent field distribution in front of the waveguide, which differs significantly from the propagating free space transmission wave, so that the difference is as large as possible.
- Particularly suitable for this purpose is the round waveguide associated TM01 mode.
- the described embodiments make it possible to determine the distance in at least two different ways, so that the results determined on the different types can be made plausible and / or unambiguous.
- a direct measure of the distance of the object from the aperture of the waveguide is obtained by means of a retroactive calculation of the determined reflection factor from the transmission wave and the reflection wave to the reflection factor occurring at the aperture of the waveguide.
- the recalculation preferably takes place with a conformal image which is angle-preserving so that the essential phase information is not lost.
- the measure of the distance can already be obtained from the phase of the reflection factor alone.
- the amount of the reflection factor is further taken into account.
- an unambiguous determination of the distance from the phase of the reflection factor can then be obtained on the basis of the magnitude of the reflection factor if there is ambiguity in the phase of the reflection factor within the predetermined measuring range.
- advantageous refinements provide a rough calibration and, If necessary, additionally a fine calibration.
- the distance is provided as an analog signal.
- a switching signal is provided which signals that a certain distance has been exceeded or fallen short of.
- FIG. 1 shows a sketch of a proximity sensor according to the invention
- Figure 2a shows a diagram of the electric field strength in a cross section of a
- FIG. 2b schematically shows a resulting field strength distribution in the waveguide and in the free field in an excitation according to FIG. 2a
- FIG. 3 a shows a diagram of the electric field strength in a cross section of a waveguide at a second excitation
- FIG. 3b schematically shows a resulting field strength distribution in the waveguide and in the free field in an excitation according to FIG. 3a
- FIG. 4a shows a block diagram of a signal processing system
- FIG. 4b shows a block diagram of a quadrature mixer
- FIG. 4c shows a block diagram of a 6-port technique
- FIG. 5a shows an amount of a measured complex reflection factor.
- FIG. 5b shows a phase angle of a measured complex reflection factor
- FIG. 6a shows an amount of a measured complex reflection factor after a conformal mapping
- Figure 6b shows a phase angle of a measured complex reflection factor after a conformal mapping
- Figure 7 shows a measured reflection factor at two different frequencies after a conformal mapping.
- FIG. 1 shows a sketch of a proximity sensor 10 according to the invention, which detects the distance D between the proximity sensor 10 and an object 12.
- a signal-processing arrangement 14 provides a transmission wave 16, which is guided in a high-frequency line 18 as a line transmission wave 16 a to a shaft type converter 20.
- the mode converter 20, which converts the line-connected two-wire wave mode (QTEM) of the line transmission wave 16a into a predetermined waveguide wave mode, couples the line transmission wave 16a into a waveguide 22.
- QTEM line-connected two-wire wave mode
- the waveguide 22 has a predetermined cross section, which may be, for example, rectangular or circular cylindrical.
- a circular cylindrical design is advantageous, with a direct exchange of existing inductive proximity sensors with circular cylindrical housings against the proximity sensor 10 according to the invention is possible in a simple manner.
- existing brackets can be used.
- the excited waveguide transmission wave 16b propagates in the waveguide 22, reaches an opening or aperture 26 at the front end of the waveguide 22 and determines the field distribution in the region of the aperture 26.
- the waveguide transmission wave 16b running in the waveguide 22 whose wavefronts are sketched in FIG. 1 occurs at the aperture 26 of the waveguide 22 as radiated dominant free-space transmission wave 16c, from which the wavefronts are likewise sketched.
- the aperture 26 of the waveguide 22 corresponds to the active surface of the
- the waveguide 22 may have a dielectric window 28 at its aperture 26 at the front end.
- the dielectric window 28 prevents the penetration of dirt into the waveguide 22.
- dielectric materials are considered which have the lowest possible transmission loss for the waveguide transmission wave 16b. Suitable materials include Teflon or alumina.
- the electrical permittivity of the material plays a role, since this variable, in addition to the diameter d, is directly included in the resulting characteristic impedance of the waveguide wave modes.
- Transmission wave 16b to the radiated free-space transmission wave 16c takes place.
- FIG. 1 shows the embodiment in which the wave-type converter 20, viewed in the direction of the transmission shaft 16, is positioned outside the waveguide 22 for illustrative purposes.
- the radiated free-space transmission wave 16c impinges on the object 12, which is located in the specific distance D in front of the aperture 26 of the waveguide 22.
- the proximity sensor 10 according to the invention detects and provides a measure of the distance D between the aperture 26 of the waveguide 22 and the object 12.
- the object 12 which is either completely made of an electrically conductive material or has at least one surface made of an electrically conductive material, reflects the free-space transmission shaft 16c running outside the waveguide 22, so that a reflection wave 30 occurs, which initially takes the form of a free space.
- Reflection wave 30a is present, from which the wave fronts are sketched in Figure 1.
- the free-space reflection wave 30a passes through the aperture 26 back into the waveguide 22, in which the reflection wave 30 is present as a waveguide reflection wave 30b, again the wave fronts of the waveguide reflection wave 30b are sketched.
- the waveguide reflection wave 30b is converted in the wave type converter 20 into a line reflection wave 30c and arrives as a reflection wave 30 in the signal processing arrangement 14th
- the entire arrangement between the signal-processing arrangement 14 and the object 12 can be viewed in sections as a high-frequency line, which is sketched schematically in the lower part of Figure 1.
- Each section can be assigned an input impedance ⁇ - ⁇ , Z2, Z3 or a reflection factor ⁇
- a measure of the distance D can be determined.
- the phase Ph l ⁇ i of the reflection factor ⁇ represents an initially ambiguous measure of the distance D as a function of the known frequency of the transmission wave 16.
- the first impedance Zi or the first reflection factor ⁇ -1 occurs at the aperture 26 of the waveguide 22. Furthermore, it is assumed that there is air in the free space whose characteristic impedance is at least approximately 377 ohms. Instead of air, however, it is also possible to provide another medium, for example a dielectric wall, in which case the characteristic impedance changes accordingly.
- the third reflection factor ⁇ 3 at the beginning of the high frequency line 18 at the position of the signal processing device 14 is measured.
- the essential advantage is that the measurement can be carried out within the signal-processing arrangement 14.
- the entire arrangement between the signal-processing arrangement 14 and the object 12 can be represented as a cascade of different line sections 32, 34, 36.
- the line sections 32, 34, 36 are formed by the space dependent on the distance D, the waveguide 22 and the high-frequency line 18, neglecting the Wellentypwandlers 20.
- Each line section 32, 34, 36 has a certain characteristic impedance, an (input) impedance ⁇ - ⁇ , Z2, Z3 and a (input) reflection factor ⁇
- the reflection factors ⁇ , l ⁇ 2, ⁇ 3 are each related to the characteristic impedance of the corresponding section 32, 34, 36.
- the phase of the first reflection factor ⁇ 1 has a sectionally linear functional relationship from the distance D. With increasing distance D results for the amount of the first reflection factor ⁇ a monotonically decreasing function.
- the next line section 34 which corresponds to the waveguide 22, transforms the impedance Z1 into the impedance Z2.
- the reflection factor ⁇ is a complex quantity and defined as the quotient of the reflection wave 30 and the transmission wave 16.
- the reflection factor ⁇ for example, by the following context according to a conforming Where Z re f is a normalization impedance that can be determined during a coarse calibration described below: r _ Z 3 -Z ref
- the free space transmission shaft 16c has at least temporarily a dominating contribution of a plane wave propagating in the direction of the object 12.
- the field distribution in the aperture 26 is predetermined by the wave mode distribution in the waveguide 22. Therefore, a wave mode is excited which leads explicitly predominantly to a free-space transmission wave 16c propagating in the direction of the object.
- the waveguide transmission wave 16b should accordingly pass with as few reflections on the aperture 26 into the free-field transmission wave 16c.
- both the characteristic impedance of the wave waveguide mode as possible correspond to the wave resistance of the free space and its field distribution as possible that of a plane wave.
- These conditions can be met, for example, by the fundamental wave mode of a rectangular or circular cylindrical waveguide 22. In accordance with the applicable standard for inductive proximity sensors, a circular cylindrical design is specified.
- the waveguide 22 is preferably realized as a circular cylindrical waveguide 22, preferably with a circular cross-section.
- a freely selectable other cross-section of the waveguide 22, for example a rectangular cross-section can also be provided in principle.
- FIGS. 2a-3b show two different field distributions using the example of a circular-cylindrical waveguide 22.
- the field distributions are caused by a monomodal excitation in the circular cylindrical waveguide 22.
- FIG. 2a shows an excitation 40 in the TE11 mode associated with a circular waveguide.
- the electric field strength 40 is sketched in a cross section of the waveguide 22, the amount and direction are symbolized by the registered triangles.
- the corresponding field distribution 42 within the waveguide 22 and the field distribution 44 in the free space in front of the aperture 26 of the waveguide 22 are shown in a plan view in Figure 2b.
- the excitation in the TE11 mode leads predominantly to a desired free-space transmission wave 16c propagating in the direction of the object D.
- a propagating free-space transmission wave 16c is to be provided at least temporarily by the proximity sensor 10 according to the invention.
- FIG. 3a shows a second excitation in the TM01 mode associated with a circular waveguide.
- the electric field strength 46 is sketched in a cross section of the waveguide 22, whose amount and direction are symbolized by the registered triangles.
- the corresponding second field distribution 48 within the waveguide 22 and second field distribution 50 in the free space in front of the aperture 26 of the waveguide 22 are shown in a plan view in FIG. 3b.
- the excitation in the TM01 mode leads to a predominantly evanescent field distribution 50 in the free space in front of the aperture 26.
- the determination of the reflection factor ⁇ , in particular the third reflection factor l ⁇ 3 takes place in the signal processing arrangement 14, the block diagram of which is shown in FIG. 4a.
- the signal processing arrangement 14, whose components can be arranged according to an advantageous embodiment in the rear end of the waveguide 22, includes a microwave oscillator 52, the output signal 54 are provided both a directional coupler 56 and a quadrature mixer 58 are available.
- the directional coupler 56 passes the output signal 54 of the microwave oscillator 52 via the high-frequency line 18 to the wave-type converter 20. Further, the directional coupler 56 couples the reflection wave 30 and passes a reflection signal 30 corresponding reflection signal 60 to the quadrature mixer 58 on.
- a switch 62 is provided.
- the switch 62 allows switching from a first frequency of the output signal 54 of the microwave oscillator 52 to at least one further frequency.
- the transmission shaft 16 is separated from the reflection wave 30.
- the directional coupler 56 may be implemented in planar line technology, for example in microstrip technology.
- the reflection factor ⁇ , in particular the third reflection factor ⁇ 3 can be determined on the basis of the separated waves 16, 30, for example by means of quadrature mixing in the quadrature mixer 58.
- a block diagram of the quadrature mixer 58 is shown in Figure 4b.
- the quadrature mixer 58 forms an in-phase and a quadrature component I, Q by mixing the reflection wave 30 with the transmission wave 16.
- the quadrature mixture makes it possible to determine the real and imaginary parts of the complex envelope of the signal to be analyzed, here the reflection signal 60 in terms of amplitude and phase the reference signal, here the output signal 54.
- An alternative option for determining the reflection factor ⁇ is the 6-port technique.
- An implementation example of the 6-port technique is shown in FIG. 4c.
- the 6-port technique also provides the in-phase and quadrature components I, Q.
- a further alternative possibility for determining the reflection factor ⁇ is possible within the scope of a measurement of the standing ripple along line sections.
- Both components I, Q are supplied to a calculation unit 64, which determines therefrom the complex reflection factor ⁇ , in particular the third reflection factor ⁇ 3, and preferably takes on a calibration described below and a measurement value evaluation.
- the calculation unit 64 preferably furthermore contains the conformal mapping 38 for transforming the complex third reflection factor ⁇ 3 into the first complex reflection factor ⁇ -.
- An output signal 66 of the calculation unit 64 can be evaluated directly as a measure of the distance D.
- the microwave oscillator 52, the mode converter 20, the directional coupler 56, the quadrature mixer 58 and the computing unit 64 are arranged on a single board made of high frequency suitable base material, for example glass fiber reinforced Teflon.
- the conformal image 38 is provided, which images the first reflection factor f " i in the complex plane onto a spiral with the reference wave resistance as the center, corresponding to a re-normalization of the characteristic impedance, whereby all the plane waves become free in the space between the apertures 26 and As the wave loses power through losses and radiation, both its propagation constant and its characteristic impedance are complex, which also results in a complex reference wave resistance.
- the course of the third reflection factor ⁇ 3 describes a spiral in the complex reflection factor plane as a function of the distance D whose position results from the individual transformations. Although, in principle, there is still a spiral course, this can result in a complicated course for the third complex reflection factor ⁇ 3 in the usual polar coordinate representation.
- the spiral lies completely in the first quadrant of the Cartesian reflection factor plane.
- the values for the angles of the reflection factor ⁇ 1 in polar coordinates are Range from 0 to ⁇ 12. From the previously linearly decreasing with increasing distance D phase curve, a curve has now emerged, the phase without phase jumps growing phase values. Equally, the transformations produce different maxima and minima in the amount of the reflection factor ⁇ 3.
- the goal of compliant figure 38 is through
- FIG. 5a shows the magnitude of the third reflection factor ⁇ 3 before the conformal mapping and in FIG. 6a after the conformal mapping.
- the result for the magnitude of the third reflection factor ⁇ 3 is a monotonically decreasing function and a linear relationship between the distance D and the phase Ph ⁇ 3.
- the complex third reflection factor ⁇ especially the third reflection factor ⁇ 3 shown in a Smith chart, two curves are shown, which apply to two different frequencies of the transmission shaft 16, which can be switched by means of the switch 62 periodically. From the linear phase curve can directly over the phase constant of the
- Transmission wave 16 to the distance D of the object 12 are closed.
- the association between distance D and phase Ph ⁇ is initially unclear if the detection range of proximity sensor 10 exceeds half the wavelength of transmission wave 16.
- the magnitude profile of the reflection factor ⁇ is additionally evaluated and thus the ambiguity of the pure phase evaluation is eliminated. This evaluation is carried out successfully, since the conformal mapping 38 maps the magnitude of the determined first reflection factor ⁇ to a monotonously decreasing profile.
- At least one coarse calibration but preferably a coarse and a fine calibration are provided according to an advantageous embodiment.
- the basis of both calibrations are measured values (reference values) of the complex reflection factor ⁇ 3, which are generated once after sensor production along the be recorded and stored.
- the number of value pairs to be recorded is determined mainly by the accuracy of the sensor to be achieved.
- the coarse calibration can be carried out, for example, as follows:
- the mode converter 20 it is provided to design the mode converter 20 in such a way that it implements an impedance transformation of Zi directly, as a result of which the conformal mapping can be greatly simplified or even completely eliminated.
- the preferably additionally provided fine calibration can be carried out, for example, as follows:
- whose degree determines the quality of the approximation.
- the degree of the polynomial is in turn limited by the number of development points, which here are the measured reference points. However, since any number of points can be recorded metrologically, an interpolation polynomial for any accuracy can be found.
- the purpose of this polynomial is to perform a coarse measurement of the distance D over the measured amount of the reflection factor ⁇ . This measurement only serves to determine the correct interval of the phase.
- phase curve which occur in practice despite conformal mapping, directly affect the accuracy to be expected in the case of Determination of the distance D down.
- a downstream linearization is preferably carried out in the determination of the distance D.
- phase values at the individual reference positions are determined by the sensor evaluation and the difference between actual and setpoint is determined. All deviations of the phase along the detection range are again represented by a polynomial. Again, an arbitrarily high degree and thus any accuracy can be achieved by any number of measurement points.
- the deviation from the exact phase can be determined during the actual determination of the distance D and the measurement result corrected.
- the proximity sensor 10 according to the invention provides a measure of absolute distances D and requires no reference during operation.
- the proximity sensor 10 According to a development of the proximity sensor 10 according to the invention or of the method according to the invention for measuring the distance D of an object 12, it is provided to determine the reflection factor ⁇ and thus the distance D instead of at a predetermined frequency of the microwave oscillator 54 at at least two different frequencies.
- the switch 62 For switching between the frequencies of the switch 62 is provided which causes the microwave oscillator 52 alternately to provide the output signal 54 with the first and at least one further frequency.
- further spiral-shaped courses 68, 70 are mentioned.
- This embodiment is particularly advantageous for large distances D, since here the course of the magnitude of the reflection factor ⁇ becomes flatter and thus its determination possibly error-prone.
- a further advantageous development provides that instead of a monomodal excitation additional wave modes generated in the waveguide 22 and the reflection factor ⁇ is determined at the different wave modes. As a result, at least one further independent complex variable is obtained, which can be used to determine the distance D and / or to eliminate the ambiguity in the phase Ph ⁇ . In this development, several Wellentyp- converters 20 are required.
- both at least two different frequencies of the transmission wave 16 and at least two different wave modes can be used to determine the distance D.
- the determined measure of the distance D corresponding to the output signal 66 can be provided as an analog signal. Alternatively or additionally, the be provided as a switching signal 66, which signals that certain distance D is exceeded or fallen below.
Landscapes
- Engineering & Computer Science (AREA)
- Radar, Positioning & Navigation (AREA)
- Remote Sensing (AREA)
- Computer Networks & Wireless Communication (AREA)
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Radar Systems Or Details Thereof (AREA)
Abstract
Description
Claims
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
PCT/DE2013/000342 WO2015000452A1 (de) | 2013-07-01 | 2013-07-01 | Näherungssensor und verfahren zur messung des abstands eines objekts |
Publications (1)
Publication Number | Publication Date |
---|---|
EP3017318A1 true EP3017318A1 (de) | 2016-05-11 |
Family
ID=49054177
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP13753410.3A Ceased EP3017318A1 (de) | 2013-07-01 | 2013-07-01 | Näherungssensor und verfahren zur messung des abstands eines objekts |
Country Status (4)
Country | Link |
---|---|
US (1) | US10132922B2 (de) |
EP (1) | EP3017318A1 (de) |
CN (1) | CN105051567B (de) |
WO (1) | WO2015000452A1 (de) |
Families Citing this family (9)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE102014007643A1 (de) * | 2014-05-23 | 2015-11-26 | Astyx Gmbh | Abstandmessvorrichtung, insbesondere für metallische und dielektrische Zielobjekte |
WO2016101940A1 (de) | 2014-12-23 | 2016-06-30 | Balluff Gmbh | Näherungssensor und verfahren zur messung des abstands eines targets |
WO2016141905A1 (de) * | 2015-03-06 | 2016-09-15 | Balluff Gmbh | Näherungssensor und verfahren zur messung des abstands eines targets |
US10731457B2 (en) * | 2016-07-06 | 2020-08-04 | Saudi Arabian Oil Company | Wellbore analysis using TM01 and TE01 mode radar waves |
CN106969820A (zh) * | 2017-03-30 | 2017-07-21 | 上海斐讯数据通信技术有限公司 | 一种体重检测装置的预热控制方法及体重检测装置 |
CN107028609A (zh) * | 2017-03-30 | 2017-08-11 | 上海斐讯数据通信技术有限公司 | 一种体重检测装置的预热方法及体重检测装置 |
DE102018117145A1 (de) | 2018-07-16 | 2020-01-16 | Balluff Gmbh | Multifeldzonen-Näherungssensor sowie ein Verfahren zur Messung eines Abstands eines Objekts vom Multifeldzonen-Näherungssensor |
EP3663796B1 (de) * | 2018-12-03 | 2021-06-02 | Sick Ag | Verfahren zur bestimmung eines abstands |
CN115664626B (zh) * | 2022-12-13 | 2023-05-12 | 紫光同芯微电子有限公司 | 时钟相位确定方法及装置、近场通信芯片和近场通信设备 |
Family Cites Families (10)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2001512229A (ja) | 1997-07-31 | 2001-08-21 | ミクロヴェーレン−テクノロジー ウント センソレン ゲーエムベーハー | 距離を測定するための距離測定装置および方法 |
US6672155B2 (en) * | 2000-10-14 | 2004-01-06 | Endress + Hauser Gmbh + Co. | Apparatus for determining the filling level of a filling material in a container |
CN100390531C (zh) | 2004-06-11 | 2008-05-28 | 清华大学 | 基于微波技术的输气管道泄漏检测定位方法与系统 |
US7319401B2 (en) * | 2004-08-27 | 2008-01-15 | Rosemount Tank Radar Ab | Radar level gauge system with variable alarm limits |
US7518548B2 (en) * | 2005-12-15 | 2009-04-14 | Rosemount Tank Radar Ab | Method for determining quality of measurement in a radar level gauge system |
DE102006030965A1 (de) * | 2006-07-03 | 2008-01-10 | Endress + Hauser Gmbh + Co. Kg | Vorrichtung zur Ermittlung und/oder Überwachung des Füllstandes eines Mediums |
US8018373B2 (en) | 2008-12-19 | 2011-09-13 | Rosemount Tank Radar Ab | System and method for filling level determination |
DE102010009664B4 (de) | 2010-02-27 | 2012-08-16 | Ott-Jakob Spanntechnik Gmbh | Vorrichtung zur Überwachung einer Arbeitsspindel |
US8872694B2 (en) * | 2010-12-30 | 2014-10-28 | Rosemount Tank Radar Ab | Radar level gauging using frequency modulated pulsed wave |
EP2527804B1 (de) * | 2011-05-27 | 2020-04-29 | VEGA Grieshaber KG | Verfahren zur Erkennung von Mehrfach- und Bodenechos |
-
2013
- 2013-07-01 WO PCT/DE2013/000342 patent/WO2015000452A1/de active Application Filing
- 2013-07-01 CN CN201380074940.9A patent/CN105051567B/zh not_active Expired - Fee Related
- 2013-07-01 EP EP13753410.3A patent/EP3017318A1/de not_active Ceased
- 2013-07-01 US US14/895,012 patent/US10132922B2/en active Active
Non-Patent Citations (2)
Title |
---|
None * |
See also references of WO2015000452A1 * |
Also Published As
Publication number | Publication date |
---|---|
US20160124083A1 (en) | 2016-05-05 |
US10132922B2 (en) | 2018-11-20 |
CN105051567A (zh) | 2015-11-11 |
CN105051567B (zh) | 2018-03-30 |
WO2015000452A1 (de) | 2015-01-08 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
WO2015000452A1 (de) | Näherungssensor und verfahren zur messung des abstands eines objekts | |
DE4342505C1 (de) | Verfahren und Vorrichtung zur Messung der Dielektrizitätskonstante von Probenmaterialien | |
DE112014007276B4 (de) | Näherungssensor und Verfahren zur Messung des Abstands eines Targets | |
DE69120091T2 (de) | Vorrichtung und Verfahren zum Detektieren einer Stellung eines Kolbens | |
DE102006052637A1 (de) | Vorrichtung und Verfahren zur Bestimmung zumindest eines Parameters eines Mediums | |
EP1040316B1 (de) | Abstandsmessvorrichtung und verfahren zur bestimmung eines abstandes | |
DE19833220A1 (de) | Abstandsmeßvorrichtung und Verfahren zur Bestimmung eines Abstandes | |
EP2467688A1 (de) | Messsystem zur drahtlosen positionsunabhängigen messung der temperatur | |
DE3150202A1 (de) | Anordnung zur messung der feuchte | |
DE19629593A1 (de) | Anordnung zum Erzeugen und zum Senden von Mikrowellen, insb. für ein Füllstandsmeßgerät | |
WO2011080200A1 (de) | Verfahren und vorrichtung zur ermittlung der position eines kolbens eines kolbenzylinders mit mikrowellen | |
EP2054633B1 (de) | Verfahren und vorrichtung zum bestimmen der position eines kolbens in einem zylinder | |
EP0320442B1 (de) | Verwendung eines dielektrischen Mikrowellen-Resonators und Sensorschaltung | |
DE102011007597A1 (de) | Verfahren zur Impendanzanpassung und Hochfrequenz-Leistungsversorgung | |
DE112015006258B4 (de) | Näherungssensor und Verfahren zur Messung des Abstands eines Targets | |
DE19903183A1 (de) | Hochfrequenz-Abstandsmeßeinrichtung | |
EP1321564A1 (de) | Wäschepflegeeinrichtung mit Feuchtsensor und Verfahren zur Bestimmung des Feuchtegehalts von Wäsche | |
EP2031417A1 (de) | Mikrowellen-Näherungssensor und Verfahren zur Bestimmung des Abstands zwischen einem Zielobjekt und einem Messkopf eines Mikrowellen-Näherungssensors | |
DE202013012904U1 (de) | Näherungssensor | |
DE102005013647B3 (de) | Verfahren und Vorrichtung zur Messung der Materialfeuchte eines Meßgutes | |
DE102016118025A1 (de) | Ringförmiger Richtkoppler insbesondere für mikrowellenbasierte Distanzsensoren | |
DE3044353C2 (de) | Vorrichtung zur Feststellung des Erreichens eines vorbestimmten Füllstandes in einem Behälter | |
DE102009024203B4 (de) | Mikrowellensensor und Verfahren zur Bestimmung dielektrischer Materialeigenschaften | |
WO2016000683A1 (de) | Sensor für eine rollenbahn und verfahren zum erkennen von auf einer rollenbahn befindlichen objekten | |
DE102021209675B4 (de) | Abstimmbare Mikrowellen-Brückenschaltung mittels Phasenschieber und Abschwächer zur Trennung eines Sendesignals von einem Empfangssignal ohne Zirkulator und ESR-Spektrometer |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
PUAI | Public reference made under article 153(3) epc to a published international application that has entered the european phase |
Free format text: ORIGINAL CODE: 0009012 |
|
17P | Request for examination filed |
Effective date: 20150922 |
|
AK | Designated contracting states |
Kind code of ref document: A1 Designated state(s): AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR |
|
AX | Request for extension of the european patent |
Extension state: BA ME |
|
DAX | Request for extension of the european patent (deleted) | ||
STAA | Information on the status of an ep patent application or granted ep patent |
Free format text: STATUS: EXAMINATION IS IN PROGRESS |
|
17Q | First examination report despatched |
Effective date: 20181012 |
|
STAA | Information on the status of an ep patent application or granted ep patent |
Free format text: STATUS: EXAMINATION IS IN PROGRESS |
|
REG | Reference to a national code |
Ref country code: DE Ref legal event code: R003 |
|
STAA | Information on the status of an ep patent application or granted ep patent |
Free format text: STATUS: THE APPLICATION HAS BEEN REFUSED |
|
18R | Application refused |
Effective date: 20210421 |