WO1997032206A1 - Detecteur de gouttes de pluie - Google Patents

Detecteur de gouttes de pluie Download PDF

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Publication number
WO1997032206A1
WO1997032206A1 PCT/JP1997/000589 JP9700589W WO9732206A1 WO 1997032206 A1 WO1997032206 A1 WO 1997032206A1 JP 9700589 W JP9700589 W JP 9700589W WO 9732206 A1 WO9732206 A1 WO 9732206A1
Authority
WO
WIPO (PCT)
Prior art keywords
wave
plate
transmitting means
receiving means
raindrop
Prior art date
Application number
PCT/JP1997/000589
Other languages
English (en)
Japanese (ja)
Inventor
Kohki Ohara
Koichi Hirota
Original Assignee
Aisin Seiki Kabushiki Kaisha
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Aisin Seiki Kabushiki Kaisha filed Critical Aisin Seiki Kabushiki Kaisha
Priority to DE19780261T priority Critical patent/DE19780261T1/de
Publication of WO1997032206A1 publication Critical patent/WO1997032206A1/fr

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Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N29/00—Investigating or analysing materials by the use of ultrasonic, sonic or infrasonic waves; Visualisation of the interior of objects by transmitting ultrasonic or sonic waves through the object
    • G01N29/02—Analysing fluids
    • G01N29/032—Analysing fluids by measuring attenuation of acoustic waves
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N29/00—Investigating or analysing materials by the use of ultrasonic, sonic or infrasonic waves; Visualisation of the interior of objects by transmitting ultrasonic or sonic waves through the object
    • G01N29/02—Analysing fluids
    • G01N29/022—Fluid sensors based on microsensors, e.g. quartz crystal-microbalance [QCM], surface acoustic wave [SAW] devices, tuning forks, cantilevers, flexural plate wave [FPW] devices
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N2291/00—Indexing codes associated with group G01N29/00
    • G01N2291/02—Indexing codes associated with the analysed material
    • G01N2291/024—Mixtures
    • G01N2291/02441—Liquids in porous solids
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N2291/00—Indexing codes associated with group G01N29/00
    • G01N2291/04—Wave modes and trajectories
    • G01N2291/042—Wave modes
    • G01N2291/0423—Surface waves, e.g. Rayleigh waves, Love waves

Definitions

  • the present invention relates to a raindrop sensor for detecting the amount of raindrops attached to a plate member.
  • a transmitting element 12 and a receiving element 14 are opposed to a windshield 11 of an automobile and fixed on a straight line passing through the center thereof, and are fixed to a transmitting element 12 and a receiving element.
  • force bras 12a and 14a made of a lead material and a zinc material-composite resin, and known piezoelectric elements 12b and 14b are attached, respectively.
  • the elastic wave emitted by the transmitting element 12 travels while being totally reflected in the windshield and finally enters the receiving element 14.
  • the elastic waves radiated from the transmitting element 12 are repeatedly reflected in the windshield and directly input to the receiving element 14 (reference signal).
  • the elastic wave is not totally reflected in the front glass and the reflection characteristic changes, so that the more raindrops adhered to the front glass, the more the wave receiving element 14 Since the amplitude of the incident ultrasonic wave decreases, this signal is compared with a reference signal to detect the amount of raindrops.
  • an amplifier 31 is connected to the receiving element 14.
  • the amplifier 31 amplifies an AC signal having the same frequency as the transverse wave 5 Ob around the ground potential output from the wave receiving element 14 to increase the amplitude, and to apply a predetermined DC bias to the AC signal.
  • a peak hold circuit 32 is connected to the amplifier 31. This peak hold circuit 3 2 outputs the output signal (amplified The peak value of the AC signal) and outputs a DC voltage corresponding to the amount of raindrops 15 attached to the front glass 11.
  • the peak hold circuit 32 is connected to the judgment circuit 33 and the peak hold circuit 34.
  • the peak hold circuit 34 has a considerably long holding time, and holds and stores the peak value of the output signal (AC signal) from the peak hold circuit 32 to minimize the amount of raindrops 15 attached to the front glass 11. Is output as the reference level “no raindrop”.
  • a volume 35 is connected to the judgment circuit 33.
  • the Helsingborg Interview one arm 35 sets the first determination level T hi and second determination level T h 2 for determining the amount of raindrops 1 5 (see FIG. 6).
  • the judgment circuit 33 determines the difference between the output level, which is the output signal (DC voltage) from the peak hold circuit 32, and the reference level, which is the output signal (direct voltage) from the peak hold circuit 34, and makes a first judgment.
  • the level T hi and the second determination level T h ⁇ are compared to determine the amount of raindrop 15 attached to the front glass 11.
  • a low mode drive circuit 20 for driving the wiper module 25 at low speed and a high mode drive circuit 21 for driving at high speed are connected to the judgment circuit 33.
  • a switch 37 is connected to the judgment circuit 33 and the peak hold circuit 34 via a one-shot multi-circuit 36. Have been.
  • the one-shot multi-circuit 36 outputs a single pulse to the rising and falling portions of the output signal of the switch 37.
  • the one-shot multi-circuit 36 outputs a single pulse. This output activates the mouth mode drive circuit 20 to drive the wiper circuit 25, and also resets the output signal from the peak hold circuit 32 stored in the peak hold circuit 34. As a result, the wipers 22 L and 22 R wipe the windshield 11 once. When the rainwater 15 adhering to the windshield 11 is removed by this wiping operation, an output signal of the peak value is output from the peak hold circuit 32 and stored in the peak hold circuit 34 instantaneously. That is, the reference level is updated.
  • the determination circuit 33 drives the low mode drive circuit 20.
  • the wiper 25 is driven at a normal speed, and the wipers 22 L and 22 R wipe the windshield 11 at a normal speed.
  • the judgment circuit 33 drives the high-mode drive circuit 21 so that the wiper motor 25 becomes lower than the normal speed. It is driven at a high speed and the wipers 22 L and 22 R wipe the front glass 11 quickly.
  • the output level increases, and the difference between the output level and the reference level becomes lower than the first judgment level T hi.
  • the elastic wave radiated from the transmitting element is Most (elastic waves with large amplitudes) propagate from the transmitting element to the receiving element linearly and in a shortest time while reflecting within the windshield, but raindrops etc. between the transmitting element and the receiving element cause front glass.
  • the reflection characteristics change at the part where the raindrops adhere, and the amplitude of the elastic wave reaching the wave receiving element changes.
  • the level of the signal is lower than the signal level of the elastic wave in the ⁇ region. Therefore, even if the reflection direction of the elastic wave changes due to the attachment of raindrops or the like to the front glass, the receiving element receives only the elastic wave signal with a high signal level (the elastic wave signal in the area of the shortest distance). Will wave.
  • the raindrop detection area is limited to the area with the shortest distance between the transmitting element and the receiving element, and becomes narrow.
  • the elastic wave signal from the area with the shortest distance between the two elements has a small difference between the signal when there is no raindrop and the signal when there is raindrop. Is bad.
  • the basic means taken to solve the above technical problem is that at least one of either the transmitting means or the receiving means is directed to a straight line connecting the center of the transmitting means and the center of the receiving means. Either the means is disposed at an angle to the straight line, or a straight line passing through the center of both means is spaced apart and parallel.
  • the elastic wave from the wave transmitting means repeats reflection when reaching the wave receiving means through the plate-like member and does not directly reach the wave receiving means. It is assumed that a wave receiving means is arranged in the device.
  • the elastic wave from the wave transmitting means is repeatedly reflected in the plate-like member and is not directly input to the wave receiving means, that is, the shortest connecting the wave transmitting means and the wave receiving means.
  • the high-level elastic wave signal in the distance region disappears, and the low-level elastic wave signal spreading around the transmitting means makes it possible to detect the surrounding raindrops as a signal level within a constant value region.
  • the signal level of the elastic wave input to the receiving means decreases, and the amount of raindrops attached to the surroundings decreases. It can be detected at least.
  • the wave transmitting means and the wave receiving means are arranged at a predetermined angle with respect to a straight line connecting the centers of the two means, the elastic wave from the wave transmitting means will not be directly input to the wave receiving means.
  • the wave receiving means of the present invention uses a no-raindrop signal as a reference signal, detects a shake with respect to this reference signal, and determines the presence or absence of a raindrop.
  • FIG. 1 is a configuration diagram of a raindrop sensor according to an embodiment of the present invention.
  • (B)-(d) are diagrams showing examples of arrangement of raindrop sensors.
  • FIG. 2 is a cross-sectional view of the wave transmitting element according to the embodiment of the present invention.
  • FIG. 3 is a front view showing an example of mounting a transmitting element and a receiving element.
  • FIG. 4 is a diagram showing an arrangement example of a conventional raindrop sensor.
  • FIG. 5 is a block diagram showing signal processing of the raindrop sensor according to one embodiment of the present invention.
  • FIG. 6 is a waveform at the time of signal processing of the raindrop sensor according to one embodiment of the present invention.
  • FIG. 7 is a diagram showing a detection area when raindrops are detected in the configuration of FIG.
  • FIG. 8 is a diagram showing a detection area when raindrops are detected in the configuration of FIG. 1 (c).
  • a transmitting element 12 and a Z or a receiving element 14 are placed on the front glass 11 of the vehicle with respect to a straight line ( 11 ) connecting the centers of both elements 12 and 14 with an interval. It is fixed at an angle of 0 3 , 0 ⁇ .
  • the transmitting element 12 is angled with respect to the straight line (1) and its center is tilted by 0, and the center of the receiving element 14 is aligned with the straight line (1).
  • 0 3 0.
  • Fig. 2 shows the configuration of each element 12 and 14, and the transmitting element 12 and the receiving element 14 are composed of the force bras 12a and 14a and the piezoelectric elements 12b and 14b, respectively. Each is attached with an adhesive tape or an epoxy-based adhesive, etc., with good ultrasonic permeability.
  • An oscillating circuit 13 shown in FIG. 5 is electrically connected to the piezoelectric element 1 2 b of the transmitting element 12, and the oscillating circuit 13 has a frequency of 1 to 10 MHz. It generates an AC signal of about z.
  • the piezoelectric element 12 vibrates mainly in the thickness direction, and the vibration causes an ultrasonic wave, which is an elastic wave, to be generated in the force bra 12 a. 50 are emitted.
  • the force bra 12 a fixes the piezoelectric element 12 b at a predetermined angle of 0 ° with respect to the front glass 11.
  • the ultrasonic waves 50 emitted by the piezoelectric element 12 b enter the normal n of the front glass 11 at an angle of the predetermined angle 0 j.
  • the incident ultrasonic wave 50 is reflected at the interface between the coupler 12a and the front glass 11 by the difference between the sound velocity in the force bra 12a and the sound velocity in the front glass 11
  • the component of the longitudinal wave 50a and the component of the shear wave 50b are separated by this refraction.
  • the component of the separated longitudinal wave 50a is reduced so as to be radiated in the direction along the interface between the force bra 12a and the front glass 11;
  • the predetermined angle 0 i is determined so that most of 0 is radiated into the front glass 11 as a transverse wave 50.
  • the shear wave 50 b When the shear wave 50 b enters the front glass 11 at a predetermined angle of 0 ° with respect to the normal n of the front glass 11, the shear wave 50 b radiated into the front glass 11 1 is separated from the front glass 11 by the atmosphere (not shown). The light propagates while repeating reflection at the interface with), and finally enters the receiving element 14.
  • the incident ultrasonic waves 50 vibrate the piezoelectric element 14b, and generate a voltage corresponding to the amplitude.
  • the amplitude of the ultrasonic wave 50, that is, the transverse wave 50b, incident on the receiving element 14 is as follows: if the raindrop 15 is attached to the front glass 11, the transverse wave 50b is generated at the portion where the raindrop 15 is attached. Changes in the reflection characteristics of the surface, and the transverse wave 50 b leaks or reflects from the area where the raindrops 15 adhere to the atmosphere. It becomes smaller as the angle changes. That is, the amplitude of the transverse wave 50b incident on the wave receiving element 14 is small when the amount of the raindrop 15 attached to the front glass 11 is large, and is large when the amount of the raindrop 15 is small.
  • the predetermined angle 0 2 is an angle of more than approximately 4 0 degrees. This is because, when the predetermined angle 2 is set to about 40 degrees or more, the longitudinal wave 50a is hardly reflected at the interface between the windshield 11 and the atmosphere. In other words, by setting the predetermined angle 0o to about 40 degrees or more, the front glass 11 operates as a filter for attenuating unnecessary longitudinal waves 50a.
  • the material of the force bra 1 2 a for example, lead material Ya resin material, zinc material, brass and the like are suitable .
  • the predetermined angle 0j is about 25 degrees, and the predetermined angle 0 is about 47 degrees.
  • a predetermined angle 0 j is about 2 5 times, the predetermined angle 0 2 is about 4 degrees.
  • FIG. 5 An example of mounting both elements 12 and 14 is shown in FIG.
  • the edge of the front glass 11 has a black ceramic layer 11a so that the joint surface between the front glass and the vehicle body is not visible from the outside.
  • the transmitting element 12 and the receiving element 14 are arranged at a distance of 100 mm from each other in the manner shown in FIG.
  • both elements 12 and 14 are arranged in front of the steering wheel 11b.
  • FIG. 4 shows the configuration of a conventional device for comparison, and the configuration of the raindrop sensor according to the present invention shown in FIG. 1 (C) was used.
  • the transmitting element 12 and the receiving element 14 are arranged coaxially on the flat glass 11 at a distance (d) of 20 mm, and Piezoelectric elements 12 b and 14 b are mounted on the couplers 12 a and 14 a for the transmitting element 12 and the receiving element 14, and the flat glass 1 of the force bra 1 2 a and 14 a is attached.
  • a vibration of 2.2 MHz is applied to the piezoelectric element 12b, and when the piezoelectric element 12b is vibrated, a water drop (one drop) is applied at a predetermined interval.
  • Figure 7 shows the experimental results obtained by measuring the change in the signal level input to the receiving element 14 with a measuring instrument.
  • Fig. 8 shows the experimental results when the arrangement of the transmitting element 12 and the receiving element 14 was shifted by an angle ⁇ ⁇ (each 25 degrees) (Fig. 8). Ten and-represent only the difference in the direction of the elastic wave).
  • vertical and horizontal lines were drawn at intervals of 10 mm on a flat glass plate made of the same material as the windshield 11 to make a 10 mm square frame, and water droplets were placed in the 10 mm square frame.
  • One was dropped, and the signal level received by the receiving element 14 at that time was measured. This operation was repeated a second time, and signals from all frames were measured.
  • This measurement signal is based on the signal when there is no water (0 dbm) and indicates how much the signal has changed with respect to this reference signal. In other words, this comparison test makes it possible to confirm the presence or absence of raindrops and the detection area of raindrops.
  • the conventional device cannot detect much raindrops at positions other than between transmission and reception.
  • the amplitude of the reflected wave in the flat glass 11 is significantly greater than that of the direct wave that reaches the transmitting element 12 and the receiving element 14 repeatedly by direct reflection. Decay Since the signal arriving at the receiving element 14 is very weak, the detection ability is low.
  • the signal level of the reflected wave radiated from the transmitting element 12 directly input to the receiving element 14 is high, and even if the reflected wave hits a raindrop attached to its surroundings and the signal is detected, it is larger than the direct wave. Due to its weakness, the signal level is much smaller than that of a direct wave. For this reason, the detection sensitivity decreases in the surrounding area, and only the raindrop immediately below the transmitting element 12 and the receiving element 14 can be detected, and the detection area of the raindrop becomes narrow.
  • the ultrasonic waves radiated from the transmitting element 12 are repeatedly reflected in the flat glass 11 and are not directly input to the receiving element 14.
  • the reflection angle changes, and then the reflection is repeated, and the raindrops are detected by the magnitude of the amplitude when reaching the receiving element 14 And the detection range is expanded.
  • the signal level of the ultrasonic wave input to the receiving element 14 is reduced overall, and it is difficult to discriminate raindrops. It is easier to detect raindrops at least.
  • the elastic wave having a high signal level from the transmitting element repeats reflection when reaching the receiving element through the front glass.
  • the elastic wave with a high signal level emitted from the transmitting element is repeatedly reflected in the front glass and directly reflected to the receiving element.
  • the signal is no longer input, and becomes an elastic wave with a low signal level that spreads around the wave transmitting element, and can detect raindrops in a wide area around the element, making it possible to detect raindrops in a wide range.
  • the elastic wave with a high signal level from the transmitting element is not directly input to the receiving element, the signal level of the elastic wave input to the receiving element is reduced as a whole, and the raindrop is determined. And the sensitivity of detecting raindrops is improved.

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  • Physics & Mathematics (AREA)
  • Acoustics & Sound (AREA)
  • Health & Medical Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Chemical & Material Sciences (AREA)
  • Analytical Chemistry (AREA)
  • Biochemistry (AREA)
  • General Health & Medical Sciences (AREA)
  • General Physics & Mathematics (AREA)
  • Immunology (AREA)
  • Pathology (AREA)
  • Measurement Of Velocity Or Position Using Acoustic Or Ultrasonic Waves (AREA)

Abstract

Cette invention concerne l'amélioration de la sensibilité de détection de gouttes de pluies, ainsi que l'élargissement de la zone de détection. A cette fin, un élément émetteur d'ondes (12) et un élément récepteur d'ondes (14) sont disposés de manière à ce qu'une onde élastique, provenant dudit élément émetteur d'ondes (12), ne soit pas réfléchie sans pouvoir ainsi atteindre l'élément récepteur d'ondes (14), mais atteigne directement ce dernier (14) grâce à un écran (11) contre le vent.
PCT/JP1997/000589 1996-02-28 1997-02-27 Detecteur de gouttes de pluie WO1997032206A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
DE19780261T DE19780261T1 (de) 1996-02-28 1997-02-27 Regentropfensensor

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP4168596 1996-02-28
JP8/41685 1996-02-28

Publications (1)

Publication Number Publication Date
WO1997032206A1 true WO1997032206A1 (fr) 1997-09-04

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PCT/JP1997/000589 WO1997032206A1 (fr) 1996-02-28 1997-02-27 Detecteur de gouttes de pluie

Country Status (2)

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DE (1) DE19780261T1 (fr)
WO (1) WO1997032206A1 (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2013242202A (ja) * 2012-05-18 2013-12-05 Hitachi-Ge Nuclear Energy Ltd 超音波検査方法及び超音波検査装置

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH05142356A (ja) * 1991-11-21 1993-06-08 Nisca Corp 超音波による物体検知装置
JPH05262204A (ja) * 1992-03-17 1993-10-12 Mitsubishi Heavy Ind Ltd 曇り除去装置

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH05142356A (ja) * 1991-11-21 1993-06-08 Nisca Corp 超音波による物体検知装置
JPH05262204A (ja) * 1992-03-17 1993-10-12 Mitsubishi Heavy Ind Ltd 曇り除去装置

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2013242202A (ja) * 2012-05-18 2013-12-05 Hitachi-Ge Nuclear Energy Ltd 超音波検査方法及び超音波検査装置

Also Published As

Publication number Publication date
DE19780261T1 (de) 1998-04-02

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