JP2008256521A - Ultrasonic sensor apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ultrasonic sensor apparatus for diagnosing the existence of an abnormality in itself. <P>SOLUTION: The ultrasonic sensor apparatus includes: a plurality of waveguides; at least one transmitting ultrasonic element disposed at one end of the waveguide, and transmitting ultrasonic waves through the waveguide; at least one receiving ultrasonic element for receiving the ultrasonic waves, and outputting a reception signal corresponding to a strength of the ultrasonic waves; and a determination means for determining the existence of the abnormality in one of the ultrasonic elements and the waveguides based on a reception signal of turnaround waves directly turning around and traveling from an end opposite to the transmitting ultrasonic element disposed side of the waveguide to an interior of the waveguide in which the adjacent receiving ultrasonic element is disposed. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an ultrasonic sensor device including an ultrasonic element and a waveguide.

Conventionally, for example, as shown in Patent Documents 1 and 2, a plurality of waveguides are provided, and an ultrasonic element (transmitter, receiver, ultrasonic transducer) is disposed at one end of each waveguide. An ultrasonic sensor device having a configuration in which ultrasonic waves are transmitted via a waveguide is known.
JP-A-63-243783 JP-A-10-224880

  Incidentally, as described above, in the ultrasonic sensor device having the configuration in which the ultrasonic element is arranged at one end of the waveguide, the other end of the waveguide on the ultrasonic element arrangement side is open. When it is attached to a moving body such as a stone, water, sand, mud or other foreign matter may enter the waveguide. It is also conceivable that the ultrasonic element is damaged by the collision of the foreign matter, or the foreign matter existing in the waveguide affects the propagation of the ultrasonic wave. However, the reflected wave by the reflecting object such as an obstacle outside the ultrasonic sensor device varies depending on the presence / absence of the reflecting object, the distance from the reflecting object, the type of the reflecting object (surface unevenness, etc.) and the like. For example, the reflected wave may not be detected not only when there is no reflector but also when there is a reflector. Therefore, even if the received signal due to the reflected wave is different from the normal state (for example, the peak value is small) or not detected, the cause is due to the reflection object or the abnormality of the ultrasonic sensor device itself. It is difficult to determine whether

  In view of the above problems, an object of the present invention is to provide an ultrasonic sensor device capable of diagnosing its own abnormality.

  In order to achieve the above object, an ultrasonic sensor device according to claim 1 includes a plurality of waveguides and an ultrasonic element disposed at one end of the waveguide via the waveguides. At least one transmission ultrasonic element for transmitting ultrasonic waves, at least one reception ultrasonic element for receiving ultrasonic waves and outputting a reception signal corresponding to the intensity of the ultrasonic waves, and transmission ultrasonic waves From the end opposite to the element arrangement side of the waveguide in which the element is arranged, to the reception signal of the sneak wave that is directly propagated and propagated into the waveguide in which the nearby receiving ultrasonic element is arranged And determining means for determining the presence / absence of at least one of the ultrasonic element and the waveguide.

  As described above, according to the present invention, the transmission wave transmitted from the transmission ultrasonic element is not a reflected wave due to a reflection outside the ultrasonic sensor device, but the transmission ultrasonic element is disposed at the end. Using the sneak wave that propagates from the wave tube directly to the waveguide where the receiving ultrasonic element located in the vicinity of the wave tube is placed, the abnormality of the ultrasonic sensor device I try to diagnose. Since the reception signal by such a sneak wave is not affected by the reflection object (existence of reflection object, distance from the reflection object, type of reflection object) outside the ultrasonic sensor device, it is based on the reception signal by the sneak wave. The self-diagnosis of the abnormality of the ultrasonic sensor device can be performed.

  Specifically, as described in claim 2, storage means for storing a peak value of a received signal due to a sneak wave as a first reference value in a state where there is no abnormality in the waveguide through which the sneak wave is propagated. The determination means may be configured to determine that there is an abnormality when no sneak wave is detected or when a sneak wave is detected and the peak value of the received signal is different from the first reference value of the storage means. .

  As described above, the sneak wave is not affected by the reflector. Therefore, when a sneak wave is not detected, it can be determined that the abnormality is caused by, for example, failure of the ultrasonic element or blocking of the waveguide. Further, when the peak value of the received signal is different from the first reference value of the storage means, for example, it can be determined that there is a failure of the ultrasonic element or an abnormality due to a foreign substance that has entered the waveguide.

  In the first or second aspect of the invention, as described in the third aspect of the present invention, the determination means determines the abnormal position based on the attenuation waveform of the output signal of the transmitting ultrasonic element. It is also good.

  If there is an abnormality such as foreign matter in the waveguide where the transmitting ultrasonic element is arranged, and at least part of the transmitted wave output from the transmitting ultrasonic element is reflected by the abnormal part of the waveguide, The ultrasonic element itself receives the reflected wave. That is, the attenuation waveform of the output signal is different from the case where there is no abnormality in the waveguide. Therefore, an abnormal position can be determined based on the attenuation waveform of the output signal of the transmitting ultrasonic element.

  Specifically, as described in claim 4, the storage means has a reverberation time of the output signal of the transmission ultrasonic element in a state where there is no abnormality in the waveguide in which the transmission ultrasonic element is arranged. When the peak value of the received signal is stored as the second reference value and is different from the first reference value of the storage unit, the determination unit determines that the reverberation time of the output signal of the transmitting ultrasonic element is greater than the second reference value of the storage unit. When it is long, it may be configured to determine that the waveguide in which the transmitting ultrasonic element is disposed is abnormal. According to a fifth aspect of the present invention, when there are a plurality of transmission ultrasonic elements and the peak value of the received signal is different from the first reference value of the storage means, the determination means outputs the outputs of the plurality of transmission ultrasonic elements. The reverberation times of the signals may be compared with each other, and when at least one reverberation time is longer than the other reverberation times, it may be determined that the waveguide having a long reverberation time is abnormal.

  In the case of the invention described in claim 4, even if there is an abnormality in the waveguides corresponding to all of the transmitting ultrasonic elements, it can be determined that there is an abnormality in each. In the case of the invention described in claim 5, since the reverberation times of the output signals of the plurality of transmitting ultrasonic elements are compared with each other, the influence of the change in the measurement conditions (for example, the change in the reverberation time due to temperature) is canceled out. Can do.

  Next, an ultrasonic sensor device according to claim 6 transmits at least ultrasonic waves through a waveguide as an ultrasonic element disposed at one end of the waveguide and the waveguide. One transmission ultrasonic element, at least one reception ultrasonic element that receives an ultrasonic wave and outputs a reception signal corresponding to the intensity of the ultrasonic wave, and an attenuation waveform of an output signal of the transmission ultrasonic element And determining means for determining at least whether the waveguide is abnormal or not.

  If there is an abnormality such as foreign matter in the waveguide where the transmitting ultrasonic element is arranged, and at least part of the transmitted wave output from the transmitting ultrasonic element is reflected by the abnormal part of the waveguide, The ultrasonic element itself receives the reflected wave. That is, the attenuation waveform of the output signal is different from the case where there is no abnormality in the waveguide. Therefore, according to the present invention, it is possible to determine at least whether the waveguide is abnormal based on the attenuation waveform of the output signal of the transmitting ultrasonic element.

  In addition, since the effect of the invention of Claim 7 and Claim 8 is the same as the effect of the invention of Claim 4 and Claim 5, respectively, the description is abbreviate | omitted.

  In the invention described in any one of claims 1 to 8, a configuration including notifying means for notifying an occupant of at least an abnormal state based on a determination result by the determining means, as described in claim 9. And good.

  In the invention according to any one of claims 1 to 9, as described in claim 10, the end opposite to the element arrangement side of the waveguide is formed in the through-hole to be attached to the movable body. This configuration is suitable for a configuration in which the ultrasonic element is exposed to the outside through the hole and the ultrasonic element is disposed inside the moving body.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
(First embodiment)
FIG. 1 is a configuration diagram showing the overall configuration of the ultrasonic sensor device according to the first embodiment of the present invention. FIG. 2 is a cross-sectional view showing a schematic configuration of the ultrasonic sensor in the ultrasonic sensor device. FIG. 3 is a plan view of FIG. 2 viewed from the outer surface side of the moving body. FIG. 4 is an enlarged cross-sectional view around the housing in FIG. 2 and 3 show a state in which the ultrasonic sensor is attached to the attached portion of the moving body.

  In the present embodiment, an example in which the ultrasonic sensor device is used in a vehicle as a moving body will be described. Specifically, an ultrasonic sensor is attached to, for example, bumpers on the front, rear, or four corners of the vehicle so that obstacles around the vehicle can be detected.

  As shown in FIG. 1, the ultrasonic sensor device 10 includes an ultrasonic sensor 100, an ECU (Electric Control Unit) 20, a drive signal generation unit 30, a reception signal processing unit 40, and a notification unit 50 as main parts. ing.

  As shown in FIG. 2, the ultrasonic sensor 100 includes, as main parts, a piezoelectric vibrator 110, a casing 120 that houses the piezoelectric vibrator 110, and the like, and induces ultrasonic waves between the outside of the vehicle and the piezoelectric vibrator 110. It includes two ultrasonic sensors 100a and 100b having a tube portion 132 as a waveguide. Note that the housing 120 including the piezoelectric vibrator 110 corresponds to an ultrasonic element in the claims. As such an ultrasonic sensor 100, for example, various configurations described in Japanese Patent Application No. 2007-96704 by the present applicant can be adopted. In Japanese Patent Application No. 2007-96704, each configuration and effect are described in detail, and a detailed description of this embodiment is omitted.

  The piezoelectric vibrator 110 uses piezoelectric ceramics such as barium titanate or PZT as a sintered body, and generates a vibration by applying a voltage. The piezoelectric vibrator 110 is formed in a disk shape, for example. In the present embodiment, the piezoelectric vibrator 100 includes two piezoelectric vibrators 110a and 100b arranged side by side in the horizontal direction (x direction shown in FIG. 3) with respect to the road surface. The piezoelectric vibrator 110a plays a role of transmitting ultrasonic waves to the outside of the vehicle, and the piezoelectric vibrator 100b plays a role of receiving ultrasonic waves.

  An electrode (not shown) is formed on the surface of the piezoelectric vibrator 110, and a lead 111 is electrically connected to the electrode. In the present embodiment, as shown in FIG. 4, one lead 111 is connected to the inner surface of the housing 120 that is electrically connected to the electrode. The lead 111 outputs a drive signal for generating an ultrasonic wave by vibrating the piezoelectric vibrator 110, or when the ultrasonic wave is transmitted to the piezoelectric vibrator 110 and the piezoelectric vibrator 110 is distorted. In addition, it is electrically connected to a circuit board (not shown) on which a processing circuit for inputting a voltage signal generated by the piezoelectric effect is formed. Therefore, the ultrasonic sensor device 10 can calculate the distance to the obstacle existing around the vehicle based on the time from transmission to reception of the ultrasonic wave.

  The casing 120 is provided in a bottomed cylindrical shape using, for example, aluminum or synthetic resin (aluminum in the present embodiment) as a constituent material so as to accommodate one piezoelectric vibrator 110 (110a, 110b). Then, as shown in FIG. 4, the piezoelectric vibrator 110 is installed (for example, fixed) on the inner surface 122 of the bottom surface portion 121. That is, the bottom surface portion 121 on which the piezoelectric vibrator 110 is disposed serves as a diaphragm, and the outer surface 123 (the back surface of the inner surface 122) of the bottom surface portion 121 is a vibration surface.

  Further, as shown in FIG. 4, a sound absorbing material 112 is disposed around the piezoelectric vibrator 110 except for a surface facing the inner surface 122. The sound absorbing material 112 is for absorbing ultrasonic waves radiated into the housing 120 when the piezoelectric vibrator 110 expands and contracts and the bottom surface portion 121 of the housing 120 vibrates. It is made of a material with excellent sound absorption performance. And the sealing material 113 is arrange | positioned on the sound absorption material 112, and the inside of the housing | casing 120 is airtightly sealed by this sealing material 113.

  As shown in FIG. 2, the waveguide unit 130 transmits ultrasonic waves between the outside of the vehicle and the piezoelectric vibrator 110 (the outer surface 123 as a vibration surface) disposed inside the vehicle (the inner surface 3 side of the bumper 2). In this embodiment, in the present embodiment, the ultrasonic wave is guided to the outside of the vehicle from the outer surface 123 of the casing 120 in which the piezoelectric vibrator 110a is arranged, and the ultrasonic wave from the outside of the vehicle is guided in the casing in which the piezoelectric vibrator 100b is arranged. 120 to the outer surface 123 of 120). In the waveguide unit 130 according to this embodiment, two tube portions 132 as waveguides are formed on a base material 131 made of, for example, a resin material. Of the two pipe portions 132, the casing 120 including the piezoelectric vibrator 110a is fixed to the opening end 135a of the pipe portion 132a, and the piezoelectric vibrator 110b is attached to the opening end 135b of the pipe portion 132b. The housing 120 including it is fixed. As described above, the ultrasonic sensor 100a includes the housing 120 including the piezoelectric vibrator 110a and the tube portion 132a, and the ultrasonic sensor 100b includes the housing 120 including the piezoelectric vibrator 110b and the tube portion 132b. It has become.

  The opening ends 133a and 133b on the bumper 2 side of the pipe portions 132a and 132b are opened close to each other on the same surface of the base member 131 as shown in FIG. It is exposed to the outside of the vehicle through the through hole 5 of the bumper 2. The other opening ends 135a and 135b are connected to a fixing groove 134 formed on the opposite surface side of the opening end forming surface of the base material 131, respectively. The fixing groove 134 is a groove in which the housing 120 including the piezoelectric vibrator 110 is fixed.

  Further, as shown in FIG. 2, the pipe portions 132 a and 132 b are set so that the opening areas of the respective opening ends 133 a and 133 b are smaller than the area of the outer surface 123 as a corresponding vibration surface. In the present embodiment, the opening ends 133a and 133b are both circular shapes having the same shape and size while satisfying the above conditions, and the corresponding outer surfaces 123 are also set to have the same shape and size. ing. In addition, each of the pipe portions 132a and 132b has a cross-sectional shape (circular cross-section in the present embodiment) and a cross-sectional area between the opening ends 133a and 133b on the bumper 2 side and the opening ends 135a and 135b on the vibration surface side. Each is constant.

  In addition, as shown in FIG. 2, the opening interval between the adjacent opening ends 133a and 133b is narrower than the corresponding interval between the adjacent outer surfaces 123, and is less than a half wavelength with respect to the wavelength of the ultrasonic wave (this embodiment). In the form, it is half wavelength). Furthermore, the lengths of the plurality of pipe portions 132a and 132b are set to be equal.

  The waveguide unit 130 configured as described above is fixed to the bumper 2 in a state where the casing 120 including the piezoelectric vibrator 110 is fixed to the fixing groove 134. In the present embodiment, a part of the base material 131 including the openings 133 a and 133 b is inserted into the through hole 5 of the bumper 2, and the portion of the base material 131 facing the inner surface 3 of the bumper 2 is bonded to the inner surface 2. It is fixed. In this fixed state, the opening ends 133 a and 133 b are flush with the outer surface 4 of the bumper 2. The housing 120 including the piezoelectric vibrator 110 is fixed to the corresponding fixing groove 134 via the vibration absorbing member 124 so that the outer surface 123 as a vibration surface is on the opening end 133a, 133b side. Yes. Further, in a state where the housing 120 is fixed to the fixing groove 134, the opening ends 135a and 135b of the pipe portions 132a and 132b are disposed on the opening ends 133a and 133b side with a slight gap between the opening ends 135a and 135b. It is in a state. That is, the bottom surface portion 121 as a diaphragm is not in direct contact with the base material 131 constituting the waveguide unit 130, and the base material 131 does not suppress vibration of the bottom surface portion 121.

  The ECU 20 is a normal computer, and includes a CPU, a ROM, a RAM, an I / O (not shown), and a bus connecting them. The ECU 20 outputs a drive instruction signal for the piezoelectric vibrator 110a and a self-diagnosis drive instruction signal to the drive signal generator 30 at a predetermined timing. Further, the ECU 20 detects a wraparound wave and a reflected wave, which will be described later, based on a reception signal of the piezoelectric vibrator 100b, and detects a peak value of the wraparound wave. Then, when no sneak wave is detected, or when the peak value of the sneak wave is different from the first reference value set in advance, it is determined that an abnormality has occurred in the ultrasonic sensor 100. And the output of the alerting | reporting part 50 is controlled so that the alerting | reporting part 50 alert | reports the determination result. Thus, ECU20 which concerns on this embodiment has each function of a memory | storage, determination, a calculation, and control.

  The drive signal generation unit 30 includes an oscillation circuit 31 and a drive circuit 32. The oscillation circuit 31 receives a drive instruction signal or a self-diagnosis drive instruction signal from the ECU 20 and outputs a pulse signal having a preset predetermined frequency to the drive circuit 32. The drive circuit 32 is driven by receiving a power supply voltage input to the piezoelectric vibrator 110a, and drives the piezoelectric vibrator 110a by a pulse signal (drive signal) from the oscillation circuit 31. As a result, the piezoelectric vibrator 110a vibrates and a transmission wave (ultrasonic wave) is transmitted to the outside of the vehicle via the bottom surface portion 121 of the casing 120 shown in FIG.

  The detection signal processing unit 40 includes an amplifying circuit 41 and a filter circuit 42 that selectively outputs only a predetermined frequency range among signals output from the piezoelectric vibrator 110b that converts vibration into an electric signal. . Therefore, the amplified and filtered signal is input to the ECU 20.

  As described above, the notification unit 50 makes notifications according to the determination result and calculation result of the ECU 20 to the occupant. In this embodiment, an alarm sound output device and a display device are employed.

  Next, the principle of determining the presence or absence of abnormality of the ultrasonic sensor device 10 based on the sneak wave will be described with reference to FIGS. FIG. 5 is a diagram for explaining the reflected wave and the sneak wave. 6A and 6B are diagrams showing changes in the received signal according to the presence / absence of abnormality, where FIG. 6A is a state where there is no abnormality and there is an obstacle, FIG. 6B is a state where there is no abnormality and no obstacle, and FIG. It is a figure which shows the state with an obstacle.

  Conventionally, a sound wave has a property of turning to the back side when there is a shield, etc., and this property is weaker as the frequency is higher (shorter wavelength) and stronger as the frequency is lower (longer wavelength). Are known. As shown in this embodiment, the frequency of the ultrasonic sensor device 10 applied to the vehicle obstacle detection device is generally a low frequency of about 40 to 70 kHz, and the frequency within this range is also in this embodiment. (For example, 40 kHz). Therefore, in the configuration shown in the present embodiment, when the obstacle 1 exists outside the vehicle, the obstacle 1 as shown in FIG. 5 based on the ultrasonic wave emitted from the piezoelectric vibrator 100a by the transmission vibration. The reflected wave W1 and the sneak wave W2 are propagated into the receiving tube 132b.

  Due to the above-described nature of the ultrasonic wave, this sneak wave W2 is received from the opening end 133a of the tube portion 132a where the transmitting piezoelectric vibrator 100a is disposed, via the neighboring opening end 133b, and received piezoelectric vibration. It is propagated by directly wrapping around the pipe part 132b in which the child 100b is arranged. Thus, the sneak wave W2 has a shorter propagation path of ultrasonic waves than the reflected wave W1 and does not include the obstacle 1 in the propagation path. Therefore, the presence / absence of the obstacle 1, the distance to the obstacle 1, and the obstacle 1 Are not affected by the obstacle 1 such as the surface type (surface irregularity, acoustic impedance, etc.). Therefore, unlike the reflected wave W1, the sneak wave W2 reflects the change of the ultrasonic sensor device 10 (ultrasonic sensor 100) deeply. In the present embodiment, the presence or absence of abnormality of the ultrasonic sensor device 10 is self-diagnosed based on the received signal by the sneak wave W2.

  For example, when there is no abnormality in the ultrasonic sensor device 10 (the piezoelectric vibrator 110 and the tube portion 132) and the obstacle 1 is present, the received signal detected by the piezoelectric vibrator 110b is shown in FIG. It becomes like this. As shown in FIG. 6A, the sneak wave W1 having a short propagation path is detected first, and then the reflected wave W1 is detected.

  On the other hand, when the obstacle 1 is removed from the state shown in FIG. 6A (when the ultrasonic sensor device 10 has no abnormality and the obstacle 1 does not exist), it is detected by the piezoelectric vibrator 110b. As shown in FIG. 6B, the received signal is only a signal by the sneak wave W2. At this time, the reception signal by the sneak wave W2 is not affected by the obstacle 1 and therefore hardly changes as shown in FIG.

  In addition, when the foreign object is disposed in the tube portion 132 (for example, the foreign material 6 is received tube portion 132b as shown in FIG. 5) from the state shown in FIG. 6A (the ultrasonic sensor device 10 has an abnormality, When the obstacle 1 is present), the sneak wave W2 and the reflected wave W1 are both affected by at least one abnormality of the piezoelectric vibrator 110 (110a, 110b) and the tube portion 132 (132a, 132b). Therefore, the received signal changes from the state of FIG. 6A as shown in FIG. Specifically, when the foreign matter 6 such as stone enters the tube portion 132b and the tube portion 132 is abnormal, the acoustic impedance between the medium (air in the present embodiment) and the foreign material 6 in the tube portion 132b. The difference causes ultrasonic reflection. Therefore, as shown in FIG. 6C, the amplitude (peak value) of the reception signal by the sneak wave W2 and the reflected wave W1 is smaller than that in the state of FIG.

  In this way, unlike the reflected wave W1, the sneak wave W2 is not affected by the obstacle 1, and therefore the self-diagnosis of the abnormality of the ultrasonic sensor device 10 is performed based on the received signal by the sneak wave W2. Can do. In addition, since the reflected wave W1 is a reflected wave by the obstacle 1, it changes with the obstacle 1. For example, the reflected wave may not be detected not only when there is no obstacle 1 but also when the obstacle 1 is present, and the intensity of the received signal also varies depending on the distance to the obstacle 1 and the type of the obstacle 1. Therefore, it is difficult to make a self-diagnosis based on the received signal by the reflected wave W2.

  Various determination methods for determining the presence or absence of abnormality of the ultrasonic sensor device 10 (self-diagnosis) can be considered based on the received signal from the sneak wave W2, and one example will be described with reference to FIG. FIG. 7 is a flowchart illustrating an example of a process for determining whether or not the ultrasonic sensor device is abnormal. For example, this process is executed when the IG key is turned on.

  First, when the IG key is turned on, the ECU 20 issues a self-diagnosis drive signal generation instruction to the oscillation circuit 31 of the drive signal generation unit 30, and the drive signal generation unit 30 that receives the instruction generates a self-diagnosis drive signal. It outputs to the piezoelectric vibrator 110a for transmission. Then, the piezoelectric vibrator 110 a vibrates and a transmission wave (ultrasonic wave) is output via the bottom surface portion 121 of the housing 120. This transmission wave is guided in the tube portion 132a and output to the outside from the opening end 133a.

  Of the transmission waves output to the outside from the open end 133a, the sneak wave W2 is propagated from the open end 133b located near the open end 133a into the receiving tube 132b. When guided through the tube portion 132b and transmitted from the open end 135b to the bottom surface portion 121 of the housing 120, the receiving piezoelectric vibrator 110b converts the vibration of the bottom surface portion 121 into an electrical reception signal. .

  If there is no abnormality, the sneak wave W2 should reach the piezoelectric vibrator 110b in a substantially constant time after the ECU 20 issues a drive signal generation instruction to the drive signal generation unit 30. Therefore, the piezoelectric vibrator 110b detects the sneak wave W2 for a predetermined time after the ECU 20 issues a drive signal generation instruction to the drive signal generation unit 30 (S10). Based on the result, the ECU 20 detects the sneak wave W2. Whether or not there is is determined (S20). Note that the above-mentioned predetermined time is set from when the drive signal generation instruction is issued until the detection of the sneak wave W2 is completed and until the detection of the reflected wave W1 is started.

  When the sneak wave W2 is not detected, it is presumed that at least one of the piezoelectric vibrators 110a and 110b has failed or at least one of the tube portions 132a and 132b is blocked. Therefore, the ECU 20 determines that the ultrasonic sensor device 10 is in an abnormal state, and outputs a notification instruction signal to the notification unit 50. And the alerting | reporting part 50 alert | reports to a passenger | crew by the warning sound and the display on a monitor (S50), and a self-diagnosis process is complete | finished.

  When the wraparound wave W2 is detected, the ECU 20 detects the peak value (amplitude) of the wraparound wave W2 based on the reception signal of the wraparound wave W2 (S30). Then, it is determined whether or not the detected peak value matches a reference value stored in advance in the memory (first reference value described in claims) (S40).

  When the detected peak value substantially coincides with the reference value, the ECU 20 determines that there is no abnormality in the piezoelectric vibrator 110 (110a, 110b) and the pipe portion 132 (132a, 132b), and the self-diagnosis process ends. .

  When the detected peak value is different from the reference value, it is presumed that at least one of the piezoelectric vibrators 110a and 110b has failed, or at least one of the tube portions 132a and 132b has entered a foreign substance. Therefore, the ECU 20 determines that the ultrasonic sensor device 10 is in an abnormal state, and outputs a notification instruction signal to the notification unit 50. And the alerting | reporting part 50 alert | reports to a passenger | crew by the warning sound and the display on a monitor (S50), and a self-diagnosis process is complete | finished.

  In this embodiment, in order to prevent erroneous detection, the ECU 20 is configured not to output a drive signal generation instruction from the ECU 20 to the drive signal generation unit 30 unless a reset process is performed after the abnormality determination. In other words, the ultrasonic sensor device 10 is configured not to function as an obstacle detection device unless inspected, repaired, or replaced. Note that the notification may be turned off upon completion of the determination process, or only the alarm sound may be turned off and the display may remain until the reset process is performed.

  As described above, according to the ultrasonic sensor device 10 according to the present embodiment, the sneak wave W2 that is directly circulated and propagated from the transmitting tube 132a to the receiving tube 132b located in the vicinity thereof. Therefore, the presence or absence of abnormality of the ultrasonic sensor device 10 (ultrasonic sensor 100) can be self-diagnosed without being affected by the obstacle 1. In particular, it is possible to determine whether there is an abnormality regardless of transmission and reception.

  In the present embodiment, an example in which the notification of abnormality is an alarm sound and a display on a monitor is shown. However, the notification unit 50 is not limited to the above example. In addition, a display device attached to the instrument panel of the vehicle can be employed.

  In the present embodiment, an example in which the determination process is executed when the IG key is turned on has been described. However, the configuration may be such that the determination process is executed according to the shift position. For example, when the ultrasonic sensor 100 is disposed on the rear bumper 2, the determination process shown in FIG. 8 may be executed when the shift position is set to R (reverse). In this case, the determination process is executed as a previous stage of the obstacle detection process. As shown in FIG. 8, the abnormality presence / absence determination process is executed in the same manner as the above-described processes (S10 to S50). In S40, when the ECU 20 determines that the peak value and the reference value match, the reflected wave detection (S60) is detected by the detecting piezoelectric vibrator 110b. Then, the ECU 20 executes a predetermined calculation process (S70) based on the received signal of the reflected wave, and determines whether there is an obstacle based on the calculation result (S80). Only when it is determined that there is an obstacle, the ECU 20 outputs a notification instruction signal to the notification unit 50, and the notification unit 50 notifies the occupant, for example, with an alarm sound (S90). The processes of S60 to S90 are repeatedly executed until there is a shift position change (D or P), and the determination process is ended by the shift position change (S100). FIG. 8 is a flowchart showing a modification. Although FIG. 8 shows an example in which the reflected wave is detected in S60, the reflected wave may be detected after S10 and before S70.

  In the present embodiment, as the simplest example, the ultrasonic sensor 100 includes, as the piezoelectric vibrator 110, one piezoelectric vibrator 110a dedicated for transmission and one piezoelectric vibrator 110b dedicated for reception. Indicated. However, the configuration of the ultrasonic sensor 100 is not limited to the above example. Any structure may be used as long as it has at least two piezoelectric vibrators 110 (two pipe portions 132), at least one of which has a transmission function and at least one of which has a reception function. For example, a configuration including a plurality of piezoelectric vibrators 110 having a transmission / reception function may be employed.

(Second Embodiment)
Next, 2nd Embodiment of this invention is described based on FIGS. FIG. 9 is a diagram for explaining reverberation. 10A and 10B are diagrams illustrating changes in the transmission wave, where FIG. 10A illustrates a case where there is an abnormality on the reception side, and FIG. 10B illustrates a case where there is an abnormality on the transmission side. FIG. 11 is a flowchart illustrating processing for determining whether or not the ultrasonic sensor device is abnormal in the second embodiment.

  Since the ultrasonic sensor device according to the second embodiment is often in common with the ultrasonic sensor device shown in the first embodiment, the detailed description of the common parts will be omitted below, and different parts will be described mainly. . In addition, the same code | symbol shall be provided to the element same as the element shown in 1st Embodiment.

  In the first embodiment, the presence or absence of abnormality of the ultrasonic sensor device 10 (ultrasonic sensor 100) can be determined, but it cannot be determined whether there is an abnormality on the transmission side or the reception side. On the other hand, in the present embodiment, the ECU 20 is in an abnormal position (transmission side) based on the attenuation waveform (in other words, the reverberation of the transmission wave) of the output signal (transmission wave) of the piezoelectric vibrator 110a for transmission. And which side is abnormal on the receiving side).

  First, the attenuation waveform (reverberation) of the output signal (transmission wave) of the transmission piezoelectric vibrator 110a will be described. As shown in FIG. 9, for example, when a self-diagnosis drive signal is input to the transmission piezoelectric vibrator 110 a from the drive signal generation unit 30, the piezoelectric vibrator 110 a vibrates and transmits the bottom surface 121 of the housing 120. A transmission wave is output to the outside of the vehicle. Even if the self-diagnosis drive signal is stopped (that is, transmission vibration of the piezoelectric vibrator 110a is stopped), the bottom surface portion 121 that is a diaphragm vibrates for a while. This is called reverberation, and the output of the transmission wave is longer than the self-diagnosis drive signal by the reverberation time as shown in FIG. In the following, it is assumed that the output signal of the transmission wave shown in FIG. 9 is in a state in which there is no abnormality in the ultrasonic sensor 100a on the transmission side.

  Next, the principle of determining an abnormal position using reverberation will be described with reference to FIG. For example, when there is an abnormality in the ultrasonic sensor 100b on the reception side (piezoelectric vibrator 110b and tube portion 132b), the output signal of the transmission wave is not affected by the abnormality, so the output signal of the transmission wave is shown in FIG. As shown. That is, the attenuation waveform of the output signal of the transmission wave is almost the same as the reference state shown in FIG. 9. For example, the reverberation time is also substantially the same as the reverberation time of the reference state (corresponding to the second reference value described in the claims). It becomes equal value.

  On the other hand, in the ultrasonic sensor 100b on the receiving side, when there is an abnormality in the tube part 132a (for example, the intrusion of the foreign matter 6 or the damage to the tube part 132a), the piezoelectric vibrator 110a receives the ultrasonic wave reflected at the abnormal part. Will be. Therefore, the attenuation waveform of the output signal of the transmission wave is different from the reference state shown in FIG. 9. For example, the reverberation time is longer than the reverberation time of the reference state (corresponding to the second reference value described in the claims). become longer. In this way, an abnormal position can be determined based on the attenuation waveform of the output signal of the transmission wave.

  Various methods for determining the position of the ultrasonic sensor device 10 that are abnormal based on the attenuation waveform of the output signal of the transmission wave are conceivable. One example will be described with reference to FIG. For example, this process is executed subsequent to the abnormality presence / absence determination process (see FIG. 7) shown in the first embodiment. Steps S10 to S40 are the same as the determination process of FIG. 7 shown in the first embodiment. In S20, when the sneak wave W2 is not detected, it is presumed that at least one of the piezoelectric vibrators 110a and 110b has failed or at least one of the tube portions 132a and 132b is blocked. Therefore, the ECU 20 determines that the ultrasonic sensor device 10 is in an abnormal state, and outputs a notification instruction signal to the notification unit 50. And the alerting | reporting part 50 alert | reports to a passenger | crew by a warning sound and the display on a monitor (S110), and a self-diagnosis process is complete | finished.

  In S40, when the detected peak value substantially matches the reference value, the ECU 20 determines that the piezoelectric vibrator 110 (110a, 110b) and the pipe portion 132 (132a, 132b) are not abnormal, and the self-diagnosis process is performed. End.

  In S40, when the detected peak value is different from the reference value, the ECU 20 determines that the ultrasonic sensor device 10 is in an abnormal state, and again instructs the oscillation circuit 31 of the drive signal generation unit 30 to generate a drive signal for self-diagnosis. Put out. Receiving this, the drive signal generation unit 30 outputs a self-diagnosis drive signal to the transmission piezoelectric vibrator 110a, and the piezoelectric vibrator 110a is transmitted and vibrated to output a transmission wave (ultrasonic wave).

  The piezoelectric vibrator 110a detects the output signal of the transmission wave at this time (S120), and the ECU 20 detects the reverberation time based on the output signal of the transmission wave (S130). Then, the ECU 20 determines whether or not the detected reverberation time is longer than a reference value (second reference value) stored in advance in the memory (S140).

  When the detected reverberation time is less than or equal to the reference value, the ECU 20 determines that there is no abnormality in the ultrasonic sensor 100a on the transmission side, and thereby there is an abnormality in the ultrasonic sensor 100b on the reception side (S150). Then, a notification instruction signal is output to the notification unit 50, and the notification unit 50 notifies the occupant with an alarm sound and a display on the monitor (S160), and the self-diagnosis process ends.

  When the detected reverberation time is longer than the reference value, the ECU 20 determines that there is an abnormality in the transmitting-side ultrasonic sensor 100a (pipe portion 132a) (S170). Then, a notification instruction signal is output to the notification unit 50, and the notification unit 50 notifies the occupant with an alarm sound and a display on the monitor (S180), and the self-diagnosis process ends. For example, in the notification in S110, S160, and S180, the respective notification sounds and displays may be changed. In the case of S160 and S180, since an abnormal position is also determined, the information may be included.

  As described above, according to the ultrasonic sensor device 10 shown in the present embodiment, the position of the abnormality of the ultrasonic sensor device 10 (ultrasonic sensor 100) is determined based on the attenuation waveform (reverberation time) of the output signal of the transmission wave. can do.

  In the present embodiment, after the comparison determination in S40, when the detected peak value is different from the reference value, a self-diagnosis drive signal generation instruction is issued again to cause the transmission piezoelectric vibrator 110a to transmit and vibrate. An example of detecting the output signal of the transmission wave in S120 is shown. However, an output signal of a transmission wave for generating the sneak wave W1 may be detected before the sneak wave W1 is detected in S10.

  Further, the determination process shown in the present embodiment is not limited to the combination with the determination process shown in FIG. 7 of the first embodiment. For example, it can be combined with the determination process shown in FIG. 8 of the first embodiment. Further, the determination of the presence / absence of abnormality of the ultrasonic sensor device 10 and the determination of the abnormal position are combined based on the attenuation waveform of the output signal of the transmission wave without going through the determination process using the sneak wave W2 shown in the first embodiment. Can be executed. In this case, for example, the processing of S110 to S180 shown in FIG. 11 may be executed. It should be noted that even when the output signal of the transmission wave is not detected, it is preferable to determine that it is abnormal. However, with such a configuration, it is only possible to determine whether there is an abnormality on the side where the piezoelectric vibrator 110 has a transmission function and an abnormal position, but whether there is an abnormality on the side where the piezoelectric vibrator 110 has only a reception function. The position cannot be determined. Therefore, when all the piezoelectric vibrators 110 have a transmission function, it is preferable to execute the determination of the presence / absence of abnormality of the ultrasonic sensor device 10 and the determination of the abnormal position based on the attenuation waveform of the output signal of the transmission wave. .

  Also in the present embodiment, as the simplest example, the ultrasonic sensor 100 includes, as the piezoelectric vibrator 110, one piezoelectric vibrator 110a dedicated for transmission and one piezoelectric vibrator 110b dedicated for reception. Indicated. However, the configuration of the ultrasonic sensor 100 is not limited to the above example. For example, it may be configured to have a plurality of piezoelectric vibrators 110 (only for transmission or for both transmission and reception) having a transmission function. In this case, for example, as shown in FIG. 12, in S120, the ECU 20 selects one of the plurality of piezoelectric vibrators 110 having a transmission function and vibrates it to detect an output signal of the transmission wave. Then, the ECU 20 detects the reverberation time based on the output signal of the transmission wave (S130), and determines whether or not the detected reverberation time is longer than a reference value (second reference value) stored in advance in the memory. Determine (S140). As a result, when the detected reverberation time is equal to or less than the reference value, it is determined that there is no abnormality in the tube portion 132 in which the selected piezoelectric vibrator 110 is arranged, and another piezoelectric vibrator 110 having a transmission function. Switch to transmit vibration. These S120 to 145 are repeatedly executed by sequentially switching the piezoelectric vibrator 110 until it is determined in S140 that the reverberation time is longer than the reference value. As described above, even in a configuration having a plurality of piezoelectric vibrators 110 having a transmission function, an abnormal position can be determined. FIG. 12 is a flowchart showing a modification.

  In S120, all the piezoelectric vibrators 110 having a transmission function are vibrated, and in S130, the reverberation time of each transmission wave is detected, and in S140, each reverberation time is compared with a reference value. Also good. In this case, it can be determined that there is an abnormality even if there is an abnormality in all the tube portions 132 in which the piezoelectric vibrator 110 having the transmission function is arranged. In addition, for example, as shown in FIG. 13, in S120, all the piezoelectric vibrators 110 having a transmission function are vibrated, and in S130, the ECU 20 detects the reverberation time of each transmission wave, and in S141, Each reverberation time may be compared with each other. In this case, if there is one having a reverberation time longer than at least one of the other, in S171, it is determined that there is an abnormality in the tube portion 132 in which the piezoelectric vibrator 110 having the long reverberation time is arranged, The notification with the information is executed in S180. When all the reverberation times are equal, there is an abnormality in all the tube parts 132 or an abnormality in a part different from the tube part 132 (for example, failure of all the piezoelectric vibrators 110 having a transmission function). What is necessary is just to alert | report in S180. In this case, since the reverberation times of the output signals of the plurality of piezoelectric vibrators 110 having the transmission function are compared with each other, the influence of the change in the measurement conditions (for example, the change in the reverberation time due to the temperature) can be offset. FIG. 13 is a flowchart showing a modification.

  The preferred embodiments of the present invention have been described above. However, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention.

  In this embodiment, the example in which the ultrasonic sensor 100 is attached to the bumper 2 of the vehicle as a moving body is shown. However, the moving body is not limited to the vehicle, and the attached portion is not limited to the bumper 2. Even a vehicle can be attached to a body, for example.

  Further, the configuration of the ultrasonic sensor 100 is not limited to the configuration shown in this embodiment (the number, arrangement, shape, and transmission / reception function of the piezoelectric vibrator 110 and the tube portion 132). It suffices to have at least two piezoelectric vibrators 110 (two pipe portions 132), of which at least one has a transmission function and at least one has a reception function. In addition, one piezoelectric vibrator 110 is fixed to one end portion of the tube portion 132 (waveguide) so that at least one of transmission and reception is possible, and each tube portion 132 has a reflected wave and a sneak wave. Any arrangement may be used as long as it can be detected. In addition, the tube portion 132 may be configured as an independent waveguide.

1 is a configuration diagram illustrating an overall configuration of an ultrasonic sensor device according to a first embodiment of the present invention. It is sectional drawing which shows schematic structure of an ultrasonic sensor among ultrasonic sensor apparatuses. It is the top view which looked at FIG. 2 from the outer surface side of the moving body. FIG. 3 is an enlarged cross-sectional view around the housing in FIG. 2. It is a figure for demonstrating a reflected wave and a sneak wave. It is a figure which shows the change of the received signal accompanying abnormality presence, (a) is a state without abnormality and there is an obstacle, (b) is a state without abnormality and there is no obstacle, (c) is abnormal and there is an obstacle. It is a figure which shows the state of. It is a flowchart which shows an example of the process which determines the abnormality presence or absence of an ultrasonic sensor apparatus. It is a flowchart which shows a modification. It is a figure for demonstrating reverberation. It is a figure which shows the change of a transmission wave, (a) is a figure which shows the case where there is abnormality on the receiving side, and (b) is the case where there is abnormality on the transmission side. In 2nd Embodiment, it is a flowchart which shows the process which determines the abnormality presence or absence of an ultrasonic sensor apparatus. It is a flowchart which shows a modification. It is a flowchart which shows a modification.

Explanation of symbols

1 ... Obstacle (reflective object)
6 ... Foreign object 10 ... Ultrasonic sensor device 20 ... ECU
DESCRIPTION OF SYMBOLS 100 ... Ultrasonic sensor 100a ... Transmission ultrasonic sensor 100b ... Reception ultrasonic sensor 110 ... Piezoelectric vibrator 110a ... Transmission piezoelectric vibrator 110b ... Reception Piezoelectric vibrator 132 ... tube part (waveguide)
132a: Transmitting tube 132b: Receiving tube

Claims (10)

A plurality of waveguides;
At least one transmitting ultrasonic element that transmits ultrasonic waves through the waveguide as an ultrasonic element respectively disposed at one end of the waveguide, and receiving ultrasonic waves; At least one receiving ultrasonic element that outputs a reception signal corresponding to the intensity of the ultrasonic wave;
From the end opposite to the element arrangement side of the waveguide on which the transmission ultrasonic element is arranged, it propagates by directly wrapping around the waveguide on which the reception ultrasonic element is arranged in the vicinity. An ultrasonic sensor device comprising: determination means for determining presence / absence of abnormality of at least one of the ultrasonic element and the waveguide based on the reception signal of the sneak wave. A storage means in which a peak value of a received signal due to the sneak wave in a state where there is no abnormality in the waveguide through which the sneak wave propagates is stored as a first reference value,
The determination unit determines that the abnormality is detected when the sneak wave is not detected or when the sneak wave is detected and the peak value of the received signal is different from the first reference value of the storage unit. The ultrasonic sensor device according to claim 1.   The ultrasonic sensor device according to claim 1, wherein the determination unit determines an abnormal position based on an attenuation waveform of an output signal of the transmission ultrasonic element. In the storage means, the reverberation time of the output signal of the transmission ultrasonic element in a state where there is no abnormality in the waveguide in which the transmission ultrasonic element is arranged is stored as a second reference value,
When the peak value of the received signal is different from the first reference value of the storage means, the determination means is when the reverberation time of the output signal of the transmitting ultrasonic element is longer than the second reference value of the storage means 4. The ultrasonic sensor device according to claim 3, wherein it is determined that the waveguide in which the transmitting ultrasonic element is disposed is abnormal. Having a plurality of ultrasonic elements for transmission,
When the peak value of the received signal is different from the first reference value of the storage unit, the determination unit compares the reverberation times of the output signals of the plurality of transmitting ultrasonic elements with each other to obtain at least one reverberation time. The ultrasonic sensor device according to claim 3, wherein when the reverberation time is longer than the other, the waveguide having a long reverberation time is determined to be abnormal. A waveguide;
As an ultrasonic element disposed at one end of the waveguide, at least one transmission ultrasonic element that transmits ultrasonic waves through the waveguide, and receiving ultrasonic waves, At least one receiving ultrasonic element that outputs a reception signal corresponding to the intensity of the ultrasonic wave;
An ultrasonic sensor device comprising: determination means for determining at least whether the waveguide is abnormal based on an attenuation waveform of an output signal of the transmitting ultrasonic element. A plurality of the waveguides, the ultrasonic elements are respectively disposed at one end of the waveguide,
In the storage means, the reverberation time of the output signal of the transmission ultrasonic element in a state where there is no abnormality in the waveguide in which the transmission ultrasonic element is arranged is stored as a second reference value,
When the reverberation time of the output signal of the transmission ultrasonic element is longer than the second reference value of the storage means, the determination unit is abnormal in the waveguide in which the transmission ultrasonic element is disposed. The ultrasonic sensor device according to claim 6, wherein A plurality of the waveguides, the ultrasonic elements are respectively disposed at one end of the waveguide,
Having a plurality of ultrasonic elements for transmission,
The determination unit compares the reverberation times of the output signals of the plurality of transmitting ultrasonic elements with each other, and when at least one reverberation time is longer than the other reverberation times, the waveguide having a long reverberation time is The ultrasonic sensor device according to claim 6, wherein the ultrasonic sensor device is determined to be abnormal.   The ultrasonic sensor device according to any one of claims 1 to 8, further comprising a notification unit that notifies the occupant that the vehicle is in an abnormal state based on a determination result by the determination unit. In the waveguide, the end opposite to the element arrangement side is exposed to the outside through a through hole formed in the attached portion of the moving body,
The ultrasonic sensor device according to claim 1, wherein the ultrasonic element is disposed inside the moving body.

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