WO2012147284A1 - Moving object detection device - Google Patents

Moving object detection device Download PDF

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Publication number
WO2012147284A1
WO2012147284A1 PCT/JP2012/002396 JP2012002396W WO2012147284A1 WO 2012147284 A1 WO2012147284 A1 WO 2012147284A1 JP 2012002396 W JP2012002396 W JP 2012002396W WO 2012147284 A1 WO2012147284 A1 WO 2012147284A1
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WO
WIPO (PCT)
Prior art keywords
ultrasonic
moving object
phase difference
receivers
ultrasonic receivers
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PCT/JP2012/002396
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French (fr)
Japanese (ja)
Inventor
将之 本田
祐樹 前田
隆昭 浅田
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株式会社村田製作所
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Publication of WO2012147284A1 publication Critical patent/WO2012147284A1/en

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    • 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
    • G01S7/52—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S15/00
    • G01S7/521—Constructional features
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S15/00—Systems using the reflection or reradiation of acoustic waves, e.g. sonar systems
    • G01S15/02—Systems using the reflection or reradiation of acoustic waves, e.g. sonar systems using reflection of acoustic waves
    • G01S15/06—Systems determining the position data of a target
    • G01S15/42—Simultaneous measurement of distance and other co-ordinates

Definitions

  • the present invention relates to a moving object detection apparatus that detects the position of a moving object using ultrasonic waves.
  • Patent Document 1 discloses a vehicle position detection device that detects an angle between a position marker installed on a road surface and a host vehicle from a Doppler signal obtained from a reflected wave of transmitted radio waves (or ultrasonic waves). ing.
  • This vehicle position detection device has a Doppler detection sensor mounted on the vehicle.
  • the Doppler detection sensor transmits a radio wave having a frequency f 0 as a search wave to a position marker previously set on the road surface.
  • the reflected wave of frequency fi received by the antenna is input to the mixer together with a part of the transmission signal and mixed.
  • the relative speed extracting means calculates a relative speed V ′ with respect to the position marker from the following equation (1).
  • fd 2 ⁇ f 0 ⁇ V ′ / c
  • c is the speed of light (3 ⁇ 10 8 (m / sec))
  • the position detecting means detects the traveling speed V of the vehicle with a vehicle speed sensor, and obtains the angle ⁇ between the traveling direction of the vehicle and the position marker according to the following equation (2) from the traveling speed V and the relative speed V ′.
  • V ′ V cos ⁇ (2)
  • the angle ⁇ between the vehicle and the position marker is obtained based on the vehicle speed V and the relative speed V ′ calculated from the Doppler signal.
  • the angle ⁇ between the vehicle and the position marker cannot be detected unless the vehicle speed V is known. That is, in order to detect the angle ⁇ with the position marker, a vehicle speed sensor or the like for detecting the vehicle speed V is required, so that the sensor configuration is complicated and the apparatus may be increased in size. Therefore, there has been a demand for a technique that can be applied to, for example, a small portable device with a simpler sensor configuration (ie, without detecting the speed of the host vehicle).
  • the present invention has been made to solve the above-described problems, and in a moving object detection apparatus that detects the position of a moving object using ultrasonic waves, a movement that can be further reduced in size with a simple sensor configuration.
  • An object of the present invention is to provide an object detection device.
  • a moving object detection apparatus includes an ultrasonic transmitter that transmits ultrasonic waves, and a plurality of ultrasonic receivers that receive reflected waves that are transmitted from the ultrasonic transmitter and reflected back to the moving object.
  • a beat extracting means for extracting a beat signal from reflected waves received by each of the plurality of ultrasonic receivers, a phase difference obtaining means for obtaining a phase difference between the plurality of beat signals extracted by the beat extracting means, and a phase difference obtaining Position detecting means for detecting the position of the moving object based on the phase difference of the plurality of beat signals obtained by the means, and the distance between the plurality of ultrasonic receivers is transmitted as a desired detectable angle.
  • the phase difference of the ultrasonic waves reaching each of the plurality of ultrasonic receivers is set to be 180 ° or less according to the wavelength of the ultrasonic wave.
  • the moving object detection device of the present invention receives the reflected wave reflected by the moving object (that is, the reflected wave whose frequency is shifted by the Doppler shift) from the plurality of ultrasonic receivers.
  • a beat signal is extracted for each of the plurality of ultrasonic receivers, and the position of the moving object is detected based on the phase difference of the extracted beat signals.
  • the distance between the plurality of ultrasonic receivers is such that the phase difference of the ultrasonic waves reaching each of the plurality of ultrasonic receivers is 180 ° based on the desired detectable angle and the wavelength of the transmitted ultrasonic waves.
  • the position of the moving object can be detected from the phase difference of the beat signals.
  • the position of the moving object can be detected without knowing the speed of the own device, and thus a simpler sensor configuration (that is, ultrasonic transmission).
  • the position of the moving object can be detected by only the machine and the ultrasonic receiver), and the apparatus can be further downsized.
  • the distance between the plurality of ultrasonic receivers is set based on the following equation (3).
  • Distance between ultrasonic receivers L ( ⁇ / 2) / sin ( ⁇ / 2) (3) Where ⁇ is the wavelength of the transmitted ultrasonic wave and ⁇ is the desired detectable angle
  • each of the plurality of ultrasonic receivers is arranged so that the distance from the ultrasonic transmitter is equal.
  • the moving object detection apparatus includes three ultrasonic receivers, and the three ultrasonic receivers are arranged so that the intervals between them are all equal.
  • the intervals between the three ultrasonic receivers are all equal, the relationship between the detectable angle and the distance between the receivers does not differ in each ultrasonic receiver. Therefore, the same position detection algorithm can be applied. Therefore, the processing load such as calculation is reduced, and the position of the moving object can be detected with higher accuracy. Further, by providing three ultrasonic receivers, it is possible to detect the position of a moving object in three dimensions.
  • a moving object detection apparatus that detects the position of a moving object using ultrasonic waves can be further downsized with a simple sensor configuration.
  • FIG. 1 is a block diagram illustrating a configuration of the moving object detection device 1.
  • FIG. 2 is a diagram for explaining the relationship between the detectable angle and the distance between the ultrasonic receivers.
  • FIG. 3 is a graph showing the relationship between the detectable angle and the distance between the ultrasonic receivers.
  • the moving object detection device 1 transmits ultrasonic waves, receives reflected waves reflected by the moving object by a plurality (two) of ultrasonic receivers 20 and 21, and beats by Doppler shift from the received reflected waves. A signal (frequency shift component) is extracted, and the position (angle) of the moving object is detected based on the phase difference of the beat signal.
  • the moving object detection apparatus 1 drives the ultrasonic transmitter 10 that continuously transmits ultrasonic waves, the two ultrasonic receivers 20 and 21 that receive ultrasonic waves, and the ultrasonic transmitter 10.
  • a signal processing unit 30 for detecting the position of the moving object from the received signals received by the ultrasonic receivers 20 and 21.
  • the signal processing unit 30 includes a transmission signal generation unit 31, a drive circuit 32, a filter / amplification unit 33, a mixer 34, an A / D converter 35, an A / D value acquisition unit 36, a phase difference acquisition unit 37, and a moving object position.
  • a detection unit 38 is provided. Hereinafter, each component will be described in detail.
  • the ultrasonic transmitter 10 is connected to the signal processing unit 30 via the wiring 25.
  • the ultrasonic transmitter 10 drives a piezoelectric element (piezo element) in accordance with an ultrasonic drive signal input from the signal processing unit 30, and continuously transmits, for example, an ultrasonic pulse (ultrasonic signal) of 40 kHz. .
  • the two ultrasonic receivers 20 and 21 are transmitted from the ultrasonic transmitter 10 and reflected from the moving object (and / or a stationary object) and returned directly, and directly from the ultrasonic transmitter 10. Receiving ultrasound to reach.
  • Each of the ultrasonic receivers 20 and 21 is connected to the signal processing unit 30 via the wirings 26 and 26, and the reception signal output from each of the ultrasonic receivers 20 and 21 is input to the signal processing unit 30. .
  • the distance L between the two ultrasonic receivers 20 and 21 shown in FIG. 2 depends on the required detectable angle (that is, the desired detectable angle) and the wavelength of the transmitted ultrasonic wave.
  • the phase difference when the ultrasonic wave transmitted from an arbitrary point on the outer edge that defines the detectable region reaches each of the two ultrasonic receivers 20 and 21 is set to be 180 ° or less. In other words, the difference in the lengths of the straight lines connecting any point on the outer edge that defines the detectable region and each of the two ultrasonic receivers 20 and 21 is less than or equal to “ultrasonic wavelength ⁇ / 2”. Is set.
  • the distance L between the two ultrasonic receivers 20 and 21 is set based on the following equation (4).
  • Distance L ( ⁇ / 2) / sin ( ⁇ / 2) (4)
  • ⁇ is the wavelength of the transmitted ultrasonic wave and ⁇ is the desired detectable angle
  • the distance L between the ultrasonic receivers 20 and 21 is ⁇ / 2. Therefore, for example, when using a 40 kHz ultrasonic wave, the distance L between the ultrasonic receivers 20 and 21 is set to 4.25 mm or less. Similarly, when the detectable angle is 120 °, the distance L is ⁇ / ⁇ 3 (4.9 mm), and when the detectable angle is 90 °, the distance L is ⁇ / ⁇ 2 (6.0 mm). ), When the detectable angle is 60 °, the distance L is ⁇ (8.5 mm), and when the detectable angle is 30 °, the distance L is 2 ⁇ (17.0 mm).
  • FIG. 3 shows the relationship between the detectable angle and the distance between the ultrasonic receivers.
  • the distance L between the ultrasonic receivers 20 and 21 decreases.
  • the two ultrasonic receivers 20 and 21 are installed side by side within a distance determined according to a desired detectable angle shown in the graph of FIG.
  • the ultrasonic transmitter 10 is disposed at the center of a straight line connecting the two ultrasonic receivers 20 and 21 as shown in FIG.
  • positioning of the ultrasonic transmitter 10 is not restricted to this example, It can arrange
  • the signal processing unit 30 supplies an ultrasonic drive signal to the ultrasonic transmitter 10 to drive the ultrasonic transmitter 10 and processes reflected waves (received signals) received by the ultrasonic receivers 20 and 21. To detect the position of the moving object.
  • the signal processing unit 30 includes a drive circuit 32 as an output interface, a filter / amplifier 33 as an input interface, a mixer 34, and an A / D converter 35, and the filter / amplifier 33, mixer 34, A / D.
  • a CPU that performs signal processing and the like on a received signal input via the converter 35, a ROM that stores programs and data for causing the CPU to execute each process, and various data such as calculation results are temporarily stored. It is composed of a RAM for storing.
  • a program stored in the ROM is executed by the CPU, so that the transmission signal generation unit 31, the A / D value acquisition unit 36, the phase difference acquisition unit 37, and the moving object position detection unit 38 Each function is realized.
  • the CPU for example, an ASIC, FPGA, DSP, or the like may be used.
  • the transmission signal generation unit 31 generates an ultrasonic drive signal having an ultrasonic frequency (40 kHz in the present embodiment) and outputs the ultrasonic drive signal to the drive circuit 32.
  • the drive circuit 32 amplifies the ultrasonic drive signal input from the transmission signal generation unit 31 and supplies the amplified ultrasonic drive signal to the ultrasonic transmitter 10 through the wiring 25. As described above, the ultrasonic transmitter 10 is driven by the ultrasonic drive signal and transmits ultrasonic waves.
  • the filter / amplifier 33 is configured by an amplifier circuit using, for example, an operational amplifier, a low-pass filter, a band-pass filter, or the like, and is received by the ultrasonic receivers 20 and 21 and received via the wiring 26. After amplifying the signal, a signal (noise) other than the desired signal is removed. The received signal that has been amplified by the filter / amplifier 33 and from which noise has been removed is output to the mixer 34.
  • the mixer 34 mixes (mixes) the reception signals (reflected waves) received by the two ultrasonic receivers 20 and 21 and the ultrasonic drive signals (transmission waves) input from the transmission signal generation unit 31. To extract the beat signal. That is, the mixer 34 functions as a beat extraction unit described in the claims.
  • the received waves received by the ultrasonic receivers 20 and 21 include a direct wave directly reaching from the ultrasonic transmitter 10 and a reflected wave reflected by the moving object. The frequency is shifted by Doppler shift.
  • a beat signal Doppler frequency component indicated by a one-dot chain line in FIG. 5 is extracted.
  • the beat signal extracted by the mixer 34 is output to the A / D converter 35.
  • the A / D converter 35 is an analog-digital converter that converts an analog signal into digital data, and converts a beat signal (analog signal) input from the mixer 34 into digital data.
  • the A / D value acquisition unit 36 controls the operation of the A / D converter 35 and acquires the beat signal converted into digital data by the A / D converter 35.
  • the digital data acquired by the A / D value acquisition unit 36 is output to the phase difference acquisition unit 37.
  • the phase difference acquisition unit 37 compares the phases of two beat signals extracted by the mixer 34 and read via the A / D value acquisition unit 36 to obtain a phase difference (see FIG. 5). That is, the phase difference acquisition unit 37 functions as a phase difference acquisition unit described in the claims.
  • the acquired phase difference of the beat signal is output to the moving object position detector 38.
  • the moving object position detection unit 38 detects the two-dimensional position (relative angle with the moving object) of the moving object based on the phase difference between the two systems of beat signals acquired by the phase difference acquisition unit 37. That is, the moving body position detection unit 38 functions as a position detection unit described in the claims.
  • the phase of the beat signal extracted from the received signal of the ultrasonic receiver 20 located on the left side of the drawing in FIG. 2 is the received signal of the ultrasonic receiver 21 located on the right side of the drawing.
  • the phase of the beat signal extracted from is delayed. Therefore, in this case, it is detected that a moving object exists on the left side of FIG.
  • the angle with the moving object is detected according to the magnitude of the phase difference. Note that the position of the moving object (angle with the moving object) detected by the moving object position detection unit 38 is output to an external device.
  • FIG. 6 is a flowchart illustrating a processing procedure of the moving object detection process performed by the moving object detection device 1.
  • a continuous ultrasonic drive signal is generated and output.
  • the output ultrasonic drive signal is amplified by the drive circuit 32 and supplied to the ultrasonic transmitter 10.
  • the ultrasonic transmitter 10 is driven by the supplied ultrasonic drive signal and continuously transmits the ultrasonic signal (step S100).
  • the ultrasonic signal transmitted from the ultrasonic transmitter 10 in step S100 propagates through space and is reflected by a moving object (and / or a stationary object).
  • the reflected ultrasonic signal returns to the space and is received by the ultrasonic receivers 20 and 21 (step S102).
  • the reflected waves received by the ultrasonic receivers 20 and 21 in step S102 are amplified by the filter / amplifier 33 and noise is removed, and then the ultrasonic waves input from the transmission signal generator 31 in the mixer 34 are obtained.
  • the beat signal is extracted by mixing with the drive signal (transmission wave) (step S104).
  • the beat signal extracted in step S104 is converted into digital data by the A / D converter 35 and read into the phase difference acquisition unit 37 via the A / D value acquisition unit 36. Then, the phase difference acquisition unit 37 compares the phases of the two beat signals to obtain the phase difference (see FIG. 5) (step S106).
  • step S108 the two-dimensional position (angle with respect to the moving object) of the moving object is detected based on the phase difference between the two beat signals obtained in step S106. Since the method of detecting the two-dimensional position of the moving object is as described above, detailed description thereof is omitted here. Note that the position of the moving object detected in step S108 is output to an external device.
  • two ultrasonic waves are overlapped with an ultrasonic wave directly reaching from the ultrasonic transmitter 10 and a reflected wave reflected by a moving object (that is, a reflected wave whose frequency is shifted by Doppler shift). It is received by the sound wave receivers 20 and 21.
  • a beat signal is extracted for each of the two ultrasonic receivers 20 and 21, and the position of the moving object (angle with respect to the moving object) is detected based on the phase difference between the extracted beat signals.
  • the distance between the two ultrasonic receivers 20 and 21 is an ultrasonic wave reaching each of the two ultrasonic receivers 20 and 21 based on the desired detectable angle and the wavelength of the transmitted ultrasonic waves.
  • the position of the moving object can be detected from the phase difference of the beat signal.
  • the position of a moving object can be detected without knowing the speed of the own device, and thus a simpler sensor configuration (that is, the ultrasonic transmitter 10 and the ultrasonic wave).
  • the position of the moving object can be detected by only the receivers 20 and 21), and the apparatus can be further downsized. Further, according to the present embodiment, it is possible to detect only a moving object without detecting a stationary object.
  • each of the two ultrasonic receivers 20 and 21 is arranged at a desired detectable angle.
  • the phase difference of the reaching ultrasonic waves can be 180 ° or less.
  • each of the ultrasonic transmitter 10 and the two ultrasonic receivers 20 and 21 uses a short distance (for example, 40 KHz ultrasonic waves and 8.5 mm when the desired detectable angle is 60 °).
  • the apparatus can be reduced in size.
  • the distance between the two ultrasonic receivers 20 and 21 and the ultrasonic transmitter 10 is equal, the distance between the ultrasonic receivers 20 and 21 and the ultrasonic transmitter 10 is different. Correction of the phase shift of the beat signal caused by this is not necessary. Therefore, it is possible to reduce the processing load such as calculation and to detect the position of the moving object with higher accuracy.
  • the moving object detection apparatus 1 includes two ultrasonic receivers 20 and 21 and detects the two-dimensional position of the moving object based on the phase difference between the two systems of beat signals. .
  • it can also be set as the structure which has the three ultrasonic receivers 20, 21, and 22 and detects the three-dimensional position of a moving object from the phase difference of each of 3 types of beat signals.
  • FIG. 7 is a block diagram illustrating a configuration of the moving object detection device 2.
  • the same or equivalent components as those in the first embodiment are denoted by the same reference numerals.
  • the moving object detection device 2 includes an ultrasonic receiver 22 and a filter / amplifier 33 that performs processing of a received signal received by the ultrasonic receiver 22.
  • the moving object detection apparatus 1 is different in that it further includes a mixer 34 and an A / D converter 35.
  • the phase difference acquisition unit 37A is different from the phase difference acquisition unit 37 described above in that the phase difference is acquired by comparing the phases of the three beat signals.
  • the moving object position detection unit 38A is different from the moving object position detection unit 38 described above in that it detects the three-dimensional position of the moving object based on the phase difference between the three beat signals.
  • these different points will be mainly described.
  • Other configurations are the same as or similar to those of the moving object detection device 1 described above, and thus detailed description thereof is omitted here.
  • the ultrasonic receiver 22 is transmitted from the ultrasonic transmitter 10 and is reflected by a moving object (and / or a stationary object) and returns to the reflected wave, and The ultrasonic waves that reach directly from the ultrasonic transmitter 10 are received.
  • the ultrasonic receiver 22 is connected to the signal processing unit 30A via the wiring 26, and the reception signal output from the ultrasonic receiver 22 is input to the signal processing unit 30A.
  • the three ultrasonic receivers 20, 21, and 22 are arranged so that their intervals are all equal. 8 shows the arrangement of the ultrasonic transmitter 10 and the three ultrasonic receivers 20, 21, 22 constituting the moving object detection apparatus 2 (the ultrasonic transmitter 10 and the ultrasonic receivers 20, 21, 22).
  • FIG. 8 shows the arrangement of the ultrasonic transmitter 10 and the three ultrasonic receivers 20, 21, 22 constituting the moving object detection apparatus 2 (the ultrasonic transmitter 10 and the ultrasonic receivers 20, 21, 22).
  • the distance from the adjacent ultrasonic receiver is set based on the above-described equation (4). That is, the three ultrasonic receivers 20, 21, and 22 are installed such that the distance between them is within a distance determined according to the desired detectable angle shown in the graph of FIG.
  • the ultrasonic transmitter 10 is preferably arranged so that the intervals between the three ultrasonic receivers 20, 21, and 22 are equal.
  • the arrangement of the ultrasonic transmitter 10 is not limited to this example, and can be arranged at an arbitrary position. That is, for example, as shown in FIG. 9, the ultrasonic transmitter 10 and the three ultrasonic receivers 20, 21, and 22 may be arranged so as to be located at each vertex of a square.
  • FIG. 9 shows another example of the arrangement of the ultrasonic transmitter 10 and the three ultrasonic receivers 20, 21, 22 constituting the moving object detection apparatus 2 (the ultrasonic transmitter 10 and each ultrasonic receiver). 20, 21, and 22 are different from each other). If it arrange
  • the phase difference acquisition unit 37A compares the phases of the three beat signals extracted by the mixer 34 and read through the A / D value acquisition unit 36 to obtain a phase difference (see FIG. 10). That is, the phase difference acquisition unit 37A also functions as a phase difference acquisition unit described in the claims. The phase difference of the acquired beat signal is output to the moving object position detection unit 38A.
  • the moving object position detection unit 38A detects the three-dimensional position of the moving object (relative angle with the moving object) based on the phase difference of the three systems of beat signals obtained by the phase difference acquisition unit 37A. That is, the moving body position detection unit 38A also functions as the position detection unit described in the claims.
  • the phase of the beat signal extracted from the reception signal of the ultrasonic receiver 20 located on the lower left side in FIG. 8 is the reception of the ultrasonic receiver 22 located on the upper side of the figure. It is behind the phase of the beat signal extracted from the signal.
  • the beat signal extracted from the received signal of the ultrasonic receiver 20 located on the lower left side of the drawing is the phase of the beat signal extracted from the received signal of the ultrasonic receiver 21 located on the lower right side of the drawing in FIG.
  • the three ultrasonic receivers 20, 21, 22 can be used to detect the position of the moving object in three dimensions. Further, according to the present embodiment, the three ultrasonic receivers 20, 21, and 22 are all equal in interval, so that the detectable angle and the inter-receiver distance in each of the ultrasonic receivers 20, 21, and 22. The relationship with is unchanged. Therefore, the same position detection algorithm can be applied. Therefore, it is possible to reduce the processing load such as calculation and to detect the position of the moving object with higher accuracy.
  • the present invention is not limited to the above-described embodiments, and various modifications can be made.
  • the arrangement of the ultrasonic transmitter 10 and the ultrasonic receivers 20, 21, and 22 and the frequency of the ultrasonic waves to be used are not limited to the above-described embodiment, and for example, required specifications for the moving object detection devices 1 and 2 Can be set arbitrarily.
  • the ultrasonic transmitter 10 and the ultrasonic receivers 20, 21, and 22 were arrange
  • the moving object detection devices 1 and 2 can be used by being attached to various devices.
  • the moving object detection devices 1 and 2 may be attached to a bumper of an automobile to detect the presence / absence / position of a pedestrian and emit a warning sound from a speaker according to the detection result. If it does in this way, a contact accident with a pedestrian can be reduced. In particular, a high effect can be expected in EVs (electric cars and electric motorcycles) where the running sound is quiet.
  • the moving object detection devices 1 and 2 are attached to a TV or personal computer monitor, and the presence / absence / position of a person is detected, and the TV / monitor is turned on / off according to the presence / absence of a person. Depending on the position, surround and volume may be adjusted. At that time, since the moving object detection devices 1 and 2 can detect only a moving person, for example, erroneous detection due to a stationary object such as a table or a chair arranged in the vicinity may occur. Absent.

Abstract

The present invention provides a moving object detection device that detects the position of a moving object using ultrasonic waves, that has a simple sensor structure and that can be made more compact. A moving object detection device (1) is provided with the following: an ultrasonic wave transmitter (10) that transmits ultrasonic waves; two ultrasonic wave receivers (20, 21) that receive reflected waves that reflect off a moving object and bounce back; a mixer (34) that extracts a beat signal from the received reflected waves; a phase difference acquisition unit (37) that determines a phase difference for two series of extracted beat signals; and a position detection unit (38) that detects the position of the moving object on the basis of the obtained phase difference for two series of beat signals. The distance L between the two ultrasonic wave receivers (20, 21) is set on the basis of the following formula (1), where λ is the wavelength of the transmitted ultrasonic waves and θ is the desired detectable angle: Distance L = (λ/2)/sin(θ/2) •••(1).

Description

移動物体検出装置Moving object detection device
　本発明は、超音波を利用して移動物体の位置を検出する移動物体検出装置に関する。 The present invention relates to a moving object detection apparatus that detects the position of a moving object using ultrasonic waves.
　従来から、電波や超音波などの探索波を送信するとともに、物体に反射して戻ってきた反射波を受信し、物体の有無や位置などを検出する装置が知られている。ここで、特許文献１には、送信した電波（又は超音波）の反射波から得られるドップラ信号から、路面に設置された位置マーカと自車との角度を検出する車両位置検出装置が開示されている。 2. Description of the Related Art Conventionally, there are known devices that transmit search waves such as radio waves and ultrasonic waves and receive reflected waves that are reflected back from an object and detect the presence and position of the object. Here, Patent Document 1 discloses a vehicle position detection device that detects an angle between a position marker installed on a road surface and a host vehicle from a Doppler signal obtained from a reflected wave of transmitted radio waves (or ultrasonic waves). ing.
　この車両位置検出装置は、車両に搭載されるドップラ検出用センサを有している。ドップラ検出用センサは、予め路面上設置にされた位置マーカに対して周波数ｆ０の電波を探索波として送信する。ここで、車両が速度Ｖで走行している場合、反射波は、ドップラ効果によって周波数がｆ０からｆｉに偏移する。アンテナで受信された周波数ｆｉの反射波は、送信信号の一部とともにミキサに入力され、混合される。ミキサからの出力のうち、周波数ｆｄ＝ｆ０－ｆｉの成分が可変フィルタで選択され、ドップラ信号として相対速度抽出手段に与えられる。相対速度抽出手段は、次の（１）式から、位置マーカとの相対速度Ｖ’を算出する。
　ｆｄ＝２×ｆ０×Ｖ’／ｃ　・・・（１）
　ここで、ｃは光速（３×１０８（ｍ／ｓｅｃ））
位置検出手段は、車両の走行速度Ｖを車速センサで検出し、走行速度Ｖと相対速度Ｖ’とから、次の（２）式に従って車両の走行方向と位置マーカとの角度θを求める。
　Ｖ’＝Ｖｃｏｓθ　・・・（２） This vehicle position detection device has a Doppler detection sensor mounted on the vehicle. The Doppler detection sensor transmits a radio wave having a frequency f 0 as a search wave to a position marker previously set on the road surface. Here, when the vehicle is traveling at the speed V, the frequency of the reflected wave shifts from f 0 to fi due to the Doppler effect. The reflected wave of frequency fi received by the antenna is input to the mixer together with a part of the transmission signal and mixed. Of the output from the mixer, the component of the frequency fd = f 0 -fi is selected by the variable filter and given to the relative speed extracting means as a Doppler signal. The relative speed extracting means calculates a relative speed V ′ with respect to the position marker from the following equation (1).
fd = 2 × f 0 × V ′ / c (1)
Here, c is the speed of light (3 × 10 8 (m / sec))
The position detecting means detects the traveling speed V of the vehicle with a vehicle speed sensor, and obtains the angle θ between the traveling direction of the vehicle and the position marker according to the following equation (2) from the traveling speed V and the relative speed V ′.
V ′ = V cos θ (2)
特開平１０－１０４３４５号公報Japanese Patent Laid-Open No. 10-104345
　上述した特許文献１記載の車両位置検出装置では、車両の速度Ｖと、ドップラ信号から算出される相対速度Ｖ’とに基づいて、車両と位置マーカとの角度θが求められる。この装置では、車両の速度Ｖが分かっていないと車両と位置マーカとの角度θを検出できない。すなわち、位置マーカとの角度θを検出するには、車両の速度Ｖを検出するための車速センサなどが必要なため、センサ構成が複雑で、装置が大型化するおそれがある。そのため、よりシンプルなセンサ構成で（すなわち自車の速度などの検出を要することなく）、例えば小型の携帯機器などにも適用することができる技術が望まれていた。 In the vehicle position detection device described in Patent Document 1 described above, the angle θ between the vehicle and the position marker is obtained based on the vehicle speed V and the relative speed V ′ calculated from the Doppler signal. In this device, the angle θ between the vehicle and the position marker cannot be detected unless the vehicle speed V is known. That is, in order to detect the angle θ with the position marker, a vehicle speed sensor or the like for detecting the vehicle speed V is required, so that the sensor configuration is complicated and the apparatus may be increased in size. Therefore, there has been a demand for a technique that can be applied to, for example, a small portable device with a simpler sensor configuration (ie, without detecting the speed of the host vehicle).
　本発明は、上記問題点を解消する為になされたものであり、超音波を利用して移動物体の位置を検出する移動物体検出装置において、シンプルなセンサ構成で、より小型化が可能な移動物体検出装置を提供することを目的とする。 The present invention has been made to solve the above-described problems, and in a moving object detection apparatus that detects the position of a moving object using ultrasonic waves, a movement that can be further reduced in size with a simple sensor configuration. An object of the present invention is to provide an object detection device.
　本発明に係る移動物体検出装置は、超音波を送信する超音波送信機と、超音波送信機により送信され、移動物体に反射して戻ってくる反射波を受信する複数の超音波受信機と、複数の超音波受信機それぞれによって受信された反射波からビート信号を抽出するビート抽出手段と、ビート抽出手段により抽出された複数のビート信号の位相差を求める位相差取得手段と、位相差取得手段により求められた複数のビート信号の位相差に基づいて、移動物体の位置を検出する位置検出手段とを備え、上記複数の超音波受信機間の距離が、所望する検出可能角度と送信される超音波の波長とに応じて、複数の超音波受信機それぞれに到達する超音波の位相差が１８０°以下となるように設定されることを特徴とする。 A moving object detection apparatus according to the present invention includes an ultrasonic transmitter that transmits ultrasonic waves, and a plurality of ultrasonic receivers that receive reflected waves that are transmitted from the ultrasonic transmitter and reflected back to the moving object. A beat extracting means for extracting a beat signal from reflected waves received by each of the plurality of ultrasonic receivers, a phase difference obtaining means for obtaining a phase difference between the plurality of beat signals extracted by the beat extracting means, and a phase difference obtaining Position detecting means for detecting the position of the moving object based on the phase difference of the plurality of beat signals obtained by the means, and the distance between the plurality of ultrasonic receivers is transmitted as a desired detectable angle. The phase difference of the ultrasonic waves reaching each of the plurality of ultrasonic receivers is set to be 180 ° or less according to the wavelength of the ultrasonic wave.
　ところで、移動物体に超音波が当たると、ドップラシフトにより超音波の周波数が偏移する。本発明に係る移動物体検出装置によれば、移動物体により反射された反射波（すなわちドップラシフトによって周波数が偏移した反射波）が複数の超音波受信機により受信される。そして、複数の超音波受信機毎にビート信号が抽出され、抽出されたビート信号の位相差に基づいて、移動物体の位置が検出される。ここで、複数の超音波受信機間の距離は、所望する検出可能角度と送信される超音波の波長とに基づいて、複数の超音波受信機それぞれに到達する超音波の位相差が１８０°を越えないように（すなわち半波長以上ずれることがないように）設定されているため、ビート信号の位相差から移動物体の位置を検出することができる。このように、本発明に係る移動物体検出装置によれば、例えば、自機の速度が分からなくても移動物体の位置を検出することができるため、よりシンプルなセンサ構成（すなわち、超音波送信機及び超音波受信機のみ）で移動物体の位置を検出することができ、装置をより小型化することが可能となる。 By the way, when an ultrasonic wave hits a moving object, the frequency of the ultrasonic wave shifts due to Doppler shift. According to the moving object detection device of the present invention, the reflected wave reflected by the moving object (that is, the reflected wave whose frequency is shifted by the Doppler shift) is received by the plurality of ultrasonic receivers. A beat signal is extracted for each of the plurality of ultrasonic receivers, and the position of the moving object is detected based on the phase difference of the extracted beat signals. Here, the distance between the plurality of ultrasonic receivers is such that the phase difference of the ultrasonic waves reaching each of the plurality of ultrasonic receivers is 180 ° based on the desired detectable angle and the wavelength of the transmitted ultrasonic waves. Therefore, the position of the moving object can be detected from the phase difference of the beat signals. As described above, according to the moving object detection device of the present invention, for example, the position of the moving object can be detected without knowing the speed of the own device, and thus a simpler sensor configuration (that is, ultrasonic transmission). The position of the moving object can be detected by only the machine and the ultrasonic receiver), and the apparatus can be further downsized.
　本発明に係る移動物体検出装置では、上記複数の超音波受信機間の距離が、次式（３）に基づいて設定されることが好ましい。
　超音波受信機間の距離Ｌ＝（λ／２）／ｓｉｎ（θ／２）　・・・（３）
　ただし、λは送信される超音波の波長、θは所望する検出可能角度 In the moving object detection device according to the present invention, it is preferable that the distance between the plurality of ultrasonic receivers is set based on the following equation (3).
Distance between ultrasonic receivers L = (λ / 2) / sin (θ / 2) (3)
Where λ is the wavelength of the transmitted ultrasonic wave and θ is the desired detectable angle
　このような間隔で（すなわち上記（３）式に従って）複数の超音波受信機を配置すれば、所望の検出可能角度において、複数の超音波受信機それぞれに到達する超音波の位相差を１８０°以下にすることができる。上記（３）式によれば、例えば、４０ＫＨｚの超音波を用い、所望する検出可能角度が６０°の場合には、超音波受信機間の距離は、λ＝８．５ｍｍ（以下）となる。 If a plurality of ultrasonic receivers are arranged at such an interval (that is, according to the above equation (3)), the phase difference of the ultrasonic waves reaching each of the plurality of ultrasonic receivers at a desired detectable angle is 180 °. It can be: According to the above equation (3), for example, when a 40 KHz ultrasonic wave is used and the desired detectable angle is 60 °, the distance between the ultrasonic receivers is λ = 8.5 mm (below). .
　本発明に係る移動物体検出装置では、上記複数の超音波受信機それぞれが、超音波送信機との間隔が等しくなるように配置されることが好ましい。 In the moving object detection device according to the present invention, it is preferable that each of the plurality of ultrasonic receivers is arranged so that the distance from the ultrasonic transmitter is equal.
　この場合、複数の超音波受信機それぞれと超音波送信機との間隔が等しいため、超音波受信機と超音波送信機との間隔が異なることによって生じるビート信号の位相ずれの補正が不要となる。よって、演算などの処理負荷が軽減されるとともに、より精度良く移動物体の位置を検出することができる。 In this case, since the interval between each of the plurality of ultrasonic receivers and the ultrasonic transmitter is equal, correction of the phase shift of the beat signal caused by the difference in the interval between the ultrasonic receiver and the ultrasonic transmitter becomes unnecessary. . Therefore, the processing load such as calculation is reduced, and the position of the moving object can be detected with higher accuracy.
　本発明に係る移動物体検出装置は、３個の超音波受信機を備え、当該３個の超音波受信機が、互いの間隔がすべて等しくなるように配置されることが好ましい。 It is preferable that the moving object detection apparatus according to the present invention includes three ultrasonic receivers, and the three ultrasonic receivers are arranged so that the intervals between them are all equal.
　この場合、３個の超音波受信機について、相互の間隔がすべて等しいため、各超音波受信機において検出可能角度と受信機間距離との関係が異ならない。よって、同一の位置検出アルゴリズムを適用することができる。よって、演算などの処理負荷が軽減されるとともに、より精度良く移動物体の位置を検出することができる。また、３個の超音波受信機を備えることにより、３次元での移動物体の位置を検出することができる。 In this case, since the intervals between the three ultrasonic receivers are all equal, the relationship between the detectable angle and the distance between the receivers does not differ in each ultrasonic receiver. Therefore, the same position detection algorithm can be applied. Therefore, the processing load such as calculation is reduced, and the position of the moving object can be detected with higher accuracy. Further, by providing three ultrasonic receivers, it is possible to detect the position of a moving object in three dimensions.
　本発明によれば、超音波を利用して移動物体の位置を検出する移動物体検出装置において、シンプルなセンサ構成で、より小型化が可能となる。 According to the present invention, a moving object detection apparatus that detects the position of a moving object using ultrasonic waves can be further downsized with a simple sensor configuration.
第１実施形態に係る移動物体検出装置の構成を示すブロック図である。It is a block diagram which shows the structure of the moving object detection apparatus which concerns on 1st Embodiment. 検出可能角度と超音波受信機間距離との関係を説明するための図である。It is a figure for demonstrating the relationship between a detectable angle and the distance between ultrasonic receivers. 検出可能角度と超音波受信機間距離との関係を示すグラフである。It is a graph which shows the relationship between a detectable angle and the distance between ultrasonic receivers. 第１実施形態に係る移動物体検出装置を構成する超音波送信機と超音波受信機の配置の他の例を示す図である。It is a figure which shows the other example of arrangement | positioning of the ultrasonic transmitter which comprises the moving object detection apparatus which concerns on 1st Embodiment, and an ultrasonic receiver. ２つの超音波受信機それぞれの受信波形（ビート信号）の一例を示す図である。It is a figure which shows an example of each received waveform (beat signal) of two ultrasonic receivers. 第１実施形態に係る移動物体検出装置による移動物体検出処理の処理手順を示すフローチャートである。It is a flowchart which shows the process sequence of the moving object detection process by the moving object detection apparatus which concerns on 1st Embodiment. 第２実施形態に係る移動物体検出装置の構成を示すブロック図である。It is a block diagram which shows the structure of the moving object detection apparatus which concerns on 2nd Embodiment. 第２実施形態に係る移動物体検出装置を構成する超音波送信機と超音波受信機の配置（超音波送信機と各超音波受信機との距離が等しい場合）を示す図である。It is a figure which shows arrangement | positioning (when the distance of an ultrasonic transmitter and each ultrasonic receiver is equal) of the ultrasonic transmitter which comprises the moving object detection apparatus which concerns on 2nd Embodiment, and an ultrasonic receiver. 第２実施形態に係る移動物体検出装置を構成する超音波送信機と超音波受信機の配置の他の例（超音波送信機と各超音波受信機との距離が異なる場合）を示す図である。It is a figure which shows the other example (when the distance of an ultrasonic transmitter and each ultrasonic receiver differs) of the arrangement | positioning of the ultrasonic transmitter which comprises the moving object detection apparatus which concerns on 2nd Embodiment, and an ultrasonic receiver. is there. ３つの超音波受信機それぞれの受信波形（ビート信号）の一例を示す図である。It is a figure which shows an example of the received waveform (beat signal) of each of three ultrasonic receivers.
　以下、図面を参照して本発明の好適な実施形態について詳細に説明する。なお、各図において、同一要素には同一符号を付して重複する説明を省略する。 Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. In addition, in each figure, the same code | symbol is attached | subjected to the same element and the overlapping description is abbreviate | omitted.
　［第１実施形態］
　まず、図１～図３を併せて用いて、第１実施形態に係る移動物体検出装置１の構成について説明する。図１は、移動物体検出装置１の構成を示すブロック図である。図２は、検出可能角度と超音波受信機間距離との関係を説明するための図である。また、図３は、検出可能角度と超音波受信機間距離との関係を示すグラフである。 [First Embodiment]
First, the configuration of the moving object detection device 1 according to the first embodiment will be described with reference to FIGS. FIG. 1 is a block diagram illustrating a configuration of the moving object detection device 1. FIG. 2 is a diagram for explaining the relationship between the detectable angle and the distance between the ultrasonic receivers. FIG. 3 is a graph showing the relationship between the detectable angle and the distance between the ultrasonic receivers.
　移動物体検出装置１は、超音波を送信するとともに、移動物体によって反射された反射波を複数（２つ）の超音波受信機２０，２１で受信し、受信された反射波からドップラシフトによるビート信号（周波数偏移成分）を抽出し、該ビート信号の位相差に基づいて、移動物体の位置（角度）を検出するものである。そのために、移動物体検出装置１は、超音波を連続的に送信する超音波送信機１０と、超音波を受信する２つの超音波受信機２０，２１と、超音波送信機１０を駆動するとともに、超音波受信機２０，２１により受信された受信信号から移動物体の位置を検出する信号処理ユニット３０とを備えている。この信号処理ユニット３０は、送信信号生成部３１、駆動回路３２、フィルタ／増幅部３３、ミキサ３４、Ａ／Ｄ変換器３５、Ａ／Ｄ値取得部３６、位相差取得部３７、及び動体位置検出部３８を有している。以下、各構成要素について詳細に説明する。 The moving object detection device 1 transmits ultrasonic waves, receives reflected waves reflected by the moving object by a plurality (two) of ultrasonic receivers 20 and 21, and beats by Doppler shift from the received reflected waves. A signal (frequency shift component) is extracted, and the position (angle) of the moving object is detected based on the phase difference of the beat signal. For this purpose, the moving object detection apparatus 1 drives the ultrasonic transmitter 10 that continuously transmits ultrasonic waves, the two ultrasonic receivers 20 and 21 that receive ultrasonic waves, and the ultrasonic transmitter 10. And a signal processing unit 30 for detecting the position of the moving object from the received signals received by the ultrasonic receivers 20 and 21. The signal processing unit 30 includes a transmission signal generation unit 31, a drive circuit 32, a filter / amplification unit 33, a mixer 34, an A / D converter 35, an A / D value acquisition unit 36, a phase difference acquisition unit 37, and a moving object position. A detection unit 38 is provided. Hereinafter, each component will be described in detail.
　超音波送信機１０は、配線２５を介して信号処理ユニット３０に接続されている。超音波送信機１０は、信号処理ユニット３０から入力される超音波駆動信号に応じて、圧電素子（ピエゾ素子）を駆動し、例えば４０ｋＨｚの超音波パルス（超音波信号）を連続的に送信する。 The ultrasonic transmitter 10 is connected to the signal processing unit 30 via the wiring 25. The ultrasonic transmitter 10 drives a piezoelectric element (piezo element) in accordance with an ultrasonic drive signal input from the signal processing unit 30, and continuously transmits, for example, an ultrasonic pulse (ultrasonic signal) of 40 kHz. .
　一方、２つの超音波受信機２０，２１は、超音波送信機１０から送信され、移動物体（及び／又は静止物体）に反射されて戻ってくる反射波、及び、超音波送信機１０から直接到達する超音波を受信する。超音波受信機２０，２１それぞれは、配線２６，２６を介して信号処理ユニット３０に接続されており、超音波受信機２０，２１それぞれから出力された受信信号は信号処理ユニット３０に入力される。 On the other hand, the two ultrasonic receivers 20 and 21 are transmitted from the ultrasonic transmitter 10 and reflected from the moving object (and / or a stationary object) and returned directly, and directly from the ultrasonic transmitter 10. Receiving ultrasound to reach. Each of the ultrasonic receivers 20 and 21 is connected to the signal processing unit 30 via the wirings 26 and 26, and the reception signal output from each of the ultrasonic receivers 20 and 21 is input to the signal processing unit 30. .
　ここで、図２に示される２つの超音波受信機２０，２１間の距離Ｌは、要求される検出可能角度（すなわち所望する検出可能角度）と送信される超音波の波長とに応じて、検出可能領域を画定する外縁上の任意の点から送出された超音波が２つの超音波受信機２０，２１それぞれに到達するときの位相差が１８０°以下となるように設定される。換言すると、検出可能領域を画定する外縁上の任意の点と２つの超音波受信機２０，２１それぞれとを結ぶ直線の長さの差が「超音波の波長λ／２」以下となるように設定される。 Here, the distance L between the two ultrasonic receivers 20 and 21 shown in FIG. 2 depends on the required detectable angle (that is, the desired detectable angle) and the wavelength of the transmitted ultrasonic wave. The phase difference when the ultrasonic wave transmitted from an arbitrary point on the outer edge that defines the detectable region reaches each of the two ultrasonic receivers 20 and 21 is set to be 180 ° or less. In other words, the difference in the lengths of the straight lines connecting any point on the outer edge that defines the detectable region and each of the two ultrasonic receivers 20 and 21 is less than or equal to “ultrasonic wavelength λ / 2”. Is set.
　より具体的には、２つの超音波受信機２０，２１間の距離Ｌは、次式（４）に基づいて設定される。
　距離Ｌ＝（λ／２）／ｓｉｎ（θ／２）　・・・（４）
　ただし、λは送信される超音波の波長、θは所望する検出可能角度 More specifically, the distance L between the two ultrasonic receivers 20 and 21 is set based on the following equation (4).
Distance L = (λ / 2) / sin (θ / 2) (4)
Where λ is the wavelength of the transmitted ultrasonic wave and θ is the desired detectable angle
　よって、所望する検出可能角度が１８０°の場合には、超音波受信機２０，２１間の距離Ｌはλ／２となる。そのため、例えば、４０ｋＨｚの超音波を使用する場合には、超音波受信機２０，２１間の距離Ｌは、４．２５ｍｍ以下に設定される。同様にして、検出可能角度が１２０°の場合には、距離Ｌはλ／√３（４．９ｍｍ）、検出可能角度が９０°の場合には、距離Ｌはλ／√２（６．０ｍｍ）、検出可能角度が６０°の場合には、距離Ｌはλ（８．５ｍｍ）となり、検出可能角度が３０°の場合には、距離Ｌは２λ（１７．０ｍｍ）となる。 Therefore, when the desired detectable angle is 180 °, the distance L between the ultrasonic receivers 20 and 21 is λ / 2. Therefore, for example, when using a 40 kHz ultrasonic wave, the distance L between the ultrasonic receivers 20 and 21 is set to 4.25 mm or less. Similarly, when the detectable angle is 120 °, the distance L is λ / √3 (4.9 mm), and when the detectable angle is 90 °, the distance L is λ / √2 (6.0 mm). ), When the detectable angle is 60 °, the distance L is λ (8.5 mm), and when the detectable angle is 30 °, the distance L is 2λ (17.0 mm).
　ここで、上述した検出可能角度と超音波受信機間距離との関係を図３に示す。図３に示されるように、所望する検出可能角度が大きくなるほど、超音波受信機２０，２１間の距離Ｌは短くなる。このように、２つの超音波受信機２０，２１は、図３のグラフで示される、所望する検出可能角度に応じて定まる距離以内に並べて設置される。 Here, FIG. 3 shows the relationship between the detectable angle and the distance between the ultrasonic receivers. As shown in FIG. 3, as the desired detectable angle increases, the distance L between the ultrasonic receivers 20 and 21 decreases. In this way, the two ultrasonic receivers 20 and 21 are installed side by side within a distance determined according to a desired detectable angle shown in the graph of FIG.
　超音波送信機１０は、図２に示されるように、２つの超音波受信機２０，２１を結ぶ直線の中央に配置される。なお、超音波送信機１０の配置は、この例に限られることなく、任意の位置に配置することができる。すなわち、例えば、図４に示されるように、超音波送信機１０及び２つの超音波受信機２０，２１が、正三角形の各頂点に位置するように配置してもよい。ただし、超音波送信機１０は、２つの超音波受信機２０，２１それぞれとの間隔が等しくなるように配置されることが好ましい。 The ultrasonic transmitter 10 is disposed at the center of a straight line connecting the two ultrasonic receivers 20 and 21 as shown in FIG. In addition, arrangement | positioning of the ultrasonic transmitter 10 is not restricted to this example, It can arrange | position in arbitrary positions. That is, for example, as illustrated in FIG. 4, the ultrasonic transmitter 10 and the two ultrasonic receivers 20 and 21 may be arranged so as to be located at each vertex of an equilateral triangle. However, the ultrasonic transmitter 10 is preferably arranged so that the distance between the two ultrasonic receivers 20 and 21 is equal.
　信号処理ユニット３０は、超音波送信機１０に超音波駆動信号を供給して超音波送信機１０を駆動するとともに、超音波受信機２０，２１により受信された反射波（受信信号）を処理して移動物体の位置を検出する。信号処理ユニット３０は、出力インターフェースとしての駆動回路３２、入力インターフェースとしてのフィルタ／増幅部３３、ミキサ３４、並びにＡ／Ｄ変換器３５、及び、該フィルタ／増幅部３３、ミキサ３４、Ａ／Ｄ変換器３５を介して入力される受信信号に対して信号処理等を行うＣＰＵ、該ＣＰＵに各処理を実行させるためのプログラムやデータ等を記憶するＲＯＭ、演算結果などの各種データを一時的に記憶するＲＡＭ等により構成されている。信号処理ユニット３０では、ＲＯＭに記憶されているプログラムが、ＣＰＵによって実行されることにより、送信信号生成部３１、Ａ／Ｄ値取得部３６、位相差取得部３７、及び動体位置検出部３８の各機能が実現される。なお、ＣＰＵに代えて、例えばＡＳＩＣや、ＦＰＧＡ、ＤＳＰなどを用いてもよい。 The signal processing unit 30 supplies an ultrasonic drive signal to the ultrasonic transmitter 10 to drive the ultrasonic transmitter 10 and processes reflected waves (received signals) received by the ultrasonic receivers 20 and 21. To detect the position of the moving object. The signal processing unit 30 includes a drive circuit 32 as an output interface, a filter / amplifier 33 as an input interface, a mixer 34, and an A / D converter 35, and the filter / amplifier 33, mixer 34, A / D. A CPU that performs signal processing and the like on a received signal input via the converter 35, a ROM that stores programs and data for causing the CPU to execute each process, and various data such as calculation results are temporarily stored. It is composed of a RAM for storing. In the signal processing unit 30, a program stored in the ROM is executed by the CPU, so that the transmission signal generation unit 31, the A / D value acquisition unit 36, the phase difference acquisition unit 37, and the moving object position detection unit 38 Each function is realized. In place of the CPU, for example, an ASIC, FPGA, DSP, or the like may be used.
　送信信号生成部３１は、超音波周波数（本実施形態では４０ｋＨｚ）の超音波駆動信号を生成し、駆動回路３２へ出力する。駆動回路３２は、送信信号生成部３１から入力された超音波駆動信号を増幅し、配線２５を通して超音波送信機１０に供給する。上述したように、超音波送信機１０は、この超音波駆動信号によって駆動され、超音波を送信する。 The transmission signal generation unit 31 generates an ultrasonic drive signal having an ultrasonic frequency (40 kHz in the present embodiment) and outputs the ultrasonic drive signal to the drive circuit 32. The drive circuit 32 amplifies the ultrasonic drive signal input from the transmission signal generation unit 31 and supplies the amplified ultrasonic drive signal to the ultrasonic transmitter 10 through the wiring 25. As described above, the ultrasonic transmitter 10 is driven by the ultrasonic drive signal and transmits ultrasonic waves.
　フィルタ／増幅部３３は、例えばオペアンプ等を用いた増幅回路、及び、ローパスフィルタ又はバンドパスフィルタ等によって構成されており、超音波受信機２０，２１それぞれにより受信され、配線２６を通して入力された受信信号を増幅した後、所望の信号以外の信号（ノイズ）を除去する。フィルタ／増幅部３３で増幅され、ノイズが除去された受信信号は、ミキサ３４に出力される。 The filter / amplifier 33 is configured by an amplifier circuit using, for example, an operational amplifier, a low-pass filter, a band-pass filter, or the like, and is received by the ultrasonic receivers 20 and 21 and received via the wiring 26. After amplifying the signal, a signal (noise) other than the desired signal is removed. The received signal that has been amplified by the filter / amplifier 33 and from which noise has been removed is output to the mixer 34.
　ミキサ３４は、２つの超音波受信機２０，２１それぞれによって受信された受信信号（反射波）と、送信信号生成部３１から入力される超音波駆動信号（送信波）とをミキシング（混合）してビート信号を抽出するものである。すなわち、ミキサ３４は、請求の範囲に記載のビート抽出手段として機能する。ここで、超音波受信機２０，２１で受信される受信波には、超音波送信機１０から直接届く直接波と移動物体に反射された反射波とを含んでいるが、このうち、反射波はドップラシフトによって周波数が偏移している。超音波駆動信号（送信波）と受信波（反射波）とがミキサ３４で混合されることで、図５に一点鎖線で示されるビート信号（ドップラ周波数成分）が抽出される。なお、ミキサ３４により抽出されたビート信号はＡ／Ｄ変換器３５に出力される。 The mixer 34 mixes (mixes) the reception signals (reflected waves) received by the two ultrasonic receivers 20 and 21 and the ultrasonic drive signals (transmission waves) input from the transmission signal generation unit 31. To extract the beat signal. That is, the mixer 34 functions as a beat extraction unit described in the claims. Here, the received waves received by the ultrasonic receivers 20 and 21 include a direct wave directly reaching from the ultrasonic transmitter 10 and a reflected wave reflected by the moving object. The frequency is shifted by Doppler shift. By mixing the ultrasonic drive signal (transmitted wave) and the received wave (reflected wave) by the mixer 34, a beat signal (Doppler frequency component) indicated by a one-dot chain line in FIG. 5 is extracted. The beat signal extracted by the mixer 34 is output to the A / D converter 35.
　Ａ／Ｄ変換器３５は、アナログ信号をディジタルデータに変換するアナログ－ディジタル変換器であり、ミキサ３４から入力されるビート信号（アナログ信号）をディジタルデータに変換する。Ａ／Ｄ値取得部３６は、Ａ／Ｄ変換器３５の動作を制御し、Ａ／Ｄ変換器３５によりディジタルデータ化されたビート信号を取得する。なお、Ａ／Ｄ値取得部３６で取得されたディジタルデータは、位相差取得部３７に出力される。 The A / D converter 35 is an analog-digital converter that converts an analog signal into digital data, and converts a beat signal (analog signal) input from the mixer 34 into digital data. The A / D value acquisition unit 36 controls the operation of the A / D converter 35 and acquires the beat signal converted into digital data by the A / D converter 35. The digital data acquired by the A / D value acquisition unit 36 is output to the phase difference acquisition unit 37.
　位相差取得部３７は、ミキサ３４により抽出され、Ａ／Ｄ値取得部３６を介して読み込まれた２系統のビート信号の位相を比較して位相差（図５参照）を求める。すなわち、位相差取得部３７は、請求の範囲に記載の位相差取得手段として機能する。取得されたビート信号の位相差は、動体位置検出部３８に出力される。 The phase difference acquisition unit 37 compares the phases of two beat signals extracted by the mixer 34 and read via the A / D value acquisition unit 36 to obtain a phase difference (see FIG. 5). That is, the phase difference acquisition unit 37 functions as a phase difference acquisition unit described in the claims. The acquired phase difference of the beat signal is output to the moving object position detector 38.
　動体位置検出部３８は、位相差取得部３７により取得された２系統のビート信号の位相差に基づいて、移動物体の２次元位置（移動物体との相対的な角度）を検出する。すなわち、動体位置検出部３８は、請求の範囲に記載の位置検出手段として機能する。例えば、図５に示された例では、図２において図面左側に位置する超音波受信機２０の受信信号から抽出されたビート信号の位相が、図面右側に位置する超音波受信機２１の受信信号から抽出されたビート信号の位相よりも遅れている。そのため、この場合には、図２において図面左側に移動物体が存在することが検出される。なお、位相差の大きさに応じて、移動物体との角度が検出される。なお、動体位置検出部３８により検出された移動物体の位置（移動物体との角度）は、外部機器に出力される。 The moving object position detection unit 38 detects the two-dimensional position (relative angle with the moving object) of the moving object based on the phase difference between the two systems of beat signals acquired by the phase difference acquisition unit 37. That is, the moving body position detection unit 38 functions as a position detection unit described in the claims. For example, in the example shown in FIG. 5, the phase of the beat signal extracted from the received signal of the ultrasonic receiver 20 located on the left side of the drawing in FIG. 2 is the received signal of the ultrasonic receiver 21 located on the right side of the drawing. The phase of the beat signal extracted from is delayed. Therefore, in this case, it is detected that a moving object exists on the left side of FIG. The angle with the moving object is detected according to the magnitude of the phase difference. Note that the position of the moving object (angle with the moving object) detected by the moving object position detection unit 38 is output to an external device.
　次に、図６を参照しつつ、移動物体検出装置１の動作について説明する。図６は、移動物体検出装置１による移動物体検出処理の処理手順を示すフローチャートである。 Next, the operation of the moving object detection device 1 will be described with reference to FIG. FIG. 6 is a flowchart illustrating a processing procedure of the moving object detection process performed by the moving object detection device 1.
　まず、送信信号生成部３１において、連続的な超音波駆動信号が生成され、出力される。出力された超音波駆動信号は、駆動回路３２で増幅されて超音波送信機１０に供給される。超音波送信機１０は、供給された超音波駆動信号によって駆動され、超音波信号を連続的に送信する（ステップＳ１００）。 First, in the transmission signal generation unit 31, a continuous ultrasonic drive signal is generated and output. The output ultrasonic drive signal is amplified by the drive circuit 32 and supplied to the ultrasonic transmitter 10. The ultrasonic transmitter 10 is driven by the supplied ultrasonic drive signal and continuously transmits the ultrasonic signal (step S100).
　ステップＳ１００において超音波送信機１０から送信された超音波信号は、空間を伝搬し、移動物体（及び／又は静止物体）で反射される。反射された超音波信号は、空間を戻り、超音波受信機２０，２１によって受信される（ステップＳ１０２）。 The ultrasonic signal transmitted from the ultrasonic transmitter 10 in step S100 propagates through space and is reflected by a moving object (and / or a stationary object). The reflected ultrasonic signal returns to the space and is received by the ultrasonic receivers 20 and 21 (step S102).
　ステップＳ１０２において超音波受信機２０，２１それぞれによって受信された反射波は、フィルタ／増幅部３３で増幅されてノイズが除去された後、ミキサ３４において、送信信号生成部３１から入力される超音波駆動信号（送信波）とミキシングされてビート信号が抽出される（ステップＳ１０４）。 The reflected waves received by the ultrasonic receivers 20 and 21 in step S102 are amplified by the filter / amplifier 33 and noise is removed, and then the ultrasonic waves input from the transmission signal generator 31 in the mixer 34 are obtained. The beat signal is extracted by mixing with the drive signal (transmission wave) (step S104).
　ステップＳ１０４において抽出されたビート信号は、Ａ／Ｄ変換器３５によりディジタルデータに変換され、Ａ／Ｄ値取得部３６を介して位相差取得部３７に読み込まれる。そして、位相差取得部３７により２系統のビート信号の位相が比較されて位相差（図５参照）が求められる（ステップＳ１０６）。 The beat signal extracted in step S104 is converted into digital data by the A / D converter 35 and read into the phase difference acquisition unit 37 via the A / D value acquisition unit 36. Then, the phase difference acquisition unit 37 compares the phases of the two beat signals to obtain the phase difference (see FIG. 5) (step S106).
　続くステップＳ１０８では、ステップＳ１０６において求められた２系統のビート信号の位相差に基づいて、移動物体の２次元位置（移動物体との角度）が検出される。移動物体の２次元位置の検出の仕方については、上述した通りであるので、ここでは詳細な説明を省略する。なお、ステップＳ１０８において検出された移動物体の位置は、外部機器に出力される。 In the subsequent step S108, the two-dimensional position (angle with respect to the moving object) of the moving object is detected based on the phase difference between the two beat signals obtained in step S106. Since the method of detecting the two-dimensional position of the moving object is as described above, detailed description thereof is omitted here. Note that the position of the moving object detected in step S108 is output to an external device.
　本実施形態によれば、超音波送信機１０から直接到達した超音波と、移動物体により反射された反射波（すなわちドップラシフトによって周波数が偏移した反射波）とが重なり合った状態で２つの超音波受信機２０，２１により受信される。そして、２つの超音波受信機２０，２１毎にビート信号が抽出され、抽出されたビート信号の位相差に基づいて、移動物体の位置（移動物体との角度）が検出される。ここで、２つの超音波受信機２０，２１間の距離は、所望する検出可能角度と送信される超音波の波長とに基づいて、２つの超音波受信機２０，２１それぞれに到達する超音波の位相差が１８０°を越えないように（すなわち半波長以上ずれることがないように）設定されている。そのため、ビート信号の位相差から移動物体の位置を検出することができる。このように、本実施形態によれば、例えば、自機の速度が分からなくても移動物体の位置を検出することができるため、よりシンプルなセンサ構成（すなわち、超音波送信機１０及び超音波受信機２０，２１のみ）で移動物体の位置を検出することができ、装置をより小型化することが可能となる。また、本実施形態によれば、静止物体は検知することなく、移動物体のみを検出することができる。 According to the present embodiment, two ultrasonic waves are overlapped with an ultrasonic wave directly reaching from the ultrasonic transmitter 10 and a reflected wave reflected by a moving object (that is, a reflected wave whose frequency is shifted by Doppler shift). It is received by the sound wave receivers 20 and 21. A beat signal is extracted for each of the two ultrasonic receivers 20 and 21, and the position of the moving object (angle with respect to the moving object) is detected based on the phase difference between the extracted beat signals. Here, the distance between the two ultrasonic receivers 20 and 21 is an ultrasonic wave reaching each of the two ultrasonic receivers 20 and 21 based on the desired detectable angle and the wavelength of the transmitted ultrasonic waves. Is set so that the phase difference does not exceed 180 ° (that is, it is not shifted more than half a wavelength). Therefore, the position of the moving object can be detected from the phase difference of the beat signal. As described above, according to the present embodiment, for example, the position of a moving object can be detected without knowing the speed of the own device, and thus a simpler sensor configuration (that is, the ultrasonic transmitter 10 and the ultrasonic wave). The position of the moving object can be detected by only the receivers 20 and 21), and the apparatus can be further downsized. Further, according to the present embodiment, it is possible to detect only a moving object without detecting a stationary object.
　特に、本実施形態によれば、上記（４）式に従って、２つの超音波受信機２０，２１が配置されているため、所望の検出可能角度において、２つの超音波受信機２０，２１それぞれに到達する超音波の位相差を１８０°以下にすることができる。その際に、超音波送信機１０及び２つの超音波受信機２０，２１それぞれは、近距離（例えば、４０ＫＨｚの超音波を用い、所望する検出可能角度が６０°の場合には、８．５ｍｍ以下）に配置されることとなるため、装置を小型化することができる。 In particular, according to the present embodiment, since the two ultrasonic receivers 20 and 21 are arranged according to the above equation (4), each of the two ultrasonic receivers 20 and 21 is arranged at a desired detectable angle. The phase difference of the reaching ultrasonic waves can be 180 ° or less. At that time, each of the ultrasonic transmitter 10 and the two ultrasonic receivers 20 and 21 uses a short distance (for example, 40 KHz ultrasonic waves and 8.5 mm when the desired detectable angle is 60 °). The apparatus can be reduced in size.
　また、本実施形態によれば、２つの超音波受信機２０，２１それぞれと超音波送信機１０との間隔が等しいため、超音波受信機２０，２１と超音波送信機１０との間隔が異なることによって生じるビート信号の位相ずれの補正が不要となる。よって、演算などの処理負荷を軽減できるとともに、より精度良く移動物体の位置を検出することが可能となる。 Further, according to the present embodiment, since the distance between the two ultrasonic receivers 20 and 21 and the ultrasonic transmitter 10 is equal, the distance between the ultrasonic receivers 20 and 21 and the ultrasonic transmitter 10 is different. Correction of the phase shift of the beat signal caused by this is not necessary. Therefore, it is possible to reduce the processing load such as calculation and to detect the position of the moving object with higher accuracy.
　［第２実施形態］
　上述した、第１実施形態に係る移動物体検出装置１は、２つの超音波受信機２０，２１を有し、２系統のビート信号の位相差に基づいて、移動物体の２次元位置を検出した。これに対して、３つの超音波受信機２０，２１，２２を有し、３系統のビート信号それぞれの位相差から、移動物体の３次元位置を検出する構成とすることもできる。次に、図７を参照しつつ、第２実施形態に係る移動物体検出装置２の構成について説明する。図７は、移動物体検出装置２の構成を示すブロック図である。なお、図７において第１実施形態と同一又は同等の構成要素については同一の符号が付されている。 [Second Embodiment]
The moving object detection apparatus 1 according to the first embodiment described above includes two ultrasonic receivers 20 and 21 and detects the two-dimensional position of the moving object based on the phase difference between the two systems of beat signals. . On the other hand, it can also be set as the structure which has the three ultrasonic receivers 20, 21, and 22 and detects the three-dimensional position of a moving object from the phase difference of each of 3 types of beat signals. Next, the configuration of the moving object detection device 2 according to the second embodiment will be described with reference to FIG. FIG. 7 is a block diagram illustrating a configuration of the moving object detection device 2. In FIG. 7, the same or equivalent components as those in the first embodiment are denoted by the same reference numerals.
　移動物体検出装置２は、上述した移動物体検出装置１の構成に加えて、超音波受信機２２、及び、該超音波受信機２２により受信された受信信号の処理を行うフィルタ／増幅部３３、ミキサ３４、Ａ／Ｄ変換器３５をさらに有している点で移動物体検出装置１と異なっている。また、位相差取得部３７Ａは、３系統のビート信号の位相を比較して位相差を取得する点で、上述した位相差取得部３７と異なっている。さらに、動体位置検出部３８Ａは、３系統のビート信号の位相差に基づいて、移動物体の３次元位置を検出する点で、上述した動体位置検出部３８と異なっている。以下、これらの異なる点を中心に説明する。その他の構成は、上述した移動物体検出装置１と同一または同様であるので、ここでは詳細な説明を省略する。 In addition to the configuration of the moving object detection device 1 described above, the moving object detection device 2 includes an ultrasonic receiver 22 and a filter / amplifier 33 that performs processing of a received signal received by the ultrasonic receiver 22. The moving object detection apparatus 1 is different in that it further includes a mixer 34 and an A / D converter 35. The phase difference acquisition unit 37A is different from the phase difference acquisition unit 37 described above in that the phase difference is acquired by comparing the phases of the three beat signals. Furthermore, the moving object position detection unit 38A is different from the moving object position detection unit 38 described above in that it detects the three-dimensional position of the moving object based on the phase difference between the three beat signals. Hereinafter, these different points will be mainly described. Other configurations are the same as or similar to those of the moving object detection device 1 described above, and thus detailed description thereof is omitted here.
　超音波受信機２２は、上述した超音波受信機２０，２１と同様に、超音波送信機１０か送信され、移動物体（及び／又は静止物体）に反射されて戻ってくる反射波、及び、超音波送信機１０から直接到達する超音波を受信する。超音波受信機２２は、配線２６を介して信号処理ユニット３０Ａに接続されており、超音波受信機２２から出力された受信信号は信号処理ユニット３０Ａに入力される。ここで、３つの超音波受信機２０，２１，２２は、図８に示されるように、互いの間隔がすべて等しくなるように配置される。なお、図８は、移動物体検出装置２を構成する超音波送信機１０と３つの超音波受信機２０，２１，２２の配置（超音波送信機１０と各超音波受信機２０，２１，２２との距離が等しい場合）を示す図である。 Similarly to the ultrasonic receivers 20 and 21 described above, the ultrasonic receiver 22 is transmitted from the ultrasonic transmitter 10 and is reflected by a moving object (and / or a stationary object) and returns to the reflected wave, and The ultrasonic waves that reach directly from the ultrasonic transmitter 10 are received. The ultrasonic receiver 22 is connected to the signal processing unit 30A via the wiring 26, and the reception signal output from the ultrasonic receiver 22 is input to the signal processing unit 30A. Here, as shown in FIG. 8, the three ultrasonic receivers 20, 21, and 22 are arranged so that their intervals are all equal. 8 shows the arrangement of the ultrasonic transmitter 10 and the three ultrasonic receivers 20, 21, 22 constituting the moving object detection apparatus 2 (the ultrasonic transmitter 10 and the ultrasonic receivers 20, 21, 22). FIG.
　ここで、図８に示される３つの超音波受信機２０，２１，２２それぞれは、互いに隣り合う超音波受信機との距離が、上述した式（４）に基づいて設定される。すなわち、３つの超音波受信機２０，２１，２２は、互いの距離が、上述した図３のグラフで示される、所望する検出可能角度に応じて定まる距離以内になるように設置される。 Here, in each of the three ultrasonic receivers 20, 21, and 22 shown in FIG. 8, the distance from the adjacent ultrasonic receiver is set based on the above-described equation (4). That is, the three ultrasonic receivers 20, 21, and 22 are installed such that the distance between them is within a distance determined according to the desired detectable angle shown in the graph of FIG.
　また、図８に示されるように、超音波送信機１０は、３つの超音波受信機２０，２１，２２それぞれとの間隔が等しくなるように配置されることが好ましい。ただし、超音波送信機１０の配置は、この例に限られることなく、任意の位置に配置することができる。すなわち、例えば図９に示されるように、超音波送信機１０及び３つの超音波受信機２０，２１，２２が、正方形の各頂点に位置するように配置してもよい。ここで、図９は、移動物体検出装置２を構成する超音波送信機１０と３つの超音波受信機２０，２１，２２の配置の他の例（超音波送信機１０と各超音波受信機２０，２１，２２との距離が異なる場合）を示す図である。図９に示されるように配置すれば、超音波送信機１０及び超音波受信機２０，２１，２２の取付け面積をより小さくすることができる。 Further, as shown in FIG. 8, the ultrasonic transmitter 10 is preferably arranged so that the intervals between the three ultrasonic receivers 20, 21, and 22 are equal. However, the arrangement of the ultrasonic transmitter 10 is not limited to this example, and can be arranged at an arbitrary position. That is, for example, as shown in FIG. 9, the ultrasonic transmitter 10 and the three ultrasonic receivers 20, 21, and 22 may be arranged so as to be located at each vertex of a square. Here, FIG. 9 shows another example of the arrangement of the ultrasonic transmitter 10 and the three ultrasonic receivers 20, 21, 22 constituting the moving object detection apparatus 2 (the ultrasonic transmitter 10 and each ultrasonic receiver). 20, 21, and 22 are different from each other). If it arrange | positions as FIG. 9 shows, the attachment area of the ultrasonic transmitter 10 and the ultrasonic receiver 20,21,22 can be made smaller.
　位相差取得部３７Ａは、ミキサ３４により抽出され、Ａ／Ｄ値取得部３６を介して読み込まれた３系統のビート信号の位相を比較して位相差（図１０参照）を求める。すなわち、位相差取得部３７Ａも、請求の範囲に記載の位相差取得手段として機能する。取得されたビート信号の位相差は、動体位置検出部３８Ａに出力される。 The phase difference acquisition unit 37A compares the phases of the three beat signals extracted by the mixer 34 and read through the A / D value acquisition unit 36 to obtain a phase difference (see FIG. 10). That is, the phase difference acquisition unit 37A also functions as a phase difference acquisition unit described in the claims. The phase difference of the acquired beat signal is output to the moving object position detection unit 38A.
　動体位置検出部３８Ａは、位相差取得部３７Ａにより求められた３系統のビート信号の位相差に基づいて、移動物体の３次元位置（移動物体との相対的な角度）を検出する。すなわち、動体位置検出部３８Ａも、請求の範囲に記載の位置検出手段として機能する。 The moving object position detection unit 38A detects the three-dimensional position of the moving object (relative angle with the moving object) based on the phase difference of the three systems of beat signals obtained by the phase difference acquisition unit 37A. That is, the moving body position detection unit 38A also functions as the position detection unit described in the claims.
　例えば、図１０に示された例では、図８において図面左下側に位置する超音波受信機２０の受信信号から抽出されたビート信号の位相が、図面上側に位置する超音波受信機２２の受信信号から抽出されたビート信号の位相よりも遅れている。かつ、図８において図面右下側に位置する超音波受信機２１の受信信号から抽出されたビート信号の位相が、図面左下側に位置する超音波受信機２０の受信信号から抽出されたビート信号の位相、及び、図面上側に位置する超音波受信機２２の受信信号から抽出されたビート信号の位相よりも遅れている。そのため、この場合には、超音波送信機１０及び超音波受信機２０，２１，２２の取付面から見て左上方に移動物体が存在することが検出される。なお、位相差の大きさに応じて、移動物体との角度が検出される。なお、動体位置検出部３８Ａにより検出された移動物体の位置（移動物体との角度）は、外部機器に出力される。 For example, in the example shown in FIG. 10, the phase of the beat signal extracted from the reception signal of the ultrasonic receiver 20 located on the lower left side in FIG. 8 is the reception of the ultrasonic receiver 22 located on the upper side of the figure. It is behind the phase of the beat signal extracted from the signal. And the beat signal extracted from the received signal of the ultrasonic receiver 20 located on the lower left side of the drawing is the phase of the beat signal extracted from the received signal of the ultrasonic receiver 21 located on the lower right side of the drawing in FIG. And the phase of the beat signal extracted from the reception signal of the ultrasonic receiver 22 located on the upper side of the drawing. Therefore, in this case, it is detected that there is a moving object in the upper left as viewed from the mounting surfaces of the ultrasonic transmitter 10 and the ultrasonic receivers 20, 21, and 22. The angle with the moving object is detected according to the magnitude of the phase difference. Note that the position of the moving object (angle with the moving object) detected by the moving object position detection unit 38A is output to an external device.
　本実施形態によれば、３個の超音波受信機２０，２１，２２を有することにより、３次元での移動物体の位置を検出することができる。また、本実施形態によれば、３個の超音波受信機２０，２１，２２について、相互の間隔がすべて等しいため、各超音波受信機２０，２１，２２において検出可能角度と受信機間距離との関係が変わらない。よって、同一の位置検出アルゴリズムを適用することができる。よって、演算などの処理負荷を軽減できるとともに、より精度良く移動物体の位置を検出することが可能となる。 According to the present embodiment, the three ultrasonic receivers 20, 21, 22 can be used to detect the position of the moving object in three dimensions. Further, according to the present embodiment, the three ultrasonic receivers 20, 21, and 22 are all equal in interval, so that the detectable angle and the inter-receiver distance in each of the ultrasonic receivers 20, 21, and 22. The relationship with is unchanged. Therefore, the same position detection algorithm can be applied. Therefore, it is possible to reduce the processing load such as calculation and to detect the position of the moving object with higher accuracy.
　以上、本発明の実施の形態について説明したが、本発明は、上記実施形態に限定されるものではなく種々の変形が可能である。例えば、超音波送信機１０及び超音波受信機２０，２１，２２の配置や使用する超音波の周波数などは上記実施形態に限られることなく、例えば、移動物体検出装置１，２に対する要求仕様などによって任意に設定され得る。その際に、上記実施形態では、超音波送信機１０及び超音波受信機２０，２１，２２を同一平面上に配置したが、これらを立体的に配置してもよい。 Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications can be made. For example, the arrangement of the ultrasonic transmitter 10 and the ultrasonic receivers 20, 21, and 22 and the frequency of the ultrasonic waves to be used are not limited to the above-described embodiment, and for example, required specifications for the moving object detection devices 1 and 2 Can be set arbitrarily. In that case, in the said embodiment, although the ultrasonic transmitter 10 and the ultrasonic receivers 20, 21, and 22 were arrange | positioned on the same plane, you may arrange | position these three-dimensionally.
　また、移動物体検出装置１，２は、さまざまな機器に取り付けて利用することができる。例えば、移動物体検出装置１，２を自動車のバンパーに取り付けて、歩行者の有無・位置を検出し、検出結果に応じて、スピーカから警告音を発するようにしてもよい。このようにすれば、歩行者との接触事故を低減することができる。特に、走行音が静かなＥＶ（電気自動車や電動バイク）において高い効果が期待できる。 Also, the moving object detection devices 1 and 2 can be used by being attached to various devices. For example, the moving object detection devices 1 and 2 may be attached to a bumper of an automobile to detect the presence / absence / position of a pedestrian and emit a warning sound from a speaker according to the detection result. If it does in this way, a contact accident with a pedestrian can be reduced. In particular, a high effect can be expected in EVs (electric cars and electric motorcycles) where the running sound is quiet.
　また、例えば、移動物体検出装置１，２をテレビやパソコンのモニタに取り付け、人の有無・位置を検出し、人の有無に応じて、テレビやモニタの電源をＯＮ／ＯＦＦしたり、人の位置に応じて、サラウンドや音量を調整するようにしてもよい。なお、その際に、移動物体検出装置１，２によれば、動く人のみを検知することができるため、例えば、周辺に配置されているテーブルや椅子などの静止物体による誤検知を生じることはない。 In addition, for example, the moving object detection devices 1 and 2 are attached to a TV or personal computer monitor, and the presence / absence / position of a person is detected, and the TV / monitor is turned on / off according to the presence / absence of a person. Depending on the position, surround and volume may be adjusted. At that time, since the moving object detection devices 1 and 2 can detect only a moving person, for example, erroneous detection due to a stationary object such as a table or a chair arranged in the vicinity may occur. Absent.
　１，２　移動物体検出装置
　１０　超音波送信機
　２０，２１，２２　超音波受信機
　３０，３０Ａ　信号処理ユニット
　３１　送信信号生成部
　３２　駆動回路
　３３　フィルタ／増幅部
　３４　ミキサ
　３５　Ａ／Ｄ変換器
　３６　Ａ／Ｄ値取得部
　３７，３７Ａ　位相差取得部
　３８，３８Ａ　動体位置検出部
  DESCRIPTION OF SYMBOLS 1, 2 Moving object detection apparatus 10 Ultrasonic transmitter 20, 21, 22 Ultrasonic receiver 30, 30A Signal processing unit 31 Transmission signal generation part 32 Drive circuit 33 Filter / amplification part 34 Mixer 35 A / D converter 36 A / D value acquisition unit 37, 37A Phase difference acquisition unit 38, 38A Moving object position detection unit

Claims (4)

  1. 　超音波を送信する超音波送信機と、
    　前記超音波送信機により送信され、移動物体に反射して戻ってくる反射波を受信する複数の超音波受信機と、
    　前記複数の超音波受信機それぞれによって受信された前記反射波からビート信号を抽出するビート抽出手段と、
    　前記ビート抽出手段により抽出された複数のビート信号の位相差を求める位相差取得手段と、
    　前記位相差取得手段により求められた前記複数のビート信号の位相差に基づいて、前記移動物体の位置を検出する位置検出手段と、
    　を備え、
    　前記複数の超音波受信機間の距離は、所望する検出可能角度と送信される超音波の波長とに応じて、前記複数の超音波受信機それぞれに到達する超音波の位相差が１８０°以下となるように設定されることを特徴とする移動物体検出装置。     An ultrasonic transmitter for transmitting ultrasonic waves;
    A plurality of ultrasonic receivers for receiving reflected waves transmitted by the ultrasonic transmitter and reflected back to a moving object;
    Beat extracting means for extracting a beat signal from the reflected wave received by each of the plurality of ultrasonic receivers;
    Phase difference obtaining means for obtaining a phase difference between a plurality of beat signals extracted by the beat extracting means;
    Position detection means for detecting the position of the moving object based on the phase difference of the plurality of beat signals obtained by the phase difference acquisition means;
    With
    The distance between the plurality of ultrasonic receivers is such that the phase difference of the ultrasonic waves reaching each of the plurality of ultrasonic receivers is 180 ° or less depending on the desired detectable angle and the wavelength of the transmitted ultrasonic waves. A moving object detection device characterized by being set to be
  2. 　前記複数の超音波受信機間の距離は、次式（１）に基づいて設定されることを特徴とする請求項１に記載の移動物体検出装置。
    　　超音波受信機間の距離Ｌ＝（λ／２）／ｓｉｎ（θ／２）　・・・（１）
    　　ただし、λは送信される超音波の波長、θは所望する検出可能角度     The moving object detection apparatus according to claim 1, wherein a distance between the plurality of ultrasonic receivers is set based on the following equation (1).
    Distance between ultrasonic receivers L = (λ / 2) / sin (θ / 2) (1)
    Where λ is the wavelength of the transmitted ultrasonic wave and θ is the desired detectable angle
  3. 　前記複数の超音波受信機それぞれは、前記超音波送信機との間隔が等しくなるように配置されることを特徴とする請求項１又は２に記載の移動物体検出装置。 The moving object detection device according to claim 1 or 2, wherein each of the plurality of ultrasonic receivers is arranged so that an interval between the plurality of ultrasonic receivers is equal to the ultrasonic transmitter.
  4. 　３個の超音波受信機を備え、
    　前記３個の超音波受信機は、互いの間隔がすべて等しくなるように配置されることを特徴とする請求項３に記載の移動物体検出装置。
          With three ultrasonic receivers,
    The moving object detection apparatus according to claim 3, wherein the three ultrasonic receivers are arranged so that all the intervals are equal to each other.
PCT/JP2012/002396 2011-04-26 2012-04-05 Moving object detection device WO2012147284A1 (en)

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EP2908153A3 (en) * 2014-02-14 2016-01-13 Volkswagen Aktiengesellschaft Detection of dynamic objects by means of ultrasound
US20190204432A1 (en) * 2018-01-04 2019-07-04 Auspion, Inc. Three-dimensional and four-dimensional mapping of space using microwave and mm-wave parallax

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JP2010151496A (en) * 2008-12-24 2010-07-08 Nippon Soken Inc Azimuth detection device

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JP2003139855A (en) * 2001-11-05 2003-05-14 Koden Electronics Co Ltd Ultrasonic probing apparatus
JP2006343309A (en) * 2005-05-09 2006-12-21 Nippon Soken Inc Obstacle detector
JP2010151496A (en) * 2008-12-24 2010-07-08 Nippon Soken Inc Azimuth detection device

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP2908153A3 (en) * 2014-02-14 2016-01-13 Volkswagen Aktiengesellschaft Detection of dynamic objects by means of ultrasound
US20190204432A1 (en) * 2018-01-04 2019-07-04 Auspion, Inc. Three-dimensional and four-dimensional mapping of space using microwave and mm-wave parallax

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