JPH09145839A - Obstacle detecting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize d>=λ/2 without damaging the detecting accuracy when the interval of receivers is (d) and the wavelength of a supersonic wave is λ, by providing plural receivers and transmitting supersonic waves to different measuring regions and at different times from the receivers. SOLUTION: Receivers 12, 14 convert an electric signal to a supersonic wave to be transmitted to different measuring regions 12a, 12b different from each other, and a supersonic wave transmitting means 16 transmits supersonic waves from the receivers 12,14 at different times. A receiver array where receivers 861-868 are disposed converts a supersonic wave to an electric signal, and the converted electric signal is stored as received data by a supersonic wave receiving means 90. According to the received data stored in the supersonic wave receiving means 90, the position of an obstacle is calculated by an arithmetic means 20. Thus, when the interval (d) of the receivers 861-868 is (d) and the wavelength of a supersonic wave is λ, d>=λ/2 can be realized.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an obstacle detection device mounted on, for example, an automobile and detecting an obstacle by ultrasonic waves.

[0002]

2. Description of the Related Art FIG. 8 is a block diagram showing a conventional obstacle detecting device. Hereinafter, description will be given with reference to this drawing.

A conventional obstacle detecting device 80 is a wave transmitter 82 for converting an electric signal into an ultrasonic wave, an ultrasonic wave transmitting means 84 for transmitting an ultrasonic wave from the wave transmitter 82, and an ultrasonic wave into an electric signal. The wave receiver array 88 in which the wave receivers 861 to 868 are arranged, and the ultrasonic wave receiving means 9 for storing the electric signals converted by the wave receivers 861 to 868 as predetermined reception data.
0 and an arithmetic means 92 for calculating the position of the obstacle based on the reception data stored in the ultrasonic wave receiving means 90. The distance d between the wave receivers 861 to 868 is d <λ / 2, where λ is the wavelength of the ultrasonic wave.

The ultrasonic wave transmitting means 84 is a burst wave generating circuit. The ultrasonic wave receiving means 90 includes a filter circuit 931.
To 938, amplifier circuits 941 to 948, A / D conversion circuit 9
51 to 958, memories 961 to 968 and the like. The calculation means 92 is a microcomputer. The calculating means 92 and the memories 961 to 968 are connected to the bus 9
7 are connected.

The ultrasonic wave transmitted from the wave transmitter 82 is reflected by an obstacle (not shown), enters the wave receivers 861 to 868, and is converted into an analog signal. This analog signal is
Noise and the like are removed by the filter circuits 931 to 938, amplified by the amplifier circuits 941 to 948, and then converted into digital signals by the A / D conversion circuits 951 to 958. This digital signal is stored in the memories 961 to 968 as received data. The computing means 92 calculates the distance to the obstacle based on the time from the transmission from the wave transmitter 82 to the reception by the wave receivers 861 to 868, and the wave receivers 861 to 868.
The direction of the obstacle is calculated based on the phase difference of the reception at.

FIG. 9 is a graph showing an example of characteristic data created by the beam forming process of the computing means 92. Hereinafter, description will be given with reference to FIGS. 8 and 9. Here, in FIG. 8, the positive direction of the x-axis is the yaw angle 0 °, the positive direction of the y-axis is the yaw angle 90 °, and the negative direction of the y-axis is the yaw angle −90 °.

In FIG. 9, the horizontal axis represents the incident angle of ultrasonic waves, and the vertical axis represents the receiving sensitivity to ultrasonic waves. The characteristic data 100 shown in (a) has a main lobe 101 for an ultrasonic wave incident from a yaw angle of 60 °. The characteristic data 102 shown in (b) has a main lobe 103 for an ultrasonic wave incident from a yaw angle of 30 °. The characteristic data 104 shown in (c) has a main lobe 105 for an ultrasonic wave incident from a yaw angle of 0 °. The characteristic data 106 indicated by the broken line indicates the directivity of the wave receivers 861 to 868 alone. The main lobes 101, 103, 105 change along the characteristic data 106 according to the yaw angle. In addition,
The characteristic data 100, 102, 104, 106 are normalized so that the reception intensities at the yaw angle of 0 ° match.

A function having such characteristic data is created for each direction in the beam forming process. Then, by inputting the received data stored in the memories 961 to 968 to each function, a composite signal output for each function is obtained. If this combined signal output has a peak and its level is higher than a predetermined constant value, the yaw angle corresponding to the main lobe of the characteristic data of the function is the direction of the obstacle.

[0009]

SUMMARY OF THE INVENTION Receivers 861 to 868
As described above, the distance d is d <λ / 2. This is because the following problems occur when d ≧ λ / 2. FIG. 10 is a graph showing an example of characteristic data created by the beam forming process of the calculating means 92 when d = λ. Hereinafter, description will be given with reference to FIGS. 8 and 10. However, the same parts as those in FIG.

The characteristic data 108 shown in (a) is the yaw angle.
It has a main lobe 101 for ultrasonic waves incident from 60 ° and a grating lobe 109 for ultrasonic waves incident from a yaw angle of -30 °. The characteristic data 110 shown in (b) has a main lobe 103 for an ultrasonic wave incident from a yaw angle of 30 ° and a grating lobe 111 for an ultrasonic wave incident from a yaw angle of -60 °. The characteristic data 112 shown in (c) is
Main lobe 1 for ultrasonic waves incident from a yaw angle of 0 °
05, and grating lobes 113 and 114 for the ultrasonic waves incident from a yaw angle of ± 85 °. Since the grating lobes 113 and 114 are small, there is no particular problem. Grating lobes 109 and 111
Is as large as the main lobes 108, 110. This is because, for example, in the case of (b), when an ultrasonic wave incident from a yaw angle of 30 ° is detected, the yaw angle of −60 ° is detected.
Ultrasonic waves that are incident from are also detected. Therefore, the detection accuracy of the obstacle is significantly reduced.

On the other hand, the distance d between the wave receivers 861 to 868 is
For the following reason, it should be as large as possible, that is, d ≧ λ /
2 is desired.

[0012] Especially in the air, the wavelength λ of ultrasonic waves is extremely short. Therefore, it is necessary to make the distance d extremely small. Therefore, the wave receivers 861 to 868 must be small and highly sensitive. However, the development of the wave receivers 861 to 868 satisfying such conditions is
It is very difficult with the current technology, so the cost is high.

.. The length from the wave receiver 861 to the wave receiver 868 is called the aperture length of the wave receiver array 88. In order to detect an obstacle with high resolution, it is necessary to narrow the beam width of the main lobe of the reception sensitivity by increasing the aperture length. However, if the aperture length is increased, d <λ / 2
Therefore, it is necessary to increase the number of wave receivers 861, ... This is accompanied by an increase in not only the wave receivers 861, ... But also the filter circuits 931 ,.
This leads to an increase in size and cost of the device.

[0014]

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a wave receiver 861.
An object of the present invention is to provide an obstacle detection device capable of setting a distance d of ˜868 to d ≧ λ / 2.

[0015]

An obstacle detecting apparatus according to claim 1 is provided with a plurality of wave transmitters for converting electric signals into ultrasonic waves and transmitting the ultrasonic waves to different measurement areas, and a plurality of wave transmitters from these wave transmitters. Ultrasonic wave transmitting means for transmitting sound waves at different times, a wave receiver array in which a plurality of wave receivers for converting ultrasonic waves into electric signals are arranged, and the electric signals converted by the respective wave receivers are set to predetermined values. The ultrasonic wave receiving means stores the received data, and the calculating means calculates the position of the obstacle based on the received data stored in the ultrasonic wave receiving means.

An obstacle detecting apparatus according to a second aspect of the present invention is a wave transmitter for converting an electric signal into an ultrasonic wave, a wave transmitter rotating means for rotating the wave transmitter, and a wave transmitter rotating means. Ultrasonic wave transmitting means for rotating the wave transmitter via the to transmit ultrasonic waves to different measurement regions, a wave receiver array in which a plurality of wave receivers for converting the ultrasonic waves into electric signals are arranged, The ultrasonic wave reception means stores the electric signal converted by each wave receiver as predetermined reception data, and the calculation means calculates the position of the obstacle based on the reception data stored in the ultrasonic reception means. It is a thing.

An obstacle detecting apparatus according to a third aspect is the obstacle detecting apparatus according to the first or second aspect, in which a plurality of wave transmitters are provided instead of the wave transmitters. It was done.

An obstacle detecting apparatus according to a fourth aspect of the present invention includes a wave transmitter for converting an electric signal into an ultrasonic wave, an ultrasonic wave transmitting means for transmitting an ultrasonic wave from the wave transmitter, and an ultrasonic wave into an electric signal. A plurality of wave receiver arrays each having a plurality of wave receivers having different measurement regions, and an ultrasonic wave receiving means for storing the electric signal converted by each wave receiver as predetermined reception data, The ultrasonic wave receiving means is provided with a calculating means for calculating the position of the obstacle based on the received data.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a block diagram showing a first embodiment of an obstacle detecting device according to the present invention. FIG.
It is a schematic plan view which shows the measurement area | region of the wave transmitter in the obstacle detection apparatus of FIG. Hereinafter, description will be given with reference to these drawings. However, the same parts as those in FIG.

The obstacle detecting apparatus 10 according to the present invention converts an electric signal into an ultrasonic wave to measure different measuring regions 12a,
14a (FIG. 2), ultrasonic transmitters 16 for transmitting ultrasonic waves from the transmitters 12, 14 at different times, and a receiver 8 for converting ultrasonic waves into electric signals.
The receiver array 18 in which 61 to 868 are arranged, the ultrasonic wave receiving means 90 for storing the electric signals converted by the wave receivers 861 to 868 as predetermined reception data, and the ultrasonic wave receiving means 90 are stored. The calculation means 20 calculates the position of the obstacle based on the received data. Receiver 861
The interval d of 868 is d ≧ λ, where λ is the wavelength of the ultrasonic wave.
/ 2.

The axis of the wave transmitter 12 is directed to the measurement area 12a,
By orienting the axis of the transmitter 14 toward the measurement area 14a,
Different measurement areas 12a, 14 for the transmitters 12, 14
a is given. The ultrasonic wave transmission means 16 is composed of, for example, two burst wave generation circuits corresponding to the wave transmitters 12 and 14. The calculation means 20 is, for example, a microcomputer, DSP or the like. 1 and 2, the positive direction of the x-axis is the yaw angle 0 °, the positive direction of the y-axis is the yaw angle 90 °, and the negative direction of the y-axis is the yaw angle −90 °. The measurement area 12a has a yaw angle of approximately 0 to 90 °, and the measurement area 14a has a yaw angle of approximately 0.
~ -90 °.

Next, an example of the operation of the obstacle detecting device 10 will be described.

First, the calculating means 20 outputs a signal for generating ultrasonic waves from the wave transmitter 12 to the ultrasonic wave transmitting means 16. The ultrasonic wave generated from the wave transmitter 12 is transmitted toward the measurement region 12a, reflected by an obstacle (not shown), and incident on the wave receivers 861 to 868. Receivers 861 to 86
The ultrasonic waves entering 8 are converted into electric signals and stored in the memories 961 to 968 as reception data. Then, the position of the obstacle in the measurement area 12a is calculated by the calculation means 20 based on the received data. For example, the distance to the obstacle is calculated based on the time from transmission from the wave transmitter 12 to reception by the wave receivers 861 to 868.
The direction of the obstacle is calculated based on the phase difference of the reception at 1 to 868. Next, the calculation means 20 outputs a signal for generating ultrasonic waves from the wave transmitter 14 to the ultrasonic wave transmission means 16. Thereafter, the position of the obstacle in the measurement area 14a is calculated in the same manner.

FIG. 3 shows the calculating means 2 when d = λ.
7 is a graph showing an example of characteristic data created by a beamforming process of 0. Hereinafter, description will be made with reference to FIGS. However, the same parts as those in FIG.

The characteristic data 108, 110 and 112 have the same shape as that shown in FIG.
, And grating lobes 109 ,. In (a), (b), and (c), the transmitter 12
12b is added. The range of the directivity 12b is almost equal to that of the measurement area 12a. Within the range of the directivity 12b, only the main lobes 101, ... Exist and the grating lobes 109 ,. For example, in the case of (b), it is assumed that an ultrasonic wave incident from a yaw angle of 60 ° is detected while an ultrasonic wave incident from a yaw angle of 30 ° is detected. At this time, the ultrasonic wave incident from the yaw angle of −60 ° is outside the range of the directivity 12b, so that it can be easily determined that it is a virtual image. Similarly, the transmitter 14 can easily determine the virtual image. Therefore, even if d = λ, the obstacle can be accurately detected.

In the present embodiment, by setting d = λ, the grating lobes 109, ...
Since it occurs about 90 ° away from 01, ...
There are two a and 12b. By setting d> λ, when the grating lobe occurs within 90 ° from the main lobe, the measurement area may be increased accordingly.

FIG. 4 is a block diagram showing a second embodiment of the obstacle detecting device according to the present invention. Hereinafter, description will be given with reference to this drawing. However, the same parts as those in FIG.

The obstacle detecting device 30 according to the present invention comprises a wave transmitter 32 for converting an electric signal into an ultrasonic wave, a wave transmitter rotating means 34 for rotating the wave transmitter 32, and a wave transmitter rotation. The wave transmitter 32 is rotated via the means 34 to measure the measurement regions 12a, 14a.
Ultrasonic wave transmitting means 36 for transmitting ultrasonic waves to (FIG. 2),
A wave receiver array 18 in which a plurality of wave receivers 861 to 868 for converting ultrasonic waves into electric signals are arranged, and wave receivers 861 to 86
The ultrasonic wave reception means 90 stores the electric signal converted in 8 as predetermined reception data, and the calculation means 20 that calculates the position of the obstacle based on the reception data stored in the ultrasonic wave reception means 90. .

The wave transmitter rotating means 34 is, for example, a rotary platform for rotating the wave transmitter 32 in the yaw angle direction. The ultrasonic wave transmission means 36 is composed of, for example, a burst wave generation circuit of the wave transmitter 32 and a drive circuit of the rotary platform. In this embodiment,
It differs from the first embodiment in that the wave transmitter 32 is rotated via the wave transmitter rotating means 34 to transmit ultrasonic waves to the measurement regions 12a and 14a (FIG. 2). That is, the ultrasonic wave is transmitted with the axis of the wave transmitter 32 toward the measurement region 12a, and then the ultrasonic wave is transmitted with the axis of the wave transmitter 32 toward the measurement region 14a.
Therefore, this embodiment also has the same operation and effect as the first embodiment.
It works.

FIG. 5 is a block diagram showing a third embodiment of the obstacle detecting device according to the present invention. FIG. 6 is a schematic diagram showing a measurement region of the wave transmitter in the obstacle detection device of FIG. Hereinafter, description will be given with reference to these drawings. However,
1 are denoted by the same reference numerals, and redundant description is omitted.

The obstacle detecting device 40 according to the present invention is a wave transmitter 421 to 425, 441 for converting an electric signal into an ultrasonic wave.
To 445 and different measurement areas 4
2a, 44a (FIG. 6), ultrasonic wave transmitter arrays 42, 44, ultrasonic wave transmitting means 46 for transmitting ultrasonic waves from the ultrasonic wave transmitter arrays 42, 44 at different times, and ultrasonic wave electric signals. A receiver array 18 in which wave receivers 861 to 868 for converting into an ultrasonic wave are arranged, an ultrasonic wave receiving means 90 for storing the electric signal converted in the wave receivers 861 to 868 as predetermined reception data, and an ultrasonic wave. The calculation means 48 calculates the position of the obstacle based on the reception data stored in the reception means 90. The distance d between the wave receivers 861 to 868 is d ≧ λ / 2, where λ is the wavelength of the ultrasonic wave.

By orienting the axis of the wave transmitter array 42 toward the measurement area 42a and the axis of the wave transmitter array 44 toward the measurement area 44a, different measurement areas 42a and 44a for the wave transmitter arrays 42 and 44 are obtained. Granted. The ultrasonic wave transmission means 46 is composed of, for example, two burst wave generation circuits 461 and 462 corresponding to the wave transmitter arrays 42 and 44. The calculation means 48 is, for example, a microcomputer, DSP or the like.

5 and 6, the positive direction of the x-axis is 0 °, the positive direction of the y-axis is 90 °, the negative direction of the y-axis is −90 °, and the positive direction of the x-axis is positive. The pitch angle is 0 °, the positive direction of the z axis is 90 °, and the negative direction of the z axis is −90 °. The measurement area 42a has a yaw angle of approximately 0 to 90 degrees, and the measurement area 44a has a yaw angle of approximately 0 to -90 degrees. The transmitter arrays 42 and 44 include measurement areas 42a and 44a, respectively.
The fan-shaped ultrasonic beam shown as is transmitted. These ultrasonic beams are called transmitting fan beams, and the transmitter 42
By the phase control of the burst waves added to 1 to 428 and 441 to 448, the burst waves are freely moved in the directions indicated by arrows 42u, 42d, 44u and 44d. Therefore, the measurement area 42
a and 44a can be swung in the range of about −90 ° to 90 ° in pitch angle.

In a moving body such as an automobile, if the region where an obstacle is to be detected is made to have a conical shape, an object which does not become an obstacle higher than the vehicle height, for example, an echo such as a ceiling of a tunnel or a streetlight is picked up. Further, if the beam width of the ultrasonic wave is narrowed down so as not to pick up such an echo, the information in the left and right directions is reduced, which causes troubles when trying to bend a curve. Therefore, it is preferable that the region in which the obstacle is to be detected has an elliptical cone shape that is wide in the yaw direction when viewed from the moving body (that is, the vertical direction is narrow and the horizontal direction is wide).
The obstacle detection device 40 of the present embodiment is suitable for automobiles because it can easily transmit such an elliptical cone-shaped transmitted fan beam.

In this embodiment, the wave transmitters 12 and 14 in the first embodiment shown in FIG. 1 are replaced with wave transmitter arrays 42 and 44. Of course, the wave transmitter 32 in the second embodiment of FIG. 4 may be replaced with the wave transmitter array 42.

FIG. 7 is a block diagram showing a fourth embodiment of the obstacle detecting device according to the present invention. Hereinafter, description will be given with reference to these drawings. However, the same parts as those in FIG. 1 and FIG.

The obstacle detecting device 50 according to the present invention includes a wave transmitter 82 for converting an electric signal into an ultrasonic wave, an ultrasonic wave transmitting means 84 for transmitting an ultrasonic wave from the wave transmitter 82, and an ultrasonic wave as an electric signal. 511-518, 521-52 for converting to
8 are arranged and different measurement areas 12a,
14a (FIG. 2) and ultrasonic wave receiving means 901 and 902 for storing the electric signals converted by the wave receivers 511 to 518 and 521 to 528 as predetermined reception data; The calculation means 54 calculates the position of the obstacle based on the reception data stored in the sound wave reception means 901 and 902. Wave receivers 511-518,5
If the wavelength of the ultrasonic wave is λ, the interval d of 21 to 528 is
d ≧ λ / 2.

By orienting the axis of the wave receiver array 51 toward the measurement area 12a and the axis of the wave receiver array 52 toward the measurement area 14a, different measurement areas 12a and 14a for the wave receiver arrays 51 and 52 are obtained. Granted. The ultrasonic wave receiving means 901 and 902 have the same configuration as the ultrasonic wave receiving means 90 in FIG. The calculation means 54 is, for example, a microcomputer, a DSP, or the like.

[0039]

According to the obstacle detecting apparatus of the first aspect, a plurality of wave transmitters are provided, and ultrasonic waves are transmitted from these wave transmitters at different measurement areas and times, so that the ultrasonic wave can be detected outside the measurement area. Virtual images can be easily eliminated. According to the obstacle detection device of the second aspect, a wave transmitter rotating means for rotating the wave transmitter is provided, and the ultrasonic wave is transmitted from the wave transmitter to a different measurement region and at a different time. The virtual image of can be easily eliminated. According to the obstacle detection device of the fourth aspect, since the plurality of wave receiver arrays having different measurement regions are provided, the virtual image outside the measurement region can be easily eliminated.

Therefore, according to the obstacle detecting device of the present invention, the distance between the wave receivers can be increased without lowering the detection accuracy. Therefore, since it is not necessary to downsize the wave receiver, the existing wave receiver can be used. In addition, since the aperture length of the receiver array can be increased without increasing the number of receivers, the resolution can be improved without increasing the number of signal processing circuits.

According to the obstacle detection device of the third aspect,
By arraying the wave transmitters, the measurement region can be formed in an elliptical cone shape having a narrow vertical direction and a wide horizontal direction, and thus can be suitably used for an automobile or the like.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a first embodiment of an obstacle detection device according to the present invention.

FIG. 2 is a schematic plan view showing a measurement region of a wave transmitter in the obstacle detection device of FIG.

FIG. 3 is a graph showing an example of characteristic data created by a beam forming process of a computing unit in the obstacle detection device of FIG.

FIG. 4 is a block diagram showing a second embodiment of an obstacle detection device according to the present invention.

FIG. 5 is a block diagram showing a third embodiment of an obstacle detection device according to the present invention.

6 is a schematic view showing a measurement region of a wave transmitter in the obstacle detection device of FIG. 5, FIG. 6 (a) is a front view, and FIG.
(B) is a plan view.

FIG. 7 is a block diagram showing a fourth embodiment of an obstacle detection device according to the present invention.

FIG. 8 is a block diagram showing a conventional obstacle detection device.

9 is a graph showing an example of characteristic data created by a beam forming process of a computing unit in the obstacle detection device of FIG.

FIG. 10 is a graph showing an example of characteristic data created by a beam forming process of a computing unit in a conventional obstacle detection device.

[Explanation of symbols]

10, 30, 40, 50 Obstacle detection device 12, 14, 32, 82, 421-425, 441-4
45 wave transmitter 12a, 14a, 42a, 44a measurement area 16, 36, 46, 84 ultrasonic wave transmitting means 18, 51, 52 wave receiver array 20, 48, 54 computing means 34 wave transmitter rotating means 42, 44 Wave transmitter array 511 to 518, 521 to 528, 861 to 868 Wave receiver 90, 901, 902 Ultrasonic wave receiving means d Interval between wave receivers

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display location G01S 15/93 G01S 15/93

Claims (4)

[Claims] 1. A plurality of wave transmitters for converting electric signals into ultrasonic waves and transmitting them to different measurement regions, ultrasonic wave transmitting means for transmitting ultrasonic waves from these wave transmitters at different times, and ultrasonic waves. A wave receiver array in which a plurality of wave receivers for converting the electric signals are arranged, and an ultrasonic wave receiving means for storing the electric signals converted by the respective wave receivers as predetermined reception data,
An obstacle detection device comprising: an arithmetic means for calculating the position of the obstacle based on the reception data stored in the ultrasonic wave reception means. 2. A wave transmitter for converting an electric signal into an ultrasonic wave,
A wave transmitter rotating means for rotating the wave transmitter; an ultrasonic wave transmitting means for rotating the wave transmitter via the wave transmitter rotating means to transmit ultrasonic waves to different measurement regions; A wave receiver array having a plurality of wave receivers for converting sound waves into electric signals, an ultrasonic wave receiving means for storing the electric signals converted by the wave receivers as predetermined reception data, and the ultrasonic wave An obstacle detection device comprising: an arithmetic unit that calculates the position of an obstacle based on the reception data stored in the reception unit. 3. The obstacle detection device according to claim 1 or 2, which is a wave transmitter array in which a plurality of the wave transmitters are arranged instead of the wave transmitter. 4. A wave transmitter for converting an electric signal into an ultrasonic wave,
Ultrasonic transmitting means for transmitting ultrasonic waves from this transmitter,
A plurality of wave receivers for converting ultrasonic waves into electric signals are arranged and a plurality of wave receiver arrays having different measurement areas, and the electric signals converted by the respective wave receivers are stored as predetermined reception data. An obstacle detection device comprising: an ultrasonic wave receiving means for calculating the position of an obstacle based on received data stored in the ultrasonic wave receiving means.