JP2020180806A - Object detection device - Google Patents

Abstract

To provide an object detection device capable of improving accuracy of object detection.SOLUTION: An object detection device includes a transmission unit 10 that transmits an ultrasonic wave as a probe wave in response to a drive signal input from a signal generation unit 20, a reception unit 50 that receives the ultrasonic wave and generates a reception signal, a horizontal position acquisition unit 72 that acquires a position of an object in a horizontal direction with respect to the transmission unit, and a signal determination unit 70 that determines detection of the object based on the reception signal and the position of the object. The reception unit receives reflected waves of at least two search waves having different directivity. The signal determination unit calculates a height of the object based on the reception signal and the position of the object, and determines that the object is present when the height is equal to or greater than a predetermined threshold.SELECTED DRAWING: Figure 1

Description

The present invention relates to an object detection device that detects an object by transmitting and receiving ultrasonic waves.

Conventionally, as this type of device, for example, the object detection device described in Patent Document 1 has been proposed. This object detection device is mounted on a vehicle and transmits two types of transmitted waves with different vertical directivity with a time difference, a receiving unit that receives reflected waves, and a frequency component derived from each transmitted wave from the reflected waves. It includes an extraction unit for extracting and a detection unit for detecting an object from a frequency component.

This object detection device reaches the road surface after transmitting the first transmitted wave having a predetermined reach and before receiving the reflected wave, and has a wider reach than the first transmitted wave. It is configured to transmit the transmitted wave of 2 and receive these reflected waves. Further, the amplitude level of the first transmitted wave is set so that the reception level of the reflected wave from the road surface at a predetermined distance from the vehicle is equal to or less than the predetermined reference value, while the amplitude level of the second transmitted wave is set. , The reception level of the reflected wave from the road surface is set to be higher than the predetermined reference value. Then, this object detection device extracts the frequency component of each transmitted wave from the received reflected wave, recognizes the reflected wave from the road surface by the time when the reflected wave is received, and receives the frequency component of each transmitted wave. Detects obstacles on the road surface.

JP-A-2018-54581

In this type of object detection device, it is required to further improve the object detection accuracy. For example, the above-mentioned object detection device uses two types of transmitted waves having different vertical directivity, and can detect obstacles having a predetermined height or higher in the front direction of the transmitting unit, but these transmitted waves are horizontally directional. If they are different, the accuracy of detecting obstacles in the horizontal direction may be insufficient.

Specifically, when the horizontal directivity of the two types of transmitted waves is different, for example, an object in the front direction with respect to the transmitting unit and an object in the diagonally forward direction have different reflected waves from the respective objects. The reception level changes. That is, when the horizontal position of the object with respect to the transmitting unit changes, the reception level of the reflected wave from the object also changes. Therefore, in order to detect an object having a predetermined height or higher at different horizontal positions, the horizontal position is used. The reference value of the reception level must be changed according to the direction position. However, it is not possible to consider this change in the horizontal position only by transmitting two types of transmitted waves having different frequencies, and it is not possible to secure the detection accuracy of an object other than the front direction.

In view of the above points, it is an object of the present invention to provide an object detection device in which the detection accuracy of the height of an object is higher than before in the horizontal direction as well as in the vertical direction with respect to the transmitting unit.

In order to achieve the above object, the object detection device according to claim 1 is an object detection device (1) mounted on a moving body to detect an object, and has a signal generation unit (20) for generating a drive signal. , A transmitter (10) that transmits ultrasonic waves as a search wave according to the input drive signal, a receiver (50) that receives ultrasonic waves and generates a received signal, and an object in the horizontal direction with respect to the transmitter. A horizontal position acquisition unit (72) for acquiring a position and a signal determination unit (70) for detecting and determining an object based on a received signal and the position of the object are provided, and the receiving unit has at least two different directional directions. Upon receiving the reflected wave of the exploration wave, the signal determination unit calculates the height of the object based on the received signal and the position of the object, and determines that the object exists when the height is equal to or greater than a predetermined threshold value.

According to this, in addition to the received signal obtained by transmitting and receiving two exploration waves having different directivity, the object detection device having a configuration in which the horizontal position of the object is acquired by the horizontal position acquisition unit and the height of the object is calculated. Become. Then, by acquiring the horizontal position of the object by the horizontal position acquisition unit, the height is calculated based on the received signal obtained by transmitting and receiving two types of exploration waves having different directivity, according to the horizontal position of the object. The reference value of the reception level can be changed. That is, even if the horizontal orientations are different, the reference value in the object height calculation can be changed according to the horizontal position, so that the object height calculation accuracy is high and the object detection accuracy is higher than before. It becomes.

The reference reference numerals in parentheses attached to each component or the like indicate an example of the correspondence between the component or the like and the specific component or the like described in the embodiment described later.

It is a block diagram which shows the structure of the object detection apparatus of 1st Embodiment. It is a figure which shows an example of the amplitude and frequency of a drive signal. It is a figure which shows an example of the directivity of a transmitter / receiver. It is a figure for demonstrating the relationship between the position of an object, and the vertical direction. It is a figure for demonstrating the relationship between the position of an object, and the horizontal direction. It is a figure which shows another example of the directivity of a transmitter / receiver. It is a figure which shows an example of the reach range of two kinds of exploration waves with different frequencies. It is a figure which shows the amplitude of the reflected wave when the exploration wave with a wide vertical directivity is transmitted. It is a figure which shows the amplitude of the reflected wave when the exploration wave with narrow vertical directivity is transmitted. It is a figure which shows the relationship between the horizontal distance from a transmitter / receiver, and a vertical direction. It is a figure which shows the relationship between the horizontal distance from a transmitter / receiver, and the amplitude ratio. It is a figure which shows the reference value of determination and the detection range. It is a figure which shows an example of the amplitude of the reflected wave when the exploration wave with a wide vertical directivity is transmitted to two detection targets having different horizontal directions. It is a figure which shows an example of the amplitude of the reflected wave when the exploration wave with narrow vertical directivity is transmitted to two detection targets having different horizontal directions. It is a figure which shows an example of the vertical directivity at a high and low frequencies. It is a figure which shows an example of the horizontal directivity at a high and low frequencies. 15 is a diagram showing the relationship between the frequency ratio for each horizontal direction and the height of an object, which is calculated based on the high and low frequencies having directivity in FIGS. 15 and 16. It is a figure which shows the transmission of the exploration wave to the detection target by one sonar. It is a figure which shows the transmission of the exploration wave to the detection target by two sonars. It is a flowchart which shows the operation processing example of the object detection apparatus of FIG. It is a figure for demonstrating the extraction method of an analysis range and an amplitude. It is a figure which shows the relationship between the linear distance from a transmitter / receiver, and the attenuation amount of an amplitude level. It is a figure which shows the difference of the amplitude level when the frequency difference is small. It is a figure which shows the difference of the amplitude level when the frequency difference is large. It is a figure which shows the frequency characteristic of a transmitter / receiver. It is a figure which shows the frequency characteristic of a transmitter / receiver. It is a block diagram which shows the structure of the object detection apparatus of 2nd Embodiment. It is a block diagram which shows the structure of the object detection device of 3rd Embodiment. It is a block diagram which shows the structure of the object detection apparatus of 4th Embodiment. It is a block diagram which shows the example which the transmitter and the receiver are separated.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In each of the following embodiments, parts that are the same or equal to each other will be described with the same reference numerals.

(First Embodiment)
The object detection device 1 of the first embodiment will be described with reference to FIGS. 1 to 26.

〔Constitution〕
As shown in FIG. 1, the object detection device 1 of the present embodiment has two sonar units 100 including a transmission unit 10, a signal generation unit 20, a transmitter / receiver 30, a reception unit 50, and a frequency separation unit 60. Along with this, a control unit 40 and a signal determination unit 70 are provided.

In the present embodiment, in the object detection device 1, the control unit 40 performs drive control of the two sonar units 100, and the amplitude value obtained by these sonar units 100 is output to the signal determination unit 70 and a signal. The determination unit 70 is configured to detect and determine an object based on the amplitude value. The object detection device 1 is an ultrasonic sonar device, which is mounted on a moving body such as a vehicle to detect an object outside the moving body. In this embodiment, an example mounted on a vehicle such as an automobile will be described.

In the present embodiment, for convenience of explanation, the one mounted in the first position of the two sonar portions 100 is referred to as "first sonar portion 100A" and mounted in a second position different from the first position. The thing may be referred to as "second sonar part 100B". Arrangement-related information such as the coordinates of the sonar units 100A and 100B is stored in advance in a storage medium described later.

The transmission unit 10 transmits ultrasonic waves as exploration waves, and is composed of a transmission circuit 11 and a transmitter / receiver 30 as shown in FIG. The transmission unit 10 has a configuration in which a drive signal from the signal generation unit 20 is input to the transmission circuit 11, and transmits an exploration wave corresponding to the drive signal input from the signal generation unit 20. The drive signal is an electric signal for driving the transmitter / receiver 30, has a frequency corresponding to the frequency of the exploration wave, and is, for example, an AC signal that changes in a predetermined pattern with the passage of time.

The signal generation unit 20 generates a pulse signal having a frequency in the ultrasonic band as a drive signal. The signal generation unit 20 generates a drive signal having at least two frequencies. For example, as shown in FIG. 2, the signal generation unit 20 intermittently generates a signal having a frequency f _{H and} a signal having a frequency f _L (<f _H ). The drive signal generated by the signal generation unit 20 is input to the transmission circuit 11 as shown in FIG. The signal generation unit 20 transmits transmission instructions, drive signal setting information, and the like from the control unit 40, which will be described later.

The transmission circuit 11 performs processing such as boosting on the drive signal input from the signal generation unit 20, and outputs the signal generated thereby. The output signal of the transmission circuit 11 is input to the transmitter / receiver 30.

The transmitter / receiver 30 functions as a part of the transmission unit 10 and transmits an exploration wave toward the outside of the vehicle in response to a signal input from the transmission circuit 11. The transmitter / receiver 30 is composed of, for example, a microphone including an electromechanical conversion element (for example, a piezoelectric element) that is excited by being driven by a drive signal. The transmitter / receiver 30 also functions as a part of the receiving unit 50, and outputs a voltage corresponding to the sound pressure of the received wave.

The receiving unit 50 receives ultrasonic waves and generates a receiving signal according to the sound pressure of the received wave, and is composed of a transmitter / receiver 30 and a receiving circuit 51 as shown in FIG. The received signal generated by the receiving unit 50 is input to the signal determination unit 70 after being processed by the frequency separation unit 60, and is used for object detection processing in the signal determination unit 70.

The receiving circuit 51 generates and outputs a received signal by subjecting the output voltage of the transceiver 30 to a process such as amplification. The received signal generated by the receiving circuit 51 is input to the frequency separation unit 60.

The frequency separation unit 60 performs processing such as filtering on the reception signal from the reception circuit 51, and outputs the signal generated by this processing. As shown in FIG. 1, the frequency separation unit 60 includes BPF 61a and 61b and amplitude generation units 62a and 62b.

BPF61a and 61b are bandpass filters that allow signals in a predetermined frequency band to pass through and block signals in other frequency bands. The bands of BPF61a and 61b are set by the input signal from the control unit 40. The center frequencies of the passing frequency bands of BPF61a and 61b are, for example, f _L and f _H , respectively. Among the received signals generated by the receiving circuit 51, the signals that have passed through the BPF 61a and 61b are input to the amplitude generating units 62a and 62b.

The amplitude generation units 62a and 62b calculate the amplitude value of the input signal. The amplitude value is, for example, the measured value of the zero to peak of the input signal, the measured value of the peak to peak of the input signal, the effective value of the input signal, the value obtained by envelope processing the input signal, the value obtained by converting the input signal to the average power, and the like. Any of these can be used.

The BPF 61a and 61b and the amplitude generators 62a and 62b extract two amplitudes corresponding to the two frequencies f _L and f _H from the received signal. In the following description, the amplitudes corresponding to the frequencies f _L and f _H will be referred to as A _L and A _H , respectively.

The signal determination unit 70 performs detection determination of an object based on a received signal, and is composed of an amplitude ratio calculation unit 71 and a horizontal position acquisition unit 72 as shown in FIG. The signal determination unit 70 determines that the object is based on the amplitude ratio, which is the ratio of the amplitude A _L and the amplitude A _H calculated by the amplitude ratio calculation unit 71, and the horizontal position of the object obtained by the horizontal position acquisition unit 72. Determine if it exists. Specifically, the signal determination unit 70 determines whether or not the height of the object calculated from the amplitude ratio and the horizontal position of the object is equal to or greater than a predetermined threshold value. The determination result of the signal determination unit 70 is transmitted to the control unit 40.

The threshold value used for calculating the height of the object based on the amplitude ratio described later is appropriately changed according to the horizontal position of the object acquired by the horizontal position acquisition unit 72. The reason for this and the details of the determination by the signal determination unit 70 will be described later. Further, the threshold value of the height of the object in the detection determination of the object may be changed as appropriate.

The amplitude ratio calculation unit 71 calculates, for example, Ar = A _H / A _L as the amplitude ratio based on the signal output from the frequency separation unit 60. The amplitude ratio calculated by the amplitude ratio calculation unit 71 is used for the detection determination of the object by the signal determination unit 70.

The horizontal position acquisition unit 72 acquires information on the horizontal position of the object with respect to the transmission unit 10. With the three-dimensional coordinates of the object to be detected as (x, y, z), the horizontal position acquisition unit 72 refers to x, y, z obtained by transmitting and receiving ultrasonic signals in the two sonar units 100 in the present embodiment. The horizontal position of the object is calculated based on the three mathematical formulas of.

For example, two of the three formulas are a function of "distance between an object and the transmitting unit 10 of the first sonar unit 100" obtained from the first sonar unit 100, and "amplitude difference or amplitude ratio of two frequencies". Is a function of. The remaining one formula is, for example, a function of "distance between an object and the transmitting unit 10 of the second sonar unit 100" obtained from the second sonar unit 100, or a function of "amplitude difference or amplitude ratio of two frequencies". Will be done. The details will be described later.

The control unit 40, the signal determination unit 70, etc. are configured by, for example, a well-known microcomputer equipped with a CPU, ROM, RAM, I / O, etc., and execute various operations and the like according to a program stored in the ROM, etc. .. The ROM and the like also include a rewritable non-volatile memory such as an EEPROM. ROMs and RAMs are non-transitional substantive storage media.

The above is the basic configuration of the object detection device 1 of the present embodiment.

Next, the object detection by the object detection device 1 will be described step by step.

[Calculation of straight line distance]
First, the calculation of the linear distance between an object and sonar by TOF (abbreviation of Time of Flight) will be described.

This type of object detection device can calculate the linear distance L between the object and the sonar based on the time from the transmission of the exploration wave from the sonar to the reception of the reflected wave, that is, the TOF. For example, when the exploration wave is an ultrasonic wave and the speed of sound is c, the linear distance L is calculated by the formula L = c × TOF / 2.

However, with this method, although the linear distance between the object and the sonar can be found, it is difficult to check the height of the object. Even if the linear distance between the object and the sonar is known, for example, the detected object is an obstacle such as a wall that may collide with the vehicle equipped with the object detection device, or collides with the vehicle body. It is not possible to determine whether the level difference is low or unlikely.

As a result of diligent studies, the present inventors have focused on the relationship between the frequency and directivity of the exploration wave, which is an ultrasonic wave, and devised a configuration that enables discrimination between an obstacle object and another object.

[Frequency and directivity of exploration waves]
Subsequently, the relationship between the frequency of the exploration wave and the directivity will be described with reference to FIGS. 3 to 7. In addition, in FIGS. 3 and 6, the amplitude level when the orientation described later is 0 ° is shown by a broken line. Further, the "road surface step" shown in FIG. 4 refers to a step having a small protrusion height from the road surface of the passage, such as a wheel chock, and needs to be detected as an "obstacle" that may collide with the vehicle body. Is a low object.

As shown in FIG. 3, for example, the transceiver 30 composed of a microphone or the like has a directivity characteristic in which the amplitude level of the exploration wave decreases as the vertical and horizontal directions increase.

As shown in FIG. 4, the vertical direction is determined by the angle formed by a horizontal plane having the vertical direction as the normal direction and passing through the transceiver 30 and a straight line connecting the transceiver 30 and an object. In the example shown in FIG. 4, the wall W1 located in front of the transmitter / receiver 30 has a vertical orientation of 0 °. The vertical direction of the road surface step is larger than 0 °. When the vehicle is located in a passage with a ceiling and there is a ceiling step such as a beam (not shown) on the ceiling, the vertical direction of the ceiling step is also larger than 0 °.

As shown in FIG. 5, the horizontal orientation is determined by the angle formed by the front direction of the transceiver 30 and the straight line connecting the transceiver 30 and the object in the horizontal plane passing through the transceiver 30. In the example shown in FIG. 5, the wall W1 and the road surface step located in front of the transmitter / receiver 30 have a vertical direction of 0 °. The wall W2 located diagonally forward of the transmitter / receiver 30 has a horizontal orientation larger than 0 °.

The amplitude level of the exploration wave traveling toward a height different from that of the transceiver 30 is smaller than that of the exploration wave traveling from the transceiver 30 in the direction parallel to the horizontal plane. Therefore, the amplitude level of the reflected wave from the object at a height different from that of the transmitter / receiver 30 is smaller than that of the reflected wave from the object located in front of the transmitter / receiver 30. This applies not only to the vertical orientation described above, but also to the horizontal orientation.

Here, it is known that the directivity characteristics change depending on the size of the transmission surface of the transmitter / receiver 30, the wavelength of the transmission wave, the vibration mode of the transmission surface, and the like. When the size of the transmission surface is constant, the directivity can be changed by changing the frequency of the transmission signal. Further, when the vibration modes are the same, in general, as shown in FIG. 3, f _H having a high frequency has a narrower directivity than f _L having a low frequency. When the frequency difference is small, the vibration modes are often the same.

However, if the frequency difference between the two types of exploration waves is large, the vibration mode of the transmitting surface may change, and the relationship between the high and low frequencies and the wide directivity may be reversed. Depending on the vibration mode, for example, as shown in FIG. 6, f _H having a high frequency may have a wider directivity than f _L having a low frequency.

Further, as shown in FIG. 3 or 6, the larger the vertical direction, the larger the difference in directivity due to the difference in frequency, and the smaller the vertical direction, the smaller the difference in directivity due to the difference in frequency. In other words, the larger the vertical orientation of the object, the larger the difference in the amplitude level of the reflected wave due to the difference in frequency, and the smaller the vertical orientation of the object, the smaller the difference in the amplitude level of the reflected wave due to the difference in frequency.

The in-vehicle object detection device 1 using a sonar attached to the vehicle has a narrow vertical directivity (vertical directivity) and a wide horizontal directivity (horizontal directivity). Can be set. In this case, as shown in FIGS. 3 and 6, the difference in directivity due to the difference in frequency appears in the vertical direction, and the difference in the horizontal direction is smaller than that in the vertical direction.

As described above, the mode of occurrence of the difference in the amplitude level of the received signal of the reflected wave due to the difference in the frequency of the exploration wave changes depending on the vertical orientation of the object. For example, when the transmitter / receiver 30 has the characteristics shown in FIG. 3, the range in which the exploration wave reaches changes as shown in FIG. 7 due to the difference in directivity due to the difference in frequency.

The region R _A shown in FIG. 7 is a reach of exploration waves of wide directivity lower frequency f _L. Region R _B is a reach of exploration wave of narrow directivity high frequency f _H. That is, the exploration wave having a wide vertical directivity easily reaches the road surface or the like in addition to the wall or the like in front of the transceiver 30. On the other hand, the exploration wave having a narrow vertical directivity reaches the wall in front of the transceiver 30, but it is difficult to reach a portion having a large vertical direction such as a road surface or a ceiling of a passage. Further, the high frequency and the low frequency referred to here mean the relative high and low frequencies.

[Object detection based on amplitude ratio]
The detection of an object based on the amplitude ratio will be described with reference to FIGS. 8 to 12. Here, the detection of an object at a horizontal direction of 0 ° will be described as a typical example.

In FIG. 11, the theoretical value (calculated value) when the object is a wall having a predetermined height or higher where there is a possibility of collision is shown by a broken line, and the theoretical value (calculated value) when the object is a road surface step is a dashed line. It is shown by. FIG. 12 _shows the amplitude ratio when the A H = _{A L} by a broken line.

When a search wave with a wide vertical directivity is transmitted, as shown in FIG. 8, the amplitude is increased between the reflected wave from the wall W1 in front of the transceiver 30 and the reflected wave from a step on the road surface or the like. It doesn't make a big difference. On the other hand, when a narrow vertical directivity exploration wave is transmitted, as shown in FIG. 9, between the reflected wave from the wall W1 in front of the transmitter / receiver 30 and the reflected wave from a step on the road surface or the like. There is a big difference in amplitude. Specifically, the amplitude of the reflected wave from the step on the road surface or the like is significantly smaller than that of the reflected wave from the wall W1 in front of the transmitter / receiver 30.

Utilizing the above properties, for use in the detection determination of the object, the amplitude ratio calculation unit 71 calculates the amplitude ratio Ar between the amplitude A _H of the amplitude A _L and the high frequency f _H of the lower frequency f _L. Then, the signal determination unit 70 determines whether or not the amplitude ratio Ar is equal to or greater than a predetermined reference value, or is equal to or less than a predetermined reference value, according to the directivity characteristics of the frequency f _L and the frequency f _H in the transceiver 30. Determine if it exists.

For example, as shown in FIG. 3, when the directivity of the frequency f _L in the transceiver 30 is wider than the directivity of the frequency f _H , the signal determination unit 70 has an amplitude ratio Ar of a predetermined reference value or more. Judge whether or not. On the other hand, as shown in FIG. 6, when the directivity of the frequency f _L in the transceiver 30 is narrower than the directivity of the frequency f _H , the signal determination unit 70 has an amplitude ratio Ar of not more than a predetermined reference value. Judge whether or not. In any of these cases, an affirmative judgment means that an object having a predetermined height or higher is within a predetermined detection range, and a negative judgment means that an object having a predetermined height or higher is within a predetermined detection range. It means being outside.

The "predetermined detection range" here is a region having a predetermined height and width around the directional axis of the transmitter / receiver 30. The "directed axis" is a straight line that substantially coincides with the locus of the point where the exploration wave intensity becomes the highest when the linear distance from the transmitter / receiver 30 is changed. The "directed axis" typically coincides substantially with the central axis of the transmitter / receiver 30. Further, the "predetermined height and width" may change depending on the linear distance from the transmitter / receiver 30. The cross-sectional shape of the "predetermined detection range" in the virtual plane orthogonal to the directional axis is typically circular.

Although the example in which the amplitude ratio Ar = A _H / A _L has been described above, the amplitude ratio Ar = A _L / A _H may be used. In this case, for example, when the directivity of the transmitter / receiver 30 is frequency f _H <frequency f _L , the signal determination unit 70 determines whether or not the amplitude ratio Ar is equal to or greater than a predetermined reference value. On the other hand, when the directivity of the transmitter / receiver 30 is frequency f _H > frequency f _L , the signal determination unit 70 determines whether or not the amplitude ratio Ar is equal to or less than a predetermined reference value. Even in this case, the affirmative judgment means that the object having a predetermined height or higher is within the predetermined detection range, and the negative judgment means that the object having a predetermined height or higher is not within the predetermined detection range. means.

It is also possible by using the amplitude ratio as _{AR = K × log (A H} / A L) = K × log (A H) -K × log (A L). The amplitude ratio AR may also be referred to as “logarithmic amplitude ratio AR”. The constant K is typically 20. When the constant K is 20, the logarithmic amplitude ratio AR can also be referred to as the "decibel difference". That is, the "amplitude ratio" is not limited to the arithmetic division value between two amplitudes, but is a concept including a decibel difference.

As shown in FIG. 10, the vertical direction of the road surface step increases as the horizontal distance from the transmitter / receiver 30 becomes shorter. Therefore, as shown in FIG. 11, the amplitude ratio of the reflected wave from the wall W1 in front of the transceiver 30 is substantially constant regardless of the horizontal distance from the transceiver 30. On the other hand, the amplitude ratio of the reflected wave from the road surface or the like becomes smaller as the horizontal distance from the transmitter / receiver 30 becomes shorter.

In consideration of this, the reference value to be compared with the amplitude ratio Ar is set so as to be smaller as the linear distance from the transmitter / receiver 30 is shorter, for example, as shown in FIG. The linear distance can be calculated based on the TOF. When the transmitter / receiver 30 has the characteristics shown in FIG. 3, the signal determination unit 70 determines whether or not the amplitude ratio Ar, that is, A _H / A _L is equal to or greater than a predetermined reference value. In the case of an affirmative judgment, it means that the object is within the detection range, and in the case of a negative judgment, it means that the object is out of the detection range.

The reverberation range shown in FIG. 11 is a range in which the reverberation of the transmitter / receiver 30 due to the transmission of the exploration wave is detected. When the linear distance measured from the TOF is shorter than a predetermined value, the signal determination unit 70 determines that the received signal is due to reverberation and does not determine the detection of the object.

[Correction by horizontal position in object detection]
The correction by the horizontal position in the object detection will be described with reference to FIGS. 13 to 17. In FIGS. 15 and 16, the directivity of the low frequency f _L is shown by the broken line, and the directivity of the high frequency f _H is shown by the alternate long and short dash line. FIG. 17 shows the result of simulating the relationship between the amplitude ratio and the height of the object calculated by this for each horizontal direction. The horizontal direction 0 ° is a solid line, the horizontal direction 30 ° is a broken line, and the horizontal direction is horizontal. 45 ° is indicated by a alternate long and short dash line.

In the above, it has been described that an object can be detected based on the amplitude ratio of these reflected waves by using two types of exploration waves having different directivity. However, if not only the vertical directivity but also the horizontal directivity are different in the two types of exploration waves, the amplitude level will change due to the difference in the horizontal position (horizontal direction) of the detection target, making it difficult to distinguish the object. Can be.

Specifically, as shown in FIG. 5, it is assumed that a step exists in the horizontal direction of 0 ° and the wall W2 exists in the horizontal direction of 20 °. In this case, when an exploration wave with wide directional is transmitted, the amplitude level changes depending on the horizontal direction. As a result, as shown in FIG. 13, the reflected wave from the step at 0 ° in the horizontal direction and the reflected wave at 20 ° in the horizontal direction There may not be a significant difference in amplitude between the reflected wave from the wall W2. Also, when a search wave with narrow directivity is transmitted, as shown in FIG. 14, between the reflected wave from the step at the horizontal direction of 0 ° and the reflected wave from the wall W2 at the horizontal direction of 20 °. Therefore, it is possible that there is no significant difference in amplitude.

That is, in this case, the amplitude ratio of the road surface step at 0 ° in the horizontal direction and the wall W2 at 20 ° in the horizontal direction are almost the same even though their heights are different. These objects cannot be discriminated only by the amplitude ratio.

Further, as shown in FIGS. 15 and 16, the present inventors take exploration waves of frequencies f _L and f _{H having} different vertical directivity and horizontal directivity as examples, and the frequency ratios of these reflected waves and the object. The correlation with height was simulated. As a result, as shown in FIG. 17, it was found that the height of the object differs depending on the horizontal orientation of the object even if the amplitude ratio is the same.

For example, when the amplitude ratio of 1.4 is used as a reference value, the signal determination unit 70 can detect an object having a height of 0.2 m or more in the case of a horizontal direction of 0 °, while the signal determination unit 70 can detect an object in a horizontal direction of 30 °. Can detect an object with a height of 0.5 m or more, but cannot detect an object with a height of less than 0.5 m.

This result means that it is necessary to appropriately change the reference value according to the horizontal direction in order to detect an object having the same predetermined height or higher when the horizontal directions are different. For example, when an object having a height of 0.2 m or more is detected in different horizontal directions, the reference value of the amplitude ratio is 1.4 for a horizontal direction of 0 ° and 3. for a horizontal direction of 30 °. 0, horizontal direction 45 ° needs to be 6.6.

Conversely, it is determined whether the calculated amplitude ratio is equal to or more than the reference value or less than the reference value after acquiring the horizontal position of the object and setting the reference value of the amplitude ratio according to the horizontal position of the object. Therefore, it is possible to detect an object having a predetermined height or higher in any horizontal direction.

Therefore, in order to detect an object having the same predetermined height or higher in different horizontal directions, the object detection device 1 of the present embodiment acquires the horizontal direction (horizontal position) of the object by the horizontal position acquisition unit 72, and responds accordingly. Therefore, the height of the object is calculated by correcting the reference value of the amplitude ratio.

The correlation data between the amplitude ratio for each horizontal direction and the height of the object is, for example, converted into a data table, stored in a storage medium, and read from the CPU as needed.

[Calculation of horizontal position by horizontal position acquisition unit]
The acquisition of the horizontal position of the object by the horizontal position acquisition unit 72 will be described with reference to FIGS. 18 and 19.

In FIGS. 18 and 19, for convenience, the three-dimensional coordinates of the object X to be detected are (x, y, z), and the three-dimensional coordinates of the first transmitter / receiver 30 constituting the first sonar unit 100A. Is (x1, y1, z1). In FIG. 19, the three-dimensional coordinates of the second transmitter / receiver 30 constituting the second sonar portion 100B are set to (x2, y2, z2), and in order to make it easier to see, 2 from the transmitter / receiver 30 of the second sonar portion 100B. One of the two exploration waves is omitted.

As shown in FIG. 18, two equations are obtained for the object by transmitting exploration waves having two directivities from the transmitter / receiver 30 to the object to be detected and measuring these reflected waves by two-frequency measurement. Be done. Specifically, the function of the distance D1 between the object and the first transmitter / receiver 30 and the function of the amplitude ratio R1 in the first sonar unit 100A are shown below by the two-frequency measurement by the first sonar unit 100A. Two formulas are obtained.

D1 = d (xx1, y-y1, z-z1) ... (1)
R1 = r (xx1, y-y1, z-z1) ... (2)
However, since there are three unknowns, x, y, and z, x, y, and z cannot be calculated by the above two equations alone, and the horizontal position of the object cannot be obtained. Therefore, in the present embodiment, the object is further added with the mathematical formulas (3) or (4) shown below by the two-frequency measurement by the second sonar unit 100B mounted at a position different from the first sonar unit 100A. Get the coordinates of the horizontal position of.

D2 = d (xx2, y-y2, z-z2) ... (3)
R2 = r (xx2, y-y2, z-z2) ... (4)
Equation (3) is a function of the distance D2 between the object and the second transmitter / receiver 30. Equation (4) is a function of the amplitude ratio R2 in the second sonar portion 100B.

Further, the coordinate calculation of the horizontal position of the object is calculated as (A) simultaneous equations, (B) in the d function, assuming that the measurements by the two sonar portions 100 are on the same plane, and Z = 0, D1, There are two methods of calculating x and y from D2, but either of them may be used. In the case of (A), since the calculation process is complicated, the calculation cost is high, but an accurate numerical value can be obtained. In the case of (B), since the calculation process is simplified by approximation, there is an advantage that the calculation cost is reduced and the processing efficiency is increased. When it is desired to reduce the number of parts as much as possible as in an in-vehicle application, the calculation method (B) that prioritizes processing efficiency is preferable.

[Operation processing example]
Next, an example of the operation processing in the object detection device 1 will be described with reference to FIGS. 20 and 21.

When the amplitude of the received signal generated by the receiving unit 50 becomes larger than the predetermined amplitude threshold value, the CPU executes the process of step S1. In step S1, the frequency separation unit 60 receives signals of two frequencies f _L, separated into frequency components corresponding to f _H, two separated frequencies f _L, the amplitude of the respective frequency components corresponding to f _H Extract A _L and A _H.

For example, with a predetermined time range as the analysis range, the frequency separation unit 60 extracts the amplitudes A _L and A _H from the portion of the received signal included in the analysis range. The analysis range is set with reference to the time when the amplitude of the received signal exceeds the amplitude threshold value, as shown in FIG. 21, for example. Further, the analysis range may be set with reference to the time when the amplitude of the received signal peaks or the rising start time of the received signal. Further, the analysis range may be a fixed time from the reference time, or may be a fixed time before and after the reference time. By setting the reference time of the analysis range to a predetermined time such as the rising start time of the received signal instead of the amplitude of the received signal, the determination accuracy can be further improved.

As shown in FIG. 21, for example, the frequency separation unit 60 extracts the amplitude A _L corresponding to the frequency f _L from the portion included in the analysis range of the amplitude waveform of the received signal passing through the BPF 61a by the amplitude generation unit 62a. To do. Further, the frequency separation unit 60 extracts the amplitude A _H corresponding to the frequency f _H from the portion included in the analysis range of the amplitude waveform of the received signal that has passed through the BPF 61b by the amplitude generation unit 62b.

In step S2, the amplitude ratio calculation unit 71 calculates the amplitude ratio Ar. Subsequently, in step S3, as described above, the horizontal position acquisition unit 72 uses the three mathematical formulas obtained by the two-frequency measurement in the first sonar unit 100A and the second sonar unit 100B to determine the horizontal position of the object. calculate.

In step S4, the signal determination unit 70 compares the amplitude ratio Ar with the reference value as described above, and determines whether or not the amplitude ratio Ar is within a predetermined range.

If the affirmative determination is made in step S4, the CPU advances the process to step S5. In step S5, the signal determination unit 70 sets a reference value for the amplitude ratio Ar for each horizontal position, for example, by using a data table corresponding to the horizontal position of the object. Then, the signal determination unit 70 determines whether or not the amplitude ratio is equal to or greater than the threshold value corresponding to the horizontal position.

In the case of an affirmative determination in step S5, the signal determination unit 70 transmits the reflected wave information to the control unit 40 and ends the reception process. As the reflected wave information, for example, a frequency pattern, TOF, peak value, etc. included in the reflected wave are transmitted. The control unit 40 performs a collision avoidance operation or the like according to the transmitted reflected wave information.

If a negative determination is made in step S4 or step S5, the reception process ends without executing step S6. That is, in a situation where it is determined that an object having a predetermined height or higher is not within the detection range based on the comparison result between the amplitude ratio Ar and the reference value or the comparison result between the amplitude of the received signal and the amplitude threshold value. The reception process ends without performing the collision avoidance operation or the like.

As described above, the object detection device 1 of the present embodiment transmits a search wave having two frequencies, extracts the amplitude for each frequency from the received signal, and calculates the extracted two amplitude ratios. Then, after the horizontal position acquisition unit 72 acquires the horizontal position of the object, the signal determination unit 70 sets a reference value (threshold) of the amplitude ratio according to the horizontal position, and compares the amplitude ratio with the reference value. By doing so, it is determined whether or not the object has a predetermined height or more. This makes it possible to distinguish between an object that may come into contact with the vehicle body and another object.

The amplitude of ultrasonic waves fluctuates due to the influence of air fluctuations due to wind, temperature unevenness, etc. while propagating in the air. This amount of amplitude variation acts in the same way for ultrasonic waves propagating along the same propagation path at the same time. On the other hand, the time from the start of transmission of two ultrasonic waves having different frequencies to the end of reception of reflected waves by these same objects is extremely short with respect to the rate of change of air fluctuations. Therefore, it is possible to treat the transmission of two ultrasonic waves having different frequencies as having substantially the same timing with respect to the rate of change of air fluctuation. This also applies to the reception of reflected waves. Therefore, the amount of amplitude fluctuation received by the reflected wave in the two frequency ultrasonic waves transmitted at substantially the same timing and reflected from the same object is almost the same. Therefore, the influence of air fluctuations can be canceled by taking the amplitude ratio of the reflected waves of the two frequencies. Therefore, in the method of comparing the two amplitudes corresponding to the two frequencies, the influence of the change in the amplitude level due to the air fluctuation or the like can be alleviated, and the determination accuracy of the object can be improved.

[Attenuation of linear distance and amplitude level]
Next, the relationship between the amplitude level of the reflected wave and the linear distance to the object will be described with reference to FIG.

In FIG. 22, “f _L ” indicates the amplitude at the frequency f _L , that is, the received voltage V _{r L.} Further, “f _H ” indicates the amplitude at the frequency f _H , that is, the received voltage V _{r H.}

As shown in FIG. 22, the amplitude of the reflected wave is attenuated as the distance from the object increases. Further, the amount of attenuation increases as the frequency increases. On the other hand, in the method using the amplitude ratio as in the present embodiment, the influence of the amount of attenuation generated by the distance can be reduced and the determination accuracy of the object can be improved.

The difference in the amount of attenuation generated depending on the distance generated by the difference in frequency can also be theoretically derived from the frequency. In the signal determination unit 70, the reference value used for the amplitude comparison is corrected by the theoretically obtained attenuation difference according to the linear distance to the object calculated from the TOF, so that the frequency difference is large and the attenuation is large. Even when the difference is large, the determination accuracy can be improved. Further, the signal determination unit 70 can also improve the determination accuracy by comparing the two amplitudes after correcting them according to the linear distance. The distance attenuation characteristic as shown in FIG. 22 can be obtained by actual measurement or a theoretical formula, and the reference value and the amount of amplitude correction can be set based on this distance attenuation characteristic.

[Frequency selection]
As shown in FIGS. 23 and 24, the larger the difference between the frequencies f _L and f _H , the larger the difference in directivity. Therefore, the difference in the amplitude level of the reflected wave becomes large, and whether the object is within the detection range. The accuracy of determining whether or not to use is improved. However, when the frequencies f _L and f _H deviate from the resonance band of the transmitter / receiver 30, the amplitude and reception sensitivity of the exploration wave decrease, and the long-distance detection performance deteriorates. Therefore, in order to improve the determination accuracy while maintaining the detection performance, it is desirable to set one of these two frequencies higher than the resonance frequency and the other lower than the resonance frequency. Furthermore, it is more desirable to select the upper limit value and the lower limit value of the resonance band of the transceiver 30 as f _H and f _L , respectively.

For example, when the resonance frequency of the transmitter / receiver 30 is f ₀ , f ₀ is the center frequency, and the range of the center frequency ± 3% is the resonance band, the center frequency + 3% is f _H and the center frequency is -3%. It is desirable to set f _L.

Further, in the case of intermittently transmitting the exploration wave of frequency f _{H and} the exploration wave of frequency f _L as in the present embodiment, if the distance between the two exploration waves is long, the amplitude A _H due to air fluctuation or the like, the difference is likely to occur in the amount of fluctuation of the a _L. Therefore, it is desirable to shorten the distance between the two exploration waves.

In addition, the long-distance detection performance is determined by the smaller amplitude of the two frequency exploration waves as a bottleneck. Therefore, it is desirable to set two frequencies so that the amplitudes of the reflected waves from the object in front of the transmitter / receiver 30 are equal at the frequencies f _L and f _H as shown in FIG.

For example, in front of the transmitter / receiver 30, the amplitude levels of the exploration waves corresponding to the frequencies f _L and f _H are equal, or the amplitude levels of the reflected waves from the object located in front of the transceiver 30 are equal. It is desirable to generate a drive signal as described above. It should be noted that the equal amplitude level here includes not only that the amplitude levels are completely equal but also that the amplitude levels are substantially equal.

If the amplitude level of the reflected wave from an object located in front of Sojushinko 30 are different, for example, the amplitude ratio as _{AR = 20log (A H / A} L), when the AR ≠ 0 is the amplitude ratio AR The amplitude ratio of the measurement result may be corrected based on the above. Alternatively, the reference value used for determining the amplitude ratio may be offset by the amplitude ratio AR.

Further, since the ultrasonic waves having a high frequency f _H have a larger distance attenuation than the ultrasonic waves having a low frequency f _L , in the case of long-distance detection, the amplitude of the exploration wave having a frequency f _H increases as shown in FIG. The frequencies f _L and f _H may be selected so as to be larger than the amplitude of the exploration wave at the frequency f _L.

Further, when the performance of determining the height of the object is emphasized, it is desirable to select the frequencies f _L and f _H so that the difference in directivity is maximized. However, if the frequencies f _L and f _H deviate from the band of the transmitter / receiver 30, the long-distance detection performance deteriorates. Therefore, in this case as well, the frequencies f _L and f _H should be selected so as to be included in the band of the transmitter / receiver 30. Is desirable.

According to the present embodiment, the object detection device 1 performs two-frequency measurement by two sonar units 100 using two exploration waves having different directivities due to different frequencies, and obtains the horizontal position of the object while acquiring the object. The amplitude ratio of two reflected waves with different directivity is calculated from. Further, by performing detection and determination of an object based on the amplitude of the received signal of the reflected wave corresponding to a plurality of frequencies, it is possible to mitigate the influence of the change in the amplitude level due to air fluctuation or the like. Then, the object detection device 1 changes the reference value of this amplitude ratio according to the horizontal position of the object, and then performs the detection determination of the object, so that the detection accuracy of the height of the object in the horizontal direction is higher than before. It has a high composition.

(Second Embodiment)
The object detection device 1 of the second embodiment will be described with reference to FIG. 27.

As shown in FIG. 27, the object detection device 1 of the present embodiment has only one sonar unit 100 including a transmission unit 10, a signal generation unit 20, a transmitter / receiver 30, a reception unit 50, and a frequency separation unit 60. It is configured to have. Then, in the present embodiment, the horizontal position acquisition unit 72 acquires the horizontal position information of the object with respect to the transmission unit 10 based on the reflected wave received by the reception unit 50 before and after the movement of the vehicle on which the object detection device 1 is mounted. It is configured to be. The object detection device 1 of the present embodiment is different from the first embodiment in the above points. In this embodiment, this difference will be mainly described.

In the present embodiment, the sonar unit 100 transmits two types of exploration waves having different directivities from the transmitter / receiver 30 before and after the movement of the vehicle on which the object detection device 1 is mounted, and then receives the reflected waves. That is, in the present embodiment, the position of the sonar portion 100 before the movement of the vehicle corresponds to the "first position", and the position of the sonar portion 100 after the movement of the vehicle corresponds to the "second position". In other words, the second position can be said to be a position generated by the movement of a moving body such as a vehicle.

In the present embodiment, the horizontal position acquisition unit 72 is, for example, the horizontal position acquisition unit 72 based on the distance to the object at the first position and the distance to the object at the second position, and the xy coordinates of the object by three-sided measurement. (That is, the plane coordinates) may be calculated and the horizontal position may be acquired. In this case, the horizontal position acquisition unit 72 calculates the plane coordinates with the z coordinate as zero, assuming that the distance measurement distances at the first position and the second position are the same plane for simplification of the calculation.

As a result, the horizontal position acquisition unit 72 can acquire the horizontal position of the object to be detected even if it has only one sonar unit 100.

The moving position of the vehicle can be acquired based on, for example, information such as a steering angle obtained by a steering angle sensor, a vehicle speed obtained by a vehicle speed sensor, and an angular velocity obtained by a gyro sensor, but is limited to this. is not.

According to the present embodiment, two-frequency measurement is performed before and after the movement of the moving body on which the object detection device 1 is mounted, and the object is based on the calculated amplitude ratio of the two types of reflected waves and the horizontal position of the object. By making the detection determination, the same effect as that of the first embodiment can be obtained. Further, since it is sufficient that the sonar portion 100 has one sonar portion 100, the number of parts is reduced and the manufacturing cost can be reduced.

(Third Embodiment)
The object detection device 1 of the third embodiment will be described with reference to FIG. 28.

As shown in FIG. 28, the object detection device 1 of the present embodiment is configured to have only one sonar unit 100, as in the second embodiment. Then, the sonar unit 100 further includes a directivity switching unit 80 in the present embodiment. Further, in the present embodiment, the horizontal position acquisition unit 72 calculates the horizontal position of the object based on the two-frequency measurement before and after the position change of the transmitter / receiver 30 by the directivity switching unit 80. The object detection device 1 of the present embodiment is different from the first embodiment in the above points. In this embodiment, this difference will be mainly described.

In the present embodiment, the sonar unit 100 has a configuration in which the transmission direction of the exploration wave can be changed by the directivity switching unit 80. The sonar unit 100 is set to the first position or the second position by the directivity switching unit 80, and the directivity is switched. In other words, it can be said that the second position is generated by the directivity switching unit 80 in the present embodiment.

The horizontal position acquisition unit 72 acquires the horizontal position of the object by two-frequency measurement at each of the first position and the second position using one sonar unit 100.

The directivity switching unit 80 is, for example, a driving unit for changing the direction of the transmitter / receiver 30. In this case, the sonar unit 100 may be referred to as a "swinging sonar".

Further, the directivity switching unit 80 may be a switching unit for switching the transmission unit for transmitting the exploration wave, for example, when the sonar unit 100 is configured to include a plurality of transmission units 10. In this case, the sonar unit 100 may be referred to as a "sonar array."

In any case, the transmission direction of the exploration wave can be switched by operating the directivity switching unit 80.

According to this embodiment, the same effect as that of the first embodiment can be obtained. Further, as in the second embodiment, the number of parts is reduced, and the effect of reducing the manufacturing cost is expected.

(Fourth Embodiment)
The object detection device 1 of the fourth embodiment will be described with reference to FIG. 29.

Similar to the second embodiment, the object detection device 1 of the present embodiment is configured to have only one sonar unit 100, and further includes an external information acquisition unit 90 for acquiring external information of the moving body. Then, the horizontal position acquisition unit 72 acquires the horizontal position of the object from the external information acquisition unit 90. The object detection device 1 of the present embodiment differs from the first embodiment in these points. In this embodiment, this difference will be mainly described.

The external information acquisition unit 90 is an arbitrary sensor that transmits and receives a second exploration wave different from ultrasonic waves, such as a camera that photographs the outside of the vehicle and LiDAR (abbreviation of Light Detection and Ranging). To. The external information acquisition unit 90 acquires information in a predetermined region including at least a predetermined range in the transmission direction of the exploration wave by the sonar unit 100 by imaging or transmitting / receiving the second exploration wave. The external information acquisition unit 90 may be configured to calculate the horizontal position of the object by a known method such as three-sided survey.

The external information acquisition unit 90 may be configured to output a signal obtained by imaging or the like to the horizontal position acquisition unit 72. In this case, the horizontal position acquisition unit 72 is obtained from the external information acquisition unit 90. The horizontal position of the object is calculated based on the signal.

The same effect as that of the first embodiment can be obtained by this embodiment as well.

(Other embodiments)
Although the present invention has been described in accordance with Examples, it is understood that the present invention is not limited to the Examples and structures. The present invention also includes various modifications and modifications within a uniform range. In addition, various combinations and forms, as well as other combinations and forms including only one element thereof, more or less, are also within the scope and ideology of the present invention.

(1) For example, in each of the above embodiments, an example has been described in which the sonar unit 100 includes a transmitter / receiver 30 in which the transmitter of the transmitter 10 and the receiver of the receiver 50 are integrated. However, as shown in FIG. 30, the sonar unit 100 has a transmitter 31 and a receiver 32 instead of the transmitter / receiver 30, and the transmitter 10 is composed of the transmitter circuit 11 and the transmitter 31 to receive. The unit 50 may be composed of a receiving circuit 51 and a receiver 32.

(2) The control unit 40 is not limited to a well-known microcomputer equipped with a CPU, ROM, RAM, I / O, and the like. For example, the control unit 40 may be an ASIC (abbreviation of APPLICATION SPECIFIC INTEGRATED CIRCUIT) such as a digital circuit configured to enable the above operation, for example, a gate array. The same applies to the signal determination unit 70 and the like.

1 Object detection device 10 Transmission unit 20 Signal generation unit 50 Reception unit 70 Judgment unit 72 Horizontal position acquisition unit 80 Directivity switching unit 90 External information acquisition unit 100 Sonar unit

Claims (8)

An object detection device (1) mounted on a moving body to detect an object.
A signal generator (20) that generates a drive signal,
A transmitter (10) that transmits ultrasonic waves as exploration waves in response to the input drive signal, and
A receiver (50) that receives ultrasonic waves and generates a reception signal,
A horizontal position acquisition unit (72) that acquires the position of the object in the horizontal direction with respect to the transmission unit, and
A signal determination unit (70) for detecting and determining the object based on the received signal and the position of the object is provided.
The receiving unit receives at least two reflected waves of the exploration wave having different directivity, and receives the reflected wave.
The signal determination unit calculates the height of the object based on the received signal and the position of the object, and determines that the object exists when the height is equal to or higher than a predetermined threshold value. The drive signal has at least two frequencies
The signal determination unit extracts at least two amplitudes corresponding to the at least two frequencies from the received signal, calculates the amplitude ratio or difference of the at least two frequencies, and then calculates the amplitude ratio or difference and the object. The object detection device according to claim 1, wherein the height of the object is calculated based on the position, and it is determined that the object exists when the height is equal to or higher than a predetermined threshold value. The horizontal position acquisition unit is obtained by transmitting and receiving the exploration wave at a first position and a second position different from the first position by a sonar unit (100) having the transmitting unit and the receiving unit. The object detection device according to claim 1 or 2, wherein the position of the object is acquired based on the received signal. Equipped with the two sonar sections
The sonar portion arranged at the first position is referred to as a first sonar portion (100A), and the sonar portion arranged at the second position is designated as a second sonar portion (100B).
The object according to claim 3, wherein the horizontal position acquisition unit acquires the position of the object based on the received signal obtained by transmitting and receiving the exploration wave by the first sonar unit and the second sonar unit. Detection device. With only one sonar section,
The horizontal position acquisition unit acquires the position of the object based on the received signal obtained by transmitting and receiving the exploration wave by each of the sonar unit at the first position and the sonar unit at the second position. And
The object detection device according to claim 3, wherein the second position is generated by the movement of the moving body. With only one sonar section,
The sonar unit includes a directivity switching unit (80) for switching the transmission direction of the exploration wave.
The object detection device according to claim 3, wherein the second position is generated by the directivity switching unit. Further equipped with an external information acquisition unit (90)
The horizontal position acquisition unit acquires the position of the object based on the information obtained by the external information acquisition unit.
The object detection device according to claim 1 or 2, wherein the external information acquisition unit is a camera that images the outside of the moving body. Further equipped with an external information acquisition unit (90)
The horizontal position acquisition unit acquires the position of the object based on the information obtained by the external information acquisition unit.
The object detection device according to claim 1 or 2, wherein the external information acquisition unit is a sensor that transmits / receives a second exploration wave different from ultrasonic waves to the outside of the moving body.

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