JP2007121045A - Ultrasonic object detector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To detect a distance to an object to be measured and the direction of the object to be measured at low costs and with high resolution. <P>SOLUTION: First, a single transmitter 2 transmits ultrasonic waves in one-cycle waveform. Then, the ultrasonic waves are reflected by the object to be measured. Then, a reference wave receiving element 30 at a wave reception section 3 and respective wave receiving elements 31a-34d receive ultrasonic waves reflected by the object to be measured. The reference wave receiving element 30 is arranged at the center of a square as the wave reception section 3, and the plurality of wave receiving elements 31a-34d are arranged on the side of the square at a fixed interval so that the distance to the reference wave receiving element 30 becomes longer than that to the adjacent wave receiving elements 31a-34d. In this case, a detection section simultaneously detects the distance to the object to be measured and the direction of the object to be measured by adding delay corresponding to each direction and obtaining delay addition strength. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an ultrasonic object detection device used for detecting a distance to a measurement object and a direction of the measurement object.

  Conventionally, various ultrasonic object detection devices of this type have been proposed and developed. For example, Patent Document 1 discloses a three-dimensional sensor (ultrasonic object detection device) using an ultrasonic array having a receiving unit in which a plurality of elements (receiving elements) are arranged in a one-dimensional array or a two-dimensional array. ) Is disclosed. The three-dimensional sensor of Patent Document 1 emits a directivity ultrasonic beam, receives a reflected wave from a detection target (measured object), and detects a distance from the detection target.

Further, as shown in FIG. 14, the conventional ultrasonic object detection apparatus includes a wave receiving unit 8 in which a plurality of wave receiving elements 80 are arranged in a T shape. As another example, a receiving unit 8a (see FIG. 15) in which a plurality of receiving elements 80... Are arranged in a vertical and horizontal cross, and a receiving unit 8b (see FIG. 15) arranged in an oblique cross in addition to vertical and horizontal. 16), or receiving portions 8c (see FIG. 17) arranged in a 3 × 3 matrix.
Japanese Examined Patent Publication No. 6-27803 (pages 2 to 6 and FIG. 5)

  However, the conventional ultrasonic object detection device described above receives ultrasonic waves reflected by the object to be measured by the wave receiving unit as in Patent Document 1 or the wave receiving units 8 and 8a to 8c as shown in FIGS. Since the wave is received, there is a problem that an error becomes large when detecting the direction of the object to be measured. As shown in FIG. 18, the above problem is solved even when a receiving unit 8d in which a plurality of receiving elements 80... Are arranged in a 5 × 5 matrix is used. As the number increased, a new problem of high costs occurred.

  The present invention has been made in view of the above points, and an object thereof is an ultrasonic wave capable of detecting the distance to the object to be measured and the direction of the object to be measured with low cost and high resolution. The object is to provide an object detection device.

  According to the first aspect of the present invention, the transmitting means for transmitting the ultrasonic wave having a predetermined frequency to the detection area, and each receiving the ultrasonic wave reflected by the measurement object in the detection area. A plurality of receiving elements for converting into received signals, and the time to be measured based on the time required for the ultrasonic waves to be received by the plurality of receiving elements after being transmitted by the transmitting means. Detecting a distance to an object, and detecting a direction of the object to be measured based on a time difference of the received signals from each of the plurality of receiving elements, and transmitting by the transmitting means The ultrasonic wave having a waveform of one period, one receiving element of the plurality of receiving elements is arranged at the center of a polygon or a circle, and each of the other receiving elements is adjacent to another The distance to the one receiving element from the distance to the receiving element Characterized in that it is arranged on a side of the polygon or the circle to be longer.

  With this configuration, it is possible to detect the distance to the object to be measured and the direction of the object to be measured with low cost and high resolution.

  The invention according to claim 2 is the invention according to claim 1, wherein the polygon is a regular polygon. With this configuration, it is possible to improve the resolution for detecting the position of the object to be measured.

  The invention according to claim 3 is the invention according to claim 2, wherein the regular polygon is a square. With this configuration, it is possible to improve the resolution for detecting the position of the object to be measured.

  According to the present invention, the distance to the object to be measured and the direction of the object to be measured can be detected at low cost and with high resolution.

(Embodiment 1)
A first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a front view of the ultrasonic object detection apparatus according to the first embodiment. FIG. 2 is a diagram illustrating a relationship between the ultrasonic object detection device according to the first embodiment and an object to be measured. FIG. 3 is a diagram illustrating reception of the ultrasonic object detection device according to the first embodiment. FIG. 4 is a diagram for explaining the operation when the object to be measured is in front of the ultrasonic object detection apparatus according to the first embodiment. FIG. 5 is a diagram for explaining the operation when the object to be measured is at the angle θ in the ultrasonic object detection apparatus according to the first embodiment. FIG. 6 is a diagram illustrating a case where the distance between the reference receiving element and other receiving elements is different in the ultrasonic object detection device of the first embodiment.

  First, the basic configuration of the first embodiment will be described. As shown in FIG. 1, the ultrasonic object detection device (ultrasonic three-dimensional sensor) of Embodiment 1 includes a case 1, a transmitter 2, and a wave receiver 3, and a detector 4 ( 4). As shown in FIG. 2, the ultrasonic object detection apparatus detects the distance to the measurement object B in the detection region A and the direction (three-dimensional coordinates) of the measurement object B.

  As shown in FIG. 1, the case 1 has a thin front surface formed in a substantially rectangular shape. The case 1 includes a single transmitter 2 and a wave receiving unit 3 arranged on the front surface 10 and houses a detection unit 4 (see FIG. 4).

  As shown in FIG. 2, the wave transmitter 2 transmits ultrasonic waves having a waveform of only one period to the detection region A. The ultrasonic wave is a waveform having a predetermined frequency such as 40 kHz, for example, and the wavelength is λ.

  As shown in FIG. 1, the wave receiving unit 3 includes a reference wave receiving element 30 and a plurality of wave receiving elements 31 a to 34 d. The reference wave receiving element 30 is arranged at the center of the square, and is a wave receiving element that serves as a reference when specifying the distance to the measured object B (see FIG. 2). On the other hand, each of the plurality of wave receiving elements 31a to 34d is arranged at regular intervals on the square side so that the distance from the reference wave receiving element 30 is longer than the distance from the adjacent wave receiving elements 31a to 34d. Has been. Specifically, the distance between the reference receiving element 30 and the receiving elements 31a to 34d is λ or more, and the distance between the adjacent receiving elements 31a to 34d is λ / 2. Each of the reference wave receiving element 30 and the wave receiving elements 31a to 34d receives the ultrasonic wave reflected by the measured object B and converts it into a wave receiving signal which is an electric signal. Furthermore, each of the reference receiving element 30 and the receiving elements 31a to 34d outputs the received signal to the detection unit 4 (see FIG. 4). By arranging the reference receiving element 30 and the receiving elements 31a to 34d as described above, it is possible to make an erroneous measurement point difficult to appear.

  The detection unit 4 (see FIG. 4) is measured based on the time required from when the ultrasonic wave is transmitted by the transmitter 2 until it is received by the reference receiving element 30 and the receiving elements 31a to 34d. The distance to the object B (see FIG. 2) is detected. Further, the detection unit 4 detects the direction of the measurement object B based on the time difference between the reception signal of the reference reception element 30 and the reception signals of the reception elements 31a to 34d. Here, as a specific example, a method for detecting the direction of the measurement object B from the received signals of the reference receiving element 30 and the receiving element 31d will be described with reference to FIG. The position of the reference wave receiving element 30 is the origin (0, 0), and the position of the wave receiving element 31d is (dx, dy). The wave receiving element 31d generates a path difference from the reference wave receiving element 30 with respect to the direction (θ, ψ) of the object B to be measured from which the ultrasonic waves are reflected. The delay time (time difference) Δt is uniquely determined by the path difference. Thereby, when the arrangement of the reference receiving element 30 and the receiving elements 31a to 34d is determined, a delay time table for the reference receiving element 30 and the receiving elements 31a to 34d is created. That is, in the case of direction (θ1, ψ1), direction (θ1, ψ2), in the case of direction (θ1, ψ3), in the case of direction (θ2, ψ2), and in the horizontal direction (vertical direction in FIG. ) × delay times Δt corresponding to the number corresponding to the resolution in the vertical direction (horizontal direction) (in the first embodiment, 19 × 19 at 5 ° intervals and −45 to + 45 °) are obtained.

  When dxdy ≠ 0, the delay time Δt is calculated by Equation 1 and Equation 2. However, A and B in Equation 2 are shown in Equation 3 and Equation 4. Note that the speed of sound is c.

  On the other hand, when dx = 0, the delay time Δt is calculated by Equation 5.

  When dy = 0, the delay time Δt is calculated by Equation 6.

  When each received signal of the reference receiving element 30 and the receiving elements 31a to 34d receives an ultrasonic wave, the detection unit 4 first receives the received signals from the reference receiving element 30 and the receiving elements 31a to 34d. input. Subsequently, based on the delay time table, the received signals of the receiving elements 31a to 34d are shifted by the delay time Δt when it is assumed that the measured object B (see FIG. 2) exists in the direction (θ1, ψ1). And adding to the received signal of the reference receiving element 30 to obtain the delayed added strength. Similarly, in the case of direction (θ1, ψ2), in the case of direction (θ1, ψ3),... Finally, it is determined from the distribution of the delayed addition intensity that the measured object B exists in the direction (θ, ψ) in which the intensity is strongest.

  Next, the operation of the ultrasonic object detection apparatus when the measured object B (see FIG. 2) is directly in front of the ultrasonic object detection apparatus according to the first embodiment will be described with reference to FIG. 4B shows the delay addition intensity when the delay addition corresponding to −45 ° is performed, and FIG. 4C shows the delay addition intensity when the delay addition corresponding to 0 ° is performed. FIG. 4D shows the delay addition intensity when the delay addition corresponding to 45 ° is performed. First, the transmitter 2 (see FIG. 2) transmits ultrasonic waves having a waveform of one cycle. Thereafter, the ultrasonic wave is reflected by the measurement object B. Subsequently, each of the reference wave receiving element 30 and the wave receiving elements 31a to 34d receives the ultrasonic waves reflected by the measured object B as shown in FIG. At this time, since the ultrasonic wave arrives from directly in front of the ultrasonic object detection device, the reference wave receiving element 30 and all the wave receiving elements 31a to 34d receive the wave at the same timing. As a result, the delay addition intensity becomes maximum when delay addition corresponding to 0 ° is performed as shown in FIG. 4C, and the object to be measured is read by reading the time received by the reference receiving element 30. The distance to B is detected.

  In contrast, the operation of the ultrasonic object detection apparatus when the object to be measured B (see FIG. 2) is displaced from the front in front of the ultrasonic object detection apparatus according to the first embodiment and is at the angle θ will be described with reference to FIG. . 5B shows the delay addition intensity when the delay addition corresponding to −45 ° is performed, and FIG. 5C shows the delay addition intensity when the delay addition corresponding to 0 ° is performed. FIG. 5D shows the delay addition intensity when the delay addition corresponding to the angle θ is performed. First, the ultrasonic wave is transmitted from the wave transmitter 2 (see FIG. 2) and reflected by the measured object B, as in the case where the measured object B is directly in front. Thereafter, each of the reference wave receiving element 30 and the wave receiving elements 31a to 34d receives the ultrasonic wave reflected by the measured object B as shown in FIG. At this time, as shown in FIGS. 5B to 5D, when the detection unit 4 performs delay addition, the delay addition intensity becomes maximum when the delay addition corresponding to the angle θ is performed. Thereby, the distance to the measured object B and the direction of the measured object B are detected simultaneously.

  Next, the delay addition intensity with respect to the distance between the reference receiving element 30 and the receiving elements 31a to 34d will be described with reference to FIG. 6 shows a procedure of delay addition when the reference receiving element 30 and the receiving elements 31a to 34d are arranged in only one axial direction (for example, the up and down direction and the left and right direction in FIG. 1). 6A and 6B are compared, the longer the distance between the reference wave receiving element 30 and the wave receiving elements 31a to 34d, the larger the intensity change with respect to the angle change. Thereby, the direction resolution can be increased.

  If the ultrasonic wave is a continuous waveform, if the distance between the reference receiving element 30 and the receiving elements 31a to 34d exceeds λ / 2, the value to be added overlaps with the next waveform. Although the distance between the element 30 and the wave receiving elements 31a to 34d needs to be within λ / 2, in the first embodiment, since the ultrasonic wave has a waveform of one cycle, the reference wave receiving element 30 and the wave receiving element 31a. There is no problem even if the distance between ˜34d is increased.

  Next, FIG. 7 shows an intensity distribution image when the object to be measured B (see FIG. 2) is in the direction (0, 0) in front of the object. The horizontal axis is the horizontal angle (left-right angle in FIG. 1), and the vertical axis is the vertical angle (up-down direction angle in FIG. 1). In FIG. 7, the intensity is greatest when both the horizontal angle and the vertical angle are 0 °. On the other hand, FIG. 8 shows an intensity distribution image when the measured object B is in a direction (−45, −45) inclined by 45 ° in both the horizontal angle and the vertical angle. The horizontal axis is the horizontal angle, and the vertical axis is the vertical angle. In FIG. 8, there is a maximum peak when the horizontal angle and the vertical angle are both −45 °, and the intensity is the highest. It should be noted that the second largest peak appears around 10 ° in both the horizontal angle and the vertical angle.

  Here, the peak half-value area when the object to be measured B (see FIG. 2) is in the direction (0, 0) in front of the receiving section 3 (see FIG. 1) of the first embodiment and the conventional receiving section. And the peak ratio when the measured object B is in a direction (−45, −45) inclined by 45 ° in both the horizontal angle and the vertical angle. The measurement results are shown in Embodiment 1 in FIG. The peak half-value area is an area of a portion having an intensity of 50% or more of the maximum peak centering on the maximum peak in the intensity distribution image (see FIG. 7). The smaller the peak half-value area, the better, and when it is 75 or less, the receiving part is better. This is because when the peak half-value area increases, when noise is superimposed at a position different from the position of the maximum peak, the intensity at the position where the noise is superimposed becomes larger than the maximum peak, and the direction of the object B to be measured is changed. This is because they are detected erroneously. The peak ratio is the intensity ratio of the second largest peak with respect to the maximum peak in the intensity distribution image (see FIG. 8). The smaller the peak ratio, the better. When the peak ratio is 0.15 or less, the receiving part is better. This is because, when the peak ratio increases, when noise is superimposed at the position of the second largest peak, the intensity of the second largest peak becomes larger than the maximum peak due to the noise superposition, and the direction of the object B to be measured is changed. This is because they are detected erroneously. In FIG. 9, as a conventional receiving unit, Comparative Example 1 has a plurality of receiving elements arranged in a T shape (see FIG. 14), and Comparative Example 2 has a vertical and horizontal cross (see FIG. 15). Reference Example), Comparative Example 3 is arranged in a diagonal cross, Comparative Example 4 is arranged in a vertical and horizontal diagonal cross (see FIG. 16), and Comparative Example 5 is arranged in a 3 × 3 matrix (see FIG. 16). 17), Comparative Example 6 shows the measurement results when arranged in a 5 × 5 matrix (see FIG. 18).

  First, Embodiment 1 is compared with Comparative Example 5 (see FIG. 17). In Embodiment 1, the peak half-value area is reduced by about 79% and the peak ratio is reduced by about 39% compared to Comparative Example 5. Thereby, Embodiment 1 can improve the resolution which specifies the direction of the to-be-measured object B (refer FIG. 2) from the comparative example 5. FIG. Subsequently, Embodiment 1 and Comparative Example 6 (see FIG. 18) are compared. In the first embodiment, the number of receiving elements can be reduced from 25 to 17 as compared with Comparative Example 6, and the peak half-value area is reduced by about 32% as compared with Comparative Example 6. This is because the receiving element is arranged farther from the reference receiving element than the comparative example 6 in the first embodiment, and the amount of decrease in the delay addition per angle change is larger. That is, in the case of the first embodiment, the delay addition intensity in the direction corresponding to the periphery of the maximum intensity is reduced by removing the receiving element close to the reference receiving element from the comparative example 6. Furthermore, when comparing Embodiment 1 with Comparative Examples 1 to 4 (see FIGS. 14 to 16), Embodiment 1 is smaller in both peak half-value area and peak ratio than Comparative Examples 1 to 4.

  As described above, according to the first embodiment, by transmitting a waveform of one period from the transmitter 2, it is possible to make an erroneous measurement point difficult to appear, and the distance to the measured object B and the direction of the measured object B. Can be detected at low cost and with high resolution. This is particularly remarkable as compared with the case where the wave receiving elements are arranged in a T-type, cross, 3 × 3 matrix.

(Embodiment 2)
A second embodiment of the present invention will be described with reference to FIG. FIG. 10 is a front view of a wave receiving unit in the ultrasonic object detection apparatus according to the second embodiment.

  Similar to the ultrasonic object detection device (see FIG. 1) according to the first embodiment, the ultrasonic object detection device according to the second embodiment includes a case 1, a transmitter 2, and a detection unit 4 (see FIG. 4). However, there is a characteristic part described below that is not included in the ultrasonic object detection apparatus of the first embodiment.

  The ultrasonic object detection apparatus according to the second embodiment includes a wave receiving unit 5 as illustrated in FIG. 10 instead of the wave receiving unit 3 according to the first embodiment. The wave receiving unit 5 includes a reference wave receiving element 50 and a plurality of wave receiving elements 51a to 53d. The reference wave receiving element 50 is disposed at the center of an equilateral triangle. On the other hand, each of the plurality of receiving elements 51a to 53d is arranged at regular intervals on the sides of the equilateral triangle so that the distance to the reference receiving element 50 is longer than the distance to the adjacent receiving elements 51a to 53d. Has been. The wave receiving unit 5 is the same as the wave receiving unit 3 (see FIG. 1) of the first embodiment except for the points described above.

  Next, the peak half-value area when the object to be measured B (see FIG. 2) is in the direction (0, 0) in front of the wave receiving part 5 of the second embodiment and the conventional wave receiving part, and the object to be measured The peak ratio was measured when B was in the direction (−45, −45) inclined by 45 ° in both the horizontal angle and the vertical angle. The measurement results are shown in Embodiment 2 in FIG. First, Embodiment 2 is compared with Comparative Example 5 (see FIG. 17). In Embodiment 2, the peak half-value area is reduced by about 41% and the peak ratio is reduced by about 50% compared to Comparative Example 5. Thereby, Embodiment 2 can improve the resolution which specifies the direction of the to-be-measured object B (refer FIG. 2) from the comparative example 5. FIG. Subsequently, Embodiment 2 and Comparative Example 6 (see FIG. 18) are compared. In the second embodiment, although the peak half-value area is increased as compared with Comparative Example 6, the number of receiving elements can be reduced from 25 to 13 without increasing the peak ratio. Furthermore, when Embodiment 2 and Comparative Examples 1-4 (refer FIGS. 14-16) are compared, Embodiment 2 has a smaller peak ratio than Comparative Examples 1-4.

  As described above, according to the second embodiment, the distance to the measured object B and the direction of the measured object B are detected at a lower cost and with higher resolution than when the receiving elements are arranged in a 3 × 3 matrix. be able to. Further, the measurement resolution when the measured object B is inclined by 45 ° can be improved as compared with the case where the wave receiving elements are arranged in a T shape and a cross.

(Embodiment 3)
A third embodiment of the present invention will be described with reference to FIG. FIG. 11 is a front view of a wave receiving unit in the ultrasonic object detection apparatus according to the third embodiment.

  Similar to the ultrasonic object detection device (see FIG. 1) according to the first embodiment, the ultrasonic object detection device according to the third embodiment includes a case 1, a transmitter 2, and a detection unit 4 (see FIG. 4). However, there is a characteristic part described below that is not included in the ultrasonic object detection apparatus of the first embodiment.

  The ultrasonic object detection apparatus according to the third embodiment includes a wave receiving unit 6 as illustrated in FIG. 11 instead of the wave receiving unit 3 according to the first embodiment. The wave receiving unit 6 includes a reference wave receiving element 60 and a plurality of wave receiving elements 61a to 65c. The reference receiving element 60 is arranged at the center of a regular pentagon. On the other hand, each of the plurality of receiving elements 61a to 65c is arranged at regular intervals on a regular pentagonal side so that the distance to the reference receiving element 60 is longer than the distance to the adjacent receiving elements 61a to 65c. Has been. The wave receiving unit 6 is the same as the wave receiving unit 3 (see FIG. 1) of the first embodiment except for the points described above.

  Next, in the wave receiving unit 6 of Embodiment 3 and the conventional wave receiving unit, the peak half-value area when the measured object B (see FIG. 2) is in the frontal direction (0, 0), and the measured object The peak ratio was measured when B was in the direction (−45, −45) inclined by 45 ° in both the horizontal angle and the vertical angle. The measurement results are shown in Embodiment 3 in FIG. First, Embodiment 3 is compared with Comparative Example 5 (see FIG. 17). In Embodiment 3, the peak half-value area is reduced by about 67% and the peak ratio is reduced by about 50% compared to Comparative Example 5. Thereby, Embodiment 3 can improve the resolution which specifies the direction of the to-be-measured object B (refer FIG. 2) from the comparative example 5. FIG. Subsequently, Embodiment 3 and Comparative Example 6 (see FIG. 18) are compared. The third embodiment can reduce the number of receiving elements from 25 to 16 without increasing the peak half-value area and the peak ratio as compared with Comparative Example 6. Furthermore, when Embodiment 3 and Comparative Examples 1-4 (refer FIGS. 14-16) are compared, Embodiment 3 has both a peak half value area and a peak ratio smaller than Comparative Examples 1-4.

  As described above, according to the third embodiment, the distance to the measured object B and the direction of the measured object B can be reduced at a lower cost than when the receiving elements are arranged in a T-shaped, crossed, 3 × 3 matrix. It can be detected with high resolution. Further, the number of receiving elements can be reduced while obtaining the same characteristics as when receiving elements are arranged in a 5 × 5 matrix.

(Embodiment 4)
Embodiment 4 of the present invention will be described with reference to FIG. FIG. 12 is a front view of a wave receiving unit in the ultrasonic object detection apparatus according to the fourth embodiment.

  Similar to the ultrasonic object detection device (see FIG. 1) according to the first embodiment, the ultrasonic object detection device according to the fourth embodiment includes a case 1, a transmitter 2, and a detection unit 4 (see FIG. 4). However, there is a characteristic part described below that is not included in the ultrasonic object detection apparatus of the first embodiment.

  The ultrasonic object detection apparatus according to the fourth embodiment includes a wave receiving unit 7 as illustrated in FIG. 12 instead of the wave receiving unit 3 according to the first embodiment. The wave receiving unit 7 includes a reference wave receiving element 70 and 12 wave receiving elements 71a to 74c. The reference wave receiving element 70 is arranged at the center of a circle having a radius λ. Note that λ is the wavelength of the ultrasonic wave transmitted from the transmitter 2. On the other hand, each of the plurality of wave receiving elements 71a to 74c is arranged at regular intervals on the side of the circle so that the distance to the reference wave receiving element 70 is longer than the distance to the adjacent wave receiving elements 71a to 74c. ing. The wave receiving unit 7 is the same as the wave receiving unit 3 (see FIG. 1) of the first embodiment except for the points described above.

  As described above, even in the fourth embodiment, the distance to the measured object B and the direction of the measured object B can be detected with low cost and high resolution.

(Embodiment 5)
Embodiment 5 of the present invention will be described with reference to FIG. FIG. 13 is a front view of a wave receiving unit in the ultrasonic object detection apparatus according to the fifth embodiment.

  Similar to the ultrasonic object detection device (see FIG. 1) according to the fourth embodiment, the ultrasonic object detection device according to the fifth embodiment includes a case 1, a transmitter 2, and a detection unit 4 (see FIG. 4). However, there is a characteristic portion described below that is not included in the ultrasonic object detection apparatus of the fourth embodiment.

  The ultrasonic object detection apparatus according to the fifth embodiment includes a wave receiving unit 7a as illustrated in FIG. 13 instead of the wave receiving unit 7 according to the fourth embodiment. The wave receiving unit 7a includes a reference wave receiving element 70 and 16 wave receiving elements 71a to 74d. The reference receiving element 70 is disposed at the center of the circle. On the other hand, each of the plurality of receiving elements 71a to 74d is arranged on the side of the circle at regular intervals so that the distance to the reference receiving element 70 is longer than the distance to the adjacent receiving elements 71a to 74d. ing. The wave receiving unit 7a is the same as the wave receiving unit 7 of the fourth embodiment (see FIG. 12) in points other than the above.

  Next, in the wave receiving unit 7a of the fifth embodiment and the conventional wave receiving unit, the peak half-value area when the measured object B (see FIG. 2) is in the frontal direction (0, 0), and the measured object The peak ratio was measured when B was in the direction (−45, −45) inclined by 45 ° in both the horizontal angle and the vertical angle. The measurement results are shown in Embodiment 5 in FIG. First, Embodiment 5 is compared with Comparative Example 5 (see FIG. 17). In the fifth embodiment, the peak half-value area is reduced by about 68% and the peak ratio is reduced by about 44% compared to the comparative example 5. Thereby, Embodiment 5 can improve the resolution for specifying the direction of the object B to be measured as compared with Comparative Example 5. Subsequently, Embodiment 5 and Comparative Example 6 (see FIG. 18) are compared. In the fifth embodiment, the number of wave receiving elements can be reduced from 25 to 17 without substantially increasing the peak half-value area and the peak ratio as compared with Comparative Example 6. Furthermore, when Embodiment 5 is compared with Comparative Example 4 (see FIG. 16), Embodiment 5 has both the number of receiving elements equivalent to that of Comparative Example 4, but both the peak half-value area and the peak ratio are reduced. Comparing Embodiment 5 and Comparative Examples 1 to 3 (see FIGS. 14 and 15), Embodiment 5 has both a peak half-value area and a peak ratio smaller than those of Comparative Examples 1 to 3.

  As described above, according to the fifth embodiment, the distance to the measured object B and the direction of the measured object B can be reduced at a lower cost than when the receiving elements are arranged in a T-shaped, cross, 3 × 3 matrix. It can be detected with high resolution. Further, the number of receiving elements can be reduced while obtaining substantially the same characteristics as when receiving elements are arranged in a 5 × 5 matrix.

(Embodiment 6)
Embodiment 6 of the present invention will be described.

  Similar to the ultrasonic object detection device (see FIG. 1) according to the fourth embodiment, the ultrasonic object detection device according to the sixth embodiment includes a case 1, a transmitter 2, and a detection unit 4 (see FIG. 4). However, there is a characteristic portion described below that is not included in the ultrasonic object detection apparatus of the fourth embodiment.

  The ultrasonic object detection apparatus according to the sixth embodiment includes a wave receiving unit having a radius of 1.25λ instead of the wave receiving unit 7 according to the fourth embodiment. Note that λ is the wavelength of the ultrasonic wave transmitted from the transmitter 2. Further, the receiving unit of the sixth embodiment is the same as the receiving unit 7 of the fourth embodiment (see FIG. 12) except for the points described above.

  Next, the peak half-value area when the object to be measured B (see FIG. 2) is in the direction (0, 0) in front of the wave receiving part of the sixth embodiment and the conventional wave receiving part, and the object to be measured B Was measured in the direction (−45, −45) inclined 45 ° both in the horizontal angle and in the vertical angle. The measurement results are shown in Embodiment 6 of FIG. First, Embodiment 6 is compared with Comparative Example 5 (see FIG. 17). In Embodiment 6, the peak ratio is larger than that of Comparative Example 5, but the peak half-value area is reduced by about 82%. Subsequently, Embodiment 6 and Comparative Example 6 (see FIG. 18) are compared. In the sixth embodiment, although the peak ratio is increased as compared with Comparative Example 6, the peak half-value area is reduced by about 43%, and the number of receiving elements can be reduced from 25 to 13. Furthermore, when Embodiment 6 is compared with Comparative Example 4 (see FIG. 16), the peak half-value area of Embodiment 6 is about 53% less than that of Comparative Example 4. Comparing Embodiment 6 and Comparative Examples 1 to 3 (see FIGS. 14 and 15), Embodiment 6 is smaller in both peak half-value area and peak ratio than Comparative Examples 1 to 3.

  As described above, according to the sixth embodiment, the distance to the object to be measured B and the direction of the object to be measured B can be reduced at a lower cost and with higher resolution than when the receiving elements are arranged in a T shape, vertical and horizontal crosses, and oblique crosses. Can be detected.

(Embodiment 7)
Embodiment 7 of the present invention will be described.

  Similar to the ultrasonic object detection device (see FIG. 1) according to the fourth embodiment, the ultrasonic object detection device according to the seventh embodiment includes a case 1, a transmitter 2, and a detection unit 4 (see FIG. 4). However, there is a characteristic portion described below that is not included in the ultrasonic object detection apparatus of the fourth embodiment.

  The ultrasonic object detection device according to the seventh embodiment includes a wave receiving unit having a radius of 1.5λ instead of the wave receiving unit 7 according to the fourth embodiment. Note that λ is the wavelength of the ultrasonic wave transmitted from the transmitter 2. Further, the receiving unit of the seventh embodiment is the same as the receiving unit 7 of the fourth embodiment (see FIG. 12) in points other than the above.

  Next, the peak half-value area when the object to be measured B (see FIG. 2) is in the direction (0, 0) in front of the receiving part of the seventh embodiment and the conventional receiving part, and the object to be measured B Was measured in the direction (−45, −45) inclined 45 ° both in the horizontal angle and in the vertical angle. The measurement results are shown in Embodiment 7 of FIG. First, Embodiment 7 and Comparative Example 5 are compared. In Embodiment 7, the peak ratio is larger than that of Comparative Example 5, but the peak half-value area is reduced by about 89%. Subsequently, Embodiment 7 and Comparative Example 6 are compared. In Embodiment 7, although the peak ratio is larger than that of Comparative Example 6, the peak half-value area is reduced by about 65%, and the number of receiving elements can be reduced from 25 to 13. Further, when the embodiment 7 and the comparative example 4 are compared, the peak half-value area of the seventh embodiment is reduced by about 71% while the peak ratio is substantially the same as that of the comparative example 4. When Embodiment 7 and Comparative Examples 1 to 3 are compared, Embodiment 5 is smaller in both peak half-value area and peak ratio than Comparative Examples 1 to 3.

  As described above, according to the seventh embodiment, the distance to the object to be measured B and the direction of the object to be measured B can be detected at a lower cost and with higher resolution than when the receiving elements are T-shaped and arranged in a cross. it can. In addition, the characteristic balance between the case in which the measured object B is in the direction directly in front and the direction in which it is inclined by 45 ° is better than that in the case where the measurement object B is arranged in a matrix.

It is a front view of the ultrasonic object detection apparatus of Embodiment 1 by the present invention. It is a figure which shows the relationship between an ultrasonic object detection apparatus same as the above, and a to-be-measured object. It is a figure explaining the wave reception of an ultrasonic object detection apparatus same as the above. In the ultrasonic object detection apparatus described above, (a) is a diagram for explaining the operation when the object to be measured is directly in front, (b) is the delay addition intensity when the delay addition corresponding to −45 ° is performed, ( c) is the delay addition intensity when the delay addition corresponding to 0 ° is performed, and (d) is the delay addition intensity when the delay addition corresponding to 45 ° is performed. In the ultrasonic object detection apparatus as described above, (a) is a diagram for explaining the operation when the object to be measured is at the angle θ, (b) is the delay addition intensity when the delay addition corresponding to −45 ° is performed, (C) is the delay addition intensity when delay addition corresponding to 0 ° is performed, and (d) is the delay addition intensity when delay addition corresponding to the angle θ is performed. In the ultrasonic object detection apparatus as described above, (a) illustrates a case where the distance between the reference receiving element and another receiving element is short, and (b) illustrates the relationship between the reference receiving element and the other receiving element. It is a figure explaining the case where distance is long. In an ultrasonic object detection apparatus same as the above, it is a figure which shows an intensity distribution image in case a to-be-measured object exists in the front direction. FIG. 6 is a diagram showing an intensity distribution image when the object to be measured is in a direction inclined by 45 ° in both the horizontal angle and the vertical angle in the ultrasonic object detection apparatus same as above. In the ultrasonic object detection devices according to the first to third and fifth to seventh embodiments, the peak half-value area when the object to be measured is directly in front and the object to be measured are in a direction inclined by 45 ° in both the horizontal angle and the vertical angle. It is a figure which shows the peak ratio in a case. It is a front view of the wave receiving part in the ultrasonic object detection apparatus of Embodiment 2 by the present invention. It is a front view of the wave receiving part in the ultrasonic object detection apparatus of Embodiment 3 by the present invention. It is a front view of the wave receiving part in the ultrasonic object detection apparatus of Embodiment 4 by the present invention. It is a front view of the wave receiving part in the ultrasonic object detection apparatus of Embodiment 5 by the present invention. It is a front view of the wave receiving part in the conventional ultrasonic object detection apparatus. It is a front view of the wave-receiving part in the other ultrasonic object detection apparatus same as the above. It is a front view of the wave-receiving part in the other ultrasonic object detection apparatus same as the above. It is a front view of the wave-receiving part in the other ultrasonic object detection apparatus same as the above. It is a front view of the wave-receiving part in the other ultrasonic object detection apparatus same as the above.

Explanation of symbols

2 Transmitter 3 Receiver 30 Reference receiver 31a-34d Receiver

Claims (3)

Wave transmitting means for transmitting ultrasonic waves of a predetermined frequency to the detection region;
A plurality of receiving elements each receiving the ultrasonic wave reflected by the object to be measured in the detection region and converting it into a received signal;
The distance to the object to be measured is detected based on the time required from the time when the ultrasonic wave is transmitted by the wave transmitting means to the time when the ultrasonic wave is received by the plurality of receiving elements, and the plurality of received waves Detecting means for detecting the direction of the object to be measured based on a time difference between the received signals from each of the elements;
The ultrasonic wave transmitted by the wave transmitting means is a waveform of one cycle;
One receiving element of the plurality of receiving elements is arranged at the center of a polygon or a circle, and each of the other receiving elements is further away from the adjacent other receiving element than the one receiving element. The ultrasonic object detection device is arranged on the side of the polygon or the circle so that the distance to the polygon becomes longer.   The ultrasonic object detection device according to claim 1, wherein the polygon is a regular polygon.   The ultrasonic object detection device according to claim 2, wherein the regular polygon is a square.