WO2020213054A1 - Obstacle detection device - Google Patents

Abstract

According to the present invention, a first position locating unit (19) locates a two-dimensional coordinate range of an obstacle by using the distance to the obstacle and the position of a sonar sensor that receives a reflection wave, when the distance to the obstacle is equal to or greater than a reference distance (Dx) and the strength of the reflection wave reflected by this obstacle is equal to or greater than a first threshold (Th1). A second position locating unit (21) locates the two-dimensional coordinate position of the obstacle by performing an opening synthesis process by using the distance to the obstacle, when the distance to the obstacle is shorter than the reference distance (Dx) and the strength of the reflection wave reflected by the obstacle is equal to or greater than a second threshold (Th2).

Description

Obstacle detector

The present invention relates to an obstacle detection device that detects an obstacle using ultrasonic waves.

When at least one of the own vehicle or the obstacle moves and the own vehicle and the obstacle approach each other, the obstacle detection device mounted on the vehicle evaluates the position of the obstacle and performs brake control or steering control, etc. It is required to do and avoid collisions. Here, when a low-cost ultrasonic distance measuring sensor (hereinafter referred to as "sona sensor") is used for obstacle detection, the position of the obstacle in the medium-short distance region is aperture synthesis processing or two circles. It is evaluated accurately by intersection processing. On the other hand, in the long-distance region, the region where the detection ranges of the adjacent ultrasonic distance measuring sensors overlap is narrowed, so that the position evaluation accuracy by the aperture synthesis process or the like is lowered.

By the way, the detection device according to Patent Document 1 has a configuration in which an obstacle can be detected at a longer distance by increasing the amplitude of ultrasonic waves.

JP-A-2018-54582

Even if the sonar sensor increases the detectable distance by increasing the amplitude of ultrasonic waves, it is difficult to expand the area where the detection ranges overlap in the long-distance area. Therefore, even if the sonar sensor can detect the presence of an obstacle in a long distance region, the position evaluation accuracy remains low.

The present invention has been made to solve the above problems, and an object of the present invention is to evaluate the position of an obstacle in a medium-short distance region and a long-distance region.

The obstacle detection device according to the present invention includes a plurality of sonar sensors provided on one side of the vehicle, and a transmission / reception unit that transmits exploration waves using the plurality of sonar sensors and receives the reflected waves reflected by the exploration waves. , The distance calculation unit that calculates the distance to the obstacle using the transmission / reception results of the exploration wave and the reflected wave, and the distance to the obstacle are set based on the size of the overlapping area where the detection ranges of the adjacent sonar sensors overlap. When the distance to the obstacle is greater than or equal to the reference distance, the intensity of the reflected wave used to calculate the distance to the obstacle is greater than or equal to the first threshold. The distance to the obstacle calculated from the first intensity determination unit that determines whether or not the intensity is, and the reflected wave whose intensity is determined by the first intensity determination unit to be equal to or higher than the first threshold value, and the sonar sensor that receives the reflected wave. The intensity of the reflected wave used to calculate the distance to the obstacle when the distance to the obstacle is less than the reference distance and the first position evaluation part that evaluates the two-dimensional coordinate range of the obstacle using the position. Opening using the distance between the second intensity determination unit that determines whether or not is equal to or greater than the second threshold and the obstacle calculated from the reflected wave whose intensity is determined by the second intensity determination unit to be equal to or greater than the second threshold. It is provided with a second position evaluation unit that performs synthesis processing and evaluates the two-dimensional coordinate positions of obstacles.

According to the present invention, the two-dimensional coordinate position evaluation method of the obstacle is used properly depending on whether or not the distance to the obstacle is equal to or more than the reference distance. Can be rated.

It is a block diagram which shows the structural example of the obstacle detection apparatus which concerns on Embodiment 1. FIG. It is a figure which shows the example of the detection range and the reference distance of the sonar sensor in Embodiment 1. FIG. It is a flowchart which shows the operation example of the obstacle detection apparatus which concerns on Embodiment 1. FIG. It is a figure which shows the setting example of the detection range in a long-distance region of the 1st sonar sensor in Embodiment 1. FIG. It is a graph which shows the setting example of the 1st threshold value in Embodiment 1. FIG. It is a graph which shows the setting example of the 1st threshold value and the 2nd threshold value in Embodiment 1. FIG. It is a block diagram which shows the structural example of the obstacle detection apparatus which concerns on Embodiment 2. FIG. It is a graph which shows the setting example of the 1st threshold value, the 2nd threshold value and the 3rd threshold value in Embodiment 2. FIG. It is a figure which shows the setting example of the 3rd threshold value in Embodiment 2. It is a block diagram which shows the structural example of the obstacle detection apparatus which concerns on Embodiment 3. It is a flowchart which shows the operation example of the obstacle detection apparatus which concerns on Embodiment 3. It is a figure which shows the example of the tracking range when the relative speed is slow in Embodiment 3. It is a figure which shows the example of the tracking range when the relative speed is high in Embodiment 3. It is a figure which shows the example of the detection range of the long-distance region of the sonar sensor in Embodiment 4. It is a figure which shows the example of the detection range of the long-distance region of the sonar sensor in Embodiment 5. 6 is a graph showing a setting example of a second threshold value, a fourth threshold value, and a fifth threshold value in the fifth embodiment. It is a figure which shows an example of the hardware configuration of the obstacle detection apparatus which concerns on each embodiment. It is a figure which shows another example of the hardware composition of the obstacle detection apparatus which concerns on each embodiment.

Hereinafter, in order to explain the present invention in more detail, a mode for carrying out the present invention will be described with reference to the accompanying drawings.
Embodiment 1.
FIG. 1 is a block diagram showing a configuration example of the obstacle detection device 10 according to the first embodiment. The obstacle detection device 10 is mounted on the vehicle and detects obstacles around the vehicle. The obstacle detection device 10 includes a first sonar sensor 11, a second sonar sensor 12, a third sonar sensor 13, a fourth sonar sensor 14, a transmission / reception unit 15, a distance calculation unit 16, a distance determination unit 17, a first strength determination unit 18, and a first. It includes a 1-position rating unit 19, a second strength determination section 20, and a second position rating section 21.

FIG. 2 is a diagram showing an example of the detection range and the reference distance of the sonar sensor in the first embodiment. FIG. 2 shows a state in which the vehicle 1 is viewed from above, and the front-rear direction of the vehicle 1 is the X-axis and the vehicle width direction is the Y-axis. In the example of FIG. 2, the first sonar sensor 11, the second sonar sensor 12, the third sonar sensor 13, and the fourth sonar sensor 14 are installed in a row at equal intervals at the rear of the vehicle 1. That is, the direction in which the first sonar sensor 11, the second sonar sensor 12, the third sonar sensor 13, and the fourth sonar sensor 14 are arranged is the same as the Y-axis direction. The installation positions of the first sonar sensor 11, the second sonar sensor 12, the third sonar sensor 13, and the fourth sonar sensor 14 are not limited to the rear part of the vehicle 1.

In general, the detection range of a sonar sensor becomes narrower as the distance from the sonar sensor increases. Therefore, in the long-distance region, the region where the detection ranges of the adjacent sonar sensors overlap is also narrowed. In the aperture synthesis process, it is desirable that the detection ranges of adjacent sonar sensors overlap, but in the long-distance region, the areas where the detection ranges overlap are narrow or the detection ranges do not overlap, so the longer the distance, the lower the position evaluation accuracy. .. Therefore, in the first embodiment, the distance at which the overlapping regions where the detection ranges of the adjacent sonar sensors overlap is set as the reference distance Dx. In the medium-short distance region A2, which is closer to the sonar sensor than the reference distance Dx, the detection ranges overlap, so that highly accurate obstacle position evaluation by aperture synthesis processing is possible.

In the example of FIG. 2, a second threshold Th2 is set so that the detection ranges of adjacent sonar sensors overlap with respect to the medium-short distance region A2 less than the reference distance Dx. The second threshold Th2 will be described later. In this medium-short distance region A2, the detection range 11-2 of the first sonar sensor 11 and the detection range 12-2 of the second sonar sensor 12 partially overlap. Similarly, the detection range 12-2 of the adjacent second sonar sensor 12 and the detection range 13-2 of the third sonar sensor 13, the detection range 13-2 of the third sonar sensor 13 and the detection range 14-2 of the fourth sonar sensor 14 also Each part overlaps.

For a long-distance region A1 equal to or greater than the reference distance Dx, a first threshold Th1 is set so that the detection ranges of adjacent sonar sensors do not overlap. The first threshold Th1 will be described later. In this long-distance region A1, the detection range 11-1 of the first sonar sensor 11 is a range having a width Dy in the Y-axis direction, and does not overlap with the detection range 12-1 of the second sonar sensor 12. Similarly, the detection ranges 12-1, 13-1, and 14-1 of the second sonar sensor 12, the third sonar sensor 13, and the fourth sonar sensor 14 do not overlap.

FIG. 3 is a flowchart showing an operation example of the obstacle detection device 10 according to the first embodiment. For example, while the vehicle 1 is traveling, the obstacle detection device 10 repeats the operation shown in the flowchart of FIG. 3 at predetermined time intervals.

In step ST11, the transmission / reception unit 15 transmits the exploration wave in the order of, for example, the first sonar sensor 11, the second sonar sensor 12, the third sonar sensor 13, and the fourth sonar sensor 14. Further, the transmission / reception unit 15 causes the first sonar sensor 11, the second sonar sensor 12, the third sonar sensor 13, and the fourth sonar sensor 14 to receive the reflected wave reflected by the obstacle. At this time, the transmission / reception unit 15 may cause the first sonar sensor 11, the second sonar sensor 12, the third sonar sensor 13, and the fourth sonar sensor 14 to receive the direct wave or the indirect wave. For example, the transmission / reception unit 15 transmits a search wave from the first sonar sensor 11, receives the reflected wave reflected by the search wave by an obstacle as a direct wave at the first sonar sensor 11, and at the adjacent second sonar sensor 12. Receive as an indirect wave. The transmission / reception unit 15 arbitrarily selects a sonar sensor for exploration wave transmission and direct wave reception and a sonar sensor for indirect wave reception from the first sonar sensor 11, the second sonar sensor 12, the third sonar sensor 13, and the fourth sonar sensor 14. You can select. The transmission / reception unit 15 outputs the transmission / reception result using the first sonar sensor 11, the second sonar sensor 12, the third sonar sensor 13, and the fourth sonar sensor 14 to the distance calculation unit 16. The transmission / reception results include the sonar sensor that transmitted the exploration wave, the sonar sensor that received the direct wave corresponding to this exploration wave, the time from transmission of the exploration wave to the reception of the direct wave, the intensity of the direct wave, and the indirect wave corresponding to this exploration wave. The received sonar sensor, the time from the exploration wave transmission to the indirect wave reception, the intensity of the indirect wave, and the like are included.

In step ST12, the distance calculation unit 16 uses the transmission / reception result from the transmission / reception unit 15 until each of the first sonar sensor 11, the second sonar sensor 12, the third sonar sensor 13, and the fourth sonar sensor 14 receives the reflected wave. The distance to the obstacle is calculated for each sonar sensor by the TOF (Time Of Flight) method based on the time required for. This reflected wave may be a direct wave or an indirect wave. The distance calculation unit 16 outputs the calculated distance to the obstacle together with the transmission / reception result used for this calculation to the distance determination unit 17.

In step ST13, the distance determination unit 17 determines whether or not the distance to the obstacle calculated by the distance calculation unit 16 for each sonar sensor is equal to or greater than the reference distance Dx shown in FIG. It is assumed that the reference distance Dx is given to the distance determination unit 17 in advance. When the distance determination unit 17 determines that the distance to the obstacle is equal to or greater than the reference distance Dx (step ST13 “YES”), the distance determination unit 17 outputs the distance to the obstacle and the transmission / reception result to the first strength determination unit 18. To do. On the other hand, when the distance determination unit 17 determines that the distance to the obstacle is less than the reference distance Dx (step ST13 “NO”), the second strength determination unit 20 determines the distance to the obstacle and the transmission / reception result. Output to.

In step ST14, the first intensity determination unit 18 determines whether or not the intensity of the reflected wave used to calculate the distance to the obstacle determined to be the reference distance Dx or more is the predetermined first threshold Th1 or more. Is determined. In the first embodiment, the reflected wave is limited to a direct wave. When the first intensity determination unit 18 determines that the intensity of the reflected wave is equal to or higher than the first threshold value Th1 (step ST14 “YES”), the first position evaluation unit 19 determines the distance to the obstacle and the transmission / reception result. Output to. On the other hand, when the first intensity determination unit 18 determines that the intensity of the reflected wave is less than the first threshold Th1 for all the sonar sensors (step ST14 “NO”), the operation shown in the flowchart of FIG. 3 ends.

In step ST15, the first position rating unit 19 uses the distance to the obstacle calculated from the reflected wave whose intensity is determined to be the first threshold Th1 or more, and the position of the sonar sensor that received the reflected wave. The two-dimensional coordinate range of the obstacle is evaluated. For example, in FIG. 2, when the sonar sensor that has received the reflected wave is the first sonar sensor 11, the Y-axis coordinate position of the obstacle 3 is the width Dy in the Y-axis direction that is the detection range 11-1 of the first sonar sensor 11. Become a range. The X-axis coordinate position of the obstacle 3 is a position corresponding to the distance calculated by the distance calculation unit 16.

Here, the first threshold value Th1 and the detection ranges 11-1, 12-1, 13-1, and 14-1 set by the first threshold value Th1 will be described.

FIG. 4 is a diagram showing a setting example of the detection range 11-1 of the first sonar sensor 11 in the first embodiment. FIG. 5 is a graph showing a setting example of the first threshold value Th1 in the first embodiment. The horizontal axis of the graph is the distance from the first sonar sensor 11 in the X-axis direction, and the vertical axis is the value of the first threshold Th1.

In FIG. 4, the contour level V1 of the detection sensitivity has the same intensity as the intensity of the reflected wave received by the first sonar sensor 11 (that is, the detection sensitivity) when the reference pole 2-1 is present in front of the first sonar sensor 11. The range is connected by a line. Similarly, the contour lines V2 to V6 have the same intensity as the reflected wave received by the first sonar sensor 11 when the reference poles 2-2 to 2-6 are present in front of the first sonar sensor 11, respectively. The range is connected by a line.

The width of the detection range 11-1 in the Y-axis direction is set to the above width Dy so that the detection range 11-1 of the first sonar sensor 11 and the detection range 12-1 of the second sonar sensor 12 do not overlap. In this case, the value of the contour line level V1 is the first threshold value with respect to the distance in the X-axis direction where the broken line frame deviated by 1 / 2Dy in width from the front of the first sonar sensor 11 and the contour line level V1 intersect. It is set as Th1 (V1). Similarly, the values of the contour lines V2 to V5 for each distance in the X-axis direction where the broken line frame deviated by 1/2 DY in the Y-axis direction from the front of the first sonar sensor 11 and the contour lines V2 to V6 intersect. Is set as the first thresholds Th1 (V2) to Th1 (V5). As shown in FIG. 5, the line connecting the first threshold values Th1 (V1) to Th1 (V5) is the first threshold value Th1 used in the long distance region A1 having the reference distance Dx or more.

In the first embodiment, the detection ranges 11-1, 12-1, 13-1, and 14-1 of the first sonar sensor 11, the second sonar sensor 12, the third sonar sensor 13, and the fourth sonar sensor 14 have the same size. Therefore, the first threshold Th1 is the same for all sonar sensors.

As a specific example, in the first intensity determination unit 18, the intensity of the reflected wave of the first sonar sensor 11 used for calculating the distance to the obstacle determined to be the reference distance Dx or more is set as described above. It is determined whether or not the first threshold value is Th1 or more. When the intensity of the reflected wave is equal to or higher than the first threshold value Th1 (step ST14 “YES”), this obstacle is present in the detection range 11-1. Therefore, the first position evaluation unit 19 evaluates the X-axis coordinate position of the obstacle from the distance to the obstacle, and sets the range of the detection range 11-1 in the Y-axis direction as the Y-axis coordinate position of the obstacle. Rating (step ST15). On the other hand, when the intensity of the reflected wave is less than the first threshold Th1 (step ST14 “NO”), this obstacle is outside the detection range 11-1. Therefore, the first position rating unit 19 does not rate the two-dimensional coordinate range of this obstacle. In this way, the detection range 11-1 at the reference distance Dx or more of the first sonar sensor 11 is set by the first threshold Th1.

When this obstacle exists in the detection range 12-1 of the second sonar sensor 12 instead of the detection range 11-1 of the first sonar sensor 11, the intensity of the reflected wave of the second sonar sensor 12 is higher than that of the second sonar sensor 12. The first threshold value Th1 or more set in Therefore, the first position rating unit 19 evaluates the X-axis coordinate position of the obstacle from the distance to the obstacle, and sets the range of the detection range 12-1 in the Y-axis direction as the Y-axis coordinate position of the obstacle. Rating (step ST15).

FIG. 6 is a graph showing a setting example of the first threshold value Th1 and the second threshold value Th2 in the first embodiment. The horizontal axis of the graph is the distance from the first sonar sensor 11 in the X-axis direction, and the vertical axis is the values of the first threshold Th1 and the second threshold Th2. For example, the second threshold Th2 of the first sonar sensor 11 is set to a value such that the detection range 11-2 of the first sonar sensor 11 partially overlaps the detection range 12-2 of the adjacent second sonar sensor 12. The setting method may be the same as the setting method of the first threshold value Th1, or a well-known technique may be used.

In the first embodiment, the detection ranges 11-2, 12-2, 13-2, 14-2 of the first sonar sensor 11, the second sonar sensor 12, the third sonar sensor 13, and the fourth sonar sensor 14 have the same size. Therefore, the second threshold Th2 is the same for all sonar sensors.

In step ST16 of FIG. 3, the second intensity determination unit 20 determines that the intensity of the reflected wave used to calculate the distance to the obstacle determined to be less than the reference distance Dx is equal to or higher than a predetermined second threshold value Th2. Determine if it exists. This reflected wave may be a direct wave or an indirect wave. When the second intensity determination unit 20 determines that the intensity of the reflected wave is equal to or higher than the second threshold value Th2 (step ST16 “YES”), the second position evaluation unit 21 determines the distance to the obstacle and the transmission / reception result. Output to. On the other hand, when the second intensity determination unit 20 determines that the intensity of the reflected wave is less than the second threshold Th2 for all the sonar sensors (step ST16 “NO”), the second intensity determination unit 20 ends the operation shown in the flowchart of FIG.

In step ST17, the second position rating unit 21 performs aperture synthesis processing using the distance of the obstacle calculated from the reflected wave whose intensity is determined to be equal to or higher than the second threshold value, and performs the aperture synthesis process, and the two-dimensional coordinates of the obstacle. Evaluate the position. For example, assume that the first sonar sensor 11 transmits an exploration wave, the first sonar sensor 11 receives the exploration wave as a direct wave, and the second sonar sensor 12 receives this exploration wave as an indirect wave. In this case, the second position rating unit 21 draws a circle centered on the position of the first sonar sensor 11 and having the distance to the obstacle calculated from the direct wave as the radius. Further, the second position evaluation unit 21 focuses on the position of the first sonar sensor 11 and the position of the second sonar sensor 12, and draws an ellipse using the distance to the obstacle calculated from the indirect wave. Then, the second position evaluation unit 21 evaluates the two-dimensional coordinate position of the intersection of the circle and the ellipse as the two-dimensional coordinate position of the obstacle. Further, for example, it is assumed that the first sonar sensor 11 transmits the exploration wave and receives the direct wave, and the second sonar sensor 12 also transmits the exploration wave and receives the direct wave. In this case, the second position rating unit 21 draws a circle centered on the position of the first sonar sensor 11 and having the distance to the obstacle calculated from the direct wave as the radius. Similarly, the second position rating unit 21 draws a circle centered on the position of the second sonar sensor 12 and having the distance to the obstacle calculated from the direct wave as the radius. Then, the second position evaluation unit 21 evaluates the two-dimensional coordinate position of the intersection of the two circles as the two-dimensional coordinate position of the obstacle. The second position rating unit 21 may find the intersection of the ellipse and the ellipse, or may find the intersection of three or more circles or the ellipse.

As described above, the obstacle detection device 10 according to the first embodiment includes the first sonar sensor 11, the second sonar sensor 12, the third sonar sensor 13, the fourth sonar sensor 14, the transmission / reception unit 15, the distance calculation unit 16, and the distance determination unit. 17, a first strength determination unit 18, a first position evaluation unit 19, a second strength determination unit 20, and a second position evaluation unit 21 are provided. The transmission / reception unit 15 transmits the exploration wave using the first sonar sensor 11, the second sonar sensor 12, the third sonar sensor 13, and the fourth sonar sensor 14, and receives the reflected wave reflected by the obstacle. The distance calculation unit 16 calculates the distance to the obstacle using the transmission / reception results of the exploration wave and the reflected wave. The distance determination unit 17 determines whether or not the distance to the obstacle is equal to or greater than the reference distance Dx set based on the size of the overlapping region where the detection ranges of the adjacent sonar sensors overlap. When the distance to the obstacle is equal to or greater than the reference distance Dx, the first intensity determination unit 18 determines whether or not the intensity of the reflected wave used to calculate the distance to the obstacle is equal to or greater than the first threshold Th1. To do. The first position rating unit 19 uses the distance to the obstacle calculated from the reflected wave whose intensity is determined by the first intensity determination unit 18 to be the first threshold Th1 or more, and the position of the sonar sensor that receives the reflected wave. The two-dimensional coordinate range of the obstacle is evaluated. When the distance to the obstacle is less than the reference distance Dx, the second intensity determination unit 20 determines whether or not the intensity of the reflected wave used for calculating the distance to the obstacle is the second threshold Th2 or more. To do. The second position rating unit 21 performs aperture synthesis processing using the distance of the obstacle calculated from the reflected wave whose intensity is determined by the second intensity determination unit 20 to be the second threshold Th2 or more, and performs the aperture synthesis process in two dimensions of the obstacle. Evaluate the coordinate position. With this configuration, the obstacle detection device 10 evaluates the two-dimensional coordinate position of the obstacle by the aperture synthesis process in the medium-short distance region A2 where the position evaluation accuracy by the aperture synthesis process is high, and the position evaluation accuracy by the aperture synthesis process is improved. In the low long-distance region A1, the two-dimensional coordinate range of the obstacle can be evaluated without performing the aperture synthesis process.

Further, according to the first embodiment, the detection ranges 11-1, 12-1, 13-1, in the reference distance Dx or more of the first sonar sensor 11, the second sonar sensor 12, the third sonar sensor 13, and the fourth sonar sensor 14. Reference numeral 14-1 is rectangular, and the detection ranges of adjacent sonar sensors do not overlap. With this configuration, the obstacle detection device 10 has the respective detection ranges 11-1, 12-1, 13-1 as the resolution of the position evaluation in the Y-axis direction in the long-distance region A1 where the position evaluation accuracy by the aperture synthesis process is low. , 14-1 can obtain a resolution corresponding to the width in the Y-axis direction.

The number of sonar sensors included in the obstacle detection device 10 is at least two, preferably three or more.

Embodiment 2.
FIG. 7 is a block diagram showing a configuration example of the obstacle detection device 10 according to the second embodiment. The obstacle detection device 10 according to the second embodiment has a configuration in which a boundary position determination unit 22 is added to the obstacle detection device 10 of the first embodiment shown in FIG. In FIG. 7, the same or corresponding parts as those in FIGS. 1 to 6 are designated by the same reference numerals, and the description thereof will be omitted.

FIG. 8 is a graph showing a setting example of the first threshold value Th1 and the second threshold value Th2 and the third threshold value Th3 in the second embodiment. The horizontal axis of the graph is the distance from the sonar sensor in the X-axis direction, and the vertical axis is the values of the first threshold Th1, the second threshold Th2, and the third threshold Th3. The third threshold Th3 is a value larger than the first threshold Th1.

FIG. 9 is a diagram showing a setting example of the third threshold value Th3 in the second embodiment. As shown in FIG. 9, in the long-distance region A1 of the reference distance Dx or more, the obstacle 4 exists at the boundary position between the detection range 12-1 of the second sonar sensor 12 and the detection range 13-1 of the third sonar sensor 13. To do. Further, the obstacle 5 exists in the detection range 12-1 of the second sonar sensor 12.

In the situation of FIG. 9, when the second sonar sensor 12 transmits the exploration wave, the second sonar sensor 12 receives the direct wave reflected by the obstacle 4 and the direct wave reflected by the obstacle 5. The third sonar sensor 13 receives the indirect wave reflected by the obstacle 4 and the indirect wave reflected by the obstacle 5. The first sonar sensor 11 receives the indirect wave reflected by the obstacle 5.

In the situation of FIG. 9, the indirect wave path 4a reflected by the obstacle 4 existing at the boundary position forms an isosceles triangle, and at this time, the transmission / reception efficiency is maximized. On the other hand, since the indirect wave path 5a reflected by the obstacle 5 existing in the detection range 12-1 does not form an isosceles triangle, the transmission / reception efficiency of the path 5a is lower than the transmission / reception efficiency of the path 4a. Therefore, even if the length of the path 4a and the length of the path 5a are the same, the intensity of the indirect wave of the path 4a received by the third sonar sensor 13 is larger than the intensity of the indirect wave of the path 5a. Therefore, in the second embodiment, in order to discriminate between the indirect wave of the path 4a and the indirect wave of the path 5a, a third threshold value Th3 larger than the first threshold value Th1 is set as shown in FIG.

Next, the operation of the obstacle detection device 10 will be described.
In the second embodiment, the distance determination unit 17 has a distance to an obstacle of any one of the first sonar sensor 11, the second sonar sensor 12, the third sonar sensor 13, and the fourth sonar sensor 14 of the reference distance Dx or more. If it is determined, the distance to the obstacle and the transmission / reception result are output to the boundary position determination unit 22.

When the distance determination unit 17 determines that the distance of the obstacle is equal to or greater than the reference distance Dx, the boundary position determination unit 22 causes one of the adjacent sonar sensors to directly wave based on the transmission / reception result from the distance determination unit 17. Receive and determine if the other has received an indirect wave. When the boundary position determination unit 22 determines that one of the adjacent sonar sensors receives the direct wave and the other receives the indirect wave, this obstacle may exist at the boundary position of the detection range of the adjacent sonar sensor. Judged as having sex. The boundary position determination unit 22 outputs the determination result of whether or not the obstacle exists at the boundary position to the first strength determination unit 18a together with the distance to the obstacle and the transmission / reception result.

The first intensity determination unit 18a holds a third threshold value Th3 for indirect wave comparison in addition to the first threshold value Th1 for direct wave comparison. When the reflected wave is a direct wave in the long distance region A1 of the reference distance Dx or more, the first intensity determining unit 18a makes a comparison with the first threshold value Th1 as in the first embodiment, and the reflected wave is an indirect wave. If is, the comparison with the third threshold value Th3 is performed. When the first intensity determination unit 18a determines that the intensity of the indirect wave is the third threshold value Th3 or more, the first position evaluation unit 19a determines the distance of the obstacle, the transmission / reception result, and the presence of the obstacle at the boundary position. Output to. On the other hand, when the first intensity determination unit 18a determines that the intensity of the indirect wave is less than the third threshold value Th3, it does not output to the first position evaluation unit 19a because the obstacle does not exist at the boundary position.

When the first strength determination unit 18a notifies that the obstacle exists at the boundary position in the position evaluation of the obstacle, the first position evaluation unit 19a evaluates the boundary position as the Y-axis coordinate position of the obstacle. To do.

For example, when the obstacle 4 exists in FIG. 9 and the second sonar sensor 12 transmits the exploration wave, the boundary position determination unit 22 receives the direct wave from the second sonar sensor 12 and is adjacent to the second sonar sensor 12. 3 It is determined that the sonar sensor 13 has received the indirect wave. Therefore, the boundary position determination unit 22 determines that the obstacle whose distance has been calculated by the distance calculation unit 16 may exist at the boundary positions of the detection ranges 12-1 and 13-1. The first intensity determination unit 18a determines that the intensity of the indirect wave used to calculate the distance to the obstacle is the third threshold Th3 or more, and the obstacle has a detection range of 12-1, 13-1. The fact that it exists at the boundary position of is output to the first position rating unit 19a.

In FIG. 9, when the obstacle 5 exists and the second sonar sensor 12 transmits the exploration wave, the boundary position determination unit 22 receives the wave directly from the second sonar sensor 12 and the first sonar sensor adjacent to the second sonar sensor 12. It is determined that the 11 and the third sonar sensor 13 have received the indirect wave. Therefore, in the boundary position determination unit 22, the obstacle whose distance is calculated by the distance calculation unit 16 is placed at the boundary position of the detection ranges 12-1 and 11-1 and the boundary position of the detection ranges 12-1 and 13-1. Determine that it may exist. However, since the first intensity determination unit 18a determines that the intensity of the indirect wave used to calculate the distance to the obstacle is less than the third threshold Th3, the determination result of the boundary position determination unit 22 is Rejected.

As described above, the obstacle detection device 10 according to the second embodiment includes the boundary position determination unit 22. When the distance of the obstacle is equal to or greater than the reference distance Dx and one of the adjacent sonar sensors receives the direct wave and the other receives the indirect wave, the boundary position determination unit 22 indicates that the obstacle is the adjacent sonar sensor. It is determined that it exists at the boundary position of the detection range of. As described above, in the first embodiment, the obstacle detection device 10 uses only the direct wave at the reference distance Dx or more, but in the second embodiment, the indirect wave is also used in addition to the direct wave. Thereby, in the second embodiment, it is possible to determine whether an obstacle exists in the detection range of the long-distance region A1 or whether the obstacle exists at the boundary position of the detection range of the long-distance region A1. Therefore, the resolution in the Y-axis direction in the position evaluation of the first position evaluation unit 19a is further improved.

Further, according to the first embodiment, when the boundary position determination unit 22 determines that the obstacle exists at the boundary position, the first intensity determination unit 18a uses the third threshold value Th3 which is larger than the first threshold value Th1. To determine the intensity of the indirect wave. As a result, the first intensity determination unit 18a can adopt the indirect wave reflected by the obstacle only when the obstacle exists at the boundary position of the adjacent detection range in the long distance region A1. Therefore, the position evaluation accuracy of the first position evaluation unit 19a is further improved.

Embodiment 3.
FIG. 10 is a block diagram showing a configuration example of the obstacle detection device 10 according to the third embodiment. The obstacle detection device 10 according to the third embodiment has a configuration in which an obstacle tracking unit 23 and a collision determination unit 24 are added to the obstacle detection device 10 of the first embodiment shown in FIG. .. In FIG. 10, the same or corresponding parts as those in FIGS. 1 to 6 are designated by the same reference numerals, and the description thereof will be omitted.
Here, an example is shown in which the obstacle tracking unit 23 and the collision determination unit 24 according to the third embodiment are added to the obstacle detection device 10 of the first embodiment, but the obstacle tracking unit 23 and The collision determination unit 24 can also be added to the obstacle detection device 10 of the second embodiment.

Further, the obstacle detection device 10 of the third embodiment is connected to the vehicle control unit 25. The vehicle control unit 25 has, for example, a function of operating the brake of the vehicle 1 to reduce the impact at the time of a collision (so-called collision damage mitigation) when the possibility of collision with an obstacle is high. Brake) or a function to issue an alarm to the driver (so-called collision prevention warning system) to prevent a collision. The vehicle control unit 25 outputs information such as the speed and steering angle of the vehicle 1 to the obstacle tracking unit 23 and the collision determination unit 24 as needed.

FIG. 11 is a flowchart showing an operation example of the obstacle detection device 10 according to the third embodiment. For example, while the vehicle 1 is traveling, the obstacle detection device 10 repeats the operation shown in the flowchart of FIG. 11 at predetermined time intervals.

In step ST21, the first sonar sensor 11, the second sonar sensor 12, the third sonar sensor 13, the fourth sonar sensor 14, the transmission / reception unit 15, the distance calculation unit 16, the distance determination unit 17, the first strength determination unit 18, and the first position evaluation unit. 19 and the second strength determination unit 20 perform the operations shown in the flowchart of FIG. Then, when the first position rating unit 19 evaluates the two-dimensional coordinate range of the obstacle, or when the second position rating unit 21 evaluates the two-dimensional coordinate position of the obstacle, the two-dimensional coordinate range or the two-dimensional coordinate position Is output to the obstacle tracking unit 23.

In step ST22, the obstacle tracking unit 23 receives at least one of the two-dimensional coordinate range or the two-dimensional coordinate position of the obstacle from at least one of the first position evaluation unit 19 and the second position evaluation unit 21. In the obstacle tracking unit 23, the two-dimensional coordinate range or the two-dimensional coordinate position of the obstacle received from at least one of the first position evaluation unit 19 and the second position evaluation unit 21 this time is the first position evaluation unit 19 last time. Alternatively, it is determined whether or not the obstacle falls within the two-dimensional coordinate range or the tracking range set for the two-dimensional coordinate position of the obstacle received from at least one of the second position evaluation units 21. When the obstacle tracking unit 23 determines that the two-dimensional coordinate range or the two-dimensional coordinate position of the obstacle this time falls within the tracking range, the obstacle tracked in the current step ST21 and the position rated in the previous step ST21. It is determined that the obstacles that have been made are the same obstacles. On the other hand, when the obstacle tracking unit 23 determines that the two-dimensional coordinate range or the two-dimensional coordinate position of the obstacle this time is out of the tracking range, the obstacle whose position has been evaluated in this step ST21 and the previous step ST21 It is determined that the obstacle whose position is evaluated in 1 is a different obstacle. In that case, the obstacle tracking unit 23 sets a new tracking range for the obstacle whose position has been evaluated in step ST21 this time, and adds it to the next tracking target. In this way, the obstacle tracking unit 23 tracks the two-dimensional coordinate range or the two-dimensional coordinate position of the same obstacle that changes with time. The obstacle tracking unit 23 outputs the two-dimensional coordinate range or the two-dimensional coordinate position of the same obstacle to be tracked to the collision determination unit 24.

The obstacle tracking unit 23 changes the size of the above tracking range depending on whether the same obstacle exists in the long-distance region A1 or in the medium-short-distance region A2. The obstacle tracking unit 23 relatively increases the tracking range when the same obstacle exists in the long-distance region A1, and relatively decreases the tracking range when the same obstacle moves to the medium-short distance region A2. To do.

Further, the obstacle tracking unit 23 changes the size of the tracking range based on the relative speed between the vehicle 1 and the same obstacle. The obstacle tracking unit 23 changes the tracking range to a size corresponding to the relative speed by using, for example, a function or a table that defines the correspondence between the relative speed and the size of the tracking range. When the relative speed is slow, the obstacle tracking unit 23 relatively increases the tracking range, and when the relative speed is high, the tracking range is relatively small.

FIG. 12 is a diagram showing an example of a tracking range when the relative speed is slow in the third embodiment. In FIG. 12, obstacles 30, 31, and 32 are positioned in this order by the first position rating unit 19, and then obstacles 33, 34, and 35 are position rated in this order by the second position rating unit 21. To do. Further, in the example of FIG. 12, the obstacle 30 is detected by the first sonar sensor 11, the obstacle 31 is detected by both the first sonar sensor 11 and the second sonar sensor 12, and the obstacle 32 is detected by the second sonar sensor 12. It is assumed that it has been done. As the Y-axis coordinate position of the obstacle detected simultaneously by the two sonar sensors such as the obstacle 31, the center position of both sonar sensors or the position distributed according to the intensity of the direct wave received by both sonar sensors is used. In this way, since the Y-axis coordinate range is the Y-axis coordinate position of one point, the two-dimensional coordinate range is treated as the two-dimensional coordinate position below.

In FIG. 12, the obstacle tracking unit 23 calculates the moving speeds of the obstacles 30 and 31 based on the distance difference between the two-dimensional coordinate position of the obstacle 30 and the two-dimensional coordinate position of the obstacle 31. Further, the obstacle tracking unit 23 acquires the speed of the vehicle 1 from the vehicle control unit 25. Then, the obstacle tracking unit 23 calculates the relative speed between the vehicle 1 and the obstacles 30 and 31, and based on the calculated relative speed, determines the size of the tracking range 40 set in the obstacle 30 in the X-axis direction. change. Further, since the obstacle 30 exists in the long-distance region A1 having low position evaluation accuracy, the obstacle tracking unit 23 determines the size of the tracking range 40 in the Y-axis direction by the position evaluation resolution of the first position evaluation unit 19. Set 1.5 to 2 times. In the example of FIG. 2, since the position evaluation resolution of the first position evaluation unit 19 is the width Dy in the Y-axis direction, the obstacle tracking unit 23 sets the size of the tracking range 40 in the Y-axis direction to 1.5 Dy to 2 Dy. To do. Since the obstacle 31 is included in the tracking range 40, the obstacle tracking unit 23 determines that the obstacle 30 and the obstacle 31 are the same obstacle. The obstacle tracking unit 23 sets the tracking ranges 41 and 42 for the obstacles 31 and 32 in the same manner.

After that, the obstacle tracking unit 23 calculates the moving speeds of the obstacles 33 and 34 based on the distance difference between the two-dimensional coordinate position of the obstacle 33 and the two-dimensional coordinate position of the obstacle 34. Further, the obstacle tracking unit 23 acquires the speed of the vehicle 1 from the vehicle control unit 25. Then, the obstacle tracking unit 23 calculates the relative speed between the vehicle 1 and the obstacles 33 and 34, and based on the calculated relative speed, determines the size of the tracking range 43 set in the obstacle 33 in the X-axis direction. change. Further, since the obstacle 33 exists in the medium / short distance region A2 having high position evaluation accuracy, the obstacle tracking unit 23 determines the size of the tracking range 43 in the Y-axis direction by the position evaluation resolution of the second position evaluation unit 21. Set to 1.5 to 2 times. Since the position evaluation resolution of the second position evaluation unit 21 is higher than the position evaluation resolution of the first position evaluation unit 19, the size of the tracking range 43 in the Y-axis direction is larger than that of the tracking ranges 40, 41, 42 in the Y-axis direction. It is smaller than the resolution. Since the obstacle 34 is included in the tracking range 43, the obstacle tracking unit 23 determines that the obstacle 33 and the obstacle 34 are the same obstacle. The obstacle tracking unit 23 sets the tracking ranges 44 and 45 for the obstacles 34 and 35 in the same manner.

FIG. 13 is a diagram showing an example of a tracking range when the relative speed is high in the third embodiment. The obstacle tracking unit 23 sets tracking ranges 40a, 41a, 42a, 43a, 44a for obstacles 30a, 31a, 32a, 33a, 34a, as in the example shown in FIG. 12, where the relative speed is slow. However, since the example shown in FIG. 13 has a higher relative velocity than the example shown in FIG. 12, the magnitudes of the tracking ranges 40a, 41a, 42a, 43a, 44a in the X-axis direction are the tracking ranges 40, 41. , 42, 43, 44, 45 are larger than the size in the X-axis direction. For example, since the obstacle 31a is included in the tracking range 40a set for the obstacle 30a, the obstacle tracking unit 23 determines that the obstacle 30a and the obstacle 31a are the same obstacle.

In step ST23, the collision determination unit 24 obtains the locus 50 shown in FIG. 12 or the locus 50a shown in FIG. 13 using the two-dimensional coordinate positions of the same obstacle output from the obstacle tracking unit 23, and obtains the locus 50a. Predict the course of the obstacle to be tracked based on. The collision determination unit 24 may give a width to the course when predicting the course of the obstacle. The collision determination unit 24 acquires the steering angle of the vehicle 1 from the vehicle control unit 25, predicts the course of the vehicle 1, and determines whether or not a collision is possible by comparing the predicted course of the vehicle 1 with the course of an obstacle. To do. Since the collision determination unit 24 may determine whether or not a collision is possible using a well-known technique, detailed description here will be omitted. Further, the collision determination unit 24 calculates the collision margin time (TTC) when it is determined that the vehicle 1 and an obstacle may collide with each other. The collision margin time is an index showing how many seconds are left when the relative speed between the vehicle 1 and the obstacle is maintained. The collision determination unit 24 outputs the collision possibility determination result and the collision margin time to the vehicle control unit 25.

The vehicle control unit 25 activates the brake of the vehicle 1 or issues an alarm to the driver based on the collision possibility determination result output from the collision determination unit 24 and the collision margin time.

As described above, the obstacle detection device 10 according to the third embodiment includes an obstacle tracking unit 23. The obstacle tracking unit 23 has a plurality of obstacles whose two-dimensional coordinate range has been evaluated by the first position evaluation unit 19 or whose two-dimensional coordinate position has been evaluated by the second position evaluation unit 21 at predetermined time intervals. If is within the tracking range, the plurality of obstacles are determined to be the same obstacle. Further, the obstacle tracking unit 23 increases the tracking range in proportion to the relative speed between the vehicle 1 and the same obstacle, and when the distance to the same obstacle is equal to or greater than the reference distance Dx, the reference distance Dx Make it larger than if it is less than. With this configuration, when an obstacle exists in a long-distance region A1 having a reference distance Dx or more, the obstacle tracking unit 23 has low positioning accuracy of the obstacle, so that the tracking range can be set wide and tracking can be easily performed. can do. Therefore, the obstacle tracking unit 23 can track the obstacle from the long-distance region A1 having low position evaluation accuracy. Further, the obstacle tracking unit 23 can individually change the size of the tracking range in the X-axis direction and the Y-axis direction according to the distance to the obstacle and the relative speed between the obstacle and the vehicle 1. Therefore, the obstacle tracking unit 23 can accurately determine whether or not the obstacles are the same.

Further, the obstacle detection device 10 according to the third embodiment includes a collision determination unit 24. The collision determination unit 24 determines whether or not the same obstacle collides with the vehicle 1 and calculates the time until the collision. Since the obstacle tracking unit 23 enables tracking of obstacles from the long-distance region A1, the collision determination unit 24 collides more accurately at a distance as compared with the conventional obstacle position evaluation only by the aperture synthesis process. It is possible to judge whether or not it is possible.

Embodiment 4.
In the first to third embodiments, the detection ranges of the adjacent sonar sensors do not overlap in the long-distance region A1. On the other hand, in the fourth embodiment, the detection ranges of the adjacent sonar sensors partially overlap in the long-distance region A1.

FIG. 14 is a diagram showing an example of the detection range of the long-distance region A1 of the sonar sensor according to the fourth embodiment. In FIG. 14, the detection range of the medium-short distance region A2 is not shown.
In the long-distance region A1, the detection range 11-1a of the first sonar sensor 11, the detection range 12-1a of the second sonar sensor 12, the detection range 13-1a of the third sonar sensor 13, and the detection range 14-1a of the fourth sonar sensor 14 Each is a range having a width Dya (for example, Dya = 2Dy) in the Y-axis direction. The detection range 11-1a of the first sonar sensor 11 overlaps the detection range 12-1a of the second sonar sensor 12 adjacent to the first sonar sensor 11 by the width Dyb (<1 / 2Dya) in the Y-axis direction. That is, in the Y-axis direction, the detection range 11-1a and the detection range 12-1a overlap by the width Dyb. The detection range 12-1a of the second sonar sensor 12 overlaps the detection ranges 11-1a and 13-1a on both sides with a width of Dyb. Similarly, the detection range 13-1a of the third sonar sensor 13 overlaps the detection ranges 12-1a and 14-1a on both sides by a width Dyb. The detection range 14-1a of the fourth sonar sensor 14 overlaps the adjacent detection range 13-1a by the width Dyb. As described above, the long-distance region A1 is divided into four as shown in FIG. 2 in the first embodiment, but is divided into seven as shown in FIG. 14 in the fourth embodiment.

As described in the first embodiment, the size of the detection ranges 11-1a, 12-1a, 13-1a, 14-1a is set by the first threshold value Th1.

Since the configuration of the obstacle detection device 10 according to the fourth embodiment is the same as the configuration shown in FIG. 1 of the first embodiment on the drawing, FIG. 1 will be referred to below.
Here, an example is shown in which the detection ranges 11-1a, 12-1a, 13-1a, 14-1a shown in FIG. 14 are applied to the obstacle detection device 10 of the first embodiment. The detection ranges 11-1a, 12-1a, 13-1a, 14-1a can also be applied to the obstacle detection device 10 of the third embodiment.

The first position rating unit 19 evaluates the Y-axis coordinate range of the obstacle based on the overlap of the detection ranges of the sonar sensors that have received the direct waves determined to have the intensity equal to or higher than the first threshold Th1. For example, as shown in FIG. 14, it is assumed that the obstacle 6 exists in the region where the detection range 11-1a and the detection range 12-1a overlap. In this case, the first sonar sensor 11 and the second sonar sensor 12 receive a direct wave having an intensity equal to or higher than the first threshold Th1. Therefore, the first position evaluation unit 19 covers an area where the detection range 11-1a of the first sonar sensor 11 indicated by the thick black line and the detection range 12-1a of the second sonar sensor 12 overlap in the Y-axis direction as an obstacle. It is rated as the Y-axis coordinate range 6a of 6.

Further, for example, as shown in FIG. 14, it is assumed that the obstacle 7 exists in the area of only the detection range 13-1a. In this case, only the third sonar sensor 13 receives a direct wave having an intensity equal to or higher than the first threshold Th1. Therefore, the first position evaluation unit 19 detects the detection range 12-1a of the second sonar sensor 12 and the fourth sonar sensor 14 in the detection range 13-1a of the third sonar sensor 13 indicated by the thick black line in the Y-axis direction. The area that does not overlap with the range 14-1a is evaluated as the Y-axis coordinate range 7a of the obstacle 7.

As described above, according to the fourth embodiment, the detection ranges 11-1a, 12-1a, 13 of the first sonar sensor 11, the second sonar sensor 12, the third sonar sensor 13, and the fourth sonar sensor 14 at the reference distance Dx or more. -1a and 14-1a are square, and the detection range of the adjacent sonar sensors is in the Y-axis direction in which the first sonar sensor 11, the second sonar sensor 12, the third sonar sensor 13, and the fourth sonar sensor 14 are arranged. Overlap less than 1/2. With this configuration, the resolution in the Y-axis direction in the position evaluation of the first position evaluation unit 19 is further improved.

Embodiment 5.
In the first to fourth embodiments, the distance between the adjacent sonar sensors in the Y-axis direction is uniform with the width Dy, and the positions of the adjacent sonar sensors in the X-axis direction are also uniform. On the other hand, in the fifth embodiment, the distance in the Y-axis direction and the position in the X-axis direction between adjacent sonar sensors are different, and the arrangement is symmetrical with respect to the vehicle 1.

FIG. 15 is a diagram showing an example of the detection range of the long-distance region A1 of the sonar sensor in the fifth embodiment. In FIG. 15, the detection range of the medium-short distance region A2 is not shown. In the Y-axis direction, the distance between the first sonar sensor 11 and the second sonar sensor 12 is equal to the distance between the third sonar sensor 13 and the fourth sonar sensor 14. In the Y-axis direction, the distance between the second sonar sensor 12 and the third sonar sensor 13 is larger than the distance between the first sonar sensor 11 and the second sonar sensor 12. Further, in the X-axis direction, the second sonar sensor 12 and the third sonar sensor 13 are arranged in front of the first sonar sensor 11 and the fourth sonar sensor 14.

FIG. 16 is a graph showing a setting example of the second threshold value Th2, the fourth threshold value Th4, and the fifth threshold value Th5 in the fifth embodiment. The horizontal axis of the graph is the distance from the sonar sensor in the X-axis direction, and the vertical axis is the values of the second threshold Th2, the fourth threshold Th4, and the fifth threshold Th5. The fourth threshold value Th4 is a value larger than the fifth threshold value Th5.

In the long-distance region A1, the detection range 11-1b of the first sonar sensor 11 and the detection range 14-1b of the fourth sonar sensor 14 are ranges having a width Dyc in the Y-axis direction, respectively. The detection range 12-1b of the second sonar sensor 12 and the detection range 13-1b of the third sonar sensor 13 are ranges having a width Dyd (> Dyc) in the Y-axis direction, respectively. The detection range 11-1b of the first sonar sensor 11 overlaps the detection range 12-1b of the second sonar sensor 12 adjacent to the first sonar sensor 11 by the width Dye (<1 / 2Dyc) in the Y-axis direction. That is, in the Y-axis direction, the detection range 11-1b and the detection range 12-1b overlap by the width Dye. The detection range 12-1b of the second sonar sensor 12 overlaps with the adjacent detection range 11-1b by the width Dye. Similarly, the detection range 13-1b of the third sonar sensor 13 overlaps the adjacent detection range 14-1b by the width Dye. The detection range 14-1b of the fourth sonar sensor 14 overlaps the adjacent detection range 13-1b by the width Dye. As described above, the long-distance region A1 is divided into four as shown in FIG. 2 in the first embodiment, but is divided into six as shown in FIG. 15 in the fifth embodiment.

In the fifth embodiment, the detection range 11-1b of the first sonar sensor 11 and the detection range 14-1b of the fourth sonar sensor 14 have the same size, and the sizes of the detection ranges 11-1b and 14-1b are the same. , Is set by the fourth threshold Th4. Further, the detection range 12-1b of the second sonar sensor 12 and the detection range 13-1b of the third sonar sensor 13 have the same size, and the sizes of these detection ranges 12-1b and 13-1b are the fifth threshold values. It is set by Th5. Since the method of setting the fourth threshold value Th4 and the fifth threshold value Th5 is the same as the setting method of the first threshold value Th1, the description thereof will be omitted.

Since the configuration of the obstacle detection device 10 according to the fifth embodiment is the same as the configuration shown in FIG. 1 of the first embodiment on the drawing, FIG. 1 will be referred to below.
Here, an example is shown in which the detection ranges 11-1b, 12-1b, 13-1b, 14-1b shown in FIG. 15 are applied to the obstacle detection device 10 of the first embodiment. The detection ranges 11-1b, 12-1b, 13-1b, and 14-1b are also applicable to the obstacle detection device 10 of the third embodiment.

The first intensity determination unit 18 holds the fourth threshold value Th4 and the fifth threshold value Th5 instead of the first threshold value Th1. The first intensity determination unit 18 compares the intensity of the direct wave received by the first sonar sensor 11 and the fourth sonar sensor 14 with the fourth threshold value Th4 in the long distance region A1 of the reference distance Dx or more. Further, the first intensity determination unit 18 compares the intensity of the direct wave received by the second sonar sensor 12 and the third sonar sensor 13 with the fifth threshold value Th5 in the long distance region A1 of the reference distance Dx or more.

The first position rating unit 19 determines the Y-axis coordinate range of the obstacle based on the overlap of the detection ranges of the sonar sensors that have received the direct waves determined to have the intensity of the fourth threshold Th4 or more or the fifth threshold Th5 or more. To rate. Since the evaluation method of the Y coordinate range is the same as the evaluation method by the first position evaluation unit 19 of the fourth embodiment, the description thereof will be omitted.

As described above, according to the fifth embodiment, the obstacle detection device 10 has different positions of the first sonar sensor 11, the second sonar sensor 12, the third sonar sensor 13, and the fourth sonar sensor 14 in the X-axis direction. In this case as well, the two-dimensional coordinate range of the obstacle can be evaluated in the long-distance region A1 without performing the aperture synthesis process.

Finally, the hardware configuration of the obstacle detection device 10 according to each embodiment will be described.
17 and 18 are diagrams showing a hardware configuration example of the obstacle detection device 10 according to each embodiment. The transmission / reception unit 15 in the obstacle detection device 10 is a transmission circuit 103 and a reception circuit 104. The transmission circuit 103 is a circuit that applies a voltage to the first sonar sensor 11, the second sonar sensor 12, the third sonar sensor 13, and the fourth sonar sensor 14 to transmit the exploration wave. The receiving circuit 104 is a circuit that converts the voltage corresponding to the reflected wave output by the first sonar sensor 11, the second sonar sensor 12, the third sonar sensor 13, and the fourth sonar sensor 14 into a digital signal. Distance calculation unit 16, distance determination unit 17, first strength determination unit 18, 18a, first position evaluation unit 19, 19a, second strength determination unit 20, second position evaluation unit 21, boundary position in the obstacle detection device 10. The functions of the determination unit 22, the obstacle tracking unit 23, and the collision determination unit 24 are realized by the processing circuit. That is, the obstacle detection device 10 includes a processing circuit for realizing the above function. The processing circuit may be a processing circuit 100 as dedicated hardware, or a processor 101 that executes a program stored in the memory 102.

As shown in FIG. 17, when the processing circuit is dedicated hardware, the processing circuit 100 may be, for example, a single circuit, a composite circuit, a programmed processor, a parallel programmed processor, or an ASIC (Application Special Integrated Circuit). ), FPGA (Field Processor Gate Array), or a combination thereof. Distance calculation unit 16, distance determination unit 17, first strength determination unit 18, 18a, first position evaluation unit 19, 19a, second strength determination unit 20, second position evaluation unit 21, boundary position determination unit 22, obstacle The functions of the tracking unit 23 and the collision determination unit 24 may be realized by a plurality of processing circuits 100, or the functions of each unit may be collectively realized by one processing circuit 100.

As shown in FIG. 18, when the processing circuit is the processor 101, the distance calculation unit 16, the distance determination unit 17, the first intensity determination units 18, 18a, the first position evaluation units 19, 19a, and the second intensity determination unit 20, the functions of the second position evaluation unit 21, the boundary position determination unit 22, the obstacle tracking unit 23, and the collision determination unit 24 are realized by software, firmware, or a combination of software and firmware. The software or firmware is described as a program and stored in the memory 102. The processor 101 realizes the functions of each part by reading and executing the program stored in the memory 102. That is, the obstacle detection device 10 includes a memory 102 for storing a program in which the steps shown in the flowcharts of FIGS. 3 and 11 are eventually executed when executed by the processor 101. In addition, this program includes a distance calculation unit 16, a distance determination unit 17, a first strength determination unit 18, 18a, a first position evaluation unit 19, 19a, a second intensity determination unit 20, a second position evaluation unit 21, and a boundary position. It can also be said that the procedure or method of the determination unit 22, the obstacle tracking unit 23, and the collision determination unit 24 is executed by the computer.

Here, the processor 101 is a CPU (Central Processing Unit), a processing device, an arithmetic unit, a microprocessor, or the like.
The memory 102 may be a non-volatile or volatile semiconductor memory such as a RAM (Random Access Memory), a ROM (Read Only Memory), an EPROM (Erasable Programmable ROM), or a flash memory, or may be a non-volatile or volatile semiconductor memory such as a hard disk or a flexible disk. It may be a magnetic disk of the above, or an optical disk such as a CD (Compact Disc) or a DVD (Digital Versaille Disc).

The distance calculation unit 16, the distance determination unit 17, the first strength determination units 18, 18a, the first position evaluation units 19, 19a, the second strength determination unit 20, the second position evaluation unit 21, the boundary position determination unit 22, The functions of the obstacle tracking unit 23 and the collision determination unit 24 may be partially realized by dedicated hardware and partly realized by software or firmware. As described above, the processing circuit in the obstacle detection device 10 can realize the above-mentioned functions by hardware, software, firmware, or a combination thereof.

The present invention allows any combination of embodiments, modifications of any component of each embodiment, or omission of any component of each embodiment within the scope of the invention.

Since the obstacle detection device according to the present invention can start tracking obstacles from a distance, it is suitable for an obstacle detection device used in a collision damage mitigation brake, a collision prevention warning system, or the like.

1 Vehicle, 2-1 to 2-6 Reference pole, 3, 4, 5, 6, 7 Obstacles, 4a, 5a Indirect wave path, 6a, 7a Y-axis coordinate range, 10 Obstacle detection device, 11 1st Sonar Sensors, 11-1, 11-1a, 11-1b, 11-2, 12-1, 12-1a, 12-1b, 12-2, 13-1, 13-1a, 13-1b, 13-2, 14-1, 14-1a, 14-1b, 14-2 Detection range, 12 2nd sonar sensor, 13 3rd sonar sensor, 14 4th sonar sensor, 15 transmission / reception unit, 16 distance calculation unit, 17 distance determination unit, 18, 18a 1st strength determination unit, 19, 19a 1st position evaluation unit, 20 2nd strength determination unit, 21 2nd position evaluation unit, 22 boundary position determination unit, 23 obstacle tracking unit, 24 collision determination unit, 25 vehicle control unit , 30, 30a, 31, 31a, 32, 32a, 33, 33a, 34, 34a, 35 Obstacles, 41, 41a, 42, 42a, 43, 43a, 44, 44a, 45 Tracking range, 50, 50a locus, 100 processing circuit, 101 processor, 102 memory, 103 transmission circuit, 104 reception circuit, A1 long distance area, A2 medium and short distance area, Dx reference distance, Dy, Dya, Dyb, Dic, Dyd, Dye width, Th1, Th1 ( V1) to Th1 (V5) 1st threshold, Th2 2nd threshold, Th3 3rd threshold, Th4 4th threshold, Th5 5th threshold, V1 to V6 contour levels.

Claims (7)

1. Multiple sonar sensors installed on one side of the vehicle,
   A transmitter / receiver that transmits exploration waves using the plurality of sonar sensors and receives reflected waves reflected by obstacles.
   A distance calculation unit that calculates the distance to the obstacle using the transmission / reception results of the search wave and the reflected wave, and
   A distance determination unit that determines whether or not the distance to the obstacle is equal to or greater than a reference distance set based on the size of the overlapping region where the detection ranges of adjacent sonar sensors overlap.
   When the distance to the obstacle is equal to or greater than the reference distance, the first intensity determination unit for determining whether or not the intensity of the reflected wave used for calculating the distance to the obstacle is equal to or greater than the first threshold value. When,
   Using the distance to the obstacle calculated from the reflected wave whose intensity is determined by the first intensity determination unit to be equal to or higher than the first threshold value and the position of the sonar sensor that received the reflected wave, the obstacle 2 The first position rating unit that evaluates the dimensional coordinate range, and
   When the distance to the obstacle is less than the reference distance, the second intensity determination unit for determining whether or not the intensity of the reflected wave used for calculating the distance to the obstacle is equal to or greater than the second threshold value. When,
   Aperture synthesis processing is performed using the distance of the obstacle calculated from the reflected wave whose intensity is determined by the second intensity determination unit to be equal to or higher than the second threshold value, and the two-dimensional coordinate position of the obstacle is evaluated. An obstacle detection device including a second position rating unit.
2. The obstacle detection device according to claim 1, wherein the detection range of each of the plurality of sonar sensors at the reference distance or more is rectangular, and the detection ranges of adjacent sonar sensors do not overlap.
3. When the distance of the obstacle is equal to or greater than the reference distance, and one of the adjacent sonar sensors receives a direct wave and the other receives an indirect wave, the obstacle is within the detection range of the adjacent sonar sensor. The obstacle detection device according to claim 1, further comprising a boundary position determination unit that determines that the device exists at the boundary position.
4. When the boundary position determination unit determines that the obstacle exists at the boundary position, the first intensity determination unit determines the intensity of the indirect wave using a third threshold value larger than the first threshold value. The obstacle detection device according to claim 3, wherein the obstacle detection device is characterized.
5. A plurality of obstacles whose two-dimensional coordinate range has been evaluated by the first position evaluation unit or whose two-dimensional coordinate position has been evaluated by the second position evaluation unit are included in the tracking range at predetermined time intervals. In this case, an obstacle tracking unit for determining the plurality of obstacles as the same obstacle is provided.
   The obstacle tracking unit increases the tracking range in proportion to the relative speed between the vehicle and the same obstacle, and when the distance to the same obstacle is equal to or greater than the reference distance, the reference The obstacle detection device according to claim 1, wherein the distance is made larger than when the distance is less than the distance.
6. The obstacle detection device according to claim 5, further comprising a collision determination unit that determines whether or not the same obstacle collides with the vehicle and calculates the time until the collision.
7. The claim is characterized in that the detection range of each of the plurality of sonar sensors at the reference distance or more is rectangular, and the detection range of the adjacent sonar sensors overlaps by less than 1/2 in the direction in which the plurality of sonar sensors are arranged. 1. Obstacle detection device according to 1.

Images