JP2011232230A - Overhead obstacle detector, collision preventing device, and overhead obstacle detection method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an overhead obstacle detector, a collision preventing device, and an overhead obstacle detection method which are capable of obtaining a distance from a target existing above a road surface to the road surface regardless of changes in state of a road and in posture of a vehicle.SOLUTION: A first time in which laser light is returned after being emitted and an angle of elevation being an emission angle at which the laser light is emitted from an overhead target detecting means 11 are detected by overhead target detection means 11, 12, and 13, and an overhead target calculation means 15 calculates an overhead target distance and an overhead target height on the basis of the first time and the angle of elevation. Meanwhile, a second time in which laser light is reflected by the road surface and is returned to a road surface detection means and an angle of depression being an emission angle at which the laser light is emitted are detected by road surface detection means 11, 12, and 14, and a road surface height calculation means 15 calculates a road surface height on the basis of the second time and the angle of depression. A road height width calculation means 15 calculates a road height width by adding the overhead target height and the road surface height.

Description

  The present invention relates to an upper obstacle detection device, a collision prevention device, and an upper obstacle detection method for detecting an upper obstacle having a possibility of a collision based on a result of scanning the front of a vehicle using a laser beam.

  Conventionally, when a target such as an obstacle exists in front of the vehicle, there has been a demand for knowing in advance whether the vehicle can pass through without colliding with the target. In order to know in advance whether or not the vehicle can pass through, when the vehicle passes in the vicinity of the target, it is determined whether there is an appropriate space between the target in the left-right direction and the vertical direction of the vehicle. There is a need. Specifically, it has been considered to measure the azimuth and distance from the vehicle to the target using means such as a radio wave radar, and determine whether or not the vehicle can pass through based on these measured values.

  However, in the method using radio wave radar, since the divergence angle of the beam irradiated toward the target is wide, the problem is that the azimuth and distance of the obstacle cannot be measured with sufficient accuracy to determine whether or not the object can pass through as described above was there.

  In order to solve this problem, a technique using a laser radar capable of measuring with higher accuracy than a radio wave radar has been proposed (for example, see Patent Document 1). Specifically, the laser beam is irradiated from the launch point above the road surface (above the front of the vehicle) and scanned two-dimensionally, so that the distance to the lower end of the target above the road surface and the angle (azimuth) The height of the lower end of the target is compared with the height of the top of the vehicle based on the measurement result to determine whether or not the vehicle can pass through.

Japanese Patent Laid-Open No. 55-096475

  In the technique of the above-mentioned patent document 1, although the vehicle can actually pass under the target, an erroneous determination is made that the vehicle cannot pass, and a false alarm is issued according to the determination, and vice versa. However, there was a problem that an incorrect judgment was made that it was possible to pass through even though it could not pass under the target, and an alarm could not be issued according to the judgment.

  That is, in the technique of Patent Document 1, the height of the target is substantially obtained based on the road surface height at the position where the vehicle is present, and therefore the road surface height at the position where the target is present is determined. If it is different from the road surface height at the laser beam launch point, the distance from the road surface to the lower end of the target will be different from the actual value, and an erroneous determination will be made.

Specifically, as shown in FIG. 13, when passing under an overhead target 51 such as a railway or a highway, the road surface height of a portion overlapping the overhead target 51 is lower than other road surface heights. On the road, the distance R _U from the position away from the overhead target 51 (the road surface is relatively high) to the girder of the portion of the overhead target 51 through which the road passes, and the elevation angle θ _U are measured. Therefore, even though the height H _U from the vehicle horizontal central axis CL to the overhead target 51 can be obtained, the height H _T from the road surface 53 to the overhead target 51 cannot be obtained.

  In addition, the direction in which the laser beam is irradiated also changes due to the pitching of the vehicle (rotational movement about the horizontal direction in the left and right directions). The distance from the lower end of the mark to the road surface could not be obtained. In addition to changes in vehicle attitude, even when the road gradient is changing, the distance from the lower end of the target to the road surface can be obtained even if the distance and angle from the lower end of the target above the front are known. There wasn't.

  The present invention has been made to solve the above-described problem, and can determine the distance from a target existing above the road surface to the road surface regardless of changes in the state of the road or the posture of the vehicle. An object is to provide an upper obstacle detection device, a collision prevention device, and an upper obstacle detection method.

  In the upper obstacle detection device according to the first aspect of the present invention made to achieve the above object, the overhead target detection means emits a laser beam toward the upper front of the vehicle and scans in the vehicle width direction. Then, the laser beam applied to the overhead target is reflected and returned to the overhead target detecting means. The overhead target detection means detects (measures) a first time from when the laser light is emitted until it returns and an elevation angle that is an emission angle when the laser light is emitted from the overhead target detection means. .

The first time and the elevation angle detected by the overhead target detection means are used by the overhead target calculation means to calculate the overhead target distance and the overhead target height.
On the other hand, the road surface detection means emits laser light toward the road surface, scans in the vehicle width direction, and detects a second time until the laser light is reflected by the road surface and returns to the road surface detection means. At the same time, a depression angle that is an emission angle when the laser beam is emitted is detected. The second time and the depression angle detected by the road surface detection means are used for calculation of the road surface height in the road surface height calculation unit.

  When the overhead object height and the road surface height are calculated, the road height width is calculated by adding the overhead object height and the road surface height in the road height width calculation means. Here, when the arrangement height of the overhead target detection means with respect to the road surface is the same as the arrangement height of the road surface detection means, a value obtained by directly adding the overhead target height and the road surface height is used as the road height width. . On the other hand, if the placement height of the overhead target detection means and the placement height of the road surface detection means are different, the placement height of both of them is compared to the sum of the overhead target height and the road surface height. The corrected value of the difference is used as the road height width.

  By calculating the road height width, which is the distance from the road surface to the overhead target in this way, the road height changes, the road gradient changes, or the vehicle posture changes (especially Even in the case of pitching), it is possible to know the road height width accurately.

  In the above-described configuration, the road surface height is continuously obtained by continuously changing the depression angle related to the laser beam, and the road height is determined using the road surface height related to the road surface below the overhead target. The width may be calculated.

  In this case, since the road surface height on the road surface below the overhead target can be directly calculated, an accurate road surface height width can be obtained. For example, even when the road surface height where the vehicle is present and the road surface height below the overhead target are different, the road surface height below the overhead target can be directly calculated, and an accurate road height width can be obtained. .

  In the above-described configuration, a plurality of road surface heights related to the discrete areas on the road surface are obtained by discretely changing the depression angles related to the laser light, and from among them, the area closest to the road surface below the overhead target is obtained. The road surface height width may be calculated using the road surface height.

In this case, as compared with the case of acquiring a continuously changing road surface height, the configuration relating to the emission of the laser beam can be simplified, and the control of the emission direction of the laser beam is facilitated.
In the above-described configuration, the scanning target of the laser beam can be selected from the road surface in front of the vehicle provided with the road surface detection means, and the road surface below, and only when an overhead target exists in front of the vehicle, The road height width may be calculated.

  In this case, when there is no overhead target above the front of the vehicle, the laser beam can be applied to the road surface below the road surface detection means, that is, the road surface below the vehicle. Information obtained by receiving the laser beam reflected from the road surface can be used for purposes other than the calculation of the road height width, for example, for grasping the road surface state.

  Furthermore, the upper obstacle detection device according to the first aspect of the present invention compares the height of the road with the height of the vehicle, whether the overhead target and the vehicle contact or collide, in other words, It may be determined whether the vehicle can pass under the overhead target.

In this case, the vehicle occupant can know in advance whether or not the vehicle can pass under the overhead target in front.
Further, the upper obstacle detection device according to the first aspect of the present invention is obtained by calculating the road surface distance and the road surface height related to the plurality of regions arranged in the vehicle axial direction on the road surface, and using the road surface gradient calculated from these values. The road surface height on the road surface below the overhead target may be calculated. The road surface gradient may be a road surface gradient related to a distance between a plurality of road surface distances, or may be a road surface gradient related to a distance outside the range of the plurality of road surface distances.

  In this case, even if the road surface height on the road surface below the overhead target is not directly obtained, the road surface height can be calculated based on the road surface gradient. In other words, even if the overhead target distance and the road surface distance are different, for example, because the road surface height where the vehicle is present and the road surface height below the overhead target are different, the depression angle related to the laser light is not changed. The road surface height on the road surface below the overhead target can be calculated, and the accurate road height width can be obtained.

  Furthermore, in the above configuration, whether or not the overhead target and the vehicle contact or collide based on the road surface gradient, the road height width, and the vehicle height, in other words, the vehicle is below the overhead target. It may be determined whether or not it can pass through.

  In this case, even if the road surface height on the road surface below the overhead target is not directly obtained, it is possible to accurately determine whether the overhead target and the vehicle collide or the like based on the slope of the road surface.

  Further, in the configuration including the determination means, when it is determined that the overhead target and the vehicle are in contact with each other, the time until the vehicle contacts with the overhead target may be calculated based on the overhead target and the vehicle speed.

In this case, the vehicle occupant can know the time until the vehicle contacts the overhead target.
Furthermore, in the upper obstacle detection device according to the first aspect of the present invention, the road surface detection means may be provided in the upper front part of the vehicle to increase the incident angle of the laser beam with respect to the road surface. The front upper part of the vehicle is, for example, the vicinity of the windshield inside the vehicle interior, and is additionally provided or integrated with the rearview mirror, or on the dashboard or in the dashboard, or the roof portion.

  In this case, it is possible to irradiate the road surface with a laser beam at a large incident angle as compared with the case where the road surface detecting means is provided in a bumper portion of a conventional vehicle. For this reason, the intensity of the laser beam reflected on the road surface and returning to the road surface detection means is increased, and the road surface height can be easily obtained.

  In the collision prevention apparatus according to the second aspect of the present invention made to achieve the above object, an alarm is given to a vehicle occupant when it is determined that the overhead target and the vehicle come into contact with each other or collide with each other. To emit.

In this case, it is possible to alert the vehicle occupant.
In the upper obstacle detection method according to the third aspect of the present invention made to achieve the above object, first, the distance to the overhead target (overhead target distance) along the vehicle horizontal central axis and the detection The height from the means to the overhead target (overhead target height) is acquired, and then the height from the road surface to the detection means (road surface height) is acquired.

  Then, the road surface height is acquired, for example, by summing the overhead target height and the road surface height. Finally, the road surface height is compared with the height of the vehicle provided with the detecting means, and the overhead target and the vehicle come into contact with each other. It is determined whether or not to do so.

  Thus, by calculating the road height width, which is the height from the road surface to the overhead target, when the road surface height changes, the road surface gradient changes, or the vehicle posture changes ( Even in the case of (especially pitching), the road height width can be accurately known.

In the upward obstacle detection method according to the third aspect of the present invention, it may be determined whether or not the vehicle can pass under the overhead target only when the overhead target is found.
In this case, when an overhead target is not found, the detection means can be used for other purposes, and information obtained by scanning with laser light can be used for other purposes.

  In the upper obstacle detection method according to the third aspect of the present invention, when an overhead target exists in one of a plurality of distance ranges in which the road surface height can be acquired by the detection means, The road surface height of the road surface corresponding to the range, in other words, the road surface height on the road surface below the overhead target may be obtained.

  In this case, since the road surface height on the road surface below the overhead target can be directly calculated, an accurate road surface height width can be obtained.

It is a block diagram explaining the structure of the collision prevention apparatus which concerns on the 1st Embodiment of this invention. It is a flowchart explaining the judgment method of the collision possibility in the collision prevention apparatus of FIG. It is a schematic diagram explaining the scan of the laser beam by the sensor part of FIG. It is a schematic diagram explaining calculation of the height from a road surface to an overhead target. It is a flowchart explaining the judgment method of the collision possibility in the collision prevention apparatus which concerns on the modification of the 1st Embodiment of this invention. It is a schematic diagram explaining calculation of the gradient of a road surface. It is a block diagram explaining the structure of the collision prevention apparatus which concerns on the 2nd Embodiment of this invention. It is a schematic diagram explaining the judgment method of the collision possibility in the collision prevention apparatus 1 of FIG. It is a schematic diagram for explaining switching of the depression angle theta _L of the laser beam L _L. It is a schematic view illustrating the change of the depression angle theta _L of the laser beam L _L. It is a flowchart explaining the control in the collision prevention apparatus which concerns on the 3rd Embodiment of this invention. It is a flowchart explaining the other control in a collision prevention apparatus. It is a schematic diagram explaining the scanning of the conventional laser beam.

[First Embodiment]
A collision prevention apparatus including an upper obstacle detection apparatus according to a first embodiment of the present invention will be described with reference to FIGS.

FIG. 1 is a block diagram for explaining the configuration of the collision prevention apparatus 1 according to the present embodiment, and FIG. 2 is a flowchart for explaining a method for determining the possibility of collision in the collision prevention apparatus 1 of FIG. FIG. 3 is a schematic diagram for explaining the scanning of the laser beam by the sensor unit 10 of FIG. 1, and FIG. 4 is a schematic diagram for explaining the calculation of the height from the road surface 53 to the overhead target 51.
<Overall configuration>
The collision prevention apparatus 1 according to the present embodiment is an apparatus that recognizes an overhead target 51 that is an object existing in front of the vehicle and determines whether the vehicle 52 can pass under the overhead target 51. .

Collision prevention device 1, as shown in FIG. 1, recognizes the existence of the overhead target object 51, apparatus (upward seeking road height width H _T is the height from the road of the road surface 53 to the overhead target object 51 An obstacle detection device), a collision determination processing unit (determination means) 20 that determines whether or not the overhead target 51 and the vehicle 52 collide, and a vehicle speed control device 30 that controls the speed of the vehicle. And a collision mitigation control device (alarm means) 40 that reduces the possibility of collision by issuing an alarm or the like.
<Sensor>
As shown in FIG. 1, the sensor unit 10 includes a light emitting unit (overhead target detection unit, road surface detection unit, detection unit) 11 that emits laser light, and a light receiving unit (overhead target detection) that detects reflected laser light. Means, road surface detection means, detection means) 12, overhead target detection section (overhead target detection means, detection means) 13, road surface detection section (road surface detection means, detection means) 14, and road height width calculation section (Overhead target calculation means, road surface height calculation means, road height width calculation means) 15.
<Light emitting part>
The light emitting unit 11 constitutes an overhead target detection unit together with the light receiving unit 12 and the overhead target detection unit 13, and also constitutes a road surface detection unit together with the light receiving unit 12 and the road surface detection unit 14.

The light emitting unit 11 generates laser light with a narrowed beam width and controls the emission direction of the laser light. Specifically, by repeating a scan in the horizontal direction (width direction of the vehicle 52: a direction perpendicular to the paper surface of FIG. 3) with a constant elevation angle or depression angle of the laser light while changing the elevation angle and depression angle, two-dimensional Real scan (scan). In the present embodiment, as shown in FIG. 3, the elevation angle θ _U of the laser beam L _U is changed in four stages for detection of the overhead target 51, and the depression angle θ _L of the laser beam L _L is detected for detecting the road surface. Can be changed in four stages.

Here, the elevation angle θ _U is an angle in the vertical direction (the vertical direction in FIG. 4) from the vehicle horizontal central axis CL to the emission direction of the laser light L _U that scans the overhead target 51, and the depression angle θ _L Is the angle in the vertical direction from the vehicle horizontal central axis CL to the emission direction of the laser beam L _L that scans the road surface 53.

The light emitting unit 11 scans the laser beam L _U at one elevation angle θ _U for detecting the overhead target 51, and then scans the laser beam L _L at one depression angle θ _L for detecting the road surface 53. . Thereafter, the laser beam L _U is scanned at another elevation angle θ _U different from the one elevation angle θ _U, and then the laser beam L _L is scanned at another depression angle θ _L. This operation is sequentially performed for four different elevation angles θ _U and depression angles θ _L.

At this time, the light emitting unit 11 outputs the timing at which the laser beams L _U and L _L are emitted to the overhead target detection unit 13 and the road surface detection unit 14, and the emitted laser beams L _U and L _L. and it outputs the value of the elevation angle theta _U and depression theta _L.

As a configuration of the light emitting unit 11 that realizes such two-dimensional scanning, a known configuration can be used and is not particularly limited.
In FIG. 3, the region surrounded by the dotted line in the overhead target 51 indicates the region irradiated with the laser beam L _U , and the region surrounded by the dotted line on the road surface 53 is irradiated with the laser beam L _L. Indicates the area.
<Light receiver>
The light receiving unit 12 detects laser light emitted from the light emitting unit 11 and reflected from a target (an overhead target 51, a road surface 53 of a road, or the like). Further, the light receiving unit 12 outputs the timing at which the laser light is detected to the overhead target detection unit 13 and the road surface detection unit 14.
<Overhead target detection unit>
Overhead target object detection unit 13, based on emission timing of the laser beam L _U obtained from the light emitting unit 11 and the detection timing of the laser beam L _U obtained from the light receiving unit 12, the laser beam L _U is emitted from the light emitting unit 11 Then, a first time T1, which is a time from the reflection by the overhead target 51 to the detection by the light receiving unit 12, is measured.

Further, when the overhead target detection unit 13 can acquire the detection timing of the laser light L _U from the light receiving unit 12 (that is, when the first time T1 can be measured), the laser detected by the light receiving unit 12 The value of the elevation angle θ _U related to the light L _U is detected in association with the first time T1.
<Road surface detection unit>
Road detecting section 14, based on the emission timing of the laser beam L _L obtained from the light emitting unit 11 and the detection timing of the laser beam L _L obtained from the light receiving unit 12, the laser beam L _L is emitted from the light emitting unit 11, a road The second time T2, which is the time from when the light is reflected by the road surface 53 and detected by the light receiving unit 12, is measured.

Further, when the detection timing of the laser beam L _L can be acquired from the light receiving unit 12 (that is, when the second time T2 can be measured), the road surface detection unit 14 detects the laser beam L detected by the light receiving unit 12. the value of the depression angle theta _L of _L, and detected in association with the second time T2.
<Road height width calculator>
The road height width calculation unit 15 is an overhead target calculation unit that calculates an overhead target height H _U , a road surface height calculation unit that calculates a road surface height H _L , and a road height width H _T. It is also a road height width calculating means for calculating.

That is, the road height width calculation unit 15 calculates the overhead target distance D _U and the overhead target height H _U based on the first time T1 and the elevation angle θ _U , and the second time T2 and the depression angle θ _L. calculating a road surface distance D _L, and the road surface height H _L based on, and is designed to calculate the road height width H _T based on the overhead thereof altitude of H _U and road height H _L.

Here, the overhead target distance D _U is the distance from the sensor unit 10 to the overhead target 51 along the vehicle horizontal central axis CL, and the road surface distance D _L is from the sensor unit 10 to the vehicle. It is the distance to the road surface 53 along the horizontal center axis CL. FIG. 4 shows a case where the overhead target distance D _U is equal to the road surface distance D _L.

Road height width calculating section 15 calculates a first distance R _U from the speed of the first time T1 and the laser beam (speed of light) from the sensor unit 10 to the overhead target object 51, the second time T2 and laser A second distance _RL from the sensor unit 10 to the road surface 53 is calculated from the speed of light.

Then, the road height width calculation unit 15 calculates the overhead target distance D _U based on the following formula (1), and calculates the overhead target height H _U based on the formula (2). Similarly, the road surface distance D _L is calculated based on the equation (3), and the road surface height H _L is calculated based on the equation (4).

H _U = R _U · sinθ _U (1)
D _U = R _U · cos θ _U (2)
H _L = R _L · sinθ _L (3)
D _L = R _L · cos θ _L (4)
Here, the first distance R _U, is the distance from the sensor unit 10 to the portion where the laser beam L _U has been irradiated in the overhead target object 51, the road surface from the second distance sensor unit 10 and the R _L 53 the laser beam L _L is the distance to the portion irradiated at.

Thereafter, when the overhead target distance D _U and the road surface distance D _L are equal (in the case shown in FIG. 4), the road height width calculation unit 15 calculates the value of the overhead target height H _U and the road surface height H _L. by summing the values for calculating the value of the road height width H _T.
<Collision determination processing section>
Collision determination unit 20, as shown in FIG. 4, the road based on the height width H _T and the vehicle height h, in determining determining means whether or not the vehicle 52 collides or contacts with the overhead product target 51 is there.

In the collision determination processing unit 20, the vehicle height h of the vehicle 52 including the collision determination processing unit 20 is stored in advance, and further, the vehicle 52 passes under the overhead target 51 without colliding or contacting. A necessary gap width W is stored. When the sum of the vehicle height h and the gap width W is less than or less than the value of the road height width H _T , the collision determination processing unit 20 does not collide or contact the overhead target 51, It is determined that passing through is possible. In other cases, it is determined that the vehicle 52 cannot pass through because the vehicle 52 collides with or comes into contact with the overhead target 51.
<Vehicle speed control device>
As shown in FIG. 1, the vehicle speed control device 30 controls the vehicle speed, which is the speed of the vehicle, based on the determination by the collision determination processing unit 20. For example, when the collision determination processing unit 20 determines that the vehicle 52 collides with the overhead target 51 or the like, the vehicle speed control device 30 decelerates the vehicle 52 by automatically operating the brake of the vehicle 52 or the like. It is.

Note that the collision prevention device 1 may or may not include the vehicle speed control device 30 as in the present embodiment, and is not particularly limited.
<Collision mitigation control device>
The collision mitigation control device 40 is a warning unit that issues a warning to the vehicle occupant when it is determined that the vehicle 52 collides with the overhead target 51, and even if the vehicle 52 collides with the overhead target 51, This will reduce the damage caused by the collision. Specifically, the vehicle 52 is prepared by preparing the airbag operation of the vehicle 52 or automatically operating a brake instead of the vehicle speed control device 30 when the vehicle speed control device 30 is not provided. To slow down.
<< Collision prevention judgment >>
Next, a control method in the collision prevention apparatus 1 of the present embodiment and a control method in the sensor unit 10 which is an upper obstacle detection apparatus will be described with reference to the flowchart of FIG. S1 to S4 in FIG. 2 are controls common to the sensor unit 10 and the collision prevention device 1, and S5 and subsequent steps are control of only the collision prevention device 1.

Sensor portion 10 of the collision prevention device 1, the laser beam L _U emitted at a predetermined elevation angle theta _U, by performing scanning in the vehicle width direction of the vehicle 52, overhead target object 51 present in front and above the vehicle 52 Is detected (overhead target detection step S1). When the overhead target 51 is not detected (in the case of NO), the control in the collision preventing apparatus 1 and the sensor unit 10 is ended.

On the other hand, when the overhead target 51 is detected (in the case of YES), the sensor unit 10 determines the distance and height to the overhead target 51 (overhead target height acquisition step S2). Specifically, overhead target object detection portion 13 of the sensor unit 10, the timing signals output from the light emitting unit 11 and the light receiving unit 12, and, on the basis of the signal elevation angle theta _U, the first time T1, Then, the elevation angle θ _U related to the laser light L _U detected by the light receiving unit 12 is detected.

The road height width calculation unit 15 calculates the first distance R _U from the first time T1, and then the first distance R _U and the elevation angle θ _U related to the laser light L _U detected by the light receiving unit 12. The overhead target height H _U and the overhead target distance D _U are calculated based on the above formulas (1) and (2).

Thereafter, the sensor unit 10 calculates the distance and height to the road surface 53 (road surface height acquisition step S3). Specifically, road surface detecting unit 14 of the sensor unit 10, the timing signals output from the light emitting unit 11 and the light receiving unit 12, and, on the basis of a signal depression theta _L, the second time T2, and the light-receiving The depression angle θ _L related to the laser beam L _L detected by the unit 12 is detected.

Road height width calculating unit 15, the second time T2 by calculating a second distance R _L, then the second distance R _L, depression angle theta _L of the laser beam L _L detected by the light receiving unit 12 The road surface height H _L and the road surface distance D _L are calculated based on the above equations (3) and (4).

When the overhead target height H _U and the road surface height H _L are calculated, the road height width calculation unit 15 calculates the vertical width (height) at the position of the overhead target 51 (calculation step S4). . Specifically, as shown in FIG. 4, the road height width calculation unit 15 adds the overhead target height H _U and the road surface height H _{L in} which the overhead target distance D _U and the road surface distance D _L are equal. calculating a road height width H _T Te.

On the other hand, when the vehicle horizontal center axis CL related to the overhead object height H _U and the vehicle horizontal center axis CL related to the road surface height H _L are different and the heights of the two differ, against the H _U and road height H _L and adding combined value, the vehicle horizontal central axis according to the overhead product altitude of H _U CL, and the vehicle horizontal center axis CL of the road surface height H _L of the height those obtained by correcting the value of the difference is used as the road height width H _T.

This is the control common to the sensor unit 10 and the collision prevention apparatus 1.
The value of the road height width H _T calculated in the sensor unit 10 is inputted to the collision determination unit 20, (decision step is determining whether not through the bottom takes place in the vehicle 52 is overhead target object 51 S5). Here, when it is determined that it is not possible to pass through (in the case of NO), the control of the collision preventing apparatus 1 is ended.

On the other hand, when it is determined that the vehicle cannot pass through (in the case of YES), it is determined whether or not the vehicle 52 may collide with or come into contact with the overhead target 51 (determination step). S6). When it is determined that the vehicle 52 and the overhead target 51 may collide, for example, the vehicle speed control device 30 automatically operates the brake or the like to decelerate the vehicle 52, or the collision mitigation control device 40 issues an alarm. To alert the crew. In addition, the collision mitigation control device 40 enters preparation for the operation of the airbag. As a result, damage can be reduced even when the vehicle 52 actually collides with an overhead target.
<Effect>
As described above, the collision prevention device 1 of the present embodiment, the road height width H _T is the distance from the road surface 53 on the basis of the overhead product altitude of H _U and road height H _L up overhead target object 51 Even if the road surface height H _L changes, the road surface gradient changes, or the posture of the vehicle 52 changes (especially pitching), the road height width H _T is accurately calculated. Can know.

Furthermore, since the road surface height H _L and the vehicle height h are compared to determine whether or not the overhead target 51 and the vehicle 52 collide, the vehicle 52 passes under the overhead target 51. It is possible to accurately determine whether or not

  On the other hand, since it is determined whether or not the vehicle 52 can pass under the overhead target 51 only when the overhead target 51 is found, light emission occurs when the overhead target 51 is not found. The part 11 and the light receiving part 12 can be used for other purposes. For example, information on the road surface 53 obtained by scanning the laser beam in the vehicle width direction can be used for other purposes related to the traveling of the vehicle 52.

  In the present embodiment, as illustrated in FIG. 4, the sensor unit 10 is applied to an example provided at the tip of the vehicle 52, for example, the bumper unit. It is desirable to arrange in the upper part 52R (see FIG. 3).

By disposing the sensor unit 10 on the vehicle front upper portion 52R of the vehicle 52, the incident angle of the laser light irradiated on the road surface 53 is increased. Therefore, compared with the case where the sensor unit 10 is provided at a position lower than the vehicle front upper part 52R such as a bumper unit of the vehicle 52, the intensity of the laser beam reflected by the road surface 53 and returning to the light receiving unit 12 is increased. The height H _L can be easily obtained.
[Modification of First Embodiment]
Next, a modification of the first embodiment of the present invention will be described with reference to FIGS.

  The basic configuration of the collision prevention apparatus including the upper obstacle according to this modification is the same as that of the first embodiment, but is different from the first embodiment in that the road surface gradient is calculated. Yes. Therefore, in the present modification, only the periphery of the road surface slope calculation will be described with reference to FIGS. 5 and 6, and description of other components and the like will be omitted.

FIG. 5 is a flowchart for explaining a collision possibility determination method in the collision preventing apparatus 1 according to this modification. FIG. 6 is a schematic diagram for explaining the calculation of the slope of the road surface.
<Overall configuration>
Similar to the first embodiment, the sensor unit 10 of the collision prevention apparatus 1 according to the present modification includes a light emitting unit 11, a light receiving unit 12, an overhead target detection unit 13, and a road surface detection unit 14. Yes. The sensor unit 10 includes a road height width calculation unit 15 that further calculates the gradient of the road surface 53 (see FIG. 1).
<Road height width calculator>
Similarly to the first embodiment, the road height width calculation unit 15 calculates the overhead target height H _U and the road surface height H _L, and the gradient of the road surface 53 (hereinafter referred to as “road surface gradient”). Notation.) Is calculated. The road height width calculation unit 15 is also a gradient calculation unit that calculates the road height width H _T based on the overhead target height H _U , the road surface height H _L, and the road surface gradient.
<< Collision prevention judgment >>
Next, a control method in the collision prevention apparatus 1 of the present modification and a control method in the sensor unit 10 that is the upper obstacle detection apparatus will be described with reference to the flowchart of FIG. In addition, about the same control content as 1st Embodiment, the same code | symbol is attached | subjected and the description is abbreviate | omitted.

  As shown in FIG. 5, the collision prevention apparatus 1 according to the present modification detects an overhead target 51 existing in front of the vehicle 52 (S1), and when the overhead target 51 is detected, the overhead target 51 is detected. The distance and height up to 51 are determined (S2).

  Thereafter, the sensor unit 10 of the collision prevention apparatus 1 calculates the change in the gradient of the road surface 53 (S11) and calculates the height of the road surface 53 and the like before calculating the distance and height to the road surface 53. (S3).

Specifically, road surface detecting unit 14 of the sensor unit 10, the timing signals output from the light emitting unit 11 and the light receiving unit 12, and, on the basis of a signal depression theta _L, a plurality of second time T2, In addition, a plurality of depression angles θ _L related to the laser light L _L detected by the light receiving unit 12 is detected.

The road height width calculation unit 15 calculates each second distance R _L from the plurality of second times T 2, and calculates the second distance R _L and the laser light L _L detected by the light receiving unit 12. A plurality of road surface heights H _L and road surface distances D _L are calculated based on the depression angle θ _L and the above-described equations (3) and (4). When the plurality of road surface heights H _L and the road surface distances D _L are calculated, the road height calculation unit 15, as shown in FIG. It is written as “road slope etc.”).

Incidentally, road gradient, etc., the laser beam L _L according to some depression theta _L, no more depression theta _L of the laser beam L _L detected by the second time T2, and the light receiving unit 12 is detected However, it is calculated based on the remaining second time T2 and the like.

When the overhead target height H _U , the road surface height H _L , the road surface gradient, and the like are calculated, the road height width calculation unit 15 calculates the vertical width at the position of the overhead target 51 (calculation step). S12). Specifically, when there is an overhead target height H _U and a road surface height H _{L in} which the overhead target distance D _U and the road surface distance D _L are equal, the road height width calculation unit 15 adds the both. calculating a road height width H _T in. On the other hand, when there is no overhead target height H _U and road surface height H _{L in} which the overhead target distance D _U and the road surface distance D _L are equal, based on the road surface height H _L and the road surface gradient, A road surface height H _L at a road surface distance D _L equal to the overhead target distance D _U is calculated. Then, to calculate the road height width H _T by summing the road height H _L and overhead product altitude of H _U that the calculated.

Since the subsequent control is the same as in the first embodiment, the description thereof is omitted.
<Effect>
As described above, in the collision prevention apparatus 1 of the present modification, even if the road surface height _HL on the road surface 53 below the overhead target 51 is not directly obtained, the road surface height _HL is based on the road surface gradient or the like. Can be calculated. That is, for reasons of road height H _L and overhead target object 51 beneath the road surface height H _L are different such that the vehicle 52 is present, even when the overhead target object distance D _U and the road distance D _L is different , without changing the depression angle theta _L of the laser beam L _L, can be calculated road surface height H _L in overhead target object 51 under the road surface, it is possible to obtain an accurate road height width H _T.
[Second Embodiment]
Next, a second embodiment of the present invention will be described with reference to FIGS.

The basic configuration of the collision prevention apparatus including the upper obstacle according to the present embodiment is the same as that of the first embodiment, but the first embodiment is configured to switch the depression angle θ _L related to the laser light L _L. Is different. Therefore, in this modification, only the described peripheral configuration and control switching between the depression angle theta _L using 7 to 9, description of other components will be omitted.

FIG. 7 is a block diagram illustrating the configuration of the collision prevention apparatus 101 according to the present embodiment. FIG. 8 is a schematic diagram for explaining a method of determining the possibility of collision in the collision preventing apparatus 1 of FIG. FIG. 9 is a schematic diagram for explaining switching of the depression angle θ _L in the laser light L _L.
<Overall configuration>
As shown in FIG. 7, the collision prevention apparatus 101 includes a sensor unit 110 that is an upper obstacle detection apparatus, a collision determination processing unit 20 that determines whether or not the overhead target 51 and the vehicle 52 collide, and a vehicle The vehicle speed control device 30 that controls the speed of the vehicle and the collision mitigation control device 40 that reduces the possibility of collision by issuing an alarm or the like are mainly provided.
<Sensor>
As shown in FIG. 7, the sensor unit 110 includes a light emitting unit 11 that emits laser light, a light receiving unit 12 that detects reflected laser light, an overhead target detection unit 13, a road surface detection unit 14, a road height A width calculation unit 15 and a detection range switching unit (switching unit) 116 are mainly provided.
<Detection range switching unit>
As shown in FIG. 9, the detection range switching unit 116 switches the depression angle θ _L so that the area irradiated with the laser light L _L is a short-distance area AN near the vehicle 52 on the road surface 53 and a long distance far from the vehicle 52. Switching means for switching to the area AF. The light-emitting unit 11 in the present embodiment is capable of irradiating laser beam L _L to select one of the short range AN and long range AF.

The detection range switching unit 116 receives the overhead target distance D _U calculated from the road height width calculation unit 15 and switches the irradiation region of the laser light L _L from the detection range switching unit 116 to the light emitting unit 11. A control signal is output.
<< Collision prevention judgment >>
Next, a control method in the collision prevention apparatus 101 according to the present embodiment and a control method in the sensor unit 110 that is the upper obstacle detection apparatus will be described with reference to the flowchart of FIG. In addition, about the same control content as 1st Embodiment, the same code | symbol is attached | subjected and the description is abbreviate | omitted.

  As shown in FIG. 8, the collision prevention apparatus 101 according to the present embodiment detects an overhead target 51 existing in front of the vehicle 52 (S1), and when the overhead target 51 is detected, the overhead target 51 is detected. The distance and height up to 51 are determined (S2).

Thereafter, before calculating the distance to the road surface 53 and the height, the detection range switching unit 116 determines whether or not the overhead target distance D _U is within the road surface detection range in the sensor unit 110 (comparison step S21). ). For example, in the case where the laser beam L _L is irradiated to the near zone the AN, the distance range along the vehicle horizontal central axis CL in the close area AN, by comparing the overhead target object distance D _U, overhead It is determined whether or not the target distance D _U is longer than the distance range.

If overhead target object distance D _U is within the distance range, in a state of irradiating a laser beam L _L to close area AN, and calculates the height of the road surface or the like 53 (S3). Since the subsequent control is the same as in the first embodiment, the description thereof is omitted.

On the other hand, if the overhead target object distance D _U is farther than the distance range, for example, when included in the distance range along the vehicle horizontal central axis CL in the far area AF in the detection range switching unit 116, outputs a control signal for changing the depression angle theta _L of the laser beam L _L, it is irradiated with the laser beam L _L in the far area AF of the road surface 53 (changing step S22). Then, the height of the road surface 53 and the like are calculated in a state where the long-distance area AF is irradiated with laser light (S3). Since the subsequent control is the same as in the first embodiment, the description thereof is omitted.
<Effect>
As described above, in the collision prevention apparatus 101 of this embodiment, when the overhead target 51 exists in one of the short-distance area AN or the long-distance area AF, the road surface of the road surface 53 corresponding to the one area. The height H _L , in other words, the road surface height H _L on the road surface 53 below the overhead target 51 may be obtained. In this case, since it is possible to directly calculate the road surface height H _L in the road surface below the overhead target object 51, it is possible to obtain an accurate road height width H _T.

Further, the configuration of the light emitting unit 11 is simplified and the emission direction of the laser light L _L can be easily controlled as compared with the case where the depression angle θ _L is continuously changed and the laser light L _L is irradiated.
FIG. 10 is a schematic diagram for explaining the change of the depression angle θ _L in the laser light L _L.

In the above-described embodiment, the depression angle θ _L related to the laser light L _L is discretely changed and applied to a configuration in which one of the short-distance area AN and the long-distance area AF is selected. as shown in, by changing the depression angle theta _L continuously, then change the area where the laser beam L _L is irradiated continuously, there is no particular limitation.

In this way, continuously compared with a configuration for selecting one of the short range AN and far-field AF described above, the area to be irradiated with laser light L _L in order to calculate the road surface height H _L Can be changed and adjusted. Therefore, the range in which the road surface height H _L on the road surface 53 below the overhead target 51 can be directly calculated is widened. For example, even when the road surface height where the vehicle 52 exists and the road surface height H _L below the overhead target 51 are different, the road surface height H _L below the overhead target 51 can be directly calculated, and the accurate road height The width is easy to find.
[Third Embodiment]
Next, a third embodiment of the present invention will be described with reference to FIG. 11 and FIG.

  The basic configuration of the collision prevention apparatus including the upper obstacle according to this modification is the same as that of the modification of the first embodiment, but the modification of the first embodiment is a control for preventing a collision or the like. The difference is that the vehicle speed is also taken into account. Therefore, in this embodiment, only the periphery of the control for preventing a collision or the like will be described with reference to FIGS. 11 and 12, and description of other components will be omitted.

FIG. 11 is a flowchart illustrating control in the collision preventing apparatus 1 according to the present embodiment.
<< Collision prevention judgment >>
A control method in the collision preventing apparatus 1 of the present embodiment will be described with reference to the flowchart of FIG. In addition, since the control method in the sensor part 10 which is an upper obstacle detection apparatus of this embodiment is the same as that of the modification of 1st Embodiment, the description is abbreviate | omitted.

The value of the road height width H _T calculated in S12 is input to the collision determination unit 20, the vehicle 52 it is determined whether not pass through the bottom of the overhead target object 51 is performed (S5). Here, the collision determination processing unit 20 acquires the vehicle speed that is the traveling speed of the vehicle 52 (S31). Various means such as a vehicle speed sensor can be used as the vehicle speed acquisition means for acquiring the vehicle speed, and is not particularly limited. The vehicle speed signal output from the vehicle speed acquisition unit is input to the collision determination processing unit 20 which is also a time calculation unit that calculates the time until the overhead target 51 and the vehicle 52 collide.

Collision determination unit 20, together with the overhead target object 51 and the vehicle 52 calculates the time to collision or the like based on the vehicle speed signal and overhead target object distance D _U described above, the vehicle 52 is an overhead target object 51 collides Alternatively, it is determined whether or not there is a possibility of contact (determination step S32).

If it is determined that there is a possibility that the vehicle 52 and the overhead target 51 may collide, the warning is given to the passenger of the vehicle 52 to alert the passenger of the time until the collision mitigation control device 40 collides. The vehicle speed control device 30 automatically operates a brake or the like according to the vehicle speed or the time until a collision, etc., and decelerates the vehicle 52.
<Effect>
As described above, in the collision prevention apparatus 1 according to the present embodiment, the time until the vehicle collides with an overhead target is calculated, and an alarm is issued based on the calculated time. You can know the time to the overhead target and the collision. Furthermore, the vehicle 52 can be decelerated in accordance with the vehicle speed, the time until the collision, etc., so that the collision can be avoided or the damage such as the collision can be reduced.

FIG. 12 is a flowchart for explaining another control in the collision preventing apparatus.
As in the above-described embodiment, control for preventing a collision or the like may be performed in consideration of the vehicle speed in the modification of the first embodiment, or in the second embodiment as shown in FIG. Control for preventing a collision or the like in consideration of the vehicle speed may be performed, and is not particularly limited.

  The control content in FIG. 12 is the same as the control in the second embodiment and the third embodiment, so FIG. 12 is shown and description thereof is omitted.

1,101 ... collision prevention device 51 ... overhead target object 52 ... vehicle 10,110 ... sensor unit 20 ... collision determination unit (determination means) 40 ... collision mitigation control unit (alarm means) H _T ... road Height Width 11 ... Light emitting part (overhead target detection means, road surface detection means, detection means) 12 ... Light receiving part (overhead target detection means, road surface detection means, detection means) 13 ... Overhead target detection part (overhead target detection means, detection means) 14 ... Road surface detection unit (road surface detection means, detection means) 15 ... Road height width calculation unit (overhead target calculation means, road surface height calculation means, road height width calculation means) θ _U ... elevation angle θ _L ... depression angle T1 ... first time T2 ... second time D _U ... overhead target object distance H _U ... overhead product elevation of D _L ... road distance H _L ... road height H _T ... road height width

Claims (13)

A laser beam is scanned in the vehicle width direction with respect to the overhead target, a first time from when the laser beam is emitted, reflected by the overhead target, and returned, and from the vehicle horizontal central axis, An overhead target detection means for detecting an elevation angle which is an angle to the emission direction;
Based on the first time and the elevation angle, an overhead target distance that is a distance from the overhead target detection means to the overhead target along the vehicle horizontal central axis, and from the overhead target measurement means An overhead target calculating means for calculating an overhead target height which is a height to the overhead target;
The laser beam is scanned in the vehicle width direction with respect to the road surface, and the laser beam is emitted from the vehicle horizontal center axis along with a second time until the laser beam is emitted and reflected by the road surface. Road surface detecting means for detecting a depression angle that is an angle to the direction;
Based on the second time and the depression angle, a road surface distance that is a distance from the road surface detection unit to the road surface along the vehicle horizontal central axis, and a road surface that is a height from the road surface to the road surface detection unit Road surface height calculating means for calculating the height;
A road height width calculating means for calculating a road height width that is a height from the road surface to the overhead target based on the overhead object height and the road surface height;
An upper obstacle detection device comprising: The road surface detecting means continuously changes the depression angle and scans the laser light in the vehicle width direction,
The road surface height calculating means calculates the road surface distance and the road surface height for each depression angle that continuously changes,
The road height width calculating means calculates the road height width using the road surface height corresponding to the road surface distance equal to the overhead target distance among the plurality of road surface distances. The upper obstacle detection apparatus according to claim 1. The road surface detecting means discretely changes the depression angle and scans the laser light in the vehicle width direction,
The road surface height calculating means calculates the road surface distance and the road surface height for each different depression angle,
The road height width calculating means calculates the road height width using the road surface height corresponding to the road surface distance closest to the overhead target distance among the plurality of road surface distances. The upper obstacle detection device according to claim 1. The road surface detection means is capable of scanning the laser light in the vehicle width direction with respect to the road surface in front of the road surface detection means and the road surface below the road surface detection means,
Switching means for scanning the laser light in the vehicle width direction with respect to the road surface ahead of the road surface detection means when the laser light reflected from the overhead target is detected by the overhead target detection means. Further,
2. The upper obstacle detection device according to claim 1, wherein the road height width calculating means calculates the road height width using a road surface height relating to the road surface ahead of the road surface detecting means.   The apparatus further comprises a determination unit that compares the height of the road and the height of a vehicle stored in advance to determine whether the overhead target and the vehicle are in contact with each other. The upper obstacle detection device according to any one of 1 to 4. The road surface detection means changes the depression angle and scans the laser light in the vehicle width direction,
The road surface height calculating means calculates a plurality of the road surface distances corresponding to different depression angles, and a plurality of the road surface heights,
A slope calculating means for calculating a slope of the road surface based on the plurality of road surface distances and the plurality of road surface heights;
The road height width calculating means calculates the road surface height at the overhead target distance using the road surface gradient, and calculates the road height width using the calculated road surface height. The upper obstacle detection device according to claim 1, wherein   Comparing the slope of the road surface, the height of the road, and the height of the vehicle stored in advance, it further comprises a judging means for judging whether or not the overhead target is in contact with the vehicle. The upper obstacle detection device according to claim 6, wherein Vehicle speed acquisition means for acquiring a vehicle speed that is the traveling speed of the vehicle;
Based on the vehicle speed and the overhead target distance, time calculation means for calculating a time until the overhead target and the vehicle come into contact with each other;
The upper obstacle detection device according to claim 5 or 7, further comprising:   The upper obstacle detection device according to any one of claims 1 to 8, wherein the road surface detection means is provided at a position where a depression angle can be obtained within a range of 0 to 90 degrees. An upper obstacle detection device according to any one of claims 5, 7, and 8,
An alarm means for issuing an alarm when it is determined by the determining means that the overhead target and the vehicle are in contact;
An anti-collision device comprising: An overhead target distance, which is a distance from a detection means for detecting an overhead target and a road surface by scanning a laser beam to the overhead target along a vehicle horizontal central axis, and an overhead target from the detection means. An overhead object height acquisition step of acquiring an overhead object height which is a height of up to,
A road surface height obtaining step for obtaining a road surface height which is a height from the road surface to the detection means;
A calculation step of calculating a road height width that is a height from the road surface to the overhead target based on the overhead target height and the road surface height;
A determination step of comparing the height of the road surface and the height of the vehicle stored in advance and determining whether or not the overhead target is in contact with the vehicle;
An upper obstacle detection method comprising: Before acquiring the overhead target distance and the overhead target height,
A step of detecting an overhead target by scanning a laser beam toward the upper front of the detection means and detecting the presence or absence of the overhead target;
12. The upper obstacle detection method according to claim 11, wherein when the overhead target is detected in the overhead target detection step, the steps after the target height acquisition step are performed. After acquisition of the overhead target distance and before acquisition of the road surface height,
A comparison step of comparing the overhead target distance and a plurality of distance ranges capable of acquiring the road surface height in the detection means;
When the overhead target distance is within one of the plurality of distance ranges, a change step of changing the laser light scan region to the road surface corresponding to the one range;
The upper obstacle detection method according to claim 11 or 12, further comprising:

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