JPH06289138A - Obstacle detecting device - Google Patents

Abstract

PURPOSE:To provide an obstacle detecting device which can detect only an obstacle which interferes with traveling. CONSTITUTION:An obstacle detecting device has a measuring part 3, which measures the time in which a light receiving part 2 receives the reflection light. In a control part 5, the measured time and the threshold time which is previously memorized in the second memory 11 are compared. If the measured time is longer, a detection permission signal is outputted into a distance detection part 4, and the distance data from the obstacle which is detected by the distance detection part 4 is outputted into an alarm lamp 9 and a display unit 10. Accordingly, only the obstacle which interferes with traveling can be detected, and only the information necessary for a driver can be obtained, and the safety during drive can be improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an obstacle detection device mounted on a vehicle for detecting an obstacle in front of the vehicle in the traveling direction and, if necessary, a distance to the obstacle. .

[0002]

2. Description of the Related Art Conventionally, an obstacle for detecting a front vehicle in order to prevent a collision accident or a rear-end collision with an obstacle ahead, especially a vehicle traveling in the front (hereinafter referred to as "front vehicle"). Object detection devices are known. An example of such an obstacle detection device is disclosed in, for example, Japanese Patent Laid-Open No. 62-145178.
It is disclosed in the publication. According to this publication, the obstacle detection device has a light emitting unit, and the sensor beam is emitted from the light emitting unit in the forward direction of the vehicle. This sensor beam is scanned up and down at a predetermined angle in order to reliably detect an obstacle ahead.

In the obstacle detecting device, when there is an obstacle ahead, the sensor beam is reflected by the obstacle and the reflected light is received. Then, the presence of the obstacle is detected based on the received reflected light, and the driver is notified of the presence of the obstacle. Based on this notification, the driver recognizes that there is an obstacle ahead,
I took appropriate measures to avoid collision accidents.

[0004]

Since the obstacle detecting device detects an obstacle in front of it in order to prevent a collision accident or the like, it is essential to detect only an obstacle which originally impedes traveling. The purpose is achieved. However, in the above-mentioned obstacle detection device, since the sensor beam is scanned up and down, not only obstacles such as a forward vehicle that hinders traveling to be detected, but also rolling on a road that does not hinder traveling. Even pebbles and empty bottles may be detected.

More specifically, as shown in FIG. 8, assuming that the scanning angle of the sensor beam is θ, the sensor beam is scanned within the scanning angle θ, so that most obstacles within the scanning angle θ are present. Reflected by objects. That is, the sensor beam is reflected not only by the forward vehicle PM within this scanning angle θ but also by the pebbles KS. However, in the obstacle detection device, the reflected light is reflected in the forward vehicle PM to be detected.
It does not have the function of discriminating whether the light is reflected by or the light reflected by the pebbles KS. Therefore, even when the sensor beam is reflected by the pebbles KS, the obstacle detection device detects the presence of the obstacle based on the reflected light.

When the obstacle detecting device detects an obstacle, the driver is informed of the existence of the obstacle in order to inform the driver. However, even if the presence of pebbles or the like that does not hinder the running is notified, the driver has almost nothing to do to avoid the accident, and there is no merit to the driver. Further, since pebbles and the like often roll on the road, the driver is frequently notified. However, if the driver is informed too often, the driver may be used to the notification, which may reduce the effectiveness of obstacle detection.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above technical problems and to provide an obstacle detecting device capable of detecting only obstacles which hinder traveling.

[0008]

An obstacle detecting device according to claim 1 for achieving the above object is mounted on a vehicle.
An obstacle detection device that emits light forward in the traveling direction of the vehicle and, when there is an obstacle in the forward traveling direction of the vehicle, receives light reflected by the obstacle by a light receiving means to detect the presence of the obstacle. The measuring means for measuring the time during which the light receiving means receives the reflected light, and the time measured by the measuring means are compared with a predetermined time, and as a result of the comparison, the measurement is performed. And an obstacle detection signal output means for outputting an obstacle detection signal when the time is longer than a predetermined time.

Further, the obstacle detecting device according to the second aspect is
The obstacle detecting apparatus according to claim 1, wherein the obstacle detecting apparatus includes a distance measuring unit that measures a distance to the detected obstacle. Further, the obstacle detecting device according to claim 3 is the obstacle detecting device according to claim 2, wherein the distance measuring means receives a light reception start time from the irradiation start time to when the light receiving means starts receiving the reflected light. It is characterized in that the distance is measured on the basis of the time difference up to.

Further, the obstacle detecting device according to claim 4 is
The obstacle detection device according to claim 2, wherein the distance measuring means measures the distance based on a difference in the light receiving position of the reflected light received by the light receiving means. .

[0011]

In the structure according to the first aspect, the time during which the light receiving means receives the reflected light is measured by the measuring means, and the measured time is compared with the predetermined time. As a result, when the measured time is longer than the predetermined time, the obstacle detection signal output means outputs the obstacle detection signal.

The time when the reflected light is received by the light receiving means is approximately proportional to the height of the obstacle from the road. Therefore, if the time during which the reflected light is received is long, it can be determined that the obstacle is an obstacle having a certain height, for example, a vehicle, and therefore only the obstacle that interferes with traveling can be detected. . Further, in the configuration according to claim 2, since the distance to the detected obstacle is measured by the distance measuring means,
Not only the existence of the obstacle but also the distance information to the obstacle can be obtained, and the fact that the obstacle is too close can be notified.

Further, in the third aspect of the invention, the distance to the detected obstacle is detected based on the time difference from the irradiation start time to the light reception start time, so that the distance to the obstacle can be reliably measured. can do. Further, in the configuration according to claim 4, since the distance to the detected obstacle is measured based on the difference in the light receiving position of the reflected light, the distance to the obstacle can be reliably measured.

[0014]

Embodiments of the present invention will be described in detail below with reference to the accompanying drawings. FIG. 1 is a block diagram showing a simplified configuration of an obstacle detection device according to an embodiment of the present invention. This obstacle detection device is mounted on a vehicle and is used to detect the presence of an obstacle and the distance to the obstacle based on the reflected light from the obstacle ahead. This obstacle detection device includes a light emitting unit 1 that emits a sensor beam forward of a vehicle, a light receiving unit 2 that receives light reflected by an obstacle, and a time when the light receiving unit 2 receives the reflected light. The measuring unit 3 for measuring the distance, the distance detecting unit 4 for detecting the distance to the obstacle based on the reflected light received by the light receiving unit 2, and the control unit 5 for controlling each unit.

More specifically, the light emitting section 1 includes an infrared light emitting diode, a laser diode and the like. A control unit 5 is connected to the light emitting unit 1, and a sensor beam is emitted at predetermined intervals based on a control signal from the control unit 5. A movable portion 1a for moving the light emitting portion 1 is mechanically connected to the light emitting portion 1. The movable portion 1a moves the light emitting portion 1 up and down at a predetermined angle with respect to the traveling direction of the vehicle based on a control signal given from the control portion 5. Therefore, the sensor beam emitted from the light emitting unit 1 is emitted while being vertically scanned at a predetermined angle.

The light receiving section 2 includes a phototransistor, a photodiode and the like. The light receiving unit 2 is a measuring unit 3
And the distance detection unit 4. The light receiving unit 2 outputs a high level signal while the reflected light is being received, and outputs a low level signal during the other periods. The measuring unit 3 measures the time during which the high-level signal output from the light receiving unit 2 is output, and the measured light receiving time is given to the control unit 5.

The distance detector 4 has a time difference calculator 6 and a distance calculator 7. The time difference calculation unit 6 calculates the time difference between the time when the sensor beam is emitted from the light emitting unit 1 and the time when the light reflected by the obstacle is received by the light receiving unit 2. The time data when the sensor beam starts to be emitted is given from the control unit 5. A first memory 8 is connected to the distance calculation unit 7. The first memory 8 stores the time difference between the irradiation start time and the light reception start time and the distance data in association with each other. In the distance calculation unit 7, this first
With reference to the memory 8, the distance data corresponding to the time difference calculated by the time difference calculation unit 6 is checked.

A second memory 11 is connected to the control unit 5. In this second memory 11, a threshold time (hereinafter, simply referred to as “threshold time”) is stored in advance. This threshold time is a time that is set in advance so that it is possible to distinguish an obstacle that does not hinder traveling from an obstacle that does not hinder traveling on the threshold time. However, this threshold time can be changed later.

The control unit 5 determines whether or not the reflected light received by the light receiving unit 2 is light reflected by an obstacle that impedes traveling, based on the light receiving time measured by the measuring unit 3. . That is, in the control unit 5, when the light reception time measured by the measurement unit 3 is longer than the threshold time stored in the second memory 11, the obstacle reflected by the reflected light is an obstacle that hinders traveling. It is determined that there is an obstacle, and if it is short, the obstacle reflected by the reflected light is determined to be an obstacle that does not hinder traveling. Then, when it is determined that the obstacle is an obstacle that hinders traveling, a detection permission signal is output to the distance calculation unit 8. In the distance calculation unit 8, when the detection permission signal is given, the distance data is output to the alarm lamp and the display unit 10. On the other hand, if it is determined that the obstacle is an obstacle that does not hinder traveling, the distance calculation unit 8
The detection permission signal is not output to and the distance data is not output.

FIG. 2 is a side view of the attachment state of the obstacle detection device. The obstacle detection device is attached, for example, below the inner surface of the windshield FG on the driver's side. Further, the obstacle detection device may be mounted above the inner surface of the windshield FG, or may be mounted on an instrument panel inside the vehicle. From this obstacle detection device, the sensor beam is emitted while being scanned vertically at a predetermined angle θ toward the front in the traveling direction of the vehicle.

FIG. 3 is a schematic view showing the irradiation state of the sensor beam emitted from the obstacle detecting device. The sensor beam is emitted from the obstacle detection device while being vertically scanned at a scanning angle θ, and when the forward traveling vehicle PM and the pebbles KS are within the range of the scanning angle θ, the sensor beam is the forward traveling vehicle PM. And reflected by pebbles KS. At this time, the angles at which the sensor beam is applied to the front traveling vehicle PM and the pebbles KS are θ2 and θ1, respectively.

FIG. 4 is a diagram showing FIG. 3 as a simpler model. In this figure, L2 indicates the height of the forward traveling vehicle PM with respect to the road, and L1 indicates the height of the pebbles KS with respect to the road. From this figure, the irradiation angle θ1 of the pebbles KS is included in the irradiation angle θ2 of the forward traveling vehicle PM, and the irradiation angle θ2 is larger than the irradiation angle θ1. That is, since the sensor beam is emitted to the forward traveling vehicle PM longer than the pebbles KS, the light receiving time during which the light receiving unit 2 receives the reflected light is longer in the forward traveling vehicle PM than the pebbles KS. Become.
Therefore, if the threshold time is set to an appropriate value between the light reception times of the preceding traveling vehicle PM and the pebbles KS, and this threshold time is compared with the actual light reception time, it is determined whether the obstacle is an obstacle to traveling. Can judge.

Further, when the vehicle equipped with the obstacle detection device is also traveling, and the forward obstacle PM is also traveling in the same direction, the irradiation angle θ with respect to the forward traveling vehicle PM.
2 becomes larger than the irradiation angle θ1 with respect to the pebbles KS. That is, the difference in the light receiving time of the reflected light becomes more remarkable, and it becomes easier to determine whether or not the obstacle is an obstacle that hinders traveling.

On the other hand, when the front obstacle PM is traveling in the opposite direction to the vehicle, the irradiation angle θ2 is narrower than when traveling in the same direction, but the irradiation angle θ of the pebbles KS is smaller.
Since it is still larger than 1, there is no problem in practical use. Figure 5
3 is a flowchart showing an operation of the obstacle detection device shown in FIG. 1. To explain along the flow of FIG. 5 with reference to FIG. 1, when a control signal is output from the control unit 5 to the movable unit 1a and the light emitting unit 1, the light emitting unit 1 emits a sensor beam (step S1). At the same time, the light emitting unit 1 is vertically moved by the movable unit 1a (step S2), and the sensor beam is vertically scanned at a predetermined scanning angle θ. When the sensor beam is reflected by an obstacle and the reflected light is received by the light receiving unit 2 (step S3), a signal corresponding to the received reflected light is given to the time difference calculating unit 6 and the light emitting unit 1
From, the time difference between the time when the sensor beam starts to emit and the time when the reflected light starts to be received is calculated (step S
4). Then, the distance calculator 7 refers to the first memory 8 to calculate the distance to the obstacle (step S5).

On the other hand, the signal corresponding to the reflected light received by the light receiving section 2 is also given to the measuring section 3 and the time during which the light receiving section 2 receives the reflected light is measured (step S6). Then, the measured light reception time is given to the control unit 5.
In the control unit 5, the predetermined threshold time stored in the second memory 11 is compared with the measured time (step S7), and if the measured time is longer as a result, it is calculated in step S5. The distance data thus obtained is given to the alarm lamp 9 and the display unit 10 (step S).
8). On the other hand, if the threshold time is longer, it is considered that the reflected light is reflected by an obstacle that does not hinder traveling, and the distance data calculated in step S5 is not output (step S9).

As described above, according to the obstacle detecting apparatus of the present embodiment, the light receiving time of the light reflected by the obstacle ahead is measured by the measuring unit 3, and when the light receiving time is longer than the threshold time. Since the distance data detected by the distance detection unit 4 is output only to the vehicle, only obstacles that hinder traveling can be detected. Therefore, it is possible to provide the driver with the existence information of the obstacle that is really necessary.

Further, since the distance to an obstacle that interferes with running is detected, if the distance to the obstacle becomes shorter than a predetermined safety distance, the driver can be notified of that fact by an alarm or the like, and the driving can be performed. The safety inside can be increased. Also, the driver can be provided with only the truly necessary distance information. Although the description of the present embodiment is as described above, the present invention is not limited to the above embodiment. For example,
In the above-described embodiment, when an obstacle that hinders traveling is detected, the distance to the obstacle is detected. However, the distance is not detected, and only the existence of the obstacle that hinders traveling is detected. May be detected.

In the above embodiment, the distance to the obstacle is calculated based on the time difference between the light emission start time of the sensor beam and the light reception start time of the reflected light. The distance may be calculated by using the so-called triangulation method, which calculates the distance to the obstacle based on the difference between. Hereinafter, this modification will be described with reference to FIGS. 6 and 7.

FIG. 6 is a block diagram simply showing the structure of the obstacle detecting device of this modification. This obstacle detection device includes a light receiving unit 30, a light receiving position identifying unit 31 that identifies the position where the reflected light is received, and a memory 32 that stores distance data corresponding to each light receiving position in advance. It has a section 34. Other configurations are the same as those in the above embodiment.

FIG. 7 is a schematic view showing in detail the structure of the light receiving section 30. The light receiving unit 30 includes an optical system 40 that changes the optical path of reflected light and a light receiving element array 41 that receives the reflected light whose optical path is changed by the optical system 40. The optical system 40 includes a reflecting mirror 40a and a light entering lens 40.
The light having the angle b, which is reflected by the obstacle, reaches the reflecting mirror 40a, is reflected by the reflecting mirror 40a, its direction is changed, and forms an image on the light receiving element array 41 through the light entering lens 40b. To be done.

The light receiving element array 41 comprises a plurality of light receiving elements 4
11 to 41n. Each light receiving element 411-4
Since 1n is provided at a position corresponding to the distance to the obstacle based on the triangulation method, the distance to the obstacle can be obtained depending on which light receiving element receives the reflected light. More specifically, the reflecting mirror 40a guides the reflected light to the light receiving element 41n at one end when the light reflected by the obstacle 80m ahead enters. Further, the reflecting mirror 40a guides the reflected light to the light receiving element 411 at the other end when the light reflected by the obstacle 30 m ahead is incident. Further, the light reflected by the obstacle between 80 m and 30 m ahead is guided to any of the corresponding light receiving elements 411 to 41n according to the distance. Note that the reflected light is not necessarily guided to only one light receiving element, but there is no problem if it is determined which light receiving element is the center of which the reflected light is detected. In this way, the distance to the obstacle can be detected.

In the above embodiment, the case where the irradiation light is scanned vertically has been described, but the irradiation light may be irradiated at an angle of φ with respect to the road, for example. Moreover, you may irradiate several irradiation light with a fixed irradiation angle. In addition, various design changes can be made without changing the gist of the present invention.

[0033]

As described above, according to the obstacle detecting device of the first aspect, when the time during which the reflected light is received is longer than the predetermined time, the obstacle detecting signal is output. Therefore, it is possible to detect only obstacles that hinder driving. Therefore, only the truly necessary information can be obtained. In particular, when the obstacle detection device is mounted in the vehicle, it is not possible to irradiate the obstacle in front in parallel with the light in order to efficiently irradiate the obstacle, so that it is effective.

Further, according to the obstacle detecting device of the second aspect, since only the distance to the obstacle which hinders traveling is detected, the distance to the obstacle can be shorter than the predetermined distance. For example, it is possible to notify the driver of that fact by an alarm or the like and enhance the safety. Further, it is possible to give only the truly necessary distance information to the driver. Further, according to the obstacle detecting device of the third aspect, it is possible to reliably detect the distance.

Further, according to the obstacle detecting device of the fourth aspect, it is possible to reliably detect the distance.

[Brief description of drawings]

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

FIG. 2 is a side view of an attachment state of the obstacle detection device.

FIG. 3 is a schematic diagram showing an irradiation state of a sensor beam by an obstacle.

FIG. 4 is a diagram showing FIG. 3 as a simpler model.

FIG. 5 is a flowchart showing the operation of the obstacle detection device.

FIG. 6 is a block diagram showing a simplified configuration of an obstacle detection device according to a modification of the present invention.

FIG. 7 is a diagram showing the configuration of a light receiving unit in detail.

FIG. 8 is a diagram for explaining a defect of a conventional obstacle detection device.

[Explanation of symbols]

 1 Light emitting part 1a Movable part 2 Light receiving part 3 Measuring part 4 Distance detecting part 5 Control part

Claims (4)

[Claims] 1. An obstacle mounted on a vehicle, which irradiates light forward of a traveling direction of a vehicle, and when there is an obstacle ahead of the traveling direction of the vehicle, the light reflected by the obstacle is received by a light receiving means to obstruct the obstacle. In an obstacle detection device for detecting the presence of an object, the light receiving means compares the time during which the light receiving means receives the reflected light, and the time measured by the measuring means is compared with a predetermined time. An obstacle detection device comprising: an obstacle detection signal output means for outputting an obstacle detection signal when the measured time is longer than a predetermined time as a result of the comparison. 2. The obstacle detection device according to claim 1, wherein
The obstacle detecting device includes a distance measuring unit that measures a distance to the detected obstacle. 3. The obstacle detection device according to claim 2,
The obstacle detecting device is characterized in that the distance detecting means measures a distance based on a time difference from an irradiation start time to a light reception start time at which the light receiving means starts receiving reflected light. 4. The obstacle detection device according to claim 2,
The obstacle detecting device is characterized in that the distance detecting means measures the distance based on a difference in light receiving position of reflected light received by the light receiving means.