JPH07104066A - Obstacle detecting device for vehicle - Google Patents

Abstract

PURPOSE:To damp the reflected light on a road surface by providing a laser beam permeable cover member having a region with low permeability for a laser beam partially, e.g. at the lower section, in front of a laser radar device. CONSTITUTION:The laser beam 3 emitted from a laser radar device 1 mounted at the front section of a vehicle penetrates a cover member 2 and is reflected on an obstacle in front of the vehicle, and the reflected light penetrates the cover member 2 and is returned to the light reception section of the device 1. The cover member 2 is provided with an upper region 2a having high permeability for the laser beam 3 and a lower region 2b having low permeability. The laser beam 3 emitted from the device 1 and spread into a funnel shape is formed into an upper beam region 3a having high intensity and a lower beam region 3b having low intensity. The lower beam region 3b is again damped by the lower region 2b when it is reflected on a road surface and returned to the light reception section, and the unnecessary reflected light due to the reflection on the road surface can be removed from the incidence light while the obstacle detecting capability by the upper beam region 3a is not reduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle obstacle detection device equipped with a laser radar device.

[0002]

2. Description of the Related Art Conventionally, as disclosed in, for example, Japanese Utility Model Laid-Open No. 3-14479, a laser beam emitted from an own vehicle toward another vehicle or an obstacle in front of the other vehicle or the obstacle. Receives the reflected laser light that is reflected back to
There is known an obstacle detection device for a vehicle, which includes a laser radar device that measures a distance from the vehicle to the other vehicle or an obstacle and issues an alarm when a dangerous state is detected.

In such an obstacle detection device using a laser beam, it is necessary to consider as little as possible the reflected light from an object (unwanted target) other than the target. A road surface is one of the typical unnecessary targets, and due to pitching of the vehicle body or the like, reflected light from a considerably strong road surface is incident on the light receiving unit of the laser radar device at a short distance.

Therefore, conventionally, in order to attenuate the reflected light at a short distance, a method of lowering the sensitivity at a short distance has been adopted.

[0005]

However, when the method of reducing the sensitivity at a short distance is adopted, all the reflected light from a short distance is uniformly attenuated, so that a strong reflection like a rear reflector of a preceding vehicle is generated. Sometimes an object that can obtain light can be detected, but an object that can only obtain weak reflected light cannot be detected.

The present invention has been made in view of the above circumstances, and provides an obstacle detection device for a vehicle capable of attenuating road surface reflected light and the like without reducing sensitivity at short distances. The purpose is to do.

[0007]

In a vehicle obstacle detection device according to the present invention, a laser light transmitting cover member partially provided with a region having a low transmittance for laser light is provided in front of the laser radar device. The region having a low transmittance for the laser light is provided below the cover member in order to attenuate road surface reflection of the laser light, for example.

Further, the region having a low transmittance for the laser light may be constituted by a liquid crystal whose transmittance is controlled to be lowered according to a predetermined condition. In this case, the liquid crystal is controlled to have its transmittance reduced according to the inclination of the vehicle body such as pitching.

Further, a laser light transmitting cover member having a region for attenuating sunlight or the like incident from above formed in the upper portion may be provided in front of the laser radar device.

[0010]

According to the present invention, since the laser light transmissive cover member is partially provided with a region having a low transmittance for laser light, the region having a low transmittance is located below the cover member. In the case of the above, it is possible to attenuate unnecessary reflected light due to road surface reflection or the like without lowering the obstacle detection capability of the laser light, and prevent erroneous detection.

[0011]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is an explanatory diagram showing the basic construction of a first embodiment of an obstacle detection device for a vehicle according to the present invention.
A cover member 2 that is transparent to laser light is provided in front of the laser radar device 1 mounted on the front part of the vehicle, and the laser light 3 emitted from the light emitting part of the laser radar device 1 is provided. Means that the light that has passed through the cover member 2 reaches an obstacle (not shown) in front of the vehicle, and the reflected light reflected by the obstacle passes through the cover member 2 and returns to the light receiving portion of the laser radar device 1. Is configured.

The cover member 2 has an upper region 2a having a high transmittance for the laser light 3 and a lower region 2 having a low transmittance.
b and the laser radar device 1
The laser beam 3 emitted from the light emitting portion of the laser light and spreading in a funnel shape has an upper beam region 3a with high intensity and a lower beam region 3b with low intensity.

Therefore, the lower region 2b of the cover member 2 is
Lower beam region 3 of laser light 3 that has been transmitted through and is attenuated
When b is reflected on the road surface and returned to the light receiving part of the laser radar device 1, the lower region 2b of the cover member 2 is attenuated again, so that the obstacle detection capability of the upper beam region 3a of the laser beam 3 is reduced. It becomes possible to remove unnecessary reflected light due to road surface reflection or the like from the incident light without the need.

Further, by providing the cover member 2 so as to be movable in the vertical direction, the lower beam region 3 having a low intensity can be obtained without requiring the internal adjustment of the laser radar device 1.
The range of b can be adjusted.

The lower region 2b of the cover member 2 may be formed of liquid crystal whose transmittance to laser light is controlled to be lowered by applying a voltage. FIG. 2 shows, in front of the laser radar device 1, a lower region 2b made of liquid crystal.
It is a schematic diagram showing composition of vehicles 10 which attached cover member 2 provided with.

This vehicle 10 has a transmittance control unit 4 for controlling the laser light transmittance of liquid crystal, a vehicle height sensor 5 attached to each of the four corners of the lower surface of the vehicle body, and a liquid crystal laser according to the pitching of the vehicle body. In order to vary the transmittance for light, a signal for processing the input signal from the vehicle height sensor 5 to calculate the vehicle body pitch angle θ and outputting a signal corresponding to the pitch angle θ to the transmittance control unit 4 And a processing unit 6.

The signal processing section 6 calculates the vehicle body pitch angle θ by the following equation.

Θ = tan ^-1 [((H _RL + H _RR )-(H _FL + H
_FR )) / 2 ・ L] However, L: Front-rear distance of sensor H _FL : Front left vehicle height H _FR : Front right vehicle height H _RL : Rear left vehicle height H _RR : Rear right vehicle height Figure 3 shows 6 is a flowchart showing the contents of a transmittance control routine for the liquid crystal. In addition, S represents each step.

In this transmittance control routine, the vehicle height is first detected (S1), and then the vehicle body pitch angle θ is calculated by the above equation (S2). Then, the calculated vehicle body pitch angle θ is compared with a predetermined angle θ ₁ (S3), and when θ> θ ₁ (S3: YES), the laser light transmittance of the liquid crystal is lowered (S4). On the other hand, when θ ≦ θ ₁ (S3: NO),
The normal laser light transmittance is maintained (S5).

Instead of the vehicle height sensor 5, a stroke sensor 9 for detecting the stroke of each of the front and rear suspension members 7, 8 is provided, or a rotary potentiometer for detecting the swing angle of a suspension arm (not shown) is provided. The vehicle body pitch angle θ may be calculated based on the output of the sensor.

FIG. 4 is an explanatory diagram showing the basic construction of the second embodiment of the vehicle obstacle detection device according to the present invention.

In this embodiment, in order to remove the influence of ambient light R such as sunlight incident from above, a liquid crystal region 2c that attenuates the ambient light R is formed above the cover member 2. Then, as shown in FIG. 5, an optical sensor 11 for detecting ambient light is provided on the vehicle body, and the light transmittance of the liquid crystal is lowered based on the ambient light detection by the optical sensor 11. By performing processing such as providing a slit on the front surface of the optical sensor 11, it is possible to detect only the light in the direction that affects the laser light.

The flowchart of FIG. 6 shows the contents of the transmittance control routine in this case. That is, first, the disturbance light amount P is detected (S11), then the detected disturbance light amount P is compared with a predetermined light amount P ₁ (S12), and when P> P ₁ (S12: YES), the liquid crystal light The transmittance is lowered (S13). When P ≦ P ₁ (S12: N
O), the normal laser light transmittance is maintained (S
14).

When the cover member 2 is arranged in front of the laser radar device 1, there is a possibility that the reflected light from the cover member 2 may be received. In that case,
As shown in, the cover member 2 can be excluded from the detection region 12 by providing a predetermined distance between the light emitting unit 1a and the light receiving unit 1b of the laser radar device 1. That is, in the range indicated by reference numeral D in FIG. 7, since the light transmitting range 13 and the light receiving range 14 do not overlap with each other, even if there is an object in the range, the detection cannot be performed.

Alternatively, as shown in FIG. 8, by arranging the cover member 2 so as to be inclined with respect to the optical axis of the laser light 3, the reflected light may escape downward and the detection of the reflected light may be disabled. .

[Brief description of drawings]

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

FIG. 2 is a schematic diagram showing a configuration of a vehicle to which the first embodiment of the present invention is applied.

3 is a flowchart showing the contents of a transmittance control routine in the configuration of FIG.

FIG. 4 is an explanatory diagram showing a basic configuration of a second embodiment of a vehicle obstacle detection device according to the present invention.

FIG. 5 is a schematic diagram showing a configuration of a vehicle to which a second embodiment of the present invention is applied.

6 is a flowchart showing the contents of a transmittance control routine in the configuration of FIG.

FIG. 7 is an explanatory diagram showing an example of means for preventing reflection of laser light from a cover member.

FIG. 8 is an explanatory view showing another example of means for preventing reflection of laser light from the cover member.

[Explanation of symbols]

 1 Laser Radar Device 2 Laser Light Transparent Cover Member 3 Laser Light 4 Transmittance Control Section 5 Vehicle Height Sensor 6 Signal Processing Section 7, 8 Suspension Member 9 Stroke Sensor 10 Vehicle 11 Optical Sensor

Claims (5)

[Claims] 1. A laser for measuring a distance from the own vehicle to the obstacle by receiving a reflected laser light emitted from the own vehicle toward an obstacle ahead of the vehicle and reflected by the obstacle and returning. An obstacle detection device for a vehicle equipped with a radar device, characterized in that a laser light transmissive cover member partially provided with a region having a low transmittance for laser light is provided in front of the laser radar device. Obstacle detection device. 2. The obstacle detection device for a vehicle according to claim 1, wherein a region having a low transmittance for the laser light is provided below the cover member. 3. The obstacle detection device for a vehicle according to claim 1, wherein the region having a low transmittance for the laser beam is made of liquid crystal whose transmittance is controlled to be reduced according to a predetermined condition. 4. The obstacle detection device for a vehicle according to claim 3, wherein the liquid crystal is controlled to have its transmittance lowered according to the inclination of the vehicle body such as pitching. 5. A laser for measuring a distance from the own vehicle to the obstacle by receiving a reflected laser light, which is a laser beam emitted from the own vehicle toward an obstacle in front of the vehicle and reflected back to the obstacle. In a vehicle obstacle detection device equipped with a radar device, a laser light transmissive cover member having a region for attenuating sunlight or the like incident from above formed in the upper part is provided in front of the laser radar device. An obstacle detection device for a vehicle.