JP2000067399A - Laser radar device adaptive to environment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laser radar device capable of preventing a malfunction by weather conditions. SOLUTION: This device is provided with a position detection means (car navigation system) for detecting the geographical position of a vehicle, a weather information detection means (field-of-vision sensor 5) for detecting weather information, a communication means (antenna 7) for communicating the weather information to the vehicle, a first judgement means (microcomputer 10) for judging whether or not to operate a system from the weather information, a second judgement means (microcomputer 10) for judging whether or not a traveling road is suited to the condition of operating the system, an inhibition means (microcomputer 10) for inhibiting all or a part of the control of the system in the case that the first judgement means or the second judgement means (microcomputer 10) judges not to operate the system and a notification means (microcomputer 10) for notifying a driver of the operation of the inhibition means at the time of operating it.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a scanning type laser radar device for detecting a detection object ahead in a traveling direction while a vehicle is traveling, and more particularly to a scanning laser radar device used as an inter-vehicle distance sensor.

[0002]

2. Description of the Related Art In recent years, a laser radar device has been put into practical use as an inter-vehicle distance sensor while a vehicle is running, and is used for applications such as automatically maintaining a constant inter-vehicle distance or monitoring the inter-vehicle distance during running. Have been.

The basic principle is as follows. That is, a laser beam (pulse wave or amplitude modulated wave)
Is irradiated toward the detection target while scanning within a predetermined angle, and reflected light from the detection target is received. At that time, since the propagation speed of light in the atmosphere is almost constant, it is necessary to know this time by using the principle that the time required for light to be reflected by the detection target and return is proportional to the distance. Is used to measure the distance to the detection target.

[0004] On the other hand, it is known that laser light is scattered by airborne substances, particularly snow and fog, and is remarkably attenuated due to its physical properties. Therefore, a target object as an inter-vehicle distance sensor is known. There was a significant drawback that the detection accuracy was dependent on weather conditions. For example, when an inter-vehicle distance control system is configured based on inter-vehicle distance data of a laser radar device, it is recognized as an obstacle by a reflected signal from snow, fog, or the like. ) May be activated.

In order to avoid such a malfunction, the system is not operated based on a signal such as a wiper signal or an automatic transmission mode (snow road correspondence mode) signal which reflects a driver's intention to weather conditions. Or do
Alternatively, a system has been put into practical use that performs control to increase the laser output and increase the detectable distance. However, these signals do not always reflect actual weather conditions, and in some situations the system may malfunction under dangerous conditions. For example, the wiper operation may not be required when driving during snowfall, but in such situations the system will operate normally and control will be based on an erroneous distance signal due to reflections due to the presence of snow. This may cause a malfunction such as sudden deceleration or acceleration.

In Japanese Patent Application Laid-Open No. 7-318650, an environment sensor for detecting rainfall, light transmittance, and the like is provided in a laser radar device.
There has been proposed a laser radar device in which a function for estimating a weather condition and adjusting a laser light intensity is added.

[0007]

However, providing each vehicle with an environmental sensor as described above requires the following.
It is not practical because it leads to cost increase.

[0008] Among the contents disclosed in the above-mentioned publications, there has been proposed one that uses the operation of a wiper or a fog lamp as a visibility defect detecting means.
As described above, there is a possibility that a malfunction may occur, and this is not an effective means.

Further, the above publication only controls the laser light intensity according to the weather conditions, and does not mention any processing when the detectable distance is insufficient even when the laser light intensity is maximized. Absent.

Therefore, the present invention has been made in view of the above circumstances, and has as its technical object to provide an inexpensive environment-friendly laser radar device which can prevent malfunction due to weather conditions and is inexpensive. is there.

[0011]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned technical problem. The invention is directed to a distance and an azimuth of a predetermined area ahead of a vehicle in a traveling direction with respect to a detection object located in the area. In a laser radar device that detects
Position detecting means for detecting a road and a geographical position on which the vehicle is traveling; weather information detecting means for detecting weather information of the geographical position detected by the position detecting means; Communication means for communicating the meteorological information to the vehicle, and from the geographical position detected by the position detecting means and the weather information of the geographical position received by the communicating means, indicate whether the system can be operated. First judging means for judging whether or not the traveling road detected by the position detecting means conforms to a condition enabling the system to operate, and the first judging means Alternatively, when the second determination unit determines that the system is not to be operated, a prohibition unit that prohibits all or a part of the control of the system; If all or part of the control stem is prohibited, and a laser radar apparatus characterized by comprising a notification means for notifying the driver wheel.

In the above invention, the position detecting means for detecting the road on which the vehicle is traveling and the geographical position correspond to a car navigation system which has been put into practical use in recent years. Description is omitted.

The weather information detecting means is not mounted on each vehicle, but is installed at a predetermined position on each road as a part of traffic control means such as ITS (intelligent road communication system) related infrastructure equipment. For example, a visual field sensor or the like is assumed. With this weather information detecting means, weather information around the position where the vehicle is currently traveling is detected.

The communication means serves to communicate the weather information detected by the weather information detection means to the vehicle. For example, the communication means transmits the weather information detected by the weather information detection means installed at various positions to the vehicle. It is assumed that there is an external relay station that performs centralized management before transmission to the satellite, and an antenna mounted on a vehicle that receives weather information transmitted from the relay station.

The first judging means uses a system (for example, an inter-vehicle distance control system) in conjunction with the laser radar device based on the geographical position detected by the position detecting means and the weather information of the geographical position received by the communication means. ) Is determined. For example, in a situation where the visibility around the current traveling position is extremely poor due to severe snowfall or the like, the received weather information recognizes that the visibility is extremely poor, and completely prohibits the control of the following distance control system. Make a judgment. In a situation where the visibility is somewhat poor due to light snowfall or the like, it is determined that a part of the control of the inter-vehicle distance control system is prohibited.

The second judging means judges whether or not the traveling road detected by the position detecting means conforms to the conditions for operating the system. For example, when the weather information detecting means (infrastructure equipment) is not yet installed on the road on which the vehicle is currently traveling, weather information cannot be received, and even if the weather deteriorates, the laser Since the radar device cannot recognize it, it may cause a malfunction, and determines that the control of the following distance control system is completely prohibited.

The prohibiting means may be the first determining means or the second determining means.
When the determination means determines that the system is not to be operated as described above, the determination means plays a role of inhibiting all or a part of the control of the system linked to the laser radar device.

The notifying means, when all or a part of the control of the system linked with the laser radar device is prohibited by the prohibiting means, notifies the driver to the effect by an alarm, a warning light or the like. It plays a role.
At this time, it is possible to distinguish between a case in which all the controls are prohibited and a case in which some of the controls are prohibited. It is desirable to adopt a notification method that allows the user to know whether the notification is effective.

The laser radar apparatus according to the present invention employs the above-described configuration, whereby the accuracy of detecting a target can be improved in the case of bad weather such as snow or fog or when infrastructure facilities are not maintained. May be dependent on
Control of a system (inter-vehicle distance control system) linked to the present apparatus can be reliably prohibited, and occurrence of malfunction can be reliably suppressed. Also, since the weather information detection means is not mounted on each vehicle individually,
Cost reduction is possible as compared with the prior art. Furthermore, if all or part of the control of the system is prohibited, the driver can know so, so that it is known in advance that more careful driving is required, It can contribute to prevention.

[0020]

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

FIG. 1 is a diagram showing an operation state of an environment-friendly laser radar device for an inter-vehicle distance sensor according to an embodiment of the present invention. In FIG. 1, reference numeral 1 denotes a vehicle, and an environment-friendly laser radar device 2 is provided at a front portion of the vehicle 1.

The environment-friendly laser radar device 2 can set the detection range of the emitted laser beam based on a signal from a vehicle speed sensor (not shown). The operation will be described later with reference to FIG.

In FIG. 1, the laser beam 4 emitted from the environment-friendly laser radar device 2 toward the preceding vehicle 3 is reflected before reaching the preceding vehicle 3 due to the presence of the fog 8, and the environment is reduced. Compatible laser radar device 2
You are trying to recognize the wrong distance signal. A visibility sensor (infrastructure equipment) 5 (meteorological information detecting means) is installed on the road in an area where fog 8 is generated in front of the vehicle 1,
The visibility sensor 5 transmits the visibility information reduced by the fog 8 to the relay station 6 (communication means) as weather information. The relay station 6 that has received the weather information transmits the weather information to the vehicle 1. The vehicle 1 receives the weather information via the receiving antenna 7 (communication means), and the received weather information is supplied to the environment-friendly laser radar device 2. Similarly, view information obtained from a view sensor 5 (not shown) installed at other positions is also supplied.

The environment-friendly laser radar device 2 is supplied with information on a road on which the vehicle is currently running and a geographical position from a car navigation system (position detecting means) (not shown) mounted on the vehicle 1. Based on the supplied information on the geographical position, the environment-friendly laser radar device 2 selects the weather information of the visibility sensor 5 installed around the position where the vehicle is currently traveling, and selects the visibility reduced by the fog 8. Recognize information.

The microcomputer 10 (see FIG. 2) (first judging means) in the environment-friendly laser radar device 2 which recognizes the lowered visibility information completely controls the inter-vehicle distance control system (not shown) in conjunction therewith. Make a decision to prohibit.
Further, the microcomputer 10 (second determining means) determines whether or not the running road is suitable for the conditions that can operate the inter-vehicle distance control system, based on the supplied information on the currently running road. The road in the situation shown in FIG.
A value of 0 does not determine that control of the following distance control system is prohibited. As described above, the microcomputer 1 as the first determination means
0 has determined that the control of the following distance control system is completely prohibited, so the microcomputer 10 (prohibiting means)
A signal indicating that control of the inter-vehicle distance control system is completely prohibited is supplied to the inter-vehicle distance control system.

The microcomputer 10 (notification means) activates an alarm or a warning light to notify the driver that the control of the following distance control system is completely prohibited.
Call attention.

With the above operation, the environment-friendly laser radar device 2 completely inhibits the control of the inter-vehicle distance control system in the situation of FIG. 1 and thus malfunctions due to recognition of an incorrect distance signal. Can be reliably prevented. Further, the driver is notified by an alarm or the like that the control of the inter-vehicle distance control system is completely prohibited, so that he can drive more carefully and contribute to the prevention of accidents due to safe driving.

FIG. 2 is a block diagram showing the operation principle of the environment-friendly laser radar device for an inter-vehicle distance sensor according to one embodiment of the present invention. The environment-friendly laser radar device 2 is provided with a microcomputer 10.
When the microcomputer 10 issues a trigger signal to the driver 11, the driver 11
, A momentary pulse current is injected. The pulse laser diode 11 into which the pulse current has been injected emits a laser beam (transmission pulse 14) proportional to the injected current.
Irradiate toward 6. At the same time, the microcomputer 1
0 transmits the counter start signal to the interval timer / counter 19 and the interval timer / counter 1
9 starts the counter operation. This is the starting point of the measurement time width. Here, the peak power of the transmission pulse 14 is set to a value sufficient to satisfy the required detection distance performance of the inter-vehicle distance detection system, and the light emission period is required for averaging processing to satisfy the required distance measurement resolution. It is determined by the number of samples and the responsiveness required by the system.

When irradiating the transmission pulse 14, the microcomputer 10 transmits a scan range control command to the scanner 13 (scan angle control means) based on the own vehicle speed data from the vehicle speed sensor 9 to correspond to the vehicle speed. The transmission pulse 14 is deflected and scanned within a scan range (scan angle). The scanning method is generally based on a polygon mirror, but a galvano mirror may be used. Further, the microcomputer 10 transmits a beam width control signal to the collimating lens 12 (spreading angle control means) based on the own vehicle speed data from the vehicle speed sensor 9, and controls the distance between the pulse laser diode 11 and the collimating lens 12. Thus, the beam width (spread angle) is adjusted according to the vehicle speed.

Received pulse 1 reflected by target 16
5 is a PIN photodiode 1 via a light receiving lens 17.
The light is condensed at 8, extracted as a photocurrent, amplified through an amplifier 18, and then supplied to an interval timer / counter 19 as a counter stop signal. The interval timer / counter 19 supplied with the counter stop signal stops the counting operation started by the counter start signal. Since this counted value is proportional to the measurement time width, that is, the distance to the target 16,
The microcomputer 10 can obtain distance data to the target 16 by multiplying this value by an appropriate coefficient.

By repeating the above operation, the distance data to the target 16 at each scanning point is calculated inside the microcomputer 10, and together with the scanning angle by the scanner 13,
The information is supplied to the target recognition logic in the inter-vehicle distance control system, and the distance and the azimuth to the target 16 can be recognized. This information is supplied to the inter-vehicle distance control system so that, for example, automatic control of the inter-vehicle distance can be performed.

Although the present invention has been described with reference to the above embodiment, the present invention is not limited to the above embodiment.
It includes various aspects according to the principles of the present invention.

[0033]

According to the present invention, an erroneous operation due to weather conditions can be prevented, and an inexpensive environment-friendly laser radar device can be provided.

[Brief description of the drawings]

FIG. 1 is a diagram showing an operation state of an environment-friendly laser radar device for an inter-vehicle distance sensor according to an embodiment of the present invention.

FIG. 2 is a block diagram illustrating an operation principle of an environment-friendly laser radar device for an inter-vehicle distance sensor according to an embodiment of the present invention.

[Explanation of symbols]

Reference Signs List 1 vehicle 2 environment-friendly laser radar device (laser radar device) 5 visibility sensor (weather information detecting means) 6 relay station (communication means) 7 antenna (communication means) 10 microcomputer (first judgment means, second judgment means, prohibited) Means, notification means)

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 5H180 AA01 BB04 CC03 CC12 CC14 EE12 FF13 FF21 LL01 LL04 LL07 LL08 5J084 AA02 AA04 AA05 AA07 AA10 AB01 AB08 AC02 AD01 AD06 AD20 BA04 BA11 BA18 BA36 BA49 BB02 CA07 EA20 EA22 EA23 EA28 EA29

Claims (1)

[Claims] 1. A laser radar device for detecting a distance and an azimuth angle of a predetermined area ahead of a traveling direction of a vehicle with respect to a detection target located in the area, the road and the geographical position on which the vehicle is traveling. Position detecting means for detecting,
Weather information detecting means for detecting weather information of a geographical position detected by the position detecting means, communication means for communicating weather information detected by the weather information detecting means to the vehicle, and detection by the position detecting means First judging means for judging whether or not the system can be operated based on the obtained geographical position and the weather information of the geographical position received by the communication means, and a running state detected by the position detecting means. Second determining means for determining whether or not the road of the vehicle conforms to conditions that can operate the system;
Prohibiting means for prohibiting all or a part of the control of the system when the judging means or the second judging means judges not to operate the system; and all or a part of the control of the system by the prohibiting means. A laser radar device comprising: a notifying unit that notifies a driving vehicle when prohibited.