WO1995004670A1

WO1995004670A1 - Method and device for automatic control of light equipment on vehicles

Info

Publication number: WO1995004670A1
Application number: PCT/NO1994/000132
Authority: WO
Inventors: Terje Moen; Per SCHJÖLBERG; Anton Gjevik
Original assignee: Sinvent As
Priority date: 1993-08-06
Filing date: 1994-08-04
Publication date: 1995-02-16
Also published as: NO932802D0; AU7469094A; NO932802L

Abstract

It is disclosed a method and device for automatic exchange of messages between vehicles (A, B), such as automatic control of light equipment. At least a first vehicle (A) is provided with equipment comprising at least one unit (1) for reception of infrared light. The unit (1) is connected to an electronic logical unit (5), which unit (5) is connected to equipment controlling the security systems for lights, brakes, etc. of said first vehicle, and/or equipment for presentation to the driver of said first vehicle. At least one retroreflective reflector is installed at the second vehicle (B). The first vehicle (A) is provided with a unit for modulating the infrared signal (2) in different ways for different purposes, and transmits the infrared signal (2), which is detected at the second vehicle (B). The detected, incident light (3) is interpreted in the logical unit (5), and any desired action is performed at the first vehicle (A).

Description

Method and device for automatical control of light equipment on vehicles.

Present invention concerns a method and device for automatic control of light equipment on vehicles, according to the introductory part of Claims 1 and 6, respectively.

Most traffic accidents happen due to human errors. Although the roads and vehic¬ les have become better, the number of vehicles has increased largely, and the claims against the driver often exceed the capacity of each person. Traffic accidents are often caused by a complex situation, and security measures should be viewed from a greater context, and put into a system.

When driving in the dark, the risk of accidents is twice as high as in daylight, and a third of all traffic accidents occur when driving in the dark. Normally, the sight collects approximately 75% of all information, and bad light conditions imply that the driver is less functional and that there exists a greater risk for accidents to occur. Many drivers have a lack of knowledge and skill concerning the use of the light equipment. Generally the driver is most busy in not dazzling his fellow travelers. Usually this has the consequence that the driver changes from main beam to dipped beam far too early, and back to the main beam far too late. The result will be that in the most critical situations, most drivers use dipped beam. It is also a problem that driving in the dark generally is a great stress factor for the driver. In order to use the light equipment correctly, it is necessary to be con¬ centrated all the time, and, consequently, the ability to spot dangerous situations will be further reduced. Previously it is tried to provide equipment for automatically alteration between dipped beam and main beam. The simplest systems comprise a light detector that detects the main beam of the oncoming vehicle, and dipping on basis of light inten¬ sity and/or the waveform of the beam of light. This does not include a set of criteria that are sufficient for correct dipping. If the oncoming vehicle has extra main beam, it will be dipped far too early. In more developed system for automatic dipping is used the infrared part of the light spectrum from the oncoming vehicle. In such a solution it is avoided that extra main beam give fault information to the automatic device. It is necessary with a kind of filtering of the IR-part of own main beam, to avoid distracting reflections. Such systems are previously known, i.e., from SE-362.388, EP-230.620, EP-479.634 and US-3.188.519. Common to all these systems is that only light from oncoming traffic is being detected. Dipping for vehicles driving in front must be performed manually. From US-3.751.711 is previously known a device that is based on the use of IR- lights and IR-detectors. As source for the IR-lights is used a modified version of the vehicle's own main beam, equipped with certain filters. The IR-detector responds to the beam from the oncoming vehicle, and the rear lights of the vehicle driving in front. The emission of IR-light from the main beam is being reduced to a little above the emission from the rear lights, for example in the relationship 100:15. It is neces¬ sary that all vehicles are equipped with filters at the main beam, which represent a considerable disadvantage in this system. Furthermore, it is not considered vehicles that do not have halogen lamps in the rear lights; this will have a reduced light inten¬ sity over a certain time. Dirty rear lights will also disturb the operation. There are considerable disadvantages in using the beam of the oncoming vehicles to calculate when own vehicle should dip. This fact is, among other things, due to the great variation in the emission of light from the main beam of the vehicles. The reflectors loose gradually their reflecting abilities, the glasses are getting worn, and in addition there are variations from one type of vehicle to another. Other factors are the condition of the light bulb, and the size of the input voltage.

In due time, low energy sources will replace the halogen based light sources of today. Low energy sources have less use of energy and longer life than light bulbs of today. This is achieved by the infrared part of the light being substantially reduced. Thus the use of main beam as IR-source is made further difficult. An IR-based light control system should therefore be self-contained with IR-light.

It is therefore an object of present invention to provide the method and device for automatic control of light equipment on vehicles that dip when the beam, objectively viewed, is starting to dazzle the driver of the other vehicle. The object of the invention is achieved with a method and device having features as stated in the characterizing part of Claim 1 and 6, respectively. Further features are clear from the independent claims. In the following the invention will be describing more in details, using an example of embodiment and reference to the enclosed drawings, where

Fig. 1 shows a sketch of an automatic lights control system according to present invention, with two oncoming cars, of which one is fully equipped with automatic control, and the other is equipped with reflectors,

Fig. 2 shows a first curve of a signal emitted by a system according to present invention,

Fig. 3 shows another curve of a signal emitted by a system according to present invention, Fig. 4 shows a third curve of signal emitted by system according to present invention, and

Fig. 5-10 shows use of lights equipment in vehicles in different traffic situations where present invention is being used.

By referring to Fig. 1 is disclosed two oncoming vehicles A and B, where vehicle A is fully equipped with automatic lights control, and vehicle B is equipped with ref¬ lectors. In vehicle A is schematically shown the different components of the equip¬ ment. A transceiver 1 is mounted to the windscreen of the vehicle A, in principle in the height of the driver's head. A corresponding transceiver (not shown) is also mounted to the back window of the vehicle, preferably included in high brake lights. The transmitter part of the transceiver 1 emits light signals in the infrared area, shown in Fig. 1 with a light cone 2. The emitted infrared light will spread both in horizontal and vertical plane. The spread in the vertical plane is calculated from desired area of coverage in a per se known manner, where it is also considered that the angle should be limited in order to achieve sufficient luminance.

The horizontal angle is calculated from a model for correct use of the main beam. When two vehicles are approaching, the change from dipped beam to main beam should be performed in a distance corresponding to the length of two cars, which is approximately 11 m. By defining to lateral distance between two cars to 2 m and the distance from the outer side of each car to the center of the IR-transceiver to 1 m, the angle will become:

The calculation is valid for the angle with one of the sides. In order to cover both sides the angle should be doubled, which gives approximately 40° . The distance for change from dipped beam to main beam is also set to approximately 11 m when passing of vehicles. The receiver part of the transceiver 1 comprises two detectors, one for infrared light and one for visible light. Vehicle B is shown in Fig. 1 with a retroreflective reflector 4, which provides a reflected signal back to the transceiver 1 at vehicle A. Rear and forward reflector should be adapted to the relationship between desired dipping by vehicles approaching from forward, or vehicles approaching from behind. This relationship should be approximately 2: 1. Experiments have shown that correct distance for dipping is in the area of 250-400 m. This distance should be tried in practice. A dipping distance of approximately 400 m when vehicles meet, and app¬ roximately 200 m when vehicles are caught up with, can be an applicable basis. It should be taken into consideration that different types of cars have different inclin- ation of the windscreen and the back window. The reflectors should be adapted thereto. Particularly the back windows are different, from almost vertical windows (estate cars and vans) to more horizontal windows in some saloon cars. This inclin¬ ation affects the reflective ability by the effective area becoming different. Installation of reflector on the back window only applies to private car without trailer. For other vehicles, as vehicles with trailer, bus, truck and special vehicles as road maintenance machines, the reflector can, e.g. , be arranged on an external mir¬ ror. The point is that the reflector is mounted in the eye height of the driver.

The transceiver 1 is connected to an electronic logical unit 5, which by means of a relay 6 controls the switching between dipped beam and main beam. In operation, a modulated infrared light signal 2 emitted from the transmitter part of the transceiver 1. This light signal will be reflected from other vehicles, which are equipped with reflectors, either oncoming vehicles having reflectors on the wind¬ screen, or vehicles caught up with, having reflectors on the back window. The ref¬ lected light signal 3 is detected by the receiver part of the transceiver 1. At a certain intensity of the reflected signal, the electronic unit 5 cause the vehicle to dim its main beam. The level of this intensity is adjustable, and is determined by the strength of own main beam. If received IR-signal does not originate from own emitted beam, the signal is ana- lyzed in order to determine if it is a signal from a different vehicle equipped with a similar system. The oncoming vehicle B may transmit a message that it is dazzled, and the vehicle A should in that case dim its main beam.

The system may modulate emitted light signal in different ways, dependent upon the optimal conditions. Modulations of current interest are PPM (Pulse Position Modulation), PWM (Pulse Width Modulation), PDM (Pulse Duration Modulation) or FM (Frequency Modulation). Within the chosen modulation method, different messages may be given. In Fig. 2-4 are shown examples of different frequency modulations of the emitted signal. This is only an example; modulation and type of signals emitted for different messages may be varied from what is most suitable for the purpose.

In Fig. 2 is shown the normal condition to emitted IR-signal, a saw-tooth modu¬ lation having increasing frequency. If the system registrate dazzling from an oncom¬ ing vehicle, the signal is changed to what is shown in Fig. 4, a saw-tooth modulation having decreasing frequency. This signal implies instruction to the oncoming vehicle to dim. If oncoming vehicle only have reflectors mounted, the system will registrate reflection a reflection of its own emitted signal. This means that the oncoming vehicle is in danger of being dazzled, and the system will change from main beam to dipped beam. Irrespective of the waveform of the reflected signal, the system will dim at received reflection. In order to the signal being interpreted as reflector, the received signal should have the same waveform and phase.

In Fig. 4 is shown the waveform that is emitted when the vehicle drives with dip¬ ped beam. When the vehicle initially emits the waveform shown in Fig. 2 or Fig. 3, and then dims, the waveform will change to what is shown in Fig. 4. If the system detects IR-light of known waveform, which is not reflected by own beam, the signal will be interpreted, and action will be taken according to the following: Message (Fig. no.) Action

2 Change to main beam

3 Change to dipped beam

4 Change to main beam

If reflector of own signal is received simultaneously, this will determine which action will be taken.

The transceiver 1 is also equipped with a detector, detecting visible light. If this detector registrate ambient light above a certain intensity, the system will automat- ically change to dipped beam. This action will be performed along distances having sufficiently strong road illumination, or in daylight.

In fig. 5-10 is demonstrated the function of a light control equipment according to present invention. In the figures, vehicle B is equipped with a means for automatic light control, while other vehicles are equipped with reflector. In all the examples, the situation is driving in a two-lane road with oncoming traffic.

In fig. 5 is vehicle A approaching vehicle B. In a certain distance, B will detect the IR-reflector of vehicle A, and thus change to dipped beam. When vehicle A is outside the infrared horizontal detection area of vehicle B, vehicle B will auto¬ matically switch to the main beam. In fig. 6 and 7, vehicle B reaches vehicle A. In a certain distance, vehicle B will detect the IR-reflector of vehicle A, and change to dipped beam (fig. 6). When A is outside the IR detection area of vehicle B, B will automatically switch to main beam.

Fig. 8 illustrates that by an encounter of more vehicles, vehicle B will not switch to main beam before last vehicle has past out of the detection area of B. The system will also detect vehicles that meet in a turn. This situation is shown in fig. 9. If vehicle A has automatic lights control, it will drive with the main beam as long as vehicle D is outside the detection area.

In fig. 10 is illustrated a situation where the driver of vehicle B could be dazzled by vehicle A, as the main beam of vehicle B are hidden by a hilltop and the driver in vehicle A is then inhibited to registrate vehicle B. The IR-reflector of B is mounted in the eye-height of the driver, and will reflect the IR-light back to A, which will dim in a correct distance before the driver in vehicle Ν is dazzled. The reflector can be made compulsory for all vehicles by being given away for free by the road authorities, for example as a receipt for paid road toll or as a doc¬ umentation that the vehicle should not pay such toll. The reflector should then be equipped with descriptive print (text + logo), and the registration number of the vehicle. The print side is the glue side of the reflector. The print should be provided in such a way that it does not hinder IR-reflection. The reflector should be made optimal for IR-light, but it should also be appreciated to make it reflective for visible light. In this way all vehicles will have a reflector also in front. Vehicles will then be easier visible, for example when parking in the edge of the road, which will increase traffic security.

The disclosed system presupposes that every vehicle either has this system instal¬ led, or at least is equipped with a retroreflective reflector in the eye height of the driver, preferably on the windscreen and back window. A system having communication between vehicles by modulated infrared signals can also be used to a number of different objectives then what is concerned use of lights. An example can be signals for ensuring a certain distance between vehicles. Especially in a queue it can be useful, as a signal containing a message about break¬ ing can be transmitted backwards in a queue from vehicle to vehicle. Furthermore, emergency vehicles can transmit special signals, alerting emergency. In tunnels it can be arranged certain IR-lighthouses, which for example can transmit catastrophe alarm to all vehicles simultanuosly. In such a system it should be instal¬ led display in the vehicles, so that the driver is noticing the content of the message. This can for example be a headup display (HUD) showing a symbol, as a break sym¬ bol. It can also be necessary that such a total system automatically takes control over parts of the vehicle, for example in order to maintain minimum distance to the vehic¬ les driving in front.

In order to make the system work, it is also most important that the reflector is clean. When mounted on the inside of the windscreen the cleaning will be caused, among other things, by the wiper of the vehicle. By coating or wear on the wind- screen, less IR-light will be reflected, and danger of dazzling will be increased cor¬ respondingly. This will motivate to keep the windscreen clean and perfect, which is an important traffic security measure independent of present invention. The demand for cleanness also applies to the reflector mounted on the back window. Cars that are exposed to dirt on the back window often have a rear wiper, and the reflector should be situated within the area of this rear wiper. When mounted on the side mirror, for example on trucks, the cleaning can be done in a simple manner from the driver's cab. If the reflector is distributed in connection with paid road toll, the reflector will be renewed annually. This will inhibit problems that can be caused by age of the reflector material due to sunlight, etc.

Claims

Claims:

1. Method for automatic exchange of messages between vehicles (A, B), such as automatic control of light equipment, where at least a first vehicle (A) is provided with equipment comprising at least one unit (1) for reception of infrared light, which unit (1) is connected to an electronic logical unit (5), which unit (5) is connected to equipment controlling the security systems for lights, brakes, etc. of said first vehic¬ le, and/or equipment for presentation for the driver of said first vehicle; the method comprising the following steps: transmitting an infrared light signal (2) from a light source at said first vehicle (A), detecting incident infrared light (3) in said logical unit (5), and effecting possible action at said first vehicle (A), characterized by at least one retroreflective reflector being installed at said second vehicle (B), modulating said infrared signal (2) from said first vehicle (A) in different ways for different purposes, transmitting said modulated, infrared signal from said first vehicle (A) by an own transmitter associated with said unit (1), receiving a light signal reflected from said second vehicle (B), and causing an action on the basis of information in the received signal.

2. Method according to claim 1, characterized by a retroreflective reflector (4) being installed in the front of, and a retroreflective reflector (4) is installed in the back of the vehicles (A, B); both reflec¬ tors are situated in the eye height of the driver.

3. Method according to claim 2, characterized by the front reflector (4) is reflecting more light than the front reflector (4).

4. Method according to claim 1-3, characterized by at automatic lights control, the modulated infrared signal contains different codes in order to give message indicating normal driving with main beam, give message to oncoming vehicles to change from main beam to dipped beam, and for normal driving with dipped beam.

5. Method according to claim 1-4, characterized by detecting visible light, and changing between main beam and dipped beam is performed based on the intensity of ambient light.

6. Device for automatic exchange of messages between vehicles (A, B), such as automatic control of light equipment, where at least a first vehicle (A) is provided with equipment comprising at least one unit (1) for reception of infrared light, which unit (1) is connected to an electronic logical unit (5), which unit (5) is connected to equipment controlling the security systems for lights, brakes, etc. of said first vehicle, and/or equipment for presentation to the driver of said first vehicle, characterized by at least one retroreflective reflector being installed at said second vehicle (B), and the at least first vehicle (A) is provided with a unit for modulating said infrared signal (2) in different ways for different purposes, and an own transmit¬ ter, associated with said unit (1), which transmitter transmits the infrared signal (2).

7. Device according to claim 6, characterized by transmitter and receiver for infrared light constitute a transceiver

(1).

8. Device according to claim 6-7, characterized by the receiver part of the transceiver (1) comprising a detector for infrared light.

9. Device according to claim 6-9, characterized by the receiver part of the tranceiver (1) comprising a detector for visible light.