JP2001219782A - Optical axis angle adjusting device for headlight - Google Patents

Abstract

PROBLEM TO BE SOLVED: To automatically adjust and control an optical axis angle of a headlight in relation to a car body, to always keep constant an optical axis angle of the headlight in relation to a road surface, and to allow a driver to always, adequately, visually recognize a state of a remote road surface, even if an angle of the car body changes in relation to the road surface depending on an amount of load and its loading position, and number of passengers and their sitting positions. SOLUTION: A distance L from a transmitting/receiving element mounted to the headlight to obliquely front road surface is measured by radar. An angle of the headlight in relation to a car body is controlled by an electrical actuator so as to keep the distance L constant.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is used for a headlight of a vehicle. The present invention automatically adjusts the angle of the optical axis of the headlight with respect to the vehicle body even if the angle of the vehicle body with respect to the ground surface changes, so that the optical axis of the headlight always remains constant with respect to the ground surface. Related to a device that controls so as to be controlled.

[0002]

2. Description of the Related Art A headlight mounted on an automobile is configured such that the angle of an optical axis with respect to a vehicle body can be adjusted within a certain range. The angle of the optical axis is legally regulated so that the beam enters an appropriate range when the beam is operated upward by the driving operation and when the beam is operated downward. In order to comply with this regulation, the angle of the optical axis is individually adjusted and set by using a measuring instrument and a tool at the time of manufacture and vehicle inspection. This is adjusted in principle with no load or passengers other than the driver. This is kept fixed until the next inspection.

[0003] On the other hand, the inclination of the vehicle body with respect to the road surface changes depending on the load and the condition of the passenger. That is, since the inclination of the vehicle body in the front-rear direction with respect to the road surface changes depending on the number of cargoes and the number of passengers, or the loading position and seating position, the angle of the optical axis of the headlight with respect to the vehicle body is appropriately adjusted and set. However, with respect to an object on the ground or a road surface, the optical axis of the headlight is shifted vertically by an amount corresponding to the inclination, and the beam range irradiated by the headlight substantially changes.

Although this change has long been neglected as being very small, a technique for adjusting the change by operation is known. In this method, a headlight is attached to a vehicle body so that the angle of the optical axis thereof can be adjusted, and by operating from a driver's seat, this electric actuator is driven to set the angle of the optical axis of the headlight. It is possible to change within the range. This is popular with heavy-duty vehicle drivers because the beam range of the headlight can be adjusted so that the distant area can be seen best when driving on a country road at night.

[0005]

This device requires manual operation for adjustment according to the condition of the cargo, the seating position of the passenger, and the like. This operation is troublesome to carry out every time a load is loaded and unloaded, and performing the adjustment while the vehicle is running also causes the driver to use extra nerves in addition to the driving operation.

The present invention has been made in such a background, and the angle of the vehicle body with respect to the road surface changes due to a change in the amount of cargo and its loading position, the amount of passengers and its seating position, and the like. It is another object of the present invention to provide a device which can automatically adjust and control the angle of the optical axis of a headlight with respect to a vehicle body and constantly maintain the angle of the optical axis of the headlight with respect to a road surface. The present invention automatically corrects even if the condition of the cargo or the condition of the passenger changes,
It is an object of the present invention to provide a headlight capable of always accurately recognizing a state of a distant road surface.

[0007]

According to the present invention, there is provided a radar means using electromagnetic waves (including light waves) or sound waves (including ultrasonic waves), and a transmitting / receiving element of the radar means is linked with a vertical inclination of a headlight. The radar means observes the distance L to the ground surface obliquely forward or obliquely rearward from the vehicle, and the vertical direction of the headlight so that this distance L is always kept constant. Is automatically controlled. The present invention has a great feature in that the reference of the control is set to a distance L to a road surface diagonally forward (which can also be implemented diagonally rearward).

That is, according to the present invention, the headlight (1) is mounted so that the angle of its optical axis with respect to the vehicle body can be adjusted,
Electric actuator for changing the angle of the optical axis (2)
And a driving circuit (3) for driving the actuator, a headlight optical axis angle adjusting device, wherein a radar means (4) is provided, and the radar means (4) is provided with the headlight (1). A transmission / reception element (5) mounted so that its irradiation angle changes in conjunction with the optical axis of the vehicle, irradiates the road surface obliquely in the traveling direction (front or rear) of the vehicle, and receives reflected waves from the road surface; And an arithmetic circuit (6) for calculating and measuring a distance L from the transmitting / receiving element (5) to the road surface. The drive circuit (3) acquires information on the distance L measured by the radar means (4). A control circuit (7) for automatically controlling the angle of the optical axis so that the distance L is constant is provided.

The numerals in the parentheses are reference numerals for the drawings of the embodiments described later. This is provided so that the configuration is easy to understand, and is not intended to limit the configuration of the present invention to this embodiment (the same applies hereinafter).

Now, assuming that the body frame is a plane (see FIG. 1, the upper diagram of FIG. 1 is a plan view, the lower diagram is a front view),
On this plane, the x axis is set in the traveling direction of the vehicle, and the y axis is set in the lateral direction.
When an axis is taken and a road surface is obliquely looked down from a point P on this plane parallel to the x-axis, the distance L from that point to the ground surface changes according to the angle α of the x-axis to the ground surface. The angle α changes depending on the load status of the vehicle. Accordingly, the angle formed by the optical axis A of the headlight with respect to the road surface also changes.
Now lift the xy plane slightly from the body frame position,
When the point P is located at the position of the headlight, the angle in the vertical plane of the headlight is controlled so that the distance L from the point P to the road surface is constant even if the angle α changes due to the load condition. Then, the angle of the headlight optical axis with respect to the road surface is kept constant.

It is assumed that a heavy load is loaded in front of the vehicle so that the rear portion of the vehicle rises by an angle α from a plane xy when there is no load. Thereby, the distance L from the point P to the road surface when looking down the road surface diagonally is
(See FIG. 2) by the difference ΔL. At this time, if the angle of the optical axis of the headlight (1) is changed in a vertical plane and the difference ΔL is controlled to be zero, the angle of the optical axis A of the headlight with respect to the road surface is determined when there is no load. Becomes equal to

[0012] With this configuration, even if the angle of the vehicle body with respect to the road surface changes due to the size of the load of the vehicle, the size of the passenger, the load position of the load, the seating position of the passenger, and other effects, the headlight can be used. The angle of the optical axis with respect to the road surface is always controlled automatically and constantly. As a result, it is possible to appropriately illuminate a distant road surface and accurately recognize a distant state in the traveling direction. Thereby, the driver does not need to adjust the angle of the optical axis, and can concentrate on the driving operation.

In the above description, the road surface is obliquely looked down from one point P on the plane parallel to the x-axis. However, even if the road surface is not always parallel to the x-axis, the road surface is inclined at a certain angle with respect to the x-axis. Even if it is configured to look down, the effective component (the component parallel to the x-axis) of the measured distance L is reduced, but the present invention can be implemented similarly.

The transmitting / receiving element (5) is provided with the headlight (1).
It is desirable to adopt a configuration that can be attached to the lamp body. On the contrary, the present invention is implemented by attaching the transmitting / receiving element (5) to an object having a structure (a mechanically linked structure or a structure linked via an electric system) interlocked with a headlight other than a lamp body. Can also. In this case, the transmitting / receiving element (5) of the radar means may be configured to look down on the road surface diagonally behind.

When one vehicle is provided with a plurality of headlights, the above-mentioned automatic control system is provided for a specific one headlight, and the other headlights are linked to the specific one headlight. And the optical axis angle can be controlled. With this configuration, a device for controlling the angle of the optical axis becomes inexpensive.

The radar means (4) preferably uses infrared laser light. This is because the spread angle of the infrared laser beam is extremely small, and its wavelength can be easily distinguished from the light energy generated by the headlight. The radar means can be practically realized without difficulty by using a component for automatically setting the focal length of the small camera or a component equivalent thereto.

[0017] The radar means (4) may be configured to use a light beam that is branched from a light beam emitted from the headlight and passes through a filter and a shutter. That is, the light energy generated by the headlight (1) is partially branched, passed through a filter that selectively transmits a limited wavelength, and further passed through an electrostatic shutter that opens and closes at high speed by voltage control. The transmitted light beam is transmitted from the transmitting / receiving element to illuminate the road surface, and the reflected wave from the road surface is also passed through the filter or a filter that selectively transmits the same wavelength as the filter, and the timing of the transmitted light is adjusted by the electrostatic By comparing with the opening / closing timing of the shutter, a propagation time required for the light to reciprocate is obtained, and this is converted to the distance L.

The drive circuit may be configured to include means for taking in vehicle speed information and inhibiting the optical axis angle adjustment operation when the vehicle speed is equal to or lower than a predetermined value. In other words, the device for controlling the optical axis angle of the headlight according to the present invention has an important effect of making the distant road surface visible, and the device controls the optical axis angle finely when the vehicle is running at low speed. Since it is not necessary to perform this control, the control may be prohibited during low-speed running, and the control may be enabled during high-speed running. The predetermined value of the vehicle speed is preferably selected and set to an appropriate value from, for example, a range of 5 km to 30 km per hour.

It is preferable that the drive circuit includes a low-pass filter having a cut-off frequency of a frequency sufficiently lower than the natural vibration frequency of the vehicle body in the front-rear direction in its arithmetic control system. This low-pass filter can be realized by averaging processing by software of the control circuit. With this configuration, it is possible to avoid a rapid change in the optical axis of the headlamp in order to follow the pitching of the vehicle body caused by the unevenness of the road surface.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment will be described with reference to the drawings.
FIG. 1 is an explanatory diagram of the operation principle of the present invention. 1 is a plan view, and the lower figure is a front view. FIG. 2 is an explanatory diagram of the operation principle of the present invention, and is an enlarged view of a front view headlight portion of FIG. FIG. 3 is a structural view of the headlamp according to the embodiment of the present invention, which is partially shown in section. FIG. 4 is an electrical block diagram of the apparatus according to the embodiment of the present invention. FIG. 5 is a flowchart for explaining the control logic provided in the control circuit of the apparatus according to the embodiment of the present invention.

The headlight 1 is mounted so that the angle of its optical axis with respect to the vehicle body can be adjusted. That is, the lamp body of the headlamp 1 is rotatably mounted around a shaft 11 provided at a lower portion thereof within a range of an angle φ, and an electric actuator 2 provided at an upper portion at an angular position within this angle range. Is configured to control the change. The shield beam lamp is connected to a lighting power supply. The transmitting / receiving element 5 of the radar means 4 is arranged below the lamp. The transmitting / receiving element 5 includes an infrared laser element, and irradiates an infrared laser beam having a very small solid beam angle toward a road surface obliquely downward in the traveling direction of the vehicle. Further, the transmitting / receiving element 5 includes a light receiving element that receives the reflected light of the irradiation light from the road surface.

The received signal of the reflected light is arithmetically processed by an arithmetic circuit inside the radar means 4 mounted on the vehicle, and a distance L from the transmitting / receiving element 5 to the road surface is calculated.
This is the value of the distance L shown in FIGS.

The value of the distance L is given to the drive circuit 3 together with the vehicle speed information of the vehicle. In the drive circuit 3, the control circuit 7 is controlled via an input interface circuit (I / O).
It is taken in. The control circuit 7 is a program control circuit, and a signal for driving the actuator 2 is transmitted via an output interface circuit (I / O) based on the calculation result.

FIG. 5 is a control flow chart of the control circuit 7.
It is. According to this control flowchart,
The measurement control operation of the example device will be described. When this device is started
Operation, or by a timer after startup
The initial setting switch closes. At this time, the radar means 4
Measure the distance L to the road surface in front of the ₀ 
Register as

When the vehicle speed is running (for example, 10 km / h)
Above), the distance L is repeatedly measured and averaged. This averaging process eliminates the effects of vehicle pitching and road surface irregularities. This averaged distance L
And the calculates the difference ΔL between the reference distance L _0, the ΔL controls the moving angle downwards if positive, to control the upward movement angle if negative. The magnitude of this movement angle can be changed according to the magnitude of ΔL, or can be a predetermined step amount. This is instructed to be supplied to the actuator 2 as a drive current. The actuator 2 physically changes the angle of the headlight 1 by the drive current. By repeating this operation, even if the angle of the vehicle body with respect to the road surface changes depending on the size and position of the load, the number of passengers, and the seating position, the angle of the optical axis A of the headlight with respect to the road surface is always kept constant.

Here, when the weight of the cargo or the passenger is large, the vehicle body itself is lowered, but the effect is small and is not considered in this embodiment.

As described above, the most significant feature of the present invention resides in that the angle of the headlight is controlled based on the distance L. This makes it possible for the first time to design a practical device. In other words, if the vehicle is controlled by the angle α with respect to the road surface, which is changed by the load, etc., and it is controlled to compensate for this, various difficult problems will be encountered, but as described above, the road surface is obliquely looked down. When the distance L to the road surface at that time is measured and used for angle control of the headlight, the angle control of the headlight can be easily realized. Although the technique for measuring the angle α becomes complicated, the distance L
The technology for measuring
If a technology for accurately measuring the distance to the subject and controlling the focal length is used, a device for measuring this distance L by a simple radar means can be designed inexpensively and with high accuracy even when mass-producing it. be able to.

[0028]

As described above, according to the present invention,
Even if the angle of the vehicle body relative to the road surface changes due to changes in the amount of cargo and its loading position, and the number of passengers and its seating position, the angle of the headlight's optical axis with respect to the vehicle body is automatically adjusted and controlled. Thus, it is possible to obtain a headlight and a control device for the headlight, in which the angle of the optical axis of the headlight with respect to the road surface is always kept constant, and the driver can always accurately recognize the state of the distant road surface.

[Brief description of the drawings]

FIG. 1 illustrates the principle of the present invention. The top is a plan view and the bottom is a front view.

FIG. 2 is an enlarged front view of the vicinity of a headlight for explaining the principle of the present invention.

FIG. 3 is a structural view of a headlight of the apparatus according to the embodiment of the present invention.

FIG. 4 is a block diagram of an electric system of the apparatus according to the embodiment of the present invention.

FIG. 5 is a flowchart of a control circuit operation of the device according to the embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Headlight 2 Actuator 3 Drive circuit 4 Radar means 5 Transceiver 6 Operation circuit 7 Control circuit 11 Headlight mounting axis

Claims (7)

[Claims] A headlight is mounted so that the angle of its optical axis with respect to the vehicle body can be adjusted, and includes a motorized actuator for changing the angle of the optical axis, and a drive circuit for driving the actuator. In a device for adjusting the optical axis angle of a lamp, radar means is provided, and the radar means is mounted so that its irradiation angle changes in conjunction with a change in the optical axis of the headlight, and is mounted on a road surface oblique to the traveling direction of the vehicle. And a calculating circuit for calculating and measuring a distance L from the transmitting and receiving element to the road surface, wherein the driving circuit has a distance measured by the radar means. An optical axis angle adjusting device for a headlamp, comprising a control circuit which takes in information of L and automatically controls the angle of the optical axis so that the distance L becomes constant. 2. The headlight optical axis angle adjusting device according to claim 1, wherein the transmitting / receiving element is attached to a lamp body of the headlight. 3. When one vehicle is provided with a plurality of headlights, a specific one headlight is configured as described in claim 2, and the other headlight is provided with the specific one headlight. An optical axis angle adjusting device provided with means for controlling the angle of the optical axis in conjunction with the optical axis angle adjusting device. 4. The headlight optical axis angle adjusting device according to claim 1, wherein said radar means uses infrared laser light. 5. The headlight optical axis angle adjusting device according to claim 1, wherein said radar means uses a light beam branched from a light emitted from the headlight and passed through a filter and a shutter. 6. The optical axis angle control device according to claim 1, wherein said drive circuit fetches vehicle speed information, and includes means for inhibiting an optical axis angle adjusting operation when the vehicle speed is equal to or lower than a predetermined value. 7. The drive circuit includes a low-pass filter having a cutoff frequency of a frequency sufficiently lower than a natural vibration frequency in the longitudinal direction of the vehicle body in an arithmetic control system thereof.
An optical axis angle control device as described in the above.