Method for adjusting a vehicle headlight via rear wheel track

Abstract

In various embodiments, a method for adjusting a vehicle headlight () via rear wheel track (S) is provided, comprising the steps of: determining a target distance between the vehicle (1) and a projection surface (7) at which a light beam (L2) indicating the rear wheel track would overlap with a light projection (L3) generated by the headlight on the projection surface (7), assuming that the headlight (2) is correctly aligned; positioning the vehicle (1) at the target distance in front of the projection surface (7); generating the light projection (L4) by means of the headlight (2); generating the light beam (L3) indicating the rear wheel track (S); adjusting the alignment of the headlight (2) such that its light projection (L4) overlaps with the light beam (L2) indicating the rear wheel track (S).

Description

The present invention relates to a method of adjusting a vehicle headlamp using the rear wheel lane.In modern vehicles, headlights based on an LED matrix are nowadays used, with which the light projection can be optimally adapted to various driving situations. In particular, the light projection can be dynamically adapted to the driving environment changing during the trip, for example by dimming the part of the light projection illuminating oncoming vehicles or by illuminating hazardous locations on the road edge particularly intensively or additionally.In order to be able to perform a correct dynamic adaptation of the light projection of the LED matrix headlights, it must be ensured that the position and orientation of the headlights, in particular with respect to the vehicle camera, are correct. Only then can the light projection be correctly adapted to the current driving environment on the basis of the image data supplied by the vehicle camera.The classic setting of the headlights with a light collection box can lead to the headlight (if then only accidentally) not lighting parallel to the direction of travel.Document DE 10 2014 003 370 A1 describes a checking device for checking the lamps and distance sensors of a vehicle. The test unit is aligned with the light or the distance sensor with a laser light source which is aligned at the front or rear axle of the vehicle at right angles thereto. The deviation of the alignment is measured on the basis of the deviation of the optical axis of the laser radiation from a predetermined marking which is arranged on a projection surface.Document DE102014113070A1 describes an adjusting device and a method for aligning a component on a vehicle. The component to be aligned can be, for example, a headlight or an axis. The alignment is effected with respect to a reference axis which represents a straight-ahead direction of travel of the vehicle.The object of the present invention can be seen in providing a method with which the headlights in a vehicle can be correctly adjusted without excessive effort.This object is achieved by means of the subject matter of the independent claim. Further preferred embodiments are found in the dependent claims.According to the present invention, a method for adjusting a vehicle headlight via rear wheel lane is provided. The setting can comprise both an initial setting or adjustment of the headlight by before the factory shipment of the vehicle and a renewed setting of the headlight within the scope of maintenance of the vehicle.In a first step, the method according to the invention comprises determining a setpoint distance between the vehicle and a projection surface at which a light beam indicating the rear wheel lane would overlap with a light projection on the projection surface generated by the headlight on the assumption that the headlight is correctly oriented. The determination can be carried out in particular by calculation in that the position of the headlight or of the associated light module in the vehicle, the position of a device generating the light beam, which measures the lane and can preferably be mounted on the rear wheel, and the previously or currently determined lane angle are geometrically related to one another. Based on these variables, the setpoint distance is calculated, in which the light beam indicating the track or the track angle indicates the setpoint position of the light projection of the correctly aligned headlight. The determination of the desired distance can be determined in a computer-aided manner on the basis of a design plan of the vehicle from which the required variables are known. The light projection of the headlight in the desired position or desired alignment can also be read into the vehicle model or be stored together with the latter. From these variables, the exact position or the distance to the overlap between the light projection of the correctly aligned headlight and the light beam indicating the track can be determined by calculation. The desired distance depends on the nominal toe angle and on the position of the headlights or the light mode within the vehicle.In calculating the desired distance, use is made of the fact that the lane at the rear wheels of a vehicle is generally set to to toe-in (i.e. wheels or wheel center planes are oriented slightly toward the vehicle center), since this generally results in a more stable driving behavior of the vehicle. Thus, at a predetermined distance in front of the vehicle-the desired distance-there is an overlap between the light beam indicating the lane and the light projection of the headlight in the desired position.In a further step, the method according to the invention comprises positioning the vehicle at a desired distance from a projection surface. This ensures that the light beam indicating the lane and passing beyond the front of the vehicle indicates the desired position of the light projection of a correctly oriented headlight on the projection surface--this case not necessarily being present, of course, in the actually observed vehicle and being brought about within the scope of the method described here.In a further step, the method according to the invention comprises generating the light beam indicating the rear wheel track.In a further step, which can take place before, together with or after the preceding step, the method according to the invention comprises generating the light projection by means of the headlight of the vehicle. This is the headlight to be aligned, which is also preferably arranged on the same side of the vehicle as the wheel with respect to which the light beam indicating the track is generated. The actually generated light projection can correspond, with regard to its light pattern or its light shape, to the modeled light projection that has been used in the context of the calculation of the desired distance.Finally, the method according to the invention comprises setting or adapting the alignment of the headlight in such a way that its light projection overlaps with the light beam indicating the track.In the method according to the invention, in a first phase, the lane set during vehicle production is used as a normative variable in order to determine the setpoint distance, in which the leg of the lane angle oriented toward the vehicle center overlaps with a light projection of the headlight, by calculation on this basis and with assumed correct setting / alignment of the headlights. In this case, geometric relationships are utilized in order to indicate the setpoint position for the lateral headlight setting by means of the rear wheel track. A correctly adjusted headlight is distinguished in that its light emission is aligned substantially parallel to the longitudinal axis of the vehicle. In a downstream phase, the overlap is then actually brought about or checked in real fashion, for example on a projection surface which is arranged at the setpoint distance in front of the vehicle.According to further embodiments of the method according to the invention, the method can further comprise determining the track of at least one of the rear wheels of the vehicle. The determination of the trace can thus be determined at the beginning of the method and thus be part of the method. Alternatively, the lane may be determined in advance, experimentally or from the design plan of the vehicle, and used to calculate the target distance. The track can be determined by measuring the associated track angle, which indicates how inclined the wheel is to the direction of travel when driving straight ahead, i.e. how much the wheel center axis is tilted with respect to the rear wheel axis. The track of a vehicle wheel is usually determined by a measuring device which at the same time also determines the camber of the wheel, that is to say the angle between the wheel center plane and a perpendicular to the roadway.According to further embodiments of the method according to the invention, the light beam indicating the rear wheel track can be generated when determining the rear wheel track. In other words, the track measurement and its indications by means of a light beam may coincide. In particular, the track can be generated by means of the measuring device measuring it, in particular by means of a laser beam. In this case, the beam generated can run parallel to the wheel center plane in the direction of the vehicle front and beyond the latter. The light beam thereby images a leg of the track angle. If necessary, the wheel can be dismounted in order to be able to apply the measuring device for lane determination directly to the wheel receptacle if it is to be ensured that inaccuracies from the sphere of the wheel can distort the result.According to further embodiments of the method according to the invention, the track of the rear wheel can be measured by means of a vertically self-leveling measuring device. The measuring device can be a wheel track laser, i.e. a device which uses a self-leveling laser in order to level the camber of the rear wheels. In other words, the measuring device can have a mechanism which displays the track of the corresponding rear wheel without the camber of the rear wheel distorting the track alignment displayed by means of the laser beam.According to further embodiments of the method according to the invention, this can be carried out for a headlight on the basis of the track of the rear wheel located on the same vehicle side.According to further embodiments of the method according to the invention, the generated light projection can have a vertical light strip or two light fields (e.g. light strips) which are at a distance from one another. Activating a special light projection of this type for the adjusting / adjusting process of the light module can help minimize the lateral error in bringing about the overlap. Thus, for the purpose of correct alignment of the light module of the headlight, in the first case the strip-like projection of the light beam indicating the track can be overlapped with the likewise strip-like light projection generated by the headlight. In the second case, the overlap can be brought about by positioning the strip-like projection of the light beam indicating the track centrally between the two light fields of the light projection generated by the headlight.According to further embodiments of the method according to the invention, the optical axis of the headlight can be marked in the generated light projection or can be recognizable therein. In order to simplify the recognition of the optical axis of the headlight, its position in the generated light projection can be indicated, for example, by a dark (light-free) region or by a bright (illuminated) region which is laterally bounded by dark regions.The features mentioned above and those still to be explained below can be used not only in the respectively specified combination, but also in other combinations or alone, without departing from the scope of the present invention.Further advantages and embodiments of the invention will become apparent from the following description of exemplary embodiments and the accompanying drawings. FIG. 1 illustrates an exemplary measurement scenario and an exemplary sequence of the method according to the invention. FIG. 2A shows the location of light markers of FIG. 1 relative to each other when the vehicle is standing too close to a projection surface. FIG. 2B shows the position of light markings from FIG. 1 relative to one another when the vehicle is at the desired distance from the projection surface.FIG. 1 illustrates an exemplary measurement scenario in which a vehicle 1 is standing on a ground 6, for example a roadway. The vehicle 1 has two headlights 2 arranged on the vehicle front side. Two front wheels 3 are mounted on a front axle and two rear wheels 4 are mounted on a rear axle.The method according to the invention for adjusting the headlights 2 of the vehicle 1 is explained here only with reference to the left headlight 2-it takes place analogally for the right headlight 2.The method begins with the determination of the track or the track angle S of at least one of the rear wheels 4 of the vehicle 1, wherein, in the determination, the track is displayed by means of a projection of a light beam L 2 beyond the front of the vehicle 1. For this purpose, a laser-supported toe measuring device 5 is arranged on each of the rear wheels 4, which measures the associated toe angle S. At the same time or downstream, the track measuring device 5 generates light beam L 2 indicating the track. The toe angle S is indicated only on the left side of the vehicle. The toe angle S is measured against an imaginary or actual boundary line L 1, which runs parallel to the longitudinal axis of the vehicle 1 and perpendicular to a projection surface 7 arranged in front of the vehicle 1.On the basis of the toe angle S, which can be determined directly or in advance, the desired distance is determined, in which the light beam L 2 overlaps with a light projection L 3 in front of the vehicle 1 generated by the corresponding headlight 2, on the assumption that the headlight 2 is correctly oriented.FIG. 1 outlines the case in which the distance d between the vehicle 1 and the projection surface 7 is still too small. Therefore, there is no overlap on the projection surface 7 in the designated area B between the light beam L 2 of the rear wheel track laser 5 and the light projection L 3 of the headlight 2 at its target position or target orientation. The relative position of the lines L2-L4 to each other is shown enlarged in FIG. 2A. In other words, the rear wheel track laser 5 is still illuminated too far to the left of the desired position of the light projection L3 of the headlight 2. during the adjusting operation the light projection L3 is not visible, since this represents a theoretical light projection when the headlight is mounted in its correct lateral desired orientation. The desired position of the actual light projection L 4 of the headlight 2 is displayed by the light beam L 2 indicating the lane, provided that the correct desired distance is present between the vehicle 1 and the projection surface 7.Starting from the scenario shown in FIG. 1, the distance d between vehicle 1 and projection surface 7 is set to the desired distance, wherein for this purpose the vehicle 1, the projection surface 7 or both can be moved. Then, the line L 2 indicating the lane overlaps the theoretical light projection L 3 of the correctly aligned headlight 2 in the region B of the projection surface is shown enlarged in FIG. 2B. As can be seen from the relative position of the actual light projection L 4 of the left headlight 2 with respect to the other two lines L 2, L 3, the left headlight 2 or its light module is aligned too much with respect to the vehicle center. On the basis of this, the actual adjustment process, which is indicated by the arrow J in FIG. 2B, can be carried out.During the setting of the correct alignment of the headlight 2, the light projection L 4 generated by the headlight 2 is shifted in the direction of the light beam L 2 indicating the track by corresponding adjustment of the light module within the headlight 2. The aim of the adjustment is that the actual light projection L 4 of the headlight 2 overlaps with the light beam L 2 of the rear wheel track laser 5 when the desired distance is set. Only when the overlap exists between the lines L 2 and L 4 is the headlight 2 correctly oriented.It should be noted that the line L 3, which represents the light projection of the headlight 2 at its desired position and runs parallel to the longitudinal axis of the vehicle 1, represents only an auxiliary line and is not visible during the setting process-therefore it is also represented by dashed lines. The "modeled" line L 3 is used as a calibration marking in the mathematical determination of the distance d between the vehicle 2 and the projection surface 7 in order to calculate the desired distance via its overlap with the light beam L 2 which is then also modeled and indicates the lane. If the distance d is then set to the calculated desired distance, it is known that the situation shown in FIG. 2B is present in which the projection of the light beam L 2 indicating the track indicates the light projection L 3 of a correctly aligned headlight, the latter itself not being visible.The method described here is distinguished in that the lateral alignment of the headlights 2 can be carried out without a light collection box and without any precisely provided markings on the projection surface 7. the precision is based on the calculated determination of the desired distance of a rear wheel track S determined within the scope of the method described here or in advance and on the generation of the light beam L 2 indicating the track. For the latter, measuring devices are available on the market which measure precisely and generate the light beam L2. The method can then be carried out on the basis of any desired, preferably planar projection surface 7, for example in front of a wall in a deep garage.

Claims

Method for adjusting a vehicle headlight (2) over rear wheel track (S), comprising the steps of: determining a desired distance between the vehicle (1) and a projection surface (7) in which a light beam (L2) indicating the rear wheel track would overlap with a light projection (L3) on the projection surface (7) generated by the headlight on the assumption that the headlight (2) is correctly aligned; positioning the vehicle (1) at the desired distance in front of the projection surface (7); generating the light projection (L4) by means of the headlight (2); generating the light beam (L2) indicating the rear wheel track (S); adjusting the orientation of the headlamp (2) such that its light projection (L4) overlaps with the light beam (L2) indicating the rear wheel lane (S).The method of claim 1, further comprising determining the rear wheel lane (S) of at least one of the rear wheels (4) of the vehicle (1).Method according to claim 2, wherein the light beam (L2) indicating the rear wheel lane (S) is generated in the determination of the rear wheel lane (S).Method according to claim 2 or 3, wherein the rear wheel lane (S) is measured by means of a vertically self-leveling measuring device (5).Method according to one of Claims 1 to 3, wherein the method is carried out for a headlight (2) on the basis of the rear wheel track (S) of the rear wheel (4) located on the same vehicle side.Method according to one of claims 1 to 5, wherein the generated light projection (L4) comprises a vertical light strip or two light fields located at a distance from one another.Method according to one of Claims 1 to 6, wherein the optical axis of the headlight is marked in the generated light projection or can be recognized therein.

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