How to Adjust the Headlight System

Abstract

The invention relates to a method (1) for adjusting an automated headlight system (8) of a motor vehicle (3), where the headlight system (8) comprises a headlight for generating a low beam and a control device for adjusting a lower cut-off line (9) of the low beam. The method comprises the following steps in the following order: - calculating an elevation gradient (5) from an extract (4) of the digital height model (2), - determining two next forward turning points (6a, 6b) from the elevation gradient (5); - determining and characterizing the average path position (7) based on the turning points (6a, 6b), - adjusting the lower cut-off line (9) to the midpoint (10) of the mean path position (7) at least when the first turning point (6a) is reached. is executed. The invention also relates to an automated headlight system (8) of a motor vehicle (3) for carrying out this method (1).

Description

[Technical field]

[0001] The present invention relates to a method for adjusting an automated headlight system of a motor vehicle, the headlight system having at least two headlights for generating a low beam and a control device for adjusting a lower cut-off line of the low beam. The present invention also relates to an automated headlight system for a motor vehicle. [Background technology]

[0002] In modern automobiles, automatic or adaptive headlight systems with headlights generating low beams are available and often used. The headlight system determines the road path by means of camera-based lane recognition, on the basis of which the low beam can be adapted to the road path by means of the headlight mechanism or servo motors. The headlight system is thereby designed to steer, and the low beam can be adjusted horizontally to the road. Vertical adjustment of the low beam of the headlight can be performed in a similarly camera-based manner by adapting the light-dark boundary of the low beam to the boundaries of objects, for example the vehicle ahead. In this case, it is disadvantageous that steep slopes of the road cannot be detected. For example, when going over a rounded mountain peak, the headlight system will illuminate the sky, since the camera does not cover or cannot detect the slope of the road.

[0003] Steering sensor-based headlight systems are also known from the prior art. In steering sensor-based headlight systems, the road inclination is evaluated by means of a steering angle sensor in the steering column and the headlights or low beam are adjusted accordingly. However, a predictive adjustment of the headlights is not possible in steering sensor-based headlight systems, since the input of the steering angle sensor is required for the adjustment. Furthermore, in this case, only the movement of the vehicle about the Z axis is evaluated, and therefore adjustments regarding pitching moments cannot be taken into account.

[0004] Headlight systems that perceptually adjust the headlights are also known. Approaches are known for adapting the low beam to the road inclination depending on the situation, which are based, for example, on lane recognition or free space recognition. Today's headlight systems are also equipped with radar and lidar systems for adapting the low beam to the road inclination. In that case, sensors are used to determine the surroundings of the vehicle. However, the disadvantage is that the sensor has a FOV (Field Of View) and therefore cannot detect the crossing of rounded mountain peaks.

[0005] For example, US Patent No. 5,999,633 discloses a method in which the headlight coverage is detected from a 3D profile of the road. The 3D profile is created on a vehicle basis, where a pattern is projected onto the road using the headlights and recorded by a camera. From the distortion of the pattern, the 3D profile of the road ahead can be detected and the headlights controlled accordingly. [Patent Document 1] DE102018100738A1

[0006] US Pat. No. 5,399,433 discloses a method for adjusting headlights perpendicular to the road path, using information on the road topology from a digital map for the adjustment. US Pat. No. 5,399,433 discloses a method for recognizing the pitching movement of the vehicle and for compensating for the resulting change in the light-dark boundary. US Pat. No. 5,399,433 discloses a method for controlling headlights depending on a calculated visibility difference between low and high beams. Topographical data can be taken into account in the calculation of the visibility difference. [Patent Document 2] DE102018219604A1 [Patent Document 3] DE102017005019A1 [Patent Document 4] DE102014225513A1 Summary of the Invention [Problem to be solved by the invention]

[0007] It is therefore an object of the present invention to provide an improved, or at least an alternative, method for adjusting an automated headlight system, as well as an improved, or at least an alternative embodiment of an automated headlight system, which overcomes the above-mentioned drawbacks. [Means for solving the problem]

[0008] The above object is achieved according to the invention by the subject matter of the independent claims. Advantageous embodiments are the subject matter of the dependent claims.

[0009] The method according to the invention is intended for adjusting an automated headlight system of a motor vehicle, the headlight system then having at least two headlights for generating low beams and a control device for adjusting the lower cut-off line of the low beams. In the method, firstly, by mapping, an elevation gradient of a route ahead of the motor vehicle is calculated from an extract of a digital height model. In the method, then, from the elevation gradient, two next turning points ahead are determined, which lead to a tilt of the motor vehicle around the Y axis of the motor vehicle. Then, in the method, an average path position is determined and characterized based on the two next turning points ahead. Then, in the method, the lower cut-off line of the low beams of the headlight system is adjusted to the midpoint of the average path position when at least the first turning point ahead is reached.

[0010] In the method according to the invention, a digital height model (DHM) or a digital terrain model (DGM) is used, which allows the headlights of the headlight system, and thus the low beam, to be predictively and adaptively adjusted to the inclination of the vehicle about the Y axis when passing the first turning point to be traversed. In particular, the elevation gradient and the average route position can be calculated or determined already before the first turning point to be traversed is reached. As a result, the lower cut-off line of the low beam can be quickly adjusted at least when the first turning point ahead is reached, and the road ahead can be sufficiently illuminated when passing or passing the first turning point to be traversed. The turning point can be formed, for example, by a mountain peak, or a ridge, or a mountain valley, or a mountain crest.

[0011] Advantageously, in the method according to the invention, a digital height model or digital terrain model (DGM) is used. In that case, the digital height model contains data that image the topography in three dimensions and with an accuracy of less than 10 cm worldwide. In that case, the digital height model is generated periodically, for example once a day, by a satellite-based system. This allows the method according to the invention to be used country-independently. Furthermore, the method according to the invention is independent of the weather and cloud conditions and generally of the light conditions around the vehicle, in comparison with conventional methods based on optical data acquisition. Furthermore, the method is independent of miscalibrations, for example external and / or internal deviations in the optical sensors, and does not require a recalibration of the headlight system. In addition, the method according to the invention is independent of the equipment of the vehicle and does not require a special set of sensors. In addition, the method according to the invention increases driving comfort and driving safety by adjusting the cut-off line of the low beam of the headlight system according to the situation and predictively.

[0012] Advantageously, it can be provided that, before calculating the elevation gradient, the following steps are carried out in the following order: determining a digital height model of the vehicle's surroundings, locating the vehicle in a superior coordinate system, and providing an extract of the digital height model of the vehicle's surroundings, related to the route ahead of the vehicle. As already mentioned above, in this method a digital height model or a digital terrain model is used. Advantageously, it can be provided that when locating the vehicle, the vehicle is located by an internal GPS system (GPS: Global Positioning System) and / or a GCP system (GCP: Ground Control Point).

[0013] Advantageously, the digital height model can be designed to be determined by SAR measurements (SAR: Synthetic Aperture Radar), making the method independent of weather and cloud conditions and generally of the light conditions in the vicinity of the vehicle.

[0014] Advantageously, when determining the average path position, it can be provided that this is determined by an intersection analysis. In that case, the average path position can be determined as a straight line passing through the next two turning points ahead. Advantageously, when characterizing the average path position, it can be provided that the inclination angle of the path position relative to a horizontal or vertical line is determined. Advantageously, when adjusting the lower cut-off line of the low beam, it can be provided that the inclination angle of the average path position is transmitted to a control device of the headlight system.

[0015] Advantageously, it can be provided that the adjustment of the low beam lower cut-off line of the headlight system takes place as a function of the tilt angle before the first turning point to be traversed in time is reached or when the first turning point to be traversed in time is reached. For this purpose, a function graph can be provided for adjusting the headlight of the headlight system and thus the low beam lower cut-off line as a function of the tilt angle.

[0016] If the tilt angle is large, the vehicle will be tilted significantly about the Y axis when passing the first turning point to be traversed, and the headlights can be preconditioned or prealigned before reaching the first turning point in time. This allows the inertia of the headlight motor system to be taken into account. In that case, the preconditioning or prealignment can be performed in a short interval before reaching or passing the first turning point to be traversed, so that the illumination of the road is not adversely hindered before the first turning point to be traversed. If the tilt angle is small, the vehicle will be tilted only slightly about the Y axis when passing the first turning point to be traversed, and the headlights can be directly aligned when reaching or passing the first turning point to be traversed. In other words, in this case, the preconditioning or prealignment of the headlights can be omitted.

[0017] Advantageously, it can be provided that when the elevation gradient is calculated, the frequency of calculating the average route position from this elevation gradient is determined. In that case, the calculation can be made depending on the change profile of the route ahead. If the route ahead has multiple turning points that cause tilting around the Y axis, the average route position is calculated more frequently. If the route ahead has fewer turning points that cause tilting around the Y axis, the average route position is calculated less frequently. This is the case, for example, when the route extends over a monotonous or flat section. To determine the frequency, for example, the Fourier transform of the elevation gradient can be taken into account.

[0018] The invention also relates to an automated headlight system for a motor vehicle, which in that case has at least two headlights for generating a low beam and a control device for adjusting the lower cut-off line of the low beam. According to the invention, the headlight system is designed to carry out the above-mentioned method.

[0019] Further important features and advantages of the invention emerge from the dependent claims, the drawing and the corresponding description based on the drawing.

[0020] It is to be understood that the features listed above, and further described below, can not only be used in the respective combinations indicated, but can also be used in other combinations or alone, without departing from the scope of the present invention.

[0021] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention are illustrated in the drawings and described in more detail below, where like reference numbers indicate identical or similar or functionally identical elements. The drawings show, in schematic form, [Brief description of the drawings]

[0022] [Figure 1] 1 shows a schematic flow chart of a method according to the present invention. [Diagram 2] 1 is a diagram visualising the steps of the method according to the invention; [Diagram 3] 1 is a diagram visualising the steps of the method according to the invention; [Figure 4] 1 is a diagram visualising the steps of the method according to the invention; [Diagram 5] 1 is a diagram visualising the steps of the method according to the invention; [Figure 6] 1 is a diagram visualising the steps of the method according to the invention; [Figure 7] 1 is a diagram visualising the steps of the method according to the invention; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0023] Figure 1 shows a flow chart of method 1 according to the invention. The individual steps of method 1 are visualised in figures 2 to 7. The individual steps of method 1 and the visualisations in figures 2 to 7 are explained in more detail below.

[0024] 1, in a first step VS1 of the method 1, a digital height model 2 or a digital terrain model of the surroundings of the vehicle 3 is determined. The digital height model 2 is determined by SAR measurements.

[0025] 1 and 2, in a second step VS2 of the method 1, localization of the vehicle 3 is performed in a higher coordinate system. In that case, localization of the vehicle 3 can be performed by an internal GPS system and / or a GCP system.

[0026] 1 and 3, a third step VS3 of the method 1 involves the provision and downloading of an excerpt 4 from a digital elevation model 2 of the surroundings of the vehicle 3, related to the route 11 ahead of the vehicle 3.

[0027] 1 and 4, in a fourth step VS4 of the method 1, the calculation of the elevation gradient 5 of the route ahead of the vehicle 3 is performed by mapping from the extract 4 of the digital height model 2. Furthermore, in a fourth step VS4, from the elevation gradient 5, the determination of the next two turning points 6a, 6b ahead, which lead to the inclination of the vehicle 3 around its Y axis, is performed. In Fig. 5, the elevation gradient 5 calculated in step VS4 and the turning points 6a and 6b calculated in step VS4 are shown.

[0028] 1, in a fifth step VS5 of method 1, the frequency with which to calculate the average route position 7 is determined. This frequency can be achieved, for example, by a Fourier transform of the elevation gradient 5. If the route ahead has multiple turning points, the average route position 7 is recalculated more frequently. If the route ahead has a small number of turning points, the average route position 7 is recalculated less frequently.

[0029] 1 and 6, in a sixth step VS6 of the method 1, a determination and characterization of the average path position 7 is performed based on the turning points 6a and 6b. The determination of the average path position 7 can be performed by an intersection analysis. In that case, the average path position 7 can be determined as a straight line passing through the turning points 6a, 6b. Furthermore, the inclination angle of the average path position 7 with respect to the horizontal and the midpoint 10 are calculated. The midpoint 10 can be calculated, for example, as the intersection of the average path position 7 with the actual path position or the actual road. Alternatively, the midpoint 10 can be set in the middle between the two turning points 6a and 6b.

[0030] With reference to FIG. 1, in a seventh step VS7 of the method 1, a transmission of the inclination angle of the average path position 7 to a control unit of a headlight system 8 of the motor vehicle 3 takes place.

[0031] 1 and 7, in an eighth step VS8 of the method 1, the lower cut-off line 9 of the low beam of the headlight system 8 is adjusted to the midpoint 10 of the mean path position 7. This adjustment is dependent on the inclination angle of the mean path position and in this embodiment is already performed before the first forward turning point 6a is reached.

[0032] 1, in method 1, the second step VS2 is performed after the eighth step VS8. The transition speed from the eighth step VS8 to the second step VS2 depends on the frequency of the fifth step VS5.

Claims

1. A method (1) for adjusting an automated headlight system (8) of a motor vehicle (3), said headlight system (8) having at least two headlights for generating a low beam and a control device for adjusting a lower cut-off line (9) of said low beam, The following steps, in the following order: - calculating, by mapping, the elevation gradient (5) of the route (11) ahead of said vehicle (3) from an extract (4) of a digital height model (2), - determining, from said elevation gradient (5), the next two forward turning points (6a, 6b) which lead to a tilt of said vehicle (3) about its Y axis; - determining and characterising the mean path position (7) based on the next two forward turning points (6a, 6b); - adjusting the lower cut-off line (9) of the low beam of the headlight system (8) to a midpoint (10) of the mean path position (7) when at least a first turning point (6a) in front of the vehicle is reached, The method comprising:

2. Before calculating the elevation gradient (5), the following steps are carried out in the following order: - determining said digital height model (2) of the surroundings of said vehicle (3), - locating said vehicle (3) in a superior coordinate system, - providing said excerpt (4) of said digital elevation model (2) of the surroundings of said vehicle (3) related to the route (11) ahead of said vehicle (3), 2. The method of claim 1, wherein:

3. 3. A method according to claim 2, characterized in that when locating the vehicle (3), the vehicle is located by means of an internal GPS system and / or a GPS system.

4. Method according to claim 2 or 3, characterized in that the digital height model (2) is determined by SAR measurements.

5. 5. A method according to any one of claims 1 to 4, characterized in that, when determining the average path position (7), the average path position is determined by means of an intersection analysis.

6. 6. A method according to claim 1, characterized in that when characterising the mean path position (7), an angle of inclination of the mean path position (7) relative to a horizontal or vertical line is determined.

7. 7. The method according to claim 6, characterized in that when adjusting the lower cut-off line (9) of the low beam, the inclination angle of the mean path position (7) is transmitted to the control device of the headlight system (8).

8. 8. The method according to claim 6 or 7, characterized in that the adjustment of the lower cut-off line (9) of the low beam of the headlight system (8) takes place in dependence on the tilt angle in time before reaching the first turning point (6a) to be traversed, instead of when the at least first turning point (6a) in front is reached.

9. 9. A method according to any one of claims 1 to 8, characterized in that, once the elevation gradient (5) is calculated, the frequency with which a new average route position (7) is calculated is determined from the elevation gradient.

10. An automated headlight system (8) for a motor vehicle (3), said headlight system (8) comprising at least two headlights for generating a low beam and a control device for adjusting a lower cut-off line (9) of the low beam, The automated headlight system (8), characterized in that it is designed to carry out the method (1) according to any one of claims 1 to 9.

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