Headlight control device

Abstract

The present invention suppresses glare by achieving an appropriate illumination range even in a vehicle having a high headlight ground level.　Provided is a headlight control device (11) for controlling a headlight unit, the headlight control device comprising: a vehicle (100) to which a headlight unit (21) is mounted; an inter-vehicular distance acquisition part (121) that acquires an inter-vehicular distance (d) to a preceding vehicle traveling in front of this vehicle; and an illumination control part (123) that displaces, when the inter-vehicular distance becomes shorter than a predetermined distance (L1), out of an illumination range of a low beam and an illumination range of a high beam set by the headlight unit, at least the illumination range of the low beam downward by a predetermined amount.

Description

Headlamp control device

[0001] The present invention relates to a headlamp control device that controls headlamps mounted on a vehicle.

[0002] Headlights mounted on vehicles project light emitted from a light source through an optical system such as a lens toward the front of the vehicle, and can switch between low beam and high beam as needed (see Patent Document 1). The illumination ranges of the low beam and high beam of the headlights are adjusted in accordance with the laws and regulations of the country in which the vehicle equipped with the headlights travels. Generally, the low beam is adjusted so that the upper end of the illumination range (cutoff line) is below the ground clearance of the headlight to prevent glare (dazzle) for preceding and oncoming vehicles, and the high beam is adjusted to illuminate a higher and farther distance than the low beam.

[0003] In a vehicle equipped with headlights, for example, when driving at night, high beams are normally used to ensure visibility for the driver, but when there are vehicles ahead, such as a preceding vehicle or an oncoming vehicle, or pedestrians, low beams are used to reduce glare to the vehicles ahead or pedestrians.

[0004] In addition, when light distribution control is performed on the headlights using ADB (Adaptive Driving Beam), the presence and location of vehicles or pedestrians ahead is identified while driving with high beams, and the headlight illumination range corresponding to the identified location is partially dimmed or turned off to reduce glare on vehicles ahead, etc.

[0005] JP 2019-43260 A

[0006] However, in vehicles with a high vehicle height or vehicles with headlights installed high above the ground, the headlights are relatively high above the ground, and the illumination range of the low beam and high beam is also high, which can easily cause glare to vehicles ahead.

[0007] As mentioned above, low beams limit the illumination range downward by adjusting the upper end of the illumination range to be below the ground clearance of the headlights. However, even with such low beams, glare may be generated on vehicles ahead if the headlights are relatively high above the ground. On the other hand, adjusting the low beam illumination range downward to offset the high ground clearance of the headlights may reduce the driver's visibility. Furthermore, if the headlight illumination range is located high, even if the ADB partially dims or turns off the headlight illumination range, glare may not be sufficiently suppressed.

[0008] The present invention addresses such a situation by optimizing the illumination range and suppressing glare even in vehicles with headlights that are high above the ground.

[0009] In order to solve the above problems, a light axis adjusting device according to the present invention has the following configuration: That is, one aspect of the present invention provides a headlight control device that controls a headlight unit that illuminates a predetermined range ahead of a host vehicle, the headlight control device including: an inter-vehicle distance acquisition unit that acquires the inter-vehicle distance between the host vehicle equipped with the headlight unit and a preceding vehicle traveling ahead of the host vehicle; and an illumination control unit that, when the inter-vehicle distance falls below a predetermined distance L1, displaces at least the low beam illumination range of the headlight unit downward by a predetermined amount out of the low beam illumination range and high beam illumination range of the headlight unit.

[0010] According to the optical axis adjusting device having such characteristics, even when the headlight is positioned high above the ground, it is possible to optimize the illumination range and reduce glare.

[0011] The present invention relates to a vehicle control system including a headlamp ECU, a headlamp control unit, a vehicle control system for a vehicle ...

[0012] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description, the same reference numerals in different drawings denote parts with the same functions, and duplicated descriptions in each drawing will be omitted as appropriate.

[0013] 1 and 2 , a headlamp ECU (headlamp control device) 11 according to an embodiment of the present invention controls a headlamp unit 21 (described later) attached to a vehicle 100, and functions as part of a vehicle control system 1 mounted on the vehicle 100. The vehicle control system 1 includes a plurality of on-board ECUs (Electronic Control Units) 10 that control various electronic devices required for driving the vehicle 100, and includes a headlamp ECU 11 and an external monitoring ECU 12 as one of the on-board ECUs 10.

[0014] The on-board ECUs 10, headlight ECU 11, external monitoring ECU 12, etc. are connected to each other via an on-board network 3 such as a controller area network (CAN) or a local interconnect network (LIN) so as to be able to communicate with each other, and are also connected to a central gateway (CGW) 4 as a relay device to form a vehicle control system 1. The on-board ECUs 10, headlight ECU 11, and external monitoring ECU 12 are connected to the electronic devices that they control, and control the operation of the connected electronic devices based on information (data) acquired from the on-board network 3. Furthermore, each on-board ECU outputs information indicating the operating state and other status of the connected electronic devices to the on-board network 3.

[0015] Each of the on-board ECUs 10, headlamp ECU 11, and external monitoring ECU 12 may be configured to include, for example, a processor such as a central processing unit (CPU) or a micro processing unit (MPU), electrical circuits, and storage elements such as a random access memory (RAM) or a read-only memory (ROM). Some or all of the operations performed by the on-board ECUs may also be implemented by hardware such as an application specific integrated circuit (ASIC), a field-programmable gate array (FPGA), or a graphics processing unit (GPU). In the following description, detailed descriptions and illustrations of electronic devices not directly involved in the operation of the headlamp ECU 11, the on-board ECU 10, etc. will be omitted.

[0016] The headlamp ECU 11 is connected to a headlamp unit 21 provided in front of the vehicle 100 and controls the headlamp unit 21. The headlamp ECU 11 is also connected to a light axis adjustment unit 22 that adjusts the light axis of the headlamp unit 21 in accordance with instructions from the headlamp ECU 11. Details of the headlamp ECU 11 will be described later.

[0017] The headlamp units 21 are typically provided on the left and right sides of the front of the vehicle, and include a low beam unit 21A that emits a low beam called a passing headlamp, and a high beam unit 21B that emits a high beam called a driving headlamp. The low beam unit 21A and the high beam unit 21B each include a light source such as an LED, a reflector that guides the light emitted from the light source to the front of the vehicle 100, and a lens that irradiates the light emitted from the light source in a predetermined light distribution pattern (none of which are shown).

[0018] In order to reduce glare on vehicles and pedestrians around the vehicle 100, the low beam unit 21A illuminates an area lower than the high beam illumination area and closer to the vehicle 100. Therefore, the low beam illumination area of ​​the low beam unit 21A is set so that it is possible to check for potential obstacles to the traveling of the vehicle 100, such as preceding vehicles and pedestrians located approximately 40 m ahead of the vehicle 100.

[0019] High beam unit 21B irradiates light at a greater illuminance than the low beam illumination range to increase the driver's visibility while driving vehicle 100. Therefore, the illumination range of the high beam emitted by high beam unit 21B is set so that the driver can see any obstacles that may be present in the driving of vehicle 100, such as preceding vehicles or pedestrians located approximately 100 meters ahead of vehicle 100.

[0020] The optical axis adjustment unit 22 includes a drive mechanism such as an electric actuator, and adjusts the optical axis of the low beam unit 21A and the optical axis of the high beam unit 21B by operating the drive mechanism in accordance with instructions from the headlamp ECU 11. The optical axis adjustment unit 22 swings the optical axis of the low beam unit 21A and the optical axis of the high beam unit 21B up and down, changing the angle of each optical axis relative to the horizontal direction, thereby displacing each illumination range.

[0021] The external monitoring ECU 12 constitutes, for example, a part of an ADAS (Advanced Driver-Assistance Systems) that assists the driving of the vehicle 100, and monitors the environment outside the vehicle 100 using a group of sensors including a camera 23, a radar 24, and various other sensors included in the ADAS. That is, the external monitoring ECU 12 outputs, as surrounding information to the in-vehicle network 3, images and various data acquired from the group of sensors described above, or moving objects, structures, road shapes, etc. including pedestrians around the vehicle and other vehicles around the vehicle that are understood from these images and various data, as well as the distances and positional relationships between these and the vehicle.

[0022] The camera 23 is provided, for example, above the windshield of the vehicle 100 and in the center in the vehicle width direction, and captures an image of a predetermined range in front of the vehicle 100. The radar 24 is provided at multiple locations on the vehicle 100, and measures the distance and direction to objects in front of, behind, and to the sides of the vehicle 100, such as other vehicles, pedestrians, and structures, by transmitting radio waves of a predetermined wavelength and receiving the reflected waves.

[0023] (Headlamp ECU) The following describes the headlamp control device, ie, the headlamp ECU 11. The headlamp ECU 11 controls the headlamp unit 21 by referring to information acquired from the above-described in-vehicle ECUs via the in-vehicle network 3.

[0024] As shown in Fig. 2, the headlamp ECU 11 includes a CPU (Central Processing Unit) 111, a ROM 112, and a RAM 113. The CPU 111 executes various processes based on programs stored in the ROM 112. In this embodiment, the CPU 111 loads the programs stored in the ROM 112 into a memory such as the RAM 113 and executes them, thereby functioning as an inter-vehicle distance acquisition unit 121, a light distribution control unit 122, and an illumination control unit 123 shown in Fig. 2. The inter-vehicle distance acquisition unit 121 and the illumination control unit 123 will be described below.

[0025] The inter-vehicle distance acquisition unit 121 acquires the inter-vehicle distance d between the vehicle 100 and a preceding vehicle traveling ahead of the vehicle 100. The preceding vehicle includes an oncoming vehicle traveling in the opposite direction to the traveling direction of the vehicle 100, and a preceding vehicle traveling ahead of the vehicle 100 in the same traveling direction as the vehicle 100.

[0026] The inter-vehicle distance acquisition unit 121 can acquire, for example, from the external monitoring ECU 12, the inter-vehicle distance d, which is the distance between the vehicle 100 and a preceding vehicle, calculated based on an image of a predetermined range ahead of the vehicle 100 captured by the camera 23, or the inter-vehicle distance d measured based on transmitted waves and received waves by the radar 24. The inter-vehicle distance acquisition unit 121 may acquire the image captured by the camera 23 via the external monitoring ECU 12 and perform predetermined image processing on the image to acquire the inter-vehicle distance d.

[0027] The light distribution control unit 122 sets light distribution patterns for the low beam unit 21A and the high beam unit 21B to illuminate their respective illumination ranges, and outputs drive signals according to the set light distribution patterns to the headlamp unit 21. The light distribution control unit 122 can also perform variable light distribution control known as ADB (Adaptive Driving Beam) (hereinafter referred to as ADB control). For example, when the vehicle 100 is traveling with its high beams illuminated and a vehicle ahead is present, the light distribution control unit 122 uses ADB control to set a light distribution pattern such that a range of the illumination range of the high beam unit 21B corresponding to the position of the vehicle ahead is partially dimmed or blocked.

[0028] When the inter-vehicle distance d between the vehicle 100 and the vehicle ahead, acquired by the inter-vehicle distance acquisition unit 121, becomes equal to or less than a certain distance, i.e., when the inter-vehicle distance d becomes less than the predetermined distance L1, the illumination control unit 123 controls the headlamp unit 21 to shift the illumination range downward. At this time, the illumination control unit 123 shifts only the low beam illumination range or both the low beam illumination range and the high beam illumination range downward by a predetermined amount.

[0029] Regardless of whether the aforementioned ADB control is being performed or not, when the inter-vehicle distance d between the vehicle 100 and the vehicle ahead falls below a predetermined distance L1, the illumination control unit 123 controls the headlight unit 21 to displace the illumination range downward.

[0030] The above-mentioned predetermined amounts, i.e., the amounts of displacement of the low beam illumination range and the high beam illumination range, can be determined in advance based on the height above the ground of the headlamp unit 21 on the vehicle 100, etc., and can be stored in the ROM 112 of the headlamp ECU 11. In addition, the illumination control unit 123 can acquire the height above the ground of the headlamp unit 21 each time the vehicle is traveling, based on the mounting position of the headlamp unit 21 on the vehicle 100, information obtained from a vehicle height sensor (not shown), etc., and calculate the amount of displacement of each illumination range so that the low beam illumination range and the high beam illumination range become appropriate illumination ranges.

[0031] The illumination control unit 123 can displace each illumination range by adjusting the optical axes of the low beam unit 21A and the high beam unit 21B. In this case, the illumination control unit 123 determines an adjustment amount for each of the optical axes of the low beam unit 21A and the high beam unit 21B according to the amount of displacement of each illumination range, and outputs a drive signal indicating each adjustment amount to the optical axis adjustment unit 22.

[0032] In addition, when the inter-vehicle distance d falls below a predetermined distance L1, the illumination control unit 123 displaces only the low beam illumination range or both the low beam illumination range and the high beam illumination range downward, and then controls the headlight unit 21 to return each illumination range to its position before displacement in the following cases:

[0033] When the preceding vehicle is a preceding vehicle traveling ahead of vehicle 100 in the same traveling direction as vehicle 100, and the inter-vehicle distance d between the preceding vehicle and vehicle 100 exceeds a predetermined distance L2, the illumination control unit 123 returns each illumination range to its position before the displacement. When the preceding vehicle is an oncoming vehicle of vehicle 100, the illumination control unit 123 returns each illumination range to its position before the displacement after vehicle 100 and the oncoming vehicle have passed each other. In this manner, glare on vehicles ahead of vehicle 100 and the like is suppressed, while ensuring visibility for the driver of vehicle 100.

[0034] The control process for the headlamp unit 21 by the headlamp ECU 11 configured as above will be described below with reference to the flowchart in Fig. 3. The vehicle 100 travels in a dark environment, such as at night, while emitting a low beam or a high beam from the headlamp unit 21 in accordance with the light distribution pattern set by the light distribution control unit 122 of the headlamp ECU 11.

[0035] At this time, in the vehicle 100, the camera 23 captures images ahead of the vehicle 100 at a predetermined cycle, and the radar 24 measures the positional relationship and distance to other vehicles (including the vehicle ahead) and pedestrians present around the vehicle 100 at a predetermined cycle, and outputs the results to the external monitoring ECU 12. Based on the image output from the camera 23 or the measurement results by the radar 24, if there is another vehicle ahead of the vehicle 100, the external monitoring ECU 12 outputs an inter-vehicle distance d indicating the distance between the vehicle 100 and the vehicle ahead.

[0036] In the headlamp ECU 11, the inter-vehicle distance acquisition unit 121 acquires the inter-vehicle distance d from the external monitoring ECU 12 via the in-vehicle network 3 (step S11), and monitors whether the inter-vehicle distance d is less than a predetermined distance L1 (step S12). If the inter-vehicle distance d is less than the predetermined distance L1 (YES in step S12), the inter-vehicle distance acquisition unit 121 notifies the illumination control unit 123 of this fact, and the illumination control unit 123 controls the headlamp unit 21 to shift the illumination range downward (step S13).

[0037] At this time, when only the low beam is emitted by the low beam unit 21A, the headlamp unit 21 displaces the low beam illumination range downward. Also, when the high beam is emitted while the illumination range is partially shaded by the ADB control, the headlamp unit 21 may displace the high beam illumination range downward.

[0038] The inter-vehicle distance acquisition unit 121 continues to acquire the inter-vehicle distance d between the vehicle 100 and the preceding vehicle even after shifting the illumination range downward (step S14). Based on the inter-vehicle distance d, it is determined whether the vehicle 100 has passed the preceding vehicle (step S15). If the vehicle 100 has not passed the preceding vehicle (NO in step S15), it is determined whether the inter-vehicle distance d exceeds a predetermined distance L2 (step S16). If the inter-vehicle distance d exceeds the predetermined distance L2 (YES in step S16) or if the vehicle 100 has passed the preceding vehicle (YES in step S15), the illumination control unit 123 is notified of this, and the illumination control unit 123 controls the headlamp unit 21 to return the illumination range that has been shifted downward to the illumination range before the shift (step S17).

[0039] (Modification) A light source in which a plurality of light-emitting elements are arranged in a matrix may be used as the light source for the low beam unit 21A and the high beam unit 21B. In this case, the illumination control unit 123 outputs a drive signal to the headlamp unit 21 that indicates whether to turn on or off each light-emitting element for the low beam unit 21A and the high beam unit 21B in accordance with the light distribution pattern set for each illumination range.

[0040] Furthermore, when displacing each illumination range, the illumination control unit 123 displaces the low beam illumination range and the high beam illumination range by controlling the lighting state of each light-emitting element according to the amount of displacement. That is, the illumination control unit 123 displaces the low beam illumination range and the high beam illumination range by changing the light distribution patterns of the low beam unit 21A and the high beam unit 21B set by the light distribution control unit 122.

[0041] Specifically, the illumination control unit 123 sets a corrected light distribution pattern in which, among the multiple light-emitting elements of the light source of the low beam unit 21A and the high beam unit 21B, the light-emitting elements that illuminated the upper part of the illumination range in the light distribution pattern before the displacement are changed from a lit state to a non-lit state, and the light-emitting elements that are located further below the light-emitting elements that illuminated the lower part of the illumination range are changed from a non-lit state to a lit state.

[0042] In this way, the illumination control unit 123 sets a corrected light distribution pattern so that the low beam illumination range and the high beam illumination range are downward, and can displace each illumination range by controlling the headlight unit 21 based on this corrected light distribution pattern.

[0043] According to the above-described embodiment and its variants, when the inter-vehicle distance d between the vehicle itself, i.e., vehicle 100, and the vehicle ahead falls below a predetermined distance L1, at least the low beam illumination range is displaced downward, so that even in vehicles with headlights that are high above the ground, the illumination range can be optimized to reduce glare for oncoming or preceding vehicles.

[0044] If the vehicle ahead is an oncoming vehicle, the illumination range is displaced downward, and then when vehicle 100 and the oncoming vehicle pass each other, the displaced illumination range is returned to its original state, thereby ensuring visibility for the driver of vehicle 100. Similarly, if the vehicle ahead is a leading vehicle, after the illumination range is displaced downward, when the inter-vehicle distance d exceeds predetermined distance L2 and a sufficient distance is secured so that the low beam or high beam illumination of vehicle 100 does not cause glare to the leading vehicle, the displaced illumination range is returned to its original state, thereby ensuring visibility for the driver of vehicle 100.

[0045] Although the embodiments of the present invention have been described in detail with reference to the drawings, the specific configurations are not limited to these embodiments, and the present invention also includes design changes within the scope of the present invention. Furthermore, the above-described embodiments can be combined by utilizing each other's technologies as long as there are no particular contradictions or problems in their purposes, configurations, etc.

[0046] 1: Vehicle control system, 3: In-vehicle network, 11: Headlight ECU, 12: External monitoring ECU, 21: Headlight unit, 21A: Low beam unit, 21B: High beam unit, 22: Optical axis adjustment unit, 23: Camera, 24: Radar, 121: Inter-vehicle distance acquisition unit, 122: Light distribution control unit, 123: Irradiation control unit

Claims

1. A headlamp control device that controls a headlamp unit that illuminates a predetermined range ahead of a host vehicle, an inter-vehicle distance acquisition unit that acquires an inter-vehicle distance between a host vehicle equipped with the headlamp unit and a preceding vehicle traveling in front of the host vehicle; an illumination control unit that, when the inter-vehicle distance falls below a first distance, displaces at least the low beam illumination range of the headlamp unit downward by a predetermined amount among the low beam illumination range and the high beam illumination range; a light distribution control unit that partially dims or blocks a range of the high beam illumination corresponding to the position of a forward vehicle, When the inter-vehicle distance falls below a first distance, the illumination control unit displaces at least the low beam illumination range of the headlight unit downward by a predetermined amount, regardless of the operation of the light distribution control unit.

2. The headlamp control device according to claim 1 , wherein the illumination control unit adjusts an optical axis of the headlamp unit to change the illumination range of the low beam.

3. The headlamp unit includes a light source in which a plurality of light-emitting elements are arranged in a matrix, The headlamp control device according to claim 1 , wherein the illumination control unit controls the lighting state of the light-emitting element to change the illumination range of the low beam.

4. When the forward vehicle is a preceding vehicle traveling ahead of the host vehicle in the same traveling direction as the host vehicle, The irradiation control unit 2. The headlight control device according to claim 1, wherein when the inter-vehicle distance between the preceding vehicle and the subject vehicle exceeds a second distance, the low beam illumination range and the high beam illumination range of the headlight unit that have been displaced downward are returned to their positions before the displacement.

5. When the preceding vehicle is an oncoming vehicle of the host vehicle, The irradiation control unit 2. The headlight control device according to claim 1, wherein after the host vehicle and the oncoming vehicle have passed each other, the illumination ranges of the low beam and the high beam of the headlight unit that have been displaced downward are returned to their positions before the displacement.