Control device for vehicular lamp, vehicular lamp system, and control method for vehicular lamp

Abstract

To provide a technique capable of more highly accurately performing automatic leveling control for adjusting an optical axis position of a vehicular lamp by acquiring an inclination angle of a vehicle with respect to a horizontal plane from an inclination detection device.SOLUTION: Emission control units 228L and 228R include: reception units 228L1 and 228R1 for receiving an inclination angle of a vehicle 300 with respect to a horizontal plane from an inclination detection device; control units 228L2 and 228R2 configured to generate a control signal for instructing adjustment of an optical axis position of a vehicular lamp with respect to change in the inclination angle while the vehicle is stopped and generate a control signal for instructing avoidance of generation of the control signal or maintenance of the optical axis position with respect to change in the inclination angle while the vehicle is traveling; and transmission units 228L3 and 228R3 for transmitting the control signal to a leveling control unit 236 of the vehicular lamp.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a control device for vehicle lamps, a vehicle lamp, and a method for controlling a vehicle lamp, and more particularly to a control device for vehicle lamps, a vehicle lamp, and a method for controlling a vehicle lamp used in automobiles and the like.

Background Art

[0002] Conventionally, auto-leveling control is known in which the optical axis position of a vehicle headlamp is automatically adjusted according to the inclination angle of a vehicle to change the irradiation direction. Generally, in auto-leveling control, a vehicle height sensor is used as an inclination detection device for the vehicle, and the optical axis position of the headlamp is adjusted based on the pitch angle of the vehicle detected by the vehicle height sensor. On the other hand, Patent Document 1 discloses a configuration in which auto-leveling control is performed using a gravity sensor as an inclination detection device. Further, Patent Document 2 discloses a configuration in which auto-leveling control is performed using a three-dimensional gyro sensor as an inclination detection device.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] When an acceleration sensor (gravity sensor), a gyro sensor, a geomagnetic sensor, etc. are used as an inclination detection device for a vehicle, the auto-leveling system can be made less expensive and the weight can be reduced compared to the case where a vehicle height sensor is used. On the other hand, the inventors of the present invention have come to recognize that the conventional auto-leveling control using an acceleration sensor or the like has the following problems.

[0005] That is, for example, the inclination angle detected by the acceleration sensor is the inclination angle of the vehicle with respect to the horizontal plane, which includes the inclination angle of the road surface with respect to the horizontal plane and the inclination angle of the vehicle with respect to the road surface. On the other hand, the inclination angle of the vehicle required for auto-leveling control is the inclination angle of the vehicle with respect to the road surface. In contrast, in the conventional auto-leveling control, when the detection value of the acceleration sensor changes, the optical axis position is adjusted without distinguishing whether the change is a change in the inclination angle of the road surface with respect to the horizontal plane or a change in the inclination angle of the vehicle with respect to the road surface. Therefore, there is room for improvement in enhancing the adjustment accuracy of the optical axis position in the conventional auto-leveling control using an acceleration sensor.

[0006] The present invention has been made based on such recognition by the inventors, and an object thereof is to provide a technique capable of more accurately performing auto-leveling control for acquiring the inclination angle of the vehicle with respect to the horizontal plane from an inclination detection device and adjusting the optical axis position of a vehicle lamp.

Means for Solving the Problems

[0007] In order to solve the above problems, an aspect of the present invention is a control device for a vehicle lamp, the control device including: a receiving unit for receiving the inclination angle of the vehicle with respect to the horizontal plane from an inclination detection device; a control unit configured to generate a control signal for instructing adjustment of the optical axis position of the vehicle lamp in response to a change in the inclination angle while the vehicle is stopped, and to generate a control signal for avoiding generation of the control signal or instructing maintenance of the optical axis position in response to a change in the inclination angle while the vehicle is traveling; and a transmitting unit for transmitting the control signal to an optical axis adjustment unit of the vehicle lamp.

[0008] According to this aspect, it is possible to more accurately perform auto-leveling control for acquiring the inclination angle of the vehicle with respect to the horizontal plane from an inclination detection device and adjusting the optical axis position of a vehicle lamp.

[0009] In the above aspect, when the inclination angle of the vehicle with respect to the horizontal plane is referred to as the total angle, this total angle includes a first angle that is the inclination angle of the road surface with respect to the horizontal plane and a second angle that is the inclination angle of the vehicle with respect to the road surface. When the total angle changes while the vehicle is stopped, the control device may generate a control signal instructing adjustment of the optical axis position by regarding the change in the total angle as a change in the second angle. Also according to this aspect, the auto-leveling control for obtaining the inclination angle of the vehicle with respect to the horizontal plane from the inclination detection device and adjusting the optical axis position of the vehicle lamp can be implemented with higher accuracy.

[0010] In the above aspect, the control unit holds a reference value of the first angle and a reference value of the second angle, holds the first angle obtained from the detection value of the inclination detection device and the reference value of the second angle as a new reference value when the vehicle stops, and when the total angle changes while the vehicle is stopped, generates a control signal instructing adjustment of the optical axis position using the second angle obtained from the detection value of the inclination detection device and the reference value of the first angle, and may hold the obtained second angle as a new reference value. Also according to this aspect, the auto-leveling control for obtaining the inclination angle of the vehicle with respect to the horizontal plane from the inclination detection device and adjusting the optical axis position of the vehicle lamp can be implemented with higher accuracy.

[0011] Further, in the above aspect, the control unit holds a reference value of the first angle and a reference value of the second angle, updates the reference value of the first angle by regarding the change in the total angle during vehicle travel as a change in the first angle, updates the reference value of the second angle by regarding the change in the total angle during vehicle stop as a change in the second angle, and may generate a control signal instructing adjustment of the optical axis position using the updated reference value of the second angle. Also according to this aspect, the auto-leveling control for obtaining the inclination angle of the vehicle with respect to the horizontal plane from the inclination detection device and adjusting the optical axis position of the vehicle lamp can be implemented with higher accuracy.

[0012] In addition, in the above aspect, the tilt detection device is an acceleration sensor capable of detecting the tilt angle of the vehicle as a vector, and the control unit, when the difference between the square of the magnitude of the vehicle acceleration vector obtained from the vehicle speed sensor or the acceleration sensor and the square of the magnitude of the detection value vector of the acceleration sensor is equal to the square of the magnitude of the gravitational acceleration vector after a predetermined time from the start of the vehicle, may correct the reference value of the first angle being held so as to approach 0°. Also, in the above aspect, the tilt detection device is an acceleration sensor capable of detecting the tilt angle of the vehicle as a vector, and the control unit, when the difference between the square of the magnitude of the vehicle acceleration vector obtained from the vehicle speed sensor or the acceleration sensor and the square of the magnitude of the detection value vector of the acceleration sensor is equal to the square of the magnitude of the gravitational acceleration vector before a predetermined time from the stop of the vehicle, may correct the reference value of the first angle obtained at the time of vehicle stop so as to approach 0°. According to these aspects, the accuracy of the auto leveling control can be further improved.

[0013] In addition, in the above aspect, the control unit may generate a control signal for instructing adjustment of the optical axis position using the second angle obtained from the detection value of the tilt detection device and the reference value of the first angle or the detection value of the tilt detection device detected last during the previous drive of the control device at the time of activation of the control device, and hold the obtained second angle as a new reference value. According to this aspect, the accuracy of the auto leveling control can be improved.

[0014] In addition, in the above aspect, the control unit may generate a control signal for instructing adjustment of the optical axis position using the reference value of the second angle being held when the second angle obtained from the detection value of the tilt detection device and the reference value of the first angle exceeds a predetermined range. According to this aspect, the visibility of the driver of the host vehicle can be improved while reducing the risk of dazzling the driver of another vehicle. Also, in the above aspect, the control unit may prohibit generation of a control signal for instructing adjustment of the optical axis position thereafter when the second angle obtained from the detection value of the tilt detection device and the reference value of the first angle exceeds a predetermined range. According to this aspect, glare given to the driver of another vehicle can be surely prevented.

[0015] Another aspect of the present invention is a vehicle lamp, wherein the vehicle lamp is characterized in that the optical axis position is adjusted when the inclination angle of the vehicle with respect to the horizontal plane changes while the vehicle is stopped, and the optical axis position is maintained when the inclination angle of the vehicle with respect to the horizontal plane changes while the vehicle is running.

[0016] Still another aspect of the present invention is a control method for a vehicle lamp, the control method being a control method for a vehicle lamp for adjusting the optical axis of the vehicle lamp based on the inclination angle of the vehicle with respect to the horizontal plane detected by an inclination detection device, characterized in that the optical axis position is adjusted when the inclination angle of the vehicle with respect to the road surface changes, and the optical axis position is maintained when the inclination angle of the road surface with respect to the horizontal plane changes.

[0017] Also by these aspects, the auto-leveling control for obtaining the inclination angle of the vehicle with respect to the horizontal plane from the inclination detection device and adjusting the optical axis position of the vehicle lamp can be implemented with higher accuracy.

Advantages of the Invention

[0018] According to the present invention, the auto-leveling control for obtaining the inclination angle of the vehicle with respect to the horizontal plane from the inclination detection device and adjusting the optical axis position of the vehicle lamp can be implemented with higher accuracy.

Brief Description of the Drawings

[0019]

Figure 1

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Figure 10

Best Mode for Carrying Out the Invention

[0020] Hereinafter, the present invention will be described with reference to the drawings based on preferred embodiments. The same or equivalent components, members, and processes shown in each drawing are denoted by the same reference numerals, and repeated explanations will be omitted as appropriate. Further, the embodiments are illustrative and not restrictive of the invention, and all features and combinations thereof described in the embodiments are not necessarily essential to the invention.

[0021] (Embodiment 1) FIG. 1 is a schematic vertical cross-sectional view for explaining the internal structure of a vehicle lighting system according to Embodiment 1. The vehicle lighting system 200 of the present embodiment is a light distribution variable headlamp system in which a pair of headlamp units formed symmetrically left and right are arranged one by one on the left and right in the vehicle width direction. Since the headlamp units arranged on the left and right have substantially the same configuration except for having a symmetric structure, hereinafter, the structure of the right headlamp unit 210R will be described, and the description of the left headlamp unit will be omitted as appropriate. When describing each member of the left headlamp unit, for convenience of explanation, the same reference numerals as the corresponding members of the headlamp unit 210R are given to each member.

[0022] The headlamp unit 210R includes a lamp body 212 having an opening on the vehicle front side, and a light-transmitting cover 214 that covers the opening. The lamp body 212 has a detachable cover 212a that can be removed when replacing the bulb 14 or the like on the vehicle rear side thereof. A lamp chamber 216 is formed by the lamp body 212 and the light-transmitting cover 214. The lamp chamber 216 houses a lamp unit 10 (vehicle lighting) that irradiates light forward of the vehicle.

[0023] A lamp bracket 218 having a pivot mechanism 218a that serves as a swing center of the lamp unit 10 in the vertical, horizontal, and lateral directions is formed on a part of the lamp unit 10. The lamp bracket 218 is screwed with an aiming adjustment screw 220 rotatably supported on the wall surface of the lamp body 212. Therefore, the lamp unit 10 is fixed at a predetermined position in the lamp chamber 216 determined by the adjustment state of the aiming adjustment screw 220, and can change its posture to a forward tilt posture or a rearward tilt posture or the like around the pivot mechanism 218a with that position as a reference.

[0024] Also, on the lower surface of the lamp unit 10, a rotary shaft 222a of a swivel actuator 222 for configuring an Adaptive Front-lighing System (AFS) or the like, which illuminates the traveling direction during traveling on a curved road, is fixed. The swivel actuator 222 pivots (swivels) the lamp unit 10 in the traveling direction around the pivot mechanism 218a based on data on the steering amount provided from the vehicle side, shape data of the traveling road provided from the navigation system, the relative positional relationship between the host vehicle and a preceding vehicle including oncoming vehicles and preceding vehicles, and the like. As a result, the irradiation area of the lamp unit 10 faces not the front of the vehicle but the tip of the curve of the curved road, improving the driver's forward visibility. The swivel actuator 222 can be configured by, for example, a stepping motor. When the swivel angle is a fixed value, a solenoid or the like can also be used. The swivel actuator 222 is fixed to the unit bracket 224.

[0025] A leveling actuator 226 disposed outside the lamp body 212 is connected to the unit bracket 224. The leveling actuator 226 is configured by, for example, a motor that expands and contracts a rod 226a in the directions of arrows M and N. When the rod 226a extends in the direction of arrow M, the lamp unit 10 swings so as to be in a rearward tilted posture around the pivot mechanism 218a. Conversely, when the rod 226a contracts in the direction of arrow N, the lamp unit 10 swings so as to be in a forward tilted posture around the pivot mechanism 218a. When the lamp unit 10 is in the rearward tilted posture, leveling adjustment can be performed to direct the pitch angle of the optical axis O, that is, the vertical angle of the optical axis O, upward. Also, when the lamp unit 10 is in the forward tilted posture, leveling adjustment can be performed to direct the pitch angle of the optical axis O downward. By performing such leveling adjustment, the optical axis can be adjusted according to the vehicle posture. As a result, the reach distance of the forward irradiation light by the vehicle lamp system 200 can be adjusted to an optimal distance.

[0026] On the inner wall surface of the lamp chamber 216 below the lamp unit 10, an irradiation control unit 228 (control device) that executes control such as turning on / off control of the lamp unit 10, control of forming a light distribution pattern, and adjustment of the optical axis of the lamp unit 10 is arranged. In the case of Fig. 1, an irradiation control unit 228R for controlling the headlamp unit 210R is arranged. This irradiation control unit 228R also executes control of a swivel actuator 222, a leveling actuator 226, etc. Note that the irradiation control unit 228R may be provided outside the headlamp unit 210R.

[0027] The lamp unit 10 can be provided with an aiming adjustment mechanism. For example, an aiming pivot mechanism (not shown) that serves as a swing center during aiming adjustment is arranged at the connection portion between the rod 226a of the leveling actuator 226 and the unit bracket 224. Further, the aforementioned aiming adjustment screws 220 are arranged at intervals in the vehicle width direction on the lamp bracket 218. For example, if the two aiming adjustment screws 220 are rotated counterclockwise, the lamp unit 10 assumes a forward-tilted posture around the aiming pivot mechanism and the optical axis O is adjusted downward. Similarly, if the two aiming adjustment screws 220 are rotated clockwise, the lamp unit 10 assumes a rearward-tilted posture around the aiming pivot mechanism and the optical axis O is adjusted upward. Also, if the aiming adjustment screw 220 on the left side in the vehicle width direction is rotated counterclockwise, the lamp unit 10 assumes a right-rotation posture around the aiming pivot mechanism and the optical axis O is adjusted rightward. Further, if the aiming adjustment screw 220 on the right side in the vehicle width direction is rotated counterclockwise, the lamp unit 10 assumes a left-rotation posture around the aiming pivot mechanism and the optical axis O is adjusted leftward. This aiming adjustment is performed at the time of vehicle shipment, vehicle inspection, or replacement of the headlamp unit 210R. Then, the headlamp unit 210R is adjusted to a posture defined in the design, and based on this posture, control of forming a light distribution pattern and control of adjusting the optical axis position are performed.

[0028] The lamp unit 10 includes a shade mechanism 18 including a rotating shade 12, a bulb 14 as a light source, a lamp housing 17 that supports a reflector 16 on an inner wall thereof, and a projection lens 20. As the bulb 14, for example, an incandescent bulb, a halogen lamp, a discharge bulb, an LED, or the like can be used. In the present embodiment, an example in which the bulb 14 is configured by a halogen lamp is shown. The reflector 16 reflects the light emitted from the bulb 14. Then, a part of the light from the bulb 14 and the light reflected by the reflector 16 is guided through the rotating shade 12 to the projection lens 20.

[0029] The rotating shade 12 is a cylindrical member that can rotate about a rotation axis 12a, and includes a notch portion that is partially cut out in the axial direction and a plurality of shade plates (not shown). Either the notch portion or the shade plate is moved on the optical axis O to form a predetermined light distribution pattern. At least a part of the reflector 16 has an ellipsoidal spherical shape, and this ellipsoidal spherical surface is set so that a cross-sectional shape including the optical axis O of the lamp unit 10 becomes at least a part of an elliptical shape. The ellipsoidal spherical portion of the reflector 16 has a first focus substantially at the center of the bulb 14 and a second focus on the rear focal plane of the projection lens 20.

[0030] The projection lens 20 is disposed on the optical axis O extending in the vehicle longitudinal direction. The bulb 14 is disposed on the rear side of the rear focal plane that is a focal plane including the rear focal point of the projection lens 20. The projection lens 20 is composed of a plano-convex aspherical lens having a convex front surface and a flat rear surface, and projects the light source image formed on the rear focal plane as an inverted image onto a virtual vertical screen in front of the vehicle lamp system 200. Note that the configuration of the lamp unit 10 is not particularly limited thereto, and a reflective lamp unit without the projection lens 20 or the like may be used.

[0031] FIG. 2 is a functional block diagram for explaining the operation cooperation between the irradiation control unit of the headlamp unit configured as described above and the vehicle control unit on the vehicle side. Note that since the configurations of the right headlamp unit 210R and the left headlamp unit 210L are basically the same as described above, only the description of the right headlamp unit 210R side will be given, and the description of the left headlamp unit 210L side will be omitted.

[0032] The irradiation control unit 228R of the headlamp unit 210R includes a receiving unit 228R1, a control unit 228R2, a transmitting unit 228R3, and a memory 228R4. The irradiation control unit 228R controls the power circuit 230 based on the information obtained from the vehicle control unit 302 (vehicle control ECU) mounted on the vehicle 300 and executes the lighting control of the valve 14. Further, the irradiation control unit 228R controls the variable shade control unit 232, the swivel control unit 234, and the leveling control unit 236 (optical axis adjustment unit) based on the information obtained from the vehicle control unit 302. Various information transmitted from the vehicle control unit 302 is received by the receiving unit 228R1, and various control signals are generated by the control unit 228R2 from the information and the information stored in the memory 228R4 as necessary. Then, the control signal is transmitted by the transmitting unit 228R3 to the power circuit 230 of the lamp unit 10, the variable shade control unit 232, the swivel control unit 234, the leveling control unit 236, etc. The memory 228R4 is, for example, a non-volatile memory.

[0033] The variable shade control unit 232 rotationally controls the motor 238 connected to the rotation axis 12a of the rotary shade 12 via a gear mechanism to move a desired shade plate or notch portion onto the optical axis O. Note that the variable shade control unit 232 is provided with rotation information indicating the rotation state of the rotary shade 12 from a detection sensor such as an encoder provided in the motor 238 and the rotary shade 12. Thereby, accurate rotational control by feedback control is realized. Further, the swivel control unit 234 controls the swivel actuator 222 to adjust the angle of the optical axis O of the lamp unit 10 in the vehicle width direction (left and right direction). For example, when turning such as when driving on a curved road or turning right or left, the optical axis O of the lamp unit 10 is directed in the direction of travel.

[0034] The leveling control unit 236 controls the leveling actuator 226 to adjust the optical axis O of the lamp unit 10 in the vehicle's vertical direction (pitch angle direction). For example, in response to the forward or backward tilt of the vehicle's attitude when the load capacity increases or decreases or the number of passengers increases or decreases, the attitude of the lamp unit 10 is adjusted to adjust the reach distance of the forward irradiation light to an optimal distance. The vehicle control unit 302 provides the same information to the headlamp unit 210L, and the irradiation control unit 228L (control device) provided in the headlamp unit 210L executes the same control as the irradiation control unit 228R.

[0035] In the case of this embodiment, the light distribution pattern formed by the headlamp units 210L and 210R can be switched according to the operation content of the light switch 304 by the driver. In this case, in response to the operation of the light switch 304, the irradiation control units 228L and 228R control the motor 238 via the variable shade control unit 232 to determine the light distribution pattern formed by the lamp unit 10.

[0036] The headlamp units 210L and 210R of the present embodiment may be automatically controlled to detect the situation around the vehicle with various sensors regardless of the operation of the light switch 304 and form an optimal light distribution pattern according to the state of the vehicle 300 and the situation around the vehicle. For example, when it is detected that there are a preceding vehicle, an oncoming vehicle, a pedestrian, etc. in front of the host vehicle, the irradiation control units 228L and 228R determine that glare should be prevented based on the information obtained from the vehicle control unit 302, and the lamp unit 10 forms a light distribution pattern for low beam. Also, when it is detected that there are no preceding vehicles, oncoming vehicles, pedestrians, etc. in front of the host vehicle, the irradiation control units 228L and 228R determine that the visibility of the driver should be improved and form a light distribution pattern for high beam without light shielding by the rotary shade 12. Further, in addition to the light distribution patterns for low beam and high beam, if it is possible to form conventionally known special light distribution patterns for special high beam such as so-called left or right partial high beam and light distribution patterns for V beam, and special light distribution patterns for low beam, an optimal light distribution pattern considering the preceding vehicle may be formed according to the presence state of the preceding vehicle. Such a control mode is sometimes referred to as the ADB (Adaptive Driving Beam) mode.

[0037] In order to detect objects such as a preceding vehicle or an oncoming vehicle in this way, a camera 305 such as a stereo camera is connected to the vehicle control unit 302 as an object recognition means. The image frame data captured by the camera 305 is subjected to predetermined image processing such as object recognition processing by the image processing unit 308, and the recognition result is provided to the vehicle control unit 302. For example, when there is data including feature points indicating a vehicle that the vehicle control unit 302 has previously held among the recognition result data provided from the image processing unit 308, the vehicle control unit 302 recognizes the presence of the vehicle and provides the information to the irradiation control units 228L and 228R. The irradiation control units 228L and 228R receive the vehicle information from the vehicle control unit 302, determine an optimal light distribution pattern considering the vehicle, and form the light distribution pattern. Here, the "feature points indicating a vehicle" are, for example, light points with a predetermined luminous intensity or more that appear in the estimated existence region of a marker light such as a headlight or a tail lamp of a preceding vehicle. Also, for example, when there is data including feature points indicating a pedestrian that the vehicle control unit 302 has previously held among the recognition result data provided from the image processing unit 308, the vehicle control unit 302 provides the information to the irradiation control units 228L and 228R, and the irradiation control units 228L and 228R form an optimal light distribution pattern considering the pedestrian.

[0038] In addition, the vehicle control unit 302 can also acquire information from a steering sensor 310, a vehicle speed sensor 312, a navigation system 314, an acceleration sensor 316 as an inclination detection device, etc., mounted on the vehicle 300. Then, based on this, the irradiation control units 228L and 228R can select a light distribution pattern to be formed according to the running state and posture of the vehicle 300, or can simply change the light distribution pattern by changing the direction of the optical axis O. For example, when loading luggage in the luggage compartment at the rear of the vehicle or when there are passengers in the rear seats, the vehicle posture becomes a rearward tilt posture. When the luggage is unloaded or the passengers in the rear seats get off, the vehicle posture tilts forward from the rearward tilt posture state. The irradiation direction of the lamp unit 10 also fluctuates up and down corresponding to the posture state of the vehicle 300, and the forward irradiation distance becomes longer or shorter. Therefore, the irradiation control units 228L and 228R receive the inclination angle of the vehicle 300 from the acceleration sensor 316 via the vehicle control unit 302, and control the leveling actuator 226 via the leveling control unit 236 to make the pitch angle of the optical axis O an angle corresponding to the vehicle posture. In this way, by performing real-time leveling adjustment of the lamp unit 10 based on the vehicle posture, even if the vehicle posture changes according to the usage situation of the vehicle 300, the reach distance of the forward irradiation can be optimally adjusted. Such a control mode is sometimes referred to as an auto-leveling control mode. The automatic formation control of the light distribution pattern including the various control modes described above is executed, for example, when the automatic formation control of the light distribution pattern is instructed by the light switch 304.

[0039] In this embodiment, an acceleration sensor 316 is used as an example of an inclination detection device for detecting the inclination angle of the vehicle 300 with respect to the horizontal plane. However, the inclination detection device is not limited to the acceleration sensor 316, and other sensors such as a gyro sensor or a geomagnetic sensor may be used.

[0040] Subsequently, the auto-leveling control by the vehicle lamp system 200 having the above-described configuration will be described in detail.

[0041] The acceleration sensor 316 of the vehicle lighting system 200 according to this embodiment is, for example, a three-axis acceleration sensor having X-axis, Y-axis, and Z-axis that are orthogonal to each other. The acceleration sensor 316 is attached to the vehicle 300 such that the X-axis of the sensor is along the longitudinal axis of the vehicle 300, the Y-axis of the sensor is along the lateral axis of the vehicle 300, and the Z-axis of the sensor is along the vertical axis of the vehicle 300. The acceleration sensor 316 can detect a combined acceleration vector obtained by combining the gravitational acceleration vector and the motion acceleration vector generated by the movement of the vehicle 300, and outputs numerical values of each component of the combined acceleration vector in the three-axis directions. When the vehicle 300 is in a stationary state, the acceleration sensor 316 outputs numerical values of each component of the gravitational acceleration vector in the three-axis directions. That is, the acceleration sensor 316 can detect, as a vector, the inclination angle of the vehicle with respect to the horizontal plane (total angle) that includes the inclination angle of the road surface with respect to the horizontal plane (first angle) and the inclination angle of the vehicle with respect to the road surface (second angle). In other words, the inclination angle of the vehicle with respect to the horizontal plane can be derived from the detection value of the acceleration sensor 316. Hereinafter, the inclination angle of the road surface with respect to the horizontal plane will be appropriately referred to as the "road surface angle" and denoted by the symbol θr, the inclination angle of the vehicle with respect to the road surface will be referred to as the "vehicle attitude angle" and denoted by the symbol θv, and the inclination angle of the vehicle with respect to the horizontal plane will be referred to as the "total angle" and denoted by the symbol θ. Note that the road surface angle θr, the vehicle attitude angle θv, and the total angle θ are angles in the vertical direction of the X-axis, in other words, angles in the pitch direction of the vehicle 300, respectively.

[0042] Incidentally, the acceleration sensor 316 may be attached to the vehicle 300 in any posture. In this case, the numerical values of the X-axis, Y-axis, and Z-axis components output from the acceleration sensor 316 are converted by the irradiation control unit 228R into the components of the longitudinal axis, lateral axis, and vertical axis of the vehicle, and the total angle θ is derived. Here, when the acceleration sensor 316 is used as the inclination detection device, it is naturally understood that the irradiation control unit 228R receiving the numerical values of the respective axis components of the acceleration vector from the acceleration sensor 316 and deriving the total angle θ from the numerical values of the respective axis components is included in "receiving the total angle from the inclination detection device". In this case, for example, the inclination detection device may be configured by the acceleration sensor 316 and a total angle calculation unit (not shown) included in the irradiation control unit 228R. Further, the detection value of the inclination detection device can be the total angle θ derived from the detection value of the acceleration sensor 316.

[0043] Here, the auto-leveling control is intended to absorb the change in the forward irradiation distance of the vehicle lamp accompanying the change in the inclination angle of the vehicle and maintain the forward reach distance of the irradiation light optimally. Therefore, the inclination angle of the vehicle required for the auto-leveling control is the vehicle attitude angle θv. Thus, the vehicle lamp system 200 according to the present embodiment controls to adjust the optical axis position of the lamp unit 10 when the vehicle attitude angle θv changes and maintain the optical axis position of the lamp unit 10 when the road surface angle θr changes.

[0044] In addition, in this embodiment, the change in the total angle θ during vehicle stop is estimated as the change in the vehicle attitude angle θv, and the change in the total angle θ during vehicle travel is estimated as the change in the road surface angle θr. That is, during travel, since it is rare for the vehicle attitude angle θv to change due to an increase or decrease in the load capacity or the number of passengers, the change in the total angle θ during travel can be estimated as the change in the road surface angle θr. On the other hand, since it is rare for the road surface angle θr to change due to the movement of the vehicle 300 during vehicle stop, the change in the total angle θ during vehicle stop can be estimated as the change in the vehicle attitude angle θv. The irradiation control unit 228R derives the total angle θ from the detection value of the acceleration sensor 316, generates a control signal for instructing adjustment of the optical axis position with respect to the change in the total angle θ during vehicle stop, and avoids generating the control signal with respect to the change in the total angle θ during vehicle travel. Then, the control signal is transmitted to the leveling control unit 236. Note that the irradiation control unit 228R may generate a control signal for instructing maintenance of the optical axis position with respect to the change in the total angle θ during vehicle travel and transmit this control signal to the leveling control unit 236.

[0045] Specifically, first, for example, at a vehicle manufacturer's production factory or a dealer's maintenance factory, the vehicle 300 is placed on a horizontal plane to be in a reference state. In the reference state, the vehicle 300 is in a state where one person is sitting in the driver's seat or in an empty vehicle state. Then, an initialization signal is transmitted to the irradiation control unit 228R through a switch operation of the factory's initialization processing device or communication of a CAN (Controller Area Network) system that connects the irradiation control unit 228R and the acceleration sensor 316 via the vehicle control unit 302. The initialization signal transmitted to the irradiation control unit 228R is received by the receiving unit 228R1 and sent to the control unit 228R2. When receiving the initialization signal, the control unit 228R2 performs initial aiming adjustment using the output value of the acceleration sensor 316 received by the receiving unit 228R1 as the reference inclination angle. In addition, the control unit 228R2 holds these reference values by recording information that the reference value of the road surface angle θr = 0° and the reference value of the vehicle attitude angle θv = 0° in the memory 228R4.

[0046] During vehicle travel, the control unit 228R2 (irradiation control unit 228R) avoids generating a control signal for instructing adjustment of the optical axis position. Whether the vehicle 300 is in motion can be determined, for example, based on the vehicle speed obtained from the vehicle speed sensor 312. The "during vehicle travel" is, for example, from when the detected value of the vehicle speed sensor 312 exceeds 0 until the detected value of the vehicle speed sensor 312 becomes 0. This "during vehicle travel" can be appropriately set based on experiments or simulations by the designer.

[0047] When the vehicle stops, the control unit 228R2 subtracts the reference value of the vehicle attitude angle θv read from the memory 228R4 from the current inclination angle of the vehicle 300, that is, the total angle θ, derived from the detected value of the acceleration sensor 316, to calculate the road surface angle θr at the time of vehicle stop. Then, this road surface angle θr is recorded in the memory 228R4 as a new reference value of the road surface angle θr. The "when the vehicle stops" is, for example, after the detected value of the vehicle speed sensor 312 becomes 0 and when the detected value of the acceleration sensor 316 stabilizes. The reason for setting it when the detected value of the acceleration sensor 316 stabilizes is that it takes some time for the vehicle attitude to stabilize after the vehicle 300 stops, and it is difficult to detect the accurate total angle θ in a state where the vehicle attitude is not stable. This "when it stabilizes" may be when the change amount per unit time of the detected value of the acceleration sensor 316 becomes equal to or less than a predetermined amount, or may be after a predetermined time has elapsed since the detected value of the vehicle speed sensor 312 became 0. The "when the vehicle stops", "predetermined amount", and "predetermined time" can be appropriately set based on experiments or simulations by the designer.

[0048] Note that when the difference between the road surface angle θr at vehicle stop, which is obtained by subtracting the reference value of the vehicle attitude angle θv from the total angle θ at vehicle stop, and the reference value of the road surface angle θr recorded in the memory 228R4 is equal to or greater than a predetermined amount, the calculated road surface angle θr may be recorded in the memory 228R4 as a new reference value. Further, the control unit 228R2 may calculate the road surface angle θr when the total angle θ at the start of the vehicle 300 is different from the total angle θ at stop. According to these, it is possible to avoid frequent rewriting of the reference value of the road surface angle θr, and the control load on the control unit 228R2 can be reduced.

[0049] During vehicle stop, the control unit 228R2 repeatedly calculates the vehicle attitude angle θv at a predetermined timing. The vehicle attitude angle θv is obtained by subtracting the reference value of the road surface angle θr recorded in the memory 228R4 from the current total angle θ. When the difference between the calculated vehicle attitude angle θv and the reference value of the vehicle attitude angle θv is equal to or greater than a predetermined amount, the control unit 228R2 generates a control signal for optical axis adjustment based on the newly obtained vehicle attitude angle θv. Then, the optical axis is adjusted based on this control signal. Further, the calculated vehicle attitude angle θv is recorded in the memory 228R4 as a new reference value. In this way, by performing optical axis adjustment when the difference between the calculated vehicle attitude angle θv and the reference value is equal to or greater than a predetermined amount, frequent optical axis adjustment can be avoided. As a result, the control load on the control unit 228R2 can be reduced, and the service life of the leveling actuator 226 can be extended. The "during vehicle stop" is, for example, from when the detection value of the acceleration sensor 316 becomes stable until the vehicle starts, and this "when the vehicle starts" is, for example, when the detection value of the vehicle speed sensor 312 exceeds 0. Note that the calculation of the vehicle attitude angle θv may be performed not repeatedly at a predetermined timing but at the start of the vehicle. The "during vehicle stop" can be appropriately set based on experiments and simulations by the designer.

[0050] Also, for example, in a configuration where power is not supplied to the irradiation control unit 228R when the ignition (IG) is off, and when the memory 228R4 is not a non-volatile memory, the control unit 228R2 receives an IG-OFF signal transmitted from the vehicle control unit 302 side when the ignition is off, or when the power supply voltage supplied to the irradiation control unit 228R becomes equal to or lower than a predetermined value, records a reference value of the road surface angle θr in a non-volatile memory (not shown). Thereby, since the reference value of the road surface angle θr can be retained even when the ignition is turned off, auto leveling control can be accurately performed even after the ignition is turned on.

[0051] Also, when the ignition is turned on, that is, when the irradiation control unit 228R is activated, the control unit 228R2 calculates the vehicle attitude angle θv from the detected value of the acceleration sensor 316 and the reference value of the road surface angle θr. Then, the control unit 228R2 determines the optical axis position using the calculated vehicle attitude angle θv, and retains it by recording the calculated vehicle attitude angle θv as a new reference value in the memory 228R4. Thereby, even if the vehicle attitude angle θv has changed while the ignition is off, the optical axis O is adjusted to an appropriate position when the ignition is on, so that the accuracy of the auto leveling control can be improved.

[0052] Alternatively, in a configuration where power is not supplied to the irradiation control unit 228R when the ignition is off, if the memory 228R4 is not a non-volatile memory, the control unit 228R2 records, in the non-volatile memory when the ignition is off, a reference value of the vehicle attitude angle θv, and the detection value of the acceleration sensor 316 or the total angle θ detected last before the ignition was turned off, that is, the detection value of the acceleration sensor 316 or the total angle θ detected last during the previous drive (the period from when the ignition was turned on to when the ignition was turned off). Then, when the irradiation control unit 228R is activated, the control unit 228R2 calculates the difference between the total angle θ obtained from the current detection value of the acceleration sensor 316 and the total angle θ obtained from the detection value of the acceleration sensor 316 detected last before the ignition was turned off, and calculates the current vehicle attitude angle θv from the obtained difference and the reference value of the vehicle attitude angle θv. Then, the control unit 228R2 performs optical axis adjustment using the calculated vehicle attitude angle θv, and records the calculated vehicle attitude angle θv in the memory 228R4 as a new reference value. Also in this case, since optical axis adjustment corresponding to the change in the vehicle attitude angle θv during ignition-off is possible, the accuracy of the auto-leveling control can be improved.

[0053] In the above control, the road surface angle θr is calculated by subtracting the reference value of the vehicle attitude angle θv from the total angle θ, and the obtained road surface angle θr is held as a new reference value. However, by holding the total angle θ and the reference value of the vehicle attitude angle θv used in this calculation, it is substantially equivalent to holding the road surface angle θr as a new reference value. Therefore, the holding of the road surface angle θr as a new reference value in this embodiment also includes holding the total angle θ and the reference value of the vehicle attitude angle θv used in the calculation. The same applies to the calculation of the vehicle attitude angle θv. The holding of the vehicle attitude angle θv as a new reference value in this embodiment includes holding the total angle θ and the reference value of the road surface angle θr used in the calculation. In this case, the total angle θ to be held may be the detection value of the acceleration sensor 316 corresponding to this total angle θ.

[0054] FIG. 3 is an auto-leveling control flowchart of the vehicle lamp system according to Embodiment 1. In the flowchart of FIG. 3, the processing procedures of each part are displayed by a combination of S (the initial letter of Step), which means a step, and a number. Further, some determination process is executed in the process displayed by the combination of S and the number. If the determination result is affirmative, Y (the initial letter of Yes) is added and displayed, for example, as (Y of S101). Conversely, if the determination result is negative, N (the initial letter of No) is added and displayed, for example, as (N of S101). This flow is repeatedly executed at a predetermined timing by the irradiation control unit 228R (control unit 228R2) when the ignition is turned on in a state where an execution instruction for the auto-leveling control mode is given by, for example, the light switch 304, and ends when the ignition is turned off.

[0055] First, the control unit 228R2 determines whether the vehicle is running (S101). If the vehicle is running (Y of S101), the control unit 228R2 does not generate a control signal for instructing adjustment of the optical axis position, avoids optical axis adjustment (S102), and ends this routine. If the vehicle is not running (N of S101), the control unit 228R2 determines whether the vehicle is stopped (S103). If the vehicle is stopped (Y of S103), the control unit 228R2 subtracts the reference value of the vehicle attitude angle θv from the current total angle θ to calculate the road surface angle θr (S104), records the calculated road surface angle θr in the memory 228R4 as a new reference value. Then, the irradiation control unit 228R avoids optical axis adjustment (S102) and ends this routine.

[0056] When the vehicle is not stopped (N in S103), in this case, since it means the vehicle is stopped, the control unit 228R2 subtracts the reference value of the road surface angle θr from the current total angle θ to calculate the vehicle attitude angle θv (S106). Subsequently, the control unit 228R2 determines whether the difference between the calculated vehicle attitude angle θv and the reference value of the vehicle attitude angle θv is equal to or greater than a predetermined amount (S107). If the difference is less than the predetermined amount (N in S107), the control unit 228R2 avoids optical axis adjustment (S102) and ends this routine. If the difference is equal to or greater than the predetermined amount (Y in S107), the control unit 228R2 adjusts the optical axis position based on the calculated vehicle attitude angle θv (S108). Then, the control unit 228R2 records the calculated vehicle attitude angle θv as the reference value in the memory 228R4 (S109) and ends this routine.

[0057] Regarding the left headlight unit 210L, the irradiation control unit 228L (control unit 228L2) executes the same control. Alternatively, one of the irradiation control units 228L and 228R may calculate the vehicle attitude angle θv and the road surface angle θr, and the other may obtain the calculated vehicle attitude angle θv and the road surface angle θr to adjust the optical axis O.

[0058] As described above, in the vehicle lighting system 200 according to the present embodiment, when the auto-leveling control is performed based on the total angle θ derived from the detection value of the acceleration sensors 316 by the irradiation control units 228L and 228R, the optical axis position is adjusted when the vehicle attitude angle θv changes, and the optical axis position is maintained when the road surface angle θr changes. Further, in the present embodiment, the change in the total angle θ during vehicle stop is estimated to be the change in the vehicle attitude angle θv, and the change in the total angle θ during vehicle travel is estimated to be the change in the road surface angle θr. Then, the irradiation control units 228L and 228R generate a control signal for instructing adjustment of the optical axis position in response to a change in the total angle θ during vehicle stop, and avoid generating the control signal or generate a control signal for instructing maintenance of the optical axis position in response to a change in the total angle θ during vehicle travel. That is, when the total angle θ changes during vehicle stop, the irradiation control units 228L and 228R generate a control signal for instructing optical axis adjustment by regarding the change in the total angle θ as the change in the vehicle attitude angle θv. Thereby, the auto-leveling control using the tilt detection device for detecting the tilt angle of the vehicle 300 with respect to the horizontal plane can be performed with higher accuracy. Further, in the present embodiment, since the tilt angle of the vehicle 300 is detected using a tilt detection device such as the acceleration sensors 316, there is no need to use a vehicle height sensor. Therefore, it is advantageous in terms of cost reduction compared to the case of using a vehicle height sensor, and the degree of freedom in vehicle body design is high.

[0059] (Embodiment 2) The vehicle lighting system 200 according to Embodiment 2 performs auto-leveling control in consideration of changes in the vehicle attitude angle θv that may occur during vehicle travel. Hereinafter, the present embodiment will be described. Note that since the main configuration of the vehicle lighting system 200, the main flow of the auto-leveling control, the shape of the light distribution pattern that can be formed, etc. are the same as those in Embodiment 1, the same reference numerals are given to the same configurations as those in Embodiment 1, and the description and illustration thereof are omitted as appropriate. FIG. 4 is an explanatory diagram of the auto-leveling control by the vehicle lighting system according to Embodiment 2.

[0060] In Embodiment 1, the change in the vehicle tilt angle (total angle θ) during vehicle travel is estimated as the change in the road surface angle θr. As a result, auto leveling control can be performed with high precision using a simple control structure. However, although rare, the vehicle attitude angle θv may change during vehicle travel. For example, when the vehicle 300 is a large vehicle such as a bus, passengers may move inside the vehicle during vehicle travel, which may change the vehicle attitude angle θv. Therefore, when the change in the total angle θ during vehicle travel is estimated as the change in the road surface angle θr, an error may occur between the actual road surface angle θr and the estimated road surface angle θr.

[0061] Therefore, in the present embodiment, a road surface horizontal determination is performed at least at one of the timings when the vehicle starts and when the vehicle stops. Then, the reference value of the road surface angle θr is corrected according to the result of the road surface horizontal determination.

[0062] The road surface horizontal determination at the time of vehicle start and the reference value correction according to the result are performed as follows. First, the control unit 228R2 determines whether the vehicle 300 has started. The control unit 228R2 can determine that the vehicle 300 has started when the vehicle speed change amount per unit time (the motion acceleration of the vehicle 300) obtained from the detection value of the vehicle speed sensor 312 is equal to or greater than a predetermined value. The predetermined value of the motion acceleration at which it is determined that the vehicle 300 has started can be set as appropriate. Further, the control unit 228R2 determines whether the vehicle 300 is traveling straight. The control unit 228R2 can determine the straight travel of the vehicle from the detection value of the steering sensor 310 or the numerical value of the Y-axis component of the acceleration sensor 316. For example, the control unit 228R2 determines that the vehicle 300 is traveling straight when the steering angle is near 0° from the detection value of the steering sensor 310. The range of the steering angle at which it is determined that the vehicle 300 is traveling straight can be set as appropriate.

[0063] When the vehicle 300 is moving straight, the control unit 228R2 calculates the square of the magnitude of the vehicle 300's motion acceleration vector obtained from the vehicle speed sensor 312 or the acceleration sensor 316, and the square of the magnitude of the detected value vector of the acceleration sensor 316, after a predetermined time from the start of the vehicle. Then, when the difference is equal to the square of the magnitude of the gravitational acceleration vector, the control unit 228R2 corrects the reference value of the road surface angle θr it holds to approach 0°.

[0064] Also, the road surface horizontal determination at the time of vehicle stop and the reference value correction according to the result are carried out as follows. First, the control unit 228R2 determines whether vehicle stop is predicted. The control unit 228R2 can predict that the vehicle 300 will stop when the amount of change in vehicle speed per unit time (the vehicle 300's motion deceleration, that is, negative motion acceleration) obtained from the detected value of the vehicle speed sensor 312 is equal to or greater than a predetermined value. The predetermined value of the motion deceleration at which vehicle stop of the vehicle 300 is predicted can be set as appropriate. Also, the control unit 228R2 determines whether the vehicle 300 is moving straight.

[0065] When the vehicle 300 is moving straight and then the vehicle speed becomes 0 and the vehicle 300 stops, the control unit 228R2 calculates the square of the magnitude of the vehicle 300's motion acceleration vector obtained from the vehicle speed sensor 312 or the acceleration sensor 316, and the square of the magnitude of the detected value vector of the acceleration sensor 316, a predetermined time before vehicle stop. Then, when the difference is equal to the square of the magnitude of the gravitational acceleration vector, the control unit 228R2 corrects the reference value of the road surface angle θr obtained at the time of vehicle stop to approach 0°.

[0066] As shown in FIG. 4, for example, when a vehicle 300 with a pitch angle tilted by the vehicle attitude angle θv stops on a road with a road surface angle θr, a gravitational acceleration of magnitude G and a motion acceleration (motion deceleration) of magnitude α in the direction in which the vehicle 300 decelerates act on the vehicle 300. This motion acceleration is a vector parallel to the road surface. Therefore, the X-axis component, Y-axis component, and Z-axis component of the detected value vector V = (x, y, z) of the acceleration sensor 316 in this state can be expressed by the following equations (1) to (3).

[0067] [Number]

[0068] Then, the square of the magnitude of the detection value vector V of this acceleration sensor 316 is represented by the following formula (4).

[0069] [Number]

[0070] Here, by transforming the above formula (4), the following formula (5) can be obtained.

[0071] [Number]

[0072] When the vehicle 300 stops on a horizontal road, that is, when the road surface angle θr = 0°, it can be seen from the above formula (5) that the difference between the square of the magnitude of the detection value vector V of the acceleration sensor 316 and the square of the magnitude α of the motion acceleration vector is equal to the square of the magnitude G of the gravitational acceleration vector. Therefore, by calculating the square of the magnitude α of the motion acceleration vector of the vehicle 300 obtained from the vehicle speed sensor 312 or the acceleration sensor 316 and the square of the magnitude of the detection value vector V of the acceleration sensor 316, and determining whether the difference is equal to the square of the magnitude G of the gravitational acceleration vector, it is possible to determine whether the vehicle 300 is on a horizontal plane. Therefore, when the difference between the square of the magnitude of the motion acceleration vector and the square of the magnitude of the detection value vector at a predetermined time before the vehicle stops is equal to the square of the magnitude of the gravitational acceleration vector, the control unit 228R2 performs correction to make the reference value of the road surface angle θr obtained when the vehicle stops approach 0°. The correction amount can be in the range of, for example, 0.01° to 0.1°.

[0073] Also, regarding when the vehicle starts, the detected value vector, the motion acceleration vector, and the gravitational acceleration vector of the acceleration sensor 316 have the same relationship as when the vehicle stops. Therefore, when the difference between the square of the magnitude of the motion acceleration vector and the square of the magnitude of the detected value vector after a predetermined time from the start of the vehicle is equal to the square of the magnitude of the gravitational acceleration vector, the control unit 228R2 performs correction to make the reference value of the road surface angle θr it holds approach 0°. By performing the above-described correction either when the vehicle starts or when the vehicle stops, it is possible to improve the accuracy of the auto-leveling control while suppressing an increase in the control burden on the control unit 228R2. Also, when it is performed both at start and stop, the accuracy of the auto-leveling control can be further improved.

[0074] The “predetermined time after the start of the vehicle” and the “predetermined time before the stop of the vehicle” are times at which the above-described horizontal determination can be performed on a road surface that is substantially equal in road surface angle θr to the road surface at the point where the reference value of the road surface angle θr to be corrected is calculated. That is, in the case of vehicle start, by performing the horizontal determination on the road surface immediately after the start, it is possible to substantially determine the horizontality of the road surface at the point where the reference value of the road surface angle θr to be corrected is calculated. Also, in the case of vehicle stop, by performing the horizontal determination on the road surface immediately before the stop, it is possible to substantially determine the horizontality of the road surface at the point where the reference value of the road surface angle θr to be corrected is calculated. And as a result of the determination, if the reference value of the road surface angle θr is not 0° even though the road surface is horizontal, it means that there is an error between the actual road surface angle θr and the recorded reference value of the road surface angle θr, and thus the reference value is corrected to approach 0°.

[0075] Accordingly, even when the vehicle attitude angle θv changes during vehicle travel, a reference value of the road surface angle θr that takes this change into account can be obtained. And since the vehicle attitude angle θv is calculated using the corrected reference value of the road surface angle θr, the vehicle attitude angle θv can be calculated more accurately. The “predetermined time after vehicle start” and “predetermined time before vehicle stop” can be appropriately set based on experiments and simulations by the designer. Also, for the horizontal determination of the road surface, when the difference between the square of the magnitude of the motion acceleration vector and the square of the magnitude of the detection value vector is equal to the square of the magnitude of the gravitational acceleration vector for a predetermined time, for example, 3 seconds or more continuously, it may be determined that the road surface is horizontal.

[0076] FIG. 5 is a control flowchart of road surface horizontal determination and road surface angle correction at the time of vehicle start in the vehicle lighting system according to Embodiment 2. This flow is repeatedly executed at a predetermined timing by the control unit 228R2 (irradiation control unit 228R) when the ignition is turned on in a state where an execution instruction for the auto leveling control mode is given by, for example, the light switch 304, and ends when the ignition is turned off. Also, this flow is appropriately incorporated into the control flow of Embodiment 1.

[0077] First, the control unit 228R2 determines whether the vehicle is stopped (S201). If the vehicle is not stopped (N in S201), the control unit 228R2 ends this routine. If the vehicle is stopped (Y in S201), the control unit 228R2 determines whether the motion acceleration of the vehicle 300 is equal to or greater than a predetermined value (S202). That is, the control unit 228R2 determines whether the vehicle 300 has started. If the motion acceleration is less than the predetermined value (N in S202), the control unit 228R2 repeatedly determines whether the motion acceleration of the vehicle 300 is equal to or greater than the predetermined value (S202). If the motion acceleration is equal to or greater than the predetermined value (Y in S202), the control unit 228R2 determines whether the steering wheel angle is near 0° (S203).

[0078] When the steering angle is not near 0° (N in S203), the control unit 228R2 ends this routine. When the steering angle is near 0° (Y in S203), the control unit 228R2 performs road surface horizontal determination (S204). Then, the control unit 228R2 determines whether the road surface is horizontal (S205). When the road surface is not horizontal (N in S205), the control unit 228R2 ends this routine. When the road surface is horizontal (Y in S205), the control unit 228R2 corrects the reference value of the road surface angle θr so as to approach 0° (S206), and ends this routine.

[0079] FIG. 6 is a control flowchart of road surface horizontal determination and road surface angle correction when the vehicle stops in the vehicle lamp system according to Embodiment 2. This flow is repeatedly executed at a predetermined timing by the control unit 228R2 (irradiation control unit 228R) when the ignition is turned on in a state where an execution instruction for the auto leveling control mode is given by, for example, the light switch 304, and ends when the ignition is turned off. Also, this flow is appropriately incorporated into the control flow of Embodiment 1.

[0080] First, the control unit 228R2 determines whether the vehicle is in motion (S301). When the vehicle is not in motion (N in S301), the control unit 228R2 ends this routine. When the vehicle is in motion (Y in S301), the control unit 228R2 determines whether the motion deceleration of the vehicle 300 is equal to or greater than a predetermined value (S302). When the motion deceleration is less than the predetermined value (N in S302), the control unit 228R2 ends this routine. When the motion deceleration is equal to or greater than the predetermined value (Y in S302), the control unit 228R2 determines whether the steering angle is near 0° (S303).

[0081] When the steering angle is not near 0° (N in S303), the control unit 228R2 ends this routine. When the steering angle is near 0° (Y in S303), the control unit 228R2 determines whether the vehicle speed is 0 based on the detected value of the vehicle speed sensor 312 (S304). When the vehicle speed is not 0 (N in S304), the control unit 228R2 ends this routine. When the vehicle speed is 0 (Y in S304), the control unit 228R2 performs a road surface level determination (S305) and determines whether the road surface is level (S306). When the road surface is not level (N in S306), the control unit 228R2 ends this routine. When the road surface is level (Y in S306), the control unit 228R2 corrects the reference value of the road surface angle θr to approach 0° (S307) and ends this routine.

[0082] As described above, in the vehicle lighting system 200 according to this embodiment, the irradiation control units 228L and 228R perform a road surface level determination at least at one of the timings when the vehicle starts and when the vehicle stops, and correct the reference value of the road surface angle θr according to the result. Therefore, even when the vehicle attitude angle θv changes during vehicle travel, a reference value of the road surface angle θr that takes into account the change can be obtained, so that the accuracy of the auto leveling control can be further improved.

[0083] (Embodiment 3) The vehicle lighting system 200 according to Embodiment 3 takes into account a change in the road surface angle θr that may occur while the vehicle is stopped in the auto leveling control. Hereinafter, this embodiment will be described. Note that since the main configuration of the vehicle lighting system 200, the main flow of the auto leveling control, the shape of the light distribution pattern that can be formed, etc. are the same as those in Embodiment 1, the same components as those in Embodiment 1 are denoted by the same reference numerals, and the description and illustration thereof are omitted as appropriate.

[0084] In Embodiment 1, the change in the vehicle tilt angle (total angle θ) while the vehicle is stopped is estimated as the change in the vehicle attitude angle θv. As a result, auto-leveling control can be performed with high precision using a simple control structure. However, although rare, the road surface angle θr may change while the vehicle is stopped. For example, when the vehicle 300 is transported or towed by a ship, a carrier car, etc., the road surface angle θr can change while the vehicle is stopped. Therefore, when the change in the total angle θ during vehicle travel is estimated as the change in the vehicle attitude angle θv, there is a possibility of an error occurring between the actual vehicle attitude angle θv and the estimated vehicle attitude angle θv.

[0085] Therefore, in this embodiment, it is determined whether the vehicle attitude angle θv obtained from the total angle θ and the reference value of the road surface angle θr is included in a predetermined range, and auto-leveling control is performed or the auto-leveling control is stopped according to the determination result.

[0086] When the vehicle attitude angle θv obtained from the total angle θ derived from the detection value of the acceleration sensor 316 and the reference value of the road surface angle θr exceeds a predetermined range, the control unit 228R2 determines the optical axis position of the lamp unit 10 using the reference value of the vehicle attitude angle θv that it holds. When the calculated vehicle attitude angle θv is included in the predetermined range, the control unit 228R2 determines the optical axis position using the calculated vehicle attitude angle θv. Thereby, it is possible to improve the visibility of the driver of the host vehicle while reducing the possibility of dazzling the driver of another vehicle. The “predetermined range” is, for example, the range from the vehicle attitude angle θv in the empty vehicle state to the vehicle attitude angle θv in the state where the maximum load is applied to the cargo compartment, that is, the range of the vehicle attitude angle θv that the vehicle 300 can substantially take, with a margin of 0.1° added. When the calculated vehicle attitude angle θv exceeds this range, it can be estimated that the calculated vehicle attitude angle θv is different from the actual vehicle attitude angle θv.

[0087] In addition, when the calculated vehicle attitude angle θv exceeds a predetermined range, the control unit 228R2 may prohibit the generation of a control signal for instructing the subsequent adjustment of the optical axis position. Specifically, when the calculated vehicle attitude angle θv exceeds a predetermined range, the control unit 228R2 stops the generation of the control signal (stops the auto-leveling control). Then, the control unit 228R2 lights an indicator (not shown) via the vehicle control unit 302 to notify the user of the abnormality of the auto-leveling control. Further, the control unit 228R2 generates auto-leveling control stop information and records it in the memory 228R4. Thereafter, even if an execution instruction for the auto-leveling control is given by an operation of the light switch 304 or the like, when the auto-leveling control stop information is read from the memory 228R4, the control unit 228R2 avoids executing the auto-leveling control and lights the indicator. When the control unit 228R2 receives a reset signal transmitted to the irradiation control unit 228R by a switch operation at a dealer's maintenance factory or communication of the CAN system, etc., it resets the reference value of the vehicle attitude angle θv and the reference value of the road surface angle θr to 0°. Further, the control unit 228R2 erases or invalidates the auto-leveling control stop information and restores the auto-leveling control to an executable state. Thereby, it is possible to more surely prevent dazzling other vehicle drivers.

[0088] Also, for example, in a configuration where power is not supplied to the irradiation control unit 228R when the ignition is off and the memory 228R4 is not a non-volatile memory, the control unit 228R2 receives an IG-OFF signal issued from the vehicle control unit 302 side when the ignition is turned off, or when the power supply voltage supplied to the irradiation control unit 228R becomes equal to or lower than a predetermined value, records the reference value of the vehicle attitude angle θv in addition to the reference value of the road surface angle θr in a non-volatile memory (not shown). Thereby, the reference value of the vehicle attitude angle θv can be held even when the ignition is turned off.

[0089] Transportation and towing of the vehicle 300 by the above-mentioned ships, carrier cars, etc. are often performed with the ignition turned off. Therefore, the control unit 228R2 may determine whether the vehicle attitude angle θv calculated when the ignition is turned on is within a predetermined range, and execute the above control based on the determination result.

[0090] FIG. 7 is a flowchart of the determination control of the vehicle attitude angle θv in the vehicle lamp system according to Embodiment 3. This flow is repeatedly executed at a predetermined timing by the control unit 228R2 (irradiation control unit 228R) when the ignition is turned on in a state where an execution instruction for the auto leveling control mode is given by, for example, the light switch 304, and ends when the ignition is turned off. Also, this flow is appropriately incorporated into the control flow of Embodiment 1.

[0091] First, the control unit 228R2 calculates the vehicle attitude angle θv from the total angle θ and the reference value of the road surface angle θr (S401), and determines whether the calculated vehicle attitude angle θv is outside the predetermined range (S402). If the calculated vehicle attitude angle θv is outside the predetermined range (Y in S402), the control unit 228R2 performs optical axis adjustment using the reference value of the recorded vehicle attitude angle θv (S403), and ends this routine. If the calculated vehicle attitude angle θv is within the predetermined range (N in S402), the control unit 228R2 performs optical axis adjustment using the calculated vehicle attitude angle θv (S404), and ends this routine.

[0092] FIG. 8 is another flowchart of the determination control of the vehicle attitude angle θv in the vehicle lamp system according to Embodiment 3. This flow is repeatedly executed at a predetermined timing by the control unit 228R2 (irradiation control unit 228R) when the ignition is turned on in a state where an execution instruction for the auto leveling control mode is given by, for example, the light switch 304, and ends when the ignition is turned off. Also, this flow is appropriately incorporated into the control flow of Embodiment 1.

[0093] First, the control unit 228R2 determines whether the auto-leveling control stop information is recorded in the memory 228R4 (S501). If there is auto-leveling control stop information (Y in S501), the control unit 228R2 stops the auto-leveling control and turns on the indicator (S502). Subsequently, the control unit 228R2 determines whether a reset signal is detected (S503). If a reset signal is detected (Y in S503), the control unit 228R2 resets the reference values of the vehicle attitude angle θv and the road surface angle θr to 0°, deletes the auto-leveling control stop information, turns off the indicator (S504), and ends this routine. If a reset signal is not detected (N in S503), this routine ends.

[0094] If there is no auto-leveling control stop information (N in S501), the control unit 228R2 calculates the vehicle attitude angle θv from the total angle θ and the reference value of the road surface angle θr (S505), and determines whether the calculated vehicle attitude angle θv is outside a predetermined range (S506). If the calculated vehicle attitude angle θv is outside the predetermined range (Y in S506), the control unit 228R2 generates the auto-leveling control stop information and records it in the memory 228R4 (S507). Then, the control unit 228R2 stops the auto-leveling control and turns on the indicator (S502). Subsequently, the control unit 228R2 performs the detection determination of the reset signal (S503), the reset of the reference values of the vehicle attitude angle θv and the road surface angle θr, the deletion of the auto-leveling control stop information, and the control of turning off the indicator (S504) to end this routine.

[0095] If the calculated vehicle attitude angle θv is within the predetermined range (N in S506), the control unit 228R2 performs optical axis adjustment using the calculated vehicle attitude angle θv (S508), and ends this routine.

[0096] As described above, in the vehicle lighting system 200 according to the present embodiment, the irradiation control units 228L and 228R determine whether the calculated vehicle attitude angle θv is included in a predetermined range. Then, when the calculated vehicle attitude angle θv deviates from the predetermined range, the irradiation control units 228L and 228R perform auto leveling control using the reference value of the held vehicle attitude angle θv. Therefore, even when the road surface angle θr changes while the vehicle is stopped, auto leveling control considering the change can be performed, so that the visibility of the driver of the host vehicle can be improved while reducing the glare given to the drivers of other vehicles. Alternatively, when the calculated vehicle attitude angle θv deviates from the predetermined range, the irradiation control units 228L and 228R stop the auto leveling control. Thereby, glare given to the drivers of other vehicles can be surely prevented.

[0097] (Embodiment 4) The vehicle lighting system 200 according to Embodiment 4 differs from Embodiment 1 in the method of auto leveling control. Hereinafter, this embodiment will be described. Since the configuration of the vehicle lighting system 200 is the same as that of Embodiment 1, the same reference numerals are given to the same configurations as those in Embodiment 1, and the description and illustration thereof are omitted as appropriate. Also, as in each of the above-described embodiments, in this embodiment as well, only the description of the right headlight unit 210R side will be given, and the description of the left headlight unit 210L side will be omitted as appropriate.

[0098] In the auto leveling control of this embodiment, first, the vehicle 300 is placed in the above-described reference state. Then, an initialization signal is transmitted to the irradiation control unit 228R by a switch operation or the like of the initialization processing device. When receiving the initialization signal, the control unit 228R2 starts initial aiming adjustment and aligns the optical axis O of the lamp unit 10 with the initial setting position. Further, the control unit 228R2 records the output value of the acceleration sensor 110 when the vehicle 300 is in the reference state in the memory 228R4 as the reference value of the road surface angle θr (θr = 0°) and the reference value of the vehicle attitude angle θv (θv = 0°).

[0099] In the situation where the vehicle 300 is actually used, the control unit 228R2 avoids adjusting the optical axis with respect to the change in the total angle θ during vehicle travel. The control unit 228R2 may avoid adjusting the optical axis by avoiding the output of a control signal for instructing the optical axis adjustment, or may generate a maintenance signal for instructing the maintenance of the optical axis position and avoid adjusting the optical axis by outputting this maintenance signal. When avoiding the output of the control signal, the output of the control signal may be avoided by not generating the control signal, or the output of the generated control signal may be avoided after generating the control signal.

[0100] Further, the control unit 228R2 updates the reference value of the road surface angle θr by regarding the change in the total angle θ during vehicle travel as the change in the road surface angle θr. For example, the control unit 228R2 calculates the difference Δθ1 in the total angle θ before and after travel when the vehicle stops. Then, the control unit 228R2 calculates a new reference value of the road surface angle θr by adding the obtained difference Δθ1 to the reference value of the road surface angle θr recorded in the memory 228R4 (new θr reference value = θr reference value + Δθ1), and records this in the memory 228R4.

[0101] The control unit 228R2 calculates the difference Δθ1 as follows, for example. That is, the control unit 228R2 records the total angle θ immediately before starting as the reference value of the total angle θ in the memory 228R4 immediately after the vehicle 300 starts. Then, when the vehicle stops, the control unit 228R2 calculates the difference Δθ1 by subtracting the reference value of the total angle θ from the current (when the vehicle stops) total angle θ. Note that the control unit 228R2 periodically receives acceleration from the acceleration sensor 316 and holds the acceleration for a predetermined period or the total angle θ obtained from the acceleration. The "immediately after starting" is, for example, a predetermined period from when the detection value of the vehicle speed sensor 312 exceeds 0. The "immediately before starting" is, for example, the time a predetermined time before from when the detection value of the vehicle speed sensor 312 exceeds 0. The "immediately after starting" and "immediately before starting" can be appropriately set based on experiments and simulations by the designer.

[0102] While the vehicle is stopped, the control unit 228R2 updates the reference value of the vehicle attitude angle θv by taking the change in the total angle θ during vehicle stop as the change in the vehicle attitude angle θv, and generates a control signal for instructing adjustment of the optical axis position using the updated reference value of the vehicle attitude angle θv. For example, the control unit 228R2 calculates the difference Δθ2 between the current total angle θ and the reference value of the total angle θ recorded in the memory 228R4 while the vehicle is stopped. The reference value of the total angle θ used at this time is, for example, the reference value updated after the calculation of the difference Δθ1 in the first calculation of the difference Δθ2 after the stop of the vehicle 300, that is, the total angle θ at the time of vehicle stop, and in the case of the second and subsequent times, it is the reference value updated after the calculation of the previous difference Δθ2. Then, the control unit 228R2 calculates a new reference value of the vehicle attitude angle θv by adding the obtained difference Δθ2 to the reference value of the vehicle attitude angle θv recorded in the memory 228R4 (new θv reference value = θv reference value + Δθ2), and records this in the memory 228R4.

[0103] Note that the control unit 228R2 may perform optical axis adjustment so as to displace the optical axis O by only the difference Δθ2 corresponding to the change amount of the total angle θ during vehicle stop without holding the reference value of the road surface angle θr and the reference value of the vehicle attitude angle θv in the memory 228R4.

[0104] FIG. 9 is an auto - leveling control flowchart of the vehicle lamp system according to Embodiment 4. First, the control unit 228R2 determines whether the vehicle is in motion (S601). If the vehicle is in motion (Y in S601), the control unit 228R2 determines whether the vehicle 300 has just started (S602). If it has just started (Y in S602), the control unit 228R2 records (updates) the total angle θ immediately before starting as the reference value of the total angle θ in the memory 228R4 (S603), avoids optical axis adjustment (S604), and ends this routine. If it has not just started (N in S602), the control unit 228R2 avoids optical axis adjustment (S604) without updating the reference value of the total angle θ, and ends this routine.

[0105] When the vehicle is not in motion (N in S601), the control unit 228R2 determines whether the vehicle is stopped (S605). If the vehicle is stopped (Y in S605), the control unit 228R2 subtracts the reference value of the total angle θ from the current total angle θ to calculate the difference Δθ1 (S606). Then, the control unit 228R2 calculates a new reference value of the road surface angle θr from the calculated difference Δθ1 and the reference value of the road surface angle θr recorded in the memory 228R4, and updates the reference value of the road surface angle θr (S607). Further, the control unit 228R2 records the current total angle θ as the new reference value of the total angle θ in the memory 228R4 (S608), and ends this routine.

[0106] If the vehicle is not stopped (N in S605), in this case, since it means the vehicle is in motion, the control unit 228R2 subtracts the reference value of the total angle θ from the current total angle θ to calculate the difference Δθ2 (S609). The control unit 228R2 calculates a new reference value of the vehicle attitude angle θv from the calculated difference Δθ2 and the reference value of the vehicle attitude angle θv recorded in the memory 228R4, and updates the reference value of the vehicle attitude angle θv (S610). Then, the control unit 228R2 performs optical axis adjustment according to the updated reference value of the vehicle attitude angle θv (S611). Further, the control unit 228R2 records the current total angle θ as the new reference value of the total angle θ in the memory 228R4 (S612), and ends this routine.

[0107] Regarding the left headlight unit 210L, the irradiation control unit 228L may execute the same control, or one of the irradiation control units 228L and 228R may calculate the vehicle attitude angle θv and the road surface angle θr, and the other may obtain the calculated vehicle attitude angle θv and road surface angle θr and adjust the optical axis O.

[0108] As described above, even with the auto-leveling control of the present embodiment, the auto-leveling control can be implemented with higher precision. Further, in the auto-leveling control of the present embodiment, a difference Δθ1, which is a change in the total angle θ during vehicle travel, is added to a reference value of the road surface angle θr to derive a new road surface angle θr, and a difference Δθ2, which is a change in the total angle θ during vehicle stop, is added to a reference value of the vehicle attitude angle θv to derive a new vehicle attitude angle θv. Therefore, it is possible to avoid the accumulation of errors in the reference value of the road surface angle θr and the reference value of the vehicle attitude angle θv that may occur in the auto-leveling control of Embodiment 1.

[0109] Note that the vehicle lamp system 200 according to each embodiment is one aspect of the present invention. This vehicle lamp system 200 includes a lamp unit 10 whose optical axis O can be adjusted, an acceleration sensor 316 (tilt detection unit) capable of detecting the tilt angle of the vehicle 300 with respect to the horizontal plane, and irradiation control units 228L and 228R for controlling the lamp unit 10, and the irradiation control units 228L and 228R execute the above-described auto-leveling control.

[0110] As another aspect of the present invention, the irradiation control units 228L and 228R as control devices can be cited. The irradiation control units 228L and 228R include a receiving unit 228L1 and 228R1 for receiving the tilt angle of the vehicle 300 with respect to the horizontal plane from the tilt detection device, a control unit 228L2 and 228R2 for executing the above-described auto-leveling control, and a transmitting unit 228L3 and 228R3 for transmitting a control signal generated by the control unit 228L2 and 228R2 to the leveling control unit 236. The irradiation control unit 228 in the vehicle lamp system 200 corresponds to a control unit in a broad sense, and the control units 228L2 and 228R2 in the irradiation control unit 228 correspond to a control unit in a narrow sense.

[0111] Furthermore, as another aspect of the present invention, the lamp unit 10 as a vehicle lamp can be cited. The optical axis position of the lamp unit 10 is adjusted when the tilt angle of the vehicle 300 with respect to the horizontal plane changes during vehicle stop, and the optical axis position is maintained when the tilt angle of the vehicle 300 with respect to the horizontal plane changes during vehicle travel.

[0112] Furthermore, as another aspect of the present invention, a method for controlling a vehicle lamp can be cited. When adjusting the optical axis O of the lamp unit 10 based on the inclination angle of the vehicle 300 with respect to the horizontal plane detected by the inclination detection device, this control method adjusts the optical axis position when the inclination angle of the vehicle 300 with respect to the road surface changes, and maintains the optical axis position when the inclination angle of the road surface with respect to the horizontal plane changes.

[0113] The present invention is not limited to the above-described embodiments, and it is also possible to combine the embodiments or make various design changes and other modifications based on the knowledge of those skilled in the art. Embodiments combined or modified in such a manner are also included in the scope of the present invention. New embodiments resulting from combinations of the above-described embodiments with each other and combinations of the above-described embodiments with the following modification examples have the effects of the combined embodiments and modification examples.

[0114] In the above-described embodiments, the determination of the traveling state of the host vehicle (including whether the vehicle is going straight or not, the calculation of the motion acceleration of the vehicle 300, etc.), the determination of the optical axis position, and the determination of the light distribution pattern may be performed by either the vehicle control unit 302 or the irradiation control unit 228. When the irradiation control unit 228 performs these determinations, information from various sensors and the navigation system is transmitted to the irradiation control unit 228 via the vehicle control unit 302. Also, when the irradiation control unit 228 performs these determinations, one or both of the irradiation control unit 228L and the irradiation control unit 228R can perform these determinations. Further, the irradiation control unit 228 may control the leveling actuator 226 as an optical axis adjustment unit without passing through the leveling control unit 236. That is, the irradiation control unit 228 may function as the leveling control unit 236. When the vehicle control unit 302 performs these determinations, the irradiation control unit 228 controls the lighting and extinguishing of the bulb 14, the driving of the swivel actuator 222, the leveling actuator 226, and the motor 238 based on an instruction from the vehicle control unit 302. In this case, the vehicle control unit 302 constitutes a control device that executes auto-leveling control.

[0115] In addition, the following modified examples can be cited for the functional configuration of the vehicle lighting system. FIG. 10 is a functional block diagram for explaining the operation cooperation of the headlamp unit, the vehicle control unit, and the leveling ECU in the vehicle lighting system according to the modified example. Note that since the configurations of the right headlamp unit 210R and the left headlamp unit 210L are basically the same as described above, in FIG. 10, the headlamp unit 210R and the headlamp unit 210L are collectively referred to as the headlamp unit 210.

[0116] The leveling ECU 100 (control device for vehicle lighting) includes a receiving unit 102, a control unit 104, a transmitting unit 106, a memory 108, an acceleration sensor 110, and a temperature sensor 112. The leveling ECU 100 is installed, for example, near the dashboard of the vehicle 300. Note that the installation position of the leveling ECU 100 is not particularly limited, and it may be provided, for example, inside the headlamp unit 210. Also, the installation position of the acceleration sensor 110 is not particularly limited, and it may be provided, for example, outside the leveling ECU 100. For example, the acceleration sensor 110 can be provided at an arbitrary position inside the vehicle body or inside the headlamp unit 210. Also, an acceleration sensor mounted on an ECU of another system provided in the vehicle 300, such as an airbag system, may be diverted. Furthermore, a plurality of acceleration sensors, such as a combination of the acceleration sensor 110 for the auto-leveling system and the acceleration sensors of other systems, may be used. The installation position of the leveling ECU 100 and the installation position of the acceleration sensor 110 can be arbitrarily combined.

[0117] Also, in this modified example, an acceleration sensor 110 is used as an example of the inclination detection device, but the inclination detection device is not limited to the acceleration sensor 110, and for example, other sensors such as a gyro sensor or a geomagnetic sensor may be used.

[0118] The leveling ECU 100 is connected to the vehicle control unit 302 and the light switch 304 mounted on the vehicle 300. The signals output from the vehicle control unit 302 and the light switch 304 are received by the receiving unit 102. The receiving unit 102 also receives the output values of the acceleration sensor 110 and the temperature sensor 112. The vehicle control unit 302 is connected to a steering sensor 310, a vehicle speed sensor 312, a navigation system 314, etc., and can obtain various information from these sensors and transmit it to the leveling ECU 100 or the like. For example, the vehicle control unit 302 transmits the output value of the vehicle speed sensor 312 to the leveling ECU 100. Thereby, the leveling ECU 100 can detect the running state of the vehicle 300.

[0119] The light switch 304 transmits signals such as a signal instructing the lighting and extinguishing of the headlight unit 210, a signal instructing the light distribution pattern to be formed by the headlight unit 210, and a signal instructing the execution of auto leveling control, according to the operation content of the driver, to the power supply 306, the vehicle control unit 302, the leveling ECU 100, etc. For example, the light switch 304 transmits a signal instructing the execution of auto leveling control to the leveling ECU 100. Thereby, the leveling ECU 100 starts the auto leveling control of the above-described embodiments.

[0120] The signals received by the receiving unit 102 are transmitted to the control unit 104. The control unit 104 derives the change in the inclination angle of the vehicle 300 based on the output value of the acceleration sensor 110 sent from the receiving unit 102 and the information held in the memory 108 as necessary, and generates a control signal instructing the adjustment of the optical axis of the lamp unit 10. The control unit 104 outputs the generated control signal from the transmitting unit 106 to the leveling actuator 226.

[0121] The vehicle 300 is equipped with a power supply 306 that supplies power to the leveling ECU 100, the vehicle control ECU 302, and the headlight unit 210. When the lighting of the headlight unit 210 is instructed by the operation of the light switch 304, power is supplied from the power supply 306 to the bulb 14 via the power supply circuit 230.

[0122] Note that when comparing the configuration of this modified example (see Fig. 10) with the configuration of the first embodiment (see Fig. 2), the leveling ECU 100 of this modified example corresponds to the irradiation control unit 228 (228R, 228L) of the first embodiment. Also, the receiving unit 102 corresponds to the receiving units 228L1, 228R1, the control unit 104 corresponds to the control units 228L2, 228R2, the transmitting unit 106 corresponds to the transmitting units 228L3, 228R3, the memory 108 corresponds to the memories 228L4, 228R4, and the acceleration sensor 110 corresponds to the acceleration sensor 316, respectively.

Explanation of Reference Signs

[0123] O Optical axis, 10 Lamp unit, 200 Vehicle lamp system, 226 Leveling actuator, 228, 228L, 228R Irradiation control unit, 228L1, 228R1 Receiving unit, 228L2, 228R2 Control unit, 228L3, 228R3 Transmitting unit, 236 Leveling control unit, 300 Vehicle, 316 Acceleration sensor.

Claims

1. A control device for a vehicle lamp having a function of controlling an illumination direction of a vehicle lamp in a vertical direction of a vehicle based on information on a vehicle attitude angle obtained from a detection value of an inclination detection device and information on a road surface angle, When the vehicle is moving straight at least one of when the vehicle starts and when the vehicle is stopped, a determination is made as to whether or not a road surface is horizontal based on a detection value of the inclination detection device and a motion acceleration of the vehicle; correcting the information about the road surface angle according to a result of the determination; A control device for vehicle lighting.

2. avoiding the execution of the correction when the vehicle is not moving straight at least either when the vehicle starts or when the vehicle stops; The vehicle lighting control device according to claim 1 .

3. Detecting whether the vehicle is moving straight based on a steering angle of the vehicle. The vehicle lighting control device according to claim 1 or 2.

4. detecting whether the vehicle is moving straight based on a detection value of the inclination detection device; The vehicle lighting control device according to claim 1 or 2.

5. the correction is performed when a difference between the square of the magnitude of the motion acceleration vector of the vehicle and the square of the magnitude of the detection value vector of the tilt detection device is equal to the square of the magnitude of the gravitational acceleration vector. The vehicle lamp control device according to any one of claims 1 to 4.

6. A vehicle lamp capable of adjusting the illumination direction in the vertical direction of the vehicle; The vehicle lighting control device according to any one of claims 1 to 5, Vehicle lighting system.

7. A method for controlling a vehicle lamp, the method comprising: controlling a direction of illumination of a vehicle lamp in a vertical direction of the vehicle based on information on a vehicle attitude angle obtained from a detection value of an inclination detection device and information on a road surface angle, the method comprising: When the vehicle is moving straight at least one of when the vehicle starts and when the vehicle is stopped, a determination is made as to whether or not a road surface is horizontal based on a detection value of the inclination detection device and a motion acceleration of the vehicle; and correcting information about the road surface angle according to a result of the determination. A method for controlling a vehicle lamp.

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