JP7322849B2 - headlight controller - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle headlamp control device that automatically controls the irradiation direction of a headlamp according to the pitch angle of a vehicle.

One of this type of headlight control devices (hereinafter also referred to as a "conventional device") is the amount of change in the height of the axle of the rear wheel (that is, It is equipped with a vehicle height sensor that detects the amount of relative displacement of the In addition, the conventional device obtains (estimates) the pitch angle based on the detected height change amount (see, for example, Patent Document 1). According to the conventional device, the pitch angle can be acquired without arranging vehicle height sensors on both the front and rear wheels of the vehicle.

JP-A-10-226271

However, even if the amount of change in height is the same, the pitch angles may differ. For example, even if the amount of change in height is the same, when a load is loaded behind the axle of the rear wheels (for example, in the rear trunk of a vehicle), it is compared to when the load is not loaded. Then the vehicle leans backward. In other words, even if the amount of change in height is the same, the positions of the centers of gravity of the occupants of the vehicle and the load of the vehicle including the load loaded on the vehicle (hereinafter also referred to as "vehicle load") are different. , the pitch angle of the vehicle changes. That is, depending on the position of the center of gravity of the load on the vehicle, the difference between the pitch angle estimated by the conventional device and the actual pitch angle may become relatively large.

By the way, there is known a vehicle equipped with a camera device that acquires a "moving direction image" by photographing an area in the moving direction of the vehicle. This type of vehicle has, for example, a driving support function that extracts a target appearing in a traveling direction image and automatically controls the speed and/or steering angle of the vehicle according to the type and position of the extracted target. offer.

SUMMARY OF THE INVENTION Accordingly, one of the objects of the present invention is to provide a headlight control device capable of accurately acquiring a pitch angle using a camera device mounted on a vehicle.

A headlight control device (hereinafter also referred to as "the device of the present invention") for achieving the above object includes an actuator, a controller, a vehicle height sensor, and a camera device.

The actuator (46) is
The irradiation angle (θb) of the headlight (low beam unit 31) of the vehicle (10) is changed.

The controller (headlight control ECU 20 and image processing unit 52)
A target irradiation angle (θbtgt) is obtained based on the pitch angle (θp) of the vehicle, and the actuator is controlled so that the irradiation angle matches the target irradiation angle (step 755 in FIG. 7).

The vehicle height sensor (61)
A relative displacement amount of the sprung member of the vehicle with respect to the rotating shaft of either the front wheel or the rear wheel of the vehicle is detected as the "contraction length (Ca)".

The camera device (50)
A "traveling direction image" is obtained by photographing an area in the traveling direction of the vehicle.

Further, the controller may
"Point at infinity (for example, point Pf in FIG. 4)" included in the moving direction image has a correlation with the "point at infinity (Yi)" which is the position in the vertical direction of the moving direction image. "Infinite point acquisition processing" for acquiring a correlation value (infinite point position Yi and current pitch angle θn) is executed.

Additionally, the controller may:
It is determined whether or not a predetermined "reference value acquisition condition" is established.

The controller is
When it is determined that the reference value acquisition condition is satisfied, the detected contraction length is added to a predetermined relationship between the contraction length and the pitch angle (the relationship represented by the straight line Le in FIG. 5). A reference pitch angle (θ std ) is obtained by applying a “reference value acquisition process” (steps 725 and 730 in FIGS. 7 and 10, and steps 925 and 730 in FIGS. 9 and 11).

On the other hand, the controller
When it is determined that the reference value acquisition condition is not satisfied, the pitch angle is acquired based on the reference pitch angle, the reference infinity point correlation value, and the current infinity point correlation value. Angle estimation processing” is executed (step 740 in FIGS. 7 and 10 and step 942 in FIGS. 9 and 11).

For example, if the position of the point at infinity (image base point) when the pitch angle is 0° (that is, when the vehicle is neither tilted forward nor backward) is acquired in advance, the position of the point at infinity at the present time and the image A pitch angle can be obtained based on the difference from the base point. The image base point can be acquired, for example, based on an image captured by setting a target object in front of a camera device in a factory where the vehicle was manufactured, and the positional relationship between the camera device and the target object.

However, since it is often difficult to accurately place the target object at a predetermined position in front of the camera device (i.e., the vehicle), the error in the acquired image origin may be relatively large. is high. On the other hand, it is possible to relatively accurately acquire the position of the point at infinity in the traveling direction image acquired while the vehicle is running by a well-known method. That is, it is possible to acquire the infinite point correlation value based on the traveling direction image. Therefore, according to the device of the present invention, the pitch angle can be accurately obtained based on the traveling direction image without providing vehicle height sensors for both the front and rear wheels of the vehicle.

In one aspect (first aspect) of the device of the present invention,
The controller is
When the detected contraction length is included in a predetermined "reference range" (range from the first contraction length C1 to the second contraction length C2), it is determined that the reference value acquisition condition is established.

The reference range in the device of the present invention is, for example, a contraction length range in which the pitch angle can be obtained with relatively high accuracy based on the contraction length. Additionally, the reference pitch angle and reference infinity point correlation values are obtained when the contraction length is within the reference range. Therefore, even when the contraction length is not included in the reference range, the pitch angle can be accurately obtained based on the reference pitch angle and the reference infinity point correlation value.

Therefore, according to the first aspect, the pitch angle can be acquired with high accuracy using the camera device mounted on the vehicle.

In a first aspect,
The controller is
The reference range may be set so as to be included in the range from the minimum value to the maximum value of the contraction length obtained when the vehicle carries only a driver (see FIG. 5). .

If the vehicle load is only the driver, the position of the center of gravity of the vehicle load remains substantially the same even if the driver's weight (that is, body weight) changes. Therefore, if the driver is the only load on the vehicle, the contracted lengths detected by the contracted length sensor are substantially the same. Therefore, according to this aspect, the reference pitch angle and the reference infinity point correlation value are obtained at the time when the difference between the pitch angle estimated based on the contraction length and the actual pitch angle is relatively small, and as a result, the pitch angle The estimation process makes it possible to obtain the pitch angle with high accuracy.

In another aspect (second aspect) of the device of the present invention,
The controller is
when the detected contraction length is smaller than "a value obtained by subtracting a predetermined difference threshold value (α) from the reference contraction length (Cstd)", it is determined that the reference value acquisition condition is satisfied;
When it is determined that the reference value acquisition condition is satisfied, the reference contraction length is updated so that the reference contraction length matches the detected contraction length.

During the period from the time when the vehicle first starts running (the time when the vehicle first starts running, that is, the time when the vehicle first runs after being manufactured) to the time when the condition for obtaining the reference value is met for the first time, the reference value acquisition process is not yet completed. Since it has not been executed, the pitch angle estimation process based on the reference pitch angle and the reference infinity point correlation value cannot be executed. Therefore, it is desirable that the period from the start of the first run to the first satisfaction of the reference value acquisition condition is short.

According to the second aspect, after the start of the first run, the contracted length is the initial value of the reference contracted length (that is, The reference value acquisition condition is established when the length becomes smaller than a value obtained by subtracting a predetermined difference threshold value from the reference contraction length. Therefore, according to this aspect, it is possible to shorten the period from the time when the vehicle starts running for the first time to the time when the reference value acquisition condition is satisfied for the first time.

In a second aspect,
The controller is
When the reference value acquisition process has not yet been executed, the reference contraction length is greater than "a value obtained by adding the difference threshold to the upper limit value (maximum contraction length Cmax) of the range of values for detecting the contraction length". It may be set to a large value (initial contraction length Ci).

According to this aspect, it is possible to more reliably shorten the period from the start of the first run to the first satisfaction of the reference value acquisition condition.

In another aspect (third aspect) of the device of the present invention,
The controller is
In the pitch angle estimation process,
The difference between the tangent of the pitch angle at the current time and the tangent of the reference pitch angle (tan(θp)−tan(θstd)) is the difference between the reference infinity point correlation value and the current infinity point correlation value ( Ystd-Yi), the pitch angle is obtained based on the relationship of being proportional to Ystd-Yi) (see equation (13)).

The infinite point correlation value is, for example, the vertical position (pixel position) of the "pixel corresponding to the infinite point" in the "moving direction image that is a set of pixels". This pixel position changes as the pitch angle changes (specifically, the tangent of the pitch angle). Therefore, according to the third aspect, it is possible to accurately acquire the pitch angle by a well-known calculation method using trigonometric functions.

In another aspect (fourth aspect) of the device of the present invention,
The controller is
In the pitch angle estimation process,
The difference between the current pitch angle and the reference pitch angle (pitch angle difference, θp-θstd) is the difference between the reference infinity point correlation value and the current infinity point correlation value (correlation value difference, Ystd- Yi) is proportional to the pitch angle (see formula (4)).

The pitch angle changes as the weight of the vehicle load and the position of the center of gravity change. However, in general, the magnitude of the pitch angle of the vehicle should not be excessive. Therefore, the pitch angle acquisition error caused by acquiring the pitch angle such that the pitch angle difference is proportional to the correlation value difference is relatively small. The constant of proportionality in this case is, for example, the angle of view angle (θa) representing the photographing range (angle of view) in the vertical direction of the camera device by "the number of pixels in the vertical direction constituting the traveling direction image (vertical resolution Yd)" is a value obtained by dividing Therefore, according to the fourth aspect, it is possible to obtain the pitch angle with relatively high accuracy through simple processing.

In another aspect (fifth aspect) of the device of the present invention,
The controller is
In the infinite point acquisition process,
A "specific point position at infinity (image base point Yo)", which is the position at infinity acquired when the pitch angle is a predetermined "specific angle (0°)", and the position at current point at infinity , obtains a value proportional to the difference (Yo-Yi) between , as the infinite point correlation value (current pitch angle θn),
In the reference value acquisition process,
A value obtained by adding the reference pitch angle to the difference (displacement pitch angle θfoe) between the infinity point correlation value and the reference infinity point correlation value (reference pitch angle θref) is obtained as the pitch angle (equation (9) ).

The specific angle is, for example, 0° (that is, the vehicle is neither tilted forward nor backward). The specific infinite point position is acquired, for example, based on the traveling direction image acquired while the vehicle is stopped. As described above, it is often difficult to accurately obtain the position of the point at infinity in the traveling direction image obtained when the vehicle is stationary.

On the other hand, in the fifth aspect, the contribution of the specific infinity point position to the difference between the reference infinity point correlation value and the current infinity point correlation value is canceled out. Therefore, according to the fifth aspect, even if it is difficult to accurately acquire the specific point at infinity, it is possible to acquire the pitch angle with high accuracy.

In the above description, in order to facilitate understanding of the present invention, names and/or symbols used in the embodiments are added in parentheses to configurations of the invention corresponding to the embodiments to be described later. However, each component of the present invention is not limited to the embodiments defined by the names and/or symbols. Other objects, features and attendant advantages of the present invention will be readily understood from the description of embodiments of the present invention described with reference to the following drawings.

1 is a side view of a vehicle (present vehicle) to which a headlamp control device (first control device) according to a first embodiment of the present invention is applied; 3 is a block diagram of a first control device; FIG. FIG. 2 is a diagram showing the structure of a low beam unit provided in the vehicle; It is an example of the front image image|photographed with the camera apparatus with which this vehicle is provided. It is a graph which showed the relationship between the detection value (contracted length) of the vehicle height sensor with which this vehicle is provided, and the pitch angle of this vehicle. (A) is a side view of the vehicle when the pitch angle is the reference pitch angle, and (B) is a side view of the vehicle when the pitch angle is different from the reference pitch angle. 4 is a flowchart showing an auto-leveling processing routine executed by the first control device; It is a figure referred in order to explain the process in which the headlamp control device (the 1st modification device) concerning the 1st modification of a 1st embodiment of the present invention acquires a pitch angle. 4 is a flowchart showing an auto-leveling processing routine executed by the first modified device; It is a flow chart showing an auto leveling processing routine which a headlamp control device concerning a 2nd embodiment of the present invention performs. It is a flowchart showing the auto-leveling process routine which the headlamp control apparatus based on the modification of 2nd Embodiment of this invention performs.

<First Embodiment>
Hereinafter, a headlamp control device (hereinafter also referred to as "first control device") according to a first embodiment of the present invention will be described with reference to the drawings. The first control device is applied to vehicle 10 shown in FIG. As can be seen from FIG. 2, which is a block diagram of the first control device, the first control device includes a headlamp control ECU 20, which is an Electronic Control Unit. Hereinafter, the headlight control ECU 20 is simply referred to as the ECU 20 as well.

The ECU 20 includes a microcomputer having a CPU 25, a ROM 26, a RAM 27 and a nonvolatile memory 28 as main elements. The CPU 25 sequentially executes predetermined programs (routines) to read data, perform numerical calculations, and output calculation results. The ROM 26 stores programs executed by the CPU 25 and lookup tables (maps) referenced when the programs are executed. RAM 27 temporarily stores data referred to by CPU 25 . The nonvolatile memory 28 is composed of a data rewritable flash memory, and stores data specific to the vehicle 10 (for example, a reference point at infinity Ystd and a reference pitch angle θstd, which will be described later).

The ECU 20 is connected to the headlights 30 , the camera device 50 , the vehicle height sensor 61 and the dimmer switch 62 .

The headlight 30 includes a low beam unit 31 and a high beam unit 32 . The low beam unit 31 includes a left low beam unit 31a and a right low beam unit 31b.

The irradiation range in the vertical direction (vertical direction) of the low beam unit 31 (that is, the left low beam unit 31a and the right low beam unit 31b) is the range between the straight line Lb1 and the straight line Lb2 in FIG. The dashed line Lba in FIG. 1 is the bisector of the angle between the straight lines Lb1 and Lb2.

The irradiation direction of the low beam unit 31 represented by the dashed line Lba is changed according to the pitch angle θp of the vehicle 10 by auto-leveling processing, which will be described later. More specifically, the pitch angle θp is defined by a “horizontal line” parallel to a plane including the ground contact points of the four wheels of the vehicle 10 and extending in the longitudinal direction of the vehicle 10 and the vehicle body of the vehicle 10 ( It is an angle formed by a "horizontal line of the vehicle body" extending in the longitudinal direction of the vehicle 10 and parallel to the sprung member.

In FIG. 1, the horizontal line Lh1 is the ground horizontal line, and the horizontal line Lh2 is the vehicle horizontal line. The angle formed by the horizontal line of the vehicle body and the dashed line Lba is also referred to as the irradiation angle θb. The auto-leveling process is a process of controlling the irradiation angle θb so that the angle formed by the dashed line Lba (that is, the irradiation direction of the low beam unit 31) and the ground horizontal line coincides with the predetermined glare-proof angle θh.

The pitch angle θp is an angle representing the extent to which the vehicle 10 (specifically, the sprung member) is tilted forward or backward. When the vehicle 10 is neither leaning forward nor leaning backward, the pitch angle θp is "0". Therefore, when the pitch angle θp is "0", the vehicle body horizontal line is parallel to the ground horizontal line.

The pitch angle θp takes a positive value when the vehicle 10 is tilting backward (that is, θp>0), and the pitch angle θp takes a negative value when the vehicle 10 is tilting forward (that is, θp< 0). In FIG. 1, the horizontal line Lh1 and the horizontal line Lh2 are parallel to each other, so the pitch angle θp is "0".

The structure of the left low beam unit 31a is shown in FIG. The structure of the right low beam unit 31b is the same as that of the left low beam unit 31a, so illustration thereof is omitted. The left low beam unit 31 a includes a bulb 41 , reflector 42 , upper rod 43 , lower rod 44 , unit case 45 and actuator 46 . The bulb 41 is fixed to the reflector 42 . Reflector 42 is supported by unit case 45 via upper rod 43 and lower rod 44 . The upper portion of reflector 42 is rotatably supported by the front end of upper rod 43 , and the lower portion of reflector 42 is rotatably supported by the front end of lower rod 44 . The unit case 45 is fixed to the vehicle body.

The length of the lower rod 44 is changed by the actuation of the actuator 46 (progress and retreat in the axial direction in the front-rear direction of the vehicle body), so that the reflecting mirror 42 swings in the vertical direction of the vehicle 10 . Specifically, when the lower rod 44 extends (that is, when its front end moves forward), the irradiation angle θb decreases and the area irradiated by the left low beam unit 31a moves upward. When the lower rod 44 contracts (that is, when its front end moves rearward), the illumination angle θb increases and the area illuminated by the left low beam unit 31a moves downward. As will be described later, the ECU 20 controls the actuator 46, thereby controlling the irradiation angle θb.

As shown in FIG. 1, the camera device 50 is arranged in the vicinity of a rearview mirror (not shown) arranged on the windshield of the vehicle 10 in the upper part of the passenger compartment. As shown in FIG. 2 , the camera device 50 includes an imaging section 51 and an image processing section 52 . The imaging unit 51 acquires a “front image” obtained by capturing an area in front of the vehicle 10 every time a predetermined time interval Δt elapses, and transmits information representing the front image (that is, still image data) to the image processing unit 52 . Output to

The imaging range (angle of view) in the vertical direction (vertical direction) of the imaging unit 51 is the range between the straight line Lc1 and the straight line Lc2 in FIG. The angle formed by the straight line Lc1 and the straight line Lc2 is the angle of view θa. The vertical (vertical) resolution of the front image (that is, the number of pixels forming the front image in the vertical direction) is the vertical resolution Yd. The forward image is also referred to as the "heading image" for convenience.

The image processing unit 52 processes the front image last acquired by the imaging unit 51 (the latest image) and the front image acquired immediately before the latest image (previous image, that is, the previous image acquired by the time interval Δt before the latest image). image) and a number of optical flow vectors (hereinafter also simply referred to as “flow vectors”) are obtained based on.

More specifically, the image processing unit 52 divides the previous image into rectangles of a predetermined size (that is, treats the previous image as a set of rectangles), and determines where each rectangle appears in the latest image. to explore. If the search succeeds, a flow vector is obtained that starts at the position of the rectangle in the previous image (source of movement) and ends at the position (destination) of the rectangle in the latest image. That is, the image processing unit 52 acquires flow vectors by a so-called block matching method.

When the flow vector is obtained, the image processing unit 52 obtains the infinite point position Yi representing the longitudinal position of the point of infinity (FOE) in the forward image (see FIG. 1). The point at infinity is a point representing the straight traveling direction of the vehicle 10 traveling on a flat road in the forward image. The infinity point position Yi is represented by the position of the pixel corresponding to the infinity point. When the point at infinity is at the lower end of the front image, the point at infinity position Yi is "1". When the point at infinity is at the upper end of the front image, the point at infinity position Yi is equal to the vertical resolution Yd.

The infinite point position Yi is also called an "infinite point correlation value" for convenience. For the sake of convenience, the process of acquiring the point position Yi at infinity is also referred to as "infinite point acquisition process".

A method of acquiring the point at infinity will be described. FIG. 4 shows an image 71, which is an example of a forward image acquired when the vehicle 10 is traveling straight. Point Pf in FIG. 4 indicates the point at infinity. Each arrow in image 71 represents a flow vector. The image 71 includes another vehicle 72 . The other vehicle 72 is traveling in a lane opposite to the lane in which the vehicle 10 is traveling (own lane) (that is, the opposite lane).

In the image 71, the "targets included in the image 71" other than the other vehicle 72 are stationary. As can be understood from FIG. 4, a straight line passing through the starting point and the ending point of "a flow vector whose starting point is not included in another vehicle 72 (that is, a flow vector whose starting point is included in a stationary target)" passes through the point Pf. In general, most of the targets included in the forward image are stationary, so most of the straight lines (vector extension lines) passing through the start and end points of the obtained flow vectors pass through the point Pf.

Therefore, the image processing unit 52 acquires a point through which a plurality of vector extension lines pass (that is, a point at which the vector extension lines intersect each other) and through which the largest number of vector extension lines pass as a point at infinity. The image processing unit 52 outputs the acquired infinity point position Yi to the ECU 20 each time the time interval Δt elapses.

In addition to the ECU 20, the vehicle 10 extracts various targets included in the front image (for example, the positions of other vehicles other than the vehicle 10, pedestrians, and own lane), and extracts the positions of the extracted targets. It is equipped with an ECU (driving assistance ECU) that provides a "driving assistance function" that assists the driver of the vehicle 10 based on the above. However, a description of the driving assistance function and the operation of the driving assistance ECU is omitted in this specification.

The vehicle height sensor 61 is provided in a rear wheel suspension device on the passenger seat side of the vehicle 10 (see FIG. 1). Specifically, since the vehicle 10 is a right-hand drive vehicle, the vehicle height sensor 61 is arranged in the suspension device for the left rear wheel. The vehicle height sensor 61 detects the amount of relative displacement of the sprung member of the vehicle 10 with respect to the rotation axis of the left rear wheel (that is, the mounting portion of the "left rear wheel suspension device" in the vehicle body of the vehicle 10 and the rotation axis of the left rear wheel). ) is detected as the contraction length Ca, and a signal representing the contraction length Ca is output to the ECU 20 . If the center-of-gravity position of the load of the vehicle 10 (that is, the vehicle load) including the occupants of the vehicle 10 and the load loaded on the vehicle 10 does not change, the contraction length Ca increases as the weight of the vehicle load increases. .

The dimmer switch 62 is used by the driver to select the lighting state of the headlamp 30 . The driver can switch the operating state of the dimmer switch 62 among "off position", "low beam position" and "high beam position".

When the dimmer switch 62 is in the low beam position, the ECU 20 turns on the low beam units 31 (that is, the left low beam unit 31a and the right low beam unit 31b). When the dimmer switch 62 is in the high beam position, the ECU 20 turns on the low beam unit 31 and the high beam unit 32 .

(auto-leveling processing)
The ECU 20 executes "auto-leveling processing" to keep the angle between the irradiation direction of the low beam unit 31 (that is, the dashed line Lba) and the horizontal line to the anti-glare angle θh even when the pitch angle θp changes. . That is, the ECU 20 acquires the pitch angle θp, and controls the irradiation angle θb based on the acquired pitch angle θp so that the relationship of the following formula (1) holds. Specifically, the ECU 20 obtains (calculates) the target irradiation angle θbtgt by substituting the obtained pitch angle θp into the following equation (1a), and calculates the target irradiation angle θbtgt so that the actual irradiation angle θb becomes equal to the target irradiation angle θbtgt. to control the actuator 46.

θb=θh+θp (1)
θbtgt=θh+θp (1a)

A method of obtaining the pitch angle θp will be described. When the reference infinity point position Ystd and the reference pitch angle θstd, which will be described later, have not yet been acquired, the ECU 20 determines the contraction length to the “relationship between the contraction length Ca and the estimated pitch angle θe” represented by the straight line Le in FIG. Obtain the estimated pitch angle θe by applying Ca. The relationship between the contraction length Ca represented by the straight line Le and the estimated pitch angle θe is stored in the ROM 26 in the form of a map (lookup table).

In this case, the ECU 20 substitutes the obtained estimated pitch angle θe as the pitch angle θp into the equation (1a) to calculate the target irradiation angle θbtgt. Additionally, the ECU 20 controls the actuator 46 so that the actual irradiation angle θb matches the target irradiation angle θbtgt. The ECU 20 stores the relationship between the drive amount of the actuator 46 and the irradiation angle θb in advance in the ROM 26, and the drive amount of the actuator 46 necessary for the irradiation angle θb to match the target irradiation angle θbtgt is calculated based on the relationship. The actuator 46 is driven by the calculated driving amount.

The straight line Le in FIG. 5 is a straight line that passes through the point Pa1 and is obtained so that the sum of the distances between the points Pa2 to Pa5 and the straight line Le is minimized (that is, by the method of least squares). A point Pa1 is the contraction length when an occupant (specifically, an occupant with a predetermined standard weight) is seated only in the driver's seat of the vehicle 10 (that is, when only the driver is on the vehicle 10). It represents the relationship between Ca and the pitch angle θp. A point Pa2 represents the relationship between the contraction length Ca and the pitch angle θp when the occupants are seated in the driver's seat and the passenger's seat.

A point Pa3 represents the relationship between the contraction length Ca and the pitch angle θp when all the seats of the vehicle 10 are occupied by passengers. A point Pa4 represents the relationship between the contraction length Ca and the pitch angle θp when all the seats are occupied by passengers and the rear trunk of the vehicle 10 is loaded with a predetermined weight of luggage. A point Pa5 represents the relationship between the contraction length Ca and the pitch angle θp when an occupant is seated only in the driver's seat and a cargo of a predetermined weight is loaded in the rear trunk.

As understood from the points Pa1 to Pa5, the contraction length Ca and the pitch angle θp are not in a monotonically increasing relationship. In other words, even if the contraction length Ca is the same, the pitch angle θp differs according to the position of the center of gravity of the vehicle load. Therefore, depending on the position of the center of gravity of the vehicle load, the estimated pitch angle θe obtained by applying the contracted length Ca to the “relationship between the contracted length Ca and the estimated pitch angle θe” represented by the straight line Le, and the actual pitch angle θe There is a possibility that the magnitude of the difference between the pitch angle θp and the pitch angle θp becomes relatively large.

Therefore, the ECU 20 acquires the pitch angle θp based on the infinite point position Yi by utilizing the monotonically decreasing relationship between the pitch angle θp and the infinite point position Yi. More specifically, the relationship between the pitch angle θp and the position at infinity Yi decreases as the pitch angle θp increases (that is, if the vehicle 10 tilts backward), the position at infinity Yi decreases (that is, the front image The point at infinity above moves down). When the pitch angle θp decreases (that is, the vehicle 10 leans forward), the point of infinity Yi increases (that is, the point of infinity on the forward image moves upward).

When the pitch angle θp is "0", the point position Yi at infinity becomes the image base point Yo. The image origin Yo is shown as a point on the line segment Lp representing the projection plane of the forward image in FIG. In other words, when the pitch angle θp is "0", the intersection (base intersection) between the horizontal line Lh2, which is the horizontal line of the vehicle body passing through the camera device 50 (specifically, the imaging unit 51), and the line segment Lp is This is the image base point Yo. That is, if the length of the line segment Lp is regarded as the vertical resolution Yd, the length from the lower end of the line segment Lp to the base point intersection corresponds to the image base point Yo.

The pitch angle θp of "0" is also called a "specific angle" for convenience. For the sake of convenience, the image base point Yo is also referred to as a "specific point position at infinity".

When the pitch angle .theta.p has a relatively small magnitude |.theta.p|

θp=θa×(Yo−Yi)/Yd (2)

The image base point Yo can be obtained in advance. For example, when the vehicle 10 is manufactured or the camera device 50 is replaced, a "target object" is installed at a predetermined position in front of the vehicle 10, and the pitch angle θp is "0". The image base point Yo can be obtained based on the front image in which the target is captured. However, in many cases, it is difficult to precisely perform the work of stopping the vehicle 10 at a predetermined position in a predetermined direction and setting the target object at a predetermined position in order to obtain the image base point Yo. , it is difficult to obtain the image base point Yo accurately.

On the other hand, as described above, in many cases, the forward image includes many stationary targets, so the infinity point position Yi is accurately acquired based on the forward image acquired while the vehicle 10 is traveling. be able to. Therefore, the ECU 20 acquires the pitch angle θp based on the position Yi of the point at infinity without depending on the image base point Yo.

More specifically, the ECU 20 determines the pitch angle θp based on the reference pitch angle θstd, which is the pitch angle θp, and the reference infinity point position Ystd, which is the infinity point position Yi when the pitch angle θp is the reference pitch angle θstd. to obtain the pitch angle θp. The reference infinity point position Ystd is also called a "reference infinity point correlation value" for the sake of convenience. The following formula (3) is obtained by substituting the reference pitch angle θstd and the reference infinity point position Ystd into the formula (2).

θstd=θa×(Yo−Ystd)/Yd (3)

FIG. 6A shows the vehicle 10 in a state where the pitch angle θp is the reference pitch angle θstd. The angle formed by the horizontal line Lh3, which is the horizontal line to the ground, and the straight line Lf1, which is the horizontal line of the vehicle body, is the reference pitch angle θstd (that is, the pitch angle θp in this case). In this example, the vehicle 10 is leaning forward, so the pitch angle θp is a negative value.

Furthermore, the following equation (4) is obtained by subtracting equation (3) from equation (2) (that is, by eliminating the image base point Yo).

θp−θstd=θa×(Ystd−Yi)/Yd (4)

FIG. 6B shows the vehicle 10 in a state where the pitch angle θp is different from the reference pitch angle θstd. The angle formed by the horizontal line Lh4, which is the horizontal line to the ground, and the straight line Lf2, which is the horizontal line of the vehicle body, is the pitch angle θp in this example. A straight line Lst1 in FIG. 6B is a straight line whose angle with the straight line Lf2 is the reference pitch angle θstd. In this example, the vehicle 10 is leaning backward, so the pitch angle θp is a positive value.

As can be understood from FIG. 6(B), equation (4) is the angle between the horizontal line Lh4 and the straight line Lst1 (θp−θstd), and the angle between the reference point at infinity Ystd and the point at infinity Yi. It represents the relationship between (Ystd-Yi), which is the difference.

The following formula (5) is obtained from the formula (4).

θp=θa×(Ystd−Yi)/Yd+θstd (5)

Therefore, according to equation (5), even if the image base point Yo cannot be obtained with high accuracy, the pitch angle θp can be obtained based on the infinite point position Yi.

Next, a method of obtaining the reference pitch angle θstd and the reference infinity point position Ystd will be described. When the vehicle is loaded with only the driver (that is, when there is an occupant only in the driver's seat of the vehicle 10 and the vehicle 10 is not loaded with cargo), the contraction length Ca is The values are approximately the same. In other words, even if the driver's weight changes as a result of driver change, the amount of change in the contraction length Ca is small and the center of gravity of the vehicle load remains substantially the same.

Therefore, the ECU 20 acquires the combination of the estimated pitch angle θe and the infinite point position Yi when the driver is the only load on the vehicle as the combination of the reference pitch angle θstd and the reference infinite point position Ystd.

Specifically, the ECU 20 determines the estimated pitch obtained by applying the contraction length Ca in the case where the vehicle load is only the driver to the "relationship between the contraction length Ca and the estimated pitch angle θe" represented by the straight line Le. The angle θe is stored in the nonvolatile memory 28 as the reference pitch angle θstd. In addition, the ECU 20 stores the infinity point position Yi in this case in the nonvolatile memory 28 as the reference infinity point position Ystd.

Note that the reference pitch angle θstd and the reference infinity point position Ystd are not stored in the nonvolatile memory 28 at the time the vehicle 10 is manufactured. Additionally, when the camera device 50 is replaced or repaired, the reference pitch angle θstd and the reference infinity point position Ystd are erased from the nonvolatile memory 28 .

When the contracted length Ca is greater than a predetermined first contracted length C1 and smaller than a second predetermined contracted length C2 (C1<Ca<C2), the ECU 20 determines that the driver is the only vehicle load. For the sake of convenience, the range of the contracted length Ca from the first contracted length C1 to the second contracted length C2 is also called a "reference range". For the sake of convenience, the condition that is satisfied when the contraction length Ca is within the reference range is also referred to as the "reference value acquisition condition".

(Specific action)
Next, specific operations of the ECU 20 relating to the auto-leveling process will be described. The CPU 25 of the ECU 20 (hereinafter also simply referred to as "CPU") executes an "auto-leveling processing routine" shown in the flowchart of FIG. 7 each time a predetermined time smaller than the time interval Δt elapses.

Therefore, at an appropriate timing, the CPU starts the process from step 700 in FIG. 7, proceeds to step 705, and determines whether or not the infinite point position Yi is newly received. That is, the CPU determines whether or not the infinity point position Yi has been received from the camera device 50 during the period from when this routine was last executed to the present time.

If the CPU has not newly received the infinity point position Yi, it determines "No" in step 705, proceeds directly to step 795, and terminates the processing of this routine.

On the other hand, if the CPU has newly received the infinite point position Yi, the CPU determines “Yes” in step 705 and proceeds to step 710 to acquire the contraction length Ca detected by the vehicle height sensor 61 . The CPU then proceeds to step 715 to obtain the estimated pitch angle θe by applying the contraction length Ca to the "relationship between the contraction length Ca and the estimated pitch angle θe" represented by the straight line Le in FIG.

Further, the CPU proceeds to step 720 to determine whether the contracted length Ca is within the range from the first contracted length C1 to the second contracted length C2 (that is, whether the contracted length Ca is included in the reference range). judge.

If the contraction length Ca is included in the range from the first contraction length C1 to the second contraction length C2, the CPU determines "Yes" in step 720, proceeds to step 725, and sets the infinite point position Yi. It is stored in the non-volatile memory 28 as the reference infinity point position Ystd. Next, the CPU proceeds to step 730 and stores the estimated pitch angle θe in the nonvolatile memory 28 as the reference pitch angle θstd. For the sake of convenience, the process of acquiring the reference pitch angle θstd and the reference infinity point position Ystd (that is, the reference infinity point correlation value) is also referred to as a “reference value acquisition process”. Furthermore, the CPU proceeds to step 735 .

On the other hand, if the contracted length Ca is not within the range from the first contracted length C1 to the second contracted length C2, the CPU makes a “No” determination in step 720 and proceeds directly to step 735 .

At step 735, the CPU determines whether or not the reference point position Ystd at infinity and the reference pitch angle θstd have been acquired. That is, the CPU determines whether or not the reference infinity point position Ystd and the reference pitch angle θstd are stored in the nonvolatile memory 28 .

If the reference point at infinity Ystd and the reference pitch angle θstd have been acquired, the CPU determines “Yes” in step 735 and proceeds to step 740 to obtain the reference point at infinity Ystd, the reference pitch angle θstd, and the infinity point. A pitch angle θp is obtained based on the far point position Yi. Specifically, the CPU obtains (calculates) the pitch angle θp by substituting the reference infinity point position Ystd, the reference pitch angle θstd, and the infinity point position Yi into the above equation (5). For convenience, the process of obtaining the pitch angle θp based on the reference infinity point position Ystd, the reference pitch angle θstd, and the infinity point position Yi is also called "pitch angle estimation process". The CPU then proceeds to step 750 .

On the other hand, if the reference infinity point position Ystd and the reference pitch angle θstd have not been acquired, the CPU determines “No” in step 735 and proceeds to step 745 to set the pitch angle θp to a value equal to the estimated pitch angle θe. to get as The CPU then proceeds to step 750 .

At step 750, the CPU determines whether the low beam unit 31 is on. That is, the CPU determines whether the operation state of the dimmer switch 62 is either the low beam position or the high beam position.

If the low beam unit 31 is on, the CPU makes a "Yes" determination in step 750, proceeds to step 755, and controls the irradiation angle θb. More specifically, the CPU obtains (calculates) the target irradiation angle θbtgt by substituting the pitch angle θp into the above equation (1a). Additionally, the CPU controls the actuator 46 so that the actual irradiation angle θb matches the target irradiation angle θbtgt. The CPU then proceeds to step 795 .

On the other hand, if the low beam unit 31 is not lit, the CPU determines “No” at step 750 and proceeds directly to step 795 .

(First Modification of First Embodiment)
Next, a headlamp control device (hereinafter also referred to as "first modified device") according to a first modified example of the first embodiment of the present invention will be described. The first control device described above obtains the pitch angle θp based on the reference infinity point position Ystd and the reference pitch angle θstd obtained when the contraction length Ca is within the reference range. On the other hand, the first deformation device obtains the pitch angle θp based on the reference pitch angle θstd and the reference pitch angle θref obtained when the contraction length Ca is within the reference range. This difference will be mainly described below.

The headlamp control ECU 21 (hereinafter also simply referred to as the ECU 21) according to the first modified device operates when the contraction length Ca is within the reference range (that is, when the vehicle load is only the driver). determined), the reference pitch angle θstd and the reference pitch angle θref are acquired and stored in the nonvolatile memory 28 . The reference pitch angle θref is also called a “reference infinity point correlation value” for convenience. When the contraction length Ca is not within the reference range, the ECU 21 obtains the pitch angle θp based on the reference pitch angle θstd and the reference pitch angle θref.

A specific description will be given with reference to FIG. When the contraction length Ca is included in the reference range, the ECU 21 substitutes the infinity point position Yi and the image base point Yo obtained in advance and stored in the nonvolatile memory 28 into the following equation (6). Calculate the pitch angle θn. The current pitch angle θn is also called an “infinite point correlation value” for convenience. Equation (6) expresses a relationship similar to Equation (2) described above.

θn=θa×(Yo−Yi)/Yd (6)

In addition, the ECU 21 acquires the current pitch angle θn as the reference pitch angle θref. If the infinite point position Yi in this case is treated as the reference infinite point position Ystd, the relationship of the following formula (7) holds.

θref=θa×(Yo−Ystd)/Yd (7)

Furthermore, the ECU 21 obtains the estimated pitch angle θe by applying the contraction length Ca to the "relationship between the contraction length Ca and the estimated pitch angle θe" represented by the straight line Le. In addition, the ECU 21 acquires the estimated pitch angle θe as the reference pitch angle θstd.

FIG. 8 shows an example in which the contraction length Ca is not included in the reference range after the reference pitch angle θstd and the reference pitch angle θref have been acquired. The pitch angle θp in this example is the angle between the horizontal line Lh5, which is the horizontal line to the ground, and the straight line Lf3, which is the horizontal line of the vehicle body. A straight line Lst2 in FIG. 8 is a straight line whose angle with the straight line Lf3 is the reference pitch angle θstd. In this example, the vehicle 10 is leaning backward, so the pitch angle θp is a positive value.

When the contraction length Ca is not within the reference range, the ECU 21 calculates the current pitch angle θn based on the formula (6), and substitutes the current pitch angle θn into the following formula (8) to obtain the displaced pitch angle. Calculate θfoe. The displacement pitch angle θfoe represents the angle formed by the horizontal line Lh5 and the straight line Lf3. In other words, the displacement pitch angle θfoe corresponds to the difference between the pitch angle θp at the time when the above-described standard pitch angle θstd and reference pitch angle θref are obtained and the current pitch angle θp.

θfoe=θn−θref (8)

In addition, the ECU 21 acquires (calculates) the pitch angle θp based on the following formula (9).

θp=θfoe+θstd (9)

Here, the reason why the pitch angle θp is acquired using the displacement pitch angle θfoe will be described. The following formula (10) is obtained from formulas (6) to (9).

θp=(θn−θref)+θstd
= {θa×(Yo−Yi)/Yd−θa×(Yo−Yref)/Yd}
+θstd (10)

There is a high possibility that the reference pitch angle θstd obtained when it is determined that the vehicle's load is only the driver has a small difference from the actual pitch angle θp at that time. On the other hand, since the reference pitch angle θref obtained at the same timing as the reference pitch angle θstd is calculated based on the image base point Yo, the magnitude of the difference from the actual pitch angle θp at that time is relatively large. there is a possibility.

Furthermore, since the current pitch angle θn acquired at the present time is calculated based on the image base point Yo in the same way as the reference pitch angle θref, the magnitude of the difference from the actual pitch angle θp at the present time may be relatively large. have a nature. However, since the displacement pitch angle θfoe is obtained as the difference between the current pitch angle θn and the reference pitch angle θref at this time, the error caused by the accuracy of obtaining the image reference point Yo is canceled out.

In other words, the displacement pitch angle θfoe accurately represents the difference between the current pitch angle θp and the reference pitch angle θstd. Therefore, according to the first modification device, even if the image base point Yo is not obtained with high accuracy, the current pitch angle θp can be obtained with high accuracy based on Equation (9).

(Specific operation)
Next, a specific operation of the ECU 21 relating to the auto-leveling process will be described. The CPU 25 of the ECU 21 (hereinafter also simply referred to as "CPU") executes an "auto-leveling processing routine" shown in the flowchart of FIG. 9 each time a predetermined time shorter than the time interval Δt elapses.

It should be noted that the steps shown in the flowchart of FIG. 9 in which the same processing as the steps shown in the flowchart of FIG. 7 are executed are given the same step symbols as in FIG.

When the appropriate timing comes, the CPU starts processing from step 900 in FIG. 9 and proceeds to step 705 . After executing the process of step 715, the CPU proceeds to step 917 and calculates the current pitch angle θn based on the above equation (6) (that is, based on the image base point Yo and the infinite point position Yi). The CPU then proceeds to step 720 .

If the CPU determines "Yes" in step 720 (that is, if the contraction length Ca is included in the reference range), the process proceeds to step 925, and the current pitch angle θn is stored in the nonvolatile memory 28 as the reference pitch angle θref. Remember. Next, the CPU proceeds to step 730 and stores the estimated pitch angle θe in the nonvolatile memory 28 as the reference pitch angle θstd. For the sake of convenience, the process of acquiring the reference pitch angle θstd and the reference pitch angle θref (that is, the reference infinity point correlation value) is also referred to as "reference value acquisition process". Furthermore, the CPU proceeds to step 935 .

On the other hand, if the CPU determines “No” in step 720 , the process proceeds directly to step 935 .

At step 935, the CPU determines whether or not the reference pitch angle θstd and the reference pitch angle θref have been acquired. That is, the CPU determines whether or not the reference pitch angle θstd and the reference pitch angle θref are stored in the nonvolatile memory 28 .

If the reference pitch angle θstd and the reference pitch angle θref have been acquired, the CPU determines “Yes” in step 935, proceeds to step 940, and acquires the displacement pitch angle θfoe based on the above equation (8). . Next, the CPU proceeds to step 942 and acquires the pitch angle θp based on Equation (9) above. For convenience, the process of obtaining the pitch angle θp based on the reference pitch angle θref, the reference pitch angle θstd, and the current pitch angle θn is also called “pitch angle estimation process”. Furthermore, the CPU proceeds to step 750 .

On the other hand, if the reference pitch angle θstd and the reference pitch angle θref have not been acquired, the CPU makes a “No” determination in step 935 and proceeds to step 745 .

(Second Modification of First Embodiment)
Next, a headlamp control device according to a second modification of the first embodiment of the present invention (hereinafter also referred to as a "second modification device") will be described. The above-described first control device acquires the pitch angle θp based on the above-described formula (5). On the other hand, the second deformation device differs only in that it obtains the pitch angle θp based on the following equation (14). Therefore, the following description will focus on this point of difference.

As can be seen from the right triangle defined by the horizontal line Lh4, the straight line Lf2 and the line segment Lp (the angle formed by the horizontal line Lh4 and the line segment Lp is a right angle) in FIG. 6B, the pitch angle θp, The relationship of the following equation (11) holds between the image base point Yo and the infinite point position Yi. In equation (11), K is a positive constant.

tan(θp)=K×(Yo-Yi) (11)

The following equation (12) is obtained by substituting the reference pitch angle θstd and the reference infinity point position Ystd into the equation (11).

tan(θstd)=K×(Yo-Ystd) (12)

Furthermore, the following equation (13) is obtained by subtracting equation (12) from equation (11) (that is, by eliminating the image base point Yo). Therefore, the pitch angle θp can be obtained based on the following formula (14). More specifically, when executing the processing of step 740 in FIG. 7, the headlight control ECU 22 relating to the second modified device sets the reference infinity point position Ystd, the reference pitch angle θstd, and the infinity point position Yi to The pitch angle θp is obtained (calculated) by substituting into Equation (14).

tan(θp)−tan(θstd)=K×(Ystd−Yi) (13)
tan(θp)=K×(Ystd−Yi)+tan(θstd) (14)

<Second embodiment>
Next, a second embodiment of the invention will be described. The above-described first control device obtains the reference infinity point position Ystd and the reference pitch angle θstd when the contraction length Ca is within the reference range. On the other hand, the headlamp control device according to the second embodiment (hereinafter also referred to as “second control device”) is configured such that the contraction length Ca is “a predetermined difference threshold value α (positive constant) from the reference contraction length Cstd”. (that is, Ca<Cstd−α), the reference point position Ystd at infinity and the reference pitch angle θstd are acquired. This difference will be mainly described below.

The reference contraction length Cstd is the contraction length Ca when the reference infinity point position Ystd and the reference pitch angle θstd are obtained. In other words, each time the contraction length Ca becomes smaller than "the value obtained by subtracting the difference threshold value α from the reference contraction length Cstd", the reference point at infinity Ystd and the reference pitch angle θstd are newly acquired (updated), In addition, the contraction length Ca at that time is newly acquired (updated) as the reference contraction length Cstd. For the sake of convenience, the condition that holds when the contraction length Ca is smaller than "the value obtained by subtracting the difference threshold value α from the reference contraction length Cstd" is also referred to as the "reference value obtaining condition".

The reference contraction length Cstd stored in the nonvolatile memory 28 at the time the vehicle 10 is manufactured is equal to the predetermined contraction length initial value Ci. The contraction length initial value Ci is a value larger than "the value obtained by adding the difference threshold α to the maximum contraction length Cmax" (that is, Cmax+α<Ci). The maximum contraction length Cmax is a value substantially equal to the upper limit of the range of contraction length Ca detected by the vehicle height sensor 61 (see FIG. 5). Note that when the camera device 50 is replaced or repaired, the reference contraction length Cstd is set to the contraction length initial value Ci.

Since the contracted length Ca acquired when the vehicle 10 is running for the first time after being manufactured is smaller than "the value obtained by subtracting the difference threshold α from the contracted length initial value Ci", the reference value acquisition condition holds. Therefore, at this time, the contraction length Ca is obtained (stored) as the reference contraction length Cstd, and the reference infinity point position Ystd and the reference pitch angle θstd are also obtained. After that, when the contraction length Ca becomes smaller than "the value obtained by subtracting the difference threshold α from the reference contraction length Cstd", the reference infinity point position Ystd and the reference pitch angle θstd are newly acquired.

The difference threshold α is, for example, set to a value smaller than the amount of change in the contraction length Ca when the number of passengers decreases, and even though the vehicle load has not changed, the vehicle 10 is running. is determined in advance so that the reference value acquisition condition is not repeatedly satisfied.

(Specific operation)
A specific operation of the headlight control ECU 23 (hereinafter also simply referred to as the ECU 23) related to the second control device will be described. The CPU 25 of the ECU 23 (hereinafter also simply referred to as "CPU") executes an "auto-leveling processing routine" shown in the flowchart of FIG. 10 each time a predetermined time smaller than the time interval Δt elapses.

The steps shown in the flow chart of FIG. 10 in which the same processes as those shown in the flow chart of FIG. 7 are executed are given the same step symbols as in FIG.

When the appropriate timing comes, the CPU starts processing from step 1000 in FIG. 10 and proceeds to step 705 . After executing the process of step 715, the CPU proceeds to step 1020 and determines whether or not the contraction length Ca is smaller than "a value obtained by subtracting the difference threshold α from the reference contraction length Cstd".

If the contraction length Ca is smaller than "the value obtained by subtracting the difference threshold value α from the reference contraction length Cstd", the CPU determines "Yes" in step 1020, proceeds to step 1022, and uses the contraction length Ca as the reference contraction value. It is stored in the non-volatile memory 28 as the length Cstd. The CPU then proceeds to step 725 .

On the other hand, if the contraction length Ca is equal to or greater than "the value obtained by subtracting the difference threshold value α from the reference contraction length Cstd", the CPU determines "No" in step 1020 and proceeds directly to step 735. FIG.

When the processing of step 755 ends, the CPU proceeds to step 1095 and ends the processing of this routine. In addition, if the determination condition of step 705 is not satisfied (that is, if the infinite point position Yi is not newly received), the determination in step 705 is “No” and the process proceeds directly to step 1095 .

(Modification of Second Embodiment)
Next, a headlamp control device (hereinafter also referred to as "third modified device") according to a modified example of the second embodiment of the present invention will be described. The second control device described above obtains the pitch angle θp based on the reference infinity point position Ystd and the reference pitch angle θstd obtained when the reference value obtaining condition is satisfied. On the other hand, the third transforming device acquires the pitch angle θp based on the reference pitch angle θstd and the reference pitch angle θref acquired when the standard value acquisition condition is satisfied, similarly to the above-described first transforming device. .

The CPU 25 (hereinafter also simply referred to as "CPU") of the headlight control ECU 24 (hereinafter simply referred to as "ECU 24") according to the third modified device operates as an "automatic Leveling processing routine” is executed each time a predetermined time smaller than the time interval Δt elapses.

The steps shown in the flowchart of FIG. 11 in which the same processing as the steps shown in the flowchart of FIG. 7 are executed are given the same step symbols as in FIG. Similarly, the steps shown in the flow chart of FIG. 11 in which the same processing as the steps shown in the flow chart of FIG. 9 or 10 are executed are assigned the same step symbols as in FIG. 9 or 10. It is

When the appropriate timing comes, the CPU starts processing from step 1100 in FIG. 11 and proceeds to step 705 . After executing the process of step 917 , the CPU proceeds to step 1020 . After executing the process of step 1022 , the CPU proceeds to step 925 .

When the processing of step 755 ends, the CPU proceeds to step 1195 and ends the processing of this routine. In addition, if the determination condition of step 705 is not satisfied (that is, if the infinite point position Yi is not newly received), the CPU determines "No" in step 705 and directly proceeds to step 1195. move on.

As described above, the first control device and the second control device control the pitch angle θp based on the contraction length Ca acquired by the vehicle height sensor 61 and the infinity point position Yi acquired by the camera device 50. can be obtained. In other words, according to the first control device and the second control device, even if the vehicle height sensor 61 is arranged only in the suspension device of the rear wheels of the vehicle 10, the camera device 50 for providing the driving assistance function can be used to obtain the pitch angle θp.

In particular, according to the first control device (and the first deformation device and the second deformation device), based on the reference pitch angle and the reference infinity point correlation value obtained when the contraction length Ca is included in the reference range, It becomes possible to obtain the pitch angle θp with high accuracy. According to the second control device (and the third modified device), the reference pitch angle and the reference infinity point correlation value are obtained early after the vehicle 10 is manufactured. It is possible to increase the chances of obtaining the pitch angle θp based on the value.

Although the embodiments of the headlamp control device according to the present invention have been described above, the present invention is not limited to the above embodiments, and various modifications are possible without departing from the object of the present invention. For example, in the present embodiment, the image processing unit 52 acquires the infinite point position Yi. However, the infinite point position Yi may be acquired by the ECU 20 . In this case, the image processing unit 52 outputs information representing the forward image (that is, still image data) to the ECU 20 each time the time interval Δt elapses.

In addition, the image processing unit 52 according to the present embodiment outputs the infinite point position Yi to the ECU 20 each time the time interval Δt elapses. However, the image processing unit 52 is configured not to output the infinite point position Yi to the ECU 20 when the infinite point position Yi cannot be obtained with high accuracy (for example, when the vehicle 10 is stopped). May be.

In addition, the ECU 20 associated with the first control device, regardless of whether the contraction length Ca is included in the reference range, if the reference infinity point position Ystd and the reference pitch angle θstd are acquired (that is, FIG. 7 4), the pitch angle θp is obtained based on the reference point position Ystd, the reference pitch angle θstd, and the point position Yi. That is, in this case, the ECU 20 was executing the process of step 740 . However, the ECU 20 may acquire the pitch angle θp by a process different from step 740 when the contraction length Ca is within the reference range. For example, in this case, the ECU 20 may acquire the pitch angle θp as a value equal to the estimated pitch angle θe acquired by the process of step 715 .

In addition, the ECU 20 associated with the first control device determines that the vehicle load is only the driver when the contracted length Ca is greater than the first contracted length C1 and smaller than the second contracted length C2. In other words, the first contraction length C1 is determined to substantially match the lower limit of the range of values for the contraction length Ca when the vehicle load is the driver alone. However, the first contracted length C1 may be set to substantially match the value of the contracted length Ca when there is no load on the vehicle.

In addition, the ECU 23 related to the second control device acquires the pitch angle θp by substituting the reference point of infinity Ystd, the reference pitch angle θstd, and the point of infinity Yi into the above equation (5) (Fig. 10, step 740). However, the ECU 23 may obtain the pitch angle θp by substituting the reference infinity point position Ystd, the reference pitch angle θstd, and the infinity point position Yi into Equation (14).

In addition, the "specific angle" in this embodiment was "0". However, the "specific angle" may be a value other than "0". In this case, the image origin Yo is the infinity point position Yi obtained when the pitch angle θp is that particular angle (different from "0").

In addition, the difference threshold α in the second embodiment was a predetermined positive value. However, the difference threshold α may be "0".

In addition, when the contraction length Ca is included in the reference range, the ECU 20 associated with the first control device applies the contraction length Ca to the "relationship between the contraction length Ca and the estimated pitch angle θe" represented by the straight line Le. Thus, the reference pitch angle θstd is obtained. However, when the contraction length Ca is within the reference range, the ECU 20 acquires the reference pitch angle θstd based on the “relationship between the contraction length Ca and the estimated pitch angle θe” that differs from the relationship represented by the straight line Le. can be

In this case, for example, the ECU 20 may, in addition to the relationship represented by the straight line Le, obtain a plurality of "contraction length The non-volatile memory 28 stores the “relationship (specific relationship) between the contraction length Ca and the estimated pitch angle θe” obtained based on the “combination of Ca and the pitch angle θp”. In addition, the ECU 20 may obtain the reference pitch angle θstd by applying the contraction length Ca to the specific relationship when the contraction length Ca is within the reference range.

In addition, in this embodiment, the irradiation angle θb is changed by operating the actuator 46 . However, the irradiation angle θb may be changed by a method different from this. For example, in the low beam unit 31, by changing the position of the shielding plate arranged in front of the bulb 41, the area irradiated with the light of the bulb 41 is changed, and as a result, the irradiation angle θb is changed. may be configured.

In addition, the vehicle height sensor 61 according to the present embodiment is arranged in the rear wheel suspension device on the passenger seat side of the vehicle 10 . However, two vehicle height sensors may be provided in suspension devices provided on each of the rear wheels of the vehicle 10 . In this case, the ECU 20 may obtain the average value of the values detected by the two vehicle height sensors as the contraction length Ca. Alternatively, the vehicle height sensor 61 may be arranged in a suspension device for the front wheels of the vehicle 10 .

In addition, the first control device and the second control device acquire the pitch angle θp regardless of whether the low beam unit 31 is on. However, the ECU 20 may acquire the pitch angle θp only when the low beam unit 31 is on.

In addition, the camera device 50 according to this embodiment photographs an area in front of the vehicle 10 . However, the camera device 50 may be arranged in the vehicle 10 so as to capture an area behind the vehicle 10 in addition to the area in front of the vehicle 10 .

DESCRIPTION OF SYMBOLS 10... Vehicle, 20... Headlight control ECU, 23... CPU, 24... ROM, 25... RAM, 26... Non-volatile memory, 30... Headlight, 31... Low beam unit, 31a... Left low beam unit, 31b... Right Low beam unit 32 High beam unit 41 Bulb 42 Reflector 43 Upper rod 44 Lower rod 45 Unit case 46 Actuator 50 Camera device 51 Imaging section 52 Image processing Part, 61... vehicle height sensor, 62... dimmer switch.

Claims (8)

an actuator that changes the irradiation angle of the headlight of the vehicle;
a controller that acquires a target irradiation angle based on the pitch angle of the vehicle and controls the actuator so that the irradiation angle matches the target irradiation angle;
A headlight control device comprising:
a vehicle height sensor that detects a relative displacement amount of a sprung member of the vehicle with respect to a rotating shaft of one of the front wheels and the rear wheels of the vehicle as a contraction length;
a camera device that acquires a traveling direction image by photographing an area in the traveling direction of the vehicle;
with
The controller is
Execute an infinite point acquisition process for acquiring an infinite point correlation value having a correlation with an infinite point position, which is a position of an infinite point included in the traveling direction image in the vertical direction of the traveling direction image,
Determining whether or not a predetermined reference value acquisition condition is satisfied,
obtaining a reference pitch angle by applying the detected contraction length to a predetermined relationship between the contraction length and the pitch angle when it is determined that the reference value acquisition condition is satisfied; , executing a reference value acquisition process for acquiring the infinity point correlation value at that time as a reference infinity point correlation value,
Pitch angle for acquiring the pitch angle based on the reference pitch angle, the reference infinity point correlation value, and the current infinity point correlation value when it is determined that the reference value acquisition condition is not satisfied. perform the estimation process,
A headlight control device configured to: The headlamp control device according to claim 1,
The controller is
A headlamp control device configured to determine that the reference value acquisition condition is satisfied when the detected contraction length is within a predetermined reference range. In the headlamp control device according to claim 2,
The controller is
The headlamp control device, wherein the reference range is set to be included in the range from the minimum value to the maximum value of the contraction length obtained when the load of the vehicle is only a driver. The headlamp control device according to claim 1,
The controller is
determining that the reference value acquisition condition is satisfied when the detected contraction length is smaller than a value obtained by subtracting a predetermined difference threshold from the reference contraction length;
when it is determined that the reference value acquisition condition is satisfied, updating the reference contraction length so that the reference contraction length matches the detected contraction length;
A headlight control device configured to: In the headlamp control device according to claim 4,
The controller is
When the reference value acquisition process has not yet been executed, the reference contraction length is set to a value greater than the sum of the difference threshold and the upper limit of the range of values for detecting the contraction length. A headlight control device configured to: In the headlamp control device according to any one of claims 1 to 5,
The controller is
In the pitch angle estimation process, the difference between the current tangent of the pitch angle and the current tangent of the reference pitch angle is proportional to the difference between the reference infinity point correlation value and the current infinity point correlation value. obtain the pitch angle of interest based on
A headlight control device configured to: In the headlamp control device according to any one of claims 1 to 5,
The controller is
In the pitch angle estimation process, the difference between the current pitch angle and the reference pitch angle is proportional to the difference between the reference infinity point correlation value and the current infinity point correlation value. to get the pitch angle,
A headlight control device configured to: In the headlamp control device according to any one of claims 1 to 5,
The controller is
Proportional to the difference between the specific infinite point position, which is the infinite point position obtained when the pitch angle is a predetermined specific angle, and the current infinite point position in the infinite point obtaining process obtain a value for the point correlation value at infinity,
In the reference value obtaining process, a value obtained by adding the reference pitch angle to a difference between the infinity point correlation value and the reference infinity point correlation value is obtained as the pitch angle.
A headlight control device configured to:

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