JP4726277B2 - Automatic headlamp optical axis adjustment device for vehicles - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simplify a system structure that adjusts the optical axis direction of a headlight taking consideration of a static and dynamic change in vehicle attitude, and even a change in occupants during a stop, and the like. SOLUTION: The optical axis direction of a vehicle headlight is adjusted by an actuator driven based on a control angle θact calculated from an estimated road surface inclination θRe obtained, by an estimated pitch angle θpe estimated from the acceleration of a differentiated vehicle speed V and, an absolute inclination θa from one inclinometer disposed in the vehicle. A change, if any, in the absolute inclination θ during a vehicle stop is presumed to be a result of a change in occupants, and the estimated road surface inclination θRe is corrected accordingly. The static and dynamic change in vehicle attitude and even the change in occupants during a stop, and the like are taken into consideration, and the system structure of adjusting the optical axis direction of the headlight can be simplified to realize a cost reduction.

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a vehicle headlamp optical axis direction automatic adjustment device for automatically adjusting the optical axis direction of irradiation by a headlamp disposed in a vehicle.
[0002]
[Prior art]
Conventionally, a pitch angle corresponding to an inclination angle of a vehicle is generally obtained by detecting a vehicle height value before and after the vehicle with a vehicle height sensor and calculating the pitch angle based on these vehicle height values. However, the vehicle height sensor needs to be disposed on the axle. In particular, it is difficult to mount the vehicle height sensor on the front wheel, which is a steering wheel, and the system configuration is complicated and expensive.
[0003]
Therefore, a method for obtaining the vehicle pitch angle using an inclinometer in place of the vehicle height sensor is desired. Here, in order to adjust the optical axis direction of the headlamp, it is necessary to control in consideration of the road surface inclination angle, but when the absolute inclination angle from the inclinometer is used, it is necessary to correct the road surface inclination angle. Become.
[0004]
As prior art documents related to this, those disclosed in Japanese Patent Application Laid-Open No. 10-324192 and Japanese Patent No. 2767220 are known.
[0005]
Among them, in Japanese Patent Application Laid-Open No. 10-324192, the influence of the road surface inclination due to a slope or the like is measured using two inclinometers, two between the suspension arms and the body in front of the vehicle and one on the body. A technique for adjusting the optical axis direction of a headlight of a vehicle while avoiding it is shown. In Japanese Patent No. 2767220, a dynamic pitch angle change of the vehicle is obtained by the acceleration of the vehicle, and a vehicle headlamp is taken into account by taking a static attitude change of the vehicle due to gravity on a slope with an inclinometer. A technique for adjusting the optical axis direction of the lamp is shown.
[0006]
[Problems to be solved by the invention]
By the way, in the former of the above-mentioned prior art documents, two inclinometers are disposed on the suspension part of the vehicle, and are subject to mounting restrictions, etc., similar to those using a conventional vehicle height sensor. At the same time, three inclinometers are necessary, and there is a problem that an expensive system configuration is unavoidable.
[0007]
In the latter case, it is described that a change in the vehicle's static attitude is taken into account, but the influence of changes in the occupant during driving or when the vehicle is stopped is taken into account. It was impossible to adjust for this.
[0008]
Accordingly, the present invention has been made to solve such a problem, and adjusts the optical axis direction of the headlamp while taking into account static and dynamic posture changes of the vehicle and changes in the occupant while the vehicle is stopped. It is an object of the present invention to provide a vehicle headlamp optical axis direction automatic adjustment device that can simplify the system configuration and achieve cost reduction.
[0009]
[Means for Solving the Problems]
The vehicle headlamp optical axis direction automatic adjustment device according to claim 1 is an absolute inclination angle detecting means comprising one inclinometer for detecting an absolute inclination angle θa which is inclination information with respect to the gravity direction of the vehicle, and the acceleration α of the vehicle. An estimated road surface inclination angle θRe, including an acceleration detection means for detecting a vehicle body, an estimated pitch angle θpe as a vehicle body inclination angle estimated from the absolute inclination angle θa and the acceleration α, and an error angle ± θerror corresponding to the inclination of the road surface itself. The estimated road surface inclination angle θRe estimated by the road surface inclination angle estimation means to be estimated and the road surface inclination angle estimation means when the vehicle is traveling on flat ground is set to zero, and the estimated road surface inclination angle θRe and the absolute inclination angle detection means are Based on the obtained difference between the absolute inclination angle θa and the control angle calculation means for calculating the control angle θact of the headlamp of the vehicle, and based on the control angle θact calculated by the control angle calculation means, Light that adjusts the optical axis direction of the lamp It comprises a direction adjusting means.
Therefore, the control angle calculation means uses the estimated road surface inclination angle θRe estimated by the road surface inclination angle estimation means from the absolute inclination angle θa by one absolute inclination angle detection means and the vehicle body inclination angle estimated from the acceleration α by the acceleration detection means. Based on the calculated control angle θact , the optical axis direction of the vehicle headlamp is adjusted by the optical axis direction adjusting means. For this reason, static and dynamic attitude changes of the vehicle are taken into consideration, the system configuration for adjusting the optical axis direction of the headlamp is simplified, and cost reduction is achieved.
[0010]
In the vehicle headlamp optical axis direction automatic adjustment device according to claim 2, if there is a change in the absolute inclination angle θa by the absolute inclination angle detecting means while the vehicle is stopped, the road surface inclination angle is assumed to be due to the occupant change by the road surface inclination angle estimating means. The estimated road surface inclination angle θRe estimated by the estimating means is corrected. Thereby, the passenger | crew change and load change during a stop are also considered, and the optical axis direction of a headlamp is adjusted normally.
[0011]
In the vehicle headlamp optical axis direction automatic adjustment device according to claim 3, the absolute inclination angle θa stored in the absolute inclination angle storage means immediately before the ignition switch of the vehicle is turned off, and the absolute inclination angle when the ignition switch is turned on the next time. The estimated road surface inclination angle θRe estimated by the road surface inclination angle estimation unit is corrected by assuming that the difference from the absolute inclination angle θa by the detection unit is due to occupant change. As a result, occupant changes and load changes while the ignition switch is off are taken into consideration, and the optical axis direction of the headlamp is adjusted normally.
[0012]
In the vehicle headlamp optical axis direction automatic adjustment device according to the fourth aspect, the abnormality determining means determines whether the vehicle is running or stopped based on the variation of the absolute inclination angle θa from the absolute inclination angle detecting means. If there is a difference between the two, it is determined that the system is abnormal. Thereby, it is possible to accurately know the occupant change while the vehicle is stopped.
[0013]
In the vehicular headlamp optical axis direction automatic adjustment device according to the fifth aspect, when the abnormality determination means determines that the system is abnormal, the control is stopped after returning the optical axis direction of the headlamp to the control position before the occurrence of the abnormality. The Thereby, inappropriate control of the optical axis direction of the headlamp when the system is abnormal is prevented.
[0014]
In the vehicle headlamp optical axis direction automatic adjustment device according to claim 6, the initial value of the absolute inclination angle θa is corrected after the absolute inclination angle detecting means is assembled to the vehicle or after a system abnormality occurs. . As a result, the absolute inclination angle θa from the absolute inclination angle detecting means after assembly of the absolute inclination angle detecting means or after the system abnormality becomes an appropriate value, and its reliability can be improved.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described based on examples.
[0016]
FIG. 1 is a schematic diagram showing an overall configuration of a vehicular headlamp optical axis direction automatic adjusting apparatus according to an embodiment of the present invention.
[0017]
In FIG. 1, the vehicle speed (wheel speed) V is measured by a wheel speed sensor 11 or the like that is disposed in a vehicle and used in a well-known ABS (Antilock Brake System), and is also measured by an inclinometer 12 disposed in the vehicle body. The absolute tilt angle θa, which is the tilt angle with respect to the direction of gravity, and other sensor signals (not shown) are input to an ECU (Electronic Control Unit) 20 mounted on the vehicle. The ECU 20, the wheel speed sensor 11 and the inclinometer 12 are shown outside the vehicle for convenience.
[0018]
The ECU 20 includes a CPU 21 as a central processing unit that executes various known arithmetic processes, a ROM 22 that stores control programs, a RAM 23 that stores various data, a B / U (backup) RAM 24, an input / output circuit 25, and a bus that connects them. It is configured as a logical operation circuit composed of lines 26 and the like.
[0019]
Then, as will be described later, the control angle θact is calculated by the CPU 21 in the ECU 20 based on the vehicle speed V signal from the wheel speed sensor 11 and the absolute inclination angle θa from the inclinometer 12, and the right and left headlights (headlights) of the vehicle The light is input to the actuator 35 on the 30 side, and the optical axis directions of the left and right headlights 30 are automatically adjusted.
[0020]
FIG. 2 is a cross-sectional view showing a main configuration of the headlight 30 shown in FIG.
[0021]
In FIG. 2, a headlight 30 mainly supports a lamp 31 and a reflector 32 for fixing the lamp 31, a support portion 33 that supports the reflector 32 so as to be swingable in the direction of an arc, and the reflector 32 and is movable. The other movable portion 34, and an actuator 35 including a step motor for driving the movable portion 34 in the front-rear arrow direction. The optical axis direction of the headlight 30 is initially set on the assumption that one driver is in the vehicle.
[0022]
Next, the flat ground (start acceleration) by the CPU 21 in the ECU 20 used in the vehicle headlamp optical axis direction automatic adjustment device according to an example of the embodiment of the present invention → slope (up / down: constant speed) → Calculation of control angle θact for driving actuator 35 that automatically adjusts the optical axis direction of headlight 30 with reference to the time chart of FIG. 3 showing transition states of various control amounts corresponding to flat ground (deceleration stop) Will be described.
[0023]
In general, since the spring constant of a suspension of a vehicle is linear in the normal range, it is known that there is a proportional relationship between acceleration and a change in pitch angle from when the vehicle is stopped. Therefore, as shown in FIG. 3, if it is a flat ground, the estimated pitch angle θpe based only on acceleration can be obtained by the following equation (1). Here, α is the acceleration by the differential (dV / dt) calculation of the vehicle speed V, K is the spring constant, and θp0 is the pitch angle when the vehicle is stopped.
[0024]
[Expression 1]
θpe = α ・ K + θp0 (1)
[0025]
On the other hand, the absolute inclination angle θa obtained from the inclinometer 12 always includes the ground pitch angle θpe with respect to the actual road surface and the inclination of the road surface itself. That is, the estimated road surface inclination angle θRe includes an error angle ± θ error as the inclination of the road surface itself. Therefore, the estimated road surface inclination angle θRe can be obtained by the following equation (2).
[0026]
[Expression 2]
θRe = θa−θpe (2)
[0027]
Here, when the vehicle actually travels on a hill, there is a change in the posture of the vehicle due to gravity, and a positive error angle θ error occurs on the uphill and a negative error angle −θerror occurs on the downhill. In order to correct this, after calculating the estimated road surface inclination angle θRe, it is necessary to estimate the error angle ± θerror from the estimated road surface inclination angle θRe and correct the error angle ± θerror .
[0028]
In this way, when running on a slope, the control angle θact is calculated by the following equation (3) from the difference between the estimated road surface inclination angle θRe and the absolute inclination angle θa. Based on this control angle θact, the actuator 35 is driven and the optical axis direction of the headlight 30 is automatically adjusted.
[0029]
[Equation 3]
θact = − (θa−θRe) (3)
[0030]
Further, when traveling on flat ground, that is, when the estimated road inclination angle θRe is substantially “0”, the absolute inclination angle θa as the output of the inclinometer 12 indicates the ground inclination angle. θact is calculated. Based on this control angle θact, the actuator 35 is driven and the optical axis direction of the headlight 30 is automatically adjusted.
[0031]
[Expression 4]
θact = −θa (4)
[0032]
Thus, the vehicular headlamp optical axis direction automatic adjustment device of the present embodiment includes an inclinometer 12 as one absolute inclination angle detecting means for detecting an absolute inclination angle θa that is inclination information with respect to the gravity direction of the vehicle, Acceleration detecting means achieved by the CPU 21 in the ECU 20 that detects the acceleration α by differentiating the vehicle speed V signal from the vehicle wheel speed sensor 11, and the vehicle body inclination angle estimated from the absolute inclination angle θa and the acceleration α. Based on the estimated road surface inclination angle θre obtained from the estimated road surface inclination angle θre obtained by the CPU 21 in the ECU 20 and the estimated road surface inclination angle θRe obtained from the road surface inclination angle estimation means. Based on the control angle calculation means achieved by the CPU 21 in the ECU 20 for calculating the control angle θact of the headlight (headlight) 30 and the control angle θact calculated by the control angle calculation means. CPU21 in ECU20 for adjusting an optical axis direction of the headlight 30, in which includes an optical axis direction adjusting means comprising an actuator 35 like.
[0033]
That is, the optical axis direction of the headlight 30 of the vehicle is adjusted based on the control angle θact calculated by the estimated road surface inclination angle θRe obtained from the absolute inclination angle θa and the estimated pitch angle θpe estimated from the acceleration α. For this reason, static and dynamic attitude changes of the vehicle are taken into consideration, the system configuration for adjusting the optical axis direction of the headlight 30 is simplified, and cost reduction can be achieved.
[0034]
Next, the flat ground (start acceleration) by the CPU 21 in the ECU 20 used in the vehicle headlamp optical axis direction automatic adjustment device according to an example of the embodiment of the present invention → slope (up / down: constant speed) → Actuator 35 for automatically adjusting the optical axis direction of the headlight 30 with reference to the time chart of FIG. 4 showing transition states of various control amounts and the like corresponding to the slope (deceleration stop on the way down and occupant change while stopping) The calculation of the control angle θact for driving will be described.
[0035]
Even when acceleration / deceleration occurs during running on a slope, the control angle θact is calculated in the same manner using the above equation (3). However, as shown in FIG. 4, when the occupant changes during the stop and the absolute inclination angle θa obtained from the inclinometer 12 changes, the following correction is required. That is, when the vehicle is stopped, the estimated pitch angle θpe does not change and only the absolute inclination angle θa changes.
[0036]
First, the case where there is no correction corresponding to the change Δθa in the absolute tilt angle will be described.
[0037]
A change ΔθRe of the estimated road surface inclination angle is obtained by the following equation (5) (shown by a broken line in FIG. 4). Here, Δθa is a change in the absolute inclination angle due to a change in the occupant while the vehicle is stopped, and Δθpe is a change in the estimated pitch angle, which can be regarded as “0”.
[0038]
[Equation 5]
ΔθRe = Δθa−Δθpe = Δθa (5)
[0039]
Therefore, the change Δθact of the control angle is obtained by the following equation (6).
[0040]
[Formula 6]
Δθact = − (Δθa−ΔθRe) = 0 (6)
[0041]
In other words, despite the change in the ground pitch angle θp due to a change in the occupant while the vehicle is stopped, the change in absolute inclination angle Δθa is “0”, so control is not performed, and an error occurs in the estimated road inclination angle θRe. It becomes. Therefore, when there is a change in the absolute inclination angle θa while the vehicle is stopped, it is necessary to make a correction corresponding to the change Δθa in the absolute inclination angle, assuming that the change Δθa in the absolute inclination angle is an occupant change. It is.
[0042]
Therefore, a case where there is a correction corresponding to the change Δθa in the absolute inclination angle will be described.
[0043]
When there is a change in the absolute inclination angle θa while the vehicle is stopped, it is assumed that the change Δθa in the absolute inclination angle is an occupant change, and as shown by the solid line in FIG. Correction is added to θpe.
[0044]
[Expression 7]
θpe = α · K + (θp0 + Δθa) (7)
[0045]
As a result, the estimated road surface inclination angle θRe does not change, and the change amount Δθact of the control angle is obtained by the following equation (8), and the optical axis direction of the headlight 30 is normally automatically adjusted.
[0046]
[Equation 8]
Δθact = − (Δθa−ΔθRe) = − Δθa (8)
[0047]
Incidentally, when the ECU 20 is not in an operating state at the time of IG-OFF (ignition switch-off) shown in FIG. 4, even if an occupant is changed while the vehicle is stopped, the change Δθa of the absolute inclination angle can be detected. Therefore, the correction as described above cannot be performed. That is, since the ECU 20 cannot recognize the change Δθa in the absolute inclination angle as a change in the occupant while the vehicle is stopped, the road inclination angle is not known. For this reason, even at the time of IG-OFF, the ECU 20 is directly connected to a battery power source (not shown) or a non-volatile memory such as an EEPROM (Electrical Erasable Programmable ROM) is mounted in the ECU 20, The absolute inclination angle θa0 immediately before IG-OFF is stored, and the change Δθa of the absolute inclination angle is obtained from the difference with the absolute inclination angle θa at the next IG-ON (ignition switch-on) time by the following equation (9). Then, the same correction as described above is applied to the estimated pitch angle θpe with the change Δθa of the absolute inclination angle as the occupant change while the vehicle is stopped.
[0048]
[Equation 9]
Δθa = θa−θa0 (9)
[0049]
As a result, the estimated road surface inclination angle θRe does not change, and the control angle change Δθact is obtained at the time of IG-ON after the occupant change time when the vehicle is stopped in the above equation (8). The direction is automatically adjusted normally.
[0050]
Thus, the vehicular headlamp optical axis direction automatic adjustment device of the present embodiment includes an inclinometer 12 as one absolute inclination angle detecting means for detecting an absolute inclination angle θa that is inclination information with respect to the gravity direction of the vehicle, Acceleration detecting means achieved by the CPU 21 in the ECU 20 that detects the acceleration α by differentiating the vehicle speed V signal from the vehicle wheel speed sensor 11, and the vehicle body inclination angle estimated from the absolute inclination angle θa and the acceleration α. Based on the estimated road surface inclination angle θre obtained from the estimated road surface inclination angle θre obtained by the CPU 21 in the ECU 20 and the estimated road surface inclination angle θRe obtained from the road surface inclination angle estimation means. Based on the control angle calculation means achieved by the CPU 21 in the ECU 20 for calculating the control angle θact of the headlight 30 and the control angle θact calculated by the control angle calculation means, CPU21 in ECU20 for adjusting an optical axis direction of the bets 30, in which includes the optical axis direction adjusting means comprising an actuator 35 like.
[0051]
Further, the road surface inclination angle estimation means achieved by the CPU 21 in the ECU 20 of the vehicle headlamp optical axis direction automatic adjustment device of this embodiment is based on changes in the occupant when there is a change in the absolute inclination angle θa while the vehicle is stopped. As an example, the estimated road surface inclination angle θRe is corrected. The vehicular headlamp optical axis direction automatic adjustment device of the present embodiment includes a nonvolatile memory (such as an EEPROM) as absolute inclination angle storage means for storing the absolute inclination angle θa0 immediately before IG-OFF in the vehicle, The road surface inclination angle estimation means achieved by the CPU 21 in the ECU 20 estimates the difference between the absolute inclination angle θa at the next IG-ON and the absolute inclination angle θa0 stored in the non-volatile memory as a occupant change. This corrects the road surface inclination angle θRe.
[0052]
That is, the optical axis direction of the headlight 30 of the vehicle is adjusted based on the control angle θact calculated by the estimated road surface inclination angle θRe obtained from the absolute inclination angle θa and the estimated pitch angle θpe estimated from the acceleration α. Here, when there is a change in the absolute inclination angle θa while the vehicle is stopped, the estimated road surface inclination angle θRe is corrected as a result of the occupant change. Specifically, the difference between the absolute inclination angle θa0 stored in the non-volatile memory immediately before the IG-OFF in the vehicle and the absolute inclination angle θa at the next IG-ON is caused by the occupant change. For this reason, static and dynamic attitude changes of the vehicle, occupant changes while the vehicle is stopped, etc. are taken into consideration, and the system configuration for adjusting the optical axis direction of the headlight 30 is simplified and the cost reduction is achieved. Can do.
[0053]
In the above embodiment, the estimated pitch angle θpe from the acceleration α is very important for estimating the estimated road surface inclination angle θRe. That is, if there is an abnormality in the vehicle speed V signal, it is determined that the vehicle is all stopped, and it is erroneously determined that all changes in pitch angle due to acceleration / deceleration or road surface inclination are due to changes in the occupant. Therefore, it is determined whether the vehicle is running or stopped based on the variation of the absolute inclination angle θa from the inclinometer 12, and if there is a discrepancy between this determination and the vehicle speed V signal, it is determined that the system is abnormal, and before the failure (abnormality) occurs. After returning the optical axis direction of the headlight 30 to the control position at, the control is stopped. Note that the determination of whether the vehicle is running or stopped is made based on, for example, fluctuations and variations in the absolute inclination angle θa from the inclinometer 12 within a few seconds. The control position before the occurrence of the failure is the initial control position of the headlight 30 in the optical axis direction .
[0054]
Such a vehicle headlamp optical axis direction automatic adjusting device determines whether the vehicle is running or stopped based on the absolute inclination angle θa detected by an inclinometer 12 as an absolute inclination angle detecting means, and a wheel speed sensor 11. The abnormality determination means achieved by CPU21 in ECU20 which determines a system abnormality by the difference with the vehicle speed V from is provided. When the optical axis direction adjusting means including the CPU 21, the actuator 35, etc. in the ECU 20 is determined as a system abnormality by the abnormality determining means achieved by the CPU 21 in the ECU 20, the headlight 30 is moved to the control position before the occurrence of the abnormality. The control is stopped after the direction of the optical axis is returned. The inclinometer 12 as the absolute inclination angle detecting means corrects the initial value of the absolute inclination angle θa after being assembled to the vehicle or after a system abnormality occurs.
[0055]
In addition, it is desirable that the inclinometer 12 in the above-described embodiment is accurately assembled with respect to the horizontal reference of the vehicle body. However, since an assembly error actually occurs, when the vehicle is horizontal at the time of factory shipment or the like. Work to correct the assembly error is required. In addition, if the current road surface inclination angle θR is once unknown due to an abnormality in the vehicle speed V signal or other system abnormality, the automatic adjustment of the optical axis direction of the headlight 30 cannot be performed thereafter, so the vehicle posture is once changed. Correction in the horizontal state is required. This correction value is stored in an EEPROM, which is a non-volatile memory.
[0056]
The correction value is written to the EEPROM or the like in the following procedure.
[0057]
A reset button (not shown) is installed in the driver's seat of the vehicle, and after stopping at the vehicle horizontal position, the correction value may be started to be written to the EEPROM by pressing the reset button. If possible, it can be considered that the vehicle is improperly corrected in a non-horizontal state or during traveling. Accordingly, as a write start condition, the headlight 30 is turned “OFF (lights off) within a predetermined time after the vehicle speed V is“ 0 ”, the absolute inclination angle θa from the inclinometer 12 is within a predetermined range, and the reset signal is“ ON ”. ) ”→“ ON (lit) ”, for example, a warning light (Warning Lump) blinks during writing to notify the worker that writing is in progress, and the warning light turns off when writing is completed normally I will let you.
[0058]
The inclinometer 12 in the above embodiment may be arranged on the printed circuit board of the ECU 20 as a configuration like a semiconductor sensor. Further, instead of the wheel speed sensor 11, a known semiconductor acceleration sensor may be used and disposed on the printed circuit board of the ECU 20 together with the inclinometer 12. This makes it possible to construct a closed loop control system that does not require an external input signal.
[Brief description of the drawings]
FIG. 1 is a schematic diagram showing the overall configuration of a vehicular headlamp optical axis direction automatic adjusting apparatus according to an embodiment of the present invention.
FIG. 2 is a cross-sectional view showing a main configuration of the headlight 30 of FIG.
FIG. 3 corresponds to a vehicle acceleration / deceleration situation and a road surface change by a CPU in an ECU used in the vehicle headlamp optical axis direction automatic adjustment device according to one embodiment of the present invention. It is a time chart which shows transition states, such as various control amounts.
FIG. 4 is a view showing acceleration / deceleration status of a vehicle, a change in road surface, and a stop by a CPU 21 in an ECU 20 used in a vehicle headlamp optical axis direction automatic adjusting device according to an embodiment of the present invention. It is a time chart which shows transition states, such as various control amounts corresponding to a passenger | crew change.
[Explanation of symbols]
12 Inclinometer 20 ECU (Electronic Control Unit)
30 Headlight (headlight)
35 Actuator

Claims (6)

Absolute inclination angle detection means comprising one inclinometer for detecting an absolute inclination angle (θa) which is inclination information with respect to the direction of gravity of the vehicle;
Acceleration detecting means for detecting the acceleration (α) of the vehicle;
Estimated road surface inclination angle (θRe) including an estimated pitch angle (θpe) as a vehicle body inclination angle estimated from the absolute inclination angle (θa) and the acceleration (α ) and an error angle (± θerror) corresponding to the inclination of the road surface itself. ) For estimating the road surface inclination angle,
The estimated road surface inclination angle (θRe) estimated by the road surface inclination angle estimation means when the vehicle is traveling on flat ground is set to zero, and the estimated road surface inclination angle (θRe) and the absolute inclination angle obtained by the absolute inclination angle detection means A control angle calculation means for calculating a control angle (θact) of the headlight of the vehicle based on a difference from (θa) ;
The vehicle headlamp optical axis direction includes an optical axis direction adjusting unit that adjusts the optical axis direction of the headlamp based on the control angle (θact) calculated by the control angle calculation unit. Automatic adjustment device. The road surface inclination angle estimation means corrects the estimated value of the estimated road surface inclination angle (θRe) as a result of occupant change when there is a change in the absolute inclination angle (θa) while the vehicle is stopped. The vehicle headlamp optical axis direction automatic adjustment device according to claim 1. Further, the vehicle includes absolute inclination angle storage means for storing the absolute inclination angle (θa) immediately before the ignition switch is turned off in the vehicle, and the road surface inclination angle estimation means is configured to turn on the absolute inclination when the ignition switch is turned on next time. the absolute inclination angle stored in the angle between (.theta.a) the absolute inclination angle storing means the difference between (.theta.a) as by the occupant changes, and characterized in that for correcting the estimated value of the estimated road surface inclination angle ([theta] re) The vehicle headlamp optical axis direction automatic adjustment device according to claim 1 or 2. Furthermore, it comprises an abnormality determining means for determining whether the vehicle is running or stopped based on the absolute inclination angle (θa) detected by the absolute inclination angle detecting means, and determining a system abnormality based on a difference from the vehicle speed. The vehicle headlamp optical axis direction automatic adjustment device according to any one of claims 1 to 3, wherein The optical axis direction adjusting means stops the control after returning the optical axis direction of the headlamp to the control position before the occurrence of abnormality when the abnormality determining means determines that the system is abnormal. Item 5. The vehicle headlamp optical axis direction automatic adjustment device according to Item 4. The absolute inclination angle detecting means corrects an initial value of the absolute inclination angle (θa) after being assembled to the vehicle or after a system abnormality occurs. The vehicle headlamp optical axis direction automatic adjustment device according to any one of 5.

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