JP4140656B2 - Automatic headlamp optical axis adjustment device for vehicles - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To automatically adjust the optical axis direction of a headlight of a vehicle by correcting the displacement of the vehicle by acceleration/deceleration or turning according to the output of a vehicle height sensor. <P>SOLUTION: A measured rear height value (the displaced amount of the vehicle height on the rear wheel side) is input from the height sensor 11 mounted at the rear of the vehicle into an ECU 20. Based on the measured rear height value and the travelling state of the vehicle by a vehicle speed sensor 12, the calculated front height value (the displaced amount of the vehicle height on the front wheel side) is estimated, and the pitch angle of the vehicle is calculated. Since an error occurs in the acceleration/deceleration and the turning of the vehicle, the calculated front height value is updated. Even if the vehicle is before the completion of one trip, the error is canceled by the ECU 20, and an actuator 35 is driven to properly adjust the optical axis direction of a headlight 30. <P>COPYRIGHT: (C)2008,JPO&amp;INPIT

Description

  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.

  Conventionally, in a vehicle headlamp, when the optical axis direction of the headlamp is upward due to the inclination of the vehicle body, glare is given to an oncoming vehicle or the like, and when the optical axis direction is downward, the driver's distance visibility decreases. Therefore, there is a demand for keeping the optical axis direction of the headlamp constant.

  By the way, in the vehicle headlamp optical axis direction automatic adjustment device, in order to obtain the inclination angle in the front-rear direction of the vehicle, it is disposed between the front and rear axles of the vehicle and the vehicle body, and the relative displacement amount (displacement of the vehicle height) therebetween. A vehicle height sensor that detects the amount) is used. Here, since the front wheel (front) side is a steered wheel and the installation space is limited, the vehicle height sensor is attached only to the left and right sides of the rear wheel (rear), and the rear height when the vehicle is stopped from this vehicle height sensor. There is known a technique in which a front height value is estimated based on a value to calculate an inclination angle.

  Then, when the vehicle is stopped on the curb or the like, a rear height value different from the value on the flat road is detected, and in the subsequent one trip (traveling section from the stop of the vehicle to the stop) There is a problem that a calculation error occurs in the tilt angle in the front-rear direction of the vehicle, and the optical axis direction of the headlamp is shifted. Also, during the turn, the rear height value fluctuates despite the fact that the vehicle's front / rear tilt angle does not appear due to rolling, which is a rotational movement around the front / rear axis of the vehicle. There was also a problem that a calculation error occurred in the tilt angle, and as a result, the optical axis direction of the headlamps shifted.

  Accordingly, the present invention has been made to solve such a problem, and an object thereof is to provide an inexpensive vehicle headlamp optical axis direction automatic adjustment device with a simple system, and in particular, the optical axis direction of a vehicle headlamp. When the vehicle is automatically adjusted based on the output from one vehicle height sensor, the headlamp's optical axis direction shift is appropriate when the vehicle is on a curb or the like while the vehicle is stopped It is an object of the present invention to provide a vehicular headlamp optical axis direction automatic adjustment device that can be corrected to the above.

According to the vehicular headlamp optical axis direction automatic adjusting apparatus of claim 1, when it is determined that the vehicle is not in a stable running state, the front height calculation in which the inclination angle of the headlamp in the optical axis direction is corrected by the correcting means. Since the adjustment is performed based on the value, the effect of appropriately adjusting the deviation of the headlamp in the optical axis direction can be obtained. Further, the rear height measurement value information and the front height calculation value are adopted as a reference value when the vehicle is stopped, and if the comparison result between the reference value and the value in the stable running state is a predetermined value or more, Since the value in the stable running state is replaced with the reference value, an effect that a highly reliable system can be constructed is obtained.

  Hereinafter, embodiments of the present invention will be described based on examples.

  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.

  In FIG. 1, a height sensor (vehicle height sensor) 11 is attached to an axle on the driver's seat or passenger's seat on the rear side of the vehicle. From this height sensor 11, the rear height value as the relative displacement amount (vehicle height displacement amount) between the rear wheel axle and the vehicle body (the displacement amount of the rear wheel vehicle height: hereinafter also referred to as “rear height measurement value”). HR, vehicle speed V from well-known vehicle speed sensor 12 arranged on the vehicle side, right wheel speed sensor 13 from right wheel speed VWR, left wheel speed sensor 14 from left wheel speed VWL, and other sensors (not shown) Various sensor signals and the like are input to an ECU (Electronic Control Unit) 20 mounted on the vehicle. The ECU 20 is shown outside the vehicle for convenience.

  The ECU 20 is a logic composed of a CPU 21 as a known central processing unit, a ROM 22 storing a control program, a RAM 23 storing various data, a B / U (backup) RAM 24, an input / output circuit 25, a bus line 26 connecting them, and the like. It is configured as an arithmetic circuit.

  An output signal from the ECU 20 is input to the actuator 35 on the headlight (headlight) 30 side of the vehicle, and the optical axis direction of the headlight 30 is adjusted as will be described later. Note that various sensor signals from the vehicle speed sensor 12, the right wheel speed sensor 13, the left wheel speed sensor 14, etc. indicate whether the vehicle is in a stopped state, an acceleration / deceleration state, a constant speed running (stable running) state, or the like. It is used for determination and turning determination as to whether the vehicle is turning.

  FIG. 2 is a cross-sectional view showing a main configuration of the headlight 30 shown in FIG.

  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.

  Next, to the curb etc. when the vehicle is stopped by the adjustment control in the optical axis direction of the headlight (headlight) 30 by the vehicle headlamp optical axis direction automatic adjusting device according to one example of the embodiment of the present invention. The basic concept for executing the ride-on determination will be described with reference to FIGS. 3 and 4.

  FIG. 3 shows changes in the vehicle speed [km / h] when the vehicle is on the curbstone or the like from the stoppage state to acceleration → constant speed traveling → deceleration → flat ground stop state before application of the adjustment control according to the present embodiment. It is a time chart which shows the transition state of each displacement amount [mm] of the rear height measurement value by the corresponding height sensor 11, the front height calculation value based on it, and the front height measurement value for comparison.

  In FIG. 3, in the initial stop state of the vehicle, the rear height is detected as a state in which the rear suspension is contracted due to a stop on the curb or the like. Thereafter, since the front height calculation value is calculated based on the displacement amount of the rear height measurement value, the front height calculation value includes an error, and there is a large deviation from the actual front height measurement value. For this reason, an error also occurs in the calculation of the pitch angle of the vehicle body, and if the optical axis direction of the headlight 30 is adjusted based on this pitch angle, it will deviate from an appropriate angle, and glare will be given to oncoming vehicles and the like. .

  FIG. 4 is a time chart showing a transition state of the rear height measurement value by the height sensor 11 corresponding to a change in the vehicle speed [km / h] when the vehicle goes from a flat stoppage state to acceleration → constant speed running state.

  In FIG. 4, the displacement of the rear height measurement value changes corresponding to the change in the vehicle speed [km / h]. That is, while the vehicle is running, the rear height measurement value varies finely due to the unevenness of the road surface. It can be seen that the average amount of displacement of the measured rear height during the stable running is substantially equal to the amount of displacement of the measured rear height when the vehicle is stationary. Therefore, if the rear height measurement value during constant speed running is averaged and a deviation greater than a predetermined threshold is found by comparison with the rear height measurement value when the vehicle is stopped, the averaged rear height during constant speed running is determined. By calculating the front height calculation value in place of the measurement value, the error described in FIG. 3 can be corrected. At this time, it is important that the vehicle is traveling at a constant speed, and during acceleration / deceleration, traveling on rough roads, turning, etc., the rear height measurement value is not equivalent to that of a flat ground stop. Is done. In addition, as a determination when the error correction is performed, the rear height measurement value is compared between when the vehicle is stationary and when traveling at a constant speed. You may determine based on an adjustment control position, a pitch angle, etc.

  Next, processing to cope with climbing on a curb or the like while the vehicle is stopped in 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. The procedure will be described based on the flowchart of FIG. This control routine is repeatedly executed by the CPU 21 every predetermined time.

In FIG. 5, first, in step S101, various sensor signals such as the vehicle speed V from the vehicle speed sensor 12 and the rear height value (rear height measurement value) HR from the height sensor 11 are read. At this time, if the vehicle is stopped, the rear height value HR becomes the rear height value (rear height measurement value) HR0 when the vehicle is stopped. Next, the process proceeds to step S102, and it is determined whether the vehicle speed V read in step S101 is less than 2 [km / h]. When the determination condition of step S102 is satisfied, that is, when the vehicle speed V is low as less than 2 [km / h], the vehicle is stopped and the process proceeds to step S103, and the pitch angle θ0 when the vehicle is stopped is measured for the rear height when the vehicle is stopped. Based on the value HR0, the following equation (1) is used. Here, HF0 is a front height calculation value when the vehicle is stopped, a and b are constants set in advance by spring constants or the like of the suspension specifications of the front and rear wheels, and L is a distance between the front and rear wheels.
(Equation 1)
HF0 = a ・ HR0 + b
θ0 = tan ⁻¹ {(HF0−HR0) / L} (1)
Next, the process proceeds to step S104, and a filtering process such as a moving average is performed on the pitch angle θ0 calculated in step S103, the front height calculated value HF0 during stopping, and the rear height measured value HR0. Next, the process proceeds to step S105, and the target optical axis direction adjustment angle θT (≈−θ0) that does not give glare to the oncoming vehicle is calculated with respect to the pitch angle θ0 when the vehicle is filtered in step S104. .

On the other hand, when the determination condition of step S102 is not satisfied, that is, when the vehicle speed V is high at 2 [km / h] or higher, the process proceeds to step S106 as the vehicle is traveling, and the pitch angle θ1 during traveling of the vehicle is Is calculated by the following equation (2) based on the measured rear height HR and the measured rear height HR0 when the vehicle is stopped. Here, ΔHR is the amount of displacement of the measured rear height, α is a correction factor of about 0.5 to 2 set in advance by the spring constant of the suspension specifications of the front and rear wheels, ΔHF is the amount of displacement of the calculated front height, and HF is The front height calculation value, HF0, is the front height calculation value when the vehicle is stopped.
(Equation 2)
ΔHR = HR-HR0
ΔHF = -α · ΔHR
HF = HF0 + ΔHF
θ1 = tan ⁻¹ {(HF−HR) / L} (2)
Next, the process proceeds to step S107, and it is determined whether or not | dV / dt |, which is an absolute value of acceleration obtained by differentiating the vehicle speed V, exceeds 1 [m / s ² ]. When the determination condition in step S107 is satisfied, that is, when | dV / dt |, which is the absolute value of acceleration, exceeds 1 [m / s ² ], the process proceeds to step S108 as accelerating / decelerating, and is calculated in step S106. A predetermined filtering process is executed for the pitch angle θ1. Next, the process proceeds to step S109, and a target optical axis direction adjustment angle θT (≈−θ1) that does not give glare to the oncoming vehicle with respect to the pitch angle θ1 during acceleration / deceleration filtered in step S108 is calculated. The

On the other hand, when the determination condition of step S107 is not satisfied, that is, when | dV / dt |, which is the absolute value of acceleration, is small as less than 1 [m / s ² ], it is determined that the vehicle is traveling at a constant speed, and the process proceeds to step S110. A predetermined filtering process is performed on the pitch angle θ1, the front height calculation value HF, and the rear height measurement value HR calculated in step S106. Next, the process proceeds to step S111, where it is determined whether or not the absolute value of the deviation between the pitch angle θ0 when the vehicle is stopped and the pitch angle θ1 when the vehicle is traveling at a constant speed exceeds 0.1 [°]. If the determination condition of step S111 is not satisfied, that is, if | θ0−θ1 | is as small as 0.1 [°] or less, it is determined that there is no need to consider the current pitch angle θ1, and the process proceeds to step S105. A target optical axis direction adjustment angle θT (≈−θ0) that does not give glare to the oncoming vehicle is calculated with respect to the pitch angle θ0 when the vehicle is stopped after filtering.

  On the other hand, when the determination condition of step S111 is satisfied, that is, when | θ0−θ1 | exceeds 0.1 [°], the vehicle is riding on a curb or the like while the vehicle is stopped, and the pitch angle θ0 at that time is inconvenient. That is, there is an abnormality in the reference angle when the vehicle is stopped, the process proceeds to step S112, and as a curb climbing cancellation process at this time, that is, the rear height measurement value HR and the front height calculation value HF during constant speed traveling are calculated. After determining the rear height measurement value HR0 and the front height calculation value HF0 when the vehicle is stopped, the process proceeds to step S113, and the pitch angle θ0 during the constant speed traveling of the vehicle is calculated and the pitch angle during the stop is calculated, as in the above equation (1). θ0 is updated. Next, the process proceeds to step S114, and the target optical axis direction adjustment angle θT (≈−θ0) that does not give glare to the oncoming vehicle is calculated with respect to the pitch angle θ0 during the constant speed calculation calculated in step S113. The

  After the processing of step S105, step S109, or step S114, the process proceeds to step S115, the actuator 35 is driven based on the calculated target optical axis direction adjustment angle θT, and this routine ends. The control speed setting for the actuator 35 is omitted. For this reason, if the vehicle is riding on a curb or the like while the vehicle is stopped and the pitch angle θ0 is inconvenient at that time, it is determined that the vehicle is traveling at a constant speed without waiting until the end of one trip. By executing the canceling process and updating the pitch angle θ0, the optical axis direction of the headlight 30 is adjusted appropriately thereafter.

  FIG. 6 shows a rear height measurement value by the height sensor 11 corresponding to a change in the vehicle speed [km / h] when correction for the error described in FIG. 3 is executed based on the flowchart of FIG. It is a time chart which shows the transition state of the displacement amount [mm] of the front height measurement value for a comparison.

  In FIG. 6, conditions such as vehicle speed and road surface are the same as in FIG. 3, and after the constant speed traveling determination is executed, the front height calculation value follows the front height measurement value almost at the same level. It can be seen that the error of the displacement amount due to climbing on the curb or the like while the vehicle is stopped is cancelled.

  That is, as shown in FIG. 7 as no correction, when there is an error in the amount of displacement due to climbing on a curb or the like while the vehicle is stopped, a deviation occurs in the optical axis direction adjustment amount [°] of the vehicle headlight 30. The optical axis direction is upward. On the other hand, in response to a change in the vehicle speed [km / h], the vehicle is in a constant speed running state, satisfying the above-described determination conditions, and an error in the amount of displacement due to climbing on a curb or the like while the vehicle is stopped is cancelled. Then, as shown in FIG. 7 that there is a correction, there is no shift in the optical axis direction adjustment amount [°] of the headlight 30 of the vehicle, and the optical axis direction is almost returned to the initial position.

  Thus, the vehicle headlamp optical axis direction automatic adjustment device of the present embodiment is arranged at the rear of the vehicle, and is output from the height sensor 11 as one vehicle height sensor that detects the displacement amount of the vehicle height. Based on the measured rear height HR0 when stopped or the measured rear height HR, the pitch angle θ0 when stopped corresponding to the inclination angle of the headlight (headlight) 30 of the vehicle with respect to the horizontal plane in the optical axis direction or during traveling The inclination angle calculating means achieved by the CPU 21 in the ECU 20 for calculating the pitch angle θ1, and the vehicle speed V and its vehicle speed as the vehicle running state during stopping, running, acceleration / deceleration, and constant speed running (stable running). A traveling state determination means achieved by the CPU 21 in the ECU 20 that makes a determination based on the magnitude of | dV / dt | that is the absolute value of the acceleration obtained by differentiating V; and the traveling state determination means Every time it is determined that the vehicle is running at a constant speed (stable running) and the pitch angle θ0 corresponding to the reference angle is abnormal, the inclination of the vehicle while the vehicle is stopped is determined based on the output from the height sensor 11 at that time. A reference angle update means that is achieved by the CPU 21 in the ECU 20 that updates the pitch angle θ0 corresponding to the reference angle of the angle, and an inclination angle calculation means that is based on the pitch angle θ0 corresponding to the reference angle by the reference angle update means. The optical axis direction adjusting means achieved by the CPU 21 in the ECU 20 for correcting the pitch angle θ1 corresponding to the calculated inclination angle during traveling and adjusting the optical axis direction of the headlight 30 is provided.

  Accordingly, the CPU 21 in the ECU 20 that achieves the inclination angle calculating means is a horizontal plane in the optical axis direction of the headlight 30 based on the measured rear height HR0 during stopping or the measured rear height HR that is output from one height sensor 11. The pitch angle θ0 during stopping or the pitch angle θ1 during traveling corresponding to the inclination angle with respect to is calculated, and the vehicle traveling state determined by the CPU 21 in the ECU 20 that achieves the traveling state determining means is the constant speed traveling state, When the pitch angle .theta.0 corresponding to the reference angle is abnormal, the CPU 21 in the ECU 20 that achieves the reference angle updating means updates the pitch angle .theta.0 when the vehicle is stopped based on the measured rear height HR. The pitch angle .theta.0 is updated to this pitch angle .theta.0. The CPU 21 in the ECU 20 that achieves the optical axis direction adjusting means based on the The pitch angle θ1 is corrected and the optical axis direction of the headlight 30 is adjusted. As a result, even if the vehicle is on a curb or the like while the vehicle is stopped and the optical axis direction of the headlight 30 is deviated, the pitch angle θ0 during the stop is updated when the vehicle enters a constant speed state before the end of one trip. Since the pitch angle θ1 during traveling is corrected, the deviation of the headlight 30 in the optical axis direction is adjusted appropriately.

  Next, processing to cope with climbing on a curb or the like while the vehicle is stopped in 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. A description will be given based on the flowchart of FIG. This control routine is repeatedly executed by the CPU 21 every predetermined time.

  In FIG. 8, first, in step S201, various sensor signals such as the vehicle speed V from the vehicle speed sensor 12 and the rear height value (rear height measured value) HR from the height sensor 11 are read. At this time, if the vehicle is stopped, the rear height value HR becomes the rear height value (rear height measurement value) HR0 when the vehicle is stopped. Next, the process proceeds to step S202, and it is determined whether the vehicle speed V read in step S201 is less than 2 [km / h]. When the determination condition of step S202 is satisfied, that is, when the vehicle speed V is low as less than 2 [km / h], it is determined that the vehicle is stopped and the process proceeds to step S203, and the pitch angle θ0 when the vehicle is stopped is measured for the rear height when the vehicle is stopped. It is calculated by the above formula (1) based on the value HR0.

  Next, the process proceeds to step S204, and a filtering process such as moving average is performed on the pitch angle θ0 calculated in step S203, the front height calculated value HF0 and the rear height measured value HR0 when the vehicle is stopped. Next, the process proceeds to step S205, and the target optical axis direction adjustment angle θT (≈−θ0) that does not give glare to the oncoming vehicle is calculated with respect to the pitch angle θ0 when the vehicle is filtered in step S204. .

  On the other hand, when the determination condition of step S202 is not satisfied, that is, when the vehicle speed V is high at 2 [km / h] or more, it is determined that the vehicle is traveling, the process proceeds to step S206, and the pitch angle θ1 during traveling of the vehicle is Is calculated by the above equation (2) based on the measured rear height HR and the measured rear height HR0 when the vehicle is stopped.

Next, the process proceeds to step S207, where it is determined whether or not | dV / dt |, which is the absolute value of the acceleration obtained by differentiating the vehicle speed V, exceeds 1 [m / s ² ]. When the determination condition of step S207 is satisfied, that is, when | dV / dt |, which is the absolute value of acceleration, exceeds 1 [m / s ² ], it is determined that acceleration / deceleration is in progress, and the process proceeds to step S208 and is calculated in step S206. A predetermined filtering process is executed for the pitch angle θ1. Next, the process proceeds to step S209, and the target optical axis direction adjustment angle θT (≈−θ1) that does not give glare to the oncoming vehicle is calculated with respect to the pitch angle θ1 during acceleration / deceleration filtered in step S208. The

On the other hand, if the determination condition in step S207 is not satisfied, that is, if the absolute value of | dV / dt | is smaller than 1 [m / s ² ], it is determined that the vehicle is traveling at a constant speed and the process proceeds to step S203 described above. Then, the same processing is executed.

  After the process of step S205 or step S209, the process proceeds to step S210, the actuator 35 is driven based on the calculated target optical axis direction adjustment angle θT, and this routine ends. The control speed setting for the actuator 35 is omitted. For this reason, if the vehicle is riding on a curb or the like while the vehicle is stopped and the pitch angle θ0 is inconvenient at that time, it is determined that the vehicle is traveling at a constant speed without waiting until the end of one trip. By executing the canceling process and updating the pitch angle θ0, the optical axis direction of the headlight 30 is adjusted appropriately thereafter.

  Thus, the vehicle headlamp optical axis direction automatic adjustment device of the present embodiment is arranged at the rear of the vehicle, and is output from the height sensor 11 as one vehicle height sensor that detects the displacement amount of the vehicle height. Based on the measured rear height HR0 when stopped or the measured rear height HR, the pitch angle θ0 when stopped corresponding to the inclination angle of the headlight (headlight) 30 of the vehicle with respect to the horizontal plane in the optical axis direction or during traveling The inclination angle calculating means achieved by the CPU 21 in the ECU 20 for calculating the pitch angle θ1, and the vehicle speed V and its vehicle speed as the vehicle running state during stopping, running, acceleration / deceleration, and constant speed running (stable running). A traveling state determination means achieved by the CPU 21 in the ECU 20 that makes a determination based on the magnitude of | dV / dt | that is the absolute value of the acceleration obtained by differentiating V; and the traveling state determination means Every time it is determined that the vehicle is in a constant speed running (stable running) state, the pitch angle θ0 corresponding to the reference angle of the tilt angle when the vehicle is stopped is updated based on the output from the height sensor 11 at that time. The reference angle update means achieved by the CPU 21 in the ECU 20 and the pitch angle corresponding to the inclination angle during traveling calculated by the inclination angle calculation means based on the pitch angle θ0 corresponding to the reference angle by the reference angle update means The optical axis direction adjusting means achieved by the CPU 21 in the ECU 20 that corrects θ1 and adjusts the optical axis direction of the headlight 30 is provided.

  Accordingly, the CPU 21 in the ECU 20 that achieves the inclination angle calculating means is a horizontal plane in the optical axis direction of the headlight 30 based on the measured rear height HR0 during stopping or the measured rear height HR that is output from one height sensor 11. When the vehicle is in a constant speed traveling state, the pitch angle θ0 during stopping or the pitch angle θ1 during traveling corresponding to the inclination angle with respect to is calculated and the traveling state of the vehicle determined by the CPU 21 in the ECU 20 that achieves the traveling state determination means is calculated. The pitch angle θ0 when the vehicle is stopped is updated based on the measured rear height HR by the CPU 21 in the ECU 20 that achieves the reference angle updating means, and the CPU 21 in the ECU 20 that achieves the optical axis direction adjusting means based on the pitch angle θ0. The pitch angle θ1 during traveling is corrected, and the optical axis direction of the headlight 30 is corrected. Is adjusted. As a result, regardless of whether or not the headlight 30 of the vehicle is displaced in the optical axis direction, once the vehicle enters the constant speed running state before the end of one trip, the pitch angle θ0 during the stop is updated and the pitch angle during the running is updated. Since θ0 is corrected, even if a deviation in the optical axis direction of the headlight 30 occurs at this time, the headlight 30 is appropriately adjusted.

  Next, as a modified example of the adjustment control of the headlight (headlight) 30 in the optical axis direction by the vehicle headlamp optical axis direction automatic adjusting device according to an example of the embodiment of the present invention, With reference to FIG. 9, a basic concept for executing vehicle turning determination in addition to determination to ride on a curb or the like when the vehicle is stopped will be described.

  FIG. 9 shows the rear height measurement by the height sensor 11 corresponding to the change in the vehicle speed [km / h] when the vehicle is stopped, accelerated, turned (middle acceleration), and decelerated before the adjustment control according to the present modification is applied. It is a time chart which shows the transition state of displacement amount [mm] of a value, a front height calculation value based on it, and a front height measurement value for comparison.

  In FIG. 9, when the vehicle is turning, the calculated front height begins to deviate from the measured front height. Here, during acceleration / deceleration or constant speed traveling during straight traveling of the vehicle, the front height calculation value and the pitch angle are accurately calculated based on the measured rear height. However, when the vehicle is turning, the rear height value fluctuates due to rolling, which is a rotational motion around the longitudinal axis of the vehicle, even though the vehicle is traveling at a constant speed and there is no tilt angle in the longitudinal direction. Then, a calculation error occurs in the tilt angle in the front-rear direction of the vehicle until the vehicle finishes turning, and as a result, the optical axis direction of the headlight 30 is shifted. This is because, for example, the height sensor 11 is mounted on the left side of the rear wheel, and when the vehicle is turning right, the rear suspension is lowered and the rear height measurement value is displaced to the (−) side. By calculating the calculated value. However, while the vehicle is turning, the actual front height measurement value and the rear height measurement value vary depending on the acceleration / deceleration state, but as shown in FIG. Therefore, for example, if there is a deviation greater than or equal to a predetermined threshold in the left and right wheel speeds, it is possible to eliminate the error by correcting the front height calculation value based on the rear height measurement value, assuming that the vehicle is turning. .

  Next, in addition to riding on the curb or the like while the vehicle is stopped in the CPU 21 in the ECU 20 used in the vehicle headlamp optical axis direction automatic adjustment device according to one example of the embodiment of the present invention, the vehicle A description will be given based on the flowchart of FIG. This control routine is repeatedly executed by the CPU 21 every predetermined time.

  In FIG. 10, first, in step S301, various sensor signals such as the vehicle speed V from the vehicle speed sensor 12, the rear height value (rear height measurement value) HR, the right wheel speed VWR, the left wheel speed VWL from the height sensor 11 are read. . If the vehicle is stopped at this time, the rear height value HR becomes the rear height value (rear height measured value) HR0 when the vehicle is stopped. Next, the process proceeds to step S302, and it is determined whether the vehicle speed V read in step S301 is less than 2 [km / h]. When the determination condition of step S302 is satisfied, that is, when the vehicle speed V is low and less than 2 [km / h], it is determined that the vehicle is stopped, and the process proceeds to step S303, and the pitch angle θ0 when the vehicle is stopped is the rear height measurement when the vehicle is stopped. It is calculated by the above formula (1) based on the value HR0.

  Next, the process proceeds to step S304, and a filtering process such as moving average is performed on the pitch angle θ0 calculated in step S303, the front height calculated value HF0 and the rear height measured value HR0 when the vehicle is stopped. Next, the process proceeds to step S305, and the target optical axis direction adjustment angle θT (≈−θ0) that does not give glare to the oncoming vehicle is calculated with respect to the pitch angle θ0 during the stop filtered in step S304. .

  On the other hand, if the determination condition of step S302 is not satisfied, that is, if the vehicle speed V is high at 2 [km / h] or more, the vehicle is traveling and the process proceeds to step S306, and the right wheel speed VWR read in step S301. It is determined whether the absolute value of the deviation between the left wheel speed VWL and the left wheel speed VWL exceeds 1.5 [km / h]. If the determination condition of step S306 is not satisfied, that is, if | VWR-VWL | is as small as 1.5 [km / h] or less, the process proceeds to step S307 assuming that the vehicle is traveling straight, and the pitch angle θ1 when the vehicle is traveling straight ahead is determined. Is calculated by the above equation (2) based on the rear height measurement value HR and the stopped rear height measurement value HR0.

On the other hand, when the determination condition of step S306 is satisfied, that is, when | VWR−VWL | exceeds 1.5 [km / h], the process proceeds to step S308, assuming that the vehicle is turning, and the pitch angle θ1 during traveling turning of the vehicle is determined. Is calculated by the following equation (3) based on the rear height measurement value HR at this time and the rear height measurement value HR0 when the vehicle is stopped. Here, β is a correction variable of about ± (0.5 to 2) depending on the acceleration / deceleration state of the vehicle, the left / right turning state, the increase / decrease of passengers and luggage, and the suspension specification.
(Equation 3)
ΔHR = HR-HR0
ΔHF = β · ΔHR
HF = HF0 + ΔHF
θ1 = tan ⁻¹ {(HF−HR) / L} (3)
After calculating the pitch angle θ1 in step S307 or step S308, the process proceeds to step S309, where it is determined whether | dV / dt |, which is the absolute value of the acceleration obtained by differentiating the vehicle speed V, exceeds 1 [m / s ² ]. The When the determination condition in step S309 is satisfied, that is, when | dV / dt |, which is the absolute value of acceleration, is greater than 1 [m / s ² ], it is determined that acceleration / deceleration is being performed and the process proceeds to step S310, and step S307 or step S308 is performed. A predetermined filtering process is performed on the pitch angle θ1 calculated in step (1). Next, the process proceeds to step S311, and the target optical axis direction adjustment angle θT (≈−θ1) that does not give glare to the oncoming vehicle is calculated with respect to the pitch angle θ1 during acceleration / deceleration filtered in step S310. The

On the other hand, if the determination condition in step S309 is not satisfied, that is, if | dV / dt |, which is the absolute value of acceleration, is smaller than 1 [m / s ² ], it is determined that the vehicle is traveling at a constant speed, and the process proceeds to step S312. A predetermined filtering process is performed on the pitch angle θ1, the front height calculation value HF, and the rear height measurement value HR calculated in step S307 or step S308. Next, the process proceeds to step S313, and it is determined whether or not the absolute value of the deviation between the pitch angle θ0 during stopping and the pitch angle θ1 during constant speed traveling exceeds 0.1 [°]. If the determination condition of step S313 is not satisfied, that is, if | θ0−θ1 | is as small as 0.1 [°] or less, it is determined that there is no need to consider the current pitch angle θ1, and the process proceeds to step S305. A target optical axis direction adjustment angle θT (≈−θ0) that does not give glare to the oncoming vehicle is calculated with respect to the pitch angle θ0 when the vehicle is stopped after filtering.

  On the other hand, when the determination condition of step S313 is satisfied, that is, when | θ0−θ1 | exceeds 0.1 [°], the vehicle is riding on a curb or the like while the vehicle is stopped, which is inconvenient to the pitch angle θ0 at that time. Therefore, the process proceeds to step S314, and as a curb climbing cancellation process at this time, the rear height measurement value HR and the front height calculation value HF during constant speed traveling are the same as the rear height measurement value HR0 and the front height calculation value HF0 during stoppage. After that, the process proceeds to step S315, and the pitch angle θ0 when the vehicle is stopped is updated to calculate the pitch angle θ0 when the vehicle is traveling at a constant speed, as in the above equation (1). Next, the process proceeds to step S316, and the target optical axis direction adjustment angle θT (≈−θ0) that does not give glare to the oncoming vehicle is calculated with respect to the pitch angle θ0 during constant speed calculation calculated in step S315. The

  After step S305, step S311 or step S316, the process proceeds to step S317, where the actuator 35 is driven based on the calculated target optical axis direction adjustment angle θT, and this routine is terminated. The control speed setting for the actuator 35 is omitted. For this reason, when the vehicle is turning, the displacement amount ΔHF of the front height calculation value is appropriately corrected, so that there is no inconvenience in the pitch angle θ1, and the vehicle climbs on a curb or the like while the vehicle is stopped. Even if there is an inconvenience in the pitch angle θ0 at that time, the curbstone climbing cancellation process is executed and the pitch angle θ0 is updated once it is determined that the vehicle is traveling at a constant speed without waiting until the end of one trip. After that, the optical axis direction of the headlight 30 is adjusted appropriately.

  FIG. 11 shows the optical axis direction adjustment amount [°] of the vehicle headlight 30 corresponding to the change in the vehicle speed [km / h] when the correction process during the turning of the vehicle is executed based on the flowchart of FIG. It is a time chart.

  As shown in FIG. 11, the direction of the optical axis is deviated when there is no turning determination with respect to the headlight 30 of the vehicle due to an error in the amount of displacement during turning. On the other hand, if the vehicle is turning in response to a change in the vehicle speed [km / h] and the above-described determination condition is satisfied and the calculated front height is the amount of displacement during the turn, there is a turn determination in FIG. As shown, the deviation of the adjustment amount [°] in the optical axis direction of the headlight 30 of the vehicle is eliminated, and the optical axis direction is almost returned to the initial position.

  Thus, the vehicular headlamp optical axis direction automatic adjustment device according to the present modification is disposed at the rear of the vehicle and outputs from the height sensor 11 as one vehicle height sensor that detects the amount of displacement of the vehicle height. Based on the measured rear height HR0 when stopped or the measured rear height HR, the pitch angle θ0 when stopped corresponding to the inclination angle of the headlight (headlight) 30 of the vehicle with respect to the horizontal plane in the optical axis direction or during traveling The inclination angle calculation means achieved by the CPU 21 in the ECU 20 for calculating the pitch angle θ1, and the turning state of the vehicle is the absolute value of | VWR−VWL | which is the absolute value of the deviation between the right wheel speed VWR and the left wheel speed VWL. The turning state determination means achieved by the CPU 21 in the ECU 20 determined based on the height, and the inclination angle calculation based on the determination result of the turning state of the vehicle by the turning state determination means The optical axis direction adjusting means achieved by the CPU 21 in the ECU 20 for correcting the pitch angle θ1 corresponding to the inclination angle during traveling calculated by the means and adjusting the optical axis direction of the headlamp. It is.

  Accordingly, the CPU 21 in the ECU 20 that achieves the inclination angle calculating means is a horizontal plane in the optical axis direction of the headlight 30 based on the measured rear height HR0 during stopping or the measured rear height HR that is output from one height sensor 11. The pitch angle θ0 during stopping or the pitch angle θ1 during traveling corresponding to the inclination angle with respect to the vehicle is calculated, and the optical axis direction adjustment is performed when the CPU 21 in the ECU 20 that achieves the turning state determination means determines that the vehicle is turning. The pitch angle θ1 corresponding to the inclination angle during traveling is corrected by the CPU 21 in the ECU 20 that achieves the means based on the determination result of the turning state of the vehicle at that time, and the optical axis direction of the headlight 30 is adjusted. Thus, when the vehicle is determined to be in a turning state, the pitch angle θ1 during traveling is corrected according to the turning state, so that the deviation in the optical axis direction of the headlight 30 is appropriately adjusted.

  By the way, in the above-described embodiment, the deviation of the left and right wheel speeds is used to determine the turning of the vehicle. However, the present invention is not limited to this, and the steering angle of the steering wheel is used. A certain steering angle may be used.

  In the formulas (1) to (3) of the above embodiment, the pitch angle is calculated after obtaining the front height calculated value from the rear height measurement value once. However, when the front height data is defective, the pitch angle is directly Can also be converted to

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. FIG. 2 is a cross-sectional view showing a main configuration of the headlight of FIG. FIG. 3 is a time for explaining inconveniences when riding on a curb or the like while the vehicle is stopped before the application of the vehicle headlamp optical axis direction automatic adjusting device according to one embodiment of the present invention. It is a chart. FIG. 4 is a rear height measurement value corresponding to a change in the vehicle speed of the vehicle, which is the basis for the headlight optical axis direction adjustment control by the vehicle headlamp optical axis direction automatic adjustment device according to an embodiment of the present invention. It is a time chart which shows the transition state of. FIG. 5 is a process for dealing with climbing on a curb or the like while the vehicle is stopped in the CPU in the ECU used in the vehicle headlamp optical axis direction automatic adjusting device according to one embodiment of the present invention. It is a flowchart which shows a procedure. FIG. 6 is a time chart showing a transition state of each displacement amount corresponding to a change in vehicle speed based on the flowchart of FIG. FIG. 7 is a time chart showing the optical axis direction adjustment amount when there is correction for the vehicle headlamp and the optical axis direction adjustment amount when there is no correction for comparison based on the flowchart of FIG. FIG. 8 is a process for dealing with climbing on a curb or the like while the vehicle is stopped in the CPU in the ECU used in the vehicle headlamp optical axis direction automatic adjusting device according to one embodiment of the present invention. It is a flowchart which shows the modification of a procedure. FIG. 9 is a time chart for explaining inconveniences during turning of the vehicle before application of the vehicle headlamp optical axis direction automatic adjusting device according to an example of the embodiment of the present invention. FIG. 10 shows a vehicle in addition to riding on a curb or the like while the vehicle is stopped by a CPU in the ECU used in the vehicle headlamp optical axis direction automatic adjusting device according to one embodiment of the present invention. It is a flowchart which shows the process sequence which copes with during turning. FIG. 11 is a time chart showing the optical axis direction adjustment amount when there is a turning determination and the optical axis direction adjustment amount when there is no turning determination for comparison according to the flowchart of FIG.

Explanation of symbols

11 Height sensor (vehicle height sensor)
20 ECU (electronic control unit)
30 Headlight (headlight)
35 Actuator

Claims (1)

Rear height measurement value information that is an output from a vehicle height sensor that is disposed at the rear of the vehicle and detects the amount of displacement of the vehicle height;
Calculation means for calculating a front height calculation value as a vehicle height of a front portion of the vehicle based on the rear height measurement value information;
An inclination angle adjusting means for adjusting an inclination angle with respect to a horizontal plane in the optical axis direction of the headlight of the vehicle based on the calculated front height;
Stable running state determining means for determining that the running state of the vehicle is not a stable running state;
Correction means for correcting the front height calculation value calculated by the calculation means based on the determination result of the stable running state of the vehicle by the stable running state determination means;
Comprising a said tilt angle adjusting means may be adjusted based on the inclination angle of the optical axis direction when headlamp said is determined not to be the stable running state in the front height calculation value corrected by said correcting means For the rear height measurement value information and the front height calculation value, a value when the vehicle is stopped is adopted as a reference value, and if the comparison result between the reference value and the value in the stable running state is a predetermined value or more, A vehicle headlamp optical axis direction automatic adjustment device , wherein a value in a stable running state is replaced with a reference value .

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