JP2005067300A - Device for automatically adjusting optical axis direction of headlight for vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce costs and improve reliability by adjusting an optical axis direction of a headlight (a headlamp) by precise determination of a vehicle stop or travel time even eliminating wiring among a vehicle speed sensor, a wheel speed sensor, and an ECU and an input circuit of an ECU side relating thereto. <P>SOLUTION: The vehicle stop or travel time can be determined based on a rear height value HR from a vehicle height sensor 11 by a CPU 21 provided in the ECU 20. The optical axis direction of the headlight 30 is adjusted according to a pitch angle of the vehicle calculated based on the rear height value HR when the vehicle stops. Since the optical axis direction of the headlight 30 is adjusted according to the determination of the vehicle stop or travel time, the wiring from the vehicle speed sensor or the wheel speed sensor does not require being connected to the ECU 20 side and the input circuit of the ECU 20 side relating thereto is not required. Thus, the costs are reduced and the reliability can be improved. <P>COPYRIGHT: (C)2005,JPO&NCIPI

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, a system having a so-called static auto leveling mechanism that relates to a vehicle headlamp optical axis direction automatic adjustment device and automatically adjusts the optical axis direction of the headlamp when the vehicle is stopped, and suppresses or stops control when the vehicle is running It has been known.

As prior art documents related to this, those disclosed in Japanese Patent Application Laid-Open Nos. 2000-85458 and 9-301555 are known. In these devices, a vehicle speed signal based on a vehicle speed sensor or a wheel speed sensor is used to determine when the vehicle is stopped or running. Then, by approximating the amount of change in vehicle posture due to load changes due to vehicle occupants and loading capacity, for example, by linear expression or broken line, basically the optical axis direction of the headlamp is automatically adjusted when the vehicle stops. A technique for suppressing or stopping this adjustment during traveling is shown.
JP 2000-85458 A (pages 2 to 3) Japanese Patent Laid-Open No. 9-301055 (pages 2 to 3)

  By the way, as described above, the vehicle speed signal from the vehicle speed sensor or the wheel speed signal from the wheel speed sensor is used for determination when the vehicle is stopped or running, and this signal is “0 (zero)” or If it is within the predetermined value, the ECU (Electronic Control Unit) determines that the vehicle is stopped. That is, in order to determine when the vehicle is stopped or traveling, it is necessary to input signals from the vehicle speed sensor and the wheel speed sensor to the ECU. This requires wiring for electrically connecting the vehicle speed sensor or wheel speed sensor and the ECU, and an input circuit for taking in this signal is also required on the ECU side. It was impossible to get rid of them. However, from the viewpoint of cost reduction and reliability improvement, there has been a desire to eliminate the vehicle speed sensor, the wiring for electrically connecting the wheel speed sensor and the ECU, and the input circuit on the ECU side related thereto.

  Accordingly, the present invention has been made in response to such a demand, and even when the vehicle speed sensor, the wiring between the wheel speed sensor and the ECU, and the input circuit on the ECU side related thereto are eliminated, the vehicle is stopped or traveled. It is an object of the present invention to provide a vehicle headlamp optical axis direction automatic adjustment device that can adjust the optical axis direction of the headlamp by accurate determination of the above, and can reduce the cost and improve the reliability.

  According to the vehicle headlamp optical axis direction automatic adjustment device of the first aspect of the present invention, when it is determined by the determination means that the vehicle is stopped based on the amount of displacement of the vehicle height from one vehicle height sensor, the inclination angle The optical axis direction of the headlamp is adjusted by the optical axis direction adjusting means in accordance with the inclination angle calculated by the calculating means based on the output from the vehicle height sensor. In other words, it is possible to accurately determine when the vehicle is stopped or running based on the output from the vehicle height sensor without inputting signals from the vehicle speed sensor or the wheel speed sensor. Thus, in order to adjust the optical axis direction of the headlamp according to the determination when the vehicle is stopped or running, it is necessary to connect the wiring from the vehicle speed sensor and the wheel speed sensor to the ECU (electronic control unit) side. In addition, since the input circuit on the ECU side related to this can be eliminated, the cost can be reduced and the reliability can be improved accordingly.

  In the determination means in the vehicle headlamp optical axis direction automatic adjustment device according to claim 2, when the displacement amount of the vehicle height detected by the vehicle height sensor is kept constant, the change in the output from the vehicle height sensor Since the variance value of the quantity remains small without exceeding the predetermined value, it is determined that the vehicle is stopped. On the other hand, when the displacement amount of the vehicle height detected by the vehicle height sensor is always accompanied by a small fluctuation, Since the variance value of the change amount of the output from the high sensor exceeds a predetermined value and is maintained at a large value, it is determined that the vehicle is traveling. Thus, according to the variance value of the amount of change in the output from the vehicle height sensor, it is possible to accurately determine when the vehicle is stopped or running.

  Hereinafter, the best mode for carrying out the present invention will be described based on examples.

  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.

  In FIG. 1, a vehicle height sensor 11 is attached to the axle on the driver seat side or the passenger seat side at the rear of the vehicle. From the vehicle height sensor 11, the rear vehicle height value (the displacement amount of the rear wheel side vehicle height: hereinafter referred to as “rear vehicle height measured value”) is obtained as a relative displacement amount (vehicle height displacement amount) between the rear wheel axle and the vehicle body. Also, various sensor signals and the like are input from an HR and other sensors (not shown) to an ECU (electronic control unit) 20 mounted on the vehicle. The ECU 20 is shown outside the vehicle for convenience.

  The ECU 20 includes a CPU 21 as a central processing unit that executes various known arithmetic processes, a ROM 22 that stores a control program and a control map, a RAM 23 that stores various data, a B / U (backup) RAM 24, an input / output circuit 25, and the like. Is configured as a logical operation circuit including a bus line 26 and the like for connecting the two. 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.

  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, based on the flowchart of FIG. 3 which shows the processing procedure of the optical axis direction adjustment control in CPU21 in ECU20 used with the vehicle headlamp optical axis direction automatic adjustment apparatus concerning one Example of this invention, FIG. A description will be given with reference to FIG. This control routine is repeatedly executed by the CPU 21 every predetermined time. In executing this control routine, a prediction formula table (not shown) necessary for calculating the vehicle pitch angle [°] based on the rear vehicle height value HR [mm] is stored in the ROM 22 in advance.

  Here, FIG. 4 shows the rear vehicle height value HR [mm] corresponding to the occupant's getting on and getting off when the vehicle is stopped, that is, the vehicle speed Vc = 0 [km / h]. : Second] is a time chart showing the transition state of the variance value V of the variation per unit time. Further, FIG. 5 shows a rear vehicle height value HR [mm] corresponding to a vehicle speed Vc [km / h] from when the vehicle is stopped to when it travels at a constant vehicle speed and when the vehicle stops. It is a time chart which shows the transition state of dispersion | distribution value V of the variation | change_quantity per unit time in [sec].

  In FIG. 3, the rear vehicle height value (rear vehicle height measurement value) HR from the vehicle height sensor 11 is read in step S101. Next, the process proceeds to step S102, and the variance value V of the change amount of the rear vehicle height value HR read in step S101 is calculated. Here, the variance value V of the amount of change per unit time during the past 5 [sec] of the rear vehicle height value HR is calculated. An arithmetic expression for obtaining the variance value V is well known and will be omitted.

  Next, the process proceeds to step S103, where it is determined whether the vehicle is at a stop. Specifically, the variance value V calculated in step S102 is compared with the running time determination value or the stopping time determination value, which is a threshold set in advance for determining the running time shown in FIG. 4 or FIG. The In addition, the difference in magnitude between the determination value at the time of traveling and the determination value at the time of stopping is for providing hysteresis characteristics in comparison with the variance value V, and in order to determine the traveling time from when the vehicle is stopped. A determination value at the time of travel is used, and a determination value at the time of stop is used to determine the stop time from the travel time of the vehicle.

  As shown in FIG. 4 or FIG. 5, the rear vehicle height value HR fluctuates greatly due to a change in load load depending on the occupant and the loading amount when the vehicle is stopped, and the value is short when the vehicle is running except during acceleration / deceleration. Small fluctuations with period. For this reason, the variance value V of the change amount of the rear vehicle height value HR temporarily takes a small value when the occupant gets on or off the vehicle when the vehicle is stopped, and becomes “0 (zero)” at other times. . On the other hand, the variance value V of the change amount of the rear vehicle height value HR becomes a large value from “0” at the time of acceleration accompanying the start of traveling of the vehicle. 0 ". Therefore, the dispersion value V is compared with the determination value at the time of traveling or the determination value at the time of stopping, so that the time when the vehicle is stopped or traveling can be known.

  When the determination condition of step S103 is satisfied, that is, when it is determined that the variance value V does not exceed the determination value at the time of travel and the vehicle is stopped, the process proceeds to step S104, and the weak filter f0 (HR) is selected. . On the other hand, when the determination condition of step S103 is not satisfied, that is, when the variance value V exceeds the determination value at the time of travel and is kept equal to or greater than the determination value at the time of stop, and when it is determined that the vehicle is traveling, step S105 is performed. The strong filter f1 (HR) is selected. Then, the process proceeds to step S106, and as the optical axis control value calculation, the pitch angle θp corresponding to the rear vehicle height value HR applied with the filter selected in step S104 or step S105 and read in step S101 is stored in the ROM 22. It is calculated from a table of prediction formulas.

  Here, when the vehicle is stopped, a large pitch angle variation is expected due to a load change due to the occupant and the load, so that the actuator 35 is responded to the pitch angle variation by applying a weak filter f0 (HR). The On the other hand, since fine pitch angle fluctuations due to road surface unevenness are expected when the vehicle is traveling, a strong filter f1 (HR) is applied to remove the pitch angle fluctuations, and the actuator 35 responds to the pitch angle fluctuations. Is not responding. In addition, as a process at the time of driving | running | working of a vehicle, you may make it stop the below-mentioned optical axis control process and maintain the present control angle.

  Next, the process proceeds to step S107, and as an optical axis control process, a target control angle θT (≈−θp) that does not give glare to the oncoming vehicle is calculated with respect to the pitch angle θp calculated in step S106. The actuator 35 is driven based on the target control angle θT, and this routine is finished.

  As described above, the vehicle headlamp optical axis direction automatic adjustment device of the present embodiment is disposed at the rear of the vehicle, and includes one vehicle height sensor 11 that detects the rear vehicle height value HR as a displacement amount of the vehicle height, Based on the rear vehicle height value HR from the vehicle height sensor 11, the determination means achieved by the CPU 21 in the ECU 20 for determining whether the vehicle is stopped or running, and the determination means determined that the vehicle is stopped. Sometimes, this is achieved by the CPU 21 in the ECU 20 that calculates a pitch angle corresponding to the inclination angle of the headlight (headlamp) 30 of the vehicle with respect to the horizontal plane in the optical axis direction based on the rear vehicle height value HR from the vehicle height sensor 11. An inclination angle calculating means, and an optical axis direction adjusting means achieved by the CPU 21 in the ECU 20 for adjusting the optical axis direction of the headlight 30 based on the pitch angle calculated by the inclination angle calculating means. It is intended.

  That is, based on the rear vehicle height value HR from the vehicle height sensor 11, the CPU 21 in the ECU 20 can determine when the vehicle is stopped or running, and the vehicle pitch calculated based on the rear vehicle height value HR when the vehicle is stopped. The optical axis direction of the headlight 30 is adjusted according to the angle. That is, the ECU 20 can determine when the vehicle is stopped or running without inputting a signal from a vehicle speed sensor or a wheel speed sensor, and the vehicle height sensor can be determined by accurate determination when the vehicle is stopped or running. The optical axis direction of the headlight 30 is adjusted based on the rear vehicle height value HR from 11. Thus, in order to adjust the optical axis direction of the headlight 30 according to the determination when the vehicle is stopped or running, it is not necessary to connect the wiring from the vehicle speed sensor or the wheel speed sensor to the ECU 20 side, Since the input circuit on the ECU 20 side related to this can be eliminated, the cost can be reduced and the reliability can be improved accordingly.

  In addition, the determination means achieved by the CPU 21 in the ECU 20 of the vehicle headlamp optical axis direction automatic adjustment device of the present embodiment has a dispersion value V of the amount of change in the output from the vehicle height sensor 11 set in advance. After exceeding the traveling time determination value as a predetermined value, it is determined that the vehicle is traveling when it is held at or above the stopping time determination value.

  That is, when the rear vehicle height value HR detected by the vehicle height sensor 11 is largely fluctuated and the value is kept constant, the variance value V of the change amount of the rear vehicle height value HR is the running time determination value. Therefore, it is determined that the vehicle is at a stop because it remains a small value near “0” without exceeding. On the other hand, when the rear vehicle height value HR detected by the vehicle height sensor 11 is always accompanied by a small fluctuation, the variance value V of the amount of change in the rear vehicle height value HR exceeds the determination value at the time of acceleration at the start of traveling and is a large value. After that, it is determined that the vehicle is running because it is kept at or above the stop time determination value. Thus, according to the variance value V of the change amount of the rear vehicle height value HR detected by the vehicle height sensor 11, it is possible to accurately determine when the vehicle is stopped or running.

  By the way, in the said Example, although the vehicle height sensor 11 is arrange | positioned in the rear part of a vehicle, when implementing this invention, it is not limited to this, A vehicle height sensor is in the front part of a vehicle. Similarly, whether the vehicle is stopped or traveling can be determined based on the output even when the vehicle is disposed or when the vehicle is disposed before and after the vehicle.

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 of FIG. FIG. 3 is a flowchart showing a processing procedure of optical axis direction adjustment control in the CPU in the ECU used in the vehicle headlamp optical axis direction automatic adjustment device according to the embodiment of the present invention. FIG. 4 is a time chart showing transition states of various sensor signals and various control amounts corresponding to the time of stopping in the process of FIG. FIG. 5 is a time chart showing transition states of various sensor signals and various control amounts corresponding to the time of traveling in the process of FIG.

Explanation of symbols

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

Claims (2)

One vehicle height sensor disposed at the front or rear of the vehicle for detecting the amount of vehicle height displacement;
Based on the output from the vehicle height sensor, determination means for determining when the vehicle is stopped or running,
An inclination angle calculating means for calculating an inclination angle of the headlight of the vehicle with respect to a horizontal plane in an optical axis direction based on an output from the vehicle height sensor when the determining means determines that the vehicle is stationary;
An automotive headlamp optical axis direction automatic adjusting device, comprising: an optical axis direction adjusting unit that adjusts an optical axis direction of the headlamp based on the tilt angle calculated by the tilt angle calculating unit. 2. The vehicle front according to claim 1, wherein the determination unit determines that the vehicle is traveling when a variance value of an amount of change in output from the vehicle height sensor exceeds a predetermined value set in advance. Automatic adjustment device for the light axis direction.

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