WO2020031255A1

WO2020031255A1 - Headlamp optical axis control device

Info

Publication number: WO2020031255A1
Application number: PCT/JP2018/029575
Authority: WO
Inventors: 貴夫福永; 大輝川原
Original assignee: 三菱電機株式会社
Priority date: 2018-08-07
Filing date: 2018-08-07
Publication date: 2020-02-13
Also published as: JPWO2020031255A1; JP6765586B2

Abstract

A first tilt angle calculation unit (11) uses the acceleration detected by an acceleration sensor (1) to calculate a tilt angle (θg) of a vehicle relative to a road surface. A second tilt angle calculation unit (12) uses the angular speed detected by an angular speed sensor (2) to calculate a tilt angle (θω) of the vehicle relative to the road surface. A tilt angle selection unit (14) selects the tilt angle (θg) calculated by the first tilt angle calculation unit (11) when a vehicle state determination unit (13) has determined that the vehicle is stopped or traveling with constant speed, and selects the tilt angle (θω) calculated by the second tilt angle calculation unit (12) when the vehicle state determination unit (13) has determined that the vehicle is traveling but not with constant speed. A signal generation unit (15) uses the tilt angle selected by the tilt angle selection unit (14) to generate an optical axis control signal for controlling the optical axis of a headlamp.

Description

Optical axis control device for headlight

The present invention relates to a headlight optical axis control device that controls an optical axis of a headlight of a vehicle.

明るい A bright light source has been demanded for vehicle-mounted headlights so as to brighten the field of view and secure better visibility, or to drive more comfortably. On the other hand, the bright light source of the headlight may be bothering and dazzling to the driver of the oncoming vehicle or the pedestrian on the sidewalk. Based on both, the evolution of in-vehicle headlights has been devised in parallel with the light source that illuminates the front brightly, and the light distribution that does not dazzle from oncoming vehicles.

A typical light distribution for a headlight is a light distribution for a passing light, which irradiates a bright light on a road surface below a line of sight of the driver of an oncoming vehicle, but also emits light above the line including the line of sight. I prevented dazzle by not leaking. The upper and lower boundary lines are cutoff lines.

In addition, even if the vehicle leans forward (nose dive) or leans backward (squat) due to the getting on / off of passengers or loading / unloading of luggage, the headlight is always directed in the same direction. This is performed by the optical axis control device for the lamp. In the above-described control corresponding to the getting on / off of the passenger or the loading / unloading of luggage, slow control is sufficient, and is also referred to as static control. A behavior in which the vehicle rotates around an axis in the left-right direction of the vehicle, such as a forward lean and a backward lean of the vehicle, is expressed as pitching.

By the way, new light sources such as discharge lamps and LEDs (Light Emitting Diodes), which are brighter than conventional incandescent lamps that glow a tungsten filament, have become widespread as headlight light sources. The bright light source provides the driver with a bright field of view and provides better visibility or a more comfortable driving environment even at night. However, as compared with incandescent lamps and the like, discharge lamps and LEDs and the like have a larger difference in brightness between the upper and lower sides of the cutoff line. Therefore, when the vehicle is stopped or running smoothly, the road surface below the eyes of the driver of the oncoming vehicle can be illuminated by the control that keeps the irradiation direction of the headlight constant, However, the slow control described above cannot follow the backward tilt during vehicle acceleration, and the boundary between the light and dark areas separated by the cutoff line moves toward the own vehicle, and the driver is informed of the own vehicle. It can give discomfort to make the sway of the rocks even greater.

Therefore, by quickly performing control to always direct the irradiation direction of the headlight in the same direction, the response to the getting on / off of the passenger or the loading / unloading of the luggage is quicker, and the forward leaning at the time of vehicle deceleration or the backward leaning at the time of vehicle acceleration are performed. A corresponding control has been proposed (for example, see Patent Document 1). The quick control of the irradiation direction is also called dynamic control in contrast to the static control.

The optical axis direction adjusting device according to Patent Document 1 controls the optical axis of the headlight using an acceleration sensor that detects the acceleration of the vehicle and an angular velocity sensor that detects the angular velocity of the vehicle in the pitching angle direction.

JP 2009-126268 A

The conventional headlamp optical axis control device uses an acceleration sensor in addition to an angular velocity sensor capable of quickly detecting the forward inclination and the backward inclination of the vehicle in order to increase the control accuracy of the optical axis. However, the conventional headlamp optical axis control device selectively uses the vehicle inclination angle based on the value of the angular velocity sensor and the vehicle inclination angle based on the value of the acceleration sensor according to the situation of the vehicle. Did not.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and performs slow control and quick control of an optical axis with high accuracy by properly using an acceleration sensor and an angular velocity sensor having different characteristics. With the goal.

The headlamp optical axis control device according to the present invention calculates a tilt angle of the vehicle with respect to a road surface by using the longitudinal acceleration and the vertical acceleration of the vehicle detected by an acceleration sensor mounted on the vehicle. (1) an inclination angle calculation unit, a second inclination angle calculation unit that calculates an inclination angle of the vehicle with respect to a road surface using an angular velocity when the vehicle rotates back and forth, detected by an angular velocity sensor mounted on the vehicle, and an acceleration sensor Using the detected acceleration and the angular velocity detected by the angular velocity sensor, a vehicle state determination unit that determines the state of the vehicle, and when it is determined that the vehicle is stopped or running at a constant speed by the vehicle state determination unit, Adopting the inclination angle of the first inclination angle calculation unit, if the vehicle state determination unit determines that the vehicle is traveling but is not traveling at a constant speed, the inclination of the second inclination angle calculation unit is determined. A tilt angle adoption unit that employs an angle, and a signal generation unit that generates an optical axis control signal for controlling the optical axis of the headlight mounted on the vehicle using the tilt angle adopted by the tilt angle adoption unit. It is provided with.

According to the present invention, when the vehicle is stopped or traveling at a constant speed, the inclination angle based on the value of the acceleration sensor is employed. When the vehicle is traveling but is not traveling at the constant speed, the value of the angular velocity sensor is used. Since the inclination angle based on the angle is adopted, slow control and quick control of the optical axis can be performed with high accuracy by properly using the acceleration sensor and the angular velocity sensor having different characteristics.

FIG. 2 is a block diagram illustrating a configuration example of a headlight optical axis control device according to the first embodiment. FIG. 3 is a diagram illustrating acceleration and a tilt angle of a vehicle according to the first embodiment. FIG. 3 is a diagram illustrating an angular velocity and an inclination angle of a vehicle according to the first embodiment. 5 is a flowchart illustrating an operation example of the headlight optical axis control device according to the first embodiment. FIG. 4 is a diagram illustrating a change in the angle of a stopped vehicle in the first embodiment. FIG. 4 is a diagram illustrating a change in the angle of a vehicle that is traveling at a constant speed in the first embodiment. FIG. 3 is a diagram illustrating a change in the angle of the vehicle during uphill traveling in the first embodiment. FIG. 5 is a diagram illustrating a change in the angle of the vehicle during acceleration in the first embodiment. FIG. 4 is a diagram illustrating a change in the angle of the vehicle during traveling in the concave portion in the first embodiment. FIG. 7 is a block diagram illustrating a configuration example of a headlight optical axis control device according to a second embodiment. 9 is a flowchart illustrating an operation example of the headlight optical axis control device according to the second embodiment. 9 is a flowchart illustrating a modification of the operation of the headlight optical axis control device according to the second embodiment. FIGS. 13A and 13B are diagrams illustrating a hardware configuration example of the headlamp optical axis control device 10 according to each embodiment.

Hereinafter, in order to explain this invention in greater detail, the preferred embodiments of the present invention will be described with reference to the accompanying drawings.
Embodiment 1 FIG.
FIG. 1 is a block diagram illustrating a configuration example of a headlamp optical axis control device 10 according to the first embodiment. The headlight optical axis control device 10 is mounted on a vehicle and controls the optical axis of the headlight. The headlamp optical axis control device 10 is connected to an acceleration sensor 1, an angular velocity sensor 2, a vehicle speed sensor 3, an accelerator opening sensor 4, and an optical axis control actuator 5 mounted on a vehicle.

The acceleration sensor 1 detects the longitudinal acceleration and the vertical acceleration of the vehicle, and outputs the detected acceleration to the headlight optical axis control device 10. The angular velocity sensor 2 detects an angular velocity when the vehicle rotates back and forth, and outputs the detected angular velocity to the headlight optical axis control device 10. The acceleration sensor 1 and the angular velocity sensor 2 may be built in the headlight optical axis control device 10.

The vehicle speed sensor 3 detects the vehicle speed and outputs the detected vehicle speed to the headlight optical axis controller 10. The accelerator opening sensor 4 detects the accelerator opening of the vehicle, and outputs the detected accelerator opening to the headlight optical axis controller 10.

The optical axis control actuator 5 operates the angle of the optical axis of the headlight according to the optical axis control signal output from the headlight optical axis control device 10. By the angle operation of the optical axis by the optical axis control actuator 5, the irradiation direction of the headlight changes so as to cancel the change in the inclination angle of the vehicle. Thereby, even if the inclination angle of the vehicle changes, the optical axis of the headlight with respect to the road surface is kept constant.

The headlight optical axis control device 10 includes a first inclination angle calculation unit 11, a second inclination angle calculation unit 12, a vehicle state determination unit 13, an inclination angle adoption unit 14, and a signal generation unit 15.

The first inclination angle calculation unit 11 calculates the inclination angle θg of the vehicle with respect to the road surface using the longitudinal acceleration and the vertical acceleration of the vehicle detected by the acceleration sensor 1. The first tilt angle calculation unit 11 outputs the calculated tilt angle θg to the tilt angle adoption unit 14. The first inclination angle calculation unit 11 calculates the inclination angle θg by, for example, a method described in International Publication No. WO 2016/189707. Hereinafter, a method of calculating the inclination angle θg will be briefly described.

FIG. 2 is a diagram for explaining the acceleration and the inclination angle of the vehicle in the first embodiment. Here, an acceleration measurement system is used in which the X-axis is the longitudinal direction of the vehicle and the Z-axis is the vertical direction, and the direction and magnitude of the acceleration applied to the vehicle are represented by the position of the weight suspended by the spring. Also, if a planar quadrilateral having four center points of front, rear, left, and right wheels grounded on the road surface as four vertices is regarded as a virtual bogie, the plane of the virtual bogie is parallel to the road surface. Therefore, the angle θ formed between the virtual truck and the vehicle body supported by the suspension on the truck is the inclination angle of the vehicle with respect to the road surface. FIG. 2 shows the behavior of the weight as viewed from the virtual bogie of the vehicle. Note that in FIG. 2, the front-rear direction of the virtual truck is an Xi axis, and the up-down direction is a Zi axis.

錘 When the vehicle accelerates as shown in FIG. 2, the weight moves parallel to the road surface whether on a horizontal road or on a slope. In other words, the weight moves in the Xi-axis direction of the virtual bogie. That is, the change in acceleration due to the running of the vehicle is parallel to the road surface, that is, as indicated by an arrow 20 in the Xi-axis direction of the virtual bogie. On the other hand, the X axis during vehicle acceleration is inclined at an angle θ with respect to the angle of the road surface. At this time, the behavior of the weight as viewed from the acceleration measurement system mounted on the vehicle body moves by ΔX in the X-axis direction and ΔZ in the Z-axis direction. Therefore, the inclination angle θg of the vehicle with respect to the road surface is expressed by Expression (1). You.

θg = tan ⁻¹ (ΔZ / ΔX) (1)

Therefore, in the acceleration measurement system mounted on the vehicle body, the amount of movement of the weight moving in parallel to the road surface at the two points of time (the reference time point km before the vehicle accelerates / decelerates) and the time point kn during the acceleration / deceleration (arrow) 20) That is, by observing the difference between the vertical acceleration (ΔZ) and the difference between the longitudinal acceleration (ΔX), the inclination angle θg of the vehicle with respect to the road surface can be calculated regardless of the gradient of the road on which the vehicle is traveling. it can.

The first inclination angle calculation unit 11 calculates the longitudinal acceleration and the vertical acceleration detected by the acceleration sensor 1 when the vehicle is traveling at a constant acceleration, in the longitudinal acceleration and the vertical acceleration at the reference time km. It is desirable to use an acceleration of By using the acceleration at the time of running at the constant acceleration, the changing acceleration, that is, the difference between the accelerations can be easily detected, so that a highly reliable inclination angle θg can be obtained. The determination as to whether or not the vehicle is traveling at a constant acceleration is made by a vehicle state determination unit 13 described later.
Further, the first inclination angle calculation unit 11 may output an average value, a median value, or the like obtained from the plurality of inclination angles θg to the inclination angle adoption unit 14. Thereby, a more reliable inclination angle θg can be obtained.

The second tilt angle calculating unit 12 calculates the tilt angle θω of the vehicle with respect to the road surface using the angular speed detected by the angular speed sensor 2 when the vehicle rotates back and forth, that is, the angular speed in the pitching angle direction. The second tilt angle calculation unit 12 outputs the calculated tilt angle θω to the tilt angle adoption unit 14.

FIG. 3 is a diagram illustrating the angular velocity and the inclination angle of the vehicle according to the first embodiment. FIG. 3 shows the sampling time of the angular velocity, the actual inclination angle of the vehicle, the angular velocity detected by the angular velocity sensor 2, and the integrated value of the angular velocity when the vehicle accelerates. When the sampling time is 0 [ms], the vehicle is stopped, and the inclination angle of the vehicle is 0 [degree]. During the sampling time of 0 [ms] to 50 [ms], the vehicle accelerates, and the vehicle leans backward due to the acceleration. Therefore, the inclination angle of the vehicle becomes 1 [degree] after 50 [ms]. During the sampling time of 50 [ms] to 100 [ms], the vehicle travels at a constant acceleration, and the inclination angle of the vehicle maintains 1 [degree]. During a sampling time of 100 [ms] to 150 [ms], the vehicle travels at a constant speed, and after 150 [ms], the inclination angle of the vehicle becomes 0 [degree].

(3) As shown in FIG. 3, the angular velocity sensor 2 detects an angle change at regular time intervals. Therefore, the second inclination angle calculation unit 12 integrates the angular velocities every 10 [ms], and sets the integrated value every 10 [ms] as the inclination angle θω with respect to the road surface of the vehicle. As described above, since the second inclination angle calculation unit 12 can obtain the inclination angle θω at each sampling time, the second inclination angle calculation unit 12 can quickly detect the forward inclination and the backward inclination of the vehicle as compared with the first inclination angle calculation unit 11. Can be.

The vehicle state determination unit 13 determines the state of the vehicle using a value detected by at least one of the acceleration sensor 1, the angular velocity sensor 2, the vehicle speed sensor 3, and the accelerator opening sensor 4. The state of the vehicle includes at least one of stopping, traveling, traveling at a constant speed, or traveling at an equal acceleration. The vehicle state determination unit 13 outputs the determination result to the inclination angle adoption unit 14.

The vehicle state determination unit 13 determines whether the vehicle is running or stopped using the vehicle speed detected by the vehicle speed sensor 3, for example. In addition, when the vehicle is traveling, the longitudinal acceleration detected by the acceleration sensor 1 is a value other than zero and the angular velocity detected by the angular velocity sensor 2 is zero during traveling of the vehicle. Is determined to be running at a constant acceleration. In addition, the vehicle state determination unit 13 determines that the vehicle is traveling at a constant velocity when the longitudinal acceleration detected by the acceleration sensor 1 is zero and the angular velocity detected by the angular velocity sensor 2 is zero during traveling of the vehicle. It is determined that the vehicle is running.

The tilt angle adoption unit 14 receives the tilt angle θg from the first tilt angle calculation unit 11, the tilt angle θω from the second tilt angle calculation unit 12, and the determination result from the vehicle state determination unit 13. When the vehicle state determination unit 13 determines that the vehicle is stopped or running at a constant speed, the inclination angle adoption unit 14 adopts the inclination angle θg of the first inclination angle calculation unit 11 and employs the adopted inclination angle θg. Is output to the signal generation unit 15. On the other hand, when the vehicle state determination unit 13 determines that the vehicle is traveling but is not traveling at a constant speed, the inclination angle adoption unit 14 adopts and employs the inclination angle θω of the second inclination angle calculation unit 12. The inclination angle θω is output to the signal generator 15. When the vehicle state determination unit 13 determines that there is a change in the accelerator opening of the vehicle during traveling at a constant speed, the inclination angle adoption unit 14 outputs the signal to the signal generation unit 15 without using the inclination angles θg and θω. do not do.

The signal generation unit 15 uses the tilt angle θg or the tilt angle θω adopted by the tilt angle adoption unit 14 and emits light for rotating the optical axis of the headlight in a direction opposite to the tilt angle θg or the tilt angle θω. Generate an axis control signal. The signal generation unit 15 outputs the generated optical axis control signal to the optical axis control actuator 5 so that the optical axis control actuator 5 controls the optical axis of the headlight so as to prevent dazzling of an oncoming vehicle driver or the like. Control.

Next, the operation of the headlamp optical axis control device 10 according to the first embodiment will be described.
FIG. 4 is a flowchart illustrating an operation example of the headlamp optical axis control device 10 according to the first embodiment. The headlight optical axis control device 10 repeats the flow chart of FIG. 4 during its operation.

In step ST11, the first inclination angle calculation unit 11 calculates the inclination angle θg of the vehicle using the acceleration detected by the acceleration sensor 1. In step ST12, the second inclination angle calculation unit 12 calculates the inclination angle θω of the vehicle using the angular velocity detected by the angular velocity sensor 2.

In step ST13, the vehicle state determination unit 13 determines the state of the vehicle using the detection values detected by the acceleration sensor 1, the angular velocity sensor 2, the vehicle speed sensor 3, and the accelerator opening sensor 4.

When the vehicle state determination unit 13 determines that the vehicle is stopped (“YES” in step ST14), the inclination angle adoption unit 14 employs the inclination angle θg of the first inclination angle calculation unit 11 in step ST15. . In step ST16, the signal generation unit 15 generates an optical axis control signal using the inclination angle θg of the first inclination angle calculation unit 11, and outputs the signal to the optical axis control actuator 5. A specific example will be described with reference to FIG.

When the vehicle state determination unit 13 determines that the vehicle is traveling (step ST14 “NO”) and determines that the vehicle is not traveling at the constant speed (step ST17 “NO”), in step ST18, The inclination angle adoption unit 14 employs the inclination angle θω of the second inclination angle calculation unit 12. Thereafter, in step ST16, the signal generation unit 15 generates an optical axis control signal using the inclination angle θω of the second inclination angle calculation unit 12, and outputs the signal to the optical axis control actuator 5. A specific example will be described with reference to FIGS. 8 and 9 described later.

When the vehicle state determination unit 13 determines that the vehicle is traveling at a constant speed (“YES” in step ST17) and determines that there is a change in the accelerator opening (step ST19 “YES”), the vehicle is on a slope. , The headlight optical axis control device 10 keeps the headlight optical axis unchanged. That is, the signal generation unit 15 maintains the optical axis control signal generated immediately before (for example, when the operation illustrated in the flowchart of FIG. 4 is performed last time). A specific example will be described with reference to FIG.

If the vehicle state determination unit 13 determines that the vehicle is traveling at a constant speed (“YES” in step ST17) and determines that there is no change in the accelerator opening (“NO” in step ST19), the process proceeds to step ST15. The inclination angle adoption unit 14 employs the inclination angle θg of the first inclination angle calculation unit 11. In step ST16, the signal generation unit 15 generates an optical axis control signal using the inclination angle θg of the first inclination angle calculation unit 11, and outputs the signal to the optical axis control actuator 5. A specific example will be described with reference to FIG.

Next, a specific example of the optical axis control of the headlight optical axis control device 10 will be described with reference to FIGS. In FIGS. 5 to 9, for convenience, the values detected by the respective sensors and the values such as the inclination angle of the vehicle are described. However, these values are reference values and are different from actual values.

FIG. 5 is a diagram illustrating a change in the angle of a stopped vehicle in the first embodiment. In the example of FIG. 5, the angle of the vehicle is changed by loading and unloading luggage at the rear of the stopped vehicle.
When the vehicle state determination unit 13 determines that the vehicle is stopped, the vehicle is in a static state, and thus the optical axis control may be slow. Therefore, the inclination angle adoption unit 14 employs the inclination angle θg, which has low responsiveness but high reliability, based on the acceleration sensor 1 and calculated by the first inclination angle calculation unit 11. The signal generation unit 15 generates an optical axis control signal for controlling the optical axis to be lowered when the inclination angle θg is increased, that is, when the front of the vehicle is directed upward. On the other hand, when the inclination angle θg is reduced, that is, when the front of the vehicle is directed downward, the signal generation unit 15 generates an optical axis control signal for controlling the optical axis to be raised.

FIG. 6 is a diagram illustrating a change in the angle of the vehicle while traveling at a constant speed in the first embodiment. When determining that the vehicle is traveling at a constant speed, the vehicle state determination unit 13 subsequently checks a change in the accelerator opening. When the vehicle state determination unit 13 determines that the vehicle is traveling at a constant speed and there is no change in the accelerator opening, it is estimated that the angle of the road surface on which the vehicle is traveling at a constant speed has not changed. You. In a constant speed running state where there is no change in the road surface angle, no change in the inclination angle (i.e., swing) of the vehicle due to acceleration / deceleration occurs, and it is assumed that the vehicle is in a static state. Therefore, the inclination angle adoption unit 14 employs the inclination angle θg calculated by the first inclination angle calculation unit 11 and based on the acceleration sensor 1.

FIG. 7 is a diagram illustrating a change in the angle of the vehicle during uphill traveling in the first embodiment. FIG. 6 shows an example in which the angle of the road surface does not change while the vehicle is traveling at a constant speed, but FIG. 7 shows an example in which the angle of the road surface changes while the vehicle is traveling at a constant speed. In FIG. 7, the horizontal inclination angle is the inclination angle of the vehicle with respect to the horizontal plane, and the road surface inclination angle is the inclination angle of the vehicle with respect to the road surface.
If the road surface angle changes while the vehicle is traveling at a constant speed, the headlight optical axis control device 10 may erroneously detect a change in the road surface angle as a change in the inclination angle of the vehicle. For example, if the road changes from a flat road to an upward slope during traveling at a constant speed, the headlamp optical axis control device 10 determines that the front of the vehicle is facing upward, and may erroneously lower the optical axis.

Therefore, the vehicle state determination unit 13 determines whether or not the road has changed from a flat road to a slope based on the change in the accelerator opening. In order for the road surface on which the vehicle is traveling to change from a flat road to an upward slope and to maintain a constant speed traveling, the driver needs to strongly depress the accelerator. In FIG. 7, the case where the accelerator is depressed strongly is represented as “(+ α)”. Conversely, in order for the road surface on which the vehicle is traveling to change from a flat road to a downhill slope and to maintain the constant speed traveling, the driver needs to weaken the accelerator pedal. Such an accelerator operation is similarly performed when the road surface changes from a slope to a flat road. That is, it is presumed that the case where the accelerator opening changes while the vehicle is traveling at a constant speed is the case where the angle of the road surface changes. Therefore, when the vehicle state determination unit 13 determines that the vehicle is traveling at a constant speed and that the accelerator opening changes, the inclination angle adoption unit 14 does not employ any of the inclination angles θg and θω. , The signal generator 15 does not perform optical axis control. On the other hand, while the vehicle is traveling at a constant speed on the slope and there is no change in the accelerator opening, the inclination angle adoption unit 14 calculates the inclination angle based on the acceleration sensor 1 calculated by the first inclination angle calculation unit 11. Adopt θg.

FIG. 8 is a diagram illustrating a change in the angle of the vehicle during acceleration in the first embodiment. A vehicle traveling on a flat road swings due to acceleration and deceleration, and the inclination angle changes. That is, when the accelerator opening of the vehicle changes and the vehicle speed changes accordingly, it is estimated that the vehicle is rocking due to acceleration and deceleration. When the vehicle is traveling and swinging, the method of calculating the inclination angle θg using the acceleration at two points in time is not suitable because the response of the inclination angle θg to the swing is low. Therefore, when the vehicle state determination unit 13 determines that the vehicle is traveling and swinging, the inclination angle adoption unit 14 responds based on the angular velocity sensor 2 calculated by the second inclination angle calculation unit 12. Is adopted.

FIG. 9 is a diagram illustrating a change in the angle of the vehicle during traveling in the concave portion in the first embodiment. When the vehicle traveling at a constant speed travels on a concave or convex portion of the road surface, the change in the inclination angle θω calculated using the angular velocity coincides with the appropriate optical axis control direction. For example, as shown in FIG. 9, when the front wheels of the vehicle run in the concave portions, the front of the vehicle moves upward from below, so it is necessary to raise the optical axis and then lower it. Further, when the rear wheel of the vehicle travels in the recess, the front of the vehicle moves from top to bottom, so it is necessary to raise the optical axis after lowering the optical axis. As described above, while the vehicle is oscillating by traveling on the concave portion or the convex portion, the inclination angle adoption section 14 has high responsiveness based on the angular velocity sensor 2 calculated by the second inclination angle calculation section 12. The inclination angle θω is adopted.

As described above, the headlamp optical axis control device 10 according to the first embodiment includes the first inclination angle calculation unit 11, the second inclination angle calculation unit 12, the vehicle state determination unit 13, the inclination angle adoption unit 14, And a signal generation unit 15. The first inclination angle calculation unit 11 calculates the inclination angle θg of the vehicle with respect to the road surface using the acceleration in the front-rear direction and the acceleration in the vertical direction of the vehicle detected by the acceleration sensor 1 mounted on the vehicle. The second tilt angle calculation unit 12 calculates the tilt angle θω of the vehicle with respect to the road surface using the angular speed at which the vehicle rotates back and forth, detected by the angular speed sensor 2 mounted on the vehicle. The vehicle state determination unit 13 determines the state of the vehicle using the acceleration detected by the acceleration sensor 1 and the angular velocity detected by the angular velocity sensor 2. When the vehicle state determination unit 13 determines that the vehicle is stopped or running at a constant speed, the inclination angle adoption unit 14 employs the inclination angle θg of the first inclination angle calculation unit 11 and the vehicle state determination unit 13 When it is determined that the vehicle is traveling but is not traveling at a constant speed, the inclination angle θω of the second inclination angle calculation unit 12 is adopted. The signal generation unit 15 generates an optical axis control signal for controlling the optical axis of the headlight mounted on the vehicle using the inclination angle θg or the inclination angle θω adopted by the inclination angle adoption unit 14. As described above, the headlight optical axis control device 10 employs the highly reliable inclination angle θg based on the acceleration sensor 1 when the vehicle is stopped or traveling at a constant speed, and the vehicle is traveling. Therefore, when the vehicle is oscillating, the inclination angle θω having high responsiveness based on the angular velocity sensor 2 is adopted. Therefore, by selectively using the angular velocity sensor 2 and the acceleration sensor 1 having different characteristics, slow control and quick control of the optical axis can be performed with high accuracy.

Further, the first inclination angle calculation unit 11 of the first embodiment uses the acceleration in the longitudinal direction at two time points km and kn detected by the acceleration sensor 1 and the acceleration in the vertical direction at the two time points km and kn. The angle θg is calculated. Then, the first inclination angle calculation unit 11 compares the acceleration in the longitudinal direction and the acceleration in the vertical direction at one of the two time points km and kn with the acceleration in the longitudinal direction when the vehicle is traveling at an equal acceleration. The acceleration and the vertical acceleration are used. Accordingly, the first inclination angle calculation unit 11 can accurately calculate the inclination angle θg of the stationary vehicle that is not swinging.

The vehicle state determination unit 13 of the first embodiment determines that the vehicle is traveling at a constant acceleration when the longitudinal acceleration is other than zero and the angular velocity is zero during traveling of the vehicle. Accordingly, the vehicle state determination unit 13 can perform the determination with higher accuracy than when determining whether the vehicle is traveling at a constant acceleration using the vehicle speed.

The vehicle state determination unit 13 of the first embodiment determines that the vehicle is traveling at a constant speed when the longitudinal acceleration is zero and the angular velocity is zero during traveling of the vehicle. Thereby, the vehicle state determination unit 13 can determine with higher accuracy than when determining whether the vehicle is traveling at a constant speed using the vehicle speed.

車両 Furthermore, the vehicle state determination unit 13 of the first embodiment determines whether or not the accelerator opening of the vehicle has changed. The inclination angle adoption unit 14 employs the inclination angle θg of the first inclination angle calculation unit 11 when the vehicle state determination unit 13 determines that the vehicle is traveling at a constant speed and there is no change in the accelerator opening. Accordingly, when the vehicle is in a static state, the headlight optical axis control device 10 can perform highly accurate optical axis control based on the highly reliable acceleration sensor 1.

Further, when the vehicle state determination unit 13 determines that the vehicle is traveling at a constant speed and the accelerator opening is changed, the signal generation unit 15 of the first embodiment maintains the optical axis control signal generated before that. . Thus, the headlamp optical axis control device 10 can prevent erroneous optical axis control when the angle of the road surface changes.

Embodiment 2 FIG.
FIG. 10 is a block diagram showing a headlight optical axis control device 10 according to the second embodiment. The headlight optical axis control device 10 according to the second embodiment has a configuration in which a calibration unit 14a is added to the headlight optical axis control device 10 of the first embodiment shown in FIG. . 10, the same or corresponding parts as those in FIG. 1 are denoted by the same reference numerals, and description thereof will be omitted.

The calibration unit 14a calibrates the inclination angle θω of the second inclination angle calculation unit 12. Here, two methods of the calibration method shown in FIG. 11 and the calibration method shown in FIG. 12 will be exemplified.

FIG. 11 is a flowchart illustrating an operation example of the headlamp optical axis control device 10 according to the second embodiment. Steps ST11 to ST19 in FIG. 11 are the same as steps ST11 to ST19 in FIG.
Although the angular velocity sensor 2 has high responsiveness, the inclination angle θω may deviate from the actual inclination angle of the vehicle when used for a long time due to the property of accumulating the angular velocity for each sampling time. Therefore, it is desirable to calibrate the inclination angle θω. Therefore, when the inclination angle adoption unit 14 employs the highly reliable inclination angle θg based on the acceleration sensor 1 (step ST15), in step ST21, the calibration unit 14a determines the inclination angle of the second inclination angle calculation unit 12 The inclination angle θω is calibrated by overwriting θω with the inclination angle θg of the first inclination angle calculation unit 11. Thereafter, the second inclination angle calculation unit 12 obtains the inclination angle θω by integrating the angular velocity detected by the angular velocity sensor 2 with the corrected inclination angle θω.

FIG. 12 is a flowchart illustrating a modification of the operation of the headlight optical axis control device 10 according to the second embodiment. Steps ST11 to ST19 and ST21 in FIG. 12 are the same as steps ST11 to ST19 and ST21 in FIG. 4 and FIG.
When there is a difference between the sensitivity of the acceleration sensor 1 and the sensitivity of the angular velocity sensor 2, even if the calibration unit 14a calibrates the inclination angle θω in step ST21 of FIG. 11, an error having the same tendency occurs again in the inclination angle θω. . Thus, the calibrating unit 14a determines that the difference between the inclination angle θg of the first inclination angle calculation unit 11 and the inclination angle θω of the second inclination angle calculation unit 12 is larger than a predetermined threshold value θth (“YES” in step ST22). In step ST23, the sensitivity of the angular velocity sensor 2 is calibrated. On the other hand, when the difference between the inclination angle θg of the first inclination angle calculation unit 11 and the inclination angle θω of the second inclination angle calculation unit 12 is equal to or less than the threshold value θth (“NO” in step ST22), the calibration unit 14a determines the angular velocity. Do not calibrate the sensitivity of sensor 2. The tilt angle θω used for comparison with the tilt angle θg in step ST22 is the tilt angle θω before being overwritten with the tilt angle θg in step ST21, that is, the tilt angle θω before calibration.

For example, the relationship between the inclination angle θg of the first inclination angle calculation unit 11 and the inclination angle θω of the second inclination angle calculation unit 12 is expressed by Expression (2). In this case, the calibration unit 14a may calibrate the coefficient k of Expression (2) or calibrate the offset θo as the calibration of the sensitivity of the angular velocity sensor 2.

θg = kθω + θo (2)

FIG. 12 shows an example in which the calibrating unit 14a performs an operation of calibrating the inclination angle θω (step ST21) and an operation of calibrating the sensitivity of the angular velocity sensor 2 (steps ST22 and ST23). The unit 14a may execute only the operation of calibrating the sensitivity of the angular velocity sensor 2 (step ST22 and step ST23).

As described above, the headlight optical axis control device 10 according to the second embodiment includes the calibration unit 14a. When the inclination angle adoption unit 14 adopts the inclination angle θg of the first inclination angle calculation unit 11, the calibration unit 14 a uses the adopted inclination angle θg to calibrate the inclination angle θω of the second inclination angle calculation unit 12. I do. Thereby, the headlamp optical axis control device 10 can perform highly accurate optical axis control using the angular velocity sensor 2.

In addition, the calibration unit 14a according to the second embodiment determines the angular velocity when the difference between the inclination angle θg of the first inclination angle calculation unit 11 and the inclination angle θω of the second inclination angle calculation unit 12 is larger than a predetermined threshold value θth. Calibrate the sensitivity of sensor 2. Thereby, the headlamp optical axis control device 10 can perform highly accurate optical axis control using the angular velocity sensor 2.

Lastly, a hardware configuration of the headlamp optical axis control device 10 according to each embodiment will be described.
13A and 13B are diagrams illustrating a hardware configuration example of the headlamp optical axis control device 10 according to each embodiment. The functions of the first inclination angle calculation unit 11, the second inclination angle calculation unit 12, the vehicle state determination unit 13, the inclination angle adoption unit 14, the calibration unit 14a, and the signal generation unit 15 in the headlight optical axis control device 10 are as follows. Is realized by a processing circuit. That is, the headlamp optical axis control device 10 includes a processing circuit for realizing the above functions. The processing circuit may be the processing circuit 100 as dedicated hardware, or may be the processor 101 that executes a program stored in the memory 102.

As illustrated in FIG. 13A, when the processing circuit is dedicated hardware, the processing circuit 100 includes, for example, a single circuit, a composite circuit, a programmed processor, a parallel programmed processor, and an ASIC (Application / Specific / Integrated / Circuit). ), FPGA (Field Programmable Gate Array), or a combination thereof. Even if the functions of the first inclination angle calculation unit 11, the second inclination angle calculation unit 12, the vehicle state determination unit 13, the inclination angle adoption unit 14, the calibration unit 14a, and the signal generation unit 15 are realized by a plurality of processing circuits 100. Alternatively, the functions of the respective units may be collectively realized by one processing circuit 100.

As shown in FIG. 13B, when the processing circuit is the processor 101, the first inclination angle calculation unit 11, the second inclination angle calculation unit 12, the vehicle state determination unit 13, the inclination angle adoption unit 14, the calibration unit 14a, and The function of the signal generation unit 15 is realized by software, firmware, or a combination of software and firmware. Software or firmware is described as a program and stored in the memory 102. The processor 101 reads out and executes a program stored in the memory 102 to realize the function of each unit. That is, the headlamp optical axis control device 10 stores a program that, when executed by the processor 101, results in the steps shown in the flowcharts of FIGS. 4, 11, and 12 being executed. And a memory 102 for storing the information. In addition, this program causes a computer to execute the procedure or method of the first inclination angle calculation unit 11, the second inclination angle calculation unit 12, the vehicle state determination unit 13, the inclination angle adoption unit 14, the calibration unit 14a, and the signal generation unit 15. It can be said that it is something to be executed.

Here, the processor 101 is a CPU (Central Processing Unit), a processing device, an arithmetic device, a microprocessor, or the like.
The memory 102 may be a nonvolatile or volatile semiconductor memory such as a RAM (Random Access Memory), a ROM (Read Only Memory), an EPROM (Erasable Programmable ROM), or a flash memory, or a hard disk or a flexible disk. May be used, or an optical disk such as a CD (Compact Disc) or a DVD (Digital Versatile Disc) may be used.

Note that some of the functions of the first inclination angle calculation unit 11, the second inclination angle calculation unit 12, the vehicle state determination unit 13, the inclination angle adoption unit 14, the calibration unit 14a, and the signal generation unit 15 are partially dedicated hardware. And a part thereof may be realized by software or firmware. As described above, the processing circuit in the headlight optical axis control device 10 can realize the above-described functions by hardware, software, firmware, or a combination thereof.

は Within the scope of the present invention, any combination of the embodiments, modification of any component of each embodiment, or omission of any component of each embodiment is possible within the scope of the present invention.

The headlight optical axis control device according to the present invention uses the value of the acceleration sensor and the value of the angular velocity sensor properly according to the state of the vehicle, and thus performs static control and dynamic control of the optical axis of the headlight. It is suitable for use in a headlight optical axis control device and the like.

1 acceleration sensor, 2 angular velocity sensor, 3 vehicle speed sensor, 4 accelerator opening sensor, 5 optical axis control actuator, 10 headlight optical axis control device, 11 first inclination angle calculation unit, 12 second inclination angle calculation unit, 13 {vehicle state determination section, 14} inclination angle adoption section, 14a {calibration section, 15} signal generation section, 100 # processing circuit, 101 # processor, 102 # memory.

Claims

A first inclination angle calculation unit that calculates an inclination angle of the vehicle with respect to a road surface using the longitudinal acceleration and the vertical acceleration of the vehicle detected by an acceleration sensor mounted on the vehicle;
A second inclination angle calculation unit that calculates an inclination angle of the vehicle with respect to a road surface using an angular velocity when the vehicle rotates back and forth detected by an angular velocity sensor mounted on the vehicle;
A vehicle state determination unit that determines the state of the vehicle using the acceleration detected by the acceleration sensor and the angular velocity detected by the angular velocity sensor,
When the vehicle state determination unit determines that the vehicle is stopped or traveling at a constant speed, the vehicle state determination unit adopts the inclination angle of the first inclination angle calculation unit, and the vehicle state determination unit determines that the vehicle is traveling. When it is determined that the vehicle is not traveling at a constant speed, an inclination angle adoption unit that employs the inclination angle of the second inclination angle calculation unit;
A signal generation unit that generates an optical axis control signal for controlling the optical axis of the headlight mounted on the vehicle using the inclination angle adopted by the inclination angle adoption unit; Control device.
The first tilt angle calculation unit calculates a tilt angle using the longitudinal acceleration at two time points detected by the acceleration sensor and the vertical acceleration at the two time points, and calculates one of the two time points. The headlight according to claim 1, wherein the longitudinal acceleration and the vertical acceleration when the vehicle is traveling at an equal acceleration are used as the longitudinal acceleration and the vertical acceleration at the time. Optical axis control device.
The vehicle state determination unit determines that the vehicle is traveling at a constant acceleration when the acceleration in the front-rear direction is other than zero and the angular velocity is zero during traveling of the vehicle. Item 3. An optical axis control device for a headlight according to Item 2.
The vehicle state determination unit determines that the vehicle is traveling at a constant speed when the acceleration in the front-rear direction is zero and the angular velocity is zero during traveling of the vehicle. 2. The optical axis control device for a headlight according to claim 1.
The vehicle state determination unit determines whether the accelerator opening of the vehicle has changed,
The inclination angle adoption unit employs the inclination angle of the first inclination angle calculation unit when the vehicle state determination unit determines that the vehicle is traveling at a constant speed and there is no change in the accelerator opening. The headlamp optical axis control device according to claim 1.
The vehicle state determination unit determines whether the accelerator opening of the vehicle has changed,
The signal generation unit, when the vehicle state determination unit determines that the vehicle is traveling at a constant speed and there is a change in the accelerator opening, maintains the optical axis control signal generated before the vehicle. Item 2. An optical axis control device for a headlight according to Item 1.
When the inclination angle of the first inclination angle calculation unit is adopted by the inclination angle adoption unit, a calibration unit that calibrates the inclination angle of the second inclination angle calculation unit using the adopted inclination angle is provided. The headlamp optical axis control device according to claim 1, wherein:
When a difference between the inclination angle of the first inclination angle calculation unit and the inclination angle of the second inclination angle calculation unit is larger than a predetermined threshold value, a calibration unit for calibrating the sensitivity of the angular velocity sensor is provided. The headlamp optical axis control device according to claim 1.