JPWO2020031255A1 - Optical axis controller for headlights - Google Patents

Abstract

The first inclination angle calculation unit (11) calculates the inclination angle (θg) with respect to the road surface of the vehicle using the acceleration detected by the acceleration sensor (1). The second inclination angle calculation unit (12) calculates the inclination angle (θω) with respect to the road surface of the vehicle by using the angular velocity detected by the angular velocity sensor (2). When the vehicle condition determination unit (13) determines that the vehicle is stopped or traveling at a constant speed, the inclination angle adoption unit (14) determines the inclination angle (θg) of the first inclination angle calculation unit (11). When the vehicle is used and the vehicle condition determination unit (13) determines that the vehicle is running but not running at a constant speed, the inclination angle (θω) of the second inclination angle calculation unit (12) is adopted. The signal generation unit (15) uses the inclination angle adopted by the inclination angle adoption unit (14) to generate an optical axis control signal for controlling the optical axis of the headlight.

Description

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

In-vehicle headlights have been required to have a bright light source so as to brighten the field of view to ensure a better field of view or to drive more comfortably. On the other hand, the bright light source of the headlight may be annoying 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 a history of devising a light distribution that does not dazzle from oncoming vehicles in parallel with devising a light source that illuminates the front brightly.

A typical light distribution for headlights is a light distribution for passing lights, and while illuminating the road surface below the line of sight of the driver of an oncoming vehicle, light is emitted above the line of sight. I prevented it from leaking and prevented dazzling. The upper and lower borders of light and dark are cut-off line.

In addition, even if the vehicle tilts forward (nose dive) or backward (squat) due to passengers getting on and off or loading and unloading luggage, the headlights are controlled so that the irradiation direction of the headlights always faces the same direction. It is performed by the optical axis control device for lights. Slow control is sufficient for the above-mentioned control corresponding to passengers getting on and off or loading and unloading luggage, and is also called static control. The behavior of the vehicle rotating around the left-right axis of the vehicle, such as the forward tilt and the backward tilt of the vehicle, is expressed as pitching.

By the way, as a light source for headlights, new light sources such as bright discharge lamps and LEDs (Light Emitting Diodes) are becoming more widespread than conventional incandescent lamps that heat tungsten filaments in red. The bright light source gives the driver a bright field of view, providing a better view or a more comfortable driving environment even at night. However, compared to incandescent lamps and the like, discharge lamps and LEDs and the like have a larger difference in brightness above and below the cut-off line. Therefore, when the vehicle is stopped or running smoothly, it is possible to illuminate the road surface below the eyes of the driver of the oncoming vehicle by controlling the irradiation direction of the headlights to be constant, which is a problem. However, the slow control cannot follow the backward tilt when the vehicle is accelerating, and the boundary between the bright and dark areas divided by the cut-off line moves to the front of the vehicle, causing the driver to know the vehicle. It may cause discomfort that makes the shaking of the car feel even greater.

Therefore, by swiftly controlling the irradiation direction of the headlights to always be in the same direction, the reaction to the passenger getting on and off or loading and unloading of luggage is faster, and the vehicle leans forward when decelerating or tilts backward when the vehicle accelerates. Corresponding controls have been proposed (see, eg, Patent Document 1). Rapid control of the irradiation direction is also referred to as dynamic control as opposed to the static control described above.

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

JP-A-2009-126268

In the conventional optical axis control device for headlights, in order to improve the control accuracy of the optical axis, an acceleration sensor is used in combination with an angular velocity sensor that can quickly detect the forward tilt and the backward tilt of the vehicle. However, the conventional optical axis control device for headlights uses the tilt angle of the vehicle based on the value of the angular velocity sensor and the tilt angle of the vehicle based on the value of the acceleration sensor properly according to the situation of the vehicle. There wasn't.

The present invention has been made to solve the above-mentioned problems, and by properly using an acceleration sensor and an angular velocity sensor having different characteristics, slow control of the optical axis and rapid control can be performed with high accuracy. With the goal.

The optical axis control device for a headlight according to the present invention calculates the inclination angle of the vehicle with respect to the road surface by using the acceleration in the front-rear direction and the acceleration in the vertical direction of the vehicle detected by the acceleration sensor mounted on the vehicle. 1 The tilt angle calculation unit, the second tilt angle calculation unit that calculates the tilt angle with respect to the road surface of the vehicle using the angular velocity when the vehicle rotates back and forth detected by the angular velocity sensor mounted on the vehicle, and the acceleration sensor When the vehicle condition determination unit that determines the vehicle condition and the vehicle condition determination unit determines that the vehicle is stopped or running at a constant velocity using the detected acceleration and the angular velocity detected by the angular velocity sensor, When the tilt angle of the first tilt angle calculation unit is adopted and the vehicle condition determination unit determines that the vehicle is running but not running at a constant velocity, the tilt angle of the second tilt angle calculation unit is adopted. It includes a adoption unit and a signal generation unit that generates an optical axis control signal for controlling the optical axis of a headlight mounted on a vehicle by using the inclination angle adopted by the inclination angle adoption unit.

According to the present invention, when the vehicle is stopped or traveling at a constant velocity, an inclination angle based on the value of the acceleration sensor is adopted, and when the vehicle is traveling but not traveling at a constant velocity, the value of the angular velocity sensor is used. Since the tilt angle based on the angle is adopted, the slow control and the rapid 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.

It is a block diagram which shows the structural example of the optical axis control device for a headlight which concerns on Embodiment 1. FIG. It is a figure explaining the acceleration and the inclination angle of a vehicle in Embodiment 1. It is a figure explaining the angular velocity and the inclination angle of a vehicle in Embodiment 1. FIG. It is a flowchart which shows the operation example of the optical axis control device for a headlight which concerns on Embodiment 1. FIG. It is a figure explaining the angle change of the stopped vehicle in Embodiment 1. It is a figure explaining the angle change of the vehicle running at a constant speed in Embodiment 1. It is a figure explaining the angle change of the vehicle at the time of traveling uphill in Embodiment 1. It is a figure explaining the angle change of the vehicle at the time of acceleration in Embodiment 1. It is a figure explaining the angle change of the vehicle while traveling in a recess in Embodiment 1. It is a block diagram which shows the structural example of the optical axis control device for a headlight which concerns on Embodiment 2. FIG. It is a flowchart which shows the operation example of the optical axis control device for a headlight which concerns on Embodiment 2. FIG. It is a flowchart which shows the modification of the operation of the optical axis control device for a headlight which concerns on Embodiment 2. FIG. 13A and 13B are diagrams showing a hardware configuration example of the optical axis control device 10 for headlights according to each embodiment.

Hereinafter, in order to explain the present invention in more detail, a mode for carrying out the present invention will be described with reference to the accompanying drawings.
Embodiment 1.
FIG. 1 is a block diagram showing a configuration example of the optical axis control device 10 for headlights according to the first embodiment. The optical axis control device 10 for headlights is mounted on a vehicle and controls the optical axis of the headlights. The optical axis control device 10 for headlights 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 the vehicle.

The acceleration sensor 1 detects the acceleration in the front-rear direction and the acceleration in the up-down direction of the vehicle, and outputs the detected acceleration to the headlight optical axis control device 10. The angular velocity sensor 2 detects the angular velocity when the vehicle rotates back and forth, and outputs the detected angular velocity to the optical axis control device 10 for the headlight. 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 control device 10. The accelerator opening sensor 4 detects the accelerator opening of the vehicle and outputs the detected accelerator opening to the headlight optical axis control device 10.

The optical axis control actuator 5 controls the angle of the optical axis of the headlight in response to the optical axis control signal output by the headlight optical axis control device 10. By operating the angle of the optical axis by the optical axis control actuator 5, the irradiation direction of the headlight is changed so as to cancel the change in the inclination angle of the vehicle. As a result, the optical axis of the headlight with respect to the road surface is kept constant even if the inclination angle of the vehicle changes.

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

The first inclination angle calculation unit 11 calculates the inclination angle θg with respect to the road surface of the vehicle by using the acceleration in the front-rear direction and the acceleration in the up-down direction 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 tilt angle calculation unit 11 calculates the tilt angle θg by, for example, the method described in International Publication No. 2016/189707. Hereinafter, a method for 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 with the front-rear direction of the vehicle as the X-axis and the vertical direction as the Z-axis is used, and the direction and magnitude of the acceleration applied to the vehicle are expressed by the position of the weight suspended from the spring. Further, if a planar quadrangle having four vertices at the center points of the front, rear, left, and right wheels touching the road surface is regarded as a virtual trolley, the plane of the virtual trolley is parallel to the road surface. Therefore, the angle θ formed by the virtual bogie and the vehicle body supported by the suspension on the bogie is the inclination angle of the vehicle with respect to the road surface. FIG. 2 shows the behavior of the weight as seen from the virtual bogie of the vehicle. In FIG. 2, the front-rear direction of the virtual trolley is the Xi axis, and the vertical direction is the Zi axis.

As the vehicle accelerates, as shown in FIG. 2, the weight moves parallel to the road surface on both horizontal and sloping roads. From a different point of view, the weight moves in the Xi axis direction of the virtual dolly. That is, the change in acceleration due to vehicle running is parallel to the road surface, that is, as shown by the arrow 20 in the Xi axis direction of the virtual dolly. On the other hand, the X-axis during vehicle acceleration is tilted at an angle θ with respect to the angle of the road surface. At that time, the behavior of the weight as seen from the acceleration measurement system mounted on the vehicle body moves ΔX in the X-axis direction and ΔZ in the Z-axis direction, so the inclination angle θg of the vehicle with respect to the road surface is expressed by the equation (1). To.

θg = tan ^-1 (ΔZ / ΔX) (1)

Therefore, in the acceleration measurement system mounted on the vehicle body, the amount of movement of the weight (arrow) that moves parallel to the road surface at two time points, the reference time point km before the vehicle accelerates and decelerates and the time point kn during acceleration and deceleration. 20) That is, by observing the difference in acceleration in the vertical direction (ΔZ) and the difference in acceleration in the front-rear direction (ΔX), it is possible to calculate the inclination angle θg with respect to the road surface of the vehicle regardless of the slope of the road on which the vehicle is traveling. it can.

The first tilt angle calculation unit 11 has the acceleration in the front-rear direction and the acceleration in the up-down direction at the reference time km, and the acceleration in the front-rear direction and the up-down direction detected by the acceleration sensor 1 when the vehicle is traveling at the same acceleration. It is desirable to use the acceleration of. By using the acceleration during constant acceleration running, the changing acceleration, that is, the difference in acceleration can be easily detected, so that a highly reliable inclination angle θg can be obtained. The vehicle state determination unit 13, which will be described later, determines whether or not the vehicle is traveling at a constant acceleration.
Further, the first inclination angle calculation unit 11 may output an average value or a median value obtained from a plurality of inclination angles θg to the inclination angle adoption unit 14. As a result, a more reliable tilt angle θg can be obtained.

The second inclination angle calculation unit 12 calculates the inclination angle θω with respect to the road surface of the vehicle by using the angular velocity when the vehicle rotates back and forth, that is, the angular velocity in the pitching angle direction, which is detected by the angular velocity sensor 2. 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 for explaining the angular velocity and the inclination angle of the vehicle in the first embodiment. FIG. 3 shows the sampling time of the angular velocity when the vehicle accelerates, the actual tilt angle of the vehicle, the angular velocity detected by the angular velocity sensor 2, and the integrated value of the angular velocity. When the sampling time is 0 [ms], the vehicle is stopped and the tilt angle of the vehicle is 0 [degrees]. Since the vehicle accelerates during the sampling time of 0 [ms] to 50 [ms] and the vehicle tilts backward due to the acceleration, the tilt 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 tilt angle of the vehicle is maintained at 1 [degree]. The vehicle travels at a constant speed during the sampling time of 100 [ms] to 150 [ms], and after 150 [ms], the tilt angle of the vehicle becomes 0 [degrees].

As shown in FIG. 3, the angular velocity sensor 2 detects an angular 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. In this way, since the second tilt angle calculation unit 12 can obtain the tilt angle θω for each sampling time, the forward tilt and the backward tilt of the vehicle can be detected more quickly than the first tilt angle calculation unit 11. Can be done.

The vehicle state determination unit 13 determines the state of the vehicle by using the 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 stopped, running, constant velocity running, or constant acceleration running. 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 by using, for example, the vehicle speed detected by the vehicle speed sensor 3. Further, when the vehicle is traveling, the acceleration in the front-rear direction 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. Is determined to be traveling at a constant acceleration. Further, in the vehicle state determination unit 13, when the acceleration in the front-rear direction detected by the acceleration sensor 1 is zero and the angular velocity detected by the angular velocity sensor 2 is also zero while the vehicle is running, the vehicle has a constant velocity. Judge that it is running.

The inclination angle adoption unit 14 receives an inclination angle θg from the first inclination angle calculation unit 11, an inclination angle θω from the second inclination angle calculation unit 12, and a determination result from the vehicle state determination unit 13. When the vehicle condition determination unit 13 determines that the vehicle is stopped or traveling at a constant speed, the inclination angle adoption unit 14 adopts the inclination angle θg of the first inclination angle calculation unit 11 and adopts the inclination angle θg. Is output to the signal generation unit 15. On the other hand, when the vehicle condition determination unit 13 determines that the vehicle is running but not running at a constant speed, the inclination angle adoption unit 14 adopts and adopts the inclination angle θω of the second inclination angle calculation unit 12. The inclination angle θω is output to the signal generation unit 15. When the vehicle condition determination unit 13 determines that there is a change in the accelerator opening of the vehicle while traveling at a constant speed, the inclination angle adoption unit 14 does not adopt the inclination angles θg and θω and outputs the signal to the signal generation unit 15. do not do.

The signal generation unit 15 uses the inclination angle θg or the inclination angle θω adopted by the inclination angle adoption unit 14, and is used to rotate the optical axis of the headlight in the direction opposite to the inclination angle θg or the inclination angle θω. Generates 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 is provided with the optical axis of the headlight so as to prevent dazzling of the driver of an oncoming vehicle or the like. Let it be controlled.

Next, the operation of the optical axis control device 10 for headlights according to the first embodiment will be described.
FIG. 4 is a flowchart showing an operation example of the optical axis control device 10 for headlights according to the first embodiment. The optical axis control device 10 for headlights repeats the flowchart 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 tilt angle calculation unit 12 calculates the tilt 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 (step ST14 “YES”), in step ST15, the inclination angle adoption unit 14 adopts 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 it to the optical axis control actuator 5. A specific example will be described with reference to FIG. 5 described later.

When the vehicle state determination unit 13 determines that the vehicle is running (step ST14 “NO”) and determines that the vehicle is not running at a constant speed (step ST17 “NO”), in step ST18, The tilt angle adopting unit 14 adopts the tilt angle θω of the second tilt angle calculation unit 12. After that, 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 it to the optical axis control actuator 5. Specific examples will be described with reference to FIGS. 8 and 9 described later.

When the vehicle condition determination unit 13 determines that the vehicle is traveling at a constant speed (step ST17 “YES”) and determines that the accelerator opening has changed (step ST19 “YES”), the vehicle is on a slope. The optical axis control device 10 for the headlight keeps the optical axis of the headlight unchanged. That is, the signal generation unit 15 maintains the optical axis control signal generated immediately before (for example, when the operation shown in the flowchart of FIG. 4 was executed last time). A specific example will be described with reference to FIG. 7 described later.

When the vehicle state determination unit 13 determines that the vehicle is traveling at a constant speed (step ST17 “YES”) and determines that the accelerator opening does not change (step ST19 “NO”), in step ST15. The tilt angle adopting unit 14 adopts the tilt angle θg of the first tilt 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 it to the optical axis control actuator 5. A specific example will be described with reference to FIG. 6 described later.

Next, a specific example of optical axis control of the optical axis control device 10 for headlights will be described with reference to FIGS. 5 to 9. Note that, in FIGS. 5 to 9, for convenience, values such as the detection value of each sensor and the tilt angle of the vehicle are described, but these values are reference values and are different from the 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 changes as the luggage is loaded and unloaded at the rear part of the stopped vehicle.
When the vehicle state determination unit 13 determines that the vehicle is stopped, the optical axis control may be slow because the vehicle is in a static state. Therefore, the tilt angle adopting unit 14 adopts the tilt angle θg, which is based on the acceleration sensor 1 calculated by the first tilt angle calculation unit 11, and has low responsiveness but high reliability. The signal generation unit 15 generates an optical axis control signal for controlling in the direction of lowering the optical axis when the inclination angle θg is increased, that is, when the front of the vehicle is directed upward. On the other hand, the signal generation unit 15 generates an optical axis control signal for controlling in the direction of raising the optical axis when the inclination angle θg is lowered, that is, when the front of the vehicle is directed downward.

FIG. 6 is a diagram illustrating a change in the angle of the vehicle during constant speed traveling in the first embodiment. When the vehicle state determination unit 13 determines that the vehicle is traveling at a constant speed, the vehicle state determination unit 13 subsequently confirms a change in the accelerator opening degree. When the vehicle condition determination unit 13 determines that the vehicle is traveling at a constant speed and there is no change in the accelerator opening, it is presumed that the angle of the road surface on which the vehicle is traveling at a constant speed has not changed. To. It is presumed that the vehicle is in a static state because the tilt angle change (that is, sway) of the vehicle does not occur due to acceleration / deceleration in the constant speed traveling state where the road surface angle does not change. Therefore, the tilt angle adopting unit 14 adopts the tilt angle θg based on the acceleration sensor 1 calculated by the first tilt angle calculation unit 11.

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.
When the road surface angle changes while the vehicle is traveling at a constant speed, the headlight optical axis control device 10 may erroneously detect the change in the road surface angle as a change in the inclination angle of the vehicle. For example, when the road changes from a flat road to an uphill during traveling at a constant speed, the headlight optical axis control device 10 may determine that the front of the vehicle has turned upward and 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 degree. In order for the road surface on which the vehicle is running to change from a flat road to an uphill road and to maintain constant speed driving, the driver must step on the accelerator strongly. In FIG. 7, the case where the accelerator is strongly depressed is represented as “(+ α)”. On the contrary, in order to change the road surface on which the vehicle is traveling from a flat road to a downhill and to maintain constant speed driving, it is necessary for the driver to weaken the depression of the accelerator. Such an accelerator operation is also 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 degree changes while the vehicle is traveling at a constant speed is the case where the road surface angle changes. Therefore, when the vehicle state determination unit 13 determines that the vehicle is traveling at a constant speed and there is a change in the accelerator opening degree, the inclination angle adoption unit 14 does not adopt any of the inclination angles θg and θω. , The signal generation unit 15 does not control the optical axis. On the other hand, while the vehicle is traveling on a slope at a constant speed and there is no change in the accelerator opening, the inclination angle adoption unit 14 uses the inclination angle based on the acceleration sensor 1 calculated by the first inclination angle calculation unit 11. θg is adopted.

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 sways due to acceleration / deceleration, and the inclination angle changes. That is, when the accelerator opening of the vehicle changes and the vehicle speed changes accordingly, it is presumed that the vehicle is swaying due to acceleration / deceleration. When the vehicle is running and swinging, the method of calculating the tilt angle θg using the accelerations at two time points is not suitable because the response of the tilt angle θg to the swing is low. Therefore, when the vehicle state determination unit 13 determines that the vehicle is running and swaying, the inclination angle adoption unit 14 has a responsiveness based on the angular velocity sensor 2 calculated by the second inclination angle calculation unit 12. Adopt a high tilt angle θω.

FIG. 9 is a diagram illustrating a change in the angle of the vehicle while traveling in the recess in the first embodiment. When a vehicle traveling at a constant speed travels on a concave or convex portion of a road surface, the change in the inclination angle θω calculated using the angular velocity coincides with the appropriate optical axis control direction. For example, when the front wheel of the vehicle travels in the recess as shown in FIG. 9, the front of the vehicle moves from the bottom to the top, 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 it. In this way, while the vehicle is swaying by traveling in the concave portion or the convex portion, the inclination angle adoption unit 14 has high responsiveness based on the angular velocity sensor 2 calculated by the second inclination angle calculation unit 12. The tilt angle θω is adopted.

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

Further, the first tilt angle calculation unit 11 of the first embodiment tilts using the acceleration in the front-rear direction of km and kn at two time points and the vertical acceleration of km and kn at two time points detected by the acceleration sensor 1. Calculate the angle θg. Then, the first inclination angle calculation unit 11 determines the acceleration in the front-rear direction and the acceleration in the up-down direction at one of the two time points km and kn in the front-rear direction when the vehicle is traveling at the same acceleration. Acceleration and vertical acceleration are used. As a result, the first inclination angle calculation unit 11 can accurately calculate the inclination angle θg of the stationary vehicle that is not in motion.

Further, the vehicle state determination unit 13 of the first embodiment 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 while the vehicle is traveling. As a result, the vehicle state determination unit 13 can determine more accurately than the case of determining whether or not the vehicle is traveling at a constant acceleration using the vehicle speed.

Further, the vehicle state determination unit 13 of the first embodiment 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 while the vehicle is traveling. As a result, the vehicle state determination unit 13 can make a determination with higher accuracy than when determining whether or not the vehicle is traveling at a constant speed using the vehicle speed.

Further, the vehicle state determination unit 13 of the first embodiment determines whether or not there is a change in the accelerator opening degree of the vehicle. The inclination angle adoption unit 14 adopts 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 degree. As a result, the headlight optical axis control device 10 can perform highly accurate optical axis control based on the highly reliable acceleration sensor 1 when the vehicle is in a static state.

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

Embodiment 2.
FIG. 10 is a block diagram showing an optical axis control device 10 for a headlight according to a 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. .. In FIG. 10, the same or corresponding parts as those in FIG. 1 are designated by the same reference numerals, and the 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, the calibration method shown in FIG. 11 and the calibration method shown in FIG. 12, will be illustrated.

FIG. 11 is a flowchart showing an operation example of the optical axis control device 10 for headlights 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 tilt angle θω may deviate from the actual tilt angle of the vehicle when used for a long time due to the property of integrating the angular velocities for each sampling time. Therefore, it is desirable to calibrate the tilt angle θω. Therefore, when the tilt angle adopting unit 14 adopts a highly reliable tilt angle θg based on the acceleration sensor 1 (step ST15), in step ST21, the calibration unit 14a uses the tilt angle of the second tilt angle calculation unit 12. The tilt angle θω is calibrated by overwriting the tilt angle θg of the first tilt angle calculation unit 11 on θω. After that, the second tilt angle calculation unit 12 integrates the angular velocities detected by the angular velocity sensor 2 with respect to the tilt angle θω after calibration to obtain the tilt angle θω.

FIG. 12 is a flowchart showing a modified example of the operation of the optical axis control device 10 for headlights 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 FIGS. 4 and 11.
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 tilt angle θω in step ST21 of FIG. 11, an error of the same tendency occurs again in the tilt angle θω. .. Therefore, in the calibration unit 14a, 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 the predetermined threshold value θth (step ST22 “YES”). , In step ST23, the sensitivity of the angular velocity sensor 2 is calibrated. On the other hand, the calibration unit 14a has an 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 equal to or less than the threshold value θth (step ST22 “NO”). 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 by the tilt angle θg in step ST21, that is, before calibration.

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

θg = kθω + θo (2)

Note that FIG. 12 shows an example in which the calibration unit 14a executes an operation of calibrating the inclination angle θω (step ST21) and an operation of calibrating the sensitivity of the angular velocity sensor 2 (step ST22 and step 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 a calibration unit 14a. When the tilt angle θg of the first tilt angle calculation unit 11 is adopted by the tilt angle adoption unit 14, the calibration unit 14a calibrates the tilt angle θω of the second tilt angle calculation unit 12 using the adopted tilt angle θg. To do. As a result, the headlight optical axis control device 10 can perform highly accurate optical axis control using the angular velocity sensor 2.

Further, the calibration unit 14a of the second embodiment has an 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. As a result, the headlight optical axis control device 10 can perform highly accurate optical axis control using the angular velocity sensor 2.

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

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

As shown in FIG. 13B, when the processing circuit is the processor 101, the first tilt angle calculation unit 11, the second tilt angle calculation unit 12, the vehicle state determination unit 13, the tilt 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. The software or firmware is described as a program and stored in the memory 102. The processor 101 realizes the functions of each part by reading and executing the program stored in the memory 102. That is, the headlight optical axis control device 10 stores a program in which the steps shown in the flowcharts of FIGS. 4, 11 and 12 are eventually executed when executed by the processor 101. A memory 102 for the purpose is provided. In addition, this program provides a computer with the procedures or methods of the first tilt angle calculation unit 11, the second tilt angle calculation unit 12, the vehicle condition determination unit 13, the tilt 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 unit, a microprocessor, or the like.
The memory 102 may be a non-volatile 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 may be a non-volatile or volatile semiconductor memory such as a hard disk or a flexible disk. It may be a magnetic disk of the above, or an optical disk such as a CD (Compact Disc) or a DVD (Digital Versaille Disc).

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

Within the scope of the invention, the present invention allows any combination of embodiments, modifications of any component of each embodiment, or omission of any component of each embodiment.

In the headlight optical axis control device according to the present invention, the value of the acceleration sensor and the value of the angular velocity sensor are used properly according to the state of the vehicle, so that the optical axis of the headlight is statically controlled and dynamically controlled. It is suitable for use in optical axis control devices for headlights.

1 Acceleration sensor, 2 Angular velocity sensor, 3 Vehicle speed sensor, 4 Accelerator opening sensor, 5 Optical axis control actuator, 10 Optical axis control device for headlight, 11 1st tilt angle calculation unit, 12 2nd tilt angle calculation unit, 13 Vehicle condition determination unit, 14 tilt angle adoption unit, 14a calibration unit, 15 signal generation unit, 100 processing circuit, 101 processor, 102 memory.

Claims (8)

A first inclination angle calculation unit that calculates an inclination angle with respect to the road surface of the vehicle by using the acceleration in the front-rear direction and the acceleration in the up-down direction of the vehicle detected by an acceleration sensor mounted on the vehicle.
A second tilt angle calculation unit that calculates the tilt angle of the vehicle with respect to the road surface using the angular velocity when the vehicle rotates back and forth detected by the 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 condition determination unit determines that the vehicle is stopped or traveling at a constant speed, the inclination angle of the first inclination angle calculation unit is adopted, and the vehicle condition determination unit determines that the vehicle is traveling. If it is determined that the vehicle is not running at a constant speed, the tilt angle adopting unit that adopts the tilt angle of the second tilt angle calculation unit and the tilt angle adopting unit
An optical axis for a headlight including a signal generation unit that generates an optical axis control signal for controlling the optical axis of the headlight mounted on the vehicle by using the inclination angle adopted by the inclination angle adoption unit. Control device. The first tilt angle calculation unit calculates the tilt angle using the acceleration in the front-rear direction at two time points and the acceleration in the vertical direction at the two time points detected by the acceleration sensor, and one of the two time points. The headlight according to claim 1, wherein the acceleration in the front-rear direction and the acceleration in the up-down direction when the vehicle is traveling at a constant acceleration are used as the acceleration in the front-rear direction and the acceleration in the up-down direction at a time point. Optical axis control device. A claim characterized in that 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 while the vehicle is traveling. Item 2. The optical axis control device for headlights according to item 2. The vehicle condition determination unit is characterized in that, when the acceleration in the front-rear direction is zero and the angular velocity is zero while the vehicle is traveling, it is determined that the vehicle is traveling at a constant speed. 1. The optical axis control device for a headlight according to 1. The vehicle state determination unit determines whether or not there is a change in the accelerator opening of the vehicle.
The tilt angle adopting unit is characterized by adopting the tilt angle of the first tilt 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 optical axis control device for a headlight according to claim 1. The vehicle state determination unit determines whether or not there is a change in the accelerator opening of the vehicle.
The claim is characterized in that 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 degree, the signal generation unit maintains an optical axis control signal generated before that. Item 1. The 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 for calibrating the inclination angle of the second inclination angle calculation unit using the adopted inclination angle is provided. The optical axis control device for a headlight according to claim 1. When the difference between the tilt angle of the first tilt angle calculation unit and the tilt angle of the second tilt 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 optical axis control device for a headlight according to claim 1.

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