JP2014088156A - Headlamp optical axis control unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To optimally control an optical axis all the time irrespective of the state of a vehicle (whether a vehicle is running or stopped) and the condition of a road surface (whether a road surface is even or irregular, or is a slope).SOLUTION: A vehicle state decision unit 204 decides whether a vehicle is stopped or running, and a switching unit 201 switches a first control signal production unit 202 and second control signal production unit 203. When the vehicle is stopped, the first control signal production unit 202 calculates a magnitude of a relative angle change of the vehicle, which depends on whether an occupant rides or alights or a load is taken out or put in, on the basis of an inclination angle measured by an inclination angle measuring unit 100. When the vehicle is running, the second control signal production unit 203 calculates the relative inclination angle of the vehicle with respect to a road surface on the basis of the inclination angle measured by the inclination angle measuring unit 100. An optical axis control unit 300 controls the optical axis of each of headlamps according to the calculated inclination angle, and keeps a certain angle with respect to the road surface.

Description

  The present invention relates to an optical axis control device for a headlamp that detects an inclination angle of a vehicle body and controls an optical axis of a headlamp that illuminates the front of the vehicle.

  The headlamp mounted on the vehicle forms a light distribution for passing (passing light, low beam) so as not to dazzle the driver of the oncoming vehicle. The optical axis at the time of forming the light distribution for passing each other is, for example, relative to the road surface so as not to dazzle the driver of the oncoming vehicle even if a plurality of passengers get on or heavy loads are loaded. It is desirable to always maintain a constant angle. Conventionally, in order to keep the optical axis of the headlamp at a desired angle, a headlamp optical axis control device (odd levelizer) is mounted on the vehicle.

  For example, in the conventional headlight optical axis control device described in Patent Document 1, an acceleration sensor is installed to measure the longitudinal acceleration of the vehicle, and the acceleration is measured to measure the longitudinal acceleration of the chassis. Install the sensor. While the vehicle is stopped, the relative inclination angle with respect to the road surface of the vehicle is calculated using the outputs of the two acceleration sensors and the gravitational acceleration, and the optical axis is controlled based on the calculated relative inclination angle.

  In the conventional headlight optical axis control device described in Patent Document 2, two distance sensors are installed in the vehicle front-rear direction for sensing two sensors by reflecting ultrasonic waves or light (laser) on the road surface. To measure the vehicle height from the vehicle to the road, calculate the relative inclination angle with respect to the road surface of the vehicle from the measured vehicle height and the installation interval of the two distance sensors, and control the optical axis based on the calculated relative inclination angle .

  In the conventional headlight optical axis control device described in Patent Document 3, the radio wave transmitted from the transmitting antenna is reflected on the road surface, and the relative inclination angle with respect to the road surface of the vehicle is calculated from the signals received by the two receiving antennas. The optical axis is controlled based on the calculated relative tilt angle.

JP 2010-247551 A JP 2003-127757 A JP-A-2005-189101

Since the optical axis control device for headlamps described in Patent Document 1 measures the relative inclination angle using gravitational acceleration, the acceleration during vehicle acceleration / deceleration becomes a measurement error. For this reason, the relative inclination angle can be accurately detected only when the vehicle is stopped, and there is a problem that an erroneous optical axis control is performed while the vehicle is traveling.
In addition, even when the vehicle is stopped, for example, when the vehicle is tilted, such as a state where the tire rides on a curb, and the vehicle is tilted, there is a problem that the correct relative tilt angle cannot be calculated and erroneous optical axis control is performed. .

Moreover, since the optical axis control device for headlamps described in Patent Document 2 measures vehicle height using ultrasonic waves or light (laser), a distance measurement error occurs due to road irregularities. Therefore, in order to eliminate the influence of the unevenness of the road surface, the inclination angle is measured at a plurality of locations while traveling, and the relative inclination angle with respect to the road surface of the vehicle is detected from the measured plurality of inclination angles. On the other hand, since the tilt angle cannot be measured at a plurality of locations while the vehicle is stopped, the relative tilt angle cannot be detected with high accuracy, and there has been a problem of erroneous optical axis control.
Furthermore, if the optical axis control is not performed while the vehicle is stopped, there is a problem that it is not possible to appropriately cope with a change in the optical axis associated with a change in the vehicle inclination due to passengers getting on and off or loading and unloading.

In addition, the headlamp optical axis control device described in Patent Document 3 can detect the relative inclination angle with high accuracy only while the vehicle is running, as in Patent Document 2. Therefore, there has been a problem that the relative tilt angle cannot be detected with high accuracy while the vehicle is stopped, and erroneous optical axis control is performed.
Furthermore, if the optical axis control is not performed while the vehicle is stopped, there is a problem that it is not possible to appropriately cope with a change in the optical axis associated with a change in the vehicle inclination due to passengers getting on and off or loading and unloading.

  Moreover, in the said patent documents 1-3, when it cannot respond appropriately to an optical axis change, the subject that the light of a headlamp will dazzle the driver of an oncoming vehicle occurs.

  That is, conventionally, when a sensor that measures the tilt angle of a vehicle without contact is used, the relative tilt angle with respect to the road surface of the vehicle can be measured only while the vehicle is running or stopped, and is always optimal. There was a problem that the optical axis could not be controlled.

  Conventionally, when a sensor that measures the tilt angle of a vehicle without contact is used, the relative tilt angle with respect to the road surface of the vehicle cannot be measured due to road surface unevenness and road surface conditions such as slopes, and optimal optical axis control is possible. There was a problem that it was not possible.

  The present invention has been made to solve the above-described problems, and is always optimal regardless of the state of the vehicle (running or stopped) and the state of the road surface (flat, uneven, slope, etc.). The purpose is to perform an optical axis control.

  An optical axis control device for a headlamp according to the present invention includes a tilt angle measurement unit that measures a tilt angle of a vehicle, and a relative angle change amount of the tilt angle measured by the tilt angle measurement unit. A relative inclination angle of the vehicle with respect to the road surface is calculated from the inclination angle measured by the first control signal generation unit that generates a first control signal for controlling the axis to a predetermined angle and the inclination angle measurement unit, and the relative Based on a second control signal generating unit that generates a second control signal for controlling the optical axis of the headlamp to a predetermined angle from a specific inclination angle, and the first control signal when the vehicle is stopped When the vehicle is traveling, an optical axis control unit that controls the optical axis of the headlamp is provided based on the second control signal.

  According to this invention, when the vehicle is stopped, the optical axis control is performed based on the angle change amount according to the passenger getting on and off or loading / unloading, and the optical axis control is performed based on the inclination angle with respect to the road surface of the vehicle. Therefore, optimum optical axis control can always be performed regardless of the state of the vehicle (running or stopped) and the state of the road surface (flat, uneven, slope, etc.).

It is a block diagram which shows the structure of the optical-axis control apparatus for headlamps which concerns on Embodiment 1 of this invention. It is a figure which shows an example of the vehicle carrying the optical-axis control apparatus for headlamps which concerns on Embodiment 1. FIG. 6 is a diagram for explaining a specific example of the operation of the optical axis control device for headlamps according to Embodiment 1. FIG. It is a block diagram which shows the structure of the inclination sensor of the radio wave system with which the optical axis control apparatus for headlamps which concerns on Embodiment 1 is provided. It is a figure explaining the inclination angle measured using the electromagnetic wave type inclination sensor shown in FIG. It is a block diagram which shows the structure of the inclination sensor of the ultrasonic system with which the optical axis control apparatus for headlamps concerning Embodiment 2 of this invention is provided. It is a figure explaining the inclination angle measured using the ultrasonic type inclination sensor shown in FIG. It is a block diagram which shows the structure of the inclination sensor of the acceleration system with which the optical-axis control apparatus for headlamps concerning Embodiment 3 of this invention is provided. It is a figure explaining the inclination angle measured using the acceleration type inclination sensor shown in FIG.

Embodiment 1 FIG.
FIG. 1 is a block diagram showing a configuration of a headlamp optical axis control device 1 according to Embodiment 1 of the present invention. As shown in FIG. 1, the headlamp optical axis control device 1 includes an inclination angle measurement unit 100, a control signal generation unit 200, and an optical axis control unit 300.

  FIG. 2 is an example of a vehicle 2 on which the headlamp optical axis control device 1 according to the first embodiment is mounted. The vehicle 2 includes a vehicle body 3 and a chassis 4, and the vehicle body 3 is supported via suspensions and tires of the chassis 4. A headlamp optical axis control device 1 and a headlamp 5 are attached to the vehicle body 3. The headlamp optical axis control device 1 controls the optical axis of the headlamp 5 so as to maintain a predetermined angle with respect to the road surface regardless of the inclination state of the vehicle 2.

  In FIG. 1, an inclination angle measuring unit 100 includes an inclination sensor 101 that measures an inclination angle of a vehicle body 3 with respect to a road surface. Details will be described later.

  The control signal generation unit 200 generates a first control signal based on the displacement amount of the inclination angle measured by the inclination angle measurement unit 100 (relative angle change amount of the inclination angle). 202, a second control signal generation unit 203 that calculates a tilt angle of the vehicle body 3 with respect to the road surface (hereinafter referred to as a relative tilt angle) from the tilt angle measured by the tilt angle measurement unit 100, and generates a second control signal; The vehicle state determination unit 204 that determines the state of the vehicle, and the switching unit 201 that switches between the first control signal generation unit 202 and the second control signal generation unit 203 according to the vehicle state. The vehicle state determination unit 204 is composed of, for example, a speed sensor.

  Here, the relative inclination angle φ (t1) of the vehicle body 3 with respect to the road surface at time t1 and the relative inclination angle φ (t2) of the vehicle body 3 with respect to the road surface at time t2 (where t1 <t2) The angular deviation Δφ is expressed by the following equation (1).

Δφ = φ (t2) −φ (t1) (1)

  The optical axis control unit 300 includes an optical axis control mechanism 302 that adjusts the angle of the optical axis of the headlamp 5 installed in the vehicle body 3, and a mechanism drive unit 301 that controls the driving of the optical axis control mechanism 302. . The optical axis control mechanism 302 is configured by an actuator, for example.

Next, the operation of the headlight optical axis control device 1 will be described.
The tilt sensor 101 in the tilt angle measuring unit 100 measures the tilt angle of the vehicle body 3 with respect to the local road surface, and outputs it to the control signal generating unit 200 as the tilt angle θ. Here, the inclination angle measured at time tn is represented as θ (tn).

  The vehicle state determination unit 204 in the control signal generation unit 200 determines whether the vehicle 2 is running or stopped based on the vehicle speed measured by the speed sensor, and outputs a vehicle state determination signal to the switching unit 201. Note that the vehicle state determination unit 204 may have a speed sensor, or the vehicle state determination unit 204 may acquire a detection value of a speed sensor installed in the vehicle 2 in advance.

  Based on the vehicle state determination signal output from the vehicle state determination unit 204, the switching unit 201 uses the first control signal generation unit 202 when the vehicle is stopped and the second control signal generation unit 203 when the vehicle is traveling. The inclination angle θ measured by the inclination sensor 101 is output to the selected one.

  When the switching unit 201 selects the first control signal generation unit 202, that is, when the vehicle 2 is stopped, the first control signal generation unit 202 is based on the inclination angle measured by the inclination angle measurement unit 100. Then, the deviation amount Δφ of the tilt angle is calculated.

  The first control signal generation unit 202 holds the inclination angle θ (ta) measured immediately after the vehicle 2 stops, and when the inclination of the vehicle body 3 changes due to passengers getting on and off, loading / unloading, etc. A change in the tilt angle is detected, and the tilt angle θ (tb) at that time is held. Then, the first control signal generation unit 202 calculates the following equation (2) to obtain the tilt angle deviation amount Δφ.

Δφ = θ (tb) −θ (ta) (2)

Subsequently, the first control signal generation unit 202 generates a first control signal so as to correct the optical axis of the headlamp 5 by an angle corresponding to the calculated deviation amount Δφ, and the optical axis control unit 300. Output to.
For example, if the optical axis control angle at the time ta is A (ta), the optical axis control angle A (tb) after the time tb is expressed by the following equation (3). The first control signal generation unit 202 outputs A (tb) obtained from Expression (3) to the optical axis control unit 300 as the first control signal. Thereby, the first control signal of the optical axis control angle is obtained such that the optical axis of the headlamp 5 is always in a predetermined inclined state (inclined state immediately before stopping) with respect to the road surface.

A (tb) = A (ta) −Δφ (3)
Here, A (ta) is an optical axis control angle used for optical axis control by the mechanism drive unit 301 at time ta, and is acquired from the mechanism drive unit 301 by the first control signal generation unit 202.

  When the vehicle body 3 is tilted again due to passengers getting on and off, loading and unloading, etc. while the vehicle is stopped, the first control signal generator 202 detects the change in the tilt angle, and the tilt angle at that time is detected. θ (tb1) (where tb <tb1) is held, Δφ = θ (tb1) −θ (ta) and A (tb1) = A (ta) −Δφ are calculated, and the first control signal A ( What is necessary is just to obtain | require tb1). Alternatively, Δφ = θ (tb1) −θ (tb) may be calculated.

On the other hand, when the switching unit 201 selects the second control signal generation unit 203, that is, when the vehicle 2 is traveling, the second control signal generation unit 203 determines the inclination angle θ (tc) measured by the inclination sensor 101. ) Is calculated, a relative inclination angle φ (tc) with respect to the road surface of the vehicle body 3 whose inclination angle has changed due to passengers getting on and off, loading and unloading, etc. is calculated. Here, in order to suppress the influence of local unevenness on the road surface, for example, the inclination angles θ (tc) and θ (tc-1) of the past three points (tc, tc-1, tc-2) including the time tc are included. , Θ (tc−2), the relative inclination angle φ (tc) is expressed by the following equation (4).
Note that statistical processing for unevenness suppression is not limited to moving average processing.

φ (tc) = {(θ (tc) + θ (tc-1) + θ (tc-2)) / 3 (4)

Subsequently, the second control signal generation unit 203 corrects the optical axis of the headlamp 5 by an angle corresponding to the calculated relative inclination angle φ (tc) so that the set value of the optical axis with respect to the road surface becomes A0. In addition, a second control signal is generated and output to the optical axis controller 300.
For example, assuming that the relative inclination angle φ (tc) of the vehicle body 3 with respect to the road surface at time tc, the second control signal generation unit 203 maintains the angle of the optical axis of the headlamp 5 at a predetermined set value A0. Therefore, the optical axis control angle A (tc) is calculated from the following equation (5), and A (tc) is output to the optical axis control unit 300 as the second control signal. Thereby, the second control signal of the optical axis control angle is obtained such that the optical axis of the headlamp 5 is always in a predetermined inclination state (inclination state of the set value A0) with respect to the road surface.

A (tc) = A0−φ (tc) (5)

  The mechanism drive unit 301 in the optical axis control unit 300 outputs the first control signal output from the first control signal generation unit 202 while the vehicle is stopped, or the second control signal generation unit 203 while the vehicle is traveling. The optical axis control mechanism 302 is driven in accordance with the second control signal. The optical axis control mechanism 302 changes the angle of the optical axis of the headlamp 5.

  In the above description, the vehicle state determination unit 204 determines the travel and stop of the vehicle 2 based on the speed measured by the vehicle speed sensor. In addition to this, for example, the time of the tilt angle measured by the tilt angle measurement unit 100 You may determine the driving | running | working and stop of the vehicle 2 by determining threshold value for a fluctuation | variation. That is, the time fluctuation width of the inclination angle θ is small when the vehicle 2 is stopped, and the time fluctuation width of the inclination angle θ is large when the vehicle 2 is traveling due to the shaking of the vehicle body 3 and the unevenness of the road surface. The vehicle state determination unit 204 determines that the vehicle is stopped when the time fluctuation range of the inclination angle θ is equal to or smaller than a predetermined threshold value, and determines that the vehicle is traveling when larger than the threshold value.

Next, a specific example of the operation of the headlamp optical axis control device 1 will be described with reference to FIG.
3A shows the determination result of running / stop of the vehicle state determination unit 204, FIG. 3B shows the presence / absence of a load on the vehicle 2, and FIG. 3C shows the output of the tilt sensor 101. FIG. 3 (d) shows the leaning state of the vehicle body 3, which is the calculation result of the first control signal generator 202 and the second control signal generator 203, and FIG. 3 (e) shows the first control signal generation. The first and second control signals output from the unit 202 and the second control signal generation unit 203 are shown.

Here, as shown in FIGS. 3 (a) and 3 (b), the traveling vehicle 2 stopped at time t0, loaded with luggage at time t1, and resumed traveling at time t3. The case is shown as an example.
Until the vehicle 2 stops at time t 0, the switching unit 201 selects the second control signal generation unit 203 according to the determination result of the vehicle state determination unit 204, and the second control signal generation unit 203 measures the inclination sensor 101. The relative tilt angle φ1 is calculated from the tilt angle θ, and the optical axis control unit 300 controls the optical axis of the headlamp 5 according to the second control signal based on the relative tilt angle φ1.

  Immediately after the vehicle 2 stops at time t0, the switching unit 201 selects the first control signal generation unit 202 according to the determination result of the vehicle state determination unit 204, and the first control signal generation unit 202 measures the inclination sensor 101. The inclination angle θ (t0) is maintained.

At time t1, the vehicle body 3 vibrates due to load loading, and the tilt angle θ measured by the tilt sensor 101 changes before and after time t1.
The first control signal generation unit 202 monitors the tilt angle θ, and when the tilt angle θ stabilizes over a predetermined time after the tilt angle θ fluctuates before and after time t1, the tilt angle of the vehicle 2 changes at time t2. It is determined that the tilt angle θ (t2) at this time is held. Subsequently, the first control signal generation unit 202 calculates a tilt angle deviation amount Δφ = θ (t2) −θ (t1), generates a first control signal, and the optical axis control unit 300 outputs the first control signal. The optical axis of the headlamp 5 is controlled according to the control signal 1.

  When the luggage is loaded on the rear part of the vehicle 2, the rear of the vehicle body 3 is lowered to the road surface side and the front of the vehicle body 3 is raised, so that the optical axis of the headlamp 5 is directed upward. At this time, the optical axis control unit 300 adjusts the optical axis of the headlamp 5 downward based on the deviation amount Δφ of the upward inclination angle, so that the optical axis is maintained at a predetermined angle with respect to the road surface. .

When the vehicle 2 resumes traveling at time t3, the switching unit 201 selects the second control signal generation unit 203 according to the determination result of the vehicle state determination unit 204, and the second control signal generation unit 203 measures the inclination sensor 101. The relative tilt angle φ2 is calculated from the tilt angle θ, and the optical axis control unit 300 controls the optical axis of the headlamp 5 according to the second control signal based on the relative tilt angle φ2.
Here, the relationship of φ2 = φ1 + Δφ is established.

  Since time t3, since the vehicle 2 has gone up the slope, the vehicle slopes so that the front of the vehicle body 3 is further raised and the rear of the vehicle body 3 is further lowered to the road surface side due to the road surface gradient of the slope. Therefore, the relative inclination angle φ2 calculated by the second control signal generation unit 203 changes at time t4, and the optical axis of the headlamp 5 is adjusted downward accordingly. Therefore, even when the road surface is a slope, the optical axis is maintained at a predetermined angle with respect to the road surface.

  In FIG. 3, the control method from the running state has been described, but a preset optical axis control angle is used as the control method from the stopped state. The optical axis control is started, for example, by using the optical axis control angle obtained by traveling last before stopping. In particular, when the engine is started from a stopped state and travels, the second control signal generator 203 cannot perform the moving average processing of the tilt angle. It is effective to use the optical axis control angle calculated before turning off.

Next, an example in which the tilt sensor 101 of the headlamp optical axis control device 1 is configured by a radio wave type tilt sensor 101a will be described.
FIG. 4 is a block diagram showing the configuration of the radio wave type tilt sensor 101a. The radio wave type tilt sensor 101a includes one transmitting antenna 401, two receiving antennas 402 and 403, a transmitting unit 404, a receiving unit 405, a propagation path difference calculating unit 406, and an inclination angle calculating unit 407. To do.

The transmission antenna 401 and the reception antennas 402 and 403 are arranged in the front-rear direction of the vehicle body 3, and the transmission antenna 401 is disposed between the two reception antennas 402 and 403.
The transmission unit 404 outputs an oscillation signal having a predetermined frequency to the transmission antenna 401. The transmission antenna 401 radiates an oscillation signal as a radio wave to space. The radio wave radiated to the space is reflected on the road surface and propagates to the receiving antennas 402 and 403 as reflected waves. The receiving antennas 402 and 403 receive the reflected wave and output it as a received signal to the receiving unit 405.

  Based on the reception signals of the reception antennas 402 and 403, the propagation path difference calculation unit 406 returns to the reception antenna 403 and the propagation path length L 1 from when the radio wave is radiated until it is reflected on the road surface and returned to the reception antenna 402. The propagation path difference ΔL, which is the difference from the propagation path length L 2 until the arrival, is measured and output to the tilt angle calculation unit 407.

The tilt angle calculation unit 407 obtains the tilt angle θ by multiplying the propagation path difference ΔL by a predetermined coefficient, and outputs the tilt angle θ to the control signal generation unit 200.
A propagation time difference ΔT, a propagation path difference ΔL, which is a difference between a propagation time T1 from when a radio wave is radiated and reflected on the road surface to return to the receiving antenna 402 and a propagation time T2 to return to the receiving antenna 403, Further, the proportional relationship of the following equation (6) holds for the inclination angle θ. Here, c is the propagation speed of the radio wave, and c1 is a conversion coefficient for calculating the inclination angle θ from the propagation path difference ΔL.

ΔL = c × ΔT (6)
θ = c1 × ΔL

FIG. 5 is a diagram for explaining an inclination angle measured using the radio wave type inclination sensor 101a. In FIG. 5, the relative inclination angle φ of the vehicle body 3 with respect to the road surface with the gradient angle GRAD, and the inclination angle θ measured by the radio wave type inclination sensor 101a.
When the road surface is a flat surface, the inclination angle θ measured by the radio wave type inclination sensor 101a is equal to the relative inclination angle φ of the gradient angle GRAD with respect to the road surface.
On the other hand, when the road surface is uneven, the inclination angle θ measured by the radio wave type inclination sensor 101a is different from the relative inclination angle φ with respect to the road surface of the gradient angle GRAD, and becomes the inclination angle θ with respect to the radio wave irradiation road surface at that time. For this reason, the second control signal generation unit 203 performs statistical processing such as averaging processing on a large number of inclination angles θ measured at different points during traveling, and generates fluctuation components of the inclination angle θ due to road surface unevenness. The relative inclination angle φ at the gradient angle GRAD on the road surface that is suppressed and the unevenness is averaged (that is, equivalent to a flat road surface) is calculated.

  Even when the road surface is uneven, the inclination angle θ measured by the radio wave type inclination sensor 101a can accurately measure the inclination angle of the vehicle body 3 with respect to the local road surface where the radio wave is irradiated. Therefore, the first control signal generation unit 202 can accurately obtain the deviation amount Δφ of the inclination angle of the vehicle body 3 according to the passenger getting on and off or taking in and out of the luggage while the vehicle 2 is stopped.

  Further, since the radio wave type tilt sensor 101a can measure without being affected by wind, temperature change, noise, etc., the displacement amount Δφ can be measured with high accuracy while the vehicle 2 is stopped. .

  As described above, according to the first embodiment, the headlight optical axis control device 1 has the inclination angle measurement unit 100 that measures the inclination angle of the vehicle body 3 with respect to the road surface, and the inclination angle measured by the inclination angle measurement unit 100. A tilt angle measured by the tilt angle measuring unit 100 and a first control signal generating unit 202 that generates a first control signal for controlling the optical axis of the headlamp 5 to a predetermined angle from the relative angle change amount. A second control signal generation for calculating a relative inclination angle of the vehicle body 3 with respect to the road surface and generating a second control signal for controlling the optical axis of the headlamp 5 to a predetermined angle from the relative inclination angle. The optical axis of the headlamp 5 is controlled based on the first control signal when the unit 203 and the vehicle 2 are stopped, and based on the second control signal when the vehicle 2 is traveling. The optical axis control unit 300 is provided. For this reason, when the vehicle 2 is stopped, the optical axis control is performed based on the amount of change in the angle of the vehicle body 3 in response to passengers getting on / off or loading / unloading, and during the traveling of the vehicle 2 based on the inclination angle of the vehicle body 3 relative to the road surface. Optical axis control can be performed, and optimal optical axis control can always be performed regardless of the state of the vehicle 2 (running or stopped) and the road surface state (flat, uneven, slope, etc.) .

  Further, according to the first embodiment, the first control signal generation unit 202 holds the inclination angle measured by the inclination angle measurement unit 100 immediately after the vehicle 2 stops as the pre-change inclination angle, and the vehicle 2 stops. If there is a change in the inclination angle measured by the inclination angle measurement unit 100 during the calculation, the amount of deviation between the inclination angle before the change and the inclination angle after the change is calculated to obtain a relative angle change amount. It was configured to use. For this reason, the optimum optical axis control can be performed regardless of the state of the road surface while the vehicle is stopped, and irrespective of whether passengers get on and off or whether or not luggage is taken in and out.

  Further, according to the first embodiment, the second control signal generation unit 203 averages the inclination angles measured by the inclination angle measurement unit 100 so as to calculate the relative inclination angle of the vehicle body 3 with respect to the road surface. Configured. For this reason, the influence of the local unevenness | corrugation of a road surface can be suppressed, and optimal optical axis control can be performed irrespective of the state of a road surface.

  Further, according to the first embodiment, the tilt angle measuring unit 100 is configured by the radio wave type tilt sensor 101 a having one transmitting antenna 401 and two receiving antennas 402 and 403 installed in the front-rear direction of the vehicle body 3. The reception antennas 402 and 403 receive the radio waves radiated from the transmission antenna 401 toward the road surface, reflected by the road surface, and received, and the inclination angle of the vehicle body 3 is determined from the propagation time difference between the reception antennas 402 and 403. Measured. For this reason, the optical axis control device 1 for headlamps which can always perform optimal optical axis control irrespective of the state of the vehicle 2 and the road surface state can be realized by using the radio wave type tilt sensor 101a.

Embodiment 2. FIG.
In the second embodiment, an example in which the tilt sensor 101 of the headlamp optical axis control device 1 is configured by an ultrasonic tilt sensor 101b will be described. The headlamp optical axis control device according to the second embodiment and the vehicle on which the headlamp optical axis control device is installed are the headlamp optical axis control device 1 and the vehicle shown in FIGS. 1 and FIG. 2 are used in the following because they have the same configuration in FIG.

  FIG. 6 is a block diagram showing a configuration of an ultrasonic tilt sensor 101b. The ultrasonic tilt sensor 101b includes two ultrasonic sensors 501 and 502, two transmission / reception units 503 and 504, and a vehicle height difference calculation unit 505 that are arranged in the front-rear direction of the vehicle body 3 by a sensor interval W. And an inclination angle calculation unit 506.

The ultrasonic sensor 501 emits ultrasonic waves toward the road surface in accordance with instructions from the transmission / reception unit 503. The emitted ultrasonic wave is reflected by the road surface, received by the ultrasonic sensor 501, and output as a reception signal to the transmission / reception unit 503.
Similarly, the ultrasonic sensor 502 also emits ultrasonic waves toward the road surface in accordance with instructions from the transmission / reception unit 504. The emitted ultrasonic wave is reflected by the road surface, received by the ultrasonic sensor 502, and output to the transmission / reception unit 504 as a reception signal.

  Based on the received signals, the transmission / reception units 503 and 504 notify the vehicle height difference calculation unit 505 of the timing at which the ultrasonic waves are radiated toward the road surface and the timing at which the ultrasonic waves are reflected and returned again.

The vehicle height difference calculation unit 505 measures the propagation time T1 from the ultrasonic sensor 501 radiating the ultrasonic wave, reflected on the road surface, and returning to the ultrasonic sensor 501 again. From the propagation time T1 to the ultrasonic sensor 501 To calculate the vehicle height H1.
Similarly, the vehicle height difference calculation unit 505 measures the propagation time T2 until the ultrasonic wave is emitted from the ultrasonic sensor 502, reflected by the road surface, and returned to the ultrasonic sensor 502 again. The distance between the sonic sensor 502 and the road surface is calculated to determine the vehicle height H2.
The vehicle height difference calculation unit 505 outputs the calculated vehicle heights H1 and H2 to the inclination angle calculation unit 506.

  The tilt angle calculation unit 506 obtains the tilt angle θ from the following equation (7) using the sensor interval W of the ultrasonic sensors 501 and 502 in the vehicle front-rear direction and the vehicle heights H1 and H2, and generates the control signal generation unit 200. Output to.

θ = tan ⁻¹ {(H1−H2) / W} (7)

FIG. 7 is a diagram illustrating an inclination angle measured using the ultrasonic inclination sensor 101b. In FIG. 7, the relative inclination angle φ of the vehicle body 3 with respect to the road surface with the gradient angle GRAD, and the inclination angle θ measured by the ultrasonic type inclination sensor 101b.
When the road surface is a flat surface, the inclination angle θ measured by the ultrasonic inclination sensor 101b is equal to the relative inclination angle φ of the gradient angle GRAD with respect to the road surface.
On the other hand, when the road surface is uneven, the inclination angle θ measured by the ultrasonic inclination sensor 101b is different from the relative inclination angle φ with respect to the road surface of the gradient angle GRAD, and the inclination angle θ with respect to the ultrasonic irradiation road surface at that time Become. For this reason, the second control signal generation unit 203 performs statistical processing such as averaging processing on a large number of inclination angles θ measured at different points during traveling, and generates fluctuation components of the inclination angle θ due to road surface unevenness. The relative inclination angle φ at the gradient angle GRAD on the road surface that is suppressed and the unevenness is averaged (that is, equivalent to a flat road surface) is calculated.

  Even when the road surface is uneven, the inclination angle θ measured by the ultrasonic inclination sensor 101b can accurately measure the inclination angle of the vehicle body 3 with respect to the local road surface irradiated with ultrasonic waves. . Therefore, the first control signal generation unit 202 can accurately obtain the deviation amount Δφ of the inclination angle of the vehicle body 3 according to the passenger getting on and off or taking in and out of the luggage while the vehicle 2 is stopped.

  However, the ultrasonic tilt sensor 101b is affected by wind and noise. Therefore, unlike the case where the radio wave type tilt sensor 101a described in the first embodiment is used, the first control signal generation unit 202 sets the tilt angle θ measured while the vehicle 2 is stopped for a predetermined time. It is necessary to calculate the deviation amount Δφ using the average value obtained by the fractional averaging process.

  As described above, according to the second embodiment, the tilt angle measurement unit 100 is configured by the ultrasonic tilt sensor 101b having the two ultrasonic sensors 501 and 502 installed in the front-rear direction of the vehicle body 3, and the ultrasonic wave Each of the sensors 501 and 502 radiates an ultrasonic wave toward the road surface, receives the ultrasonic wave reflected by the road surface, and detects the vehicle height, detects the vehicle height, and installs the ultrasonic sensors 501 and 502. The inclination angle of the vehicle body 3 is measured from the interval. For this reason, the optical axis control device 1 for headlamps which can always perform optimal optical axis control irrespective of the state of the vehicle 2 and the road surface state can be realized using the ultrasonic tilt sensor 101b.

  In the second embodiment, a sensor that measures the vehicle height by reflecting ultrasonic waves on the road surface is used as a distance sensor that detects the vehicle height. However, the present invention is not limited to this, and light (laser) is used. A sensor that measures the vehicle height by reflecting the light on the road surface may be used.

Embodiment 3 FIG.
In the third embodiment, an example in which the inclination sensor 101 of the optical axis control device 1 for headlamps is configured by an acceleration type inclination sensor 101c will be described. The headlamp optical axis control device according to the third embodiment and the vehicle on which the headlamp optical axis control device is installed are the headlamp optical axis control device 1 and the vehicle shown in FIGS. 1 and FIG. 2 are used in the following because they have the same configuration in FIG.

  FIG. 8 is a block diagram illustrating a configuration of the acceleration type tilt sensor 101c. The acceleration type tilt sensor 101c includes a biaxial acceleration sensor 601 and a tilt angle calculation unit 602.

  For example, the biaxial acceleration sensor 601 is installed in the vehicle body 3 so that the first measurement direction is the front-rear direction of the vehicle body 3 and the second measurement direction is the vertical direction of the vehicle 2. If the acceleration Ax in the longitudinal direction of the vehicle body 3 and the acceleration Az in the vertical direction of the vehicle body 3 are assumed, the inclination angle θ output by the inclination angle calculation unit 602 is expressed by the following equation (8).

θ = tan ⁻¹ (Az / Ax) (8)

  FIG. 9 is a diagram illustrating an inclination angle measured using the acceleration type inclination sensor 101c. Note that the angles θ and φ of the biaxial acceleration sensor 601 shown in FIG. 8 represent the case where the two-axis acceleration sensor 601 is installed in the vehicle body 3 in the inclined state shown in FIG.

  Here, when the relative inclination angle φ of the vehicle body 3 with respect to the road surface of the gradient angle GRAD, the inclination angle θ measured by the acceleration type inclination sensor 101c, the acceleration in the traveling direction of the vehicle 2 (hereinafter referred to as vehicle acceleration) Gc, and the gravitational acceleration G0. The accelerations Ax and Az measured by the biaxial acceleration sensor 601 are expressed by the following equation (9).

Ax = G0 × cos {π / 2− (φ + GRAD)} + Gc × cos (φ) (9)
Az = G0 × sin {π / 2− (φ + GRAD)} + Gc × sin (φ)

  Since the vehicle acceleration Gc component does not exist while the vehicle 2 is stopped, the equation (9) can be expressed as the following equation (10), and the inclination angle θ output from the inclination angle calculation unit 602 is expressed by the following equation (11). Become.

Ax = G0 × cos {π / 2− (φ + GRAD)} (10)
Az = G0 × sin {π / 2− (φ + GRAD)}

θ = tan ⁻¹ [sin {π / 2− (φ + GRAD)} / cos {π / 2− (φ + GRAD)}] (11)

  When the vehicle 2 is stopped and passengers get in and out or luggage is taken in and out, and the relative inclination angle φ of the vehicle body 3 changes from φ1 to φ2, the displacement amount of the inclination angle θ measured by the acceleration type inclination sensor 101c is Δφ. = Φ2−φ1. That is, the inclination angle θ when the vehicle is stopped changes only the relative inclination angle φ component of the vehicle body 3 while the gradient angle GRAD component of the road surface is constant.

  On the other hand, when the vehicle 2 is traveling, if the gravity acceleration G0 component is removed as an offset value from the accelerations Ax and Az immediately before traveling (that is, when the vehicle 2 is stopped), only the vehicle acceleration Gc component remains and is expressed by the following equation (12). be able to. Therefore, the inclination angle θ output from the inclination angle calculation unit 602 is expressed by the following equation (13).

Ax = Gc × cos (φ) (12)
Az = Gc × sin (φ)

θ = tan ⁻¹ {sin (φ) / cos (φ)} (13)

As described above, the acceleration type inclination sensor 101c measures an angle obtained by adding the inclination angle GRAD of the road surface and the inclination of the vehicle body 3.
When there is no road surface gradient, the inclination angle θ output by the acceleration type inclination sensor 101c is equal to the relative inclination angle φ.
On the other hand, when the road surface has a gradient, the biaxial acceleration sensor 601 also measures the gradient angle GRAD, so that the inclination angle θ output from the acceleration type inclination sensor 101c is different from the relative inclination angle φ. .

  On the other hand, when the gravitational acceleration G0 is removed as an offset value from the acceleration measured by the biaxial acceleration sensor 601, the inclination angle θ calculated from the acceleration Gc of the vehicle 2 is a relative inclination angle φ.

  Even when there is a gradient on the road surface, the first control signal generation unit 202 is configured so that the gradient angle GRAD of the inclination angle θ output from the acceleration type inclination sensor 101c is constant while the vehicle 2 is stopped. The amount of deviation Δφ of the inclination angle of the vehicle body 3 according to the entry / exit of the vehicle or the loading / unloading of the luggage, that is, the amount of deviation of the relative inclination angle φ can be obtained with high accuracy.

  As described above, according to the third embodiment, the tilt angle measuring unit 100 includes the acceleration type tilt sensor 101c having the biaxial acceleration sensor 601 that detects the longitudinal and vertical accelerations of the vehicle body 3, and the vehicle 2 When the vehicle 2 is stopped, the inclination angle of the vehicle body 3 is measured using the gravitational acceleration detected by the two-axis acceleration sensor 601, and when the vehicle 2 is traveling, the gravitational acceleration is corrected as an offset value. The inclination angle of the vehicle body 3 is measured using only the acceleration in the traveling direction. Therefore, it is possible to realize the headlight optical axis control apparatus 1 that can always perform the optimal optical axis control regardless of the state of the vehicle 2 and the road surface by using the acceleration type inclination sensor 101c.

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

  DESCRIPTION OF SYMBOLS 1 Headlight optical-axis control apparatus, 2 Vehicle, 3 Car body, 4 chassis, 5 Headlamp, 100 Inclination angle measurement part, 101 Inclination sensor, 101a Radio wave type inclination sensor, 101b Ultrasonic type inclination sensor, 101c Acceleration type tilt sensor, 200 control signal generation unit, 201 switching unit, 202 first control signal generation unit, 203 second control signal generation unit, 204 vehicle state determination unit, 300 optical axis control unit, 301 mechanism drive unit , 302 Optical axis control mechanism, 401 transmitting antenna, 402, 403 receiving antenna, 404 transmitting unit, 405 receiving unit, 406 propagation path difference calculating unit, 407 tilt angle calculating unit, 501, 502 ultrasonic sensor, 503, 504 transmitting / receiving unit , 505 Vehicle height difference calculation unit, 506 Inclination angle calculation unit, 601 Biaxial acceleration sensor, 602 Inclination angle calculation unit.

Claims (7)

An optical axis control device for a headlamp that controls an optical axis of a headlamp installed in a vehicle at a predetermined angle with respect to a road surface,
An inclination angle measuring unit for measuring an inclination angle of the vehicle with respect to the road surface;
A first control signal generating unit that generates a first control signal for controlling the optical axis of the headlamp to the predetermined angle from a relative angle change amount of the tilt angle measured by the tilt angle measuring unit; ,
A relative inclination angle of the vehicle with respect to the road surface is calculated from the inclination angle measured by the inclination angle measurement unit, and the optical axis of the headlamp is controlled to the predetermined angle from the relative inclination angle. A second control signal generation unit for generating the control signal;
An optical axis for controlling the optical axis of the headlamp based on the first control signal when the vehicle is stopped and based on the second control signal when the vehicle is traveling An optical axis control device for a headlamp, comprising: a control unit.   The first control signal generation unit holds the inclination angle measured by the inclination angle measurement unit immediately after the vehicle is stopped as a pre-change inclination angle, and the inclination angle measurement unit while the vehicle is stopped When the inclination angle measured in step 1 is changed, a deviation amount between the inclination angle before the change and the inclination angle after the change is calculated to obtain the relative angle change amount. The optical axis control device for headlamps according to 1.   The second control signal generation unit calculates an inclination angle of the vehicle relative to the road surface by averaging the inclination angles measured by the inclination angle measurement unit. The optical axis control device for a headlamp according to claim 2.   The inclination angle measurement unit has one transmission antenna and two reception antennas installed in the front-rear direction of the vehicle, radiates radio waves from the one transmission antenna toward the road surface, and reflects on the road surface. 4. The vehicle according to claim 1, wherein the returned radio waves are received by the two receiving antennas, and an inclination angle of the vehicle is measured from a propagation time difference between the two receiving antennas. 5. The optical axis control device for a headlamp according to claim 1.   The inclination angle measurement unit has two distance sensors installed in the front-rear direction of the vehicle, and each of the two distance sensors emits an ultrasonic wave or light toward the road surface and is reflected by the road surface and returned. 2. The vehicle according to claim 1, wherein the vehicle height is detected by receiving the ultrasonic wave or light, and the inclination angle of the vehicle is measured from a difference between the vehicle height and an installation interval between the two distance sensors. The optical axis control apparatus for headlamps of any one of Claim 3.   The inclination angle measurement unit includes an acceleration sensor that detects acceleration in the front-rear direction and the vertical direction of the vehicle, and uses the gravitational acceleration detected by the acceleration sensor when the vehicle is stopped. An inclination angle is measured, and when the vehicle is traveling, the gravitational acceleration is corrected as an offset value, and the inclination angle of the vehicle is measured using only the acceleration in the traveling direction of the vehicle. The optical axis control device for a headlamp according to any one of claims 1 to 3.   The vehicle state determination part which determines the stop and driving | running | working of the said vehicle based on the detected value of the vehicle speed sensor installed in the said vehicle is provided, The any one of Claims 1-6 characterized by the above-mentioned. Optical axis control device for headlamps.

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