JP6045517B2 - Vehicle tilt angle measuring device and optical axis control signal generating device - Google Patents

Description

  The present invention relates to a vehicle tilt angle measuring device that detects a tilt angle of a vehicle and an optical axis control signal generating device that generates an optical axis control signal of a headlamp using the same.

  Conventionally, as a device for detecting the tilt angle of a vehicle, there is a device configured by a three-axis acceleration sensor having a measurement axis in each of the longitudinal direction, the lateral direction, and the vertical direction of the vehicle and a signal processing unit (for example, see Patent Document 1). ). This apparatus calculates a vehicle inclination angle and a road surface gradient angle from sensor outputs measured from acceleration in the vehicle traveling direction and gravitational acceleration while the vehicle is traveling.

JP 2008-185418 A

  In the conventional apparatus described in Patent Document 1, the vehicle inclination angle and the road surface inclination angle are calculated during acceleration and deceleration while the vehicle is running. However, during acceleration / deceleration, the vehicle nose-dive or squats, so the vehicle inclination angle during acceleration / deceleration deviates from the vehicle inclination angle when stopped. Moreover, the behavior is not always constant depending on the load weight and the road surface gradient angle. Therefore, there is a problem that the vehicle inclination angle and the road surface gradient angle when the vehicle is stopped cannot be calculated with high accuracy. Further, there has been a problem that the optimum control cannot be achieved if the optical axis control of the headlamp is performed based on the vehicle inclination angle that is not accurately calculated.

  The present invention has been made to solve the above-described problems, and obtains a vehicle tilt angle measuring device capable of accurately calculating the vehicle tilt angle while the vehicle is stopped, and uses this to optimize the optical axis. It is an object of the present invention to obtain an optical axis control signal generation device that can be controlled.

  The vehicle inclination angle measuring device according to the present invention includes an acceleration measuring unit that measures acceleration in the longitudinal direction of the vehicle, acceleration in the vertical direction of the vehicle, acceleration in a direction parallel to the road surface that is the vehicle traveling direction, and acceleration during vehicle travel. The road surface gradient angle of the vehicle position is calculated using the acceleration at acceleration and deceleration of the vehicle measured by the measurement unit and the gravitational acceleration, and the gravitational acceleration measured by the acceleration measurement unit while the vehicle is stopped A tilt angle measurement unit that calculates an inclination angle having information on a vehicle inclination angle and a road surface gradient angle, and a control signal generation unit that calculates a vehicle inclination angle from the inclination angle and the road surface gradient angle. is there.

  The vehicle inclination angle measuring device according to the present invention calculates a road surface gradient angle of a vehicle position using acceleration and gravity acceleration during acceleration and deceleration of the vehicle while the vehicle is traveling, and uses the acceleration of gravity while the vehicle is stopped. Since the inclination angle having the information of the angle and the road surface gradient angle is calculated and the vehicle inclination angle is calculated from the inclination angle and the road surface inclination angle, the vehicle inclination angle while the vehicle is stopped can be accurately calculated.

BRIEF DESCRIPTION OF THE DRAWINGS It is a block diagram which shows the vehicle inclination angle measuring device and optical axis control signal generator by Embodiment 1 of this invention. It is explanatory drawing of the acceleration measured while a vehicle stops. It is explanatory drawing of the acceleration measured during vehicle travel. It is explanatory drawing of the stable road surface which concerns on Embodiment 1 of this invention. It is explanatory drawing of the unstable road surface which concerns on Embodiment 1 of this invention. It is explanatory drawing of the other example of the unstable road surface which concerns on Embodiment 1 of this invention. It is a block diagram which shows the vehicle inclination angle measuring device and optical axis control signal generator by Embodiment 2 of this invention. It is explanatory drawing of the stable road surface which concerns on Embodiment 2 of this invention. It is explanatory drawing of the unstable road surface which concerns on Embodiment 2 of this invention. It is explanatory drawing of the other example of the unstable road surface which concerns on Embodiment 2 of this invention. It is a block diagram which shows the principal part of the vehicle tilt angle measuring apparatus and optical axis control signal generation apparatus by Embodiment 3 of this invention. It is a block diagram which shows the vehicle inclination angle measuring device and optical axis control signal generator by Embodiment 4 of this invention. It is explanatory drawing of the acceleration measured during the vehicle travel of the vehicle inclination angle measuring apparatus and optical axis control signal generation apparatus by Embodiment 4 of this invention.

Embodiment 1 FIG.
1 is a block diagram showing a vehicle tilt angle measuring apparatus and an optical axis control signal generating apparatus according to Embodiment 1 of the present invention.
The apparatus shown in FIG. 1 includes a first acceleration measurement unit 100, a second acceleration measurement unit 200, a vehicle stop determination unit 300, an inclination angle measurement unit 400, a road surface stability determination unit 500, and a control signal generation unit 600.

  The first acceleration measuring unit 100 is an acceleration measuring unit attached to the vehicle body of the vehicle, measures a combined acceleration that is a combined vector value of gravitational acceleration and acceleration in the direction parallel to the road surface during vehicle acceleration / deceleration. Output to the measurement unit 400. The second acceleration measurement unit 200 is an acceleration measurement unit attached to the chassis of the vehicle, measures acceleration in the road parallel direction during vehicle acceleration / deceleration, and outputs the acceleration to the tilt angle measurement unit 400 as vehicle acceleration.

  The vehicle stop determination unit 300 outputs a stop determination signal to the road surface stability determination unit 500 and the control signal generation unit 600 when it is determined that the vehicle is stopped, and when it is determined that the vehicle is traveling. The inclination angle measurement unit 400 measures the inclination angle θ3 including the vehicle inclination angle θ1 and the road surface gradient angle θ2 from the combined acceleration measured by the first acceleration measurement unit 100, and outputs the inclination angle θ3 to the control signal generation unit 600. Further, the inclination angle measurement unit 400 measures the road surface gradient angle θ2 from the combined acceleration measured by the first acceleration measurement unit 100 and the vehicle acceleration measured by the second acceleration measurement unit 200, and the control signal generation unit 600 Output to. The road surface stability determination unit 500 determines that the road surface gradient angle is constant when the variance of the road surface gradient angle in a section that has traveled a predetermined distance from the start of the vehicle is equal to or less than a predetermined value, and indicates the stability determination. The signal is output to the control signal generator 600.

The control signal generation unit 600 stores the inclination angle θ3 measured by the inclination angle measurement unit 400 while the vehicle stop signal is input from the vehicle stop determination unit 300. Further, when a travel determination signal is input from the vehicle stop determination unit 300, the inclination angle θ3 immediately before starting is held, and when a stability determination signal is input from the road surface stability determination unit 500, the road surface gradient is determined from the stored total angle θ3. Using the angle θ2, a vehicle tilt angle θ1 that is a vehicle tilt angle when the vehicle is stopped is calculated from the following equation. Further, the optical axis control angle θ4 is output based on the vehicle inclination angle θ1.
θ1 = θ3-θ2 (1)
θ4 = f (θ1−θ0) (2)
Here, θ0 is a vehicle inclination angle that is a preset optical axis angle reference. f is a function, and calculates the optical axis angle for controlling the optical axis so as to cancel the vehicle tilt angle displaced by Δθ10 = θ1−θ0. For example, the function f deviates the optical axis angle by −Δθ10 when the vehicle tilt angle is deviated by Δθ10.

Next, the detail of each part is demonstrated.
The first acceleration measuring unit 100 includes a biaxial acceleration sensor 101 having measurement axes in the front-rear direction, the left-right direction, and the up-down direction of the vehicle. As the two-axis acceleration sensor 101, an integrally configured semiconductor sensor is used. The second acceleration measuring unit 200 includes a speed sensor 201 that measures the speed of the vehicle from the number of rotations of the wheels. The inclination angle measurement unit 400 includes an inclination angle calculation unit 401 that calculates an inclination angle and a road surface gradient angle calculation unit 402 that calculates a road surface gradient angle. The road surface stability determination unit 500 includes a travel distance calculation unit 501, a dispersion calculation unit 502, a slip determination unit 503, a vehicle vibration calculation unit 504, and a road surface stability determination unit 505.

  The travel distance calculation unit 501 in the road surface stability determination unit 500 is a processing unit that calculates the travel distance L. The variance calculation unit 502 is a processing unit that calculates the variance value of the road surface gradient angle θ2 over a certain period of time. The slip determination unit 503 is a processing unit that determines the presence / absence of slip based on outputs from the first acceleration measurement unit 100 and the second acceleration measurement unit 200. The vehicle vibration calculation unit 504 is a processing unit that determines the presence or absence of road surface unevenness by calculating the Gz dispersion value of the biaxial acceleration sensor 101 for a predetermined time. The stability determination unit 505 is a processing unit that determines whether the road surface gradient angle is stable based on outputs from the travel distance calculation unit 501 to the vehicle vibration calculation unit 504.

  The control signal generation unit 600 includes a control angle calculation unit 601 and a control signal calculation unit 602. The control angle calculation unit 601 includes a stability determination signal output from the road surface stability determination unit 500, an inclination angle θ3 and road surface gradient angle θ2 output from the inclination angle measurement unit 400, and a vehicle stop output from the vehicle stop determination unit 300. It is a processing unit that calculates the vehicle inclination angle θ1 based on the signal. The control signal calculation unit 602 is a processing unit that generates a signal for optical axis control based on the vehicle inclination angle θ1 calculated by the control angle calculation unit 601.

2 and 3 are explanatory diagrams of measurement directions of acceleration measured by the biaxial acceleration sensor 101 and the speed sensor 201. FIG. The situation where the vehicle is not rolling will be described. The vehicle inclination angle is θ1, the road surface gradient angle is θ2, the inclination angle is θ3, the gravitational acceleration is g, and the acceleration in the vehicle traveling direction is acceleration in the road surface parallel direction.
The biaxial acceleration sensor 101 has measurement azimuths on the two axes of the longitudinal acceleration Gx of the vehicle and the vertical acceleration Gz of the vehicle. Here, the front-rear direction and the left-right direction of the vehicle are deviated in accordance with the deviation of the vehicle inclination angle due to the loading of luggage or the getting on and off of personnel.
The speed sensor 201 measures the vehicle speed v and calculates the acceleration a by time differentiation. The direction of the calculated acceleration a is the acceleration in the traveling direction of the vehicle and the direction parallel to the road surface. When the vehicle is inclined, there is an angle difference between the vehicle longitudinal direction and the vehicle traveling direction (direction parallel to the road surface). This angle difference is the vehicle inclination angle θ1.

While the vehicle is stopped, as shown in FIG. 2, the following equation is established for the vehicle inclination angle θ1, the road surface gradient angle θ2, the inclination angle θ3, and the output of the biaxial acceleration sensor 101.
Gx = −g × sin (θ1 + θ2) = − g × sin (θ3) (3)
Gz = g × cos (θ1 + θ2) = g × cos (θ3) (4)
While the vehicle is traveling, as shown in FIG. 3, the following equation is established for the vehicle inclination angle θ1, the road surface gradient angle θ2, the inclination angle θ3, the biaxial acceleration sensor output, and the vehicle acceleration a.
Gx = −g × sin (θ1 + θ2) + a × cos (θ1)
= −g × sin (θ3) + a × cos (θ1) (5)
Gz = g × cos (θ1 + θ2) + a × sin (θ1)
= G × cos (θ3) + a × sin (θ1) (6)

A mounting angle error caused by a difference in vehicle mounting is corrected by measuring in advance and multiplying by a rotation matrix.
The biaxial acceleration sensor 101 which is the first acceleration measuring unit 100 measures the longitudinal acceleration Gx of the vehicle and the vertical acceleration Gz of the vehicle and outputs them to the inclination angle measuring unit 400 and the road surface stability determining unit 500. The speed sensor 201 in the second acceleration measuring unit 200 measures the vehicle speed v and outputs the vehicle speed v and the acceleration a obtained by time differentiation to the inclination angle measuring unit 400 and the road surface stability determining unit 500.

  The vehicle stop determination unit 300 determines that the vehicle is stopped when the vehicle speed v is equal to or lower than a preset threshold value, and outputs a stop determination signal to the control signal generation unit 600. Otherwise, a travel determination signal is output. For example, when the vehicle speed v = zero, it is determined that the vehicle is stopped, and when the vehicle speed v> zero, it is determined that the vehicle is traveling.

The tilt angle calculation unit 401 in the tilt angle measurement unit 400 uses the output values Gx and Gz of the biaxial acceleration sensor 101 and the gravitational acceleration g, and the tilt angle of the vehicle tilt angle θ1 and the road surface gradient angle θ2 from the following equation (7) θ3 is calculated and output to the control angle calculation unit 601 in the control signal generation unit 600.
θ3 = (θ1 + θ2) = tan ⁻¹ (Gx / Gz) (7)
Equation (7) is derived from Equation (3) and Equation (4).

The road surface gradient angle calculation unit 402 in the inclination angle measurement unit 400 calculates the road surface gradient angle θ2 from the output values Gx and Gz of the biaxial acceleration sensor 101, the gravitational acceleration g, and the vehicle acceleration a by the following equation (8), and performs control. This is output to the control angle calculation unit 601 in the signal generation unit 600.
θ2 = sin− ¹ (( ⁻ Gx ² −Gz ² + a ² + g ² ) / (2 × a × g)) (8)
Equation (8) is derived from the simultaneous equations of Equation (5) and Equation (6).

  4-6 is explanatory drawing regarding the road surface stability which the road surface stability determination part 500 determines. The road surface stability determination unit 500 determines whether or not the road surface slope angle in a predetermined section from the vehicle stop position is constant. The situation where the road surface gradient angle is constant in the predetermined section from the stop position as shown in FIG. 4 is stable, and the situation where the road surface gradient angle changes from the stop position in the predetermined section as shown in FIG. 5 is unstable. Furthermore, as shown in FIG. 6, even when the road surface is not smooth and has an uneven surface, and the average road surface inclination angle θ2 is constant, the road surface is unstable.

  The travel distance calculation unit 501 in the road surface stability determination unit 500 calculates the travel distance L by using the vehicle speed v measured by the speed sensor 201 and always sets the vehicle travel start time to 0 m, and outputs it to the stability determination unit 505. Specifically, the travel distance L is on the order of several meters at most. The road surface gradient angle dispersion calculation unit 502 calculates a dispersion value of the road surface gradient angle θ2 calculated by the road surface gradient angle calculation unit 402 over a fixed time, and outputs the dispersion value VAR_θ2 to the stability determination unit 505. Specifically, there is 0.01 as a threshold value. The slip determination unit 503 compares the difference between the time differential value of the acceleration Gx measured by the biaxial acceleration sensor 101 and the time differential value of the acceleration a measured by the speed sensor 201, and determines that there is no slip if it is within a predetermined threshold. The signal is output to the stability determination unit 505. The vehicle vibration calculation unit 504 calculates a Gz variance value of the biaxial acceleration sensor 101 for a predetermined time, and outputs the Gz variance value to the stability determination unit 505. The stability determination unit 505 determines that the travel distance L is equal to or less than a predetermined threshold, the road surface gradient angle variance value VAR_θ2 is equal to or less than a predetermined threshold, a slip no determination signal is input, and the Gz variance value is equal to or less than a predetermined threshold. When it is determined that the road gradient angle is stable, a stability determination signal is output to the control signal generator 600.

The control angle calculation unit 601 of the control signal generation unit 600 stores θ3 output from the tilt angle calculation unit 401 when the vehicle stop signal is input, and the latest tilt angle θ3 when the input of the vehicle stop signal stops. Hold. On the other hand, the control angle calculation unit 601 stores the road surface gradient angle θ2 output from the road surface gradient angle calculation unit 402 when the vehicle travel signal is input. When the stability determination signal is input, the control angle calculation unit 601 The vehicle inclination angle θ1 is calculated from the road surface gradient angle θ2 by the following equation (9).
θ1 = θ3−θ2 (9)
Since it is determined that the road gradient angle has not changed from the vehicle stop position, the vehicle inclination angle θ1 while the vehicle is stopped can be directly measured by subtracting the road gradient angle θ2 from the inclination angle θ3.
The correction amount Δθ10 of the optical axis control angle from the vehicle tilt angle θ1 and the preset reference angle θ0 is:
Δθ10 = θ1-θ0 (10)
It is obtained.

The control signal calculation unit 602 generates and outputs an optical axis control angle θ4 based on the calculated correction amount Δθ10.
θ4 = f (Δθ10) (11)
Here, f is a function for determining the optical axis angle from the vehicle tilt angle.
As a result, an optical axis control device (not shown) controls the optical axis of the headlamp. Since this operation is known, the description thereof is omitted here.

  As described above, in the first embodiment, the inclination angle immediately before starting the vehicle is measured, and the road surface gradient angle is calculated immediately after starting the vehicle. Therefore, the vehicle inclination while the vehicle is stopped by subtracting the road surface inclination angle from the inclination angle. The angle can be calculated with high accuracy. In addition, the optical axis can be optimally controlled using the vehicle inclination angle calculated with high accuracy.

  As described above, according to the vehicle inclination angle measuring apparatus of the first embodiment, the acceleration for measuring the longitudinal acceleration of the vehicle, the vertical acceleration of the vehicle, and the acceleration parallel to the road surface that is the vehicle traveling direction. The road surface gradient angle of the vehicle position is calculated using the measurement unit and the acceleration and gravitational acceleration during acceleration and deceleration of the vehicle measured by the acceleration measurement unit while the vehicle is running, and the gravitational acceleration measured by the acceleration measurement unit while the vehicle is stopped Is used to calculate a vehicle inclination angle from the inclination angle and the road surface gradient angle, and an inclination angle measurement unit that calculates an inclination angle having information on the vehicle inclination angle and the road surface inclination angle, which is an inclination angle in the front-rear direction of the vehicle Since the signal generation unit is provided, the vehicle inclination angle while the vehicle is stopped can be calculated with high accuracy. Even if the vehicle inclination angle changes due to people getting on and off or loading luggage while the vehicle is stopped, the vehicle inclination angle when the vehicle is stopped can be accurately determined by subtracting the measured road surface gradient angle from the measured inclination angle. Can be calculated.

  In addition, according to the vehicle inclination angle measuring apparatus of the first embodiment, the control signal generation unit uses the inclination angle measured immediately before the start of the vehicle and the road surface gradient angle measured immediately after the start of the vehicle. Therefore, the vehicle inclination angle when the vehicle is stopped can be calculated with high accuracy.

  In addition, according to the vehicle inclination angle measuring apparatus of the first embodiment, the road surface stability determination unit that determines whether the road surface gradient from the vehicle stop position to immediately after the vehicle starts is stable, and the control signal generation unit includes the road surface Since the vehicle tilt angle is calculated when it is determined that the stability determination unit is stable, the vehicle tilt angle while the vehicle is stopped can be calculated with higher accuracy.

  Further, according to the vehicle inclination angle measuring device of the first embodiment, the road surface stability determination unit determines whether or not the fluctuation range of the road surface gradient angle measured when moving a predetermined distance from the stop position is within the set range. Therefore, it can be accurately determined whether or not the road gradient is stable.

  In addition, according to the vehicle inclination angle measuring apparatus of the first embodiment, the acceleration measuring unit calculates the acceleration in the direction parallel to the road surface by differentiating the vehicle speed of the vehicle, so that the acceleration of the vehicle is accurately obtained. be able to.

  In addition, according to the vehicle tilt angle measuring apparatus of the first embodiment, the acceleration measuring unit is an integrated semiconductor sensor as an acceleration sensor that measures the longitudinal acceleration of the vehicle and the vertical acceleration of the vehicle. Therefore, the acceleration measuring unit can be reduced in size and cost.

  Further, according to the optical axis control signal generation device of the first embodiment, the control signal generation unit generates an optical axis control signal for controlling the optical axis of the vehicle headlamp using the vehicle inclination angle. As a result, the optical axis can be optimally controlled.

Embodiment 2. FIG.
In the first embodiment, the method for calculating the vehicle tilt angle when the vehicle stops and accelerates is described. On the other hand, in the second embodiment, a method of calculating the vehicle inclination angle when the vehicle decelerates and stops will be described. It is another form of the optical-axis control signal generation apparatus which produces | generates the control signal for optical-axis control.

FIG. 7 is a configuration diagram illustrating the vehicle tilt angle measurement device and the optical axis control signal generation device according to the second embodiment.
The apparatus shown in FIG. 7 includes a first acceleration measuring unit 100, a second acceleration measuring unit 200, a vehicle stop determining unit 300, an inclination angle measuring unit 400, a road surface stability determining unit 700, and a control signal generating unit 800. Here, the first acceleration measurement unit 100 to the tilt angle measurement unit 400 are the same as the configuration of the first embodiment shown in FIG.

  The road surface stability determination unit 700 generates a stability determination signal that determines that the road surface gradient angle is constant when the variance value of the road surface gradient angle at a predetermined distance from vehicle deceleration to stop is equal to or less than a predetermined value. Output to 800.

When the travel signal is input and the stability determination signal is input, the control signal generation unit 800 holds and stores the road surface gradient angle θ2 calculated by the road surface gradient angle calculation unit 402. Further, while the vehicle stop signal is being input, the road surface gradient angle θ2 is kept, and when the inclination angle θ3 measured by the inclination angle measurement unit 400 is input, the vehicle is expressed by the following equation (12) from θ2 and θ3. Calculate the vehicle tilt angle when stopped.
θ1 = θ3-θ2 (12)
An optical axis control angle θ4 is output based on the vehicle tilt angle θ1.
θ4 = f (θ1−θ0) (13)
Here, θ0 is a vehicle inclination angle that is a preset optical axis angle reference. f is a function, and calculates the optical axis angle for controlling the optical axis so as to cancel the vehicle tilt angle displaced by Δθ10 = θ1−θ0.

  The control signal generation unit 800 continues to calculate the vehicle tilt angle θ1 while the vehicle stop signal is input from the vehicle stop determination unit 300, and stores and holds the vehicle tilt angle θ1 when the vehicle travel signal is input again. . This means that the optical axis control is always carried out so as to cancel out the deviation even if the vehicle tilt angle is deviated and the optical axis is deviated due to passengers getting on and off or loading of luggage while the vehicle is stopped. ing.

Next, the details of each part will be described focusing on the parts different from the first embodiment.
The road surface stability determination unit 700 includes a travel distance calculation unit 701, a dispersion calculation unit 702, a slip determination unit 703, a vehicle vibration calculation unit 704, and a stability determination unit 705. The travel distance calculation unit 701 is a processing unit that calculates the travel distance L immediately before the stop and outputs the time required for the travel distance L. The variance calculation unit 702 is a processing unit that calculates a variance value for a time required for the travel distance L of the road surface gradient angle θ2. The slip determination unit 703 is a processing unit that determines the presence or absence of slip based on outputs from the first acceleration measurement unit 100 and the second acceleration measurement unit 200. The vehicle vibration calculation unit 704 is a processing unit that determines the presence or absence of unevenness on the road surface by calculating the Gz dispersion value of the biaxial acceleration sensor 101 during the time required for the travel distance L. The stability determination unit 705 is a processing unit that determines whether the road surface gradient angle is stable based on outputs from the travel distance calculation unit 701 to the vehicle vibration calculation unit 704.

  The control signal generation unit 800 includes a control angle calculation unit 801 and a control signal calculation unit 802. The basic function of the control angle calculation unit 801 is the same as that of the control angle calculation unit 601 of the first embodiment, except that the vehicle inclination angle is calculated during the period from when the vehicle is running to when the vehicle is stopped. Yes. Similar to the control signal calculation unit 602 of the first embodiment, the control signal calculation unit 802 is a processing unit that generates a signal for optical axis control based on the vehicle tilt angle θ1 calculated by the control angle calculation unit 801. .

  8-10 is explanatory drawing regarding the road surface stability which the road surface stability determination part 700 determines. The road surface stability determination unit 700 determines whether or not the road surface gradient angle in a predetermined section from when the vehicle is decelerated to when it is stopped is constant. It is the order of the last section of several meters at most to stop. As shown in FIG. 8, it is determined that the road surface gradient angle from a few meters before the stop position to the stop position is constant is stable. As shown in FIG. 9, the situation in which the road surface gradient angle changes immediately before stopping is made unstable. Furthermore, as shown in FIG. 10, even when the road surface is not smooth and has an uneven surface, the average road surface inclination angle θ2 is also unstable.

  When a travel signal is input from the vehicle stop determination unit 300, the travel distance calculation unit 701 in the road surface stability determination unit 700 travels a past distance L set in advance using the vehicle speed v measured by the speed sensor 201. Times t1 to t2 required for the calculation are calculated and output to the variance calculation unit 702, the slip determination unit 703, and the vehicle vibration calculation unit 704. Specifically, the travel distance L is on the order of several meters at most.

  The variance calculation unit 702 calculates a variance value of the road surface gradient angle θ2 calculated by the road surface gradient angle calculation unit 402 at the input t1 to t2 for a certain period of time, and outputs the variance value VAR_θ2 to the stability determination unit 705. Specifically, there is 0.01 as a threshold value. The slip determination unit 703 compares the difference between the time differential value of the acceleration Gx measured by the biaxial acceleration sensor 101 and the time differential value of the acceleration a measured by the speed sensor 201, and determines that there is no slip if it is within a predetermined threshold. The signal is output to the stability determination unit 705. The vehicle vibration calculation unit 704 calculates the Gz variance value of the biaxial acceleration sensor 101 at the input t1 to t2, and outputs the Gz variance value to the stability determination unit 705. The stability determination unit 705 determines that the road surface slope angle is stable when the road surface slope angle dispersion value VAR_θ2 is equal to or smaller than a predetermined threshold value, a slip non-determination signal is input, and the Gz dispersion value is equal to or smaller than the predetermined threshold value. The stability determination signal is output to the control signal generation unit 800.

The control angle calculation unit 801 in the control signal generation unit 800 outputs a road surface gradient output from the road surface gradient angle calculation unit 402 when the stability determination signal is input immediately before the input changes from the vehicle travel signal to the vehicle stop signal. The angle θ2 is stored. During the input of the vehicle stop signal, the vehicle inclination angle θ1 is calculated from the stored road surface gradient angle θ2 and the inclination angle θ3 calculated by the inclination angle calculation unit 401 from the following equation (14).
θ1 = θ3−θ2 (14)
It is possible to directly measure the vehicle inclination angle θ1 when the vehicle is stopped by measuring the road gradient angle at the vehicle stop position in advance and subtracting the road gradient angle θ2 from the inclination angle θ3. Even if the vehicle inclination angle θ1 due to the passenger getting on and off and loading of the load changes while the vehicle is stopped, the road surface inclination angle is measured in advance, so the vehicle inclination angle is calculated directly from the equation (14).
The correction amount Δθ10 of the optical axis control angle from the vehicle tilt angle θ1 and the preset reference angle θ0 is:
Δθ10 = θ1-θ0 (15)
It is obtained.
The control signal calculation unit 802 generates and outputs an optical axis control angle θ4 based on the calculated correction amount Δθ10.
θ4 = f (Δθ10) (16)
Here, f is a function for determining the optical axis angle from the vehicle tilt angle.

  As described above, according to the second embodiment, the road surface gradient angle is measured immediately before the vehicle is stopped, and the vehicle inclination while the vehicle is stopped is obtained by subtracting the road surface gradient angle measured in advance from the inclination angle measured while the vehicle is stopped. The angle can be calculated with high accuracy. In addition, even if the vehicle inclination angle changes due to people getting on and off or loading luggage while the vehicle is stopped, the vehicle inclination angle while the vehicle is stopped can be accurately obtained by subtracting the measured road slope angle from the measured inclination angle. It can be calculated well. In addition, the optical axis can be optimally controlled from the vehicle inclination angle calculated with high accuracy.

  As described above, according to the vehicle inclination angle measuring device of the second embodiment, the control signal generation unit calculates the vehicle inclination angle using the road surface gradient angle measured immediately before the vehicle stops. It is possible to accurately calculate the vehicle inclination angle when the vehicle is stopped.

  Moreover, according to the vehicle inclination angle measuring apparatus of the second embodiment, the road surface stability determination unit that determines whether the road surface gradient from immediately before the vehicle stops to the stop position is stable is provided, and the control signal generation unit includes the road surface stability Since the vehicle inclination angle is calculated when it is determined that the degree determination unit is stable, the vehicle inclination angle while the vehicle is stopped can be calculated with higher accuracy.

  Further, according to the vehicle inclination angle measurement device of the second embodiment, the road surface stability determination unit determines whether the fluctuation range of the road surface gradient angle measured when moving a predetermined distance immediately before stopping is within the set range. Since the determination is based on no, it can be accurately determined whether or not the road gradient is stable.

Embodiment 3 FIG.
The third embodiment is an example in which one of the outputs of the control signal generation unit 600 of the first embodiment and the control signal generation unit 800 of the second embodiment is selected and a control signal is output.
FIG. 11 is a configuration diagram illustrating a main part of the optical axis control signal generation device according to the third embodiment. As illustrated, in the third embodiment, the control signals of the control signal generation unit (1) 600 of the first embodiment and the control signal generation unit (2) 800 of the second embodiment are input, and either control signal is input. Is provided with a control signal selection unit 900 that selects and outputs. Here, the control signal is either one or both of a signal indicating the vehicle tilt angle θ1 and a signal indicating the optical axis control angle θ4. The control signal selection unit 900 adopts and outputs the latest control signals of the input signals of both the control signal generation unit (1) 600 and the control signal generation unit (2) 800.

  As described above, in the third embodiment, the road surface gradient angle immediately before the vehicle stops and immediately after the start is measured, and the vehicle inclination angle while the vehicle is stopped is accurately calculated by subtracting the road surface gradient angle from the inclination angle while the vehicle is stopped. be able to. In addition, even if the vehicle inclination angle changes due to people getting on and off or loading luggage while the vehicle is stopped, the vehicle inclination angle while the vehicle is stopped can be accurately obtained by subtracting the measured road slope angle from the measured inclination angle. It can be calculated well. The optical axis can be optimally controlled from the vehicle inclination angle calculated with high accuracy.

  As described above, according to the vehicle inclination angle measuring apparatus of the third embodiment, the vehicle inclination angle calculated using the road surface inclination angle measured immediately before the vehicle stops, the inclination angle measured immediately before the vehicle starts, and the vehicle Since the vehicle has a control signal selection unit that selects any one of the vehicle inclination angles calculated using the road surface inclination angle measured immediately after starting the vehicle, the vehicle is stopped depending on the state of the vehicle. The tilt angle can be calculated with high accuracy.

Embodiment 4 FIG.
In the first to third embodiments, the second acceleration measuring unit 200 uses the speed sensor 201 based on wheel rotation to measure the vehicle speed. The speed sensor 201 has a problem that an error occurs in the acceleration calculated when the wheel is idling. In the first and second embodiments, the road surface stability determination unit 500 (700) causes the slip determination unit 503 (703) to determine that the road surface is unstable when the wheel slips and the control signal calculation unit 602 (802) determines the vehicle inclination angle. It solves the problem that measurement error occurs by not calculating. As a result, no measurement error occurs, but there is a problem in that the frequency of measuring the vehicle tilt angle by the control signal calculation unit 602 (802) decreases. The fourth embodiment is an example that solves this problem.

  FIG. 12 is a configuration diagram illustrating the vehicle tilt angle measurement device and the optical axis control signal generation device according to the fourth embodiment. Based on the configuration of the first embodiment, a non-contact speed sensor 1001 is used as the second acceleration measurement unit 200a instead of the speed sensor 201 for measuring the vehicle speed. Further, the road surface stability determination unit 500a deletes the slip determination unit 503 in the first embodiment, and the stability determination unit 505a is based on the outputs of the travel distance calculation unit 501, the dispersion calculation unit 502, and the vehicle vibration calculation unit 504. It is configured to determine whether or not the road surface gradient angle is stable. Since other configurations are the same as those of the first embodiment shown in FIG. 1, the same reference numerals are given to corresponding portions, and descriptions thereof are omitted.

  As the non-contact speed sensor 1001, for example, a millimeter wave radar is used. In this millimeter wave radar, when the frequency of the transmitted millimeter wave is reflected back to the road surface, the frequency is shifted in proportion to the speed due to the Doppler effect. The speed is calculated by measuring the shift amount. Since non-contact measurement is performed, the vehicle acceleration a can be accurately measured regardless of the idling of the wheels.

  FIG. 13 is an explanatory diagram of acceleration measured while the vehicle is traveling. Since the non-contact speed sensor 1001 is used as the second acceleration measuring unit 200a, the vehicle acceleration a can be measured with high accuracy, so there is no need to consider whether or not the wheels are idling. For this reason, the slip determination part 503 of Embodiment 1 can be excluded as the road surface stability determination part 500a. The stability determination unit 505a determines that the road surface gradient angle is stable when the travel distance L is equal to or smaller than a predetermined threshold, the road surface gradient angle variance value VAR_θ2 is equal to or smaller than the predetermined threshold value, and the Gz variance value is equal to or smaller than the predetermined threshold value. The stability determination signal is output to the control signal generation unit 600.

  In the above example, the case where the non-contact speed sensor 1001 is applied to the first embodiment has been described. However, the non-contact speed sensor 1001 may be applied to the configuration of the second embodiment.

  As described above, according to the vehicle tilt angle measurement device and the optical axis control signal generation device of the fourth embodiment, the acceleration measurement unit is non-contact as a sensor that measures the vehicle speed for obtaining the vehicle longitudinal acceleration. Since the speed sensor is used, the vehicle acceleration can be accurately measured even when the wheel slips and the frequency at which the vehicle tilt angle can be calculated can be improved.

  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 100 1st acceleration measurement part, 101 2 axis | shaft acceleration sensor, 200, 200a 2nd acceleration measurement part, 201 Speed sensor, 300 Vehicle stop determination part, 400 Inclination angle measurement part, 401 Inclination angle calculating part, 402 Road surface gradient angle Calculation unit, 500, 500a, 700 Road surface stability determination unit, 501, 701 Travel distance calculation unit, 502, 702 Dispersion calculation unit, 503, 703 Slip determination unit, 504, 704 Vehicle vibration calculation unit, 505, 505a, 705 Stable Degree determination unit, 600,800 control signal generation unit, 601,801 control angle calculation unit, 602,802 control signal calculation unit, 900 control signal selection unit, 1001 non-contact speed sensor.

Claims (12)

An acceleration measuring unit that measures acceleration in the longitudinal direction of the vehicle, acceleration in the vertical direction of the vehicle, and acceleration in a direction parallel to the road surface that is the vehicle traveling direction;
The road surface gradient angle of the vehicle position is calculated using acceleration and deceleration acceleration measured by the acceleration measurement unit while the vehicle is running and the gravitational acceleration measured by the acceleration measurement unit while the vehicle is stopped. An inclination angle measuring unit for calculating an inclination angle having information on a vehicle inclination angle that is an inclination angle in the front-rear direction of the vehicle and the road surface gradient angle;
A vehicle inclination angle measuring device comprising: a control signal generation unit that calculates the vehicle inclination angle from the inclination angle and the road surface gradient angle.   The vehicle inclination angle measuring device according to claim 1, wherein the control signal generation unit calculates the vehicle inclination angle using a road surface gradient angle measured immediately before the vehicle stops. A road surface stability determination unit that determines whether the road surface gradient from immediately before the vehicle stop to the stop position is stable,
3. The vehicle inclination angle measuring device according to claim 1, wherein the control signal generation unit calculates the vehicle inclination angle when it is determined that the road surface stability determination unit is stable. 4. .   The vehicle according to claim 3, wherein the road surface stability determination unit determines whether or not a fluctuation range of a road surface gradient angle measured when moving a predetermined distance immediately before stopping is within a set range. Inclination angle measuring device.   The said control signal production | generation part calculates the said vehicle inclination angle using the inclination angle measured just before the start of a vehicle, and the road surface gradient angle measured immediately after the start of the said vehicle. Vehicle tilt angle measuring device. A road surface stability determination unit that determines whether the road surface gradient from the vehicle stop position to immediately after the vehicle starts is stable,
6. The vehicle inclination angle measuring device according to claim 1, wherein the control signal generation unit calculates the vehicle inclination angle when it is determined that the road surface stability determination unit is stable. .   The vehicle slope according to claim 6, wherein the road surface stability determination unit determines whether or not a fluctuation range of a road surface gradient angle measured when moving a predetermined distance from the stop position is within a set range. Angle measuring device.   The vehicle inclination angle measurement according to any one of claims 1 to 7, wherein the acceleration measurement unit calculates an acceleration in a direction parallel to the road surface by differentiating a vehicle speed of the vehicle. apparatus.   The said acceleration measurement part uses the semiconductor-type sensor comprised integrally as an acceleration sensor which measures the acceleration of the front-back direction of a vehicle, and the acceleration of the up-down direction of a vehicle. The vehicle inclination angle measuring device according to any one of the above.   The said acceleration measurement part uses a non-contact speed sensor as a sensor which measures the vehicle speed for calculating | requiring the acceleration of the front-back direction of the said vehicle, The any one of Claims 1-9 characterized by the above-mentioned. Vehicle tilt angle measuring device. Using the vehicle inclination angle measuring device according to any one of claims 1 to 10,
The control signal generation unit generates an optical axis control signal for controlling an optical axis of a vehicle headlamp using the vehicle inclination angle.   Of the vehicle inclination angle calculated using the road gradient angle measured immediately before the vehicle stops, the inclination angle measured immediately before the start of the vehicle, and the vehicle inclination angle calculated using the road gradient angle measured immediately after the vehicle starts The vehicle tilt angle measuring device according to claim 1, further comprising a control signal selection unit that selects any one of the vehicle tilt angles.

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