WO2016013419A1

WO2016013419A1 - Vehicular headlight control device

Info

Publication number: WO2016013419A1
Application number: PCT/JP2015/069872
Authority: WO
Inventors: 和彦買場; 知之上谷; 龍水野
Original assignee: 株式会社デンソー
Priority date: 2014-07-25
Filing date: 2015-07-10
Publication date: 2016-01-28
Also published as: JP2016028924A

Abstract

The purpose of the present invention is to make it possible to precisely control the optical axis of a headlight regardless of whether a vehicle is accelerating or decelerating. The ECU (20) of this vehicular headlight control device detects the acceleration of a vehicle (5) and, on the basis of the detected acceleration, calculates the pitch angle of the vehicle (5) using a predetermined calculation method in which the acceleration is used. The calculation method differs depending at least on whether the vehicle (5) is accelerating or decelerating. The ECU (20) controls a headlight (10) that is mounted to the vehicle (5) so that the optical axis of said headlight (10) is oriented in a direction corresponding to the calculated pitch angle.

Description

Vehicle headlamp control device

The present invention relates to a vehicle headlamp control device that controls the optical axis direction of a headlamp mounted on a vehicle.

2. Description of the Related Art A so-called vehicle headlamp control device that adjusts the optical axis direction of a vehicle headlight according to a change in the posture (tilt) of the vehicle in the front-rear direction is known. In the vehicle headlamp control device, a pitch angle indicating a tilt angle of the vehicle in the front-rear direction with respect to the road surface is calculated, and the optical axis direction is adjusted based on the pitch angle.

As a method for obtaining the pitch angle, a method is known in which a vehicle height sensor is provided on the front wheel or rear wheel of the vehicle, and the vehicle is obtained based on the vehicle height value detected by the vehicle height sensor. On the other hand, in order to simplify the system configuration and suppress cost increase, a technique for obtaining the pitch angle of a vehicle without using a vehicle height sensor has been proposed (for example, see Patent Document 1).

In the technique described in Patent Document 1, an absolute inclination angle of a vehicle (an inclination angle with respect to a horizontal plane perpendicular to the direction of gravity) is calculated using an inclination sensor, and further, an acceleration of the vehicle is calculated. Then, the pitch angle of the vehicle is calculated using the absolute inclination angle, acceleration, and spring constant, and the optical axis direction is adjusted based on the calculated pitch angle.

JP 2001-341578 A

In the technique described in Patent Document 1, a constant value is used as a spring constant for calculation. Therefore, the relationship between acceleration and pitch angle is linear as a whole including acceleration and deceleration.
However, the relationship between the acceleration of the vehicle and the pitch angle is not actually linear, and at least the tendency of change differs between acceleration and deceleration. The reasons include various factors such as the fact that the spring constant of the suspension is actually different before and after, and the behavior of the vehicle is different between acceleration and deceleration. Therefore, in the technique described in Patent Document 1, since the pitch angle is calculated using a constant spring constant regardless of whether the vehicle is accelerating or decelerating, the calculation accuracy is low and the optical axis is controlled with high accuracy. Is difficult.

The present invention has been made in view of the above problems, and an object of the present invention is to enable accurate control of the optical axis of a headlamp regardless of whether the vehicle is accelerating or decelerating.

The vehicle headlamp control device of the present invention made to solve the above-described problems includes an acceleration detection unit, a pitch angle calculation unit, and a control unit.
The acceleration detection unit detects the acceleration of the vehicle. The pitch angle calculation unit calculates the pitch angle of the vehicle based on the acceleration detected by the acceleration detection unit using a predetermined calculation method using the acceleration. The calculation method differs at least depending on whether the vehicle is accelerating or decelerating. The control unit controls the optical axis based on the pitch angle calculated by the pitch angle calculation unit so that the optical axis of the headlamp mounted on the vehicle is directed in a direction corresponding to the pitch angle.

According to the vehicle headlamp control apparatus configured as described above, the pitch angle is calculated by using the detected acceleration and by a different calculation method depending on whether the vehicle is accelerating or decelerating. Therefore, the pitch angle can be calculated with high accuracy regardless of whether the vehicle is accelerating or decelerating, thereby controlling the optical axis of the headlamp with high accuracy regardless of whether the vehicle is accelerating or decelerating. be able to.

The pitch angle calculation unit may calculate the amount of variation in the pitch angle caused by the acceleration using the above calculation method based on the acceleration detected by the acceleration detection unit. Then, the pitch angle may be calculated using the calculated fluctuation amount. More specifically, a stopping pitch angle that is a stopping pitch angle may be calculated, and the pitch angle may be calculated by adding a fluctuation amount to the stopping pitch angle.

In addition, the code | symbol in the parenthesis described in the claim shows the correspondence with the specific means as described in embodiment mentioned later as one aspect, Comprising: The technical scope of this invention is limited is not.

(A) is explanatory drawing which shows schematic structure of the vehicle by which the headlamp optical-axis direction control apparatus of embodiment is mounted, (B) is a block diagram which shows schematic structure of the headlamp optical-axis direction control apparatus. It is explanatory drawing which shows schematic structure of a headlight. (A) to (D) are explanatory diagrams for explaining the relationship among the stopping pitch angle θp0, the pitch angle variation θpc, and the road gradient θg of the vehicle, respectively. (A) is a graph showing the relationship between acceleration and pitch angle variation during acceleration, and (B) is a graph showing the relationship between acceleration and pitch angle variation during deceleration. It is a flowchart which shows an optical axis control process. It is explanatory drawing which shows the variation | change_quantity calculation map.

Embodiments to which the present invention is applied will be described below with reference to the drawings.
(1) Configuration of Vehicle Headlight Control Device A vehicle headlight control device (hereinafter abbreviated as “headlight control device”) 1 of the present embodiment will be described with reference to FIGS. 1 (A) and 1 (B). explain. As shown in FIG. 1A, the headlamp control device 1 is mounted on a vehicle 5 and controls the optical axis of a headlight (headlamp) 10 of the vehicle 5. The headlamp control device 1 directly controls the optical axis control motor 15 provided in the headlight 10, thereby controlling the optical axis of the headlight 10. The headlamp control device 1 includes an ECU (vehicle acceleration detection unit, vehicle pitch angle calculation unit, optical axis control unit, stopping pitch angle calculation unit, stable state determination unit) 20, an inclination sensor 31, and a vehicle speed sensor. (Vehicle acceleration detection unit) 32.

The inclination sensor 31 is provided at a predetermined portion of the vehicle 5, detects the absolute inclination angle θa of the vehicle 5 (inclination angle with respect to a horizontal plane perpendicular to the direction of gravity), and outputs an inclination angle signal indicating the detection result to the ECU 20. . The vehicle speed sensor 32 detects the actual traveling speed of the vehicle 5 and outputs a vehicle speed signal indicating the detection result to the ECU 20.

The ECU 20 receives various signals including at least the inclination angle signal from the inclination sensor 31 and the vehicle speed signal from the vehicle speed sensor 32, and calculates the actual pitch angle θp of the vehicle 5 according to the various input signals. The actual pitch angle θp is the pitch angle of the vehicle 5 with respect to the road surface.

The ECU 20 controls the headlight 10 based on the calculated actual pitch angle θp so that the optical axis of the headlight 10 is directed in a direction corresponding to the actual pitch angle θp. Specifically, the optical axis is controlled by driving the motor 15 by outputting a drive signal corresponding to the calculated actual pitch angle θp to the motor 15.

As shown in FIG. 1B, the ECU 20 includes a CPU 21, a ROM 22, a RAM 23, a storage memory 24, and an input / output circuit 25.
The CPU 21 executes various arithmetic processes according to programs stored in the ROM 22 and other various memories.

The ROM 22 is a storage device that stores various programs and data executed by the CPU 21. A program of an optical axis control process (see FIG. 5) described later for controlling the optical axis of the headlight 10 is also stored in the ROM 22. The optical axis control processing program is not necessarily stored in the ROM 22, and may be stored in a storage device other than the ROM 22. The RAM 23 is a main storage device that is directly accessed by the CPU 21.

The storage memory 24 is a non-volatile storage device that can electrically rewrite the stored contents. In the storage memory 24, various programs and data are stored, and calculation results and the like may be appropriately stored in the process of the CPU 21 performing various calculations.

In the execution process of the optical axis control process (FIG. 5), which will be described later, the spring constants ka and kb used and various calculation results calculated may be stored in the RAM 23 or stored in the storage memory 24. May be.

The input / output circuit 25 is an interface for inputting / outputting various signals. Various signals input to the ECU 20 are input via the input / output circuit 25. A drive signal output from the ECU 20 to the motor 15 is also output via the input / output circuit 25.

(2) Configuration of Headlight The headlight 10 is a lighting device (front) for improving visibility in front of the vehicle and improving visibility of the vehicle 5 from outside by mainly irradiating light in front of the vehicle 5. Lighting). As shown in FIG. 2, the headlight 10 includes a lamp 11, a reflector 12, a support part 13, a movable part 14, and a motor 15.

The lamp 11 is a light emission source for irradiating the front of the vehicle, and examples thereof include a halogen bulb, an HID (High Intensity Discharge lamp), and the like. The reflector 12 is a reflecting material for reflecting the light beam from the lamp 11 toward the front of the vehicle.

The support portion 13 is provided on the lower side of the reflector 12 and supports the reflector 12 so as to be swingable in the vertical direction (in the direction of the circular arc in the figure). The movable portion 14 is provided on the upper side of the reflector 12, one end side is connected to the reflector 12 to support the reflector 12, and the other end side is connected to the motor 15. ).

The motor 15 drives the movable part 14 in the front-rear direction in accordance with a drive signal from the ECU 20. Although not shown, the motor 15 and the movable portion 14 are connected via a conversion mechanism that converts rotation of the motor 15 into linear motion of the movable portion 14.

When the motor 15 rotates based on the drive signal from the ECU 20, the movable portion 14 moves in the front-rear direction, whereby the reflector 12 swings up and down around the support point by the support portion 13. The lamp 11 is fixed relative to the reflector 12. For this reason, when the reflector 12 swings in the vertical direction, the optical axis of the lamp 11 also moves in the vertical direction. Therefore, the ECU 20 can appropriately control the optical axis of the lamp 11 by appropriately controlling the motor 15.

(3) Pitch angle variation associated with vehicle acceleration / deceleration Next, the pitch angle of the vehicle 5 will be described more specifically. In the present embodiment, the stopping pitch angle θp0, the actual pitch angle θp, the absolute inclination angle θa, the pitch angle variation θpc, and the road gradient θg are used as the angles related to the inclination of the vehicle 5.

The stopped pitch angle θp0 is a pitch angle when the vehicle 5 is stopped. The actual pitch angle θp is the current pitch angle of the vehicle 5. As described above, the absolute inclination angle θa is an inclination angle with respect to the horizontal plane, not with respect to the road surface. The pitch angle fluctuation amount θpc is a pitch angle fluctuation amount caused by the acceleration of the vehicle 5 when the vehicle 5 is traveling. The road gradient θg is an inclination angle of the road surface with respect to a horizontal plane.

FIG. 3A shows an example in which the vehicle 5 is stopped on a road whose road surface is parallel to the horizontal plane (that is, road gradient θg = 0 °), and the pitch angle θp0 during stopping of the vehicle 5 is 0 °. Yes.
In the example of FIG. 3B, the vehicle 5 is stopped on the road with the road gradient θg = 0 °, and the stopping pitch angle θp0 of the vehicle 5 is not 0 ° (for example, 2 °). . Depending on various factors such as the position of the center of gravity of the vehicle 5, the characteristics of the suspensions of the front and rear wheels, and the riding state of the occupants of the vehicle 5, the stop pitch angle θp0 may not be 0 °. FIG. 3B shows that the vehicle 5 has already slightly tilted forward while the vehicle is stopped. In some cases, contrary to FIG. 3B, the vehicle 5 may be in a state of being tilted backward while the vehicle 5 is stopped (stopped pitch angle θp0 is a positive value).

FIG. 3C illustrates a state in which the vehicle 5 having a stopped pitch angle θp0 = 0 ° is traveling on a road having a road gradient θg = 0 ° and is accelerating. When the vehicle 5 accelerates, the vehicle 5 tilts backward due to the inertial force, and the pitch angle of the vehicle 5 fluctuates (in this case, increases). In the example of FIG. 3 (C), the pitch angle variation amount θpc becomes a positive value instead of 0 due to acceleration, and thus the actual pitch angle θp is larger than θp0. As illustrated in FIG. 4A, the pitch angle variation θpc, which is the pitch angle variation during acceleration, increases as the acceleration increases.

FIG. 3D illustrates a state in which the vehicle 5 having a stopped pitch angle θp0 = 0 ° is traveling on a road having a road gradient θg> 0 ° and is decelerating. When the vehicle 5 decelerates, the vehicle 5 tilts forward due to inertial force, and the pitch angle of the vehicle 5 fluctuates (decreases in this case). In the example of FIG. 3D, the pitch angle fluctuation amount θpc becomes a negative value instead of 0 due to deceleration, and thus the actual pitch angle θp is smaller than θp0. As illustrated in FIG. 4B, the pitch angle fluctuation amount θpc at the time of deceleration decreases (increases in the negative direction) as the acceleration decreases (that is, as the deceleration increases).

Although a change in the pitch angle may occur due to a change in the road gradient, in the present embodiment, a change in the pitch angle due to the change in the road gradient is ignored.
As described above, when the vehicle 5 accelerates, the vehicle 5 tilts backward and the pitch angle increases. Specifically, as the acceleration increases, the increase amount of the pitch angle increases (that is, the pitch angle fluctuation amount θpc increases). Conversely, when the vehicle 5 decelerates, the vehicle 5 tilts forward and the pitch angle decreases. Specifically, as the acceleration decreases (the deceleration increases), the pitch angle decrease amount increases (that is, the pitch angle variation θpc increases in the negative direction).

In this embodiment, as will be described later, the pitch angle variation θpc is calculated by detecting the acceleration of the vehicle 5 and integrating the acceleration and the spring constant k for calculation. The calculation spring constant k (specifically, an acceleration spring constant ka and a deceleration spring constant kb, which will be described later) is a constant that directly indicates the spring constant of a specific spring (for example, a spring of a specific suspension of the vehicle 5). is not. The calculation spring constant k is a pseudo value reflecting an actual pitch angle variation characteristic during acceleration / deceleration of the vehicle 5 for calculating the pitch angle variation amount θpc using the calculation spring constant k and the acceleration α. Spring constant.

If the relationship between the acceleration and the pitch angle variation θpc is linear, the calculation spring constant k may be a constant value regardless of the acceleration.
However, the relationship between the acceleration and the pitch angle fluctuation amount θpc is not actually linear as illustrated in FIGS. 4A and 4B. Moreover, the tendency of the change in the pitch angle variation θpc with respect to acceleration differs between acceleration and deceleration. In other words, the characteristic of FIG. 4A that is point-symmetrically moved about the origin does not necessarily match the characteristic of FIG. 4B.

The characteristics shown in FIGS. 4 (A) and 4 (B) are merely examples, and the relationship between the acceleration and the pitch angle variation θpc depends on the spring constant of the front and rear suspensions of the vehicle 5 and the acceleration / deceleration of the vehicle 5. It depends on various factors such as the center of gravity movement characteristics. 4A and 4B, the rear wheel suspension spring (for example, the spring constant is 30 [N / mm]) is greater than the front wheel suspension spring (for example, the spring constant is 20 [N / mm]). The example of the characteristic of a hard vehicle is also shown.

As described above, the tendency of the change in the pitch angle fluctuation amount θpc with respect to acceleration differs between acceleration and deceleration. Therefore, in this embodiment, by using the spring constant k for calculation that is different between acceleration and deceleration, at least the difference in the characteristic change tendency during acceleration and deceleration is reflected in the calculation result. I have to.

(4) Description of Optical Axis Control Process Next, the optical axis control process executed by the ECU 20 will be described with reference to FIG. The CPU 21 of the ECU 20 repeatedly executes the optical axis control process of FIG. 5 at a predetermined control period while the power switch (for example, an ignition switch) of the vehicle 5 is turned on.

CPU21 will start the optical axis control process of FIG. 5, and will determine whether the vehicle 5 is drive | working by S110. This determination can be made based on, for example, a vehicle speed signal from the vehicle speed sensor 32.

If the vehicle 5 is stopped, the stopping pitch angle θp0 is calculated from the previous values of the absolute inclination angle θa and the road gradient θg in S120. Specifically, the stopping pitch angle θp0 is calculated by calculating θp0 = θa−θg. The absolute inclination angle θa is calculated every time the process of S160 described later is executed and stored in a storage device (for example, the RAM 23 or the storage memory 24). The road gradient θg is also calculated and stored in the storage device every time the process of S270 described later is executed. The process of S120 is a process of calculating the stopping pitch angle θp0 using the latest absolute inclination angle θa and road gradient θg stored in the storage device. Note that the previous value of at least one of the absolute inclination angle θa and the road gradient θg is not stored in the storage device, for example, when the power is first turned on to the ECU 20 or when the storage contents of the storage device disappear for some reason. In this case, an initial value stored in advance in the ROM 22 is used as the stopping pitch angle θp0. In the ROM 22, an initial value (for example, 0 °) of the stopped pitch angle θp0 is written at a specific timing such as when the vehicle 5 is shipped from the factory.

In S130, based on the tilt angle signal input from the tilt sensor 31, the current absolute tilt angle θa is calculated and stored in the storage device. In S140, it is determined whether or not the current absolute inclination angle θa calculated in S130 has changed from the previous value. The previous value here is the latest value stored in the storage device before the processing of S130, that is, the value used in the processing of S120.

In S140, if the absolute inclination angle θa calculated in S130 is the same as the previous value, the process returns to S110, but if it has changed from the previous value, the process proceeds to S150. In S150, the value of the stopped pitch angle θp0 is updated. Specifically, the stopping pitch angle θp0 calculated in S120 is corrected according to the amount of change from the previous value of the absolute inclination angle θa. For example, when the change amount of the absolute inclination angle θa from the previous value is Δθa, the stopping pitch angle θp0 is corrected by adding Δθa to the stopping pitch angle θp0 calculated in S120. Then, the value of the stopping pitch angle θp0 stored in the storage device is updated (overwritten) to the corrected value. After the process of S150, the process returns to S110.

As described above, when the vehicle 5 is stopped, the change in the absolute inclination angle θa is monitored, and if there is a change in the absolute inclination angle θa, the change is made by following the change and the stopping pitch angle θp0 is updated. The pitch angle θp0 is always kept up to date.

In S110, if the vehicle 5 is traveling, the process proceeds to S160. In S160, based on the tilt angle signal input from the tilt sensor 31, the current absolute tilt angle θa is calculated and stored in the storage device. In S170, the acceleration α of the vehicle 5 is calculated based on the vehicle speed signal input from the vehicle speed sensor 32. The acceleration α can be calculated, for example, by calculating a rate of change of the vehicle speed signal (for example, a discrete differential value in the present embodiment) based on at least one vehicle speed signal acquired in the past and the vehicle speed signal acquired this time. After the acceleration α is calculated, the process proceeds to a series of pitch angle calculation processes (S180 to S250) for calculating the pitch angle fluctuation amount θpc.

In S180, it is determined whether or not the acceleration of the vehicle 5 is constant. There are various methods for determining whether or not the acceleration is constant. For example, the acceleration α calculated in S170 this time is compared with the acceleration α calculated in S170 last time. However, if they are different, it can be determined that the acceleration is not constant. Further, for example, based on a plurality of accelerations α calculated from a specific timing in the past to the present, when it is considered that the fluctuation range of each acceleration is stable at a certain level or less, it may be determined that the acceleration is constant. Good. Of course, it may be determined whether the acceleration is constant (that is, the acceleration stable state where the acceleration is stable) by other methods.

If it is determined in S180 that the acceleration of the vehicle 5 is not constant, the pitch angle variation θpc is calculated as 0 in S250. That is, if the vehicle 5 is actually accelerating or decelerating and the pitch angle fluctuates due to the acceleration, but the acceleration is not constant, the reliability of the acceleration α calculated in S170 is reliable. There is a low possibility. In the present embodiment, rather than calculating the pitch angle variation θpc using such an unreliable acceleration α, the pitch angle variation θpc is set to 0 (that is, the variation due to acceleration is not considered). The pitch angle variation θpc is set to 0 when the acceleration is not constant based on the idea that the processing is more likely to result in the calculation of the actual pitch angle θp with higher accuracy. After the processing of S250, the process proceeds to S260.

If it is determined in S180 that the acceleration of the vehicle 5 is constant, it is determined in S190 whether the vehicle 5 is accelerating. If the acceleration α is a positive value, it is determined that acceleration is being performed, and the process proceeds to S200. In S200, the calculation spring constant k is set to a predetermined acceleration spring constant ka (stored in advance in the storage device). The acceleration spring constant ka and the deceleration spring constant kb, which will be described later, are both positive values, but the values differ between the two.

In S210, the pitch angle variation θpc is calculated by integrating the acceleration α calculated in S170 and the calculation spring constant k (here, k = ka) set in S200. After the process of S210, the process proceeds to S260.

If the acceleration α is 0 or less in S190, the process proceeds to S220. In S220, it is determined whether the vehicle 5 is decelerating. If the acceleration α is 0, it is determined that the vehicle is not decelerating (that is, traveling at a constant speed), and the process proceeds to S250. That is, the pitch angle fluctuation amount θpc is calculated as 0 when traveling at a constant speed.

In S220, when the acceleration α is a negative value, it is determined that the vehicle is decelerating, and the process proceeds to S230. In S230, the calculation spring constant k is set to a predetermined spring constant kb during deceleration. In S240, the acceleration α calculated in S170 and the calculation spring constant k (here, k = kb) set in S230 are integrated, and a value obtained by multiplying the integration result by −1 is used as a pitch angle variation amount θpc. calculate. Since the vehicle 5 tilts forward during deceleration, the pitch angle varies in the negative direction. Therefore, -1 is multiplied. After the process of S240, the process proceeds to S260.

The acceleration spring constant ka and the deceleration spring constant kb can be determined by various methods. For example, the characteristic of the pitch angle variation θpc with respect to acceleration as illustrated in FIG. 4 is actually measured for the vehicle 5, and the respective spring constants ka and kb are determined based on the measurement result. Also good. Further, for example, based on the characteristics of the front and rear suspensions of the vehicle 5 (for example, the characteristics of the suspension provided on each of the four wheels (damping characteristics of the shock absorber, the spring constant of the coil spring, etc.)) The calculation spring constants ka and kb may be determined in consideration of the center-of-gravity movement characteristics of the vehicle 5 during braking.

After calculating the pitch angle variation θpc by the series of pitch angle variation calculation processing of S180 to S250, the process proceeds to S260. In S260, the actual pitch angle θp is calculated. Specifically, the actual pitch angle θp is calculated by adding the pitch angle fluctuation amount θpc calculated in S210, S240 or S250 to the latest stopping pitch angle θp0 currently stored.

In S270, the road gradient θg is calculated by subtracting the actual pitch angle θp calculated in S260 from the latest absolute inclination angle θa calculated and stored in S160.
In S280, the optical axis of the headlight 10 is controlled based on the actual pitch angle θp calculated in S260. Specifically, based on the fact that the vehicle 5 is pitched by the actual pitch angle θp, as a result, the motor is set so that the optical axis is in a desired direction (for example, a direction downward by a predetermined angle from a direction parallel to the road surface). The optical axis is controlled by driving 15.

(5) Effects of Embodiment, etc. According to the headlamp control device 1 of the present embodiment described above, the acceleration α is calculated, and the actual pitch angle θp is calculated by a different calculation method depending on whether the vehicle 5 is accelerating or decelerating. Is calculated. Therefore, it is possible to accurately calculate the actual pitch angle θp regardless of whether the vehicle 5 is accelerating or decelerating, and thereby the optical axis of the headlight 10 can be determined regardless of whether the vehicle 5 is accelerating or decelerating. It can be controlled with high accuracy.

In the process of calculating the actual pitch angle θp, first, the pitch angle fluctuation amount θpc caused by the acceleration / deceleration of the vehicle 5 is calculated. At this time, the acceleration spring constant ka is used if the vehicle 5 is accelerating, and the deceleration spring constant kb is used if the vehicle 5 is decelerating. That is, the pitch angle fluctuation amount θpc is calculated using a calculation spring constant that varies depending on whether the vehicle 5 is accelerating or decelerating. Then, the actual pitch angle θp is calculated using the pitch angle fluctuation amount θpc. Therefore, by setting the acceleration spring constant ka and the deceleration spring constant kb to appropriate values that match the actual characteristics of the vehicle 5, it is possible to determine whether the vehicle 5 is accelerating or decelerating with a simple calculation method. Regardless, the optical axis of the headlight 10 can be accurately controlled.

Further, in the present embodiment, when the vehicle 5 is stopped, a stopped pitch angle θp0 that is a pitch angle in the stopped state is calculated. Then, the actual pitch angle θp is calculated by a simple calculation method of adding the pitch angle fluctuation amount θpc to the stopping pitch angle θp0. Therefore, the higher the accuracy of the stopped pitch angle θp0 and the higher the accuracy of the pitch angle variation θpc (that is, the more appropriate the values of the spring constants ka and kb), the more accurate the calculation of the actual pitch angle θp. Can be increased.

Further, in the present embodiment, when the acceleration of the vehicle 5 is constant, the pitch angle fluctuation amount θpc is calculated using the acceleration α and the calculation spring constant k. That is, when the acceleration of the vehicle 5 is in an unstable state, the pitch angle variation amount θpc is not calculated using the acceleration α calculated in the unstable state. Therefore, the calculation accuracy of the actual pitch angle θp during acceleration / deceleration of the vehicle 5 can be further increased as a whole.

[Other Embodiments]
As mentioned above, although embodiment of this invention was described, this invention can take a various form, without being limited to the said embodiment.

(1) It is not essential to determine one spring constant for calculation, one for acceleration and one for deceleration. For example, a plurality of types of acceleration spring constants ka different according to the acceleration α may be prepared as the acceleration spring constant ka used during acceleration. Specifically, for example, when the acceleration α is between 0 and a predetermined value, the first acceleration spring constant ka1 is used, and when the acceleration α is higher than the predetermined value, the second acceleration spring constant ka2 is used. A method may be adopted. Of course, three or more types of acceleration spring constants may be prepared and used depending on the acceleration. The same applies to the deceleration spring constant kb used during deceleration.

(2) In the above embodiment, when the acceleration of the vehicle 5 is constant, the pitch angle fluctuation amount θpc is calculated using the calculation spring constant k. However, regardless of whether the acceleration is constant or not. The pitch angle fluctuation amount θpc may be calculated using the calculation spring constant k.

(3) In the above embodiment, the calculation accuracy of the actual pitch angle θp can be improved by properly using the calculation spring constant k for acceleration and deceleration. However, the calculation method differs between acceleration and deceleration. There are other methods for calculating the actual pitch angle θp by using.

For example, a map (variation amount calculation map) in which acceleration and pitch angle variation amount θpc are associated may be prepared in advance. In the pitch angle variation calculation process in the optical axis control process shown in FIG. 5, the processing of S180 to S250 may be replaced with a process of calculating the pitch angle variation θpc using the variation calculation map. Good.

FIG. 6 shows an example of the fluctuation amount calculation map. The fluctuation amount calculation map 40 shown in FIG. 6 is created based on the measurement result of the pitch angle actually measured by actually driving the vehicle 5 (specifically, the actual measurement value of the fluctuation amount of the pitch angle with respect to the acceleration). This is almost equivalent to the characteristic illustrated in FIG. That is, in the fluctuation amount calculation map 40 of FIG. 6, the relationship between the acceleration α and the pitch angle fluctuation amount θpc during acceleration and the relationship between the acceleration α and the pitch angle fluctuation amount θpc during deceleration depend on the actual behavior. As a result, both have different relationships (characteristics).

By calculating the pitch angle variation amount θpc using the variation amount calculation map 40 illustrated in FIG. 6, the pitch angle variation amount θpc can be calculated with higher accuracy. Note that the calculation of the pitch angle variation amount θpc may employ a method different from the processing of S180 to S250 shown in FIG. 5 and the method using the variation amount calculation map described above.

Further, the method of calculating the actual pitch angle θp by adding the pitch angle fluctuation amount θpc and the stopped pitch angle θp0 is just an example. As a result, various calculation methods can be adopted as long as the calculation method uses acceleration and uses different calculation methods depending on whether the vehicle is accelerating or decelerating.

(4) The acceleration α is not limited to a method of calculating by calculation based on a vehicle speed signal (for example, differential calculation of vehicle speed), and may be calculated and acquired by various methods. For example, an acceleration sensor may be provided, and the acceleration α may be calculated based on a detection signal from the acceleration sensor.

(5) In addition, the functions of one component in the above embodiment may be distributed as a plurality of components, or the functions of a plurality of components may be integrated into one component. Further, at least a part of the configuration of the above embodiment may be replaced with a known configuration having the same function. Moreover, you may abbreviate | omit a part of structure of the said embodiment. In addition, at least a part of the configuration of the above embodiment may be added to or replaced with the configuration of the other embodiment. In addition, all the aspects included in the technical idea specified from the wording described in the claims are embodiments of the present invention.

(6) In addition to the headlight control device 1 described above, a system including the headlight control device 1 as a component, a program for causing a computer to function as the headlight control device 1 (specifically, FIG. 5 The present invention can also be realized in various forms such as an optical axis control processing program), a medium on which the program is recorded, and an optical axis control method used in the optical axis control processing.

DESCRIPTION OF SYMBOLS 1 ... Headlamp control apparatus 5 ... Vehicle 10 ... Headlight 11 ... Lamp 12 ... Reflector 13 ... Supporting part 14 ... Movable part 15 ... Motor 20 ... ECU
21 ... CPU
22 ... ROM
23 ... RAM
24 ... Memory for storage 25 ... Input / output circuit 31 ... Inclination sensor 32 ... Vehicle speed sensor 40 ... Variation amount calculation map.

Claims

An acceleration detector (32, 20) for detecting the acceleration of the vehicle (5);
Based on the acceleration detected by the acceleration detection unit, the pitch angle of the vehicle is calculated using a predetermined calculation method using the acceleration, which is different depending on whether the vehicle is accelerating or decelerating. A pitch angle calculation unit (20) to perform,
Control for controlling the optical axis so that the optical axis of the headlamp (10) mounted on the vehicle is directed in a direction corresponding to the pitch angle based on the pitch angle calculated by the pitch angle calculation unit. Part (20);
A vehicle headlamp control device (1) comprising:
The vehicle headlamp control device according to claim 1,
The pitch angle calculation unit calculates a variation amount of the pitch angle caused by the acceleration using the calculation method based on the acceleration detected by the acceleration detection unit, and calculates the calculated variation amount. A vehicle headlamp control device characterized by using the pitch angle to calculate.
The vehicle headlamp control device according to claim 2,
A stopping pitch angle calculation unit (20) that calculates a stopping pitch angle that is the pitch angle in a state where the vehicle is stopped;
The pitch angle calculation unit calculates the pitch angle by adding the fluctuation amount to the stop pitch angle calculated by the stop pitch angle calculation unit. apparatus.
The vehicle headlamp control device according to claim 2 or 3,
The pitch angle calculation unit determines a spring constant for calculation related to the pitch angle corresponding to the acceleration based on the acceleration detected by the acceleration detection unit, and the determined spring constant for calculation The vehicular headlamp control device, wherein the fluctuation amount is calculated by the calculation method using the acceleration.
The vehicle headlamp control device according to claim 4,
The pitch angle calculation unit, based on the acceleration detected by the acceleration detection unit, when the vehicle is accelerating, as a spring constant for the calculation, at least one predetermined spring constant during acceleration When the vehicle is decelerating, any one of at least one predetermined spring constant during deceleration is determined as the spring constant for the calculation. Headlight control device.
The vehicle headlamp control device according to claim 2 or 3,
It is a map in which the acceleration of the vehicle and the amount of variation are associated with each other so that the relationship between the acceleration and the amount of variation during acceleration is different from the relationship between the acceleration and the amount of variation during deceleration. With a set map (40),
The pitch angle calculation unit acquires the variation amount associated with the acceleration in the map based on the acceleration detected by the acceleration detection unit, and calculates the pitch angle using the variation amount. A vehicle headlamp control device characterized by the above.
The vehicle headlamp control device according to any one of claims 1 to 6,
A stable state determination unit (20) for determining whether or not a predetermined acceleration stable state with a small amount of change in the acceleration based on the acceleration detected by the acceleration detection unit;
The vehicle headlamp control device, wherein the pitch angle calculation unit calculates the pitch angle when the stable state determination unit determines that the acceleration is stable.