JP5691892B2 - In-vehicle headlamp optical axis control device - Google Patents

Description

  The present invention relates to an optical axis control device that automatically controls the optical axis angle of an in-vehicle headlamp.

  2. Description of the Related Art Conventionally, an optical axis control device that automatically tilts and adjusts the optical axis angle of an in-vehicle headlamp according to the attitude of a vehicle is known. The headlamp controlled by the optical axis control device incorporates an actuator, and the optical axis angle is adjusted by changing the direction of the light source or reflector in the vertical direction by the actuator. For example, when the number of vehicle occupants increases and the vehicle height decreases and the headlamp irradiation position approaches the road surface, the light beam can reach far by reducing the optical axis angle (Depression angle). Control to ensure the distance is performed. Such an optical axis control device is also called an auto leveling device.

  By the way, this type of optical axis control device includes a dynamic type and a static type. The former controls the optical axis angle in real time in all states including when the vehicle is running. For example, the light irradiation distance is adjusted so as to correspond to a change in posture caused by acceleration / deceleration of the vehicle. However, the dynamic optical axis control apparatus requires a high degree of durability for the components for driving the light source and the reflector in addition to the high frequency of operation of the actuator and high power consumption. Therefore, there is a demerit that costs for manufacturing and maintenance tend to be high, and cost effectiveness is low.

  On the other hand, the latter mainly controls the angle of the optical axis when the vehicle is stopped. For example, the light irradiation distance is adjusted according to the number of passengers and the load when the vehicle is stopped. This static type optical axis control device is less power intensive than the dynamic type because the actuator is operated less frequently, and it is possible to ensure sufficient quality with general-purpose parts for durability. On the other hand, the light irradiation distance is not adjusted when the posture of the vehicle body changes during the traveling of the vehicle, so that it does not reach the dynamic type in terms of convenience.

  In recent years, with the aim of improving the convenience, there has been proposed a static optical axis control device that can adjust the optical axis angle even when the vehicle is not in a stopped state. For example, Patent Document 1 describes that the vibration width of the vehicle body and the engine speed are referred to as conditions for starting the optical axis correction of the headlamp. In this technique, even when the vehicle is traveling, the optical axis correction of the headlamp is started when traveling at a constant speed at a low speed where the vehicle body is not vibrating. As described above, it is possible to improve the convenience while suppressing the cost by determining the traveling state suitable for the optical axis correction of the static headlamp.

JP 2009-248627 A

  However, with the conventional technology as described above, there are cases where it is not possible to correctly grasp the running state suitable for performing optical axis correction of a static headlamp. For example, as described in Japanese Patent Application Laid-Open No. H10-228707, when the traveling state is determined based on the engine speed, the vehicle posture is stable even when the engine rotational speed is high to some extent during constant speed traveling on an expressway. On the other hand, even when the engine speed is low, the vehicle body may be in an unstable posture inclined in the front-rear direction, such as when the vehicle starts or just before it stops. Therefore, it is difficult to correctly determine a state that does not hinder the optical axis correction based on the engine speed.

In addition, the conventional logic may not be able to accurately grasp the vehicle posture when the vehicle is turning. For example, when driving on a highway rampway (a ramp that spirally connects roads with different elevations) at a constant speed, the vehicle's left and right The orientation of the direction may become unstable. Therefore, in order to appropriately perform the optical axis control, it is desired to accurately determine not only the posture of the vehicle in the pitch direction but also the posture in the roll direction.
Thus, the conventional headlamp optical axis control device has a problem that it may be difficult to further improve the accuracy of determination of the running state of the vehicle.

One of the purposes of the present case is to determine a traveling state suitable for performing optical axis correction with high accuracy in an optical axis control device for an in-vehicle headlamp.
The present invention is not limited to this purpose, and is a function and effect derived from each configuration shown in the embodiments for carrying out the invention described later, and other effects of the present invention are to obtain a function and effect that cannot be obtained by conventional techniques. Can be positioned.

(1) An on-vehicle headlamp optical axis control device disclosed herein includes an adjusting unit that adjusts an optical axis angle of an on-vehicle headlamp in a vertical direction, and a driving torque calculating unit that calculates a driving torque acting on driving wheels of a vehicle. With. Further, a resistance torque calculating means for calculating a resistance torque during traveling of the vehicle, a roll angle calculating means for calculating a roll angle during traveling of the vehicle, and a pitch influence torque obtained by subtracting the resistance torque from the driving torque. And a pitch influence torque calculating means for calculating . Furthermore, a determination unit is provided for determining whether the vehicle is in a static traveling state or a dynamic traveling state based on the driving torque, the resistance torque, and the roll angle.
In addition, when the determination unit determines that the vehicle is in the static running state, the adjustment unit permits the adjustment of the optical axis angle, and when the determination unit determines that the vehicle is in the dynamic running state, the adjustment is performed. The control means to prohibit is provided.
The discriminating means has a value of the roll angle within a predetermined range (first predetermined range) set in advance and a value of the pitch influence torque within a predetermined range (second predetermined range). Is determined to be in the static running state, and in other cases, it is determined to be in the dynamic running state.

  Here, the “static running state” means a state where the running is continued while the postures of the vehicle in the pitch direction and the roll direction are substantially maintained at the postures when the vehicle is stopped. The “dynamic running state” means a running state other than the “static running state”, and means a running state in which the posture of the vehicle in the pitch direction or the posture in the roll direction is not necessarily maintained at the posture when the vehicle is stopped. Both of these are one of the traveling states of the vehicle, and the stopped state of the vehicle is not included in these states.

( 2 ) Moreover, it is preferable that the said roll angle calculating means calculates the said roll angle based on the steering angle, vehicle speed, and yaw rate of the said vehicle.
( 3 ) Moreover, it is preferable that the said resistance torque calculating means calculates the said resistance torque based on the vehicle speed of the said vehicle.

( 4 ) Further, it is preferable that the driving torque calculating means calculates the driving torque based on a speed ratio between the engine and the driving wheels and an engine torque output from the engine. For example, in an automobile or a hybrid vehicle in which a transmission is interposed between the engine and the driving wheel, the transmission ratio is grasped based on the operating state of the transmission.
( 5 ) Moreover, it is preferable that the said drive torque calculating means calculates the said drive torque based on the motor torque output from the motor for driving | running | working. For example, in an electric vehicle having no transmission, the driving torque is grasped based on the motor torque.

( 6 ) Alternatively, it is preferable that the driving torque calculating means calculates the driving torque based on a speed ratio between the traveling motor and the driving wheels and the motor torque. For example, in an electric vehicle in which a transmission is interposed between the traveling motor and the driving wheel, the driving torque is grasped based on the transmission ratio and the motor torque.

According to the disclosed on-vehicle headlamp optical axis control device, the range of pitch influence torque ( torque obtained by subtracting the resistance torque from the driving torque of the driving wheel ) is set as the determination condition for permitting or prohibiting the adjustment of the optical axis angle. In addition to this, by using the range of the roll angle of the vehicle, it is possible to estimate the change in posture in the pitch direction and the change in posture in the roll direction with high accuracy, and to achieve a driving state suitable for optical axis correction. It can be determined with high accuracy.
For example, the determination accuracy of the traveling state can be improved as compared with the method of determining the traveling state using the engine speed. As a result, it is possible to extend the life of the parts related to the adjustment of the optical axis angle, and to improve the balance between cost and convenience.

1 is a side view schematically showing a vehicle to which an optical axis control device according to an embodiment is applied. FIG. 2 is a block diagram illustrating a configuration of an optical axis control device in FIG. 1. It is a block diagram for demonstrating the calculation content in the optical axis control apparatus of FIG. It is a graph for demonstrating the control content in the optical axis control apparatus of FIG. 3 is a flowchart illustrating a control procedure in the optical axis control device of FIG. 1.

  The control device will be described with reference to the drawings. Note that the embodiment described below is merely an example, and there is no intention to exclude various modifications and technical applications that are not explicitly described in the following embodiment. In addition, each configuration of the following embodiment can be selected as necessary, or may be appropriately combined, and various modifications can be made without departing from the spirit of the embodiment.

[1. Device configuration]
The on-vehicle headlamp optical axis control device of this embodiment is mounted on a vehicle 10 shown in FIG. The vehicle 10 is a gasoline vehicle that travels using the engine 7 as a drive source. The driving force generated by the engine 7 is transmitted to the driving wheels among the wheels 11 via the transmission 9 and a power transmission path (not shown).
A pair of left and right headlamps 5 is provided at the front portion of the vehicle 10. Each headlamp 5 incorporates an actuator 6 (adjustment means) for adjusting the light irradiation direction up and down, and tilts and adjusts the optical axis angle according to the attitude of the vehicle 10.

  For example, as schematically shown in FIG. 2, a reflector 5b arranged around the light source 5a of the headlamp 5 is provided so as to be swingable in the vertical direction. The direction of the swing central shaft 5c of the reflector 5b is the vehicle width direction of the vehicle 10. The tip of the rod 6a of the actuator 6 that expands and contracts in the horizontal direction (vehicle longitudinal direction) is pin-bonded to the reflector 5b. With such a structure, the reflector 5b swings according to the amount of expansion and contraction of the rod 6a in the horizontal direction, and the optical axis angle is adjusted in the vertical direction. The actuator 6 that drives the rod 6a is controlled by the optical axis controller 1 described later.

  The actuator 6 according to the present embodiment is an adjusting unit that adjusts the optical axis angle not only when the vehicle 10 is stopped but also during traveling. However, the optical axis angle is not adjusted in an unlimited manner while the vehicle 10 is traveling, but is controlled so as to adjust the optical axis angle only in a traveling state suitable for performing optical axis correction.

  The vehicle 10 is provided with an optical axis control device 1 and an engine control device 8 as electronic control devices for controlling the engine 7 and the headlamp 5 described above. These control devices are configured as LSI devices or embedded electronic devices in which a microprocessor, ROM, RAM, and the like are integrated, for example, and are connected to each other via communication lines such as CAN and FlexRay provided in the vehicle 10. These control devices are energized when an operation position of an ignition switch (not shown) is an accessory position or an ON position (a position corresponding to a state where the engine 7 is started), and start various controls.

  The engine control device 8 is an electronic control device that controls a wide range of systems such as an ignition system, a fuel system, an intake / exhaust system, and a valve system related to the engine 7. It controls the amount of air to be introduced, the amount of fuel injection, and the ignition timing. Further, the engine 7 is provided with an engine speed sensor 16 for detecting the engine speed Ne, and information on the engine speed Ne detected here is transmitted to the optical axis control device 1 and the engine control device 8. ing.

Inside the engine control device 8, a predetermined calculation method based on an accelerator operation amount θ _AC detected by an accelerator sensor 15 described later, a wheel speed Vt detected by a wheel speed sensor 14, a fuel injection amount, an engine speed Ne, and the like. Thus, the value of the engine torque Te output from the engine 7 is calculated at any time. The engine torque Te is, for example, a torque value output from the output shaft of the engine 7 and is a torque input from the engine 7 to the transmission 9. The value of the engine torque Te calculated here is transmitted to the optical axis control device 1. Note that the value of the engine torque Te is also used for actual control of the engine 7.

  The optical axis control device 1 is an electronic control device that controls the light amount, light distribution state, optical axis angle, and the like of the headlamp 5. On the input side of the optical axis control device 1, as shown in FIG. 2, the engine control device 8, the door sensor 12, the height sensor 13, the wheel speed sensor 14, the accelerator sensor 15, the steering angle sensor 19, and the yaw rate sensor 20 described above. Is connected.

  The door sensor 12 is an open / close sensor provided in each door 17 on both side surfaces of the vehicle 10, and detects the open / close state of each door 17 and outputs an open / close signal P corresponding thereto. . These opening / closing signals P are transmitted to the optical axis control device 1.

  The height sensor 13 is a sensor attached to the suspension device that suspends the wheel 11 from the vehicle body, and detects the vehicle height H corresponding to the amount of expansion and contraction of the suspension spring 18. Although FIG. 1 illustrates an example in which only one height sensor 13 is provided in the suspension device for the rear wheel of the vehicle 10, the height sensor 13 may be provided in each of the suspension devices for both the front wheel and the rear wheel.

  The vehicle height H detected by the height sensor 13 is a parameter corresponding to the height from the ground at the position where the height sensor 13 is provided, in other words, a parameter corresponding to the degree of inclination of the vehicle 10. The fluctuation of the vehicle height H corresponds to the vibration of the vehicle body, and the larger the vibration, the larger the amplitude of the vehicle height H and the fluctuation frequency (frequency). Information on the vehicle height H detected here is transmitted to the optical axis control device 1 as an index for grasping the posture and vibration state of the vehicle 10.

  The wheel speed sensor 14 detects (or calculates) the rotation angle of the axle supporting the wheel 11 and its angular speed. The amount of change in the rotation angle of the axle per unit time is proportional to the rotational speed of the wheel 11, and if no slip occurs, the rotational speed of the wheel 11 is proportional to the wheel speed Vt (vehicle speed). Information on the wheel speed Vt detected (or calculated) here is transmitted to the optical axis control device 1 and the engine control device 8. The wheel speed Vt may be calculated by the optical axis control device 1 based on the rotation angle of the axle detected by the wheel speed sensor 14.

The accelerator sensor 15 is a stroke sensor that detects an operation amount θ _AC (accelerator operation amount) corresponding to the depression amount of the accelerator pedal. The accelerator operation amount θ _AC is a parameter corresponding to the driver's acceleration request, that is, corresponds to an output request to the engine 7. Information on the accelerator operation amount θ _AC detected here is transmitted to the optical axis control device 1 and the engine control device 8.

The steering angle sensor 19 is a sensor that detects the steering angle θ _ST of the steering (or the steering angle of the steering wheel). The yaw rate sensor 20 detects the yaw rate Y acting on the vehicle 10. The yaw rate Y is the rotational speed of the vehicle 10 around the vertical axis (angular speed of rotational movement in a horizontal plane). Information on the steering angle θ _ST and the yaw rate Y detected by these sensors is transmitted to the optical axis control device 1.

[2. Control configuration]
[2-1. Overview of control]
The actuator 6 is connected to the output side of the optical axis control device 1. The optical axis control device 1 of the present embodiment performs optical axis control of the headlamp 5 based on the input information. The optical axis control here refers to automatically tilting the optical axis angle (the depression angle) of the headlamp 5 by controlling the operation amount of the actuator 6 (the expansion and contraction operation amount of the rod 6a) according to the attitude of the vehicle 10. It is control to adjust.

Specifically, the pitch angle θ _p (tilt in the front-rear direction) of the vehicle 10 is estimated based on the vehicle height H detected by the height sensor 13, and the irradiation distance is secured according to the pitch angle θ _p. In this control, the rod 6a of the actuator 6 is driven. For example, assuming that the vehicle 10 is stopped on a horizontal road surface as a reference state, the optical axis angle is decreased as the pitch angle θ _p increases, and the optical axis angle is increased as the pitch angle θ _p decreases. The actuator 6 is driven. In other words, the rod 6a of the actuator 6 is driven so that the irradiation direction is upward as the tendency of the forward leaning posture is increased and the irradiation direction is downward as the tendency of the backward leaning posture is increased.

In the present embodiment, the state of the vehicle 10 is classified into the following three types. The optical axis control device 1 performs optical axis control when it is in the following state (1) or (2).
(1) The vehicle 10 is in a stopped state (stopped) (2) The vehicle 10 is traveling and is in a static traveling state (3) The vehicle 10 is traveling and is in a dynamic traveling state

  The above (1) includes, for example, the idling stop time immediately after the engine 7 is started. In addition, when the vehicle 10 once stops running (for example, when a signal is temporarily stopped), it is considered that the posture of the vehicle 10 does not change because there is no change in the number of passengers or cargo. Therefore, it may be in a state not included in the above (1) (a state in which optical axis control is not performed).

The above (2) includes, for example, traveling at a constant vehicle speed (during constant speed traveling or autocruising). The static running state means a state where the running is continued while the postures of the vehicle 10 in the pitch direction and the roll direction are substantially maintained at the postures when the vehicle is stopped. In other words, compared to when the vehicle is stopped, the postures in the pitch direction and the roll direction with respect to the traveling road surface are almost the same, and the postures do not change dynamically, and a certain amount of time is maintained. When the driving state is relatively stable, the optical axis angle is adjusted.
On the other hand, said (3) respond | corresponds to driving states other than (2). That is, the optical axis angle is not adjusted when the vehicle 10 is in a relatively unstable running state in which the attitude of the vehicle 10 is dynamically changing.

[2-2. Control block configuration]
As shown in FIG. 2, the optical axis control device 1 includes a calculation unit 2, a determination unit 3, and a control unit 4. Each function of the calculation unit 2, the determination unit 3, and the control unit 4 may be realized by an electronic circuit (hardware), may be programmed as software, or one of these functions. The part may be provided as hardware and the other part may be software.

  The calculation unit 2 performs calculations related to the optical axis control described above, and includes a gear ratio calculation unit 2a, a drive torque calculation unit 2b, a resistance torque calculation unit 2c, a pitch influence torque calculation unit 2d, a moving distance calculation unit 2e, and the like. A roll angle calculation unit 2f is provided. FIG. 3 schematically shows the flow of parameters calculated by each calculation unit.

  The gear ratio calculation unit 2a calculates the gear ratio R between the engine 7 and the drive wheels. The speed ratio R is a parameter corresponding to the ratio of the driving torque Td of the driving wheels to the engine torque Te, and corresponds to the gear ratio of the transmission 9. Here, the gear ratio R is calculated based on the ratio of the engine speed Ne and the wheel speed Vt. Information of the speed ratio R calculated here is transmitted to the drive torque calculation unit 2b. Note that when the engine control device 8 knows the operating state of the transmission 9, information on the gear ratio R may be received from the engine control device 8.

The drive torque calculator 2b (drive torque calculator) calculates the drive torque Td of the vehicle 10, that is, the drive torque Td acting on the drive wheels. Here, the drive torque Td of the vehicle 10 is calculated based on the engine torque Te transmitted from the engine control device 8 and the speed ratio R transmitted from the speed ratio calculation unit 2a. The value of the drive torque Td is calculated according to the following formula 1, for example. The value of the drive torque Td calculated here is transmitted to the pitch influence torque calculation unit 2d.
(Drive torque Td) = (Engine torque Te) × (Speed change ratio R) (Formula 1)

  The resistance torque calculation unit 2c (resistance torque calculation means) calculates the resistance torque Tr when the vehicle 10 is traveling. The resistance torque Tr means a decrease in torque depending on the traveling speed of the vehicle 10, and the torque that tries to move the vehicle 10 in the direction opposite to the driving torque Td due to air resistance, frictional resistance of the wheels 11, and the like. It corresponds to. Here, the resistance torque Tr is calculated based on the wheel speed Vt. For example, the value of the resistance torque Tr is calculated based on a calculation model in which the resistance increases in proportion to the square of the wheel speed Vt. The value of the resistance torque Tr calculated here is transmitted to the pitch influence torque calculation unit 2d.

The pitch influence torque calculation unit 2d (pitch influence torque calculation means) calculates the pitch influence torque Tp that affects the pitch angle θ _{p of the} vehicle 10 (the attitude of the vehicle 10 in the pitch direction). Here, according to the following formula 2, a value obtained by subtracting the resistance torque Tr from the driving torque Td is calculated as the pitch influence torque Tp. The value of the pitch influence torque Tp calculated here is transmitted to the determination unit 3.
(Pitch influence torque Tp) = (Drive torque Td) − (resistance torque Tr) (Formula 2)

The pitch angle θ _p of the vehicle 10 is a parameter that depends on the longitudinal acceleration acting on the vehicle 10. For example, if the acceleration in the front-rear direction is the same, the pitch angle θ _p of the vehicle 10 is the same even when the vehicle 10 is traveling on a downhill road or during acceleration. On the other hand, the longitudinal acceleration depends on the magnitude of the pitch influence torque Tp obtained by subtracting the resistance torque Tr from the drive torque Td. Therefore, by referring to the pitch influence torque Tp, it is possible to accurately estimate the pitch angle θ _p regardless of the traveling state of the vehicle 10 and the road surface gradient, that is, it is possible to accurately estimate the attitude of the vehicle 10. It becomes possible.

  The movement distance calculation part 2e calculates the movement distance L of the vehicle 10 based on the wheel speed Vt. The moving distance L here is the distance that the vehicle 10 has moved from the position when the ignition switch of the vehicle 10 is turned on. However, when any door 17 of the vehicle 10 is opened, the moving distance L is reset. The travel distance L corresponds to the distance traveled in a state where the number of passengers and the load affecting the posture of the vehicle 10 do not change.

Here, for example, the movement distance L is cumulatively calculated based on the previous value L ′ of the movement distance obtained in the previous calculation cycle according to the following Expression 3. In Equation 3, k is a predetermined coefficient, and k · Vt corresponds to the moving distance of the vehicle 10 from the previous calculation cycle. Therefore, when the vehicle 10 is stopped, the value of the movement distance L does not change. Information on the movement distance L calculated here is transmitted to the determination unit 3.
(Movement distance L) = (Previous value L ') + k · Vt (Equation 3)

The roll angle calculation unit 2f (roll angle calculation means) calculates the roll angle θ _{y of the} vehicle 10 (the posture of the vehicle 10 in the roll direction). The roll angle θ _y is a parameter that depends on the lateral acceleration G _y (lateral acceleration) acting on the vehicle 10. If the weight of the vehicle 10 is constant, the roll angle θ _y is described as a function of the lateral acceleration G _y. can do. Further, the lateral acceleration G _y acting on the vehicle 10, turning radius, a magnitude corresponding to the running speed and yaw rate of the vehicle. Using such characteristics, the roll angle calculation unit 2f calculates the roll angle θ _y based on the steering angle θ _ST detected by the steering angle sensor 19, the yaw rate Y detected by the yaw rate sensor 20, the wheel speed Vt, and the like. Calculate. Information on the roll angle θ _y calculated here is transmitted to the determination unit 3.

Although the specific calculation method of the lateral acceleration G _y is arbitrary, the steering angle θ _ST [rad], wheel speed Vt [m / s], turning radius Z [m], and yaw rate Y [rad / s] If the lateral acceleration G _y [m / s ² ] is expressed by using it, it can be obtained by the following equations 4 to 6.
(Lateral acceleration G _y ) = (wheel speed Vt) × (yaw rate Y) (Formula 4)
(Yaw rate Y) = (wheel speed Vt) / (turning radius Z) (Formula 5)
(Turning radius Z) = {(constant Ca) − (constant Cb) × (wheel speed Vt) ² } / (steering angle θ _ST ) (Expression 6)

Therefore, the lateral acceleration G _y may be obtained from Equation 4 using the wheel speed Vt and the yaw rate Y detected from the yaw rate sensor 20. Further, the lateral acceleration G _y may be obtained from Equation 4 using the yaw rate Y calculated from Equation 5 and Equation 6 using the wheel speed Vt and the steering angle θ _ST . Further, the lateral acceleration G _y the equation 4 to equation 6 and be dependent on the wheel speed Vt and the steering angle theta _ST, since the roll angle theta _y depends on the lateral acceleration G _y, roll angle theta _y and the wheel The relationship between the speed Vt and the steering angle θ _ST may be mapped and expressed in advance, and these maps and mathematical expressions may be stored in advance in the roll angle calculation unit 2f.

  The discriminating unit 3 (discriminating means) discriminates whether the vehicle 10 is in a static running state or a dynamic running state based on the pitch affecting torque Tp calculated by the pitch affecting torque calculating unit 2d. That is, it is determined here whether the traveling state of the vehicle 10 is (2) or (3). The determination unit 3 stores in advance a map, an arithmetic expression, and the like that define a correspondence relationship between the value of the pitch influence torque Tp and the state of the vehicle 10, and the state of the vehicle 10 is determined using these maps, the arithmetic expression, and the like. Determine.

For example, as shown in FIG. 4, when the pitch influence torque Tp exceeds a predetermined positive value Tmax or is less than a predetermined negative value Tmin, it is determined that the traveling state of the vehicle 10 is a dynamic traveling state. To do. Similarly, when the roll angle theta _y is less than a predetermined negative or when predetermined exceeding a positive angle θmax angle θmin is traveling state of the vehicle 10 is determined to be dynamic running state.

On the other hand, the pitch effect torque Tp is within the range of less Tmax above Tmin, and, when the roll angle theta _y falls within the following ranges θmax above θmin is determined to be a static traveling state. In FIG. 4, an area where the vehicle 10 is determined to be in a static running state is a hatched area. The positive torque corresponds to the force that drives the vehicle 10 in the forward direction, and the negative torque corresponds to the force that drives the vehicle 10 in the backward direction. The traveling state of the vehicle 10 determined here is transmitted to the control unit 4.

The control unit 4 (control means) performs optical axis control based on the movement distance L calculated by the movement distance calculation unit 2e, the opening / closing signal P from the door sensor 12, the determination result by the determination unit 3, and the like. It is.
First, when the vehicle is stopped and the moving distance L is L = 0, the state of the vehicle 10 corresponds to the above (1), so the control unit 4 performs optical axis control. For example, when the ignition switch is operated to the accessory position or when idling stops immediately after the engine 7 is started, auto-leveling is performed according to the change in the posture of the vehicle 10.

  Further, even when the vehicle 10 is stopped, if the moving distance L is not L = 0, the optical axis control is not performed. For example, in a state where the vehicle 10 is temporarily stopped to wait for a signal at the intersection after starting, the posture of the vehicle 10 is considered not to have changed from the posture at the time of stopping before starting, so the optical axis control is prohibited. The actuator 6 is maintained in a stopped state.

On the other hand, when the vehicle is traveling, the optical axis control is performed when the traveling state of the vehicle 10 is the static traveling state, and the optical axis control is prohibited when the traveling state is the dynamic traveling state. That is, auto leveling is performed when the state of the vehicle 10 is (2), and auto leveling is not performed when the state is (3).
When the optical axis control starts, the pitch angle θ _p of the vehicle 10 is estimated and calculated based on the vehicle height H detected by the height sensor 13, and a drive signal is sent from the control unit 4 to the actuator 6 according to the pitch angle θ _p. Is output. Thereby, the optical axis angle of the headlamp 5 is automatically tilted and the irradiation distance of light is ensured.

[3. flowchart]
[3-1. Calculation of moving distance]
FIG. 5 is a schematic flowchart for explaining a procedure of optical axis control executed by the optical axis control device 1. The control shown in this flowchart is started when the ignition switch of the vehicle is operated to the accessory position or the on position and the optical axis control device 1 is energized, and is set in a predetermined cycle (for example, several tens [ms]) Cycle). In this embodiment, the initial setting value of the movement distance L integrated by the optical axis control device 1 is L = 0, and the value of the movement distance L of the movement distance calculation unit 2e is reset at the start of this flow. .

In step S10, information from various sensors connected to the input side of the optical axis control device 1 is read. For example, the opening / closing signal P from the door sensor 12, the information on the wheel speed Vt from the wheel speed sensor 14, the information on the vehicle height H from the height sensor 13, the information on the steering angle θ _ST from the steering angle sensor 19, the yaw rate sensor 20 The information on the yaw rate Y from the engine, the engine torque Te from the engine control device 8, the information on the engine speed Ne from the engine speed sensor 16, and the like are input to the optical axis control device 1. Note that the values of the engine torque Te and the engine speed Ne when the engine 7 is not started are both zero.

  In step S12, based on the opening / closing signal P from the door sensor 12, it is determined whether any door 17 of the vehicle 10 is open. If there is an open door 17, the process proceeds to step S 14, and the movement distance calculation unit 2 e resets the movement distance L to L = 0. If all the doors 17 are closed, the process proceeds to step S 16 and moves to the movement distance. The integrated value of the movement distance L is calculated by the calculation unit 2e.

[3-2. Control without driving torque]
In step S18, it is determined whether the drive torque Td is generated (Td ≠ 0) or not (Td = 0). Here, for example, it is determined whether or not the engine torque Te is zero. When the engine torque Te of the engine 7 is Te = 0, the drive torque Td is not generated, so the process proceeds to step S20. On the other hand, when the engine 7 is started (during idling, normal running, etc.), Te ≠ 0, that is, the drive torque Td is generated, so the process proceeds to step S28. The presence or absence of the drive torque may be determined using the engine speed Ne instead of the engine torque Te. Further, in consideration of calculation error and control error, the determination threshold value of the engine torque Te may be an arbitrary constant instead of 0.

  In step S20, it is determined whether or not the vehicle body is oscillating based on the variation in the vehicle height H. For example, it is determined that the vehicle body is vibrating when the amplitude (or vibration frequency) of the temporal variation of the vehicle height H is greater than or equal to a predetermined value, and the process proceeds to step S44. On the other hand, when it is determined that the vehicle body is not oscillating, it is considered that the vehicle posture is stable and the process proceeds to step S22.

In step S22, the pitch angle θ _p of the vehicle 10 is estimated based on the vehicle height H, and the drive target value of the actuator 6 is calculated according to the pitch angle θ _p . In the subsequent step S24, a drive signal corresponding to the drive target value is output to the actuator 6, and the optical axis angle of the headlamp 5 is automatically tilt-adjusted.

[3-3. Control with drive torque (when the vehicle is stopped)]
When it is determined in step S18 that the drive torque Td is generated, the process proceeds to step S28, and it is determined whether or not the moving distance L of the vehicle 10 calculated by the moving distance calculation unit 2e is L = 0. The Here, L = 0 is, for example, immediately after the engine 7 is started or when any one of the doors 17 is opened, and is limited to a state where the vehicle 10 has not started yet. Therefore, if the movement distance L is L = 0, it is determined that the vehicle 10 is stopped, and the process proceeds to step S30. On the other hand, when L ≠ 0, it is determined that the vehicle 10 is traveling, and the process proceeds to step S32. In the determination in step S28, an arbitrary constant may be used as the determination threshold value for the movement distance L instead of 0.

In step S30, it is determined whether or not the accelerator is in an open state based on the information on the accelerator operation amount θ _AC detected by the accelerator sensor 15. For example, when θ _AC = 0, the process proceeds to step S20, and when θ _AC ≠ 0, the process proceeds to step S44. As with the movement distance L, an arbitrary constant may be used as the determination threshold value for the accelerator operation amount θ _AC instead of 0.

  If it is determined in steps S28 to S30 that the accelerator pedal is depressed even when the vehicle 10 is stopped, the process proceeds to step S44. In step S44, the optical axis control is not performed, that is, the actuator 6 is not driven and adjustment of the optical axis angle is prohibited. Therefore, the optical axis control is performed when the vehicle 10 is stopped only when the vehicle 10 is stopped in a stable vehicle posture.

[3-4. Control with drive torque (when driving)]
If it is determined in step S28 that the vehicle 10 is traveling, the process proceeds to step S32, and the value of the drive torque Td is calculated. At this time, the gear ratio calculating unit 2a calculates the gear ratio R from the engine speed Ne and the wheel speed Vt, and the value of the gear ratio R is transmitted to the drive torque calculating unit 2b. On the other hand, in the drive torque calculation unit 2b, a value obtained by multiplying the gear ratio R by the engine torque Te is calculated as the drive torque Td.

  In the subsequent step S34, the value of the resistance torque Tr is calculated. Here, the resistance torque Tr is calculated based on the wheel speed Vt by the resistance torque calculator 2c. In the subsequent step S36, a value obtained by subtracting the resistance torque Tr from the drive torque Td by the pitch influence torque calculation unit 2d is calculated as the pitch influence torque Tp.

  In step S38, the determination unit 3 determines whether or not the pitch influence torque Tp is in the range of Tmin or more and Tmax or less. Here, if Tmin ≦ Tp ≦ Tmax, the process proceeds to step S40, and the traveling state of the vehicle is continuously determined. On the other hand, when Tmin ≦ Tp ≦ Tmax is not satisfied, it is determined that the vehicle 10 is in the dynamic running state, and the process proceeds to step S44. That is, in this case, it is determined that the vehicle 10 is in a relatively unstable traveling state in which the posture in the pitch direction is dynamically changing, and the optical axis control is prohibited.

At step S40, the value of the roll angle theta _y is calculated by the roll angle calculating section 2f. Here, the roll angle θ _y is calculated based on the steering angle θ _ST , the wheel speed Vt, and the yaw rate Y, and is transmitted to the determination unit 3. In step S42, whether the roll angle theta _y is in the range of less than and .theta.max .theta.min in the determining unit 3 is determined. Here, if θmin ≦ θ _y ≦ θmax, it is determined that the vehicle 10 is in a static running state, and the process proceeds to step S22. That is, it is determined that the posture of the vehicle 10 in the pitch direction and the roll direction is maintained at the time of stopping, and the vehicle 10 is in a stable running state, and optical axis control is performed.

On the other hand, when θmin ≦ θ _y ≦ θmax is not satisfied, it is determined that the vehicle 10 is in the dynamic running state, and the process proceeds to step S44. That is, in this case, it is determined that the vehicle 10 is in a relatively unstable traveling state in which the posture in the roll direction is dynamically changing, and the optical axis control is prohibited.

[4. effect]
In the on-vehicle headlamp optical axis control device 1 described above, when determining the optical axis control start condition, the traveling state of the vehicle 10 is recognized by distinguishing between a stationary traveling state and a dynamic traveling state. The static running state and the dynamic running state are determined based on whether or not the posture in the pitch direction and the posture in the roll direction of the vehicle 10 are both stably maintained. For determining the posture in the pitch direction, the values of the driving torque Td and the resistance torque Tr acting on the driving wheel are used, and for determining the posture in the roll direction, the value of the roll angle θ _y is used.

Thus, by using the driving torque Td of the drive wheel to the determination condition for permitting or prohibiting the adjustment of the optical axis angle, the resistance torque Tr and the roll angle theta _y, the vehicle 10 suitable for performing the optical axis correction Can be determined with high accuracy.
For example, it is difficult to determine the state of high-speed constant speed driving (auto cruise) with the state determination method at the time of traveling using the engine speed Ne, but the method of this embodiment is a kind of static traveling state. The state of high-speed constant speed traveling can be accurately determined, and the state determination accuracy can be improved.

Further, by referring to both the value of the driving torque Td and the value of the resistance torque Tr, which is a decrease in torque depending on the traveling speed of the vehicle 10, regardless of the traveling state of the vehicle 10 or the road surface gradient, the vehicle 10 It is possible to accurately estimate the running state. It is also possible to determine with high accuracy a running state in which the posture in the pitch direction can be changed at a low speed as when traveling on an uphill road or a downhill road. In addition to this, since the roll angle θ _y is referred to in the method of the present embodiment, for example, a change in posture in the roll direction that can increase when traveling on a rampway on a highway at a constant speed is highly accurate. It is also possible to estimate to.

  Therefore, it is possible to improve the determination accuracy of the traveling state in which the optical axis correction can be performed without imposing an excessive burden on the actuator 6, and light that further improves convenience while reducing the cost of the headlamp 5. Axis control can be implemented. In addition, the lifetime of parts such as the actuator 6 relating to the adjustment of the optical axis angle can be extended, and a good cost-effectiveness can be obtained by improving the balance between cost and convenience.

Further, in the above-described in-vehicle headlamp optical axis control device 1, when the value of the roll angle θ _y is θmin ≦ θ _y ≦ θmax, it is determined that the traveling state of the vehicle 10 is the static traveling state. That is, by limiting the range of the value of the roll angle θ _y determined to be a static running state to a predetermined range, a device that detects a roll angle, a device that detects acceleration (gravity acceleration, longitudinal acceleration, lateral acceleration, etc.), etc. The influence given to the attitude | position of the roll direction of the vehicle 10 can be considered without using, and the discrimination | determination precision of a driving | running | working state can be improved.

  Further, in the above-described in-vehicle headlamp optical axis control device 1, the pitch influence torque Tp is calculated through the calculation of subtracting the resistance torque Tr from the drive torque Td, and the value of the pitch influence torque Tp is Tmin ≦ Tp ≦ Tmax. It is determined that the traveling state of the vehicle 10 is the stationary traveling state. That is, by limiting the range of the value of the pitch influence torque Tp determined to be the static running state to a predetermined range, the influence given to the posture of the vehicle 10 in the pitch direction can be considered without using the vehicle speed, the road surface gradient, or the like. It is possible to improve the determination accuracy of the running state.

Furthermore, since the pitch influence torque Tp becomes a value corresponding to the pitch angle θ _p regardless of the traveling state of the vehicle 10 and the road surface gradient, the determination accuracy of the traveling state of the vehicle 10 can be remarkably improved. In addition, a change in posture due to acceleration / deceleration of the vehicle 10 and a change in posture due to road surface gradient can be determined with high accuracy using the same logic, and the calculation configuration can be simplified. Thereby, the reliability of control can be improved.

In the optical axis control device 1 of the above vehicle headlamp, a steering angle theta _ST, and calculates the roll angle theta _y based on the wheel speed Vt and the yaw rate Y, the roll angle with high accuracy by using a simple configuration theta _y There is an advantage that the determination accuracy of the traveling state of the vehicle 10 can be improved.

  In addition, since the resistance torque Tr is calculated based on the wheel speed Vt when calculating the pitch influence torque Tp, the vehicle 10 is traveling at a high speed as in, for example, high speed constant speed driving (during auto cruise). It is possible to determine the posture in consideration of the effect of air resistance, and it is possible to grasp the value of the pitch influence torque with high accuracy, and to improve the optical axis controllability during traveling.

  Further, in the above-described in-vehicle headlamp optical axis control device 1, the drive torque Td is calculated based on the engine torque Te and the gear ratio R in the drive torque calculator 2b. As described above, the value of the drive torque Td acting on the drive wheels can be grasped with high accuracy by the calculation based on the engine torque Te and the gear ratio R. Accordingly, it is possible to improve the determination accuracy of the traveling state of the vehicle 10 (for example, a gasoline vehicle) that travels using the engine 7 as a power source.

[5. Modified example]
In the above-described embodiment, an example in which the optical axis control device 1 is applied to a gasoline vehicle using the engine 7 as a drive source is illustrated, but an electric vehicle or a drive using a drive motor (such as an electric motor or a motor generator) as a drive source. Application to a hybrid vehicle using both a motor and an engine 7 and a diesel vehicle is also possible. When the optical axis control device 1 is applied to an electric vehicle, the driving torque Td of the vehicle 10 may be calculated based on the value of the motor torque Tm output from the traveling motor.

For example, the transmission ratio calculation unit 2a calculates a rotation ratio (transmission ratio) between the traveling motor and the drive wheels, and the drive torque calculation unit 2b multiplies the rotation ratio by the motor torque Tm to obtain the drive torque Td. It can be considered. Motor torque Tm is A configuration may be received from the electronic control unit for controlling the traction motor, based on the depression amount of the accelerator operation amount theta _AC and the brake pedal detected by the accelerator sensor 15, the wheel speed Vt information, etc. Then, it may be calculated in the drive torque calculation unit 2b. Some electric vehicles do not include a transmission between the driving motor and the drive wheels. In this case, the rotation ratio (transmission ratio) may be set to 1, and the motor torque Tm is set to the drive torque. You may calculate as Td.

  Thus, the calculation based on the motor torque Tm (or the calculation based on the motor torque Tm and the rotation ratio) makes it possible to grasp the value of the driving torque Td with high accuracy, and consequently the value of the pitch influence torque Tp. Can be grasped with high accuracy. Therefore, even in a vehicle that travels using the traveling motor as a power source, it is possible to improve the determination accuracy of the traveling state.

In the case of a hybrid vehicle, the sum of the torque on the engine side and the torque on the traveling motor side may be calculated by the drive torque calculator 2b as the drive torque Td.
Moreover, in the above-described embodiment, the values Tmax and Tmin, which are the determination threshold values for the static running state, are exemplified as positive and negative, respectively. However, specific settings of these values Tmax and Tmin are arbitrary. is there. In addition, since it is considered that the state where the drive torque Td is Td = 0 is the most stable running state, 0 (or a minute value close to 0) is included in the range of the driving torque Td determined as the static running state. It is preferable that

DESCRIPTION OF SYMBOLS 1 Optical axis control apparatus 2 Calculation part 2a Gear ratio calculation part 2b Drive torque calculation part (drive torque calculation means)
2c Resistance torque calculation unit (resistance torque calculation means)
2d Pitch influence torque calculation section (pitch influence torque calculation means)
2e Movement distance calculation unit 2f Roll angle calculation unit (roll angle calculation means)
3 Discriminator (discriminating means)
4 Control unit (control means)
5 Headlamp 6 Actuator (Adjustment means)

Claims (6)

Adjusting means for adjusting the optical axis angle of the in-vehicle headlamp in the vertical direction;
Drive torque calculation means for calculating drive torque acting on the drive wheels of the vehicle;
A resistance torque calculating means for calculating a resistance torque during travel of the vehicle;
A roll angle calculating means for calculating a roll angle during travel of the vehicle;
Pitch affecting torque calculating means for calculating a pitch affecting torque obtained by subtracting the resistance torque from the driving torque;
Discrimination means for discriminating whether the vehicle is in a static running state or a dynamic running state based on the driving torque, the resistance torque, and the roll angle;
The adjustment means permits the adjustment of the optical axis angle when the vehicle is determined to be in the static running state, and prohibits the adjustment when the vehicle is determined to be in the dynamic running state. Control means ,
The determination means is in the static running state when the value of the roll angle exists within a predetermined range set in advance and the value of the pitch influence torque exists within a predetermined range set up in advance. An optical axis control device for an in-vehicle headlamp, characterized in that it is determined and otherwise determined as the dynamic running state . The roll angle calculating means, the steering angle of the vehicle, characterized by calculating said roll angle based on the vehicle speed and the yaw rate, the optical axis control unit of the in-vehicle headlamp of claim 1, wherein. The optical axis control device for an in-vehicle headlamp according to claim 1 or 2 , wherein the resistance torque calculation means calculates the resistance torque based on a vehicle speed of the vehicle. The driving torque calculating means, and the gear ratio between the engine and the driving wheels, on the basis of the engine torque output from the engine, characterized by calculating the drive torque, one of claims 1 to 3 An optical axis control device for an in-vehicle headlamp according to claim 1. The optical axis of the in-vehicle headlamp according to any one of claims 1 to 4 , wherein the driving torque calculating means calculates the driving torque based on a motor torque output from a traveling motor. Control device. 6. The optical axis of an in-vehicle headlamp according to claim 5 , wherein the driving torque calculating means calculates the driving torque based on a speed ratio between the driving motor and the driving wheel and the motor torque. Control device.

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