JP2013163417A - Lighting control apparatus for vehicle headlight, and vehicle headlight system - Google Patents

Abstract

It is possible to suppress glare to a preceding vehicle at an intersection.
A lighting control device for a vehicle headlamp detects a course change of a subject vehicle based on a turn signal of the subject vehicle, and detects a course change of the subject vehicle. A steering angle determination unit 14 that determines whether or not the steering angle of the host vehicle is greater than or equal to a first threshold. When the steering angle is equal to or greater than the first threshold, the steering angle, the vehicle speed and relative A relative angle calculation unit 15 that obtains a relative angle between a front direction of the host vehicle and a target position set at a position relatively obliquely forward with respect to the front direction based on a time, and a predetermined calculation formula; The light distribution control unit 16 sets a light distribution pattern having a light shielding range corresponding to the relative angle, generates a control signal corresponding to the light distribution pattern, and outputs the control signal to the vehicle headlamp.
[Selection] Figure 1

Description

  The present invention relates to a technique for controlling an irradiation state of a vehicle headlamp.

  When driving the vehicle at night, the driver basically irradiates the road surface with a low beam with a headlamp, and confirms the front of the vehicle by irradiating a high beam as necessary. However, if light is irradiated above the so-called cut-off line, glare may be imparted to oncoming vehicles and preceding vehicles (hereinafter referred to as “front vehicles”). For this reason, in recent years, the position of the front vehicle lamp (tail lamp or headlamp) is detected using an image obtained by photographing the front vehicle with a camera mounted on the host vehicle, and the position of the front vehicle falls within the light shielding range. In this way, various techniques for controlling glare to the vehicle ahead by controlling the irradiation pattern of the high beam have been proposed (see, for example, JP 2010-238201). For example, Japanese Patent No. 4349410 also proposes a technique for suppressing glare to the vehicle ahead when entering an intersection.

  By the way, in the above-described prior example (Japanese Patent No. 4349410), a front vehicle (another vehicle) is detected by image recognition technology, and the relative displacement between the host vehicle and the front vehicle is predicted based on the detection result, and light distribution is performed. The pattern is controlled. However, in this method, for example, in the situation where the vehicle ahead is turned off and only the small lamp (vehicle width light) is turned on, it is difficult to detect the presence of the vehicle ahead by image recognition technology. There is a case where glare is given to the preceding vehicle when the course of the host vehicle is changed. In addition, a certain amount of time lag occurs after the front vehicle is detected by the image recognition technology until the light distribution pattern is actually controlled. May give. In particular, when the course of the host vehicle at the intersection is changed, the relative angular velocity between the host vehicle and the preceding vehicle increases, so that such inconvenience becomes significant.

JP 2010-238201 Japanese Patent No. 4349410

  The specific aspect which concerns on this invention makes it one of the objectives to provide the light irradiation technique which can suppress giving a glare to a preceding vehicle at the time of the course change at the intersection of the own vehicle.

  A lighting control device for a vehicle headlamp according to an aspect of the present invention is a lighting control device for controlling a light irradiation state by a vehicle headlamp, and (a) based on a winker signal of the host vehicle. A course change detection unit that detects a course change of the host vehicle; and (b) when a course change of the host vehicle is detected, it is determined whether the steering angle of the host vehicle is equal to or greater than a first threshold. A steering angle determination unit; and (c) when the steering angle of the steering wheel is equal to or greater than a first threshold, based on the steering angle of the steering wheel, the vehicle speed of the host vehicle, and the relative time, based on the front direction of the host vehicle and the front direction A relative angle calculation unit that obtains a relative angle with a target position that is set at a relatively diagonally forward position by a predetermined calculation formula, and (d) a light distribution pattern having a light shielding range corresponding to the relative angle is set. , The control signal according to the light distribution pattern Form and comprises a light distribution controller for outputting to the headlamp the vehicle.

  According to the above lighting control device, when a change in the course of the host vehicle is detected, based on the steering angle, the vehicle speed, and the relative time (relative elapsed time), the front direction of the host vehicle and the predetermined target position are determined. Since the relative angle formed is determined and the light distribution pattern is controlled using this relative angle, there is no need to use an image recognition technique. Specifically, from the time when a course change of the host vehicle is detected by a blinker signal or the like, for example, on the inner side (side closer to the host vehicle) than the target position diagonally forward in the traveling direction of the host vehicle without using image recognition technology. ) Can be set. Therefore, there is no inconvenience in using the image recognition technique as described above, and it is possible to suppress glare from being given to the preceding vehicle when the course is changed at the intersection of the own vehicle.

  In the above lighting control device, the steering angle determination unit further determines whether or not the steering wheel steering angle is equal to or smaller than a second threshold value, and the light distribution control unit determines that the steering wheel steering angle is equal to or smaller than the second threshold value. It is also preferable to stop setting the light distribution pattern using the relative angle.

  When the steering angle of the steering wheel is equal to or smaller than the second threshold value, it can be determined that the course change of the host vehicle has been completed or is close to it, and thereafter, for example, normal light distribution control using image recognition technology is performed. By switching, the light distribution control suitable for each before and after the course change can be switched smoothly.

  In the above lighting control device, the target position is set so as to correspond to the outer end of the stop line at the intersection, for example.

  In many cases, it is considered that the preceding vehicle is stopped near the stop line of the opposite lane to which the course is to be changed at the intersection, so the target position is set corresponding to the outer end (road end) of the stop line at this intersection. Thus, it is possible to set a suitable light distribution pattern in which the position of the vehicle ahead is more reliably shielded from light and the outer side is irradiated with light to increase the visibility of pedestrians and the like.

  A vehicle headlamp system according to one aspect of the present invention includes the above-described vehicle headlamp lighting control device and the vehicle headlamp controlled by the lighting control device.

  This provides a vehicle headlamp system that can suppress glare on the preceding vehicle when the route is changed at the intersection of the host vehicle.

FIG. 1 is a block diagram illustrating a configuration of a vehicle headlamp system according to an embodiment. FIG. 2 is an exploded perspective view illustrating a configuration example of the optical unit. FIG. 3A and FIG. 3B are diagrams schematically showing the state of light distribution control at the intersection of the vehicle headlamp system. FIG. 4 is a diagram showing the positional relationship between the front wheels and the rear wheels of the host vehicle. FIG. 5 is a model diagram showing a change in position when the route is changed at the intersection of the subject vehicle. FIG. 6 is a flowchart showing an operation procedure of the vehicle headlamp system. FIG. 7 is a diagram for explaining the contents of the conditions corresponding to the left turn / right turn. FIG. 8 is a diagram for explaining an example of setting conditions. FIG. 9A shows an example of detecting the actual vehicle speed, FIG. 9B shows an example of detecting the actual steering angle, and FIG. 9C shows the actual relative angle (the target position and the front of the host vehicle). It is a figure which shows the example of calculation of the angle formed with a direction.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 is a block diagram illustrating a configuration of a vehicle headlamp system according to an embodiment. The vehicle headlamp system shown in FIG. 1 performs light irradiation by setting a light distribution pattern based on an image obtained by imaging a space (target space) in front of the host vehicle with a camera 10. A central control unit 11 and two optical units 20R and 20L connected to the central control unit 11 are provided.

  The camera 10 is installed at a predetermined position (for example, in the vicinity of an indoor mirror) of the host vehicle and captures a space in front of the host vehicle.

  The central control unit 11 includes a vehicle detection unit 12, a course change detection unit 13, a steering angle determination unit 14, a relative angle calculation unit 15, and a light distribution control unit 16. The central control unit 11 is realized by executing a predetermined operation program in a computer system having, for example, a CPU, a ROM, a RAM, and the like.

  The vehicle detection unit 12 obtains an image (image data) obtained by photographing the space ahead of the host vehicle from the camera 10 and performs image recognition processing on the image, whereby the vehicle ahead (target vehicle). The position information of is detected.

  The course change detection unit 13 detects a course change of the host vehicle based on the winker signal of the host vehicle. The course change here means a left turn or a right turn while operating the winker, and does not include a turner that does not involve the operation of the winker.

  The steering angle determination unit 14 determines whether or not the steering angle of the host vehicle is greater than or equal to a predetermined value (first threshold) when the course change detection unit 13 detects the course change of the host vehicle, and steering the steering. It is determined whether or not the corner is equal to or smaller than a predetermined value (second threshold).

  When the steering angle is equal to or larger than the first threshold and equal to or smaller than the second threshold, the relative angle calculation unit 15 is based on the steering angle, the vehicle speed of the host vehicle, and the relative elapsed time (relative time). A relative angle between the front direction of the host vehicle and the target position set at a position relatively obliquely forward with respect to the front direction is obtained by a predetermined calculation formula.

  The light distribution control unit 16 sets a light distribution pattern having a light shielding range corresponding to the position information of the preceding vehicle obtained by the vehicle detection unit 13 or a light shielding range corresponding to the relative angle calculated by the relative angle calculation unit 15. A control signal (light distribution control signal) is output to each of the optical units 20R and 20L so that light is emitted according to the set light distribution pattern.

  The optical unit 20R is installed on the front right side of the host vehicle and used to irradiate light that illuminates the front of the host vehicle. Similarly, the optical unit 20L is installed on the front left side of the host vehicle, and is used for irradiating light that illuminates the front of the host vehicle. As shown in the drawing, the optical units 20R and 20L have a common configuration. Specifically, each of the optical units 20R and 20L includes a unit-side control unit 21, an LED lighting circuit 22, and seven LEDs (light emitting devices) connected in parallel to each other. Element) 1-7.

  The unit-side control unit 21 receives a control signal (LED lighting / lighting signal) from the light distribution control unit 16 and gives a control signal to the LED lighting circuit 22 to turn on / off the LEDs 1 to 7 and the intensity of each LED. Are controlled individually.

  The LED lighting circuit 22 controls turning on and off of the LEDs 1 to 7 by individually supplying drive signals (drive currents) to the LEDs 1 to 7 based on the control signal from the light distribution control unit 16 and driving. Each luminous intensity is controlled by the magnitude of the current.

  FIG. 2 is an exploded perspective view illustrating a configuration example of the optical unit. As shown in FIG. 2, the optical unit 20R (or 20L) is disposed behind the projection lens 41 disposed on the optical axis AX extending in the vehicle front-rear direction and the rear focal plane of the projection lens 41. The light source unit 30, a lens holding frame 40 that holds the projection lens 41 in a predetermined position, and a heat sink 50 attached to the light source unit 30 are configured. The optical unit 20R is integrated by attaching the projection lens 41 to the lens holding frame 40 and fixing the lens holding frame 40 to the heat sink 50 with screws. The light source unit 30 includes an interference prevention member 32 formed by integrating a plurality of light guide lens portions 31 and a plurality of LEDs arranged in one direction (horizontal direction) and is disposed behind the interference prevention member 32. The light emitting element substrate 33 is included. The LEDs provided on the light emitting element substrate 33 are the LEDs 1 to 7 connected to the LED lighting circuit 22 described above. The light emitted from each LED is guided to the projection lens 41 by each light guide lens portion 31 of the interference preventing member 32 and projected in front of the host vehicle. At this time, by individually controlling lighting / extinguishing of each light emitting element, it is possible to freely control the light distribution pattern such as partially shielding the high beam irradiation area. By making the light distribution area where the preceding vehicle and the oncoming vehicle are present non-illuminated and other light distribution areas illuminated, the dazzling of the preceding vehicle, etc. is prevented and the visibility of the driver of the host vehicle is increased. be able to.

  Hereinafter, the operation of the vehicle headlamp system of the present embodiment will be described in detail. First, the principle of the light distribution control of the vehicle headlamp system according to the present embodiment based on the winker signal, the steering angle, and the vehicle speed of the host vehicle at the intersection will be described in detail.

  FIG. 3A and FIG. 3B are diagrams schematically showing the state of light distribution control at the intersection of the vehicle headlamp system. As shown in FIG. 3A, consider a case where the host vehicle enters an intersection while irradiating a high beam and changes the course (here, a left turn). At this time, if the high beam is irradiated, glare will be given to the forward vehicle existing ahead of the left turn. In order to avoid this, the vehicle headlamp system has a light-shielding range in the area where the front vehicle may exist when the vehicle changes its course at the intersection as shown in FIG. Light distribution control is performed so that other areas (such as road edges) are outside the light shielding range. Thereby, the visibility of a pedestrian or the like at the end of the road is improved while preventing glare from being given to the preceding vehicle. The vehicle headlamp system according to the present embodiment realizes the light distribution control as described above according to the principle described below without detecting the vehicle ahead by image recognition processing.

FIG. 4 is a diagram showing the positional relationship between the front wheels and the rear wheels of the host vehicle. Here, for simplification, only one front wheel and one rear wheel are considered. As shown, the axle pitch between front and rear wheels of the vehicle (the mutual distance) L, the radius of curvature Rt, the minimum turning radius R _min, a front wheel turning angle theta _T, the maximum value of theta _T theta _{T (max),} the steering angle theta _ST, the maximum value of theta _ST and θ _{ST (max).}
At this time, the front wheel turning angle θ _T can be expressed by the following equation.
Here, the relationship between the steering angle θ _ST and the front wheel turning angle θ _T is assumed by the following equation.
Thereby, the relationship between the steering angle θ _{ST_t} and the curve radius Rt at a certain time t can be obtained by the following equation.
As an example, assuming that the minimum turning radius R _min of the host vehicle is 5.8 m, the inter-axle pitch L is 2.8 m, and the maximum steering angle θ _{ST (max)} is 558 deg, the maximum steering angle θ _{T (Max)} is expressed as follows.
From the above, the relationship between the steering angle θ _{ST_t} and the curve radius Rt at a certain time t can be obtained by the following equation.
By preparing such a relational expression in advance corresponding to various conditions of the host vehicle, the curve radius can be obtained from the steering angle of the host vehicle.

FIG. 5 is a model diagram showing a change in position when the route is changed at the intersection of the subject vehicle. In FIG. 5, the time when the turn signal of the host vehicle indicates a “left turn” state (P _turn-on ) and the steering wheel steering angle θ _ST exceeds a certain value is defined as time t = 0. The coordinate value is P ₀ (0, 0). Further, the front direction of the host vehicle when t = 0 is defined as the Y axis, and the direction orthogonal thereto is defined as the X axis.
At this time, the inclination angle θ _{tilt_t} of the _host vehicle from the Y axis at time t is _{expressed as} follows, where the vehicle speed of the _host vehicle is v _t and the relative time is (t _t −t _t−1 ).
At this time, the position P _t (x _t , y _t ) of the host vehicle at time t is expressed as follows.
In addition, a target position that defines a vertical cut-off line when setting a light shielding range in the light distribution pattern of the host vehicle is defined as P _target (x _target , y _target ). This target position P _target is set corresponding to the outer end of the stop line at the intersection as shown in the figure, for example. Actually, the target position P _target is determined as a relative positional relationship based on, for example, the position P ₀ of the host vehicle at the time t = 0.
From the above, the relative angle θ _{target —} t between the front direction of the _host vehicle at time t and the direction in which the _host vehicle and the target position P _target exist can be _obtained by the following equation.
Therefore, by using this angle θ _{target — t} as the control angle, it is possible to set the light distribution pattern so that at least the inside of the target position P _target is a light shielding range and the outside is outside the light shielding range. In the present embodiment, the above light distribution control is executed until the steering angle of the steering wheel falls below a certain value (the position of the host vehicle: P _end ).

  Next, an example of the operation procedure of the vehicle headlamp system according to the present embodiment based on the above principle will be described. FIG. 6 is a flowchart showing an operation procedure of the vehicle headlamp system.

  The course change detection unit 13 detects a blinker signal from the host vehicle (step S11), and determines whether or not the blinker signal is output (step S12). When the winker signal is output (step S12; YES), the course change detection unit 13 determines whether the winker signal indicates a right turn or a left turn (step S13).

  When the winker signal indicates a left turn, the course change detection unit 13 sets a condition for a left turn used in later processing (step S14). Similarly, when the winker signal indicates a right turn, the course change detection unit 13 sets a right turn condition used in later processing (step S15).

FIG. 7 is a diagram for explaining the contents of the conditions corresponding to the left turn / right turn. As shown in the figure, two conditions are set as a “handle steering angle threshold value” that is a reference value related to the steering angle of the host vehicle and a “target position” used when setting a light shielding range. Regarding the steering wheel steering angle threshold value, a threshold value “ON _L ” for determining switching from the normal control at the left turn to the intersection control and a threshold value “OFF _L ” for determining the reverse switching, and the normal control at the right turn There is a threshold value “ON _R ” for determining the switching from to the intersection control and a threshold value “OFF _R ” for determining the reverse switching. Regarding the target position, there are an x-direction coordinate value X _L and a y-direction coordinate value Y _L when turning left, and an x-direction coordinate value X _R and a y-direction coordinate value Y _R when turning right. FIG. 8 is a diagram for explaining an example of setting conditions. As shown in the figure, for example, the threshold values ON _L , OFF _L , ON _R , and OFF _R may all be set to the same value (set value 1), or may be set to different values (set value 2). Each threshold value ON _L = ON _R and OFF _L = OFF _R may be set (set value 3). For each coordinate value, X _L ≠ X _R and Y _L ≠ Y _R may be set (set value 4), or X _L ≠ X _R and Y _L = Y _R may be set (set value 5).

Next, the steering angle determination unit 14 detects a steering wheel steering angle signal based on the steering angle signal from the host vehicle (step S16), and the steering wheel steering angle of the host vehicle is set to the predetermined value set in step S14 or step S15. It is determined whether or not the steering wheel steering angle threshold value (ON _L or ON _R ) that is a value is greater than or equal to (step S17).

  When the steering wheel steering angle is equal to or larger than the predetermined value (step S17; YES), the relative angle calculation unit 15 detects the steering wheel steering angle and the vehicle speed based on the steering angle signal and the vehicle speed signal (step S18). Further, the relative angle calculation unit 15 calculates the relative time (step S19). The relative time may be calculated using, for example, a vehicle speed signal, or may be calculated by creating a timer.

Next, the relative angle calculation unit 15 uses the detected steering angle of the steering wheel and the vehicle speed and the calculated relative time, and based on the above relational expression, the relative angle θ between the front direction of the host vehicle and a preset target position. _{target_t} is calculated (step S20).

When the relative angle θ _{target_t} is calculated, the light distribution control unit 16 sends a light distribution control signal for realizing a light distribution pattern having a light shielding range based on the relative angle θ _{target_t} to each of the optical units 20R and 20L. Output (step S21).

Next, the steering angle determination unit 14 detects the steering angle of the steering wheel based on the steering angle signal from the own vehicle, and the steering wheel steering angle of the own vehicle is the predetermined value set in step S14 or step S15. It is determined whether or not it is equal to or less than the angular threshold (OFF _L or OFF _R ) (step S22). If the steering angle is not less than the predetermined value (step S22; NO), the process returns to step S18 and the subsequent processing is executed. If the steering angle is equal to or smaller than the predetermined value (step S22; YES), the series of processes is terminated, and thereafter the processes after step S11 are executed at an appropriate timing.

  It should be noted that when the winker signal does not exist in step S12 (step S12; NO), or when the steering wheel steering angle is not greater than or equal to a predetermined value in step S17 (step S17; NO), the own vehicle Therefore, the normal light distribution control is executed. That is, the vehicle detection unit 12 detects the position information of the front vehicle using an image ahead of the host vehicle (step S23). Then, based on the detected position information of the preceding vehicle, the light distribution control unit 16 outputs a light distribution control signal for realizing a light distribution pattern having a light-shielding range corresponding to the area where the preceding vehicle exists for each optical signal. Output to each of the units 20R and 20L (step S24).

FIG. 9A shows an example of detecting the actual vehicle speed, FIG. 9B shows an example of detecting the actual steering angle, and FIG. 9C shows the actual relative angle (the target position and the front of the host vehicle). It is a figure which shows the example of calculation of the angle formed with a direction. In addition, the experimental result at the time of making a left turn of the own vehicle at the intersection is shown here. As shown in FIG. 9B, the steering wheel steering angle threshold values ON _L and OFF _L are both set to “−50 deg”, and within a period determined by this threshold value after the blinker signal is detected (here Then, the light distribution control at the intersection is executed in a time period of about 6 seconds to 10 seconds. Then, as shown in FIG. 9C, the relative angle is calculated continuously between approximately −25 deg and 110 deg within this period. An appropriate light distribution pattern is realized by setting the light shielding range using such a relative angle.

  According to the present embodiment as described above, the front direction of the host vehicle and the predetermined target position are determined based on the steering angle, the vehicle speed, and the relative time (relative elapsed time) when the course change of the host vehicle is detected. Since the light distribution pattern is controlled using this relative angle, the image recognition technique does not need to be used in principle. Specifically, from the time when a course change of the host vehicle is detected by a blinker signal or the like, for example, on the inner side (side closer to the host vehicle) than the target position diagonally forward in the traveling direction of the host vehicle without using image recognition technology. ) Can be set. Therefore, there is no inconvenience in using the image recognition technique as described above, and it is possible to suppress glare from being given to the preceding vehicle when the course is changed at the intersection of the own vehicle.

  In addition, this invention is not limited to the content of embodiment mentioned above, In the range of the summary of this invention, it can change and implement variously. For example, the control of the light distribution pattern has been described with an example in which the LEDs are turned on and off, but a light source such as an LED may be turned on, and an area to be turned off may be shielded by a light shielding unit.

1-7: LED
DESCRIPTION OF SYMBOLS 10: Camera 11: Central control part 12: Vehicle detection part 13: Course change detection part 14: Steering angle determination part 15: Relative angle calculation part 16: Light distribution control part 20R, 20L: Optical unit 21: Unit side control part 22 : LED lighting circuit

Claims (4)

A lighting control device for controlling a light irradiation state by a vehicle headlamp,
A course change detection unit that detects a course change of the host vehicle based on a winker signal of the host vehicle;
A steering angle determination unit that determines whether or not a steering wheel steering angle of the host vehicle is equal to or greater than a first threshold when a change in the course of the host vehicle is detected;
When the steering wheel steering angle is equal to or greater than the first threshold, the front direction of the host vehicle and the front direction of the host vehicle are relatively inclined based on the steering wheel steering angle, the vehicle speed and the relative time of the host vehicle. A relative angle calculation unit for obtaining a relative angle with a target position set at a position that is in front by a predetermined calculation formula;
A light distribution control unit that sets a light distribution pattern having a light shielding range according to the relative angle, generates a control signal according to the light distribution pattern, and outputs the control signal to the vehicle headlamp;
A lighting control device for a vehicle headlamp. The steering angle determination unit further determines whether or not the steering angle of the steering wheel is equal to or less than a second threshold;
2. The vehicle front according to claim 1, wherein the light distribution control unit stops setting the light distribution pattern using the relative angle when the steering wheel steering angle is equal to or less than the second threshold. Lighting control device for lighting.   The lighting control device for a vehicle headlamp according to claim 1 or 2, wherein the target position is set so as to correspond to an outer end of a stop line at an intersection. A lighting control device for a vehicle headlamp according to any one of claims 1 to 3,
A vehicle headlamp controlled by the lighting control device,
Including a vehicle headlamp system.