(12) United States Patent
`Nishimura
`
`(10) Patent N0.:
`(45) Date of Patent:
`
`US 6,547,425 B2
`Apr. 15, 2003
`
`US006547425B2
`
`(54) AUTOMATIC HEADLIGHT AIMING DEVICE
`FOR VEHICLES
`
`(56)
`
`References Cited
`U.S. PATENT DOCUMENTS
`
`(75) Inventor: Kenichi Nishimura, Gifu (JP)
`
`(73) Assignee; Denso Corporation, Kariya (JP)
`
`6,130,506 A * 10/2000 Lopez 6161. ................ .. 315/82
`6,176,590 B1 * 1/2001 PreVOst et a1. ..
`..... .. 362/37
`6,343,869 B1 * 2/2002 Kobayashi ................. .. 362/37
`
`FOREIGN PATENT DOCUMENTS
`
`7/2000
`6/1998
`2/1995
`53/1995
`9/1995
`
`19860676
`DE
`0847895 A2
`EP
`07047878
`JP
`A-7-32936
`JP
`07246873
`JP
`* cited by examiner
`Primary Examiner—Sandra O’Shea
`Assistant Examiner—Sharon Payne
`(74) Attorney, Agent, or Firm—Nixon & Vanderhye PC.
`(57)
`ABSTRACT
`
`The present invention changes the headlight optical axis of
`a vehicle in relation to an inclination angle during normal
`control and to properly adjust the optical axis according to
`information including front information about a car ahead.
`The headlight optical axis is adjusted based on the inclina
`tion angle of a vehicle, road information in the direction of
`travel, presence of a car ahead, a distance betWeen vehicles,
`and the center optical axis angle corrected according to
`changes in horizontal and vertical behavior of the car ahead.
`
`13 Claims, 5 Drawing Sheets
`
`( * ) Notice:
`
`_
`
`_
`
`_
`
`_
`
`_
`
`SubJect to any disclaimer, the term of this
`patent is extended or adjusted under 35
`U.S.C. 154(b) by 0 days.
`
`(21) APPI- NO-I 09/824,536
`(22) Filed:
`Apr. 3, 2001
`(65)
`Prior Publication Data
`
`US 2001/0039469 A1 Nov. 8, 2001
`Foreign Application Priority Data
`
`(30)
`
`Apr. 3, 2000
`Mar. 14,2001
`
`(JP) ..................................... .. 2000-100561
`(JP) ..................................... .. 2001-071408
`
`(51) Int. Cl.7 .......................... .. B60Q 1/06; B60Q 1/08;
`B60Q 1/10; F21V 1/00
`(52) US. Cl. ....................... .. 362/466; 362/467; 362/37;
`362/276
`(58) Field of Search ............................... .. 362/464, 465,
`362/466, 467, 37, 459, 276, 802; 340/465,
`466, 467; 315/76, 77, 78, 79, 80, 81, 82,
`83, 84
`
`CAR AHEAD
`
`OPTICAL AXIS
`CENTER ANGLE
`
`Page 1 of 12
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`BMW 1019
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`

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`U.S. Patent
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`Apr. 15,2003
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`Sheet 1 of5
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`US 6,547,425 B2
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`Page 2 of 12
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`

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`U.S. Patent
`
`Apr. 15,2003
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`Sheet 2 of5
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`US 6,547,425 B2
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`(
`
`START
`
`)
`
`F|G.3
`
`VEHICLE INFORMATION M8101
`DETECTION PROCESS
`L
`FRONT INFORMATION
`DETECTION PROCESS
`
`3102
`
`S103
`Axe HORIZONTAL
`EAD ZONE?
`
`S105
`[J
`
`TARGET ANGLE OF
`HORIZONTAL OPTICAL AXIS
`A6x=tan-1 (Ax/d)
`
`TARGET ANGLE OF
`HORIZONTAL OPTICAL AXIS M8104
`A 6x<—0
`
`A 9x FILTERING
`
`M8106
`
`S109
`
`TARGET ANGLE OF
`VERTICAL OPTICAL AXIS
`A 8yztan‘1 (Ay/d)
`
`TARGET ANGLE OF
`VERTICAL OPTICAL AXIS
`A 9y<—0
`
`'\/S108
`
`A ey FILTERING
`I
`OPTICAL AXIS CONTROL M8111
`
`TVSHO
`
`(
`
`RETURN
`
`)
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`Page 3 of 12
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`

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`U.S. Patent
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`Apr. 15,2003
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`Sheet 3 of5
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`US 6,547,425 B2
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`IL
`
`RO~
`
`DISTANCE BETWEEN CARS
`
`FIG. 5
`
`W/Z
`
`Tl
`
`/
`
`LEFT TURN HORIZONTAL RIGH
`T TURN
`RANGE
`‘DEAD ZONE
`RANG
`E
`
`Page 4 of 12
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`

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`U.S. Patent
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`Apr. 15,2003
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`Sheet 4 of5
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`US 6,547,425 B2
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`OPTICAL AXIS
`CENTER ANGLE
`
`FIG. 8
`
`FIG. 9
`
`Page 5 of 12
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`

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`U.S. Patent
`
`Apr. 15,2003
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`Sheet 5 of5
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`US 6,547,425 B2
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`FIG. 10
`
`FIG. 11
`
`SUPPLEMENTAL
`PROJECTION
`
`Page 6 of 12
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`US 6,547,425 B2
`
`1
`AUTOMATIC HEADLIGHT AIMING DEVICE
`FOR VEHICLES
`
`CROSS-REFERENCE TO RELATED
`APPLICATION
`
`The present invention is related to Japanese patent appli
`cation No. 2001-71408, ?led Mar. 14, 2001, the contents of
`Which are incorporated herein by reference.
`
`FIELD OF THE INVENTION
`
`The present invention relates to an automatic headlight
`aiming device, and more particularly to an automatic head
`light aiming device that automatically adjusts the direction
`of the vehicle headlights optical axis.
`
`BACKGROUND OF THE INVENTION
`In conventional vehicle headlights, oncoming vehicle
`drivers are blinded if the direction of the headlight optical
`axis is directed upWard by the vehicle body inclination.
`Alternatively, if directed doWnWard, the driver’s distance
`visibility is reduced. Therefore, there is a demand for
`keeping the headlight optical axis ?xed.
`There is also conventional headlight adjusting device
`capable of controlling the range of light projection of the
`headlights according to information from a car navigation
`system mounted in the vehicle. This type of control device
`controls the headlight optical axis direction according to
`map information given by the car navigation system.
`HoWever, it is difficult to control the headlight optical axis
`direction corresponding to actual road conditions because of
`various errors.
`There is also a conventional system Which recogniZes a
`reference point on the car ahead after image processing by
`a CCD camera estimates conditions of the car ahead. Such
`a system is disclosed in JP-A-7-32936. It then controls a
`headlight optical axis based on the detected road conditions.
`HoWever, this system uses the largest point of illumina
`tion on the car ahead to decide the reference point. As such,
`sometimes this camera catches a bright street light or other
`illuminated object instead of the vehicle. Moreover, this
`system is only useful at night.
`
`SUMMARY OF THE INVENTION
`The present invention provides an automatic headlight
`aiming device that adjusts the vehicle’s driving environment
`according to information including cars ahead, While alloW
`ing deviation from a control angle in ordinary control for
`holding the optical axis of the headlights in a ?xed direction.
`In one aspect of the invention, the inclination angle of the
`headlight optical axis from the road surface is computed by
`the inclination angle computing means by referencing the
`vehicle information detecting means Which detects the incli
`nation information of a vehicle, movement information, and
`acceleration information. Then, the headlight optical axis is
`adjusted by the optical axis adjusting means, With reference
`to the optical axis center angle determined by correcting and
`computing the inclination angle by the optical axis center
`angle computing means according to the front information
`fed from the front information detecting means. That is, road
`information in the direction of vehicle travel is detected by
`the vehicle information detecting means. The presence or
`absence of a car ahead, distance betWeen vehicles, and
`upWard and doWnWard behavior variations are detected by
`the front information detecting means. Therefore, beside a
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`2
`normal control by the inclination angle obtained from the
`vehicle information, the adjustment of the optical axis is
`performed, When needed, by referring to road information
`and the optical axis center angle after correction by a
`behavior change of a car ahead. It is therefore possible to
`improve the driver’s visibility of a forWard road condition
`and a car ahead When changing to correct the normal control
`of the headlight optical axis direction Without blinding the
`driver in the car ahead.
`In another aspect, the center angle of the optical axis is
`computed by the optical axis center angle computing means
`after correction by using the horiZontal and vertical displace
`ment of the car ahead. When a speci?c threshold value is
`exceeded, the inclination angle is corrected to compute the
`center optical axis angle. Thus, the headlight optical axis
`direction is properly corrected Without causing the driver to
`feel uncomfortable.
`In another aspect, When the horiZontal displacement of the
`car ahead exceeds a predetermined value, the range of light
`projection is changed according to the vehicle’s turning
`direction by the horiZontal adjusting means. The horiZontal
`adjusting means adjusts the headlight optical axis in the
`horiZontal direction.
`In another aspect, When the displacement exceeding the
`predetermined value is detected by a horiZontal change of
`the car ahead, the right front or left front supplementary
`lamp of the vehicle is lit to Widen the range of light
`projection.
`Further areas of applicability of the present invention Will
`become apparent from the detailed description provided
`hereinafter. It should be understood that the detailed descrip
`tion and speci?c examples, While indicating preferred
`embodiments of the invention, are intended for purposes of
`illustration only, since various changes and modi?cations
`Within the spirit and scope of the invention Will become
`apparent to those skilled in the art from this detailed descrip
`tion.
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`The present invention Will become more fully understood
`from the detailed description and the accompanying
`draWings, Wherein:
`FIG. 1 is a schematic vieW of an automatic headlight
`adjusting device according to the invention;
`FIG. 2 is a cross-sectional vieW of a headlight according
`to the invention;
`FIG. 3 is a ?oWchart of a control routine for controlling
`the headlight optical axis direction according to the inven
`tion;
`FIG. 4 is a schematic vieW shoWing the computation of
`the headlight optical axis inclination angle With reference to
`a distance from a car ahead according to the invention;
`FIG. 5 is a schematic vieW shoWing a reference point of
`the car ahead being tracked by a laser radar mechanism
`according to the present invention;
`FIG. 6 is a table shoWing horiZontal and vertical dead
`Zones and surrounding ranges in relation to displacement
`from the reference point Within a predetermined time
`according to the invention;
`FIG. 7 is a schematic vieW shoWing the headlight optical
`axis tracking the behavior of the car ahead on an uphill by
`the automatic headlight aiming device for vehicles accord
`ing to the invention;
`FIG. 8 is a schematic vieW shoWing the control of the
`headlight optical axis direction tracking the behavior of the
`car ahead doWnhill according to the invention;
`
`Page 7 of 12
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`

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`US 6,547,425 B2
`
`3
`FIG. 9 is a schematic vieW showing the control of the
`headlight optical axis direction tracking the behavior of the
`car ahead according to the invention;
`FIG. 10 is a schematic vieW shoWing tracking of the
`right-turn of the car ahead according to the invention; and
`FIG. 11 is a schematic vieW shoWing headlight optical
`aXis control tracking the right-turn of the car ahead accord
`ing to the invention.
`DETAILED DESCRIPTION OF THE
`INVENTION
`In FIG. 1, a height sensor 11 is mounted on the rear Wheel
`axle, either on the driver’s or passenger’s seat side of the
`vehicle. From the height sensor 11, the relative displacement
`betWeen the rear Wheel aXle and the vehicle body, that is, the
`rear vehicle height (the displacement of the vehicle height
`on the rear Wheel side), and signals from other sensors such
`as a vehicle speed sensor (not shoWn) and a G sensor (not
`shoWn) are input to an ECU (electronic control unit) 20
`mounted on the vehicle.
`The ECU 20 is a logical operation circuit comprising a
`CPU 21, a ROM 22 storing a control program, a RAM 23
`storing various kinds of data, a B/U (backup) RAM 24, an
`I/O (input/output) circuit 25, and a bus line 26 for connect
`ing these parts. An output signal from the ECU 20 is input
`to actuators 35 and 36 located on the headlight 30 side,
`thereby adjusting the headlight optical aXis direction 30.
`The vehicle is provided With a knoWn laser radar mecha
`nism 40, for instance in the front bumper section, for
`detecting information in front of the vehicle. This
`information, such as a distance from and a change in
`behavior in the car ahead, thus detected by the laser radar
`mechanism 40 are input into the ECU 20 as described later.
`This information is used to adjust the direction of headlight
`optical aXis 30. Also mounted on the vehicle is a knoWn car
`navigation system (not shoWn) for detecting road informa
`tion. It is understood that an image information processing
`system using an EHF radar mechanism and a CCD camera
`may be similarly mounted in place of the laser radar mecha
`nism 40 for detecting the information in front of a vehicle.
`In FIG. 2, the headlight 30 is comprised chie?y of a lamp
`31, a re?ector 32 securing the lamp 31, a support section 33
`Which supports the re?ector 32 and sWings in the direction
`of the arroWs, another movable part 34 Which supports
`re?ector 32, the actuator 35 such as a step motor for driving
`the movable part 34 back and forth in the directions of the
`arroWs, and an actuator 36 including a step motor for driving
`an integrated assembly of these components rotationally for
`horiZontal adjustment as indicated by the arroW. The initial
`setting of the headlight 30 optical aXis is performed based on
`that only the driver is in the vehicle.
`NeXt, FIG. 3 is a ?oWchart shoWing an optical aXis
`adjustment control routine for adjusting the headlight optical
`aXis direction 30 With the CPU 21 of the ECU 20. Referring
`to FIGS. 4, 5 and 6. The control routine is repetitively
`eXecuted by the CPU 21 at a predetermined time.
`It is ?rst brie?y described hoW the position of the refer
`ence point S is determined. It is knoWn that a laser radar
`mechanism calculates the distance betWeen the present
`vehicle and the car ahead, and then calculates relative speed.
`Further, When the object is recogniZed as the car driving
`Within the predetermined area based on the relative speed,
`the car is folloWed. Moreover, it is knoWn that the position
`is calculated on an XYZ coordinate aXis based on the bounce
`of the laser Which is re?ected by the speci?c position of the
`car ahead. Therefore, the reference point S is calculated as
`shoWn below.
`
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`35
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`45
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`65
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`4
`At step S101 in the ?oWchart of FIG. 3, the vehicle
`information detection process, for instance the inclination
`angle, is eXecuted With reference to the value of rear vehicle
`height supplied from the height sensor 11. Also detected for
`vehicle inclination attitude includes movement, acceleration
`and deceleration of the vehicle from the car navigation
`system, speed from the speed sensor, force from the G
`sensor, etc. Subsequently, at step S102, as shoWn in FIG. 4,
`the distance d betWeen vehicles is detected and the inclina
`tion angle 0 of the headlight optical aXis 30 is given by the
`equation beloW (1) to detect information in front of the
`vehicle by the laser radar mechanism 40. In the equation, h1
`is a vehicle height above the road surface at Which the driver
`of the car ahead Will not be blinded, for eXample, a height
`to the center point (W/2) of a re?ector in either stoplight as
`the reference point S in the car ahead as shoWn in FIG. 5.
`Furthermore, the height h2 is a height from the road surface
`up to the center position of the headlight 30 optical aXis of
`the vehicle. For the heights h1 and h2, preset constants may
`be used. The height h1 may be changed according to the
`detected height of the car ahead. The height h2 may be a
`computed value based on the vehicle height, vehicle
`inclination, and a distance from the headlights 30 and the
`Wheel aXle.
`Equation 1
`
`Furthermore, at step S102, the amount of horiZontal
`displacement AX as the amount of horiZontal
`displace
`ment Within a predetermined time of the reference point S of
`the car ahead, and the amount of vertical displacement Ay as
`the amount of vertical (V) displacement Within a predeter
`mined time at the reference point S are detected as shoWn in
`FIG. 6.
`NeXt, at step S103, it is evaluated Whether the amount of
`H displacement AX of the reference point S detected at step
`S102 is in the horiZontal dead Zone. The horiZontal dead
`Zone is provided for a dull reaction to slight horiZontal
`variations of the reference point S of the car ahead. Where
`the amount of horiZontal displacement AX at step s103 is
`Within the horiZontal dead Zone, the displacement Within the
`predetermined time is small. At step S104, the target hori
`Zontal optical aXis AGX is set at 0°. In the meantime, Where
`in step S103, the horiZontal displacement AX is largely in the
`left-turn right-turn range, out of the horiZontal dead Zone, a
`large displacement is Within a predetermined period of time.
`Then, in step 105, the target horiZontal optical aXis AGX is
`given by the folloWing equation
`Equation 2
`
`Subsequent to step S104 or S105, the process goes to step
`106, Where the target horiZontal optical aXis AGX is ?ltered.
`That is, the target angle of the horiZontal optical aXis AGX is
`smoothed so that the headlight optical aXis 30 Will not be
`suddenly horiZontally changed, not making the driver
`uncomfortable. NeXt, at step S107, Whether the vertical
`displacement Ay of reference point S detected at step S102
`is involved in the vertical dead Zone is determined. The
`vertical dead Zone is provided for a dull reaction to slight
`vertical variations of the reference point S caused by accel
`eration and deceleration of the car ahead. When the vertical
`displacement Ay S107 is Within the vertical dead Zone, the
`process goes to step S108 because the displacement Within
`the predetermined time is small. At step S108 the target
`angle of vertical optical aXis A?y is set at 0°. On the other
`
`Page 8 of 12
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`US 6,547,425 B2
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`5
`hand, When step S108 is not determined, that is, When the
`vertical displacement Ay is largely into the upper or loWer
`optical axis range, out of the vertical dead Zone, the process
`goes to step S109, Where the target angle of vertical optical
`axis AGy is given by the folloWing equation
`Equation 3
`
`After step S108 or S109, the process goes to step S110,
`Where the target angle of vertical optical axis AGy is ?ltered.
`That is, the target angle of vertical optical axis AGy is
`smoothed so that the headlight optical axis 30 Will not be
`suddenly vertically changed, thereby not causing discomfort
`to the driver and others. Next, at step S111, the actuators 35
`and 36 are driven With reference to the inclination angle
`during normal control to hold the headlight 30 optical axis
`in a ?xed direction (doWnWard 1% [or 1.2%]) to ensure a
`driver’s has road visibility Without blinding oncoming driv
`ers. The center optical axis angle is corrected by adding, to
`the inclination angle, the target horiZontal optical axis AGx
`?ltered at step S106 and the target angle of vertical optical
`axis AGy ?ltered at step S110, thus completing the control
`routine.
`The horiZontal dead Zone Width and the vertical dead Zone
`shoWn in FIG. 6 may be ?xed, or may be changed by the
`distance betWeen vehicles or by vehicle speed. It may be set
`such that the farther the car ahead is forWard, the narroWer
`the horiZontal dead Zone and the vertical dead Zone. Also,
`the horiZontal dead Zone can be narroW symmetrically in the
`horiZontal direction, or asymmetrically in the right direction,
`to thereby ensure easy reaction to behavior changes of the
`car ahead. Furthermore the vertical dead Zone also may be
`narroWed symmetrically in the vertical direction or asym
`metrically on the doWnWard direction, thereby enabling easy
`reaction to changes ahead.
`An example is explained With respect to FIGS. 7 to 10. As
`shoWn in FIG. 7, When a car ahead moving straightforWard
`has begun going up a hill, a change in the reference point S
`on the car ahead is detected by the laser radar mechanism 40.
`When the displacement detected With the change in the
`upWard behavior of the car ahead goes out of the vertical
`dead Zone and into the upper range of optical axis (see FIG.
`6), the target angle of the vertical optical axis AGy is
`computed by the equation
`Using the target angle of the
`vertical optical axis AGy thus computed, the headlight opti
`cal axis direction 30 is corrected upWard. This correction is
`performed at predetermined time intervals.
`FIG. 8 is an explanatory vieW shoWing the correction of
`the headlight 30 optical axis of a vehicle tracking the car
`ahead on a doWnhill. As shoWn in FIG. 8, When the car ahead
`has gone doWnhill to a level road, a change in the upWard
`behavior of the reference point S is detected by the laser
`radar mechanism 40. If the displacement detected With
`change in upWard movement of the car ahead moves out of
`the vertical dead Zone and into the upper range of optical
`axis (see FIG. 6), the target angle of vertical optical axis AGy
`is computed by the equation
`The optical axis direction
`of the headlight 30 is corrected upWard according to the
`target angle of vertical optical axis AGy thus computed.
`Since this correction is conducted every predetermined time
`increment according to a behavior change of the car ahead,
`the direction of the headlight 30 optical axis can be matched
`With a behavior change in the car running ahead.
`FIG. 9 is an explanatory vieW shoWing the correction
`control of the headlight optical axis 30 tracking the behavior
`of the car running ahead near a hilltop. As shoWn in FIG. 9,
`When the car running straightforWard ahead is going down
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`hill and the other car is going uphill, a doWnWard change of
`reference point S is detected. When this displacement leaves
`the vertical dead Zone and goes into the loWer range of
`optical axis (see FIG. 6), the target angle of vertical optical
`axis Aey is computed by the equation (3), thereby correcting
`the headlight 30 optical axis doWnWard. Since correction
`control is carried out at predetermined times according to a
`behavior change of the car ahead, the headlight optical axis
`30 can be matched With the change in behavior of the car
`ahead.
`FIG. 10 is an explanatory vieW shoWing the correction
`control of the headlight 30 optical axis tracking the right
`turn behavior of the car running ahead straightforWard. As
`shoWn in FIG. 10, When the car running straightforWard
`ahead is on a level road and has come to a right-turn curve,
`the behavior change of the car ahead turning to the right
`from the reference point S is detected as the front informa
`tion of the vehicle by means of the laser radar mechanism
`40. If the displacement detected With the right-turn behavior
`of the car ahead goes out of the horiZontal dead Zone and into
`the right-turn range (see FIG. 6), the target horiZontal optical
`axis AGx is computed by the equation
`Thus the headlight
`optical axis direction 30 is turned to the right, thereby
`correcting the range of light projection.
`In the correction control of the headlight 30 optical axis,
`the light beam may be Widened to the right instead of
`rightWard correction control of the optical axis. During left
`turns also, the headlight optical axis direction 30 is corrected
`to the left or the light can be Widened to the left. Correction
`control is conducted at predetermined time increments,
`thereby making it possible to set the range of light projection
`of the headlights 30 correspondingly to a behavior change of
`the car ahead and accordingly.
`The vehicle information detecting means preferably
`includes the height sensor 11, car navigation system, etc. for
`detecting various vehicle information such as the
`inclination, movement, acceleration and deceleration of the
`vehicle itself; a laser radar mechanism 40 that detects front
`information; the inclination angle computing means of the
`CPU 21 of the ECU 20 Which computes the inclination angle
`in relation to the headlight optical axis of the vehicle to the
`road surface With reference to an output signal from the
`vehicle information detecting means; the optical axis center
`angle computing means of the CPU 21 of the ECU 20 Which
`computes the center optical axis angle by correcting the
`inclination angle computed by the inclination angle com
`puting means With reference to the front information
`detected by the laser radar mechanism 40; and the optical
`axis adjusting means consisting of the CPU 21 of the ECU
`20, and actuators 35 and 36, for adjusting the headlight
`optical axis direction 30 With reference to the center optical
`axis angle computed by the optical axis center angle com
`puting means. Furthermore, the center optical axis angle is
`computed by the optical axis center angle computing means
`according to the displacement detected, With horiZontal and
`vertical changes in the behavior of a car ahead, as a front
`information supplied from the laser radar mechanism 40.
`The vehicle inclination angle is computed according to an
`output from the height sensor 11. The center optical axis
`angle is corrected and computed according to front infor
`mation given by the car navigation system and the laser
`radar mechanism 40. Then, the headlight optical axis direc
`tion 30 is adjusted relative to the center optical axis angle.
`That is, road information in the direction of travel of a
`vehicle is given by the car navigation system, and front
`information is given by the laser radar mechanism 40. Road
`information and front information such as the presence or
`
`Page 9 of 12
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`US 6,547,425 B2
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`7
`absence of a car ahead, a distance between vehicles, and a
`change in the horizontal and vertical behavior are seen. The
`headlight optical axis direction 30, therefore, can be adjusted
`With reference to the center optical axis angle Which has
`been corrected by a road information given by the car
`navigation system and a behavior change of a car ahead as
`occasion calls, in relation to the inclination angle indicated
`by normal control at Which the headlight optical axis direc
`tion 30 is ?xed 1% (or 1.2%) loWer only by a vehicle
`inclination attitude as a vehicle information from the height
`sensor 11.
`Next, by referring to FIG. 11, a correction control varia
`tion of the headlight optical axis direction 30 by the above
`described control routine Will be described. In FIG. 11, the
`headlights 30 in the present variation are vertically but not
`horiZontally adjustable. That is, the actuator 36 is not
`mounted for the headlights 30 shoWn in FIGS. 1 and 2.
`Supplementary lamps are mounted on the left front/right
`front side of the vehicle.
`As shoWn in FIG. 11, When a car running straightforWard
`ahead on level road approaches a right-turn curve, a right
`Ward change from the reference point S in the behavior of
`the car ahead is detected by the laser radar mechanism 40 as
`the front information of the vehicle. If the displacement
`detected With the rightWard behavior change of the car ahead
`goes out of the horiZontal dead Zone into the right-turn range
`(see FIG. 6), the supplementary lamp (not shoWn) mounted
`on the right front side of the vehicle is turned on While the
`range of light projection of the headlights 30 remains
`unchanged.
`In this case, the brightness of the supplementary lamp
`may be changed based on horiZontal displacement of the car
`ahead and distance betWeen the vehicles. Also, a plurality of
`supplementary lamps may be lit. Similarly, in a left turn, the
`supplementary lamp mounted on the left front side of the
`vehicle is lit. Because the correction control is carried out at
`predetermined time intervals With a behavior change of the
`car ahead, the supplementary lamp is lit to Widen the range
`of light projection corresponding to the behavior change of
`the car ahead Without changing the range of the horiZontal
`light projection of the headlights 30. It is therefore possible
`to improve the driver’s ability to vieW to the direction of turn
`ahead Without blinding the driver of the car ahead.
`In this embodiment, the supplementary lamps (not shoWn)
`mounted on the left front and right front sides of the vehicle
`are turned on to project light to a predetermined range ahead
`according to the right or left turn of the car ahead. When the
`displacement exceeding the predetermined value corre
`sponds to a change in horiZontal behavior of the car ahead
`has been detected as the front information by the laser radar
`mechanism 40 Which functions as the front information
`detecting means, the supplementary lamp turns on corre
`sponding to the turn direction of the vehicle by the optical
`axis adjusting means comprising the CPU 21 of the ECU 20
`and the actuator 35.
`That is, When the displacement exceeds the predetermined
`value corresponding to a change in the horiZontal behavior
`of the car ahead, the corresponding right or left front
`supplementary lamp is lit, thereby Widening the light pro
`jection range. Furthermore, control may be made by com
`bining a headlight adjusting mechanism capable of adjusting
`the vehicle headlights horiZontally and supplementary
`lamps.
`It is noted that the laser radar calculates a distance
`betWeen the car ahead and the present vehicle. If the distance
`does not change during a predetermined time period, it is
`determined that the targeted vehicle is actually a moving
`vehicle and not just an object on the side of the road.
`
`15
`
`25
`
`35
`
`45
`
`55
`
`65
`
`8
`While the above-described embodiments refer to
`examples of usage of the present invention, it is understood
`that the present invention may be applied to other usage,
`modi?cations and variations of the same, and is not limited
`to the disclosure provided herein.
`What is claimed is:
`1. An automatic headlight aiming device for a vehicle,
`comprising:
`a vehicle information detecting means for detecting
`vehicle information that includes information about at
`least one of the inclination, movement, and acceleration
`and deceleration of the vehicle;
`a front information detecting means for detecting infor
`mation in front of the vehicle to be used in conjunction
`With the vehicle information detected by the vehicle
`information detecting means;
`an inclination angle computing means for computing an
`inclination angle of a headlight optical axis With respect
`to a road surface based on the information and output
`from the vehicle information detecting means;
`an optical axis center angle computing means for com
`puting a center angle of the headlight optical axis by
`correcting the inclination angle computed by the incli
`nation angle computing means based on information in
`front of the vehicle detected by the front information
`detecting means;
`an optical axis adjusting means for adjusting the headlight
`optical axis direction With reference to the center
`optical axis angle computed by the optical axis center
`angle computing means according to the information in
`front of the vehicle fed from and detected by the front
`information detecting means;
`a horiZontal adjusting means for horiZontally adjusting the
`optical axis to project light Within a predetermined
`forWard range corresponding to a right or left turn of
`the vehicle; and
`Wherein the optical axis adjusting means adjusts the
`headlight optical axis With the horiZontal adjusting
`means corresponding to a horiZontal vehicle turn When
`a vehicle ahead is displaced by a value Which is outside
`of a predetermined horiZontal dead Zone, the horiZontal
`vehicle turn being front information detected by the
`front information detecting means, and Wherein the
`optical axis adjusting means maintains the headlight
`optical axis With the horiZontal adjusting means When
`the vehicle ahead remains Within the predetermined
`horiZontal dead Zone.
`2. An automatic headlight aiming device according to
`claim 1, Wherein the optical axis center angle computing
`means computes the center angle based on detected hori
`Zontal and vertical displacement of a vehicle ahead as the
`information in front of the vehicle.
`3. An automatic headlight aiming device for a vehicle,
`comprising:
`a vehicle information detecting means for detecting
`vehicle information that includes information about at
`least one of the inclination, movement, and acceleration
`and deceleration of the vehicle;
`a front information detecting means for detecting infor
`mation in front of the vehicle to be used in conjunction
`With the vehicle information detected by the vehicle
`information detecting means;
`an inclination angle computing means for computing an
`inclination angle of a headlight optical axis With respect
`to a road surface based on the information and output
`from the vehicle information detecting means;
`
`Page 10 of 12
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`
`US 6,547,425 B2
`
`an optical axis center angle computing means for com
`puting a center angle of the headlight optical axis by
`correcting the inclination angle computed by the incli
`nation angle computing means based on information in
`front of the vehicle detected by the front information
`detecting means;
`an optical aXis adjusting means for adjusting the headlight
`optical aXis direction With reference to the center
`optical aXis angle computed by the optical aXis center
`angle computing