US00724l034B2
`
`(12) United States Patent
`Smith et al.
`
`(10) Patent No.:
`(45) Date of Patent:
`
`US 7,241,034 B2
`Jul. 10, 2007
`
`1/1978 Martin ..................... .. 362/465
`7/1979 Zillgitt et al.
`. . . . . .
`. . . .. 362/467
`1/1980 Deverrewaere ........... .. 362/466
`------------------- --
`””””””” "
`.
`1/1323 i§*‘;3f§:”:1‘“‘:(“‘..:::...:::::: 33/322
`/
`1.
`13/1322 E2”;‘§?’;f.ff‘ ............ 280/6.158
`8/1988 Kretschmeretal.
`........ .. 362/40
`
`
`
`4,066,886 A
`4,162,424 A
`4,186,428 A
`:
`’
`’
`i1:§i3:?3§ 2
`,
`,
`3323 iii ‘Z
`4,768,135 A
`
`(continued)
`FOREIGN PATENT DOCUMENTS
`
`(54) AUTOMATIC DIRECTIONAL CONTROL
`SYSTEM FOR VEHICLE HEADLIGHTS
`
`(75)
`
`Inventors: James E. Smith, Berkey, OH (US);
`Anthony B. McDonald, Perrysburg,
`0H W
`.
`<73) Asslgneez Dana Corporation, Toledo, 0H (U9
`.
`.
`.
`.
`.
`( * ) Notice:
`Subject to any disclaimer, the term of this
`patent is extended or adjusted under 35
`U'S'C‘ 1540’) by 0 days"
`
`(21) APP1. N04 10/285,312
`
`EP
`
`0306611
`
`3/1989
`
`(22)
`
`Filed:
`
`Oct. 31, 2002
`
`(Continued)
`
`(65)
`
`Prior Publication Data
`US 2003/0107898 A1
`Jun. 12, 2003
`
`1([7r4Smj4r£ioEi:i1C:i/fli:14::tt,At1gi:Atl*2“li\7]'irn—MacMillan, Sobanski &
`Todd, LLC
`
`Related U.S. Application Data
`
`(57)
`
`ABSTRACT
`
`(51)
`
`52
`
`(2006 01)
`'
`(2006.01)
`
`(60) Provisional aPP1iCati0n N0’ .60/369’447’ filed on Apr‘
`2’ 2002’ provlslonal aPP1}°at1°“ N9‘ 69/3563703’ filed
`on Feb‘ 13’ 2002’ provlslonal apphCat1OnN0' 60/335’
`409’ filed on Oct‘ 31’ 2001'
`Int. CL
`B60Q 1/00
`B60R 22/00
`362/465. 701/49
`U S Cl
`3
`' """" “““ “; """"""""""" "
`_'
`'
`)
`(
`(58) Field of Classification Search ................ .. 362/37,
`362/46574663 315/823 701/49
`See applieatien file for eemplete Search hi5t01'Y-
`References Cited
`
`(56)
`
`U.S. PATENT DOCUMENTS
`3,634,677 A
`1/1972 Stuttgart et al.
`............ 362/467
`
`3,939,339 A
`2/1976 Alphen ............... .. 362/467
`
`3,953,726 A
`4/1976 Scarritt, Sr.
`..
`362/465
`5/1977 Skoif ....................... .. 362/467
`4,024,388 A
`
`A structure and method for operating a directional control
`system for Vehicle headlights that is capable of altering the
`directional aiming angles of the headlights to account for
`changes in the operating conditions of the Vehicle. One or
`more ci)peratin1gte1oitidition sensotrstimayfbe pg)‘:/iided fthfiit
`genera e signa s
`a are represen a iVe o a con 1 ion o i e
`Vehicle, such as road speed, steering angle, pitch, suspension
`.
`height, rate of change of road speed, rate of change of
`steering angle, rate of change of pitch, and rate of change of
`suspension height of the Vehicle. A eemiehei is responsive
`to the sensor signal for generating an output signal. An
`actuator is adapted to be connected to the headlight to effect
`movement thereofin accordance with the output signal. The
`controller can include a table that relates Values of sensed
`
`operating condition to Values of the output signal. The
`Cfintroller iS.reS1i°.nSiEe tobtihe Sensor Signal for lookmg up
`t e Output 51%“ mt eta e~
`
`5 Claims, 7 Drawing Sheets
`
`12
`UP/DOWN
`ACTUATOR
`
`1K
`
`POSITION
`FEEDBACK «T
`SENSOR
`
` HEADLIGHT
`
`DIRECTIONAL
`CONTROLLER
`
`INPUT/OUTPUT
`DEVICE
`CONDITION
`SENSOR
`CONDITION
`SENSOR
`
`KOITO 1004
`
`1
`
`KOITO 1004
`
`

`
`US 7,241,034 B2
`Page 2
`
`U. S. PATENT DOCUMENTS
`
`4,791,343
`4,833,573
`4,868,720
`4,868,721
`4,870,545
`4,891,559
`4,907,877
`4,908,560
`4,916,587
`4,943,893
`4,948,249
`5,060,120
`5,099,400
`5,158,352
`5,164,785
`5,181,429
`5,193,894
`5,331,393
`5,373,357
`5,3921 11
`5,404,278
`5,426,571
`5,428,512
`5,485,265
`5,526,242
`5,550,717
`5,633,710
`5,660,454
`5,707,129
`5,751,832
`5,779,342
`
`>>>D>D>>i1>U>3>>J>J>U>U>D>U>U>U>L\>>>>C'>D>>>3>D>J>D>J>
`
`I2/1988 Ahrendt .................... .. 362/348
`5/1989 Miyauchi et al.
`.. 362/466
`9/1989 Miyauchi et al.
`362/466
`9/1989 Soardo ..................... .. 362/466
`9/1989
`7aLanaka el al.
`315/82
`1/1990 Malsumoto el al.
`356/121
`3/1990
`fiukuda et a1.
`............ .. 318/603
`3/1990
`hibata et a1.
`.. 318/603
`4/1990
`irose et al.
`............. .. 362/460
`7/1990
`hibata et a1.
`.............. .. 362/37
`8/1990
`opkins et a1.
`.. 356/121
`10/1991
`{obayashi et 31.
`.. 362/465
`3/1992
`~
`362/37
`~
`10/1992
`~ 362/359
`opkins ct a1.
`11/ 1992
`-- 356/121
`1/1993 Sieber
`~ 74/89-42
`.-
`3/1993
`Jietar et 31-
`-- 362/466
`7/1994
`70p1<ins et a1.
`~ 356/121
`12/1994
`*0p1<i11seta1.
`~- 356/121
`2/1995 Mumm 6181-
`-- 356/121
`4/1995 Shibma CT 211.
`.. 362/464
`6/1995 Jones ~~~~~~~~~~~~~~~~~~~~~~~ ~~ 362/466
`5/1995 Moms
`352/466
`1/1996 Hopkins
`-- 356/121
`6/1996 Takahashi et 21.
`362/466
`8/1996 Liao ..... ..
`362/467
`
`~
`
`~
`
`.
`
`3>>>>D>>>D>D>D>D>>D>>>>
`
`............... .. 340/468
`7/1998 Bitar et a1.
`5.781.105
`7/1998 Huhn ....................... .. 362/459
`5,785.405
`2/1999 Speak et al.
`.
`.. 362/37
`553631438
`..
`3/1999 Okuchi ct al.
`340/468
`5.3771680
`4/1999 Zillgitt
`..................... .. 340/468
`5396011
`5/1999 Hayami et al.
`.. 307/10.8
`5907.196
`6/1999
`55909949
`............. .. 356/121
`7/1999 Panter et a1.
`55920386
`362/459
`8/1999 Hege ......... ..
`55933319
`11/1999 Miller er al. .............. .. 310/103
`5,977‘67g
`1/2000
`362/460
`6 010337
`4/2000 Kobayashi
`701/49
`65491749
`8/2000 Diep ......... ..
`. 315/82
`6091156
`9/2000 Hibbard et al.
`250/205
`6,118,113
`11/2000 Zillgitt et a1.
`362/466
`6,142,655
`11/2000 Lopez et a1.
`.. 315/82
`6,144,159
`1/200
`Prevost et al.
`.. 362/37
`6,176,590
`2/200
`Toda et al.
`..
`362/465
`6,183,118
`2/200 Okuchi et :11.
`362/466
`6,193,398
`5/200 Hogrefe et :11.
`362/539
`6,227,691
`5/200
`Frasch ....... ..
`362/464
`6,231,216
`5/200 Okuchi e161.
`362/466
`6,234,654
`8/200
`Stam 61 a1.
`315/82
`652111.632
`9/200 Hayami ct al.
`362/465
`6,293,686
`6,305,823 131* 10/200
`Toda etal.
`362/276
`2001/0019225 A1
`9/200
`Toda etal.
`
`.
`
`.
`
`FOREIGN PATENT DOCUMENTS
`
`362/464
`5/1997 Kumra
`8/1997 Mori et al.
`................ .. 362/464
`1/1998 Kobayashi
`.
`.. 362/104
`5/1998 Panter et al.
`7/1998 Kluge ...................... .. 362/507
`
`M42757
`E1,
`-
`.
`5333;;
`5;;
`* cited by examiner
`
`10/2001
`,
`1,3333
`
`2
`
`

`
`U.S. Patent
`
`Jul. 10, 2007
`
`Sheet 1 of7
`
`US 7,241,034 B2
`
`"\
`
`UP/DOWN
`ACTUATOR
`
`POSITION
`FEEDBACK
`SENSOR
`
`POSITION
`FEEDBACK
`SENSOR
`
`INPUT/OUTPUT
`DEVICE
`
`CONDITION
`SENSOR
`
`CONDITION
`SENS OR
`
`LEFT/RIGHT
`ACTUATOR
`
`HEADLIGHT
`DIRECTIONAL
`CONTROLLER
`
`3
`
`

`
`U.S. Patent
`
`Jul. 10, 2007
`
`Sheet 2 of 7
`
`US 7,241,034 B2
`
`ENTER CALIBRATION
`
`MODE
`
`MANUALLY OPERATE
`
`ACTUATORS TO AIM
`
`HEADLIGHT IN
`
`REFERENCE ORIENTATION
`
`l
`
`STORE POSITION IN
`HEADLIGHT DIRECTIONAL /— 23
`CONTROLLER AS
`
`REFERENCE POSITION
`
`4
`
`

`
`U.S. Patent
`
`Jul. 10, 2007
`
`Sheet 3 of 7
`
`US 7,241,034 B2
`
`SELECT ADJUSTMENT
`
`CONTROL ALGORITHM
`
`GENERATE TABLE OF
`
`CONDITION VS.
`
`ADJUSTIVIENT CONTROL
`
`VALUES
`
`STORE TABLE IN
`
`HEADLIGHT DIRECTIONAL
`
`CONTROLLER
`
`5
`
`

`
`U.S. Patent
`
`Jul. 10, 2007
`
`Sheet 4 of 7
`
`US 7,241,034 B2
`
`SENSED CONDITION ”
`(STEERING ANGLE)
`VALUES
`
`UP/DOWN
`ADJUSTMENT
`FACTORS
`
`LEFT/RIGHT
`ADIUSTMENT
`FACTORS
`
`-450°
`
`6
`
`

`
`U.S. Patent
`
`Jul. 10, 2007
`
`Sheet 5 of 7
`
`US 7,241,034 B2
`
`READ VALUE OF
`CONDITION SENSOR
`
`IS CONDITION
`SENSOR VALUE
`IN TABLE?
`
`LOOKUP ADJUSTMENT
`FACTORS IN TABLE FOR
`SENSED CONDITION
`SENSOR VALUE
`
`LOOKUP ADJUSTMENT
`FACTORS IN TABLE FOR
`ADJACENT CONDITION
`SENSOR VALUES
`
`INTERPOLATE
`ADIUSTIVLENT FACTOR
`
`COMPARE ADJUSTMENT
`FACTORS WITH CURRENT
`HEADLIGHT POSITION
`
`I\/LAGNITUDE OF
`ADJUSTMENT
`GREATER THAN
`THRESHOLD?
`
`YES
`
`ENERGIZE HEADLIGHT
`ACTUATORS
`
`7
`
`

`
`U.S. Patent
`
`Jul. 10, 2007
`
`Sheet 6 of 7
`
`US 7,241,034 B2
`
`READ FIRST VALUE OF
`
`CONDITION SENSOR
`
`READ SECOND VALUE OF
`
`CONDITION SENSOR
`
`CALCULATE RATE OF
`
`CHANGE OF SEN SED
`
`CONDITION
`
`ENERGIZE HEADLIGHT
`
`ACTUATORS
`
`8
`
`

`
`U.S. Patent
`
`Jul. 10, 2007
`
`Sheet 7 of 7
`
`US 7,241,034 B2
`
`70
`
`4/
`
`READ FIRST VALUE OF
`
`CONDITION SENSOR
`
`READ SECOND VALUE OF
`CONDITION SENSOR
`
`CALCULATE RATE OF
`
`CILANGE OF SENSED
`CONDITION
`
`IS RATE OF
`CHANGE LESS
`THAN
`
`THRESHOLD?
`
`ENERGIZE HEADLIGHT
`
`ACTUATORS
`
`9
`
`

`
`US 7,241,034 B2
`
`1
`AUTOIVIATIC DIRECTIONAL CONTROL
`SYSTEM FOR VEHICLE HEADLIGHTS
`
`CROSS Rl_Il"IJRIJNCIj TO RIJLATIJD
`APPLICATIONS
`
`This application claims the benefit of US. Provisional
`Application Nos. 60/335,409, filed Oct. 31, 2001; 60/356,
`703, filed Feb. 13, 2002; and 60/369,447, filed Apr. 2, 2002,
`the disclosures of wl1icl1 are incorporated herein by refer-
`ence.
`
`BACKGROUND OF THE INVENTION
`
`'lhis invention relates in general to headlights that are
`provided on vehicles for illuminating dar< road surfaces or
`other areas in the path of movement. In particular,
`this
`invention relates to an automatic directional control system
`for such vehicle headlights.
`Virtually all
`land vehicles, and many other types of
`vehicles (such as boats and airplanes, for example), are
`provided with one or more headlights that are adapted to
`illuminate a portion of a dark road surface or other area in
`the path of movement of the vehicle to facilitate safe travel
`thereon. Typically, each headlight is mounted on or near the
`front end of the vehicle and is oriented ir1 such a mamier that
`a beam of light is projected forwardly therefrom. The angle
`at which the beam of light projects from the headlight can,
`for example, be characterized in a variety of ways, including
`(1) up and down relative to a horizontal reference position , ,
`or plane and (2) left and right relative to a vertical reference
`position or plane. Such directional aiming angles are usually
`set at the time of assembly of the headlight into the vehicle
`so as to illuminate a predetermined portion of the road
`surface or other area in the path of movement of the vehicle.
`In the past, these headlights have been mounted on the
`vehicle in fixed positions relative thereto such that the beams
`of light are projected therefrom at predetermined directional
`aiming angles relative to the vehicle. Although such fixed
`aiming angle headlight systems have and continue to func-
`tion adequately,
`they cannot alter the directional aiming
`angles of the headlights to account for changes in the
`operating conditions of the vehicle.
`I"or example, if the
`speed of the vehicle is increased, it would be desirable to
`adjust the aiming angle of the headlights upwardly such that
`an area that is somewhat farther ir1 front of the vehicle is
`more brightly illuminated. On the other hand, if the speed of
`the vehicle is decreased, it would be desirable to adjust the
`aiming angle of the headlights downwardly such that an area
`that
`is somewhat closer in front of the vehicle is more
`brightly illuminated. Similarly, if the vehicle turns a corner,
`it would be desirable to adjust
`the aiming angle of the
`headlights either toward the left or toward the right (depend-
`ing on the direction of the turn) such that an area that is
`somewhat lateral to the front of the vehicle is more brightly
`illuminated.
`To accomplish this, it is known to provide a directional
`control system for vehicle headlights that
`is capable of
`automatically altering the directional aiming angles of the
`headlights to account for changes in the operating conditions
`of the vehicle. A variety of such automatic directional
`control systems for vehicle headlights are known in the art.
`I Iowever, such known automatic headlight directional con-
`trol systems have been found to be deficient for various
`reasons. Thus, it would be desirable to provide an improved
`structure for an automatic headlight directional control sys-
`tem that addresses such deficiencies.
`
`2
`SUMMARY OF THE INVENTION
`
`This invention relates to an improved structure and
`method for operating a directional control system for vehicle
`headlights that
`is capable of automatically altering the
`directional aiming angles of the headlights to account for
`changes in the operating conditions of the vehicle. One or
`more operating condition sensors may be provided that
`generate signals that are representative of an operating
`condition of the vehicle, such as road speed, steering angle,
`pitch, suspension height, rate of change of road speed, rate
`of change of steering angle, rate of change of pitch, and rate
`of change of suspension height of the Vehicle. A controller
`is responsive to the sensor signal for generating an output
`signal. An actuator is adapted to be connected to the head-
`light to effect movement thereof in accordance with the
`output signal. The controller can include a table that relates
`values of sensed operating condition to values of the output
`signal. The controller is responsive to the sensor signal for
`looking up the output signal in the table.
`Various objects and advantages of this invention will
`become apparent to those skilled in the art from the follow-
`ing detailed description of the preferred embodiments, when
`read in light of the accompanying drawings.
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`
`FIG. 1 is a block diagram of an automatic directional
`control system for a vehicle headlight in accordance with
`this invention.
`FIG. 2 is a flow chart of an algorithm for calibrating the
`automatic directional control system illustrated in FIG. 1 so
`as to define an imtial reference position for the headlight
`from which the headlight directional controller can imple-
`, ment directional angle adjustments.
`FIG. 3 is a flow chart of a11 algorithm for generating a
`table that relates one or more sensed vehicle operating
`condition values to one or more headlight directional angle
`adjustment factors and for storing such table in the headlight
`directional controller illustrated in FIG. 1.
`FIG. 4 is an example ofa table that can be generated and
`stored in the headlight directional controller in accordance
`with the table generating algorithm illustrated in FIG. 3.
`FIG. 5 is a flow chart of an algorithm for operating the
`headlight directional controller illustrated in FIG. 1 to auto-
`matically implement directional angle adjustments in accor-
`dance with sensed condition values.
`
`FIG. 6 is a flow chart of an algorithm for operating the
`headlight directional controller illustrated in FIG. 1 to auto-
`matically implement directional angle adjustments in accor-
`dance with the rate of change of one or more of the sensed
`condition values.
`
`FIG. 7 is a flow chart of ar1 algorithm for operating the
`headlight directional controller illustrated in FIG. 1 to auto-
`matically implement directional angle adjustments, but only
`when the rate of change of one or r11ore of the sensed
`condition values is less than (or greater than) a predeter-
`mined value.
`
`DETAILED DESCRIPTION OF TH:
`PREFERRED EMBODIMENTS
`
`Referring now to the drawings, there is illustrated in I'I('r.
`1 an automatic directional control system, indicated gener-
`ally at 10, for a vehicle headlight 11 in accordance with this
`invention. The illustrated headlight 11 is, of itself, conven-
`tional in the art and is intended to be representative of any
`
`10
`
`

`
`US 7,241,034 B2
`
`3
`device that can be supported on any type of vehicle for the
`purpose of illuminati11g any area, such as an area in the path
`of movement of the vehicle. The headlight 11 is typically
`mounted on or near the front end of a vehicle (not shown)
`and is oriented m such a manner that a beam of light is
`projected therefrom. In a manner that is well known in the
`art, the headlight 11 is adapted to illuminate a portion of a
`dark road surface or other area in the path of movement of
`the vehicle to facilitate safe travel thereon.
`The headlight 11 is adjustably mounted on tl1e vehicle
`such that the directional orientation at which the beam of
`light projects therefrom can be adjusted relative to the
`vehicle. Any desired mounting structure can be provided to
`accomplish this. Typically, the headlight 11 is mounted on
`the vehicle such that the angle at Wl1icl1 the beam of ligl1t
`projects therefrom can be adjusted both (1) up and down
`relative to a horizontal reference position or plane and (2)
`left and right relative to a vertical reference position or
`plane. Although this invention will be described and illus-
`trated in the context of a headlight that is adjustable in both
`the up/down direction and the left/right direction, it will be
`appreciated that this invention may be practiced with any
`headlight 11 that is adjustable in any single direction or
`multiple directions of movement, whether up/dow11, left/
`right, or any other direction.
`To effect movement of the illustrated headlight 11 relative
`to the vehicle, an up/down actuator 12 and a left/right
`actuator 13 are provided. The actuators 12 and 13 are
`conventional iii the art and may, for example, be embodied
`as servo motors, step motors, or any other electronically ,,
`controlled mechanical actuators. It has been found to be
`desirable to use microstcpping motors for the actuators 12
`and 13. Such micro stepping motors are known in the art and
`consist of conventional step motors that have appropriate
`hardware (i.e., driver integrated circuits) and sofiware that
`allow the step motors to be operated in fractional step
`increments. The use of such microstcpping motors has been
`found to be desirable because they can effect movements of
`the headlights in a somewhat faster, smoother, and quieter
`manner than conventional step motors, a11d further permit
`more precise positioning of the headlights 11. In the illus-
`trated embodiment, the up/down actuator 12 is mechanically
`coimected to the headlight 11 such that the headlight 11 can
`be selectively adjusted up and down relative to a horizontal
`reference position or plane. Similarly, the illustrated left/
`right actuator 13 is mechanically connected to the headlight
`11 such that the headlight 11 can be selectively adjusted left
`and right relative to a vertical reference position or plane.
`A headlight directional controller 14 is provided for
`controlling the operations of the up/down actuator 12 and
`the leftjright actuator 13 and, therefore, the angle at which
`the beam of light projects from the headlight 11 relative to
`the vehicle. The headlight directional controller 14 can be
`embodied as any control system, such as a microprocessor
`or programmable electronic controller, that is responsive to
`one or more sensed operating conditions of the vehicle for
`selectively operating the up/down actuator 12 and the left/
`right actuator 13. To accomplish this, the automatic direc-
`tional control system 10 can include, for example, a pair of
`condition sensors 15 and 16 that are connected to the
`headlight directional controller 14. The condition sensors 15
`and 16 are conventional in the art and are responsive to
`respective sensed operating conditions of the vehicle for
`generating electrical signals to the headlight directional
`controller 14. However, if desired, only a single one of the
`condition sensors 15 and 16 need be provided. Alternatively,
`additional condition sensors (not shown) may be provided if
`
`4
`desired to generate electrical signals that are representative
`of any other operating conditions of the vehicle. A conven-
`tional
`input/output device 17 is connected to (or can be
`connected to) the headlight directional controller 14 for
`facilitating
`communication therewith in the manner
`described below.
`
`If desired, a first position feedback sensor 18 may be
`provided for the up/down actuator 12, a11d a second position
`feedback sensor 19 may be provided for the left’right
`actuator 13. The position feedback sensors 18 and 19 are
`conventional in the art a11d are adapted to generate respec-
`tive electrical signals that are representative of the actual
`up/down a11d left/right positions of the headlight 11. Thus,
`the first position feedback sensor 18 is responsive to the
`actual up/down position of the headlight 11 (as determined
`by a portion of the up/down actuator 12, for example) for
`generating an electrical signal to the headlight directional
`controller 14 that is representative thereof. Similarly,
`the
`second position feedback sensor 19 is responsive to the
`actual left/right position of the headlight 11 (as determined
`by a portion of the left/right actuator 13, for example) for
`generating an electrical signal to the headlight directional
`controller 14 that is representative thereof. The position
`feedback sensors 18 and 19 can be embodied as any con-
`ventional sensor structures, such as Hall effect sensors, that
`are responsive to movements of the headlight 11 (or to the
`movements of the respective actuators 12 a11d 13 that are
`connected to move the headlight 11) for generating such
`signals.
`Altematively, the position feedback sensors 18 and 19 can
`be embodied as respective devices that generate electrical
`signals Whenever the headlight 11 l1as achieved respective
`predetermined up/down or left/right positions. This can be
`. accomplished, for example, using a conventional optical
`interrupter (not shown) for each of the actuators 12 and 13.
`Each of the optical
`interrupters includes a flag or other
`component that is mounted on or connected to the headlight
`11 for movement therewith. Each of the optical interrupters
`further includes an optical source and sensor assembly. As
`the headlight 11 is moved by the actuators 12 and 13, the flag
`moves therewith relative to the optical source and sensor
`assembly between a first position, wherein the flag permits
`light emitted from the source from reaching the sensor, and
`a second position, wherein the flag prevents light emitted
`from the source from reaching the sensor. When the [lag is
`in the first position relative to the optical source and sensor
`assembly, the sensor is pemiitted to receive light emitted
`from the source. As a result, a first signal is generated from
`the optical source and sensor assembly to the headlight
`directional controller 14, Conversely, when the flag is in the
`second position relative to the optical source and sensor
`assembly, the sensor is not permitted to receive light emitted
`from the source. As a result, a second signal is generated
`from the optical source and sensor assembly to the headlight
`directional controller 14. Thus, the edge of the flag defines
`a transition between the first and second positions of the flag
`relative to the optical source and sensor assembly and,
`therefore, defines a predetermined up/down or lefL’right
`position of the headlight 11. The nature of the signal
`generated from the optical source and sensor assembly to the
`headlight directional controller 14 (i.e., the first signal or the
`second signal) can also be used to determine on which side
`of the predetermined position (the left side or the right side,
`for example) that the headlight 11 is positioned. The purpose
`for such position feedback sensors 18 and 19 will be
`discussed below.
`
`11
`
`

`
`US 7,241,034 B2
`
`5
`FIG. 2 is a flow chart of an algorithm, indicated generally
`at 20, for calibrating the automatic directional control sys-
`tem illustrated i11 FIG. 1 so as to define an initial reference
`position or positions for the headlight 11 from which the
`headlight directional controller 14 can implement direc-
`tional angle adjustments. As mentioned above, the headlight
`11 is mounted on the vehicle such that the angle at which the
`beam of light projects therefrom can be adjusted both up and
`down relative to a horizontal reference position or plane and
`left and right relative to a vertical reference position or
`plane. To insure accurate positioning of the headlight 11, it
`is desirable that a reference position or positions be initially
`established by the headlight directional controller 14. Sub-
`sequent directional angle adjustments can be made by the
`headlight directional controller 14 from the pre-established
`reference position or positions established by this calibration
`algorithm 20.
`To accomplish this, the calibration algorithm 20 has a first
`step 21 wherein the headlight directional controller 14 is
`caused to enter a calibration mode of operation. In the
`calibration mode of operation,
`the headlight directional
`controller 14 is responsive to input signals from the input/
`output device 17 (or from another source, if desired) for
`causing manual operation of the up/down actuator 12 and
`the left/right actuator 13. Thus, while the headlight direc-
`tional controller 14 is in the calibration mode of operation,
`an operator ofthe input/output device 17 can manually elfect
`either up/down movement of the headlight 11,
`left/right
`movement of the headlight 11, or both, as desired.
`In a second step 22 of the calibration algorithm 20, the ,,
`up/down actuator 12 and the left/right actuator 13 are
`manually operated to aim the headlight 11 in a predeter-
`mined reference orientation. This can be accomplished by
`use of the input/output device 17 that, as mentioned above,
`is connected to (or can be connected to) the headlight
`directional controller 14. Traditionally,
`the aiming of a
`headlight 11 has been accomplished by parking the vehicle
`on a surface near a wall or other vertical structure, providing
`a reference target at a predetermined location on the wall or
`other structure, and mechanically adjusting the mounting
`structure of the headlight 11 such that the center of the beam
`tierefrom is projected at the reference target. In this inven-
`tion, the vehicle is parked 011 a surface near a wall or other
`vertical structure, and a reference target is provided at a
`predetermined location on the wall or other structure, as
`L€SCI'IlZ)6(.l above. Next, in accordance with the second step
`22 of this calibration algorithm 20, the input/output device
`17 is operated to generate electrical signals to the headlight
`cirectional controller 14. In response to such electrical
`signals, the headlight directional controller 14 operates the
`up/down actuator 12 and the lefi/right actuator 13 to move
`tie headlight 11 such that center of the beam projecting
`t1erefron1 is aimed at the reference target. When the beam
`from the headlight 11 is so aimed, then the headlight 11 is
`cetermined to be oriented in the initial reference position
`from wl1icl1 the headlight directional controller 14 can
`subsequently implement directional angle adjustments.
`In a third step 23 ofthe calibration algorithm 20, once this
`initial reference position for the headlight 11 has been
`achieved, such position is stored in the headlight directional
`controller 14 as the predetermined initial reference position.
`This can be accomplished by means of the position feedback
`sensors 18 and 19. As discussed above, the position feed-
`back sensors 18 and 19 are adapted to generate respective
`electrical
`signals that are representative of the actual
`up/dowr1 and left/right positions of the headlight 11 or of the
`predetermined positions for the headlight. Thus, the first
`
`6
`position feedback sensor 18 is responsive to the actual
`up/down position of the headlight 11 (as determined by the
`up/down actuator 12, for example) for generating an elec-
`trical signal to the headlight directional controller 14 that is
`representative thereof. Similarly, the second position feed-
`back sensor 19 is responsive to the actual left/right position
`of the headlight 11 (as determined by the left/right actuator
`13, for example) for generating an electrical signal to the
`headlight directional controller 14 that
`is representative
`thereof. Accordingly, the third step 23 of the calibration
`algorithm 20 can be performed by causing the headlight
`directional controller 14 to read the signals from the position
`feedback sensors 18 and 19 and store the current up/down
`and left/right positions of the headlight 11 as the initial
`reference positions from which the headlight directional
`controller 14 can subsequently implement directional angle
`a dj u stments .
`The current position of the headlight 11 is preferably
`stored in the 11on—volatile memory of the headlight direc-
`tional controller 14 for reference during normal operation of
`the automatic directional control system 10 described below.
`Thus, when the automatic directional control system 10 is
`initially activated (such as when the electrical system of the
`vehicle is initially turned on),
`the headlight directional
`controller 14 can position the headlight 11 at or near the
`calibrated position utilizing the signals comparing the cur-
`rent position of the headlight 11 (as determined by the
`signals generated by the position feedback sensors 18 and
`19) with the predetermined reference position determined by
`the calibration algorithm 20.
`FIG. 3 is a flow chart of a11 algorithm. indicated generally
`at 30, for generating a table that relates the sensed condition
`values fror11 the condition sensors 15 and 16 to the headlight
`directional angle adjustment factors that will be imple-
`. mented by the headlight directional controller 14, and fur-
`ther for storing such table in the headlight directional
`controller 14 illustrated in FIG. 1. As used herein, the term
`“table” is intended to be representative of any collection or
`association of data that relates one or more of the sensed
`condition values to one or more of the headlight directional
`angle adjustment factors. The table of data can be generated,
`stored, and expressed in any desired format. For example,
`this table of data can be generated, stored, and expressed in
`a conventional spreadsheet format, such as shown i11 FIG. 4.
`which will be discussed in detail below.
`In a fII'Sl step 31 of the table generating algorithm 30, an
`adjustment control algorithm is selected. The adjustment
`control algorithm can be, generally speaking, any desired
`relationship that relates one or more operating conditions of
`the vehicle to one or more angular orientations of the
`headlight 11. A variety of such relationships are known in
`the art, and this invention is not intended to be limited to any
`particular relationship. Typically, such relationships will be
`expressed in terms of a mathematical equation or similar
`relationship that can be readily processed using a micropro-
`cessor or similar electronic computing apparatus, such as the
`above—described headlight directional controller 14. The
`particular adjustment control algorithm that is selected may,
`if desired, vary fron1 vehicle to vehicle in accordance with
`a variety of factors, including relative size and performance
`characteristics of the vehicle or any other desired condition.
`As mentioned above, a plurality of operating conditions
`may be sensed by the condition sensors 15 and 16 and
`provided to the headlight directional controller 14 for use
`with the adjustment control mechanism. For example, the
`condition sensors 15 and 16 may generate electrical signals
`to the headlight directional controller 14 that are represen-
`
`12
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`US 7,241,034 B2
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`5
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`7
`tative of the road speed, the steering angle, and the pitch of
`the vehicle (which can, for example, be determined by
`sensing the front and rear suspension heights of the vehicle
`or by a pitch or level sensor). Additionally, the time deriva-
`tive of these operating conditions (i.e., the rate of change of
`the road speed, steering angle, a11d pitch of the vehicle) can
`be sensed or calculated.
`IIowever, any other operating
`condition or conditions of the vehicle may be sensed and
`provided to the headlight directional controller 14.
`In a second step 32 of the table generating algorithm 30,
`the table is generated using the adjustment control algorithm
`selected in the first step 31 . The table can be generated in any
`desired manner. For example,
`let it be assumed that the
`selected adjustment control algorithm relates a single sensed
`opera ing condition to each of the angular adjustment con-
`trol values for adjusting both the up/down orientation and
`the le t/right orientation ofthe headlight 11. The table can be
`generated by initially selecting a first discrete sensed oper-
`ating condition value that might be encountered during
`opera ion of the vehicle. Then,
`the selected adjustment
`control algorithm is solved using such first discrete sensed
`opera ing condition value to obtain the corresponding
`adjustment control values for the up/down and left/right
`orientation of the headlight 11. Then, the first discrete sensed
`opera ing condition value and the corresponding adjustment
`control values are stored in the table. This process can be
`repeated for any desired number of other discrete sensed
`opera ing condition values that might be encountered during
`opera ion of the vehicle.
`As mentioned above, FIG. 4 is a representative example , ,
`of a table, indicated generally at 40, that can be generated in
`accordance with the second step 32 of the table generating
`algorithm 30 illustrated ir1 FIG. 3. As shown therein, a series
`of discrete sensed operati11g condition values (degrees of
`steering angles,
`for example) is related to the angular
`adjustment control values (degrees of movement from the
`associated up/down and left/right reference positions or
`planes, for example) for adjusting botl1 the up/down orien-
`tation and the left/right orientation of the headlight 11. For
`the purposes of illustration only, let it be assumed that (1) a
`positive steering angle value represents steering toward left,
`while a negative steering angle value represents steering
`toward the right, (2) a positive up,’down adjustment factor
`represents aiming the headlight 11 upwardly, while a nega-
`tive up/down adjustment factor repr