(12)UK Patent Application ....GB (mz 309 773 (13)A
`
`(43) Date of A Publication 06.08.1997
`
`(21) Application No 97013212
`
`(22) Date of Filing 29.01.1997
`
`(30) Priority Data
`(31)
`08037109
`
`(32) 01.02.1996
`
`(33)
`
`JP
`
`(51)
`
`INT CL‘
`B60Q1I115
`
`(52) UK CL (Edition 0)
`F4R RMC R364 R41V R765 R78X R789
`U15 S1934
`
`_
`_
`App|If=ant(sl
`Konto Manufacturing CO.. Ltd.
`
`(Incorporated in Japan)
`
`8-3, Takanawn 4-chome, Minato-ku, Tokyo, Japan
`Inventorlsl
`Hiduki Uchida
`
`Agent and/or Address for Service
`Gill Jennings & Every
`Broadgate House. 7 Eldon Street. LONDON,
`EC2M 7LH. United Kingdom
`
`(56) Documents Cited
`EP 0709240 A2
`032053439 A
`Ep 0652134 A1 W0 96/13524 A1
`
`EP 0699559 A1
`
`(53) maid of Search
`UK CL (Edition 0 I Hi! RMC
`INT ci_5 35001/as 1/10 1/105 1/11 1/115
`Online : WPI, CLAIMS, JAPIO
`
`(54) controlling direction of vehicle lights
`
`(57) The illumination direction of lights in a vehicle is controlled by detecting (1) vehicle posture (stationary
`and/or moving) and (2) whether the vehicle is accelerating] decelerating and directing the illumination of the
`lights to a predetermined direction in accordance with signals received from the posture detection device. The
`signals to the drive means are over-ridden when acceleration/deceleration is detected in order to fix the lights
`in a predetermined direction and/or limit the permitted range of light movement and/or slow the speed 01
`direction change. Reference values may be used to determine whether and what direction change occurs. The
`system may include means to distinguish true acceleration/deceleration from vehicle movements caused by
`rough roads.
`
`1
`”\.
`
`2
`
`VEHICLE POSTURE
`DETECTTON DEVICE
`
`7
`
`VEHICLE SPEED DETECTION
`DEVICE
`
`8
`
`ACCELERATION OR
`DECELERATION INSTRUCTION
`DETECTION DEVICE
`
`ENGINE REVOLUTION
`NUMBER DETECTION
`DEVICE
`
`CORRECTION
`
`ggL,f(§’E”"'"°
`
`ACCELERATION
`OR DECELERATION
`RUNNING CONDITION
`JUDGING DEVICE
`
`DRIVE
`MECHANISM
`
`At least one drawing originally filed was informal and the print reproduced here is taken from a later filed formal copy.
`SL Corp. Exhibit 1022
`
`VEAL608Z89
`
`

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`
`VEHICLE SPEED IS
`DETECTED
`
`ACCELERATION OR
`ITS ABSOLUTE VALUE
`IS DETECTED
`
`IS
`CALCULATED VALU
`EQUAL OR MORE THAN
`REFERENCE
`VALUE?
`
`IT IS JUDGED THAT VEHICLE IS
`IN ACCELERATION OR
`DECELERATION RUNNING
`CONDITION
`
`IT IS JUDGED THAT VEHICLE IS
`NOT IN ACCELERATION OR
`DECELERATION CONDITION
`
`

`
`

`
`

`
`EnluVEDENRD
`
`

`
`

`
`DRIVE DEVICE
`
`DRIVE DEVICE
`
`

`
`DRIVE DEVICE
`
`

`
`2309773
`
`A VEHICLE LAMP ILLUMINATION DIRECTION CONTROL DEVICE
`
`lamp
`to a vehicle
`invention relates
`The present
`illumination direction control device which detects the posture
`of a vehicle and correctly adjusts the illumination direction
`
`of a vehicle lamp so that
`
`the illumination direction can be
`
`alwavs kept in a predetermined direction.
`
`there has been known a device (a so
`Conventionally,
`called automatic
`leveling device) which,
`even when
`the
`a
`inclination of
`vehicle
`body varies,
`is
`capable
`of
`automatically adjusting the illumination direction of
`the
`
`vehicle lamp so that the illumination direction of the vehicle
`
`lamp
`
`can
`
`be
`
`kept
`
`at
`
`a
`
`predetermined direction.
`
`The
`
`conventional device of this type includes a detection device
`which detects the inclination and height of the vehicle body
`variable according to the conditions of occupants (such as the
`number of occupants,
`the position arrangement of the occupants
`and the like),
`the loaded conditions of
`loads on board the
`
`the running conditions of the vehicle, and the like,
`vehicle,
`calculates the amount of variations in the inclination of the
`vehicle based on the information that
`is obtained by the
`detection device, and adjusts the illumination angle of
`the
`vehicle lamp with respect to the initially adjusted value of
`the vehicle lamp so that the illumination state of the vehicle
`lamp can be always kept in a desired state,
`thereby to control
`the illumination direction of
`the vehicle lamp for desired
`light distribution.
`
`For example, when a load is applied to the rear portion
`of the vehicle,
`the device finds the then inclination angle of
`the vehicle body in the longitudinal direction thereof, and
`inclines the vehicle lamp downward because the illumination
`
`

`
`direction of which would be displaced upwardly of the reference
`direction if the posture of the vehicle lamp is left as it is,
`thereby adjusting the illumination direction of
`the vehicle
`lamp (a so called leveling adjustment) so that the vehicle lamp
`illumination direction can be always kept
`in the reference
`direction.
`
`in the above-mentioned conventional device,
`However,
`while the vehicle is running along a rough road including an
`uneven and rough surface, when the device makes
`the above-
`mentioned automatic adjustment of the illumination direction of
`the vehicle lamp,
`there is a possibility that
`the detection
`device can respond excessively to the illumination direction of
`the vehicle lamp and thus the illumination direction of
`the
`vehicle lamp can be controlled or adjusted excessively, which
`causes the light distribution of the vehicle lamp and the field
`of view to vary. Such variations in the light distribution and
`visibility in turn can give a driver a strange feeling, or can
`dazzle the driver of an oncoming vehicle, a pedestrian, and the
`like.
`
`For example, when the vehicle runs into a rough road at
`a rather high speed, vibrations and the like applied to the
`vehicle wheels from the surface of the rough road are relieved
`by the expansion and contraction of
`the suspension of
`the
`vehicle and, therefore, there is a possibility that variations
`in the inclination of
`the vehicle body are not as
`large as
`variations in the output of
`the detection device due to the
`vehicle height
`and the like.
`‘
`if
`the leveling
`adjustment is made faithfully according to the output of the
`detection device,
`then there
`'
`a possibility that
`the
`illumination direction of
`the vehicle lamp can be corrected
`excessively when compared with the actual
`inclination of
`the
`vehicle body.
`
`

`
`The present invention was made in view of the foregoing
`problems accompanying the conventional device as discussed
`
`above. Therefore, it is an object of the present invention to
`provide a vehicle lamp illumination direction control device
`capable of controlling and properly adjusting the vehicle lamp
`illumination direction without correcting the same excessively
`while the vehicle is running along a rough road, whereby the
`visibility of the driver of the vehicle can be enhanced while
`the controlled vehicle lamp illumination direction can never
`dazzle the driver of an oncoming vehicle, so that the safety of
`the vehicle driving can be assured.
`
`according to the
`In attaining the above object,
`invention,
`in view of the fact that the posture change of the
`vehicle in the constant speed running condition of the vehicle
`or
`in the bad road running condition thereof
`is relatively
`smaller
`than the posture
`change of
`the vehicle in the
`acceleration or deceleration running condition of
`thereof,
`there is provided a vehicle lamp illumination direction control
`device for changing the direction of the illumination light of
`a lamp according to the vertical inclination of a vehicle in
`the advancing direction thereof, the control device comprising:
`a vehicle posture detection device for detecting the
`posture of
`the vehicle during the stationary and/or moving
`condition thereof;
`
`an acceleration or deceleration running condition
`judging device for
`judging whether
`the vehicle is in the
`acceleration running condition or in the deceleration running
`condition or not;
`
`

`
`light of the lamp in a given direction,
`
`in accordance with a
`
`signal received from the vehicle posture detection device,
`
`wherein, when it is judged by the acceleration or deceleration
`
`running condition judging device that
`
`the vehicle is in the
`
`acceleration running condition or in the deceleration running
`
`condition,
`
`the direction of the lamp can be controlled by the
`
`signal
`
`transmitted from the correction calculating device to
`
`the drive device, and, when it is judged by the acceleration or
`
`deceleration running condition judging device that the vehicle
`
`is not
`
`in the acceleration running condition or
`
`in the
`
`deceleration running condition,
`
`the drive device can fix the
`
`the lamp in a given
`the illumination light of
`direction of
`direction or can limit the allowable range of the direction of
`
`the illumination light, or
`device can be slowed down.
`
`the response speed of
`
`the drive
`
`According to the invention, when it is found that the
`
`vehicle is not
`condition,
`the
`
`in the acceleration or deceleration running
`control device
`controls
`the
`illumination
`
`direction of
`the
`lamp
`by
`fixing the direction of
`the
`illumination light of
`the lamp in a given direction, or by
`limiting the direction of the illumination light to a limited
`
`range, or by slowing down the response speed of
`
`the drive
`
`device,
`
`thereby being able
`
`to prevent
`
`the
`
`illumination
`
`direction of the lamp from being changed excessively and thus
`prevent
`the illumination direction of
`the lamp‘
`fronl being
`corrected excessively in the bad road running condition of the
`vehicle.
`
`In the accompanying drawings:
`
`Fig.
`
`1 is a block diagram of the structure of a vehicle
`
`lamp illumination direction control device according to the
`invention;
`
`2 is a schematic view of a vehicle for explanation
`Fig.
`of height detection device;
`
`

`
`Fig.
`
`3 is an explanatory view of a correction control
`
`on the illumination direction of a vehicle lamp;
`
`Fig.
`
`4 is a graphical representation of an example of
`
`the change with time of a detect
`
`level detected by vehicle
`
`speed detection device;
`
`Fig.
`
`5 is a flow chart of a judging processing on the
`
`acceleration or deceleration running condition of the vehicle;
`
`Fig.
`
`6 is a graphical representation of an example of
`
`a detect level detected by a height sensor;
`
`Fig.
`
`7 is an explanatory view of a method for judging
`
`the bad road running condition of the vehicle by combined use
`
`of a height sensor and an angular velocity sensor;
`
`Fig.
`
`8 is a schematic view of an example of a method
`
`for changing the illumination direction of the lamp by driving
`and controlling the entire lamp;
`
`Fig.
`9 is an explanatory view of a method for limiting
`the allowable range of the illumination angle of the lamp when
`it
`is judged that
`the vehicle is in the acceleration or
`
`deceleration running condition;
`
`Fig. 10 is an explanatory view of a method for limiting
`the allowable range of the illumination angle of the lamp to
`thereby prohibit the occurrence of an upwardly directed light
`when it is judged that the vehicle is in the acceleration or
`
`deceleration running condition;
`
`Fig. 11 is an explanatory view of a method for slowing
`down the response speed of drive device when it is judged that
`the vehicle is in the acceleration or deceleration running
`condition;
`
`Fig. 12 is an explanatory view of a method for changing
`the illumination direction of
`a
`reflector by driving or
`controlling the reflector;
`
`Fig. 13 is an explanatory view of a method for changing
`the illumination direction of a lens by driving or controlling
`the lens; and,
`
`

`
`Fig. 14 is an explanatory view of a method for changing
`the illumination direction of a shade by driving or controlling
`the shade.
`
`Now, description will be given below of an embodiment
`a vehicle lamp
`illumination direction control device
`of
`according to the invention with reference to the accompanying
`drawings.
`
`the present
`the basic structure of
`shows
`1
`Fig.
`invention,
`in which an illumination direction control device 1
`includes a vehicle posture detection device 2, a control device
`3
`(which is composed of correction calculating device 3a and
`acceleration or deceleration running condition judging device
`3b), a drive device 4
`(which is composed of a drive control
`device 4a and a drive mechanism 4b), and a lamp 5.
`is used to
`The vehicle posture detection device 2
`the posture of a vehicle while it is standing still
`detect
`and/or moving
`(including the vertical
`inclination of
`the
`vehicle while it is running). For example, when there is used
`a vehicle height detection device 6 which detects the height of
`the vehicle body according to the uneven surface of the road,
`as shown in Fig. 2,
`there are available a method for measuring
`a distance L between the vehicle height detection device 6 and
`the road surface G by use of detect waves such as ultrasonic
`waves,
`laser beams or
`the like,
`and a method in which the
`vehicle height detection device 6 detects the amount x of the
`expansion and contraction of a suspension 5. These two methods
`are both advantageous in that the existing facilities in the
`vehicle can be used.
`
`The outputs of the vehicle posture detection device 2
`are transmitted to the correction calculating device 3a and
`
`

`
`and these outputs are used as control signals to be applied to
`the drive device 4
`and are then used as
`instructions for
`
`correcting the illumination condition of the lamp 5.
`
`the correction calculating device 3a is
`In particular,
`structured in the following manner: that is, in accordance with
`a detect signal from the vehicle posture detection device 2, it
`transmits a control signal to the drive device 4 so that the
`illumination direction of the lamp 5 can be always kept
`in a
`given direction.
`For example, as shown in Fig. 3, when the
`vehicle body rises in the front portion thereof with respect to
`a light distribution pattern PN (shown by a solid line in Fig.
`3) which is set using a horizontal line H-H or a vertical line
`V-V as a reference line, the illumination direction of the lamp
`5 varies upward with respect
`to the horizontal
`line H-H and
`thus
`the light distribution pattern varies upward like a
`pattern PU (shown by a one-dot chained line in Fig. 3).
`In
`this case,
`the correction calculating device 3a transmits to
`the drive
`control device
`4a
`a
`signal which
`causes
`the
`illumination direction of the lamp 5 to vary downward as well
`as the light distribution pattern thereof to vary downward and
`coincide with the light distribution patter PN as shown by an
`arrow A in Fig. 3. Also, contrary to this, when the vehicle
`
`also varies downward like a pattern PD (shown by a two—dot
`chained line in Fig.
`3).
`In this case,
`the correction
`calculating device 3a transmits to the drive control device 4a
`a signal which causes the illumination direction of the lamp 5
`to vary upward as well as
`the light distribution pattern
`thereof to vary upward and coincide with the light distribution
`pattern PN as shown by an arrow B in Fig. 3.
`Now, the acceleration or deceleration running condition
`judging device 3b is used to judge whether
`the vehicle is
`
`

`
`increasing its speed or decreasing its speed. When the judging
`device 3b judges that
`the vehicle is in an acceleration or
`deceleration running condition,
`in accordance with a control
`signal transmitted from the correction calculating device 3a to
`the drive control device 4a,
`the acceleration or deceleration
`
`transmits a control signal to the drive device 4, so that the
`illumination direction of
`the lamp 5
`can be
`fixed in a
`predetermined direction or limited to a given range, or the
`response speed of
`the drive mechanism 4b for varying the
`illumination direction of the lamp 5 is slowed down to thereby
`be able to control the illumination direction of the lamp 5 in
`such
`a manner
`that
`'
`'
`.
`basic
`'
`'
`'
`information used to
`in the
`acceleration or deceleration running condition or not, besides
`the information that is given by the vehicle posture detection
`device
`2,
`as
`'
`'
`1,
`'
`also available
`information which can be obtained by providing acceleration or
`deceleration instruction detection device 8 used to detect an
`acceleration or deceleration
`instruction or
`information
`relating to the present instruction according to the amount of
`pressing—down of a gas pedal, variations in the opening angle
`of a throttle valve or the like,
`
`

`
`judging
`A judging method for
`condition judging device 3b.
`whether
`the vehicle is in the acceleration or deceleration
`
`running condition or not will be described later below.
`
`The drive control device 4a is used to receive signals
`
`from the correction calculating device 3a and acceleration or
`
`deceleration running condition judging device 3b and allow the
`
`drive mechanism 4b to control or
`
`change
`
`the illumination
`
`direction of
`
`the lamp 5.
`
`The control or change of
`
`the
`
`illumination direction of
`
`the lamp 5
`
`can be achieved by
`
`inclining the entire lamp 5 or by moving part of the components
`
`of the lamp 5 such as a shade or the like, while the details of
`
`these controlling or changing methods will be given later.
`
`At first,
`
`the judging method in the acceleration or
`
`deceleration running condition judging device
`
`3b will
`
`be
`
`described by classifying it into the following four methods:
`
`i)
`
`a method using the vehicle speed detection
`
`device;
`
`ii)
`
`a method using the acceleration or deceleration
`
`instruction detection device 8;
`
`a method using the engine revolution number
`
`detection device 9; and,
`
`iv)
`
`a. method using the vehicle posture detection
`device 2.
`
`Firstly, the method i) is a method which judges whether
`
`the vehicle is in the acceleration or deceleration running
`
`condition or not by detecting the running speed of the vehicle
`
`to calculate the change of
`
`the speed with time,
`
`that is, by
`
`calculating the acceleration of
`
`the vehicle.
`
`The present
`
`method i) is advantageous in that the vehicle speed detection
`
`device 7 is one of the existing facilities in the vehicle and
`use of the detect signal of the vehicle speed detection device
`
`7 facilitates the judgment on the acceleration or deceleration
`
`running condition of the vehicle.
`
`

`
`Pig. 4 shows an example of the change of the speed with
`in which the axis of abscissa expresses the time t and
`time,
`the axis of ordinate expresses the speed v (t) of the vehicle.
`In Fig. 4, a period designated by Ta expresses the acceleration
`period of the vehicle, a period designated by Tb expresses the
`deceleration period of the vehicle, a period designated by Tc
`expresses the constant
`speed period of
`the vehicle,
`and a
`period designated by Td expresses the bad road running period
`of the vehicle.
`
`Based on the speed v obtained from the vehicle speed
`detection device 7, if the time differential of the speed v or
`an acceleration dv (t)/dt is calculated,
`the acceleration is
`
`zero in the
`and the acceleration is given as
`period Tb,
`constant speed period or a small value in the bad road running
`period Td.
`Therefore, by comparing the acceleration or the
`absolute value thereof with a given reference value, it is
`possible to judge whether the vehicle is in the acceleration or
`deceleration running condition or not.
`
`Now, Fig. 5 is a flow chart which shows the flow of the
`acceleration or deceleration running condition judging process,
`that is, Fig.
`5 shows
`the procedure of the processing to be
`performed by the above-mentioned acceleration or deceleration
`running condition judging device 3b.
`
`is
`(t)
`the vehicle speed v
`in Step S1,
`At first,
`detected and, after then,
`in Step 52,
`the acceleration dv
`(t)/dt or the absolute value thereof is calculated. Next,
`in
`Step 53, it is checked whether the acceleration dv (t)/dt or
`the absolute value thereof
`is
`equal
`to or more
`than a
`reference value or not.
`If it is found that the acceleration
`dv
`(t)/dt or
`the absolute value thereof
`is less than the
`reference value,
`then the processing advances to Step S5.
`
`

`
`In Step S4, it is judged that the vehicle is in the
`
`acceleration or deceleration running condition and, after then,
`the processing goes back to Step 82. Also,
`in Step S5, it is
`judged that
`the vehicle is not
`in the acceleration or
`
`deceleration running condition and, after then,
`returns back to the first step 51.
`
`the processing
`
`As described above,
`
`the method i) is a method which
`
`the vehicle and,
`the variations in the speed of
`monitors
`therefore, when an instruction for acceleration or deceleration
`
`of
`
`the vehicle given by
`
`a driver
`
`cannot
`
`be
`
`reflected
`
`instantaneously on the speed of the vehicle,
`
`there is a fear
`
`that a time delay can occur in the judgment of the acceleration
`
`In this case, as shown in the method ii), as
`or deceleration.
`the information relating to the acceleration or deceleration
`
`instruction of
`
`the vehicle,
`
`there can be used the detect
`
`information relating to the variations
`
`in the amount of
`
`the accelerator pedal or relating to the
`pressing-down of
`variations in the amount of opening of the throttle valve.
`
`the variations in the accelerator pedal
`In particular,
`pressing-down amount or the variations in the throttle valve
`
`opening amount is large when the vehicle is in the acceleration
`
`is hereinafter
`(which
`or deceleration running condition
`referred to as acceleration or deceleration time), while it is
`small when the vehicle is running at a constant speed or along
`a bad road. Therefore, by detecting a difference between the
`variations, it is possible to judge whether the vehicle is in
`the acceleration or deceleration running condition or not.
`In
`other words,
`in Fig.
`5, Step 51 may be
`replaced by the
`detection of the accelerator pedal pressing-down amount or the
`throttle valve opening amount,
`the variations in these amounts
`
`the thus
`then,
`may be calculated in Step 52 and, after
`calculated value may be compared'with the given reference value
`in Step 53, whereby the following processing (that
`is,
`the
`processing to be performed after then) can be decided.
`
`

`
`In another method, attention is paid to variations in
`the state of the drive source of the vehicle, that is, as shown
`in above-mentioned method iii), by detecting variations in the
`number of
`revolutions of
`the engine,
`the judgment on the
`acceleration or deceleration running condition can be achieved.
`
`that the variations in the
`That is, due to the fact
`engine
`of
`number
`revolutions
`of
`the
`are
`large
`in the
`acceleration or deceleration running condition of the vehicle,
`whereas the variations are small in the constant speed running
`condition or in the bad road running condition, by detecting a
`difference between the variations,
`it is possible to judge
`whether
`the vehicle is in the acceleration or deceleration
`running condition or not.
`In this case,
`in Fig. 5,
`the number
`of revolutions of
`the engine may be detected in Step 51,
`a
`variation in the number of revolutions of
`the engine may be
`calculated in Step S2 and, after then,
`the thus calculated
`
`53, whereby the following processing can be decided.
`
`As described above, based on the respective pieces of
`information that are obtained by calculating the amounts of
`variations with
`time
`of
`the vehicle
`speed,
`the
`speed
`instruction given by the driver, and the state of
`the drive
`source of
`the vehicle, or based on the information that
`is
`obtained by combining them with each other,
`the variations in
`the acceleration or deceleration condition of the vehicle can
`be detected.
`
`The remaining method iv) is a method which can judge
`the acceleration or deceleration running condition of
`the
`vehicle based on the information that
`is obtained by the
`vehicle posture detection device 2. Generally, as a device for
`detecting variations in the vibration of
`a mechanism for
`absorbing the vibration that
`is given to the wheels of
`the
`vehicle from the surface of a road or for detecting the height
`of
`the axle of
`the vehicle,
`there is used height detection
`
`

`
`In the present
`device such as a height sensor or the like.
`method, based on the information that
`is obtained from the
`
`height detection device, the time differential of the detected
`
`level or the absolute value thereof is calculated and, after
`then, by comparing the resultant value with a given reference
`value, it is possible to judge whether the vehicle is in the
`
`acceleration or deceleration running condition or not.
`
`several positions of the vehicle, for example, in the front and
`
`rear portions thereof and/or right and left portions thereof
`and the inclination angle in the pitching direction of
`the
`vehicle (so called pitch angle) is detected in accordance with
`the detect
`information that
`is detected by these height
`detection device, then the running condition of the vehicle can
`be confirmed to a certain degree.
`However, actually,
`there
`exists
`a
`state in which
`it
`is difficult
`to tell
`the
`
`acceleration or deceleration running condition of the vehicle
`from the bad road running condition only by means of
`such
`height detection device.
`
`Now, Fig. 6 shows an example of the level variations in
`the detect signal that is output from a height sensor attached
`to the vehicle.
`In Fig. 6,
`the axis of abscissa expresses the
`time t and the axis of ordinate expresses the level V of the
`detect signal.
`
`In Fig. 6, a period designated by T1 expresses a period
`in which the vehicle is in an acceleration or deceleration
`running condition, a period designated by T2 expresses a period
`in which the vehicle is in a constant speed running condition,
`and a period designated by T3 expresses a period in which the
`vehicle is in a bad road running condition. Fig.
`6 tells that
`the width of the amplitude variations in the output signal of
`the height sensor is large in the periods T1 and T3.
`
`in order to judge whether the vehicle is in
`That is,
`the acceleration or deceleration running condition or in the
`
`

`
`bad road running condition,
`
`it is necessary to recognize a
`
`difference between the detected level variations in the period
`
`T1 and T3.
`
`For example, attention is paid to a difference
`
`between the degrees of the variations in the detected levels
`
`and the judgment is made in accordance with the fact that the
`
`amplitude variations in the detected levels in the period T3
`are heavier.
`However,
`as
`a method which can enhance the
`
`accuracy of
`
`the judgment,
`
`there can be pointed out a method
`
`which detects the variations in the detected levels by using
`the vehicle height detection device and angular velocity
`detection device in combination.
`
`7 shows a method which carries out a judgment
`Now, Fig.
`on the acceleration or deceleration running condition of the
`vehicle by using a height sensor and an angular velocity sensor
`in combination.
`In Fig. 7, a graphical representation shown in
`the upper stage thereof represents variations with time in the
`
`the
`(which is expressed as dB/dt) of
`time difference amount
`pitch angle of the vehicle calculated from the detect level V
`
`of the height sensor, whereas a graphical representation in the
`lower stage thereof represents variations with time in the
`
`(which is expressed as m) of the angular velocity
`output level
`sensor which is installed at a position above the suspension of
`the vehicle to detect
`the pitch angle. Here,
`in Fig. 7,
`a
`period Tl expresses a period in which the vehicle is running at
`a constant speed along a comparatively even road, a period T2
`
`expresses a period in which the vehicle is running in an
`acceleration or deceleration condition,
`and
`a period T3
`expresses a period in which the vehicle is running on a bad
`road, respectively.
`
`in the period T2,
`7,
`from Fig.
`seen
`can be
`As
`variations in d6/dt and u are found when the vehicle is running
`in
`the
`acceleration or deceleration condition, whereas
`variations in d6/dt and m are small
`in the period T1;
`in the
`period T3,
`the vibration component of dB/dt is large, whereas
`
`

`
`large variations are not found in w; and, therefore, it can be
`
`found that d6/dt and
`
`have no correlation between them or the
`
`relation between them is low.
`
`The reason for
`
`this is as
`
`follows: since the vibration of the suspension is detected by
`the height sensor in the bad road running condition of
`the
`
`vehicle, d6/dt calculated from the output of the height sensor
`is also affected by the influence of
`the thus detected
`
`vibration, whereas, because the influence of the vibration on
`
`the load portion of the suspension situated above the spring is
`absorbed by the expansion and contraction of the suspension,
`the present
`load portion is not
`inclined so greatly in the
`pitching direction and,
`therefore,
`the vibration component
`relating to the load portion of the suspension situated below
`
`reflected greatly’ on the output of
`the spring is not
`angular velocity sensor for detection of the pitch angle.
`In this manner, when there is found a correlative
`
`the
`
`the
`it can be judged that
`,
`variation between d6/dt and w
`vehicle
`is
`in the acceleration or deceleration running
`condition.
`In the other cases,
`that is, when de/dt and u are
`
`in variations, or when no correlation or only a small
`small
`correlation is found, it can be judged that
`the vehicle is
`
`running at a constant speed or along a bad road.
`
`(in
`the angular velocity sensor
`the number of
`Here,
`included in the vehicle posture detection device 2) is
`Fig. 1,
`not
`limited to one but, of course,
`a plurality of angular
`velocity sensors may be used,
`that is, it is also possible to
`obtain the information that
`is necessary for
`the angular
`velocity calculation based on
`the information from these
`
`angular velocity sensors.
`
`the
`to
`according
`above,
`been described
`has
`As
`respective methods, it is possible to judge whether the vehicle
`is running in the acceleration condition or in the deceleration
`
`condition.
`manners,
`
`these methods can be applied in various
`Also,
`for example,
`the respective methods
`can be used
`
`

`
`individually, or some of them may be combined together for the
`enhanced accuracy of the judgment.
`
`Next, description will be given below of the control of
`the direction of
`the illumination light of
`the lamp 5
`to be
`made by the drive device 4.
`
`simplest method for changing the illumination
`The
`the lamp 5 in a vertical plane is a method which
`pattern of
`changes the illumination angle of the lamp 5 with respect to a
`horizontal plane by rotating the entire lamp 5 about the rotary
`shaft thereof.
`For example,
`the right and left side surfaces
`of the lamp 5 are supported in a freely rotatable manner and
`the rotary shaft of the lamp 5 is rotated directly by a drive
`source such as a motor or the like, or,
`there is available a
`drive mechanism in which a member fixed to the lamp 5 or formed
`integrally with the lamp 5 is rotated by the drive device 4.
`As an example of such lamp,
`there is pointed out a lamp of a
`type that it employs a mechanism in which the rotational force
`of the motor is used as the rotational force of the lamp by a
`transmission nechanism using a worm and a worm wheel
`(for
`example, see Japanese Patent Publication No. Sho. 63—l66672).
`If it is judged by the acceleration or deceleration
`running condition judging device 3b that the vehicle is in the
`acceleration running condition or in the deceleration running
`condition,
`then the drive control device 4a rotates the entire
`lamp 5 within a vertical plane so that the lamp 5 can provide
`an
`illumination
`angle
`as
`specified
`by
`the
`correction
`calculating device 3a.
`
`acceleration or
`the
`by
`judged
`is
`it
`if
`Also,
`deceleration running condition judging device 3b
`that
`the
`vehicle is not
`in the acceleration or deceleration running
`condition,
`then the illumination angle of
`the lamp 5 can be
`controlled by one of
`the following methods when the drive
`control device 4a receives an instruction from the acceleration
`or deceleration running condition judging device 3b:
`
`

`
`1)
`2)
`
`3)
`
`a method for fixing the illumination angle;
`a vmethod
`for
`limiting
`the
`range
`of
`
`illumination angle or
`
`forbidding part of
`
`the
`
`the
`
`range of the illumination angle; and,
`
`a method for changing the response speed or
`control speed of an actuator.
`
`the method 1), which is the simplest in the
`At first,
`above-mentioned three methods, is a method which always holds
`the illumination angle of the lamp 5 at a constant angle when
`judging whether
`the vehicle
`is
`in the acceleration or
`deceleration running condition or not.
`That
`is, when the
`vehicle is not
`in the acceleration or deceleration running
`condition,
`in order to prevent
`the illumination light of the
`lamp 5 from being directed too upwardly, the lamp 5 may be held
`in such a condition that the illumination direction of the lamp
`5 can be directed a little downwardly.
`The then downwardly directed angle of illumination may
`be set for a value irrelevant to an illumination angle before
`it is judged that the vehicle is not
`in the acceleration or
`deceleration running
`condition,
`or may
`be
`set
`at
`an
`illumination angle just prior to the present
`judgment or an
`angle obtained by correcting the present
`illumination angle
`(for example, adjusting the present illumination angle a little
`downwardly), or, may be set at an average illumination angle
`prior
`to the pre