USOO7307395B2
`
`(12-) United States Patent
`US 7,307,395 B2
`(10) Patent N0.:
`Bouamra et al.
`(45) Date of Patent:
`Dec. 11, 2007
`
`(54) SAFETY DEVICE FOR A SLIDING PANEL
`DRIVEN BY AN ELECTRICAL MOTOR AND
`METHOD FOR IMPLEMENTING SUCH A
`DEVICE
`
`(56)
`
`References Cited
`
`U. S. PATENT DOCUMENTS
`
`5,051,672 A
`
`9/1991 Yaguchi
`
`(75)
`
`Inventors: Mohamed Bouamra, Strasbourg (FR);
`,
`.
`.
`.
`Jesus Zaldua, Hondarnb1a - G1puzkoa
`'
`.
`.-
`_
`,
`(ESL Jam? Vl‘d‘ld's
`Zarautl - Glpuzkoa (ES); Jesus
`
`Irlondo, Zarautz - Glpuzkoa (AS)
`.
`.
`~
`:Tllt Thl
`Hld
`S.A.
`73 A
`’
`SSlgnee Lfixefgbo? 1&3?“
`)
`(
`0 mgs
`rg
`( * ) Notice:
`Subject to any disclaimer. the term of this
`patent is extended or adjusted under 35
`U.S.C. 1540,) bv 888 days.
`(21) Appl. N0.: 10/742,777
`
`(22)
`
`(65)
`
`F11ed:
`
`Dec. 23, 2003
`
`Prior Publication Data
`US 2004/0138843 A1
`Jul. 15, 2004
`
`4/1995 Takéda et. 31'
`5’404’673 A
`4/1995 Seklguchl et a1.
`5,410,226 A
`7/1995 Waggamon
`5,428,923 A
`6/1998 Ishihara et a1.
`5,774,046 A
`9/1998 Tsuge et a1.
`5,801,347 A
`3/1999 Tsuge et :11
`5,880,421 A
`8/1999 Tanaka et al.
`5 932 931 A
`”
`12/2000 Castellon
`6,163,080 A
`11/2001 Kashiwazaki et a1.
`6,316,846 B1
`2004/0257235 A1* 12/2004 Right et a1.
`................. 340/628
`
`DE
`
`FOREIGN PATENT DOCUMENTS
`38 09 957
`10/1989
`
`(Continued)
`
`Primary ExamineriKaren Masih
`(74) Attorney, Agent, or Firmisughrue Mion, PLLC
`
`Related US. Application Data
`(62) Division of application No. 09/460,969, filed on Dec.
`15, 1999, now Pat. No. 6,772,559.
`
`(30)
`
`Foreign Application Priority Data
`
`Dec. 15, 1998
`
`(EP)
`
`.................................. 98123825
`
`(51)
`
`Int. Cl.
`(2006.01)
`G05B 5/00
`(52) US, Cl,
`...................... 318/445; 318/443; 318/444;
`318/449; 318/466; 318/469
`(58) Field of Classification Search ................ 318/445,
`318/443, 444, 449, 466, 467, 468, 469, 280;
`340/628
`See application file for complete search history.
`
`(57)
`
`ABSTRACT
`
`The invention concerns a sequential safety system associ—
`ated with a moving closing panel driven so as to slide by an
`electric motor (6), this safety system including means (20)
`exploiting the signal originating from an optical fiber to stop
`and reverse the direction of movement of said moving panel
`in the event of a change in the signal, as well as additional
`safety means allowing the end-of—travel positions of the
`moving panel to be determined without ambiguity via the
`joint exploitation of the results derived from measuring the
`frequency of the pulses caused by the rotation of the electric
`m010r(6) driving Said moving panel, as well as data origi-
`name from the Optlcal fiber.
`
`40 Claims, 11 Drawing Sheets
`
`
`
`UUSI, LLC
`
`Exhibit 2024
`
`WEBASTO ROOF
`
`SYSTEMS, INC.
`
`Petitioner
`
`v.
`
`UUSI, LLC
`Patent Owner
`
`Case:
`
`|PR2014-00650
`
`Patent: 7,579,802
`
`1/24
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`

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`US 7,307,395 B2
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`FOREIGN PATENT DOCUMENTS
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`DE
`3?
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`D]:
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`
`39 11 493
`2° 12 233
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`40 30 904
`43 31 781
`4— 23 104
`
`10/1990
`1111331
`3/1995
`3/1995
`1/1996
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`DE
`EP
`EP
`GB
`
`196 23 420
`197 24 952
`345 914
`419 267
`< < 7
`2 12“ “7“
`
`12/1997
`12/1997
`“1989
`9/1990
`3/1984
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`* cited by examiner
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`UUSI, LLC
`UUSI, LLC
`Exhibit 2024
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`2/24
`2/24
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`US. Patent
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`Dec. 11, 2007
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`Sheet 1 0f 11
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`US 7,307,395 B2
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`UUSI, LLC
`UUSI, LLC
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`US. Patent
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`Sheet 2 0f 11
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`UUSI, LLC
`UUSI, LLC
`Exhibit 2024
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`US. Patent
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`Sheet 3 0f 11
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`Fig.7
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`‘9}
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`32
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`28
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`28
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`32
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`Hg.8
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`Output signal
`level of sensor
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`Hg.9
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`Output signal
`level of sensor
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`Threshold
`level
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`of sensor
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`Output level
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`Threshold
`level
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`Begining of the
`period in which the
`motor is stopped
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`Time
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`Output level
`of sensor
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`Begining of the
`Time
`period in which the
`motor is stopped
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`UUSI, LLC
`UUSI, LLC
`Exhibit 2024
`Exhibit 2024
`5/24
`5/24
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`US. Patent
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`Sheet 4 0f 11
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`Hg. 10
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`Output signal
`level of sensor
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`Hg. 1 1
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`Output signal
`level of sensor
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`Threshold
`level
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`Outpul level
`of sensor
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`_______ Threshold
`level
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`Output level
`ol sensor
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`Beglnlng of the
`period in which the
`motor is stopped
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`Time
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`Begining of the
`period in which the
`motor is stopped
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`Time
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`Flg. 1 2
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`UUSI, LLC
`UUSI, LLC
`Exhibit 2024
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`US. Patent
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`UUSI, LLC
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`UUSI, LLC
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`UUSI, LLC
`UUUUUUUU
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`UUSI, LLC
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`UUSI, LLC
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`US. Patent
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`UUSI, LLC
`UUSI, LLC
`Exhibit 2024
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`
`
`This is a divisional of application Ser, No. 09/460,969
`filed Dec. 15, 1999, the disclosure of which is incorporated
`herein by reference.
`'lhe present invention concerns a method called a sequen-
`tial method for controlling a sliding moving panel driven by
`an electric motor, wherein the signal originating from an
`optical fibre pressure sensor is exploited in a sequential
`manner to stop and reverse the operating direction of the
`driving motor in the event of a variation in said signal, and
`wherein the frequency measurement of the pulses generated
`by an encoding device is exploited to perform pre-detection
`of an obstacle and to determine the end of travel positions of
`the moving panel.
`The invention also concerns a safety device for such a
`moving panel including means for detecting the presence of
`a foreign body braking said moving panel’s movement and
`preventing it from closing completely.
`The invention also concerns an optical fibre force sensor
`able to be used in particular in safety devices of the
`aforementioned type,
`Finally, the object of the invention is to provide a method
`for calibrating the aforementioned direct and indirect detec-
`ion means which allows the reliability of the operation of
`the sensor to be increased.
`Automobile vehicles are increasingly fitted with electric
`windows, i.e. systems wherein the windows are driven so as
`o slide in the opening direction or the closing direction by
`an electric motor whose operation is controlled by the driver
`of the vehicle by means of a manual switch. Such systems
`iave allowed substantial progress to be made as regards
`automobile safety, insofar as the driver can easily open or
`close the windows while continuing to pay attention to trafiic
`conditions and to driving the vehicle. These systems have,
`lowever, significant problems as to reliability which are
`often linked to the appearance of current peaks when the
`motor driving the window is stopped too abruptly. It
`is
`(nown that any obstacle blocking the movement of the
`window generates current peaks in the motor which are
`generally damaging, particularly for certain components,
`such as the control relays or the switching transistors. Such
`oeaks can appear, for example, when the driver continues to
`activate the switch which controls the operation of the
`driving motor when the window has already reached the
`closed position in which it is pressed against the door frame.
`Current peaks can also appear when a foreign body, for ,
`example an arm, is resting on the edge of the window and
`prevents the latter from moving upwards.
`In order to overcome the aforementioned difiiculties, a
`known solution consists in measuring the maximum level of
`the supply current provided to the driving motor, and block-
`ing said current above a predetermined threshold. This
`measurement is generally performed across the terminals of
`a switching transistor whose resistance varies from one
`component to another and remains dependent upon the
`temperature. Other methods use precision resistors (current
`measurements) or Hall effect sensors (magnetic field mea-
`surements), but the cost price of such components is high.
`Another control method, which is less expensive and
`more efficient, consists in detecting the pulses caused by the
`switching of the driving motor brushes. These pulses are
`superposed with the direct consumption current of the
`motor. and their frequency is proportional to the speed of the
`
`10
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`20
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`Lu v.
`
`40
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`55
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`60
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`US 7,307,395 B2
`
`1
`SAFETY DEVICE FOR A SLIDING PANEL
`DRIVEN BY AN ELECTRICAL VIOTOR AND
`METHOD FOR IMPLENIENTING SUCH A
`DEVICE
`
`2
`rotor. A technique of this type is described in US. Pat. No.
`4,870,333 in the name of the Sidosha Denki Kogyo com—
`pany which proposes a method for controlling electric
`windows for automobile vehicles wherein the number of
`pulses generated by the operation of the electric motor
`driving the window is stored in a counter. When the number
`of pulses stored in the counter reaches a maximum prede-
`temiined value, the control device which operates the sys-
`tem concludes that the window has reached the fully open
`position and causes the driving motor to stop. Conversely,
`when the window moves up, the number of pulses stored in
`the counter is reduced by one unit per revolution of the
`driving motor. When this number becomes equal to zero, the
`system concludes that the window has reached the closed
`position in which it presses against the door frame, and again
`stops the driving motor.
`The main drawback of the above system is that the speed
`at which the window rises is not constant and depends on
`numerous parameters such as the drive torque of the motor,
`the friction between the window and the door frame, the
`
`
`speed and trajectory of the vehicle, etc. Consequently, the
`
`position of the window cannot be calculated with su icient
`
`accuracy for the moment at which the window is comfllctely
`closed to be determined exactly. With such a method, one
`can at most determine an end of travel zone in which one
`knows that
`the window is close to the door frame. The
`driving motor can, consequently, be stopped on the com-
`mand of the control device before the window is completely
`closed. Conversely, the window can continue to be supplied
`with current when the window is already completely closed,
`which generates ctu'rent peaks which are damaging to the
`motor and the electronic control circuit. On the other hand,
`nothing in the Sido sha patent is provided for detecting, prior
`to pinching, an overload which would form an obstacle to
`the progress of window. Finally, nothing is provided for
`detecting the presence of a foreign body such as a child’s
`hand, the thickness of which is equal to or less than the end
`of travel zone. Thus, during the automatic closing of moving
`panels, such as, in particular, an automobile vehicle window,
`one has to try to assure safety by preventing a foreign body
`such as, for example, an arm or a hand, being caught
`between said window and the door frame against which it
`has to be pressed. For this purpose,
`in the event
`that
`something is caught, a safety device stops the driving or
`reverses the direction of movement of the window. Among
`knoan safety devices, one solution consists in incorporating
`an electromagnetic wave guide, for example an optical fibre,
`inside the sealing gasket into which the window is guided.
`An emitter, for example a laser diode, injects a light signal
`at the end of the fibre. This signal propagates up to a
`receiver, for example a photodiode, placed at the other end
`of the fibre. In the event of an incident, the foreign body is
`driven by the window as it moves upwards towards the
`sealing gasket and exerts pres sure on the optical fibre. By the
`effect of the pressure, the optical fibre is deformed, which
`causes a local modification in its radius of curvature. This
`modification in the fibre’s radius of curvature causes sig-
`nificant losses, and consequently a drop in the amplitude of
`the optical signal picked up by the receiver. There results a
`drop in the amplitude of the electric signal transmitted by the
`receiver to a control circuit, which, in response to this drop,
`produces a stop or direction reversal signal for the motor
`driving the window.
`A safety device associated with the sliding window of the
`door of an automobile vehicle is known from German Patent
`No. DE 44 16 803. This device includes a magnet arranged
`on the shaft of the electric motor driving the window with
`
`UUSI, LLC
`UUSI, LLC
`Exhibit 2024
`Exhibit 2024
`14/24
`14/24
`
`

`

`US 7,307,395 B2
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`10
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`3
`which is associated a Hall effect sensor. As a function of the
`signals transmitted by the Hall effect sensor, a microproces—
`sor can determine that the window has reached its corn-
`pletely closed position. The microprocessor can also detect
`a reduction in the speed at which the window moves
`upwards due to the efi'ect of the presence of a foreign body,
`and can command the reversal of the direction of movement
`of said window to avoid anything being caught therein. In
`addition to this indirect detection device, the safety device
`includes a direct detection device including a pressure
`sensor arranged in the door frame.
`The main drawback of the above safety device lies in the
`fact that the indirect detection means continue to be used as
`obstacle detection means even when the window comes in
`proximity to its completely closed position. It has already
`been stated that the speed at which the window moves
`upwards is not constant and that it depends on numerous
`parameters. Thus, if because of measuring inaccuracies, the
`microprocessor does not indicate that the window is closed
`while the latter is in fact closed, said microprocessor will
`interpret this situation as a situation in which something is
`caught, and will command the driving motor to stop and
`reverse its working direction. It becomes impossible at this
`moment to close the window.
`The safety devices of the type described hereinbefore
`which use optical fibre pressure sensors as obstacle detectors
`have ntmierous drawbacks both as regards their industrial
`manufacture and as regards their performance with the user.
`These safety devices must, in fact, be produced on a large
`scale to satisfy the demands of the market, such as the
`automobile market. This thus assumes a manufacturing
`method which is both simple and quick with inexpensive
`components and materials. The same is true for the test and
`calibration procedures which must be quick and which allow
`the direct and indirect detection means to keep their oper-
`ating features over time. As will be seen in the following
`description,
`it
`is difiicult,
`in such conditions,
`to obtain
`products with homogenous features.
`A first problem is linked to the fact that it is difiicult to be
`able to have available large quantities of low cost optical
`sources having features which have little scattering. This
`concerns in particular the power and transmission angle as
`well as the radiation spectrum of such sources.
`A second problem is linked to the fact that the optical fibre
`used in the sensor has to be fixed to the optical source either
`by means of specific connectors or more simply by bonding.
`This requires several operations for preparing the ends of the
`fibre (stripping off the coating, breaking or polishing),
`centring the fibre with respect to the optical source, and
`finally fixing by means of quick setting resins. Large scale s
`manufacture necessarily involves significant dispersion of
`the power injection output in the fibre, which affects the
`performance of the sensor.
`As described hereinbefore, optical fibre sensors mostly
`work on the principle of losses induced by the variation in
`the radius of curvature of said fibre by the eifect of pressure.
`The setting in place of the fibre and preparation of the
`sensitive part of the sensor thus necessarily introduce dis—
`persion in the stresses in the optical fibre, which leads to
`dispersion in the performance of the sensors.
`It can also be noted that the performance of the sensors
`greatly depends on the conditions in which they are used,
`and their environment. This is the case, for example, of
`automobile applications where the sensors have to operate
`within ambient temperature ranges comprised between —400
`C. and +85° C. It is clear that,
`in such conditions,
`the
`features of certain components such as the optical source
`
`
`
`4
`cannot remain constant (emission power and spectral field).
`The same is true for the power injection output in the fibre
`which greatly depends on the thermal properties of the
`materials used for the source-fibre connection.
`The problem is all the more significant as regards the
`sensitive part of the sensor. Assuming that the optical fibre
`is not itself sensitive to temperature variations, the materials
`which are used as support and sheath. generally polymers,
`can undergo thermal stress, which results in pressure varia—
`tions applied to the fibre. These effects, to which is added the
`intrinsic sensitivity of the optical fibre to the temperature,
`can cause variations of more than 80% in the output signal.
`Finally, in addition to the problems linked to the condi-
`tions ofuse of the sensor, there are the inevitable variations
`in the features of the latter caused by normal wear of the
`materials and components.
`The list of the aforementioned problems shows the difii-
`culties which have to be overcome in order to be able to
`manufacture on a large scale and at a low cost optical fibre
`pressure sensors which can be used as obstacle detectors.
`Sensitivity to certain disturbances as well as wear phenom—
`ena mean that the original calibration cannot be kept. This
`results in problems of reliability and even, in certain cases,
`non operation of the safety devices using such sensors.
`The object of the present invention is to overcome the
`aforementioned problems and drawbacks by providing a
`reliable safety device for driving and closing sliding panels
`electrically powered.
`The invention thus concerns a sequential control method
`for a moving panel which is driven so as to slide in a frame
`by an electric motor. including the steps of:
`detecting by first means the presence of a foreign body
`capable of preventing the complete closing of said
`moving panel by becoming caught between said panel
`and the frame inside which said panel slides;
`measuring by second means the frequency of the pulses
`caused by the rotation of the electric motor driving the
`moving panel;
`generating an alarm signal when the presence of the
`foreign body is detected:
`stopping,
`then reversing the working direction of the
`electric driving motor on reception of the alarm signal;
`and
`stopping the driving motor or reversing its working direc-
`tion when the frequency of the pulses becomes sub—
`stantially zero in the absence of the alarm signal.
`Thus, when the window is closed, one can deduce that in
`the absence of the alarm signal, the window abuts against the
`door frame and that any risk of accident has been avoided.
`Conversely, in the case of the alarm signal, the reversal of
`the working direction of the driving motor is immediately
`commanded, As a result of these features, the sequential
`detection method according to the invention simultaneously
`allows personal safety to be increased and the electrical and
`electronic parts to be protected elliciently against current
`peaks.
`According to another feature of the method of the inven-
`tion, the frequency of the pulses caused by the rotation of the
`electric motor driving the panel is measured, and said motor
`is stopped or the working direction thereof is reversed when
`the frequency of said pulses becomes less than a predeter-
`mined frequency threshold.
`According to another feature of the method, the presence
`of a foreign body capable of preventing the complete closing
`of the moving panel
`is detected using an optical fibre
`pressure sensor.
`
`UUSI, LLC
`UUSI, LLC
`Exhibit 2024
`Exhibit 2024
`15/24
`15/24
`
`Lu v.
`
`40
`
`60
`
`

`

`US 7,307,395 B2
`
`5
`According to another feature of the method, one deducts
`from the measurement ofthe number of pulses caused by the
`rotation of the electric driving motor an indication of the
`travel of the moving panel from a previously known refer-
`ence position, and one commands a speed deceleration ramp
`of the driving motor, when the moving panel reaches an
`end-of-travel zone.
`According to another feature of the method, when the
`moving panel reaches the end-of-travel zone, the means used
`to measure the frequency ofthe pulses caused by the rotation
`of the electric motor are no longer used for detecting the
`presence of an obstacle capable of preventing the complete
`closing of the moving panel, but are only used for deter—
`mining the position of said panel relative to the frame into
`which it slides.
`According to another feature of the method, the reference
`position is the last calculated position of the moving panel
`prior to the stopping of the driving motor.
`The measurement of the number of pulses caused by the
`rotation of the driving motor allows the travel of the moving
`panel to be calculated from a previously known reference
`
`
`position. Ln the case ofan automobile vehicle, because of the
`
`
`inertial
`forces due to jerks,
`the e ects of friction and
`slipping, the indirect determination of the position of the
`window has a certain error rate. This error rate is cumulative.
`Thus, after ten attempts at moving the window downwards
`and upwards, the cumulative space between the calculated
`position and the real position of said window is of the order
`of one to two centimeters. However,
`this error remains
`sufficiently reliable to allow an end—of—travel zone to be
`defined for the downward and upward movements of the
`window, a zone in which said window is in proximity to the
`door frame against which it has to be applied. The delay time
`due to the variation in current with respect to the rotational
`speed of the motor is advantageously used to limit current
`peaks and to protect the motor and its control unit efficiently.
`'llre invention also concerns a method for controlling a
`moving panel driven so as to slide by an electric motor,
`characterised in that it consists in measuring the frequency
`of the pulses caused by the rotation of the electric motor
`driving the moving panel, and in stopping or reversing the
`working direction of said motor when the frequency of such
`pulses becomes less than a predetermined frequency thresh—
`old.
`Since the frequency of the pulses is proportional to the
`rotational speed of the driving motor, it becomes possible to
`detect the presence of an obstacle braking the movement of
`the closing panel and preventing it from moving upwards.
`This is the case, for example, of the action of an arm placed
`on the edge of an automobile vehicle window. The com-
`parison of this measured speed with a reference speed thus
`allows pre-detection of an obstacle and, in certain cases,
`prevents such obstacle being caught. It also allows the
`current peaks which are particularly damaging, especially
`for the driving motor electronic control circuit, to be con-
`siderably reduced.
`The invention also concerns a safety device including
`means for detecting the presence of a foreign body braking
`the movement of a moving panel driven so as to slide by an
`electric motor and preventing it from closing, characterised
`in that said detection means are of the indirect type, based
`on the measurement of the frequency of the pulses caused by
`the rotation of the electric motor.
`According to another feature of the invention, the afore—
`mentioned indirect type of detection means are associated
`with second means for directly detecting the presence of a
`foreign body,
`these means including a pressure sensor
`
`10
`
`Lu v.
`
`40
`
`o
`
`60
`
`6
`formed by an optical fibre associated with means for trans-
`mitting and receiving optical signals propagating within said
`fibre.
`Another object of the present invention is to provide an
`optical fibre pressure sensor which can be used as an
`obstacle detector keeping its original calibration despite its
`sensitivity to physical disturbances such as the temperature
`and to the wear phenomena of the materials of which it is
`formed.
`The invention therefore also concerns a method for cali-
`brating an optical fibre pressure sensor used as an obstacle
`detector in a drive system for an electrically sliding moving
`panel, the sensor including an emitter supplied with electric
`power which injects a light signal into an optical fibre, the
`light signal propagating up to a receiver which transmits, in
`response to the light signal transmitted by the optical fibre,
`an electric signal to a control unit with a microcontroller
`and’or a microprocessor which analyses the data originating
`from said receiver and, in the event of an incident, allows the
`electric motor driving the moving panel to be stopped or the
`working direction thereof to be reversed, the method being
`characterised in that, during the periods in which it
`is
`observed that
`the motor driving the moving panel has
`stopped, the operating parameters of the pressure sensor are
`compared and corrected, taken in any environmental con-
`ditions, as a function of the same parameters of a standard
`sensor taken in known reference conditions stored in a non
`volatile memory which is accessible to the microcontroller
`and/or the microprocessor of the control Imit.
`As a result of these features, the pressure sensor calibra—
`tion method begins as soon as the stopping of the motor
`driving the moving panel is observed. Preferably, the oper—
`ating parameters of the sensor are measured and corrected
`repeatedly during the entire duration of the stopping time of
`said driving motor. During the motor operating periods, only
`the last corrections of the pressure sensor operating param-
`eters stored in the memory are taken into account. The
`performances of the pressure sensor can thus be kept, despite
`wear phenomena and the existence of physical disturbances
`to which the sensor is sensitive.
`According to a first implementation variant, the method of
`
`the invention includes the steps of:
`
`
`cutting o m for a short instant the emitter’s electric supply
`current as soon as it is observed that the motor driving
`the moving panel has stopped;
`measuring the offset level of the electric signal transmit—
`ted by he receiver, then resetting its value to zero;
`supplying the emitter again by means of a constant direct
`electric current A10; and
`measuring the output level VS of the receiver, and allo-
`cating it a coefficient k such that kVS:VR, where VR is
`a known reference level of a standard sensor taken in
`known reference conditions.
`According to a second implementation variant,
`method of the invention includes the steps of:
`supplying the emitter by means of a periodic rectangular
`current;
`measuring the high output level VS of the receiver as well
`as its variation AVS, and
`performing the operation VS (AV’S/A\7R):V"S and deter—
`mining the coefiicient C:VR—VS' so that
`
`the
`
`
`
`VS":VR, where VR and AVR are known reference va ues of
`a standard sensor taken in known reference conditions, the
`
`
`ratio AVS/AVR is the pressure sensor sensitivity correction
`
`
`
`
`
`coe icient, and C is the residual offset correction coe icient
`of said sensor.
`
`
`
`UUSI, LLC
`UUSI, LLC
`Exhibit 2024
`Exhibit 2024
`16/24
`16/24
`
`

`

`US 7,307,395 B2
`
`the
`
`7
`According to another altemative implementation,
`method of the invention includes the steps of:
`supplying the emitter by means of a periodic rectangular
`current;
`measuring the high output level VS of the receiver as well
`as its variation AVS;
`calculating the pressure applied as a function of the level
`of the measured signal by means of a polynomial
`equation of a degree greater than or equal to 1 and
`whose coefficients are initially determined during a first
`calibration; and
`periodically correcting these coefficients as a function of
`the measurement results in order to obtain a reliable
`pressure measurement.
`Yet another obj eet of the present invention is to provide a
`pressure sensor which is simple and inexpensive to manu-
`facture.
`The invention also concerns a method for calibrating
`means for indirectly detecting the presence ofa foreign body
`capable of preventing the complete closing of a moving
`panel driven so as to slide into a frame by an electric motor,
`these means allowing the detection of the electric pulses
`generated by the rotation of the motor and controlling the
`stopping, then the reversal of the working direction of saic
`motor when the frequency of the pulses becomes less than
`a threshold frequency, this method being characterised in
`
`that it includes the s eps of:
`
`
`
`measuring, for di erent positions of the moving pane
`relative to the frame in which said panel moves, the
`corresponding frequency of the pulses caused by the
`rotation of the motor to determine the instantaneous
`speed ofmovement of the panel in a given position; anc
`comparing, for each position of the moving panel, the
`frequency of the measured pulses to the frequency 0 ‘
`the same pulses during the preceding travel of saic
`moving panel so that, if there is a difference between
`said frequencies and this difference does not exceed a
`predetermined safety value, the threshold frequency is
`corrected so that it does not command the stopping anc
`reversal of the working direction of the motor.
`Other features and advantages of the present invention
`will appear more clearly upon reading the following descrip-
`tion of an implementation example of the method according
`to the invention, this example being given purely by way of
`non—limiting illustration in conjunction with the annexed
`drawings, in which:
`FIG. 1 shows a door of an automobile vehicle fitted with
`the security device according to the invention;
`FIG. 2 is a cross—section along the line II—II of FIG. 1;
`FIG. 3 is a similar View to that of FIG. 2 in which a
`foreign body, such as a linger caught between the window
`and door frame, is shown;
`FIG. 4 is a schematic diagram of the safety device
`according to the invention;
`FIG. 5 is a schematic diagram of an optical fibre pressure
`sensor operating in transmission mode;
`FIG. 6 is a schematic diagram of an optical fibre pressure
`sensor operating in reflection mode;
`FIG. 7 is a schematic diagram of the means for switching
`the stop-start states and for controlling the direction of
`rotation of the motor as well as the means for indirectly
`detecting the presence of a foreign body braking the move-
`ment of the automobile vehicle window;
`FIGS. 8 to 12 illustrate two autocalibrating methods of the
`safety system according to the invention;
`
`
`
`8
`FIGS. 13 to 16 are perspective views of various altema-
`tive embodiments of the pressure sensor according to the
`invention;
`FIG. 17 is a general perspective View of the electric
`driving motor associated with an optical encoding device;
`FIG. 18 is a perspective View ofthe electric driving motor
`and the optical encoding device shown in FIG. 17 in the
`disassociated state;
`FIG. 19 is a perspective View of the driving motor on the
`shaft of which is mounted an optical encoding disc associ-
`ated with an opto—coupling device;
`FIG. 20 is a larger scale detailed view ofthe encoding disc
`and the opto—coupling device shown in FIG. 19;
`FIG. 21 is a perspective View of a printed circuit on the
`bottom face of which is fixed the opto—coupling device;
`FIG. 22 is a perspective View showing the opening made
`in the case accommodating the motor shaft for the passage
`of the opto-coupling device; and
`FIG. 23 is a detailed view of the opening made in the case
`shown in FIG. 22.
`The present invention proceeds from the general inventive
`idea which consists in providing a sequential detection
`system in which the indirect detection means, based on
`measuring the frequency of the pulses caused by rotation of
`the electric driving motor, allow the electric and electronic
`elements to be elliciently protected from the current peaks
`which are particularly harmful to them, whereas the direct
`
`detection means, based on measuring the variation in a
`
`
`physical disturbance due to the e ect of the presence of a
`foreign body preventing a moving panel from closing com—
`pletely, allow personal safety to be increased considerably.
`The present invention will be described with reference to
`an electric window lifter device fitted to an automobile
`vehicle. It goes without saying however that the present
`invention applies to all
`types of electrically controlled
`mov