`Uebelein et al.
`
`(lo) Patent No.:
`(45) Date of Patent:
`
`US 6,236,176 B1
`May 22, 2001
`
`III 1111uuunmRumiu11iiniun
`
`(54) METHOD FOR ELECTRONIC CONTROL
`AND ADJUSTMENT OF THE MOVEMENT
`OF ELECTRICALLY ACTUATED UNITS
`
`(75)
`
`Inventors: Jörg Uebelein, Grub am Forst; Roland
`Kalb, Rossach; Jürgen Seeberger,
`Baunach, all of (DE)
`
`(73) Assignee: Brose Fahrzeugteile GmbH & Co.
`KG, Coburg, Coburg (DE)
`
`( *) Notice:
`
`Subject to any disclaimer, the term of this
`patent is extended or adjusted under 35
`U.S.C. 154(b) by 0 days.
`
`(21) Appl. No.:
`
`09/367,398
`
`(22) PCT Filed:
`
`Mar. 10, 1998
`
`(86) PCT No.:
`
`PCT /DE98/00757
`
`§ 371 Date:
`
`Aug. 12, 1999
`§ 102(e) Date: Aug. 12, 1999
`
`(87) PCT Pub. No.: WO98/40945
`
`PCT Pub. Date: Sep. 17, 1998
`Foreign Application Priority Data
`
`(30)
`
`Mar. 12, 1997
`
`(DE)
`
`Int. Cl.7
`(51)
`(52) U.S. Cl.
`
`(58) Field of Search
`
`HO2P 7/00
`318/287; 318/280; 318/434;
`318/461; 318/469
`318/287, 434,
`318/469, 461, 465
`
`(56)
`
`References Cited
`
`U.S. PATENT DOCUMENTS
`
`4,468,596
`4,571,884
`4,641,067 *
`4,686,598
`4,746,845 *
`5,170,108
`
`8/1984
`2/1986
`2/1987
`8/1987
`5/1988
`12/1992
`
`Kinzl et al.
`.......................... 318/287
`Hetmann et al.
`49/72
`........................ 318/287
`Iizawa et al.
`Herr ....................................... 361/31
`....................... 318/286
`Mizuta et al.
`Peterson et al.
`318/469
`
`5,268,623
`5,331,367
`5,334,876 *
`5,399,950
`5,410,229
`5,422,551
`5,483,135
`5,521,474
`5,530,329
`
`12/1993 Muller
`7/1994 Kawasaki et al .
`8/1994 Washeleski et al.
`3/1995 Lu et al.
`4/1995 Sebastian et al .
`6/1995 Takeda et al.
`1/1996 Parks
`5/1996 Hahn
`6/1996 Shigematsu et al.
`
`318/434
`354/412
`307/10.1
`318/565
`318/434
`318/265
`318/469
`318/285
`318/469
`
`(List continued on next page.)
`
`FOREIGN PATENT DOCUMENTS
`
`30 34 118
`33 01 071 Al
`33 46 366
`35 32 078
`35 14 223
`42 14 998
`43 16 898
`195 11 581
`44 11 300
`195 17 958
`
`3/1982 (DE) .
`7/1984 (DE) .
`7/1985 (DE) .
`4/1986 (DE) .
`10/1986 (DE) .
`11/1993 (DE) .
`12/1993 (DE) .
`10/1995 (DE) .
`10/1995 (DE) .
`11/1995 (DE) .
`
`(List continued on next page.)
`
`Primary Examiner - Robert E. Nappi
`Assistant Examiner -Rita Leykin
`(74) Attorney, Agent, or Firm -Christie, Parker & Hale,
`LLP
`
`197 11 979
`
`(57)
`
`ABSTRACT
`
`There is a method for controlling the movement of electri-
`cally operated assemblies, more particularly of window
`lifters, sliding roofs or the like in motor vehicles. The
`assembly has a setting device is connected to a drive device.
`At least in one partial area of the displacement path, the
`displacement force is restricted to a predetermined maxi-
`mum value. A parameter is proportional to the displacement
`force of the electrically operated assembly. Upon reaching a
`boundary value corresponding to the maximum value of the
`displacement force over a predetermined time span, the
`parameter is regulated to a value corresponding to this
`boundary value.
`
`22 Claims, 5 Drawing Sheets
`
`
`
`US 6,236,176 Bl
`Page 2
`
`U.S. PATENT DOCUMENTS
`
`5,539,290
`5,596,253
`5,640,072
`5,682,090
`5,740,630
`5,872,436
`
`7/1996 Lu et al.
`1/1997 Mizuta et al.
`6/1997 Miyazaki et al.
`10/1997 Shigematsu et al.
`4/1998 Medebach
`2/1999 Bergmann et al.
`
`FOREIGN PATENT DOCUMENTS
`
`318/565
`318/469
`318/282
`318/468
`49/352
`318/286
`
`195 14 954
`Al
`
`12/1995 (DE) .
`
`195 36 207
`Al
`4/1996 (DE) .
`195 07 137
`9/1996 (DE) .
`0 047 812
`3/1982 (EP) .
`0 331 142 A2
`9/1989 (EP) .
`0 270 837 Al
`6/1998 (EP) .
`3/1984 (JP) .
`59- 045515
`5/1988 (JP) .
`63- 101912
`4/1992
`(JP) .
`4-126629
`(JP).
`10/1993
`5- 254347
`WO 97/12108
`4/1997 (WO) .
`* cited by examiner
`
`UUSI, LLC
`Exhibit 2030
`2/17
`
`
`
`U.S. Patent
`
`May 22, 2001
`
`Sheet 1 of 5
`
`US 6,236,176 Bl
`
`Fig. 1
`
`Fig. 2
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`MK1
`
`1/
`
`12
`
`Il
`
`'------\___MK2
`
`M1
`
`M2
`
`M
`
`UUSI, LLC
`Exhibit 2030
`3/17
`
`
`
`U.S. Patent
`
`May 22, 2001
`
`Sheet 2 of 5
`
`US 6,236,176 Bl
`
`Fig.3
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`2
`
`7
`
`5
`
`PP
`
`RAM
`
`UUSI, LLC
`Exhibit 2030
`4/17
`
`
`
`U.S. Patent
`
`May 22, 2001
`
`Sheet 3 of 5
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`US 6,236,176 Bl
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`Fig. 4
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`I, M 1
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`s1
`
`s2
`
`s3
`
`s
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`UUSI, LLC
`Exhibit 2030
`5/17
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`
`
`U.S. Patent
`
`May 22, 2001
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`Sheet 4 of 5
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`US 6,236,176 Bl
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`i, M
`
`Fig. 5
`
`-`si--+I I
`
`et
`
`s
`
`t
`
`Fig. 6a
`
`Fig.6b
`
`I, M
`
`I, M
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`ZEE
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`í
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`I
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`6s=0
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`s
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`Fig.7a
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`I,M
`
`Fig.7b
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`I, M
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`Á!IIA!iL!
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`At
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`et°
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`
`s
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`UUSI, LLC
`Exhibit 2030
`6/17
`
`
`
`U.S. Patent
`
`May 22, 2001
`
`Sheet 5 of 5
`
`US 6,236,176 Bl
`
`Fig. 9
`
`UUSI, LLC
`Exhibit 2030
`7/17
`
`
`
`US 6,236,176 Bl
`
`1
`METHOD FOR ELECTRONIC CONTROL
`AND ADJUSTMENT OF THE MOVEMENT
`OF ELECTRICALLY ACTUATED UNITS
`
`FIELD OF THE INVENTION
`The invention relates to a method for controlling and
`regulating the movement of electrically operated assemblies,
`more particularly window lifters, sun roofs or the like in
`motor vehicles.
`
`5
`
`io
`
`BACKGROUND OF THE INVENTION
`
`15
`
`From DE 30 34 118 Al a method is known for electroni-
`cally operating and monitoring the opening and closing
`cycle of electrically operated assemblies, such as window
`lifters and electric sun roofs in motor vehicles. The path
`covered during opening of the assembly is electronically
`captured. During closing of the assembly, the captured
`opening path is compared electronically with the closing
`path which has been covered. The opening and closing path
`of the assembly is, for this purpose, divided up into three
`areas of which the first area runs from half opened to fully
`opened, the second area runs from half opened to practically
`fully closed and the third area runs from practically fully
`closed to completely closed.
`In the first and third areas, the blocked state, which
`represents the fully opened and fully closed assembly, is
`detected and a setting member of the assembly is switched
`off. In the second area, the speed of a servo drive of the
`assembly is detected and, in the event of a reduction in the
`speed, the servo drive is switched off.
`With this known method for producing a so- called "anti -
`jam protection," the servo drive is designed with regard to
`its power so that the mechanical resistances which are
`conditioned by the type of assembly and through outside
`influences are overcome over the entire displacement area.
`For this reason, the servo drive is designed with its power
`output significantly greater than is necessary for most of the
`displacement range. This in turn has the result that a part of
`the body present in the displacement area is jammed with a
`very high force by the assembly part which is being dis-
`placed.
`A further drawback with this known method is that in the
`third area, that is as the window pane or sliding roof enters 45
`into the seal area for completely closing the window or roof,
`only the blocking state and not, however, an anti -jam state
`is detected.
`From DE 195 07 137 Al, a method is known for moni-
`toring and controlling the opening and closing process of 50
`electrically operated assemblies provided in motor vehicles.
`The power of the servo motor is controlled so that the
`displacement speed of the setting member is adjustable over
`its displacement path, in dependence on predetermined
`positions of the assembly. In this way, the force exerted in
`the jamming state by the assembly part, which is to be
`displaced, is to be restricted to a minimum over critical areas
`of the displacement path, so that the critical area is covered
`more slowly and thus more sensitively.
`This method does indeed allow a "soft inlet" into the seal 60
`area, that is a slow displacement speed of the assembly part
`being displaced in the area of the seal inlet, in order to meet
`the requirements which are specific to individual countries
`with regard to an effective anti -jam protection. The slow
`inlet of the assembly part being displaced into the seal area,
`however, makes it difficult to almost impossible to recognize
`a standardized 4 mm round tube to determine the efficiency
`
`20
`
`25
`
`30
`
`35
`
`ao
`
`55
`
`65
`
`2
`of the anti -jam protection and to safely distinguish the
`influences of the displacement forces in the sealing area.
`This is particularly true in the case of frameless doors and
`doors with panes on the outside. Furthermore, the known
`method leads to faulty releases of the anti -jam protection
`with subsequent reversing of the assembly being displaced
`during entry into the seal. Furthermore, the closing time of
`the window is increased.
`From DE 35 32 078 C2, a control method is known for
`controlling the drive of windows or doors with an electric
`motor. A drive current is measured during the closing
`movement and the change in power is checked at constant
`time intervals by setting a current change boundary value.
`To this end, a minimum current value is predetermined
`inside a constant period, to which is added a fixed amount
`and the total sum is set or laid down as the reference value
`for detecting an abnormal motor load. If this boundary value
`is exceeded, then the closing movement is switched over to
`an opening movement.
`The drawback with this known control method is that
`likewise temporary disturbances during a closing
`movement, which are traced back to external influences or
`temporary heavy going (operational difficulties) of the
`system, but without a jamming state existing, are substan-
`tially not recognized and lead to an opening movement
`although the closing movement could be continued.
`From DE 41 12 998 Al, a method is known for controlling
`a gate drive which has a setting device, a drive device
`connected with the setting device, as well as a control and
`evaluator electronics for evaluating measuring signals and
`for producing control commands. To displace a gate oper-
`ated by means of the gate drive, a displacement force is
`applied the amount of which is selected in dependence on
`the displacement path.
`Should the displacement force exceed a predetermined
`safety limit, then the drive device is switched off or the drive
`device is reversed. This safety limit is formed by the sum of
`the displacement force dependent on the displacement path
`and a constant additional force. In this way, it is possible to
`compensate for interference by environmental or seasonal
`factors, without resulting in a premature safety cut -off.
`With this known method, interference through environ-
`mental or seasonal factors are indeed taken into
`consideration, but the drive device is switched off every time
`the safety limit is exceeded. Also, here only a temporary
`disruption, during a closing movement which is due to
`outside influences or temporary difficulties in the system
`without a jamming case existing, is not recognized. This
`leads to a cut -off or reversion, although the closing move-
`ment could be continued.
`
`SUMMARY OF THE INVENTION
`The object of the invention is to provide a method of the
`kind already mentioned wherein over the entire displace-
`ment area of a setting device, an anti -jam protection is
`guaranteed. The anti -jam protection satisfies even the most
`stringent safety requirements, but rules out, as far as
`possible, a faulty reversing or stopping of the setting device
`based on external influences, variable resistances or too little
`displacement force in the displacement area.
`The solution according to the invention ensures, over the
`entire displacement area of the setting device, an anti -jam
`protection which satisfies the most stringent of safety
`requirements. At the same time, the anti -jam protection
`ensures that the setting device opens or closes an electrically
`operated assembly with sufficient displacement force inde-
`
`UUSI, LLC
`Exhibit 2030
`8/17
`
`
`
`US 6,236,176 Bl
`
`5
`
`3
`pendently of external influences and variable resistances in
`the displacement area, at the discretion of the operator.
`Substantially eliminating external influences and different
`resistances in the displacement area ensures that even when
`the electrically operated assembly is stationary, despite a
`predetermined closing impulse, a regulated closing process
`takes place over a predetermined time interval. In this
`additional time interval, however, the predetermined maxi-
`mum value of the displacement force is not exceeded until
`either further movement of the electrically operated assem- 10
`bly takes place, or in the event of a continued stationary state
`of the electrically operated assembly, a drive device is
`switched off.
`Parameters proportional to the displacement force of the
`electrically operated assembly are, for example, the current
`taken up by the drive device of the electrically operated
`assembly or the torque delivered by the drive device. Param-
`eters correlated with the dynamics of the setting device of
`the electrically operated assembly are, for example, the
`speed or acceleration of the displacement device or assem-
`bly.
`The excess force restriction can be restricted to a partial
`area of the displacement path, since, for example, the
`jamming of larger parts of the body need not be considered
`when opening the electrically operated assembly and in the
`area adjoining the completely opened state of the assembly.
`From U.S. Pat. No. 5,410,229, a circuit arrangement for
`controlling the speed of an electric motor is known wherein
`the motor is stopped on reaching a predetermined counter
`torque. For this purpose, the motor current is controlled in
`pulse width modulation in dependence on the captured speed
`of the electric motor and a predetermined maximum torque.
`However, with this electronic coupling, the motor current
`is constantly interrupted when the predetermined maximum
`torque is reached, so that when used for an electrically
`operated assembly in motor vehicles, a closing movement
`would be interrupted. For example, if as a result of external
`influences the counter torque reaches a corresponding value,
`a window pane could not be completely closed. On the other
`hand, with a correspondingly high value of the permissible
`counter torque, an inadmissible jamming force would act on
`a part of the body located in the displacement area of the
`electrically operated assembly, so that the known control
`circuit would be unsuitable for the present case.
`In DE 196 15 581 Al, which has an earlier priority, a
`method is described for controlling electrical drives in motor
`vehicles with an electric motor whose controlled operation
`is provided by a torque /speed characteristic line and wherein
`the active torque is monitored. With a boundary torque
`which is greater than the torque normally occurring and
`clearly lower than the maximum torque the drive is regu-
`lated to an approximately constant torque.
`With this method, first a boundary torque is fixed, that is
`a static boundary value is predetermined for the boundary
`torque. Compared to this, the present invention claims the
`provision of a dynamic boundary value which takes into
`account, by way of adaptation, a slight excess force. The
`dynamic boundary value is changeable with each opening or
`closing process, so that to produce an anti-jam protection, a 60
`small clamping force of any size is guaranteed without the
`drive device undesirably coming to a standstill as a result of
`too little displacement force in dependence on the displace-
`ment path.
`The parameter proportional with the displacement force is 65
`preferably regulated upon reaching a predetermined bound-
`ary value dependent on the displacement position (envelope
`
`15
`
`20
`
`25
`
`30
`
`35
`
`40
`
`45
`
`50
`
`55
`
`4
`curve b). The predetermined boundary value corresponds to
`the maximum excess force permissible at the relevant dis-
`placement position.
`The boundary value regulation of the parameter propor-
`tional with the displacement force takes place within the
`predetermined time span until either the parameter under -
`steps (or falls below) the predetermined boundary again, or
`either the setting device or the drive device has come to a
`standstill. The position- dependent regulation of the excess
`force thereby takes into account the normal displacement
`force required for displacing the assembly. As a result, with
`a corresponding restriction of the excess force, even in the
`most unfavorable case, a jamming state always remains in
`the harmless area.
`The interruption of the current delivered to the drive
`device and /or reversing the rotary direction of the drive
`device is preferably delayed by a time interval AtO. The drive
`device sends out a constant torque to the setting device
`during the duration of the delay.
`The time interval At0 is preferably measured so that a
`satisfactory differentiation can be made between a jamming
`case and an external, temporary (dynamic) fault.
`A further advantageous development of the solution
`according to the invention is characterized in that the
`boundary value of the parameter is increased by a predeter-
`mined amount when the setting device or the drive device
`has come to a standstill and a control impulse is delivered
`within the predetermined time span by an operating device,
`which causes the electrically operated assembly to be closed.
`This development of the solution according to the inven-
`tion provides an increase in the drive power in the event that,
`during the time duration of the boundary value regulation
`within the predetermined time interval, an increased ideal
`value is produced when the operating person, despite a
`standstill of the electrically operated assembly, creates a
`switch impulse controlling the closing movement, i.e. wants
`to carry out a closing of the electrically operated assembly.
`An advantageous development of the solution according
`to the invention is characterized in that the parameter
`corresponds to the current supplied to an electric motor as
`the drive device, so that the current collection of the electric
`motor is restricted to a value which corresponds to a
`maximum resulting excess force.
`Restricting the current collection of the electric motor to
`a value which corresponds to a maximum resulting excess
`force can take place in that the maximum value of the
`current delivered to the electric motor is set at a value
`corresponding to the maximum resulting excess force or in
`the event of a pulse width modulation of the current deliv-
`ered to the electric motor, the peak value (maximum value),
`the arithmetic mean value or quadratic mean value (effective
`value) of the current is set to a value corresponding to the
`maximum resulting excess force. In another alternative, the
`maximum value, the arithmetic mean value or the quadratic
`mean value of the current is predetermined depending on the
`position of the setting device.
`Restricting the current collection of the electric motor to
`a value corresponding to the maximum resulting excess
`force ensures that the setting device carries out the desired
`displacement movement without the force, which extends
`beyond the required displacement force, being able to rep-
`resent a danger for parts of the body present in the displace-
`ment area in the event of jamming.
`From U.S. Pat. No. 5,268,623, a circuit arrangement is
`known for controlling a direct current motor with a current
`restricting device which governs the direct current motor
`
`UUSI, LLC
`Exhibit 2030
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`
`
`
`US 6,236,176 Bl
`
`5
`with current blocks with varying pulse duration /pulse pause
`ratio. In the event of a blocking of the direct current motor,
`the pulse duration /pulse pause ratio is reduced so that neither
`the motor overheats nor does the starting current, at the
`start -up of the direct current motor, adopt too high a value.
`With this known control method, when the direct current
`motor is blocked, the current supply to the motor is not
`interrupted. The arithmetic mean value of the current sup-
`plied to the direct current motor in the pulse width modu-
`lation is always reduced to a value which is harmless for the
`direct current motor when a blocked state occurs, that is any
`counter torque detected as a blocked state leads to a reduc-
`tion of the motor torque to a fixed value. In the present case,
`in relation to the window entering into the seal area with
`increased resistance detected as a blocked state, no complete
`closing of the window pane would result.
`Compared to this, however, the method according to the
`invention guarantees the implementation of the desired
`displacement path that depends on different resistances or
`counter torques appearing in the displacement path, because
`there is always an excess force. The excess force is a force
`which exceeds the force required for the displacement
`movement by a predetermined amount. The amount of the
`excess force can thereby remain constant over the entire
`displacement path, when the drive force required for the
`displacement movement is adapted to the displacement
`resistances over the displacement path. This excess force is
`measured so that it satisfies at any location in the displace-
`ment path the most stringent anti -jam protection require-
`ments so that, even in critical areas, both the completion of
`the desired displacement movement and an effective anti -
`jam protection are guaranteed.
`The displacement force and /or the excess force can,
`according to a feature of the method according to the
`invention, be predetermined in dependence on the motor
`voltage, the motor speed, and /or the motor temperature or
`the surrounding temperature. The detection of these values
`makes it possible to take into account outside or system -
`imminent influences when implementing a displacement
`movement by taking into account both the anti -jam protec-
`tion and also a safe implementation of the displacement
`movement.
`The electric motor is preferably classified at a testing
`station with regard to at least a characteristic feature (e.g.
`rise or slope in the motor characteristic line). The at least one
`characteristic feature is used to calculate an envelope curve
`restricting the excess force.
`A particularly advantageous development of the method
`according to the invention is characterized in that the motor
`characteristic line of the electric motor is recorded over the
`displacement path of the setting device and is stored. An
`amount of the current corresponding to the maximum result-
`ing excess force is added to the motor current of the motor
`characteristic line corresponding to the relevant motor
`torque at that time. The current delivered to the electric
`motor is restricted over the at least one partial area of the
`displacement path to this resulting maximum value of the
`current.
`The restriction of the maximum motor torque and thus the
`restriction of the maximum excess force of the electrically
`operated assembly can take place, according to this method
`feature, by a position- dependent fixing of the maximum
`value of the current supply to the electric motor. The
`position- dependent maximum value is determined in a
`defined "measuring stroke." To this end, the normal curve
`for the current collection is determined through the imple-
`
`s
`
`3
`
`0
`
`3
`
`5
`
`15
`
`6
`mentation of a complete displacement movement in a stan-
`dardizing run. The relevant maximum value of the current
`collection or current supply to the electric motor is deter-
`mined by taking into account the restricted excess force
`through an envelope curve which is calculated by including
`the various influencing factors.
`To these influencing factors belong, for example, the
`voltage, the speed, the preliminary resistance, the motor and
`surrounding temperature as well as the specific motor char -
`lo acteristic line which is inherent to each electric motor and
`which can undergo considerable fluctuations. This motor
`characteristic line can, where applicable, be individually
`determined at a motor testing station in production so that
`fixing the maximum motor current with a sufficient
`restricted excess force, taking into account an active antijam
`protection, can be adapted individually to each relevant
`electric motor.
`The resulting or maximum excess force can be adapted
`selectively, also adaptively, to the different resistances in the
`20 displacement area throughout the service life. The current
`collection of the electric motor is detected over the displace-
`ment area and is stored as a value pair with the relevant
`position of the displacement device. In this way,
`is
`it
`possible to detect areas of heavy going in the lift area and /or
`25 heavy going in the area of an inlet into the seal and thus to
`fix, adaptively, the displacement force required for the
`displacement movement and the resulting excess force.
`A further advantageous development of the solution is
`characterized in that the envelope curve restricting the
`excess force is set high when the speed of the electrically
`operated assembly, after reaching the predetermined bound-
`ary value, is not reduced by the parameter, or the negative
`acceleration does not exceed a boundary value. Raising the
`envelope curve can thereby take place by a predetermined
`amount or until the speed of the electrically operated assem-
`bly has reached a certain value.
`This further development of the solution according to the
`invention takes into consideration that, as a result of external
`influences or system- conditioned resistances in the displace-
`ment area, the parameter which is proportional to the dis-
`placement force does indeed reach the predetermined
`boundary value. However, either the speed of the electrically
`operated assembly is not reduced or the braking of the
`45 system caused by the resistances does not extend beyond a
`certain amount. This leads to a reduction of the boundary
`value in order to take into account this heavy going caused
`by the external influences or additional resistances in the
`displacement area.
`Through the position -related detection of delays (heavy
`going) of the electrically operated assembly and storage of
`the detected values, it is possible to change the path of the
`envelope curve adaptively.
`A further development of the solution according to the
`55 invention is characterized in that, upon reaching the prede-
`termined maximum value, the arithmetic mean value or the
`effective value of the current collected by the electric motor,
`the current delivered to the electric motor is interrupted
`and /or the rotary direction of the electric motor is reversed.
`If, according to this feature of the method according to the
`invention, the motor current reaches the fixed or calculated
`maximum value, the motor current is restricted and kept
`constant. This development of the solution according to the
`invention always proves expedient when a reliable differ -
`65 entiation between areas of heavy going action, for example,
`when entering into the seal, and a jammed state is not
`possible. Since the excess force, in the case of a restricted
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`UUSI, LLC
`Exhibit 2030
`10/17
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`US 6,236,176 Bl
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`7
`current which is kept constant is, however, always less than
`a predetermined boundary value, the risk of a part of the
`body becoming jammed does not arise even in the most
`unfavorable cases.
`According to a further development of the method accord-
`ing to the invention, after reaching the fixed or calculated
`maximum value of the motor current, an immediate or
`time -delayed reversal of the displacement device can take
`place. In particular, the time -delayed reverse serves to screen
`out dynamic disruptions which appear, for example, as a
`result of short -term negative accelerations through potholes
`or short -term disturbances in the event of a lifting movement
`of the electrically operated assembly.
`A constant torque is preferably delivered to the displace-
`ment device during the deceleration of the displacement
`motor.
`According to a further feature of the method according to
`the invention, the rise in the motor torque can be delayed so
`that the excess force of the electrically operated assembly
`only rises slowly. A restriction of the motor current rise
`(di /dt) connected therewith can preferably be produced
`through a corresponding switch element, such as a rhythmic
`semi -conductor, a controllable resistance or the like.
`A pulse width control of the motor current, by means of
`a semiconductor switch allows the fixed or calculated maxi-
`mum value of the motor current to be adapted over the entire
`displacement area of the electrically operated assembly in
`the shortest possible time and thus in small position- change
`steps. A circuit arrangement of this kind furthermore ensures
`a simple construction or a simple programming of the
`control electronics taking into account the most varied of
`influencing factors, which can be additionally detected or
`taken into account within the framework of an adaptive
`control.
`Since the same current flows through the semiconductor
`switch as through the servo motor, it
`is also possible to
`achieve a simple overheating protection for the displacement
`motor, particularly as many known power semiconductor
`switches detect the actual operating temperature in order to
`prevent a thermal breakdown of the semiconductor switch.
`A semiconductor switch without temperature detection, can
`be coupled thermally, for example, to a temperature -
`dependent resistor or the like, in order to switch offset
`semiconductor switch upon reaching a critical temperature
`and thus to interrupt the further supply of current to the
`displacement motor.
`Instead of measuring current to regulate the scanning ratio
`of the pulse width modulation, the scanning ratio can be
`calculated from the idling speed, the actual speed and the
`motor characteristic line of the electric motor, and thus a
`device for detecting the motor current can be spared.
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`BRIEF DESCRIPTION OF THE DRAWINGS
`The idea underlying the invention will now be explained
`in further detail with reference to the embodiment shown in
`the drawings in which:
`FIG. 1 shows a diagrammatic view of various displace-
`ment areas in a window lifter system;
`FIG. 2 shows a graphic representation of two different
`motor characteristic lines;
`FIG. 3 shows a diagrammatic illustration of a circuit
`arrangement for controlling a window lifter system;
`FIG. 4 shows a diagrammatic illustration of the motor 65
`current or motor torque versus the displacement path of a
`window lifter system;
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`FIG. 5 shows a diagrammatic view of the motor current
`or motor torque over the displacement path and over the
`displacement time with the boundary value regulation reg-
`istered therein;
`FIG. 6 shows a diagrammatic view of a boundary value
`regulation in the event of "hard jamming ";
`FIG. 7 shows a diagrammatic illustration of the boundary
`value regulation in the event of "soft jamming" or heavy
`going in the displacement area;
`FIG. 8 shows a diagrammatic view of the boundary value
`regulation in the event of a temporary outside influence and
`FIG. 9 shows a graph for determining the scanning ratio
`of a pulse width modulation from the idling speed and the
`actual speed of an electric motor.
`
`DETAILED DESCRIPTION OF THE
`PREFERRED EMBODIMENT
`The displacement areas shown in FIG. 1 are covered by
`a window pane during opening and closing of the window
`pane in the door of a motor vehicle. The displacement areas
`can basically be divided into three areas, Area A reaches
`from the fully opened window pane to a window pane closed
`by a third. Area B extends from the window pane closed by
`a third up to shortly before the window pane enters the
`window seal. Area C extends over the sealing area.
`For an anti -jam protection there are basically two areas B
`and C which are relevant during closing of the window,
`while in area A, as a result of the large distance between the
`upper edge of the window pane and the door frame, the
`jamming of larger parts of the body can be ruled out.
`However, area A can also be included in the monitoring and
`control for an anti -jam protection.
`In the area part B when a jamming state exists, it must be
`ensured that the force acting on the jammed object or the
`jammed part of the body must not exceed a certain prede-
`termined amount and the lifting and lowering of the window
`must be guaranteed against motion resistances of the win-
`dow lifter system, and where applicable, external influences.
`In the area part C, special conditions apply since here, as a
`result of the increased resistance when the window pane
`runs into the seal, on the one hand a secure closing of the
`window pane must be ensured, and on the other for safety
`reasons a 4 mm bar must be recognized and reliably distin-
`guished from the influences of the displacement forces in the
`sealing area.
`When establishing the displacement forces required for
`opening and closing, for example, a window lifter system in
`addition to external influences such as surrounding
`temperature, resistances when traveling over the displace-
`ment path, temperature of the displacement motor, etc., of
`particular importance is the motor characteristic line of the
`displacement motor whose characteristic line is subject to
`considerable specimen variations.
`FIG. 2 shows, by way of a diagrammatic example, the
`motor characteristic line of two different electric motors
`which collect up different motor currents to reach a matching
`motor torque M. For a position- dependent "normal" torque
`Ml, the one electric motor with the motor ch