DE102009020538A1 - Variable powerless operative connection adjusting method for brake of e.g. door of motor vehicle, involves determining correction current from one of tables based on determined reference value and target value - Google Patents

Abstract

The method involves a temporarily adjusting a correction current of a coil and reducing to zero for adjusting a desired residual magnetic induction of a housing (16) and a field producing component (18). A powerless operative connection is made between a fastening element (12), the housing and the component (18), and another fastening element (14) and a pot lamella (26). A reference value is determined depending on the operating point from a table. The correction current is determined from another table based on the determined reference value and a target value. An independent claim is also included for an arresting system with a magnetorheological holding device for a door or a flap.

Description

The The invention relates to a magnetorheological holding device and a method for setting a variable currentless active connection in a magnetorheological holding device.

A Magnetorheological holding device usually includes a first element and a second element that are relative to each other are mobile. For example, if one element is is a rotor and the other element is a stator, Thus, the holding device forms a brake. If both are For example, elements are rotatably mounted, so is a clutch in front. The magnetorheological holding device further comprises a magnetorheological medium, for example a magnetorheological fluid or a magnetorheological powder. The two elements are with the magnetorheological medium in contact. By creating a Magnetic field increases the viscosity of the magnetorheological Fluid or the magnetic powder solidifies, so that the first element and the second element enter into an increasingly firm operative connection. For this purpose, such a holding device further a magnetic field generator in the form of a coil and an associated Power supply. By generating an electric current in the Coil can be the magnetic field acting on the magnetorheological medium be generated.

From the DE 100 29 227 A1 a controllable braking system is known in which by means of a permanent magnet constantly a magnetic field is generated at the location of the magnetorheological medium. As a result, there is basically an operative connection between the two elements, which are in contact with the magnetorheological medium. In order to be able to temporarily cancel this active connection, a coil is provided which, when energized, generates an opposing field to the magnetic field of the permanent magnet. However, in order to temporarily neutralize the magnetic field of the permanent magnet, sufficiently large magnetic fields are necessary. In addition, an intact power supply is required in order to temporarily cancel the operative connection between the two elements.

From the DE 10 2006 037 992 A1 , the contents of which are hereby included in the disclosure of the present application, it is therefore known to provide for the holding device a magnetizable component with remanent magnetic properties. The coil and the magnetizable component of this holding device cooperate in such a way that at least one electroless state can be generated, in which the magnetizable component still provides a magnetic field after its magnetization, which serves to maintain the operative connection between the first element and the second element by means of the magnetorheological Medium is sufficient. Optionally, at least one further currentless state can be generated, in which the magnetizable component is again substantially demagnetized, whereby the operative connection between the first and the second element can be canceled. Thus, a de-energized state with existing operative connection between the two elements and a de-energized state without operative connection between the two elements can be produced. In other words, either a coupled state or a decoupled state can be set between the two elements, wherein for the maintenance of the respective state no power supply is required and thus no energy is consumed.

at Such a holding device is basically also possible intermediate states between said set coupled state and said decoupled state. Of the However, the use of materials with retentive properties requires that the relationship between the coil current and the applied magnetic field on the one hand and the magnetic induction or the generated magnetization on the other hand is formed by a hysteresis loop. A simple one Characteristic control leads to unsatisfactory positioning accuracies, especially when a remanence induction is to be set, which lies below the saturation remanence.

It is an object, setting a variable current-free active connection between two elements of a magnetorheological holding device to allow in a simple yet accurate way.

This object is achieved in that in a first step, starting from a current operating point of the holding device, the coil current is reduced to zero to set a preliminary remanent magnetic induction of the magnetizable component, and that in a subsequent second step, a correction current of the coil temporarily set and is reduced again to zero to set a desired remanent magnetic induction of the magnetizable component from the provisional remanent magnetic induction, so that a current-free operative connection between the first element and the second element is made, depending on said current operating point of a first stored table is a reference value is determined, which represents the set in the first step provisional remanent magnetic induction, and wherein in dependence on the determined reference value and a target value representing the desired magnetic induction is determined from a second stored table of the correction current to be temporarily set in the second step.

at the controller of the invention is in a first step starting from any current operating point the holding device - d. H. starting from the current one Position along or within the hysteresis loop of the holding device - the Coil current reduced to zero. This will do so from the outside magnetic field applied to the magnetorheological medium to zero set, leaving a preliminary remanent magnetic Induction of the magnetizable component of the holding device set becomes. Provided the magnetizable component is completely complete was magnetized (reaching the saturation magnetization), This sets the saturation remanence of the magnetizable Component. If the magnetizable component before said first step, however, was magnetized to a lesser degree, the shutdown of the coil current results in a preliminary one remanent magnetic induction whose value is less than that Saturation remanence. A reference value, this in the first Step set preliminary remanent magnetic induction represents, depending on the operating point, which formed the starting point of said first step, read out from a first stored table.

In after the first step second step, a correction current of the coil is set for a short time and then reduced to zero again. This is starting from the previously set provisional remanent magnetic Induction now a desirable - d. H. selected - retentive magnetic induction of the magnetizable component set. In other words, thereby a de-energized state of the holding device adjusted, the desired active connection between corresponds to the first element and the second element. The actual Remanent magnetic induction of the magnetizable component is thereby adapted to a desired value, for example, from a higher-level control device is specified. For this purpose, depending on the mentioned first stored table and reference value said setpoint from a second stored table the one Correction current read in the second step temporarily is set.

One particular advantage of this control is that only two tables have to be read out and taken into account, to starting from any operating point of the holding device a selectable electroless active compound between the set both mutually movable elements of the holding device to be able to. The two tables can be as respective Look-up table (LUT) in a storage device be deposited. The respective table values can be empirical be determined. The two tables can be a simple one Structure with a small number of values, as appropriate the explained implementation of the tax procedure in two steps the two tables are read one after the other, wherein the output value of the first readout operation is an input value forms the second readout operation.

In the first table is the reference value in dependence stored from the coordinates of the operating point of the holding device. The operating point in the hysteresis diagram is, for example, one by the current coil current, the current field strength the magnetic field generated by the coil or any other equivalent thereto Size set. On the other hand, the working point the holding device beispielswei se by the current magnetic Induction of the magnetizable component, by the current Degree of magnetization of the magnetizable component that is currently effective holding torque between the two elements of the holding device, the currently effective between the two elements holding power or another size equivalent thereto established.

On Basis of the value of one of the sizes of the aforementioned first group of equivalent sizes and the value of one of the mutually equivalent quantities the aforementioned second group can from the first table of reference value read out. As reference value itself in turn can directly determine the value of the magnetic induction of be used magnetizable component. Or it will be one this equivalent value used, for example, the Value of the degree of magnetization of the magnetizable component or the value of the effective holding moment or the effective holding force between the two elements.

From the second table mentioned, the correction current to be temporarily set in the second step is read out, as a function of the reference value determined on the basis of the first table and on the basis of the stated desired value, which represents the desired magnetic induction of the magnetizable component. The desired value does not have to be directly a value of the desired magnetizable induction of the magnetizable component, but it may also be an equivalent value, for example a value of the desired degree of magnetization of the magnetizable component Value of the desired holding moment between the two elements or a value of the desired holding force between the two elements.

For the correction current - ie for the output value the second table - can be for example values the polarity and the amplitude of the correction current to be set be saved. In addition, values of the Duration of the correction current to be set to be stored. Alternatively, a fixed period of time is provided for the respective current pulse, so that no individual values of the duration are stored have to.

The said first element and the second element of the holding device can be rotatable, pivotable, movable relative to each other or be arranged displaceable in any other way. Accordingly this is the currentless active compound to be adjusted between these two elements by a holding force or a holding torque.

at said magnetizable component of the holding device, which has the explained remanent properties, it does not necessarily have to be a separate element. Rather, it is advantageous if the magnetizable component is formed by said first or second element.

The The invention relates to a method with a control of explained type and on a holding device with a appropriately trained control device. Further, refers the invention relates to a retention system with such a holding device for a door or a flap that is attached to a relative fixed structure therefor (eg body section of a motor vehicle) pivotally hinged, said first or second Element together with the door or the flap at least moved indirectly (eg via a gear), and wherein the respective other element attached to the fixed structure is.

The The invention will now be described by way of example only explained on the drawings.

1 shows a side sectional view of an embodiment of a magnetorheological holding device;

2 shows a diagram of the magnetic induction versus the external magnetic field;

3 shows a block diagram of a magnetorheological holding device with associated power supply, control device and memory device; and

4 shows a flowchart of a control method.

1 shows a magnetorheological holding device in the form of a door brake 10 as used for example in a door or a flap of a motor vehicle. By means of a fastener 12 is the door brake 10 for example, attached to the body. On the fastener 12 is a cup-shaped housing 16 provided, which opens upwards. In it is on the ground a field-generating component (coil core) 18 firmly mounted, leaving an annular gap between the housing 16 and field-generating component 18 remains. The field-generating component 18 includes a coil 20 , which in the example shown from a number of suitable interconnected coil wire groups 21 composed in grooves in the field-generating component 18 are arranged. The coil is over the supply lines 22 . 24 powered. Only indicated schematically is the fastening screw 36 with which the fastener 12 , the housing 16 and the field-generating part 18 are firmly screwed together.

In the cylindrical gap between the housing 16 and the field-generating component 18 protrudes a pan top 26 that with a fastener 14 is connected, which is provided on a pivotable part, for example on a vehicle door. In a known manner are in stock 29 the fastener 14 and the fixed parts 12 . 16 . 18 rotatably mounted to each other. In particular, the arrangement has a degree 34 on, with which the fastener 14 sealing but rotatable on the housing 16 is applied. numeral 30 denotes the axis about which the fastener 14 together with the topflamelle 26 is pivotable. The topflamelle 26 rests on a plain bearing 32 in the case 16 from. Instead of the direct connection of the Topflamelle 26 with the fastener 14 can also be provided an indirect connection, for example via a planetary gear. Instead of a single topflamelle 26 can also be provided several top plates of different diameters in a coaxial arrangement.

At the door brake 10 according to 1 forms the fastener 12 with the housing 16 and the field-generating component 18 thus a first element, and the fastener 14 with the topflamelle 26 forms a second element, wherein the first element and the second element are pivotable relative to each other.

In the camp 29 can be a rotation angle sensor 28 be provided for measuring the pivoting of the fastener 14 with Be train to the fixed parts 12 . 16 . 18 serves.

In the space between the field-generating element 18 and the housing 16 is magnetorheological fluid 38 where the with the fastener 14 connected topflamella 26 into the magnetorheological fluid 38 protrudes. Instead of a magnetorheological fluid 38 It is also possible to use a magnetorheological powder.

numeral 40 denotes an exemplary magnetic field line as given by a group of coil wires 21 is produced. Also, the other marked groups of coil wires, the total of the coil 20 result, generate corresponding magnetic field lines. For the sake of clarity, however, not all magnetic field lines are around the groups 21 located.

Both the field-generating element 18 as well as the case 16 are made of a magnetizable material with high saturation remanence and a narrow hysteresis curve. Such a material is, for example, a tempering steel V155 from Böhler Edelstahl GmbH & Co. KG, Kapfenberg (Austria). Preferably, the field-generating element 18 and the case 16 a saturation remanence in the range of about 0.5 to 2 T (Tesla). Saturation remanence (usual abbreviation: B _R ) is the magnetic induction which is still present when the externally applied magnetic field is reduced to a field strength of zero (H = 0), based on a saturation magnetization of the magnetizable component after complete magnetization becomes. Furthermore, it is preferred if the field-generating element 18 and the case 16 have a coercive force in the range of about 10 ³ to 10 ⁴ A / m. Coercive field strength (usual abbreviation: H _K or H _C ) is the magnetic field strength for which - starting from a saturation magnetization of the magnetizable component after a complete magnetization - a magnetic induction (usually abbreviation: B, unit: T = Tesla) or a magnetization (M) of zero.

Thus, the magnetizable component (field-generating element 18 and housing 16 On the one hand - in contrast to a permanent magnet - magnetically soft (relatively low coercive force), so that the required for the desired magnetization and demagnetization coil 20 can be dimensioned small and low currents can be used. The hysteresis loop of the magnetizable component is thus narrower than in a permanent magnet. On the other hand, a saturation remanence of about 0.5 to 2 T means a comparatively strong magnetic field and thus an advantageously strong active connection between the first element (FIG. 12 . 16 . 18 ) and the second element ( 14 . 26 ) Even in the de-energized state or only low energization of the coil.

The embodiment according to 1 is generally used as follows. The hinged fastener 14 is - as already mentioned - for example connected to a vehicle door, while the fixed fastener 12 attached to the body. First, the vehicle door is closed. At the coil 20 There is no power. The vehicle door is now opened. In the open state is via the power lines 22 to the coil 20 an electric current is applied which generates a magnetic field, as exemplified by the wire winding group 21 with the reference number 40 is designated. The magnetic field leading parts, in particular the field-generating component 18 and the case 16 , are magnetized. In this case, an essentially complete magnetization of the field-generating component preferably takes place 18 and the housing 16 (Reaching the saturation magnetization). The resulting magnetic field solidifies the magnetorheological fluid 38 , That by means of the coil 20 generated magnetic field can then be switched off. Nevertheless, at the location of the magnetorheological fluid 38 by the magnetization of the field-generating element 18 and the housing 16 maintain a magnetic field that is the magnetorheological fluid 38 holds in a solidified state. The vehicle door is thus kept in the open state (de-energized hold state).

For closing the vehicle door, the holding force must be reduced, which from the remanent magnetization of the field-generating component 18 and the housing 16 and from the resulting mechanical active connection with the panflat 26 results. This is the coil 20 initially energized such that by generating the required coercive force in the magnetizable component at the location of the magnetorheological fluid 38 effective magnetic field is reduced and remains reduced until the door is locked properly, ie the coil remains initially energized. The door is then held closed by the latch. By subsequently generating an alternating field of decreasing strength, for example by energizing the coil 20 with an alternating current of decreasing intensity, the magnetization of the field-generating component becomes 18 and the housing 16 gradually shut down, as is the hysteresis curve of the 2 is shown in the sequence a to e. The door can now be opened at any time by unlocking the latch without the coil being energized 20 is required.

2 shows a hysteresis loop known per se 120 with a new curve 122 , The vertical axis shows the magnetic induction B of the magnetizable component (field-generating element 18 and housing 16 ). The magnetic induction B is synonymous with the magnetic flux density. Instead of the magnetic induction B could in equi valenter representation of the magnetization or between the elements 12 . 16 . 18 respectively. 14 . 26 produced active connection (holding force or holding torque) are applied to the vertical axis. The horizontal axis in 2 gives the field strength H of the coil 20 generated magnetic field again. Instead of the field strength H, the coil current on the horizontal axis could be presented in an equivalent representation. The magnetic induction B ultimately corresponds to the sum of the externally applied magnetic field and the magnetic field resulting from the magnetization of the magnetizable component. The axis section on the vertical axis indicates the saturation remanence while the axis section on the horizontal axis corresponds to the coercive field.

For demagnetization, for example, the curve a, b, c, d, e is passed through. In this way, a substantially demagnetized state can be achieved. A possibly remaining small residual magnetization, which can not be canceled in this way, is harmless if it is chosen so small that the viscosity of the magnetorheological fluid 38 in the magnetic field of the magnetizable component 16 . 18 compared to the magnetic field-free case is only slightly increased. The most complete possible demagnetization of the magnetizable components, in this embodiment, therefore, of the field-generating element 18 and the housing 16 , thus, leads to the location of the magnetorheological fluid 38 no magnetic field is more effective and thus the topflamella 26 no longer in the magnetorheological fluid 38 is held. A free movement of the pivotable fastening element 14 is possible then.

The above-described electroless holding state of the door brake 10 has the advantage that by using a material with remanent egg properties a holding torque (remanence moment Mr) between said first element (fastener 12 with the housing 16 and the field-generating component 18 ) and said second element (fastener 14 with the topflamelle 26 ) is produced without the coil for this purpose 20 must be energized. It may be desirable to set different such currentless holding states, ie, holding torques of different magnitudes at a respective coil current zero, for example if this is intended to simulate a plurality of different latching positions of a vehicle door. Due to the hysteresis-related relationship between that of the coil 20 generated magnetic field strength H (or the coil current I _is ) on the one hand and the magnetic induction B of the magnetizable component (field-generating component 18 and housing 16 ) And the thereby induced mechanical operative connection on the other hand, it is generally difficult and costly, the respective desired Remanenzmoment Mr _to set with sufficient accuracy.

In order to achieve a sufficient positioning accuracy with a low computational effort, a control in two steps is provided according to the invention, starting from an arbitrary operating point within the hysteresis diagram ( 2 ) The desired Remanenzmoment Mr _to adjust. This will be explained below with reference to 3 and 4 explained.

3 shows in a block diagram one of the door brake 10 associated control device 50 , This control device 50 controls a power source 52 which serves as a power supply device and which the coil 20 the door brake 10 ( 1 ) over the connecting lines 22 optionally energized. As from the in 3 Dashed line shown feedback path, a current control can be provided for setting the desired respective coil current. Alternatively, a voltage control is possible.

The control device 50 is a storage device 54 assigned, among other things, a first table T1 and a second table T2 are stored. The said door brake control device 50 is further with a higher level control device 56 connected to the motor vehicle.

The door brake control device 50 controls the power source 52 and thus the one through the coil 20 guided current in response to setpoint values of the holding torque, by the vehicle control device 56 be transmitted. The door brake control device 50 is capable of any operating points of the door brake 10 along and within the hysteresis loop 120 according to 2 to drive and track. For this purpose, the controller uses 50 in particular an inverse hysteresis model, in order to convert a desired value of the holding torque (or the magnetic induction) into a suitable manipulated variable (eg coil current) or to establish a linear relationship between the desired value and the manipulated variable. In particular, the activation of the respective operating point can take place on the basis of a so-called Preisach model. For example, this describes US Pat. No. 7,250,738 B1 a suitable for this Further development of the Preisach model. To the field-generating component 18 and the case 16 if necessary, demagnetize causes the controller 50 the power source 52 for generating an alternating current with decreasing intensity, as already explained above.

The models used, however, do not allow the setting of any remanence torque (ie holding torque with no current supplied coil) with the desired accuracy. Therefore, such is the vehicle control device 56 Prescribed remanence moment Mr _{should be set} in two steps.

The corresponding part of the door brake control device 50 The tax procedure implemented is in 4 shown. In a step S1, the door brake controller receives 50 from the vehicle controller 56 a setpoint of remanence Mr Mr _should . The door brake controller then initiates 50 in a step S2, the power source 52 ( 3 ) to reduce the coil current I _is at zero. This causes the door brake 10 a preliminary remanent magnetic induction of the field-producing component 18 and the housing 16 is set, which from the last actuated operating point of the door brake 10 results. This provisional remanent magnetic induction thus corresponds to a provisional remanence moment, but not necessarily the actual desired remanence moment Mr _soll .

Therefore, the door brake controller detects 50 a corresponding correction current I _CORR, in a step S3: _In response to the last set holding torque manure and the previously set coil current I corresponding to the last driven operating point of the door brake 10 correspond determines the door brake control device 50 from the in the storage device 54 stored first table T1 a value of a reference holding torque Mr _ref . This reference holding torque Mr _ref corresponds to the provisional remanence torque set as a result of the switching off of the coil current. In dependence on this value and on the desired value of the remanence torque Mr _, the door brake control device _{is to be} determined 50 from the stored table T2 the said correction current I _corr , for example a respective value of the polarity and the amplitude of the coil current to be set.

In a step S4 causes the door brake control device 50 the power source 52 for generating a current pulse according to the determined value I _corr . The duration of this current pulse can be fixed here. After generation of this current pulse, the coil current is zero again. As a result of the current pulse, the remanent magnetic induction of the field-producing component is 18 and the housing 16 from the previously set preliminary value (reference value) is now corrected to that value which corresponds to the desired remanence moment Mr _soll . In other words, the field-generating component 18 and the case 16 the door brake 10 now magnetized in such a way that when energized coil 20 a magnetic field at the location of the magnetorheological fluid 38 is generated, which _{is to} the desired Remanenzmoment Mr between said first element of the door brake 10 (Fastener 12 with the housing 16 and the field-generating component 18 ) and the second element (fastener 14 with the topflamelle 26 ) causes. The temporary generation of said current pulse thus causes a shift of the instantaneous operating point of the door brake 10 along the vertical axis of the hysteresis diagram according to 2 ,

It should also be noted with regard to the explained control method that, for example, steps S2 and S3 can also be reversed. It is only important that first the coil current I _is reduced to zero and that thereafter a correction current I _{corr is} generated for a short time in order to correct the provisionally set remanence torque Mr _ref to the desired value Mr _soll . As a result, the control can be based on two simple tables whose values have previously been determined empirically. In this context, it is also not mandatory that the control device 50 the reference value Mr _ref set in the meantime, but this reference value can directly form an input value for the said second table T2. The two tables T1 and T2 can thus also within the memory device 54 be linked together.

It should also be noted that a repeated repetition of step S4 can also be used for the remanence moment Mr of the door brake 10 to vary quasi-continuously.

Finally, to the illustrated embodiment, it should be noted that the control according to the invention is also suitable for other magnetorheological holding devices with two relatively movable elements, in particular for arrangements such as those mentioned in the introduction DE 10 2006 037 992 A1 are described.

10

door brake

12

fastener

14

fastener

16

casing

18

field generating component

20

Kitchen sink

21

group of coil wires

22 24

supply line

26

pot disk

28

Rotation angle sensor

29

camp

30

axis of rotation

32

bearings

34

sealing rotation degree

36

fixing screw

38

magnetorheological fluid

40

magnetic field line

50

control device the door brake

52

power source

54

memory device

56

control device of the vehicle

120

hysteresis loop

122

New curve

B

magnetic induction

H

magnetic field strength

I _corr

correction current

I _is

actual value of the coil current

M _is

actual value the holding moment

Mr _should

setpoint of the remanence moment

Mr. _ref

reference value of the remanence moment

T1

first table

T2

second table

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• - DE 10029227 A1 [0003]
• - DE 102006037992 A1 [0004, 0046]
• - US 7250738 B1 [0039]

Claims (14)

Method for setting a variable currentless active connection in a magnetorheological holding device ( 10 ), wherein the holding device comprises at least: - a first element ( 12 . 16 . 18 ) and a second element ( 14 . 26 ) which are movable relative to each other; A magnetizable component ( 16 . 18 ) with remanent properties; A magnetorheological medium ( 38 ), which is in the magnetic field of the magnetizable component when magnetized, and via which the two elements can be brought into operative connection; and - a coil ( 20 ) with an associated power supply ( 52 ) for generating an electric current in the coil to generate a magnetic field sufficient for magnetizing the magnetizable component; wherein, in a first step (S2), starting from a current operating point (M _ist , I _ist ) of the holding device, the coil current is reduced to zero in order to obtain a preliminary remanent magnetic induction of the magnetizable component ( 16 . 18 ); and wherein, in a subsequent second step (S4), a correction current (I _korr ) of the coil is temporarily adjusted and reduced to zero to set a desired remanent magnetic induction of the magnetizable component from the preliminary remanent magnetic induction such that a currentless operative connection between the first element ( 12 . 16 . 18 ) and the second element ( 14 . 26 ) is produced; wherein a reference value (Mr _ref ) representing the provisional residual magnetic induction set in the first step is determined in dependence on said current operating point from a first stored table (T1), and depending on the determined reference value and a setpoint value (Mr _soll ), which represents the desired magnetic induction, is determined from a second stored table (T2) of the correction current (I _korrc ) to be set temporarily in the second step (S3). Method according to claim 1, wherein the current working point of the holding device ( 10 ) on the one hand by a current coil current (I _ist ) or a current field strength of the current from the coil ( 20 Magnetic field generated (H), and on the other by a current magnetic induction (B) of the magnetizable component ( 16 . 18 ), a current magnetization of the magnetizable component, a currently effective between the two elements holding torque (M _is ) or a currently effective between the two elements holding power is set. Method according to one of the preceding claims, wherein the current operating point (M _is , I _is ) of the holding device ( 10 ) is determined by an inverse hysteresis model. Method according to one of the preceding claims, wherein the reference value (Mr _ref ) a value of the magnetic induction of the magnetizable component, a value of the magnetization of the magnetizable component, a value of the effective between the two Elemen th holding moment or a value of the effective between the two elements Holding power is. A method according to any one of the preceding claims, wherein the setpoint (Mr _soll ) is a value of the desired magnetic induction of the magnetizable component, a value of the desired magnetization of the magnetizable component, a value of the desired holding torque between the two elements, or a value of the desired between both elements effective holding force. Method according to one of the preceding claims, wherein the desired value (Mr _soll ) from a higher-level control device ( 56 ) is transmitted. Method according to one of the preceding claims, wherein in the second table (T2) values of the polarity, values of the amplitude and / or values of the time duration of the correction current (I _corr ) to be set are stored. Method according to one of the preceding claims, wherein the coil ( 20 ) and the magnetizable component ( 16 . 18 ) in such a way that at least one currentless state can be generated, in which the magnetizable component, after its magnetization, provides a magnetic field (H) which is used to maintain the operative connection between the first element ( 12 . 16 . 18 ) and the second element ( 14 . 26 ) with the help of the magnetorheological medium ( 38 ) is sufficient. Method according to claim 8, wherein the coil ( 20 ) and the magnetizable component ( 16 . 18 ) cooperate such that at least one further currentless state can be generated, in which the magnetizable component is again substantially demagnetized, whereby the operative connection between the first element and the second element can be canceled. Method according to one of the preceding claims, wherein the magnetizable component ( 16 . 18 ) by energizing the coil ( 20 ) is demagnetized with an alternating current of decreasing strength. Magnetorheological holding device ( 10 ) at least comprising: a first element ( 12 . 16 . 18 ) and a second element ( 14 . 26 ) which are movable relative to each other; A magnetizable component ( 16 . 18 ) with remanent properties; A magnetorheological medium ( 38 ), which is in the magnetic field of the magnetizable component when magnetized, and via which the two elements can be brought into operative connection; - a coil ( 20 ) with an associated power supply ( 52 ) for generating an electric current in the coil to generate a magnetic field sufficient for magnetizing the magnetizable component; A control device ( 50 ); and - a memory device which can be read out by the control device ( 54 ); the control device ( 50 ) is adapted to - in a first step (S2) starting from a current operating point (M _is , I _is ) of the holding device to reduce the coil current to zero in order to obtain a preliminary remanent magnetic induction of the magnetizable component ( 16 . 18 ), and - in a subsequent second step (S4), temporarily adjusting and reducing again a correction current (I _korr ) of the coil to set a desired remanent magnetic induction of the magnetizable component from the preliminary remanent magnetic induction so that an electroless active compound between the first element ( 12 . 16 . 18 ) and the second element ( 14 . 26 ) is produced; wherein in the memory device ( 54 ) a first table (T1) is stored, from which in dependence on the said current operating point a reference value (Mr _ref ) is read, which represents the preliminary remanent magnetic induction set in the first step, and wherein in the memory device ( 54 ), a second table (T2) is stored, from which in dependence on the read reference value and a setpoint (Mr _soll ), which represents the desired magnetic induction, the correction _{current to be} temporarily set in the second step (I _korr ) is read out. Holding device ( 10 ) according to claim 11, wherein the first element ( 12 . 16 . 18 ) and the second element ( 14 . 26 ) are mounted rotatably, pivotally or displaceably to each other. Holding device ( 10 ) according to claim 11 or 12, wherein the magnetisable component ( 16 . 18 ) is formed by the first element or the second element. A containment system comprising a retainer according to any one of claims 11 to 13, for a door or flap hinged to a structure fixed relative thereto, whereby either the first element or the second element (Fig. 14 . 26 ) moved at least indirectly with the door or the flap and wherein the respective other element ( 12 . 16 . 18 ) is attached to the fixed structure.