DE102010013597B3 - Method for controlling a drive system of an actuating element of a motor vehicle and corresponding drive system - Google Patents

Abstract

The invention relates to a drive system (1) for an actuating element (10) of a motor vehicle and a method for controlling the drive system (1), in which an electric motor (3) has a drive element (21) and a drive element (21) with the same via a transmission (17, 18) via a torsion spring (23) coupled output element (22) drives about a common axis of rotation (20). The torsion spring (23) transmits a torque acting on the drive element (21) to the output element (22) in both directions of rotation (R, R) and blocks a torque on the output side. Control electronics (25) are set up to store a current position value of the control element (10) determined on the basis of the motor speed (n) and / or the motor current (I) and the direction of rotation (R, R) if this is in one of the directions of rotation ( R, R) driven drive element (21) is stopped after an adjustment movement. When the adjusting element (10) moves again in the same or opposite direction, an increase in the motor speed (n) or an increase in the motor current (I) up to or at the moment of a non-positive coupling of the drive element (21) via the torsion spring (23) the output element (22) is detected and a correction value for compensating a position shift of the drive element (21) with respect to the stored position value is determined therefrom.

Description

The invention relates to methods for controlling a drive system of an actuating element of a motor vehicle, in which an electric motor drives a drive element via a gear and a driven element coupled thereto via a torsion spring about a common axis of rotation. It further refers to a drive system operating according to this method.

In a motor vehicle usually actuated by electronically controlled drive systems actuators (adjustment), in particular electric windows available. During a setting operation of such an actuating element, a desired end position must be approached precisely, for which purpose a precise knowledge of the setting position of the adjusting tool is required. The knowledge of the current parking position or derived therefrom variables, such as the positioning speed or the distance traveled, are also required for the safe detection of a pinch.

For the most accurate detection of the parking position of a window, it is for example from the DE 199 16 400 C1 known to provide a position and direction of rotation sensor. This consists essentially of a Hall sensor (Hall IC) with two offset at a distance or angle to each other arranged sensor surfaces and a multi-pole, for example, two- or four-pole ring magnet, which is arranged on the drive shaft of the electric motor. The Hall sensor detects a change in magnetic field due to a rotation of the fixedly connected to the drive shaft ring magnet and generates count pulses. These are evaluated together with information about the direction of rotation of the ring magnet and thus the electric motor by the counts are counted up or down depending on the direction of rotation of the drive and thus specify the respective position of the window.

Such a drive system comprises in addition to the drive or electric motor, a transmission gear, which transmits the torque of the electric motor, for example via a cable (cable window lifter) and a coupled with this and guided in a guide rail driver on the attached to this window, so that the actuator (Vehicle window) as a result of a control command along an adjustment path between a closed position and an open position adjustable (movable). In order to keep the actuator in virtually any position along the adjustment even when switched off (stopped) electric motor in each approached position, means for inhibiting the drive system are provided. For this purpose, for example, the transmission be designed to be self-locking, which is achieved in a commonly used worm gear by a corresponding tooth pitch of the external teeth of a worm wheel, which meshes with a shaft-fixed screw of the drive or motor shaft.

When running the drive system with a non-self-locking gear, it is out of WO 2007/014686 A1 known to couple at an adjusting device for a motor vehicle, a motor-side drive element and a control element-side output element via an effective manner of a wrap spring spring (wrap spring clutch). The torsion spring transmits an effective torque to the drive element in both directions of rotation to the output element and blocks - in both directions of rotation - a driven-side torque (wrap spring brake).

Although such a drive system with non-self-locking gear is characterized by a high degree of efficiency. However, even in such a drive system due to the system a certain mechanical play in the self-locking exists. This means that until reaching the inhibitory counterforce of the rotating or coil spring already due to the transmission ratio of the transmission, which is, for example 1:73, several partial revolutions of the motor armature or the motor shaft done before blocking a driven side torque occurs, for example a force is generated on the actuator.

While exact position detection of the actuating element and thus of the motor armature (motor shaft) is essential for ensuring the legal requirement with respect to anti-jamming protection, positional shifts occurring, in particular in the case of a so-called sleep mode, in which the Hall sensor normally used for position detection can occur. Sensor due to quiescent current requirements regularly in the idle state of the drive system or its electronics (control unit) is disconnected from the power supply or power supply, not reliably detected.

Even with a drive system with little existing game in the self-locking therefore has the disadvantage that even low mechanical forces from the outside, such as shaking the vehicle window, in the idle state of the drive system (control unit) a significant, non-measurable offset in the positioning of the system can result. As a result, under certain circumstances, the legal requirements regarding an anti-trap protection can not be ensured.

The invention is therefore based on the object to improve such a drive system with respect to the position accuracy or determination of the driven actuator.

This object is achieved by a method having the features of claims 1 and 2. The object is further achieved by a drive system with the features of claim 3. Advantageous embodiments and modifications of the invention will become apparent from the dependent claims and the following embodiments.

For this purpose, the drive system comprises an electric motor which drives a drive element which is rotatable about a rotation axis via a gear, in particular with high efficiency (greater than 50%). The motor-side connected drive element is coupled to an output element connected to the actuating element, wherein the drive element and the output element are preferably mounted coaxially behind one another via a torsion spring. The suitably acting as a wrap spring acts on a drive-side torque in both directions as a clutch (torsion spring or wrap spring clutch) for transmitting the torque via the output element to the actuator. In a driven-side torque, which is transmitted as a result of a force on the actuator and thus on the output element, the torsion spring as a brake (torsion spring or wrap spring brake) is effective and blocks the output side torque to prevent its transmission to the drive element as far as possible.

The drive system according to the invention also comprises an electronic control system, which is set up for the execution of the method according to the invention or one of its variants described below circuit and / or program technology, so that the inventive method is performed automatically. The control electronics is set up to store a current position value of the control element determined on the basis of the engine speed and / or the motor current and the direction of rotation when the drive element driven in one of the directions of rotation is stopped following an adjustment movement. Upon renewed adjustment movement of the actuating element in the same direction or in the opposite direction, an increase in the engine speed or an increase in the motor current up to or at the moment of a non-positive coupling of the drive element via the torsion spring with the output element is detected and therefrom a correction value for compensating a positional shift of the drive element relative to the stored position value determined.

In other words, suitable means are provided to determine each position value of the control element based on the engine speed and / or the motor current and the direction of rotation and to store the current position value when the drive element is stopped or stopped following an adjustment. In addition, means are provided for a renewed or subsequent adjusting movement of the actuating element in the same direction of rotation (rectification) and / or in the opposite direction of rotation (opposite direction) an increase in the engine speed (speed increase) or the motor current (current increase) up to and especially at the moment one (mechanical) adhesion within the drive system, d. H. starting from the drive element and via the torsion spring with the output element and ultimately beyond, in particular in a cable window lifter, to the traction or at the moment of frictional engagement with the vehicle disc bearing carrier to capture and evaluate the position compensation. From this speed increase or the motor current increase, the determination (determination) of a correction value to compensate for a position shift of the drive element relative to the stored position value and thus for position determination or correction of the control element takes place.

For speed or rotation detection of the control electronics associated with a Hall sensor, which cooperates with a non-rotatably connected to the motor shaft ring magnet. The Hall sensor can already be mounted on a circuit board (printed circuit board) of the control electronics. In order to determine the increase in current at the moment of the frictional connection, the motor current signal, which as a rule has already been detected and evaluated for other purposes, is used.

For the highest possible efficiency, the drive system has a non-self-locking worm gear with a worm rotatably fixed to the motor shaft and with a worm wheel meshing therewith. The worm wheel comprises in one piece or carries a housing which receives the drive element and the driven element and the torsion spring and coaxially mounted one behind the other. The torsion spring is frictionally engaged on the housing inner wall in the initial state under a certain spring bias and can be solved from there only by means of the drive element in both directions of rotation (coupling effect). As a result of a driven-side torque, the driven element expands the torsion spring coils with increasing torque increasingly and thereby braces the torsion spring against the housing inner wall frictionally (braking effect).

The torsion spring suitably has approximately at right angles to the inside, ie to the common Rotary axis towards bent spring ends, which rests (at least in a symmetrical initial state) with a defined angular play between stops of the drive element (drive stops) and stops of the output element (output stops). Preferably, a release angle is defined within the angular clearance between the respective spring end and the drive stop associated therewith. This release angle passes through the drive element as a result of a drive-side torque until the release of the torsion spring of the associated contact or friction surface.

During an adjustment movement of the actuating element in the rectification, the determination of the correction value results from the (mechanical) force increase of the drive and adjustment system within this solution angle. As a criterion within the increase in force, the system increases until the release of the torsion spring with the engine speed and then drops to the coupling with the output element, a position-determining extreme value is suitably used, for example, the maximum value of the speed increase. Also, the falling edge of the force increase can be used as a criterion for determining the correction value. Since, as is known, the force increase and the subsequent force drop are followed by a further extreme value in the form of a minimum, and the engine speed then quasi settles to a constant value, the position-determining position of this minimum can also be used to determine the correction value.

Analogously, in an adjusting movement of the adjusting element in rectification as a criterion at the moment of increase in force due to the system when releasing the torsion spring and possibly then increases until coupling with the output element of the motor current, suitably turn a position determining extreme value of the motor current (motor current signal), for example, the maximum value of the current increase, be used to determine the correction value from the (mechanical) force increase of the drive and adjustment system. The falling edge of the motor current profile can also be used as a criterion for determining the correction value.

During an adjusting movement of the adjusting element in the opposite direction, the determination of the second correction value is suitably carried out from the area of the double angular play which is passed by the drive element - depending on the direction of rotation - between one or the other drive stop and the respective opposite driven stop. For example, if the angular play taking into account the gear ratio of the transmission twelve times revolutions at the motor armature (motor shaft), it is recognized that the expected position value at the location of the measured speed increase or the detected motor current increase in the opposite direction by twelve quarter turns from the stored position value , The number of quarter-turn is to be regarded as parameterizable (+/-) offset in both directions.

An embodiment of the invention will be explained in more detail with reference to a drawing. Show:

1 a schematic representation of a window lift drive system of a motor vehicle,

2 in a partial sectional view of the drive system with an electric motor and with a worm gear and with a control electronics and a torsion spring clutch or brake in the gearbox,

3 the essential functional elements of the torsion spring brake / clutch with a via the rotating or coil spring coupled to a drive element output element in a symmetrical initial state,

4 in a representation according to 3 the functional elements (drive element, output element and torsion spring) in a force-locking coupling as a result of a driven-side torque,

5 in a representation according to 5 the alignment of the functional elements to each other after elimination of the output side torque,

6 in a representation according to 1 the frictional coupling between the functional elements in a drive-side torque to illustrate a renewed adjustment in the opposite direction,

7 in a current-speed-time diagram, the profile of the engine speed and the motor current in the drive system with an adjustment movement in the opposite direction with a speed increase and a current increase up to or at the moment of the adhesion coupling of the functional elements to determine a correction value,

8th in a diagram according to 7 the course of the engine speed and the motor current in the drive system with a pitch in rectification, and

9 in a perspective view of an embodiment of the trained as a wrap spring in spring 1 ,

Corresponding parts are provided in all figures with the same reference numerals.

In 1 schematically a window of a motor vehicle is shown, the drive system 1 one on a base plate 2 mounted electric motor (drive motor) 3 includes, via a transmission ( 2 ) a cable drum 4 drives around the several turns of a rope closed to a loop (cable) 5 are wound. The rope 5 is via rope pulleys 6 along a guide rail 7 led, on by means of the rope 5 a driver 8th with a lifting rail 9 for receiving a vehicle window 10 due to a corresponding control of the drive system 1 is moved. By means of the rope 5 Therefore, the adjusting force, ie, a drive-side torque of the electric motor 3 on the vehicle window 10 transferred, depending on the direction of rotation of the electric motor 3 along an adjustment path 11 between a closed position P _S and an open position P _{O can be} raised or lowered.

In 2 is the drive system 1 shown comparatively detailed. This includes the electric motor 3 with one in a motor or pole housing 12 and an associated transmission housing 13 rotatably mounted, wound motor armature (rotor) 14 and a stator formed of permanent magnets 15 , The electric motor 3 drives via its motor shaft (drive shaft) 16 a worm gear with a shaft-fixed screw 17 and with one in the gearbox 13 rotatably mounted worm wheel 18 at.

With the worm wheel 18 connected or mounted on this is a cylindrical or cup-like coupling or brake housing 19 in which a central axis of rotation 20 a drive element 21 and an output element 22 via a twist or wrap spring 23 are stored coaxially one behind the other. An embodiment of the wrap 23 with a number of spring coils 24 and inwardly radially angled spring ends 24a and 24b is in 8th shown in perspective. It can be seen that the two spring ends 24a and 24b in the axial direction along the axis of rotation 20 around the thickness and number of spring coils 24 spaced apart from each other.

The drive system 1 further includes an electronics or electronics module 25 with a component-mounted printed circuit board (electronic board) 26 with it on the motor shaft 16 facing plate end mounted Hall sensor 27 in an electronics housing 28 , This is a rotationally fixed on the motor shaft 16 arranged ring magnet 29 as small as possible axially spaced. The Hall sensor 27 detects itself with rotating ring magnet 29 changing magnetic field. This results in dependence on the number of magnetic poles of the ring magnet 29 to a number of countable Hall pulses used to determine the engine speed n and the direction of rotation of the electric motor 3 from the electronics 25 be evaluated. To determine the direction of rotation, the Hall sensor 27 in a suitable, not shown, two mutually spaced sensor surfaces, so that from the sequence of the temporally offset generated by the sensor surfaces Zählimpulsfolgen the respective direction of rotation is identified.

Via a connection or electronic plug 30 and housing internal motor contacts 31 with brush holders 32 are connected, via which the motor current I _M to a commutator 33 the engine anchor 14 is transferred, the energy or power supply of the electric motor takes place 3 from a vehicle battery (not shown). About the connector 30 can also control signals of the drive system 1 be coupled and / or decoupled.

The 2 shows in the area between the ring magnet 29 and the snail 17 of the worm gear as a ball bearing 35 trained depository. The ball bearing 35 is located in the gearbox housing 13 , The ball bearing 35 consists of a shaft-fixed bearing inner ring 35a and a housing-fixed bearing outer ring 35b as well as from a number of balls 35c between the bearing rings 35a . 35b , Instead of bullets 35c Rollers can also be provided. The ball bearing 35 can thus be designed as a roller or needle ball bearings.

The bearing inner ring 35a is on the bearing shaft 16 in an enlarged wave range shaft-mounted, for example, pressed or shrunk, the outer diameter is greater than the shaft diameter d _{1 of} the remaining wave ranges of the armature shaft 16 , The bearing outer ring 35b lies to the radial storage in a in the transmission housing 13 molded bearing seat. This bearing seat is on average L-shaped, so that the ball bearing 35 on the gearbox 17 . 18 facing side to form a passage opening for the armature shaft 16 in the gearbox 13 is practically embedded. An axial fixation of the bearing outer ring 35b of the ball bearing 35 on the other bearing side is by means of a collar-like flange of housing material of the gear housing 13 produced. This beading engages behind the gearbox 17 . 18 opposite bearing side of the ball bearing 35 the bearing outer ring 35b at least partially.

The armature or drive shaft 16 is in the shaft direction in front of the engine anchor 14 and behind the gearbox 17 . 18 in storage areas 36 respectively. 37 stored. These bearings 36 . 37 can also as Fixed bearing (ball bearings) or be designed as plain bearings in the form of spherical or cylindrical bearings. The engine-side bearing 36 is from one of the engine case 12 formed bearing plate closed to the outside.

The 3 to 6 show in a simplified, schematic representation of the functional elements, ie the drive element 21 and the output element 22 as well as the torsion spring 23 in a symmetrical, neutral initial state. The torsion spring 23 lies in a manner not shown on the cylindrical housing inner wall of the clutch or brake housing 19 under some bias already frictionally. The spring ends 24a . 24b the torsion spring 23 lie between the drive element 21 and the output element 22 symmetrically. It is between the respective spring end 24a . 24b and these facing stops (drive stops) 21a respectively. 21b of the drive element 21 given a defined angular clearance (angular distance) α ₁ . Analog is between the spring ends 24a . 24b and these facing attacks 22a respectively. 22b (Output stops) of the output element 22 a defined angular clearance (angular distance) α _{2 is} present.

3 also illustrates a release angle γ ₁ , that of the drive element 21 in each of the two directions of rotation R ₁ , R ₂ to be overcome path (angle) until complete detachment of the torsion spring 23 or their spring coils 24 from the housing inner wall of the housing (coupling housing) 19 represents. Analogously, the in 3 illustrated braking angle γ ₂ from the output element 22 as a result of a driven-side torque in both directions of rotation R ₁ , R ₂ to be overcome way (mechanical clearance) until complete blockage of the torsion spring 23 by a corresponding frictional engagement with the housing (brake housing) 19 , In that the drive element 21 and the output element 22 on opposite sides of the inwardly angled spring ends 24a . 24b the torsion spring 23 are arranged, this acts on a drive-side torque, ie from the drive side to the output side as a clutch, as a result of a contraction of the spring coils 24 through the drive element 21 the outer diameter of the torsion spring 23 is reduced. At a driven side torque, ie from the output side to the drive side, the torsion spring acts as a brake by the outer diameter is increased.

4 illustrates the state and relative position of the functional elements 21 to 23 as a result of a driven-side torque in the direction of rotation R ₁ . Until the blocking of the output side rotational movement due to a complete frictional engagement of the torsion spring 23 with the housing (brake housing) 19 goes through the output element 22 and thus its output stop 22a a resulting from the angular play α ₂ and the braking angle γ ₂ angle β, with β = α ₂ + γ ₂ . Due to the consequent frictional connection between the functional elements 21 to 23 is the overall system starting from the vehicle window 10 about the driver 8th and the rope 5 as well as via the output element 22 up to the drive element 21 mechanically tense.

Is the output side torque canceled and thus no longer effective, the system relaxes, as in 5 is illustrated. In this case, a return movement takes place only of the output element 22 and the torsion spring 23 , but not also the drive element 21 at least not to the same extent. In still effective output side torque has in the course of the tension of the overall system, however, the drive element 21 at least slightly adjusted in the direction of rotation R ₁ , wherein this adjusting movement at no longer effective output-side torque to a complete return movement of the drive element 21 leads. This position shift or adjustment of the drive element 21 However, this is already due to the coupling via the worm gear 17 . 18 on the motor shaft 16 and thus also on the ring magnet 29 been transferred, which has accordingly changed its angular position accordingly.

Is now the electronics and thus the Hall sensor 27 in this situation in so-called sleep mode, in which previously the current position value of the ring magnet 29 and thus the current adjustment position of the vehicle window 10 in electronics 25 deposited (saved), so is correct when re-powering the Hall sensor 27 (wake up) the stored position value is no longer with the actual position of the drive element 21 - like this current position the in 4 illustrated position of the drive element 1 in the state of sleep mode had been - no longer match. This means that in a renewed adjustment in the same direction, for example, the direction of rotation R ₂ , the drive element 21 initially until the adhesion with the output element 22 in the 5 illustrated angle plays δ ₁ and δ ₂ passes through.

This, due only to an undesirable output-side torque caused mechanical play between the functional elements 21 to 23 leads in a renewed adjustment in the same direction of rotation R ₂ (rectification) to a speed increase and a motor current increase of the electric motor 3 : The reason for this is that the adhesion between the functional elements that existed at the time of sleep mode 21 to 23 at a new wake up of the electronics 25 and of the Hall sensor 27 no longer exists. This is the driving torque of the functional elements 21 to 23 in comparison to the power transmission state counter-torque is comparatively low, resulting in the speed increase of the electric motor 3 leads.

The speed increase as well as a significant increase in current at the moment of adhesion are in 7 for a renewed adjustment movement in the opposite direction R ₁ and in 8th for a renewed adjustment in rectification R ₂ illustrated. It shows 7 in a current-speed-time diagram, the speed curve n _k (t) without torsion spring bearing in comparison to a speed curve n (t) with torsion spring play. The associated motor current waveforms I _Mk (t) and I _M (t) in such an adjustment in the opposite direction R ₁ without or with torsion spring are shown below the speed curves n _k (t) and n (t). At times t ₁ (without torsion spring play) and t ₂ (with torsion spring play), following a speed increase n _max, a clear speed _minimum n _min at traction occurs. In the motor current signals I _Mk (t) and I _M (t) is shown at these times t ₁ (without torsion game) and t ₂ (with torsion game) a corresponding increase in current (increase in force). From the time t ₁ or t ₂ , the speed curve behaves equal to the one without previous output-side torque in sleep mode with continuing existing adhesion between the functional parts 21 to 23 ,

Recognizable at a renewed adjustment in the case of a previously generated in sleep mode output torque initially a relatively steep speed increase (speed increase) up to a maximum value n _max (t ₂ ) and from there along a falling speed edge up to a minimum engine speed n _min ( t ₄ ). From there, this speed curve n _k (t) or n (t) goes into the steady state in accordance with the normal speed curve without previous output torque in sleep mode.

Analogously, at a renewed adjustment in the case of a previously produced in the screen mode output torque at time t _1, a short time high motor current I _{M can be seen} , which is caused by a release of the mechanical system tensions, in particular by releasing the frictional engagement of the torsion spring. Subsequently, the motor current I _M drops, in order to rise comparatively slightly up to a maximum value I _max (t ₃ ) or I _max (t ₄ ) up to the time t ₃ . From there, the motor current profile I _M k (t) or I _M (t) in the steady state in accordance with the normal motor current waveform over.

In 7 In addition, the disk positions P without a torsion spring play and P _k with a torsion spring play as well as the courses of the position counter P without a torsion spring play or C _k with a torsion spring play are illustrated. The slice positions P, P _k are synonymous with the actuator positions.

8th shows in a diagram according to 7 the conditions in a renewed adjustment in rectification. Here, based on the speed curve n (t) no significant speed increase can be seen, but rather an asymptotic course up to the rated speed. Analogously, a rather asymptotic curve up to the nominal current is also recognizable in the current profile of the motor current I _M (t). Nevertheless, at t ₁ in the case of the torsion spring system, a corresponding fall in rotational speed or increase in current at frictional engagement is recognizable, which in turn is used to compensate the position of the adjusting element or disc by determining a corresponding correction value.

To determine the correction value for compensating the position shift caused in the sleep mode, the times t ₃ , t _{4 of} the _minimum speed n _{min of} the speed increase or of the current increase I _max (opposite direction, 7 ) or t ₁ (rectification, 8th ). Alternatively, it is also possible to use the speed change Δn in the region or along the speed increase of the speed increase as a measure of the correction value. A corresponding correction value can thus be determined from the _maximum speed n _max , the _minimum speed n _min and / or the speed change during the speed increase. Also, the speed drop along the falling edge of the speed increase can be used. Similarly, the current increase or decrease up to or from the maximum value I _{max can be used} to determine the respective correction value. Since the angular play α ₁ and α _{2 are} known in reverse rotation direction R ₁ or can also be measured, for example, at runtime, this is defined by the relationship 2 (α ₁ + α ₂ ).

If the angular play α ₁ + α _{2 is,} for example, 3.7 °, and is the transmission ratio of the worm gear 17 . 18 determined by 1:73, the total angular play 2 · (α ₁ + α ₂ ) running in the opposite direction leads to approximately twelve quarter turns of the motor armature 14 , This value is then the maximum correction value. An intermediate value, ie an angular play smaller than 2 · (α ₁ + α ₂ ) is then again by the in the 7 and 8th illustrated speed increase or the current increase of the motor current I _M determined.

LIST OF REFERENCE NUMBERS

1

drive system

2

Basic / supporting plate

3

electric motor

4

cable drum

5

Cable / Loop

6

cable pulley

7

guide rail

8th

takeaway

9

lift rail

10

vehicle window

11

adjustment

12

Engine / pole housing

13

gearbox

14

Motor armature / rotor

15

Permanent magnets / stator

16

Engine / drive shaft

17

slug

18

worm

19

Clutch / brake housing

20

axis of rotation

21

driving element

21a, b

Stop of the drive element

22

output element

22a, b

Stop of the drive element

23

Turn / wrap

24

spring coil

24a, b

spring end

25

Control / electronics

26

PCB / electronic board

27

Hall sensor

28

electronics housing

29

ring magnet

30

Electronics / connectors

31

motor Contact

32

brush carrier

33

commutator

35

ball-bearing

35a

Bearing inner ring

35b

Bearing outer ring

35c

Bullet

36

motor-side bearing

37

Gearbox side bearing

n

Engine speed

I _M

motor current

C

counter position

P

Stellelement- / wheel position

P _S

closed position

P _o

open position

R _1,2

direction of rotation

Claims (10)

Method for controlling a drive system ( 1 ) of an actuating element ( 10 ) of a motor vehicle, in particular a window regulator, in which an electric motor ( 3 ) via a transmission ( 17 . 18 ) a drive element ( 21 ) and one with this via a torsion spring ( 23 ) coupled output element ( 22 ) about a common axis of rotation ( 20 ), wherein the torsion spring ( 23 ) in both directions of rotation (R ₁ , R ₂ ) on the drive element ( 21 ) acting torque to the output element ( 22 ) transmits and blocks a driven-side torque, - wherein a control electronics ( 25 ) a based on the engine speed (n) and / or the motor current (I _M ) and the direction of rotation (R ₁ , R ₂ ) determined current position value of the actuating element ( 10 ) stores when in one of the rotational direction (R ₁ , R ₂ ) driven drive element ( 21 ) is stopped after an adjustment movement, and - wherein upon renewed adjustment movement of the actuating element ( 10 ) in the same direction of rotation (rectification) an increase in the engine speed (n) or the motor current (I _M ) to the non-positive coupling of the drive element ( 21 ) via the torsion spring ( 23 ) with the output element ( 22 ) and from this a correction value for compensating a positional shift of the drive element ( 21 ) is determined relative to the stored position value. Method for controlling a drive system ( 1 ) of an actuating element ( 10 ) of a motor vehicle, in particular a window regulator, in which an electric motor ( 3 ) via a transmission ( 17 . 18 ) a drive element ( 21 ) and one with this via a torsion spring ( 23 ) coupled output element ( 22 ) about a common axis of rotation ( 20 ), wherein the torsion spring ( 23 ) in both directions of rotation (R ₁ , R ₂ ) on the drive element ( 21 ) acting torque to the output element ( 22 ) transmits and blocks a driven-side torque, - wherein a control electronics ( 25 ) a based on the engine speed (n) and / or the motor current (I _M ) and the direction of rotation (R ₁ , R ₂ ) determined current position value of the actuating element ( 10 ) stores when in one of the rotational direction (R ₁ , R ₂ ) driven drive element ( 21 ) is stopped after an adjustment movement, and - wherein upon renewed adjustment movement of the actuating element ( 10 ) In the opposite direction of rotation (opposite direction) an increase in the engine speed (n) or the motor current (I _M ) to the positive coupling of the drive element ( 21 ) with the output element ( 22 ) and based on the current angular distance (α ₁ , α ₂ ) between the drive element ( 21 ) and the output element ( 22 ) a correction value for the synchronization of the current position value with the actual position of the actuating element ( 10 ) is determined. Drive system ( 1 ) for an actuator ( 10 ) of a motor vehicle, in particular window regulator control, with an electric motor ( 3 ), which has a transmission ( 17 . 18 ) about a rotation axis ( 20 ) rotatable drive element ( 21 ), with one around the axis of rotation ( 20 ) rotatable output element ( 22 ), with a drive element ( 21 ) and the output element ( 22 ) coupling torsion spring ( 23 ), which in both directions of rotation (R ₁ , R ₂ ) on the drive element ( 21 ) acting torque to the output element ( 22 ) and a driven-side torque blocks, and with a control electronics ( 25 ), which is set up, - each position value of the actuating element ( 10 ) based on the engine speed (s) and / or the motor current (I _M ) and the direction of rotation (R ₁ , R ₂ ) and to store the current position value when the drive element ( 21 ) stops after an adjusting movement, and - in a subsequent adjusting movement of the actuating element ( 10 ) from an increase in the engine speed (n) or the motor current (I _M ) to the non-positive coupling of the drive element ( 21 ) via the torsion spring ( 23 ) with the output element ( 22 ) a correction value for compensating a positional shift of the drive element ( 21 ) relative to the stored position value. Drive system ( 1 ) according to claim 3, with one of the control electronics ( 25 ) associated Hall sensor ( 27 ), which can be used for speed or direction detection with one with the motor shaft ( 16 ) non-rotatably connected ring magnets ( 29 ) cooperates. Drive system ( 1 ) according to claim 3 or 4, with a non-self-locking worm gear ( 17 . 18 ) with one with the motor shaft ( 16 ) non-rotatable screw ( 17 ) and with a meshing with this worm wheel ( 18 ), which is a driving element ( 21 ) and the output element ( 22 ) as well as the torsion spring ( 23 ) receiving housing ( 19 ), on whose housing inner wall the torsion spring ( 23 ) frictionally and by means of the drive element ( 21 ) releasably applied. Drive system ( 1 ) according to one of claims 3 to 5, wherein the torsion spring ( 23 ) angled spring ends ( 24a . 24b ) with defined angular play (α ₁ , α ₂ ) between stops ( 21a . 21b ) of the drive element ( 21 ) and attacks ( 22a . 22b ) of the output element ( 22 ) einliegen. Drive system ( 1 ) according to claim 6, wherein within the angular play (α ₁ , α ₂ ) between the respective spring end ( 24a . 24b ) and the stop facing it ( 21a . 21b ) of the drive element ( 21 ) a release angle (γ ₁ ) is defined, which the drive element ( 21 ) due to a drive-side torque until the release of the torsion spring ( 23 ) goes through. Drive system ( 1 ) according to claim 6 or 7, wherein within the angular clearance (α ₁ , α ₂ ) between the respective spring end ( 24a . 24b ) and the stop facing it ( 22a . 22b ) of the output element ( 22 ) a braking angle (γ ₂ ) is defined, the output element ( 22 ) as a result of an output-side torque to the blocking of the torsion spring ( 23 ) goes through. Drive system ( 1 ) according to claim 7 or 8, wherein during an adjusting movement of the actuating element ( 10 ) in rectification of the correction value from the change in rotational speed or motor current change representing the change in force and / or from an extreme value (n _max , n _min , l _max ) is determined. Drive system ( 1 ) according to one of the preceding claims, wherein during an adjusting movement of the actuating element ( 10 ) in the opposite direction of the correction value on the basis of the force change representing speed change or motor current change and / or their extreme values (n _max , m _min , l _max ) from that of the drive element ( 21 ) traversed angular play (α ₁ , α ₂ ) between the attacks ( 21a . 21b . 22a . 22b ) of the drive element ( 21 ) and the output element ( 22 ) is determined.

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