DE102005034034A1 - Method and device for detecting an obstacle in the opening region of a movable adjusting element - Google Patents

Abstract

The method according to the invention for recognizing an object (25) in the opening area (9) of a movable adjusting element (2, 21), in which at least a first (14) and a second electrical signal (15) are present, both signals (14, 15) are dependent on a property of at least part of the opening area (9), characterized in that, depending on a comparison of the course of the first electrical signal (14) with that of the second electrical signal (15) on an object (25) in the Opening area (9) is closed. DOLLAR A The method according to the invention and the device according to the invention advantageously allow anti-trapping protection to be implemented, in particular in the case of adjusting elements (2, 21) of motor vehicles (1) which are moved by an electric motor.

Description

object The present invention is a method and an apparatus for detecting an object in the opening region of a movable Adjustment element, in particular during a closing or opening of the Adjustment element. In particular, the inventive method and the device according to the invention for monitoring the closing process of movable adjusting elements in motor vehicles, such as of electrically closing Windows, sunroofs, doors, Cabriolet covers, tailgates and / or trunk lids, for Use come. Such a system is also known as a "anti-trap system".

In Motor vehicles take the number of electromotive moving components steadily too. In particular, it is known, side windows, sliding roofs, side doors, sliding doors, tailgates, Trunk lid, hoods or convertible tops electric motor to open and close. An electromotive drive moves the adjusting elements from a closed to an open position and vice versa. While the movement of the components can be a collision of the adjustment with an object (eg when opening a tailgate) or a pinching of an object in the adjustment or between Adjustment element and another component (eg when closing a Side window or a tailgate) occur. To such situations To avoid or be able to recognize in time, are safety systems been proposed that such a pinching or collision case detect. Such security systems can sometimes also countermeasures initiate, for example, when closing a tailgate: the immediate Stopping the closing movement and / or initiating an opening operation.

Such On the one hand, security systems comprise so-called "indirect" systems, the one possible Collision or a possible Pinching over changing Characteristics of the electromotive drive (eg via the evaluation of the torque or the power, current or voltage consumption). A deviation of the course of the measured characteristic with a Reference history is here as possible Collision or Einklemmfall interpreted, whereupon the traversing over a interrupted the electric motor associated control electronics becomes.

Farther are known "direct" security systems the above separately from the drive arranged sensors that detect an obstacle can, feature. Here are on the one hand contactless working direct systems with proximity sensors (such as capacitive or inductive sensors) or those in which a transmission path is interrupted (for example, a light or sound or Ultrasonic barrier). Furthermore, there are touching direct systems (Such as a corresponding switching strip) known, the only when the object is in contact with the closing edge and the body or the door frame trigger.

From the DE 102 48 761 A1 as well as the DE 102 48 762 A1 Pinch protection systems for hoods of a convertible are known in which a plurality of capacitive sensors are arranged in the critical region of the top movement range. The sensors monitor the surrounding dielectric (air) for change and are connected to the drive via evaluation electronics. If an object now approaches a sensor, the change in the capacitance of the dielectric is detected and the drive is stopped when a certain threshold value (switching point) is exceeded. This threshold, which must be readjusted automatically with respect to changing environmental conditions, represents a reference value, which is compared with a currently measured value. However, this system has the disadvantage that always a transmitter must be provided, which allows storage and readjustment of the threshold. In particular, the change in the dielectric constant of the environment must be taken into account by the readjustment of the threshold value, so that when this constant is changed (for example, as a function of the air humidity), the threshold value is adapted accordingly.

Of these, Based on the invention, the object with reference at least partially known in the art to solve. In particular, a method and an apparatus for detecting an object in the opening area to propose a movable adjustment, which is independent of changing Environmental conditions reliable and quickly an object in the opening area can recognize.

These Task is solved by a method having the features of claim 1, as well as a device with the features of claim 12. Advantageous developments are the subject of each dependent formulated claims.

The inventive method for detecting an object in the opening region of a movable adjusting element based on the fact that at least a first and a second electrical signal is present, both depending on a Property are at least part of the opening area. According to the invention, an object in the opening region is closed in dependence on a comparison of the course of the first electrical signal with that of the second electrical signal.

Under a movable adjusting element is in particular a side window, a sunroof, a side door, a sliding door, a tailgate, a trunk lid, a hood or a Cover of a motor vehicle to understand, each electric motor are movable. The opening area includes in particular the area through which the adjusting element when proceeding from an open moved to a closed position and vice versa. In case of a Side window of a motor vehicle, this would thus be the area through the window edge during of closing of the window moves. In a tailgate of a motor vehicle this is the opening area especially around the area which is between the open Tailgate and the closed tailgate is located. This includes the opening area in a partially open Position when opening Also, the area between the partially open position and the fully open Position of the tailgate is located. With subject in particular also things, body parts of Living things and the like meant.

According to the invention the currently measured waveforms, for example, checks for synchronicity. This can by comparing the present at a given time Gradients of gradients respectively. For this purpose, it is particularly advantageous if the slope is calculated from at least two measured values of the signal curve. In case of a deviation of the slope of the course of the first electrical Signal for the slope of the course of the second electrical signal can on the presence an object in the opening area getting closed. Furthermore, the comparison of the courses of the electrical signals also a comparison of the direct readings of the electrical signals, if necessary for noise suppression in time averaged, understood.

Of the Comparison of the two courses of the first and second electrical signals has the advantage that a reference value determination for drive the United invention no longer mandatory. Environmental changes do not have to more through appropriate measures considered be, since in particular with similarly trained sensors, which the first and second electrical signals provide the signals in case of a change change the environmental conditions similarly. So for example, has a changed one Although humidity on the absolute values of the courses of the first and second electrical signal influence, while being relative none on both courses significant change is to be determined and so when comparing the two gradients automatically the amended Environmental conditions are taken into account.

• – eine elektrische Kapazität und
• – eine elektrische Induktivität.

The above process is then particularly cost effective and feasible under many weather conditions if the property comprises at least one of the following electrical parameters:

• - an electrical capacity and
• - an electrical inductance.

These electrical quantities can by means of simply constructed sensors with high repeat accuracy and considerable speed.

According to one Another embodiment of the method according to the invention is a collision signal generated, by which it can be seen whether an object in the opening area is present.

The Collision signal allows data transmission in a simple manner to other components, such as a control device, which By means of the collision signal it is possible to detect whether an object is in the opening area present or not and can respond accordingly.

According to one further advantageous embodiment of the method according to the invention The course of the electrical signals each comprise a plurality of measured values, wherein the comparison of the course of the electric Signals comparing a first value of the first electrical Comprises a signal and a second value of the second electrical signal, wherein the values each comprise a time associated with measured values.

Especially is it possible according to the invention, the respectively current measured values of the first electrical signal and of the second electrical signal to compare.

According to one further advantageous embodiment of the method according to the invention The course of the electrical signals each comprise a plurality of measured values, wherein the comparison of the course of the electric Signals comparing a first value of the first electrical Comprises a signal and a second value of the second electrical signal, the values being assignable to at least two points in time Measurements include.

Thus, it is possible, in particular, to average the measured values over a preferably short period of time (limited by a first and a second instant), in order thus to determine the actual measurement attenuate noise. This is particularly advantageous when strongly noisy electrical signals are present. Furthermore, it is also possible to determine a currently applied slope of the course of the electrical signals and to determine this, for example, based on two or more measured values, to which a corresponding function is adapted.

Advantageous is also, if necessary, that for comparison a current average considered the first and second electrical signal becomes. Below the current value is here in particular an averaged Value to understand or a smoothed value, in which the influence of the noise was reduced as much as possible. Especially can here usual smoothing methods to the waveforms of the first and second electrical signals.

According to one further advantageous embodiment of the method according to the invention For comparison, the slope of the course of the first and the considered second electrical signal.

One Penetration of an object into the sensitive area of a capacitive and / or inductive sensor leads to a change the capacity or inductance and at the same time to a change the waveform in the form of a jump. The height of this jump depends in particular on the amount of conductive, dielectric and / or permeable material that is sensitive Area stops. The size of the jump and thus the associated size of the slope change is the speed and / or size of the entering object dependent. Based on the slope difference (the two courses of the first electric Signal and the second electrical signal) is more advantageous The danger of pinching an object in the opening area the locking device to recognize quickly.

According to one further advantageous embodiment of the method according to the invention the collision signal then signals an object in the opening area, when the absolute value of the difference of the compared signals one exceeds specified limit.

So can be easily defined when a deviation of the both courses the first electrical signal and the second electrical signal as penetration of an object in the opening region of the closure device to interpret. Irrelevant disturbances can be masked out in this way become.

According to one further advantageous embodiment of a method according to the invention the collision signal comprises a binary signal.

This is called in particular, that the collision signal exclusively to It can be seen whether there is an obstacle in the opening area, ie thus the risk of pinching the object during a closing or opening movement of the locking mechanism is given, or whether the opening area is free of obstacles.

Then, when the collision signal signals an object in the opening area, especially the closing movement the movable adjusting stopped or inverted. has the collision signal indicates that an object is in the opening area the movable adjusting element is located, can so in an advantageous manner a pinching of an object in the movable adjusting element or between a movable adjusting element and a fixed element avoided become.

• – Wahrscheinlichkeit eines vorliegenden Gegenstandes im Öffnungsbereich;
• – Zuordnung des Gegenstandes zu einem Messfühler;
• – Eindringgeschwindigkeit des Gegenstandes.

According to a further advantageous embodiment of the method according to the invention, the collision signal comprises at least one of the following information:

• - probability of a present object in the opening area;
• - Assignment of the object to a sensor;
• - Penetration speed of the object.

Based this information of the collision signal can be decided how to proceed further. For example, depending on the probability a present article in the opening area the closing or opening movement in different dimensions be slowed down. Likewise, the direction that makes up the object approaches, be identified and possibly checked with further monitoring means. The penetration rate leaves based on the change determine the slope of one of the electrical signals, so too appropriate, predetermined, different collision avoidance strategies here can be used.

According to one further advantageous embodiment of the method according to the invention the first electrical signal detects a property in a first one sensitive area and the second electrical signal in one property in a second sensitive area, the sensitive areas being one another overlap at least in a subarea.

The overlap of the sensitive areas creates a higher degree of process reliability, since the sensors and in particular their sensitive areas have a certain degree of change due to the environmental influences Subject to fluctuation. Thus, a sufficiently large overlap region, at least in a partial region of the sensitive regions, leads to the fact that even if the sensitive regions become smaller due to, for example, environmental influences, it is still ensured that the entire adjusting element is monitored during an opening or closing movement. In particular, it is also possible against this background that the overlapping partial area is chosen to be relatively large. Furthermore, sensors can thus be advantageously formed on two sides of an axis of the adjusting element, for example on both sides of a longitudinal axis of a boot lid or tailgate. In this way, it can be determined from which side of the adjustment element an object penetrates into the opening area.

According to one Another aspect of the invention is an apparatus for detecting an object in the opening area proposed a movable adjusting element, which at least a first sensor and a second sensor includes, wherein the first sensor a first electrical signal and the second sensor generates second electrical signal. The electrical signals are dependent a property of at least a part of the opening area. According to the invention is a Comparative unit formed depending on a comparison the course of the first electrical signal with the course of the second electrical signal provides a collision signal, based It can be seen whether an object is present in the opening area.

The inventive device In particular, in / on motor vehicles such as passenger cars, Lorries or vans are used. Especially can with the device according to the invention The following movable adjustment elements are also monitored: window panes, Convertible tops, sliding doors, tailgates, Trunk lid, sunroofs, Doors and / or Bonnets. All Adjustment elements can electrically operated become. For this purpose, the adjusting elements by means of an electric drive moved, so the actuation to facilitate or enable this adjustment.

The inventive device allows easy monitoring of these adjustment elements, to pinching an object in the adjustment during the Closing or an initiation of the object to prevent the adjustment when opening. These Device is particularly suitable, an inventively described Perform procedure.

• – Berühren des Sensors durch einen Gegenstand und
• – Annäherung eines Gegenstandes an den Sensor.

According to an advantageous development of the device according to the invention, the sensors comprise sensors which detect at least one of the following processes:

• - Touching the sensor through an object and
• - Approach of an object to the sensor.

Such Sensors are particularly suitable, pinching an object to effectively prevent in the adjustment. Especially preferred Here is the use of sensors that approximate a Detect object to the sensor. This prevents in an advantageous manner Way pinching objects in the adjustment at a time when the damage to the object or even a violation of a relevant person is still effective can be prevented.

• – einen kapazitiven Sensor und
• – einen induktiven Sensor.

According to a further advantageous embodiment of the device according to the invention, the measuring sensors comprise at least one of the following sensors:

• - a capacitive sensor and
• - an inductive sensor.

capacitive and inductive sensors have in a particularly advantageous manner as reliable contact- and / or proximity sensors exposed. These sensors are easy to implement and to operate in a simple manner. In particular, these sensors have Advantages in comparison, for example, to optical sensors, as a Comparison of the course of electrical signals, which is a capacitive and / or inductive sensor, is possible in a simple manner, so that advantageously a quick pinching or danger a pinching is registered and countermeasures such as stopping the closing movement or an inversion of the closing or opening movement are brought about can.

• – eine elektrische Kapazität und
• – eine elektrische Induktivität.

A "property of the opening area" in the sense of the present invention is understood in particular to mean a property which comprises at least one of the following electrical variables:

• - an electrical capacity and
• - an electrical inductance.

If the electrical capacitance is considered, there may in particular be a capacitive sensor which is sensitive to the approach or contact of an object. Such a capacitive sensor comprises an electrode which is part of a capacitor whose further electrode is given by the approaching object. The approaching object is thus understood as an "electrode lying on electrical ground." The capacitance of this capacitor depends on Distance d between the object and the electrode. In particular, there is an inversely proportional relationship between distance and capacitance. The capacitance of this capacitor can be measured in various ways, in particular by forming a resonant circuit in which the capacitor is integrated, and determining the resonant frequency of this resonant circuit; or via the use of a reference capacitor whose charging or discharging time is determined.

in the Trap of surveillance an electrical inductance, is an inductive sensor, which is based on that the inductance a coil in dependence of, for example, the magnetic permeability changes. Becomes an object with a magnetic permeability in the sensitive area a coil, in particular a surface coil, brought so changes the inductance the coil. The changed inductance the coil can be determined in particular by means of a resonant circuit be because the coil as part of a resonant circuit whose frequency influenced. In particular, you can So an evaluation unit with appropriate components (such for example, an electrical resistance and an electrical Capacity) be educated. More options, the inductance To determine this coil are possible according to the invention.

in the Regard to the comparison unit may be advantageous, if this is suitable, from each of a plurality of measured values comprehensive electrical signals have a first value of the first electrical Signal and a second value of the second electrical signal to compare with each other, the values each assignable to a time Measurements include.

For this In particular, the comparison unit comprises comparators which have a Comparison of the two signals can do together. Especially is under "one Time assignable readings " each current measured values of the electrical signals with each other be compared.

advantageously, the comparison unit is also suitable, from the respective one plurality of measured values comprising electrical signals a first value of the first electrical signal and a second value of the second electrical signal to each other, taking the values each comprise at least two times assignable measured values.

in this connection Values are formed which comprise several measured values. That means, for example, that an average of several, preferably close to each other, Measured values is formed, for example, a noise of the first and / or the second electrical signal. This can in particular not just linear smoothing be made, but usual attenuation method come into use. Furthermore, it is possible from several points in time assignable readings to determine a slope and this slope to use for comparison. On the one hand, linear approaches can do so also approaches higher Order to be taken as a basis.

According to one further advantageous embodiment of the device according to the invention are means for differentiating the course of the first and / or formed of the second electrical signal.

So can directly, for example, by a differentiator each current slope of the first electrical signal and / or the second electrical signal are evaluated.

Especially Also advantageous is a device in which the comparison unit is designed so that not only the slope, but also a Offset of the first and / or the second electrical signal consideration Find.

According to one further advantageous embodiment of the device according to the invention are evaluation means for evaluating the courses of the first and / or the second electrical signal and / or to evaluate the outputs provided the comparison unit.

• – Wahrscheinlichkeit eines vorliegenden Gegenstandes im Öffnungsbereich;
• – Zuordnung des Gegenstandes zu einem Messfühler; und
• – Eindringgeschwindigkeit des Gegenstandes in den Öffnungsbereich.

In this context, it is particularly preferred that the evaluation means are designed such that at least one of the following information is obtained:

• - probability of a present object in the opening area;
• - Assignment of the object to a sensor; and
• - Penetration speed of the object in the opening area.

Farther In this context, it is preferable that the evaluation means at least partially implement this information into the collision signal. This means in particular that the collision signal at least to extract at least part of the above information are.

According to one another preferred embodiment of the device according to the invention assign the sensors each have a sensitive area and the probes are designed so that these sensitive areas at least in overlap a subarea.

According to one Another aspect of the invention proposes a motor vehicle which comprises at least one movable adjusting element, in which the opening area the adjusting element monitored by the method according to the invention is and / or which comprises a device according to the invention.

Especially it is preferred in this context that the adjustment while the closing or opening movement makes a move, which defines a direction of movement or a plane of movement, wherein probe on both sides of the leading through a center of the adjusting element Movement direction or plane are formed.

For example can so probe be formed on both sides of a central axis of the tailgate, so that a one-sided pinching an object when closing the Boot lid can be detected in an advantageous manner. By such a recognition of a one-sided entrapment can in particular a damage the adjustment be effectively avoided, as appropriate countermeasures can be taken if the intrusion of the object is a particular sensor and so that a certain portion of the adjustment can be assigned is.

The above for the inventive method disclosed details and advantages are on the device according to the invention and the motor vehicle according to the invention and applicable. The same applies to the device according to the Invention or the motor vehicle according to the invention disclosed advantages and details related to the inventive method and the motor vehicle according to the invention or the device according to the invention are transferable and applicable.

in the Following, the invention will be described in more detail with reference to the accompanying drawings. The invention is not limited to the exemplary embodiments shown. It demonstrate:

1 schematically a first embodiment of a motor vehicle, in which an opening portion of a trunk is monitored according to the invention;

2 schematically a possible course of the signals,

3 schematically another possible course of the signals,

4 schematically a further course of the signals,

5 schematically a rear view of a motor vehicle,

6 schematically an embodiment of a device according to the invention, and

7 schematically a further embodiment of a device according to the invention.

1 schematically shows a section of a motor vehicle 1 , This motor vehicle 1 has a movable adjusting element, namely a trunk space cover 2 on. The trunk lid 2 is via an articulated arm 3 at a point of reference 4 hinged. By a motor 5 and a gearbox 6 is the point of departure 4 eccentrically movable, causing over the articulated arm 3 the trunk lid 2 can be closed. During the closing movement of the boot lid 2 this moves in the direction of the arrow 7 , The trunk lid 2 clamps together with the corresponding bodywork 8th an opening area 9 on that through the trunk lid edge 10 and the body edge 11 is limited. At the corresponding body edge 11 is a first sensor 12 and a second sensor 13 educated. The first sensor 12 gives a first electrical signal 14 and the second sensor 13 a second electrical signal 15 which depends on a property of at least a part of the opening area 9 are. In the present embodiment, the sensors are 12 . 13 to capacitive sensors, their electrical signals 14 . 15 depending on the capacitance in the sensitive area of the sensor 12 . 13 and thus in the opening area 9 are. Depending on a comparison of the course of the first electrical signal 14 with that of the second electrical signal 15 on an object 25 in the opening area 9 is closed.

Under an object 25 In particular, a person or part of a person is understood as a hand. The object 25 changes the capacity of the item 25 and the sensors 12 . 13 formed capacitors. The capacity change is determined accordingly and, for example, when a predeterminable limit value is exceeded on an object 25 in the opening area 9 closed.

2 shows schematically the progressions of the first electrical signal 14 and the second electrical signal 15 The abscissa represents the time, the ordinate a signal strength, each in relative units. From a comparison of the two signal curves 14 . 15 is a deviation of the signals clearly erken nen, whereby the penetration of an object in the sensitive area and thus in the opening area 9 was detected.

3 schematically shows the course of a difference signal 16 between a first electrical signal 14 and a second electrical signal 15 , The abscissa illustrates the time, the ordinate the difference signal from the first signal 14 and second signal 15 , each in relative units. The difference signal 16 first fluctuates around the value 0. These fluctuations around the value 0 are based on the fact that both signals 14 . 15 include a plurality of measurements that include noise. As a result of this noise, even with fundamentally similar or identical signal characteristics, there are slight differences between the two signals, which are reflected as noise in the difference signal 16 demonstrate. A peak 17 shows a big difference between the two signals 14 . 15 , This peak 17 is greater than a limit in absolute value 18 , making this an intrusion of an object 25 in the opening area 9 the adjusting element is closed. The peak 17 lies at a time t _p , in addition an object in the sensitive area of the first 12 and / or the second sensor 13 took place. The motor 5 of the device 1 can thus either be turned off at the time t _p or set in rearward movement. If, for example, a shutdown of the engine 5 , it could be activated again at the time t _f , since then the difference signal is smaller than the limit value 18 has become and thus no longer subject in the opening area 9 is present.

4 shows a course of a first electrical signal 14 in the neckline in detail. The abscissa represents the time, the ordinate a signal strength, each in relative units. The course of the first electrical signal 14 consists of a plurality of measured values 19 together. Advantageously, the comparison according to the invention does not become a measured value 19 but rather a value 20 , the measured values which can be assigned to at least two points in time 19 includes, ie at least two measured values 19 based. In this embodiment, the values become 20 by averaging two or more measured values 19 receive. Thus, influences such as noise or measurement errors can be compensated in an advantageous manner. This advantageously prevents malfunctions that can occur, for example, when the comparison of the courses of the first 14 and the second electrical signal 15 due to the noise a limit 18 exceeds, although no object in the opening area 9 has penetrated.

5 schematically shows a section of a motor vehicle according to the invention 1 , The car 1 includes one on a bodywork 8th damaged tailgate 21 , The tailgate 21 represents a movable adjusting element. In the tailgate 21 is a first pair of sensors 22 and a second pair of probes 23 educated. The sensor pairs 22 . 23 each comprise a first sensor 12 and a second sensor 13 as described above. In contrast to the above exemplary embodiment, the measuring sensors are the sensor pairs 22 . 23 in the tailgate 21 educated. These are sensors 12 . 13 , each of which emit an electrical signal, which depends on a property in the opening area of the tailgate 21 is. These are inductive and / or capacitive proximity sensors. The signals of the sensor pairs 22 . 23 are compared as set forth above according to the invention and depending on this range is on an object 25 in the opening area 9 closed. The tailgate 21 has a movement plane 24 up through the centerline of the tailgate 21 and the direction of pivotal movement of the tailgate 21 when opening and / or closing is defined. The sensor pairs 22 . 23 each have a sensor on opposite sides of the plane of motion 24 on. The second pair of probes 23 is in particular symmetrical to the plane of motion 24 educated.

6 schematically shows an embodiment of a device according to the invention comprising a first sensor 12 , which is a first electrical signal 14 which depends on a property of at least a part of the opening area 9 is, and a second probe 13 , which is a second electrical signal 15 which depends on a property of at least a part of the opening area 9 is. The probes 12 . 13 are with a comparison unit 26 connected. The comparison unit 26 is suitable, depending on a comparison of the course of the signals 14 . 15 a collision signal 27 to disclose whether an object is identifiable 25 in the opening area 9 is present.

7 schematically shows a further embodiment of a device according to the invention, in addition to the first embodiment, two differentiating means 28 the electrical signals 14 . 15 so that in the comparison unit 26 the gradients of the courses of the electrical signals 14 . 15 be compared. The collision signal 27 is in evaluation 29 headed, in which the collision signal 27 and / or the first 12 and / or second electrical signal 13 is evaluated.

Advantageously, the position of the adjusting element from the electrical signals 12 . 13 be determined. For this purpose, a comparison with a reference curve of the signals 12 . 13 required. The reference curve depicts the normal closing or opening process, each one being Time or each capacitance / induction measured value is associated with an opening angle or an opening degree of the adjusting element. This comparison can, for example, in the evaluation 29 and / or the comparison unit 26 respectively.

The inventive method and the device according to the invention advantageously allows the realization of a pinch protection in electromotive moving adjusting elements 2 of motor vehicles 1 ,

1

motor vehicle

2

trunk lid

3

articulated arm

4

reference point

5

engine

6

transmission

7

arrow

8th

body

9

opening area

10

Trunk lid edge

11

body trim

12

first probe

13

second probe

14

first electrical signal

15

second electrical signal

16

difference signal

17

peak

18

limit

19

reading

20

value

21

tailgate

22

first Probe pair

23

second Probe pair

24

movement plane

25

object

26

comparing unit

27

collision signal

28

medium to differentiate

29

evaluating means

t _p

time of the peak

t _f

time falling below the limit

Claims (19)

Method for recognizing an object ( 25 ) in the opening area ( 9 ) of a movable adjusting element ( 2 . 21 ), in which at least a first ( 14 ) and a second electrical signal ( 15 ), both signals ( 14 . 15 ) depending on a property of at least part of the opening area ( 9 ), characterized in that in dependence on a comparison of the course of the first electrical signal ( 14 ) with that of the second electrical signal ( 14 ) on an object ( 15 ) in the opening area ( 9 ) is closed. The method of claim 1, wherein the property at least one of the following electrical quantities comprises: - an electrical capacity and - one electrical inductance. Method according to Claim 1 or 2, in which a collision signal ( 27 ) is generated, on the basis of which it is recognizable whether an object ( 25 ) in the opening area ( 9 ) is present. Method according to one of the preceding claims, in which the first ( 14 ) and the second electrical signal ( 15 ) of one sensor each ( 12 . 13 ) to be generated. Method according to one of the preceding claims, in which the course of the electrical signals ( 14 . 15 ) each have a plurality of measured values ( 19 ), wherein the comparison of the course of the electrical signals ( 14 . 15 ) the comparison of a first value ( 20 ) of the first electrical signal ( 14 ) and a second value ( 20 ) of the second electrical signal ( 15 ), the values ( 20 ) are each assignable to a time. Method according to one of Claims 1 to 4, in which the course of the electrical signals ( 14 . 15 ) each have a plurality of measured values ( 19 ), wherein the comparison of the course of the electrical signals ( 14 . 15 ) the comparison of a first value ( 20 ) of the first electrical signal ( 14 ) and a second value ( 20 ) of the second electrical signal ( 15 ), the values ( 20 ) are each assignable at least two times. Method according to one of the preceding claims, wherein for comparison the slope of the course of the first ( 14 ) and the second electrical signal ( 15 ) is taken into account. Method according to one of Claims 3 to 7, in which the collision signal ( 27 ), when the absolute value of the difference of the compared signals ( 14 . 15 ) a predefinable limit ( 18 ) exceeds an item ( 25 ) in the opening area ( 9 ) signals. Method according to one of Claims 3 to 8, in which the collision signal ( 27 ) comprises a binary signal. Method according to one of Claims 3 to 9, in which the collision signal ( 27 ) comprises at least one of the following information: - probability of a given subject ( 25 ) in the opening area ( 9 ); - assignment of the object ( 25 ) to a sensor ( 12 . 13 ); - penetration rate of the object ( 25 ) in the opening area ( 9 ). Method according to one of the preceding claims, in which the first electrical signal ( 14 ) a property in a first sensitive area and the second electrical signal ( 15 ) detects a property in a second sensitive area and the sensitive areas overlap one another at least in a partial area. Device for detecting an object ( 25 ) in the opening area ( 9 ) of a movable adjusting element ( 2 . 21 ) comprising at least one first sensor ( 12 ) and a second sensor ( 13 ), the first sensor ( 12 ) a first electrical signal ( 14 ) and the second sensor ( 13 ) a second electrical signal ( 15 ) which depends on a property of at least part of the opening area ( 9 ), characterized in that a comparison unit ( 26 ) which is dependent on a comparison of the course of the first electrical signal ( 14 ) with that of the second electrical signal ( 15 ) a collision signal ( 27 ), by means of which it can be recognized whether an item is in the opening area ( 9 ) is present. Apparatus according to claim 12, wherein the sensors ( 12 . 13 . 22 . 23 ) Comprise sensors which detect at least one of the following operations: - touching the sensor by an object ( 25 ) and - approximation of an object ( 25 ) to the sensor. Device according to one of claims 12 or 13, in which the sensors ( 12 . 13 . 22 . 23 ) comprise at least one of the following sensors: a capacitive sensor and an inductive sensor. Device according to one of Claims 12 to 14, in which means ( 28 ) for differentiating the course of the first ( 14 ) and / or the second electrical signal ( 15 ) are formed. Device according to one of Claims 12 to 15, in which evaluation means ( 29 ) for evaluating the courses of the first ( 14 ) and / or the second electrical signal ( 15 ) and / or for the evaluation of the outputs of the comparison unit ( 26 ) are formed. Device according to one of claims 12 to 16, in which the measuring sensors ( 12 . 13 . 22 . 23 ) each have a sensitive area and the probes ( 12 . 13 . 22 . 23 ) are formed so that these sensitive areas overlap at least in a partial area. Motor vehicle ( 1 ) with at least one movable adjusting element ( 2 . 21 ), in which the opening area ( 9 ) of the adjusting element ( 2 . 21 ) is monitored by the method according to one of claims 1 to 11 and / or comprising a device according to one of claims 12 to 17. Motor vehicle ( 1 ) according to claim 18, wherein the adjusting element ( 2 . 21 ) during the closing or opening movement performs a movement, the one movement direction or a movement plane ( 24 ), where probes ( 12 . 13 . 22 . 23 ) on both sides by a center of the adjusting element ( 2 . 21 ) leading movement direction or - level are formed.