DE102009000740A1 - Passenger head position e.g. vertical position, determining method for vehicle seat of passenger car, involves determining lateral and/or vertical position of head of vehicle passenger with respect to head-rest of vehicle seat - Google Patents

Abstract

The method involves impinging of two electrodes with a measuring signal, where the electrodes are formed from partial electrodes (210a-210d). Capacitance (C) between the electrodes is detected with respect to the impinged measuring signal, where the capacitance represents a lateral and/or vertical position of a head of a vehicle passenger with respect to a head-rest of a vehicle seat. The lateral and/or vertical position of the head of the vehicle passenger is determined with respect to the head-rest of the vehicle seat based on the capacitance. Independent claims are also included for the following: (1) a control device for performing a method for determining a position of a head of a passenger on a vehicle seat (2) a computer program product with a program code stored on a machine-readable medium for performing a method for determining a position of a head of a passenger on a vehicle seat (3) a sensor arrangement for detecting a lateral position of a head of a vehicle passenger with respect to a head-rest of a vehicle seat.

Description

State of the art

The The present invention relates to a method according to claim 1, a control device according to claim 10, a computer program product according to claim 11, a sensor arrangement according to claim 12 and a Headrest according to claim 15.

In The last few years are the cost of the so-called Cervical spine distorsions (whiplash), also Whiplash injuries called, as a result of a rear impact in the high-powered countries for the insurance industry increased significantly and now belong to the group of the most expensive injuries. At the Rear impact, the most common with 54% collision type Accidents between cars threaten serious injury the cervical spine. Take this type of injury It accounts for around 80% of total injuries and causes Insurance also accounts for around 75% of all injury costs. This accident type is also very common in Japan and accounts for around 31% of all Accidents involving cars are a high priority in Asia Area. Thus, the type of injury attains, even if by doing so No serious or even fatal injuries be a high priority since the economic Damage by the follow-up costs is very large.

Driven by this motivation was a so-called PCS-WIL system 100 as shown 1a developed, which was first introduced in vehicle models of an upscale brand. "PCS" is an abbreviation for "Predictive Crash Safety System" and "WIL" an abbreviation for "Whiplash Injury Lessening". A system based on a 77 GHz short-range radar sensor 110 , which is installed in the rear bumper, controls via a collision detection computer 120 and a body control computer 130 a warning (for example, via a control of the brake lights 140 ) and an activation unit 150 an electromotive headrest. For this purpose, the signal is processed by means of a control unit and in the event of a collision, the headrest is moved to the head of the occupant. The core of the headrest is next to the electric motor a capacitive sensor 160 according to the 1b , which detects the distance in the direction of travel between occupant and headrest. If a certain distance and thus a certain capacity is reached, an electric motor is switched off, based on the sensor signal. The structure of the system and the sensors are in the 1a ) respectively. 1b ). The sensor principle described thus serves to determine the distance in the vehicle longitudinal direction between the head of the occupant and the headrest. The procedure is in the JP2006218083A or the DE 10 2007 039 439 A1 under the title "Apparatus and Method for Controlling a Headrest".

One major problem besides the actual classification of the Inmates is also its position relative to an airbag and others z. B. contained in the seat retaining means. For this purpose were already as mentioned above, some procedures are described below Provide another capacitive sensor. Other methods which over optical systems work, so z. B. interior cameras can calculate the position of the occupant from the video image. Indirect procedures By means of weight-based systems are also patent applications described by the present applicant.

to further improvement of occupant safety will be at a reversible and an irreversible actuator within a security seat worked. One of the core functions of this seat is pneumatic and / or electromotive activatable side pads in the seat back and in the seat. Depending on the Driving conditions are these systems to protect the occupant especially in case of side collisions already in the pre-crash area (ie in the area shortly before a fall).

aim The effort is to reduce the severity of the injury Inmates by reducing occupant movement towards intruding Structures. However, this only works as long as the inmate sitting in a opti paint position. Is the occupant z. B. by a Slingshots can deflect the corresponding Protection system such as pre-crash-activated systems or irreversible Retaining means (head airbag) can no longer grip and even counterproductive in the worst case. something similar Situations also arise when the occupant is permanently distracted is, for. B. sleeping position in the passenger. In these borderline cases a decision is necessary, whether the reversible or irreversible Retention means are triggered or not.

Disclosure of the invention

In front This is the background of the present invention. furthermore a control unit which uses this method, finally a corresponding computer program product and a sensor arrangement according to the independent Claims presented. Advantageous embodiments emerge from the respective subclaims and the following description.

• – Beaufschlagen von zumindest zwei Elektroden mit einem Messsignal;
• – Erfassen einer Kapazität zwischen den Elektroden ansprechend auf das beaufschlagte Messsignal, wobei die Kapazität zumindest eine in Fahrtrichtung gesehen laterale und/oder eine vertikale Position des Kopfes eines Fahrzeuginsassen in Bezug zu einer Kopfstütze eines Fahrzeugsitzes repräsentiert; und
• – Ermitteln der lateralen und/oder vertikalen Position des Kopfes des Fahrzeuginsassen in Bezug zur Kopfstütze des Fahrzeugsitzes auf der Basis der erfassten Kapazität.

The present invention provides a method for determining a position of a head of an occupant on a vehicle seat, the Ver drive the following steps:

• - Applying at least two electrodes with a measurement signal;
• Detecting a capacitance between the electrodes in response to the applied measurement signal, the capacitance representing at least one lateral and / or vertical position of the head of a vehicle occupant with respect to a headrest of a vehicle seat, viewed in the direction of travel; and
• - Determining the lateral and / or vertical position of the head of the vehicle occupant with respect to the headrest of the vehicle seat on the basis of the detected capacity.

The The present invention further provides a controller that for carrying out and / or controlling (the) steps of the above method is formed. Also through this Embodiment of the invention in the form of a control device can the object underlying the invention quickly and efficiently be solved.

Under a control device can in the present case an electrical device be understood, the sensor signals processed and in dependence of which outputs control signals. The control unit can have a Have interface that formed hardware and / or software can be. For a hardware training For example, the interfaces can be part of a so-called System ASICs, the various functions of the controller includes. However, it is also possible that the interfaces own integrated circuits are or at least partially off consist of discrete components. In a software-based Training, the interfaces may be software modules, for example, on a microcontroller in addition to other software modules available.

From Advantage is also a computer program product with program code, the on a machine-readable medium such as a semiconductor memory, stored in a hard disk memory or an optical memory is and to carry out and / or control the steps the method according to one of the embodiments described above if the program is on a controller and / or a data processing system is running.

Farther The present invention provides a sensor arrangement for detection at least one lateral position of a head of a vehicle occupant with respect to a headrest of a vehicle seat, wherein the sensor arrangement comprises a plurality of sub-electrodes, the are arranged in rows and in a plurality of columns.

The The present invention is based on the recognition that simple Way to improve occupant safety can be used when capacitive sensors are used, the one lateral and / or vertical position of a head of a on a Vehicle seat sitting occupants recognize. This capacitive detection The position of the head can be done without major Effort and at the same time perform very reliable. In particular, for such recognition of the head a sensor array can be used, in the sub-electrodes line-shaped are arranged in a plurality of columns, so that through the Evaluation of the response signals of different sub-electrodes, the were subjected to one (or more) measurement signals, one reliable determination of a lateral deflection of the Occupant head in relation to a direction of travel of the vehicle possible is. For detecting a vertical position of the occupant's head can be used according to a sensor arrangement in which the sub-electrodes arranged in different vertical position are.

The present invention offers the advantage that, for example, by a simple and inexpensive placement of a corresponding Sensor arrangement in a headrest of a vehicle seat the Detecting the position of the occupant head reliably and technically easy to realize. In particular, the Evaluation of the obtained capacitance signals in use AC or AC measurement signals very simple performed by the evaluation of a resulting resonant frequency be when the sub-electrodes as the capacity of a resonant circuit be used. Further, the obtained resonance frequencies of two (carried out independently) Measurements (preferably on different sub-electrodes) with each other compared, the actual can be very reliable Direction and deflection of the position of the occupant head in comparison be recognized for headrest. This is only one Loading of different electrodes (or partial electrodes) required with the same or different measurement signals; the Selection of the respective electrodes to be acted upon as well as the evaluation the received signals can be through a central computer or control unit respectively. Furthermore, in a further evaluation, the obtained (preferably at different partial electrodes) detected Capacities are also set in relation to each other (quotient formation), so that the resulting relationship is a statement about the deflection of the position of the occupant head compared to Headrest allowed.

It is favorable if, prior to the step of loading, a step of the electrically conductive connection of at least two partial electrodes to ei ner electrode is formed, wherein the electrode formed from the partial electrodes is acted upon in the step of applying the measurement signal. As a result, a more precise evaluation of the signals obtained is possible because the sensor area is larger due to the interconnected partial electrodes and thus the sensitivity is higher. By the possibility of selecting the interconnection of different partial electrodes, a very flexible possibility for measuring the individual deflection parameters is also provided.

In another embodiment of the present invention may be the step of electrically conductive bonding on a stored in a memory information about an arrangement position of the sub-electrodes are based. It can in the step of electrically connecting sub-electrodes with each other are connected, the information in memory on an arrangement substantially the same horizontal axis or an arrangement on substantially the same vertical axis or their information in memory an arrangement on different lateral and vertical Represents axes. Such an embodiment The present invention offers the advantage that a concrete Interconnection of the individual sub-electrodes already defined in advance can be, for these specific interconnections the correspondingly expected measurement results or the distances to be determined therefrom deposited between the head and sensor array in a memory can. The measurement of the position of the head can then be the very easy in the form of multiplexing the various predefined ones Interconnections (which provide information about the corresponding Arrangement position, each to be interconnected sub-electrodes contained in the sensor arrangement), wherein the evaluation possible using the result values stored in the memory is. Such an evaluation can be very fast and technically easy to perform and is therefore for Time-critical applications an advantage.

Also the method may further comprise steps of applying another measurement signal at two electrodes and detecting another capacitance between these electrodes in response to the applied further measurement signal comprise, wherein in the step of applying the further measurement signal at least one electrode is applied, extending from the electrode differs in the step of applying the measurement signal is applied and wherein the additional capacity at least a seen in the direction of travel lateral and / or vertical position the head of a vehicle occupant with respect to a headrest represents a vehicle seat and wherein the step determining the lateral and / or vertical position of the head the vehicle occupant further based on the detected further Capacity takes place. Such an embodiment The present invention offers the advantage that a further Capacity can be detected with a measurement configuration resulting from a measurement configuration of the (first measured) capacity different. This procedure requires at least three electrodes in a sensor arrangement that is characterized by different measuring signals be charged. From the capacity and the other Capacity can then be much more precise on the actual position of the occupant's head to be closed when this is possible only by evaluating a capacity is.

Also may in a further embodiment of the present Invention in the step of determining the lateral and / or vertical Position of the occupant's head using a comparison between capacity and further capacity be determined. Such an embodiment of the present invention Invention has the advantage that technically very simple and thus very cost-effective a precise detection of lateral and / or vertical position of the occupant's head possible is.

Farther is it possible, in the step of applying an AC voltage or to use an AC measurement signal. Alternatively or in addition can also be the step of determining on the basis of an evaluation at least one resonance frequency. Such embodiments The present invention offers the advantage that through the use of of different frequencies that frequency can be determined in which a resonant circuit with the (measured) capacity resonates. From a location and a sign the measured resonant frequency with respect to a resonant frequency, for a head in a rest position in front of the headrest is measured, then the actual current lateral and / or vertical position of the occupant's head, even in small resulting capacities simple and accurate be determined.

A very precise and accurate signing can then take place if in the step of determining a deflection of the head the vehicle occupant from a lateral and / or vertical rest position in relation to the headrest based on recognition of a Amount of deviation of a detected resonance frequency from one Resting position resonant frequency, that of a resonant frequency corresponds, in which the vehicle occupant is in a rest position located on the vehicle seat. In this case, a detection of a Direction of the deflection from a sign of the deviation of the detected Resonant frequency from the rest position resonance frequency.

The method may further include a step of blocking a triggering of a security by detecting in the step of determining a lateral and / or vertical position of the head of the vehicle occupant, which exceeds a predetermined maximum deflection from a rest position. The blocking step can advantageously ensure that a person restraint device is no longer triggered after or during a fallover when an occupant on the vehicle seat is no longer in a predefined position. In this way, it is possible to avoid injuries that would occur as a result of such triggering of a person restraint device if the vehicle occupant is no longer in the optimum position on the vehicle seat when the restraint device is triggered.

In In another embodiment of the invention, the step of blocking are executed when in the step of Determine a lateral and / or vertical position of the head the vehicle occupant is detected, the predetermined maximum Deflection from the rest position longer than a predetermined Time span exceeds. Such an embodiment The invention offers the advantage that a plausibility of the detected deflection is possible, so that short-term measurement error not to a shutdown of the personal restraint to lead.

In another embodiment of the present invention Further, the partial electrodes may be formed in a plurality of Lines be arranged. This offers the advantage that through a Matrix-shaped arrangement of the sub-electrodes a very precise Detecting the occupant's head in both lateral and vertical Direction is possible. The measurements can be the position of the occupant's head in the lateral and vertical directions one after the other and / or by different measuring signals also at the same time done different sub-electrodes.

A simple and at the same time very flexible evaluation sensor arrangement can be created by the fact that the sub-electrodes individually from outside the sensor assembly contacted or closed at least a partial electrode field are interconnected.

Around the position of an occupant's head relative to the headrest Optionally, the present invention can also be used as a headrest be implemented for a vehicle seat of a vehicle itself, the headrest having a sensor arrangement according to the has the above statements.

The The invention will be described below with reference to the accompanying drawings exemplified in more detail. Show it:

1a -B illustrations of a sensor arrangement and its function, as known in the art;

2a -B representations of different wiring options of sub-electrodes for detecting a distance of the occupant head of the headrest in the x direction

3 a diagram illustrating a determination of a distance of the occupant head of the headrest in the x direction from a detected capacity;

4a -B representations of different wiring options of sub-electrodes for detecting a distance of the occupant head of the headrest in the y-direction

5 a diagram illustrating a determination of a distance of the occupant head of the headrest in the y direction from a detected capacity;

6a -B representations of different Verschaltungsmöglichkeiten of sub-electrodes for detecting a distance of the occupant head of the headrest in the z-direction

7 a diagram illustrating a determination of a distance of the occupant head of the headrest in the z direction from a detected capacity;

8th a representation of a further arrangement and Verschaltungsmöglichkeit of electrodes for detecting the capacity or of a plurality of capacitors;

9 a schematic representation of the measuring principle of an embodiment of the present invention;

10 a schematic representation of another measuring principle in a variant in which the capacitive sensor is installed in a peripheral sensor (eg peripheral acceleration sensor);

11 a block diagram of the exemplary procedure in the evaluation of the detect signals or capacitances; and

12 a flowchart of an embodiment of the present invention as a method.

The same or similar elements may be provided in the following figures by the same or similar reference numerals, wherein a repeated description is omitted. Furthermore, the figures of the drawings whose Be As well as the claims numerous features in combination. It is clear to a person skilled in the art that these features are also considered individually or that they can be combined to form further combinations not explicitly described here. Furthermore, the invention in the following description may be explained using different dimensions and dimensions, wherein a mention of these dimensions and dimensions is not to be understood as meaning that the invention is limited to these dimensions and dimensions.

Around a control of a person restraint means in a timely manner activate or deactivate when a Person on the vehicle seat outside the predetermined optimal range of action of the restraint is located Capacitive sensors are to be used in the seat, just these irreversible and / or reversible retention means in the Control seat and / or on the side structure (head and side airbags) or release. The purpose of the approach presented here is to alternatively frontal occupant position based on the relocation of the Head relative to the seat axis by means of a (preferably in the Headrest installed) to sense capacitive sensors. Another goal of the approach presented here is to create a processing rule to provide a drive or suppression the reversible and irreversible restraint installed in the seat allowed (eg, electric motor and / or pneumatically activated Side cushions in a vehicle seat). Another goal of the presented here The approach is to provide a processing rule that a control or suppression in the vehicle structure built reversible and irreversible retention means allowed (eg electromotive activatable door panel or side and curtain airbags).

One important aspect of the present invention is thus the determination the lateral occupant position using a capacitive sensor (preferably in the headrest). Furthermore it is an important aspect to provide a processing instruction to the present invention, so that a control of a security system preferably in Seat and the head airbag done.

One significant advantage of the invention in a favorable embodiment is a suppression of the control of a Sitzaktorik and the head airbag at laterally displaced occupants (lateral OOP), such as B. in skid maneuvers or by comfort / user-driven Occupant behavior. Another important advantage of the invention is that the existing sensor technology is modified and functional can be extended. This can lead to development costs be reduced. The sensor could thus also as additional Sensor serve to the distance in x-direction (ie in the direction of travel of the vehicle) and thus can be further functions build on this (Frontal OOP, comfort adjustment of the headrest).

One Another advantage of the approach proposed here is the direct sensory detection of head displacement. For other procedures can be through the coupling over the body Estimation errors occur. Also is the sensory evaluation less costly than a capture over a Video system. Thus, the approach proposed here offers the advantage also the position of the head in relation to the headrest axis in z direction and a first possible estimate to deliver the body size of the occupant. Another advantage is the expansion option and Linkage with other systems such as driving dynamics. has the vehicle the possibility of the driver or passenger By weight or weight class, this information may be if necessary continue to be used and accordingly in the evaluation logic to be taken into account.

A Another advantageous feature is the coupling with future Environment sensor which is installed in the side area. In combination this can be better votes between triggering decision and potential collision opponents.

By the targeted consideration of the occupant head position This sensor represents a step towards individualized safety represents.

The The invention described below can be in a Airbag control unit or another control unit z. B. in a favorable variant in the seat control unit realize. The exchange of data happens for example via a bus system or the direct coupling to the control unit with corresponding sensor evaluation. Others, e.g. B. wireless communication capabilities, are also possible.

A

= wirksame Fläche in der die Kapazität aufgenommen werden kann;

I

= Abstand der Platten (im vorliegenden Fall);

ε

= Dielektrizitätskonstante

In a first embodiment, the invention provides that the sensor is installed on the basis of a capacitive measuring principle in the headrest. The capacitive measuring principle is based on the capacitance of a capacitor: C = ε · A / I in which

A

= effective area in which the capacity can be absorbed;

I

= Distance of the plates (in the present case);

ε

= Dielectric constant

R

= Radius der Kugel ist (≈ Radius eines Kopfes).

This formula is usually valid if the spatial extent of the capacitor plates is much larger than their distance, ie if the electric field can be considered homogeneous. The capacity assumed for this case can be calculated on the basis of a free sphere and leads to the relationship: C = 4 · π · ε · R in which

R

= Radius of the sphere is (≈ radius of a head).

dabei ist

ω

= Eigenfrequenz und

X

_c = kapazitiver Widerstand.

The capacitance is influenced essentially by the dielectric constant. The human head, including the neck, is a significant factor in influencing that constant, changing its capacity. This change is mostly detected by the change in capacitance, which is calculated as follows:

is there

ω

= Natural frequency and

X

_c = capacitive resistance.

Of the Capacitive resistance can be detected in a resonant circuit and ultimately leads to detuning of the resonant circuit. This can be seen as a measure of a deviation become. The sensor should conveniently capture in the lateral direction, as shown in the following description can be seen in more detail.

For example, the sensor for detecting the position of the occupant's head, a structure as shown 2a to have. There is a sensor field 200 provided in which a plurality of part sensors 210a Are arranged in a row-shaped and column-shaped. In the presentation off 2a are four part sensors 210a -D, which are for example electrode surfaces, arranged square in two rows and two columns. These part sensors 210a D can be used to measure a position of the occupant's head in the x-direction (ie in the direction of travel of a vehicle), in the y-direction (ie transversely or laterally to the direction of travel of the vehicle) or in the z-direction (ie to determine the size of the occupant) be interconnected differently. For example, for determining a distance of the occupant head from the sensor arrangement 200 in the x direction, the partial electrode 210a top left with the partial electrode 210d at the bottom right to a first electrode. In addition, the partial electrode 210b top right with the partial electrode 210c at the bottom left to a second electrode. A capacitance C can then be detected between the first and the second electrode, and from this the distance of the occupant's head in the x-direction from the sensor arrangement 200 , which is installed, for example, in a headrest, are determined. The capacitance C can be done either by determining a resonant frequency having a resonant circuit in which the capacitance C is included, or other methods for determining capacitances can be used. In determining the distance of the occupant's head in the x-direction, a predetermined relationship between the detected capacity and the distance of the occupant's head from the sensor arrangement (for example, by a in diagram, as shown in FIG 3 is shown). In the presentation off 3 is on the abscissa a distance of the occupant head of the sensor assembly 200 in cm, the ordinate representing the detected capacitance C in pF. The interconnection according to 2a for example, could provide values that are in 3 represented by the line marked with a rhombus. In order to check or to validate the result of the distance of the occupant's head in the x-direction, a second interconnection of the partial electrodes 210a -D be done as they are in 2 B is shown. Here are the other two upper sub-electrodes 210a and 210b to a first electrode under the two lower sub-electrodes 210c and 210d connected to a second electrode, wherein between the first and the second electrode, the capacitance is detected. Here, the values could be obtained as indicated by the line marked me rectangles in 3 is shown.

In this way, a recognition of the head position by different connection of different capacitance detection elements 210 possible. As a result, for example, the headrest can be brought into the optimum position both before and in the event of a crash, or a deactivation can take place in the event of a crash, or further occupant protection devices can be activated or deactivated.

In order to determine the position of the occupant's head in the lateral direction, that is to say in the direction of the y-axis, a further interconnection of the subelectrodes can take place 210a -D according to the 4a be made. In a third interconnection, the two upper sub-electrodes 210a and 210b are interconnected to a first electrode and the partial electrode 210c bottom left to be used as a second electrode for detecting the capacity. In such an interconnection according to 4a For example, values may be obtained that are indicated as a diamond-marked line in a graph according to FIG 5 are representable. The diagram according to 5 is according to the diagram 3 built up. For checking or plausibility checking, a further interconnection of the sub-electrodes 210a -D the sensor arrangement 200 done as they are in 4b is shown. Here are the two upper part electrodes 210a and 210b interconnected to egg ner first electrode and the partial electrode 210d bottom right used as a second electrode for measuring capacitance. A relationship between a distance of the occupant's head in the y-direction and the capacity obtained in 5 represented by the line marked with rectangles.

In this way, a recognition of the lateral head position by different connection of different capacitance detection elements 210 possible. As a result, for example, retaining means for a lateral protective effect (eg thorax and / or head airbag and actuator in the seat) can be activated or deactivated.

For measuring the distance of the occupant head in the z direction, an interconnection of the sub-electrodes 210 the sensor arrangement 200 according to the 6a respectively. Here are the two left partial electrodes 210a and 210c to a first electrode and the partial electrode 210d bottom right used as second electrode for capacitance measurement. The obtained capacity with respect to a height of the occupant's head in the z-direction can be in 7 represented by the line marked with diamonds. The presentation of the 7 corresponds to the representations of the 5 and 3 , For checking or plausibility checking, a further interconnection for detecting the position of the occupant's head in the z-direction according to 6b respectively. In this case, the two left part electrode 210a and 210c interconnected to a first electrode and the partial electrode 210b used on the upper right as second electrode for capacitance measurement. This will result in a capacity curve with respect to a height position of the occupant's head, the in 7 is represented by a line marked with rectangles.

In this way, vertical head position detection is achieved by different connection of different capacitance sensing elements 210 possible. As a result, for example, the restraining device has the information as to what size the object / occupant has on the seat. This information can be incorporated into the retention strategy for activating all restraint means.

Consequently will be seen that by several measurements of the capacity at differently interconnected capacitive structures or partial electrodes the Position of the head in the X, Y and Z direction can be determined. The different configurations can successively switched through (for example in the multiplex method), whereby again only one evaluation circuit is necessary.

In another embodiment of the present invention, the headrest may be provided with two capacitances (arranged horizontally on a headrest), which may possibly be connected in series, so that a total capacity can be calculated. Such an arrangement is in 8th shown. By the two capacitances C1 and C2, which are each formed by the tapping of two separate laterally arranged electrode surfaces, two capacitance values can be obtained, which can be used at the same time for plausibility and thus enable fast and reliable information about the position of the occupant's head. In general, the goal in this embodiment is to obtain detuning of a resonant circuit or other type of detection when an occupant moves transversely with his head relative to the vehicle seat axis. Such an arrangement or evaluation option is in 9 shown schematically. Other evaluation options for determining a suitable evaluable characteristic, eg. B. Ratio of the capacities and according to evaluation are also conceivable.

The 9 shows the effects of the displacement of the occupant's head on the capacitances C1 and C2. In the right illustrations 9 are the resonance frequencies 910 represented by resonant circuits, each containing one of the two capacitances C1 and C2. If, for example, the occupant's head is moving from a rest position 900 in the direction of the window or door 920 a change takes place in the capacitances C1 and C2. This leads to a shift of the resonance frequencies 930 of resonant circuits, each containing the capacitance C1 or C2. This is during a movement of the occupant's head from the rest position 900 in the direction of the door or window 920 the resonant circuit has a lower resonant frequency 930 having the capacitance C1, since this first capacitance C1 becomes larger due to an approach of the occupant's head. At the same time, the resonance frequency 930 larger that resonant circuit containing the second capacitance C2, since the moving away of the occupant head, the second capacitor C2 is smaller. If, however, the occupant head of the door or the window 920 moved away, the displacement of the resonant frequency occurs 930 the respective oscillating circuits in the opposite direction, so that the resonant circuit having the second capacitance C2, the smaller resonant frequency and the resonant circuit having the first capacitance C1, the larger resonant frequency. From the magnitude of the deviation .DELTA.f between the resonant frequency occurred 930 and the resonant frequency 910 in rest position of the occupant head, the strength of the deflection or the exact position of the occupant's head determines who the.

These Dependence of the resonance frequency change of the deflection of the occupant's head is controlled by a control unit recorded and evaluated accordingly in an algorithm. The evaluation In addition to the sensor data acquisition and processing, the evaluation provide the signals.

Another possible variant of sensor unit could be designed such that a capacitance sensor in a peripheral sensor, for. B. acceleration sensor is installed, which sits in the vehicle in the B-pillar. This sensor detects a nearby head, which in turn would result in a change in capacity. A realization of the triggering algorithm would therefore be structured somewhat differently. Despite this, this variant represents a simple and cost-effective implementation and could serve as an alternative to the sensor integration described above. This possibility is again in 10 shown schematically.

One possible form of signal processing of the detected capacitance or resonance frequency is in 11 shown schematically and can be supplemented accordingly.

The evaluation in a control unit 1050 could be done so that after a sensor data acquisition 1100 the frequency shift first filtered (for example with a FIR filter) 1110 and against a threshold 1120 (which is designed as EEPROM parameter 1) is compared. In this case, the frequency shift is a measure of the deviation to the seat center axis. If the threshold 1120 exceeded (situation 1130 ), a counter is incremented (ie, for example, a calculation Z = Z + 1 is performed) or decreased accordingly (situation 1140 for example, a calculation Z = Z - 1 performed). This counter Z is in a further step compared to a second (for example EEPROM parameter 2) parameters 1150 to check whether the deflection has lasted longer than a predetermined period of time, in order to obtain an additional verification of the signal evaluation. At the same time, the sign from the filtered deviation ( 1110 ) and to that effect in one step 1160 compared whether the signs VZ are positive at time t and t - 1 (positive was defined herein as movement of the occupant towards the side window). If these conditions meet the logical AND, appropriate measures can be taken 1170 for a reversible actuator inside and / or outside of the seat, such. B. Gurtautomat, seat side bolsters, seat cushion adjustment, door inner lining, side window drive up, visual warning, etc. are controlled. Other measures include the reparameterization of pyrotechnic actuators.

A further expression provides this information as additional information available and can be used in other algorithms such as Page triggering algorithm and / or other triggering algorithms (front, Tail or rollover) as input size so that a better triggering decision of the retention means can be determined. In another possible form is the consideration of driving dynamics possible. In this case, for example, the lateral acceleration be considered and the signal of head movement opposite be evaluated these driving dynamics variables. A possible consideration could be z. B. be represented by the fact that at increased lateral acceleration a correlation between the occupant's head movement towards the side window exists or whether a situation is given by a person statically leaning against a window to sleep, for example. This information may also be shared with other systems Be made available, such as a comfort system. It is also conceivable to introduce different thresholds so that the system is different in different situations can be controlled. For example, a low threshold in reversible systems and higher threshold for irreversible Systems are selected. Likewise, with a lateral Movement of the vehicle the occupant head movement are tracked so the triggering decision in case of accident (Rollover or side collision) optimized in relation to the head position can be.

Furthermore, the present invention provides a method 1200 for determining a position of a head of an occupant on a vehicle seat, as shown in the flowchart of 12 is shown. In this case, the method comprises a step of applying 1210 of at least two electrodes with a measurement signal. Furthermore, the method comprises 1200 a step of grasping 1220 a capacitance between the electrodes in response to the applied measurement signal, the capacitance representing at least one lateral and / or vertical position of the head of a vehicle occupant relative to a headrest of a vehicle seat viewed in the direction of travel. Finally, the process includes 1200 a step of determining 1230 the lateral and / or vertical position of the head of the vehicle occupant with respect to the headrest of the vehicle seat on the basis of the detected capacity.

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

• - JP 2006218083 A [0003]
• DE 102007039439 A1 [0003]

Claims (15)

Procedure ( 1200 ) for determining a position of a head of an occupant on a vehicle seat, the method ( 1200 ) comprises the following steps: - loading ( 1210 ) of at least two electrodes with a measurement signal; - To capture ( 1220 ) a capacitance (C; C1, C2) between the electrodes in response to the applied measurement signal, the capacitance (C, C1, C2) having at least one lateral (y-direction) and / or one vertical (z-direction) viewed in the direction of travel Position of the head of a vehicle occupant with respect to a headrest of a vehicle seat represented; and - determining ( 1230 ) of the lateral and / or vertical position of the head of the vehicle occupant with respect to the headrest of the vehicle seat on the basis of the detected capacity (C; C1, C2). Procedure ( 1200 ) according to claim 1, characterized in that before the step of applying ( 1210 ) a step of the electrically conductive connection of at least two partial electrodes ( 210a -D) to an electrode, wherein the partial electrodes ( 210a -D) formed electrode in the step of applying ( 1210 ) is applied to the measurement signal. Procedure ( 1200 ) according to claim 2, characterized in that the step of electrically conductive bonding is based on information stored in a memory about an arrangement position of the sub-electrodes. Procedure ( 1200 ) according to one of claims 1 to 3, characterized in that the method ( 1200 ) further comprises the steps of applying a further measurement signal to two electrodes and detecting a further capacitance (C; C1, C2) between these electrodes in response to the applied further measurement signal, wherein in the step of applying the further measurement signal is applied to at least one electrode which differs from the electrode used in the step of applying ( 1210 ) and wherein the further capacitance represents at least one lateral (y-direction) and / or vertical (z-direction) position of the head of a vehicle occupant with respect to a headrest of a vehicle seat, and wherein the step of Determine ( 1230 ) of the lateral (y-direction) and / or vertical (z-direction) position of the head of the vehicle occupant further takes place on the basis of the detected further capacity. Procedure ( 1200 ) according to claim 4, characterized in that in the step of determining ( 1230 ) the lateral and / or vertical position of the head of the occupant is determined using a comparison between the capacitance (C1) and the further capacitance (C2). Procedure ( 1200 ) according to one of claims 1 to 5, characterized in that the step of determining ( 1230 ) on the basis of an evaluation of at least one resonance frequency ( 910 . 930 ) he follows. Procedure ( 1200 ) according to claim 6, characterized in that in the step of determining ( 1230 ) a deflection of the head of the vehicle occupant from a lateral (y-direction) and / or vertical (z-direction) rest position with respect to the headrest on the basis of detection of an amount of deviation (Δf) of a detected resonance frequency ( 930 ) from a rest position resonance frequency ( 910 ), which corresponds to a resonant frequency ( 930 ), in which the vehicle occupant is in a rest position on the vehicle seat, wherein a detection of a direction of the deviation (.DELTA.f) from a sign of the deviation (.DELTA.f) of the detected resonant frequency ( 930 ) from the rest position resonance frequency ( 910 ) he follows. Procedure ( 1200 ) according to one of claims 1 to 7, characterized in that the method ( 1200 ) further comprises a step of blocking a triggering of a safety means if, in the step of determining, a lateral (y-direction) and / or vertical (z-direction) position of the head of the vehicle occupant is detected which has a predetermined maximum deflection (Δf) from a rest position. Procedure ( 1200 ) according to claim 8, characterized in that the step of blocking is carried out if in the step of determining ( 1230 ) a lateral (y-direction) and / or vertical (z-direction) position of the head of the vehicle occupant is detected, which exceeds a predetermined maximum deflection (.DELTA.f) from the rest position for longer than a predetermined period of time. Control unit ( 1050 ) for carrying out and / or controlling the steps of a method ( 1200 ) is formed according to one of claims 1 to 9. Computer program product with program code, which is stored on a machine-readable carrier, for carrying out and / or controlling the steps of the method ( 1200 ) according to one of claims 1 to 9, when the program is stored on a control unit ( 1050 ) or a data processing system. Sensor arrangement ( 200 ) for detecting at least one lateral (y-direction) position of a head of a vehicle occupant with respect to a Headrest of a vehicle seat, wherein the sensor arrangement ( 200 ) a plurality of sub-electrodes ( 210a -D) arranged in a plurality of columns. Sensor arrangement ( 200 ) according to claim 12, characterized in that the sub-electrodes ( 210a -D) are further arranged line-shaped in a plurality of rows. Sensor arrangement ( 200 ) according to one of claims 12 or 13, characterized in that the sub-electrodes ( 210a -D) individually from outside the sensor arrangement ( 200 ) contactable or at least a partial electrode field ( 200 ) are interconnectable. Headrest for a vehicle seat of a vehicle, the headrest having a sensor arrangement ( 200 ) according to one of claims 12 to 14.