DE102006013495A1 - Passenger mass determining method for use during crash fall of vehicle, involves determining belt force acting on passenger by belt force sensor, where value for passenger mass is derived from division of belt force by sum of accelerations - Google Patents

Abstract

The method involves determining vehicle acceleration by using an ESP (RTM: electronic stability control system) sensor (2). The acceleration of a belt strap (16) securing a passenger (102) is determined by a belt rolling angle sensor (3). The belt force, which acts on the passenger is determined by a belt force sensor (4), where a value for the passenger mass is derived from the division of the belt force by the sum of the vehicle acceleration and the belt strap acceleration. Independent claims are also included for the following: (1) a system for determination of the passenger mass of a passenger secured by the safety belt in a vehicle (2) an adaptive seat belt system for a vehicle (3) a computer program with program code units for determining a passenger mass of a passenger secured by a safety belt system (4) a computer program product with program code units for determining a passenger mass of a passenger secured by a safety belt system.

Description

The The present invention relates to a method and a system for Determining occupant mass by a seat belt system secured occupants in a vehicle, especially in the event of a crash. In one embodiment of the invention, by means of this method and this system also determines an occupant acceleration.

A Knowledge of the occupant mass and / or the occupant acceleration of a seat belt occupants secured in a vehicle by a seat belt system, In particular motor vehicle, in particular in the event of a crash to different Purposeful. This data can For example, be used to a regulated restraint system (regulated or adaptive seat belt system, airbag) optimal to vote on the inmates. This allows the protection potential of the restraint system be improved by according to the different personal Properties (occupant mass, occupant acceleration) the restraint system is regulated. In this way, a light little woman can be with lower forces through the restraint system be caught as a big one heavy man being held back by the seat belt with higher forces must become. Unlike non-adaptive restraint systems where the restraining forces are not can be controlled let yourself with such control strategies the risk of injury for protection of the occupant decrease significantly.

A possible The rule strategy for reducing the risk of injury would be, for example, the Inmates as possible low and constant forces while to suspend a crash. This could be a release of the webbing of the seat belt system or a deceleration of the webbing of the Safety belt system be made such that as setpoint one possible Constant occupant acceleration results. For this it is necessary to know the actual value of the occupant acceleration. At known Occupant mass would let in addition or alternatively the belt force during to fix a crash. However, the knowledge of the occupant mass is also for others Applications make sense.

in the In the prior art, the measurement of occupant mass and occupant acceleration is difficult consuming and also inaccurate and usually only with great effort in one Vehicle feasible. Without restriction of generality in the present application as an example of a vehicle a motor vehicle serve.

The following known measuring methods can be used to measure the acceleration of an occupant (in particular during a crawl). These methods work by measuring occupant position, which results in occupant acceleration as a second derivative over time:
As optical measuring methods are indoor cameras that can recognize objects through image processing, or stereo cameras that can detect spatial structures known. In this case, brands can be attached to the strap for simplicity, which are recognized by the cameras. It may be visible to the occupant or invisible brands. The cameras can also detect human structures (face or outer surface of the occupant). Furthermore, by triangulation of radio-transmitted sensor signals, the position of the belt and thus the occupant can be determined. Finally, for example, RFID chips can be excited by a field for transmission. If at least one such chip is located on the webbing, the emitted signals can be evaluated by triangulation and the spatial position of the occupant can be determined.

In an older, not pre-published Registration of the applicant is proposed to accelerate the occupant via a to determine existing on the webbing acceleration sensor.

The Measurement methods known from the prior art are based on the Detecting the occupant position, resulting from a change in occupant position an occupant acceleration can be calculated. This appears It makes sense to use multiple sensors or marks on a webbing too to distribute. Apart from the aforementioned application of the applicant is an immediate measurement of occupant acceleration - so far apparent - not suggested Service.

to Determining the occupant weight are very elaborate mechanics known, for example, about Seat mats, force sensors on the seat or similar work. For example A seat mat is produced to reduce the severity of an occupant over the seat Estimate seatprint and to implement a child seat recognition. A determination the occupant mass without specially attached to the seat sensors is - so far apparent - not known.

Of the The present invention is therefore based on the object, in particular in the event of a crash the occupant mass and / or the occupant acceleration of a seat occupant secured in a vehicle by a seat belt system with sufficient accuracy and preferably without any time delays to determine.

This object is achieved by a method according to claim 1 or 2 and solved by a system according to claim 8 or 9. A safety belt system with such a system is the subject of claim 15. A computer program and a computer program product for implementing the method are given in claims 16 and 17, respectively. Advantageous embodiments emerge from the respective subclaims and the following description.

According to the invention, a vehicle _acceleration a _WKS (WKS = World Coordinate System) is first determined by means of a sensor in the vehicle _interior , with this vehicle acceleration relating to the stationary environmental coordinate system. With the aid of a sensor, which is preferably arranged on the safety belt system, an acceleration a _CKS (CKS = Car Corridinate System) of the occupant securing webbing is determined. In a further step, a belt force F _{belt is} determined by means of a belt force _sensor , which acts on the occupant. To determine the occupant mass, the belt force is then divided by the sum of vehicle acceleration and acceleration of the belt, from which a value for the occupant mass is derived.

According to the invention can by means of said sensors and a corresponding arithmetic unit to make the necessary calculations in a simple way in particular while a crash the occupant mass in real time with good accuracy determined or estimated become.

As a sensor for the measurement of a vehicle acceleration a _WKS , an ESP sensor, which is often already present in motor vehicles, is preferably used. With the help of such sensors, a breaking of the vehicle in fast cornering is prevented in the context of the so-called electronic stability program (ESP). It makes sense to arrange the (ESP) sensor for measuring the vehicle acceleration as possible in the passenger compartment, since in particular in the event of a crash, the passenger compartment in which the occupant is located may be exposed to other accelerations than the other vehicle parts. The (ESP) sensor should be designed so that it is not only able to detect the regular dynamic acceleration (up to approx. 2 g), but also the much higher accelerations of up to 80 g occurring in the event of a crash.

When additional component needed the invention provides a sensor for measuring and determining a Gurtbandbeschleunigung. Here, it makes sense to provide a sensor that the Abwickelbe movement of the Webbing senses. Such a belt pull-out sensor is advantageously integrated in the seat belt system. For example, a Gurtrollenwinkelgeber, the detects an angular movement of the belt reel. The acceleration of the webbing is from the temporal change of the webbing extension calculated by, for example by means of a microcontroller second derivative of the webbing extension is formed over time. In the case of a Gurtrollenwinkelgebers, the angular velocity the belt reel can detect results with the help of Gurtrollenradius the belt pullout speed, from which by simple temporal Differentiation a Gurtbandbeschleunigung can be determined.

It it should be noted that the determination of the belt acceleration the accuracy of the determination of the occupant mass according to the invention the strongest influencing size is, because the occupant acceleration signal is very noisy in practice is. As explained below, can still be good values for derive the occupant mass.

Instead of a sensor for determining the vehicle acceleration and a another sensor for determining the Gurtbandbeschleunigung can in the context of the present invention alternatively also a single sensor used, which is already the sum of vehicle acceleration and Gurtbandbeschleunigung detected. This can be in the description introduction be already mentioned acceleration sensor, preferably on the webbing is present and the occupant acceleration as an absolute size over the fixed the vehicle surrounding inertial system measures. This occupant acceleration namely, gets together from the vehicle acceleration (acceleration of the vehicle relative to the fixed inertial system) and the Gurtbandbeschleunigung (equal the occupant acceleration against the non-stationary inertial system of the passenger compartment of the vehicle). Therefore the subsequent one Determining the occupant mass anyway the sum of vehicle acceleration and webbing acceleration is needed Such a sensor can be used to determine occupant acceleration the sensors for determining the vehicle acceleration or the Replace webbing acceleration.

When additional component needed The invention relates to a belt force sensor, which occurs in the webbing personnel measures. These forces act on the secured by the seat belt occupants. It is appropriate to the Belt force sensor, for example, to be attached to the buckle.

Both Concepts are based on the common idea, from an acceleration a vehicle occupant relative to the "inertial system" in which the Vehicle is at almost constant speed, to determine its mass.

In In the present application, the terms "measuring", "determining", "determining", "deriving" and "estimating" in equivalent Be used way. It is clear to the person skilled in the art that sensors in first of all deliver measuring signals which require a later evaluation. ever After realization of the evaluation unit (arithmetic unit), the Measured values directly processed and from this a value for the occupant mass, as explained below, derived from the measured values, the corresponding variables (vehicle acceleration, Gurtbandbeschleunigung, belt force) determines, from which subsequently a Value for the occupant mass is derived. Furthermore, it is clear to the person skilled in the art that the won sizes no represent exact values but measured values or obtained from measurements Sizes that naturally are subject to (measurement) errors.

From the belt force, the (calculated) Gurtbandbeschleunigung and the vehicle acceleration, the mass of the occupant is now derived as follows: F belt = m inmate · (A ESP + a CKS )

In the above equations, a is _WKS = a _ESP when an ESP sensor is used to measure vehicle acceleration.

The Determination of the occupant mass is preferably carried out in the low frequency range. For this purpose, advantageously, a filter in the corresponding arithmetic unit provided, the medium and high frequency ranges from the obtained Signal for the occupant mass filters out. However, this filtering leads to good results, given the mass of the inmate as a very constant and unalterable size assumed can be.

Consequently, after filtering the signal, the occupant mass m _{inmate is determined} with sufficient accuracy. This value can now be further processed to determine the occupant acceleration.

In a particularly preferred embodiment of the invention is therefore from the occupant mass m _occupant and the belt force F _belt , which is measured by the belt force sensor, calculated back to the occupant acceleration. It results to:

Regarding the Determination of the occupant acceleration is at this point on it pointed out that in the present application, the method and the system for determining the occupant acceleration also independent of Method and system for determining occupant mass under protection can be provided if indeed the occupant mass is otherwise determined. In this case will from the measured by means of a Gurtkraftsen sors belt force and a value (calculated, for example, from the occupant weight) for the Occupant measures an occupant acceleration according to the above context calculated.

In order to can according to the invention the occupant mass and the occupant acceleration in a vehicle crash or more generally whenever necessary for the invention Components provide signals such. B. in the case of full braking, bypassing the problems encountered in the prior art become. In particular, there is no immediate measurement of occupant mass necessary. The occupant acceleration can be safe, highly dynamic and very accurately, on most motor vehicles without any further hardware, be determined.

Furthermore, the invention relates to a safety belt system with an inventive system for determining the occupant mass. In addition, it should be noted that the said system can also be used to determine the occupant acceleration (as stated above). Safety belt systems per se are known from the prior art. One possible embodiment of an adaptive safety belt system is in the prior notification DE 10 2005 041 101.0 the applicant described.

This safety belt system comprises an actuatable by an actuator (electric motor) brake assembly (wedge brake) for braking a movement of the webbing. This brake assembly is designed as a self-energizing arrangement of the actuating force generated by the actuator. Furthermore, the actuator is connected to an electronic control unit, which is set up to control the actuator as a function of at least one occupant-specific and / or situation-specific parameter. Such parameters represent, for example, the occupant mass (m _occupant ) the seating position of the occupant, the speed of the motor vehicle, a crash pulse in the event of a crash, or parameters characterizing the surrounding situation (eg temperature, road condition, nature of an obstacle). Depending on one or more of these Parameter determines the electronic control unit, for example, a time-dependent setpoint characteristic, according to which the Process of decelerating the unwinding movement of the webbing from the belt reel (or more generally the output of the webbing) is controlled. Such an adaptive safety belt system can optimally regulate in particular the vehicle occupant restrained belt force as a function of light or heavy vehicle occupants, so that on the one hand excessive force effects of the belt with the consequence of an increased risk of injury to the head and chest area are reduced and on the other hand the risk that a person crashes in a crash on the steering wheel is minimized.

is Such an adaptive safety belt system with a system according to the invention for determining occupant mass and / or occupant acceleration equipped, it is possible, for example, the deceleration of the webbing movement or the output of the webbing depending on the particular Occupant mass and / or occupant acceleration. An example Such an adaptive safety belt system is related with the embodiments discussed in more detail become.

Around the inventive method for determining occupant mass and / or occupant acceleration preferably to automate efficiently, it makes sense to use this procedure to implement a computer program, in particular an arithmetic unit of the system according to the invention is started and executed. This can be for the determination of the belt acceleration from the corresponding Sensor data, such as the data of Gurtrollenwinkelgebers, as well as for determining a value for the occupant mass from the belt force, the vehicle acceleration and the Gurtbandbeschleunigung and finally to determine the occupant acceleration from the belt force and the determined value for the occupant mass respectively its own arithmetic unit be present or preferably one and the same arithmetic unit perform these calculations.

The Computer program can be used as a computer program product on data carriers, such as CD-ROMs, EEPROMs or even be stored in the form of flash memories, or else as a pure computer program over various computer networks (such as intranet or internet) in the main memory be downloadable. As a computer program and computer program product Microcontroller programs or microcontroller program products are also understood.

in the The following are the invention and its advantages in embodiments, which by the attached Figures are illustrated, closer explained become.

1 1 schematically shows an occupant in a passenger compartment secured by an adaptive safety belt system,

2 shows schematically a flow chart for carrying out a method according to the invention,

3 shows a relevant section of an adaptive safety belt system, as it can be used together with the present invention, in longitudinal section,

4 shows a plan view of a wedge assembly, which in the in 3 used seat belt system is used, and

5 shows a representation as in 1 as an alternative embodiment.

1 schematically shows an occupant 102 in a passenger compartment 108 viewed from the front. The inmate 102 is characterized by an adaptive safety belt system, of which only schematically the control unit 35 and the webbing 16 is shown, secured. A more detailed discussion of such an adaptive safety system is provided below in connection with FIGS 3 and 4 ,

The inmate 102 is in sitting position on a seat 106 and is through the webbing 16 secured by the adaptive seat belt system. The latter has a Gurtrollenwinkelgeber as part of the system for measuring a belt webbing according to the invention 3 on. Furthermore, in this embodiment for measuring a belt force, a belt force sensor 4 at the belt buckle of the belt 16 attached or integrated there. Finally, as a sensor for measuring the vehicle acceleration is an ESP sensor 2 arranged in the passenger compartment. The arithmetic unit 5 for deriving a value for the occupant mass is part of the control unit in this embodiment 35 the adaptive safety belt system. This allows the determined values for occupant mass and / or occupant acceleration of the control unit to be easily determined 35 can be supplied, which in turn controls or regulates an output of the webbing or a deceleration of the webbing movement in the event of a crash.

Although in 1 the system according to the invention with his Gurtrollenwinkelgeber 3 , his belt force sensor 4 and the arithmetic unit 5 is shown closely linked to the adaptive seat belt system, it is also conceivable in the context of the present invention to solve this system from the adaptive seat belt system. However, in order to ensure a simple, robust and safe construction of such a system and to make optimum use of existing components, it is preferable to To integrate the system according to the invention as far as possible in an existing adaptive safety belt system.

The following is based on 2 the sequence of a method according to the invention for determining the occupant mass and the occupant acceleration using the in 1 shown system will be explained in more detail. The described sequence corresponds to the algorithm that the claimed computer program must execute in order to implement the method according to the invention.

In the case of a vehicle crash considered in the present case, firstly the occupant mass and then the occupant acceleration are to be determined. In step 201 Passenger cell acceleration is detected by the ESP sensor 2 measured (a _ESP = a _WCS ). Parallel to this, in step 202 the Gurtbandauszug measured, for example via the already mentioned Gurtrollenwinkelgeber 3 , Again, parallel to this, in step 203 the belt force by means of the belt force sensor 4 measured. Since usually the Gurtbandbeschleunigung can not be detected immediately, the acceleration of the Gurtbandauszugs must be calculated. This is done in step 204 a temporal differentiation made. Based on the measured distance of the webbing extension a two-fold time derivative is necessary. Based on the speed of the webbing extension a simple time derivative is necessary to come to the acceleration of the webbing extension. On this occasion, it should be noted that the acceleration of the webbing extension corresponds to the acceleration of the occupant with respect to the vehicle interior.

After the step 204 are the quantities necessary for the determination of the occupant mass. First, in step 205 the (absolute) occupant acceleration m _occupant = a _ESP + a _CKS calculated as the sum of the calculated passenger _{cell acceleration} and the belt acceleration by simple summation. In step 206 then a determination or better estimate of the occupant mass m _inmates according to the equation

In practice, due to the noisy Gurtbandbeschleunigungs- or occupant acceleration signal shows a more or less noisy result for the occupant mass in the step 206 , However, since the occupant mass is a very constant variable that can not be changed, a subsequent strong filtering of the signal can cause the occupant mass to step 207 a determination of the occupant mass are made with sufficient accuracy (step 208 ).

In this example, the occupant acceleration should continue to be determined. This is followed by the step 208 Another Step 209 at. The occupant acceleration a _{occupant is} calculated from the one in the step 203 measured belt force F _belt through the in step 208 certain occupant _{mass is} divided into _occupant . In step 210 Thus, the occupant acceleration is determined with sufficient accuracy. The method or the computer program then ends in the step 211 , It should be noted that in the step 210 certain levels of occupant acceleration are far more accurate than the noisy signal from the step 205 , By the preceding determination of the occupant mass (steps 207 and 208 However, the noise can be eliminated so far that the in step 210 Recalculated occupant acceleration represents usable values.

All calculations for determining the occupant mass and / or occupant acceleration are preferably carried out in a computing unit 5 executed the system according to the invention. For this, the signals of the sensors 2 . 3 and 4 via lines or by radio to the arithmetic unit 5 transfer. In 1 is the arithmetic unit as part of a control unit 35 a seat belt system integrated. The values determined according to the invention for the occupant mass and occupant acceleration can be supplied to such an adaptive safety belt system. Such is now on the basis of 3 and 4 described in more detail.

3 shows a longitudinal section of a lying on one side of a rotation axis A portion of a belt retractor 10 for a possible adaptive safety belt system 1 , The belt reel 10 includes a rotationally fixed on a floating shaft 12 arranged belt reel 14 on which a webbing 16 is wound. For winding or unwinding the webbing 16 on or off the belt reel 14 is the wave 12 with the belt roll 14 rotatable about the axis of rotation A.

A brake assembly 17 for decelerating an unwinding movement of the webbing 16 from the belt roll 14 includes a brake disc 18 coaxial to the belt reel 14 rotatably on the shaft 12 arranged and thus together with the belt reel 14 is rotatable about the axis of rotation A. A first carrier part 20 has a first section 20 ' on, which is essentially parallel to the brake disc 18 extends and on its the brake disc 18 facing side, a first friction element 22 wearing. A second section 20 '' of the first carrier part 20 extends substantially perpendicular to the first section 20 ' around the outer circumference of the brake disc 18 , The first carrier part 20 is by means of a in 3 not shown bearing along the axis of rotation A slidably mounted and rotatable about the axis of rotation A.

At its outer periphery is the second section 20 '' of the first carrier part 20 with an external toothing 24 provided with an external toothing 26 a gear 28 interacts. The gear 28 is non-rotatable with a motor shaft 30 an electric motor 32 connected, the electric motor 32 regarding the belt roll 14 positioned radially outboard and on one the belt reel 14 comprehensive stationary housing part 34 is attached.

The electric motor 32 is with an electronic control unit 35 connected in turn via a CAN bus system with sensors 36 or signal lines 36 for capturing or transmitting occupant-specific and situation-specific para meters, ie sensors for detection or signal lines for transmitting, for example, the occupant weight, the occupant mass, the occupant acceleration and the occupant position and for example speed sensors, temperature sensors, crash sensors, acceleration sensors, centrifugal force sensors, etc. is in communication. The sensors 36 can anyway in one with the belt retractor 10 equipped motor vehicle, for example, be used to control the brake system sensors. Alternatively, the sensors can 36 but also separate, only with the electronic control unit 35 of the belt retractor 10 be connected sensors. signal lines 36 are in particular those of the arithmetic unit 5 of the system according to the invention, via the values of the occupant mass and acceleration to the control unit 35 be transmitted.

A plurality of first wedges 38 is about an inner circumference of the second section 20 '' of the first carrier part 20 distributed at the second section 20 '' of the first carrier part 20 attached. One of the number of first wedges 38 corresponding number of second wedges 40 is at one of the brake disc 18 remote outer surface of a stationary and with the housing part 34 connected second carrier part 42 attached. The first and second wedges 38 . 40 are oriented so that their oblique wedge surfaces 46 . 48 opposite and extend substantially perpendicular to the axis of rotation A.

On his the brake disc 18 facing side carries a first section 42 ' the second carrier part 42 which is essentially parallel to the brake disc 18 extends, a second friction element 22 ' , To set a distance between the first section 20 ' of the first carrier part 20 and the first section 42 ' the second carrier part 42 is a return spring 44 provided, the ends of which are at the first section 20 ' of the first carrier part 20 or one substantially perpendicular to the first section 42 ' extending second section 42 '' the second carrier part 42 support.

The following is the function of the belt retractor 10 explained. In normal operation of the belt retractor 10 will the webbing 16 by turning the shaft 12 and the non-rotatably associated belt reel 14 about the axis of rotation A on the belt reel 14 on or off the belt reel 14 settled. The brake disc 18 , which also rotatably on the shaft 12 is arranged, upon rotation of the shaft 12 also rotated about the rotation axis A.

If the driver assistance system or a corresponding sensor 36 , such as a crash sensor, detects a dangerous situation or imminent crash controls the electronic control unit 35 first - if present - a belt tensioner, whereupon the actuating mechanism of the belt tensioner rotation of the shaft 12 and thus the belt roll 14 and the brake disc 18 about the axis of rotation A causes. This will make the webbing 16 on the belt roll 14 wrapped and the webbing 16 tight-fitting on the body of the vehicle occupant.

In the crash itself is first caused by the belt tensioner rotational movement of the shaft 12 , the belt roll 14 and the brake disc 18 as a result of the webbing 16 stopped acting force. To a rotation of the shaft 12 , the belt roll 14 and the brake disc 18 in the opposite direction and thus unwinding of the webbing 16 from the belt roll 14 To prevent, then the electric motor must 32 from the electronic control unit 35 be operated.

The electronic control unit 35 In an advantageous embodiment, for this purpose, a characteristic curve may be specified which is selected such that the occupant is preferably braked constantly with respect to the fixed reference system of the vehicle environment. To do this, it is necessary to know the current speed of the vehicle in the event of a crash. Furthermore, the available flight path must be determined. These two quantities are determined by means of the sensors shown 36 , to which also cameras installed in the vehicle can be counted, determined. Furthermore, the electronic control unit 35 from the sensors 36 Receive environmental parameters and / or system-internal parameters or calculate them from the sensor values. One advantage is that the nominal values of the characteristic curve can be specified immediately before and also during the crash. In accordance with this characteristic, the control unit controls 35 the electric motor 32 on, according to the deceleration of the unwinding movement of the webbing 16 from the belt roll 14 causes. The current acceleration values of the occupant 102 receives the control unit 35 preferably from a computing unit 5 of the system according to the invention. Thus, a regulation to the desired acceleration values is possible.

This in 3 illustrated adaptive safety belt system 1 represents a preferred safety belt system for the present invention. As already mentioned, however, the present invention is not limited to such a safety belt system.

When operating the electric motor 32 becomes a rotation of the motor shaft 30 clockwise over the gear 28 on the first carrier part 20 is transmitted. The first carrier part 20 thus becomes clockwise about the axis of rotation A relative to the second carrier part 42 twisted. This causes the sloping wedge surfaces 46 at the second section 20 '' of the first carrier part 20 fastened first wedges 38 on the sloping wedge surfaces 48 the at the second support part 42 set second wedges 40 accumulate, causing the first carrier part 20 against the force of the return spring 44 axially to the brake disc 18 out, that is in 3 is shifted to the left, so that the first friction element 22 to the brake disc 18 invests.

To better illustrate the effect of the first and second wedges 38 . 40 is in 4 a plan view of a wedge assembly with a first and a second wedge 38 . 40 shown. The first and the second wedges 38 . 40 are arranged so that the oblique wedge surface 46 of the first wedge 38 the oblique wedge surface 48 of the second wedge 40 is opposite. A slope P of the wedge surfaces 46 . 48 is determined in each case by a wedge angle α. One through the interaction of the first and second wedges 38 . 40 caused axial displacement d of the first carrier part 20 is determined according to the formula d = φ × P / (2 × π) where φ is the angle of rotation of the first carrier part 20 about the axis of rotation A is.

Although the in 4 shown wedge assembly has a first and a second wedge 38 . 40 includes, the second wedge 40 be replaced by another suitable device, such as a bolt, which is a sliding or rolling support of the first wedge 38 allows. In addition, instead of in 4 shown wedge assembly and a ball / ramp arrangement are used.

When the first friction element 22 to the brake disc 18 applies, the brake disk 18 due to the floating bearing of the shaft 12 together with the first carrier part 20 in the direction of the second carrier part 42 that is in 3 moved to the left. As a result, the brake disc sets 18 almost without delay also to the second friction element 22 ' at.

At the in 3 shown belt retractor 10 form the first carrier part 20 , the second carrier part 42 as well as the first and second wedges 38 . 40 a self-boosting arrangement, that is, that of the electric motor 32 over the gear 28 initiated actuating force is automatically amplified without further forces to be introduced from the outside.

5 schematically shows an occupant 102 in a passenger compartment 108 viewed from the front. The inmate 102 is through an adaptive safety belt system 1 of which only schematically the control unit 35 , the brake assembly 17 and the webbing 16 is shown (see 3 ), secured. A detailed discussion of an example of such an adaptive safety belt system has been made in the context of 3 and 4 given.

The inmate 102 is in sitting position on a seat 106 and is through the webbing 16 secured by the adaptive seat belt system. Between the upper chest area and the abdominal area of the occupant 102 , preferably at a location of the webbing 16 that are typically on the occupant while driving 102 is present, there is an acceleration sensor 6 , The acceleration sensor 6 is integrated in the webbing. The acceleration sensor 6 thus makes movements of the occupant 102 in the same way with, so that the acceleration sensor 6 the acceleration of the occupant 102 absolute, ie relative to the stationary inertial system (vehicle environment) surrounding the vehicle.

Furthermore, in this embodiment for measuring a belt force, a belt force sensor 4 at the belt buckle of the belt 16 attached or integrated there. The arithmetic unit 5 for deriving a value for the occupant mass is in this embodiment again part of the control unit 35 of the adaptive safety belt system (compare the embodiment according to 1 ).

In this embodiment, the data of the acceleration sensor 6 over a radio link 37 to the arithmetic unit 5 transmitted. In the same way, the measured data of the belt force sensor 4 by radio to the arithmetic unit 5 be transmitted. Of course, alternatively or additionally, measurement data transmissions by line are possible.

It is also possible to use several sensors 6 provide, for example, where the webbing over the upper body of the occupant and over the legs of the occupant 102 extends. In this way, several acceleration sensors can 6 in striking areas of the occupant 102 are located so that movements of different body parts can be detected. This allows a more precise detection of the acceleration situation of the occupant. In particular, different crash profiles (spin, overturning, frontal crash, etc.) can thereby also be detected. Furthermore, several sensors allow 6 also an evaluation of the data regarding fault detection due to the existing redundancy.

Furthermore, it may be advantageous, in particular when using a radio link 37 if an activation of the arithmetic unit 5 only then takes place when a certain acceleration threshold is exceeded. As a result, energy can be saved, so that the acceleration sensor 6 can be operated with the lowest possible energy consumption. The same applies, of course, for the other sensors mentioned 2 . 3 and 4 (see. 1 ). Thus, for example, only in the event of a crash, typically in acceleration over 2 to 3 g, the radio link 37 activated and data to the arithmetic unit 5 be transmitted.

It should be expressly noted that the present case in connection with 5 discussed embodiments in an analogous manner to the embodiment according to 1 can be transmitted. The same applies to the opposite case.

For determining the occupant mass according to the invention, in this embodiment, the occupant acceleration with respect to the stationary vehicle environment by means of the occupant acceleration sensor 6 measured. Such acceleration sensors are known per se. Capacitive or piezoresistive acceleration sensors are known and available on the market. In piezoresistive acceleration sensors, a piezoceramic sensor plate converts dynamic pressure fluctuations into electrical signals that can be further processed accordingly. The pressure fluctuation is generated by a seismic mass coupled to the piezoceramic (usually silicon), which then acts on the piezoceramic disk when the overall system accelerates. There are 1D, 2D and 3D acceleration sensors. The size of these sensors is in the millimeter range. Another possibility is the capacitive measurement of the acceleration, which uses an extended plate capacitor, which is divided into two partial capacitors by an additional electrode plate. For this purpose, a mass plate is etched on two small silicon springs (silicon legs) by means of bulk technology. Due to the respective deflection with positive or negative acceleration, a change in capacitance can be measured and evaluated.

For power supply of the acceleration sensor 6 and the other sensors 2 . 3 and 4 (See embodiment according to 1 ) can be provided advantageously rechargeable batteries. Furthermore, it is possible and advantageous if the sensors electrical lines are laid for Spannungsver supply. In the case of the acceleration sensor 6 can in the webbing 16 be woven electrical lines for power supply. Alternatively, an inductive coupling is possible and advantageous. With such an inductive coupling, the sensor can obtain the necessary electrical energy from the electric field. Thus, no lines are required, which can be exposed to high loads, especially in the automotive sector.

To determine the occupant mass according to the invention, the belt force is measured by means of the belt force sensor in a second step parallel to the first step of measuring the occupant acceleration. For this purpose, the embodiment according to 1 directed.

After these steps, the necessary for the determination of the occupant mass sizes a _occupant and F _{belt are} available. In a next step, this is followed by a determination (or better estimation) of the occupant mass a _occupant according to the equation

There it is in the occupant mass to a very constant and unchangeable Size acts, can through a subsequent Filtering the signal of the occupant mass in a next step Determination of occupant mass from the noise in practice Signals of the belt acceleration and the occupant acceleration be made with sufficient accuracy.

As in the embodiment according to 1 has already been described in detail in this embodiment, following the determination of the occupant mass turn back to the occupant acceleration, which is determined from the belt force F _belt , which is divided by the specific occupant mass m _occupant . As a result, as a rule, the occupant acceleration a _{inmate can be determined} with sufficient and higher accuracy than it can be determined by the direct measurement with the acceleration sensor 6 results.

1

seat belt system

2

Sensor, ESP sensor

3

Sensor, Gurtrollenwinkelgeber

4

belt force sensor

5

computer unit

6

Sensor, Occupants accelerometer

10

retractor

12

wave

14

belt roller

16

webbing

17

brake assembly

18

brake disc

20

support part

20 ', 20' '

first Section, second section

22

first friction

22 '

second friction

24

external teeth

26

external teeth

28

gear

30

motor shaft

32

electric motor

34

stationary housing part

35

control unit

36

Sensor, signal line

37

radio link

38

first wedge

40

second wedge

42 42 ', 42' '

second Supporting part, first section, second

section

44

Return spring

46

wedge surface

48

wedge surface

102

inmate

106

vehicle seat

108

passenger compartment, Vehicle interior

Claims (17)

Method for determining occupant mass (m _occupant ) by means of a safety belt system ( 1 ) secured inmates ( 102 ) in a vehicle, characterized in that by means of a sensor ( 2 ) a vehicle acceleration (a _WKS ) is determined by means of a sensor ( 3 ) an acceleration (a _CKS ) of the occupants ( 102 ) securing webbing ( 16 ) and determined by means of a belt force sensor ( 4 ) the belt force (F _belt ) is determined on the occupants ( 102 ), wherein from the division of the belt force (F _belt ) by the sum of vehicle acceleration (a _WKS ) and belt acceleration (a _CKS ) a value for the occupant mass (m _occupant ) is derived. Method for determining occupant mass (m _occupant ) by means of a safety belt system ( 1 ) secured inmates ( 102 ) in a vehicle, characterized in that by means of a sensor ( 6 ) an occupant acceleration (a _occupant ) with respect to the stationary vehicle environment is determined and by means of a belt force sensor ( 4 ) the belt force (F _belt ) is determined on the occupants ( 102 ), wherein from the division of the belt force (F _belt ) by the occupant acceleration (a _occupant ) a value for the occupant mass (m _occupant ) is derived. Method according to claim 1, characterized in that as a sensor ( 2 ) to determine the vehicle acceleration (a _WKS ) an ESP sensor is used. Method according to claim 1 or 3, characterized in that the sensor ( 2 ) for determining the vehicle acceleration (a _WKS ) in the passenger compartment ( 108 ) is arranged. Method according to one of claims 1, 3 or 4, characterized in that a belt extension by means of a Gurtrollenwinkelgebers ( 3 ) as a sensor ( 3 ) and from this measurement the acceleration (a _CKS ) of the webbing ( 16 ) is determined. Method according to one of Claims 1 to 5, characterized in that the value derived for the occupant mass (m _occupant ) is heavily filtered. Method according to one of Claims 1 to 6, characterized in that from the determined belt force (F _belt ) and the determined value for the occupant mass (m _occupant ), an occupant acceleration (a _occupant ) is _recalculated according to the relationship m _occupant = F _belt / m _occupant becomes. System for determining occupant mass (m _occupant ) by a seatbelt system ( 1 ) secured inmates ( 102 ) in a vehicle, characterized by a vehicle interior ( 108 ) arranged sensor ( 2 ) for determining a vehicle acceleration (a _WKS ), a vehicle interior ( 108 ) arranged sensor ( 3 ), with the help of which an acceleration (a _CKS ) of the occupants ( 102 ) securing webbing ( 16 ), a belt force sensor ( 4 ) for determining a force acting on the occupant belt force (F _belt ) and by a computing unit ( 5 ) for deriving a value for the occupant mass (m _occupant ) from the division of the belt force (F _belt ) by the sum of vehicle acceleration (a _WKS ) and belt acceleration (a _CKS ) System for determining occupant mass (a _occupant ) by a seatbelt system ( 1 ) secured inmates ( 102 ) in a vehicle, characterized by a vehicle interior ( 108 ), in particular on the webbing ( 16 ) arranged sensor ( 6 ) for determining an occupant acceleration (a _occupant ) with respect to the stationary vehicle environment, a belt force sensor ( 4 ) for determining a force acting on the occupant belt force (F _belt ) and by a computing unit ( 5 for deriving a value for the occupant mass (m _occupant ) from the division of the belt force (F _belt ) by the occupant acceleration (a _occupant ) System according to claim 8, characterized in that the sensor ( 2 ) is designed to determine the vehicle acceleration (a _WKS ) as an ESP sensor. System according to claim 8 or 10, characterized in that the sensor ( 2 ) for determining the vehicle acceleration (a _WKS ) in the passenger compartment ( 108 ) is arranged. System according to one of claims 8, 10 or 11, characterized in that for measuring a belt webbing a Gurtrollenwinkelgeber ( 3 ) as a sensor ( 3 ) on the seatbelt system ( 1 ) is provided and by means of a computing unit ( 5 ) from the temporal measurement of the belt webbing acceleration of the webbing ( 16 ) is determined. System according to one of claims 8 to 12, characterized in that in the arithmetic unit ( 5 ) a filter for deriving a value for the occupant mass (m _inmate ) is provided. System according to one of claims 8 to 13, characterized in that a computing unit ( 5 ) is provided in order to calculate from the determined belt force (F _belt ) and the determined value for the occupant mass (m _occupant ) an occupant acceleration (a _occupant ) according to a _occupant = F _belt / m _occupant . Adaptive safety belt system for a vehicle for the controlled release of an occupant ( 102 ) securing webbing ( 16 ) of this safety belt system ( 1 ) with a system according to one of claims 8 to 14. Computer program with program code means for implementing a method according to one of claims 1 to 7, when the computer program is stored on a computer, in particular on a computer unit ( 5 ) of the system according to one of claims 8 to 14. Computer program product with program code means which are stored on the computer program product and which implement a method according to one of claims 1 to 7, if the corresponding computer program is stored on a computer, in particular on a computer unit ( 5 ) of the system according to one of claims 8 to 14.