DE102005042203B4 - Method and device for determining an impact severity for a safety system of a motor vehicle - Google Patents

Abstract

Method for determining an impact severity (AS) for a safety system (8) of a motor vehicle (2) having a sensor device (4, 5, 6, 7), comprising the following method steps: (S1) Determining a crash type (CT1) on the basis of signals from the sensor device (4, 5, 6, 7) and assigning a first to the crash type (CT1) corresponding impact severity (AS1) at a first time (T1) and assigning at least one of the crash type (CT1) corresponding second impact severity (AS2) to a second Time (T2); (S2) analyzing the signals of the sensor device (4, 5, 6, 7) regarding a change of the crash type (CT1) from the first time (T1) to the second time (T2); (S3) maintaining the second impact severity (AS2) in the absence of a change in the crash type (CT1) or adjusting the second impact severity (AS2) upon occurrence of a change in the crash type (CT1) to the modified crash type (CT2); (S4) determining the current impact severity (AS) by an impact severity detector (12) taking into account the first and second impact severity (AS1, AS2) based on a predetermined criterion; wherein the second time (T2, T2n) is determined by means of a predeterminable time delay; and wherein the second time (T2, T2n) is determined by means of an adjustable timer (14).

Description

STATE OF THE ART

The present invention relates to a method and an apparatus for determining an impact severity for a safety system of a motor vehicle having a sensor device.

Sensor devices for safety systems in motor vehicles consist of sensors in different designs, for example as acceleration sensors, for the function of crash or impact sensors. You will u. a. used for detecting side impacts, front crashes or for the detection of crash severity or impact severity in the front of a vehicle for years.

Safety systems in motor vehicles include, for example, known retaining means such as airbags, belt tensioners and the like with associated control devices.

The triggering of the retaining means is carried out, for example, depending on the crash type and the relative speed between the motor vehicle and the impact object, wherein the impact severity at the right time can only be present when the crash type is present at the required time of the impact severity. An assignment of relative speed and crash type to the impact severity takes place immediately.

However, there are impact situations in which it is necessary that not only a restraining means, but also a second or possibly several restraining means be ignited later, not at all or with a lower restraining effect. For this purpose, a crash type detection is carried out with an associated impact severity assignment, wherein a relative speed is included.

The DE 102 52 227 A1 describes a method for controlling restraint means.

The DE 10 2004 059 908 A1 describes a method and a device for controlling restraint means.

The DE 100 59 426 A1 describes a method for triggering restraint means in a motor vehicle, in which an accident severity is determined by means of sensor signals in order to enable a better control of the restraint means, which are also in stages or continuously switchable. The sensor signals contain data on driving dynamics, accelerations on impact, rollover, braking, etc., as well as on the vehicle environment, for example through predictive sensor technology. Occupant classification takes place independently and is combined with accident severity data prior to release of the restraint.

ADVANTAGES OF THE INVENTION

The method according to the invention and the device according to the invention for determining a collision severity for a safety system of a motor vehicle with a sensor device, in contrast with the features of claims 1 and 5, enable a multistage, flexible impact severity determination that does not only determine a collision severity for a speed-crash-type combination, but also at one or more later times of one or more further impact severity. The calculated impact severity can thus be adjusted during the crash.

This results in the advantage that, in contrast to a fixed time offset of a specified sequence of impact severity, in an initially hard crash type, which develops in its further course as a soft crash type, this is also recognized as a soft crash type and the retaining means accordingly can be triggered less energetically. This is advantageous insofar as possible injuries that can be caused by high-energy retention means are as far as possible avoidable.

The basic idea of the invention is based on the fact that not only one impact severity is assigned to a specific relative velocity / crash type combination but at a later time a second one which corresponds to the triggering of further restraint means. The time interval for later triggering is not fixed, but it is constantly checked within this time interval, whether the need for the initially associated impact severity is still present. This allows for a rebalancing impact output that is at the heart of the invention. This is associated with an advantageous adapted to the situation ignition of the retaining means.

• (S1) Bestimmen eines Crashtyps anhand von Signalen der Sensoreinrichtung und Zuordnen einer ersten zu dem Crashtyp korrespondierenden Aufprallschwere zu einem ersten Zeitpunkt und Zuordnen mindestens einer zu dem Crashtyp korrespondierenden zweiten Aufprallschwere zu einem zweiten Zeitpunkt;
• (S2) Analysieren der Signale der Sensoreinrichtung hinsichtlich einer Änderung des Crashtyps vom ersten Zeitpunkt bis zum zweiten Zeitpunkt;
• (S3) Beibehalten der zweiten Aufprallschwere in Abwesenheit einer Änderung des Crashtyps oder Anpassen der zweiten Aufprallschwere bei Auftreten einer Änderung des Crashtyps an den geänderten Crashtyp;
• (S4) Bestimmen der aktuellen Aufprallschwere durch einen Aufprallschweredetektor unter Berücksichtigung der ersten und zweiten Aufprallschwere anhand eines Kriteriums.

Accordingly, the method according to the invention for determining an impact severity for a safety system of a motor vehicle having a sensor device has the following method steps:

• (S1) determining a crash type based on signals of the sensor device and assigning a first crash severity corresponding to the crash type at a first time and assigning at least one second crash severity corresponding to the crash type at a second time;
• (S2) analyzing the signals of the sensor device with respect to a change in the crash type from the first time to the second time;
• (S3) maintaining the second crash severity in the absence of a change in the crash type or adjusting the second crash severity upon occurrence of a change in the crash type to the changed crash type;
• (S4) Determining the current impact severity by an impact severity detector taking into account the first and second impact severity based on a criterion.

By analyzing the sensor signals in process step ( 2 ) from the first to the second time for determining a possibly changed crash type and an associated adaptation of the impact severity, an advantageously multi-stage determination of the impact severity is achieved. This ensures a particular advantage in the flexibility of the security system.

It is preferred that in method step (S1) signals of at least one impact sensor be used as acceleration signals and a forward-looking sensor as signals of a relative speed between the motor vehicle and an impact object. These are proven sensors and thus advantageous in the application.

It is particularly advantageous that in the method step (S3) when adjusting the second impact severity, the second time is adjusted. Thus, further flexibility in the adaptation to a changing crash type during the crash course is advantageously possible.

In a further embodiment, the second time is determined by means of a predefinable time delay. In this case, it is advantageous that the second time is determined by means of an adjustable timer, since this is available as a simple and proven component or as software.

It is further contemplated that in method step (S4) the impact severity detector takes into account all impact severity, wherein the criterion is maximum formation and / or minimum formation with consideration of the respective current sampling time. By taking into account all impact severity an advantageous reliability is guaranteed.

• – Sensoren zur Bereitstellung von Signalen bei einem Aufprall des Kraftfahrzeugs;
• – ein Steuergerät zur Verarbeitung der Signale, Bestimmung eines Crashtyps und Bestimmung der Aufprallschwere; und
• – Komponenten des Sicherheitssystems des Kraftfahrzeugs.

An inventive device for determining an impact severity for a safety system of a motor vehicle has the following:

• - Sensors for providing signals in an impact of the motor vehicle;
• A control unit for processing the signals, determining a crash type and determining the severity of the impact; and
• - Components of the safety system of the motor vehicle.

• – eine Bestimmungseinrichtung für einen Crashtyp;
• – eine Zuordnungseinrichtung zur Zuordnung einer Aufprallschwere zu dem Crashtyp;
• – eine Speichereinrichtung zur Speicherung von vorgebbaren Datenwerten;
• – einen Aufprallschweredetektor zur Bestimmung der Aufprallschwere; und
• – einen Zeitgeber zur Festlegung von Zeitpunkten.

In one embodiment, it is provided that the control unit has the following:

• A determination device for a crash type;
• An allocation device for assigning an impact severity to the crash type;
• A memory device for storing predefinable data values;
• An impact severity detector for determining the impact severity; and
• - a timer for setting times.

In this case, it is preferable for the sensor device to have at least one impact sensor and one forward-looking sensor.

In one embodiment, the timer has delay elements for determining times, which can advantageously be switched on and / or switched over according to an assignment.

In a preferred embodiment, the timer is designed as a timer, wherein this timer is advantageous, for example, as a software module easily adjustable and changeable.

It is preferred that the determination device, the allocation device, the impact severity detector and the timer are components of a software of the control device, since thus an advantageous space saving and cost-effectiveness are made possible.

In a further embodiment, the control unit is part of a hardware and / or software of a computer device of the motor vehicle.

Advantageous embodiments and further developments of the invention are the dependent claims and the description with reference to the drawings.

DRAWINGS

The invention will be explained in more detail with reference to the embodiments specified in the figures of the drawing.

It shows:

1 a schematic representation of an embodiment of a device according to the invention in a motor vehicle;

2 a block diagram of another embodiment of the device according to the invention;

3a and b is a graphical representation of a first example of crash types and associated impact severity;

4a and 4b a graphical representation of a second example of crash types and associated impact severity;

5 an exemplary flowchart for impact severity determination; and

6 another exemplary flowchart of a method according to the invention.

DESCRIPTION OF THE EMBODIMENTS

1 is a schematic representation of an embodiment of a device according to the invention 1 in a motor vehicle 2 , A coordinate system is used for orientation, where x is the direction of travel of the vehicle 2 , y denotes its width extension and z denotes the vertical axis.

The device 1 consists in this example of a control unit 3 , a sensor device connected thereto 4 to 7 and restraints 9a to 9f , The sensor device is designed as follows: An impact sensor 4 as an acceleration sensor and a predictive sensor 5 , For example, an ultrasonic or radar sensor, in the front region of the motor vehicle 2 , Foresighted sensors may also be cameras or communication means with vehicles in front or, for example, intelligent traffic guidance devices. A right and left side impact sensor 6 and 7 , For example, pressure sensors are in this embodiment also with the control unit 3 connected. Of course, further sensors are conceivable. In a minimal version is the impact sensor 4 and the predictive sensor 5 intended.

As a restraint here are two front airbags 9a . 9b , two side airbags 9c . 9d and two belt tensioners 9e . 9f shown symbolically by the control unit 3 are triggerable and form a security system. A security system may also include other components such as the braking and steering system.

The control unit 3 receives data from the sensors in a particular waveform and calculates the trigger decision for the restraint 9a to 9f ,

In 2 is the control unit 3 in a further embodiment of the device according to the invention 1 symbolically shown in more detail. The impact sensor 4 and the predictive sensor 5 are at inputs of the control unit 3 connected. At its output is the control unit 3 with a security system, not shown, for example, as in 1 , connected. The control unit 3 has a determination device 10 for a crash type CT; an allocation device 11 for assigning an impact severity AS1, AS2 to the crash type CT; a storage device 13 for storing predefinable data values; an impact severity detector 12 for determining the impact severity AS; and a timer 14 establishing times T2, T2n.

The control unit 3 in this example further includes a processor, not shown, in which the algorithm for determining the impact severity based on the of the sensors 4 and 5 delivered signals is executed. The function will be explained below with reference to 5 and 6 described in detail.

Now, based on the 3a . 3b . 4a . 4b a multi-stage impact severity detection described by way of example, as in the device 1 to 1 and 2 is executed in principle.

3a shows a time course of a crash type in different execution. After a first impact contact at time T0, the crash type is first detected as a hard crash type CTh and at a later time as a soft crash type CTw. In such cases, the crash type detected at the beginning of the crash turns out to be too hard, which changes the strength of the release means deployment. In this context, two cases can be distinguished in a multi-level impact severity determination:

3a and 3b show the first possible case. At time T1, the triggering algorithm detects a hard crash type CTh. From this point in time T1, an impact severity AS = ASM (mean impact severity) (see 3b ). At the same time, the timer starts 14 ( 2 ) a time interval with an end time T2. If, up to this point in time T2, the hard crash type CTh continues to be detected in each subsequent scanning step of the sensor signals, the crash will continue to be treated as a hard crash type CTh and the corresponding restraint means will be energized (for example the second airbag stage). At time TS occurs one Change in the course of the sensor signals, resulting in a modified crash type, here the soft crash type CTw. However, this transition takes place at the time TS, which occurs later here than the end time T2. Thus, the now changed crash type has no influence on the further course, since the corresponding retention means have already been fired at the end time T2. In 3b Accordingly, it can be seen that at the end time T2 the impact severity AS is raised to the value 5, which may be provided for example on the basis of the course of the crash type CT.

The second situation is in 4a and 4b shown. It is almost the same situation as in 3a and 3b before, with the difference that now the transition time point TS from the hard crash type CTh to the soft crash type CTw is earlier than the end time T2. The hard crash type CTh detected at time T1 remains until time TS. However, now is the end time T2 only when the hard crash type CTh is no longer detected (ie after the transition time TS). In such a case, it would not be advantageous if the impact severity AS at the end time T2 would jump to, for example, the value ASH2 (impact severity very hard), since then a soft crash type CTw would be interpreted as harder. The retaining means would be activated according to the hard CTh and not the soft crash type CTw. Instead, it is in this case of great advantage, the impact severity AS on the value ASM (impact severity medium) to leave. If there is also a defined end time T2n for the softer crash type CTw, from which the impact severity AS should, for example, jump to the value ASH1 (impact severity hard), the impact severity AS is increased to the value ASH1, provided the soft crash type CTw has been detected by the end time T2n has been. There are two possibilities for the definition of the end time T2n. The first considers the period from transition TS from hard CTh to soft crash CTw. The second considers the period from the detection of the hard crash type CTh.

The method according to the invention for the multi-stage impact severity determination with the function of the components of the control unit will now be described below 3 based on 5 explained.

5 shows an exemplary flowchart that has four paths. For the multi-stage determination of the impact severity is determined by the determination device 10 requires both the relative speed and the acceleration signal from which it determines the crash type CT. This provision is known and will not be explained in detail.

Path 1 shows the immediate output of a first impact severity AS1. Path 2 describes the multilevel second increased impact severity output of AS2. Paths 1 and 2 have a hard crash type CT1 = CTh as starting position. The path 3 represents the determination of a third impact severity CS3 in the detection of a softer crash type CT3 = CTw. The path 4 again refers to the increase of the impact severity to a fourth impact severity CS4.

First, in the multi-stage impact severity determination, a single or possibly multiple impact severity CS with the associated delays T2, T2n (only for first or both first and second airbag stages, for example) is output based on the combination of crash type CT and relative velocity. This takes place in the allocation device 11 of the control unit 3 ,

If only a single impact severity is determined then this should be labeled AS1 or AS3. If two are determined, then the first one is called AS1 and the second one is AS2, and the same applies to AS3 and AS4. The change in the respective path is through a branch 15 shown. The assignment of crash type CT and relative speed to the impact severity can take place, for example, either via case distinctions (IF blocks) or via table access, the necessary data values in the memory device 14 can be specified and also stored changeable. This assignment takes place for each calculation cycle of the algorithm or at each sampling time. For the mapping of crash type CT and velocity on the impact severity various possibilities, such as logical operations, are conceivable.

Then, a multi-stage, flexible impact severity determination, in particular a change in the crash type detection of any crash type CT to a softer crash type CTw will be discussed. This approach must allow the increase to the higher impact severity to be suppressed during the set delay time between the two impact severity AS1 and AS2 if a softer crash type is found during this time course.

One possible approach could be the use of delay elements. For each type of crash, depending on the relative speed, a certain number of delay elements, for example in the timer 14 , present. If an arbitrary type of crash is detected at one time, these receive as input the constant value of the impact severity AS2, the is issued at a later date, provided that the same crash type is available up to this time. If, however, a softer crash type is detected before this point in time, this means a possibly reactivation of delay elements of this softer crash type, whereby a lower constant value AS4 is now set. It must now be ensured that an output of AS2 does not take place and the constant value is reset even before AS4 is output. That is in the 5 symbolized by a dash under the box AS2. This can be done by case discrimination or logical operations. The advantage of this method is that a realization by means of delay elements can be realized independently of the start time of the triggering algorithm. In addition, an extension to an n-stage impact severity determination is also conceivable in that the delayed value of the softer crash type is in turn reset if there is an even softer crash type with multistage impact severity output in the deceleration time.

• 1. Der Start des Timers erfolgt bei der Ausgabe einer ersten Aufprallschwere AS1 mit einem definierten Zeitintervall. Bei einem Wechsel auf einen niedrigen beliebigen Crashtyp CT wird der Timer bis zu einer neuen definierten Zeitspanne laufen.
• 2. Der Start des Timers erfolgt bei der Ausgabe einer ersten Aufprallschwere AS1 mit einem definierten Zeitintervall. Bei einem Wechsel auf einen niedrigen beliebigen Crashtyp CT wird der Timer bis zum Ende einer neu definierten Zeitspanne laufen. Diese Zeitspanne kann abhängig von der ersten Zeitspanne realisiert werden. Die Zeit, die der Timer noch läuft, ist die neue geforderte Zeit abzüglich der Zeit, die für den ersten Crashtyp verstrichen ist. Dieser Fall macht die mehrstufige Aufprallschwereausgabe vorteilhaft flexibel.

An alternative to the just described method with delay elements is the realization of the multi-stage impact severity determination by means of a single timer 14 The timer-based solution has the advantage that the multi-stage impact severity determination can be made very flexible. The realization of a timer is done by means of a counter that counts the number of calculation cycles of the triggering algorithm or the number of sampling steps. The timer increases its value by one after every sampling cycle. The time until the activation of the higher impact severity AS2 is given as a scaled value as a function of the sampling time. If the time of the second impact severity output is reached, ie its end time, AS2 is output. If, on the other hand, an arbitrary low crash type with multi-level impact severity output AS4 is detected before the output of AS2, two possibilities can be differentiated:

• 1. The start of the timer takes place when a first impact severity AS1 is issued with a defined time interval. When switching to a low, arbitrary crash type CT, the timer will run until a new defined period of time.
• 2. The timer is started when a first impact severity AS1 is issued with a defined time interval. When changing to a low, any type of crash CT, the timer will run until the end of a newly defined time period. This period of time can be realized depending on the first period of time. The time the timer is still running is the new requested time minus the time elapsed for the first crash type. This case makes the multi-stage impact heavy issue advantageously flexible.

The assignment of crash type CT and speed to the timer or delay elements can be done by case distinction. An alternative to this are logical links that lead to the corresponding activation.

The impact severity detector 12 merged, as in 5 shown is the results from the different paths. One possible approach is to consider the current sampling time for peak formation, where as in 5 outlined, all impact severity must be considered. There are also other possibilities for a multi-stage output of the impact severity value, such as a minimum formation of the applied impact severity conceivable.

6 shows a further exemplary flowchart of a method according to the invention with explanation of individual method steps. Here, only one path is shown for simplicity.

After occurrence of an impact at a time T0 (see 3 . 4 In a first method step S1, a determination of a crash type CT1 based on the crash signals of the sensor device and assignment of a first crash severity AS1 corresponding to the crash type CT1 to a first time T1 and assignment of at least one second crash severity AS2 corresponding to the crash type CT1 a second time T2.

Then, in a second method step (S2), a further scanning of the signals of the sensor device with respect to a change of the crash type CT1 is carried out until the second time T2, which is also designated as end time T2. This is done, as already explained above, in each sampling step until the end time T2 is reached. This shows the query symbol T = T2.

In a third method step (S3), the second impact severity AS2 is maintained or the second impact severity AS2 is adjusted when the crash type CT1 changes to the modified crash type CT2. This is done by, for example, a comparison within this process step (S3).

In this case, a new impact severity AS2 'is assigned to the modified crash type CT2. Optionally, the end time T2 can be changed to another end time T2n. With these changed values, as shown, the loop is either run through to the end time T2 or to the new end time T2n.

Upon reaching the respective end time T2, T2n, in a fourth method step (S4), a determination is made of the current impact severity AS by an impact severity detector 12 performed as already described above.

The invention is not limited to the embodiments described above, but modifiable in a variety of ways.

For example, it is conceivable that in the scanning loop after 6 It is also queried whether the new modified crash type CT2 does not exist (CT2 = 0?). This is the case when, for example, the impact has not occurred and the triggering signals have been triggered by a fault. Thus, a plausibility check of an impact can be made additionally hereby. In this case, the process jumps back to the beginning (dashed line).

The device 1 can be fully integrated in a vehicle control except for the sensor device, wherein an advantageous space saving is associated with. Of course, a separate setup is just as possible as a combination of software and hardware.

Claims (8)

Method for determining an impact severity (AS) for a security system ( 8th ) of a motor vehicle ( 2 ) with a sensor device ( 4 . 5 . 6 . 7 ), comprising the following method steps: (S1) determining a crash type (CT1) based on signals from the sensor device ( 4 . 5 . 6 . 7 ) and assigning a first collision severity (AS1) corresponding to the crash type (CT1) to a first point in time (T1) and assigning at least one second collision severity (AS2) corresponding to the crash type (CT1) to a second point in time (T2); (S2) analyzing the signals of the sensor device ( 4 . 5 . 6 . 7 with respect to a change of the crash type (CT1) from the first time (T1) to the second time (T2); (S3) maintaining the second impact severity (AS2) in the absence of a change in the crash type (CT1) or adjusting the second impact severity (AS2) upon occurrence of a change in the crash type (CT1) to the modified crash type (CT2); (S4) Determining the Current Impact Severity (AS) by a Impact Impact Detector (FIG. 12 ) taking into account the first and second impact severity (AS1, AS2) based on a given criterion; wherein the second time (T2, T2n) is determined by means of a predeterminable time delay; and wherein the second time (T2, T2n) is determined by means of an adjustable timer ( 14 ). A method according to claim 1, characterized in that in step (S1) signals of at least one impact sensor ( 4 ) as acceleration signals and a predictive sensor ( 5 ) as signals of a relative speed between motor vehicle ( 2 ) and an impact object. A method according to claim 1 or 2, characterized in that in the step (S3) when adjusting the second impact severity (CS2) adjusting the second time (T2, T2n) takes place. Method according to one of claims 1 to 3, characterized in that in the method step (S4) the impact severity detector ( 12 ) all impact severity (AS1, AS2) is taken into account, with a maximum formation and / or minimum formation taking place as a given criterion with a consideration of the respective current sampling time. Contraption ( 1 ) for determining an impact severity (AS) for a safety system ( 8th ) of a motor vehicle ( 2 ), comprising: - a sensor device ( 4 . 5 . 6 . 7 ) for providing signals in the event of a collision of the motor vehicle ( 2 ); A control device ( 3 ) for the processing of the signals, determination of a crash type (CT) and determination of the impact severity (AS); and components of the security system ( 8th ) of the motor vehicle; whereby the control unit ( 3 ) Comprises: a determination device ( 10 ) for a crash type (CT); An allocation device ( 11 ) for assigning an impact severity (AS1, AS2) to the crash type (CT); A memory device ( 13 ) for storing predefinable data values; - an impact severity detector ( 12 ) for determining the impact severity (AS); and - a timer ( 14 ) for determining times (T2, T2n); where the timer ( 14 ) Has delay elements for establishing times (T2, T2n); and where the timer ( 14 ) is designed as a timer. Contraption ( 1 ) according to claim 5, characterized in that the sensor device ( 4 . 5 . 6 . 7 ) at least one impact sensor ( 4 ) and a predictive sensor ( 5 ) having. Contraption ( 1 ) according to claim 5 or 6, characterized in that the determining device ( 10 ), the allocation device ( 11 ), the impact severity detector ( 12 ) and the timer ( 14 ) Components of a software of the control unit ( 3 ) are. Contraption ( 1 ) according to one of claims 5 to 7, characterized in that the control unit ( 3 ) Component of a hardware and / or software of a computing device of the motor vehicle ( 2 ).

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