CN113619520B

CN113619520B - Method for controlling a vehicle occupant protection device in the event of a vehicle collision

Info

Publication number: CN113619520B
Application number: CN202110477801.7A
Authority: CN
Inventors: J·科拉特舍克; M·沃尔肯斯坦
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 2020-05-06
Filing date: 2021-04-29
Publication date: 2023-05-16
Anticipated expiration: 2041-04-29
Also published as: CN113619520A; DE102020205717A1

Abstract

The invention relates to a method (200) for controlling an occupant protection device (115) of a vehicle (100) in the event of a collision of the vehicle. The method comprises a step of reading an acceleration signal (103) and/or an environmental signal (105), a step of ascertaining a crash-specific variable (125) by using the acceleration signal (103) and/or the environmental signal (105) according to a ascertaining rule (123), and a step of substituting the ascertained crash-specific variable (125) for at least one parameter of a predefined model rule (127) to generate a set model rule (128). An ideal activation time point (132) for activating the occupant protection device (115) is determined by using the set model rules. The method further comprises the step of generating a control signal (135) for controlling the occupant protection device (115) by using the desired activation time point (132).

Description

Method for controlling a vehicle occupant protection device in the event of a vehicle collision

Technical Field

The present invention relates to a method and apparatus for controlling an occupant protection apparatus of a vehicle in the event of a collision of the vehicle.

Background

Occupant protection devices (e.g., passive safety restraint devices) provide protection for vehicle occupants from injury in the vehicle. This can be achieved in particular by the action of the seat belt and by a correct control of actuators such as seat belt tensioners and various types of airbags. And in particular when the restraint device is activated at an optimal point in time, optimal protection of the occupant is achieved. The point in time at which the restraint device is activated can generally be determined in such a way that the restraint device is activated precisely when the measured and preprocessed vehicle deceleration signal plotted against time exceeds a predetermined or calculated threshold value.

Disclosure of Invention

Against this background, a method for controlling an occupant protection device of a vehicle in the event of a collision of the vehicle is proposed by means of the solution presented here, a device using this method being further proposed, and finally a corresponding computer program.

Depending on the embodiment, the model system or the model rules for evaluating a specific feature or characteristic of a vehicle collision from the signals of the acceleration sensor and additionally or alternatively a so-called pre-crash sensor may be used in particular for controlling the occupant protection device of the vehicle or for determining the triggering time or the activation time of the occupant protection device (for example a restraint device for passive safety). By using such features, in particular the estimated or measured initial occupant position, an ideal activation time point for activating the occupant protection device can be calculated, for example in real time. The model rules used may simulate a collision of the vehicle with another object, for example, as mass points with springs, respectively, which may represent the stiffness of the vehicle and the counterpart object. The model rules may in particular simulate the time-dependent curve of the acceleration signal in a crash in a sinusoidal manner. From the actually measured acceleration signal, a parameter can be determined that is optimally adapted to the signal to be determined (for example, a sinusoidal signal) on a given signal curve. In this way, in particular with regard to the seat position and the activation duration of the occupant protection device, the ideal triggering time of the occupant protection device or the optimal activation time of the restraint device will again be determined. An approximation method may also be used here, for example. Activation of the occupant protection device may be triggered if a time corresponding to a specific point in time has elapsed from the start of the collision during the collision.

Depending on the embodiment, the activation time point or the triggering time can advantageously be determined directly from the characteristics of the acceleration signal, so that specific accident situations do not have to be explicitly considered. For example, this only needs to be done once during a collision, and the determination of the optimal ignition time point or the ideal activation time point can be carried out independently for each seat position in a simple sequence based on this particular variable. Another advantage is that the determination of the ideal activation time point can be made independently of the determination of the crash severity. In addition, the activation time point can be determined particularly early. Reliable and robust protection of the vehicle occupants can thereby be achieved. The accuracy of determining the activation time point of the occupant protection device or the ignition time point of the passive safety restraint device can also be increased, so that an improvement in the occupant protection of the vehicle can be achieved.

A method for controlling an occupant protection device of a vehicle in the event of a collision of the vehicle is proposed, wherein the method comprises the following steps:

reading an acceleration signal from an interface for a vehicle acceleration sensor and/or reading an environmental signal from an interface for a vehicle environmental sensor;

According to the calculation rule, a collision-specific variable is calculated by using the acceleration signal and/or the environmental signal;

substituting the determined crash-specific variables for at least one parameter of the predefined model rule in order to generate a set model rule, wherein the model rule for modeling the crash uses or has a sinusoidal signal profile that varies with time;

determining an ideal activation time point for activating the occupant protection device by using the set model rule;

generating a control signal for controlling the occupant protection device by using the desired activation time point, wherein the control signal includes an activation command for activating the occupant protection device; and is also provided with

Control signals are provided for output to an interface for an occupant protection device.

The method may be implemented, for example, in software or hardware or in a hybrid form of software and hardware, for example, in a control unit. The vehicle may be a motor vehicle, such as a land vehicle, in particular a passenger car, a truck or other commercial vehicle. The occupant protection device may be a restraint device for passive safety, in particular an airbag. For collisions, an impact may occur between the vehicle and a colliding object, such as at least one other vehicle or obstacle. The operating signal may represent the acceleration of the vehicle, in particular during a collision. The environmental signal may be representative of the surrounding environment of the vehicle. The environmental sensor may have a vehicle camera, radar device, lidar device, etc. The crash-specific variables may vary depending on the crash type, crash severity, etc. Activation of the occupant protection device can be triggered or initiated on the occupant protection device side by use of a control signal.

According to one embodiment, in the substituting step, the variable may be substituted for a parameter representing the product of the assumed amplitude and the assumed angular frequency. The predefined model rule may define the assumed activation time point as the difference between the cubic root of the quotient of the predetermined distance measure and the parameter and the predetermined activation duration of the occupant protection device. Such an embodiment offers the advantage that an exact determination of the optimal activation time point can be made in a simple manner.

In the determining step, the variable may be determined as a quotient of twice the numerically integrated acceleration signal and the square of time according to the first determining rule. The time may represent a time stamp of the respective calculation period or time step. In addition or alternatively, in the determining step, the variable may be determined as a product of the relative speed between the vehicle and the collision object, identified by the environmental signal, and a quotient of the combined stiffness of the vehicle and the collision object and the vehicle mass, in accordance with a second determining rule. Such an embodiment offers the advantage that the crash-specific variable can be determined quickly and reliably by means of the acceleration signal.

In this case, in the substitution step, the variables determined from the first determination rule and the variables determined from the second determination rule can be substituted into the predefined model rule for the parameters independently of one another to generate the set first model rule and the set second model rule. Here, in the determining step, the first activation time point may be generated by using the set first model rule, and the second activation time point may be generated by using the set second model rule. In addition, the ideal activation time point may be determined as a weighted average of the first activation time point and the second activation time point. The weighting factor may depend on the quality of the ambient signal. Such an embodiment provides the advantage that the determination of the ideal activation time point can be made even more robustly and reliably.

Furthermore, in the determining step, a temporary activation time point may be generated in each time step by using the set model rule. Here, if the period of time that has elapsed since the start of the collision corresponds to the temporary activation time point generated in the time step in one time step, the temporary activation time point may be determined as the ideal activation time point. In this way, the actual ideal activation time point can be found in a simple manner.

In addition, in the generating step, the control signal may be generated by using the collision speed of the occupant of the vehicle to the occupant protection device estimated by means of the estimation rule. The evaluation rule can here define the impact speed as an acceleration signal which is integrated in a single way at the ideal activation time point that is substituted in. In this way, the control of the occupant protection device can be modified in an appropriate manner to further enhance the protection effect thereof.

In the determining step, the ideal activation time point may also be determined by series expansion using the set model rule. The expansion coefficient of the series expansion may take into account, in particular, the state of the seat belt buckle and/or the physical properties of the vehicle occupant. The series expansion may be at least a first-order series expansion, and may be, for example, a second order or higher. Thus, the ideal activation time point can be determined in an accurate manner already before this time point is reached.

According to one embodiment, the method may have the steps of: the threshold value of the doubly integrated predefined reference acceleration signal is specified by using the reference rule for the reference collision with a reference variable specific to the reference collision and a reference activation time point specific to the reference collision. In the determining step, an exceeding time point when the doubly integrated acceleration signal exceeds the threshold value can be determined by using the acceleration signal. In this case, in the determination step, the ideal activation time point can be determined by using the set model rule as a correction factor for the determination rule. The determination rule may be defined as a sum of a difference (as a first addend) between the excess time point and the reference activation time point multiplied by the set model rule and the reference activation time point (as a second addend). Such an embodiment offers the advantage that an improvement in the quality of the ignition point in time calculated on the basis of the forward displacement threshold or the so-called ds threshold can be achieved. In particular, complexity, resource consumption and application effort are reduced, and applicability is extended and accuracy in terms of different accident types and accident severity is improved.

In this case, in the determination step, the set model rule may represent a correction factor predefined as a function of the recognized collision type. In this way, the determination of the ideal activation time point can be accelerated and simplified.

In addition, in the determination step, the seat position of the occupant of the vehicle that moves relative to the standard seat position may be considered in the set model rule. The standard seat position may represent a seat position that is as far forward as possible in the vehicle running direction. The displaced seat position may represent, in particular, a seat position that is detected by using an internal sensor signal of the vehicle internal sensor. In this way, an advantageous adaptation of the activation time of the occupant protection device to the occupant position can be achieved for passive safety. This allows the activation time point calculated for the predetermined occupant position to be simply adapted to any other occupant position. It is possible here to determine the optimal activation time point for all other seat positions based on the activation time point for a given seat position. This results in a saving in terms of application effort, for example, since individual applications for different seat positions can be dispensed with, and also in terms of computer resources, since only fewer thresholds have to be stored in memory, and furthermore the occupant protection effect is improved by a higher resolution in the adaptation of the seat positions at the activation time, wherein the number of thresholds that can be used is not limited, and can be used in addition simply for other or all seats in the vehicle and can be determined independently of the accident severity. Another advantage is that the occupant position can also be used directly as an input variable in the determination, so that another threshold query or a number of independent threshold queries for all possible occupant positions can be made superfluous.

The solution described here also proposes a device which is designed to carry out, control or carry out the steps of the variant of the method presented here in a corresponding apparatus. The object on which the invention is based can also be achieved quickly and effectively by this embodiment variant of the device form of the invention.

For this purpose, the device may have at least one arithmetic unit for processing signals or data, at least one memory unit for storing signals or data, at least one interface with the sensor or the actuator for reading sensor signals from the sensor or for outputting data signals or control signals to the actuator, and/or at least one communication interface for reading or outputting data embedded in a communication protocol. The arithmetic unit may be, for example, a signal processor, a microcontroller, etc., wherein the memory unit may be a flash memory, an EEPROM or a magnetic memory unit. The communication interface may be designed to read or output data wirelessly and/or wiredly, wherein a communication interface that can read or output wired data may read or output the data from or into a respective data transmission line, for example, electrically or optically.

In this context, an apparatus may be understood as an electronic device that processes sensor signals and outputs control signals and/or data signals accordingly. The apparatus may have an interface based on hardware and/or software construction. In a hardware-based architecture, the interface may be, for example, part of a so-called ASIC system that contains the various functions of the device. It is also possible that the interface is a separate integrated circuit or at least partly consists of discrete components. In a software-based architecture, the interface may be, for example, a software module that is resident on the microcontroller in combination with other software modules.

In one advantageous embodiment, the device is used to control a vehicle occupant protection device, for example an airbag. For this purpose, the device can access sensor signals, for example, acceleration signals of an acceleration sensor of the vehicle and environmental signals of an environmental sensor. The control is performed by an actuator such as a device, a gas generator, or the like.

An occupant protection system for a vehicle is also proposed, wherein the occupant protection system has the following features:

an occupant protection device; and

an embodiment of the foregoing apparatus, wherein the apparatus and the occupant protection apparatus are signal-transmissible connected to each other.

The device may be advantageously applied or used in combination with an occupant protection system to control the occupant protection device in the event of a vehicle collision. The device may be embodied here as part of a control unit for an occupant protection device.

A computer program product or a computer program with a program code for performing, implementing and/or controlling the steps of a method according to one of the above embodiments is also advantageous, the program code being storable on a machine-readable carrier or storage medium, such as a semiconductor memory, a hard disk memory or an optical memory, and in particular when the program product or program is run on a computer or a device.

In other words, an optimal or ideal ignition time or activation time of the restraint system or of the occupant protection device can thus be determined, in particular in a control unit or device installed in the vehicle, by using the measured acceleration data, wherein, for example, the initial position of the occupant and the severity of the collision can also be taken into account at the same time.

Drawings

The embodiments of the solution presented here are shown in the drawings and are explained in detail in the following description. Wherein:

FIG. 1 illustrates a schematic view of a vehicle having an occupant protection system according to one embodiment;

FIG. 2 illustrates a flow chart of a method for control according to one embodiment;

FIG. 3 illustrates an exemplary graph of an activation time point of an occupant protection device;

FIG. 4 illustrates an exemplary graph of an activation time point of an occupant protection device;

FIG. 5 illustrates an exemplary graph of an activation time point of an occupant protection device;

FIG. 6 illustrates an exemplary graph of an activation time point of an occupant protection device;

FIG. 7 illustrates an exemplary graph of an activation time point of an occupant protection device;

FIG. 8 illustrates an exemplary graph of an activation time point of an occupant protection device;

fig. 9 shows an exemplary diagram of the activation time point of the occupant protection apparatus.

Detailed Description

Before explaining embodiments of the invention in more detail below, the background and advantages of the embodiments will be briefly discussed first.

Common passive restraint devices provide protection for vehicle occupants from injury in the vehicle. This is achieved by the action of the seat belt and the correct control of actuators such as seat belt tensioners and various types of airbags. The occupant is optimally protected only when the restraint or occupant protection device is activated at the desired or optimal point in time. In general, the activation time point of the restraint device is determined, for example, by activating the restraint device just when the measured and preprocessed vehicle deceleration signal, the drop in speed (dv, first integral of acceleration) or the second integral ds of acceleration plotted against time exceeds a predetermined threshold value. In this case, the threshold value is generally set such that, for example, the ignition of the airbag takes place in such a way that the occupant, as a result of a collision, comes into contact with the airbag just at the moment it has completed its inflation. This is the so-called 5 inch rule: if the occupant is in the normal position, the ignition should be performed in such a way that the airbag has inflated when the occupant has moved forward by 5 inches or about 12.5 cm due to a collision. It is implicitly assumed here that the occupant is initially located 12.5 cm from the contact side of the airbag. Another method directly evaluates the second integral (ds) of acceleration. This variable ds represents a measure of the distance travelled by the head of the occupant if it is assumed that the head of the occupant has not been braked by the seat belt or friction action during the initial accident phase. If ds exceeds a predetermined threshold in this case, the triggering of the airbag may be activated. Unlike such a procedure, a specific activation time point or ignition time point can be precisely determined according to the embodiment and deviate only slightly from the optimum value. According to an embodiment, a simple adaptation to a seat position deviating from the standard can also be achieved. According to the embodiment, in particular, passengers in different positions can be optimally controlled independently in a vehicle having different seat positions with a minimum amount of computation. Furthermore, it is possible according to an embodiment that the determined ideal activation time point not only provides an optimal ignition time for the type of accident and the severity of the accident, but also enables an optimal time point for other accident situations to be achieved more precisely than just approximately. Unlike the case where the trigger time point is determined by only the threshold value of the forward displacement ds, according to the embodiment, the deviation from the ideal ignition time point can be minimized for most cases.

Another method for determining the ignition point of a passive safety restraint consists in triggering the activation of the restraint by the preprocessed acceleration signal exceeding a predetermined threshold value, which may depend on the acceleration signal or other variables occurring in the event of a crash. If this threshold value is exceeded, the corresponding restriction device may also be activated immediately. The ignition time (TTF) corresponds to a time point exceeding a threshold value. According to embodiments, with such an approach, complexity may be reduced, applicability may be more easily improved, and resource costs may be reduced. Another approach is to exceed a predetermined threshold based on a second integral (ds) of acceleration. Unlike this approach, according to an embodiment, the ideal activation time point can also be correctly determined without regard to explicit knowledge of the accident severity and the accident type.

According to an embodiment, defining a separate threshold value for each occupant position may also be omitted in order to obtain a correct activation time point. Thus, the effort can be reduced in terms of application, because each threshold value must contain the correct value, in terms of testing, because each threshold value must be tested separately, in terms of resource consumption, because memory space must be reserved for each threshold value, and in terms of accuracy, because typically only as many different seat positions as there are stored thresholds can be distinguished in the control characteristics. Thus, according to the embodiment, control for a single seat position can also be performed for each occupant with an increased amount of effort.

In the following description of advantageous embodiments of the present invention, the same or similar reference numerals are used for elements that are shown in the respective drawings and function similarly, wherein repeated descriptions of these elements are omitted.

FIG. 1 illustrates a schematic diagram of a vehicle 100 having an occupant protection system 110 according to one embodiment. The vehicle 100 is a motor vehicle, such as a land vehicle, a watercraft or an aircraft, in particular a land vehicle, such as a passenger car, a truck or another commercial vehicle. Fig. 1 shows an acceleration sensor 102, an environmental sensor 104, and an occupant protection system 110 of a vehicle 100.

The acceleration sensor 102 of the vehicle 100 is designed to detect an acceleration of the vehicle 100 and to provide an acceleration signal 103 representative of the detected acceleration of the vehicle 100. The environment sensor 104 is designed to detect an environment of the vehicle 100 and to provide an environment signal 105 representative of the detected environment of the vehicle 100. The environmental sensor 104 is designed in particular to be able to detect so-called pre-crash, i.e. the detection of an impending crash. Here, the environment sensor 104 comprises, for example, a vehicle camera, a radar sensor, a lidar sensor or the like, which has a corresponding signal processing device for detecting an impending collision.

The occupant protection system 110 includes an occupant protection device 115 and a device 120 for controlling the occupant protection device 115 in the event of a collision of the vehicle 100. The device 120 and the occupant protection device 115 are connected to each other in a signal-transmittable manner. The occupant protection device 115 comprises, for example, a passive safety restraint device, in particular at least one airbag.

The apparatus 120 has an input interface 121, an input device 122, a deriving device 124, a substituting device 126, a determining device 130, a generating device 134, a providing device 136 and an output interface 139. The reading device 122 is designed to read the acceleration signal 103 from the input interface 121 for the acceleration sensor 102. Additionally or alternatively, the reading device 122 is designed to read the ambient signal 105 from the input interface 121 for the ambient sensor 104. The reading device 122 is furthermore designed to forward the acceleration signal 103 and/or the environment signal 105 to the ascertaining device 124.

The ascertaining device 124 is designed to ascertain the crash-specific variable 125 by using the acceleration signal 103 and/or the environment signal 105 and in accordance with the ascertaining rule 123. The ascertaining device 124 is further designed to forward the ascertained crash-specific variable 125 in the form of a signal to the substitution device 126. The substitution device 126 is designed to substitute the determined collision-specific variables 125 for at least one parameter of the predefined model rules 127 in order to generate the set model rules 128. Here, the predefined model rules 127 assume a sinusoidal signal curve over time for modeling the collision. The substitution device 126 is furthermore designed to signal the set model rules 128 to the determination device 130.

The determination device 130 is designed to determine an ideal activation time point 132 for activating the occupant protection apparatus 115 by using the set model rule 128. The determining device 130 is further designed to forward the determined ideal activation time point 132 in the form of a signal to the generating device 134. The generating device 134 is designed to generate a control signal 135 for controlling the occupant protection apparatus 115 by using the ideal activation time point 132. The control signal 135 includes an activation command for activating the occupant protection device 115. In addition, the generating device 134 is designed to forward the control signal 135 to the providing device 136. The providing device 136 is designed to provide the control signal 135 for output to an output interface 139 for the occupant protection apparatus 115. Thus, the device 120 is designed to output the control signal 135 to the occupant protection device 115 via the output interface 139. The control signal 135 is adapted to cause activation thereof when processed or used by the occupant protection device 115.

Substitution device 126 is designed in particular to substitute a collision-specific variable 125 for a parameter representing the product of the assumed amplitude and the assumed angular frequency. Here, the predefined model rule 127 defines the assumed activation time point as the difference between the cubic root of the quotient of the six times the predetermined distance measure 103 and the parameter and the predefined activation duration of the occupant protection device 115.

According to one embodiment, the calculation device 124 is designed to calculate the crash-specific variable 125 as a quotient of twice the numerical integrated acceleration signal 103 and the square of time according to a first calculation rule. Additionally or alternatively thereto, the determination device 124 is designed to determine the crash-specific variable 125 as the product of the relative speed between the vehicle 100 and the crash object, identified by the environmental signal 105, and the quotient of the combined stiffness of the vehicle 100 and the crash object and the mass of the vehicle 100, in accordance with a second determination rule. The substitution device 126 is optionally designed to substitute the variables 125 determined according to the first determination rule and the variables 124 determined according to the second determination rule into the predefined model rules 127 for the parameters independently of one another in order to generate the set first model rules 128 and the set second model rules 128. Here, the determining device 130 is designed to generate a first activation time point by using the set first model rule 128 and a second activation time point by using the set second model rule 128, and to determine the ideal activation time point 132 as a weighted average of the first activation time point and the second activation time point. The weighting factor of the weighted average here optionally depends on the quality of the ambient signal 105.

According to one embodiment, the determining device 130 is designed to generate a temporary activation time point in each time step by using the set model rules 128. The determination device 130 is designed to determine a temporary activation time point generated in a time step as the ideal activation time point 132 if the time period that has elapsed from the beginning of the collision in the time step corresponds to the temporary activation time point. Additionally or alternatively, according to one embodiment, the determining device 130 is designed to determine the ideal activation time point 132 by using a series expansion of the set model rules 128. The expansion coefficient of the series expansion optionally takes into account the seat belt buckle state and/or the physical properties of the vehicle occupant. Additionally or alternatively thereto, the generating device 134 is designed to generate the control signal 135 by using the impact speed of the occupant of the vehicle 100 on the occupant protection device 115 estimated by means of the estimation rule. The estimation rule defines the impact velocity as the acceleration signal 103 which is single integrated with the substituted ideal activation time point 132.

According to another embodiment, the device 120 is further designed to define the threshold value of the doubly integrated predefined reference acceleration signal by using the reference rule for the reference impact with a reference variable specific to the reference impact and a reference activation time point specific to the reference impact. The determining device 124 is designed to determine an overrun time point at which the doubly integrated acceleration signal 103 exceeds a predetermined threshold value by using the acceleration signal 103. Furthermore, the determination device 130 is designed here to determine the ideal activation time point 132 as a correction factor of a determination rule by using the set model rule 128, which is defined as the sum of the difference (as a first addition) between the overrun time point and the reference activation time point multiplied by the set model rule 128 and the reference activation time point (as a second addition). The set model rules 128 optionally additionally represent correction factors predefined as a function of the type of collision identified.

According to a further embodiment, the determination device 130 is further designed to take into account the seat position of the occupant of the vehicle 100 moving relative to the standard seat position in the set model rules 128. Here, the standard seat position represents a seat position that is as forward as possible in the traveling direction of the vehicle 100. Here, the displaced seat position represents a seat position identified by using an internal sensor signal of an internal sensor of the vehicle 100.

FIG. 2 illustrates a flow chart of a method 200 for control according to one embodiment. The method 200 for controlling may be performed to control an occupant protection device for a vehicle in the event of a collision of the vehicle. Here, the method 200 may be performed in conjunction with or using the apparatus of fig. 1 or similar apparatus. Thus, the method 200 may also be performed in connection with the occupant protection system of FIG. 1 or a similar system, and the vehicle of FIG. 1 or a similar vehicle. The method 200 for controlling includes a reading step 210, a solving step 220, a substituting step 230, a determining step 240, a generating step 250, and a providing step 260.

In a reading step 210, an acceleration signal is read from an interface for a vehicle acceleration sensor and/or an ambient signal is read from an interface for a vehicle ambient sensor. Subsequently, in a determination step 220, a crash-specific variable is determined using the acceleration signal and/or the environmental signal according to a determination rule. The determined collision-specific variables are then substituted in a substitution step 230 for at least one parameter of the predefined model rule in order to generate a set model rule. The predefined model rules assume a time-varying sinusoid for modeling of the collision. Subsequently, in a determination step 240, an ideal activation time point for activating the occupant protection device is determined by using the set model rule. A control signal for controlling the occupant protection device is then generated again in a generation step 250 by using the desired activation time point. The control signal includes an activation command for activating the occupant protection device. Finally, in a providing step 260, a control signal is provided for output to an interface for the occupant protection device.

According to one embodiment, the method 200 for controlling further comprises a prescribing step 205. Here, the defining step 205 may be performed in advance with respect to the obtaining step 220, and in particular, may be performed in advance with respect to the reading step 210. In a defining step 205, a threshold value of the doubly integrated predefined reference acceleration signal is defined here by using the reference rule for the reference collision with a reference variable specific to the reference collision and a reference activation time point specific to the reference collision. Here, in the determining step 220, an exceeding time point at which the doubly integrated acceleration signal exceeds the threshold value defined in the defining step 205 is determined by using the acceleration signal. In addition, in a determination step 240, the ideal activation time point is determined here by using the set model rule as a correction factor of a determination rule defined as the sum of the difference (as a first addend) between the overrun time point and the reference activation time point multiplied by the set model rule and the reference activation time point (as a second addend).

Fig. 3 shows an exemplary diagram 300 of an activation time point of an occupant protection device. Here, the time t in seconds s is plotted on the abscissa axis of the example map 300, and the activation time point or ignition time point TTF in seconds s is plotted on the ordinate axis of the example map 300. In the exemplary diagram 300, a number of graphs are plotted which represent the time of activation or time of ignition TTF versus time t (TTF (t) curve) for each actual crash signal or acceleration signal during a crash. If these curves intersect the line 302 of the actual time, wherein the intersection points are marked out in each case, they each correspond to the correct ignition time or to an ideal activation time point, for example the activation time point mentioned with reference to the above figures.

Fig. 4 shows an exemplary diagram 400 of an activation time point for an occupant protection device. Here, the example graph 400 corresponds to the example graph in fig. 3, except that the graph represents a TTF curve according to a first-order taylor expansion. Where it can be seen that the graph curves are flatter in the vicinity of the intersection with the actual timeline 302. This flattening makes it possible to determine the ideal activation time point or ignition time point with sufficient accuracy even before the actual time is reached. In other words, and with reference to the above-described drawings, an ideal activation time point is determined by using the series expansion (here, first-order taylor expansion) of the set model rule.

Fig. 5 shows an example diagram 500 of an activation time point for an occupant protection device. Here, a collision-specific variable or a parameter k [ m/s3] in seconds is plotted on the abscissa axis of the example map 500, and an actual activation time point or ignition time point "actual TTF" in seconds [ s ] is plotted on the ordinate axis of the example map 500. The contents in example graph 500 represent synthesized data for actual activation time points associated with a collision-specific variable or parameter k, which varies over a range of values. The collision-specific variable or parameter k is, for example, any of the above-mentioned figures.

Fig. 6 shows an example diagram 600 of an activation time point for an occupant protection device. Here, the actual activation time point or ignition time point "actual TTF" in fig. 5 is plotted on the abscissa axis of the example map 600 in units of seconds s, and the activation time point or ignition time point TTF in units of seconds s is plotted on the ordinate axis of the example map 600. A line 602 representing the correct ignition characteristics is also shown.

Fig. 7 shows an example diagram 700 of an activation time point for an occupant protection device. Here, the example diagram 700 corresponds to the example diagram of fig. 6, except that not only the activation time point TTF1 obtained according to the conventional method but also the activation time point TTF2 determined according to one embodiment are shown.

FIG. 8 showsAn example map 800 for an activation time point of an occupant protection device. Here, in seconds s on the abscissa axis of the example graph 800]The activation time point or ignition time point "TTF set as reference is plotted in units _ref ", and plotted on the ordinate axis of the example graph 800 in seconds s]The activation time or ignition time TTF is a unit. A line 802 representing the correct ignition characteristics is also shown. The exemplary graph 800 is populated with actual data of various accident severity, particularly ignition time points determined according to conventional methods.

Fig. 9 shows an example diagram 900 of an activation time point for an occupant protection device. Example plot 900 corresponds to the example plot of fig. 8, except that actual or ideal activation time points for different incident severity obtained in accordance with one embodiment are shown, and another line 904 represents another collision type.

Embodiments will be explained again in general terms and in other expressions with reference to the above-mentioned figures.

Based on the model or according to predefined model rules, the variation of the acceleration signal a (t) 103 over time t can be represented by the following function:

a(t)＝A·sin(ωt)

here, a is the maximum amplitude of the acceleration signal 103, and ω is the angular frequency thereof. The time t is from the beginning of the collision.

By integrating taking into account the initial conditions, the speed decrease dv of the vehicle 100 from the start of the collision and the forward displacement ds of the occupant relative to the vehicle 100 can be calculated. In the latter case, it is assumed that the occupant is moving without force, which represents an approximation available to the occupant's head during the initial collision phase of interest herein.

For dv there is:

for ds there are:

triggering of the restraint or occupant protection device 115 should take place in such a way that the airbag should have been inflated when the forward displacement ds of the occupant has just passed the distance deltas to the occupant protection device 115, for example to the airbag. Whereby the following function applies to the distance dimension deltas:

Since the activation or ignition of the occupant protection device 115 should generally take place early in the crash, the "sine wave" can be replaced here by the first term of its progression. Then approximately applies:

solving the time to obtain:

thus, ideal contact between the occupant protection device 115 and the occupant occurs at this time. If the deployment of the airbag requires a time Δt, the ideal activation time point 132 or ignition time point TTF can be determined as follows:

further, by using the result in the deceleration equation, an estimated value of the collision velocity of the occupant against the airbag can be calculated:

the method 200 may enable the determination of the ideal activation time point 132 for the actual collision, in particular on the basis of the above-described model-based equations.

Essentially, the aim is first to determine the product k=a·ω from the acceleration signal 103 as a crash-specific variable 125. For this purpose, the following calculation steps are preferably performed in real-time periods. Hereinafter, the variable t shall also represent the time stamp of the corresponding calculation cycle.

1. The acceleration signal is preferably initially filtered.

2. The signal obtained in this way is integrated numerically. A signal dv' (t) is obtained.

3. From this the variable k (t) is calculated with the following rule:

4. By substitution, a temporary estimated value TTF (t) of the ignition timing point can be obtained in each calculation period t:

in the case of an actual acceleration signal, the function TTF (t) will typically have different values over time, see also fig. 3. The actual ideal activation time 132 or ignition time TTF is now determined by the following equation (intersection point)

TTF(t)＝t

If appropriate, the ideal ignition point is precisely selected as the value for which the time actually elapsed from the start of the collision in one calculation cycle corresponds exactly to the currently calculated function value.

By means of this value, the expected impact speed to the airbag can also be determined by using the equation given and used for the modification of the control.

Other embodiments will be described below.

If an internal sensor system is present in the vehicle 100, the distance between the internal sensor and the head of the occupant may be determined therefrom. This can be done, for example, by subtracting another variable from the variable determined by the sensing system, so that the result represents a measure of the initial distance between the occupant and, for example, the deployed airbag. The distance does not necessarily have to correspond to the geometric distance between the head and the airbag, but may also be slightly smaller or slightly larger according to predefined technical requirements. The restraining effect of the airbag can thereby be further optimized. The distance need not be constant, but may also depend on other parameters, such as accident severity, impact speed, etc. If no internal sensor system is present, a standard value can be set, for example, which corresponds to the most frequent seat position or to the seat position with the lowest risk of injury to the occupant, which is statistically or individually caused in combination with the activation of the occupant protection device 115 and the severity of the accident.

The ideal activation time point 132 can be calculated for each seat position and occupant of the vehicle 100, respectively, by taking into account the respective positions of the vehicle and the occupant mass. Here, the mass of the occupant may optionally be assumed to be part of the actual mass of the occupant. If the mass of the occupant is unknown, a standard mass may be assumed according to one embodiment. Which may be determined, for example, based on accident severity, impact velocity, etc.

The value determined by means of the device 120 or according to the method 200 is only used further if, for example, the previous acceleration has exceeded a predetermined minimum threshold value.

According to one embodiment, the value of the collision-specific variable 125 or k=aω can also be generated directly from the information of the pre-collision sensor, such as the environmental sensor 104, or the environmental signal 105. The following relationship is used in this case:

wherein v is _rel For the relative speed between the host vehicle 100 and the obstacle, m, determined by the pre-crash sensor or the environmental sensor 104 ₁ Is the mass of the host vehicle 100 as known, and D is the combination of the vehicles in a collisionStiffness, which is derived from the expected type of collision and the characteristics of the vehicle, as it can be determined from pre-crash information. The expression may be rewritten as:

here, D ₁ And D ₂ Is the effective rigidity of the vehicle or the object of the other side. From this it will be determined that:

the variable can now be used directly as the activation time, but the ignition time TTF determined above in point 4 can also be fused with the variable by forming a weighted average from the variables. The weights are preferably based on the quality of the pre-crash information. If the quality is higher, its weight is also higher, and if the quality is lower, its weight is also lower.

According to another embodiment, the actual ignition timing point may be calculated even before the original ignition timing point is reached, see fig. 4. The following methods may be used herein: the time-dependent function TTF (t) is from here named t ₀ Is expanded at the current time point of (2):

intersection point is TTF (t) =ttf _new At (t) =t, can be set as

Solving for t and taking TTF _new (t) replaces t.

The first order expansion becomes

Alternatively, a second order expansion may be used

This provides two possible solutions:

a solution of physical significance is used herein.

If additional criteria are met, the ignition timing determined by these equations is used. The additional criteria may be: at TTF from the beginning of collision _new The difference from the current time is less than a certain preset value. At TTF from the beginning of collision _new The difference from the current time is less than a certain preset value multiplied by a coefficient.

According to another embodiment, the performance of the method 200 may be further improved by the following equation

The variable deltas is used in ^* Instead of deltas, namely:

where Δs ^* With deltas byThe relation is as follows:

wherein the degree of expansion k and the expansion coefficient a _n Can be freely selected according to requirements, or alternatively be predetermined as a function of deltas, i.e

This gives the following overall applicability

The advantage of this expression is that it is thereby possible to take into account the fact that the assumption of free-wheeling is only approximate. By means of the method, consistency with reality can be improved.

According to another embodiment, the performance of the system may be further improved by: the coefficient is also dependent on the belt condition, i.e. whether the occupant is belted or not, or on other further parameters, such as occupant mass or occupant height.

For repetition, note again that the following expression is obtained by setting k=aω:

according to one embodiment, for a variable or a particular value k by reference ^* The specific preset acceleration signal or the reference acceleration signal is characterized to obtain a reference activation time point or a specific trigger time TTF ^* ：

For k ^* Solving to obtain:

on the other hand, the acceleration of the first collision stage may be approximately determined by a linear expression:

a(t)＝k·t。

whereby the speed change dv is obtained by integration:

and the forward displacement ds for the occupant is obtained by integrating again:

if the previously calculated TTF is used for k here ^* K of (2) ^* Then obtain

Where ds can be identified using a constant threshold THD of forward displacement:

the reference activation time or ignition time TTF obtained in the usual case ^* The following is shown:

if the threshold expression is substituted here, it will result in:

i.e.

This expression essentially describes the characteristics of a conventional ds-based TTF determination method: if the acceleration signal has the same k value as the signal used to calibrate the threshold, i.e. k=k ^* The ignition timing TTF' thus obtained corresponds to the correct ignition timing TTF ^* . There is a bias for all other cases. The example graph 600 in fig. 6 shows, in particular, the deviation of TTF from the correct value for a conventional ds-based approach. The TTF may correspond to a value TTF'. For ttf=10 ms, the values obtained in fig. 6 are illustratively consistent with the correct values.

In order to achieve the correct TTF over the entire range of k, the TTF' is now corrected by means of the method 200 as follows:

Assume that:

TTF _real -TTF ^* ＝R·(TTF′-TTF ^* )

wherein TTF _real The correct ignition time should be indicated. Then for R:

i.e.

Here, R may represent the set model rule 128 and is referred to as a correction factor.

The correct ignition time is thus:

TTF _real ＝R·(TTF′-TTF ^* )+TTF ^* 。

thus, in a specific application caseThe following procedure will be obtained: for having the value k ^* Setting the threshold THD to ds such that the point in time is exceeded or the point in time is exceeded generates the correct time to trigger TTF ^* . For example, the collision having the shortest possible trigger time is selected as the reference collision. In an actual collision deviating from the reference collision, a collision-specific variable k is determined from the collision signal or acceleration signal 103 and a corresponding correction factor R is calculated. If ds exceeds the threshold THD during a collision, the time is stored as TTF' and by means of TTF _real ＝R·(TTF′-TTF ^* )+TTF ^* The correct activation time point is calculated. As long as the elapsed time from the start of collision reaches TTF _real The occupant protection device 115 is activated.

According to one embodiment, the determination of the correction factor R may be simplified by approximating the value of R as a constant. This is a reasonable approximation given that the type of collision or accident is constant. In fig. 7 a constant value is set for R.

According to a further embodiment, different R values can be stored for different accident types, wherein, for example, for the accident types "full coverage", "partial coverage" or "front accident with small angle deviation" the respective R value can be stored and used for the calculation if, for example, the respective accident situation is detected by means of a pre-crash sensor, a front sensor or the like. Referring to fig. 9, as another correction factor R is selected for the type of collision represented by the additional line 904, the filled-in value will also be converted into the correct characteristic in this regard.

Note again that, and repeating briefly, the following expression is obtained by setting k=aω:

here, the seat position is represented by a distance dimension Δs, which is a standard seat position with respect to the occupant protection device 115 (e.g., an airbag).

According to one embodiment, for a seat position with an offset s' relative to this position Δs, the following expression is derived:

from TTF _std The collision-specific variable k can be calculated in the equation:

substituting into the equation for TTF' yields:

thereby having the following characteristics

Using this equation, the activation time point TTF, which can be determined for the standard position (denoted by Δs), is determined _std Converted into an ideal activation time TTF 'adapted to the seat position offset by the value s'.

According to one embodiment, the standard position for which the standard ignition time calculation is performed is selected such that it corresponds to the foremost seat position. This has the advantage that all other seat positions are rearward, so that all corrected or ideal ignition points are correspondingly later. Thus, optimal control performance can be achieved by simply delaying ignition to this point in time. This may also be performed for each individual seat in the vehicle 100 with little computational effort.

An embodiment may be read as having both a first feature and a second feature, if it includes an "and/or" conjunctive word between the first feature and the second feature, and having only the first feature, or only the second feature, according to another embodiment.

Claims

1. A method (200) for controlling an occupant protection device (115) of a vehicle (100) in the event of a collision of the vehicle (100), wherein the method (200) comprises the steps of:

-reading (210) an acceleration signal (103) from an interface (121) for an acceleration sensor (102) of the vehicle (100), and/or-reading an ambient signal (105) from an interface (121) for an ambient sensor (104) of the vehicle (100);

-determining (220) a variable (125) specific to the collision by using the acceleration signal (103) and/or the environment signal (105) according to a determination rule (123);

substituting (230) the determined collision-specific variable (125) for at least one parameter of a predefined model rule (127) in order to generate a set model rule (128), wherein the predefined model rule (127) for modeling a collision has a sinusoidal signal profile that varies over time;

determining (240) an ideal activation time point (132) for activating the occupant protection device (115) by using the set model rules (128);

-generating (250) a control signal (135) for controlling the occupant protection device (115) by using the desired activation time point (132), wherein the control signal (135) comprises an activation command for activating the occupant protection device (115); and is also provided with

-providing (260) the control signal (135) for output to an interface (139) for the occupant protection device (115).

2. The method (200) of claim 1, wherein in the substituting (230) step the variable is substituted for a parameter representing the product of a presumed amplitude and a presumed angular frequency, wherein the predefined model rule (127) defines a presumed activation time point as a difference between a cubic root of a quotient of a predetermined distance measure and the parameter and a predetermined activation duration of the occupant protection device (115).

3. The method (200) according to claim 1 or 2, wherein in the step of determining (220), the variable (125) is determined as a product of twice the acceleration signal (103) integrated numerically and a quotient of the square in time according to a first determination rule, and/or the variable (125) is determined as a product of a relative speed between the vehicle (100) and a collision object, identified by the ambient signal (105), and a quotient of a combined stiffness of the vehicle (100) and the collision object and a mass of the vehicle (100) according to a second determination rule.

4. A method (200) according to claim 3, wherein in the substituting (230) step the variable (125) solved according to the first solving rule and the variable (125) solved according to the second solving rule are substituted into the predefined model rule (127) for the parameter independently of each other to generate a set first model rule and a set second model rule, wherein in the determining (240) step a first activation time point is generated by using the set first model rule and a second activation time point is generated by using the set second model rule, and the ideal activation time point (132) is determined as a weighted average of the first activation time point and the second activation time point, wherein the weighting factor depends on the quality of the ambient signal (105).

5. The method (200) according to claim 1 or 2, wherein in the determining (240) step a temporary activation time point is generated in each time step by using the set model rules (128), wherein a temporary activation time point generated in a time step is determined to be an ideal activation time point (132) if a time period that has elapsed since the start of a collision corresponds in that time step to the temporary activation time point in the time step.

6. The method (200) according to claim 1 or 2, wherein in the generating (250) step the control signal (135) is generated by using an impact speed of an occupant of the vehicle (100) to the occupant protection device (115) estimated by means of an estimation rule defining the impact speed as an acceleration signal (103) which is integrated singly at the substituted ideal activation time point (132).

7. The method (200) according to claim 1 or 2, wherein in the determining (240) step the ideal activation time point (132) is determined by a series expansion using the set model rules (128).

8. The method (200) according to claim 1 or 2, having the following defining (205) steps: the threshold value of the doubly integrated predefined reference acceleration signal is specified by using a reference rule for a reference collision with a reference variable specific to the reference collision and a reference activation time point specific to the reference collision,

Wherein in the step of determining (220), an exceeding point in time when the doubly integrated acceleration signal (103) exceeds the threshold value is determined by using the acceleration signal (103),

wherein in the determining (240) step the ideal activation time point (132) is determined by using the set model rule (128) as a correction factor for a determination rule, wherein the determination rule is defined as the sum of the first addend and the reference activation time point as the second addend multiplied by the set model rule (128) and the difference between the overrun time point and the reference activation time point.

9. The method (200) of claim 8, wherein in the determining (240) step, the set model rules (128) represent a correction factor that is predefined in accordance with the identified collision type.

10. The method (200) according to claim 1 or 2, wherein in the determining (240) step the seat position of the occupant of the vehicle (100) displaced relative to a standard seat position is taken into account in the set model rules (128), wherein the standard seat position represents a seat position as far forward as possible in the direction of travel of the vehicle (100), wherein the displaced seat position represents a seat position identified by using an internal sensor signal of an internal sensor of the vehicle.

11. The method (200) of claim 7, wherein the expansion coefficient of the series expansion takes into account a seat belt buckle status and/or a body characteristic of an occupant of the vehicle (100).

12. An apparatus (120) for a vehicle configured to perform and/or control the steps of the method (200) according to any one of claims 1 to 11 in respective units (122, 124, 126, 130, 134, 136).

13. An occupant protection system (110) for a vehicle (100), wherein the occupant protection system (110) has the following features:

an occupant protection device (115); and

the device (120) of claim 12, wherein the device (120) and the occupant protection device (115) are signally connected to each other.

14. A machine readable storage medium having stored thereon a computer program configured to perform and/or control the steps of the method (200) according to any of claims 1 to 11.