EP1928706A1

EP1928706A1 - Method and device for triggering person protecting means during a rolling process

Info

Publication number: EP1928706A1
Application number: EP06764300A
Authority: EP
Inventors: Marc-Andre Golombeck; Andreas Schaefers
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 2005-09-20
Filing date: 2006-08-02
Publication date: 2008-06-11
Also published as: DE102005044763B4; US8433480B2; JP2009508739A; US20100211245A1; DE102005044763A1; WO2007033853A1

Abstract

Disclosed are a device and a method for triggering person protecting means, which are characterized in that a rolling rate sensory mechanism (DR) generates a rolling rate while an acceleration sensory mechanism detects the transversal acceleration (ay) and the vertical acceleration (az). An integrator (10) is provided which integrates the rolling rate into an angle. Said integrator begins integrating the rolling rate when the rolling rate exceeds a first threshold value while ending the integration process when the rolling rate falls below a second threshold value. In addition, a threshold value controller (SW) is provided which adjusts the first and/or the second threshold value in accordance with the transversal and/or the vertical acceleration. A processor triggers person protecting means in accordance with the angle and other criteria.

Description

description

title

Method and device for triggering personal protection devices in a rollover process

State of the art

The invention relates to a device or a method for triggering personal protection means in a rollover process according to the preamble of the independent patent claims.

From EP 1 258 399 B1, it is already known, when activating an occupant protection application in a motor vehicle, to take into account at least the rotational speed, that is to say the roll rate, as well as accelerations in the vehicle vertical and transverse vehicle directions during a rollover process. In a further development, it is provided that the determination of the angle of rotation can also be made.

Advantages of the invention

The inventive device for triggering personal protection means in a

Rollover operation or the corresponding method with the features of the independent claims have the advantage that the integration of the roll rate is started and stopped by adaptive thresholds. This makes it possible to begin situationally early with the integration of the roll rate, so that triggering of the personal protection agent is also possible earlier, since the roll angle as a triggering criterion increases faster and thus leads to a triggering in a threshold value comparison. To determine these thresholds, which determine the starting and stopping of the integration, the vehicle lateral and vertical acceleration is used. These two acceleration components are helpful in the plausibility of the roll rate, as these two accelerations span the plane in which the roll is performed. By lowering the thresholds that determine the integration in driving maneuvers with high vertical and lateral accelerations, an early start of the roll angle integration is achieved and thus gained a valuable time to generate the earliest possible and safe triggering decision. The value by which the thresholds are lowered is dependent on the respective application and thus adjustable. In particular, it can be determined whether the first threshold value is changed and / or the second threshold value. In particular, by lowering the second threshold, ie the threshold which causes the termination of the integration by falling below it, one obtains a good accuracy with respect to the actual roll angle even at times of low roll rates. The change or reduction of the first and second

Threshold can remain active as long as the conditions for lowering the thresholds are met. Optionally, it is possible to work with time constants, d. H. the change of the thresholds is made for a given or adaptively determined time. The method according to the invention or the device according to the invention bring about increased stability and early triggering reliability of the triggering algorithm. The inventive method and the device according to the invention can be easily integrated into existing systems.

Advantageous improvements of the device or method mentioned in the independent claims are possible by the measures and developments listed in the dependent claims.

It is particularly advantageous that a roll angle can be determined from the transverse and the vertical acceleration itself, and that is then subjected to a threshold value analysis via a known equation and this roll angle in order to determine the first and second threshold values for the integration as a function of this comparison adjust.

In addition, it is advantageous that for determining the change of the first and second threshold value, the transverse and the vertical acceleration themselves are each subjected to a threshold value comparison, wherein a combination of the transverse and vertical acceleration can also be subjected to a single threshold value. The transgression time of the transverse or vertical acceleration of such threshold values can also be taken into account in determining the change of the first and second threshold values for the roll rate. drawing

Embodiments of the invention are illustrated in the drawings and are explained in more detail in the following description.

Show it:

1 shows a block diagram of the device according to the invention, FIG. 2 shows a roll rate time diagram,

FIG. 3 shows a lateral acceleration time diagram;

FIG. 4 shows a vertical acceleration time diagram and

Figure 5 is a flowchart.

description

Statistics from the US show the importance of passive safety in vehicle rollovers: in 1998, half of all fatal road accidents were caused by vehicle rollover. After all, vehicle rollover accounts for around 20% of all accidents.

To trigger personal protection devices in a vehicle rollover, the roll angle can be used as a decision criterion. The roll angle can be determined by integrating the yaw rate around the vehicle's longitudinal axis. Due to sensor noise, the necessary rate of rotation is selected to be high in order not to activate the angle integrator too often. The problem here is that generally the angle integrator runs behind the actual roll angle and thus triggering decisions can only be made later. In addition, it may be in slow rollover events with low rotation rate that the rollover is detected very late or not at all.

According to the invention, it is therefore proposed to provide the angle integrator with adaptive threshold values in order to optimize the integration. For determining these threshold values, it is advantageous to use the vertical and transversal or vehicle lateral acceleration, which already occurs before the occurrence of a significant rolling acceleration. - A -

rate is relatively high. In order to bring a vehicle to overturn, first forces must act, which in turn generate a rate of turn. These forces can be measured with the acceleration sensors and thus used as an early indicator of a possibly unstable vehicle condition, as they hurry ahead of the roll rate.

FIG. 1 illustrates in a block diagram the device according to the invention. A roll rate sensor DR is connected to an integrator 10 so that the roll rate can be integrated to a roll angle. In the present case, this integration is part of a microcontroller μC and is implemented in software. It is possible to arrange the integration outside the microcontroller μC in the control unit for controlling the personal protection means. The roll rate sensor DR is a micromechanically formed sensor which is optimized for detecting the rotation rate. The integration in the integrator 10 begins when the roll rate has exceeded a first threshold. It ends when it falls below a second threshold. Therefore, the second threshold is lower or identical to the first threshold. These two threshold values for starting and stopping the integration are determined adaptively according to the invention. For their determination, the signals of an acceleration sensor in the vehicle in the vertical direction az and in the vehicle transverse direction, ie in the transverse direction ay used. Also for detecting this acceleration are micromechanical sensors or sensor systems. These acceleration values go to a threshold control SW after filtering, amplification and digitization. The threshold control SW determines from the vehicle vertical and vehicle transverse acceleration the first and second thresholds that determine the starting and stopping of the integration of the roll rate. This is done by the threshold value control SW with threshold value comparisons, the vehicle lateral and vehicle vertical acceleration. Ie. if the vehicle lateral and / or the vehicle vertical acceleration exceed predetermined threshold values, then this leads to a lowering of the first or second threshold value for the roll rate. Here, alternatively, it can also be provided that the vehicle lateral acceleration and the vehicle vertical acceleration are not taken, but the integrated vehicle lateral acceleration and vehicle vertical acceleration. Also averaging or the like are possible here. Moreover, it is possible that if only the vehicle lateral acceleration or the vehicle vertical acceleration is below a threshold value and the other acceleration does not exceed the threshold value, then the roll rate threshold values are not changed. However, it is also possible that if only one of these thresholds is exceeded, the thresholds for the roll rate will be lowered. In an alternative embodiment, it is possible for the roll angle to be determined from the vehicle lateral acceleration and the vehicle vertical acceleration using the following equation:

Where ay is the vehicle lateral acceleration, az is the vehicle vertical acceleration, v ² g is the gravitational acceleration, - the centripetal acceleration. The centripetal acceleration can be determined as the only variable. Namely from the following equation:

This roll angle, which is determined from the first equation, can also be compared to a predetermined threshold value in order to determine the first and second threshold values for the roll rate. As soon as this threshold is exceeded, one would assume a corresponding roll angle of the vehicle and actively lower the thresholds for the roll rate, should the integrator not yet have been started.

The integrator 10 now supplies to the algorithm Al the roll angle which was determined by the integration of the roll rate. The algorithm Al determines from the roll angle and other parameters, for example the current roll rate and / or acceleration values and / or the occupant recognition and classification, which was determined by an interior sensor IOS, whether restraining means should be triggered in the vehicle or not. Depending on this, then the personal protection RHS, such as airbags or belt tensioners or roll bars are controlled. The algorithm Al, the integrator 10 and the threshold value control SW are implemented here as software functions on a microcontroller .mu.C in a control device for controlling the personal protection means RHS. The other components may be inside or outside the controller.

FIG. 2 illustrates, in a roll rate time diagram, the function that the integrator 10 performs. The time is plotted on the abscissa and the roll rate ωx on the ordinate. The curve 20 shows the course of the roll rate ωx. At the time Tl exceeds the Roll rate 20 the first threshold Sl. At this time, therefore, the integration of the roll rate is started. At time T2, the roll rate 20 drops below the second threshold S2. Ie. at time T2 the integration is stopped. The result is the roll angle given to the algorithm. According to the invention, the threshold values S1 and S2, indicated by the arrows, are changed as a function of the vehicle lateral acceleration and the vehicle vertical acceleration.

FIG. 3 explains in a vehicle lateral acceleration time diagram on the basis of which event the threshold values S1 and S2 are changed. The vehicle lateral acceleration ay is plotted on the ordinate and the abscissa on the time t. The curve 30 shows the course of the vehicle lateral acceleration as a function of time. At time T3, the vehicle lateral acceleration ay exceeds the threshold value S3. The threshold S3 is taken here to check whether the thresholds Sl and S2 must be changed due to a signal ay. This is achieved at time T3. This means that the vehicle lateral acceleration is so great that a lowering of the thresholds Sl and S2 is necessary.

FIG. 4 shows a corresponding time diagram for the vehicle vertical acceleration as a function of time. Again, the time t is shown on the abscissa and the vehicle vertical acceleration az is shown on the ordinate. Curve 40 shows the vehicle vertical acceleration as a function of time. At time T4, the curve 40 exceeds the threshold value S4. That is, in the threshold control, it has now been found that the curve 40, that is, the vehicle vertical acceleration, is greater than the threshold value S4. Thus, the thresholds Sl and S2 can be reduced accordingly.

FIG. 5 shows a flow chart of the method according to the invention. In method step 500, the roll rate is determined by means of the rotation rate sensor DR. In method step 501, the vehicle acceleration and the vehicle vertical acceleration are determined by means of the acceleration sensors az and ay. In step 502, the roll rate is integrated. The integration of the roll rate is determined after exceeding the roll rate of the threshold values Sl and S2. These are changed depending on the vehicle lateral acceleration and the vehicle vertical acceleration. The resulting roll angle is checked in method step 503 with a triggering criterion, ie a threshold value, the roll angle is large enough and others triggers trigger conditions, then it comes to triggering in step 504 and thus to control the personal protection. If the roll angle is not large enough, then no triggering occurs and in method step 505 the method ends.

Claims

claims

1. A device for triggering personal protection devices (RHS) in a rollover process with a roll rate sensor (DR), which determines a roll rate (ωx) - an acceleration sensor, a transversal and a vertical acceleration (az, ay) detects an integrator (10), which integrates the roll rate (ωx) into an angle, wherein the integrator (10) is configured such that an integration of the roll rate (ωx) starts when the first threshold value (Sl) is exceeded by the roll rate (ωx) and falls below a second one Threshold (S2) by the roll rate ends a threshold control (SW), which adjusts the first and / or second threshold depending on the transverse and / or vertical acceleration (ay, az) a processor (.mu.C), which in dependence Angle that activates personal protective equipment (RHS).

2. Device according to claim 1, characterized in that the processor (.mu.C) is configured such that the processor (.mu.C) determines a roll angle from the transverse and the vertical acceleration (ay, az) and the threshold value control (SW) determines the first and the second threshold value (Sl, S2) in dependence on the

Roll angle adjusts.

3. Device according to claim 1, characterized in that the threshold value control (SW) subjects the transverse and the vertical acceleration (ay, ax) to a threshold value comparison and the first and the second threshold value (S 1, S2) as a function of this comparison certainly.

4. The device according to claim 3, characterized in that the threshold value control (SW) additionally takes into account an excess time of the transversal and the vertical acceleration in the threshold value comparison.

5. Method for triggering personal protection devices in a rollover process with the following method steps:

- Determination of a roll rate (501)

Detecting transversal and vertical acceleration (502) integrating the roll rate (ωx) into an angle, the integration starting when the roll rate (ωx) exceeds a first threshold (Sl) and ending when the roll rate (ωx) is a second threshold (S2) falls below (502) - adjustment of the first or second threshold value (Sl, S2) as a function of

Transversal and vertical acceleration Activation of the personal protective equipment as a function of the angle.

6. The method according to claim 5, characterized in that from the transverse and the vertical acceleration (ay, az) a roll angle is determined and the first and the second threshold value (Sl, S2) are set in dependence on the roll angle.

7. The method according to claim 5, characterized in that the transverse and the vertical acceleration (ay, az) is subjected to a threshold value comparison and the first and the second threshold value (Sl, S2) are determined in dependence on this comparison.

8. The method according to claim 7, characterized in that in addition an overrun time of the transverse and the vertical acceleration (ay, az) at

Threshold comparison is taken into account.