Method and device for controlling occupant protection means in a vehicle

• US 20060167603A1
• Filed: 02/06/2004
• Published: 07/27/2006
• Est. Priority Date: 02/07/2003
• Status: Abandoned Application

• Current Assignee: Siemens AG
• Original Assignee: Siemens AG
• Inventors: Watanabe, Akinori, Brandl, Jurgen, Lo, Serigne, Kloss, Dieter, Grasshoff, Helge
• Application Number:
  US10/544,960
• Publication Number:
  US 20060167603A1
• Time in Patent Office: Days
• US Class Current: 701/45
• CPC Class Codes: B60R 2021/01322 comprising variable thresholds, e.g. depending from other collision parameters
• CPC Class Codes: B60R 21/013 including means for detecting collisions, impending collisions or roll-over
• CPC Class Codes: B60R 21/0132 responsive to vehicle motion parameters , e.g. to vehicle longitudinal or transversal deceleration or speed value
• CPC Class Codes: B60R 21/01336 using filtering
• CPC Class Codes: B60R 21/0136 responsive to actual contact with an obstacle , e.g. to vehicle deformation, bumper displacement or bumper velocity relative to the vehicle monitoring crash strength in combination with passenger seat detection B60R21/01558

Abstract

The invention relates to a method and a device for controlling occupant protection means in a vehicle. According to said method, a first crash variable (AAA), derived from the absolute value for the crash signal of a crash sensor, preferably from the acceleration signal of an acceleration sensor, is compared with a first firing threshold (th1a, th1b, th1c). In addition, a second crash variable (wj, wv, ws), derived in a different manner from the crash signal (a) of the crash sensor (1) is compared with a second firing threshold (th2a, th2b, th2c). The occupant protection means is only fired if the first crash variable (AAA) exceeds the first firing threshold value (th1a, th1b, th1c) and simultaneously the second crash variable (wj, wv, ws) exceeds the second firing threshold (th2a, th2b, th2c).

Claims

1-11. -11. (canceled)

12. A method for controlling an occupant protection device in a motor vehicle, which comprises the steps of:

delivering, via a crash sensor, a crash signal;

deriving a first crash variable being an absolute value of the crash signal;

comparing the first crash variable with a first firing threshold;

comparing a second crash variable derived from the crash signal with a second firing threshold; and

controlling the occupant protection device in dependence on whether the first and second firing thresholds are exceeded.

13. The method according to claim 12, which further comprises deriving the first crash variable as an integral of the absolute value of the crash signal over a restricted period of time.

14. The method according to claim 12, which further comprises making the first crash variable available as a low-pass-filtered digital value.

15. The method according to claim 12, which further comprises forming the second crash variable from a sum of a number of difference terms of two chronologically consecutive digital values of the first crash variable in each case in accordance with:

$\begin{array}{cc}\mathrm{wj}<br><br>\left(t_n,b\right)=\underset{i=n-b}{\overset{n}{\sum <br><br>}}<br><br>\left({\mathrm{AAA}}_i<br><br>\left(t_i,b\right)-{\mathrm{AAA}}_{i-1}<br><br>\left(t_{i-1},b\right)\right).& \left(2\right)\end{array}$

where wj is the second crash variable.

16. The method according to claim 12, which further comprises deriving the second crash variable from an integral of the crash signal over a restricted period of time.

17. The method according to claim 12, which further comprises deriving the second crash variable from an integral of a third crash variable over a restricted period of time.

18. The method according to claim 12, which further comprises:

providing an acceleration sensor as the crash sensor; and

providing the crash signal as an acceleration signal.

19. The method according to claim 13, which further comprises:

deriving the first crash variable from a sum of chronologically consecutive digital values of the absolute value of the crash signal in accordance with;

$\begin{array}{cc}\mathrm{AAA}<br><br>\left(t_n,b\right)=\frac{1}{b}<br><br>\underset{i=n-b}{\overset{n}{\sum <br><br>}}<br><br><br><br>a_i<br><br>\left(t_i\right)<br><br>·<br><br>1<br><br>\text{\hspace{1em}<br><br>}<br><br>\mathrm{ms},& \left(1\right)\end{array}$

where AAA is the first crash variable, t_n is a time of determination of the first crash variable, b+1 is a number of sum terms, i is a sum index for a summation of i=n−

b to n, a_i are the chronologically consecutive digital values of the crash signal, and ms stands for a physical unit milliseconds.

20. The method according to claim 16, which further comprises deriving the second crash variable from a sum of chronologically consecutive digital values of the crash signal in accordance with:

$\begin{array}{cc}\mathrm{wv}<br><br>\left(t_n,b\right)=\underset{i=n-b}{\overset{n}{\sum <br><br>}}<br><br>a_i<br><br>\left(t_i\right)·<br><br>1<br><br>\text{\hspace{1em}<br><br>}<br><br>\mathrm{ms}& \left(3\right)\end{array}$

where wv is the second crash variable and a_i is the digital values of the crash signal.

21. The method according to claim 17, which further comprises deriving the second crash variable from a sum of chronologically consecutive digital values of the third crash variable in accordance with

$\begin{array}{c}\mathrm{ws}\end{array}$

( t n , b ) = ∑

i = n - b n ⁢

Δ

⁢

 

⁢

v i ⁡

( t i ) ·

1 ⁢

ms = ∑

i = n - b n ⁢

∑

i = 0 n ⁢

a i ⁡

( t i ) ·

1 ⁢

 

⁢

ms ·

1 ⁢

 

⁢

ms , ( 4 )

where ws is the second crash variable, and Δ

v is the third crash variable resulting from a time integral of the crash signal being a sum of the consecutive digital values a_i of the crash signal in accordance with;

$\begin{array}{cc}\mathrm{\Delta <br><br>}<br><br>\text{\hspace{1em}<br><br>}<br><br>v<br><br>\left(t_n\right)=\underset{i=0}{\overset{n}{\sum <br><br>}}<br><br>a_i<br><br>\left(t_i\right)·<br><br>1<br><br>\text{\hspace{1em}<br><br>}<br><br>\mathrm{ms}.& \left(5\right)\end{array}$

22. A device for controlling an occupant protection device in a motor vehicle, the device comprising:

an acceleration sensor for capturing accelerations during a motor vehicle crash and generating an acceleration signal;

acceleration signal processing units coupled to said acceleration sensor for converting the acceleration signal generated by the acceleration sensor into a number of crash variables, said acceleration signal processing units each having a signal output;

an activation unit;

an evaluation unit having first and second signal inputs each respectfully connected to said signal output of each of said acceleration signal processing units, said evaluation unit evaluating the crash variables fed to it, said evaluation unit outputting a firing signal to said activation unit if at least two of the crash variables exceed a firing threshold in each case;

said acceleration signal processing units containing;

a first acceleration signal processing unit having a signal output and an absolute value generator with a first input receiving the acceleration signal and a first signal output outputting an absolute value of the acceleration signal to the signal output of said first acceleration signal processing unit, the absolute value of the acceleration signal being a first crash variable; and

a second acceleration signal processing unit having an input receiving the acceleration signal from said acceleration sensor and a signal output outputting a second crash variable derived from the acceleration signal, the second crash variable being fed to said second input of said evaluation unit.

23. The device according to claim 22, wherein said first acceleration signal processing unit has an integration unit connected downstream of said absolute value generator, said integration unit connected between said first signal output of said absolute value generator and said signal output of said first acceleration signal processing unit, at said signal output of said first acceleration signal processing unit the first crash variable is present as a time integral of the absolute value of the acceleration signal, in accordance with

$\begin{array}{c}\mathrm{AAA}\end{array}$

( t n , b ) = 1 b ⁢

∑

i = n - b n ⁢



a i ⁡

( t i ) 

·

1 ⁢

 

⁢

ms , ( 1 )

whereby AAA is the first crash variable, a is the acceleration signal, t_n is a time of determination of the first crash variable AAA, b+1 a number of sum terms, i is a sum index for summation of i=n−

b to n, and ms stands for the physical unit milliseconds.

24. The device according to claim 22, wherein said second acceleration signal processing unit includes:

a delay element having a signal input receiving the first crash variable and a signal output; and

a logical addition/subtraction unit having a first signal input connected to said signal output of said delay element, a second signal input receiving the first crash variable, a third signal input, and a signal output connected both to said signal output of said second acceleration signal processing unit and also to said third signal input of said addition/subtraction unit, said signal output of said second acceleration signal processing unit outputting the second crash variable, said second accelerating processing unit forming the second crash variable as a sum of a number of difference terms of two chronologically consecutive digital values of the first crash variable in each case in accordance with

$\begin{array}{cc}\mathrm{wj}<br><br>\left(t_n,b\right)=\underset{i=n-b}{\overset{n}{\sum <br><br>}}<br><br>\left({\mathrm{AAA}}_i<br><br>\left(t_i,b\right)-{\mathrm{AAA}}_{i-1}<br><br>\left(t_{i-1},b\right)\right)& \left(2\right)\end{array}$

where wj is the second crash variable.

25. The device according to claim 22, wherein said second acceleration signal processing unit includes a second integration unit for performing a time integration of any input signal received, said second integration unit having an input receiving the acceleration signal and an output connected to said signal output of said second acceleration signal processing unit, said second acceleration signal processing unit outputting the second crash variable embodied as a speed signal in accordance with:

$\begin{array}{cc}\mathrm{wv}<br><br>\left(t_n,b\right)=\underset{i=n-b}{\overset{n}{\sum <br><br>}}<br><br>a_i<br><br>\left(t_i\right)·<br><br>1<br><br>\text{\hspace{1em}<br><br>}<br><br>\mathrm{ms}& \left(3\right)\end{array}$

where wv is the second crash variable.

26. The device according to claim 22, wherein said second acceleration signal processing unit includes a second integration unit for performing a double time integration of input signals received, said second integration unit having an input receiving the acceleration signal and outputting the second crash variable embodied as a preliminary displacement signal in accordance with:

$\begin{array}{cc}\mathrm{ws}<br><br>\left(t_n,b\right)=\underset{i=n-b}{\overset{n}{\sum <br><br>}}<br><br>\mathrm{\Delta <br><br>}<br><br>\text{\hspace{1em}<br><br>}<br><br>v_i<br><br>\left(t_i\right)·<br><br>1<br><br>\text{\hspace{1em}<br><br>}<br><br>\mathrm{ms}=\underset{i=n-b}{\overset{n}{\sum <br><br>}}<br><br>\underset{i=0}{\overset{n}{\sum <br><br>}}<br><br>a_i<br><br>\left(t_i\right)·<br><br>1<br><br>\text{\hspace{1em}<br><br>}<br><br>\mathrm{ms}·<br><br>1<br><br>\text{\hspace{1em}<br><br>}<br><br>\mathrm{ms}<br><br><br><br>\mathrm{with}& \left(4\right)\\ \mathrm{\Delta <br><br>}<br><br>\text{\hspace{1em}<br><br>}<br><br>v<br><br>\left(t_n\right)=\underset{i=0}{\overset{n}{\sum <br><br>}}<br><br>a_i<br><br>\left(t_i\right)·<br><br>1<br><br>\text{\hspace{1em}<br><br>}<br><br>\mathrm{ms},& \left(5\right)\end{array}$

so that in accordance with the double time integration of the acceleration signal by said second integration unit the second crash variable is used as a measure of a preliminary displacement experienced by a vehicle occupant relative to the motor vehicle.