JPH05286407A - Collision judging device - Google Patents

Abstract

PURPOSE:To enable collision judgement by the use of few acceleration sensors and carry out accurate collision judgement by providing a means for judging a collision mode based on a pattern feature of an acceleration signal to select an appropriate threshold value in compliance with the collision mode. CONSTITUTION:A G signal from an acceleration sensor (G sensor) 1 whose high frequency component is eliminated at an LPF 2 is integrated in an integration part 3. A collision mode judging part 5 judges a collision mode based on a correlation value of a differential value of the G signal relative to a reference pattern, a level variation ratio of the G signal, a frequency component of the G signal, and the like. In threshold values 4, threshold values 1, 2,... suitable for the collision mode are prepared in advance, and a threshold value selecting part 6 selects a threshold value, based on a judgement result from the collision mode judging part 5, selects a threshold value suitable for the collision mode among the threshold values 1, 2.... In a comparison part 7, output DELTAV from the integration part 3 is compared with the selected threshold value, and when the former exceeds the latter a trigger signal is outputted to start a squib starting device 8.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a collision determination device,
In particular, the present invention relates to a collision determination device configured to analyze a G signal output from an acceleration sensor (hereinafter abbreviated as G sensor) to determine a collision mode.

[0002]

2. Description of the Related Art A conventional collision determination device integrates a G signal output from a G sensor for a certain period of time, and when the integrated value ΔV indicating the deceleration of a vehicle exceeds a predetermined reference value, a collision occurs. The determination is made and the airbag drive device is activated.

However, the differential value ΔV indicating the deceleration of the vehicle differs depending on the position of the vehicle on which the G sensor is installed. For this reason, conventionally, a plurality of G sensors are installed in each part of the vehicle, and the integrated value ΔV of each part of the vehicle is measured to determine the collision.

[0004]

As described above, in the conventional collision determination device, a plurality of G sensors are installed in each part of the vehicle,
Since the collision is determined by measuring the integrated value ΔV of each part of the vehicle, there is a problem that the collision determination algorithm is complicated and the system is expensive.

An object of the present invention is to eliminate the above-mentioned problems of the conventional device and to provide a collision determination device having a simple and inexpensive structure using less G sensors.

[0006]

In order to achieve the above object, the present invention provides a means for holding a plurality of threshold values adapted to a plurality of collision modes, and a collision mode from the characteristics of the pattern of the acceleration signal. And a threshold value selection unit for selecting a threshold value suitable for the collision mode from the plurality of threshold values according to the collision mode detected by the collision mode determination unit. The point is that it was done.

[0007]

According to the present invention, the collision mode is determined from the characteristics of the pattern of the acceleration signal, and an appropriate threshold value that matches the collision mode is selected. Therefore, it is possible to determine the collision using a small number of G sensors. It is possible to make an accurate collision determination.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to the drawings. FIG. 1 is a block diagram showing the function of one embodiment of the present invention.

In the figure, 1 is a G sensor mounted on a vehicle, 2 is an LPF (low-pass filter) which receives the G signal detected by the G sensor 1, and 3 is an integrator for integrating the G signal. Further, 4 is a collision of various modes, for example, a high-speed frontal collision, a medium-speed frontal collision, a high-speed oblique collision, a mode of diving into the lower part of the vehicle in front, a mode of rubbing the bottom of the vehicle body, etc. Thresholds corresponding to 1, 2, ...
Is.

Reference numeral 5 is a collision mode determination unit that determines the collision of the various modes based on the characteristics of the G signal pattern or its characteristic points, 6 is the threshold value selection unit, 7 is a comparison unit,
Reference numeral 8 is a squib activation device for inflating the airbag.

The collision mode determination unit 5 determines the correlation value of the differential value (dG / dt) of the G signal with respect to the reference pattern, the similarity value of the area of the G waveform with respect to the reference pattern, the level variation rate of the G signal, or the G signal. The collision mode is determined from the frequency component or the like or a combination thereof.

2 and 3 show examples of G waveforms obtained in various collisions. FIG. 2 (a) shows a high-speed frontal collision.
(b) shows the waveforms of a medium-speed frontal collision and the high-speed frontal collision of (c). Further, FIG. 3 (a) shows a waveform of a mode that dives into the lower part of the vehicle ahead, and FIG. 3 (b) shows a waveform of a mode that rubs the bottom of the vehicle body. As is apparent from the figure, the G waveform has a characteristic pattern for each collision mode.

Next, a method of determining the collision mode by obtaining the correlation value of the differential value (dG / dt) of the G signal with respect to the reference pattern will be described with reference to FIGS.

FIG. 4 is a reference pattern of a G signal at the time of collision stored in a reference pattern holding unit (not shown), and the waveform of FIG. 5 is a G waveform obtained by an actual collision. And

First, in the G waveform of FIG. 5, the variation amounts k1, k2, k3, ... Are sequentially obtained at each predetermined time interval A. Next, the reference change amounts K1, K2, K3, ... For each time interval A included in the reference pattern of FIG. 4 are sequentially output from a reference pattern holding unit (not shown), and the relative value Xn for each time interval A is set. Is calculated by the following formula.

Xn = kn / Kn Then, the relative value Xn is applied to the graph of the correlation function as shown in FIG. 6 to obtain the correlation value Rn.

Then, the correlation value Rn is integrated, and when the integrated value becomes a predetermined value or more, it is determined that the collision mode is the same as the reference pattern. On the other hand, when it is less than the predetermined value, it is determined that the collision mode is different from the collision mode of the reference pattern.

Further, similarly to the above, the collision mode can be determined from the level fluctuation rate of the G signal.

Further, the collision mode can be obtained from the similar value of the area of the G waveform to the reference pattern. This method is applied to a patent application by the applicant (Japanese Patent Application No. 4-7219).
No. 2), the explanation is omitted. Also,
The collision mode can be obtained from the frequency component of the G signal. Since this method is described in detail in the patent application by the present applicant (Japanese Patent Application No. 4-56641),
The description is omitted.

Next, the operation of this embodiment will be described with reference to FIG. The G signal output from the G sensor 1 mounted on the vehicle has a high frequency component removed by the LPF 2 and integrated by the integrator 3. At the same time, the collision mode determination unit 5 analyzes the G waveform and determines the collision mode by the method described above.

Since the threshold values 4 are prepared in advance as the threshold values 1, 2, ... Which are suitable for the collision mode, the threshold value selecting unit 6 determines the judgment result from the collision mode judging unit 5. .., an appropriate threshold value suitable for the collision mode is selected from the threshold values 1, 2 ,.

The comparing section 7 outputs the output ΔV from the integrating section 3.
And the threshold value selected by the threshold value selecting unit 6 are compared, and when the former is equal to or higher than the latter, a trigger signal is output to activate the squib activation device. As a result, the squib operates and the airbag inflates.

As described above, according to this embodiment, the threshold value suitable for the collision mode can be selected, so that the accurate collision determination can be performed.

[0024]

As is apparent from the above description, according to the present invention, the threshold value suitable for the collision mode can be selected, so that a simple and inexpensive structure using a small number of G sensors is used. There is an effect that a collision determination device can be provided. Further, there is an effect that the collision determination can be performed accurately and at an appropriate timing.

[Brief description of drawings]

FIG. 1 is a block diagram illustrating functions of an embodiment of the present invention.

FIG. 2 is a waveform diagram showing an example of an acceleration signal detected by an acceleration sensor at the time of a collision.

FIG. 3 is a waveform diagram showing an example of another acceleration signal detected by the acceleration sensor at the time of a collision.

FIG. 4 is a waveform diagram showing an example of a collision mode.

FIG. 5 is a waveform diagram showing an example of an actual acceleration signal.

FIG. 6 is a relationship diagram for obtaining a correlation value from a relative value.

[Explanation of symbols]

1 ... G sensor, 2 ... low-pass filter, 3 ... integrator, 4
... threshold value, 5 ... collision mode determination section, 6 ... threshold value selection section, 7 ... comparison section, 8 ... squib activation device

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[Procedure amendment]

[Submission date] December 8, 1992

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] 0002

[Correction method] Change

[Correction content]

[0002]

2. Description of the Related Art A conventional collision determination device integrates a G signal, which is an output of a G sensor, for a certain period of time, and when a value ΔV, which is the integrated value, which indicates a vehicle speed change amount , exceeds a predetermined reference value, a collision occurs. Then, the airbag drive device is started.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Name of item to be corrected] 0003

[Correction method] Change

[Correction content]

However, the integral value ΔV indicating the amount of change in speed of the vehicle differs depending on the position of the vehicle in which the G sensor is installed. Therefore, conventionally, a plurality of G sensors are installed in each part of the vehicle , and ΔV in each part of the vehicle is measured to determine the collision.

[Procedure 3]

[Document name to be amended] Statement

[Correction target item name] 0004

[Correction method] Change

[Correction content]

[0004]

As described above, in the conventional collision determination device, a plurality of G sensors are installed in each part of the vehicle and ΔV of each part of the vehicle is measured to judge the collision. As the collision detection algorithm becomes complicated,
There was a problem that it was an expensive system.

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0006

[Correction method] Change

[Correction content]

[0006]

In order to achieve the above object, the present invention provides a means for holding a plurality of threshold values adapted to a plurality of collision modes, and a collision mode from the characteristics of the pattern of the acceleration signal. Collision mode determining means for determining,
According collision mode determined by the collision mode determining means, is characterized from the plurality of threshold points equipped with a threshold selecting means for selecting a threshold value adapted to the collision mode.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Toshio Asami, 1-4-1, Chuo, Wako City, Saitama Prefecture

Claims (2)

[Claims] 1. A collision determination method for integrating an acceleration signal detected by an acceleration sensor mounted on a vehicle, comparing the acceleration signal with a threshold value, and determining a collision when the integrated value of the acceleration signal exceeds the threshold value. In the device, a means for holding a plurality of threshold values adapted to a plurality of collision modes, a collision mode determination means for determining a collision mode from the characteristics of the pattern of the acceleration signal, and a collision detected by the collision mode determination means. And a threshold value selecting means for selecting a threshold value suitable for the collision mode from the plurality of threshold values according to the mode. 2. The collision determination device according to claim 1, wherein the collision mode determination means includes a correlation value of a differential value of the acceleration signal with respect to a reference pattern, a degree of similarity of an area of a waveform of the acceleration signal with respect to the reference pattern, The collision determination device is configured to determine a collision mode based on at least one of a variation rate of the acceleration signal for each constant section and a frequency component of the acceleration signal.