JP3126068B2 - Collision judgment device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a collision judging device,
In particular, the present invention relates to a collision determination device that can perform a collision determination early by performing a weighting process on a G signal output from an acceleration sensor (hereinafter, abbreviated as a G sensor).

[0002]

2. Description of the Related Art A conventional collision judging device integrates a G signal, which is an output of a G sensor, for a certain period of time, judges a collision when the integrated value .DELTA.V exceeds a predetermined reference value, and starts an airbag driving device. I am trying to do it.

However, the integral value ΔV indicating the deceleration of the vehicle differs depending on the position of the vehicle where 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, the conventional collision judging device has a plurality of G sensors installed in each part of the vehicle.
Since the collision is determined by measuring the integral value ΔV of each part of the vehicle, 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 apparatus and to provide a collision determination apparatus which can perform a collision determination at an early stage using a simple system.

[0006]

In order to achieve the above object, the present invention provides a differential value calculator for calculating a differential value (dG / dt) of the G signal at a predetermined time interval A; A weight determining unit that determines a weight in accordance with the magnitude of the differential value obtained by the unit; a weighting unit that adds the weight determined by the weight determining unit to the differential value; and a weighted differential value. And an integration section for integrating the time interval A
A threshold setting unit that outputs a threshold value that is updated each time a larger time interval comes, and compares the integrated value obtained by the integration unit with the threshold value output from the threshold setting unit And a squib activation device that activates a squib based on the output of the comparison unit.

[0007]

According to the present invention, the weight is determined according to the magnitude of the differential value of the G signal, and the weight is added to the G signal. Therefore, it is possible to perform a collision determination early with a simple system. There is an effect that can be.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the drawings. FIG. 1 is a block diagram illustrating functions of the present invention.

In FIG. 1, reference numeral 1 denotes a G sensor mounted on a vehicle, 2 denotes an LPF (low-pass filter) which receives a G signal detected by the G sensor 1 and 3 denotes a dG for obtaining a differential value of an output signal of the LPF 2. The / dt calculation unit 4 and the weight determination unit 4 determine the weight according to the result of the dG / dt calculation unit, and the weighting unit 5 adds the weight to the dG / dt calculation value. Reference numeral 6 denotes an integrator for integrating the weighted dG / dt operation value. A reset unit 7 outputs a reset signal when the output of the dG / dt calculation unit 3 is negative.

Reference numeral 8 denotes a time (t) measuring unit for outputting the signal A every time the time A is measured, and 9 counts the signal A.
A counter 10 that outputs a signal B every time a predetermined value is reached is a threshold value setting unit that sets a threshold value based on an input signal from the counter 9. Reference numeral 11 denotes a comparison unit that compares the output of the integration unit 6 with the threshold value set by the threshold value setting unit 10, and 12 denotes a squib activation device that inflates the airbag.

The reset signal output from the reset section 7 is input to the integrating section 6, the time (t) measuring section 8, the counter 9, the threshold value setting section 10 and the like to initialize the apparatus.

Next, the operation of this embodiment will be described.

The G signal detected by the G sensor 1 is an LPF
2 removes high frequency components. The waveform of FIG.
3 shows an example of the output waveform of the first embodiment. On the other hand, the time (t) measuring section 8 repeatedly outputs the signal A indicating the first time interval A. This signal A is input to the dG / dt calculation unit 3 and the counter 9
To enter.

Upon receiving the notification of the first time interval A from the time (t) measuring unit 8, the dG / dt calculating unit 3 calculates the change amount of the G signal in the section A. The calculated change amount is determined by the weight determination unit 4.
Is compared with the first reference threshold value α and the second reference threshold value β (where α <β). If smaller than the first reference threshold value α, no weighting is applied, and α ≦ the amount of change If <β, the first weight a, if β ≦ change amount, the second weight b (where a <b) is determined.

When the weight is determined, the weighting unit 5 performs an operation of adding the weight to dG / dt (differential value) of each section A. That is, as shown in FIG. 3A, if the change amount of the G signal in the section A is smaller than the first reference threshold α, no weighting is performed, and if α ≦ change amount <β, Same figure
As shown in (b), the first weighting a is performed and G
'. If β ≦ change amount, the second weighting b is performed and G ′ is obtained as shown in FIG. The G signal to which the weight has been added is integrated by the integrator 6. The waveforms indicated by the dotted lines in FIGS. 3B and 3C show the waveform G before weighting. FIG. 4 shows a waveform obtained by integrating the weighted waveform G ′.

(Equation 1) An example is shown. Here, k indicates the weight.

On the other hand, when receiving the notification of the first time interval A from the time (t) measuring section 8, the counter 9 counts the number of times, and counts the second time interval B (B1, B2...). measure. The threshold setting unit 10 sets the second time interval B
The thresholds (1), (2), and (3) are updated and output each time. Where threshold (1) <threshold (2) <threshold
(3).

The comparing section 11 compares the output of the integrating section 6 with the threshold values (1), (2), and (3), and outputs a squib activation signal at that time when the former becomes greater than the latter. I do. As a result, the squib activation device 12 is activated, and the airbag is inflated.

FIG. 5 shows the threshold value setting unit 10 and the comparison unit 1
3 is a waveform chart showing the operation of FIG. As shown in FIGS. 7A and 7B, the threshold value setting unit 10 sets the threshold value (1) in the B1 section, the threshold value (2) in the B2 section, and the threshold value (2) in the B3 section. Outputs the threshold value (3). Further, as shown in FIG. 5 (a), in the section B1, the integral value ΔV <the threshold value
(1) When the integral value .DELTA.V <threshold value (2) in the section B2 and the integral value .DELTA.V <threshold value (3) in the section B3, the comparator 9 outputs a positive signal and the squib is not activated. Not done. However, when the integral value ΔV ≧ threshold value (3) at time t1 in the section B3 as shown in FIG. 7B, the signal of the comparator 9 changes from positive to negative, and the squib starter 10 operates. . As a result, the airbag is inflated.

Next, an example of the operation of the above embodiment will be described in more detail with reference to the flowchart of FIG.

First, in step S1, the value S of a counter (not shown) is cleared, and it is determined in step S2 whether a predetermined time A has come. If it is determined that the predetermined time A has come, the process proceeds to step S3, where 1 is added to the counter. Then, in step S4, a G change, that is, dG / dt is calculated. In step S5, it is determined whether or not the G change obtained in step S4 is continuously positive. If the determination is negative, the process proceeds to step S6 to reset all processing data.

The reason is that when the G change is not continuously positive, the G signal shows a non-collision waveform such as a bad road.

If the determination in step S5 is affirmative, the process proceeds to step S7, where the magnitude of the G change is α ≦ G
It is determined whether or not the amount of change <β. When this determination is affirmative, the process proceeds to step S8, where a first weighting process is performed. On the other hand, when step S7 is negative, the process proceeds to step S9 to determine whether α <β ≦ G change amount is satisfied. If this determination is affirmative, the process proceeds to step S10, where a second weighting process is performed.
If the G change amount is smaller than the first reference threshold value α, the process proceeds to step S11 without any weighting.

In step S11, an integration process is performed.
ΔV is determined. Next, in step S12, it is determined whether or not ΔV is equal to or greater than the first threshold value (1). If this determination is affirmative, it is determined that a collision has occurred,
Proceeding to step S17, the output stage is started.

On the other hand, if the determination in step S12 is negative, the process proceeds to step S13, where it is determined whether or not the count value S of the counter has reached the predetermined number of times (= B1) in the time interval A. . When the determination is negative, the process proceeds to step S16, where the time A is reset,
Time measurement is started again from 0. Then, when step S2 becomes affirmative, the process proceeds to step S3, and the above-described processing is repeated.

When step S13 is affirmative, the process proceeds to step S14, where the counter is reset.
Next, proceeding to step S15, the first threshold value is set.
(1) is updated to the second threshold value (2), and it is determined whether or not ΔV is equal to or more than the second threshold value (2). If this determination is affirmative, it is determined that a collision has occurred, and the process proceeds to step S17 to start the output stage.

On the other hand, if the determination in step S15 is negative, the process proceeds to step S16, in which it is determined whether or not the count value S has counted the time interval A a predetermined number of times (= B2). When the determination is negative, the process proceeds to step S16, the time A is reset, and the time measurement is started again from 0. Note that B1 =
B2 = ... may or may not be.

Next, the effect obtained by this embodiment will be described.
This will be described with reference to FIGS.

FIG. 7A shows an example of a waveform diagram of a G signal in the case of a frontal collision, FIG. 7B shows a waveform after weighting processing, and FIG. 7C shows an integrated value ΔV. Time t in section B1
At 1 the first threshold (1) is exceeded, indicating that the squib has been activated. As a result of the present embodiment, the start of the squib can be accelerated.

FIG. 8A shows an example of a waveform diagram of the G signal when a low-speed collision occurs. FIG. 3B shows the waveform after the weighting process, and FIG. 3C shows that the integrated value ΔV is (B1 + B
At time t2 when (2 + B3 + B4) .times.A (time) comes, it exceeds the fourth threshold value (4), indicating that the squib has been started.

FIG. 9 (a) shows an example of a waveform diagram of the G signal at the time of non-collision, for example, running on a rough road, and FIG. 9 (b) shows a waveform after weighting. In this embodiment, when dG / dt becomes negative, all the processing data is reset. Therefore, the integral value ΔV is reset every time dG / dt becomes negative, as shown in FIG. , A first threshold value (1). In this case, the integral value ΔV is equal to the first threshold value.
Since (1) is not exceeded, the squib will not be activated.

The weight determining unit 4 of the above-described embodiment.
Is weighted in two steps a and b, but the present invention is not limited to this, and it is needless to say that weighting in three or more steps may be performed.

In the above embodiment, the counter is used to set B
1 × A (time), (B1 + B2) × A (time),... Were measured, but the present invention is not limited to this, and it is a matter of course that the measurement may be performed by other means such as a timer. It is.

[0033]

As is clear from the above description, according to the present invention, the differential value is weighted at the time of a collision such as a head-on collision, so that the determination of the collision can be made faster by using a simple system. There is an effect that can be. In addition, at the time of non-collision, the weighting is not performed, so that there is an effect that a collision is not erroneously determined.

[Brief description of the drawings]

FIG. 1 is a functional block diagram of one embodiment of the present invention.

FIG. 2 is a waveform diagram of a G signal detected by a G sensor and from which high-frequency components have been removed.

FIG. 3 is an explanatory diagram of an operation of a weight determining unit and a weight adding unit in FIG. 1;

FIG. 4 is an explanatory diagram of an operation of the integration unit in FIG. 1;

FIG. 5 is an explanatory diagram of an operation of the comparison unit in FIG. 1;

FIG. 6 is a flowchart for explaining the operation of one embodiment of the present invention.

FIG. 7 is an explanatory diagram of an operation of a frontal collision system.

FIG. 8 is an explanatory diagram of the operation of the medium-low speed collision system.

FIG. 9 is a diagram illustrating the operation of a non-collision system.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... G sensor, 3 ... dG / dt calculation part, 4 ... weight determination part, 5 ... weight addition part, 6 ... integration part, 7 ... reset part, 8 ... time (t) measurement part, 9 ... counter, 10 ... Threshold setting unit, 12: squib activation device

────────────────────────────────────────────────── ─── Continuation of front page (56) References JP-A-3-238358 (JP, A) JP-A-3-114944 (JP, A) JP-A-3-235739 (JP, A) 220044 (JP, A) JP-A-5-313753 (JP, A) JP-A-5-278559 (JP, A) JP-A-3-43058 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) G01P 15/00 B60R 21/32

Claims (2)

(57) [Claims] An apparatus for determining a collision using a detection signal (G signal) of an acceleration sensor mounted on a vehicle, wherein a differential value (dG / dt) of the G signal is calculated at a predetermined time interval A. A value calculation unit, a weight determination unit that determines weight according to the magnitude of the differential value obtained by the calculation unit, and a weight addition unit that adds the weight determined by the weight determination unit to the differential value. An integration unit that integrates the weighted differential value; a threshold setting unit that outputs a threshold that is updated each time a time interval greater than the time interval A comes; an integration obtained by the integration unit A comparison unit that compares a value with a threshold value output from the threshold value setting unit; and a squib activation device that activates a squib based on an output of the comparison unit. When it exceeds, Collision determination apparatus characterized by the activation apparatus so as to boot. 2. A collision judging device according to claim 1, further comprising means for initializing a collision judging process of said collision judging device when said differential value calculating section detects a negative differential value. Characteristic collision determination device.