JPH0632199A - Safety device for vehicle - Google Patents

Abstract

PURPOSE:To operate a safety device such as an air bag at a proper timing. CONSTITUTION:An output value from a G sensor GS is integrated by first and also second integration circuits SE and SF. Whether a safety device is to be operated or not is judged in a judging circuit SH based on two obtained integrated values A and B. Continuous integration and movable integration are made in the first and second integration circuits SE and SF respectively, and constitution is set so as to differ in each integration time each other.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a safety device such as an air bag which is actuated in the event of a collision to protect an occupant.

[0002]

2. Description of the Related Art Recently, there is an increasing number of recent vehicles equipped with a safety device that is activated in the event of a vehicle collision to protect an occupant. Examples of this safety device include an airbag that is deployed in the vehicle interior at the time of a collision, and a pre-tension type seat belt that is forcibly pulled (tensioned) at the time of a collision.

The above-mentioned safety device is required to operate reliably in a collision in which occupant damage is expected, but not to operate in a light collision where the bumper is slightly deformed. Therefore, it has been proposed to perform a predetermined calculation based on an output signal from a G sensor (acceleration sensor) attached to the vehicle body and determine whether to activate the safety device based on the calculation result. There is.

Japanese Unexamined Patent Publication Nos. 3-148348 and 1
Japanese Patent No. 14944 proposes to perform integration on the output signal of the G sensor and compare the integrated value with a predetermined determination level. That is, based on the integrated value, it is determined whether the collision state or the collision energy requires the safety device to be activated or not, by observing the collision type and the collision energy. Further, Japanese Patent Publication No. 59-8574 discloses a method in which the moving integration time is changed while the moving integration is performed.

[0005]

By the way, in order for the safety device to appropriately protect the occupant, it is desired to operate the safety device at an appropriate time. For example, in a high-speed frontal collision, it is required to activate the safety device earlier than in a low-speed frontal collision. Further, in the case of a pole collision in which a part of the vehicle body collides, it is desirable to operate the safety device at a relatively late time.

However, when the integration by the integrating means is set in accordance with the demand for operating the safety device at a late time, there is a sufficient demand for prompt activation of the safety device when there is a sudden G sensor output. However, if the safety device is set to be activated earlier, it becomes difficult to sufficiently satisfy the requirement to activate the safety device at a later time.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a vehicle safety device in which the safety device can be operated at an appropriate time.

[0008]

In order to achieve the above object, the present invention has the following configuration. That is, the G sensor attached to the vehicle body and the G sensor
Based on the first and second integrating means for integrating the output value of the sensor, and the integrated values obtained by the respective integrating means,
And a determination means for determining whether or not to activate the safety device for protecting the occupant, and the integration times of the integration means are set to be different from each other.

In order to make the integration time different, either one of the first integration means and the second integration means is made continuous integration,
The other can be a moving integral.

[0010]

According to the present invention described in claim 1,
By looking at the amount of impact at the time of collision by the integrated value of one of the integrating means that performs long time integration, while responding to a collision that activates the safety device at a later time, the other latest integrating means that performs short time integration It is possible to meet the demand for activating the safety device as soon as possible by obtaining an integral value in which the output value of the G sensor is emphasized more.

By adopting the structure as described in claim 2, the integration in the moving integration is performed while the impact energy from the beginning of the collision is observed by the integrated value in the continuous integration to correspond to the operation of the safety device at a later time. Depending on the value, it is possible to deal with the operation of the safety device at an early stage with emphasis on impact energy near the latest G sensor output value.

[0012]

Embodiments of the present invention will be described below with reference to the accompanying drawings. Description of FIG. 1 In FIG. 1, 1 and 2 are inflators for obtaining gas pressure for inflating and deploying an airbag, respectively, 1 for a driver airbag and 2 for a passenger airbag. Has been done. Reference numeral 3 is a battery, and 4 is an ignition switch, and the battery voltage after passing through the ignition switch 4 is boosted by a booster circuit 5. The voltage boosted by the booster circuit 5 is used for initiating the inflators 1 and 2, and a power supply path from the booster circuit 5 to the inflators 1 and 2 is connected in series with the switching transistors 6 and. 7 and the low G switch 8 are connected.

The low G switch 8 has a mechanical structure using a G ball and is fixedly installed on the vehicle body. While it is normally turned off, a relatively small G, for example, a gravitational acceleration of 4 is applied to the vehicle body. ON when 4G that doubles the acceleration occurs
It is said that. As a result, on condition that the ignition switch 4 is turned on, when the switching transistors 6 and 7 and the low G switch are turned on, the high voltage from the booster circuit 5 is applied to the inflators 1 and 2. When applied, the inflators 1 and 2 are detonated, and the corresponding airbag is inflated and deployed in the vehicle compartment.

As a power source for initiating the inflators 1 and 2, a backup power source 9 using a capacitor is configured, and the switching transistor 10 is turned on, so that the ignition switch 3 is turned off for a while. A voltage for detonation can be supplied from the backup power source to the inflators 1 and 2.

U is a control unit constituted by using a microcomputer, and its CPU is shown by reference numeral 11. Signals from the G sensor (acceleration sensor) GS mounted on the vehicle body and the monitor circuits 12 and 13 are input to the CPU 11. In addition to the booster circuit 5, the switching transistors 6, 7 and 10, the CPU 11 outputs the alarm lamp 14 and the alarm buzzer 15. The monitor circuit 12 detects abnormality such as disconnection of the power supply circuits of the inflators 1 and 2. The monitor circuit 13 detects an abnormality such as a disconnection of the power supply path to the alarm lamp 14, and when the alarm lamp 14 does not operate, the CP
U11 activates the buzzer-15. And the CPU 11
Is monitored by the watchdog timer 16.

2. Description of FIG . 2 An outline of control contents by the control unit U, that is, the CPU 11 will be described with reference to FIG. First, in P (step-same below) 1, it is determined whether or not it is a predetermined timing every 200 μsec. YES in the determination of P1
In the case of, at P2, the signal from the G sensor GS is taken in, and then at P3, by the G sensor GS, 4
It is determined whether acceleration of G or more is detected.

If the determination in P3 is YES, the calculation for the output waveform, which will be described later, is performed in P4. Then, in P5, it is determined whether or not the calculation result in P4 is equal to or greater than a predetermined determination value. If the determination in P5 is YES, in P6, the switching transistors 6 and 7 are turned on to cause the inflators 1 and 2 to detonate. After that, at P7, it is determined whether or not 300 msec has elapsed after the switching transistors 6 and 7 were turned on at P6. If NO in this determination of P7, the process returns to P6 and the switching transistor 6,
7 continues to be turned on. If the determination in P7 is YES, the switching transistors 6 and 7 are turned off, and the further detonation operation to the inflators 1 and 2 is stopped.

When the determination in P5 is NO, it is determined in P9 whether or not 200 msec has elapsed from the acceleration detection of 4G. This 200 msec is a time longer than the longest time required to deploy the airbag from the acceleration detection of 4G, that is, the time after it is confirmed that it is not necessary to deploy the airbag. This P
When the result of the determination in 9 is YES, various parameters, such as an integral value described later, are all cleared in P10.

When the determination in P3 is NO, in P11, the fault diagnosis of the control system using the monitor circuits 12 and 13 is performed. When the determination in P1 is NO, the control for boosting the booster circuit 5 is performed in P12.

Description of FIG . 3 Next, P4 and P5 of FIG. 2 will be described in detail with reference to FIG. First, after the output from the G sensor GS is passed through the low-pass filter S1, the calculation for low speed correspondence in S2 to SE and the calculation for high speed correspondence in SA and SF are performed. The calculation result for low speed is the first integrated value B
And the calculation result corresponding to the high speed is shown as the second integral value A. Then, the first integrated value B and the second integrated value A are added by the adder circuit SG, and the added value C is calculated. Finally, the determination circuit SH determines whether or not the added value C is higher than a predetermined determination level. Of course, the determination result of this determination circuit C is the determination result of P5 in FIG.

The above-mentioned calculation regarding low speed correspondence is performed as follows. First, after the low-frequency component is cut off by the high-pass filter S2, the waveform correction circuit SC performs waveform correction using an attenuation line CR described later.

Thereafter, the first integration circuit SE performs continuous integration based on the waveform after the waveform correction, and the first integration value B is calculated. In the embodiment, the integration is performed by converting the upper waveform (indicating the vehicle body deceleration) and the lower waveform (indicating the vehicle body acceleration) into absolute values with respect to the center of the waveform. Go (addition only, not subtraction).

On the other hand, the calculation for the high speed correspondence is as follows. First, the bias circuit SA calculates GL for the average acceleration when a frontal collision occurs at a low vehicle speed (speed of about 10 km / h).
It is subtracted from the output value from the G sensor GS. The processing in SA is performed to cut low vehicle speed components that do not need to operate the airbag. Then, the second integration circuit SF6 performs moving integration (interval integration) for 20 msec to calculate the second integration value A. Also in the integration by the second integration circuit SF, both the upper part and the lower part of the waveform are added so that the subtraction component is not included in the integration.

The first integrated value A and the second integrated value B are added by the adder circuit SG, and the weighting coefficient k is used to adjust the degree of importance of both integrated values A and B. Will be performed. That is, when k is set to a small value, the added value C that emphasizes the second integrated value A is obtained, and when k is set to a large value, the added value C that emphasizes the first integrated value B is obtained. It will be.

In the determination circuit SH, the added value C is compared with a predetermined determination level, and only when the added value C exceeds the determination level, it is necessary to operate the inflators 1 and 2 at the time of a collision. , The detonation signal is output.

The determination level is set to gradually increase with the passage of time. As a result, in the case of a high-speed frontal collision, the added value C exceeds the determination level at an earlier timing, and the airbag can be deployed at an earlier timing. Further, when the airbag needs to be actuated but is not a heavy collision, the added value C increases relatively slowly and the timing of exceeding the determination level is delayed, which delays the timing of deployment of the airbag. .

As described above, since the second integrating circuit SF performs the moving integration to obtain the second integrated value A using the relatively new output value of the G sensor output values, the G sensor output value suddenly changes. It becomes possible to deal with the case where the safety device is activated as soon as it becomes larger.

On the other hand, by the continuous integration by the first integrating circuit SE, the impact amount from the beginning of the collision is determined by the first integrated value B.
Therefore, it is suitable for dealing with the case where the safety device is activated at a relatively late time.

Here, the damping line CR in SC is set in order to clearly distinguish between a pole collision in which the airbag is required to be deployed and an extremely low speed frontal collision in which the airbag is not deployed. . That is, in the case of an extremely low speed frontal collision, one waveform has a relatively small peak value, but has a considerably large time width, and the vibration waveform from the G sensor gradually attenuates with the passage of time. . On the other hand, at the time of a pole collision, a single waveform peak
The value is relatively large, but the time width is small,
In addition to this, a large peak value does not appear during the deformation of the vehicle body after a relatively large peak value appears once, and when the vehicle body deformation limit is reached again, a relatively large peak value is reached again. Value appears.

Therefore, if the output value of the G sensor GS showing the above-mentioned waveform is integrated only for a predetermined time, there is not much difference between the obtained integrated value and the low-speed frontal collision and po -It becomes difficult to distinguish it from a Le collision.

On the other hand, it is considered that the waveform of the output signal of the G sensor GS is corrected for each waveform so that the peak value is attenuated according to a predetermined attenuation line CR. In this case, the integrated value obtained for one waveform after correction becomes larger when the waveform having the larger peak value is larger than the waveform having the smaller peak value (equivalent to increasing the time width of the waveform. Then, the portion shown by the broken line in the waveform after passing S3 in FIG. 3 is the integrated value). In other words, in the case of a pole collision in which a relatively large peak value appears, 1
Each waveform is modified so that the integrated value is obtained as a large one, while the waveform during a low-speed head-on collision where only a small peak value appears is the integrated value for each waveform is the attenuation line. Even if it is corrected by CR, it does not increase so much.

As a result, by continuing the integration based on the waveform corrected by the attenuation line CR,
In the case of a pole collision, a large integrated value that reliably exceeds the predetermined judgment level can be obtained within a relatively short time and when a large peak value appears again. On the contrary,
In the case of an extremely low speed frontal collision, even if the longest time required to deploy the airbag elapses, a large integral value exceeding the determination level cannot be obtained. As a result, the low-speed frontal collision and the pole collision can be clearly distinguished by using the integral value.

Of course, a large peak is sporadically caused by noise or the like.
Even if the peak value appears, the increase of the integrated value by the attenuation line CR is only for this large peak value that is sporadically, so that the integrated value is increased to a value that exceeds the predetermined judgment level as a whole. It does not increase.
The attenuation line CR can be set as linear or non-linear (time constant processing) such as exponential function.

Description of FIGS . 4 to 9 FIGS . 4 to 9 show another embodiment of the present invention and correspond to FIG. 4 to 9, the reference numerals of the circuits used are substantially the same as those in FIG. 5, so the description of each embodiment will be omitted and only the features will be described.

In the case of FIG. 6, the waveform correction circuit SC using the attenuation line CR is eliminated, and the pole collision and the extremely low speed frontal collision are distinguished only by the amplifier circuit SB. That is, the amplification in the amplifier circuit SB is exponentially performed according to the equation attached to the amplifier circuit SB shown in FIG. 5 in the embodiment. In this formula, the amplification factor becomes 1 at 15 G,
When a large G value exceeding G is input, the amplification factor is increased as the input value is increased (peak value is emphasized). Also,
When the input value is smaller than 15 G, the amplification factor is smaller than 1, and the smaller the input value, the smaller the amplification factor (substantially, this region is attenuated).

The above-mentioned setting of 15G is set in order to prevent the noise from being amplified in consideration of the peak value of around 10G which appears as noise on a rough road or the like. Therefore, 15 in the above equation is
It can be appropriately set in the range of 10 to 20, preferably 10 to 15. Of course, the amplification factor can be changed linearly.

In FIG. 6, two integrating circuits SE and S are provided.
Amplification circuit SB is used to perform amplification on both F, and in addition to distinguishing between a pole collision and an extremely low speed frontal collision, a large peak value is further emphasized to provide a safety device. It becomes possible to detect an operation request at an early stage even earlier.

In FIG. 7, in the process of moving integration, in addition to the amplification in the amplification circuit SB, the waveform correction circuit S
The peak value processing using the damping line CR at C is performed so that the safety device can be activated quickly in response to a sudden G occurrence.

In FIG. 8, the waveform correction circuit SC2 based on the attenuation line CR can be set to change the attenuation degree of the attenuation line CR so as to be stronger against noise. This change in the degree of attenuation is made as follows. That is, when the time width of one waveform is large, the degree of attenuation is made smaller than when it is small (corresponding to the emphasis of the peak value). On the other hand, when the peak value of one waveform is large, the degree of attenuation is increased as compared with the case where the peak value is small (a large peak value that causes noise is prevented from being reflected in the integrated value as much as possible).

In FIG. 9, in contrast to that of FIG.
This is preferable in that the preprocessing portions for the two integrating circuits SE and SF are shared as much as possible.

Although the embodiments have been described above, in the integration, only the upper part of the waveform (the waveform in the direction in which the vehicle body shows deceleration) is integrated with the center line of the waveform depicted in FIG. 3 as a boundary. Good. Further, two determination circuits are provided independently for the first integration circuit and the second integration circuit, and the safety device is activated when the integrated value exceeds the determination level in either one of the determination circuits. You may allow it. Further, the integration times may be made different by performing moving integration for both of the integrating means and making the moving integration times different from each other.

[Brief description of drawings]

FIG. 1 is a control system diagram showing an embodiment of the present invention.

FIG. 2 is a flow chart showing a control example of the present invention.

FIG. 3 is a block diagram showing a calculation portion and a determination portion based on a G sensor output.

FIG. 4 shows a second embodiment of the present invention and is a view corresponding to FIG.

FIG. 5 is a diagram showing how amplification is performed by the amplifier circuit shown in FIG. 4;

FIG. 6 shows a third embodiment of the present invention and is a view corresponding to FIG.

FIG. 7 shows a fourth embodiment of the present invention and corresponds to FIG.

FIG. 8 shows a fifth embodiment of the present invention and corresponds to FIG.

FIG. 9 shows a sixth embodiment of the present invention and is a view corresponding to FIG. 3.

[Explanation of symbols]

 1, 2 Inflator (for airbag) 6, 7: Switching transistor (for detonation) 11: CPU U: Control unit SE: Integrating circuit (continuous integration) SF: Integrating circuit (moving integration) SH: Judgment circuit

(72) Inventor Junichi Miyawaki, 3-1, Shinchi, Fuchu-cho, Aki-gun, Hiroshima Nardeck Co., Ltd. (72) Etsuko Yamamoto, 3-1, Shinchi, Fuchu-cho, Aki-gun, Hiroshima Prefecture Nardeck shares In the company

Claims (2)

[Claims] 1. A G sensor mounted on a vehicle body, first and second integrating means for respectively integrating output values of the G sensor, and an occupant based on the integrated values obtained by the respective integrating means. A safety device for a vehicle, comprising: a determination unit that determines whether or not to activate a protective safety device, and the integration times of the integration units are set to be different from each other. 2. The method according to claim 1, wherein one of the first integrating means and the second integrating means is a continuous integral and the other is a moving integral.