JP3342889B2 - Vehicle safety devices - Google Patents

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 activated in a collision to protect an occupant.

[0002]

2. Description of the Related Art In recent vehicles, there has been a tendency to increase the number of vehicles equipped with a safety device which is activated at the time of a vehicle collision to protect occupants. Examples of the safety device include an airbag that is deployed in a vehicle cabin at the time of a collision and a pretension type seat belt that is forcibly pulled (tensioned) at the time of a collision.

[0003] The above-mentioned safety device is required to be reliably operated at the time of a collision in which the occupant may be damaged, but not to be operated at the time of a light collision in which the bumper is slightly deformed. For this reason, 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 to determine whether to activate the safety device based on the calculation result. I have.

JP-A-3-148348, JP-A-1
Japanese Patent Application Laid-Open No. 14944 proposes integrating an output signal of a G sensor and comparing the integrated value with a predetermined determination level. That is, based on the integrated value, the collision state and the collision energy are determined by determining the collision state and the collision state in which the safety device needs to be activated or not. Further, Japanese Patent Publication No. 59-8574 discloses a technique in which a moving integration is performed while the moving integration time is changed.

[0005]

In order to properly protect the occupant by the safety device, it is desired to operate the safety device at an appropriate time. For example, in a high-speed head-on collision, it is required to operate the safety device earlier than in a low-speed head-on collision. Also, in the case of a pole collision in which a collision occurs with a part of the vehicle body, it is desired to operate the safety device at a relatively late time.

However, when the integration by the integrating means is set in accordance with a request to activate the safety device at a later time, it is sufficient to request that the safety device be activated immediately when there is an abrupt G sensor output. If the safety device cannot be satisfied, and if the safety device is set to be operated quickly, it is difficult to sufficiently satisfy the demand for operating the safety device at a later time.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a vehicle safety device capable of operating the safety device at an appropriate time.

[0008]

Means for Solving the Problems To achieve the above object, the present invention has the following configuration. That is, a G sensor attached to the vehicle body, a predetermined acceleration determining means for determining whether or not an output value from the G sensor has reached a predetermined acceleration or more, and a first sensor for integrating the output value of the G sensor. An integrating means, a second integrating means, and a determining means for determining whether to activate a safety device for protecting an occupant based on an integrated value and a determination level obtained by each of the integrating means, One of the first integration means and the second integration means performs continuous integration that is performed continuously from the predetermined acceleration determination on condition that a predetermined acceleration determination is made based on the predetermined acceleration determination means. And the other of the first integration means and the second integration means performs integration for a predetermined time from the predetermined acceleration determination on the condition that a predetermined acceleration determination is made based on the predetermined acceleration determination means. Repetitive moves Integral is set, the determination level of the determination means is set to increase as time passes, and the determination means calculates a continuous integration value calculated by the one integration means, The apparatus is set to determine whether or not the determination level is exceeded, based on the latest movement integration value calculated by the other integration means. is there.

[0009]

[0010]

According to the present invention, the latest G sensor can be used by the integral value of the moving integral while corresponding to the operation of the safety device at a later time by seeing the impact energy from the beginning of the collision by the integral value of the continuous integral. It is possible to cope with the operation of the safety device at an early stage in which the impact energy near the output value is emphasized.

[0011]

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the accompanying drawings. In FIG. 1, reference numerals 1 and 2 denote inflators for obtaining gas pressure for inflating and deploying an airbag, respectively, 1 for an airbag for a driver seat, and 2 for an airbag for a passenger seat. Have been. Reference numeral 3 denotes a battery, and reference numeral 4 denotes an ignition switch. 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 detonating the inflators 1 and 2, and the power supply path from the booster circuit 5 to the inflators 1 and 2 is connected in series with the switching transistor 6. 7 and a 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, and is normally turned off. ON when 4G with double acceleration occurs
It is said that. Thus, on condition that the ignition switch 4 is turned on, when the switching transistors 6, 7 and the low G switch are turned on, respectively, the high voltage from the booster circuit 5 is applied to the inflators 1, 2. When applied, the inflators 1 and 2 are detonated, and the corresponding airbag is inflated and deployed in the vehicle interior.

A backup power supply 9 using a capacitor is provided as a power supply for initiating the inflators 1 and 2, and the switching transistor 10 is turned on, so that even if the ignition switch 3 is turned off, it will remain for a while. The initiating voltage can be supplied to the inflators 1 and 2 from the backup power supply.

U is a control unit constructed using a microcomputer, and its CPU is indicated by reference numeral 11. Signals from a G sensor (acceleration sensor) GS attached to the vehicle body and monitor circuits 12 and 13 are input to the CPU 11. Further, the CPU 11 outputs signals to an alarm lamp 14 and an alarm buzzer 15 in addition to the booster circuit 5, the switching transistors 6, 7, and 10. The monitor circuit 12 detects an 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 a 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.

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

If the determination in P3 is YES, a calculation for an output waveform described later is performed in P4. Then, in P5, it is determined whether 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, 7 are turned on, thereby initiating the inflators 1, 2. Thereafter, in P7, it is determined whether or not 300 msec has elapsed after the start of turning on the switching transistors 6 and 7 in P6. If the determination in P7 is NO, the process returns to P6, and the switching transistor 6,
7 is kept ON. If the determination in P7 is YES, the switching transistors 6, 7 are turned off, and the further initiating operation on the inflators 1, 2 is stopped.

If the determination in P5 is NO, it is determined in P9 whether 200 msec has elapsed since the 4G acceleration was detected. This 200 msec is a time longer than the maximum time required to deploy the airbag from the 4G acceleration detection, that is, a time after it is confirmed that there is no need to deploy the airbag. This P
If the determination in step 9 is YES, in P10, all the parameters, for example, the integral values described later are all cleared.

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

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, calculations for low speed response in S2 to SE and calculations for high speed response in SA and SF are performed. The calculation result corresponding to the low speed is the first integral value B
And the calculation result corresponding to the high speed is shown as a second integral value A. Then, the first integrated value B and the second integrated value A are added by the adding circuit SG, and the added value C is calculated. Finally, the determination circuit SH determines whether the added value C is greater than a predetermined determination level. Of course, the result of determination by the determination circuit C is the result of determination at P5 in FIG.

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

Thereafter, continuous integration is performed by the first integration circuit SE based on the corrected waveform, and a first integration value B is calculated. In the embodiment, at the time of integration, the upper waveform (indicating the vehicle body deceleration) and the lower waveform (indicating the vehicle acceleration) are each converted to an absolute value and integrated at the center of the waveform. Go (addition only, not subtraction).

On the other hand, the calculation relating to the high-speed support is performed by the bias circuit SA by the amount of GL, which is the average acceleration at the time of a frontal collision 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 moving integration (interval integration) of 20 msec is performed by the second integration circuit SF.
Is performed, and the second integral value A is calculated. In the integration by the second integration circuit SF, both the upper part and the lower part of the waveform are added so that no subtraction component is included in the integration.

The first integrated value A and the second integrated value B are added by an adder circuit SG, and a process for determining how much importance is given to both the integrated values A and B by a weighting coefficient k is also included. It is done. That is, by setting k to a small value, an added value C in which the second integrated value A is more emphasized is obtained, and by setting k to a large value, an added value C in which the first integrated value B is more emphasized is obtained. Will be.

In the judgment circuit SH, the added value C is compared with a predetermined judgment level, and only when the added value C exceeds the judgment level is it necessary to operate the inflators 1 and 2 in a collision. , A firing signal is output.

The judgment level is set so as to gradually increase as time passes. Thus, in the case of a high-speed head-on collision, the added value C exceeds the determination level earlier in time, and the airbag can be deployed earlier. When the airbag needs to be activated but is not in a heavy collision, the added value C increases relatively slowly, and the time when the airbag exceeds the determination level is delayed, so that the time when the airbag is deployed is delayed. .

As described above, the second integration circuit SF performs the moving integration to obtain the second integration value A using a relatively new output value among the G sensor output values. Since the two integral values A are accurately reflected, it is possible to cope with a case where the output value of the G sensor suddenly increases and the safety device is operated quickly.

On the other hand, by the continuous integration by the first integration circuit SE, the impact amount from the beginning of the collision is reduced to the first integration value B.
This is suitable for dealing with a case where the safety device is operated at a relatively late time.

Here, the setting of the damping line CR in the SC is made in order to clearly distinguish between a pole collision required to deploy the airbag and a very low-speed frontal collision without deploying the airbag. . That is, in the case of an extremely low-speed frontal collision, each waveform has a relatively small peak value but a considerably large time width, and the vibration waveform from the G sensor gradually decreases with time. . On the other hand, in the event of a pole collision, the peak of one waveform
The value is relatively large, but the duration is small,
In addition to this, once the relatively large peak value appears, the deformation of the vehicle body proceeds, so that no large peak value appears during this period, and the relatively large peak value is again reached when the deformation limit of the vehicle body is reached. Value appears.

Therefore, if the output value of the G sensor GS having the above-mentioned waveform is integrated only for a predetermined time, there is not much difference between the integrated value and the low-speed head-on collision. -It is difficult to distinguish between collisions.

On the other hand, it is considered that the waveform of the output signal of the G sensor GS is modified such that the waveform is attenuated from the peak value in accordance with a predetermined attenuation line CR for each waveform. In this case, the integrated value obtained for one corrected waveform is larger for a waveform having a large peak value than for a waveform having a small peak value (corresponding to an increase in the time width of the waveform). Then, a portion indicated by a broken line in the waveform after passing through the SC in FIG. 3 is an integrated value). In other words, in the case of a pole collision where a relatively large peak value appears, 1
In the case of a low-speed frontal collision in which only a small peak value appears, the integral value for each waveform is corrected so that the integral value is obtained as a large value for each waveform. Even if the correction is made by the 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 event of a pole collision, a large integrated value that reliably exceeds a predetermined determination 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 head-on collision, a large integral value exceeding the above-mentioned determination level cannot be obtained even after the maximum time required for deploying the airbag has elapsed. As a result, the low-speed head-on collision and the pole collision can be clearly distinguished using the integrated value.

Of course, a large peak
Even if the peak value appears, the increase of the integral value due to the attenuation line CR is only for this single large peak value, so that the integral value is increased to a value exceeding a predetermined judgment level as a whole. It does not increase.
Note that the attenuation line CR can be set as linear or non-linear (exponential function) or other non-linear (time constant processing).

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 that the overall description in 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 front collision are distinguished solely by the amplification circuit SB. That is, in the embodiment, amplification in the amplifier circuit SB is performed exponentially according to the equation added to the amplifier circuit SB shown in FIG. In this equation, the amplification factor becomes 1 at 15G, and 15
When a large G exceeding G is input, the amplification factor increases as the input value increases (peak value is emphasized). Also,
When the input value is smaller than 15 G, the amplification factor is smaller than 1, and as the input value is smaller, the amplification factor becomes smaller (substantially, this region is attenuated).

The above setting of 15G is set so as not to amplify this noise in consideration of a peak value that appears as noise sporadically on a rough road or the like is around 10G. 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 change of the amplification factor can also be performed linearly.

In FIG. 6, two integrating circuits SE, S
Amplification is performed for both F by using an amplification circuit SB. In addition to the distinction between a pole collision and a very low-speed frontal collision, a large peak value is emphasized more and a safety device is provided. The operation request at an earlier time can be detected earlier.

In FIG. 7, in the process of moving and integrating, in addition to the amplification in the amplification circuit SB, the waveform correction circuit S
The peak value processing using the attenuation line CR at C is performed so that the safety device can be operated quickly in response to the sudden generation of G.

In FIG. 8, the waveform correction circuit SC2 based on the attenuation line CR can be set to change the degree of attenuation of the attenuation line CR so as to be stronger against noise. This change in the degree of attenuation is performed 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 emphasis of a peak value). On the other hand, when the peak value of one waveform is large, the degree of attenuation is increased as compared with when the peak value is small (so that a single large peak value serving as noise is not reflected in the integral value as much as possible).

In FIG. 9, the structure shown in FIG.
This is preferable in that the preprocessing portions for the two integration circuits SE and SF are made as common as possible.

Although the embodiment has been described above, only the upper part of the waveform (the waveform in the direction in which the vehicle body shows the deceleration) is integrated with respect to the center line of the waveform shown in FIG. Is also good. Further, two judgment circuits are provided independently for the first integration circuit and for the second integration circuit, and the safety device is activated when the integration value exceeds the judgment level in one of the judgment circuits. You may make it do.

[Brief description of the drawings]

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

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

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

FIG. 4 is a view showing a second embodiment of the present invention and corresponding to FIG. 3;

FIG. 5 is a diagram showing a state of amplification of the amplifier circuit shown in FIG. 4;

FIG. 6 is a view showing a third embodiment of the present invention and corresponding to FIG. 3;

FIG. 7 is a view showing a fourth embodiment of the present invention and corresponding to FIG. 3;

FIG. 8 is a view showing a fifth embodiment of the present invention and corresponding to FIG. 3;

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

[Explanation of symbols]

 1: 2: inflator (for airbag) 6,7: switching transistor (for detonation) 11: CPU U: control unit SE: integration circuit (continuous integration) SF: integration circuit (moving integration) SH: judgment circuit

Continuing from the front page (72) Inventor Junichi Miyawaki 3-1, Fuchu-cho, Shinchu, Aki-gun, Hiroshima Narudec Co., Ltd. (72) Inventor Etsuko Yamamoto 3-1, Shinchi, Fuchu-cho, Aki-gun, Hiroshima Narudec Co., Ltd. (56) References JP-A-4-325349 (JP, A) JP-A-3-208748 (JP, A) JP-A-5-201307 (JP, A) JP-A-6-1199 (JP, A) JP-A-1-168545 (JP, A) JP-A-3-114944 (JP, A) JP-A-5-60777 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B60R 21 / 16-21/32

Claims (1)

(57) [Claims] 1. A G sensor mounted on a vehicle body and an output value from the G sensor reaches a predetermined acceleration or more.
A predetermined acceleration determining means for determining whether or not each of them is integrated; a first integrating means and a second integrating means for respectively integrating the output values of the G sensor; and an integration value obtained by each of the integrating means and a determination level. , and a determination means for determining whether or not to operate the safety device for passenger protection, one of the first integration means and second integration means, before
The predetermined acceleration is determined based on the predetermined acceleration determining means.
Was possible on condition that is being configured for continuous integration continuously performed from the predetermined acceleration determining, the other of said first integration means and second integration means, the predetermined pressure
The predetermined acceleration is determined based on the speed determination means
Is set so as to perform a moving integration that repeats integration for a predetermined time from the predetermined acceleration determination , and the determination level of the determination unit increases with time.
And the determination means determines a previous integration value based on the continuous integration value calculated by the one integration means and the latest moving integration value calculated by the other integration means.
A safety device for a vehicle, wherein the safety device is set so as to determine whether or not a vehicle has exceeded the determination level .