JPH0632200A - Safety device for vehicle - Google Patents

Abstract

PURPOSE:To properly set the operation timing for a safety device such as an air bag, and also clearly distinguish a collision condition in which whether the safety device is to be operated or not. CONSTITUTION:An output value from a G sensor GS is amplified at a larger amplification factor for a waveform having a larger peak value compared with a waveform having a smaller peak value. An output value after amplification is integrated in an integration circuit SF 1, and whether a safety means is to be operated or not is judged with a judging circuit SH based on this integrated value.

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 airbags and the like are required to be reliably actuated at the time of a collision in which occupants are expected to be damaged, but not to be actuated at the time of a light collision in which the bumper is slightly deformed. Therefore, it is 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 operate the airbag or the like based on the calculation result. ing.

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 airbag or the like to be actuated or not to be actuated by checking the collision mode and the collision energy.

[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 the case of a high-speed frontal collision, it is required to activate the safety device early, and in the case of a pole collision that causes a collision of a part of the vehicle body, the safety device is activated relatively late. That is what is desired.

On the other hand, it is desirable to prevent the safety device from operating in the case of a low-speed frontal collision where the bumper may be deformed. However, it is difficult to clearly distinguish between a pole collision in which the safety device is required to operate and a low-speed frontal collision in which the safety device is not required to operate.

Explaining this point in detail, since the low-speed frontal collision and the pole collision at the normal traveling speed are not so different in the integrated values when the integrated values at a predetermined time are compared.
It is difficult to make a clear distinction. More specifically, regarding the waveform of the output signal of the G sensor obtained in the case of a low-speed frontal collision, a waveform having a relatively small peak value but having a relatively large time width appears continuously for a considerably long time. However, as a result, the integrated value becomes considerably large. On the other hand, in the waveform of the output signal of the G sensor obtained in the case of a pole collision, a relatively large peak value appears, but the time width is quite small. The value will not change.

In order to distinguish between a low speed frontal collision and a pole collision, the magnitude relationship between the peak values of the waveform of the G sensor output value is observed, that is, a pole collision occurs when a large peak value appears. Therefore, it can be considered that it is necessary to operate the airbag or the like. However, the magnitude of the peak value obtained at the time of a pole collision is such a level that it appears even when driving on a bad road, and it is incorrect to simply add this peak value. Therefore, the possibility of operating an airbag or the like becomes extremely high.

Therefore, an object of the present invention is to appropriately set the operation timing of the safety device in accordance with the magnitude of the impact and to clearly distinguish the collision state whether the safety device is operated or not. It is to provide a safety device for the vehicle.

[0010]

In order to achieve the above object, the present invention has the following configuration. That is, a G sensor mounted on the vehicle body, an amplification means for amplifying the output value of the G sensor with a larger amplification factor than a waveform with a small peak value for a waveform with a large peak value; A first that integrates the output value after amplification by the amplification means
It is configured to include an integrating means and a determining means for determining whether or not to activate the safety device for occupant protection based on the first integrated value integrated by the first integrating means.

Bias means for subjecting the output value amplified by the amplifying means to a predetermined bias processing is further provided, and the first integrating means integrates the output value after the bias processing. Can be

A second integrating means for integrating the output value of the G sensor without amplifying it by the amplifying means,
The determining means may perform determination based on both integrated values of the first integrated value integrated by the first integrating means and the second integrated value integrated by the second integrating means. .

[0013]

According to the present invention described in claim 1,
The amplifying means obtains an integrated value in a manner in which the peak value of the G sensor output value is emphasized, so that a pole collision in which a relatively large peak value appears and a large peak value occur. It is possible to operate the safety device at an appropriate time according to the magnitude of the peak value, that is, the impact at the time of collision, while clearly distinguishing the low-speed front light collision that does not appear by looking at the integral value. it can. Of course, the integral value is not sharply increased by a large peak value as noise that appears when driving on a rough road, so the safety device is erroneously caused by this single peak value. It is also possible to prevent the situation where it is activated.

By adopting the structure as described in claim 2, it is possible to enhance only the high peak value and enhance the above effect.

With the structure as described in claim 3, the functions of the two integrating means are divided so that the quick collision and the buffer collision can be distinguished from each other, that is, the safety device can be activated early or late. It can be more clearly and appropriately activated.

[0016]

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, is fixedly installed on the vehicle body, and is normally turned off. 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.

When 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 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 FIGS . 3 and 4 FIG . 3 shows a waveform of the output value of the G sensor GS at the time of a low speed frontal collision, and FIG. 4 shows the waveform of the G sensor GS at the time of a pole collision during normal traveling. The waveform of the output value of is shown. This Figure 3,
As can be understood by comparing FIG. 4, in the case of a low-speed frontal collision, one waveform has a relatively small peak value, but a considerably large time width. On the other hand,
In the case of a pole collision, the peak value of one waveform is relatively large, but the time width is small.

Therefore, if the output values of the G sensor GS having the above-mentioned waveform are integrated for a predetermined time, the integrated value obtained in the case of FIG. 3 and the integrated value obtained in the case of FIG. There is no significant difference between and, which makes it difficult to distinguish between a low speed frontal collision and a pole collision.

Description of FIG . 5 Next, P4 and P5 of FIG. 2 will be described in detail with reference to FIG. First, the output signal (output value) from the G sensor GS is passed through the low-pass filter S0. In the embodiment, the processing by the filter S0 is divided into the first processing by the low-pass filter and the second processing by the high-pass filter.
This is done in stages. After that, the output signal from the G sensor GS is amplified by the amplifier circuit SB as described later. Further, the bias circuit SA subtracts from the output value from the G sensor GS by GL, which is the average acceleration when a head-on collision occurs at a low vehicle speed (speed of about 10 km / h). The processing in SA is performed to cut low vehicle speed components that do not need to operate the airbag.

After the processing in the bias circuit SA, a calculation regarding collision type information (SC and SF1) and a calculation regarding speed information (SF2) are performed. The calculation result of the collision type information is shown as a first integrated value B, and the calculation result of the vehicle speed (vehicle speed change) information is shown as a second integrated 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.

In the embodiment, amplification by the amplifier circuit SB is shown in FIG.
The exponential function is performed according to the equation attached to the amplifier circuit SB shown in FIG. In this formula, 15G
At that point, the amplification factor becomes 1 and a large G exceeding 15G
When is input, the amplification factor is increased as the input value is increased (peak value is emphasized). Further, when the input value is smaller than 15 G, the amplification factor is smaller than 1, and the smaller the input value is, the smaller the amplification factor is (substantially this region is attenuation).

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.

The above-mentioned calculation regarding the collision form information is performed as follows. First, in the waveform correction circuit SC, the attenuation line CR is used to perform waveform correction by emphasizing the peak value. This waveform correction is performed by the attenuation line CR which is set so that the peak value of each waveform is attenuated with a predetermined attenuation degree. In such an attenuation line CR, a waveform having a large peak value but a small time width is maintained while maintaining the peak value as it is.
It is a correction to increase the time width according to the size of the black value. The attenuation line CR can be set linearly or non-linearly like an exponential function.

Thereafter, the first integrating circuit SF1 performs moving integration for 40 msec on the basis of the waveform after the waveform correction to calculate the first integrated value B. In addition,
In the embodiment, at the time of integration, with the center of the waveform as a boundary,
The upper waveform (representing the vehicle body deceleration) and the lower waveform (representing the vehicle body acceleration) are converted into absolute values and integrated (addition only, not subtraction).

On the other hand, in the calculation regarding the vehicle speed information, the second integration circuit SF2 performs the moving integration for 40 msec to calculate the second integration value A. This second integrating circuit S
Also in the integration by F2, 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 also 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 judgment circuit SH, a predetermined judgment level is compared with the added value C, and only when the added value C exceeds the judgment level, it is necessary to operate the inflators 1 and 2 at the time of a collision. , The detonation signal is output. In addition,
The determination level is set as a predetermined constant value.

In the example of FIG. 5 described above, the first integrating circuit SF
A large number of preprocessing portions of the first and second integration circuits SF2 can be used in common to simplify the calculation. Moreover, the calculation time can be shortened by using the moving integral for both integrals. In addition, in FIG. 5, the second integrating circuit SF2 may be configured to perform continuous integration. In this case, it is preferable to change the determination level in the determination circuit SH so that it gradually increases with the passage of time.

Description of FIGS . 6 to 12 FIGS . 6 to 12 show another embodiment of the present invention and correspond to FIG. 6 to 12
In FIG. 5, the reference numerals of the circuits used are substantially the same as those in FIG. 5 (however, the continuous integration is indicated by the reference numeral SE and the moving integral is indicated by the reference numeral SF). Then, 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 amplification circuit SB is used exclusively to avoid the adverse effect of a large peak value as a noise that occurs sporadically. In addition, in FIG.
Both integrals may both be moving integrals. In this case, the integral operation is a single logic, which facilitates the setting of the control program.

In FIG. 7, since there is only one integrating circuit, the calculation time can be shortened while the logic is simple as a whole.

In FIG. 8, the advantage of FIG. 7 is sacrificed, but the advantage of function sharing by the two integrating circuits is obtained.

In FIG. 9, it is advantageous for surely and promptly determining a heavy collision which requires the airbag to be operated absolutely surely and early. Note that FIG.
In, both integrals may be moving integrals, and in this case, the calculation logic of integrals can be made common.

In FIG. 10, the waveform correction circuit SC2 based on the attenuation line CR can be set to change the attenuation degree of the attenuation line CR to make it 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. 10, both integrals may be moving integrals.

In FIG. 11, it is preferable to the one shown in FIG. 10 in that the preprocessing portions for the two integrating circuits are shared as much as possible. In FIG. 11, both integrals may be moving integrals.

FIG. 12 is preferable for simplifying the logic as much as possible while obtaining the advantages of FIG.

Although the embodiments have been described above, in the integration, only the upper portion 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. 5 as a boundary. Good.

[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 diagram showing an output waveform of a G sensor that appears when a low-speed frontal collision occurs.

FIG. 4 is a diagram showing an output waveform of a G sensor that appears at the time of a pole collision.

FIG. 5 is a block diagram showing a calculation portion and a determination portion based on a G sensor output.

FIG. 6 is a view showing a second embodiment of the present invention and corresponds to FIG.

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

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

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

FIG. 10 shows a sixth embodiment of the present invention and corresponds to FIG.

FIG. 11 shows a seventh embodiment of the present invention and is a view corresponding to FIG.

FIG. 12 shows an eighth embodiment of the present invention and corresponds to FIG.

[Explanation of symbols]

 1, 2 Inflator (for airbag) 6, 7: Switching transistor (for detonation) 11: CPU U: Control unit GS: G sensor SA: Bias circuit SB: Amplifying circuit SF: Integrating circuit SF1: Integrating circuit SF2 : Integrator circuit SE: Integrator circuit SH: Judgment circuit

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kazuo Yutomo 3-1, Shinchi, Fuchu-cho, Aki-gun, Hiroshima Nardeck Co., Ltd. (72) Masami Sato 3-3 Shinchi, Fuchu-cho, Aki-gun, Hiroshima Nardeck Co., Ltd.

Claims (3)

[Claims] 1. A G sensor mounted on a vehicle body, and an amplifying means for amplifying an output value of the G sensor with a larger amplification factor for a waveform having a larger peak value than a waveform having a smaller peak value. A first integration means for integrating the output value after amplification by the amplification means, and a first integration value integrated by the first integration means,
A safety device for a vehicle, comprising: a determination unit that determines whether to activate a safety device for protecting an occupant. 2. The bias unit according to claim 1, further comprising a bias unit for performing a predetermined bias process on the output value amplified by the amplifying unit, and the first integrating unit after the bias process. The one that integrates the output value. 3. The second integration means according to claim 1, further comprising second integration means for integrating the output value of the G sensor without amplifying it by the amplification means, and the determination means is integrated by the first integration means. A determination is made based on both integrated values of the first integrated value and the second integrated value integrated by the second integrating means.