JP2002059805A - Start controller for air bag device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a start controller of an air bag device having thresholds for starting an air bag varied according to an impact applied to the front part of a body capable of avoiding the air bag device to be started easily, even when the impact is large when a vehicle travels on a rough road. SOLUTION: A satellite sensor disposed at the front part of the body outputs two deceleration signals with different smoothnesses according to the impact acting on the front part of the body by two low pass IIR filters having the cut-off frequencies different from each other. Based on the deceleration signals, an ECU detects a deceleration with a lower smoothness and a deceleration with a higher smoothness. When the deceleration with the higher smoothness exceeds a specified value, a threshold variation pattern for starting the air bag device is varied according to the deceleration with the low smoothness. When the deceleration with the high smoothness does not exceed the specified value, the threshold variation pattern is maintained on a Hi map independently of the deceleration with the low smoothness.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an activation control device for an airbag device, and more particularly to an airbag device suitable for appropriately activating an airbag device for protecting an occupant in the event of a vehicle collision. And a startup control device.

[0002]

2. Description of the Related Art Conventionally, for example, Japanese Patent Application Laid-Open No.
As disclosed in Japanese Patent No. 57, there is provided a floor sensor which is disposed in a floor tunnel of a vehicle body and outputs a signal in accordance with an impact applied to the site, wherein a parameter based on an output signal of the floor sensor exceeds a threshold value. There is known an activation control device of an airbag device for deploying an airbag to a vehicle. This device is provided with a satellite sensor that is provided at the front of the vehicle body and outputs a signal according to an impact applied to the portion, and the impact applied to the front of the vehicle detected based on the output signal of the satellite sensor is large. As the threshold value decreases, the threshold value decreases. Therefore, the greater the impact applied to the front part of the vehicle body, the more easily the airbag is deployed. Therefore, according to the above-described conventional device, the airbag device that protects the occupant can be properly activated.

[0003]

By the way, a vehicle sometimes receives a large impact when traveling on a rough road as in the case of a collision. In the above-described conventional device, when such a situation occurs, a large impact is detected based on the output signal of the satellite sensor even though the vehicle does not collide, and the threshold for deploying the airbag is detected. The amount of decrease in the value increases. For this reason, in the above-described conventional device, the airbag may be easily deployed even when the vehicle travels on a rough road, and the airbag device may not be able to be properly activated.

[0004] The present invention has been made in view of the above-mentioned point, and has a structure in which a predetermined threshold value for activating an airbag is changed according to the magnitude of an impact applied to a front portion of a vehicle body. It is an object of the present invention to provide an activation control device for an airbag device that can prevent the airbag device from being easily activated when the vehicle travels on a rough road even if the impact is large.

[0005]

The above object is achieved by the present invention.
As described in the above, a first sensor that is disposed at a predetermined position in the vehicle body and outputs a signal corresponding to an impact applied to the vehicle, and a parameter based on an output signal of the first sensor sets a predetermined threshold value. An activation control device for activating the airbag device when the air pressure exceeds the threshold value, wherein the activation control device for the airbag device includes: And a second sensor for outputting a signal corresponding to the first and second signals through two filters having different cutoff frequencies, respectively, and a signal output through the filter having a higher cutoff frequency among the signals output by the second sensor. Threshold value changing means for changing the predetermined threshold value in accordance with the threshold value; and a signal output from the second sensor, which is output through the filter having a lower cutoff frequency. A bad road discriminating means for discriminating whether or not the vehicle is traveling on a rough road, and the threshold value when the bad road discriminating means determines that the vehicle is traveling on a bad road. A change prohibition unit that prohibits a change of the predetermined threshold value in accordance with a signal output through the filter having a high cutoff frequency by a change unit. Achieved.

According to the first aspect of the present invention, the second sensor outputs a signal corresponding to an impact applied to the vehicle via two filters having different cutoff frequencies. A signal output through a filter with a high cutoff frequency and a signal output through a filter with a low cutoff frequency have different amplitude characteristics and phase characteristics. in this case,
The signal output through the filter with a high cutoff frequency is
7 shows a waveform that is closer to the original waveform of an impact applied to a vehicle than a signal output through a filter having a low cutoff frequency. In the present invention, the predetermined threshold value for starting the airbag device is changed according to a signal output through a filter having a high cutoff frequency among the signals output from the second sensor. For this reason, the predetermined threshold value for the activation of the airbag device is changed according to a value approximate to the impact actually applied to the vehicle, so that the appropriateness of the activation of the airbag device is accurately and appropriately determined. You.

By the way, the impact applied to the vehicle during a collision lasts for a relatively long time, while the impact applied to the vehicle does not continue for a long time when traveling on a rough road. That is, when traveling on a rough road, the time it takes to reduce the impact after the impact is applied is shorter than during the collision. Therefore, if a filter that attenuates a signal corresponding to a short-period (that is, high-frequency) impact that may occur when traveling on a rough road is used, if a large impact occurs due to a collision, the impact is output to the output side of the filter. In the case where a large impact occurs due to running on a rough road, only a signal that is attenuated more than a signal corresponding to an actual impact can appear. Therefore, it is possible to accurately determine whether or not the vehicle is traveling on a rough road, based on a signal output through a filter having a low cutoff frequency.

When it is determined that the vehicle is traveling on a rough road, the change of the predetermined threshold value according to a signal output through a filter having a high cutoff frequency is prohibited. For this reason, even in a situation where a large impact occurs at the position where the second sensor is provided, if the impact is caused by running on a rough road, the predetermined threshold value may be too small. Be avoided. Therefore, according to the present invention, it is possible to prevent the airbag device from being easily activated even when a large impact is applied to the front portion of the vehicle body when traveling on a rough road.

Further, the above object is achieved by a first sensor disposed at a predetermined position in a vehicle body and outputting a signal corresponding to an impact applied to the vehicle, and a first sensor. Activation control means for activating the airbag device when a parameter based on the output signal of the output signal exceeds a predetermined threshold value.
A second sensor which is disposed in the vehicle body ahead of the position where the first sensor is disposed, and which outputs a signal corresponding to an impact applied to the vehicle, and a shutoff which receives an output signal of the second sensor, respectively; Two filters having different frequencies from each other; threshold changing means for changing the predetermined threshold according to a signal passing through the filter having a higher cutoff frequency among signals passing through the two filters; Bad road discriminating means for discriminating whether or not the vehicle is traveling on a bad road, based on a signal having passed through the filters having a lower cutoff frequency among the signals passing through the two filters, When it is determined that the vehicle is traveling on a rough road, a change prohibition that prohibits a change of the predetermined threshold value in accordance with a signal that has passed the filter having a high cutoff frequency by the threshold value change unit is prohibited. It is achieved by the activation control apparatus of an airbag apparatus characterized by comprising: a means.

[0010] In the invention according to claim 2, the second sensor outputs a signal corresponding to an impact applied to the vehicle. Second
Are output to two filters having different cutoff frequencies. Amplitude characteristics and phase characteristics are different between signals passing through the two filters. In the present invention, the predetermined threshold value for starting the airbag device is changed according to a signal that has passed through a filter having a high cutoff frequency. Also, whether or not the vehicle runs on a bad road is accurately determined based on a signal that has passed through a filter having a low cutoff frequency. If it is determined that the vehicle is traveling on a rough road, the predetermined threshold value,
A change in accordance with a signal passed through a filter having a high cutoff frequency is prohibited. Therefore, according to the present invention, it is possible to prevent the airbag device from being easily activated even when a large impact is applied to the front portion of the vehicle body when traveling on a rough road.

Further, the above object is achieved by a first sensor which is disposed at a predetermined position in a vehicle body and outputs a signal according to an impact applied to the vehicle, and the first sensor. Activation control means for activating the airbag device when a parameter based on the output signal of the output signal exceeds a predetermined threshold value.
A second sensor that is disposed in front of the first sensor in the vehicle body and outputs two signals corresponding to impacts applied to vehicles having different smoothnesses;
Threshold value changing means for changing the predetermined threshold value in accordance with a signal having a low smoothness among the signals output from the second sensor; and a smoothness level among the signals output from the second sensor. A bad road discriminating means for discriminating whether or not the vehicle is traveling on a rough road based on the high signal of the vehicle; and This is achieved by an activation control device for an airbag device, comprising: a change prohibition unit that prohibits a change of the predetermined threshold value in response to a signal with low smoothness by a threshold value change unit.

According to the third aspect of the invention, the second sensor outputs two signals corresponding to impacts applied to vehicles having different smoothness. A signal with low smoothness is
7 shows a waveform that is closer to the original waveform of the impact applied to the vehicle than a signal having a high degree of smoothness. Therefore, the predetermined threshold value is changed according to a signal having a low degree of smoothness in order to accurately and appropriately determine whether the activation of the airbag device is appropriate. In addition, since a signal with a high degree of smoothness is output as a signal that attenuates a fluctuation component of an impact applied to a vehicle, a signal corresponding to the magnitude of the impact may appear as a signal with a high degree of smoothness at the time of a collision. When traveling on a road, only a signal that is attenuated more than a signal corresponding to an actual impact can appear. Therefore, whether or not the vehicle travels on a rough road is determined based on a signal with high smoothness. If it is determined that the vehicle is traveling on a bad road,
The change of the predetermined threshold value according to the signal with low smoothness is prohibited. Therefore, according to the present invention, it is possible to prevent the airbag device from being easily activated even when a large impact is applied to the front portion of the vehicle body when traveling on a rough road.

In this case, as set forth in claim 4, in the activation control device for an airbag apparatus according to any one of claims 1 to 3, the threshold value changing means is configured to control the vehicle by the bad road determination means. If it is determined that the vehicle is traveling on a rough road, the predetermined threshold value may be changed to a predetermined value.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a system configuration diagram of an airbag device activation control device according to an embodiment of the present invention. The system according to the present embodiment includes an electronic control unit (hereinafter, referred to as an ECU) 12 mounted on a vehicle 10, and is controlled by the ECU 12.

The system of this embodiment includes a floor sensor 14 disposed near a floor tunnel in the center of the vehicle body, and
Satellite sensors 16 and 18 are provided on left and right side members at the front of the vehicle. The floor sensor 14
This is an electronic deceleration sensor that outputs a signal corresponding to the magnitude of an impact acting in the vehicle front-rear direction (that is, deceleration in the vehicle front-rear direction) at the center of the vehicle body.

Each of the satellite sensors 16 and 18 has two low-pass infinite impulse responses (Ifinite impulse responses; I) having different cutoff frequencies.
IR) filter. These IIR filters have, for example, cutoff frequencies of 40 Hz and 20 Hz, and both are constituted by predetermined Kalman filters. Each of the satellite sensors 16 and 18 converts the two signals (hereinafter referred to as the two signals) by two IIR filters separately converting the shock acting in the front-rear direction of the vehicle body into two deceleration waveforms having different smoothness. , An electronic deceleration sensor that outputs the respective signals. Hereinafter, a deceleration signal output through an IIR filter with a high cutoff frequency is referred to as a “first deceleration signal”, and a deceleration signal output through an IIR filter with a low cutoff frequency is referred to as a “second deceleration signal”. Respectively.

Each of the floor sensor 14 and the satellite sensors 16 and 18 has a self-diagnosis function, and a signal (hereinafter, referred to as a normal state) indicating whether the self-function is normal or a self-failure has occurred.・ It is called a failure determination signal.)
Is output to the outside together with the deceleration signal at predetermined intervals.

The ECU 12 includes an input / output circuit 20, a central processing unit (hereinafter, referred to as a CPU) 22, a read-only memory (hereinafter, referred to as a ROM) 24 in which processing programs and tables necessary for computation are stored in advance. , A random access memory (RA) used as a work area
M) 26 and a bidirectional bus 28 connecting these elements.

FIG. 2 is a diagram showing a connection state between the ECU 12 and the satellite sensors 16 and 18 in this embodiment. As shown in FIG. 1, the floor sensor 14 and the satellite sensors 16 and 18 are connected to an input / output circuit 20 of the ECU 12. An output signal of the floor sensor 14,
The output signals of the satellite sensors 16 and 18 are supplied to the input / output circuit 20 and stored in the RAM as appropriate according to the instruction of the CPU 22. As shown in FIG. 2, the two deceleration signals output by the satellite sensor 16 are supplied to the ECU 12, and the two deceleration signals output by the satellite sensor 18 are also output from the ECU 12 respectively.
Supplied to

The ECU 12 determines the magnitude of the deceleration Gf acting on the central portion of the vehicle body based on the output signal of the floor sensor 14.
Is detected. In addition, the ECU 12 controls the satellite sensor 1
Based on the first deceleration signal output from the vehicle 6, the deceleration G _{SL1 having} relatively low smoothness as a deceleration acting on the front left portion of the vehicle body.
Is detected, and based on the second deceleration signal output by the satellite sensor 16, the deceleration G having a relatively high smoothness is determined.
Detect _SL2 . Further, based on the first deceleration signal output by the satellite sensor 18, the deceleration G _SR1 having relatively low smoothness is detected as the deceleration acting on the front right portion of the vehicle body, and the second deceleration output by the satellite sensor 18 is detected. Based on the speed signal, a deceleration G _SR2 having relatively high smoothness is detected. When the waveform of the deceleration G _SL1 is compared with the waveform of G _{SL2, or when} the waveform of the deceleration G _SR1 is compared with the waveform of G _SR2 , the deceleration G _{SL1 having} relatively low smoothness is obtained. , G
_SR1 shows a value that is closer to the deceleration actually acting on each part of the vehicle. Further, the ECU 12 determines whether or not each sensor has a failure based on a normal / failure determination signal corresponding to a self-diagnosis result output from each sensor.

The system of this embodiment further includes an airbag device 30 which is mounted on the vehicle 10 and operates so as to protect occupants. The airbag device 30 has a drive circuit 32, an inflator 34, and an airbag 36. The inflator 34 has a built-in ignition device 38 connected to the drive circuit 32 and a gas generating agent (not shown) that generates a large amount of gas by the heat generated by the ignition device 38.
The airbag 36 is inflated and deployed by the generation of gas. The airbag 36 is provided at a position interposed between an occupant of the vehicle 10 and a vehicle-mounted component when inflated and deployed.

The drive circuit 32 of the airbag device 30
It is connected to the input / output circuit 20 of the CU 12. The airbag device 30 is activated when a drive signal is supplied from the input / output circuit 20 to the drive circuit 32, and deploys the airbag 36. The CPU 22 of the ECU 12 includes an activation control unit 40 and a threshold value setting unit 42. The activation control unit 40 of the CPU 22 calculates a predetermined parameter based on the deceleration Gf detected using the output signal of the floor sensor 14 according to a processing program stored in the ROM 24, as described later, and calculates the calculated parameter. It is determined whether or not the parameter exceeds a predetermined threshold value SH.
The supply of the drive signal to the drive circuit 32 of 0 is controlled. Further, the threshold value setting unit 42 is provided for the satellite sensors 16, 1
Based on the decelerations G _SL1 and G _SR1 with low smoothness detected based on the first deceleration signal of No. 8, the predetermined threshold SH used in the activation control unit 40 is appropriately set.

Next, the contents of the processing performed by the CPU 22 of this embodiment will be described.

In the present embodiment, the start control unit 40 performs a predetermined calculation on the deceleration Gf detected based on the output signal of the floor sensor 14 to calculate the calculated value f (Gf) and the speed V.
Find n. Specifically, the speed Vn is a value obtained by time-integrating the deceleration Gf. That is, the traveling vehicle 1
When the deceleration Gf is added to 0, the object (for example, the occupant) in the vehicle accelerates forward with respect to the vehicle 10 due to the inertial force.
Can be obtained by integrating the deceleration Gf with time. The calculated value f (Gf) may be the deceleration Gf itself or a value obtained by time-integrating the deceleration Gf with respect to a unit time. FIG. 3 is a diagram in which the relationship between the calculated value f (Gf) and the speed Vn under a predetermined situation is plotted at regular intervals. Activation control unit 4
0 is obtained after calculating the calculated value f (Gf) and the speed Vn.
As shown in (2), the value determined from the relationship between the two is compared in magnitude with the threshold value SH as a determination map set by the threshold value setting unit 42.

FIG. 4 shows the operation value f (G
FIG. 6 is a diagram showing a change pattern of a threshold value SH (hereinafter, referred to as a threshold value change pattern) functioning as a determination map for a relationship between f) and the speed Vn. Note that FIG. 4 shows five patterns of a threshold change pattern: a Hi map, a Lo3 map, a Lo2 map, a Lo1 map, and a fail-safe map. In this embodiment, the Hi map is a reference map in advance, and the fail-safe map partially overlaps with the Lo3 map. FIG. 5 is a diagram for explaining a method of setting a threshold change pattern in the present embodiment.

In this embodiment, the threshold value setting section 42
Is a calculated value f determined experimentally in advance as shown in FIG.
A threshold change pattern regarding the relationship between (Gf) and the speed Vn is stored. These threshold change patterns require the airbag device 30 to be activated when an impact is applied to the vehicle 10 based on the decelerations G _SL1 and G _SR1 based on the first deceleration signals of the satellite sensors 16 and 18. It is set at the boundary between when there is and when it is not necessary.

That is, the greater the impact applied to the front of the vehicle body, the higher the possibility that the vehicle 10 has collided.
It is appropriate to switch the threshold change pattern so that the airbag device 30 is easily activated. Therefore, in the present embodiment, the threshold value setting section 42 sets the threshold value SH to decrease as the decelerations G _SL1 and G _SR1 detected based on the first deceleration signals of the satellite sensors 16 and 18 increase. Then, a threshold change pattern is selected and set. Specifically, as shown in FIG. 5, the decelerations G _SL1 , G _SR1
Is smaller than the first predetermined value G _S1 , the Hi map is selected as the threshold change pattern, and if it is not less than the first predetermined value G _S1 and less than the second predetermined value G _S2 , the Lo3 map is selected. and, if it the second predetermined value G _S2 or less than the third predetermined value G _S3 selects the Lo2 map, and if it is the third predetermined value G _S3 or selects the Lo1 map. Also,
If a failure occurs in the satellite sensors 16, 18 or a communication error occurs between the satellite sensors 16, 18 and the ECU 12, a fail-safe map is selected.

In the above configuration, the activation control unit 40
As a result of comparing a value determined from the relationship between the calculated value f (Gf) and the speed Vn with the threshold value SH of the threshold change pattern selected and set by the threshold value setting unit 42, the calculated value f
When the value determined from the relationship between (Gf) and the speed Vn exceeds the threshold SH, a drive signal is supplied from the input / output circuit 20 to the drive circuit 32 of the airbag device 30. In this case, the airbag 36 is deployed by activating the airbag device 30.

Therefore, according to the present embodiment, the threshold value for activating the airbag device 30 is changed in accordance with the impact applied to the front of the vehicle body. The bag device 30 is easily activated. Therefore, it is possible to appropriately start the airbag device 30 in accordance with a collision mode of the vehicle 10 such as a head-on collision, an offset collision, and an oblique collision.

Incidentally, the vehicle 10 may be subject to a large impact when traveling on a rough road, as in the case of a collision. Under the situation where the large decelerations G _SL1 , G _SR1 are detected based on the first deceleration signals of the satellite sensors 16, 18 when such a situation occurs, the threshold is temporarily set according to the decelerations G _SL1 , G _SR1. Assuming that a threshold change pattern with a small value SH is selected and set, the airbag 36 is easily deployed even though the vehicle 10 does not collide. In this regard, it is not appropriate to lower the threshold value SH in accordance with the decelerations G _SL1 and G _SR1 during running on a rough road in order to properly start the airbag device 30.

Therefore, the system of this embodiment is designed to
Accurately determines whether or not the vehicle 10 travels on a rough road, and prohibits the selection and setting of the threshold change pattern based on the magnitude of the decelerations G _SL1 and G _SR1 when the vehicle 10 travels on a rough road. By doing so, it is possible to prevent the airbag device 30 from being easily activated when traveling on a rough road. Hereinafter, the characteristic portion of the present embodiment will be described with reference to FIGS.

FIG. 6 shows the time change of the deceleration actually acting on the front part of the vehicle body when the vehicle 10 collides (FIG. 6A), based on the first deceleration signals of the satellite sensors 16 and 18. The detected deceleration G _SL1 with low smoothness,
The time change of G _SR1 (FIG. (B)) and the time change of high smoothness decelerations G _SL2 and G _SR2 detected based on the second deceleration signals of the satellite sensors 16 and 18 (FIG. C)) are shown respectively. FIG. 7 shows the time change of the deceleration actually acting on the front of the vehicle body when the vehicle 10 travels on a rough road (FIG. 7A).
6, temporal changes in the decelerations G _SL1 and G _SR1 with low smoothness detected based on the first and second deceleration signals (FIG. 6B);
And decelerations G _SL2 , G _{SR2 with} high smoothness detected based on the second deceleration signals of the satellite sensors 16, 18.
(C) of FIG. FIG.
7 and FIG. 7, the decelerations G _SL1 and G _SR1 are changed to the deceleration G _{S * 1}
And the decelerations G _SL2 and G _SR2 are represented as deceleration G _{S * 2} , respectively.

The form of impact applied to the vehicle 10 differs between the case where the vehicle 10 collides and the case where the vehicle 10 runs on a bad road. That is, as shown in FIGS. 6 (A) and 7 (A), a large deceleration is maintained for a long time due to the impact continuing for a relatively long time at the time of a collision, while the impact is long at the time of traveling on a rough road. The deceleration does not continue over the period, but repeatedly increases and decreases in a short cycle.

At this time, the deceleration G _{S * 1} based on the first deceleration signal output from the satellite sensors 16 and 18 (that is, the deceleration with low smoothness) is determined in either case of collision or running on a rough road. Also, as shown in FIGS. 6B and 7B, a value close to the deceleration due to the impact actually applied to the front of the vehicle body (the deceleration shown in FIGS. 6A and 7A) Becomes Therefore, according to the deceleration _{GS * 1} based on the first deceleration signal, the magnitude of the impact applied to the front portion of the vehicle body can be grasped relatively accurately. As described above, when the impact applied to the front of the vehicle body is large, it is appropriate to switch the threshold change pattern so that the airbag device 30 is easily activated. Therefore, the satellite sensor 16,
If the threshold change pattern is changed in accordance with the first deceleration signal output by the motor 18, the airbag device 30 can be started properly.

Further, the deceleration G _{S * 2} based on the second deceleration signal output from the satellite sensors 16 and 18 (ie,
The waveform of (deceleration with high smoothness) is shown in FIG.
As shown in (C), the deceleration G based on the first deceleration signal
The waveform has poor response compared to the waveform of _{S * 1} . However, at the time of collision, large deceleration is maintained for a long time,
As shown in FIG. 6C, the deceleration G _{S * 2} shows a larger value as time passes. On the other hand, when the vehicle is traveling on a rough road, the waveform of the deceleration GS _{* 2} has a poorer response than the waveform of the deceleration GS _{* 1} , as shown in FIG. Since a large deceleration does not continue for a long period of time, the fluctuation component of the deceleration _{GS * 2} is attenuated by the IIR filter having a low cutoff frequency. Therefore, when traveling on a rough road, the deceleration G _{S * 2} is
As shown in (C), the value shows a value greatly attenuated compared to the actual deceleration, and does not show a very large value.

Therefore, if it is determined whether or not the deceleration _{GS * 2} based on the second deceleration signals output by the satellite sensors 16 and 18 exceeds a predetermined value, the vehicle 10 travels on a rough road. It is possible to distinguish whether the vehicle 10 has collided or the vehicle 10 has collided. Therefore, the system according to the present embodiment uses the second sensor output from the satellite sensors 16 and 18.
Based on the deceleration signal, it is determined whether or not the vehicle 10 runs on a bad road.

The system according to the present embodiment is adapted to the vehicle 10
If it is determined that the vehicle is traveling on a rough road, it is prohibited to change the threshold change pattern in accordance with the first deceleration signals output from the satellite sensors 16 and 18, and the reference is made based on the threshold change pattern. Is maintained in the Hi map. According to such a configuration, a map having a low threshold SH is not selected and set as the threshold change pattern when traveling on a rough road, so that it is possible to avoid a situation in which the airbag device 30 is easily activated. It becomes possible.

FIG. 8 is a flowchart showing an example of a control routine executed by the ECU 12 in this embodiment to realize the above-described functions. The routine shown in FIG. 8 is a routine that is repeatedly started at predetermined time intervals. When the routine shown in FIG. 8 is started, first, the process of step 100 is executed.

In step 100, the satellite sensor 1
High smoothness are detected based on the second deceleration signal 6,18 deceleration G _{S * 2} whether exceeds a predetermined value G _SH is determined. Note that the predetermined value G _SH is the maximum value expected to appear as a highly smooth deceleration G _{S * 2} of the second deceleration signal output by the satellite sensors 16 and 18 when the vehicle 10 travels on a rough road. This value is set in advance to a constant value.

As a result, when G _{S * 2} > G _SH is satisfied, it can be determined that the state in which the impact acting on the vehicle 10 is large has continued for a relatively long time. In this case, the vehicle 10 is not traveling on a rough road, and it can be determined that the vehicle 10 is subjected to an impact due to a collision.
It is appropriate to change the threshold change pattern for starting 0 according to the deceleration _{GS * 1} having low smoothness. Therefore, if it is determined that G _{S * 2} > G _SH holds, the process of step 102 is executed next.

On the other hand, if G _{S * 2} > G _SH does not hold,
Even when a large impact acts on the front part of the vehicle body of the vehicle 10, it can be determined that the state has not been continued for a long time. In this case, it can be determined that the impact due to the collision has not been applied to the vehicle 10, and the threshold change pattern for activating the airbag device 30 is changed to the deceleration _{GS * 1} with low smoothness.
It can be determined that there is no need to change according to. Therefore, G
If it is determined that _{S * 2} > G _SH does not hold, the process of step 104 is executed next.

In step 102, a map is selected and set as a threshold change pattern in accordance with the low-smoothness deceleration G _{S * 1} detected based on the first deceleration signals of the satellite sensors 16 and 18. The processing is executed. After the process of step 102 is executed, the deceleration G _{S * 1}
Is compared with a value determined from the relationship between the calculated value f (Gf) and the speed Vn to determine whether the activation of the airbag device 30 is appropriate. You. When the process of step 102 is completed, the current routine is completed.

In step 104, a process for selecting and setting a Hi map as a threshold change pattern is executed. After the process of step 104 is performed, H
By comparing the threshold value SH on the i-map with a value determined from the relationship between the calculated value f (Gf) and the speed Vn, it is determined whether or not the activation of the airbag device 30 is appropriate. When the process of step 104 is completed, the current routine is completed.

According to the above processing, the satellite sensor 1
When the deceleration GS _{* 2} having high smoothness detected based on the second and sixth deceleration signals exceeds a predetermined value, the threshold change pattern for activating the airbag device 30 is used. A map corresponding to the low-smoothness deceleration _{GS * 1} detected based on the first deceleration signals of the satellite sensors 16 and 18 is selected and set, and the high-smoothness deceleration _{GS * 2} is determined. If the value does not exceed the threshold value, the threshold change pattern is H
i-map can be selected and set.

If the deceleration _{GS * 2} with high smoothness based on the second deceleration signal output from the satellite sensors 16 and 18 through the IIR filter having a low cutoff frequency exceeds a predetermined value, the vehicle 10 is turned on a rough road. , And it can be determined that an impact due to the collision is applied to the front portion of the vehicle body of the vehicle 10. On the other hand, if the deceleration _{GS * 2} with high smoothness does not exceed the predetermined value, the vehicle 10 may be traveling on a rough road, and a large impact due to the collision is not applied to the vehicle 10. I can judge. That is, in the present embodiment, the threshold change pattern for activating the airbag device 30 depends on the magnitude of the impact applied to the front of the vehicle body when a large impact caused by the collision is applied to the vehicle 10. On the other hand, when a large impact due to running on a rough road is applied, the Hi map is maintained regardless of the magnitude of the impact applied to the front part of the vehicle body.

For this reason, in the present embodiment, the Lo map having a low threshold SH is selected and selected as the threshold change pattern for starting the airbag device 30 when traveling on a rough road.
Setting is avoided. Therefore, according to the activation control device for the airbag device 30 of the present embodiment, it is possible to avoid a situation in which the airbag device is easily activated even when the impact applied to the front portion of the vehicle body is large when traveling on a rough road. As a result, the determination for activating the airbag device 30 can be properly performed while distinguishing between traveling on a rough road and collision.

In the above embodiment, the floor sensor 14 is the "first sensor" described in the claims.
The calculated value f obtained by performing a predetermined calculation on the deceleration Gf detected based on the output signal of the floor sensor 14
(Gf) and the speed Vn are defined as "parameters" described in the claims, and the threshold value SH on the threshold change pattern is defined as a "predetermined threshold value" described in the claims.
The IIR filters included in the satellite sensors 16 and 18 correspond to a “filter” described in the claims, and the satellite sensors 16 and 18 correspond to a “second sensor” described in the claims. ing.

In the above embodiment, the ECU 1
2 is a calculated value f based on the output signal of the floor sensor 14.
The value determined from the relationship between (Gf) and the speed Vn is the threshold value SH.
In the case where the value exceeds the threshold value, the drive signal is supplied from the input / output circuit 20 to the drive circuit 32 of the airbag device 30 so that the “activation control means” described in the claims can execute the processing of the above steps 102 and 104. By executing, the "threshold changing means" described in the claims,
By executing the process of step 100, the "bad road discriminating means" described in the claims becomes negative in step 102 if the determination in step 100 is negative.
By executing the processing of step 104 in place of the above, "change prohibition means" described in the claims are realized.

In the above embodiment, the satellite sensors 16 and 18 have two IIRs having different characteristics.
A filter that outputs two deceleration signals (ie, first and second deceleration signals) having different smoothness corresponding to the impact acting on the front of the vehicle body, and the ECU 12 outputs the deceleration signals to the deceleration signals. Although it is determined whether or not the vehicle travels on a bad road based on the determination, it is determined whether or not the activation of the airbag device 30 is appropriate. However, the present invention is not limited to this, and the satellite sensors 16 and 18 may include filters. However, the ECU 12 only outputs one deceleration signal corresponding to an impact acting on the front of the vehicle body, and the ECU 12 incorporates two filters having different characteristics.
The two decelerations having different smoothness levels are respectively detected based on the deceleration signals output by the control units 6 and 18, and the presence or absence of traveling on a bad road is determined based on the detected deceleration. May be determined. In this case, the satellite sensors 16 and 18 are provided in the second aspect.
The filter incorporated in the ECU 12 in the “second sensor” described above corresponds to the “filter” in claim 2.

As described above, claims 1, 2, 3, and 4
According to the configuration described above, in the configuration in which the predetermined threshold value for activating the airbag is changed according to the magnitude of the impact applied to the front portion of the vehicle body, when the vehicle travels on a rough road, It is possible to prevent the airbag device from being easily activated even if the size is large.

[Brief description of the drawings]

FIG. 1 is a system configuration diagram of an activation control device of an airbag device according to an embodiment of the present invention.

FIG. 2 is a diagram illustrating a connection state between an ECU and a satellite sensor according to the embodiment.

FIG. 3 shows a velocity Vn and a calculated value f (Gf) under a predetermined condition.
FIG. 6 is a diagram in which the relationship with is plotted at regular intervals.

FIG. 4 is a diagram illustrating a calculated value f (Gf) and a speed Vn according to the embodiment.
FIG. 9 is a diagram showing a change pattern of a threshold value SH functioning as a determination map for a relationship with the threshold value SH.

FIG. 5 is a diagram for explaining a method of setting a change pattern of a threshold value SH in the present embodiment.

FIG. 6 is a diagram for explaining a time change of deceleration acting on the vehicle body when the vehicle collides;

FIG. 7 is a diagram for explaining a time change of a deceleration acting on the vehicle body when the vehicle travels on a rough road.

FIG. 8 is a flowchart of an example of a control routine executed in the embodiment.

[Explanation of symbols]

 12 electronic control unit (ECU) 14 floor sensor (first sensor) 16, 18 satellite sensor (second sensor) 30 airbag device 40 activation control unit (activation control means) 42 threshold value setting unit (threshold value) Setting means)

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Yujiro Miyata 1 Toyota Town, Toyota City, Aichi Prefecture Inside Toyota Motor Co., Ltd. (72) Inventor Kibumi No. 1 Toyota Town, Toyota City, Aichi Prefecture Toyota Motor Corporation F Terms (reference) 3D054 AA12 EE06 EE14 EE25 FF16

Claims (4)

[Claims] A first sensor disposed at a predetermined position in the vehicle body for outputting a signal corresponding to an impact applied to the vehicle; and a parameter based on an output signal of the first sensor is set to a predetermined threshold value. An activation control device for activating the airbag device when the air pressure exceeds the threshold, wherein the activation control device for the airbag device includes: And a second sensor that outputs a signal corresponding to each of the signals through two filters having different cutoff frequencies, and a signal output through the filter having a higher cutoff frequency among the signals output by the second sensor. Threshold value changing means for changing the predetermined threshold value according to the following: a signal output through the filter having a lower cutoff frequency among signals output by the second sensor. A bad road discriminating means for discriminating whether or not the vehicle is traveling on a rough road, and the threshold value when the bad road discriminating means determines that the vehicle is traveling on a bad road. An activation control device for an airbag device, comprising: a change prohibition unit that prohibits a change of the predetermined threshold value according to a signal output through the filter having a high cutoff frequency by a change unit. 2. A first sensor which is disposed at a predetermined position in a vehicle body and outputs a signal corresponding to an impact applied to the vehicle, and a parameter based on an output signal of the first sensor sets a predetermined threshold value. An activation control device for activating the airbag device when the air pressure exceeds the threshold, wherein the activation control device for the airbag device includes: A second sensor that outputs a signal according to the following: two filters each having a different cut-off frequency to which an output signal of the second sensor is input; and a filter having a higher cut-off frequency among the signals that have passed through the two filters. Threshold changing means for changing the predetermined threshold according to a signal passed through the filter; and a filter having a lower cut-off frequency among the signals passed through the two filters. A bad road discriminating means for discriminating whether or not the vehicle is traveling on a bad road based on the passed signal; and An activation control device for an airbag device, comprising: a change prohibition unit that prohibits a threshold value changing unit from changing the predetermined threshold value according to a signal that has passed through the filter having a high cutoff frequency. 3. A first sensor which is disposed at a predetermined position in a vehicle body and outputs a signal corresponding to an impact applied to the vehicle, and a parameter based on an output signal of the first sensor sets a predetermined threshold value. Activation control means for activating the airbag device when the air pressure exceeds the threshold, wherein the activation control device for the airbag device includes: a first sensor disposed in the vehicle body in front of a position where the first sensor is disposed; A second sensor that outputs two signals corresponding to impacts applied to different vehicles, and the predetermined threshold value is changed according to a signal having a low degree of smoothness among the signals output by the second sensor. Threshold value changing means; bad road determining means for determining whether or not the vehicle is traveling on a rough road, based on a signal having a high degree of smoothness among signals output by the second sensor; Road discriminating means A change prohibition unit for prohibiting a change of the predetermined threshold value in accordance with a signal having a low smoothness by the threshold value change unit when it is determined that the vehicle is traveling on a rough road. An activation control device for an airbag device, characterized in that: 4. The activation control device for an airbag device according to claim 1, wherein the threshold value changing unit determines that the vehicle is traveling on a rough road by the rough road determination unit. If it is determined, the predetermined threshold value is changed to a predetermined value.