JP2001050972A - Soft crash detection method and soft crash detection device - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To provide a method and an apparatus for detecting a soft crash better than before. SOLUTION: When a soft crash occurs, the vehicle body deceleration increases and then decreases, then increases again to increase the first and second maximum values, the first and second maximum values.
A local minimum occurs, with the first maximum being less than the second maximum. The first maximum value of the vehicle body central portion longitudinal deceleration based on the detected value of the floor sensor based on the detection value of the floor sensor, the average value of the deceleration until the first maximum value is obtained, and the first maximum value until the first maximum value is obtained. The deceleration average value until the minimum value is obtained is obtained, the left / right deceleration ratio is obtained based on the front / rear deceleration of the left and right front portions based on the detection values of the left and right front sensors, and the first maximum value is set to the first setting. If the deceleration is larger than the second set deceleration, the left / right deceleration ratio is larger than the set ratio, and if the ratio of the average of the deceleration before and after the maximum value is smaller than the set value, it is determined that a soft crash has occurred and the ignition is determined. A threshold value and an airbag operation mode are set, and when the deceleration exceeds the ignition determination threshold value, the airbag is inflated at a high speed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for detecting a soft crash, and more particularly to a method for detecting a soft crash.

[0002]

2. Description of the Related Art A soft crash is a collision which is defined on the basis of a change in the longitudinal deceleration of a vehicle body due to a collision (a deceleration from which noise has been removed, and is hereinafter simply referred to as a deceleration unless otherwise required). It is a kind. In the case of a soft crash, the deceleration increases once, then decreases and then increases again, resulting in two maximum values and one minimum value, and 1
The maximum value of the deceleration caused by the second increase is larger than the maximum value of the deceleration caused by the second increase. A pole collision is an example of a soft crash. Pole collision
This is a collision in which the center of the vehicle in the width direction hits a pole, which is a strong collision target such as a telephone pole.First, the bumper collides with the pole, and then the elastic and plastic deformation of the members behind the bumper occurs. The body moves forward and the engine collides and stops. The deceleration increases when the bumper collides with the pole, then the deceleration decreases due to the deformation of the front part of the vehicle body, increases again due to the collision with the engine, and decreases, but the engine is stronger than the bumper, The deceleration caused by the collision of the engine is larger. Other examples of the soft crash include a form in which the collision target falls down in the traveling direction of the vehicle after the collision of the vehicle, and a form in which the vehicle falls under the collision object. The case shows a similar change. For it,
In the case of a head-on collision, only one increase or decrease in deceleration occurs.
A head-on collision is a collision in which the left and right side frames of the vehicle collide with the collision target at the same time.However, since the side frames are hard, the vehicle stops due to the collision between the side frame and the collision target, and a large deceleration occurs in a short time. Occurs once.

[0003] As described above, there are various types of vehicle collisions. Therefore, when an occupant protection device such as an airbag device is operated based on a vehicle collision, the occupant protection device is operated in a mode corresponding to the type of collision. It is desirable. Therefore, for example, in the occupant protection device described in Japanese Patent Application Laid-Open No. H10-152014, a floor sensor is provided at the center of the vehicle, and satellite sensors are provided at the left and right of the front part of the vehicle, respectively. And the satellite sensor detects the occurrence of an impact equal to or greater than the reference value, and determines the type of collision, and operates the occupant protection device at different decelerations according to the type of collision. With this configuration, the occupant protection device can be appropriately operated at the time of various types of collisions.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to provide a method and apparatus for detecting a soft crash more favorably than before. In addition, according to the present invention, the following soft crash detection methods and apparatuses can be obtained. As in the case of the claims, each aspect is divided into sections, each section is numbered, and if necessary, the other sections are cited in a form in which the numbers are cited. This is for the purpose of facilitating the understanding of the present invention and should not be construed as limiting the technical features and combinations thereof described in the present specification to those described in the following sections. . Further, when a plurality of items are described in one section, it is not always necessary to adopt the plurality of items together, and it is also possible to take out and adopt only some of the items. (1) At least the first maximum value of the front-rear deceleration at the center of the vehicle body based on the detection value of the main sensor disposed near the driver's seat of the vehicle body is larger than the first set deceleration, A first condition that it is smaller than a second set deceleration;
The average value from the first maximum value to the first minimum value, which is the first minimum value, is divided by the average value of the deceleration in the front-rear direction of the vehicle body center portion based on the detection of the main sensor, up to the first maximum value. The second condition that the maximum value front-rear ratio is smaller than the first set ratio, and the front-rear deceleration of the left and right front portions based on the detection values of the sub-sensors respectively disposed at the left and right front portions of the vehicle body. The third ratio is that the left-right ratio obtained by dividing the longitudinal deceleration by the greater longitudinal deceleration is larger than the second set ratio.
A soft crash detection method that determines that a soft crash has occurred when all three conditions are satisfied (claim 1). Each of the main sensor and the sub-sensor may be a sensor that outputs the detected deceleration as it is, or may be a sensor that outputs the deceleration at a plurality of levels. If a soft crash occurs, as described above, the deceleration is increased and decreased twice, so that two maximum values and one minimum value are obtained, and the first maximum value generated first is the second maximum value generated next. Less than the maximum value. Further, a soft crash is a symmetrical collision, that is, a collision in which impacts generated on the left and right sides of the vehicle are substantially the same. Each of the first to third conditions is set to detect a soft crash based on these characteristics. The first set deceleration in the first condition is an operation device that operates based on the detection of a soft crash, for example, whether an impact applied to the airbag device to inflate the airbag is applied to the vehicle body. If it is a size that can be determined and it is the first maximum value of the deceleration due to the soft crash, the value is set to a value exceeding the value, and the second set deceleration is set to a value that can eliminate a head-on collision. You. As described above, a large deceleration occurs only once in a short time during a head-on collision, but since the side frame is harder than the bumper, the maximum value of deceleration due to head-on collision is the first maximum value of deceleration due to soft crash. Greater than. Therefore, the second set deceleration is set to a value that does not exceed the first maximum value of the deceleration due to the soft crash and exceeds the first deceleration due to the soft crash, thereby eliminating the frontal collision. The second condition is that, in the case of a soft crash, the deceleration is based on the fact that the first maximum value is generated, the deceleration again changes from decreasing to increasing, and the first minimum value is generated at a time after the first maximum value. Is set. The first maximum is
Although it occurs in a short time due to the collision between the collision target and the bumper,
Due to the collision with the engine, there is time to increase again, and a relatively small deceleration continues until the first minimum value is reached. Therefore, when the deceleration to the first maximum value and the deceleration from the first maximum value to the first minimum value are respectively averaged and compared, the latter average value is often smaller than the former average value. Depending on the vehicle, the latter is not necessarily larger, but the ratio between the two is almost determined by the vehicle. On the other hand, in the case of a head-on collision, the vehicle stops due to the collision between the collision object and the side frame, and the deceleration decreases in a short time. Therefore, the average of the deceleration from the first maximum value to the first minimum value is obtained. The value is a large value that does not occur at the time of soft crash with respect to the average value of the deceleration up to the first maximum value.
Further, when the road surface is a rough road, the deceleration generally increases and decreases continuously, so that the ratio before and after the maximum value becomes a large value even when the maximum value and the minimum value occur. Therefore, the first
In view of this situation, the setting ratio is set to a size that allows the soft crash to be distinguished from other collisions and impacts based on the ratio before and after the maximum value. It is particularly desirable to set according to the type of vehicle. The third condition is set based on the feature that the soft crash is a symmetrical collision. The decelerations generated on both the left and right sides of the vehicle body due to the soft crash are substantially equal. Therefore, as the left-right ratio is closer to 1, the left-right symmetry is higher, and the second set ratio is smaller than 1, but set to a value close to 1. Each longitudinal deceleration of the left and right front portions of the vehicle body for obtaining the left / right ratio may be, for example, a detection value of a sub sensor obtained when comparing the left / right ratio with the second set ratio, and may be detected until this comparison is performed. Alternatively, an integrated value of all detected values or an average value may be used. If all of the first to third conditions are satisfied, all the features of the soft crash are provided, and it can be determined that the soft crash has occurred. (2) The longitudinal deceleration of the vehicle body center part based on the detection value of the main sensor and the longitudinal deceleration of the vehicle front left and right part based on the detection value of the sub-sensor respectively smooth the output of the main sensor and the sub-sensor. The soft crash detection method according to the above mode (1).
The output of the main sensor and the sub sensor may be smoothed by smoothing the output signal of the main sensor and the sub sensor by a smoothing circuit such as a filter circuit. Smoothing may be performed by filter means or gradient limiting means. If the values detected by the main sensor and the sub-sensor are each a value that does not include noise, it is not essential to provide a smoothing unit, but often includes noise. Therefore, if the output of the sensor is smoothed by the smoothing means, noise is reduced, and the occurrence of soft crash is more accurately detected. (3) Vehicle center deceleration obtaining means for obtaining the front-rear deceleration of the vehicle body central part in which the output of the main sensor disposed near the driver's seat of the vehicle body is smoothed, and vehicle body central part deceleration obtaining means First maximum value acquisition means for acquiring a first maximum value which is the first maximum value of the longitudinal deceleration of the vehicle body central part acquired by the first and second vehicle deceleration acquisition means. The deceleration for obtaining the average value of the longitudinal deceleration up to the first maximum value and the average value from the first maximum value to the first minimum value of the longitudinal deceleration at the center of the vehicle body, which is the first minimum value. Speed average value obtaining means, and left and right front deceleration obtaining means for obtaining the front-rear deceleration of the left and right front parts of the vehicle body in which the outputs of the sub-sensors disposed on the left and right front parts of the vehicle are smoothed, at least, The first maximum value is greater than the first set deceleration, The average value from the first maximum value to the first minimum value is divided by the average value of the first condition that is smaller than the second set deceleration and the average value of the deceleration in the front-rear direction of the vehicle body center portion up to the first maximum value. The second condition that the maximum value front-rear ratio is smaller than the first set ratio, and the smaller front-rear deceleration of the left-right front deceleration obtained by the left-right front deceleration obtaining means is set to A determination unit that determines that a soft crash has occurred when all three conditions, that is, a third condition that a left-right ratio divided by a larger longitudinal deceleration is greater than a second set ratio, are satisfied. Apparatus (Claim 2). The main sensor provided near the driver's seat of the vehicle body, the sub-sensors provided respectively on the left and right front portions of the vehicle body, and the main and sub-smoothing means for smoothing the outputs of these sensors respectively comprise a soft crash detection device. It may or may not be a component. In the latter case, the deceleration in the front-rear direction may be obtained from an apparatus including a main sensor, a sub sensor, a smoothing unit, and the like. According to this aspect, for example,
The functions and effects described in the items (1) and (2) are obtained. (4) The soft crash detection device according to (3), an airbag, an inflator capable of inflating the airbag at different speeds, and the airbag when the soft crash detection device detects a soft crash. An inflator control device for inflating the bag at a speed equal to or higher than the middle speed among the different speeds. The inflator may be one that can inflate the airbag at different speeds in multiple stages, or one that can inflate at a continuously changing speed. In the inflator which can inflate the airbag in two stages of high speed and low speed, the speed higher than the middle is high speed, and in the inflator which can inflate the airbag in three stages of high speed, medium speed and low speed,
Medium or high speed. However, in a soft crash, it is often desirable to inflate the airbag at the highest speed. The inflator may be provided with a plurality of airbags having the same speed at which the airbag is inflated, and among them, the number of inflators for inflating the airbag may be different at the same time, so that the airbag inflation speed may be different. A plurality of inflators having different inflation speeds may be provided and selectively used according to the required inflation speed. Alternatively, a single inflator may be used to change the inflation speed in multiple steps or steplessly. The airbag may be inflated at an appropriate speed. According to the soft crash detection device described in the item (3), the soft crash is not detected until the first minimum value occurs, and it takes a longer time to detect the soft crash than a head-on collision or the like. However, when a soft crash is detected, the occupant can be sufficiently protected because the airbag is inflated at a speed higher than the middle speed.

[0005]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings, taking detection of a soft crash in an airbag apparatus as an example. As shown in FIG. 1, an airbag device 10 as an occupant protection device according to the present embodiment has an electronic control unit 12 and an airbag 14 as a control device. The electronic control unit 12 includes a microcomputer 16 (hereinafter, simply referred to as a microcomputer 16) and two drive circuits 18. The microcomputer 16 includes a PU (processing unit) 20, a ROM 22, and a RAM 2
4, including a bus 26 connecting them and an I / O circuit 28 serving as an input / output circuit, on a floor tunnel which is a member constituting a vehicle body in a center portion of the vehicle 30 in the left-right direction, and near a driver's seat. It is provided in.

The microcomputer 16 receives, via an I / O circuit 28, detection signals of a floor sensor 32 as a main sensor and front sensors 34 and 36 as two sub-sensors. The floor sensor 32 is, as shown in FIG.
It is provided on a floor tunnel together with the microcomputer 16 and is provided near the driver's seat. The floor sensor 32 is constituted by a deceleration sensor in the present embodiment, and detects the deceleration in the front-rear direction near the driver's seat at the center of the vehicle body.
In this embodiment, the output signal of the floor sensor 32 is smoothed by a Kalman filter which is a dedicated electronic circuit and is configured by an analog circuit, and the smoothed signal is input to the microcomputer 16.

[0007] The two front sensors 34 and 36 are respectively provided on the left and right sides of the vehicle 30 and are provided on side frames constituting the vehicle body, and are provided on the left and right front portions of the vehicle body. In the present embodiment, each of the front sensors 34 and 36 is constituted by a deceleration sensor, and detects a deceleration in the front-rear direction of the left and right front portions of the vehicle body. In the present embodiment, the detection signals of the left and right front sensors 34 and 36 are smoothed by a Kalman filter which is a dedicated electronic circuit and is configured by an analog circuit. 3
The microcomputer 6 is divided into a plurality of levels, for example, 12 levels, by a microcomputer provided at the left and right front portions of the vehicle together with 6, and is inputted to the microcomputer 16 by, for example, current communication. In the present embodiment, the floor sensor 32, the front sensors 34, 36, and the Kalman filter for smoothing the output signals of these sensors constitute the electronic control unit 12 together with the microcomputer 16 and the drive circuit 18. Hereinafter, the front sensor 34 is referred to as a left front sensor 34, and the front sensor 36 is referred to as a right front sensor 36.

The microcomputer 16 outputs a start signal from the I / O circuit 28 to the drive circuit 18 so that the inflator 44
The air bag 14 is inflated by generating gas.
In the present embodiment, two inflators 44 are provided, and constitute a gas supply device 46. Each of the two inflators 44 has an ignition device 48 and a gas generating agent (not shown), and the drive circuit 18 energizes and ignites the ignition device 48 according to a start signal from the microcomputer 16. Thereby, the gas generating agent is ignited, gas is generated and supplied to the airbag 14, and the airbag 14 is inflated. If gas is simultaneously generated in the two inflators 44, the gas is supplied to the airbag 14 at a high speed, the airbag 14 is inflated at a high speed, and the two inflators 44 generate the gas with a time lag. Then, gas is supplied to the airbag 14 at a low speed, and the airbag 14 is inflated at a low speed. The gas supply device 46 is constituted by a multi-stage inflator, and the gas supply at a high speed of the gas supply device 46 is called a high mode, and the gas supply at a low speed is called a low mode.

The ROM 22 of the microcomputer 16 has
Various routines including a main routine, a soft crash detection routine, a vehicle center central deceleration maximum / minimum value acquisition routine, a left / right deceleration ratio acquisition routine, and a soft crash determination routine, each of which is represented by a flowchart in FIG. 8, are stored. Have been. Also, the RAM 24
As shown in FIG. 9, a detection value integral value memory 60 and the like are provided together with a working memory. PU20,
The above routine is executed while using the RAM 24.

[0010] The detection of a soft crash is performed based on the fact that the deceleration changes by drawing a unique waveform when a soft crash occurs. Floor sensor 32 and left and right front sensors 34, 36 when a soft crash occurs
If the output signal is smoothed by a filter, as shown in FIG. 10, the waveform once increases, then decreases and then increases again at the center of the vehicle body and at the front left and right portions of the vehicle body. In addition, the first maximum value which is the maximum value generated by the first increase / decrease is smaller than the second maximum value which is the maximum value caused by the second increase / decrease. In the vehicle provided with the airbag device 10 of the present embodiment,
The engine is located in the front part of the vehicle and is located away from the bumper. After the central part of the bumper collides with the collision object (for example, a utility pole), the engine is accompanied by elastic deformation and plastic deformation of the front part of the vehicle. When the vehicle body moves further forward, and then the high-strength engine collides with the collision target, a second large increase in deceleration occurs. Further, since the left and right front portions of the vehicle body collide with the collision target before the vehicle body center portion, the deceleration occurs at the vehicle body left and right front portions before the vehicle body central portion.

Three conditions for detecting a soft crash are set based on the change in the deceleration. The first condition is
The first maximum value of the longitudinal deceleration at the center of the vehicle body is larger than the first set deceleration and smaller than the second set deceleration.
The average value up to the maximum value, the maximum value front-back ratio obtained by dividing the average value from the first maximum value to the first minimum value that is the first minimum value is smaller than the first set ratio, and the third condition is The left-right ratio obtained by dividing the smaller front-rear deceleration by the larger front-rear deceleration among the front-rear decelerations at the left and right front portions of the vehicle body is larger than the second set ratio.

One example of a soft crash is a pole collision, as described above, but other forms of soft crash can be detected in accordance with the present invention. One example is a special form of underride collision. An underride collision is a collision in which the collision target has a portion with a large distance to the ground, such as a truck, and the vehicle plunges between the collision target and the ground. Rather, if a portion above the bumper and the side frame at the front of the vehicle collides with the collision object, a soft crash occurs. If the deceleration increases, decreases, and then increases again, and the collision satisfies the above three conditions, it can be detected as a soft crash.

An ignition switch (not shown) is turned on.
When the power is turned on, the main routine shown in FIG. 3 is executed. Step 1 of the main routine
Abbreviated as S1. Same for other steps. In step (1), initialization is performed, and the memory is cleared, initial values are set, flags and counters are reset, and the like. Then S2 is performed, the fourth whether the flag F ₄ is set determination is made. The fourth flag F ₄ is set, soft crash, positive collision or the like, represents that the various collision is detected, which is reset in the initial setting, the determination result of S2 are NO, the detection of the soft crash in S3 Is performed, a head-on collision is detected in S4, and a soft crash and a collision other than a head-on collision are detected in S5.

Then, in S6, it is determined whether or not the deceleration in the front-rear direction at the center of the vehicle body is greater than an ignition determination threshold value (abbreviated as "threshold value" in S6). The deceleration in the front-rear direction at the center of the vehicle body is obtained by reading the smoothed output signal of the floor sensor 32. The ignition determination threshold value is stored in the ignition determination threshold value memory 97 of the RAM 24, and the ignition determination threshold value memory 97 stores an initial value in an initial setting. In the present embodiment, this initial value is the maximum value among the ignition determination threshold values set for each of a plurality of types of collisions.

If the deceleration is equal to or less than the ignition determination threshold, S
The determination result in 6 is NO, and the execution of the routine returns to S2. If the deceleration is greater than the ignition determination threshold value, the determination result of S6 becomes YES, and S7 is executed to determine whether the operation mode of the gas supply device 46 is the high mode. This determination is made according to the contents of the gas supply device operation mode memory 99. In the present embodiment, the low mode is stored in the gas supply device operation mode memory 99 in the initial setting. If the operation mode is the high mode, the determination result in S7 is YES, and S8 is executed, and a high mode ignition command is output. An activation signal is output to the two drive circuits 18 at the same time, and the airbag 14 is inflated at a high speed. If the mode is the low mode, the determination result of S7 is NO, and S9 is executed.
A low mode ignition command is output. Two drive circuits 18
After a short time, the activation signal is output, and the airbag 14 is inflated at a low speed.

The setting of the fourth flag F ₄ , the setting of the ignition determination threshold value, and the setting of the operation mode of the gas supply device 46 are performed in any of the collision detection routines executed in S 3, S 4, and S 5. Is performed based on the detection of If it is the fourth flag F ₄ is set is detected collision in any of the collision detection routine, S2
Is YES, and steps S3 to S5 are skipped. Thereafter, no collision is detected in any of the routines, and the gas supply device 46 determines the set ignition based on the earliest detected collision. At the time determined by the threshold, the airbag 1 is activated in the set mode.
4 is inflated. Hereinafter, the detection of the soft crash will be described with reference to the flowcharts shown in FIGS. The detection of a head-on collision and the detection of other collisions are not directly related to the present invention and will not be described, but in the case of a head-on collision, the operation mode of the gas supply device 46 is set to the low mode. In the case of a head-on collision, the low mode and the high mode may be selected according to the collision situation, for example, the traveling speed of the vehicle.

In the soft crash detection routine, as shown in FIG. 4, the maximum value / minimum value of the deceleration at the center of the vehicle body is obtained in S11, the left / right deceleration ratio is obtained in S12, and the process proceeds to S13. A soft crash determination is made.

The acquisition of the maximum value / minimum value of the deceleration at the center of the vehicle body will be described with reference to the flowchart of FIG. In the routine for obtaining the maximum and minimum values of the deceleration in the center of the vehicle,
The first maximum value, the first minimum value, and the like are obtained based on the detection value of the floor sensor 32. The first maximum value and the minimum value may be obtained by storing all the detection values of the floor sensor 32, but the storage capacity is increased. For this reason, in the present embodiment, the detected values of the floor sensor 32 are integrated by a set number to obtain the average value of the longitudinal deceleration in the center of the vehicle body, and the average values of the decelerations before and after are compared to increase the deceleration. The detection of a transition from a deceleration to a decrease, thereby obtaining a first maximum, and the detection of a transition from a decrease in deceleration to an increase in deceleration, determines the first minimum. Also, until the first maximum value is obtained,
Integrating the deceleration and measuring the integration time to obtain the average value of the deceleration, and after obtaining the first maximum value,
The deceleration is integrated until the detection of the minimum value, and the integration time is measured to obtain an average value of the deceleration from the first maximum value to the first minimum value. The same applies to the detection of the first maximum value of the deceleration in the front-rear direction of the left and right front portions of the vehicle body based on the detection values of the front sensors 34 and 36 for obtaining the left-right deceleration ratio and the acquisition of the average deceleration.

First, in S21, the smoothed detection value (deceleration) of the floor sensor 32 is read. Next, S22 is executed, and the count value C ₁ of the first counter C ₁ is calculated.
Is determined whether or not is greater than or equal to a set value. It is determined whether the reading and integration of the detection value have been performed a set number of times (four times in the illustrated example). The determination result in S22 is NO at the beginning, and S23 is executed, and the smoothed detection value of the floor sensor 32 read in S21 is integrated. The value read in S21 is sequentially added to the value stored in the detection value integration value memory 60,
It is stored in the detected value integrated value memory 60 again. Further, the detected value integrated value memory 60 is cleared in the initial setting, and the initial value is 0. First count value C ₁ of the counter C ₁ is increased 1, the integral number of detected value is counted.

The integration number of the detection value of the floor sensor 32 is
By comparing the two successive deceleration average values, the number of times that a change in the deceleration from an increase to a decrease and a change from a decrease to an increase can be detected is set. The deceleration detected by the floor sensor 32 still contains some noise components even after smoothing, and does not necessarily monotonically increase or decrease. Therefore, even if there is an increase or decrease due to the noise component, the set number of times is constant until the deceleration reaches the first maximum value.
The magnitudes of the two average deceleration values obtained before and after are set to increase monotonically without inversion, and to decrease monotonically after reaching the first maximum value.

Until the detection value is integrated a predetermined number of times, S
Steps S21 to S23 are repeatedly executed. If reading of the detection value and integration are performed a set number of times, the determination result of S22 is YE
In S, S24 is executed, and the integrated values are averaged and stored in the current deceleration memory 62. The average value is obtained by dividing the integral value by the number of integrations. And the average value is set as the deceleration G _c. Deceleration G _c and stored in this deceleration memory 62 when the deceleration G _{c (t),} this deceleration is stored in the current deceleration memory 62 G _{c (t)} is ahead of times deceleration memory 6
The deceleration _{Gc (t-1)} is set to the previous deceleration _{Gc (t-1)} . In S24, the detected value integrated value memory 60 is cleared.

Next, S25 is executed, and the first flag F _{1 is set.}
It is determined whether or not is set. First flag F ₁ is reset in the initial setting, S25
Is NO, S26 is executed, and the deceleration G
_It is determined whether or not _c is greater than an increase start determination value G _thmin . The increase start determination value G _thmin is set to a value that can determine whether or not substantial increase in deceleration has started. Impact to the vehicle body is not limited to a vehicle collision, for example, but also imparted by unevenness of the road surface or the like, as long as it is small, the deceleration G _c is increased start determination value G
_{It is equal to} or less than _thmin , and the determination result in S26 is NO, and processing such as acquisition of the maximum value is not performed.

Deceleration G_cIs the increase start determination value G_thminThan
If it is larger, the determination result of S26 becomes YES and S27
Is executed, and the first flag F₁ Is set and deceleration G_c
Is the increase start determination value G_thminIs exceeded.
Next, S28 is executed, and the second flag F_TwoIs set
Is determined. Second flag F_Two Is
Note that the first maximum value of deceleration was obtained
Remember, it has been reset in the initial settings,
8 is NO, and S29 is executed.
The current time calculated in S24 is reduced by executing the routine.
Speed G_{c (t)}Is in S24 due to the execution of the previous routine.
Previous deceleration G calculated by_{c (t-1)}Judgment of whether or not
Is set. If the deceleration has increased, the current deceleration G
_{c (t)}Is the previous deceleration G_{c (t-1)}Larger, the result of S29
The result is YES, S30 is executed, and in S24
Calculated deceleration G_{c (t)}Is stored in the local maximum value memory 70.
Value. This time deceleration G_{c (t)}Decreased earlier
Speed G_{c (t-1)}With the above, the maximum value memory 70
The stored value is the current deceleration G_{c (t)}Is the previous deceleration G
_{c (t-1)}Maximum value of deceleration at the time when it is judged that it is above
And G_cmaxExpressed by max is an abbreviation of maximum.
Next, S31 is executed, and the deceleration G_{c (t)}Is integrated
It is stored in one deceleration integral value memory 66. Deceleration G_{c (t)}
Is integrated with the product stored in the first deceleration integral value memory 66.
The deceleration G calculated in S24 is added to the minute value. _{c (t)}(This time reduced
(Stored in the speed memory 62).
Is performed. The first deceleration integral value memory 66 is initialized.
And the initial value is 0. Also,
Second counter C_Two Count value C_Two Is increased by one
You. Maximum value G_cmaxThe number of updates made
Therefore, after the deceleration starts to increase, the first maximum
The time until the value is obtained is measured.

Steps S21 to S25 and S28 to S31 are repeatedly executed until the forward / backward deceleration changes from increasing to decreasing. Since the deceleration detected by the floor sensor 32 is smoothed and integrated and averaged in S21 to S24, the deceleration is the first local maximum value.
It continues to increase monotonically until it reaches a local maximum, and when the longitudinal deceleration changes from increasing to decreasing, a first maximum is obtained. If the deceleration changes from increasing to decreasing, the current deceleration G
_{c (t)} becomes smaller than the previous deceleration _{Gc (t-1)} . for that reason,
S29 in the determination result is executed S32 becomes NO, and the first maximum value G _Cmax1 is stored that is obtained second flag F ₂ is set. Accordingly, when S28 is executed next, the determination result is YES, and S30 is not executed. Maximum value G stored in local maximum value memory 70
The update of _cmax is not performed, and the value stored in the local maximum value memory 70 when the determination result of S29 is NO is determined as the first local maximum value _Gcmax1 . Note that this max
Is an abbreviation for maximal.

In S32, the first maximum value G
The average value G _camax of the longitudinal deceleration at the center of the vehicle body until _cmax1 is obtained is calculated and stored in the first average deceleration memory 74. This operation, the stored integration value in the first deceleration integration value memory 66 is performed by dividing the count value C ₂ of the second counter C _2. Acquisition of the first local maximum value, the deceleration G _c is performed is larger than an increase start determination value G _thmin, the time to acquire the first maximum value, from the deceleration G _c is increased start determination value G _thmin Since the time is measured from the state of the increase, the time before exceeding the increase start determination value G _thmin is not used for calculating the average value G _camax of the deceleration. The average value of the deceleration up to the first maximum value is calculated based on the deceleration and the time caused by the impact that the first maximum value is obtained for detecting the soft crash, and the impact occurs. The average value including the previously generated deceleration and time is not calculated, and the average value up to the first maximum value of the deceleration is accurately calculated for the impact to be subjected to the soft crash detection.

Next, S35 is executed, and the deceleration G _{c (t) is performed.}
With the integral value of is obtained, the count value C ₃ of the third counter C ₃ is increased 1. The integration is performed by adding the current deceleration _{Gc (t)} calculated in S24 to the value stored in the second deceleration integrated value memory 68,
The calculated value is stored in the second deceleration integral value memory 68. The second deceleration integrated value memory 68 is cleared in the initial setting, and the initial value is 0. After the first maximum value G _cmax1 is obtained, the calculation of the integral value of the deceleration from the first maximum value G _cmax1 to the detection of the first minimum value G _cmin1, which is the first minimum value, and measurement of the time are performed. It is done. The min of the first minimum value G _cmin1 is an abbreviation of minimal.

[0027] When the second flag F ₂ is set, the next time the S28 is executed, the determination result is YE
In S, S33 is executed to determine whether or not the current deceleration _{Gc (t)} is equal to or less than the previous deceleration _{Gc (t-1)} . Since the deceleration continues to decrease monotonically from the first local maximum value to the first local minimum value, ie, the first local minimum value, the determination result of S33 is YE
In S, S35 is executed. Then, until the deceleration changes from a decrease to an increase and the determination result of S33 becomes NO,
Steps S21 to S25, S28, S33, and S35 are repeatedly performed, and integration of the deceleration Gc _(t) and measurement of the integration time are performed.

If the deceleration changes from decreasing to increasing, the current deceleration Gc _(t) becomes larger than the previous deceleration Gc _(t-1) , and S3
The determination result of No. 3 is NO, and it can be seen that the deceleration has reached the minimum value. Then, S36 is executed, the average value G _camin of the deceleration from the acquisition of the first maximum value to the acquisition of the first minimum value is calculated, stored in the second average memory value for deceleration 76, and the third flag F _3. Is set and the average value G
It is stored that _camin was obtained. The calculation of the average value G _camin is performed by dividing the integrated value stored in the second deceleration integrated value memory 68 by the count value C ₃ of the third counter C ₃ . After the first maximum value G _cmax is obtained,
Even if the deceleration decreases and becomes equal to or less than the increase start determination value G _thmin , since the first flag F ₁ is set, the deceleration G _c calculated in S24 and the increase start determination value G _thmin are not _equal to each other. Are not performed, and the first minimum value is detected.

After execution of S11, a left / right deceleration ratio acquisition routine is executed in S12. In the left / right deceleration ratio acquisition routine, the first maximum values of the front / rear decelerations of the left and right front portions of the vehicle body are obtained based on the detection values of the left front sensor 34 and the right front sensor 36, respectively. The average value of the decelerations until the value is obtained is calculated, and the ratio of the average values of the left and right decelerations is calculated to calculate the ratio (left / right ratio) of the deceleration at the left and right front portions of the vehicle body. The first maximum value and the average value of the deceleration in each of the front-rear decelerations at the left and right front portions of the vehicle body are both reduced until the first maximum value and the first maximum value of the deceleration in the front-rear direction at the center portion of the vehicle body are obtained. Since it is obtained in the same manner as the average value of the speed, the description is omitted.

The parts specific to the left / right deceleration ratio acquisition routine will be described. The average value of the deceleration is obtained separately for the left front part of the vehicle body and the right front part of the vehicle body.
This is stored by setting the seventh flags F ₅ and F ₇ . If the average value of the deceleration is obtained for each of the front portions on the left and right sides of the vehicle, the determination results in S54 and S66 are both YES, and S67 is executed, and the left / right deceleration ratio (left / right ratio) is calculated. It is stored in the left / right deceleration ratio memory 98. This storage is performed by storing the calculated left / right deceleration ratio in the left / right deceleration ratio memory 98 instead of the value currently stored in the left / right deceleration ratio memory 98. In addition,
In the left / right deceleration ratio memory 98, an initial value is set to an initial value, for example, a value that is always smaller than a second setting ratio (the second setting ratio will be described later) for determining the left-right symmetry of a collision. ing. Then, that the left and right deceleration ratio ninth flag F ₉ is set is acquired and stored (S68).

[0031] If the left and right deceleration ratio is obtained, by the ninth flag F ₉ is set, the determination result of S41 is executed and S69 become to YES, determination of whether the set time has elapsed Is performed. The measurement of this time is, for example,
This is performed using a timer provided as a time measuring means provided in the PU 20. The determination result in S69 is NO at the beginning, and the execution of the routine ends.

If the determination of soft crash is not performed and the left / right deceleration ratio is not used for the determination, and the set time has elapsed, the determination result of S69 becomes YES and S70 is executed, and the left / right deceleration ratio is set. The various flags and counters used for the acquisition are reset, and the memories used for acquiring the left / right deceleration ratio, except the left / right deceleration ratio memory 98, are cleared, and again, The acquisition of the left / right deceleration ratio is performed. Depending on the impact, even when the deceleration exceeds the determination value for starting to increase at the left and right front portions of the vehicle body and the first maximum value is obtained, and the left / right deceleration ratio is calculated, the deceleration is determined to increase at the central portion of the vehicle body. , The first maximum value may not be obtained, and the soft crash determination may not be performed. Therefore, it monitors and detects whether the calculated left / right deceleration ratio has been used for soft crash determination, and if not used, newly obtains the left / right deceleration ratio and uses the left / right deceleration that has not been used. If the speed ratio is not discarded, when the first maximum value of the longitudinal deceleration at the center of the vehicle body is obtained and the soft crash is determined, the left / right deceleration ratio used for the determination and the first maximum value Is a value obtained by a different impact, and the soft crash cannot be correctly determined. Therefore, after the left / right deceleration ratio is acquired, the elapse of the set time is waited, and if the left / right deceleration ratio is not used for the determination of the soft crash, the acquisition is performed again. If the set time waited in S69 is a soft crash, after the left / right deceleration ratio is obtained, the currently obtained left / right deceleration ratio is acquired before the left / right deceleration ratio is obtained by the next impact. The length is set so that the first maximum value of the longitudinal deceleration at the center of the vehicle body is obtained by the impact. If the impact that caused the deceleration is a soft crash, the center of the vehicle will decrease in the front-rear direction before the set time elapses, or after the set time elapses, before the next left / right deceleration ratio is obtained. The first maximum value of the speed is obtained, and the soft crash is determined using the left / right deceleration ratio, the first maximum value, and the front-rear ratio before and after the same impact. Even after the set time has elapsed, the previously acquired left / right deceleration ratio is stored in the left / right deceleration ratio memory 98 until the next left / right deceleration ratio is acquired, and the soft crash determination is performed. Can be. If the soft crash is determined before the set time elapses, as described later, if it is determined that the soft crash has not occurred, the flag is reset as in S70, and the left and right deceleration is performed again. An acquisition of the ratio is performed. If it is determined that a soft crash has occurred, the acquisition of the left / right deceleration ratio is not performed thereafter. In the case of a soft crash, the set time may be slightly longer than the time from when the left / right deceleration ratio is obtained to when the first maximum value of the longitudinal deceleration in the center of the vehicle body is obtained.

After execution of S12, a soft crash determination routine is executed in S13. In soft crash determination routine, as shown in FIG. 8, a second flag F ₂ it is determined whether or not has been set is performed in S71. It is determined whether or not the first maximum value G _cmax1 of the longitudinal deceleration at the center of the vehicle body has been obtained. This determination result is NO until the first maximum value G _cmax1 is obtained, and S71 is repeatedly executed.

If the first maximum value G _cmax1 is obtained, S71
Is YES, and S72 is executed.
Flag F ₁₀ it is determined whether or not has been set is performed. Tenth flag F ₁₀ is is set when the first condition and the third condition of the soft crash is satisfied, are reset in the initial setting, the judgment result of S72 is executed S73 becomes NO, and First maximum value G _cmax1
Is larger than the first set deceleration G _th1 . The first maximum value G _cmax1 corresponds to the magnitude of the stress generated in the bumper at the time of the soft crash, but the generated stress is proportional to the traveling speed of the vehicle. Therefore, if determined the traveling speed should inflate the air bag 14 when the soft crash occurs, it determines the first maximum value G _Cmax1, first set deceleration G _{th 1} is of the soft crash to inflate the air bag If the first maximum value G _cmax1 is exceeded, the value must be exceeded (that is, a value smaller than the first maximum value G _cmax1 determined according to the traveling speed of the vehicle in which the airbag 14 is to be inflated and larger than the increase start determination value G _thmin ). Is set. If the first local maximum value G _cmax1 is equal to or less than the first set deceleration G _th1 , it is not a soft crash, and the determination result in S73 is NO, and S80 is executed to clear the memory,
The counter and the flag are reset, and the soft crash is detected again. What is cleared is the memory used for acquiring the first maximum value, the left / right deceleration ratio, and the maximum value front / rear ratio. The contents of the ignition determination threshold value memory 97 and the gas supply device operation mode memory 99 remain at the initial settings. Even if it is not a soft crash but a deceleration caused by an impact due to unevenness of the road surface, etc., the first maximum value is obtained if the increase start determination value G _thmin is exceeded, but the first condition is not satisfied. By
The determination as a soft crash is avoided. The same applies to the second and third conditions. If those conditions are not satisfied, the memory is cleared and the like is performed again.
A soft crash detection is performed.

First maximum value G_cmax1 Is the first set deceleration G
_th1 If it is larger, the determination result of S73 is YES.
S74 is executed, and the first maximum value G_cmax1 Is reduced by the second setting
Speed G _th2 A determination is made whether it is less than. Second setting
Constant deceleration G_th2 Is set to a value that eliminates head-on collisions.
You. As mentioned above, during a head-on collision, a large deceleration
, The second set deceleration G_th2 Is shown in FIG.
Thus, the first maximum G due to the soft crash_cmax1 so
Does not exceed, but exceeds the deceleration caused by a collision
Is set to a value.

The first maximum value G_cmax1 Is the second set deceleration G
_th2 If so, it is not a soft crash, but S74
Is NO, and S80 is executed. First pole
Large value G _cmax1 Is the second set deceleration G_th2 If smaller,
When the result of the determination in S74 is YES, S75 is executed, and
The left / right deceleration ratio stored in the left / right deceleration ratio memory 98 is
A determination is made as to whether the ratio is greater than the two set ratios. Left / right deceleration
The closer the power ratio is to 1, the higher the left-right symmetry, and the second setting ratio
Is 0.8 in the present embodiment.

If the left / right deceleration ratio is equal to or less than the second set ratio,
Instead of a soft crash, the determination result of S75 is NO and S80 is executed. If the left / right deceleration ratio is larger than the second set ratio, the determination result of S75 becomes YES and S
76 is executed, the tenth flag F ₁₀ is set. The fact that the first and third conditions of the soft crash are satisfied is stored. Then S77 is executed, the third flag F ₃ it is determined whether or not has been set is performed. It is determined whether or not the average value of the deceleration from the first maximum value to the first minimum value of the deceleration in the front-rear direction at the center of the vehicle body is obtained. Unless this average value is obtained, the third flag F ₃ is not set, the judgment result of S77 is to NO. Then, S71, S72, and S77 are repeatedly executed, and the acquisition of the average value is awaited.

If the average value is obtained and the third flag F ₃ is set, the determination result in S77 becomes YES and S78
Is executed, and it is determined whether or not the maximum value front-back ratio is smaller than the first set ratio. The maximum front-to-back ratio is determined by the aforementioned S32, S
Using the deceleration average values G _camax and G _camin calculated in 36 and stored in the first and second average deceleration values memories 74 and 76, the deceleration average up to the first maximum value G _cmax1 is used. the value G _{cama x,} is determined by dividing the deceleration average value G _Camin from the first local maximum G _Cmax1 to the first minimum value _G cmin1. If it is a soft crash, [Problems to be solved by the invention, means to solve the problems and effects]
As described in the item (1), the first maximum value G
_When the deceleration up to _cmax1 and the deceleration from the first maximum value _Gcmax1 to the first minimum value _Gcmin1 are averaged and compared, the latter average value is often smaller than the former average value. On the other hand, in the case of a head-on collision or a bad road surface,
The ratio before and after the maximum value becomes a large value. First setting ratio in view of the circumstances, the deceleration average value G _{cami n} and the deceleration average value G
_The value is set to a value at which a soft crash can be detected based on the ratio with _camax , set according to the type of vehicle, and set to a value around 1.

As described above, the integration of deceleration and
The measurement of the time until the first maximum value is obtained is the deceleration G_cIncreases
Start judgment value G_thminIs performed from the time when the
Average value of deceleration G until value is obtained_camaxIs the deceleration
G_cIs the increase start determination value G_{thmi n}Deceleration until exceeding
And is sought without including time. Deceleration G _c
Is the increase start determination value G_thminDeceleration up to
The average of the deceleration until the first maximum value is obtained including the time
Average G_camax, The average value G_camaxIs small
The maximum ratio before and after the soft crash
Not less than the fixed ratio, soft crash is detected and loss
Deceleration G_cIs the increase start determination value G
_thminThe first maximum without including the time to exceed
Average value G of deceleration until is obtained_camaxIs required
Therefore, it is determined whether the ratio before and after the maximum value is smaller than the first set ratio.
The judgment is made accurately.

If the maximum front-to-back ratio is equal to or greater than the first set ratio,
Instead of a soft crash, the determination result in S78 is NO and S80 is executed. If the maximum front-to-back ratio is smaller than the first set ratio, the determination result in S78 is YES. Thus it is that the three conditions of the soft crash all satisfied, S79 is performed, together with the fourth flag F ₄ is set collision detection is stored, the ignition determination threshold and a gas supply device 46 The operation mode is set. The ignition judgment threshold in soft crash is
For example, as shown in FIG. 10, the value is set to a value larger than the first maximum value G _{cmax1 and} smaller than the second set deceleration G _th2 , and stored in the ignition determination threshold value memory 97. The operation mode is set to the high mode and stored in the gas supply device operation mode memory 99.

If a soft crash is detected, when S6 is executed in the main routine, the deceleration is compared with an ignition determination threshold set based on the detection of the soft crash. The ignition determination threshold is set to be larger than the first maximum value and smaller than the second set deceleration, and smaller than the ignition determination threshold set by detecting a collision other than a soft crash such as a head-on collision. For this reason, the soft crash is not detected until the first minimum value occurs, and it takes a longer time to detect the soft crash than a head-on collision or the like, but after detection, a delay in ignition is avoided. Until the deceleration exceeds the ignition determination threshold, S2 and S6 are repeatedly executed. If the deceleration exceeds the ignition determination threshold, the determination result of S6 becomes YES and S
7 is executed. Since the operation mode of the gas supply device 46 is set to the high mode, the determination result in S7 is YES.
Then, S8 is executed, and a start signal is output to the two drive circuits 18 at the same time. As a result, the two inflators 44 simultaneously activate the ignition devices 48, and the airbag 1
4 is inflated at high speed. For this reason, the detection of the soft crash as described above takes a longer time than a head-on collision, but the occupant can be sufficiently protected in conjunction with the avoidance of the ignition delay.

By detecting the soft crash under the three conditions as described above, for example, as shown by a two-dot chain line in FIG. 11, the road surface condition is poor, and the deceleration increases and decreases, thereby increasing the maximum value and the minimum value. Even if two values occur, detection of a soft crash thereby can be avoided. In this case, even if the first and third conditions are satisfied, the time from the first local maximum value to the first local minimum value is short, and the first local maximum value is large. This is because the ratio becomes larger than one set ratio. Note that the solid line in FIG. 11 shows a change in deceleration due to a soft crash that occurred at a relatively low speed. VN on the horizontal axis is the integral value of the longitudinal deceleration at the center of the vehicle body.

As is apparent from the above description, in the present embodiment, the part of the microcomputer 16 that reads the smoothed detection value of the floor sensor 32 (the part that executes S21) is the vehicle center central deceleration acquisition means. Configure and RAM 24
, The part executing S29 and S30 constitutes the first maximum value acquiring means, the part executing S33 using the RAM 24 constitutes the first minimum value acquiring means, and S31 and S3
2, S35 and S36 constitute a deceleration average value acquiring means, and S43 to S53 and S55 to S65 constitute a left and right front deceleration acquiring means.
4, S67, S73, S74, S75, S78
Is a part of the determination means, and the part that performs S8 and S9 and the drive circuit 18 form an inflator control device. Further, the part that executes S69 and S70 constitutes a left / right deceleration ratio reacquisition starting unit, a left / right deceleration ratio updating unit, a left / right deceleration ratio discarding unit, or a left / right deceleration ratio use monitoring unit. Further, a Kalman filter for smoothing the detection values of the floor sensor 32 and the front sensors 34 and 36 constitutes a smoothing means. In the present embodiment, the floor sensor 32 and the front sensors 34 and 3 are used.
6 and the Kalman filter constitute a soft crash detection device together with the vehicle body central portion deceleration acquisition means and the like.

In the above-described embodiment, when the longitudinal deceleration of the central portion of the vehicle body that has increased has turned from increasing to decreasing at least once, that is, even if the value stored in the first maximum value memory is once, The first local maximum value is determined when the deceleration becomes larger than the calculated deceleration immediately after. However, the maximum value stored in the local maximum value memory is continuously detected the set number of times and then detected. If the deceleration is larger than the deceleration, the first deceleration may be acquired assuming that the longitudinal deceleration has changed from increasing to decreasing. For the first minimum,
If the minimum value stored in the minimum value memory is continuously smaller than the set number of times and the next detected deceleration, it is determined that the longitudinal deceleration has changed from decreasing to increasing, and the first minimum value is acquired. You may do so. The examples are shown in FIGS.
It will be described based on.

In this embodiment, the maximum value of the deceleration at the center of the vehicle
The configuration is the same as that of the above-described embodiment except that the minimum value acquisition routine, the left / right deceleration ratio acquisition routine, and the configuration of the RAM are different. The acquisition of the maximum value and the average deceleration value in the left / right deceleration ratio acquisition routine is performed in the same manner as in the above-described embodiment. Since the processing is performed in the same manner as the acquisition of the value, the illustration and description of the routine are omitted, and a part of the configuration of the RAM is shown in FIG.

The outline of the acquisition of the first maximum value of the longitudinal deceleration at the center of the vehicle is as follows. A plurality of detected values of the floor sensor are integrated and averaged to obtain one averaged deceleration. Each time, compare with the maximum value stored in the local maximum value memory,
The state in which the maximum value is equal to or greater than the deceleration is the set number of times (N
If it is continuous, the maximum value is determined as the first maximum value. After the deceleration determined to be the first maximum value is obtained,
The first maximum value is determined when N (the same number as the set number of times) decelerations are acquired. In addition, the integration of the deceleration for calculating the deceleration average value until the first maximum value is obtained is calculated from the latest deceleration in which the magnitude is compared with the maximum value stored in the maximum value memory by N pieces. Is performed for the deceleration going up. Therefore, N decelerations that go backward from the latest deceleration are stored in separate memories so that integration is performed, and when a maximum value is obtained, the deceleration integral value becomes just the maximum value. This is a value obtained by integrating the determined deceleration.

A case where the set number of times that the deceleration is equal to or more than three times because the maximum value is determined to the first maximum value is set as an example.
This will be briefly described with reference to FIG. As shown in FIG. 15A, the deceleration G _{c (t) that} is later determined to be the first maximum value is:
The deceleration currently stored in the local maximum value memory (for example, G
_{c (t-1)),} and is larger than the deceleration, so that it is stored in the local maximum value memory instead. Then, the integration of the deceleration is performed for the deceleration _{Gc (t-3) three} times before. Note that in FIG. 15A, the symbol S ₁ is the deceleration G
Indicates the integral value of deceleration until _{c (t-3)} is added. The integration is performed for the deceleration three times before because the number of times that the value stored in the local maximum value memory becomes continuously equal to or more than the next deceleration is 3 in order to determine that the deceleration has changed from increasing to decreasing. The deceleration G
_The three decelerations going up from _{c (t)} are stored separately in memory. Further, the deceleration exceeds the increase start determination value, if a value C ₁ in which the maximum value of deceleration is counted by the counter to time to obtain the deceleration G _{c (t-3)} is obtained the time when the a (C ₁ -3).

As shown in FIG. 15 (b), the deceleration G _{c (t)}
Of the calculated deceleration G _{c (t + 1)} The following, although compared with the deceleration G _c stored in the maximum value memory _(t), the deceleration G
_{Since c (t + 1)} is smaller, the local maximum is not updated. The integration of the deceleration is determined by the deceleration _{Gc (t-2)} three times before the deceleration _{Gc (t + 1 ).}
Done for the integrated value S ₂ (integral value obtained by adding the G _{c (t-3)} to S ₁₎ in the deceleration G _{c (t-2)} is added, the integral value S ₃ is obtained. Then, as shown in FIG. 15 (c), the deceleration G _{c (t + 1)} following to the calculated deceleration G _c of _{(t + 2)} be the deceleration G
_{Since it} is smaller than _{c (t)} , the maximum value is not updated, and the integration of the deceleration is performed for the deceleration _{Gc (t-1)} three times before the deceleration _{Gc (t + 2)} . Furthermore, as shown in FIG. 15 (d), the deceleration G _{c (t + 2)} next to the calculated deceleration G _c of _{(t + 3)} also deceleration G
_{Since it} is smaller than _{c (t)} , the local maximum is not updated. At this time, the deceleration _{Gc (t)} stored as the maximum value in the local maximum value memory is continuously performed three times, the decelerations _{Gc (t + 1)} , _{Gc (t + 2)} ,
It is found that it is larger than _{Gc (t + 3)} , and it is determined to be the first maximum value. Further, the integration of the deceleration is performed for deceleration G _{c (t + 3)} of the three previous deceleration G _{c (t),} when the first maximum value is determined, is just the first maximum value deceleration integration value obtained by adding obtain an average value of the deceleration to obtain first maximum value, the integral value, the count value C ₄ when the deceleration G _{c (t + 3)} are computed 3 is a value obtained by subtracting the first local maximum deceleration G _{c (t)} is calculated by dividing the count value C ₁ when the computed.

The acquisition of the first maximum value and the like will be described based on the routine for acquiring the maximum value and the minimum value of the deceleration at the center of the vehicle body. In this routine, the number of times that the maximum value stored in the local maximum value memory must be continuously larger than the next calculated deceleration in order to determine that the deceleration has changed from increasing to decreasing. Is, for example, three times. S101
Steps S103 to S103 are executed similarly to steps S21 to S23 of the routine for acquiring the maximum value / minimum value of the deceleration at the vehicle body center in the above-described embodiment, and the reading and integration of the detected value are performed a set number of times. If the reading and integration of the detection value have been performed a set number of times, for example, twice, the determination result of S102 becomes YES and S104 is executed, and the integration values are averaged. And the average value is set as the deceleration G _c. Also in S104, the integral of the deceleration G _c is carried out, the values stored in the first deceleration memory 104 is added to the value stored in the deceleration integration value memory 112. The integration is performed in the first to third deceleration memories 104 to
108 out of the stored deceleration, an oldest deceleration from the calculated deceleration G _{c (t)} in S104 3
This is performed for the value that has gone up. After the integration, the value stored in the first deceleration memory 104 is erased, and the value stored in the second and third deceleration memories 106 and 108 is changed to the first and second deceleration memories 104 and 108, respectively. 106
Transferred to the newly computed deceleration G _c it is stored in the third deceleration memory 108. Then, the detection value integration-value memory 102 is cleared, the count value C ₉ of the ninth counter C ₉ is increased 1. Than is the integration time of the deceleration G _c is measured.

Next, S105 to S107 are performed in S25 to S107.
This is executed in the same manner as in S27, and it is determined whether or not the substantial increase in the deceleration has started. However, in the present embodiment, the increase start determination value G _thmin is set to be larger than the increase start determination value G _thmin (the first set deceleration G
_When the deceleration increases, the latest deceleration Gc _(t) among the three decelerations stored in the first to third deceleration memories 104 to 108 is equal to or smaller than _th1. The magnitude is set to exceed, but not exceed the deceleration _{Gc (t-1)} obtained immediately before. Therefore, when the deceleration G _{c (t)} exceeds the increase start determination value G _thmin , the deceleration is definitely in the increase state, and the three decelerations (the increase start determination value G _thmin It is highly likely that all of the three decelerations stored in the first to third deceleration memories 104 to 108 at the time when the decelerations exceeding the deceleration are calculated are all values at the time when the deceleration increases. . Further, the integration of the deceleration and the calculation of the average of the deceleration at the time of obtaining the local maximum value are performed including three decelerations and the time which are reverse to those at the time of the calculation of the deceleration that first exceeds the increase start determination value. Therefore, the deceleration integrated value memory 112 is cleared in S107,
The third to fourth deceleration memories 104 to 108 are not cleared, and the count value C ₉ of the ninth counter C ₉ is reset to 3.

Increase start judgment value G_thminDeceleration G exceeding
_cOccurs, the determination result in S106 becomes YES and S
108 is executed, and the eleventh flag F₁₁Is set.
Then, S109 is executed and the twelfth flag F₁₂Is set
It is determined whether or not the flag has been set.
F₁₂Is reset in the initial setting, so S1
The determination result at step 09 is NO, and step S110 is executed.
Speed G_cIs the maximum value stored in the local maximum value memory 118
G_cmaxIt is determined whether or not this is the case. Deceleration G_c
Is the maximum value G_cmaxIf so, the determination result of S110 is Y
ES, S111 is executed, and the deceleration G_cIs the maximum value
G_cmaxIs replaced by a new maximum value G _cmaxAnd
Both are the 10th counter C_TenIs reset. Tenth
Counter C_TenIs the maximum value G_cmaxIs the newly obtained deceleration
G_cLarger, continuous maximum value G_cmaxIs updated
The maximum value G to count_cmaxIs updated
If they do, they will be reset.

[0052] In contrast, if the deceleration G _c is smaller than the maximum value G _cmax, the determination result of S110 is turned NO S1
12 is executed, the count value C ₁₀ of the 10 counter C ₁₀
Is increased by one. Newly calculated deceleration G _c is smaller than the maximum value G _cmax, is the number of times the updating is not performed of the maximum value G _cmax is counted. Then, S113 is executed, the number of times the count value C ₁₃ is set in advance, it is determined whether for example, at least three times is carried out.

If the deceleration increases while repeatedly increasing and decreasing,
Before the first maximum value is obtained, the deceleration is stored in the maximum value memory 11.
It may be less than 8 on the stored value, in which case the maximum deceleration before the count value C ₁₀ of the 10 counter C ₁₀ becomes 3 is stored in the maximum value memory 118 G be more than _cmax, the tenth counter C ₁₀ in S111 is reset, the determination of the conversion to decrease from increase of the deceleration starts over.

If the maximum value G _cmax stored in the local maximum value memory 118 continuously becomes larger than the immediately following three decelerations G _{c (t)} , the determination result in S113 is YES.
Turned in the S114 is executed, the 12 flag F ₁₂ is set. Thereby, next time S109 is executed,
The determination result is YES, and S110 to S114 are not executed. The update of the maximum value stored in the local maximum memory 118 is not performed, and when the determination result in S113 is YES, the maximum value G _cmax stored in the local maximum memory 118 is changed to the first local maximum G _Obtained as _cmax1 . The maximum value stored in the maximum value memory 118 is the first value.
In order to determine that the deceleration is the maximum value, the number of times that the deceleration becomes larger than the deceleration calculated immediately after may be set to the number of times that the change from the increase to the decrease in the deceleration can be reliably detected.

In S114, an average deceleration value G _camax until the first maximum value is obtained is calculated. In this calculation, the integral value stored in the deceleration integral value memory 112 is
It is performed by dividing the ninth counter value obtained by subtracting three from the count value C ₉ of C _9. Integration is based on the latest deceleration G _{c (t)}
S3 is performed for the deceleration that is three times higher than
When the determination result of step 3 is YES, the deceleration integral value is
The first maximum value G _cmax1 stored in the maximum value memory 118 is an integrated value, and this value is obtained by subtracting 3 from the count value C ₉ of the ninth counter C ₉ , that is, the first value. The ninth counter C ₉ when the maximum value is calculated
, The average value of the deceleration up to the first maximum value G _cmax1 is obtained. The value obtained by this calculation is stored in the first deceleration average value memory 122. Further, stored in the maximum value obtaining during deceleration integration value maximum value obtaining during deceleration integration-value memory 114, the count value C ₉ of the ninth counter C _9, i.e. the maximum value acquisition time maximum value of the time during acquisition memory 116. Further, a tenth counter C ₁₀ is reset. Further, the minimum value memory 12
A value of 0 is set to the first local maximum G _cmax1 .

[0056] Incidentally, as described above, in the determination of S106, the deceleration when G _c is less increase start determination value G _thmin, deceleration integration-value memory 112 in S107 is cleared, the first to third Deceleration memory 104-108
Is not cleared, the count value C ₉ of the ninth counter C ₉ is reset to 3. Therefore, the integral value and the integration time of the deceleration include three decelerations and time that are _reversely increased from the deceleration that first exceeds the increase start determination value G _thmin , and the increase start determination value is An average value of the deceleration up to the acquisition of the first maximum value including the deceleration not exceeding is calculated. As described above, the increase start determination value G _thmin is set to be relatively high, and the three decelerations acquired before the deceleration that first exceeds the increase start determination value G _{th min} are also values that are in the increase state. It is highly probable that the average value including these decelerations is calculated, so that the average deceleration value is more accurately obtained. The execution of S106 eliminates the minute deceleration caused by causes other than the soft crash.
It is the same as in the previous embodiment.

The twelfth flag F₁₂By setting of S10
9 is YES and S115-119 are executed.
Then, a first minimum value is obtained. The first minimum is the first minimum
Similarly to the maximum value, the maximum value stored in the minimum value memory 120 is stored.
Obtained by comparing the small value with the deceleration calculated immediately after.
It is. Deceleration G obtained in S104_{c (t)}Is the minimum value
The value is compared with the minimum value stored in the memory 120. Decrease
Speed G_{c (t)}Is the minimum value G _cminIf below, the deceleration G
_{c (t)}Is the minimum value G stored in the minimum value memory 120.
_cminIs replaced by Minimum value G_cminIs set continuously
Number, eg 3 times, deceleration G_{c (t)}S until it becomes larger
101 to S105, S109, S115 to S118 are repeated.
And the integration of the deceleration and the measurement of the integration time are performed.
You. The integral of the deceleration is stored in the local minimum value memory 120.
This is performed for three decelerations that have gone up from the current deceleration.
Minimum value G_cminIs deceleration G three times in a row_{c (t)}Bigger
If the state continues, the determination result of S118 becomes YES,
The minimum value G stored in the minimum value memory 120_cmin
Is determined to be the first minimum value. Then, S119 is executed.
The deceleration flat from the first maximum value acquisition to the first minimum value acquisition
An average value is calculated. This calculation is performed in the deceleration integrated value memory 1
Deceleration at the time of obtaining the maximum value from the deceleration integral value stored in 12
Deceleration at the time of obtaining the maximum value stored in the degree integrated value memory 114
The value obtained by subtracting the degree integration value is determined as YES in S118.
9th counter C when it becomes₉ Count value C₉ From
The maximum value acquisition time is stored in the maximum value acquisition time memory 116.
9th counter C at₉ Subtract the count value of
Is performed by And the tenth counter C_TenIs Lise
Is set. Note that the soft crash determination routine
When the first to third conditions are not satisfied,
Is performed, but in the present embodiment, the first
-The third deceleration memories 104 to 108 are not cleared,
9 counter C₉ Is reset to 3. Other memory
Is cleared, the flag is reset, and the counter is reset to 0.
Reset.

If the maximum value and the minimum value are temporarily compared with a plurality of deceleration values to obtain the maximum value and the minimum value, the deceleration is smaller than the maximum value or the minimum value. The maximum value and the minimum value are not determined by one occurrence of the larger state, and the maximum value and the minimum value can be acquired more reliably. At this time, an average value is obtained by integrating a plurality of detection values, and instead of comparing the average value with the local maximum value, a deceleration that is a smoothed detection value of the sensor and is not averaged is used. The first maximum value may be obtained by comparing with the maximum value.

In each of the above embodiments, the left / right deceleration ratio is calculated based on the average value of the deceleration when the first maximum value of the forward / backward deceleration is obtained for each of the left and right front portions of the vehicle body. When the first maximum value is detected for any one of them, the left / right deceleration ratio may be calculated. An example thereof will be described based on the flowcharts shown in FIGS. The configuration of the RAM for implementing these flowcharts is the same as that of the embodiment shown in FIGS.

In the left / right deceleration ratio acquisition routine of this embodiment, the left and right front portions of the vehicle body are separately
A plurality of detection values of the left and right front sensors are integrated to obtain an average value (S202 to S205, S212 to S21).
4) When the deceleration obtained by the average has substantially increased beyond the increase start determination value (S206 to S20)
8, S215 to S217), the first maximum value is detected by comparing two successive decelerations (S209, S21).
8). However, even if one of the left and right decelerations does not exceed the increase start determination value, if the other exceeds, the detection of the first maximum value is started in one of them (S206, S21).
5). While the deceleration is increasing, the deceleration is integrated and the integration time is measured by a counter (S210, S219). When the first maximum value is detected in one of the left and right decelerations, the left and right decelerations are measured. The average value of each deceleration is calculated, the left / right deceleration ratio is calculated and stored in the memory (S220, S221). When the calculated left / right deceleration ratio is stored in the left / right deceleration ratio memory, it is stored in place of the value currently stored in the left / right deceleration ratio memory. And
By setting the flag (S222), the fact that the left / right deceleration ratio has been obtained is stored, and S223 and S224 are executed in the same manner as S69 and S70 in the above-described embodiment. After the elapse, the flag is reset. In this embodiment, the microcomputer S
The part that executes steps 202 to S220 constitutes the right and left front deceleration acquisition means.

The left / right deceleration ratio may be acquired when the first maximum value of the longitudinal deceleration at the center of the vehicle body is acquired. An example will be described based on the flowchart shown in FIG. Although the configuration of the RAM for executing the flowchart shown in FIG. 18 is not shown, of the RAM of the embodiment shown in FIGS. 1 to 11, the current deceleration memory for the left and right fronts, the previous deceleration A memory excluding the memory, and a memory for storing whether the deceleration detected by the left or right front sensor has exceeded the increase start determination value. Thus, the configuration includes a fifteenth counter, a sixteenth counter, and a sixteenth flag.

In the left / right deceleration ratio acquisition routine of this embodiment, the detection value of the front sensor is read, the detection value of the front-rear deceleration of the front part of the vehicle body is integrated, the number of integrations is counted, the average deceleration value is calculated, The integration of the deceleration and the counting of the number of integrations are performed simultaneously on the left and right sides (S301 to S304,
S309, S310). Although the counting of the number of integrations is performed using a counter common to the left and right, integration and calculation are performed separately for the left and right, and the obtained values are stored in dedicated memories for left and right. The count of the integrator and the integral number of deceleration is started when one of the front-rear direction deceleration of the vehicle body right and left front exceeds the increase start determination value, the set of the 16 flag F _16, deceleration The fact that the deceleration detected by the left or right front sensor has exceeded the increase start determination value is stored in the memory while the fact that the increase has exceeded the increase start determination value is stored (S305 to S308).

Then, the integration of the deceleration and the integration
After the unloading is performed (S309, S310),
Whether the first maximum value of the longitudinal deceleration of the part has been obtained
A determination is made (S311). As described above, this first
Flag is set if local maximum is obtained
This flag is set in the judgment of S311.
This is performed depending on whether or not it has been performed. First maxima are obtained
If not, the determination result in S311 is NO and S
317 is executed, and the count value C₁₆Is the set value C _thAbove
A determination is made whether there is. Deceleration starts to increase
It is determined whether or not the set time has elapsed since
The determination result of S317 is initially NO.
You. The reason for making the determination in S317 will be described later.

[0064] By the 16 flag F ₁₆ deceleration exceeds the increase start determination value is set, the next time the S305 is executed, the determination result is turned YES S314
Is executed, and it is determined whether or not the deceleration obtained by the detection value of the front sensor that has detected the deceleration exceeding the increase start determination value has become equal to or less than the increase start determination value. The deceleration decreases after increasing, but if the deceleration is greater than the increase start determination value, the determination result in S314 becomes NO and S309 is executed.

Until the first maximum value of the longitudinal deceleration at the center of the vehicle body is obtained, steps S301 to S305, S314, S
309 to S311 and S317 are repeatedly executed. After the deceleration exceeds the increase start determination value, even before the count value C ₁₆ of the 16 count C ₁₆ exceeds the setting value C _th, the front sensor detects a deceleration greater than the increase start determination value detecting before deceleration G _f obtained based on the value becomes less increase start determination value G _thmin, if it is acquired first maximum value, S312 is executed the determination result of S311 becomes to YES, the left and right deceleration After each average value is calculated, S31
3 is executed, the left / right deceleration ratio is calculated based on the average value, and is stored in the left / right deceleration ratio memory instead of the value currently stored in the left / right deceleration ratio memory.

On the other hand, before the first maximum value is obtained.
If the deceleration becomes equal to or less than the increase start determination value,
4 is YES, and S315 is executed.
Front sensor that detects deceleration exceeding the large start judgment value
Integrated value S of deceleration obtained from the detection value of_GIs set integral
Value S_GTHA determination is made whether it is greater than. Deceleration
Integral value S_GIs the set integral value S_GTHIf it is below, S315
Is NO, S316 is executed, and both left and right
The deceleration integral value memory is cleared and the first
6 counter C₁₆, The 16th flag F₁₆Is reset.
Integrated value S of deceleration _GIs the set integral value S_GTHIf
An impact that caused the deceleration to exceed the increase start judgment value occurred.
The impact is small, the impact caused by soft crash
There is no, so I calculated to get the left / right deceleration ratio
Discards values, etc. and is not used for soft crash judgment
To calculate the left / right deceleration ratio again,
The judgment or the like is performed.

[0067] In contrast, greater than the deceleration integration value S _G is set integrated value S _GTH, the determination result of S315 is YES
And S310 is executed. In this case, the deceleration integral value obtained from the time when the deceleration exceeds the increase start determination value to the time when the deceleration becomes equal to or less than the increase start determination value is left as it is, and the integration of the deceleration is not performed. Measure (S31
0), it is determined whether or not the set time has elapsed before the first maximum value is obtained (S311 and S317). If deceleration integrated value S _G is greater than the set integrated value S _GTH, the deceleration integration value are likely caused by software crash, but than is leaving, the deceleration exceeds the increase start determination value Therefore, if the first maximum value is not obtained even after the set time has elapsed, the deceleration integrated value is not the value obtained by the soft crash, and the deceleration integrated value is cleared and the left / right deceleration ratio at the time of the actual soft crash occurrence is cleared. It is not used for acquisition.

If the first maximum value is obtained before the count value C ₁₆ becomes equal to or more than the set value C _th , the determination result of S311 becomes Y
When ES is established, S312 and S313 are executed, and the left / right deceleration ratio is calculated and stored. Since the left / right deceleration ratio is calculated based on the acquisition of the first maximum value, the determination of the soft crash is always performed when the left / right deceleration ratio is acquired. Then, if it is not a soft crash, a reset or the like of the odor flag is performed in the soft crash determination routine, and the left / right deceleration ratio is obtained again. As described above, in the present embodiment, the S
The part that executes 302 to S312 constitutes the left / right front deceleration acquisition means.

In some of the above-described embodiments, after the acquisition of the left / right deceleration ratio, the determination of the soft crash is not performed. If the acquired left / right deceleration ratio is not used to determine the soft crash once, the acquisition of the left / right deceleration ratio is repeated and the previously acquired left / right deceleration ratio is discarded to determine the soft crash. Was performed using the left-right deceleration ratio obtained by the same impact, the first maximum value of the front-rear deceleration at the center of the vehicle body, and the maximum value front-rear ratio. The invention is not limited to this. For example, it is determined whether the first maximum value of the longitudinal deceleration detected for the front part of the vehicle body is equal to or smaller than a set value. To Good. If the left / right deceleration ratio is calculated when the first maximum value of the longitudinal deceleration is detected for one of the left and right front portions, the value is compared with the set value when the first maximum value is obtained. If it is equal to or smaller than the set value, the acquisition of the left / right deceleration ratio is performed again. When the left / right deceleration ratio is calculated when the first maximum value of the longitudinal deceleration is detected for both the left and right front parts, both first maximum values are compared with the set values, and at least one of the first maximum values is compared. If is smaller than the set value, the acquisition of the left / right deceleration ratio is performed again. When the first maximum value is compared with the set value and is equal to or smaller than the set value and the acquisition of the left / right deceleration ratio is performed again, the deceleration is still in a decreasing state. When the two decelerations acquired by the comparison are detected by detecting that the later acquired deceleration is smaller than the previously acquired deceleration, it is determined that the first maximum value is equal to or less than the set value. Thereafter, the acquisition of the next first maximum value (acquisition of the left / right deceleration ratio) can be started immediately. In this case, each of the acquired decelerations is the first until the deceleration changes from decreasing to increasing.
The maximum value is set and compared with the set value. However, since these values are all equal to or smaller than the set value, the left / right deceleration ratio is not calculated, and the acquisition of the left / right deceleration ratio is started repeatedly. If the deceleration changes from decreasing to increasing, the first
Until the maximum value is obtained, the comparison with the set value is not performed. When the deceleration changes from increasing to decreasing and the first maximum value is obtained, the comparison is made with the setting value. When it is determined that the first maximum value is equal to or smaller than the set value, it is not necessary to set a time, for example, and wait for the start of the acquisition of the first maximum value (left / right deceleration ratio) again. When the first maximum value exceeding the set value is generated, the left / right deceleration ratio is calculated. In this case, after acquiring the left / right deceleration ratio, it is monitored whether or not the acquired left / right deceleration ratio has been used for the determination of a soft crash. It is desirable to discard the left / right deceleration ratio that has not been set. Until the first local maximum value exceeding the set value does not occur until the soft crash occurs, the left / right deceleration ratio remains at the initial value, and the left / right deceleration ratio is calculated for the first time by the impact due to the soft crash. The first maximum value and the maximum value front-rear ratio of the deceleration in the front-rear direction at the center of the vehicle body are acquired and a soft crash determination is performed, and it is monitored whether the left-right deceleration ratio is used for the soft crash determination. It is not essential. On the other hand, when the first maximum value of the front-rear deceleration at the front left and right of the vehicle body exceeds the set value and the left-right deceleration ratio is calculated, but the first maximum value of the front-rear deceleration at the center of the vehicle body is not obtained. If there is, after obtaining the left / right deceleration ratio, monitor whether the left / right deceleration ratio has been used to determine soft crash, and if not used, reacquire the left / right deceleration ratio, and if a soft crash actually occurs In the case of occurrence, a soft crash determination is made using the left-right deceleration ratio and the first maximum value and the maximum value front-rear ratio of the front-rear deceleration at the center of the vehicle body acquired based on the same impact. is there. This monitoring is performed, for example, based on whether or not the state in which the soft crash determination is not performed after the acquisition of the left / right deceleration ratio continues for the set time. For example, in the case of a soft crash, the set time is set to a time slightly longer than the time from when the left / right deceleration ratio is obtained to when the first maximum value of the longitudinal deceleration at the center of the vehicle body is obtained.

In the embodiments shown in FIGS. 16 and 17, the first maximum value may be detected in the same manner as the acquisition of the first maximum value in the embodiments shown in FIGS.

Further, in each of the above embodiments, the front sensors 34 and 36 are configured to output the detected value as a level. It may be a sensor supplied to a computer.

Further, in the smoothing means for smoothing the detection values of the floor sensor 32 and the front sensors 4 and 36, the Kalman filter may be constituted by a digital filter realized by software.

In each of the above embodiments, an airbag device having an airbag as an occupant protection mechanism has been described as an example. However, a plurality of types of occupant protection mechanisms having different occupant protection functions are provided. It is also possible to apply the present invention to an occupant protection device. The plurality of occupant protection mechanisms may be selectively activated based on detection of another form of collision such as a soft crash or a head-on collision, or may be entirely activated. When all are operated, they may be operated at the same time, or may be operated at different times.
The occupant protection mechanism other than the airbag includes, for example, a pretension mechanism of a seat belt device with a pretensioner,
There is an automatic door lock release mechanism and the like. The seatbelt device with a pretensioner includes a seatbelt, a seatbelt winding device, a pretensioner, an inflator, and the like, of which the pretensioner and the inflator constitute a pretension mechanism. The pretensioner includes a clutch provided between the seat belt winding shaft and the cylinder, and prevents the driving force of the cylinder from being transmitted to the seat belt winding shaft when not in operation. When an impact exceeding a specified level occurs due to the collision, the inflator is ignited, generating high-pressure gas and moving the piston of the cylinder, whereby the clutch transmits the driving force of the cylinder to the seat belt winding shaft, and the seat belt The winding shaft is rotated to wind up the seat belt and restrain the occupant. The automatic door lock release mechanism is a mechanism for automatically releasing the automatic door lock device when a collision occurs. The use of a plurality of types of occupant protection mechanisms depends on the type of collision, the traveling speed of the vehicle, the magnitude of the impact, the relative movement speed of the occupant with respect to the vehicle (integration of the deceleration of the vehicle), and the like. For example, when the traveling speed of the vehicle at the time of the collision is low, the pretension mechanism is operated, and when it is high, the airbag is activated. The traveling speed may be the speed of the vehicle itself on which the occupant protection device operates, or may be the relative speed with respect to the collision object. Further, the pretension mechanism is operated first when the impact at the time of the collision is relatively small, and when the impact becomes larger, the airbag is also operated. A threshold value for operation determination may be set according to the type of the occupant protection mechanism.

Further, the detection of a soft crash and the determination of the operation of the occupant protection mechanism, and the detection of a collision other than the soft crash such as a head-on collision and the determination of the operation of the occupant protection mechanism are performed by independent electronic control units. It may be. In this case, the occupant protection mechanism, such as an airbag, is operated in accordance with an instruction issued early from among instructions issued from the two electronic control units.

Further, the soft crash detection method and apparatus according to the present invention are for an occupant protection device including an occupant protection mechanism other than an airbag, such as a seat belt device with a pretensioner, together with or instead of the airbag. May be used for detecting a soft crash, and may be implemented and provided in a device that needs to detect a soft crash other than the occupant protection device.

Although some embodiments of the present invention have been described above in detail, these are merely examples, and the present invention is not limited to the above-mentioned [Problems to be Solved by the Invention, Means for Solving Problems and Effects]. The present invention can be implemented in various modified and improved forms based on the knowledge of those skilled in the art, including the described embodiments.

[Brief description of the drawings]

FIG. 1 is a block diagram schematically showing an airbag device including a soft crash detection device according to an embodiment of the present invention.

FIG. 2 is a plan view showing a vehicle provided with the airbag device.

FIG. 3 is a flowchart showing a main routine stored in a ROM of a microcomputer constituting the electronic control unit of the airbag device.

FIG. 4 is a flowchart showing a soft crash detection routine constituting the main routine.

FIG. 5 is a flowchart showing a routine for obtaining a maximum value / minimum value of the deceleration of the vehicle body center, which constitutes the soft crash detection routine.

FIG. 6 is a flowchart showing a part of a left / right deceleration ratio acquisition routine stored in a ROM of the soft crash detection routine.

FIG. 7 is a flowchart showing the rest of the left / right deceleration ratio acquisition routine.

FIG. 8 is a flowchart illustrating a soft crash determination routine that constitutes the soft crash detection routine.

FIG. 9 is a block diagram schematically showing a portion of the RAM of the microcomputer which is deeply relevant to the present invention.

FIG. 10 is a graph showing detection values of a floor sensor and left and right front sensors during a soft crash.

FIG. 11 is a graph showing a change in the longitudinal deceleration at the center of the vehicle body during a soft crash together with a change in the longitudinal deceleration at the center of the vehicle body when an impact occurs due to a bad road.

FIG. 12 is a flowchart showing a part of a routine for acquiring a maximum value, a minimum value, and the like of a deceleration maximum value at a vehicle body center portion stored in a ROM of a microcomputer constituting an electronic control unit of an airbag apparatus according to another embodiment of the present invention. It is.

13 is a flowchart illustrating the rest of the routine for acquiring the maximum value / minimum value of the vehicle body center deceleration shown in FIG. 12;

14 is a block diagram schematically showing a portion of the RAM of the microcomputer having the ROM in which the routine shown in FIG. 12 is stored, which is deeply relevant to the present invention.

FIG. 15 is a diagram illustrating acquisition of a first maximum value and calculation of a deceleration average value performed by the routine shown in FIG. 12;

FIG. 16 is a flowchart showing a part of a left / right deceleration ratio acquisition routine stored in a ROM of a microcomputer constituting an electronic control unit of an airbag apparatus according to another embodiment of the present invention.

17 is a flowchart showing the rest of the left / right deceleration ratio acquisition routine shown in FIG.

FIG. 18 is a flowchart showing a left / right deceleration ratio acquisition routine stored in a ROM of a microcomputer constituting an electronic control unit of an airbag apparatus according to another embodiment of the present invention.

[Explanation of symbols]

10: Airbag device 12: Electronic control unit
14: airbag 16: microcomputer 32: floor sensor
34, 36: Front sensor 44: Inflator 48: Ignition device

Claims (2)

[Claims] At least a first maximum value of a longitudinal deceleration of a vehicle body center portion based on a detection value of a main sensor arranged near a driver's seat of a vehicle body is larger than a first maximum deceleration value. A first condition that is large and smaller than a second set deceleration, and an average value of the deceleration in the front-rear direction of the vehicle body center portion based on the detection of the main sensor up to the first maximum value, Based on a second condition that a front-to-back ratio of a maximum value obtained by dividing an average value up to a first minimum value, which is a minimum value, is smaller than a first set ratio, and a detection value of a sub-sensor disposed on each of front left and right portions of the vehicle body. All three conditions, that is, the third condition that the left-right ratio obtained by dividing the smaller front-rear deceleration by the larger front-rear deceleration among the front-rear decelerations at the left and right front portions of the vehicle body are larger than the second set ratio, are satisfied. A soft crash will occur A soft crash detection method, characterized in that: 2. A vehicle body center deceleration obtaining means for obtaining a front-rear deceleration of a vehicle body center portion in which an output of a main sensor disposed near a driver's seat of the vehicle body is smoothed, and a vehicle body center deceleration. First maximum value acquisition means for acquiring a first maximum value which is the first maximum value of the longitudinal deceleration of the vehicle body central part acquired by the acquisition means, and vehicle body center acquired by the vehicle body central part deceleration acquisition means The average value of the longitudinal deceleration of the part up to the first local maximum value and the average value from the first local maximum value to the first local minimum value of the longitudinal deceleration of the central part of the vehicle body, which is the first local minimum value, are obtained. Left and right front deceleration obtaining means for obtaining the front and rear deceleration of the left and right front parts of the vehicle body in which the outputs of the sub-sensors respectively disposed on the left and right front parts of the vehicle body are smoothed. The first maximum value is the first set deceleration. Large, the first condition that less than a second set deceleration,
The maximum value front-rear ratio obtained by dividing the average value from the first maximum value to the first minimum value by the average value of the deceleration in the front-rear direction of the vehicle body center portion up to the first maximum value is smaller than the first set ratio. And the left-right ratio obtained by dividing the smaller front-rear deceleration by the larger front-rear deceleration among the front-rear decelerations of the vehicle left-right front obtained by the left-right front deceleration obtaining means. With the third condition that is larger than the second set ratio.
A determination unit that determines that a soft crash has occurred when all of the conditions are satisfied.