JPH07165004A - Collision judging device for vehicle - Google Patents

Abstract

PURPOSE:To prevent air bag expansion against non-head-in collision. CONSTITUTION:Acceleration applied to a vehicle is three-dimensionally detected by an acceleration sensor 12. Functional value showing the magnitude of the acceleration in a vehicle traveling direction is judged as a threshold value and an air bag expansion signal is outputted by an air bag expansion circuit 19 simultaneously with collision judgements. However, air bag expansion is prevented by setting the theeshold value for the collision judgement to a higher value when the functional value of angles thetan, thetas showing the acceleration direction is judged as a threshold by an undercarriage collision detecting circuit 20 and a lateral collision detecting circuit 21 so as to be judged as the non-head- on collision. Hereby, when the undercarriage collision or the laterial collision occures, the careless air bag expansion is prevented so that any waste concerning time and expeuse for the propose of recharging the air bag, may be eliminated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle collision determination device in which an airbag is prevented from being inflated during a non-frontal collision.

[0002]

2. Description of the Related Art In order to reduce fatal accidents of occupants due to vehicle collisions, it is urgent to introduce an air bag device for protecting a driver or a driving assistant sitting in a front seat from a collision impact.
For example, in the airbag device on the driver's side, the airbag is embedded in the central portion of the steering wheel of the vehicle,
When the vehicle receives an impact exceeding a certain limit due to a collision, an impact sensor that closes the contact emits a deployment signal, and an operating current is applied to a detonator called a squib to explode the airbag. , The deployed airbag acts as a buffer between the steering wheel and the driver. However, this type of conventional airbag device uses an impact sensor that mechanically closes the contacts in response to an impact force, so that, for example, the impact received when the vehicle travels on a bad road, or There is a high possibility that the impact sensor will malfunction due to the impact received when riding on the curb, and in addition, in the case where the utility pole falls into a part of the vehicle body when the vehicle collides with the utility pole, etc.
Since the impact sensor may not operate because the collision occurs relatively slowly, there is a drawback that reliability of the operation of the impact sensor is low.

Therefore, in order to make a collision determination more reliably,
For example, as in the vehicle collision determination device 1 shown in FIG. 7, there has been proposed a device that temporally integrates the output of the acceleration sensor 2 attached to the vehicle and determines a collision when the integrated value exceeds a safety limit. Vehicle collision determination device 1 shown in FIG.
Sends the acceleration signal detected by the acceleration sensor 2 to the amplifier circuit 4 via the high-pass filtering circuit 3, and limits the amplitude of the acceleration signal G (t) amplified by the amplifier circuit 4 by the limiter circuit 5 and then offsets it. It is supplied to the integrator 6 to perform offset integration. The offset integrator 6 is
The maximum value of the acceleration signal generated during normal traveling is set as the offset Gs, and the offset G is calculated from the acceleration signal G (t).
The value obtained by subtracting s is time-integrated [G (t) -Gs] dt. The integrated output of the offset integrator 6 is supplied to the comparator 7 and compared with the threshold value Er. When the integrated output exceeds the threshold value, it is determined that a collision occurs, and a deployment signal for the airbag is output. It was supposed to be.

[0004]

A conventional vehicle collision determination device 1 is provided with a one-dimensional acceleration sensor 2 for detecting an acceleration from a specific direction, the directivity being aligned with the traveling direction of the vehicle. The one-dimensional acceleration sensor 2 has a structure in which the airbag is deployed in response to an impact from a frontal collision.
The directivity may not match the traveling direction depending on the mounting position or mounting posture, and especially when mounted on a vehicle with insufficient vehicle body rigidity, for example, underside where the road surface rubs against the underside of a vehicle other than head-on collision. The airbag may be deployed even in the event of a carriage collision or a side collision in which another vehicle or the like collides with the side surface of the vehicle body. Normal,
The airbag is designed to effectively protect the occupant against the impact of a frontal collision, so that an undercarriage collision that impacts the occupant from the bottom to the top and a side impact to the occupant from the side. With regard to collisions, occupant restraints such as seat belts are better in terms of protection from impacts, so if you inadvertently deploy an airbag, you can deploy the airbag once it has been deployed. However, there is a problem in that the user must be replaced with a new air bag, which imposes a burden on the user in terms of time or cost.

Further, an apparatus adopting a structure for switching a threshold value for collision determination according to a driving state of a vehicle is disclosed in Japanese Utility Model Laid-Open No. 4-119760, "Airbag device for automobile". To determine the collision, it is determined that the object is slipping from the slip rate of the wheels, the vehicle height is lower than during normal driving, or when a sudden steering wheel operation is performed. However, the airbag is not controlled to be deployed according to the direction of the impact associated with the collision, so the airbag may be inadvertently deployed due to an undercarriage collision or a side collision. There was a problem such as. Also, a device configured to execute a plurality of different algorithms in parallel for the same acceleration data and judge a collision by a majority verdict uses a multiple collision evaluation algorithm for passenger restraint system and evaluation expertise. Device and method ", which is configured to perform multiple collision evaluation using a velocity algorithm, a displacement algorithm, or a rapid motion algorithm for collision determination, and can clearly distinguish frontal collisions from non-frontal collisions. It wasn't something.

Further, the above-mentioned conventional vehicle collision determination device 1
Has a configuration in which the offset integrator 6 time-integrates the acceleration signal G (t), it takes time to obtain an integration result, and therefore, the expansion signal is required when it is necessary to instantly determine a collision. There was a problem that it was easy to be delayed. If it is assumed that the time required to deploy the airbag is 30 ms when the vehicle is traveling at medium speed or high speed, the occupant who leans forward due to the impact of the collision is 12.5 cm. In order to ideally design the fully deployed airbag to catch the occupant when leaning forward,
The period from the actual collision to the collision judgment is limited to a very short time, and due to the delay in the collision judgment, the airbag cannot be deployed in time and a satisfactory cushioning effect can be obtained. In some cases, it was not possible. Also,
The speed change amount obtained from the offset integrator 6 is useful for collision determination in the case where a significant change occurs before and after the collision, but is bad when the vehicle relatively slowly stops, for example, when the vehicle collides with a utility pole. It is not rare to be able to distinguish it from the case of traveling on the road.Therefore, the airbag does not operate during a pole collision, but the airbag operates when driving on a bad road such as a mountain road. It had problems such as lack of quality.

[0007]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and is an acceleration detecting means for detecting the magnitude and direction of acceleration applied to a vehicle, and the magnitude of acceleration detected by the acceleration detecting means. Alternatively, a non-frontal collision is performed by performing a threshold value determination on the function value thereof, and by performing threshold value determination on the collision determination means for outputting an airbag deployment signal together with the collision determination and the direction of the acceleration detected by the acceleration detection means or the function value thereof. When it is recognized that the collision determination means is provided, a collision determination regulation means for regulating the collision determination by the collision determination means is provided.

The present invention further includes a three-dimensional acceleration sensor for detecting the acceleration applied to the vehicle by dividing the acceleration into a basic axis along the traveling direction of the vehicle and a total of three axial components of two axes perpendicular to the vertical and horizontal directions of the basic axis. Among the outputs of the three-dimensional acceleration sensor, the acceleration component in the basic axis direction or the function value thereof is determined by a threshold value,
A collision determination means that outputs an airbag deployment signal together with the collision determination, and a threshold determination of the direction of the acceleration or a function value thereof from the output of the three-dimensional acceleration sensor, and the collision when it is recognized as a non-frontal collision. The determination means is provided with a collision determination regulation means that regulates the collision determination by setting the threshold value used for the collision determination higher by a fixed time interval.

[0009]

According to the present invention, the magnitude and direction of acceleration applied to a vehicle are detected, the magnitude of acceleration or its function value is discriminated by a threshold value, an airbag deployment signal is output together with a collision determination, and the direction of acceleration is determined. Alternatively, when the function value is discriminated as a threshold value, and when it is recognized that the collision is not a frontal collision, the threshold value used for the collision determination by the collision determination means is set higher by a certain time interval to regulate the collision determination. As a result, the airbag is prevented from being inadvertently deployed against a non-frontal collision such as an undercarriage collision or a side collision.

[0010]

Embodiments of the present invention will be described below with reference to FIGS. FIG. 1 is a circuit configuration diagram showing an embodiment of a vehicle collision determination device of the present invention, FIG. 2 is a diagram showing a collision determination map used in the expansion trigger circuit shown in FIG. 1, and FIGS. 6 is a flowchart for explaining operations of an undercarriage collision detection circuit and a side collision detection circuit shown in FIG. 1.

The vehicle collision determination device 11 shown in FIG. 1 uses a three-dimensional acceleration sensor 12 that decomposes and detects the acceleration applied to the vehicle for each component in the three-dimensional direction. Carriage collisions and side collisions are configured to be clearly distinguished from other collisions. The three-dimensional acceleration sensor 12 has a total of three X-axis (base axis) along the traveling direction and two axes Y and Z orthogonal to the X-axis (base axis).
Three detection elements 12x, 12 having sharp directivity on the axis
y, 12z are integrally assembled, and traveling direction acceleration α output by each of the detection elements 12x, 12y, 12z
x, the vertical acceleration αy, and the horizontal acceleration αz, the traveling acceleration αx is used for collision determination, and the angle θu formed by the traveling acceleration αx and the vertical acceleration αy and the traveling acceleration αx and the lateral direction are used for restricting the expansion. Acceleration α
The angle θs formed by z is used.

In order to determine a collision requiring deployment of the airbag, that is, a front collision such as a medium speed frontal collision, a high speed frontal collision, a cushion drum collision or a pole collision, the acceleration sensor 12 of the embodiment is used. Among the outputs, the acceleration αx along the traveling direction is calculated, and the collision determination is made by the binary threshold determination. That is, the acceleration αx output from the acceleration sensor 12 is first band-limited in the low-pass filter circuit 13 for eliminating the influence of aliasing distortion before being converted into discrete value data, and then operated in synchronization with the sampling clock. It is supplied to the AD converter 15 via the open / close switch 14 and is converted into digital data with a predetermined quantized bit. The acceleration data G (k) obtained from the AD converter 15 is simultaneously subjected to offset integration and impact force calculation, and the speed change amount and impact force required for binary determination are calculated.

The offset integration is performed by the speed change amount calculation circuit 16 of the successive addition type, and the offset data Go representing the maximum value of the acceleration signal generated during normal running is subtracted from the discretely valued acceleration data G (k). This is done by adding the values according to the sampling clock. That is, the speed change amount ΔV (k) obtained by the offset integration is obtained as ΔV (k) = Σ [G (k) −Go]. For this reason, the maximum value of the acceleration applied to the vehicle during normal traveling can be excluded from the integration target as an offset, and the speed change amount may continue to accumulate due to vibration received from a bad road during normal traveling, or It is possible to eliminate, over a considerable range, a factor that is likely to make the collision determination erratic, such as an abrupt change in speed when the vehicle rides on a curb. Further, since the steady error that the acceleration sensor 12 itself has as an individual difference can be included in the offset, it is possible to compensate the operation of the measurement system at the same time.

On the other hand, the impact force calculation is first performed by the band-pass filter circuit 1.
40 from 100Hz included in the acceleration data
It is performed by extracting a band component of 0 Hz and performing a square calculation in the subsequent impact force calculation circuit 18. Here, regarding a plastic collision in which the occupant is injured when the vehicle collides, the front part of the vehicle is regarded as a plastic spring that is composed of innumerable spring bodies, and the acceleration signal of the acceleration signal From various vibration waveforms superimposed on the basic 1/4 sine wave, it is possible to extract a specific band component exhibiting a remarkable change at the time of collision. That is, 100 of the acceleration data
The band components from Hz to 400 Hz show a frequency distribution peculiar to each vehicle type, but it is known that they show a large change depending on the severity of the collision, that is, the magnitude of the impact. Therefore, pay attention to these band components. Thus, it is possible to detect an impact force that cannot be understood only by tracking the speed change amount.
Further, since the impact force calculation circuit 18 squares the above-mentioned band component that changes between positive and negative, it is possible to accurately grasp the magnitude of the impact force regardless of whether the acceleration is positive or negative. At 19, it is possible to determine that the collision requires an airbag operation, in distinction from an impact or the like associated with an undercarriage collision or a side collision.

The offset integration output and the impact force calculation output are
It is supplied to the expansion trigger circuit 19 and subjected to collision determination according to the collision determination map shown in FIG. The expansion trigger circuit 19 shown in the embodiment has an impact force ΔE (k) and a speed change amount Δ.
The collision determination is performed with a determination curve that divides the collision area and the non-collision area as a boundary on a plane having V (k) as two axes. That is, the expansion trigger circuit 19 determines the impact force ΔE (k) and the speed change amount ΔV.
First, using (k) as a parameter (parameter),

[0016]

[Equation 1]

Then, the arithmetic result is

[0018]

[Equation 2]

A collision is determined when the following relation is satisfied, and the entire circuit is composed of an arithmetic operation circuit. In addition,
The parameters p, q, and r in the equation are coefficients of a determination curve that is approximated to an ellipse on a collision determination map having impact force ΔE (k) and speed change amount ΔV (k) as two axes, and are values unique to the vehicle type. Therefore, it is possible to empirically obtain the optimum value by repeating the collision test for each vehicle type.

In the collision determination map shown in FIG. 2, in addition to a frontal collision at a medium speed and a frontal collision at a high speed, a collision with a cushion drum made of a can-like body having a cushioning function, a utility pole, a pole, etc. In each case such as a collision with a pole, the regions where the correlation between the impact force ΔE (k) and the speed change amount ΔV (k) is deepest are shown by enclosing each with a dotted line. Further, in the region inside the determination curve, the expansion trigger circuit 19 such as an undercarriage collision indicating a normal running or a road surface thrust up against the floor surface of the vehicle body or a side surface collision indicating a vehicle body side surface collision.
The impact force ΔE
Regions where the correlation between (k) and the amount of change in speed ΔV (k) is deepest are shown surrounded by dotted lines. These classification patterns were created based on the data obtained when a collision test was actually conducted using a vehicle, and the impact force ΔE
If (k) and the amount of change in speed ΔV (k) are known, it is possible to clearly distinguish between collision and non-collision with the judgment curve as a boundary.

The above-mentioned judgment curve dividing the collision area and the non-collision area on the collision judgment map is peculiar to the vehicle type.
In order to clearly distinguish between a frontal collision and a non-frontal collision, only when a non-frontal collision is specified here, the determination curve is determined by the output of the undercarriage collision detection circuit 20 or the side collision detection circuit 21 described later. Is moved to the collision area side for a certain period of time to set a high threshold value for collision determination so that the airbag is not inflated due to such a non-frontal collision. Specifically, the detection of the non-frontal collision is performed by the detection element 1 that constitutes the three-dimensional acceleration sensor 12.
This is performed by calculating the acceleration directions on the XY plane and the XZ plane based on the outputs αx, αy, and αz of 2x, 12y, and 12z. The undercarriage collision detection circuit 20 also detects the side collision. The circuit 21 has the same basic operation principle except that the detection target is different, and there are some parameters used for the calculation performed on the vertical angle θu of the acceleration with respect to the vehicle traveling direction and the horizontal angle θs of the acceleration with respect to the vehicle traveling direction. Since they are different, the undercarriage collision detection circuit 20 will be described here as an example with reference to the flowchart shown in FIG.

The undercarriage collision detection circuit 20
First, in step (101) shown in FIG. 3, of the outputs αx, αy, αz of the three-dimensional acceleration sensor 12, αx, α
Using y, the arctangent | αy / αx | is calculated, and the vertical angle θu of the acceleration with respect to the vehicle traveling direction on the XY plane is calculated. Next, in order to reflect the absolute value of the acceleration in the collision determination, in the following step (102), the following cases are divided, and the angle θu is corrected according to the magnitude of the absolute value of the acceleration, so that the corrected angle θu '
To get That is, if | αx | <a and | αy | <b, then in step (103), θu ′ = 0, and | αx
| ≧ a, and | αy | ≧ b, and | αx | + | αy | <
If c, then in step (104), θu ′ = θu · f (α
x, αy), and | αx | ≧ a, | αy | ≧ b, and | αx | + | αy | ≧ c, θu ′ = θu is set in step (105).

As f (αx, αy), for example, the square root of the sum of absolute values | αx | and | αy | is used.
It is also possible to use the natural logarithm of αx | + | αy |, or the square root of the sum of squares of αx and αy. In short, the magnitude of the correction angle θu ′ is calculated by using the absolute values of acceleration | αx |, | α
Any function may be used as long as the correction is such that the larger y |

After correcting the angle θu in consideration of the absolute value of the acceleration in this way, in the subsequent step (106), the correction angle θu ′ is low-pass filtered to eliminate the middle-range or high-range component. As the cutoff frequency of this low-pass filtering, it is preferable to use an optimum frequency calculated from the empirical value obtained by repeating the running test and the collision test using an actual vehicle. Note that, instead of the low-pass filtering, it is also possible to use, for example, interval integration of several samples, and in some cases, mid-pass filtering or high-pass filtering may be used. When it is scarce, the step (106) can be omitted.

The angle θu "obtained by low-pass filtering from the correction angle θu 'is used for the first time in step (107) for threshold value discrimination according to the magnitude relationship with the angle θr serving as a comparison reference. In that case, the angle θu ”is the angle θ
If it is less than r, the process returns to step (101), but if the angle θu ″ exceeds the angle θr, it is recognized as an undercarriage collision in the following step (108), and the expansion trigger circuit 19 immediately determines the collision. That is, the judgment curve, which is the boundary line that divides the collision area and the non-collision area on the collision judgment map, is moved to the collision area side from the alternate long and short dash line to the solid line position shown in FIG.
This movement of the judgment curve needs to be limited to a predetermined time specified in advance. Therefore, in the subsequent judgment step (109), when it is found that a predetermined time has elapsed from the movement of the curve, the judgment curve is judged in step (110). Restore the curve to the non-collision zone side.

In this way, when the undercarriage collision detection circuit 20 specifies that the collision is an undercarriage collision, the undercarriage collision is moved in order to move the judgment curve to the collision area side for a certain period of time and tighten the collision judgment conditions. It is possible to avoid the airbag deployment due to the undercarriage collision as much as the determination curve moves away from the area of. If you turn the inside out, it is clear that the collision is not an undercarriage collision.By keeping the judgment curve moving to the non-collision area side, you can make a medium-speed or high-speed frontal collision or a cushion drum collision. It is possible to expand the collision area for pole and pole collisions, and when an undercarriage collision occurs, move the collision curve to the collision area side to narrow the collision area and inadvertently deploy the airbag. You can prevent it.

As with the undercarriage collision detection circuit 20, the side collision detection circuit 21 also detects a side collision according to steps (201) to (210) shown in FIG. 4 and identifies the collision as a side collision. At this time, the judgment curve can be moved to the collision area side for a fixed time, and the collision judgment condition can be made stricter.

As described above, according to the vehicle collision determination device 11, the collision determination by the collision determination means is regulated when the non-frontal collision is recognized, so that the deployment of the airbag is effective for protecting the occupant. It is possible to prevent the airbag from being inadvertently expanded when an undercarriage collision or a side collision occurs, instead of a frontal collision, and the airbag is expanded against a collision that originally does not need to be expanded. It is possible to eliminate time or cost waste for replacing the deployed airbag and reloading a new one.

Since the acceleration applied to the vehicle is detected by the three-dimensional acceleration sensor 12 which detects the acceleration in the traveling direction and the two axes orthogonal to the traveling direction, the undercarriage collision is detected in the traveling direction of the vehicle. This can be detected by calculating the angle θu formed between the acceleration and the vertical acceleration, and in the case of a side collision, the angle θs formed between the acceleration in the vehicle traveling direction and the lateral acceleration.
Can be calculated and detected. In that case, regarding the angle data that does not have a large acceleration, it can be excluded from the undercarriage collision detection or the side collision detection because it is caused by the impact received from the road surface as the vehicle travels, and it is accompanied by the size and the vehicle progress. When a frontal collision occurs in which the airbag must be inflated by certifying that it is a non-frontal collision that restricts airbag deployment only when acceleration that exceeds a certain angle with respect to the direction occurs. In addition, it is possible to prevent the collision determination from being accidentally restricted.

Further, by considering the front portion of the vehicle as a plastic spring in which a myriad of spring bodies are compounded, various vibration waveforms superimposed on the fundamental 1/4 sine wave of the acceleration signal in the process of stopping the vehicle due to a collision. Among them, it is possible to detect an impact force that cannot be understood only by extracting a remarkable specific band component at the time of collision and tracking the amount of change in velocity. From the force, it is determined that it is a collision that requires the operation of the airbag, distinguishing it from the impact caused by running on a bad road or riding on a curb, etc. In addition, it is possible to determine a collision with high accuracy.

Further, the impact force ΔE (k) and the speed change amount ΔV
Since the expansion trigger circuit 19 is used to make a collision determination on the boundary of a curve that divides the collision area and the non-collision area on a plane having (k) as two axes, the impact force ΔE (k) and the speed change amount ΔV (k ) Is given arithmetically when they are given a function, and the collision can be determined by whether the calculation result is inside or outside the curve that divides the collision area and the non-collision area. Even if the decision curve is different, it can be handled by simply replacing the function, so it has excellent versatility, and for frontal collisions that are clearly not undercarriage collisions or side collisions. ,
The threshold value can be moved to the non-collision area side and can be surely tied to the deployment of the airbag.On the other hand, when an undercarriage collision or a side collision occurs, the threshold value can be moved to the collision area side. It is possible to prevent the deployment of airbags.

In the above embodiment, the undercarriage collision detection circuit 20 has been described as one unit that sequentially executes a plurality of arithmetic operations, but, for example, FIG.
Like the undercarriage collision detection circuit 30 shown in
Angle calculation circuit 31 for calculating the vertical angle θu of acceleration
And an angle correction circuit 32 that corrects the angle θu according to the magnitude of the acceleration, a filter circuit 33 that low-pass filters the corrected angle θu ′, and an angle θu ″ output from the filter circuit 33 is compared with the angle θr. It is also possible to connect in series a comparator circuit 35 or the like that determines the threshold value and moves the determination curve for a fixed time set in the timer circuit 34. Further, a change to the same type of circuit configuration is possible. Side collision detection circuit 21
Is similarly possible.

Further, in the above-mentioned embodiment, the judgment curve which divides the collision area and the non-collision area on the collision judgment map can be approximated by not only an ellipse but also a circle or a hyperbola or a complex curve of the third order or more. Yes, for example, as shown in FIG. 6, it can be approximated by three straight lines. In this case, the non-collision area is surrounded by three straight lines, and the inequality of ΔE (k) <g ΔV (k) <h (ΔE (k) / i) + (ΔV (k) / j) <1 The area to be filled is the non-collision area.

Further, in the above embodiment, the expansion trigger circuit 1
9 was configured using an arithmetic operation circuit, but in addition to this,
For example, it can be configured by a memory that stores collision determination data using the impact force ΔE (k), the speed change amount ΔV (k), and the collision angles θu and θs as addresses, and a circuit that controls the reading of this memory. For example, it is possible to instantly make a collision determination using a ROMized lookup table or the like, and by preparing a ROM for each vehicle type,
A wide range of support is possible.

[0035]

As described above, according to the present invention, the magnitude and direction of the acceleration applied to the vehicle are detected, the magnitude of the acceleration or its function value is discriminated by the threshold value, and the airbag deployment signal is detected together with the collision determination. Is output, and the direction of acceleration or its function value is discriminated by a threshold value, and the collision judgment by the collision judgment means is regulated when a non-frontal collision is recognized. It is possible to prevent the airbag from being inadvertently expanded when an undercarriage collision or a side collision occurs, instead of a frontal collision that is effective for protection. Also, it is possible to eliminate the waste of time or cost for reloading the airbag again.

Further, according to the present invention, the acceleration detecting means is composed of a multi-dimensional acceleration sensor for detecting the acceleration applied to the vehicle by dividing the acceleration into at least two axial directions of the traveling direction and the direction orthogonal to the traveling direction. In the case of an undercarriage collision, a vehicle whose acceleration can be detected in two directions, that is, the vehicle traveling direction and the direction perpendicular to the vehicle traveling vertically, is used. In the case of a side collision, the vehicle traveling direction and the direction orthogonal to the left and right are used. By using a three-dimensional acceleration sensor that can detect acceleration in the direction and also has the functions of both, it is possible to reliably detect non-frontal collisions such as undercarriage collisions and side collisions that should regulate the deployment of the airbag. There is an effect such as being able to.

Further, according to the present invention, the collision determination means calculates the speed change amount by integrating the acceleration applied to the vehicle with respect to time, and extracts a specific band component which is included in the acceleration and which remarkably appears at the time of a vehicle collision. Since the impact force is calculated by squaring the vehicle and the collision determination is performed using the impact force and the amount of speed change as parameters, the front part of the vehicle can be checked for a plastic collision that may injure the occupants when the vehicle collides. By considering it as a plastic spring that is composed of innumerable spring bodies, among the various vibration waveforms that are superimposed on the basic 1/4 sine wave of the acceleration signal during the process of stopping the vehicle due to the collision, a particular By extracting the band component, it is possible to detect the impact force that cannot be understood only by tracking the speed change amount. Therefore, from the impact force obtained by squaring the specific band component that appears in both positive and negative directions, the rough road can be run. High-speed and highly-accurate collision judgment is performed by distinguishing from a shock or the like caused by riding on a curb, etc. to determine that the collision requires airbag deployment, and comprehensively judging the collision together with the amount of speed change. It is possible to achieve such effects.

Further, according to the present invention, the collision determination regulating means is
The angle data indicating the direction of the acceleration detected by the acceleration detection means is adopted only when the magnitude of the acceleration giving the angle data exceeds a certain value, and the adopted angle data has a predetermined threshold for the non-frontal collision side. When the value exceeds the value, it is determined that it is a non-frontal collision.Therefore, regarding angle data that does not have a large acceleration, it is determined that an undercarriage collision judgment or side It can be excluded from collision judgment, and it is certified as a non-frontal collision that restricts airbag deployment only when acceleration with a magnitude and in a direction exceeding a certain angle with respect to the vehicle traveling direction occurs. , In order to prevent accidental restriction of collision judgment when a frontal collision occurs where the airbag must be deployed. The effect of such kill.

Furthermore, according to the present invention, the acceleration component along the vehicle traveling direction or the function value thereof in the output of the three-dimensional acceleration sensor is discriminated by a threshold value, the airbag deployment signal is output together with the collision determination, and the three-dimensional acceleration signal is output. The direction of acceleration or its function value is discriminated from the output of the acceleration sensor by a threshold value, and the threshold value used for collision judgment when it is recognized as a non-frontal collision is set higher by a certain time interval to make the collision judgment. Due to the regulation, the collision area and the non-collision area defined by the threshold value that is the criterion for collision judgment are used for frontal collisions that are clearly not undercarriage collisions or side collisions. The threshold value can be moved to the non-collision area side so that it can be surely linked to the deployment of the airbag, while undercarriage collision or side collision occurred. Can has an effect such as can be made to not reach the air bag deployment by moving the threshold to the collision frequency side.

Further, according to the present invention, the collision judgment is made on the basis of the judgment curve which divides the collision area and the non-collision area on the collision judgment map having the two axes of the impact force and the velocity change amount, and the undercarriage collision or the side surface When it is possible to identify a collision, the judgment curve is moved to the collision area side for a certain time to regulate the collision judgment. There is an effect that the airbag can be deployed and the airbag can be always undeployed in the case of a non-frontal collision.

[Brief description of drawings]

FIG. 1 is a circuit configuration diagram showing an embodiment of a vehicle collision determination device of the present invention.

FIG. 2 is a diagram showing a collision determination map used in the expansion trigger circuit shown in FIG.

3 is a flowchart for explaining the operation of the undercarriage collision detection circuit shown in FIG.

FIG. 4 is a flowchart for explaining the operation of the side collision detection circuit shown in FIG.

FIG. 5 is a circuit configuration diagram showing another embodiment of the undercarriage collision detection circuit.

6 is a diagram showing another embodiment of the collision determination map used in the expansion trigger circuit shown in FIG.

FIG. 7 is a circuit configuration diagram showing an example of a conventional vehicle collision determination device.

[Explanation of symbols]

11 Vehicle Collision Determination Device 12 Acceleration Detection Means (Acceleration Sensor) 15 Collision Determination Means (AD Converter) 16 Collision Determination Means (Speed Change Calculation Circuit) 17 Collision Determination Means (Band Filtering Circuit) 18 Collision Determination Means (Impact Force) Arithmetic circuit) 19 Collision determination means (deployment trigger circuit) 20, 30 Collision determination regulation means (undercarriage collision detection circuit) 21 Collision determination regulation means (side collision detection circuit) 31 Angle calculation circuit 32 Angle correction circuit 33 Filter circuit 34 Timer Circuit 35 Comparison circuit

Claims (6)

[Claims] 1. An acceleration detecting means for detecting the magnitude and direction of an acceleration applied to a vehicle, and a threshold value for the magnitude of the acceleration detected by the acceleration detecting means or a function value thereof to determine a collision and an airbag deployment. The collision determination means that outputs a signal and the direction of the acceleration detected by the acceleration detection means or a function value thereof are subjected to threshold determination, and when the collision is recognized as a non-frontal collision, the collision determination by the collision determination means is regulated. A collision determination device for a vehicle, comprising: collision determination regulation means. 2. The acceleration detecting means is a multi-dimensional acceleration sensor that detects acceleration applied to a vehicle separately in at least two axial directions of a traveling direction and a direction orthogonal to the traveling direction. 1. The vehicle collision determination device according to 1. 3. The collision determination means includes a speed change amount calculation circuit for time-integrating an acceleration component in the vehicle traveling direction output from the acceleration detection means to calculate a speed change amount, and an acceleration component in the vehicle traveling direction. A band-pass filter circuit for extracting a specific band component that appears remarkably at the time of a vehicle collision, an impact force calculation circuit for calculating the impact force by squaring the output of this band-pass filter circuit, the output of this impact force calculation circuit and the speed. 2. A deployment trigger circuit for making a collision determination by a binary threshold value determination based on the output of the change amount calculation circuit and outputting a deployment trigger signal for the airbag.
The vehicle collision determination device described. 4. The collision determination regulation means adopts and adopts the angle data indicating the direction of the acceleration detected by the acceleration detection means only when the magnitude of the acceleration giving the angle data exceeds a certain value. 2. The vehicle collision determination device according to claim 1, wherein when the angle data exceeds a predetermined threshold value on the non-frontal collision side, the non-frontal collision is identified. 5. A three-dimensional acceleration sensor for detecting the acceleration applied to the vehicle by dividing it into a basic axis along the traveling direction of the vehicle and a total of three axial components of two axes orthogonal to the vertical and horizontal directions of the basic axis, and the three-dimensional acceleration sensor. Of the output of the acceleration component of the basic axis direction or a function value thereof is determined by a threshold value, and collision determination means for outputting an airbag deployment signal together with collision determination, and the direction of the acceleration from the output of the three-dimensional acceleration sensor or its Collision determination regulation for discriminating a collision by setting the threshold value used for the collision determination by the collision determination means to a higher value by a certain time interval when the function value is determined by a threshold value and it is recognized as a non-frontal collision. And a vehicle collision determination device. 6. The collision determination means makes a collision determination with a determination curve that divides a collision area and a non-collision area as a boundary on a collision determination map having an impact force and a speed change amount as two axes, and the collision determination regulation. 6. The vehicle collision determination device according to claim 5, wherein when determining that the collision is an undercarriage collision or a side collision, the means regulates the collision determination by moving the determination curve to the collision area side for a fixed time.