JP3289593B2 - Vehicle collision determination method and collision determination device - Google Patents

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 method and a vehicle collision determination method, in which a threshold value of an acceleration gradient amount in addition to an impact force and a speed change amount is determined as a threshold value. It relates to a determination device.

[0002]

2. Description of the Related Art In recent vehicle designs, safety at the time of a collision is particularly emphasized, and a system for operating an occupant restraint such as an airbag for protecting an occupant at the time of a collision is required to improve collision identification performance or to increase intelligence. The goal is constantly being improved. Behind the need to improve collision identification performance,
Significant progress has been made in occupant safety measures on the vehicle structure side, and when a collision is identified in the passenger compartment, a vehicle with a structure in which the impact from the collision site is less likely to be transmitted to the occupant in the early stage of the collision is a sign of the occurrence of the collision Since the time has already passed before appears, the determination condition becomes stricter than before. On the other hand, research on collision test standards assuming actual collisions has been repeated, and various types of collisions other than the standard barrier collision, for example, collision types such as a 50% offset oblique collision and an offset deformation barrier collision, have been studied. Development of a device that can quickly and accurately identify whether or not the restraint should be deployed is awaited.

[0003] A vehicle collision judging device 1 shown in FIG. 4 is a device for judging whether or not a collision should activate an occupant restraint such as an airbag at the time of a vehicle collision. This collision determination device 1 is based on the premise that regarding a plastic collision that causes harm to an occupant when the vehicle collides, the front part of the vehicle is regarded as a plastic spring in which a myriad of spring bodies are combined, and the vehicle stops due to the collision. By extracting a specific band component remarkable at the time of collision from various vibration waveforms superimposed on the basic 1/4 sine wave of the acceleration signal in the process of reaching, the impact force that cannot be understood only by tracking the speed change amount Is detected and distinguished from an impact or the like caused by running on a rough road or riding on a curb, etc., so that a collision that requires the operation of the safety device is determined. As a result of various experiments, 200 Hz to 200 Hz included in the acceleration data
It has been known that the Hz band component shows a large change according to the magnitude of the impact. Therefore, in the impact force calculation, first, the acceleration signal G obtained by the acceleration sensor 2 is converted into a low-pass filtering circuit for eliminating aliasing distortion. 3a and a high-pass filtering circuit 3b.
a and 19b as discrete value data in the digital signal processor 1a. As the acceleration sensor 2, a sensor in which a stress-strain gauge using a piezoresistance change is incorporated on a semiconductor substrate with a pressure-receiving surface facing in the traveling direction of the vehicle is used. Alternatively, a capacitance type semiconductor acceleration sensor, an acceleration sensor using a piezoelectric element, a pure mechanical acceleration sensor using an elastic spring, or the like can be applied. In the case of this example, the low-pass filtering circuit 3a removes high-frequency components exceeding 80 to 260 Hz in order to eliminate the influence of aliasing distortion, and the subsequent high-pass filtering circuit 3b removes high-frequency components from the output of the low-pass filtering circuit 3a. A low frequency component of 160 Hz or less, for example, a low frequency component of 20 Hz or less is removed.

The acceleration data taken into the digital signal processing section 1a is subjected to an impact force judgment, a short section integration judgment and a long section integration judgment, and a collision judgment is made by summing up these judgment results. First, the absolute value of the band component Gb extracted by the high-pass filtering circuit 3b is obtained by an absolute value circuit 4, and a threshold value is determined by a comparator 5 followed by a numerical value ΔE (k) representing the impact force obtained here. Is done. In general, for a speed that approximately attenuates according to a cosine curve, the impact force between two points that are very close to each other between 0 ° and 90 ° on the cosine curve is the square of the speed change between these two points. Since it can be regarded as proportional, here, the impact force is calculated by an absolute value operation substantially equivalent to a square operation. The numerical value ΔE (k) representing the impact force determined by the threshold value in the comparator 5 is shaped in the following waveform shaper 6. The waveform shaper 6 extends the output of the comparator 5 in the time axis direction for a certain period when an impact force exceeding the threshold value is obtained as the output of the comparator 5, and the waveform shaper lasts for at least a certain period. A one-shot circuit 6a that generates a one-shot pulse that is triggered by the rise of the output of the comparator 5 and lasts, for example, about 20 ms, and the output one-shot pulse of the one-shot circuit 6a and the one-shot pulse of the comparator 5 And an OR gate circuit 6b for taking a logical sum with the original output. For this reason, when the output of the absolute value circuit 4 shows a sudden change in the impact force exceeding the dangerous value, the output of the waveform shaper 6 indicates that the possibility of collision recognition is high during the duration of the one-shot pulse. Will continue to be specified.

On the other hand, the output Ga of the low-pass filtering circuit 3a is section-integrated by the section integrators 7 and 8 for the short section and the long section in order to calculate the speed change amount. The discrete-valued acceleration data Ga (k) is, for example, 18 ms by the short interval integrator 7.
And the long interval integrator 8 has, for example, 90 ms.
Are sequentially added in the integration section of. Short interval integrator 7
Is threshold-determined in the following comparators 9 and 10,
When an integral value exceeding a certain threshold value Vrs1 or Vrs2 is obtained, an active signal is output to the determination circuit 13 over the shaping time of the waveform shapers 11 and 12. 11a and 12a are one-shot circuits,
11b and 12b are OR gate circuits. Meanwhile,
The output of the short interval integrator 7 is also sent to the differentiator 14 in addition to the comparators 8 and 10, and is used for calculating the acceleration gradient amount. This is because, when a collision occurs, an acceleration is rapidly generated even in a relatively low frequency band, so that a time gradient (gradient) of this acceleration is detected by the differentiator 14 and used for collision determination. The acceleration gradient amount output from the differentiator 14 is discriminated as a threshold value based on a threshold value αr in a subsequent comparator 15, and an active signal is output from the comparator 15 when an acceleration gradient amount exceeding the threshold value αr occurs. Is output.

The output of the short interval integrator 7 changes by Ga (k) -Ga (k-T) for each sample.
The time change rate of (k) -Ga (k-T) corresponds to the time differential value of the short-range integral value. Therefore, here, the magnitude of the difference between the current acceleration data Ga (k) and the past acceleration data G (k−T) observed just before the integration interval T is determined by the comparator 15 as a threshold. Will be. For this reason, even if no remarkable change is observed between adjacent acceleration data samples, a medium-speed head-on collision in which the acceleration data shows a remarkable change between two points separated by the integration interval T occurs. In addition, a remarkable change appears in the output of the differentiator 14, and a collision can be effectively determined for an acceleration that gradually increases. However, since the time differential value of the short interval integrated output is used as a logical product of the output of the waveform shaper 12 and the collision determination as described later, for example, only the time differential value of the short interval integrated output protrudes along with the curb climbing. However, if the short-range integrated output is equal to or smaller than the threshold, no collision determination is made.

The output of the long interval integrator 8 is threshold-determined by the comparator 16 and outputs an active signal to the determination circuit 13 when an interval integral value exceeding a predetermined value Erl is obtained. The determination based on the long-range integral value is effective in determining a collision with a collision object that absorbs a large amount of collision energy, for example, a cushion drum, and unlike a high-speed barrier collision, a slow velocity is used. Therefore, the necessity of airbag deployment is determined from the integrated value accumulated over a long period of time.

The judgment circuit 13 is supplied with the threshold judgment output of the impact force, the threshold judgment output of the long-term integral value and the short-term integral value, and the threshold judgment output of the acceleration gradient amount. Is determined. That is, the determination circuit 13 is an AND gate circuit 13 a that calculates the logical product of the impact force threshold value determination output output from the waveform shaper 6 and the threshold value determination output of the short-term integral value output from the waveform shaper 11.
AND gate circuit 13b which takes the logical product of the threshold determination output of the short-term integral value output by the waveform shaper 12 and the threshold determination output of the acceleration gradient amount output by the comparator 15
And the outputs of the AND gate circuits 13a and 13b and the comparator 1
And an OR gate circuit 13c for calculating the logical sum of the long interval integrated value and the threshold value judgment output output from the OR gate 6. The active output output from the OR gate circuit 13c becomes an airbag deployment trigger signal.

Thus, the determination by the determination circuit 13 is performed by using a plane having two axes of the speed change amount ΔV (k) and the impact force ΔE (k) as shown in FIGS. 5 (A) and 5 (B). Speed change amount ΔV (k) and acceleration gradient amount ΔGr
The determination is performed in two determination areas I and II that define a collision area and a non-collision area on a plane having (k) as two axes. The collision areas I and II defined by the determination curves in each plane are: Area I; ΔV (k)> Vrs1, and ΔE (k)> Er Area II; ΔV (k)> Vrs2, and ΔGr (k)> When the condition that satisfies either one of the regions I and II is satisfied, a collision determination is made.

[0010]

The above-mentioned conventional vehicle collision judging apparatus 1 simultaneously distinguishes the characteristics of a vehicle collision that requires the operation of an occupant restraint system such as an airbag in a time zone in which a combination of various physical quantities is present. However, as the vehicle structure in which the beam and the bumper more effectively protect the occupant's living space against the impact at the time of the collision, the distance from the vehicle tip to the collision determination device 1 becomes longer. In the case of a large vehicle with a large crash zone that becomes far away and deforms and cushions in the event of a collision, about 40 ms from the start of the collision
Since the initial acceleration transmitted until the time elapses is very weak, there are cases where it is difficult to make a collision determination in the two regions of the region I or the region II, which is a collision determination requirement other than the speed change amount. In some cases, the striking force and the amount of acceleration gradient could not be clearly extracted because they were derived from the weak acceleration signal at the beginning of the collision.

A typical example is a collision at a speed (for example, 15 miles per hour) at which a deployment is triggered in a low-speed head-on collision, and a speed at which deployment is not triggered (for example, 12.5 per hour).
Miles), but both are ΔV (k) and ΔGr
On the two-dimensional plane of (k), it is actually measured to show time-dependent changes (a) and (b) with no remarkable difference as shown in FIG. 5. There is a problem that it is impossible to judge a collision by distinguishing sharply. Further, in such a low-speed frontal collision, even in the region I defined by the impact force ΔV (k) and the speed change amount ΔE (k), a sufficient impact force is not generated in the early stage of the collision to be triggered. Therefore, it was also difficult to identify. Furthermore, examples of high-speed overlapping collisions with overlaps such as offset barrier collisions and offset car-to-car collisions (c)
In the case of, there is also a case where a collision cannot be determined because only a weak acceleration signal is generated by the time when the deployment trigger should be performed despite the high-speed collision and the acceleration gradient amount ΔGr (k) does not exceed the threshold Grd. It was undeniable.

According to the present invention, the threshold value of the acceleration gradient amount in addition to the impact force and the speed change amount is determined as a threshold, and a collision determination area based on the speed change amount and the acceleration gradient amount is devised. It is intended to be able to execute with high accuracy.

[0013]

In order to achieve the above-mentioned object and to solve the above-mentioned problems, the present invention provides an acceleration sensor for detecting an acceleration applied to a vehicle, and a remarkable function at the time of a collision of a vehicle extracted from the acceleration. Impact force calculating means for calculating an impact force by taking an absolute value of a specific band component appearing; and long section integrating means for calculating the long section speed change amount by integrating the acceleration over a relatively long section up to a current value. A short section integrating means for calculating the short section speed change amount by integrating the acceleration for a relatively short section up to the current value; and a differentiator for calculating the acceleration gradient amount by time differentiating the short section speed change amount. A subtractor for subtracting the speed change amount from the acceleration gradient amount to calculate a collision predicted value; and a subtractor for determining whether the impact force exceeds a predetermined threshold value or the long section speed change amount is a predetermined value. Exceed threshold Or the acceleration gradient amount is characterized in that the collision prediction value with exceeds a predetermined threshold value; and a judging means for making a collision determination upon whether exceeds a predetermined threshold.

Further, according to the present invention, the determination means includes an acceleration gradient amount comparator for determining a threshold value of the acceleration gradient amount, a collision prediction value comparator for determining a threshold value of the collision prediction value, An AND circuit that outputs an active signal when both the output of the comparator and the predicted collision value comparator are active, and a waveform shaper that shapes the output of the AND circuit into a waveform that lasts for at least a certain time Alternatively, the differentiator time-differentiates a short-term integral output given as discrete value data from the short-term integrator according to an arithmetic algorithm according to Simpson's differentiation formula.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. FIG. 1 is a circuit diagram showing an embodiment of a vehicle collision judging device according to the present invention, and FIG. 2 is a diagram showing a prediction judging region by the prediction judging circuit shown in FIG.

The vehicle collision judging device 21 shown in FIG. 1 is different from the conventional device 1 in that a prediction judging circuit 22 is newly provided in place of the differentiator 14 and the comparator 15. This prediction judgment circuit 2
2 is a short section integrator 2 for smoothing the acceleration data Ga (k) fetched from the low-pass filter circuit 3a via the AD converter 19a by short section integration and calculating a short section speed change amount.
3, a differentiator 24 for differentiating the short-range speed change amount with time to calculate an acceleration gradient amount, and a subtractor 25 for subtracting the speed change amount from the acceleration gradient amount to calculate a collision prediction value. And an acceleration gradient amount comparator 26 for determining the acceleration gradient amount as a threshold value based on the threshold value Grd, and a collision prediction value comparator 27 for determining a collision prediction value as a threshold value based on the threshold value GV. And an AND gate circuit 28 for outputting an active signal when both the outputs of the gradient amount comparator 26 and the predicted collision value comparator 27 are active; and an AND gate circuit 28
And a waveform shaper 29 for shaping the output of at least a predetermined time, for example, a period of 30 ms. 29a is a one-shot circuit, and 29b is an OR gate circuit.

The time differentiation by the differentiator 24 is performed by time-differentiating the short-term integral output according to an arithmetic algorithm according to Simpson's differentiation formula. According to Simpson's formula, the current value of the short-term integral output ΔVa (k)
And the data ΔVa (k−1), Δ
Using Va (k−2) and ΔVa (k−3), ｛ΔVa (k) + 3ΔVa (k−1) −3ΔVa (k−2) −
The time differential value is derived by the calculation of ΔVa (k−3)｝ / 6.

The judging circuit 13 comprises a pair of AND gate circuits 13a and 13b and an OR gate circuit 13c as in the prior art. The AND gate circuit 13b calculates the logical product of the output of the comparator 10 and the output of the prediction judging circuit 22. It differs from the conventional one in taking points. However, the comparator 10 and the AND gate circuit 13b
And the waveform shaper 12 between them is abolished. The digital signal processing unit 21a shown in the present embodiment performs an absolute value determination, a short section integration determination, a short section integration value differentiation determination (acceleration gradient amount determination), and a difference determination between the short section integration value and the short section integration differentiation value. The collision determination is made by integrating five types of determinations (collision predicted value determination) and long section integration determination, and the acceleration gradient amount determination and the collision predicted value determination are functions that are not available in the past.

The prediction judgment by the prediction judgment circuit 22 is performed inside and outside a prediction judgment area divided into a two-dimensional plane of the section integral value ΔVa (k) and the acceleration gradient amount ΔGa (k) in FIG. That is, the prediction determination region is defined by ΔGr (k)> Grd and ΔGr (k) −ΔVa (k)> GV, and when the condition included in the prediction determination region is satisfied, the AND gate circuit 26 An active signal is output. In this prediction determination area, the intersection point P (ΔVa (k) = Ti) of two boundary lines ΔGr (k) = Grd ΔGr (k) −ΔVa (k) = GV is determined in the course of a low-speed frontal collision. It is located between the curve (b) and the curve (b) for a low-speed head-on collision that does not determine a collision, and furthermore, the curve (c) for a high-speed overlap collision and the curve (d) for a high-speed head-on collision. Is characterized in that it includes a rising portion in the early stage of collision.

This makes it possible to identify conditions under which the conventional collision determination device 1 could not determine a collision, for example, identification of a low-speed frontal collision with no large difference in collision speed, and acceleration gradient amount Δ
High-speed overlapping collision with an offset such that Gr (k) decreases from a certain point of time, or a solid barrier in which both the acceleration gradient amount ΔGr (k) and the short-range speed change amount ΔVa (k) increase rapidly. A high-speed frontal collision with the vehicle can be identified with high speed and high accuracy. Further, the output active signal of the prediction determination circuit 22 is supplied to the AND gate circuit 13b together with the threshold determination output exceeding the threshold value Vrs2 of the comparator 10 connected to the short-range integrator 7 described above. Even when the collision determination condition satisfies the prediction determination area when traveling on a rough road, the deployment trigger is erroneously applied to the short-range integrator 24a because the short-range integrator 24a does not generate a speed change amount as large as the threshold value can be determined by the comparator. Never.

Regarding the acceleration gradient amount and the collision predicted value exceeding the threshold values of the comparators 26 and 27, even if the logical product output of the two is instantaneous, at least a fixed time is maintained. Since the waveform is shaped and processed, the presence of the acceleration gradient amount that has reached the dangerous level and the presence of the collision predicted value are continuously specified for a certain period of time, and the collision determination can be provided as a signal waveform particularly suitable for logical judgment. This makes it possible to distinguish between low-speed head-on collisions in which there is almost no difference in collision speed or a high-speed and high-precision collision determination for a high-speed overlap collision in which the acceleration gradient amount does not significantly occur within the initial time for collision determination. can do.

Furthermore, since the differentiator 24 differentiates the short-term integral output given as discrete value data from the short-term integrator 23 according to an arithmetic algorithm in accordance with Simpson's differentiation formula, the differentiator 24 gives short-term integral data as discrete value data. The interval integral output can be time-differentiated by software processing, and can be calculated by addition / subtraction processing using the sample data three samples before the sample data indicating the current value, so that time differentiation by digital signal processing can be easily executed. it can.

In the above-described embodiment, the prediction determination area on the two-dimensional plane defined by the short interval integral value ΔVa (k) and the acceleration gradient amount ΔGr (k) is optional according to the type of the applicable vehicle. It can be set variably, for example, in the prediction determination area of FIG.
By adding a condition for Ti, it is possible to make a collision prediction determination only in an inverted triangular area excluding a rectangular area.
In addition, not only in the two-dimensional space defining the acceleration gradient amount ΔGr (k) and the interval integral value ΔV2 (k), but also a collision determination area based on the speed change amount ΔV (k) and the impact force ΔE (k) is defined. In a two-dimensional space, a collision determination can be made more comprehensively by adding a similar area restriction.

In the above embodiment, the short-range integrator 23 is used as a means for smoothing the acceleration data before the differentiator for calculating the acceleration gradient amount ΔGr (k). As shown in the vehicle collision determination device 31 shown, for example, a smoothing circuit 32 such as a moving average processing circuit or a digital low-pass filtering circuit can be used instead. In this case, a dedicated short section integrator 33 is connected to the input side of the subtractor 25. A dedicated short section integrator 34 is also connected to the input side of the comparator 10. The acceleration data is supplied to the digital signal processing unit 21a from the AD converter 19a connected to the low-pass filtering circuit 3a for removing aliasing distortion without limiting the high-frequency band, and only to the absolute value circuit 4. The acceleration data is supplied through a band-pass filter 35 having a digital circuit configuration.

[0025]

As described above, the present invention detects an acceleration applied to a vehicle and calculates an impact force by taking an absolute value of a specific band component which is remarkably generated at the time of a collision of the vehicle and which is extracted from the acceleration. In addition, the acceleration is integrated over a relatively long interval to a current value to calculate a long-section speed change amount, and the acceleration is integrated over a relatively short interval up to a current value to obtain a short-term speed change. Calculating the section speed change amount, calculating the acceleration gradient amount by time differentiating the short section speed change amount, and calculating the collision prediction value by subtracting the speed change amount from the acceleration gradient amount, When the impact force exceeds a predetermined threshold value, or the long-range speed change amount exceeds a predetermined threshold value, or the acceleration gradient amount exceeds a predetermined threshold value, and the collision prediction value becomes a predetermined value. Exceeds the threshold of The collision prediction is obtained as the difference between the acceleration gradient amount and the speed change amount in the two-dimensional plane of the speed change amount of the short-term integral value and the acceleration gradient amount of the time derivative value. By judging the value based on a predetermined threshold,
The collision judgment area can be effectively narrowed. For example, a low-speed head-on collision requiring a collision judgment of about 15 mph and a low-speed head-on collision requiring no collision judgment of about 12.5 mph are calculated. It is possible to clearly distinguish between inside and outside of the collision determination area exceeding the threshold value, thereby enabling discrimination between low-speed head-on collisions where there is almost no difference in collision speed,
Furthermore, even in the case of a high-speed collision such as an overlap collision in which the acceleration gradient amount does not significantly occur within the initial time for which the collision determination is to be made, it is possible to make a high-speed prediction determination based on the threshold determination output of the short-term integral value. In addition, by extracting a specific band component that is remarkable at the time of collision, it is possible to judge between a very weak pole collision and traveling on a rough road by using a difference in impact force within a time when a speed change amount should be determined, There is an excellent effect that a collision event in which a non-collision object excessively absorbs collision energy can be determined using the speed change amount by the section integral value.

Further, according to the present invention, the judging means includes an acceleration gradient amount comparator for judging a threshold value of the acceleration gradient amount, a collision prediction value comparator for judging the collision prediction value as a threshold value, a gradient amount comparator and the collision amount comparator. An AND circuit that outputs an active signal when both outputs of the predicted value comparator are active, and a waveform shaper that shapes the output of the AND circuit into a waveform that lasts for at least a certain period of time, Regarding the acceleration gradient amount exceeding the threshold value of the comparator and the collision predicted value, the logical product output of both must be shaped into a waveform that lasts for at least a certain period of time, even if it is instantaneous. As a result, the acceleration gradient amount that has reached the danger level and the existence of the collision prediction value are continuously specified for a certain period of time, and the collision judgment is made as a signal waveform particularly suitable for logical judgment. Higher speed and higher accuracy for discrimination between low-speed head-on collisions where there is almost no difference in collision speed, or for high-speed overlapping collisions where the acceleration gradient amount does not significantly occur within the initial time for collision determination This has the effect that a collision can be determined.

Still further, according to the present invention, the differentiator is configured to time-differentiate the short-term integral output given as discrete value data from the short-term integrator according to an arithmetic algorithm in accordance with Simpson's differential formula. The short-term integral output given as value data can be time-differentiated by software processing, and can be calculated by addition and subtraction processing using sample data three samples before the sample data indicating the current value. There are effects such as easy execution.

[Brief description of the drawings]

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

FIG. 2 is a diagram showing a prediction determination area by a prediction determination circuit shown in FIG. 1;

FIG. 3 is a circuit configuration diagram showing another embodiment of the vehicle collision determination device of the present invention.

FIG. 4 is a circuit diagram showing an example of a conventional vehicle collision determination device.

FIG. 5 is a diagram illustrating a collision determination area by a determination circuit illustrated in FIG. 4;

[Explanation of symbols]

 21, 31 Vehicle collision determination device 21a Digital signal processing unit 22 Prediction determination circuit 23 Short interval integrator 24 Differentiator 25 Subtractor 26 Acceleration gradient amount comparator 27 Collision prediction value comparator

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) B60R 21/32

Claims (4)

(57) [Claims] An acceleration applied to a vehicle is detected, an impact value is calculated by taking an absolute value of a specific band component which is conspicuously appearing at the time of a collision of the vehicle extracted from the acceleration, and the acceleration is calculated up to a current value. A long section speed change is calculated by integrating over a relatively long section, and a short section speed change is calculated by integrating the acceleration over a relatively short section up to the current value. While calculating the acceleration gradient amount by time-differentiating the section speed change amount, the collision prediction value is calculated by subtracting the speed change amount from the acceleration gradient amount,
When the impact force exceeds a predetermined threshold value, the long-range speed change amount exceeds a predetermined threshold value, or the acceleration gradient amount exceeds a predetermined threshold value, and the collision predicted value is A collision determination method for a vehicle, comprising: determining a collision when a predetermined threshold value is exceeded. 2. An acceleration sensor for detecting an acceleration applied to a vehicle, and an impact force calculating means for calculating an impact force by calculating an absolute value of a specific band component which is remarkably generated at the time of a collision of the vehicle and is extracted from the acceleration. A long section integrating means for integrating the acceleration over a relatively long section to a current value to calculate a long section speed change amount; and integrating the acceleration for a relatively short section to the current value to obtain a short section speed change amount. A short section integrating means for calculating, a differentiator for calculating an acceleration gradient amount by time-differentiating the short section speed change amount, and calculating a collision prediction value by subtracting the speed change amount from the acceleration gradient amount. A subtractor, wherein the impact force exceeds a predetermined threshold, or the long-range speed change exceeds a predetermined threshold, or the acceleration gradient exceeds a predetermined threshold, and Collision forecast A collision judging device for judging a collision when the measured value exceeds a predetermined threshold value. 3. An acceleration gradient amount comparator for judging a threshold value of the acceleration gradient amount, a collision prediction value comparator for judging the collision prediction value as a threshold value, the gradient amount comparator and the collision amount An AND circuit that outputs an active signal when both outputs of the predicted value comparator are active, and a waveform shaper that shapes the output of the AND circuit into a waveform that lasts for at least a certain period of time. The vehicle collision judging device according to claim 2. 4. The method according to claim 2, wherein the differentiator time-differentiates the short-term integral output given as discrete value data from the short-term integrator according to a calculation algorithm based on Simpson's differentiation formula. Vehicle collision determination device.