JP3289612B2 - 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 in which the integrated value of a variable acceleration and the vibration energy of the acceleration are discriminated as threshold values in addition to the amount of speed change so that the collision determination of the vehicle can be executed at high speed and with high accuracy. The present invention relates to a determination method and a collision determination device.

[0002]

2. Description of the Related Art In recent years, safety in the event of a vehicle collision has been given particular importance, and a system for operating an occupant restraint such as an airbag that protects an occupant in the event of a collision has a determination time performance and a collision time suitable for proper deployment timing. With the goal of improving the discrimination performance or increasing the intelligence, it is constantly being improved.
When a collision is identified near the occupant's seat in the center of the cabin, a pure speed change amount lost by the vehicle can be measured by observing the generated acceleration. However, although the time required for the collision determination of the occupant restraint system is different from the proper deployment timing of the airbag and the like depending on the collision speed and the collision type, the early determination at the time when the acceleration has not yet sufficiently occurred in the early stage of the collision is performed. Identification of periods during which acceleration is required and should not be deployed, and acceleration occurring in the time range close to the judgment time width at the time of high-speed collision due to riding on a curb, resulting in a large amount of speed change And so on has been the focus of this field.

For example, Japanese Patent Application Laid-Open No.
No. -40183 “collision determination device” determines a collision based on the amount of speed change generated during a vehicle collision based on the magnitude of the speed change gradient in a certain time interval, and further differentiates the speed change gradient into an acceleration gradient amount (acceleration change amount). Slope)
The collision judgment is based on the magnitude of the impact force or the magnitude of the impact force that takes the absolute value by extracting the specific frequency band of the acceleration, or the vehicle cannot be grasped only by the simple speed change at the time of the collision. A method has been used in which the degree of change in the speed change amount caused by the complicated breakage and compression of the structure is captured to determine a collision, and whether the occupant restraint system can be operated from various angles is determined.

[0004]

In order to improve the performance of an occupant restraint system including an airbag or the like, a medium-speed collision in which the occupant can be safely restrained only by the seat belt when the occupant wears a seat belt, for example, A technology to reduce unnecessary airbag deployment, or to switch the explosive power of airbag deployment appropriately according to the severity of the collision and the occupant's riding posture, etc., without determining collision in a 14 mph or 12 mph frontal collision High intelligence systemization technology is attracting attention.

However, when the prior art is viewed in light of such technical trends, the conventional vehicle collision determination apparatus is characterized by the characteristics of a vehicle collision that requires the operation of an occupant restraint system such as an airbag by combining various physical quantities. Captures by exceeding the threshold at the same time during a certain time period,
Moreover, the threshold value for judging each operation amount is fixed to a constant value from the beginning for each operation amount.
Therefore, there has been no attempt at all in attempting to change threshold determination criteria for various physical quantities according to factors relating to the riding posture of the occupant, for example, wearing or not wearing a seat belt. In addition, the calculation associated with the collision determination by the above-described conventional device, for example, the calculation of the speed change gradient during a certain period and the magnitude determination thereof are performed using a predetermined fixed period as a basic scale. Because it is used, for the acceleration gradient amount obtained by smoothing and differentiation after a certain period of time, and for the acceleration whose absolute value is extracted by extracting a specific frequency band, the magnitude of the amplitude is determined by the threshold value. There was no other suitable method other than the collision determination. That is, if the speed change greatly fluctuates for a moment, the only way to determine the magnitude of the change is to determine the collision. For example, in the case of a medium-speed head-on collision with the seat belt fastened, the collision is not considered Even if it is desired to make a determination, there is a problem that it is not possible to secure a margin for increasing the threshold value serving as a determination criterion, and it is difficult to deal with various collision events in detail. Moreover, this is a problem that cannot be avoided not only for medium-speed head-on collisions but also for all types of collision events, since each calculation amount is determined by its own threshold value regardless of the collision speed and collision type. There were many barriers to performance improvement, such as difficulty in achieving detailed considerations such as switching the deployment mode of the airbag depending on the severity of the airbag and the type of collision.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional problems, and determines the threshold value of the integrated value of the fluctuation acceleration and the amount of vibration energy in addition to the short-range speed change gradient, thereby making it possible to determine the collision of the vehicle at high speed. A collision determination device and a collision determination system for a vehicle that execute with high accuracy, do not determine a medium-speed frontal collision when the occupant wears a seatbelt, and vary the collision determination conditions according to the severity of the collision and the type of collision. It is intended to provide a method.

[0007]

In order to achieve the above object, a vehicle collision judging device according to the present invention comprises an acceleration sensor for detecting acceleration applied to a vehicle, and integrating the acceleration to a current value for a relatively short period of time. A short section speed change gradient calculating means for calculating a short section speed change gradient, and calculating an average acceleration by averaging the acceleration to a current value for a fixed section, and calculating the average acceleration only when the acceleration is larger than the average acceleration. Acceleration integral value calculating means for calculating a fluctuation acceleration integral value by integrating the acceleration into a constant interval, and a vibration for calculating the vibration energy amount of the acceleration by integrating the absolute value of the time difference from the current value of the acceleration to the current value for a certain period. An energy amount calculating means for determining threshold values of the short section speed change gradient, the fluctuation acceleration integrated value, and the vibration energy amount, and determining a collision by integrating the determination results; It is characterized in that it comprises a collision judging means.

The collision judging means may make a collision judgment when any of the short-range speed change gradient, the integrated variation acceleration value and the vibration energy amount exceeds a corresponding threshold value, or The variable acceleration integrated value calculation means corrects the average acceleration calculated by averaging the acceleration to a current value for a certain section by adding or subtracting a slope coefficient preset according to vehicle characteristics, and correcting the corrected average acceleration. Only when the acceleration is larger than the acceleration, the acceleration is integrated for a certain period to calculate a fluctuation acceleration integrated value.

Further, a collision event start detecting means for detecting the start of a collision event when the short section speed change gradient exceeds a comparatively small threshold value, and a timer for starting a timing operation in response to the detection of the start of the collision event. Means for determining the type of collision at the beginning of a collision by determining whether or not the short section speed change gradient exceeds a predetermined threshold value when a relatively short fixed time has elapsed after the operation of the timing means. And a seatbelt wearing state detecting means for detecting whether or not the occupant wears the seatbelt, and integrating the outputs of the respective means to obtain the short section speed change gradient, the fluctuation acceleration integrated value, and the vibration energy amount. A variable threshold value decision block for adaptively varying a threshold value.

[0010]

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 configuration diagram showing an embodiment of a vehicle collision determination device according to the present invention, FIG. 2 is a diagram showing a change in a variable acceleration integrated value during a medium-speed head-on collision, and FIG. FIG. 4 is a waveform diagram showing a specific example of the variable threshold value shown in FIG. 1 at the time of a middle / low-speed head-on collision, etc. FIG. FIG. 6 is a waveform diagram showing a specific example of the variable threshold value shown in FIG. 1, and FIG. 6 is a diagram showing an example of collision type identification based on a variable acceleration integrated value.

A vehicle collision determining apparatus 1 shown in FIG. 1 converts an acceleration signal detected by an acceleration sensor 2 into an AD converter 4 through a low-pass filter 3 for anti-aliasing.
The acceleration signal converted into discrete-value acceleration data G (k) is taken into the digital signal processing unit 1a.
As the acceleration sensor 2, a semiconductor acceleration sensor in which a stress-strain gauge utilizing a change in piezoresistance is incorporated on a semiconductor substrate with a pressure-receiving surface directed in the traveling direction of the vehicle is used. However, other than this, for example, a capacitance type semiconductor acceleration sensor or an acceleration sensor using a piezoelectric element can be used. The low-pass filter 3 removes high-frequency components exceeding 500 Hz in the present embodiment in order to eliminate the influence of aliasing distortion. The acceleration data G (k) captured in the digital signal processing unit 1a is subjected to a collision event start time detection and a collision type discrimination at the beginning of a collision based on a relatively small speed change gradient obtained by short-range integration. A short section integration determination, a fluctuation acceleration integration determination, and a vibration energy determination are performed, and a collision determination is performed by integrating these determination results.

The speed change gradient SV (k) calculated by the short interval integrator 5 is a relatively short fixed period, for example, 10 ms.
Are obtained by successively adding the acceleration data G (k) to the comparators 6, 7, and 13 having different threshold values. Among these three comparators, the comparator 13 is for determining the threshold value of the speed change gradient SV (k) used for the collision determination, whereas the comparators 6 and 7 are for determining the threshold value as the collision determination reference. The output is not directly involved in the collision determination as it is.

The threshold value ESDth of the comparator 6 is set to a value comparable to an acceleration of about 3 G so that the collision event start time of the vehicle can be detected. The use of the speed change gradient in the section of 10 ms for the detection of the collision event start time stabilizes the detection of the collision event start time, and also considers that erroneous detection is not frequently caused when traveling on a rough road or the like. Because. The output of the comparator 6 is supplied to the following one-pulse generator 8a, and the .DELTA.T1 timer 9a and .DELTA.T2 timer 9b start timing operation in synchronization with the pulse generated by the one-pulse generator 8a.

In this embodiment, the output of the ΔT1 timer 9a is supplied to the one-pulse generator 8b at the time of measuring 4 ms, and the pulse generated by the one-pulse generator 8b is supplied to one input terminal of the AND gate 10. For this reason,
An active signal is supplied to the variable threshold determination block 11 only when the value of the speed change gradient SV (k) exceeds the initial speed change gradient threshold GRDth of the comparator 7. The reason why the value of the speed change gradient SV (k) exceeds the initial speed change gradient threshold value GRDth of the comparator 7 is that the speed change gradient is relatively steep at the beginning of a collision event such as a high-speed head-on collision or a high-speed center pole collision. In a collision mode where Since the speed change gradient at the beginning of a collision event depends on the characteristics of the bumper structure at the front of the vehicle, ΔT
Timed operation time of one timer 9a and initial speed gradient threshold G
It is desirable to adjust the value of RDth, and it is better to adopt an optimal value based on empirical values. Further, depending on the vehicle, the speed change gradient at the beginning of the collision event may be used for discriminating between a total collision to be determined for collision and a non-determined collision event such as a low-speed head-on collision, or the initial speed change gradient threshold GRDt may be used.
By providing a large number of h, it is possible to apply to collision speeds of three or more patterns and collision type classification.

On the other hand, a ΔT2 timer 9 that measures 30 ms
The output of b is supplied to the one-pulse generator 8c, and the pulse generated by the one-pulse generator 8c is supplied to the variable threshold determination block 11. Therefore, the variable threshold determination block 11 includes a trigger signal indicating the time of 30 ms sent from the ΔT2 timer 9b via the one-pulse generator 8c, and the AND gate 10 indicating the collision type determination result based on the speed change gradient. Output signals are supplied, and in addition to these signals, a signal from a seat belt switch 12 for detecting whether or not the occupant wears the seat belt is supplied. For this reason, in the present embodiment, the threshold SVth, IEAt, which will be described later, is determined by the variable threshold determination block 11 in accordance with the presence / absence of seat belt wearing and the type of collision determined at the beginning of the collision.
h and VEth are variably set to several stages.

The output SV (k) of the short-range integrator 5 is used as one of the collision judgment calculation values as the variable threshold value SV of the comparator 13.
If the threshold value exceeds the variable threshold value SVth, an active signal is supplied to the final decision AND gate 28. In the present embodiment, the speed change gradient obtained by integrating over a short section over 10 ms for the detection of the collision event start time and the initial speed change gradient is determined by the comparator 13 as a threshold value. In order to increase the margin of discrimination when discriminating from the speed change gradient that occurs instantaneously as in the case of traveling, a speed change gradient obtained by integrating a short section in a longer section, for example, about 20 ms to 40 ms, is used as a comparator. Alternatively, the threshold value may be determined at 13.

On the other hand, the acceleration data G (k) is supplied to the moving averager 16 in order to calculate the fluctuation acceleration integrated value obtained by accumulating the rapidly changing speed change gradient. Acceleration data G up to .8 ms ago
By taking the moving average of (k), the average acceleration data MG
(K) is calculated. In the moving average section, since the frequency band to be averaged changes depending on the section width, the moving average section is a factor for adjusting the degree of extraction of the fluctuation acceleration integrated value described later. That is, the average acceleration data MG (k) is Here, n is the current value, T is the sampling period, and N
1 · T = 12.8 ms. The average acceleration data MG (k) thus obtained is added with a sign to the inclination coefficient d provided by the inclination coefficient unit 18 by the adder / subtractor 17 and sent to a comparator 19 where the acceleration data G (k) and For successive approximation.

The comparator 19 is provided only when the acceleration data G (k) is larger than the value MG (k) + d obtained by adding the inclination coefficient d set in advance to the average acceleration data MG (k) according to the vehicle characteristics. A coefficient signal instructing the multiplication of the coefficient value 1 is output, and the multiplier 20 receiving the coefficient signal multiplies the acceleration data G (k) by the coefficient value 1. As a result, a value MG obtained by adding the inclination coefficient d to the average acceleration data MG (k)
Only when the acceleration data G (k) is larger than (k) + d, the acceleration data G (k) is supplied to the short section integrator 21 subsequent to the multiplier 20. In the present embodiment, the short interval integrator 21 integrates the conditional acceleration data G (k) in a section up to 40 ms before the current value, and calculates the accumulated value IFA (k). That is, G (k) = G (k); When G (k) ≧ MG (k) + d G (k) = 0; When G (k) <MG (k) + d, where n is the current value and T is Sampling cycle, N2 · T
= 40 ms. The fluctuation acceleration integrated value IFA (k) thus calculated is output from the following comparator 22 to the variable threshold value IFA.
Compared with FAth, if the threshold value exceeds the variable threshold value IFAth, the comparator 22 outputs an active signal to the final decision AND gate 28.

FIGS. 2 and 3 show how the integrated variation acceleration value changes during a medium-speed head-on collision and a high-speed head-on collision, respectively. As is clear from these figures,
When the above calculation is converted into a speed amount and expressed, the integrated variable acceleration value is obtained only when the gradient of the actual speed change amount is larger than the gradient obtained by adding the slope coefficient d to the averaged speed change gradient. It can be seen that they are substantially accumulated. In other words, in the process of the vehicle front structure being lost due to the collision and being compressed, the more intense the collision such as the high-speed head-on collision shown in FIG. A sharp speed change gradient also occurs in the observed speed change amount, and the structure gradually holds up for a moment and the speed change gradient becomes gentle, but the rapid speed change gradient is immediately repeated. Conversely, in a relatively slow collision such as a medium-to-low-speed head-on collision shown in FIG. 2, the speed change gradient is less frequent and less frequent, and is much higher than in a high-speed head-on collision, a high-speed oblique collision, and a high-speed center pole collision. Only a small fluctuation acceleration integrated value is generated. Therefore, by adding or subtracting the inclination coefficient d to or from the average acceleration data MG (k), the inclination of the average speed gradient is finely adjusted and the variation acceleration integrated value is extracted in the same manner as when the moving average section is variably adjusted. Can be adjusted, and an appropriate collision determination can be made even for a medium-to-low speed frontal collision event.

Further, the acceleration data G (k) is used to extract an amount proportional to the vibration energy of the acceleration.
In step 3, the difference value G (k) -G (k-1) between the current value G (k) and the previous value G (k-1) is calculated. The difference value obtained here is converted to an absolute value |
(K) −G (k−1) | and supplied to the short interval integrator 25. In the present embodiment, the short section integrator 25 sequentially adds the difference values 5.2 ms before the current difference value to calculate the vibration energy amount VE (k). That is, Here, n is the current value, T is the sampling period, and N
3.T = 5.2 ms.

It can be seen that the above-mentioned vibration energy amount VE (k) increases in proportion to the amplitude and frequency of the acceleration signal and is proportional to the vibration energy. Short interval integrator 2
The amplitude extracted during the 5.2 ms integration interval of 5.2 becomes a large value when vibrating violently with a frequency component of acceleration in a band of about 200 Hz or more, and the process of severely breaking and compressing the vehicle front structure such as a collision event. Then, it occurs greatly. On the other hand, for an event such as off-road running on a rough road, an acceleration that causes a relatively large speed change amount but does not involve higher-frequency vibration is considered. , Vibration energy VE
Since (k) hardly occurs, in the present embodiment, it is used for discriminating between a collision event and running on a rough road. That is, the output of the short interval integrator 25 is compared with the variable threshold value VEth by the following comparator 26, and the variable threshold value VEt
When h is exceeded, an active signal is supplied to the set terminal of the flip-flop 27 of the next stage. The flip-flop 27 is reset by a reset pulse each time the start of a collision event is detected, waits for an active signal from the comparator 26, latches the active signal and sets the active signal to the AND gate 28 in the final stage. Is output.

The fact that the active signal from the comparator 26 is latched by the flip-flop 27 is obtained as a result of extracting the amplitude in a very short section of 5.2 ms in the short section integrator 25. Calculation value V
E (k) becomes an instantaneous vibration waveform and becomes a threshold value VEth
In order to avoid the inconvenience of repeating wandering with
To achieve the same purpose, the flip-flop 27 can be replaced by, for example, a one-shot circuit that outputs a sustain pulse over a certain period.

The final stage AND gate 28 is provided with the short-range speed change gradient SV (k) and the variation acceleration integral amount IFA.
When an active signal is supplied for all of (k) and the vibration energy amount VE (k), it is determined that the operation of the occupant restraint system such as an airbag is necessary, and a collision determination signal is output. It should be noted that the short-range speed change gradient SV (k) and the variation acceleration integral amount IFA (k) which are used as judgment materials are determined.
And the vibration energy amount VE (k) are both variable threshold values S variably set by the variable threshold value determination block 11.
Although the magnitudes are determined based on Vth, IFAth, and VEth, these variable thresholds are switched by the variable threshold determination block 11 in accordance with the lapse of time from the collision event start detection time. In addition, collision events can be finely classified to make an optimum collision judgment for each collision event.

Incidentally, the variable threshold value determination block 11
Threshold SVth, IFAt variably set by
h and VEth vary in a medium / low-speed head-on collision or a high-speed oblique collision, and in a high-speed head-on collision or a high-speed center pole collision, etc., and vary depending on whether or not a seat belt is worn at that time. . First, at the time of a middle / low speed frontal collision, as shown in FIG. 4, when the seat belt is not worn, the threshold value IFAth is changed to a medium level high value (M
(ID-HI) is switched to the medium level low value (MID-LO), and returns to the medium level high value (MID-HI) when ΔT2 time has elapsed from the detection of the start of the collision event.
However, the threshold values SVth and VEth remain unchanged at the low level (LO). When the seat belt is worn, the threshold value IFAth
Is switched from a high level (HI) to a medium level low value (MID-LO) when ΔT1 time has elapsed from the detection of the collision event start, and is set to a medium level low value when ΔT2 time has elapsed from the collision event start detection. (MID-LO) returns to the high level (HI). In this case, the threshold value SVt
Both h and VEth remain at the high level (HI) and do not change.

On the other hand, at the time of a high-speed head-on collision or a high-speed center pole collision, as shown in FIG. 5, when the seat belt is not worn, the threshold value IFAth is changed to ΔT1 time after the detection of the start of the collision event. At the time point, the medium level high value (MID-HI) is switched to the low value (LO), and when the time ΔT2 elapses from the detection of the start of the collision event, the low level (LO) returns to the medium level high value (MID-HI). . However, the threshold values SVth and VEth remain unchanged at the low level (LO). When the seat belt is worn, the threshold value IFAth is
When ΔT1 time elapses from the detection of the collision event, switching from the high level (HI) to the low level (LO) is set, and when ΔT2 time elapses from the detection of the collision event, the low level (LO) to the high level (HI). ). Further, the threshold value SVth is switched from a high level (HI) to a low level (LO) when ΔT1 time has elapsed since the detection of the start of the collision event, and from a low level (LO) when ΔT2 time has elapsed. Return to high level (HI). In addition, the threshold value VEth is set to a high level (H
It is set to switch from I) to low level (LO), and returns from low level (LO) to high level (HI) when ΔT2 time has elapsed from the detection of the start of the collision event.

FIG. 6 shows an example of collision type identification based on the integrated value of the fluctuation acceleration. For example, in a high-speed frontal collision at about 35 mph, the short-range velocity change gradient, the vibration energy amount, and the fluctuation acceleration integrated value exceed the threshold value in about 5 ms after the detection of the start of the collision event. A collision determination can be made promptly. Also,
In the case of a high-speed center pole collision or a high-speed oblique collision, the collision is determined slightly when the integrated value of the fluctuation acceleration exceeds the threshold value, although it is slightly delayed from the time of the high-speed head-on collision. On the other hand, in the case of a medium-speed head-on collision at 14 mph without seat belts, the short-range speed change gradient and vibration energy amount break through the threshold in about 7 ms after the collision occurs, and about 30 ms thereafter elapse Then, the integrated value of the fluctuation acceleration exceeds the threshold value, so that the collision can be determined with a margin within 50 ms after the occurrence of the collision. However,
In the case of a medium-speed front collision at 14 mph while wearing a seat belt, the threshold value of the variable acceleration integrated value is switched to a higher value after a period of, for example, about 40 ms after the detection of the start of the collision event. In practice, however, the integrated value of the fluctuation acceleration does not exceed the threshold value. For this reason,
It is possible to avoid unnecessary deployment of the airbag, which can be regarded as excessive safety, in a medium-speed head-on collision in a state where the seat belt is worn. Furthermore, in the case of a low-speed head-on collision at about 9 mph with the seat belt not worn, the short-range speed change gradient exceeds the threshold after the collision occurs, but the integrated fluctuation acceleration value and the vibration energy amount are low. Since the threshold value is not exceeded, it is possible to make a collision non-judgment instead of a collision judgment

As described above, the vehicle collision judging device 1
Is that the short-range speed change gradient SV (k), the fluctuation acceleration integrated value IFA (k), and the vibration energy amount VE (k) are each determined by a threshold value, and a collision determination is made by integrating the determination results. Although there is a time difference from the appropriate deployment timing of the airbag etc. depending on the collision speed and the collision type, it is possible to make an early judgment at the time when the acceleration is not yet sufficient at the beginning of the collision, and sufficient acceleration in the collision that should not be deployed Can be distinguished from a period in which acceleration occurs and a large amount of change in speed occurs due to acceleration occurring in a time region close to the determination time width at the time of a high-speed collision due to riding on a curb.

Further, the threshold value of only the short section speed change gradient SV (k) cannot be determined only by determining the threshold value.
Medium-speed head-on collision, which requires a collision judgment of about a mile, and 9 per hour
A low-speed head-on collision that does not require a collision determination of about a mile can be clearly distinguished by utilizing the difference in the variable acceleration integral value IFA (k). It is possible to discriminate between frontal collisions, and to extract a specific band component remarkable at the time of collision through vibration energy VE (k). It is possible to judge whether the vehicle is running or not by using a difference in vibration energy.

Further, the speed change gradient is substantially accumulated only when the integrated value of the fluctuation acceleration exceeds the gradient corrected by adding or subtracting the slope coefficient to or from the averaged speed change gradient. Compared to intense collision events such as collisions, the velocity change gradient is less frequent and less frequent, and relatively slow collision events such as medium-speed or low-speed head-on collisions that generate only a much smaller fluctuation acceleration integrated value are matched to vehicle characteristics. By adding or subtracting a slope coefficient of an appropriate value to or from the average acceleration data to finely adjust the slope of the average acceleration, the same effect as adjusting the moving average section can be obtained. Accurate collision determination can be made by adjusting the degree of value extraction.

Furthermore, the collision event start time detection and the collision type discrimination at the beginning of the collision are performed based on the relatively small speed change gradient obtained by the short-range integration. It can be set to adapt more flexibly, especially while maintaining the high-speed judgment performance of severe high-speed head-on collision, faster judgment performance of high-speed center pole collision and high-speed oblique collision, medium-speed head-on collision, and low-speed head-on collision In addition, it is possible to increase the judgment margin so that erroneous judgments will not be made even on rough roads such as curb climbing or off-road, and depending on whether or not the occupant wears a seat belt, for example, For a 14-mile medium-speed head-on collision, a collision judgment is made when the seatbelt is not worn, but not when the seatbelt is worn. Since the judgment criteria can be switched, at the time of a medium-speed head-on collision with the seat belt fastened, it is possible to sufficiently secure a margin for increase and a margin for increase when the threshold value is increased so that the collision is not judged. For all collisions, it is possible to accurately and reliably perform a collision determination or a collision non-determination adapted to the collision speed and the collision type.

In this embodiment, the collision judging method has been described based on a specific hardware configuration. However, in the present invention, the function of the digital signal processing unit 1a in FIG. 1 is replaced by software processing by a microprocessor. It is also possible. As a collision determination condition, a collision determination is made when the short section speed change gradient SV (k), the fluctuation acceleration integral amount IFA (k), and the vibration energy amount VE (k) all exceed the corresponding threshold values. For example, the short-range speed change gradient SV (k) exceeds the threshold value, and the fluctuation acceleration integral amount IFA (k) and the vibration energy amount V
When at least one of E (k) exceeds a corresponding threshold value, the combination logic of the threshold value determination output can be changed to another logic, for example, such that a collision determination is made.

[0032]

As described above, according to the present invention,
Detecting acceleration applied to the vehicle, calculating a short-section speed change gradient by integrating the acceleration to a current value for a relatively short fixed section, and calculating an average acceleration by averaging the acceleration to a current value for a certain section, Only when the acceleration is greater than the average acceleration, the acceleration is integrated for a certain period to calculate a fluctuation acceleration integrated value, and the absolute value of the time difference with respect to the current value of the acceleration is integrated for a certain period up to the current value. Since the vibration energy amount of the acceleration is calculated, the short-range speed change gradient, the fluctuation acceleration integral value, and the vibration energy amount are each determined by a threshold value, and the collision determination is made based on the determination results. Although there is a time difference from the appropriate deployment timing of the airbag etc. depending on the collision speed and the collision type, it is possible to make an early judgment at the initial stage of the collision when acceleration is not yet sufficient. In the case where the acceleration is not sufficiently developed, the acceleration is generated in a time range close to the determination time width at the time of a high-speed collision due to the climbing of the curb, or a large speed change is caused. An excellent effect such as identification is achieved.

Further, according to the present invention, the collision judging means makes a collision judgment when all of the short-range speed change gradient, the integrated value of the fluctuation acceleration, and the vibration energy amount exceed corresponding thresholds. Therefore, a medium-speed head-on collision that requires a collision determination of about 14 miles per hour, for example, cannot be understood only by determining the threshold value of the short-section speed change gradient alone.
A low-speed head-on collision that does not require a collision judgment of about 9 mph can be clearly distinguished by using the difference in the variable acceleration integration value. In addition, since a specific band component that is remarkable at the time of a collision is extracted through vibration energy, almost a weak pole collision and traveling on a rough road can be performed during a time in which a speed change gradient is to be determined. This has the effect of making a determination using the difference.

Further, the variable acceleration detecting means calculates an average acceleration calculated by averaging the acceleration to a current value for a certain section,
Correction is performed by adding or subtracting a preset slope coefficient according to vehicle characteristics, and only when the acceleration is larger than the corrected average acceleration, the acceleration is integrated for a certain period to calculate a variation acceleration integrated value. Therefore, the speed change gradient is substantially accumulated only when the integrated value of the fluctuation acceleration exceeds the gradient corrected by adding or subtracting the slope coefficient to or from the averaged speed change gradient. In the process of being lost due to a collision and being compressed by the collision, a large amount of energy is lost instantaneously when the vehicle travels due to the collision. Severe collisions, such as high-speed head-on collisions, in which the speed change gradient becomes gentler as the object holds up, but a sharp speed change gradient is immediately generated and wrinkle-like changes are repeated. Compared to elephants, the speed change gradient is less frequent and less frequent, and relatively slow collision events, such as medium-speed or low-speed head-on collisions, in which only a much smaller variation acceleration integrated value is generated, can be adjusted to appropriate values according to vehicle characteristics. By adding or subtracting the slope coefficient to or from the average acceleration data and finely adjusting the slope of the average acceleration, the same effect as adjusting the moving average section can be obtained. It is possible to obtain an effect such that an accurate collision determination can be made by adjusting.

Further, a collision event start detecting means for detecting the start of a collision event when the short-range speed change gradient exceeds a relatively small threshold value, and starts a timing operation in response to the detection of the start of the collision event. A collision mode is determined at an early stage of the collision by determining whether the short section speed change gradient exceeds a predetermined threshold value at a point in time when a relatively short fixed time has elapsed after the operation of the timer means. Means, a seat belt wearing state detecting means for detecting whether or not the occupant wears the seat belt, and integrating the outputs of the respective means to obtain each of the short section speed change gradient, the fluctuation acceleration integrated value, and the vibration energy amount. A variable threshold value decision block for adaptively varying the threshold value is provided, so that the detection of the collision event start time and the initial stage of the collision can be performed based on the relatively small speed change gradient obtained by the short interval integration. It can be applied to collision type discrimination, and can be set to more flexibly adapt to the collision characteristics of the vehicle and the judgment timing requirements. Combines faster judgment performance for high-speed diagonal collisions and discrimination performance for medium-speed head-on collisions and low-speed front-end collisions, and also increases the margin for judgment so that erroneous judgments can be made even on rough roads such as curb climbing and off-road Depending on whether or not the occupant wears a seat belt, for example,
For medium-speed head-on collision of miles, a collision judgment is made when the seat belt is not worn, but the judgment criteria can be switched so that the collision judgment is not made when wearing the seat belt, so at the time of a medium-speed head-on collision with the seat belt fastened, It is possible to secure a sufficient margin and an increase margin when increasing the threshold value so as not to determine this as a collision without determining it as a collision. Excellent effects such as accurate and reliable determination can be obtained.

[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 change in a fluctuating acceleration integrated value at the time of a medium-speed head-on collision.

FIG. 3 is a diagram illustrating a change in a fluctuating acceleration integrated value during a high-speed head-on collision.

FIG. 4 is a waveform chart showing a specific example of the variable threshold shown in FIG. 1 at the time of a middle / low speed frontal collision.

5 is a waveform chart showing a specific example of the variable threshold value shown in FIG. 1 at the time of a high-speed head-on collision or the like.

FIG. 6 is a diagram showing an example of collision type identification based on a variation acceleration integrated value.

[Description of Signs] 1 Vehicle collision determination device 1a Digital signal processing unit 2 Acceleration sensor 3 Low pass filter 4 A / D converter 5,21,25 Short section integrator 6,7,13,19,22,26 Comparator 8a, 8b, 8c One-pulse generator 9a, 9b Timer 10, 28 AND gate 11 Variable threshold decision block 12 Seat belt switch 16 Moving averager 17 Adder / subtractor 18 Slope coefficient unit 20 Multiplier 23 Differentiator 24 Absolute value calculator 27 flip-flops

Continuation of the front page (56) References JP-A-8-40183 (JP, A) JP-A-7-186876 (JP, A) JP-A-7-144602 (JP, A) JP-A-7-323803 (JP) JP-A-7-277133 (JP, A) JP-A-7-165008 (JP, A) JP-A-7-277123 (JP, A) JP-A-6-211100 (JP, A) 8-11674 (JP, A) JP-A-9-104320 (JP, A) JP-A-3-148348 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B60R 21/32

Claims (6)

(57) [Claims] 1. An acceleration applied to a vehicle is detected, and the acceleration is integrated over a relatively short period of time to a current value to calculate a short section speed change gradient. Calculating an acceleration, calculating a fluctuating acceleration integrated value by integrating the acceleration for a certain period only when the acceleration is larger than the average acceleration, and calculating the absolute value of a time difference from the current value of the acceleration as a current value. Calculate the vibration energy amount of acceleration by integrating over a predetermined interval up to the threshold, determine the threshold value of the short-range speed change gradient, the integrated value of the fluctuation acceleration and the vibration energy amount, and make a collision determination by integrating the determination results. A method for determining a collision of a vehicle. 2. The method according to claim 1, wherein the integrated value of the fluctuation acceleration is corrected by adding or subtracting a slope coefficient preset according to vehicle characteristics to an average acceleration calculated by averaging the acceleration to a current value for a certain section. 2. The vehicle collision determination method according to claim 1, wherein the method is performed by calculating a fluctuating acceleration integrated value by integrating the acceleration for a certain period only when the acceleration is larger than the corrected average acceleration. . 3. An acceleration sensor for detecting an acceleration applied to a vehicle, a short section speed change gradient calculating means for calculating a short section speed change gradient by integrating the acceleration to a current value in a relatively short fixed section, and calculating the acceleration. A variation acceleration integrated value calculating means for calculating an average acceleration by averaging a constant section up to a current value, and calculating a variation acceleration integrated value by integrating the acceleration for a certain section only when the acceleration is greater than the average acceleration; Vibration energy amount calculating means for calculating the vibration energy amount of the acceleration by integrating the absolute value of the time difference from the current value of the acceleration with respect to the current value for a certain period to the current value; A collision judging device for a vehicle, comprising: a collision judging means for judging the amount of energy as a threshold value and integrating the judgment results to judge a collision. 4. The collision judging means makes a collision judgment when all of the short-range speed change gradient, the integrated variation acceleration value, and the vibration energy amount exceed corresponding threshold values. The vehicle collision determination device according to claim 3. 5. The variable acceleration integral value calculating means corrects the average acceleration by adding or subtracting a slope coefficient preset according to vehicle characteristics to an average acceleration calculated by averaging the acceleration to a current value for a certain section. 4. The vehicle collision judging device according to claim 3, wherein only when the acceleration is larger than the corrected average acceleration, the acceleration is integrated for a certain period to calculate a variation acceleration integrated value. 6. A collision event start detecting means for detecting the start of a collision event when the short section speed change gradient exceeds a comparatively small threshold value, and a timing for starting a timing operation in response to the detection of the start of the collision event. Means for determining the type of collision at the beginning of a collision by determining whether or not the short section speed change gradient exceeds a predetermined threshold value when a relatively short fixed time has elapsed after the operation of the timing means. And a seatbelt wearing state detecting means for detecting whether or not the occupant wears the seatbelt, and integrating the outputs of the respective means to obtain the short section speed change gradient, the fluctuation acceleration integrated value, and the vibration energy amount. The vehicle collision determination apparatus according to claim 3, further comprising a variable threshold value determination block that adaptively changes a threshold value.