JP2014234076A - Collision detection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a collision detection device performing a high-speed collision determination with high precision which is less susceptible to variations in floor deceleration due to a vehicle structure.SOLUTION: A floor deceleration continuation time calculation section 6 calculates continuation time that a deceleration speed detected by a floor sensor 1 exceeds a first threshold value. A threshold value determination section 7 has a threshold value pattern that determines a relationship between continuation time and a second threshold value, and determines the second threshold value according to the continuation time calculated by the floor deceleration continuation time calculation section 6. A threshold value comparison section 8 compares a detection value of a front sensor 2 with the second threshold value determined by the threshold value determination section 7 so as to determine whether to activate occupant protection devices 10a and 10b.

Description

  The present invention relates to a collision detection device that detects a collision of a vehicle and determines whether or not an occupant protection device needs to be activated.

  Conventionally, as a method of starting an occupant protection device such as an air bag, a sensor for detecting a vehicle state such as a deceleration sensor (acceleration sensor) is installed in the vehicle, and the sensor output exceeds a preset threshold value. There was a way to start when it was big.

  Furthermore, in recent years, early start-up necessity determinations are required for high-speed collisions that are fatal to passengers. Maps are generated from the output of multiple sensors arranged at two locations on the vehicle, and There is a method of extracting features and determining the necessity of activation (see, for example, Patent Document 1).

  In the method disclosed in Patent Document 1, first, a two-time integration of the output of a floor deceleration sensor installed at the center of the vehicle is calculated, and a threshold value is determined based on the two-time integration of the calculated floor deceleration. The means determines a front sensor threshold value from a preset threshold pattern. When the output of the front deceleration sensor installed at the front of the vehicle is equal to or greater than the front sensor threshold, it is determined that the occupant protection is a high-speed collision with a high degree of emergency, and when the output is less than the front sensor threshold, Judged as a medium / low-speed collision with a low level of protection urgency. At that time, the front sensor threshold value in the region where the twice integrated value of the floor deceleration is small is set lower than the front sensor threshold value in the large region, so that the early determination of the high-speed collision is performed.

JP 2003-220926 A

  However, a vehicle having a structure with a small amount of buffering from the front of the vehicle to the floor deceleration sensor (for example, the floor deceleration at the center of the vehicle where the installation distance between the floor deceleration sensor and the front deceleration sensor is short) For example, there is a member that transmits to the sensor), and the integral value of the floor deceleration twice increases rapidly at the time of a high-speed collision, and there is a possibility that the discriminability from the medium-speed / low-speed collision may be lowered.

  The present invention has been made to solve the above-described problems, and provides a collision detection device that performs high-speed, high-speed collision determination that is not easily affected by variations in floor deceleration caused by the structure of a vehicle. With the goal.

  The collision detection device according to the present invention is a first sensor that is disposed in the center of the vehicle and detects the deceleration of the vehicle, and a second sensor that is disposed in the outer portion of the vehicle and performs an output corresponding to an impact applied to the vehicle. A relationship between the duration time and the second threshold value, and a deceleration duration calculation unit for calculating a duration time during which the deceleration detected by the first sensor exceeds the first threshold value. A threshold value determination unit for determining a second threshold value according to the duration calculated by the deceleration duration calculation unit, and a detection value of the second sensor as a threshold value. A threshold value comparison unit that determines whether or not the occupant protection device needs to be activated is compared with the second threshold value determined by the determination unit.

  According to this invention, the duration when the deceleration detected by the first sensor exceeds the first threshold value is calculated, and the second threshold value and the second sensor detection corresponding to the duration time are calculated. Since it is determined whether or not the occupant protection device needs to be started by comparing the values, a collision detection device that makes high-precision high-speed collision determination that is not easily affected by variations in floor deceleration due to the vehicle structure is provided. can do.

It is a block diagram which shows the structure of the collision detection apparatus which concerns on Embodiment 1 of this invention. It is a figure which shows the structural example of the vehicle carrying the collision detection apparatus which concerns on Embodiment 1. FIG. 3 is a flowchart showing an operation of the collision detection apparatus according to the first embodiment. 6 is a graph showing temporal changes in floor deceleration and floor deceleration continuation time of the collision detection device according to the first embodiment. 6 is a graph showing a temporal change in floor deceleration continuation time of the collision detection apparatus according to Embodiment 1 and mapping between floor deceleration continuation time and front deceleration. 6 is a graph showing a change with time of front deceleration of the collision detection apparatus according to the first embodiment. It is a graph which shows the time-dependent change of floor deceleration 2 time integration calculated with the conventional collision detection apparatus, and mapping with floor deceleration 2 time integration and front deceleration. It is a graph which shows the modification of the threshold value pattern of FIG.5 (b). It is a block diagram which shows the modification of the collision detection apparatus which concerns on Embodiment 1. FIG.

Embodiment 1 FIG.
As shown in FIG. 1, the collision detection apparatus according to the first embodiment detects the collision of a vehicle and determines whether or not the occupant protection apparatuses 10a and 10b such as airbags need to be activated. (First sensor) 1, front sensor (second sensor) 2, and ECU (Electric Control Unit) 3.

  FIG. 2 shows a configuration example of a vehicle equipped with this collision detection device. In this example, the floor sensor 1 is installed on the vehicle floor (central part) to detect the vehicle deceleration Gfloor, and the front sensor 2 is installed on the vehicle front (front part) to detect the vehicle deceleration Gfront. To do. In addition, when installing ECU3 in a floor, you may arrange | position the floor sensor 1 inside the ECU3. In this example, a deceleration sensor (acceleration sensor) that detects vehicle deceleration is used as the floor sensor 1 and the front sensor 2. However, the front sensor 2 is not limited to the deceleration sensor, and any sensor that outputs in accordance with the impact applied to the vehicle, such as a pressure sensor that detects the deformation amount of the front, may be used. Further, a plurality of front sensors 2 such as front left and right may be arranged, and in that case, a deceleration sensor and a pressure sensor may be used in combination.

  The ECU 3 includes a communication interface (hereinafter referred to as I / F) 4 that acquires outputs of the floor sensor 1 and the front sensor 2, a microcomputer (hereinafter referred to as microcomputer) 5, and an occupant protection device drive circuit that drives the occupant protection devices 10a and 10b. 9 etc. are installed. The microcomputer 5 sequentially reads and executes the program recorded in the built-in memory, thereby performing a collision determination based on the outputs of the floor sensor 1 and the front sensor 2 to determine whether the occupant protection devices 10a and 10b are required to be activated. The functions of the floor deceleration duration calculation unit 6, threshold determination unit 7, and threshold comparison unit 8 are executed. When activation is required, an activation signal is sent to the occupant protection device drive circuit 9 to activate the occupant protection devices 10a and 10b.

Next, the operation of the collision detection apparatus will be described with reference to the flowchart shown in FIG. The microcomputer 5 repeats this flowchart every predetermined sampling period.
First, at a predetermined sampling period, the floor deceleration duration calculation unit 6 acquires the deceleration Gfloor detected by the floor sensor 1 via the communication I / F4, and the threshold comparison unit 8 determines the communication I / F4. The deceleration Gfront detected by the front sensor 2 is acquired (step ST1).

Subsequently, the floor deceleration duration calculation unit 6 compares the deceleration Gfloor with a predetermined threshold value ThrGfloor (first threshold value) (step ST2), and when the deceleration Gfloor exceeds the threshold value ThrGfloor. (Step ST2 “YES”), a predetermined addition value Ta is added to the floor deceleration continuation time Tgcont (step ST3).
The threshold value ThrGfloor is a value greater than, for example, noise, and is set to a level of deceleration that does not occur during normal traveling but occurs during a collision.

On the other hand, when the deceleration Gfloor is equal to or less than the threshold ThrGfloor (step ST2 “NO”) and the floor deceleration duration Tgcont is greater than 0 (step ST4 “YES”), the floor deceleration duration calculation unit 6 A predetermined subtraction value Tb is subtracted from the floor deceleration continuation time Tgcont (step ST5). When the floor deceleration continuation time Tgcont becomes negative as a result of subtracting the subtraction value Tb from the floor deceleration continuation time Tgcont (step ST6 “YES”), the floor deceleration continuation time calculator 6 calculates the floor deceleration continuation time Tgcont. Is set to 0 (step ST7).
In the case of step ST4 “NO” and step ST6 “NO”, the process proceeds to step ST8.

  Here, FIG. 4A shows a graph of the change over time of the deceleration Gfloor, and FIG. 4B shows a graph of the change over time of the floor deceleration duration time Tgcont. In the example of FIG. 4, Ta = Tb = 1 is set. When the deceleration Gfloor exceeds the threshold value ThrGfloor, 1 is added to the floor deceleration duration time Tgcont, and when it becomes less than the threshold value ThrGfloor, 1 is subtracted. .

  If this method is used, as shown in the graph of FIG. 5A, the floor deceleration is performed at a constant slope from the timing when the deceleration Gfloor exceeds the threshold ThrGfloor regardless of the collision speed V, 2V, 4V. The duration Tgcont tends to increase. In FIG. 5 (a), an object moves at a speed V on a vehicle with a small buffer (for example, the installation distance between the floor sensor 1 and the front sensor 2 is short, or there is a member that transmits front vibration to the floor sensor 1). The deceleration Gfront in the case of a collision (low speed collision) is indicated by a solid line, the deceleration Gfront in the case of a collision at a speed of 2V (medium speed collision) is indicated by a broken line, and the deceleration Gfront in the case of a collision at a speed of 4V (high speed collision) is indicated by a one-dot chain line. Although shown, since the increasing tendency is the same, the three lines overlap.

  In a vehicle having a structure with a small number of shock absorbers, the deceleration Gfloor of the floor sensor 1 suddenly increases at a high-speed collision compared to a low-speed collision, or the front vibration or the like is superimposed on the deceleration Gfloor. It varies. However, as shown in FIG. 5A, the floor deceleration continuation time Tgcont is not easily affected by variations in the deceleration Gfloor.

The addition value Ta and the subtraction value Tb may be the same value or different values.
When the subtraction value Tb is set larger than the addition value Ta, the time until the floor deceleration continuation time Tgcont converges to 0 is shortened, but the floor during the collision phenomenon (the deceleration Gfloor fluctuates). The fluctuation of the deceleration continuation time Tgcont increases. On the contrary, when the subtraction value Tb is set to a value smaller than the addition value Ta, the fluctuation of the floor deceleration continuation time Tgcont during the collision phenomenon becomes small, but the convergence of the floor deceleration continuation time Tgcont after the collision phenomenon is completed. Become slow. Based on this characteristic, Ta and Tb may be set.

  FIG. 6 is a graph of the change over time in the deceleration Gfront detected by the front sensor 2. The deceleration Gfront at the time of high-speed collision (speed 4V) is larger than the deceleration Gfront at the time of low-speed collision (speed V) and tends to occur early.

FIG. 5B is a graph mapping the relationship between the deceleration Gfront detected by the front sensor 2 and the floor deceleration duration Tgcont calculated by the floor deceleration duration calculation unit 6. As shown in FIG. 5A, the floor deceleration duration time Tgcont and the time are approximately proportional to each other. Therefore, the waveforms of the deceleration Gfront in FIGS. 5B and 6 have substantially the same shape.
Hereinafter, the flowchart of FIG. 3 will be described with reference to FIG.

  The threshold value determination unit 7 is set with a threshold ThrGfront (second threshold value) pattern for determining whether or not the occupant protection devices 10a and 10b need to be activated from the deceleration Gfront of the front sensor 2. Yes. This threshold value pattern defines the relationship between the floor deceleration duration time Tgcont and the threshold value ThrGfront. In the region where the floor deceleration duration time Tgcont is shorter than the predetermined time, the threshold value ThrGfront is greater than the longer region. Is set to a low value.

An example of the threshold pattern of the threshold ThrGfront is shown by a thick solid line in FIG. The occupant protection devices 10a and 10b are activated in the ON region where the deceleration Gfront of the front sensor 2 is greater than or equal to the threshold value ThrGfront, and not activated in the OFF region where the deceleration is less than the threshold value ThrGfront.
In this threshold pattern example, the deceleration Gfront generated in the region longer than the floor deceleration continuation time Tgcont = 20 is regarded as a collision that does not require activation of the occupant protection devices 10a and 10b, while the region is shorter than Tgcont = 20. The generated deceleration Gfront is regarded as a collision that requires activation of the occupant protection devices 10a and 10b. In a region longer than the floor deceleration duration Tgcont = 20, the threshold ThrGfront is set to a value lower than the peak value of the deceleration Gfront assumed at the time of a collision that does not require activation (for example, a collision at a speed V). ing. Further, the threshold value ThrGfront in the region shorter than the floor deceleration continuation time Tgcont = 20 is set lower than the value ThrGfront in the region longer than Tgcont = 20.

  Based on the threshold pattern, threshold determination unit 7 determines threshold ThrGfront corresponding to floor deceleration duration Tgcont calculated by floor deceleration duration calculation unit 6 (step ST8). Subsequently, the threshold value comparison unit 8 compares the threshold value ThrGfront with the deceleration Gfront (step ST9). When the deceleration Gfront is equal to or greater than the threshold value ThrGfront (step ST9 “YES”), the occupant protection device is driven. An activation signal is output to the occupant protection devices 10a and 10b via the circuit 9 (step ST10). On the other hand, when the deceleration Gfront is less than the threshold ThrGfront (step ST9 “NO”), a series of processes in the current sampling cycle is terminated.

Here, the collision determination method according to Patent Document 1 described above and the collision determination method according to the first embodiment will be compared.
FIG. 7A is a graph showing the change over time of the two-time integration of the deceleration Gfloor obtained by the collision determination method according to Patent Document 1. FIG. In a vehicle with a small number of buffer parts, the deceleration Gfloor varies depending on the collision speed, and therefore, the double integrated value of the deceleration Gfloor tends to increase rapidly during a high-speed collision (speed 4V). Therefore, when the relationship between the double integration of the deceleration Gfloor and the deceleration Gfront is mapped, as shown in FIG. 7B, the deceleration Gfront of the low-speed collision (speed V) and the deceleration Gfront of the high-speed collision (speed 4V) are obtained. May overlap, and the discriminability of high-speed collisions decreases. In the example of FIG. 7B, a high-speed collision (speed 4V) is determined at time T2, and the occupant protection devices 10a and 10b are activated.

  On the other hand, in the first embodiment, by determining the threshold ThrGfront of the deceleration Gfront based on the duration of the deceleration Gfloor, it is difficult to be affected by variations in the deceleration Gfloor at the time of high-speed collision determination. Further, instead of increasing while increasing the slope as in the case of the integral value twice, the floor deceleration continuation time Tgcont increases with a constant slope as shown in FIG. The deceleration continuation time Tgcont can converge to 0, and it is easy to cope with a collision phenomenon in a short period such as a secondary collision. Furthermore, as shown in FIG. 5B, a high-speed collision (speed 4V) can be determined early at time T1.

  As described above, according to the first embodiment, the collision detection device is arranged at the center of the vehicle to detect the deceleration of the vehicle, and according to the impact applied to the vehicle at the front of the vehicle. A front sensor 2 that performs output, a floor deceleration duration calculation unit 6 that calculates a floor deceleration duration Tgcont when the deceleration Gfloor detected by the floor sensor 1 exceeds a threshold ThrGfloor, and a floor deceleration duration Threshold determination for determining the threshold ThrGfront according to the floor deceleration duration Tgcont calculated by the floor deceleration duration calculation unit 6 having a threshold pattern that defines the relationship between Tgcont and the threshold ThrGfront. Part 7 and the detection value of front sensor 2 compared with threshold value ThrGfront determined by threshold value determination part 7 Membered protection device 10a, and the structure and a determining threshold value comparator 8 activation necessity of 10b. Thus, by using the floor deceleration continuation time Tgcont to determine the threshold value ThrGfront of the front sensor 2, a high-accuracy high-speed collision determination that is hardly affected by variations in the floor deceleration Gfloor caused by the structure of the vehicle is performed. be able to.

  Further, according to the first embodiment, the front sensor 2 is not limited to the deceleration sensor that detects the deceleration of the vehicle, and may be a pressure sensor that detects the deformation amount of the front. Since the pressure sensor can detect a wide range of deformation, the number of sensors installed can be reduced.

  Further, according to the first embodiment, the floor deceleration duration calculation unit 6 adds a predetermined amount to the floor deceleration duration Tgcont when the deceleration Gfloor detected by the floor sensor 1 exceeds the threshold ThrGfloor. The value Ta is added. Thereby, addition of noise and floor deceleration continuation time Tgcont during normal traveling can be prevented, and erroneous determination can be prevented.

  Further, according to the first embodiment, the floor deceleration continuation time calculation unit 6 determines that the floor deceleration continuation time Tgcont becomes 0 when the deceleration Gfloor detected by the floor sensor 1 is equal to or less than the threshold ThrGfloor. Is configured to subtract a predetermined subtraction value Tb from the floor deceleration continuation time Tgcont. Thereby, the floor deceleration continuation time Tgcont is converged to 0 in a short time with respect to the output of the deceleration Gfloor caused by the non-collision while preventing a rapid fluctuation of the floor deceleration continuation time Tgcont during the collision phenomenon. It is possible to prevent erroneous determination.

  Further, according to the first embodiment, the threshold value ThrGfront of the floor deceleration duration time Tgcont shorter than the predetermined time is set lower than the threshold value ThrGfront of the floor deceleration duration time Tgcont longer than the predetermined time. By using the threshold pattern, early determination is possible when the output of the front sensor 2 becomes large at the beginning of the collision due to a high-speed collision or the like.

  In the example of FIG. 5B, the threshold value pattern set in the threshold value determination unit 7 is a pattern that changes in a slope shape with the floor deceleration duration time Tgcont = 20 as a boundary. For example, as shown in FIG. 8, a pattern that changes stepwise may be used.

  Further, as shown in FIG. 8, the threshold value ThrGfront in the time zone T3 in which the floor deceleration continuation time Tgcont includes 0 may be set higher than the threshold value ThrGfront other than the time zone T3. In this case, it is possible to prevent an erroneous determination with respect to an impact only at the front (impact that does not require activation of the occupant protection devices 10a and 10b such as hammering and animal impact).

  Furthermore, as shown in the block diagram of FIG. 9, an LPF (Low Pass Filter) processing unit 11 is provided in the preceding stage of the floor deceleration duration calculation unit 6 to perform low-pass filter processing on the deceleration Gfloor and reduce the post-processing reduction. The speed Gfloor may be compared with the threshold value ThrGfloor. In the case of this configuration, the vibration component of the deceleration Gfloor during the collision phenomenon can be suppressed by the low-pass filter processing, so that the addition of the floor deceleration continuation time Tgcont during the collision phenomenon can be prevented from being interrupted. As a result, a more accurate floor deceleration continuation time Tgcont can be calculated, which leads to high-accuracy high-speed collision determination.

  Similarly, an LPF processing unit 12 may be provided in front of the threshold comparison unit 8 so that the deceleration Gfront is subjected to low-pass filter processing, and the processed deceleration Gfront is compared with the threshold ThrGfront. In the case of this configuration, since the noise of the deceleration Gfront detected by the front sensor 2 can be removed, high-precision high-speed collision determination becomes possible.

In the present invention, any constituent element of the embodiment can be modified or any constituent element of the embodiment can be omitted within the scope of the invention.
For example, in the above description, a front collision is determined using a front sensor and a floor sensor, but a collision between a vehicle outer part other than the front is detected using a sensor and a floor sensor arranged in a vehicle outer part other than the front. You may make the structure to determine (it determines the collision of a rear using the sensor and floor sensor which are arrange | positioned at rear, etc.).

  DESCRIPTION OF SYMBOLS 1 Floor sensor (1st sensor), 2 Front sensor (2nd sensor), 3 ECU, 4 Communication I / F, 5 Microcomputer, 6 Floor deceleration continuation time calculation part, 7 Threshold determination part, 8 Threshold comparison unit, 9 occupant protection device drive circuit, 10a, 10b occupant protection device, 11, 12 LPF processing unit.

Claims (7)

In a collision detection device that determines whether or not an occupant protection device mounted on a vehicle is required to be activated,
A first sensor disposed in a central portion of the vehicle for detecting deceleration of the vehicle;
A second sensor arranged at the outer portion of the vehicle and performing an output according to an impact applied to the vehicle;
A deceleration duration calculation unit that calculates a duration during which the deceleration detected by the first sensor exceeds a first threshold;
A threshold value pattern that defines a relationship between the duration and the second threshold, and the second threshold is determined according to the duration calculated by the deceleration duration calculation unit; A value determination unit;
A threshold value comparison unit that compares the detection value of the second sensor with the second threshold value determined by the threshold value determination unit and determines whether or not the occupant protection device needs to be activated. A collision detection device.   The collision detection apparatus according to claim 1, wherein the second sensor is a deceleration sensor that detects a deceleration of the vehicle or a pressure sensor that detects a deformation amount of the outer portion of the vehicle.   The deceleration duration calculation unit adds a predetermined value to the duration when a deceleration detected by the first sensor exceeds the first threshold value. The collision detection apparatus according to claim 1 or 2.   The low-pass filter process part which performs a low-pass filter process with respect to the deceleration detected by the said 1st sensor, and outputs to the said deceleration continuation time calculation part is provided, The Claim 1 to Claim 3 characterized by the above-mentioned. The collision detection apparatus of any one of Claims.   The deceleration duration calculation unit subtracts a predetermined value from the duration until the duration reaches 0 when the deceleration detected by the first sensor is equal to or less than the first threshold value. The collision detection device according to any one of claims 1 to 4, wherein   In the threshold value pattern of the threshold value determining unit, the second threshold value having a duration shorter than a predetermined time is set lower than the second threshold value having a duration longer than the predetermined time. The collision detection device according to claim 1, wherein the collision detection device is provided.   The threshold value pattern of the threshold value determining unit is such that the second threshold value of the duration of a predetermined time zone including 0 is compared with the second threshold value of the duration time other than the predetermined time zone. The collision detection device according to claim 1, wherein the collision detection device is set to be high.

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