JPH1062443A - Apparatus for judging sharp decelerated state of vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To judge the presence/absence of the sign of sharp deceleration on the basis of a threshold value by setting acceleration when detected acceleration is within a definite range while setting a definite value when the detected acceleration is out of the definite range and calculating physical quality showing the moving tendency of a vehicle from a plurality of set accelerations. SOLUTION: An acceleration sensor 22 is connected to a controller 26 through an A/D converter 24 and the controller 26 is connected to an air bag apparatus 14. The acceleration detected by the acceleration sensor 22 is read and it is judged whether the acceleration is the upper limit value or more of a predetermined range or the lower limit value or less thereof and, when the acceleration is affirmed, it is replaced with the upper or lower limit value of the predetermined range to be set and, when the acceleration is negated, it is set as it is. A moving integrated value is calculated, for example, from ten accelerations from the acceleration read in an RAM 32 this time to acceleration read before ten to be set to the value showing the moving direction of a vehicle. This moving integrated value is compared with a predetermined threshold value and, at a time of the threshold value or more, it is judged that there is a sign of sharp deceleration in the vehicle and preparatory judge treatment is finished to transfer to main judge treatment.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for judging a sudden deceleration state of a vehicle during traveling of the vehicle.

[0002]

2. Description of the Related Art Conventionally, an occupant protection device such as an airbag device for protecting a seated occupant in a sudden deceleration state of a vehicle is mounted on a driver's seat side and a passenger seat side of a vehicle such as a passenger car. . There are mechanical igniters and electric igniters in this occupant protection system.Each occupant protection system operates reliably in the event of a sudden deceleration of the vehicle, while in all other cases, It is required not to work. Hereinafter, an airbag device which is an electric ignition type occupant protection device will be described.

[0003] The electric ignition type airbag device protects the occupant by inflating the bag body toward the occupant when a sudden deceleration state of the vehicle is detected. The importance of the function of the judging device to detect is emphasized.

For example, as a preliminary determination process, it is determined whether or not the vehicle has a sign of a sudden deceleration state, and when it is determined that the vehicle has a sign of a sudden deceleration state, the sudden deceleration state of the vehicle is finally determined. There is a determination device that performs the main determination process.

[0005] In the preliminary determination process in this determination device,
Based on the acceleration detected by the acceleration sensor attached to the vehicle, a physical quantity obtained by performing a simple arithmetic processing such as a sum of the acceleration is constantly calculated. If this physical quantity exceeds a predetermined threshold value, it is determined that the vehicle has a sign of a sudden deceleration state, and the processing shifts to this determination processing. Further, in this determination processing, a plurality of physical quantities such as a square value and an average value of the acceleration are calculated based on the acceleration detected by the acceleration sensor, and when this physical quantity exceeds a predetermined threshold, the physical quantity is suddenly calculated. It is determined that the vehicle is in a deceleration state. That is, in the present determination process, a complicated calculation process is required to calculate the physical quantity. If the calculation process is always performed, the load increases. It is determined in advance whether or not there is.

Accordingly, a preliminary determination process for performing a simple arithmetic process is always performed, and the process shifts to the main determination process only when it is determined that the vehicle has a sign of a sudden deceleration state, so that the load can be reduced. At the same time, the sudden deceleration state of the vehicle can be reliably detected. When the sudden deceleration state of the vehicle is detected, for example, the airbag device operates.

[0007]

However, in the preliminary determination process in the conventional determination device, a simple calculation process is performed and a physical quantity is calculated. Therefore, the calculation process is performed using the acceleration detected by the acceleration sensor as it is. When applied, the physical quantity calculated when electrical noise detected as a very large value occurs exceeds the threshold.
As a result, there is a problem that the process shifts from the preliminary determination process to the main determination process even though there is no sign of a sudden deceleration of the vehicle.

In order to solve this problem, if the threshold value to be compared with the calculated physical quantity is set to a large value in consideration of the noise component, the vehicle is surely prevented from being suddenly decelerated without being affected by the noise component. Although it can be determined that there is a sign and the process can proceed to the main determination process, the time until this determination is made becomes longer. Accordingly, the transition from the preliminary determination processing to the main determination processing is delayed, and accordingly, the detection of the sudden deceleration state of the vehicle in the main determination processing may be delayed.

The present invention provides a vehicle rapid deceleration state determination device capable of suppressing the influence of noise and detecting the vehicle rapid deceleration state by shifting to the main determination process at an early stage in consideration of the above facts. With the goal.

[0010]

According to one aspect of the present invention, there is provided an acceleration detecting means for detecting an acceleration of a vehicle, wherein the vehicle detects a sudden deceleration state based on the detected acceleration. Preliminary determination means for determining whether or not there is a sign; and when the preliminary determination means determines that the vehicle has a sign of a sudden deceleration state, a final determination of a sudden deceleration state of the vehicle based on the acceleration of the vehicle. A vehicle rapid deceleration state determination device comprising: an acceleration detection unit configured to set the acceleration as it is when the acceleration detected by the acceleration detection unit is a value within a predetermined range; Acceleration setting means for setting a predetermined value when the value is a value; calculating means for calculating a physical quantity representing a movement tendency of the vehicle using a plurality of accelerations set by the acceleration setting means; Physical quantity is characterized in the fact that the determination means determines that the vehicle there is an indication of rapid deceleration state, the preliminary determination means from being configured when exceeds a predetermined threshold.

According to the first aspect of the present invention, the acceleration during running of the vehicle is always detected by the acceleration detecting means.
The acceleration setting means sets the acceleration as it is when the acceleration detected by the acceleration detecting means is within a predetermined range, and sets a predetermined value when the acceleration is out of the predetermined range. Here, electrically generated noise may be detected, but the value is large and is a value outside the predetermined range. If the value is outside the predetermined range, the noise is set by setting the predetermined value. Is detected, the acceleration value from which the noise is removed is set. The acceleration detected by the acceleration detecting means is either a positive sign or a negative sign. Therefore, if the acceleration A is set to the upper limit value or the lower limit value, it is determined that the predetermined range includes from + A to -A.
Regardless of the sign of the detected acceleration, it is possible to set according to the magnitude of the acceleration. When a range including a sign is set as the predetermined range in this way, a predetermined value according to the sign of the acceleration may be set in advance as a predetermined value set when the value is outside the predetermined range.

Further, the calculating means calculates a physical quantity indicating the tendency of the vehicle to move using a plurality of accelerations set by the acceleration setting means. The physical quantity includes at least one of a cumulative value, an average value, and a square value. The determining means determines that the vehicle has a sign of a sudden deceleration state when the physical quantity calculated by the calculating means exceeds a predetermined threshold value.

When the determining means determines that the vehicle has a sign of a sudden deceleration state, the determining means determines the sudden deceleration state of the vehicle. When the rapid deceleration state of the vehicle is detected by the main determination means, for example, the airbag device operates.

Accordingly, in determining the rapid deceleration state of the vehicle, the preliminary determination means removes noise by setting a predetermined value when the detected acceleration is out of the predetermined range, and removes the noise. A physical quantity representing a movement tendency is calculated using a plurality of values, and when the threshold value is exceeded, it is determined that the vehicle has a sign of a sudden deceleration state. Only when the preliminary determination means determines that the vehicle has a sign of a sudden deceleration state, the process proceeds to this determination means. As a result, the preliminary determination unit suppresses the influence of noise that is electrically generated, and shifts to the main determination unit at an early stage without shifting to the main determination unit due to the detection of noise. Can be detected.

[0015]

FIG. 1 shows a vehicle 12 to which a vehicle rapid deceleration state judging device 10 according to an embodiment of the present invention is applied.
It is shown. The arrow FR in the figure indicates the forward direction of the vehicle, and the arrow UP indicates the upward direction of the vehicle.

As shown in FIG. 1, an airbag device 14, the operation of which is controlled as required, is provided in the interior of the steering wheel 16 on the driver's seat 20 side in the cabin of the vehicle 12 and in front of the passenger seat 18 in front of the vehicle. It is installed. An airbag device is also mounted on the side of the rear seat and on each side of the seat for the purpose of improving occupant safety when the vehicle 12 is suddenly decelerated (not shown).

FIG. 2 shows a schematic configuration of a part of the vehicle sudden deceleration state judging device 10 for controlling the operation of the airbag device 14.

The vehicle sudden deceleration state judging device 10 includes an acceleration sensor 22 for detecting the acceleration of the vehicle 12, and the acceleration sensor 22 is connected to a controller 26 via an A / D converter 24. Further, the controller 26 is connected to the electric ignition type airbag device 14.

As the acceleration sensor 22, a sensor using a semiconductor or a piezoelectric element, a sensor using capacitance, or the like can be used, and outputs the acceleration G of the vehicle 12 as an analog value such as a voltage value.

The controller 26 to which the output terminal of the A / D converter 24 is connected includes a CPU 28, a ROM 30,
An M32, an input port 34 and an output port 36 are provided, which are connected to a system bus 38 so that data and commands can be exchanged with each other.

The electric ignition type airbag device 14
Are operated by the drive signal output from the output port 36, and are connected to the output port 36 of the controller 26.

In this embodiment, an example of an airbag device provided inside the steering wheel 16 will be described. The airbag device 14 includes an ignition device 40, a transfer agent 42, a gas generating agent 44, and a bag 46. Ignition device 40 installed in steering wheel 16
Is activated by a drive signal from the controller 26.
Thereby, the transfer agent 42 is ignited, and the gas generating agent 44 is burned by the ignition of the transfer agent 42. This gives N
₂ Large amounts of gas such as (nitrogen) are generated. This gas is injected into the bag body 46 of the airbag device 14 through a cooling filter (not shown), whereby the bag body 46 expands, breaks the cover of the steering wheel 16 and deploys into the vehicle interior. Therefore, in the airbag device 14, the bag body 46 expands toward the occupant when the vehicle 12 is rapidly decelerating, so that the occupant can be protected and safety can be improved.

Next, the operation of the embodiment of the present invention will be described with reference to the flowcharts of FIGS.

The processes shown in the flowchart are performed when the driver starts the engine when driving the vehicle 12 until the engine is turned off, or until the airbag device 14 is activated when a sudden deceleration state of the vehicle 12 is detected. It is executed repeatedly.

When the driver starts the engine, a preliminary determination process in step 102 of the main control routine shown in FIG. 3 is executed. In the preliminary determination process, a movement integrated value ΔV that indicates a movement tendency of the vehicle 12, that is, a physical quantity corresponding to a sign of a sudden deceleration state of the vehicle 12 is calculated, and the movement integrated value ΔV is set to a predetermined threshold value TH. If the vehicle speed exceeds the threshold, it is determined that the vehicle 12 has a sign of a sudden deceleration state.
Move to 4. Details regarding the preliminary determination processing will be described later.

In step 104, the present determination processing for determining the rapid deceleration state of the vehicle 12 is executed. In this determination processing, a plurality of physical quantities are calculated based on the acceleration of the vehicle 12 detected by the acceleration sensor 22. At this time,
In order to calculate a physical quantity (for example, an average value, etc.) that requires complicated arithmetic processing, a high-load arithmetic operation is performed, but the calculated physical quantity is compared with a predetermined threshold value. Thus, the sudden deceleration state of the vehicle 12 can be reliably determined. That is, when the calculated physical quantity exceeds the threshold value, it is determined that the vehicle 12 is in a rapid deceleration state. When a sudden deceleration state of the vehicle 12 is detected, a drive signal of the airbag device 14 is output, and the airbag device 1
4 is activated.

This determination processing is further performed after it is determined in the preliminary determination processing that the vehicle 12 has a sign of a sudden deceleration state. Therefore, the acceleration detected by the acceleration sensor 22 can be measured in a wide range without a predetermined range. Can be used.

Next, the details of step 102 in FIG. 3, that is, the preliminary determination processing for determining whether or not the vehicle 12 has a sign of a sudden deceleration state will be described with reference to the flowchart in FIG.

First, in step 106, an initial value is set. In the next step 108, the acceleration G detected by the acceleration sensor 22 mounted in the vehicle compartment is read.

In step 110, it is determined whether or not the acceleration G read in step 108 exceeds the upper limit of a predetermined range (G> 10). If an affirmative determination is made here, the acceleration G is replaced with "10", which is the upper limit of the predetermined range, in step 112, and a new value of the acceleration G is set. On the other hand, if a negative determination is made in step 110, the process directly proceeds to step 114 without replacing the upper limit.

In the next step 114, step 108
It is determined whether or not the acceleration G read in is smaller than the lower limit of the predetermined range (G <−10). If an affirmative determination is made here, the acceleration G
Is replaced with “−10”, which is the lower limit of the predetermined range, and a new value of the acceleration G is set. On the other hand, if a negative determination is made in step 114, the process directly proceeds to step 118 without replacing the lower limit.

As described above, in steps 110 and 114, it is determined whether or not the acceleration G is within a predetermined range.
In step 12 or step 116, a predetermined value is set according to the sign of the acceleration G. This predetermined range is a value obtained by a preliminary experiment as a range in which the influence of noise can be suppressed, and in the present embodiment, “+10
To -10 ".

For example, if the acceleration G read in step 108 is "50", an affirmative determination is made in step 110, and the acceleration G is set to "10" in step 112. If the acceleration G read in step 108 is, for example, "-50", an affirmative determination is made in step 114, and the acceleration G is set to "-10" in step 116.

In this manner, the predetermined range of the acceleration G is determined, and the acceleration G, which is a value outside the predetermined range, is replaced with a predetermined value and the acceleration G is newly set. It is no longer affected by noise (see FIGS. 5A and 5B). Therefore, it is possible to suppress the influence of noise that is instantaneously output as a very large value.

In the next step 118, the acceleration stored in the area _Gn in the predetermined area of the RAM is read, and the latest acceleration G fetched in the step 108 is stored in the area _Gn . Since the acceleration read in step 118 is the oldest acceleration stored in the predetermined area of the RAM shown in FIG. 6, it is described as acceleration G _{OLD in the} following description. If the acceleration G detected by the acceleration sensor 22 is outside the predetermined range, the acceleration G newly set to the predetermined value is stored in the area _Gn . Subsequently, in step 120, the acceleration G that is read this time and stored in the area _Gn and the oldest acceleration G among the accelerations that are read ten times before the currently read acceleration and stored in a predetermined area of the RAM. Based on _OLD , the moving integrated value ΔV is calculated from the following equations (1) and (2).
Is calculated.

ΔV _buf = ΔV + G _n (1) ΔV = ΔV _buf -G _OLD (2) The moving integrated value ΔV is stored in a predetermined area of the RAM.
It is determined based on the individual acceleration. In this way, the integrated movement value ΔV indicating the tendency of the vehicle 12 to move can be obtained. The integrated movement value ΔV is updated each time the acceleration sensor 22 detects the acceleration of the vehicle 12.

In the next step 122, step 120
Is compared with a predetermined threshold value TH. The threshold value TH is predetermined as a determination reference value by which it is possible to determine that the vehicle 12 has a sign of a rapid deceleration state based on the integrated movement value ΔV calculated in consideration of the influence of the noise component.

As a result of the comparison in step 122, when the moving integrated value ΔV does not exceed the threshold value TH (ΔV ≦ T
In H), the process proceeds to step 124, where the count value n is incremented. In the next step 126, the count value n
It is determined whether or not has reached a predetermined number “10” (n ≧ 10). This predetermined number is the number of accelerations G that can be stored in the predetermined area of the RAM, and is set to “10” in the present embodiment. That is, in the present embodiment, the integrated movement value ΔV is calculated based on the ten accelerations.

If an affirmative determination is made in step 126 (n ≧ 10), the count value n is reset in the next step 128, the process returns to step 108, and the above-described processing is repeatedly executed. On the other hand, if a negative determination is made in step 126 (n <10), step 108 is performed without resetting the count value n.
And the same processing is repeatedly executed. That is,
This means that the processes shown in steps 108 to 128 are constantly and repeatedly executed.

Steps 124 to 128 are performed in the RAM
A count value n representing the position of the oldest acceleration when the ten accelerations stored in the predetermined area are arranged in chronological order. Which, when stored in chronological order in the region G ₀ ~G ₉ of 10 of the acceleration within a predetermined area of the RAM as shown in FIG. 6, processing for specifying the acceleration of the oldest area of which It is carried out.

On the other hand, if it is determined in step 122 that the integrated movement value ΔV exceeds the threshold value TH (ΔV> TH), it is determined that the vehicle 12 has a sign of a sudden deceleration state, and a preliminary determination is made. The processing ends, and the main determination processing is executed.

In this determination processing, when it is determined that the vehicle 12 is in a rapid deceleration state by obtaining a plurality of physical quantities,
A drive signal for the airbag device 14 is output. When this signal is output, the airbag device 14 operates. In this case, a drive signal is output through the output port 36, and the drive signal is input to the airbag device 14 and the ignition device 40
Activate As a result, the gas generating agent 44 burns in the airbag device 14 to generate a large amount of N ₂ gas and the like.
As a result, the bag 46 of the airbag device 14 is inflated.

FIGS. 5A and 5C show graphs of the acceleration G detected by the acceleration sensor 22, and FIGS. 5B and 5D show the acceleration G detected.
, A movement integrated value Δ calculated in a preliminary determination process of determining whether or not there is a sign of a sudden deceleration state of the vehicle 12.
A graph showing the change in V is shown.

For example, as shown in FIG. 5A, when the acceleration (electric noise) is instantaneously output as a very large value by the acceleration sensor 22, the moving integrated value ΔV obtained is Since the calculation is performed for the ten noise values, the noise value is held for a predetermined period, and FIG.
As shown by the solid line. When a noise having a very large value is output as described above, the moving integrated value ΔV exceeds the threshold value TH due to the influence of the noise component, so that it is determined that the vehicle 12 has a sign of a rapid deceleration state. There is a possibility that the processing will shift to this determination processing. Therefore, the acceleration sensor 2
If the acceleration detected by step 2 is out of the predetermined range, the acceleration is set to a predetermined value. That is,
The shaded portion in FIG. 5A is removed. As a result, as shown by the imaginary line in FIG. 5B, the moving integrated value ΔV does not exceed the threshold value TH. Therefore, it is possible to prevent the transition to the main determination process due to the influence of the noise component.

FIG. 5C shows a graph of the acceleration G detected by the acceleration sensor 22 when the vehicle 12 is suddenly decelerated. The moving integrated value ΔV obtained in this case is shown in FIG.

Among the accelerations detected by the acceleration sensor 22, the acceleration outside the predetermined range (the shaded portion shown in FIG. 5C) is set to a predetermined value, and the vehicle 12 has a sign of a sudden deceleration state. It is determined by comparing with the threshold value TH. Since the threshold value TH at this time can be set to a value smaller than the threshold value TH ₁ (see FIG. 5B) conventionally determined in consideration of the noise component, a predetermined time (FIG.
It is possible to determine that the vehicle 12 has a sign of a sudden deceleration state earlier by ΔT shown in (D), and to shift to the present determination processing. That is, the transition from the preliminary determination processing to the main determination processing can be performed early.

As described above, according to the vehicle rapid deceleration state determining apparatus 10 according to the present embodiment, in the preliminary determination processing, when the acceleration G detected by the acceleration sensor 22 is a value outside the predetermined range, the predetermined value is determined. By setting the value, it is possible to suppress the influence of noise output as a very large value instantaneously. Further, since the threshold value TH to determine whether there are indications of state of rapid deceleration of the vehicle 12 can be set to a conventional value smaller than the threshold value TH _1, there are signs of rapid deceleration state of the vehicle 12 In this case, it is possible to detect this early and shift to the main determination process.

In this embodiment, when calculating the integrated movement value ΔV, the calculation is performed using ten accelerations G detected by the acceleration sensor 22, but the number of accelerations G used in the calculation is limited to ten. It is not something to be done.

Further, in the preliminary determination processing, the movement integrated value ΔV of the acceleration G is used as a physical quantity indicating the movement tendency of the vehicle 12.
Is calculated, but an average value, a square value, or the like of the acceleration G may be calculated.

[0050]

As described above, in the vehicle rapid deceleration state judging device according to the present invention, the preliminary judging means sets the predetermined value when the detected acceleration is out of the predetermined range. It is possible to calculate a physical quantity indicating the tendency to move using a plurality of set values, and determine that the vehicle has a sign of a sudden deceleration state when the threshold value is exceeded. There is an excellent effect that it is possible to shift to the main determination means early without moving to the main determination means due to noise.

[Brief description of the drawings]

FIG. 1 is a schematic perspective view showing a vehicle equipped with an airbag device.

FIG. 2 is a schematic configuration diagram illustrating a schematic configuration of a part of a vehicle rapid deceleration state determination device according to an embodiment of the present invention.

FIG. 3 is a flowchart illustrating a main control routine of the vehicle sudden deceleration state determination device according to the embodiment of the present invention.

FIG. 4 is a flowchart illustrating a preliminary determination process.

FIG. 5A is a graph showing acceleration including a noise component output by an acceleration sensor, and FIG. 5B is a graph showing a moving integrated value ΔV calculated based on FIG. (C)
Shows acceleration G detected by the acceleration sensor when the vehicle is rapidly decelerating, and (D) is a graph showing the integrated movement value ΔV calculated based on (C).

FIG. 6 is a schematic diagram showing a predetermined area of a RAM for storing acceleration detected by an acceleration sensor.

[Explanation of symbols]

 Reference Signs List 10 vehicle rapid deceleration state determination device 12 vehicle 14 airbag device 22 acceleration sensor

Claims (1)

[Claims] An acceleration detecting means for detecting an acceleration of the vehicle; a preliminary determining means for determining whether or not the vehicle has a sign of a sudden deceleration state based on the detected acceleration; A vehicle rapid deceleration state determination device, comprising: a main determination unit that determines a vehicle rapid deceleration state based on the acceleration of the vehicle when it is determined that the vehicle has a sign of a rapid deceleration state. When the acceleration detected by the acceleration detector is a value within a predetermined range, the acceleration is set as it is, and when the acceleration is a value outside the predetermined range, the acceleration setting unit sets a predetermined value. Calculating means for calculating a physical quantity representing a movement tendency of the vehicle by using a plurality of set accelerations, and when the physical quantity calculated by the calculating means exceeds a predetermined threshold value, A vehicle rapid deceleration state determination device, comprising: a determination unit that determines that there is a sign of a rapid deceleration state;