JPH07304413A - Air bag collision computing device - Google Patents

Abstract

PURPOSE:To compute an air bag collision at a high speed and prevent the abnormality of a RAM. CONSTITUTION:This air bag collision computing device for a vehicle is provided with a memory means 5 storing the integration value integrated with the multiple detected data and all detected data, an integrating means 7 subtracting the oldest detected data from the integration value and adding the latest detected data by the interruption process with a short data processing interval, and an adding means 8 adding all detected data during the period when no interruption process is made by the main routine process with a long data processing interval to calculate the additional value. A difference forming means 9 calculates the difference between the integration value and the additional value. An abnormality judging means 10 generates the warning of an abnormality when the integration value and the additional value do not coincide with each other continuously for a fixed period, it substitutes the integration value of the memory means 5 with the present additional value when the difference between the integration value and additional value coincides with the difference between the values calculated previously and this time, and it substitutes the integration value of the memory means 5 with the present additional value when the additional value does not exceed the ignition judgment value and exceeds the integration value ignition judgment value.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air bag for instantaneously inflating an airbag with gas between a passenger and a steering wheel at the time of a vehicle collision to absorb kinetic energy of the passenger and reduce a secondary obstacle of the passenger. More specifically, the present invention relates to a bag system in which an ignition signal is generated when a deceleration exceeds a certain threshold value and a cumulative cumulative value of the deceleration while the deceleration exceeds a certain value reaches a certain value. The present invention relates to an airbag collision calculation device that performs calculation.

[0002]

2. Description of the Related Art Conventionally, in an air bag system in such a field, an impact (deceleration) at the time of a collision is detected by an acceleration sensor mounted on a vehicle body, and an ECU (electronic control unit) is used.
In (t), determine whether the collision should deploy the airbag,
When necessary, an electric signal is sent to an inflator mounted in the steering wheel to burn the gas generating agent and inflate the airbag. The airbag restrains the head or chest of the occupant and prevents the head and chest from colliding with the steering wheel or the windshield. Although a series of these operations vary depending on the collision mode and collision speed, it takes 10 to 30 ms from the collision to the collision determination, and 30 to 40 m until the airbag is completely inflated after the electric signal is output.
It has to be done in a very short time. The airbag receives and protects an occupant, and at the same time shrinks while absorbing energy by venting gas, and the completion time of all operations is about 0.1 to 0.15 seconds. The airbag system must operate reliably at one time and not at the other time, regardless of whether or not the airbag system operates once in the life of the vehicle. It should not be activated for collisions and minor collisions that do not require bag deployment.
Therefore, high reliability of the airbag system is required.

In a collision determination process for determining whether or not a collision should cause the airbag to be deployed by the ECU, the deceleration for a predetermined time beyond which the deceleration exceeds a certain threshold is cumulatively integrated (speed). There is used a logic that obtains a deceleration accumulation integral that performs and outputs an ignition signal when the deceleration accumulation integral reaches a certain value. In order to perform the calculation of the logic of this ECU, the data of the acceleration sensor sampled in the interrupt processing routine generated every predetermined time is sequentially integrated for a predetermined time, and the data of the deceleration cumulative integration is RA.
The data of the oldest acceleration sensor is subtracted, the data of the latest acceleration sensor is added to the integrated value, and the data of the deceleration cumulative integration is updated. By the way, when the deceleration cumulative integration data stored in the RAM changes due to external noise or the like (RAM
It is called a ghost), and this change is checked as follows.

FIG. 2 is a diagram for explaining checking of updating of deceleration cumulative integration stored in a conventional RAM. As shown in the figure, the data of the acceleration sensor 1 is first stored in the RAM.
2, 3, 4, 5 and the data SUM of the deceleration cumulative integration
The value and the address data of the pointer indicating the address where the oldest data is replaced with the latest data and stored are stored.
In the processing of the data in the RAM, the oldest data at the address indicated by the data pointer is subtracted from the SUM value, the latest data is added to the SUM value, and the RA of the address indicated by the pointer is calculated.
The latest data is stored in M, and the address data of the pointer is updated. In this way, by adding all the data every time the data of the acceleration sensor is input, it is possible to prevent the processing time from increasing. As mentioned above, the SUM
When the value changes due to external noise or the like, it cannot be restored until the microcomputer is reset. Therefore, the SUM 'value is stored in the RAM, and this data is added to the SUM' value each time the data of the acceleration sensor is input. For example, the SUM 'value is changed every time the interval time of the interval integration of data 1 to 5 elapses. It is replaced by the SUM value and the SUM 'value is cleared. In this way, the SUM value is prevented from changing due to external noise or the like.

[0005]

However, since the collision determination process of the airbag system is performed by the interrupt generated at every predetermined time, the processing time should be as short as possible. There is a problem that the processing time is long in the arithmetic processing, and further, when the SUM 'value and the SUM value do not match, it is impossible to determine which one is abnormal at the time of replacement.

Therefore, in view of the above problems, it is an object of the present invention to provide an air bag collision calculation check device capable of reducing the load of interrupt processing and improving the function of judging an abnormality in the data stored in the RAM. To do.

[0007]

SUMMARY OF THE INVENTION In order to solve the above problems, the present invention provides an airbag collision computing device having the following configuration. In order to deploy the airbag installed in the vehicle, the airbag collision calculation unit that integrates the detected data of deceleration detected by the acceleration sensor and calculates the integrated value to determine the collision Is stored, the oldest detected data is updated to the latest detected data, and the integrated value (SUM value) obtained by integrating all detected data
A storage means for storing is provided. The integration means for performing interrupt processing with a short data processing interval is the integrated value (SUM value)
The oldest detected data is subtracted from and the latest detected data is added. The adding means for performing the main routine processing having a long data processing interval adds all the detected data during a period when the interrupt processing is not performed, and calculates an added value (SUM 'value). The difference forming means calculates a difference between the integrated value (SUM value) and the added value (SUM 'value). The abnormality determining means is used to issue an alarm of abnormality when the integrated value (SUM value) and the added value (SUM 'value) do not match continuously for a certain time due to the difference of the difference forming means.

Further, the abnormality determining means is configured to add the integrated value (SUM value) and the added value (SU) by the difference forming means.
If the difference from the M'value matches the value calculated at the previous time and this time, the integrated value (SUM value) of the storage means may be replaced with the addition value (SUM 'value) at this time. Good. The abnormality determining means stores the storage means when the added value (SUM 'value) does not exceed the ignition determination value for deploying the airbag and does not exceed the integral value (SUM value) the ignition determination value. The integrated value (SUM value) may be replaced with the current addition value (SUM 'value).

[0009]

According to the airbag collision calculation device of the present invention, a plurality of detected data are stored, the oldest detected data is updated to the latest detected data, and the integrated value obtained by integrating all the detected data. (SUM value) is stored. Due to the interrupt processing with a short data processing interval, the integrating means causes the integrated value (S
The oldest detected data is subtracted from the (UM value) and the latest detected data is added. By the main routine processing with a long data processing interval, all the detected data are added during the period when the interrupt processing is not performed, and the added value (SUM 'value) is calculated. Then, the difference between the integrated value (SUM value) and the added value (SUM 'value) is calculated. The integration value (SUM value) and the addition value (SU
If the M'value and the M'value do not match continuously for a certain period of time, an abnormal alarm is issued. Therefore, since the added value (SUM 'value) is not processed by the interrupt, it is possible to reduce the interrupt processing, and thereby the sampling cycle can be speeded up.

If the difference between the integrated value (SUM value) and the added value (SUM 'value) is the same as the value calculated at the previous time and this time, the integrated value (SUM) of the storage means.
By replacing (value) with the current addition value (SUM 'value), the discrimination against garbled RAM can be improved. If the added value (SUM 'value) does not exceed the ignition determination value for deploying the airbag, and the integrated value (SUM value) does not exceed the ignition determination value, the integrated value (SU) of the storage means.
By replacing the M value) with the addition value (SUM 'value) of this time, it is possible to improve the discrimination against garbled RAM.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing an airbag collision computing device according to an embodiment of the present invention. As shown in the figure, the airbag collision calculation device includes an acceleration sensor 1 that detects the deceleration of the vehicle. An amplifier 2 is connected to the acceleration sensor 1 to amplify the detected signal. A clipper 3 is connected to the amplifier 2 in order to set a threshold value on the detected signal. This clipper 3 has an A / D converter 4 (Analog to Digit) for converting an analog signal into digital data.
tal Converter) is connected. The A / D converter 4 is connected to a storage means 5 including a RAM for storing the converted detected data.

FIG. 2 is a diagram for explaining the data stored in the RAM 5 of FIG. As shown in this figure, addresses 1 to
Up to 5, detected data 1 to 5 detected by the acceleration sensor 1 are stored. The address 6 stores an integrated value (SUM) obtained by accumulating deceleration by the integrating means 7 described later. The address 7 stores address data for updating the detected data by the pointer 6 described later.

Next, the RAM 5 is provided with a pointer 6 for designating the address of the detected data to replace the oldest detected data with the latest detected data based on the address data stored therein. The pointer 6 updates the address data in the RAM 6 after the designation. The RAM 5 is connected with an integrating means 7 that integrates the detected data by an interrupt process to form an integrated value (SUM value). The integrator 7 successively subtracts the oldest detected data pointed by the pointer 6 from the SUM value and adds the latest detected data to form a SUM value. The SUM of the address 6 of the RAM 5 is generated according to the formed SUM value.
The value is updated. Then, the integrating means 7 forms an SUM value by interrupt processing, but sets an interrupt flag prior to the interrupt.

Further, there is provided an adding means 8 for forming an added value (SUM ') for adding all the detected data 1 to 5 in the RAM 5, and this addition is processed by the main routine. According to the interrupt flag, the interrupt is generated while all the detected data 1 to 5 are added, and the detected data is updated by the instruction of the pointer 6, and the added value SUM ′ value is obtained by the integrating means 7. S which is the integrated value
Prevents a discrepancy with the UM value. That is, the interrupt flag is cleared before the calculation in the main routine process is started, and it is checked by the interrupt flag whether the interrupt process is generated after the addition in the main routine process is completed. If the interrupt flag is cleared, the SUM value and the SUM 'value match, and if the interrupt flag is set, it is determined that they do not match, and the addition is performed again.

The addition means 8 is provided with an abnormality determination means 10 for determining an abnormality and turning on the warning lamp 11 when the disagreements continuously occur for a predetermined time or more. Further, the SUM value from the adding means 8 and the SU from the RAM 5
A difference forming means 9 is provided which takes the difference from the M ′ value. The abnormality determining means 10 connected to the difference forming means 9 detects the SUM value and the S
When the UM 'value and the UM' value do not match, the difference is stored, and when the difference obtained by checking each cycle of the main routine processing thereafter is the same, the SUM value of the RAM 5 changes (R
AM garbled). When the difference determination means 10 determines that the difference is the same, the SUM ′ value of the addition means 8 is replaced with the SUM value stored in the RAM 5. Since this replacement is performed in the interrupt processing, if there is this judgment, the abnormality judging means 10 sets a replacement flag. If this difference is not the same, as a general rule, the change (R
It is determined that the data is AM) and the replacement is not performed.

However, even if they do not match, if SUM 'value <ignition determination value and SUM value ≧ ignition determination value, the replacement is performed. Next, the integrating means 7 is provided with a squib determining means 12 for determining the deployment of the airbag. The squib determining means 12 determines that the airbag should be deployed if SUM value ≧ ignition determination value. The deployment is stopped by the condition of'value <ignition judgment value.

Next, a series of operations of the airbag collision calculation device will be described. FIG. 3 is a flow chart for explaining the interrupt processing operation in the configuration of FIG. The interrupt process shown in this figure is performed, for example, every 0.5 ms. In step S1, it is determined whether the replacement flag of the abnormality determining means 10 is set to Hi. If this determination is "NO", the flow proceeds to step S4 described below.

In step S2, it is determined whether SUM = 0. If this determination is "NO", step S4 described later
Proceed to. In step S3, the above determination is "YES".
If so, the SUM value in RAM 5 is replaced with the SUM 'value. In step S4, the replacement flag of the abnormality determination means 10 is cleared.

In step S5, the detected data of the acceleration sensor 1 is input. In step S6, the interrupt flag of the integrating means 7 is set to Hi. Step S7
At the integrating means 7, the oldest detected data of the RAM 5 is read from the address designated by the pointer 6, the SUM value of the RAM 5 is read, and the oldest detected data is subtracted from the SUM value.

In step S8, the latest detected data is stored at the address designated by the pointer 6 instead of the oldest detected data in the RAM 5. In step S9, the integrating means 7 reads the latest detected data from the RAM 5 into the SUM value and adds the latest detected data to the SUM value. In step S10, the address data of the pointer 6 is updated to the address data of the oldest detected data.

FIG. 4 is a flow chart for explaining the processing operation of the main routine in the configuration of FIG. The main routine process shown in this figure is performed, for example, every 10 ms. In step S11, the interrupt flag of the integrating means 7 is cleared. In step S12, the addition means 8
Then, the SUM 'value, which is the added value of all the detected data 1 to 5 in the RAM 5, is calculated.

At step S13, the integrated value SUM calculated by the integrating means 7 is set as SUMM. In step S14, it is determined whether the interrupt flag is set by the integrating means 7. This judgment is "YES"
If the interrupt flag is set, the process returns to step S11 and the above procedure is repeated.

In step S15, the above judgment is "N".
If "O" and the interrupt flag remains cleared, it is determined whether SUMM-SUM '= 0 holds. In step S16, the above determination is “YES”
Then, if the SUM value and the SUM 'value match, the count CNT is set to "0". In step S17, DSUM, which is the difference between SUMM and SUM ', is set to "0".
Set to.

In step S18, CNT ≧ 1s
(Second) is established. In step S19, if the above determination is “NO” and CNT ≧ 1 s (seconds), C
It is determined whether NT = 0 holds. This judgment is "NO"
If CNT = 0 is satisfied, the processing ends. Step S2
0, the above judgment is “YES”, and the above formula CNT =
If 0 holds, the warning lamp 11 is turned off (OF
F)

In step S21, step S15
If the judgment is SUMM-SUM '≠ 0, CNT is incremented by "1". In step S22, DSUM = SU
It is determined whether MM-SUM 'holds. Step S2
3, the above determination is “NO” and the above equation DSUM ≠ S
If it is UMM-SUM ', it is determined whether or not SUM'<ignition determination value holds. If this determination is “NO” and SUM ′ ≧ ignition determination value, the process proceeds to step S25 described later.

In step S24, the above judgment is "Y.
In ES ", it is determined whether SUM '<SUMM> if ignition determination value> ignition determination value holds. In step S25,
If the above judgment is “NO” and SUMM ≦ ignition judgment value, SU
Let MM-SUM 'be DSUM. After that, step S1
The main routine goes around via 8, 19, and 20.

In step S26, step S18
If the determination is “YES” and CNT ≧ 1s, the warning lamp 11 is turned on. In step S27, if the determination in step S24 is "YES" and SUMM> ignition determination value, the abnormality determination means 10 prepares for SUM replacement. Furthermore, the above determination in step S22 is “YES”.
If DSUM = SUMM-SUM 'holds in step S1, the abnormality determination means 10 similarly prepares for SUM replacement. Thereafter, steps S17, 18, 19 and end processing are performed. The SUM replacement preparation will be described below.

FIG. 5 is a flow chart for explaining the processing of the SUM value replacement preparation in step S27 of FIG. In step S30, the interrupt flag Hi in the integrating means 7 is cleared by the adding means 8. In step S31, the addition unit 8 calculates the SUM 'value, which is the added value of all the detected data 1 to 5 in the RAM 5.

In step S32, the adding means 8 is prohibited from interrupting the integrating means 7. In step S33, it is determined whether the interrupt flag Hi in the integrating means 7 is set. In step S34, when the determination is "YES" and the interrupt flag Hi is set, the interrupt is permitted, the process returns to step S30, and the above procedure is repeated.

In step S35, the above judgment is "N".
If the interrupt flag Hi is cleared by "O", the replacement flag Hi is set. In step S36, interruption is permitted. In this way, the interrupts are specifically prohibited in steps S34 and S35 in order to prevent the processing from being complicated.

[0031]

As described above, according to the present invention, a plurality of detected data are stored, the oldest detected data is updated to the latest detected data, and the integration is performed by integrating all the detected data. A value (SUM value) is stored, and the integration unit performs the integrated value (SUM
The oldest detected data is subtracted from (value) and the latest detected data is added. By the main routine processing with a long data processing interval, all the detected data are added during the period when there is no interrupt processing, and the added value is calculated. Then, the difference between the integrated value and the added value is calculated. When the integrated value and the added value do not match continuously for a certain period of time due to the difference in the difference forming means, an abnormal alarm is issued, so that interrupt processing can be reduced and the sampling cycle can be speeded up. If the difference between the value and the added value matches the value calculated by the previous time and this time, the integrated value of the storage means is replaced with the added value of this time, so that the discrimination against garbled RAM can be improved and the added value can be When the ignition determination value for deploying the airbag is not exceeded and the integrated value ignition determination value is exceeded, the integrated value of the storage means is replaced with the addition value of this time, so that discrimination against garbled RAM can be improved. .

[Brief description of drawings]

FIG. 1 is a diagram showing an airbag collision calculation device according to an embodiment of the present invention.

FIG. 2 is a diagram illustrating data stored in a RAM 5 of FIG.

FIG. 3 is a diagram illustrating an interrupt processing operation in the configuration of FIG.

FIG. 4 is a diagram illustrating a processing operation of a main routine in the configuration of FIG.

FIG. 5 is a flowchart illustrating a SUM value replacement preparation process in step S27 of FIG.

FIG. 6 is a diagram illustrating data stored in a conventional RAM.

[Explanation of symbols]

 1 ... Acceleration sensor 5 ... RAM 6 ... Pointer 7 ... Integrating means 8 ... Addition means 9 ... Difference forming means 10 ... Abnormality determining means 11 ... Weaning lamp

Claims (3)

[Claims] 1. An airbag collision calculation device for determining a collision based on an integral value obtained by integrating detected data of deceleration detected by an acceleration sensor (1) in order to deploy an airbag installed in a vehicle. In the storage means (5), a plurality of the detected data are stored, the oldest detected data is updated to the latest detected data, and an integrated value (SUM value) obtained by integrating all the detected data is stored. And the integrated value (S
(UM value), the integration means (7) for subtracting the oldest detected data and adding the latest detected data, and all the detected data during the period when there is no interrupt processing due to the main routine processing with a long data processing interval. An addition means (8) for adding and calculating an addition value (SUM 'value), and a difference forming means (9) for calculating a difference between the integration value (SUM value) and the addition value (SUM' value), Due to the difference of the difference forming means (9), the integrated value (SUM
An air bag collision computing device, comprising: abnormality determination means (10) for issuing an alarm of abnormality when the value) and the added value (SUM 'value) do not match continuously for a certain period of time. 2. The abnormality determining means (10) calculates the difference between the integrated value (SUM value) and the added value (SUM 'value) by the difference forming means (9) between the previous time and this time. And the integrated value of the storage means (5) (S
The airbag collision calculation device according to claim 1, wherein the UM value) is replaced with a current addition value (SUM 'value). 3. The abnormality determining means (10) is configured such that the added value (SUM 'value) does not exceed an ignition determination value for deploying an airbag, and the integrated value (SUM value) does not exceed the ignition determination value. 2. The airbag collision calculation device according to claim 1, wherein, when it exceeds, the integrated value (SUM value) of the storage means (5) is replaced with the current added value (SUM 'value).