JPH03121951A - Air bag starting control device - Google Patents

Abstract

PURPOSE:To correspond to various kinds of vehicles by storing speed change data at the time of collision previously as a collision judging table, and comparing this with the integrated value of an acceleration signal at the collision generated time to determine the air bag expanding time. CONSTITUTION:In a control circuit 2, speed change data at the time of collision corresponding to the elapsed time from the collision and the vehicle speed is previously stored as a collision judging table 31 into a storage circuit 3. A signal from an acceleration sensor 1 is then inputted, and after its high frequency component being removed by an analog filter 21, subjected to sampling at a sampling circuit 22. When the specified value (for instance 1.2G) or more is judged at an acceleration judging circuit 23, the integral operation of the acceleration signal is started at an arithmetic circuit 24. After comparative operation between this integrated value and the collision judging table 31, an air bag signal is outputted under the specified condition. The collision judging table can be thus easily adapted to various kinds of vehicles by altering it according to the type of the vehicle.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an airbag activation control device that protects a passenger in the event of a collision of a vehicle such as an automobile.

[Conventional technology]

When an impact is applied to the vehicle body due to a collision, the collision protection system detects this and issues an airbag activation signal, which instantly activates the airbag activation device and inflates the airbag inside the vehicle. It is being

If such a device is activated only by the acceleration signal at the time of a vehicle collision, the airbag device will be activated erroneously even if the acceleration detection unit is hit by an impact (hammering) that would not cause an accident. May be dangerous. To avoid this, for example, as disclosed in Japanese Patent Publication No. 59-8574, the activation prediction level is set lower than the airbag activation level, and when the integral value of the acceleration signal due to impact reaches the above prediction level. The above malfunction is avoided by lengthening the reset pulse period of the integrating means and at the same time proportionally changing the activation level.

[Problem to be solved by the invention]

The above conventional technology solves the problem of malfunctions caused by impacts other than collisions, but does not take into consideration the issue of activating the airbag at the optimum airbag deployment time for the passenger (driver). do not have.

SUMMARY OF THE INVENTION An object of the present invention is to provide an airbag activation control device that is activated only in response to a collision and that activates the airbag at an optimal airbag deployment time for the occupant.

[Means to solve the problem]

The above purpose is to provide a storage means for storing data representing a change in speed at the time of a collision according to the elapsed time from the collision and the speed of the vehicle, a calculation means for performing an integral calculation on an acceleration signal, and an integral calculation value of the acceleration signal. This is achieved by providing means for determining the airbag deployment time by comparing the data with the data stored in the storage means.

[Effect]

The change in acceleration and the stored value are compared over time, and the airbag is activated when the integral value of acceleration, that is, the change in speed exceeds a certain level. Record? By changing the memory contents of the means according to the vehicle to which it is applied, the airbag can be deployed optimally for the characteristics of the vehicle.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing a schematic configuration of an embodiment of an airbag activation control device according to the present invention, where ■ is an acceleration sensor, 2 is a control circuit, 3 is a memory circuit, 21 is an analog filter, and 22 is a sampling 23 is an acceleration judgment circuit; 24 is an arithmetic circuit (integrator circuit); and 31 is a collision judgment table stored in the memory circuit 3.

In the figure, an acceleration sensor 1 is a means for sensing the acceleration of the vehicle, which is an accelerometer made up of a piezoelectric element, etc., and a control circuit 2 is a means for supplying an activation signal to an airbag activation circuit, and a collision judgment/airbag deployment signal. (Start signal) sending timing program is also stored. Further, the storage circuit 3 is a means for storing in advance data (collision determination table) on speed changes at the time of collision according to the elapsed time from the collision and the speed of the vehicle.

The analog filter 21 is for removing high frequency components such as noise coming from the acceleration sensor 1 in order to extract only large components of collision acceleration. The output of the acceleration sensor 1 that has passed through the analog filter 21 is sampled in a sampling circuit 22 . The sampling rate is, for example, 1 m5 ec (sampling frequency 1 kHz), and the signal from the sensor 1 is taken in as a vehicle body state signal every 1 m5 ec.

The signal sampled by the sampling circuit 22 is supplied to the acceleration determination circuit 23, where the acceleration is determined.

This acceleration judgment circuit 23 is set to judge acceleration in 51 steps, for example, in units of 0.40 (G is acceleration), and can detect up to 20.4G. Note that if it exceeds 20.4G, it remains at 20.4G.

When the input acceleration signal reaches a set value of the acceleration judgment circuit 23, for example, 1.2G (), a trigger signal is given to the calculation circuit 24 to start the integral calculation for the acceleration signal from that point.

The calculation circuit 24 performs an integral calculation on the input data, calculates the contents of the collision determination table 31 stored in the storage circuit 3, and the integral value of the input data, and outputs an airbag deployment signal under predetermined conditions.

FIG. 2 is an explanatory diagram of the meaning of the collision judgment table, in which 201 is a steering wheel, 202 is an airbag, 203 is a driver, and 204 is a seat.

FIG. 3 is a graph of vehicle speed and speed change determined through experiments.

From the speed change curve shown in FIG. 3, the relationship between the passage of time and the speed difference ΔV at Ton can be determined. If this is stored as a table, the airbag deployment signal can be sent out at the designed time. By making this table changeable, the deployment signal ON transmission time can be set later or earlier.

The settings in the table 31 are based on factors such as the position of the steering wheel 201, the position of the seat 204, the seating posture of the driver 203, the deployment length and deployment time of the airbag 202, and the shock absorption method 9 at the time of a collision. , when these factors are specified, the settings in the table are changed to optimally control the timing of airbag deployment. Here, the time required for the airbag 202 to deploy in FIG. 2 is Tf, the time required for the distance between the driver's face and the airbag deployment end surface, that is, the distance the driver's face moves (for example, 125 mm), Tb,
T is the sensor signal sending time.

When n, the time T for turning on the airbag deployment signal
on is set as Ton=Tb-Tf.

In the graph of Figure 3, the airbag deployment time is 3
Assuming that the vehicle speed is 10 miles/hour (1
6km/H), 20'? Ile/hour (32km/H),
In 3 cases of 30 miles/hour (48km/H), the above 1.
Ton against the time Tb required to move 25 mm was plotted.

If Ton is known in advance, the relationship between the passage of time and the speed difference ΔV at Ton can be determined from the speed change curve shown in FIG. 3 due to the initial speed of the collision.

If this is stored as a table, the airbag deployment signal can be sent at the designed time as described above.
By making the table changeable, the deployment signal on transmission time can be set arbitrarily.

As mentioned above, the collision judgment table 31 is a table that combines the elapsed time from the time when the trigger G is reached and the speed change (ΔV) required to turn on the trigger G corresponding to the elapsed time. If the acceleration calculation result from the time when G is reached is larger than the table value after the same time has elapsed, the first stage is turned on, and if it is smaller than the table value, the calculation is continued. That is, if the calculation result≧table value, the first stage ON signal is set.

Next, when the ON signal state is reached in the first stage and the final acceleration value is, for example, 2G or more, the second stage is set as the ON signal, and the airbag deployment signal is turned ON and sent to the airbag actuating device.

FIG. 4 is an explanatory diagram of the relationship between the first stage and the second stage described above.
The reason for having a two-step process in which the acceleration waveform ends at exactly that point and does not affect the driver is that even if ■ is large, it is recognized that the acceleration value is small. This is to distinguish it from a collision that requires airbag deployment.

In addition, in the following cases, the arithmetic circuit is reset as shown below.

Figures 5, 6, and 7 are explanatory diagrams of the operation of the arithmetic circuit, and as shown in Figure 5, after reaching trigger G and starting calculation, it becomes less than 1990 again, and it continues. then 5
If it continues for more than msec, the arithmetic operation is reset.

On the other hand, as shown in FIG. 6, even if the value becomes less than 1990 again after starting the calculation, it becomes less than 1.5 m5ec.
When it is 2G or more, the calculation is continued.

As shown in FIG. 7, the arithmetic circuit is also reset if the ON condition is not satisfied even after, for example, 10 Qmsec after the trigger G is reached and the arithmetic operation is started.

Now, in the operation of the arithmetic circuit 24, if the sampled and read acceleration data becomes less than 1990, the absolute value of the table value at that time and the previous time will be deleted from the calculated values up to that time. do.

This is to distinguish between dirt, because when a signal of less than 1990 and less than 5 msec is received, there is a possibility of malfunction due to the local shock (hammering, etc.) to the sensor mentioned above. This eliminates the subtraction effect.

FIG. 8 is an explanatory diagram of the above subtraction operation, in which (a) is a velocity characteristic diagram, (b) is an acceleration characteristic diagram, and (C) is an enlarged diagram of (a).

That is, as shown in (a), if the above-mentioned subtraction is not performed, the speed will remain horizontal, resulting in an on state. Therefore, as shown in an enlarged view in (C), by performing subtraction, the calculated value (integral value) shifts from point A to point B, thereby avoiding malfunction.

Next, a method of calculating speed changes will be explained.

Figures 9 and 10 are explanatory diagrams of the calculation method, where the acceleration data at the time when trigger G is reached (exceeds 1 - trigger G) is INPA (1), and the one before INPA (1) is set as INPA (1). If the data of is INPA (0), then from this data lm
The data after 5 ec becomes I N l) A(1).

The cumulative acceleration value is the cumulative value of INPA (1), INPA
Define three cumulative values of (1-1) and their average values,
SVl, SV2. It is set as SV3.

SVI, SV2. SV3 can be obtained using C as shown below.

SV([) =INPA(1) +5VI(1-1
)(SVl (0) = 0) SV(1) =INPA(1-1)+5V2(I
-1) (SV2(0)=O) SV3(+) = 1/2(SV1(1)→-8shi2(
1)) (SV3 (0) = 0) As shown in Fig. 9, SV3 is approximated to be as close as possible to the area (integral value: speed change) surrounded by the curve.

FIG. 11 is a flowchart for explaining the present invention in detail, and the reference numerals and symbols in the figure do not represent the following contents.

I: The initial value is 0, and when it reaches 1 to Riga G, it becomes 1, and thereafter it is incremented by 1 every time one piece of data is acquired. Time elapsed after calculation start J: Number of times SVI fell below trigger G again
Cumulative value of (mouth: INPA days) SV2 (1):
Cumulative value of INPA (1-1) SV3 (1) +
SV1. Average value N of (1) and 5V (2):
Nth SR of the table ([): Table value when lm5ec has elapsed INPA (1): Acceleration (G) at the time when lm5ec has elapsed In the same figure, (a) is the trigger mode, and I=O in step] , J=O, and read the acceleration (G) (Step 2).

If the read acceleration is 1.2G or more (step 3), set I = I +1 (step 4).

If it is less than 1.2, the acceleration data is saved as INPA (0) (step 5).

After setting I=1+1 in step 4, SVI (1),
Calculate SV2 (1) and SV3 (1) (Step 6) to judge whether ■ exceeds 5 or not Step 7
), if YES, N = [ table values SR(1) and SV
3 (I) (step 8). Determine whether or not SV3≧table value (step 9); if YES, then I N l) determine whether A(1)≧2G (step 10); if YES, turn on the airbag deployment signal. to the actuator (step 11).

(b) and (C) in the same figure are reset modes, and (b)
), determine whether I≧100 according to the output of (a) (2). If YES, reset; if No, continue calculation.

Also, in the continuation mode described later in (C), when the output is 3 4 , J = J +1 is performed (Step 13), and J
≧5, step 14), reset with YES,
Go to subtraction mode with NO.

(d) in the figure is the continuation mode (judgment mode), and (b)
When the decision to continue the operation is made and there is the output of ■, I
= I +1 force (step 15), save acceleration data (step 16), read acceleration (G)
Execute (step 17) and the read acceleration is 1.2
Step 18), Y
Set J=O in ES (step 19) and go to (a) (■).

(e) of the same figure is the subtraction mode, and step 14 of (C)
When No, ■corresponding to the output, the full value SR (1)
, SR(I-1) (step 20), then SV3
(I) -3V3 (1-1)SR(1)-3R(I
-1) Execute l and go to step 21), (a) (■).

As described above, the acceleration of the impact is determined and the airbag is deployed when the vehicle receives an impact of a predetermined value or higher, thereby protecting the passenger at the optimal timing.

〔Effect of the invention〕

As explained above, according to the present invention, the speed change data at the time of the collision according to the elapsed time from the collision and the speed of the vehicle is stored in advance as a collision judgment table in the storage means, and this data and the acceleration at the time of the impact are stored in advance in the storage means. Since the airbag deployment time is determined by comparing the integral value of the signal, by changing the stored contents of the table according to the vehicle model, it can be easily adapted to various types of vehicles, eliminating the drawbacks of the conventional technology. It is possible to provide an airbag activation control device with excellent functionality.

[Brief explanation of drawings]

Fig. 1 is a block diagram showing a schematic configuration of an embodiment of the airbag activation control device according to the present invention, Fig. 2 is an explanatory diagram of the meaning of the collision judgment table in the present invention, and Fig. 3 is an explanatory diagram showing the meaning of the collision judgment table according to the present invention. FIG. 4 is an explanatory diagram of the relationship between the first stage operation and the second stage operation for generating an airbag deployment signal in one embodiment of the present invention, FIG. 5, and FIG. 6 are graphs of vehicle speed and speed change. , FIG. 7 is an explanatory diagram of the operation of the arithmetic circuit in FIG. 1, FIG. 8 is an explanatory diagram of the subtraction operation of the arithmetic circuit in FIG. 1, and FIGS. 9 and 10 are explanatory diagrams of the arithmetic method of the present invention. FIG. 11 is a flowchart illustrating the present invention in detail. 6 1... Acceleration sensor, 2... Control circuit, 3...
...Memory circuit, 21...Analog filter, 22.
... Sampling circuit, 23 ... Acceleration judgment circuit, 24 ... Arithmetic circuit product (integrator circuit), 31 ...
Collision judgment table stored in the memory circuit. ] 7 388- ■

Claims (1)

[Claims] (1) Convert the acceleration of the vehicle at the time of collision into an electrical acceleration signal, calculate this acceleration signal to obtain the calculated value of the speed signal, and when this calculated value reaches a preset activation level or higher, the An airbag activation control device configured to activate an airbag, comprising a storage means storing data on a speed change at the time of the collision according to the time elapsed since the collision and the speed of the vehicle, and the calculated value and the storage means stored in the storage means. a comparison means for comparing the speed change data obtained at each elapsed time; and an activation means for activating the airbag when the calculated value exceeds the speed change data and reaches a certain level of acceleration. An airbag activation control device characterized by comprising: