JPH07112804B2 - Vehicle occupant protection device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle occupant protection device for protecting an occupant in the event of a vehicle collision.

[Conventional technology]

A conventional vehicle occupant protection device is, for example, Japanese Patent Laid-Open No. 49-55.
There is one such as shown in Japanese Patent No. 031. That is, in this publication, a signal waveform of a certain level or more is extracted from the acceleration signal detected by the acceleration sensor, and the extracted signal waveform is integrated by an integrator to compare whether the integrated output exceeds a predetermined level. Configuration to protect the occupant by driving the ignition device such as the airbag system, which is the body of the occupant protection device, to inflate the airbag and tightening the seat belt when a predetermined level is exceeded. belongs to.

[Problems to be Solved by the Invention]

However, in such a conventional vehicle occupant protection device, since the collision waveform from the acceleration sensor is completely double-integrated, drifts of the acceleration sensor and the like are integrated and accumulated. There is a problem that negative acceleration signals and the like during sudden braking when the vehicle is running are integrated and accumulated, and as a result, the airbag system may malfunction.

The present invention has been made to solve the above problems, and integrates drift of an acceleration sensor or the like,
An object of the present invention is to obtain a vehicle occupant protection device which integrates a negative acceleration signal of a sudden braking during traveling of the vehicle to prevent the occupant protection device main body from malfunctioning.

[Means for Solving the Problems]

The vehicle occupant protection system according to the present invention includes a predicting unit that calculates a predicted value such as a displacement and speed of an occupant with respect to a seat after a predetermined time based on an output from an acceleration sensor, and an output from the predicting unit exceeds a threshold value. A threshold value circuit that outputs a trigger signal when the noise sensor is present, and noise removing means that removes noise superimposed on the output from the acceleration sensor by being inserted in the signal line between the acceleration sensor and the threshold value circuit,
The occupant protection device main body operates based on the trigger signal output from the threshold circuit.

[Work]

The vehicle occupant protection device according to the present invention removes high-frequency noise superimposed on the acceleration signal detected by the acceleration sensor when the vehicle collides or travels on a rough road, and
The detection output is incompletely integrated, and when the integrated output exceeds a predetermined threshold value, a trigger signal is output to operate the passenger protection device main body.

〔Example〕

 Hereinafter, the present invention will be described in detail with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of the present invention.

First, the configuration will be described. In the figure, 1 is an acceleration sensor that detects a change in acceleration due to a vehicle collision and outputs the state as an analog signal, and 2 has a time constant T ₁ and is output from the acceleration sensor 1. that the first incomplete integrating circuit for integrating the analog signal, along with 3 time with a constant T _2, first
The second incomplete integration circuit 4 having the same function as that of the incomplete integration circuit 2 and incompletely integrating the incomplete integration output from the first incomplete integration circuit 2 again has the first coefficient in the detection output of the acceleration sensor 1. A first coefficient circuit 5 including a first attenuator for adding a second coefficient circuit 5 including a second attenuator.
Adds a second coefficient to the integrated output of the first incomplete integration circuit 2. The damping rate of the first engagement circuit 4 is 1/2 the square of the damping rate of the second coefficient circuit 5. Also, the attenuation ratio of the second coefficient circuit 5 is equal to the time t _f required from the supply of the ignition current to the ignition apparatus described later until the inflation of the airbag is completed. 6 is a first moving average circuit which is a noise removing means, 7 is a second moving average circuit which is a noise removing means,
When the moving average time of the first and second moving averaging circuits 6 and 7 and t _a, that is averaged in _{(t f -t a) / 2~} (t f + t a) / 2 data desired . Therefore, the second coefficient circuit 5
An attenuator the attenuation factor constituting the t _f + (1/2) in t _a, also the attenuator attenuation factor constituting the first coefficient circuit 4 (1/2) {t _f
+ (1/2) is set to t _a} ^2. Reference numeral 8 denotes an adder circuit, which adds the respective outputs of the second incomplete integration circuit 3, the first moving average circuit 6, and the second moving average circuit 7. Reference numeral 9 is a threshold value comparison circuit that switches the output level to, for example, a high level when the added output from the addition circuit 8 exceeds a predetermined threshold value, 10 is a drive circuit, and 11 is an ignition device which is the body of the occupant protection device. Operates an airbag, for example, based on the output of the drive circuit 10.

Next, the operation will be described.

Various accelerations act on the vehicle as the vehicle travels.
Now, when the acceleration sensor 1 detects the acceleration a (t) acting in the front-rear direction of the vehicle due to, for example, a collision when the vehicle is traveling at a constant speed V ₀ , the occupant's head moves at a constant speed V ₀ . While being thrown out, the acceleration a at that time
(T) also acts on the occupant. As a result, the occupant's head moves at a certain relative speed with respect to the vehicle, that is, V (t) (= ∫a
(T) dt) starts moving. On the other hand, the output a (t) of the acceleration sensor 1 at that time is integrated by the first incomplete integration circuit 2. In addition, if the position is set to the initial position just before the collision by moving the head, x
It moves forward by (t) (= ∫V (t) dt). This displacement x (t) is obtained by integrating the output of the first incomplete integration circuit 2 by the second incomplete integration circuit 3, and the displacement amount of the occupant's head in real time is calculated. Next, the output V (t) of the first incomplete integration circuit 2 is output by the second coefficient circuit 5. Is weighted, That is, the amount of displacement during the time t _f is obtained. Furthermore, the output a (t) of the acceleration sensor 1 is output by the first coefficient circuit 4. Only weighted, That is, the amount of displacement during the time t _f is obtained. These outputs are noise-removed by the moving average circuits 6 and 7, and then added by the adder circuit 8, Is required. In other words, this is the predicted value x of the position of the occupant's head (t + t _f) is determined after t _f time from the present time t. This predicted value is supplied to the threshold circuit 9, and when the position of the occupant's head deviates from the initial position 0 by x, that is, the time
At t ₁ , x (t + t _f ) is determined to have exceeded the threshold value x of the threshold circuit 9, and an ignition current is supplied to the ignition device 11 to activate the airbag and protect the occupant. That is, if the position for operating the airbag or the like is set to a position separated from the initial position by x, as shown by x (t), a time t that is t _f earlier than the time t _{2 at} which the head actually reaches x. It turns out to work for ₁ .

Although the moving averaging circuit is used as the noise removing means in the above embodiment, a low pass filter may be connected to the subsequent stage of the adding circuit 8. In this case time corresponding to the moving average time t _a of the moving averaging adder circuit of the first figure corresponds to the time constant.

In the above embodiment, the first and second incomplete integration circuits are used.
It goes without saying that the integral constants T ₁ and T ₂ of _{2 and 3} may be the same or different.

Further, in the above-mentioned embodiment, the ignition current is supplied to the ignition device 11 to deploy the airbag, but it goes without saying that the seat belt tensioning device may be activated.

Furthermore, although the first and second coefficient circuits have been described as attenuators in the above embodiment, it goes without saying that they may be increasers depending on the magnitude of the input signal.

〔The invention's effect〕

As described above, according to the present invention, a predicting means for calculating the predicted value of the displacement / speed of the occupant with respect to the seat after a predetermined time based on the output from the acceleration sensor, and the predicting means A threshold circuit that outputs a trigger signal when the output exceeds the threshold, and noise that is inserted in the signal line between the acceleration sensor and the threshold circuit and that is superimposed on the output from the acceleration sensor is removed. Since the vehicle occupant protection device is provided with the noise removal means and the occupant protection device main body that operates based on the trigger signal output from the threshold circuit, the occupant protection device is affected by noise such as drift and acceleration sensor output due to sudden braking. The effect that the main body does not malfunction can be obtained.

[Brief description of drawings]

FIG. 1 is a block diagram showing a vehicle occupant protection system according to an embodiment of the present invention. 1 ... Acceleration sensor, 2 ... First incomplete integration circuit, 3 ...
... second incomplete integration circuit, 4 ... first coefficient circuit, 5 ... second coefficient circuit, 6,7,12 ... noise removing means, 8 ... adding circuit, 9 ... threshold circuit, 11 ... Occupant protection device body.

 ─────────────────────────────────────────────────── ─── Continuation of front page (56) References JP-A-49-55031 (JP, A) JP-A-3-253441 (JP, A) Special table Sho-63-503551 (JP, A) International publication 90-9298 (WO, A)

Claims (1)

[Claims] 1. A predicted value such as a displacement / relative speed of a body of an occupant with respect to a seat after a predetermined time with respect to a vehicle is calculated based on an output from an acceleration sensor (1) for detecting an acceleration of the vehicle. A prediction means including a first incomplete integration circuit (2), a second incomplete integration circuit (3), a first coefficient circuit (4), a second coefficient circuit (5), and an addition circuit (8), and this prediction. The output from the means is inserted in a signal line between a threshold circuit (9) that outputs a trigger signal when the output exceeds a predetermined threshold, and the acceleration sensor (1) and the threshold circuit (9). A first moving average circuit (6) for removing noise superimposed on the output from the acceleration sensor (1), a second
A vehicle occupant protection device comprising: a noise removing means composed of a moving averaging circuit (7); and an occupant protection device body (11) which operates based on a trigger signal output from the threshold circuit.