JPH07112803B2 - 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 the level exceeds the predetermined level. belongs to.

[Problems to be Solved by the Invention] However, in such a conventional vehicle occupant protection device, attention is paid only to the integrated value of the output signal waveform from the acceleration sensor, and the occupant is in a dangerous state due to aging. Since it is configured to judge whether or not it is a collision accident by using a complicated logical means, the behavior of the occupant after the vehicle collision is not grasped, and further, the occupant protection device for the vehicle causes an operation delay, which is an optimal condition. In order to obtain the operation timing, a large number of acceleration waveforms at the time of collision have to be collected to compose a complicated logic, which causes a problem that it takes a lot of development time. In addition, there has been a problem that a large number of vehicles have to be subjected to a collision test in order to collect the acceleration waveform, which requires a lot of labor and funds.

The present invention has been made to solve the above problems, and predicts the movement of the upper body of a human head or the like, and operates the occupant protection device main body reliably and accurately so as to operate the occupant. The purpose is to obtain a protective device.

[Means for Solving the Problems]

A vehicle occupant protection system according to the present invention is a displacement amount measuring means for predicting a displacement amount of an occupant's upper body after a predetermined time based on an acceleration signal, and an output from the displacement amount predicting means exceeds a first threshold value. Output from the displacement speed predicting means, a first comparing circuit that outputs a first determination signal when the vehicle speed is high, a displacement speed predicting means that predicts a displacement speed of the upper body of the occupant after a predetermined time based on the acceleration signal. When it exceeds the second threshold value, the second comparison circuit that outputs the second determination signal and the first and second determination signals from the first and second comparison circuits are ANDed to obtain the first and second determination signals. (2) A gate circuit that outputs a trigger signal to operate the main body of the occupant protection device when the levels of the determination signals match.

[Work]

The vehicle occupant protection device in this invention predicts the displacement amount of the occupant's upper body after a predetermined time based on the acceleration signal, and predicts the speed of the occupant's upper body after a predetermined time based on the acceleration signal, A first determination signal when the displacement amount prediction value from the displacement amount prediction means exceeds the first threshold value, and a second determination signal when the displacement speed prediction value from the displacement speed prediction means exceeds the second threshold value. When a logical product is obtained, a trigger signal is output to operate the main body of the occupant protection device to protect the occupant in advance.

〔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 collision of a vehicle and outputs the state as an analog signal a (t), 2 has a time constant T ₁ , and the acceleration sensor Analog signal a output from 1
The first incomplete integrator circuit 3 for integrating (t) has the time constant T ₂ and has the same function as the first incomplete integrator circuit 2, and the incomplete integrator output from the first incomplete integrator circuit 2. v
A second incomplete integration circuit for incompletely integrating (t) again, 4 is a first coefficient circuit including a first attenuator for adding a first coefficient to the detection output of the acceleration sensor 1, and 5 has an attenuation rate of K. Second
In the second coefficient circuit including an attenuator, the second coefficient circuit 5 outputs the second incomplete integral output v (t) of the first incomplete integral circuit 2 to the second incomplete integral output v (t).
Add a coefficient. The attenuation rate of the first coefficient circuit 4 is 1/2 the square of the attenuation rate K of the second coefficient circuit 5. The damping rate K is equal to the time t _d required after the ignition current is supplied to the ignition device 13 described later until the inflation of the airbag is completed. Reference numeral 6 denotes a first addition circuit, which adds the output x (t) from the second incomplete integration circuit 3, the output from the first coefficient circuit 4 and the output from the second coefficient circuit 5. Then, the predicted positional transition value as the movement amount is output. Reference numeral 7 denotes a first comparison circuit that outputs a first determination signal when the output that is the movement amount predicted value exceeds a first threshold value.
The first determination signal from the comparison circuit 7 is supplied to one input of the AND gate 8. Reference numeral 9 is a third coefficient circuit including a third attenuator having an attenuation factor of G. The third coefficient circuit 9 adds the third coefficient to the detection output of the acceleration sensor 1. Reference numeral 10 is a second addition circuit for adding the incomplete integration output v (t) of the first incomplete integration circuit 2 and the output from the third coefficient circuit 9, and the second addition circuit 10 predicts the displacement speed as the displacement speed. Output the value. Reference numeral 11 is a second comparison circuit that outputs a second determination signal when the output that is the displacement velocity predicted value exceeds the second threshold value. The second determination signal from the second comparison circuit 11 is the other of the AND gates 8. Supplied on input. Reference numeral 12 is a drive circuit that operates based on the output signal of the AND gate 8. Reference numeral 13 is an ignition device that is the body of the occupant protection device. The ignition device 13 operates, for example, an airbag based on the output of the drive circuit 12.

Next, the operation will be described.

Various accelerations act on the vehicle as the vehicle travels.
Now, for example by a collision when traveling at a vehicle constant speed v _0, the acceleration a which acts in the longitudinal direction of the vehicle, as shown in FIG. 2 (a) (t) is detected by the acceleration sensor 1 , The head of the occupant is thrown out at a constant velocity v ₀ , while the acceleration a (t) at that time also acts on the occupant. Thereby the head is at a certain relative speed with respect to the vehicle, ie v
It starts to move at (t) (= ∫a (t) dt). 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. Further, when the position immediately before the collision is set to the initial position 0 by moving the head, the head is displaced forward by x (t) (= ∫v (t) dt) with the passage of time from that position. The 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 x (t) of the occupant's head in real time is calculated. Next, the first incomplete integration circuit second output v (t) is t _d is weighted by the second coefficient circuit 5, the amount v (t) × t _d to be displaced between the t _d times are calculated. Further, the output a (t) of the acceleration sensor 1 is 1 / 2t _d ² by the first coefficient circuit 4.
Amount 1 / 2a (t) that is weighted only and is displaced during t _d time
× t _d ² is required. These outputs are added by the first addition circuit 6, and x (t) + v (t) × t _d + 1 / 2a (t)
× t _d ² is required. That is, this is from the present t to t _d
Predicted displacement amount x, which is the position of the occupant's head after time
(T + t _d ) is required. This predicted displacement amount is supplied to the first comparison circuit 7, and when the position of the occupant's head deviates from the initial position 0 by x in FIG. 2B, that is, at time t ₁
When the displacement amount predicted value x (t + t _d ) exceeds the first threshold value x of the first comparison circuit 7, the first determination signal is the AND gate 8
Is supplied to one of the inputs. In addition, the acceleration signal a
(T) is weighted by t _d by the third coefficient circuit 9,
The output of the third coefficient circuit 9 and the integrated output V (t) of the first integrating circuit 2 are added by the second adding circuit 10 to output a displacement speed prediction value which is a speed prediction value. Then, when the displacement velocity predicted value from the second addition circuit 10 exceeds the second threshold value of the second comparison circuit 11, the second determination signal is supplied to the other input of the AND gate 8. Thus, the AND gate 8 outputs the trigger signal by simultaneously supplying the respective determination signals to both inputs of the AND gate 8. Therefore, the drive circuit 12 operates to supply an ignition current to the ignition device 13, activate the airbag, and protect the occupant. That is, in FIG. 2 (b), when the displacement amount for actuating the airbag or the like is set at a position separated from the initial position by x, as shown by x (t), the time t at which the head position actually reaches x is set. It can be seen that the airbag activates at time t ₁ , which is t _d faster than ₂ .

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

Further, in the above-described embodiment, the explanation was made such that the ignition current is supplied to the ignition device 13 to deploy the airbag, but it goes without saying that the seat belt tensioning device may be operated.

Furthermore, in the above embodiment, the first and second coefficient circuits 4,
Although 5 is described as an attenuator, it goes without saying that it may be an amplifier depending on the magnitude of the input signal.

〔The invention's effect〕

As described above, according to the present invention, the configuration is such that the displacement amount measuring means for predicting the displacement amount of the body of the occupant after a predetermined time based on the acceleration signal and the output from the displacement amount predicting means are A first comparison circuit that outputs a first determination signal when the threshold value is exceeded, a displacement speed prediction unit that predicts the displacement speed of the upper body of the occupant after a predetermined time based on the acceleration signal, and the displacement speed prediction. A second comparison circuit that outputs a second determination signal when the output from the means exceeds a second threshold value, and the first and second determination signals from the first and second comparison circuits are ANDed, and Since the vehicle occupant protection device is provided with the gate circuit that outputs the trigger signal when the levels of the first and second determination signals match to operate the occupant protection device main body, the movement of the upper body such as a human head is prevented. Predict and be sure,
Further, it is possible to obtain the effect that the occupant protection device main body can be operated at an accurate timing.

[Brief description of drawings]

FIG. 1 is a block diagram showing an occupant protection device for a vehicle according to an embodiment of the present invention, and FIGS. 2 (a) and 2 (b) are output waveform diagrams showing a detection output of an acceleration sensor at the time of a collision and a displacement amount. FIG. 1 ... Acceleration sensor, 2 ... First incomplete integration circuit, 3 ...
2nd incomplete integration circuit, 4 ... 1st coefficient circuit, 5 ... 2nd coefficient circuit, 6 ... 1st addition circuit, 7 ... 1st comparison circuit, 8 ... AND gate, 9 ... 3 coefficient circuit, 10 ...
Second adder circuit, 11 ... Second comparison circuit, 13 ... Main body of passenger protection device.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-49-55031 (JP, A) JP-A-62-128854 (JP, A) International publication 90-9298 (WO, A)

Claims (1)

[Claims] 1. Displacement amount predicting means (2,3,4,5,6) for predicting a displacement amount of an occupant's upper body after a predetermined time based on an acceleration signal.
And a first comparison circuit (7) for outputting a first determination signal when the output from the displacement amount prediction means exceeds a first threshold value,
Displacement speed prediction means (2,9,1) for predicting the displacement speed of the occupant's upper body after the predetermined time based on the acceleration signal.
0) and a second comparison circuit (1 which outputs a second determination signal when the output from the displacement velocity prediction means exceeds a second threshold value.
1) and the first and second determination signals from the first and second comparison circuits are ANDed, and when the levels of the first and second determination signals match, a trigger signal is output to output the occupant protection device. A vehicle occupant protection device comprising a gate circuit (8) for operating a main body (13).