JPH07112806B2 - 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 whether or not the occupant is in a dangerous state due to a change with time of the integrated value is determined. Since the behavior of the occupant after the vehicle collision is not grasped and the vehicle occupant protection device causes a delay in operation, the acceleration waveform at the time of the collision should be calculated in order to obtain the optimum operation timing. There was a problem that many samples had to be collected and it took 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-mentioned problems, and accurately predicts the movement of the upper body of a human head or the like even if the acceleration waveforms at the time of various collisions are not obtained by experiments, and the body of the occupant protection device is accurately predicted. It is an object of the present invention to obtain a vehicle occupant protection device which is operated.

[Means for Solving the Problems]

A vehicle occupant protection system according to the present invention is a displacement amount measuring means for predicting a positional transition of a body of an occupant after a predetermined time based on an acceleration signal, and an output from the displacement amount predicting means has a first threshold value. A first comparison circuit that outputs a first determination signal when the speed exceeds, a speed prediction unit that predicts the speed of the upper body of the occupant after a predetermined time based on the acceleration signal, and an output signal from the speed prediction unit. A squaring circuit for squaring to attenuate a noise component and to make a signal component visible; a second comparing circuit for outputting a second judgment signal when an output from the squaring circuit exceeds a second threshold; A gate circuit that ANDs the first and second determination signals from the first and second comparison circuits and outputs a trigger signal when the levels of the first and second determination signals match to operate the main body of the occupant protection device. It is equipped with and.

[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, The first determination signal output when the displacement amount prediction value from the displacement amount prediction means exceeds the first threshold value and the squared value of the speed prediction value from the speed prediction means are evaluated, and the evaluation result is the second threshold value. When a logical product with the second determination signal when the value exceeds the threshold is obtained, a trigger signal is output to operate the occupant protection device main body 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 for integrating (t) has a time constant of T ₂
Has the same function as the first incomplete integrator circuit 2 and incompletely integrates the incomplete integral output v (t) from the first incomplete integrator circuit 2 again incompletely. The first coefficient circuit including the first attenuator for adding the first coefficient to the detection output of the second attenuator having the attenuation factor K of the second attenuator
In the coefficient circuit, the second coefficient circuit 5 adds the second coefficient to the incomplete integration output v (t) of the first incomplete integration circuit 2. 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. Incidentally, the attenuation ratio K is equal to the time t _d required from the supply of the ignition current to the ignition apparatus described later until the expansion of the airbag is completed. 6 is the first
In the addition circuit, the first addition circuit 6 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 to obtain the displacement amount. The predicted displacement amount is output. Reference numeral 7 denotes a first comparison circuit that outputs a first determination signal when the output which is the displacement amount predicted value exceeds a first threshold value. The first determination signal from the first comparison circuit 7 is one of the AND gates 8. Supplied on input. Reference numeral 9 denotes 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 in which the incomplete integral output v (t) of the first incomplete integrator circuit 2 and the output from the third coefficient circuit 9 are added.
In the adder circuit, the second adder circuit 10 outputs the predicted speed value as the displacement speed. 11 evaluates, for example, whether the vehicle is traveling on a bad road or a vehicle has collided depending on the magnitude of the predicted speed value, and in the case of a small predicted value such as traveling on a bad road, square it to a smaller value, Also, in the case of a large predicted value such as a collision, it is a squaring circuit that is an evaluation circuit that squares the value to a larger value, and the squaring circuit 11 squares the moving speed predicted value and outputs it. Reference numeral 12 is a second comparison circuit which outputs a second judgment signal when the evaluation result of the squaring circuit 11 exceeds a second threshold value. The second judgment signal from the second comparison circuit 12 is inputted to the other input of the AND gate 8. Is supplied to. 13 is AND gate 8
A drive circuit that operates based on the output signal of the vehicle, 14 is an ignition device that is the body of the occupant protection device, and this ignition device 14 is a drive circuit
For example, an airbag is operated based on the output of 13.

Next, the operation will be described.

Various accelerations act on the vehicle as the vehicle travels.
If the acceleration sensor 1 detects an acceleration a (t) acting in the front-rear direction of the vehicle as shown in FIG. 2 (A) due to a collision, for example, when the vehicle is traveling at a constant speed v ₀ . , 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 head starts to move and the position immediately before the collision is set as the initial position, the head is displaced forward by x (t) (= ∫v (t) dt) with time. 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 weighted with t _d by the second coefficient circuit 5 and is displaced by v v during the time t _d.
(T) × t _d is obtained. Further, the output a (t) of the acceleration sensor 1 is weighted by 1 / 2t _d ² by the first coefficient circuit 4, and the amount of displacement 1 / 2a (t) × t _d ² during t _d time is obtained. These outputs are added by the first addition circuit 6 to obtain x (t) + v (t) × t _d + 1 / 2a (t) × t _d ² . That is, this is the displacement amount predicted value x (t + t _d ) which is the position of the occupant's head after t _d time from the present time. This displacement amount predicted value is supplied to the first comparison circuit 7, and the position of the occupant's head in FIG.
When the displacement amount predicted value x (t + t _d ) exceeds the first threshold value x of the first comparison circuit 7 at time t ₁ , the first determination signal is supplied to one input of the AND gate 8. To be done. The acceleration signal a (t) is weighted by the third coefficient circuit 9, and the output of the third coefficient circuit 9 and the integrated output of the first integrating circuit 2 are added by the second adding circuit 10 to predict the speed. Output the value. Then, when the speed prediction value from the second addition circuit 10 is evaluated by the squaring circuit 11 and its output exceeds the second threshold value of the second comparison circuit 12, the second determination signal is supplied to the other input of the AND gate 8. To be done. 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 the ignition current to the ignition device 14 to operate the airbag and protect the occupant. That is, when the position for activating the airbag or the like in FIG. 2 (B) is set at a position separated from the initial position by x, the time t _{2 at} which the head position actually reaches x as shown by x (t). It can be seen that the air bag is activated at time t ₁ which is faster than t _{d by} .

In the above embodiment, the first and second incomplete integration circuits are used.
It goes without saying that the time 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 14 to deploy the airbag, but it goes without saying that the seat belt tensioning device may be operated.

Furthermore, although the first and second coefficient circuits are described as attenuators in the above embodiment, it goes without saying that they may be amplifiers 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 comparing circuit that outputs a first determination signal when the threshold value is exceeded, a speed predicting unit that predicts the speed of the occupant's upper body after a predetermined time based on the acceleration signal, and a speed predicting unit from the speed predicting unit. An evaluation circuit that evaluates the output, a second comparison circuit that outputs a second determination signal when the output from the evaluation circuit exceeds a second threshold, and first and second comparison circuits from the first and second comparison circuits. Because the vehicle occupant protection device is provided with a gate circuit that takes the logical product of two determination signals and outputs a trigger signal when the levels of the first and second determination signals match to operate the occupant protection device main body 13. , Acceleration waves at the time of various collisions Without obtained by the experiments reliably predicts the human motion and effect that accurately can activate the occupant protection apparatus.

[Brief description of drawings]

FIG. 1 is a block diagram showing a vehicle occupant protection system 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 ... Square circuit, 12 ... Second comparison circuit,
14 ...... Main body of passenger protection device.

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

Claims (1)

[Claims] 1. A displacement amount predicting means (2, 3, 4, 5,) for predicting a positional transition of an occupant's upper body after a predetermined time based on an acceleration signal.
6) and a first comparison circuit (7) which outputs a first determination signal when the output from the displacement amount prediction means exceeds a first threshold value.
A speed predicting means (2, 9, 10) for predicting the speed of the occupant's upper body after a predetermined time based on the acceleration signal, and the output signal from the speed predicting means is squared to attenuate the noise component. Also, a squaring circuit (11) for eliciting a signal component, a second comparing circuit (12) for outputting a second judgment signal when the output from the squaring circuit exceeds a second threshold value, the first and A gate for taking the logical product of the first and second determination signals from the second comparison circuit and outputting a trigger signal when the levels of the first and second determination signals match to operate the occupant protection device main body (14). A vehicle occupant protection device comprising a circuit (8).