JPH0825430B2 - Vehicle occupant protection device - Google Patents

Description

Detailed Description of the Invention

[Industrial applications]

The present invention relates to a vehicle occupant protection device that protects an occupant in the event of a vehicle collision.

[Prior art]

A conventional vehicle occupant protection device is, for example, Japanese Patent Laid-Open No. 49-
There are those disclosed in Japanese Patent Publication No. 55031 and Japanese Patent Laid-Open Publication No. 2-18134. That is, in this publication, a signal waveform of a certain level or more is extracted from the signal from the acceleration sensor, and the extracted signal waveform is passed through an integrator and a comparator.
When the integrated output exceeds a predetermined level, an igniter such as an airbag system, which is the body of the occupant protection device, is driven to inflate the airbag and tighten the seat belt to protect the occupant. .

[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 force signal waveform from the acceleration sensor, and whether or not a collision accident that leads to a dangerous state of the occupant due to a change over time is complicated logic. It is not possible to grasp the behavior of the occupant after the vehicle collision, and it is not necessary to collect many acceleration waveforms at the time of collision in order to obtain the optimal operation timing due to the occurrence of the operation delay of the vehicle occupant protection device. However, there is a problem that it takes 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 operates the occupant protection device main body by predicting the movement of the occupant at the time of a vehicle collision reliably and accurately by performing a few collision experiments as compared with the related art. An object of the present invention is to obtain a vehicle occupant protection device.

[Means for Solving the Problems]

An occupant protection device for a vehicle according to the present invention includes an acceleration sensor that detects an acceleration at the time of a collision of a vehicle, a first incomplete integration circuit that integrates a detection output from the acceleration sensor, and a detection output from the acceleration sensor. A first coefficient circuit for adding one coefficient, a second coefficient circuit for adding a second coefficient to the output from the first incomplete integration circuit, and a second coefficient circuit for further integrating the output from the second incomplete integration circuit An incomplete integration circuit, an addition circuit that adds the respective outputs from the first coefficient circuit, the second coefficient circuit, and the second incomplete integration circuit, and the addition output from this addition circuit exceeds a predetermined threshold value. At this time, the comparison circuit outputs a trigger signal, and the occupant protection device main body operates by receiving the trigger signal from the comparison circuit.

[Action]

The vehicle occupant protection device according to the present invention is designed such that the time until the occupant hits a part of the body on the steering wheel or the like is predicted from the acceleration waveform at the time of a vehicle collision, and the occupant protection device main body is activated 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 upon collision of a vehicle and outputs the state as an analog signal, and 2 has a time constant T ₁ and is output from the acceleration sensor 1. First to integrate analog signals
The incomplete integrator circuit 3 has the same function as the first incomplete integrator circuit 2, and is a second incomplete integrator circuit that again incompletely integrates the incomplete integrator output from the first incomplete integrator circuit 2. 2 The time constant T ₂ of the incomplete integration circuit 3 is the same as the time constant T ₁ of the first incomplete integration circuit 2. 4 is a first coefficient circuit including a first attenuator that adds a first coefficient to the detection output of the acceleration sensor 1,
Reference numeral 5 is a second coefficient circuit including a second attenuator having an attenuation factor of K. The second coefficient circuit 5 adds a second coefficient to the output 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. An adder circuit 6 adds the outputs from the second incomplete integration circuit 3, the first coefficient circuit 4 and the second coefficient circuit 5, and outputs the result. Reference numeral 7 is a comparison circuit for switching the output level to, for example, a high level when the addition output from the addition circuit 6 exceeds a predetermined threshold value, 8 is a drive circuit, and 9 is an ignition device which is the body of the passenger protection device. Based on the output of the circuit 8, for example, an airbag is operated. Next, the operation will be described. Various accelerations act on the vehicle as the vehicle travels. When the vehicle is traveling at a constant speed v ₀ , the acceleration sensor 1 detects the acceleration a (t) acting in the front-rear direction of the vehicle as shown in FIG. Then, the occupant's head is thrown out at a constant velocity v ₀ , while the acceleration a (t) at that time also acts on the occupant. As a result, the head starts moving at a certain relative speed with respect to the vehicle, that is, V (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) as time elapses. 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 integrator circuit 2 is weighted by t _d by the second coefficient circuit 5, and V (t) × t _d , that is, the amount displaced during the time t _{d at} time t. Is required. Further, the output a (t) of the acceleration sensor 1 is weighted by 1 / 2t _d by the first coefficient circuit 4, and 1 / 2a (t) × t
_d, i.e. the amount of displacement between the t _d time at time t is determined. These outputs are added by the adder circuit 6 to obtain x (t) × V (t) × t _d + 1 / 2a (t) × t _d . That is, the predicted value x (t + t _d ) of the position of the occupant's head at time t _d after the present time t is calculated. This predicted value is supplied to the 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 , x (t + t _d ) is the threshold value of the comparison circuit 7. When x is exceeded, an ignition current is supplied to the ignition device 9 to activate the airbag and protect the occupant. That is, when the position for operating 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 it operates at time t ₁ which is faster than t _{d by} . FIG. 3 shows a circuit diagram embodying the vehicle occupant protection device according to the present invention, in which the same parts as those in FIG. 1 are designated by the same reference numerals, and 10 is the output of the first incomplete integration circuit 2. Since the polarity is inverted, the polarity inversion circuit is provided to invert the polarity again and input it to the second incomplete integration circuit 3. In the circuit of FIG. 3, since the threshold value X of the comparison circuit 7 is the divided voltage value of the resistors R1 and R2, if the threshold value X is small,
It is difficult to set during mass production. Therefore, each circuit gain on the input side of the comparison circuit 7 is set to, for example,
By setting the threshold value to 10 times, the threshold value X can also be set to 10 times and the setting becomes easy. In this case, when the multiplication result of the gain and the coefficient of the second coefficient circuit 5 becomes 1, the second coefficient circuit 5 can be regarded as unnecessary as shown in FIG. Therefore, depending on the gain and the coefficients of the first coefficient circuit 4 and the second coefficient circuit 5, the first coefficient circuit 4 can be regarded as unnecessary, or as shown in FIG.
Both coefficient circuits 5 may be required. Further, in the above embodiment, the ignition current is supplied to the ignition device 9 to deploy the airbag, but it goes without saying that the seat belt tensioning device may be activated. Further, although the first and second coefficient circuits have been described as attenuators in the above embodiment, it is needless to say 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 structure thereof includes an acceleration sensor that detects acceleration at the time of a collision of a vehicle, a first incomplete integration circuit that integrates a detection output from the acceleration sensor, and the acceleration sensor. A first coefficient circuit for adding a first coefficient to the detection output of, a second coefficient circuit for adding a second coefficient to the integrated output from the first incomplete integration circuit, and an integration from the first incomplete integration circuit A second incomplete integration circuit for further integrating the output, an addition circuit for adding the respective outputs from the first coefficient circuit, the second coefficient circuit, and the second incomplete integration circuit, and an addition output from the addition circuit Is composed of a comparison circuit that outputs a trigger signal when the vehicle exceeds a predetermined threshold value and the occupant protection device body that operates by receiving the trigger signal from this comparison circuit. Without resulting reliably predicts the human motion after a predetermined time, and the effect is obtained that can be operated accurately 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, FIG. 2 is an output waveform diagram of an acceleration sensor at the time of a collision, and FIG. 3 is a circuit embodying an embodiment of the present invention. It is a figure. 1 ... Acceleration sensor, 2 ... First incomplete integration circuit, 3 ...
2nd incomplete integration circuit, 4 ... 1st coefficient circuit, 5 ... 2nd coefficient circuit, 6 ... addition circuit, 7 ... comparison circuit, 9 ...
Occupant protection device body, 10 ... polarity reversing circuit.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-49-55031 (JP, A) JP-A-3-253441 (JP, A) International publication 90/9298 (WO, A)

Claims (1)

[Claims] 1. An acceleration sensor (1) for detecting acceleration at the time of collision of a vehicle, a first incomplete integration circuit (2) for integrating a detection output from the acceleration sensor, and the first incomplete integration circuit. A second incomplete integration circuit (3) for further integrating the output of the above, a coefficient circuit for weighting the output of the acceleration sensor and / or the output of the first incomplete integration circuit, 2 The addition circuit (6) for adding the output of the incomplete integration circuit and the output of the coefficient circuit to obtain the predicted value x of the head position of the occupant at the time t _d after the present time t, and the output from this addition circuit An occupant protection device for a vehicle, comprising: a comparison circuit (7) which outputs a trigger signal when a predetermined threshold value is exceeded; and an occupant protection device body (9) which operates in response to a trigger signal from the comparison circuit.