JPH07112802B2 - Driving method for vehicle occupant protection device - Google Patents

Description

Detailed Description of the Invention [Industrial applications]

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

[Prior art]

As a conventional method for driving a vehicle occupant protection device, there are, for example, those disclosed in JP-A-49-55031 and JP-A-2-18134. 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 passed through an integrator and a comparator, and when the integrated output exceeds a predetermined level. The occupant was protected by driving an ignition device such as an airbag system, which is the main body of the occupant protection device, to inflate the airbag and to adjust the seat belt.

[Problems to be Solved by the Invention]

However, in such a conventional method for driving a 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 there is a collision accident that leads to a dangerous state of the occupant due to aging. Acceleration waveforms at the time of a collision are used in order to determine the behavior of the occupant after a vehicle collision without understanding the behavior of the occupant after the vehicle collision and to obtain the optimum operation timing due to the occurrence of the operation delay of the vehicle occupant protection device There was a problem that it was time consuming to collect many of them.
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 it is possible to operate the occupant protection device main body by predicting the movement of the occupant 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 driving method for a vehicle occupant protection device.

[Means for Solving the Problems]

A method for driving an occupant protection device for a vehicle according to the present invention passes an acceleration signal detected by an acceleration sensor through an integrator, and activates the occupant protection device main body when the integrated output exceeds a predetermined threshold value of a comparator. A method for driving a vehicle occupant protection device according to claim 1, wherein the acceleration signal is double-integrated, each integration result in the integration process is weighted, and the result and the double integration result are added. The amount of displacement of the upper body of the occupant after the elapse of time is predicted, and this predicted value is compared with the predetermined threshold value.

[Action]

The method for driving a vehicle occupant protection device according to the present invention predicts the amount of displacement over time until the occupant hits a part of the body on the steering wheel or the like in the event of a vehicle collision by double integrating the acceleration signal. The value is compared with a predetermined threshold value of the comparator, and when the predicted value exceeds the predetermined threshold value, the occupant protection device main body is activated 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 integration circuit 3 for integrating (t) has the same function as the first incomplete integration circuit 2, and the incomplete integration output v (t) from the first incomplete integration circuit 2 is again incomplete. Second to integrate
In the incomplete integration circuit, the time constant of the second incomplete integration circuit 3
T ₂ is the same as the time constant T ₁ of the first incomplete integration circuit 2. Four
Is a first that adds a first coefficient to the detection output of the acceleration sensor 1.
A first coefficient circuit 5 composed of an attenuator is a second coefficient circuit composed of a second attenuator having an attenuation factor of K.
Adds a 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. The damping rate K is the time required from the supply of the ignition current to the ignition device described later to the completion of the inflation of the airbag.
equal to t _d . An adder 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. Reference numeral 7 is a comparison circuit that switches the output level to, for example, a high level when the added output from the addition circuit 6 exceeds a predetermined threshold value, 8 is a drive circuit, and 9 is an ignition device that is the body of the occupant protection device. For example, an airbag is operated based on the output of the drive circuit 8. Next, the operation will be described. Various accelerations act on the vehicle as the vehicle travels.
Now, when the vehicle is traveling at a constant speed v ₀ , the acceleration sensor 1 detects an acceleration a (t) acting in the longitudinal direction of the vehicle as shown in FIG. 2 (A) due to a collision, for example. Then, 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.
As a result, the head starts to move 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) with time. The displacement x (t) is obtained by integrating the output of the first incomplete integration circuit 2 by the second incomplete integration circuit 3,
A predicted displacement of the occupant's head in real time is calculated. Next, the output v (t) of the first incomplete integration 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 is obtained. . Further, the output a (t) of the acceleration sensor 1 is 1/1 by the first coefficient circuit 4.
Weighted by 2t ² _d , 1 / 2a (t) × t ² _d , or t _d
The amount of displacement over time is determined. These outputs are added by the adder circuit 6, and x (t) + v (t) × t _d +
1 / 2a (t) × t ² _d is obtained. In other words, this is the predicted value x (t positions of the occupant's head after the current time t _d time
+ T _d ) is required. This predicted value is supplied to the comparison circuit 7, and the position of the occupant's head is set to the initial position 0 in FIG.
When shifted by x from, that at time t ₁ x (t
+ T _d ) exceeds the threshold value x of the comparison circuit 7 and the ignition device 9
Ignition current is supplied to the air bag 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} . 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 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. Furthermore, although the incomplete integration circuit is used in the above embodiment, it goes without saying that a perfect integration circuit may be used.

【The invention's effect】

As described above, according to the present invention, the acceleration signal whose configuration is detected by the acceleration sensor is determined by the integrator, and whether the integrated output exceeds a predetermined threshold value is determined by the comparator, and the predetermined value is determined. In a driving method for a vehicle occupant protection device, which activates the occupant protection device main body when the threshold value is exceeded, the acceleration signal is double integrated, and the integration result in the integration process is weighted, and the weighting is performed. Predicting the displacement amount of the occupant's state after a predetermined time by adding the result and the result of the double integration, and comparing the predicted value with the predetermined threshold value of the vehicle occupant protection device Since the driving method is used, it is possible to predict the movement of a human after a predetermined time and to operate the occupant protection device body reliably and accurately without obtaining the acceleration waveforms at the time of various collisions by experiments. There is an advantage that it is.

[Brief description of drawings]

FIG. 1 is a block diagram showing a method for driving 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 the detection output of an acceleration sensor at the time of a collision and the displacement amount. FIG. 1 ... Acceleration sensor, 2 ... First incomplete integration circuit, 3 ...
… Second incomplete integration circuit, 7 …… Comparison circuit, 9 …… Main body of passenger protection device.

 ─────────────────────────────────────────────────── ─── 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] Claims: 1. An acceleration signal detected by an acceleration sensor is judged by an integrator, and a comparator judges whether the integrated output exceeds a predetermined threshold value. In the driving method for the vehicle occupant protection device, the acceleration signal is double integrated, and the integration result in the integration process is weighted,
A vehicle characterized by predicting the displacement amount of the occupant's upper body after a predetermined time by adding the weighted result and the double integrated result, and comparing the predicted value with the predetermined threshold value. Driving method for passenger occupant protection device.