JPH04191144A - Occupant crash protection for vehicle - Google Patents

Abstract

PURPOSE:To operate the occupant crash protection main body securely by operating it by receiving a trigger signal output when an integral output as to a collosion detecting wave form from an acceleration sensor exceeds a specific level. CONSTITUTION:An acceleration sensor 1 detects the acceleration signal in a collision, and an integration circuit 2 integrates the acceleration signal as to a collision detecting wave form from the acceleration sensor 1 and outputs the integration constant of the linear scope of the integral wave-form as an integral value. And a comparison circuit 6 decides whether the integral output from the integration circuit 2 is higher than a specific level or not, and when it exceeds the specific level, trigger signal is output. The occupant crash protection main body 8 is operated by receiving the trigger signal from the comparison circuit 6. By such a constitution, the occupant crash protection for vehicle estimates the time up to the time the occupants strike parts of their bodies against a steering or the like accurately from the acceleration wave form at the collision of the vehicle, and operates the occupant crash protection main body 8 securely.

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to a vehicle occupant protection device for protecting an occupant during a vehicle collision.

[Conventional technology]

As a conventional vehicle occupant protection device, for example, Japanese Patent Application Laid-open No. 49
There is one as shown in Japanese Patent No. 55,031. That is, in this publication, a signal waveform of a certain level or more is extracted from a signal from an acceleration sensor, and the extracted f signal waveform is passed through an integrator and a comparator, and when the integrated output exceeds a predetermined level, a signal waveform is output. The ignition device, which is the main body of the occupant protection system, was driven through a drive circuit made up of shots, which inflated the airbag and tightened the seatbelts to protect the occupants.

[Problem to be solved by the invention]

However, in such conventional vehicle occupant protection devices, the output signal waveform from the acceleration sensor is integrated by an integrating circuit, and based on the level of the integrated waveform, it is possible to determine whether or not a collision will result in a serious condition for the occupant. The drive circuit is configured to operate the drive circuit based on the trigger signal determined by the comparison circuit, and if the integration circuit is a complete integration circuit, the output signal of the acceleration sensor will have noise such as offset or drift. In this case, the signal is integrated as is, and an error occurs in the integrated value, resulting in the trigger signal not being generated at the correct time, or
Furthermore, if noises such as offsets and drifts continue to occur for a long time, the integral value will exceed a predetermined level even if no collision occurs, and complex signal processing is required to solve this problem. There was a point. Furthermore, if the integrating circuit is an incomplete integrating circuit and the entire time corresponding to the time constant is used for integration, a negative order lag element will be introduced and linear integration will not be performed. The present invention has been made to solve the above-mentioned problems, and it is an object of the present invention to provide a vehicle occupant protection device that integrates within a range that can be approximated to perfect integration.

[Means to solve the problem]

FIG. 1 shows a diagram corresponding to claims of the present invention. 1 is an acceleration sensor that detects an acceleration signal at the time of a vehicle collision, and 2 is an integration circuit that integrates the acceleration signal related to the collision detection waveform from this acceleration sensor and outputs the integral time constant of the linear range of the integral waveform as an integral value. , 6 is a comparison circuit that determines whether the integrated output from this integration circuit is above a predetermined level, and outputs a trigger signal when it exceeds the predetermined level; 8 is a comparison circuit 6
This is the main body of the occupant protection system that operates in response to a trigger signal from the vehicle. This invention is composed of these components.

[For use]

The vehicle occupant protection device according to the present invention accurately predicts the time until the occupant hits a part of the body against a steering wheel or the like based on the acceleration waveform at the time of a vehicle collision, and reliably activates the occupant protection device itself. It is something.

【Example】

Hereinafter, the present invention will be explained in detail based on the drawings. FIG. 2 is a block diagram showing one embodiment of the present invention.
In the figure, acid parts that are the same or equivalent to those in FIG. 1 are given the same reference numerals and redundant explanation will be omitted. First, to explain the structure, the integration circuit 2 in FIG. 1 consists of a first incomplete integration circuit 2a and a second incomplete integration circuit 2b.The first incomplete integration circuit 2a has a constant T, Acceleration sensor 1 that detects changes in acceleration due to collisions, etc.
It integrates the analog signal output from the . Further, the second incomplete integrating circuit 2b is connected to the first incomplete integrating circuit 2a.
It has the same function as , and incompletely integrates the incompletely integrated output from the first incompletely integrating circuit 2a again. The time constant Tt of the second incomplete integrating circuit 2b is the same as that of the first incomplete integrating circuit 2b.
may be the same or different from the time constant T of a,
The first and second incomplete integration circuits 2a and 2b integrate and output within a range that can be approximated to perfect integration.
The time constants T, , T of the second imperfect integration circuits 'la and 2b are, for example, the maximum target activation time of the occupant protection system body (described later) (from the time a collision occurs until the airbag is fully inflated). time) is set to 10 times T. 3 is a first coefficient circuit consisting of a first attenuator that adds a first coefficient to the detection output of acceleration sensor 1; 4 is a second coefficient circuit whose attenuation rate is K;
A second coefficient circuit consisting of fJ and an attenuator, this second coefficient circuit 4 adds a second coefficient to the integral output of the first incomplete integration circuit 2a. The attenuation rate of the first coefficient circuit 3 is the square of the attenuation rate of the second coefficient circuit 4, which is 172. Note that the above attenuation rate includes the time t required from the time when the ignition current is supplied to the ignition bag W8, which will be described later, until the inflation of the airbag is completed. be equivalent to. 5 is an adder circuit, and this adder circuit 5 is the second adder circuit.
The outputs from the incomplete integration circuit 2b, the first coefficient circuit 3, and the second coefficient circuit 4 are added together and the result is output. The comparison circuit 6 determines whether the addition output from the addition circuit 5 is equal to or higher than a predetermined level, and outputs a trigger signal when the output exceeds the predetermined level. The drive circuit 7 receives the trigger signal from the comparator circuit 6 and outputs a drive signal with a constant pulse width. The ignition device 8, which is the main body of the occupant protection device, receives a drive signal from the drive circuit 7 and operates, for example, an air bag. Next, the operation will be explained. Various accelerations act on the vehicle as the vehicle travels. Now, when a vehicle is traveling at a constant speed, for example, due to a collision, acceleration a(t) occurs in the longitudinal direction of the vehicle, and when that acceleration a(t) is detected by the acceleration sensor, the head of the occupant is While the occupant is thrown at a constant speed, the acceleration a(t) at that time also acts on the occupant. Thereby, the head has a relative velocity with respect to the vehicle, i.e. V(t)
(=fa(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 2a, integrated with a time constant T within a range that can be approximated to perfect integration of the integrated waveform, and output. Furthermore, if the head begins to move and the position immediately before the collision is set as the initial position, x(t)(=f■(t
)dt). This displacement x (t) is the second
The output of the first incomplete integration circuit 2a is integrated by the incomplete integration circuit 2b, and the integration time constant in the linear range of the integrated waveform is output as an integral value to calculate the amount of displacement x of the occupant's head in real time.
(t) is calculated. Next, the first incomplete integration circuit 2a
The output V (t) is weighted by t4 by the second coefficient circuit 4, and (t)Xt6, that is, the amount of displacement within time t4 is determined. Furthermore, the output a (t) of the acceleration sensor 1 is converted to 1/2t2d by the first coefficient circuit 3.
1/2a(t)
V(t) , ) are supplied to the comparator circuit 6, and in FIG.
When (t+t,) exceeds the threshold value X of the comparison circuit 6, the drive circuit 7 supplies a drive signal and ignition current to the ignition device of the occupant protection device main body 8 to activate an airbag or the like to protect the occupant. FIG. 4 shows a circuit diagram embodying the vehicle occupant protection device according to the present invention, in which the same parts as in FIG. Since the polarity of the input signal is inverted, this polarity inversion circuit is provided to invert the polarity of the input signal again and input it to the second incomplete integration circuit 2b. In this FIG. 4, the second coefficient circuit 4 has a 1
The settings are such that the output is multiplied by .

【Effect of the invention】

As described above, according to the present invention, the configuration includes an acceleration sensor that detects an acceleration signal at the time of a vehicle collision;
An integrator circuit that integrates and outputs an acceleration signal related to a collision detection waveform from this acceleration sensor within a range that can be approximated to perfect integration; The vehicle occupant protection device is equipped with a comparison circuit that outputs a trigger signal when the vehicle exceeds the threshold, and a body of the device that operates in response to the trigger signal from the comparison circuit, so that the acceleration waveform during a vehicle collision is linear. Since it is integrated, the acceleration waveform is integrated with high precision, and the time until a part of the passenger's body hits the steering wheel etc. can be accurately predicted, and the output error from the acceleration sensor can be calculated without complicated processing. This has the effect of reducing the negative effects of the vehicle occupant protection system and ensuring the operation of the occupant protection device body.

[Brief explanation of drawings]

FIG. 1 is a claim correspondence diagram showing a vehicle occupant protection device according to the present invention, FIG. 2 is a block diagram showing an embodiment of the vehicle occupant protection device according to the present invention, and FIG. 3 is a diagram showing an acceleration sensor at the time of a collision. Integral waveform diagram when integrating the output waveform, 4th
- The figure is a circuit diagram embodying an embodiment of the present invention. DESCRIPTION OF SYMBOLS 1... Acceleration sensor, 2... Integrating circuit, 6... Comparison circuit, 7... Drive circuit, 8... Occupant protection device main body. In addition, in the figures, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Claims] Acceleration sensor (
1), an integrating circuit (2) that integrates and outputs an acceleration signal related to a collision detection waveform from this acceleration sensor within a range that can be approximated to perfect integration, and whether the integrated output from this integrating circuit is equal to or higher than a predetermined level. A vehicle occupant protection system comprising: a comparison circuit (6) that determines whether or not the current level has reached a predetermined level and outputs a trigger signal when the level exceeds a predetermined level; and an occupant protection device main body (8) that operates upon receiving the trigger signal from the comparison circuit. Device.