JPH07251699A - Control device for occupant restraining device - Google Patents

Abstract

PURPOSE:To reduce a man-hour for adjusting a device by providing a limit means for limiting an output of a vehicle deceleration detecting means to within preset upper/lower limits, integrating deceleration, and providing a means for determining operation of an occupant restraining device when this integrated value exceeds a prescribed threshold value. CONSTITUTION:In a deceleration sensor 1, deceleration of a vehicle is detected and output to a control circuit 2, and in an AD converter 2 of the control circuit 2, a deceleration signal input from the deceleration sensor 1 is digitally converted and output to a low-pass filter 1b and to a limiter 2c. In the limiter 2c, in order to limit the input deceleration to prescribed upper/lower limits or less, an output deviation due to an offset and drift of the deceleration sensor 1 is extracted, to change, in accordance with this output deviation, upper/lower limit values of the limiter 2c, to integrate the deceleration by an integrater 2d compared with a threshold value Vref and to output an operation command of an air bag to a drive circuit 3 when the deceleration exceeds this threshold value. Accordingly, the deceleration is accurately detected, and an adjusting man-hour can be reduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an occupant restraint system control device for restraining and protecting an occupant in the event of a collision.

[0002]

2. Description of the Related Art A control device for controlling the operation of an occupant restraint device such as an air bag or a seat belt is known (for example, see Japanese Patent Laid-Open No. 4-503339). In this type of control device, the deceleration of the vehicle detected by the deceleration sensor is integrated, and the occupant restraint device is operated when the integrated value reaches a preset threshold value.

By the way, a control device for an occupant restraint system is usually composed mainly of a microcomputer, and the deceleration detected by the deceleration sensor is converted into a digital value by an AD converter and input to the microcomputer. The computer calculates the deceleration integral and compares the integral value with the threshold value. Usually, a microcomputer limits the input deceleration to limit the input of noise or the like that exceeds a predetermined upper limit value and lower limit value.

However, there are output deviations due to offsets and drifts in the output of the deceleration sensor, and the values also change from moment to moment due to product variations and environmental conditions, and the upper and lower limit values in the limiter processing are kept constant. The result after performing the integration processing changes and the desired control performance cannot be obtained.

Therefore, in order to solve such a problem, in the conventional occupant restraint system control device, an auxiliary algorithm for processing the output deviation of the deceleration sensor is added to obtain a desired performance. Is complicated and requires a lot of adjustment man-hours.

An object of the present invention is to reduce the adjustment man-hours of a control device for an occupant restraint system.

[0007]

The inventions of claims 1 and 2 will be described with reference to FIG. 1 showing an embodiment.
According to the invention of claim 1, the deceleration detecting means 1 for detecting the deceleration of the vehicle, the limit means 2c for limiting the output of the deceleration detecting means 1 to within the preset upper and lower limit values, and the limit means 2c. Of the occupant restraint system including an integrating means 2d for integrating the deceleration output from the occupant restraint system and an actuation determining means 2e for determining the actuation of the occupant restraint system when the integrated value of the integrating means 2d exceeds a predetermined threshold value. Applies to control equipment.
Then, the output deviation detecting means 2b for detecting the output deviation of the deceleration detecting means 1, and the upper and lower limit value changing means for changing the upper and lower limit values of the limit means 2c according to the output deviation detected by the output deviation detecting means 2b. 2c, thereby achieving the above-mentioned object. The output deviation detecting means 2b of the control device for an occupant restraint system according to claim 2 detects a low frequency component of a predetermined frequency or less from the deceleration detected by the deceleration detecting means 1 as an output deviation of the deceleration detecting means 1. It was done like this. Further, the invention of claim 3 will be described in association with FIG. 6 showing a modified example of the embodiment. A predetermined deceleration is applied to the output deviation detecting means of the control device of the occupant restraint system of claim 3. Deceleration switch means 6a
And a storage means 2f for storing the output of the deceleration detection means 1 when the deceleration switch means 6a is not operating, and the storage means 2f when the deceleration switch means 6a is operated by the upper and lower limit value changing means 2g. The upper and lower limit values of the limit means 2g are changed according to the value stored in the.

[0008]

Operation is performed when a low frequency component having a predetermined frequency or lower is detected as an output deviation of the deceleration detecting means 1 from the deceleration detected by the deceleration detecting means 1, or when a predetermined deceleration is applied. The output of the deceleration detecting means 1 when the deceleration switch means 6a is not operating is detected as an output deviation, and the upper and lower limit values of the limit means are changed according to the detected output deviation. The deceleration in the inside is accurately detected, the adjustment of the control device is simplified, and the adjustment man-hour can be reduced.

Incidentally, in the section of means and action for solving the above-mentioned problems for explaining the constitution of the present invention, the drawings of the embodiments are used in order to make the present invention easy to understand. It is not limited to.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the control device for an occupant restraint system of the present invention is applied to an air bag control device for inflating and deploying at the time of a collision to protect an occupant will be described. FIG. 1 is a functional block diagram showing the configuration of one embodiment. The deceleration sensor 1 is provided in, for example, a floor tunnel portion in the vehicle compartment, detects deceleration of the vehicle, and outputs the deceleration to the control circuit 2. The control circuit 2 includes a microcomputer and peripheral components such as an AD converter, and executes a control program described later to control the operation of the occupant restraint system. The drive circuit 3 energizes the squib 5 of the air bag module from the power source 4 according to the operation command of the control circuit 2 to activate the inflator of the air bag module to inflate and deploy the air bag module. The safing sensor 6 is a mechanical sensor whose contacts are closed when a predetermined deceleration is applied, and operates at a slightly lower deceleration than an electrical sensor composed of the deceleration sensor 1 and the control circuit 2 operates. Is set as follows.

In this embodiment, an air bag control device will be described as an example, but the present invention can be applied to a control device for another occupant restraint device such as a seat belt.

The control circuit 2 has the following functions by the software of the microcomputer. The AD converter 2a converts the deceleration signal input from the deceleration sensor 1 into a digital value, and the low pass filter 2b
And output to the limiter 2c. Low pass filter 2b
Then, a low frequency component of, for example, several Hz or less is extracted from the input deceleration and output to the limiter 2c. On the other hand, the limiter 2c limits the input deceleration to a predetermined upper or lower limit value or less. As the upper and lower limit values, an initial value when the low frequency component of the deceleration from the low pass filter 2b is 0 is set in advance, and a value obtained by adding the output from the low pass filter 2b to the initial value is set. That is, low pass filter 2
The output deviation amount due to the offset or drift of the deceleration sensor 1 is extracted by b, and the upper and lower limit values of the limiter 2c are changed according to the extracted output deviation. Next, the integrator 2d
The deceleration is integrated with, and the integrated value is used in comparator 2.
It is compared with the threshold value Vref at e. When the integrated value of deceleration exceeds the threshold value Vref, an air bag operation command is output to the drive circuit 3.

2 to 4 are diagrams for explaining a method of setting the upper and lower limit values of the limiter 2c. Now, the standard output characteristics of the deceleration sensor 1 are 0.5V / -50G to 2.5V / 0G
.About.4.5 V / + 50 G, and an initial value of ± 50 G is set as the upper and lower limit values of the limiter 2c for the deceleration sensor 1 having such standard output characteristics. When there is no output deviation due to offset or drift in the output of the deceleration sensor 1, the upper and lower limits of the limiter 2c are set to the initial value ± 50G, and the detected deceleration in this range is set by the limiter 2c as shown in FIG. Not limited. However, if there is an output deviation due to offset or drift in the output of the deceleration sensor 1 and the true zero point deviates from the initially set zero point,
As shown in FIG. 3, the output of the deceleration sensor 1 is actually +
Although it is only 50 G, it exceeds 4.5 V, and the limit is limited by the limiter 2c.

Therefore, when the true zero point of the deceleration sensor 1 deviates from the initially set zero point of 2.5 V, the deviated portion is offset or drifted as shown in FIG. It is regarded as the output deviation, and the deviation is added to the initially set upper and lower limit initial values to increase or decrease the upper and lower limits by the output deviation. By doing so, the output deviation due to the offset or drift of the deceleration sensor 1 is reduced, and the deceleration within the predetermined range can be accurately detected.

The AD converter 2a is selected so that its allowable input range is larger than the output range of the deceleration sensor 1. For example, when the standard output characteristic of the deceleration sensor 1 is 0.5V / -50G to 4.5V / + 50G, the allowable input range is 0 to 4.
Select 9V AD converter.

FIG. 5 is a flow chart showing a control program of the microcomputer. The operation of the embodiment will be described with reference to this flowchart. The deceleration is input from the deceleration sensor 1 in step S1, and the deceleration input in the subsequent step S2 is AD-converted. Step S3
Then, the input deceleration is filtered to extract low-frequency components of, for example, several Hz or less, and the process proceeds to step S4.
In step S4, the initial values of the upper and lower limit values initially set according to the low frequency component of the deceleration are changed, and if the input deceleration exceeds the changed upper and lower limit values, it is limited to the upper and lower limit values or less. . In step S5, the deceleration that has undergone limit processing to remove unnecessary components such as noise is integrated, and the flow proceeds to step S6 to determine whether the integrated value exceeds the threshold value Vref. The integrated value of deceleration is the threshold value Vref
If it exceeds, the process proceeds to step S7, an air bag operation command is output to the drive circuit 3, and the integrated value becomes the threshold value Vre.
If it is less than or equal to f, the process returns to step S1 and the above process is repeated. When an air bag operation command is output from the control circuit 2 to the drive circuit 3, the drive circuit 3 causes the power supply 4 to move to the squib 5.
Energize to activate the inflator and inflate and deploy the airbag.

As described above, the low frequency component of, for example, several Hz or less is extracted from the detected value of the deceleration, and the upper and lower limit values of the deceleration initially set are changed according to the low frequency component. The deceleration within the range is accurately detected, the adjustment of the control device is simplified, and the adjustment man-hour can be reduced.

In the above-described embodiment, the detected deceleration is low-pass filtered to extract a low frequency component of several Hz or less, that is, an output deviation due to the offset or drift of the deceleration sensor. It is also possible to use a mechanical sensor that is activated when is applied.
That is, the safing sensor described above is separately provided with a contact that is closed by several G, and the output value of the deceleration sensor when this contact is in the open state is used as the output deviation due to the offset or drift.

FIG. 6 is a functional block diagram showing the structure of a modification of the above embodiment. It should be noted that the same reference numerals are given to the same devices as those in FIG. 1 showing the configuration of the embodiment, and the differences will be mainly described. The safing sensor 6a is
For example, it is a mechanical sensor whose contacts close when a deceleration of several G is applied. The memory 2f stores the input deceleration when the contact of the safing sensor 6a is open and not operating, as the output deviation of the deceleration sensor 1. The limiter 2g changes the upper and lower limit values according to the output deviation stored in the memory 2f from the input deceleration when the contact of the safing sensor 6a is closed, and limits the input deceleration to the upper or lower limit value after the change. To do.

FIG. 7 is a flow chart showing a control program of a modified example of the above embodiment. It should be noted that the same step numbers are given to the steps that perform the same processing as in the flowchart shown in FIG. 5, and the differences will be mainly described. In step S3a after AD conversion of the input deceleration, it is determined whether or not the contact of the safing sensor 6a is closed, and if closed, the process proceeds to step S4a, and if not, the process proceeds to step S3b. When the contact point of the safing sensor 6a is not closed, the input deceleration is regarded as the output deviation of the deceleration sensor 1 and stored in the memory 2f in step S3b. On the other hand, when the contact of the safing sensor 6a is closed, the memory 2 is read at step S4a.
The initial value of the upper and lower limit values initially set according to the output deviation of the deceleration sensor 1 stored in f is changed, and if the input deceleration exceeds the changed upper and lower limit values, the upper and lower limit values Limited to:

As described above, the safing sensor 6a which operates at several G is provided, the input deceleration when the sensor 6a is not operating is stored as the output deviation of the deceleration sensor 1, and is output when the sensor 6a operates. Since the upper and lower limits are changed according to the deviation, the deceleration within the predetermined range can be accurately detected, the adjustment of the control device can be simplified, and the adjustment man-hour can be reduced.

In the structure of the above embodiment, the deceleration sensor 1 serves as the deceleration detecting means and the limiters 2c and 2g.
Is a limiting means, an integrator 2d is an integrating means, a comparator 2e is an operation determining means, and a low-pass filter 2b.
Represents the upper and lower limit value changing means, the safing sensor 6a constitutes the deceleration switch means, and the memory 2f constitutes the storage means.

[0023]

As described above, according to the present invention, a low frequency component below a predetermined frequency is detected as an output deviation of the deceleration detecting means from the deceleration detected by the deceleration detecting means, or , The output of the deceleration detecting means when the deceleration switch means that operates when a predetermined deceleration is applied is not operating is detected as an output deviation, and the upper and lower limit values of the limit means are changed according to the detected output deviation. Therefore, the deceleration within the predetermined range is accurately detected,
The adjustment of the control device is simplified, and the adjustment man-hour can be reduced.

[Brief description of drawings]

FIG. 1 is a functional block diagram showing the configuration of an embodiment.

FIG. 2 is a diagram illustrating a method of setting upper and lower limit values of a limiter.

FIG. 3 is a diagram illustrating a method of setting upper and lower limit values of a limiter.

FIG. 4 is a diagram illustrating a method of setting upper and lower limit values of a limiter.

FIG. 5 is a flowchart showing a control program of a microcomputer.

FIG. 6 is a functional block diagram showing a configuration of a modified example of the embodiment.

FIG. 7 is a flowchart showing a control program of a modified example of the embodiment.

[Explanation of symbols]

 1 deceleration sensor 2 control circuit 2a AD converter 2b low pass filter 2c limiter 2d integrator 2e comparator 3 drive circuit 4 power supply 5 squib 6 safing sensor

Claims (3)

[Claims] 1. A deceleration detecting means for detecting a deceleration of a vehicle, a limit means for limiting an output of the deceleration detecting means within a preset upper and lower limit value, and a deceleration output from the limiting means. In the control device for the occupant restraint system, the deceleration detecting means comprises: an integrator that integrates the occupant restraint device; And an upper and lower limit value changing means for changing the upper and lower limit values of the limit means according to the output deviation detected by the output deviation detecting means. Control device for restraint system. 2. The control device for an occupant restraint system according to claim 1, wherein the output deviation detecting means includes a low frequency component having a predetermined frequency or less from the deceleration detected by the deceleration detecting means. A control device for an occupant restraint device, which is detected as an output deviation of a detection means. 3. The occupant restraint system control device according to claim 1, wherein the output deviation detection means is a deceleration switch means that operates when a predetermined deceleration is applied, and a non-deceleration switch means of the deceleration switch means. A storage unit that stores the output of the deceleration detection unit during operation, wherein the upper limit value changing unit is the limit unit according to a value stored in the storage unit when the deceleration switch unit operates. A control device for an occupant restraint system, characterized in that the upper and lower limit values of the above are changed.