JPH10297421A - Occupant protection device for front passenger seat - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prohibit operation of air bag in a front passenger seat when no occupant is seated therein. SOLUTION: A distance to an occupant 20 is measured in a predetermined cycle by means of a distance sensor 22 arranged in front of a front passenger seat. An acceleration sensor 28 detects acceleration in the longitudinal direction of a vehicle. A microcomputer 30 computes a change quantity of the measured distance, and then, computes a correlation value between the vehicle acceleration and the change quantity so as to determine that an occupant is seated when a high correlation is obtained. If no change in the distance continues for a predetermined time, it is determined that no occupant is seated. When it is determined that no occupant is seated, the microcomputer 30 carries out control so as to prohibit inflation of a front passenger seat air bag. In this way, the front passenger seat air bag is not developed when no occupant is seated on the front passenger seat even if a collision is detected.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an occupant protection device such as an air bag device or a seat belt device provided in a vehicle such as an automobile, and more particularly to an operation control of an occupant protection device for a passenger seat.

[0002]

2. Description of the Related Art In the event of an accident such as a vehicle, an occupant protection device for preventing an occupant from hitting a structure inside the vehicle and protecting the occupant has been put to practical use. The occupant protection device
Specifically, there are an air bag device, a seat belt device, and the like. The airbag device deploys an airbag between an occupant and a structure inside the vehicle when the vehicle collides, and serves as a cushion to receive the occupant and prevent the occupant from colliding with the structure. Things. Further, the seat belt device fixes the occupant to the seat and prevents the occupant from colliding with the structure. In particular, in recent years, a seatbelt device with a pretensioner has been put to practical use in which a seatbelt is pulled in a predetermined length at the time of a vehicle collision to more firmly fix an occupant to a seat. In addition, vehicles in which these occupant protection devices are provided not only in the driver's seat but also in the passenger seat are in practical use.

[0003] Japanese Patent Application Laid-Open No. 5-270351 discloses an airbag device. In particular, this device deploys an airbag at an optimum timing according to a seating position of an occupant. The seating position of the occupant is detected by providing a distance sensor on a dashboard in front of the occupant and measuring the distance from the sensor to the occupant.

[0004]

The conventional passenger-seat occupant protection system has a problem even when the occupant is not seated here.
It actually operates at the time of a vehicle collision. This operation is meaningless operation, and when repairing it, it is necessary to replace not only the activated device but also parts such as the dashboard containing the passenger airbag, which increases the repair cost. was there.

[0005] As in the device described in the above-mentioned publication, even if an attempt is made to detect the presence of an occupant based on the distance from the dashboard to the occupant, this is erroneously detected as an occupant, such as when luggage is placed in the passenger seat. there is a possibility.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problem, and has as its object to provide a passenger seat occupant protection device that operates properly depending on the presence or absence of a passenger in a passenger seat.

[0007]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, a passenger seat occupant protection device according to the present invention comprises a protection means for protecting an occupant from a collision with a vehicle internal structure under a predetermined condition; Motion detection means for detecting the movement of the passenger seat occupant in the direction, acceleration detection means for detecting the acceleration of the vehicle, correlation value calculation means for calculating a correlation value between the movement of the passenger seat occupant and the acceleration of the vehicle, An occupant presence / absence determining means for determining the presence / absence of an occupant in the passenger seat based on the detected value of the motion detecting means and the correlation value, and an operation control for controlling the operation of the protection means in the passenger seat based on the determination result of the occupant presence / absence determining means Part and have.

[0008] If acceleration occurs in the vehicle, the occupant moves due to the inertial force generated by the acceleration, and therefore, there is a correlation between the acceleration and the movement of the occupant. Based on this correlation, it can be determined whether or not the occupant is sitting in the passenger seat. If the occupant is not seated, the occupant protection means for the passenger seat is not operated so that the device does not operate when it is not necessary.

The above-mentioned protection means performs a predetermined operation at the time of a vehicle collision, suppresses the movement of the occupant, and prevents the occupant from colliding with the internal structure of the vehicle. Specifically, in the event of a collision, the airbag device is deployed to the front of the occupant to prevent the occupant from colliding with the steering post or dashboard, and the seat belt is retracted by a predetermined length to securely fix the occupant to the seat. The protection means includes a seat belt device with a pretensioner. The present invention can be applied to an occupant protection device using a plurality of these protection means alone or to an occupant protection device using a combination of a plurality of types.

[0010] The movement detecting means includes a movement of a passenger in a passenger seat,
In particular, it detects movement in the vehicle longitudinal direction.
Specifically, it is provided at a predetermined position in the vehicle interior, and has a distance sensor for detecting a distance to a passenger seat occupant, and a movement calculating unit for calculating the movement of the passenger seat occupant based on a change in the distance. be able to. Rather than simply determining the presence or absence of an occupant based on the distance detected by the distance sensor, the occupant can be distinguished from large luggage placed on the passenger seat, for example, by determining the change in distance, that is, the movement of the occupant. Can be.

The correlation value calculating means calculates a correlation value between the vehicle acceleration and the movement of the occupant in the vehicle longitudinal direction. When acceleration occurs in the vehicle, an inertial force acts on an object inside the vehicle. For example, when a brake operation is performed, a negative acceleration (hereinafter, referred to as a deceleration) is generated in the vehicle traveling direction, and thereby an inertial force acts on the occupant in a forward direction. The occupant moves forward due to this inertial force. As described above, since there is a correlation between the vehicle acceleration and the movement of the occupant, the presence or absence of the occupant can be determined by examining the characteristics of the correlation in advance. This determination is made by the occupant presence / absence determination means. As mentioned above, when the occupant is seated,
Since the occupant moves in response to the deceleration caused by the braking, for example, when such a movement having a correlation with the deceleration is detected, it can be determined that the occupant is seated. When the occupant is not seated, the motion detecting means detects the motion of the seat. Since the seat is firmly fixed to the vehicle, no movement due to inertial force occurs. Therefore, there is no correlation with deceleration due to braking,
In such a case, it can be determined that the occupant is not seated.

Particularly, the correlation between the vehicle acceleration and the movement of the occupant is strong when the vehicle is decelerated by a brake operation, and the correlation between the acceleration and the movement of the occupant is obtained when a predetermined amount of brake operation is performed, or It is also preferable to limit the time when a predetermined deceleration occurs.

If the operation of the protection means is controlled based on the above determination, the operation will not be performed when there is no occupant to be protected.

[0014]

Embodiments of the present invention (hereinafter referred to as embodiments) will be described below with reference to the drawings.

FIG. 1 is a schematic configuration diagram of the present embodiment.
Inside a dashboard 14 facing the passenger seat 12 of the vehicle body 10, an airbag body 16 including an airbag and an inflator for deploying the airbag is provided. The deployment of the airbag is controlled by the airbag ECU 18. A passenger seat 12 is provided at the front end of the ceiling of the vehicle body 10.
Sensor 2 that measures the distance to the occupant 20 seated at
2 are installed. In the present embodiment, the distance sensor 22 irradiates the infrared beam 24 and detects the distance based on the time until the reflected light 26 from the measurement target reaches the sensor 22. In the case of such a sensor, its installation position needs to be provided at a position capable of detecting the position of the occupant 20 in the vehicle front-rear direction, and is preferably provided within a plane passing through the center line of the passenger seat. This is because, as will be described later, the movement of the occupant is detected based on the change in the distance measured by the distance sensor 22. Is desirable in terms of accuracy. Therefore, in addition to the above-mentioned ceiling front end, it is also possible to provide it on the dashboard 14. This distance sensor 2
The output of 2 is sent to the airbag ECU 18.

The airbag ECU 18 is provided with an acceleration sensor 28 for detecting the acceleration of the vehicle in the longitudinal direction. Further, the airbag ECU 18 has a microcomputer 30 that operates the inflator according to a program stored in advance based on the output of the distance sensor 22 and the output of the acceleration sensor 28, and deploys the airbag as shown by a dashed line in the figure. Provided.

FIG. 2 is a block diagram showing the configuration of the airbag ECU 18 for controlling the operation of the airbag.
The airbag ECU 18 is provided with the acceleration sensor 28 as described above, and is provided with a microcomputer 30 which performs an operation described below according to a program stored in advance.

The distance sensor 22 measures the distance to the occupant 20 at a predetermined sampling cycle, and sends the result to the motion calculation unit 32 of the microcomputer 30. The movement calculation unit 32 detects the amount of movement during this time, that is, the movement speed of the occupant, from the previous and current measurement results of the distance sensor 22. Therefore, the distance sensor 22 and the motion calculation unit 32
It functions as a movement detecting means for detecting the movement of the front passenger in the front-rear direction.

The output of the motion calculator 32 and the acceleration sensor 28
Is output to the correlation value calculator 34, where a predetermined operation is performed to calculate a correlation value. In the present embodiment, the correlation value is calculated as a product of the occupant's moving speed calculated by the motion calculation unit 32 and the vehicle's deceleration detected by the acceleration sensor 28.

The occupant presence / absence determination unit 36 determines the presence / absence of an occupant based on the calculated correlation value and the calculation result of the motion calculation unit. If there is no occupant, the seat does not move, and the value calculated by the motion calculation unit 32 becomes 0. If this is detected continuously for a predetermined number of times, it is determined that there is no occupant. If the calculated motion value is not 0 and the calculated correlation value is equal to or greater than a predetermined value, it is determined that an occupant is present. Except in the above cases, the determination of the presence or absence of the occupant is suspended, and the determination result up to the previous time is maintained. In the present embodiment, this determination is made at the time of deceleration by a brake in which the correlation between the acceleration of the vehicle and the movement of the occupant is relatively strong, thereby improving the detection accuracy.
In order to determine that it is during deceleration by the brake,
For example, the determination can be made based on the lighting of the brake lamp, or can be determined based on the fact that the master cylinder pressure of the brake has exceeded a predetermined value. It is preferable that the predetermined value of the master cylinder pressure is set to a sufficiently large value that shows a relatively strong correlation between the movement of the occupant and the deceleration by conducting a survey in advance. Alternatively, the above-described determination can be made by directly measuring the deceleration and when the deceleration is equal to or more than a predetermined value. It is desirable that the predetermined value is set to a value indicating a relatively strong correlation between the deceleration and the movement of the occupant, as described above.

The operation control section 38 controls the deployment of the airbag based on the presence or absence of the occupant and the deceleration. That is,
When the deceleration detected by the acceleration sensor 28 is equal to or greater than a predetermined value and the presence or absence of the occupant is determined by the occupant presence / absence determination unit 36, the airbag main unit 16 is instructed to deploy the airbag of the seat. Based on this command, the airbag body 16 operates the inflator to deploy the airbag. Thus, when a large deceleration occurs at the time of a collision or the like, an occupant who is largely moved forward by the inertial force due to the deceleration can be received, and a collision with the windshield or the dashboard can be avoided.

The above-described motion calculation section 32 and correlation value calculation section 3
4. The occupant presence / absence determination unit 36 and the operation control unit 38 are actually the microcomputer 30 itself, and the function of each unit is achieved by the microcomputer 30 operating according to a program stored in advance.

FIG. 3 shows a control flowchart of this embodiment. When the power of the electric components of the vehicle is turned on, an initial check is performed (S100). When the brake is operated by a predetermined amount, the distance S between the sensor 22 and the occupant transmitted from the distance sensor 22 is compared with the previous distance,
It is determined whether or not the distance has changed (S104). If there is no change in the distance, it is determined whether this state of change has continued for a predetermined number of times (S106). If the change has continued for a predetermined number of times, an occupant presence flag indicating that there is an occupant in the passenger seat (P seat) is set. It is cleared (S108). On the other hand, step S10
If it is determined in step 6 that the number has not reached the predetermined number, the occupant presence flag is maintained at the previous state.

If it is determined in step S104 that there is a change in the distance S, the product of the distance change ΔS and the acceleration α detected by the acceleration sensor is calculated as a correlation value X between the two amounts, This is compared with a predetermined threshold value X ₀ (S110). If the correlation value X is a threshold X ₀ or more, it is determined that there are passenger in the passenger seat, to set the occupant state flag (S112). On the other hand, step S11
When 0 the correlation value X is determined to be less than the threshold value X _0, maintains the occupant state flag in the state up to the last time.

Subsequently, the acceleration α is compared with the threshold value α ₀ (S114). If the acceleration α is equal to or more than the threshold value α ₀ , first, a deployment command is issued to the airbag in the driver's seat (D seat) (S114). S116). Next, if the occupant presence flag in the passenger seat is set (S118), a deployment command is issued to the airbag in the passenger seat (S120). In step S114, the detected acceleration alpha is when it is determined to be less than the threshold value alpha _0, the process returns to step S102, the flow described above is performed again. If it is determined in step S118 that there is no occupant in the passenger seat, the process ends without deploying the airbag for the passenger seat.

Although the present embodiment has been described with reference to the airbag device that deploys to the front of the occupant as the occupant protection means, the present invention can also be applied to a so-called side airbag device that deploys to the side of the occupant. Further, the present invention can be similarly applied to a seatbelt device with a pretensioner that retracts the seatbelt by a predetermined amount at the time of a vehicle collision and restrains the movement of the occupant.

Further, in the present embodiment, a distance sensor for measuring a distance based on the arrival time of infrared rays is used as the occupant's movement detecting means, but another known distance sensor may be used. For example, one that measures distance based on the principle of triangulation can be used. Further, instead of the distance sensor, the movement of the occupant may be detected based on an image on the seat.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of an embodiment of the present invention.

FIG. 2 is a configuration block diagram of an airbag ECU that controls the airbag according to the embodiment.

FIG. 3 is a control flowchart of the embodiment.

[Explanation of symbols]

10 vehicle body, 12 passenger seat, 18 airbag ECU,
22 distance sensor, 28 acceleration sensor, 30 microcomputer, 32 motion calculation unit (microcomputer), 34 correlation value calculation unit (microcomputer), 36 occupant presence / absence judgment unit (microcomputer), 38 operation control unit (microcomputer).

Claims (2)

[Claims] 1. Under a predetermined condition, a protection means for protecting an occupant from a collision with a vehicle internal structure, a motion detection means for detecting a movement of an occupant in a front-rear direction of the vehicle, and a front-rear acceleration of the vehicle are detected. Acceleration detecting means, correlation value calculating means for calculating a correlation value between the motion of the passenger seat occupant and acceleration of the vehicle, and determining the presence or absence of a passenger seat occupant based on the detected value of the motion detecting means and the correlation value. An occupant presence / absence determination unit, and an operation control unit that controls the operation of the protection unit in the passenger seat based on the determination result of the occupant presence / absence determination unit,
Passenger seat occupant protection device. 2. The passenger seat occupant protection device according to claim 1, wherein the movement detecting means is provided at a predetermined position in a vehicle compartment,
A passenger seat occupant protection device comprising: a distance sensor that detects a distance to a passenger seat occupant; and a movement calculating unit that calculates a movement of the passenger seat occupant based on a change in the distance.