JP2002067764A - Occupant discrimination system for automobile - Google Patents

Abstract

PROBLEM TO BE SOLVED: To discriminate if output of each sensor cell is affected by stress generated on a form 4 or not as a seat surface 5 is applied. SOLUTION: As a sensor mat 6 is disposed on the form 4, and after the seat surface 5 is applied, a sensor output discrimination process is executed. This sensor output discrimination process is for determining if output of each sensor cell provided on the sensor mat 6 is stable or not, and a specific sensor cell is preliminarily selected as a sensor cell 9a for discrimination, so that an output value of the sensor cell 9a for determination is compared with a discrimination value. When the output value of the discrimination cell 9a is larger than the discrimination value, it is determined that output of each sensor cell is not stable. After running-in work for eliminating stress generated on the form 4, the sensor output discrimination process is executed again. When the output value of the discrimination cell 9a is smaller than the discrimination value, it is determined that output of each sensor cell is stable.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle occupant discriminator for detecting a presence or absence of an occupant on a seat and a child-only seat from a sensor output by incorporating a sensor inside an automobile seat (at a lower portion of a seat). About the system.

[0002]

2. Description of the Related Art Conventionally, as a safety measure to protect an occupant from the impact of a vehicle accident, it is mandatory to wear a seat belt. Therefore, when the seat belt is not worn, a warning light is turned on or a buzzer sounds to warn the occupant that the seat belt is worn. In recent years, the number of vehicles equipped with airbags has been increasing rapidly.For example, vehicles equipped with airbags in the passenger seat have a passenger seat in the event of an accident despite the fact that no occupant is sitting in the passenger seat. Air bag will open.
Therefore, a technique has been put to practical use that prevents the airbag in the passenger seat from opening when the occupant is not sitting in the passenger seat. In order to warn the user of the seat belt and prevent the airbag in the passenger seat from opening, it is necessary to detect in advance whether the occupant is sitting on the seat or not. As a method for detecting the presence or absence of the occupant, an occupant detection system incorporating a pressure-sensitive sensor inside a seat is known.

[0003]

The following dangers have been pointed out because an airbag equipped as a safety device has a large inflation force when opened. For example, in a vehicle in which a passenger seat is equipped with an airbag, when a child is sitting in the passenger seat, the inflation force of the airbag becomes an impact force, which may have an unexpected adverse effect on the child. Therefore, for example, when the occupant in the passenger seat is a child, it is better not to operate the airbag in the passenger seat or to control the inflation force of the airbag so as to reduce the impact. Here, it is conceivable to use the above-described occupant detection system as means for determining whether the passenger in the passenger seat is a child or an adult. That is, if the load detected by the pressure sensor incorporated in the seat is larger than a predetermined value, it can be determined that the vehicle is an adult, and if the load is smaller than the predetermined value, it is determined that the vehicle is a child.

However, when judging whether it is a child or an adult only by the magnitude of the load detected by the pressure-sensitive sensor, there are the following problems. First, even if an occupant is an adult, if the occupant leans his or her back on a seat back (backrest), the load detected by the pressure-sensitive sensor becomes smaller as the seat back is tilted down. I will. Second, when a child-only seat (such as a baby seat, a child seat, or a junior seat) is used in the passenger seat, the weight of the child-specific seat is added to the weight of the child, so that the load increases. Third, when a child-only seat is used, the child-only seat is fixed to the passenger seat with a seat belt.
The load detected by the pressure sensor changes depending on the magnitude of the fastening force of the seat belt. As a result, it is extremely difficult for a conventional occupant detection system to accurately determine whether a child or an adult.

Therefore, the present applicant has developed an occupant discriminating system capable of discriminating a child or an adult accurately with or without a child-specific seat. This occupant discriminating system incorporates a sensor mat in which a plurality of sensor cells are arranged on a plane inside a seat (at a lower portion of a seating surface), and calculates the occupant's weight based on the total load detected from the output values of the individual sensor cells and the load distribution. The determination is performed. For example, regardless of adults and children, the load distribution detected from the output value of each sensor cell is significantly different between a case where a human is directly sitting on the seat and a case where a child-only seat is used.
The presence / absence of a child-specific seat can be detected based on the load distribution. Even when a child-only seat is not used, it is not necessary to judge whether a child or an adult is based solely on the sum of the loads detected by individual sensor cells. It is possible to determine whether the subject is an adult.

In a sheet incorporating a sensor mat, the surface of a sheet foam forming a base (base) is covered with a sheet skin. This sheet skin is stuck with tension to eliminate slack (wrinkles) in appearance. At this time, if the tension of the skin of the sheet is imbalancedly applied to the sheet form, a large stress is generated in a part of the sheet form, and the sensor output becomes unstable due to the influence. As a result, there is a possibility that an erroneous determination may occur in determining the occupant. The present invention has been made based on the above circumstances, and its purpose is to determine whether or not the output of each sensor cell is affected by the stress generated in the sheet form with the attachment of the sheet skin. An object of the present invention is to provide an occupant identification system for an automobile.

[0007]

According to a first aspect of the present invention, there is provided an occupant discriminating system according to the present invention, wherein a sensor mat is provided on an upper surface of a sheet foam forming a base portion of a seat in a manufacturing process of a seat incorporating the sensor mat. After arranging and covering the sensor mat and attaching the sheet skin to the sheet form, a sensor output determination step of determining whether or not the output of each sensor cell is stable is performed. ADVANTAGE OF THE INVENTION According to this invention, when large stress generate | occur | produces in a sheet foam by sticking of a sheet skin, it can judge whether the output of each sensor cell is affected by the stress.

According to a second aspect of the present invention, in the vehicle occupant determination system according to the first aspect, the sensor output determination step selects a specific sensor cell from the sensor mat in advance as a determination cell. It is characterized in that it is determined whether or not the sensor output is stable based on the output value. In this case, it is possible to determine whether or not the output of each sensor cell is stable only by selecting the determination cell on behalf of each sensor cell and monitoring the output value of the determination cell.

According to a third aspect of the present invention, in the vehicle occupant determination system according to the second aspect, when the output value of the determination cell is equal to or greater than a predetermined determination value, it is determined that the sensor output is not stable. After determining, performing a break-in operation for removing a stress generated in the sheet form due to the attachment of the sheet skin, the sensor output determination step is performed again. Thereby, the influence of the stress generated in the sheet form is removed, and a stable sensor output can be obtained. The “break-in work” is, for example, a process of applying an external force or the like to the sheet foam from the surface of the sheet skin to disperse the initial tension of the sheet skin (eliminate the bias of the tension) or correct the position deviation of the sheet skin. It is.

According to a fourth aspect of the present invention, in the vehicle occupant discriminating system according to the third aspect, the sensor mat comprises:
It is characterized in that a determination cell is provided at a portion where a large stress is generated in the sheet form in accordance with the application of the sheet skin in a state where the sheet foam is attached to the inside of the sheet. In this case, since the determination cell is most affected by the stress generated in the sheet form as compared with the other sensor cells, the output value of this determination cell is compared with the determination value to determine the individual sensor cells. It can be effectively determined whether or not the output is stable.

According to a fifth aspect of the present invention, in the vehicle occupant discriminating system according to any one of the second to fourth aspects, the sensor mat includes a dummy sensor in addition to individual sensor cells used for occupant discrimination. This dummy sensor is used as a determination cell. In other words, when a sensor cell that can be used as a determination cell is not provided in the sensor mat at a position that is most affected by the stress generated in the sheet form, a dummy sensor used only in the sensor output determination step may be provided. In addition,
It goes without saying that the dummy sensor can detect the same level of load as the individual sensor cells.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an embodiment of a vehicle occupant discriminating system will be described with reference to the drawings. First, a configuration and a manufacturing process of the sensor-equipped seat 1 used in the occupant identification system for an automobile will be described. The sensor-equipped seat 1 of the present embodiment is a seat cushion for receiving an occupant's buttocks. As shown in FIG. 3, a table 3 supported by a slide rail 2 and a seat form (hereinafter referred to as a form) 4) and a sheet skin 5 covering the surface of the foam 4, and a sensor mat 6 (see FIG. 2) is incorporated between the foam 4 and the sheet skin 5.

Form 4 is the base part (base) of sheet 1
The upper surface is provided with a suspension groove 7 (see FIG. 2) for narrowing the sheet skin 5. Seat skin 5
Is narrowed down into the foam 4 along the suspension groove 7, and the narrowed portion (trench portion) is formed as a design in appearance. Ear hooks 8 (see FIG. 6) for narrowing the sheet skin 5 into the suspension grooves 7 of the foam 4 are provided on the back surface of the sheet skin 5 so as to hang down in a bag shape. In the following description, with respect to the foam 4, a portion surrounded by the two suspension grooves 7 is referred to as a center portion, and a portion outside the suspension grooves 7 is referred to as a side portion. The part surrounded by is referred to as a central part, and the part outside the ear hook part 8 is referred to as a horizontal trim.

As shown in FIG. 2A, the sensor mat 6 has a first sensor portion 6A disposed at the center of the foam 4.
And the second sensor part 6B arranged on the side part of the form 4
, And a plurality of sensor cells 9 are arranged respectively. The sensor cell 9 is, for example, a pressure conversion element whose resistance value changes according to the pressure, and the plurality of sensor cells 9 arranged on the sensor mat 6 can independently detect the pressure. The sensor mat 6 includes a printed circuit board 10
The ECU 11 is connected to the ECU 11 through the ECU 11 and converts a change in pressure detected by each of the sensor cells 9 into an electric signal.
Output to

The ECU 11 is an electronic control unit incorporating a microcomputer, and is incorporated in the center of the rear end of the foam 4 as shown in FIG. 2B, for example. The ECU 11 detects the sum of the loads applied to the seat and the load distribution from the output signals of the individual sensor cells 9 and, based on the detection results, the presence or absence of an occupant, the presence or absence of a child-specific seat, And adults.

A) The presence or absence of an occupant is determined by calculating the sum of the loads detected by the individual sensor cells 9, and if the value is equal to or greater than a predetermined value, it is determined that the occupant is sitting on the seat 1 and is smaller than the predetermined value. For example, it is determined that the occupant is not sitting on the seat 1. b) The presence / absence of the child-only sheet is determined by detecting the load distribution on the sheet from the output signals of the individual sensor cells 9 and determining whether or not the child-specific sheet is used based on the shape pattern estimated from the load distribution. c) For judging a child or an adult, a child or an adult is finally judged by adding a judgment criterion based on a load distribution to a judgment criterion based on a sum of loads.

Next, the manufacturing process of the sensor built-in sheet 1 will be described. FIG. 5 is a flowchart showing the manufacturing process. Step10… Place Form 4 on stand 3. Step 20: The sensor mat 6 is arranged at a predetermined position on the upper surface of the form 4. Here, by temporarily fixing the sensor mat 6 to the form 4, when attaching the next sheet skin 5,
The displacement of the sensor mat 6 can be prevented. Step30: Attach the sheet skin 5.

The work of attaching the sheet skin 5 is generally performed in the following procedure. First step: First, as shown in FIG. 6 (a), the center of the sheet skin 5 is arranged so as to match the center of the foam 4, and the wire 12 passed through the ear hook 8 and the inside of the foam 4 The hook 13 is simultaneously hooked with the C-shaped hog ring 14, and the hog ring 14 is closed and tightened, so that the central portion of the sheet skin 5 covers the central portion of the foam 4.

Second step: Subsequently, the horizontal trim is turned to the side surface of the foam 4 so as to wrap the outside of the side portion of the foam 4, and the hook portion 5a provided at the end of the horizontal trim is mounted on the base 3.
Work to hook on the outer edge part. At this time, in order to prevent the horizontal trim from being loosened (wrinkled), tension is applied to the horizontal trim in an assembled state.
That is, as shown in FIG. 6B, the work of assembling the horizontal trim is performed in a state where the foam 4 is pressed and crushed from above and below, and the hook 5a of the horizontal trim is attached to the outer edge of the base 3 or the like. After hooking, the pressure from the vertical direction is removed. As a result, the side trim of the horizontal trim is applied from the side of the foam 4 in a state where the tension is applied (no slack).
It can be stuck over the side of.

Step 40: A sensor output determination step is performed.
This sensor output determination step is for determining whether or not the output of each sensor cell 9 provided in the sensor mat 6 is stable.
a is selected, and the output value of the determination cell 9a is compared with the determination value (see FIG. 7). The determination cell 9a is disposed at a position (for example, near the four corners and the trench portion of the form 4) where a large stress is generated in the form 4 by the attachment of the sheet skin 5 in a state where the sensor mat 6 is incorporated in the sheet. The sensor cell 9 is used.

If the sensor mat 6 does not have the sensor cell 9 at a position where a large stress occurs in the foam 4, the sensor mat 9 is used only in this sensor output judgment step, separately from the sensor cell 9 used for normal occupant discrimination. A dummy sensor to be used may be provided as the determination cell 9a (see FIG. 2). However, it goes without saying that the dummy sensor can detect the same level of load as the other sensor cells 9.

Next, the determination method will be described. a) The output value of the determination cell 9a is compared with the determination value. If the output value of the determination cell 9a is larger than the determination value, it is determined that the output of each sensor cell 9 is not stable. In this case, as shown in FIG. 1A, a stress is generated in the foam 4 under the tension of the sheet skin 5, and the foam 4 is greatly deformed in a portion where the stress is large. Indicates a value larger than the determination value (see FIG. 7).

Therefore, when the output value of the determination cell 9a is larger than the determination value, a break-in operation for removing the stress generated in the form 4 is performed, and then the sensor output determination step is performed again. In the “break-in work”, for example, an external force or the like is applied to the foam 4 from the surface of the sheet skin 5 to disperse the initial tension of the sheet skin 5 (eliminate the bias of the tension) or to adjust the position of the sheet skin 5. This is the step of correcting. When the stress of the form 4 is removed by this “break-in work”, the deformation of the form 4 is inevitably reduced as shown in FIG. 1B, and accordingly, the output value of the determination cell 9a is also reduced. (See FIG. 7). b) When the output value of the determination cell 9a is smaller than the determination value, it is determined that the output of each sensor cell 9 is stable.

(Effects of the present embodiment) The above-described sensor-equipped sheet 1 is subjected to a sensor output judgment step after the sheet skin 5 is adhered to determine whether or not the output of each sensor cell 9 is stable. Can be determined. Thereby, it is possible to prevent erroneous determination of the occupant determination due to use in a state where the sensor output is unstable. Further, in the sensor output determination step, the output value of the determination cell 9a arranged in the vicinity of the part where the large stress occurs in the form 4 is compared with the determination value. Since this determination cell 9a is most affected by the stress generated in the form 4 as compared with the other sensor cells 9, the individual sensor cells 9 are more likely to be used than when the other sensor cells 9 are used as the determination cells 9a. It is possible to effectively and more reliably determine whether the output is stable.

[Brief description of the drawings]

FIG. 1 is a sectional view of a sheet (a sectional view taken along line AA in FIG. 4).

FIG. 2 is a plan view of a foam having a sensor mat (a).
It is a side view (b).

FIG. 3 is an exploded perspective view of a sheet.

FIG. 4 is a perspective view of a seat.

FIG. 5 is a flowchart showing a sheet manufacturing process.

FIG. 6 is a process diagram for assembling a sheet skin.

FIG. 7 is a graph showing a change in the output value of the determination cell after the sheet skin is attached and after the stress of the foam is removed.

[Explanation of symbols]

 Reference Signs List 1 sensor built-in sheet (sheet) 4 form (sheet form) 5 sheet skin 6 sensor mat 9 sensor cell 9a judgment cell

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Katsushi Mizushima 1-1-1 Showa-cho, Kariya-shi, Aichi F-term in DENSO Corporation (Reference) 3B087 DE08 3D018 QA01 QA05 3D054 AA03 EE10 EE41 FF16

Claims (5)

[Claims] 1. A sensor mat having a plurality of sensor cells arranged on a plane and each of which can independently detect a pressure, wherein the sensor mat is incorporated in a vehicle seat.
An occupant discriminating system for discriminating an occupant on the seat from an output of each of the sensor cells, wherein in the manufacturing process of the seat incorporating the sensor mat, the sensor mat is provided on an upper surface of a sheet form forming a base portion of the seat. And a sensor output judging step of judging whether or not the output of each of the sensor cells is stable after attaching a sheet skin to the sheet form so as to cover the sensor mat. Occupant identification system. 2. The occupant discriminating system for an automobile according to claim 1, wherein said sensor output judging step selects a specific sensor cell from said sensor mat in advance as a judging cell, and sets an output value of said judging cell as an output value. An occupant discriminating system for an automobile, which determines whether or not the sensor output is stable based on the occupant output. 3. An occupant discriminating system for an automobile according to claim 2, wherein when the output value of said discriminating cell is equal to or greater than a preset discriminating value, it is judged that the sensor output is not stable. An occupant discriminating system for an automobile, wherein the sensor output determining step is performed again after performing a break-in operation for removing a stress generated in the seat foam due to the attachment of the seat skin. 4. An occupant discriminating system for an automobile according to claim 3, wherein said sensor mat is installed in said seat, and a large stress is generated in said seat foam as said seat cover is attached. An occupant discriminating system for an automobile, comprising the cell for judgment in a part to be occupied. 5. An occupant discriminating system for an automobile according to claim 2, wherein said sensor mat includes a dummy sensor separately from said individual sensor cells used for occupant discrimination. An occupant discriminating system for an automobile, wherein a sensor is used as the cell for judgment.