JP2002022578A - Occupant discrimination system for automobile - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent an erroneous judgement due to positional displacement of a sensor mat 6 for an occupant discrimination system made by installing the sensor mat 6 under the seating surface of a seat. SOLUTION: The seat with a built-in sensor is made by incorpolating the sensor mat 6 under the seating surface of the trim and incorporating an ECU 11 in a rear end part of the seat. The ECU 11 detects load distribution on the seat by receiving signals inputted from sensor cells 9 disposed on the sensor mat 6. If the sensor mat 6 incorporated in the seat is not disposed in the normal position, the load distribution detected when actually used is deviated from the normal load distribution and therefore a correction process is performed to correct the deviation of the load distribution. Specifically, a center part of the seating surface of the trim is pressed in its specified area, and the displacement of the sensor mat 6 is estimated from the output of previously selected sensor cells 9 to correct the deviation of the load distribution according to the displacement.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle for detecting a load distribution on a seat from a sensor output by incorporating a sensor inside a vehicle seat, and determining whether a passenger is a child or an adult by taking the load distribution into consideration. The occupant discrimination 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. 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 in the passenger seat. In order to warn the user of the seat belt or to prevent the airbag in the passenger seat from opening, it is necessary to detect in advance that an occupant is present (seated) on the seat or not. There is a need. 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]

However, the following dangers have been pointed out because airbags equipped as safety devices have a large inflation force when opened. For example, in a vehicle equipped with an airbag in the front passenger seat, when a child is in the front passenger seat, the inflation force of the airbag becomes an impact force, which may have an unexpected adverse effect on the occupant (child). is there. Therefore, for example, if the passenger in the passenger seat is a child,
It is better not to activate the passenger airbag. 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 (a baby seat, a child seat, a junior seat, or the like) is used in the passenger seat, the weight of the child-only seat is added to the weight of the child, and the load increases. Third, when a child-specific seat is used, the child-specific seat is fixed to the front passenger seat with a seatbelt, so that the load detected by the pressure-sensitive sensor changes depending on the magnitude of the fastening force of the seatbelt. 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 that can discriminate between a child and an adult irrespective of the presence or absence of a child-only seat. This occupant discriminating system incorporates a sensor mat, in which a plurality of sensor cells are arranged on a plane, into a lower portion of a seat, detects a load distribution on the seat from the output of each sensor cell, and estimates a shape estimated from the load distribution. The presence / absence of a child-only sheet is detected by a pattern. 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.

However, in the above occupant discriminating system, since the sensor mat is not mechanically positioned with respect to the seat, there is a possibility that the position of the sensor mat shifts when assembling a seat cover that covers the surface of the seat. There is. If the sensor mat is actually used in this state (the state where the sensor mat is displaced), the load distribution obtained from the output of each sensor cell will be deviated. Get higher. The present invention has been made based on the above circumstances, and an object of the present invention is to prevent an erroneous determination due to a misalignment of a sensor mat in an occupant discriminating system incorporating a sensor mat below a seat surface. .

[0007]

According to a first aspect of the present invention, an occupant discriminating system according to the present invention includes:
After the sensor mat is assembled and the seat cover that covers the seat surface of the seat is assembled, the method includes a correction step of correcting a shift in the load distribution due to a positional shift of the sensor mat. As a result, even if the sensor mat is displaced from the normal position with respect to the seat, the misalignment of the sensor mat is prevented by correcting the displacement of the load distribution according to the displacement amount. it can.

According to a second aspect of the present invention, in the vehicle occupant discriminating system according to the first aspect of the present invention, in the correcting step, the pressure is applied to the seat surface of the seat with a fixed area so that the sensor cell from the sensor cell selected in advance. A position shift amount of the sensor mat is estimated based on the output signal, and a load distribution shift is corrected according to the position shift amount. In this case, the displacement amount of the sensor mat can be estimated from a comparison between the magnitude of the load detected by the sensor cell selected in advance and the pressing area pressed on the sheet.

According to a third aspect of the present invention, in the vehicle occupant discriminating system according to the second aspect, in the correction step, at least two of the sensor mats arranged in a specific direction on the sensor mat are arranged.
The number of sensor cells is selected in advance, the amount of displacement of the sensor mat is estimated based on a signal output from the selected sensor cell, and the displacement of the load distribution is corrected according to the amount of displacement. In this case, since at least two sensor cells selected in advance are arranged in a specific direction on the sensor mat, by comparing the outputs of the at least two sensor cells, the amount of displacement of the sensor mat in the specific direction can be determined. It can be easily estimated.

According to a fourth aspect of the present invention, in the vehicle occupant discriminating system according to the third aspect, the at least two sensor cells arranged in a specific direction on the sensor mat are the front-rear direction or the left-right direction of the sensor mat. It is characterized in that there are at least two sensor cells at target positions in the direction. In this case, since at least two sensor cells selected in advance are arranged at target positions in the front-rear direction or the left-right direction of the sensor mat, the outputs of the at least two sensor cells are compared to determine the front-rear direction or the left-right direction. It is possible to easily estimate the displacement amount of the sensor mat in the direction.

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, in the correcting step, when the sensor mat is in a normal position, a pressure is applied to the seat surface of the seat. A sensor cell arranged in a position deviating from a predetermined area is selected in advance, a displacement amount of the sensor mat is estimated based on a signal output from the selected sensor cell, and a load distribution is performed in accordance with the displacement amount. Is corrected. In this case, since the pressure is applied to a fixed area where the load is not directly applied directly above the selected sensor cell, the amount of displacement of the sensor mat can be estimated based on the magnitude of the load detected by the selected sensor cell. .

According to a sixth aspect of the present invention, in the vehicle occupant discriminating system according to any one of the second to fourth aspects, in the correcting step, when the sensor mat is at a normal position, pressure is applied to the seat surface of the seat. The sensor cells arranged in a certain area are selected in advance, and the position shift amount of the sensor mat is estimated based on the signal output from the selected sensor cell, and the shift of the load distribution is calculated according to the position shift amount. It is characterized by correction. In this case, since pressure is applied in a certain area where a load is directly applied directly above the selected sensor cell,
The amount of displacement of the sensor mat can be estimated based on the magnitude of the load detected by the selected sensor cell.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an embodiment of a vehicle occupant discriminating system will be described with reference to the drawings. 1 and 2 are explanatory diagrams of a process for correcting a deviation of a load distribution. First,
The configuration and manufacturing process of the sensor-equipped seat 1 used in the occupant identification system for a vehicle will be described. The sensor-equipped seat 1 of this embodiment is a seat cushion (see FIG. 3) for receiving a passenger's buttocks, and as shown in FIG. It comprises a urethane foam (hereinafter abbreviated as a form 4) and a sheet skin (hereinafter referred to as a trim 5) that covers the surface of the foam 4, and a sensor mat 6 is incorporated between the foam 4 and the trim 5.

As shown in FIG. 5, the foam 4 forms the entire shape of the sheet 1, and has a suspension groove 7 for narrowing (suspending) the trim 5 on its upper surface. The trim 5 is narrowed down to the inside of the foam 4 along the hanging groove 7, and the narrowed portion (trench portion) is formed as a design in appearance. Ear hooks 8 on the back of the trim 5 for narrowing the trim 5 into the suspension grooves 7 of the foam 4 (see FIG. 7)
Is provided hanging down like a bag. In addition, regarding the form 4, the portion surrounded by the two suspension grooves 7 is a central portion,
A portion outside the hanging groove 7 is called a side portion, and a portion surrounded by the ear hook portion 8 is called a center portion, and a portion outside the ear hook portion 8 is called a horizontal trim portion.

As shown in FIG. 5A, the sensor mat 6 has a first sensor section 6A arranged 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 on the sheet surface, respectively.
Is arranged. 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.

In the first sensor section 6A, a plurality of sensor cells 9 are arranged at regular intervals in the front-rear direction and the left-right direction on a rectangular sheet surface. In the second sensor section 6B, a plurality of sensor cells 9 are arranged at equal intervals on a sheet surface that is elongated in the front-rear direction along the side portion of the foam 4. The first sensor unit 6A and the second sensor unit 6B are integrally provided with their sheet surfaces connected to each other. The sensor mat 6 is connected to the ECU via the printed circuit board 10.
The sensor 11 is connected to the ECU 11 and converts a change in pressure detected by each sensor cell 9 into an electric signal and outputs the electric signal to the ECU 11.

The ECU 11 is an electronic control unit containing a microcomputer, and is incorporated in the rear end of the foam 4 as shown in FIG. 5B, for example. This E
The CU 11 detects the sum of the loads applied on the sheet and the load distribution from the output signals of the individual sensor cells 9,
Based on the detection result, the presence or absence of an occupant described below,
The presence / absence of a child seat and the distinction between children and adults are made.

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. 6 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. Step30… Assemble trim 5 The work of assembling the trim 5 is generally performed according to the following procedure. First step: First, as shown in FIG. 7, the center of the trim 5 was 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 were provided. The wire 13 and the C-shaped hog ring 14 are simultaneously hooked, and the hog ring 14 is closed and tightened, so that the center of the trim 5 covers the center 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 5 a 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, the assembling work of the horizontal trim is performed in a state in which the foam 4 is pressed from above and below and crushed as shown in FIG. 8, and after the hook 5a of the horizontal trim is hooked on the outer edge of the base 3 or the like. The pressurization from the vertical direction is removed. As a result, the horizontal trim is attached from the side portion of the foam 4 to the side surface of the foam 4 in a state where tension is applied (in a state where there is no slack).

Step 40: A correction step is performed. In this correction step, the load distribution detected by the ECU 11 during actual use may deviate from the normal load distribution unless the sensor mat 6 incorporated in the lower part of the seat surface of the seat 1 is placed at a normal position. , To correct the deviation of the load distribution. Hereinafter, the procedure of the correction process will be described with reference to FIGS. First, at least two sensor cells 9 are selected in advance. In this case, it is desirable to select at least two sensor cells 9 arranged at target positions at a certain interval in a specific direction (for example, the front-back direction, the left-right direction) of the sensor mat 6.

Subsequently, as shown in FIG. 1, a load is applied to the center of the seating surface of the trim 5 using an indenter 15. At this time,
Pressure is applied to an area where a load is not directly applied directly above at least two selected sensor cells 9. Alternatively, pressure is applied to an area where a load is directly applied directly above at least two selected sensor cells 9. Subsequently, the outputs of the at least two sensor cells 9 selected in advance and the sensor cells 9 in the vicinity thereof are compared with the outputs (FIG. 1) when the sensor mat 6 is arranged at a normal position (FIG. 1). Is estimated. For example, in the case shown in FIG. 2, it can be estimated that the sensor mat 6 is displaced rightward in the figure by one cell as compared with the case where the sensor mat 6 is arranged at a normal position. Finally, the ECU 11 corrects the deviation of the load distribution obtained from the output of each sensor cell 9 according to the estimated deviation amount of the sensor mat 6.

(Effects of the present embodiment) In the vehicle occupant discriminating system of the present embodiment, after assembling the seat 1, the amount of positional shift of the sensor mat 6 incorporated in the seat 1 is estimated, and the amount of shift is estimated. A correction step is provided for correcting a deviation of the load distribution detected from the output of each sensor cell 9 accordingly. Accordingly, even if the sensor mat 6 is assembled to the sheet 1 with a deviation from the normal position, the deviation of the load distribution is corrected in accordance with the deviation amount. Erroneous determination can be prevented.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of a process of correcting a deviation of a load distribution.

FIG. 2 is an explanatory diagram of a process of correcting a deviation of a load distribution.

FIG. 3 is a perspective view (a) and a sectional view (b) of a seat cushion.

FIG. 4 is an exploded perspective view of the sensor mat.

FIG. 5 is a plan view of a foam having a sensor mat (a).
And a side sectional view (b).

FIG. 6 is a flowchart showing a manufacturing process of the sensor-containing sheet.

FIG. 7 is a sectional view showing a first step for assembling the trim.

FIG. 8 is a cross-sectional view showing a second step for assembling the trim.

[Explanation of symbols]

 1 sheet 5 trim (seat skin) 6 sensor mat 9 sensor cell

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Katsumi Mizushima 1-1-1, Showa-cho, Kariya-shi, Aichi F-term in DENSO Corporation (reference) 2F051 AA01 AB07 BA07 3B087 DE08 3D054 AA21 BB30 EE10 FF16

Claims (6)

[Claims] 1. A sensor mat having a plurality of sensor cells arranged on a plane and capable of detecting pressure independently of each sensor cell, wherein the sensor mat is incorporated in a lower part of a seat of a vehicle, An occupant discriminating system for detecting a distribution of a load applied to the seat surface of the seat from an output of the sensor cell, and discriminating whether an occupant on the seat is a child or an adult based on the load distribution, The vehicle according to any one of claims 1 to 3, further comprising a correction step of correcting a displacement of the load distribution due to a displacement of the sensor mat after the sensor mat is assembled and a seat cover that covers a seat surface of the seat is assembled. Occupant identification system. 2. An occupant discriminating system for an automobile according to claim 1, wherein, in the correcting step, an output signal from the sensor cell selected in advance is applied with a predetermined area on the seat surface of the seat skin. A displacement amount of the sensor mat is estimated based on the displacement amount, and the displacement of the load distribution is corrected according to the displacement amount. 3. The occupant discriminating system for a vehicle according to claim 2, wherein in the correcting step, at least two of the sensor cells arranged in a specific direction on the sensor mat are selected in advance, and the selection is made. An occupant discriminating system for an automobile, wherein a displacement amount of the sensor mat is estimated based on a signal output from the sensor cell, and the displacement of the load distribution is corrected according to the displacement amount. 4. The occupant discriminating system for an automobile according to claim 3, wherein the at least two sensor cells arranged in a specific direction on the sensor mat are in a front-rear direction or a left-right direction of the sensor mat. At least 2 in the target position
An occupant discriminating system for an automobile, comprising: the sensor cells. 5. The occupant discriminating system for an automobile according to claim 2, wherein in the correcting step, when the sensor mat is at a normal position, pressure is applied to the seat surface of the seat. The sensor cells arranged at positions deviating from a certain area are pre-selected, a position shift amount of the sensor mat is estimated based on a signal output from the selected sensor cell, and the load is determined according to the position shift amount. An occupant discriminating system for an automobile, which corrects a deviation in distribution. 6. The occupant discriminating system for an automobile according to claim 2, wherein in the correcting step, when the sensor mat is at a normal position, pressure is applied to the seat surface of the seat. The sensor cells arranged in a predetermined area are selected in advance, and the amount of displacement of the sensor mat is estimated based on a signal output from the selected sensor cell, and the displacement of the load distribution is determined in accordance with the amount of displacement. An occupant discriminating system for an automobile, characterized by correcting the following.