JP4522224B2 - Occupant detection device - Google Patents

Description

  The present invention relates to an occupant detection device that determines the state of an occupant seated on a vehicle seat using an output value of a load sensor.

  Conventionally, as shown in FIG. 6, a load sensor 4,... Is attached to a support portion 3,... That supports the seat 1, and an occupant who determines whether the occupant is an adult or a child is determined based on the output value. A detection device is known (see Patent Document 1).

  The seat 1 includes a seat cushion portion 1a that forms a seating surface and a seat back portion 1b that serves as a backrest, and each of the regions divided into four front, rear, left, and right regions has four locations. It is supported from below by the support portions 3.

  Further, the support portions 3,... Are slidably attached to the seat rails 2, 2, and load sensors 4,. As the load sensor 4, a strain type load sensor is used.

  Then, as shown in FIG. 7, the output values output from the four load sensors 4,... Are sent to the occupant determination unit 5, and the total of the output values is compared with the threshold value stored in the EEPROM 8. Is done.

  This threshold is a threshold for determining whether the occupant is an adult or a child. If the total output value is smaller than this threshold, it is determined that the occupant is a child. Determine that you are an adult.

The determination result is sent to the airbag control unit 6 and used for switching the deployment amount of the airbag 7. That is, when the occupant is an adult, the airbag 7 is deployed as normally set at the time of an accident, and when the occupant is a child, the deployment of the airbag 7 is suppressed or stopped.
JP 2004-122927 A (FIGS. 1 to 4)

  However, the conventional occupant detection device measures the occupant's load using the four load sensors 4,... On the seat 1 of one seat, but the load sensor 4 is not an inexpensive sensor. It is desirable to reduce the number of uses as much as possible.

  Then, this invention aims at providing the passenger | crew detection apparatus which can reduce cost by reducing the usage-amount of a load sensor.

  In order to achieve the above object, the invention according to claim 1 is characterized in that an output value of a load sensor provided in a support portion for supporting the seat is determined in advance in order to determine an occupant state seated on the seat of the vehicle. An occupant detection device having an occupant determination unit for comparison with a set threshold value, wherein load sensors are attached to three of the support portions respectively provided in the four regions before and after the plane view of the seat, An estimation unit is provided for estimating the load value of one support portion remaining from the output values of the three load sensors, and the occupant determination unit determines the occupant state based on the output value and the estimated load value calculated by the estimation unit. It is an occupant detection device that performs.

  Moreover, the thing of Claim 2 WHEREIN: The said occupant detection apparatus of Claim 1 with which the said load sensor was provided in two support parts of the said seat rear part, and one support part of the said seat front part. It is characterized by being.

  Further, according to a third aspect of the present invention, the estimation unit calculates the estimated load value by assuming that the front and rear load ratios are equal on the left and right of the seat. It is an occupant detection device.

  According to the first aspect of the present invention configured as described above, the load value of the support portion at one location where the load sensor is not attached is estimated from the output values of the load sensors attached at the three locations. And a passenger | crew's state is determined from this estimated load value and an output value.

  For this reason, one load sensor per sheet can be reduced as compared with the prior art, and the cost can be reduced by reducing material costs and assembly man-hours.

  In addition, the load sensors are distributed and arranged at three locations in the four areas before and after the plan view, and the remaining load values are estimated from the output values, so that the estimation error can be reduced. .

  According to the second aspect of the present invention, the load sensor at the front portion of the seat is omitted, and the load value at the omitted position is estimated. Here, since the load acting on the seat is usually larger in the rear portion than in the front portion, omitting the load sensor in the front portion of the seat that is less affected by errors hardly affects the determination result. The load sensor can be reduced.

  Further, according to the third aspect of the present invention, the estimated load value is calculated on the assumption that the load is distributed back and forth at the same load ratio on the left and right sides of the seat.

  Thus, the estimation error can be reduced by calculating the estimated load value using an arithmetic expression that is supported from actual data.

  The best mode for carrying out the present invention will be described below with reference to the drawings.

  FIG. 1 shows a configuration of an occupant detection device 10 according to the present embodiment.

  First, in terms of configuration, the occupant detection device 10 according to the present embodiment has load sensors 4A, 4B, 4C attached to three support portions 3, 3, 3 (see FIG. 2), and outputs thereof. And an occupant determination unit 12 that determines the state of the occupant from the value.

  As shown in FIGS. 2 to 4, the seat 1 is formed of a seat cushion portion 1a and a seat back portion 1b. 3 and 4, the seat 1 is attached to the seat rails 2 and 2 fixed in parallel to the vehicle interior floor via support portions 3, 11,.

  The support portions 3, 11,... Have support portions 3, 3, 3 attached with load sensors 4 A, 4 B, 4 C, and bolt support as a support portion for supporting the seat 1 without providing the load sensor 4. Part 11.

  These support parts 3,11, ... are attached to a seat frame (not shown) on the lower surface of the seat cushion part 1a, and are respectively arranged in four regions before and after the plan view as shown in FIG.

  In the present embodiment, a load sensor 4A is arranged on the front right side of the seat cushion part 1a, a load sensor 4B is arranged on the right side of the rear part, and a load sensor 4C is arranged on the left side of the rear part. The bolt support part 11 fastened to the seat 1 by a bolt without providing 4 is arranged.

  These support portions 3, 11,... Are configured to be slidable along the seat rails 2, 2, and passengers and seats transmitted from the seat 1 to the support portions 3, 11,. The load 1 is transmitted to the seat rails 2 and 2 through the support portions 3, 11,.

  Further, strain type load sensors are used as the load sensors 4A, 4B, and 4C, and output values proportional to the strain caused by the load acting on the support portions 3,... Are output.

  Furthermore, the occupant determination unit 12 of the present embodiment includes an estimation unit 13 that estimates the load value of the bolt support unit 11, the estimated load value estimated by the estimation unit 13, and the output values of the load sensors 4A, 4B, and 4C. And a determination unit 14 for determining the state of the occupant.

  The estimation unit 13 calculates an estimated load value by applying output values transmitted from the three load sensors 4A, 4B, and 4C to an arithmetic expression. This estimated load value is estimated as the load value of the bolt support portion 11.

  Then, the determination unit 14 compares the total of the three output values and one estimated load value with the threshold value stored in the EEPROM 15 as the storage unit to determine whether the occupant is an adult or a child. .

  The determination result of the occupant determination unit 12 is sent to the airbag control unit 6, and when it is determined that the occupant is a child, the occupant state display lamp 16 displays that the child is an occupant, The deployment of the airbag 7 is suppressed or stopped.

  When it is determined that the occupant is an adult, the airbag control unit 6 performs control so that the airbag 7 is deployed as normally set.

  Next, the operation of the occupant detection device 10 described above will be described with reference to the flowchart shown in FIG.

When the occupant sits on the seat 1 with the ignition key turned on, the three load sensors 4A, 4B, and 4C detect the load, and output the detected load as an output value (S1). Here, the load sensors 4A, 4B, the output value of 4C, respectively _{W A,} W B, and _{W C.}

Further, the output values W _A , W _B , and W _C are transmitted to the estimation unit 13 to calculate the estimated load value W _x of the bolt support unit 11 (S2). Here, it is assumed that in order to calculate the estimated load value W _x, the ratio of the load of the front and rear seat cushion 1a is the same in the left and right sides of the seat cushion 1a.

_{That, W A: W B = W} x: and _{W C.} Given _this, it is possible to obtain a _{W x = W C × W A} / W estimated load value _{W x} as _B.

Then, the estimated weight value W _x and the output values W _A , W _B , W _C are summed to calculate the weight W of the occupant (S3). Here, since the occupant is usually seated on the floor, the calculated weight W is smaller than the weight of the occupant.

  Therefore, the correlation between the calculated weight W and the weight of the adult is stored in advance as data, and the weight serving as the boundary between the adult and the child is stored in the EEPROM 15 as a threshold Th.

  The threshold value Th thus stored is compared with the calculated occupant weight W (S4). If the weight W on the seat 1 is greater than or equal to the threshold Th, it is determined that the adult is an occupant (S5). If the weight W on the seat 1 is less than the threshold Th, it is determined that the child is an occupant (S6).

  The determination result is sent to the airbag control unit 6 and used for controlling the airbag 7 and switching the occupant state display lamp 16.

In such passenger detecting device is configured 10, the load sensor 4A attached at three positions, 4B, the output value _W A of _4C, W B, the _{W C,} bolt support in one place the load sensor 4 is not attached The estimated load value W _x of the part 11 is calculated. Then, the estimated load value W _x and the output value W _A, W _B, the passenger and a W _C determines whether a child or an adult.

  For this reason, the occupant detection device 10 can be configured at low cost by reducing the material cost and the number of assembling steps, which can reduce one load sensor 4 per sheet as compared with the conventional case.

Further, the load sensors 4A, 4B, and 4C are distributed and arranged in three portions of each region divided into four regions before and after the plan view, and the output values W _A , W _B , and W _C. Since the remaining estimated load value W _x is calculated from, the estimation error can be reduced.

  Further, according to the result of analyzing the accumulated data of the load sensor 4, the occupant's weight acts on the rear part of the seat 1 by about 80% and only the front part by about 20%. Of these, when the load sensor 4 is omitted, the effect of the estimation error can be minimized. When the load sensor 4 at the two front portions of the seat 1 is omitted, the estimation error is reduced. The impact can be minimized.

  Further, since the load on the side of the seat 1 where the seat belt buckle is attached tends to increase, it is most preferable that the bolt support portion 11 is the front portion on the side where the seat belt buckle is not attached.

  In this way, the position where the load value is estimated without attaching the load sensor 4 is the position where the influence of the estimation error is minimized, so that the load sensor 4 can be reduced with little influence on the determination result of the occupant state. be able to.

Further, since the load is distributed in the front and rear at the same load ratio on the left side and the right side of the seat 1, the estimated load value W _x can be accurately calculated if the occupant is seated on the seat 1 in the correct posture. it can.

  Although the best embodiment of the present invention has been described in detail with reference to the drawings, the specific configuration is not limited to this embodiment, and design changes that do not depart from the gist of the present invention are possible. Are included in the present invention.

  For example, in the above-described embodiment, the estimation unit 13 is provided inside the occupant determination unit 12, but may be provided separately.

  Moreover, in the said embodiment, although the position which abbreviate | omits the load sensor 4 was made into the front left side of the sheet | seat 1, it is not limited to this, You may abbreviate | omit the load sensor 4 of any position.

Furthermore, in the said embodiment, although the support part in which the load sensor 4 was not provided was demonstrated as one place of the bolt support part 11, it is not limited to this, In addition to this, the load sensor 4 is There may be a support portion that is not provided. Even in this case, the estimated load value W _x of at least one support portion can be obtained.

Then, in the embodiment, the front and rear load ratio estimating conditions in the left and right seat 1 of the estimated load value W _x is the equal, it is not limited thereto, the load distribution by the structure of the seat 1 When different from the embodiment, it is possible to calculate the estimated load value W _x by using another arithmetic expression according to the embodiment.

  In the above-described embodiment, the threshold value is a value for discriminating between adults and children. However, the threshold value is not limited to this, and the size may be discriminated. Furthermore, a plurality of threshold values can be provided.

  In the embodiment, the strain type load sensors are used as the load sensors 4A, 4B, and 4C. However, the present invention is not limited to this, and for example, a hydraulic type load sensor can be used.

  In the above embodiment, the determination result is used for the control of the airbag 7. However, the present invention is not limited to this. For example, the presence or absence of an occupant is determined, and the seat belt is attached to the occupant. It can also be used for a device that lights a warning lamp only when it is not.

It is a block diagram explaining the structure of the passenger | crew detection apparatus of the best embodiment of this invention. It is the top view which showed the positional relationship of a sheet | seat and a load sensor. It is the front view which showed the positional relationship of a sheet | seat and a load sensor. It is the side view which showed the positional relationship of a sheet | seat and a load sensor. It is the flowchart which showed the flow of the process of a passenger | crew detection apparatus. It is a perspective view explaining the structure of the conventional passenger | crew detection apparatus. It is a block diagram explaining the structure of the conventional passenger | crew detection apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Seat 3 Support part 4 Load sensor 4A-4C Load sensor 10 Occupant detection apparatus 11 Bolt support part (support part)
12 occupant determination unit 13 estimation unit 14 determination unit

Claims (3)

An occupant detection device having an occupant determination unit that compares an output value of a load sensor provided in a support unit that supports the seat with a preset threshold value in order to determine an occupant state seated on a vehicle seat. And
A load sensor is attached to three of the support portions provided in the four regions before and after the plane view of the seat, and the load value of the remaining one support portion is estimated from the output values of the three load sensors. An occupant detection device, wherein the occupant determination unit determines an occupant state based on the output value and the estimated load value calculated by the estimation unit.   2. The occupant detection device according to claim 1, wherein the load sensors are provided at two support portions at a rear portion of the seat and at one support portion at the front portion of the seat. The occupant detection device according to claim 1, wherein the estimation unit calculates the estimated load value by assuming that front and rear load ratios are equal on the left and right sides of the seat.

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