JP2002087132A - Seating detection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a seating detection device capable of accurately judging that a person seats oneself on a seat. SOLUTION: A plurality of cells 13 for detecting a partial pressure X (i, j) defined by a line in a width direction and a row in a forward/rearward direction of a seating surface of the seat 12 arranged. A standard pressure TEMP (i, j) at the time when a person seats oneself on a seat is set in the respective cells 13. When a person adaptability based on a product sum of these partial pressures X (i, j) and the standard pressure TEMP (i, j) is below a predetermined person adaptability threshold value and an edge strength based on a sum of a difference size of an average value of these partial pressures X (i, j) and a partial pressure detected in the cell adjacent thereto exceeds a predetermined edge strength threshold value, a judgment standard value hantei corresponding to the number of ON cells is reduced and corrected. When this corrected judgment standard value hantei exceeds a predetermined number, it is judged that a person seats oneself on the seat 12.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a seating detection device for determining whether or not a person is sitting on a seat.

[0002]

2. Description of the Related Art In recent years, vehicles have been provided with an airbag device in front of the vehicle (driver's seat or passenger seat) for the purpose of improving safety in the event of a vehicle collision. When the vehicle collides due to an accident or the like, the airbag control device outputs a signal (activation signal) for igniting the inflator to the airbag actuator based on a signal from the collision detection sensor, and instantaneously outputs the airbag signal. Inflate.

[0003] As described above, among vehicles aimed at improving the safety of activating an airbag at the time of a vehicle collision, vehicles that switch the location where the airbag is activated according to the direction of collision are also on the market. In this case, it is necessary to accurately determine whether a person is sitting on the seat and activate the airbag. In particular, in the passenger seat, when a person (adult) is seated, when a child is seated, or when a child seat (hereinafter referred to as “CRS (Child Restraint Sy
Since various seat states are assumed, such as when the seat is mounted), it is desired to accurately determine whether or not a person is sitting on the seat.

[0004]

Various seating detecting devices for determining whether or not a person is seated on a seat have been proposed. For example, a plurality of cells for detecting a partial pressure defined by rows in the width direction and columns in the front-rear direction of the seating surface of the seat are arranged on the seating surface, and based on the partial pressures detected by these cells, a person A device that determines whether or not a person is seated is known.

[0005] For example, Japanese Patent Application No. 11-365753 proposes a seating detection device using such a cell. This seating detection device determines whether or not a person is seated on a seat by template matching of a pressure addition value obtained by adding the partial pressure detected in each cell in the width direction. That is, a template of each pressure addition value in a state where the person is properly seated and the person is in the front sitting state is created, and this is compared with the pressure addition value of the detected partial pressure, so that the person is placed on the seat. It is determined whether the user is seated or the CRS is mounted.

However, the physique and sitting posture of a person are various, and the judgment is made only in a limited state using only the template in each of the above states. On the other hand, it is conceivable to increase the number of templates to be referenced correspondingly, but in this case, another problem such as an increase in storage capacity and an increase in calculation load occurs.

In the above-mentioned application, it is also determined whether or not a person is seated on a seat based on a variation (differential value) of a pressure addition value obtained by adding a partial pressure detected in each cell in the front-rear direction. I have.

However, depending on the shape of the sheet, there is a difference in the sensitivity of pressure detection between the central portion and the peripheral portion, or the fluctuation of the added pressure value increases when a person leans on the door, resulting in an erroneous determination. It may be done.

An object of the present invention is to provide a seating detection device that can more accurately determine that a person is sitting on a seat.

[0010]

In order to solve the above-mentioned problems, the invention according to claim 1 is provided on a seating surface of a seat, wherein the seating surface is formed by rows in a width direction and columns in a front-rear direction. A plurality of cells for detecting a prescribed partial pressure; ON cell number detecting means for detecting the number of ON cells which is the number of cells where the detected partial pressure exceeds a predetermined pressure; and a person sitting on the seat. The human pressure, which calculates the human fitness based on the sum of the reference pressure template in which the reference pressure for each cell is set and the partial pressure detected for each cell and the reference pressure of the corresponding cell. Calculating means, ON cell number correcting means for reducing and correcting the number of ON cells when the calculated degree of human conformity falls below a predetermined human conformity threshold, and wherein the corrected number of ON cells exceeds a predetermined number. When a person sits on the seat And gist that a the determination means is.

According to a second aspect of the present invention, in the seating detection device according to the first aspect, the reference pressure of each cell is set so that an average value thereof is substantially zero. The invention according to claim 3, wherein a plurality of cells disposed on the seating surface of the seat to detect a partial pressure defined by rows in the width direction and columns in the front-back direction of the seating surface, and the detected portion O, the number of cells whose pressure exceeds a predetermined pressure
ON cell number detecting means for detecting the number of N cells, and an edge based on a sum of differences between a partial pressure detected for each cell and an average value of partial pressures detected in cells adjacent to the cell. Edge strength calculating means for calculating the strength;
ON cell number correction means for reducing and correcting the number of ON cells when the calculated edge strength exceeds a predetermined edge strength threshold value; and a sheet when the corrected number of ON cells exceeds a predetermined number. And determining means for determining that a person is seated.

[0012] The invention according to claim 4 is the invention according to claim 1 or 2.
In the seating detection device according to (1), the edge for calculating the edge strength based on the sum of the magnitude of the difference between the partial pressure detected for each cell and the average value of the partial pressures detected in cells adjacent to the cell The invention is characterized in that it comprises a strength calculating means, and wherein the ON cell number correcting means further reduces and corrects the number of ON cells when the calculated edge strength exceeds a predetermined edge strength threshold value.

The invention according to claim 5 is the invention according to claim 3 or 4.
In the seating detection device described in the above, the edge strength calculation means calculates the sum of the magnitude of the difference between the partial pressure detected for each cell and the average value of the partial pressures detected in cells adjacent to the cell. The gist is to calculate the edge strength by dividing either one of the sum of the detected partial pressures and the detected number of ON cells.

The invention according to claim 6 is the invention according to claims 1, 2, and
4. In the seating detection device according to any one of the items 4, the determination unit determines that the calculated degree of human conformity is lower than a predetermined human conformity threshold when it is determined that no person is seated on the seat. The gist is that it is determined that the child seat is sometimes worn, and that the child is seated when the child seat threshold is exceeded.

(Action) Rows (i) in the width direction of the seating surface of the seat
Suppose that cells for detecting pressures are respectively arranged in a plurality of portions defined by rows (rows) and columns (j columns) in the front-rear direction, and the partial pressures X (i, j) are detected by these cells.
At this time, if a load is applied, such as a person sitting on the seat, the detected partial pressure X
ON where (i, j) is the number of cells exceeding a predetermined pressure
The number of cells reaches a certain number. Therefore, it is conceivable to detect that a person is seated on the seat using the ON cell number reaching a certain number as one measure.

However, for example, even if the number of ON cells is the same, if a person is seated on the seat,
In some cases, the RS is mounted. FIG. 7 shows the partial pressure X detected in 80 cells arranged on the sheet in 7 rows × 12 columns (excluding four cells at both ends at the rear of the sheet).
(I, j) is shown as an example. As shown in FIG. 7, when a person is sitting on the seat (FIG. 7).
(A)) and when the CRS is mounted (FIG. 7 (b))
And shows different characteristics in the distribution of the detected partial pressure X (i, j) on the sheet. That is, when a person is seated on the seat, a certain level of partial pressure is detected in a cell relatively from the center, while when a CRS is mounted, a certain level of partial pressure is detected in a cell from the periphery. Is detected. In other words, the partial pressures X (i, j) detected by the plurality of cells show a tendency that the distributions of the partial pressures X (i, j) are inverted when the person is seated on the seat and when the CRS is mounted. . Therefore, for example, as shown in FIG. 6, each state when a person is seated on the seat (for example, a state where an adult is properly seated, a state where an adult is leaning against a door, (A state in which the seat is seated with the seat folded down on the back), and a reference pressure TEMP (i, j) for each cell which can tend to suppress the tendency of CRS obtained from experimental values. Create a pressure template TP. This reference pressure template TP corresponds to the above-described example, and has a reference pressure TEMP (i, i,
j) shows the distribution.

The partial pressure X (i, i,
j) and the product sum of the reference pressure TEMP (i, j) of the corresponding cell. At this time, if the partial pressure X (i, j) detected for each of these cells and the reference pressure TEMP (i, j) of the corresponding cell show the same tendency, the states are multiplied and sum of products is calculated. , On the other hand, if it shows an inverted tendency, the state is reflected so as to suppress the increase in the sum of products. Therefore, the calculated level (size) of the sum of products can be used as a degree of human conformity as a reference for determining that a person is seated on the seat.

As shown in FIG. 7, when the CRS is mounted as compared with the case where a person is seated on the seat, the partial pressure X (i, i,
A sharp pressure fluctuation (edge) is recognized between j) and the partial pressure detected in a cell adjacent to the cell.
This is because the CRS, which is a structural body, is harder than a soft human body, and is significantly tightened and fixed by a seat belt, so that significant pressure fluctuation occurs at the contact portion. Accordingly, when determining that a person is seated on the seat, the partial pressure X detected in the predetermined cell is determined.
The level (magnitude) of pressure fluctuation between (i, j) and the partial pressure detected in a cell adjacent to the cell can be used as a reference for determining that a person is sitting on the seat. .

According to the first aspect of the present invention, the degree of human fitness is calculated based on the product sum of the partial pressure detected for each cell and the reference pressure of the corresponding cell. When the number falls below the predetermined person adaptation threshold value, the number of ON cells is reduced and corrected accordingly, since it is not the tendency when a person is sitting on the seat. Since it is determined that a person is seated on the seat based on the corrected number of ON cells, the determination accuracy is increased.

According to the second aspect of the present invention, the reference pressure for each cell is set so that the average value is substantially zero. Therefore, when calculating the above-mentioned degree of human conformity (sum of products) in such a setting, if the tendency is the same as that when a person is seated on the seat, it is added as a positive number and the tendency is inverted. If present, it is added as a negative number. If the tendency is similar to that when a person is sitting on the seat as a whole, the above-mentioned person suitability is a positive number,
If it shows the reversal tendency, it will be a negative number. That is, the polarity is evaluated on the basis of zero, and if the degree of human conformity is a positive number, the person tends to be seated on the seat, and if the degree of negativeness is a negative number, the tendency tends to be different. This is a calculation method.

According to the third or fourth aspect of the present invention, the sum of the magnitude of the difference between the partial pressure detected for each cell and the average value of the partial pressures detected in cells adjacent to the cell is calculated. When the calculated edge strength exceeds a predetermined edge strength threshold value, it is determined that the tendency is not that in the case where a person is seated on the seat, and the number of ON cells is reduced accordingly. Will be corrected. And
Since it is determined that a person is sitting on the seat based on the corrected number of ON cells, the determination accuracy is increased.

According to the fifth aspect of the present invention, the edge strength is the difference between the partial pressure detected for each cell and the average value of the partial pressures detected in cells adjacent to the cell. The sum is calculated by dividing either the sum of the detected partial pressures or the detected number of ON cells.
Generally, when a person (adult) is sitting on the seat,
Even if there is a gradual change in pressure as a whole, the difference between the partial pressure detected for each cell described above and the average value of the partial pressures detected in the cells adjacent to the same cell because of the wide contact portion is described. The sum of the sizes increases accordingly. On the other hand, when the CRS is mounted, even if the pressure fluctuates sharply, the partial pressure detected for each cell described above and the cells adjacent to the same cell are detected due to the narrow contact portion. The total sum of the magnitude of the difference from the average value of the partial pressures is suppressed accordingly. Therefore, CRS
Even if is mounted, depending on the area of the contact portion or the characteristics of the pressure fluctuation, the partial pressure detected for each cell and the average value of the partial pressures detected in cells adjacent to the cell described above The sum of the magnitudes of the differences is the same as when a person (adult) is seated on the seat.
The edge strength is calculated by dividing such a sum by either one of the sum of the detected partial pressures and the detected number of ON cells. Therefore, the influence of the area of the contact portion is absorbed as a whole. Is done.

According to the sixth aspect of the present invention, when it is determined that no person is seated on the seat, the CRS is calculated when the calculated degree of human conformity is lower than the predetermined human conformity threshold. Is determined to be worn, and it is determined that the child is seated when the predetermined person matching threshold is exceeded. In general, even if a child is seated on the seat, the distribution of the detected partial pressure is similar to that of a person (adult), and thus the above-described degree of human fitness also shows a similar tendency. Therefore, when it is determined that a person (adult) is not seated on the seat, the CRS is attached or the child is seated by comparing the calculated degree of human fitness with a predetermined human fitness threshold. Is detected. Thereby, more suitable control according to the state of the sheet can be performed.

[0024]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a seating detection device embodying the present invention will be described below with reference to FIGS.

FIG. 1 is a block diagram showing an electrical configuration when the seating detection device 1 is applied to a vehicle. As shown in FIG. 1, the seating detection device 1 mainly includes a pressure sensor 10 and a controller 11.

As shown in FIG. 2, the pressure sensor 1
0 is accommodated in the seating surface of the vehicle seat (seat cushion) 12, and is a row (i row) in the width direction (x direction) and a column (j column) in the front-rear direction (y direction) of the vehicle seat 12. )
A well-known pressure detecting cell 1 at each position defined by
3 is provided. These cells 13
The pressure (partial pressure) X (i, j) at the position is detected. These detected partial pressures X (i, j) are:
Each is input to the controller 11.

In the present embodiment, the vehicle seat 12
A partial pressure X is obtained by 80 cells 13 (removing 4 cells at both ends behind the sheet 12) arranged in 7 rows × 12 columns on the upper side.
The case where (i, j) is detected will be described, but this is an example and the present invention is not limited to this.

The controller 11 includes a CPU (central processing unit) 21, a power supply circuit 22, a first switching circuit 23,
A second switching circuit 24, an A / D (analog / digital) conversion circuit 25, and an output circuit 26 are provided.

The CPU 21 determines the seating state of the vehicle seat 12 according to a control program and initial data stored in a ROM (read-only memory) in advance. The power supply circuit 22 converts a power supply (for example, 12 V) supplied from a battery (not shown) to a predetermined voltage (for example, 5 V).
V) and supply it as power for the CPU 21.

The first and second switching circuits 23 and 24 are connected to the pressure sensor 10 and selectively switch the rows and columns of the pressure sensor 10 in response to a switching signal from the CPU 21 to detect each of the cells 13. The obtained partial pressures X (i, j) are sequentially input to the A / D conversion circuit 25.
These partial pressures X (i, j) are converted from analog signals to digital signals in the A / D conversion circuit 25,
It is input to PU21. Then, the partial pressure X (i, j) and the partial pressure X (i, j) detected in each cell 13
The number of ON cells in which j) is the number of cells exceeding a predetermined pressure
on_cel is individually temporarily stored in the memory and is used by the CPU 21 to determine the seating state of the vehicle seat 12 and the like.

The output circuit 26 is connected to the CPU 21 and outputs the seating state of the vehicle seat 12 determined by the CPU 21. This output circuit 26
Is an airbag ECU (Electronic Control Unit) 30
The seating state of the vehicle seat 12 determined by the CPU 21 is output to the airbag ECU 30 as a seating signal.

The airbag ECU 30 activates an inflator, if necessary, based on a seating signal and a signal from a collision sensor (not shown) (operation signal).
To the airbag actuator to instantaneously inflate the airbag in the driver's seat or the passenger's seat.

In particular, when an adult is seated on the vehicle seat 12 in the passenger seat, when a child is seated, the CRS
Is installed, nothing may be present, and the airbag ECU 30 suitably controls the operation of the airbag in the passenger seat by inputting a seating signal corresponding to each case.

FIGS. 3 and 4 show that the vehicle seat 12 has a CR.
It shows an example of a detection result (pressure distribution) by the pressure sensor 10 (cell 13) when S is worn, when a child is sitting, and when an adult is sitting. That is, FIGS. 3A to 3C show CRS (CRS1 to CRS).
FIG. 3D to FIG. 3F show the pressure distribution when three types (S3) are mounted, and children (three types) are attached to the vehicle seat 12.
4 (g) shows the pressure distribution when an adult is properly seated, and FIG. 4 (h) shows the pressure distribution when an adult is sitting leaning on a door. And FIG.
(I) shows the pressure distribution when an adult sits backing the seat. In each figure, the horizontal axis represents the width direction of the sheet 12, the vertical axis represents the front-back direction of the sheet 12, and the numerical value shown on each axis represents the position of the cell 13. On the right side of each detection result, a legend indicating the magnitude of the load (partial pressure) detected in each cell 13 is shown.

As is clear from FIGS. 3 and 4, each pressure distribution has its own characteristics, which suggests that the above cases can be determined. Hereinafter, the content of the process executed by the controller 11 and the occupant determination mode of the seating detection device according to the present embodiment will be described with reference to FIGS.

The routine shown in the flowchart of FIG.
It is executed by a periodic interruption every predetermined time. When shifting to this routine, the CPU 21 firstly proceeds to step 101.
In, various data such as all partial pressures X (i, j) detected by the pressure sensor 10 (cell 13) are read, and the process proceeds to step.

In step 102, the CPU 21 determines whether or not the ON cell number on_cel, which is the number of cells in which the detected partial pressure X (i, j) exceeds a predetermined pressure, is equal to or greater than a predetermined threshold value XX. In general, the vehicle seat 12
When a child is sitting or wearing a CRS, the load causes the number of ON cells on_cel to reach a certain number. The predetermined threshold value XX is used to largely divide a case where a person or a child is seated on the vehicle seat 12 or a case where the CRS is attached and a case where nothing exists.

Here, when it is determined that the number of ON cells on_cel is less than the predetermined threshold value XX, the CPU 21 determines that a person or child is seated on the vehicle seat 12 or that the CRS
It is determined that there is no load when is mounted, and the process proceeds to step 103. And step 10
In 3, it is determined that there is nothing in the vehicle seat 12, and the subsequent processing is temporarily terminated.

On the other hand, in step 102, the number of ON cells
When it is determined that on_cel is equal to or greater than the predetermined threshold value XX, C
The PU 21 determines that a person or a child is seated on the vehicle seat 12 or that the CRS is mounted, and proceeds to step 104.

In step 104, the CPU 21 determines whether or not the number of ON cells on_cel is equal to or larger than a predetermined threshold value A. Generally, when a certain load (for example, 80 kg) is applied to the vehicle seat 12, there is a high possibility that a person (adult) is seated on the vehicle seat 12. And when such a large load is applied,
Correspondingly, the ON cell number on_cel increases. The predetermined threshold value A is for roughly classifying a state in which there is a high possibility that a person (adult) is seated in the vehicle seat 12 and a state in which the person (adult) is low.

If it is determined that the number of ON cells on_cel is equal to or larger than the predetermined threshold A, the CPU 21 proceeds to step 10.
5 and the judgment reference value hantei is set to the number of ON cells on_cel.
Is set to a value doubled, and the routine goes to step 107.
When it is determined that the number of ON cells on_cel is less than the predetermined threshold value A, the CPU 21 proceeds to step 106, sets the determination reference value hantei as it is to the number of ON cells on_cel, and proceeds to step 107. In addition, this judgment reference value
The final value of hantei is used to determine the state of the vehicle seat 12. As described above, when the number of the ON cells on_cel increases, the possibility that a person (adult) is seated on the vehicle seat 12 increases. Step 104
When the number of ON cells on_cel is large, the processing of steps 106 to 106 is set so that the determination reference value hantei is set to a large value so that it is possible to more reliably determine that a person (adult) is sitting on the vehicle seat 12. It is for doing.

In step 107, the CPU 21 determines the degree of human fitness TEMP_HIT. This human fitness TE
MP_HIT will be described below. As shown in FIG. 7, when a person is seated on the vehicle seat 12 (FIG. 7).
(A)) and when the CRS is mounted (FIG. 7 (b))
In the sheet 12 of the detected partial pressure X (i, j)
In the above distribution, different characteristics are shown. That is, when a person is seated on the vehicle seat 12, a partial pressure of a certain level is detected in the cell 13 relatively from the center, while when a CRS is mounted, a cell from the periphery is detected. At 13, some level of partial pressure is detected. In other words, a plurality of cells 1
The partial pressure X (i, j) detected by 3 indicates a tendency that the distribution is reversed between the case where the person is seated on the vehicle seat 12 and the case where the CRS is mounted. Therefore, in the present embodiment, for example, as shown in FIG. 6, each case where a person is seated on the vehicle seat 12 (see FIGS. 3 (d) to (f) and FIGS. 4 (g) to (i)) ), And the reference pressure TEM for each cell 13 that can tend to suppress the tendency of CRS obtained from experimental values.
A reference pressure template TP in which P (i, j) is set is created and stored in the ROM. This reference pressure template TP corresponds to the shape of the pressure sensor 10 and has a reference pressure TEMP (i, j) in an arrangement of 7 rows × 12 columns.
Is shown. Then, the average value of the reference pressures TEMP (i, j) set for each of the cells 13 is set to be a value “0” (in FIG. 6,
For convenience, the pressure is shown as an actual equivalent pressure).

In the present embodiment, the product sum of the partial pressure X (i, j) detected for each cell 13 and the reference pressure TEMP (i, j) of the corresponding cell 13 is calculated by the following equation (1). Calculate as TEMP_HIT.

[0044]

(Equation 1) At this time, the partial pressure X (i, j) detected for each of the cells 13 and the reference pressure TEMP of the corresponding cell 13
If (i, j) shows the same tendency, it is reflected as a positive number in the increase of the human fitness TEMP_HIT, and if it shows an inverted trend, it is reflected as a negative number in the reduction of the human fitness TEMP_HIT. Therefore, the finally calculated human fitness TEMP
Whether the overall result between the detection result of the pressure sensor 10 and the reference pressure template TP is similar or inverted is detected depending on whether _HIT is a positive number or a negative number. That is, the polarity (positive number or negative number) of the human fitness TEMP_HIT indicates whether or not a person is sitting on the vehicle seat 12.

In step 107, the degree of human fitness TEMP_HIT
Is determined to be a negative number, the CPU 21 proceeds to step 1
08 and updating a value obtained by subtracting a predetermined number crs1 from the judgment reference value hantei as a new judgment reference value hantei,
Move to step 109. On the other hand, if it is determined that the human suitability TEMP_HIT is equal to or greater than the value “0” as the predetermined human suitability threshold, the CPU 21 proceeds to step 109 without updating the determination reference value hantei.

When the overall tendency between the detection result of the pressure sensor 10 and the reference pressure template TP is reversed, the processing of steps 107 and 108 is determined by the judgment reference value.
This is because hantei is reduced so that it can be more reliably determined that the CRS is mounted on the vehicle seat 12.

In step 109, the CPU 21 determines the edge strength edge_sum. The edge strength edge_sum will be described below. As shown in FIG. 6, when the CRS is mounted compared to when a person is sitting on the vehicle seat 12, the partial pressure X (i, j) detected in the predetermined cell 13 and A sharp pressure change (edge) is observed between the partial pressure detected in the cell adjacent to the cell 13 and the partial pressure. This is because the CRS, which is a structural body, is harder than a soft human body, and is significantly tightened and fixed by a seat belt, so that significant pressure fluctuation occurs at the contact portion. Therefore, depending on the degree of the pressure fluctuation, the vehicle seat 12
It is suggested that the CRS is attached to the.

In the present embodiment, the edge strength edge_sum is calculated to represent such a pressure fluctuation. In this calculation, first, the difference ΔX (i, j) between the partial pressure X (i, j) detected for each cell 13 and the average value of the partial pressures detected in cells adjacent to the cell 13 is calculated. The size is calculated for all cells 13. As shown in FIG. 8, basically, a predetermined cell 13 (partial pressure X
(I, j)) and 4 adjacent thereto in the width direction and the front-back direction.
The difference ΔX (i, j) is calculated for one cell based on the following equation.

ΔX (i, j) = X (i, j) − (X (i−1, j) + X (i
+ 1, j) + X (i, j-1) + X (i, j + 1)) / 4 Further, for example, as shown in FIG. If there is only one,
The difference ΔX (i, j) is calculated based on the following equation.

ΔX (i, j) = X (i, j) − (X (i−1, j) + X (i
+ 1, j) + X (i, j + 1)) / 3 Note that the above-described difference ΔX (i, j) is similarly applied to the cells 13 arranged on the right, upper, lower peripheral portions, and the like. Is calculated.

Further, for example, when there are only two adjacent cells such as the cell 13 arranged at the upper left corner in FIG. 8, the difference ΔX (i, j) is calculated based on the following equation. .

ΔX (i, j) = X (i, j) − (X (i + 1, j) + X (i, j + 1)) / 2 Note that the lower left side, the upper right side, and the lower right side Similarly, the difference ΔX (i, i,
j) is calculated.

When the magnitude of the difference ΔX (i, j) is calculated for all the cells 13 in this manner, the following equation (2) is obtained.
These are summed up by the formula to calculate the total edge strength edge.

[0054]

(Equation 2) Further, the edge strength edge_sum is calculated by dividing the total edge strength edge by the total pressure sum which is the sum of the partial pressures X (i, j) detected in all the cells 13.

Edge_sum = edge / sum Note that the edge strength may be calculated by dividing the entire edge strength edge by the number of on cells detected at this time, on_cel.

Generally, when a person (adult) is seated on the vehicle seat 12, even if the pressure fluctuates gently as a whole, the entire edge strength edge is reduced by that much because the contact portion is wide. , Increase. On the other hand, when the CRS is mounted, even if the pressure fluctuates rapidly, the increase in the entire edge strength edge is suppressed by that much because the contact portion is narrow. Therefore, even when the CRS is mounted, the total edge strength edge is equal to that when a person (adult) is seated on the vehicle seat 12 depending on the area of the contact portion or the characteristics of the pressure fluctuation. Would.
In order to absorb the influence of the area of the contact portion as a whole, the edge strength edge_sum is calculated in the above-described manner.

In step 109, edge strength edge_s
If it is determined that um is equal to or greater than the predetermined edge strength threshold B, the CPU 21 proceeds to step 110 and updates a value obtained by subtracting a predetermined number crs2 from the determination reference value hantei as a new determination reference value hantei, Move to step 111. On the other hand, when it is determined that the edge strength edge_sum is less than the predetermined edge strength threshold B, the CPU 21
The process directly proceeds to step 111 without updating the hantei.

In the processing of steps 109 and 110, when the edge strength edge_sum is large and the pressure fluctuation is large, the judgment reference value hantei is reduced accordingly, and especially the vehicle seat 12 is reduced.
The reason is that it is possible to more reliably determine that the CRS is attached to the camera.

In step 111, the CPU 21 determines whether or not the determination reference value hantei is equal to or greater than a predetermined number ZZ. Here, when the determination reference value hantei is determined to be equal to or greater than the predetermined number ZZ, the CPU 21 determines that the characteristics indicate that an adult is seated on the vehicle seat 12, and proceeds to step 112. Then, in step 112,
It is determined that an adult is sitting on the vehicle seat 12, and the subsequent processing is temporarily terminated.

On the other hand, if it is determined in step 111 that the determination reference value hantei is smaller than the predetermined number ZZ, CP
U21 determines that the child is seated on the vehicle seat 12 or indicates that the CRS is mounted, and the process proceeds to step 113.

In step 113, the CPU 21 determines whether or not the human fitness TEMP_HIT at this time is equal to or greater than a value "0". Here, if it is determined that the human fitness TEMP_HIT is equal to or greater than the value “0”, the CPU 21 determines that the characteristic indicates that a person (child) is seated on the vehicle seat 12, and proceeds to step 114. I do. Then, in step 114, it is determined that the child is seated on the vehicle seat 12, and the subsequent processing is temporarily terminated.

In step 113, the human fitness TE
If it is determined that MP_HIT is a negative number, the CPU 21 determines that the characteristic indicates that the CRS is mounted on the vehicle seat 12, and proceeds to step 115. And
In step 115, it is determined that the CRS is mounted on the vehicle seat 12, and the subsequent processing is temporarily terminated.

The CPU 21 performs steps 103, 112,
The determination results at 114 and 115 are output to the airbag ECU 30 via the output circuit 26 as a seating signal. As described above, the airbag ECU 30 suitably controls the operation of the airbag in the passenger seat by inputting the seating signal.

FIG. 9 shows FIGS. 3A to 3F and FIG.
7 is a graph showing a list of calculation results such as determination values calculated in the above routine for each of the cases shown in FIGS. That is, FIG. 9A shows the total pressure sum corresponding to the total load in each case described above, and FIG.
The number of cells on_cel is shown in FIG.
FIG. 9D shows the coterie matching degree TEMP_HIT, and FIG. 9E shows the same judgment reference value hantei.

As shown in FIG. 9 (e), depending on whether or not the final judgment reference value hantei is equal to or greater than a predetermined number ZZ, a state where an adult is seated on the vehicle seat 12 and a state other than that ( (A state in which a child is seated on the vehicle seat 12 and a state in which the CRS is mounted)).

Further, as shown in FIG. 9D, the state in which a child is seated on the vehicle seat 12 or the CRS
In a state in which a child is seated on the vehicle seat 12 and a state in which the CRS is mounted, the state is substantially clear except for the case of the CRS 3 in which the pressure distribution is similar to that of a person due to the polarity of the human fitness TEMP_HIT. State is classified. As described in detail above, according to the present embodiment, the following effects can be obtained.

(1) In this embodiment, the human fitness TEMP_HIT
Is smaller than the value "0" as the predetermined person adaptation threshold, the judgment reference value hantei is reduced by the predetermined number crs1 accordingly, because it is not the tendency when a person is seated on the vehicle seat 12. Corrected. Then, it is determined that a person is seated on the vehicle seat 12 based on the corrected determination reference value hantei, so that the determination accuracy can be increased.

(2) In the present embodiment, the average value of the reference pressure TEMP (i, j) for each of the cells 13 is set to be “0”. Therefore, in such a setting, the human fitness TEMP_HIT becomes a positive number if it is similar to the tendency when a person is seated on the vehicle seat 12 as a whole. If it is, it will be a negative number. That is, the polarity is evaluated based on the value “0”, and if the degree of human fitness TEMP_HIT is a positive number, the vehicle seat 12
It is sufficient to judge that the person is seated at a different position if the number is negative, so that a simple calculation method can be used.

(3) In the present embodiment, the human fitness TEMP_HIT can be determined only by one template TP, and the storage capacity and the calculation load can be reduced. (4) In the present embodiment, when the edge strength edge_sum is equal to or greater than the predetermined edge strength threshold value B, the judgment reference value hantei is determined to be that which is not the tendency when a person is seated on the vehicle seat 12. Reduction correction was performed by a predetermined number crs2.
Then, to determine that a person is seated on the vehicle seat 12 based on the corrected determination reference value hantei,
The accuracy of the determination can be increased.

(5) In the present embodiment, the entire edge strength edge
Is divided by the sum pressure sum to calculate the edge strength edge_sum. Therefore, the influence of the area of the contact portion with the vehicle seat 12 can be absorbed as a whole, and the degree of pressure fluctuation can be detected more accurately. The same effect can be obtained when the edge strength is calculated by dividing the entire edge strength edge by the number of ON cells on_cel.

(6) In the present embodiment, the vehicle seat 12
When it is determined that no human (adult) is seated, the CRS is determined to be mounted if the human fitness TEMP_HIT is a negative number, and the child is seated if the value is equal to or greater than “0”. Can be determined. Thereby, more suitable control according to the state of the vehicle seat 12 becomes possible. Note that the embodiment of the present invention is not limited to the above-described embodiment, and may be modified as follows.

In the above-described embodiment, the number of ON cells is determined based on whether the vehicle seat 12 is occupied by a person or a child or a CRS is mounted, and when there is nothing.
On_cel is broadly divided based on, for example, total pressure su
m.

In the above embodiment, the number of ON cells is on
When the number of _cels is large, the determination reference value hantei is set to be large accordingly, so that it is possible to more reliably determine that a person (adult) is sitting on the vehicle seat 12. Instead, when the sum pressure sum is large, the judgment reference value is
You may make it set hantei large. Further, such processing may be omitted.

In the above embodiment, the average value of the reference pressure TEMP (i, j) for each cell 13 is set to be “0”. For example, the average value is equal to the partial pressure X (i, j). A setting having a reference value may be used. Also in this case, the partial pressure X detected for each of these cells 13
(I, j) and the corresponding cell reference pressure TEMP (i, j)
If j) shows a similar tendency, the state is synergistically reflected in the increase of the human fitness TEMP_HIT, while if it shows a reversed trend, the state is the human fitness TEMP_HIT
Is reflected so as to suppress the increase in Therefore, a comparison with a state in which a person is seated on the vehicle seat 12 can be similarly performed based on the human fitness TEMP_HIT calculated in such a setting. Note that the reference value of the partial pressure X (i, j) may be set such that the average value of the partial pressures X (i, j) detected for each cell 13 becomes a value “0”.

In the above embodiment, the predetermined cell 13
Adjacent cells in the width direction and in the front-rear direction were employed as adjacent cells for comparing the degree of pressure fluctuation. Alternatively or additionally, for example, cells adjacent in a diagonal direction may be employed.

[0076]

As described in detail above, according to any one of the first to sixth aspects, it is possible to more accurately determine that a person is sitting on a seat.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an electrical configuration of an embodiment of the present invention.

FIG. 2 is a plan view showing the pressure sensor of the embodiment.

FIG. 3 is an example diagram showing a detection result (pressure distribution) by a pressure sensor.

FIG. 4 is an example diagram showing a detection result (pressure distribution) by a pressure sensor.

FIG. 5 is a flowchart showing a control mode of the embodiment.

FIG. 6 is a map showing a template.

FIG. 7 is an example diagram showing a detection result (pressure distribution) by a pressure sensor.

FIG. 8 is an explanatory diagram showing a calculation mode of edge strength.

FIG. 9 is a list showing various calculation results and the like of the embodiment.

[Explanation of symbols]

 Reference Signs List 1 Seating detection device 10 Pressure sensor 11 Controller 13 Cell 12 Vehicle seat TP Reference pressure template

Claims (6)

[Claims] 1. A plurality of cells disposed on a seating surface of a seat for detecting a partial pressure defined by a row in a width direction and a column in a front-back direction of the seating surface, and wherein the detected partial pressure is a predetermined pressure. ON cell number detection means for detecting the number of ON cells, which is the number of cells exceeding, a reference pressure template that sets a reference pressure for each cell when a person is seated on the seat, Means for calculating the degree of human fitness based on the product sum of the detected partial pressure and the reference pressure of the corresponding cell; and when the calculated degree of human fitness falls below a predetermined level of human fitness. And a determination means for determining that a person is seated on the seat when the corrected number of ON cells exceeds a predetermined number. Seating detection device characterized by the following 2. The seating detection device according to claim 1, wherein the reference pressure for each cell is set so that an average value thereof is substantially zero. 3. A plurality of cells disposed on a seating surface of a seat for detecting a partial pressure defined by a row in a width direction and a column in a front-back direction of the seating surface, and wherein the detected partial pressure is a predetermined pressure. ON cell number detection means for detecting the number of ON cells, which is the number of cells exceeding, the partial pressure detected for each cell, and the average value of the partial pressure detected in cells adjacent to the cell Edge strength calculating means for calculating the edge strength based on the sum of the differences, and ON cell number correcting means for reducing and correcting the number of ON cells when the calculated edge strength exceeds a predetermined edge strength threshold value And a determining means for determining that a person is seated on the seat when the corrected number of ON cells exceeds a predetermined number. 4. The seating detection device according to claim 1, wherein a magnitude of a difference between a partial pressure detected for each cell and an average value of partial pressures detected in cells adjacent to the cell. Edge strength calculating means for calculating an edge strength based on the sum of the above, wherein the ON cell number correcting means further reduces the number of ON cells when the calculated edge strength exceeds a predetermined edge strength threshold value. A seating detection device characterized by correcting. 5. The edge strength calculating means detects a sum of differences between a partial pressure detected for each cell and an average value of partial pressures detected in cells adjacent to the cell. Sum of the partial pressures and the detected O
The seating detection device according to claim 3, wherein the edge strength is calculated by dividing one of the N cells. 6. The seating detection device according to claim 1, wherein the determination unit determines that the calculated degree of human conformity is determined when it is determined that a person is not seated on the seat. Is determined to be attached to the child seat when the value is below the predetermined person adaptation threshold, and is determined to be a child seated when the value exceeds the predetermined person adaptation threshold. Seating detection device.