JP4150824B2 - Occupant discrimination sheet and occupant discrimination control method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an occupant discrimination sheet that can assist airbag control that performs deployment control in accordance with, for example, the difference in occupant size.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, in order to properly control airbags and take-up of seat belts in an automobile, there is one that detects a load of an occupant seated on a seat (for example, Japanese Patent Application Laid-Open No. 2001-180353, Japanese Patent Application Laid-Open No. 2001-180353). Application 2000-240538). In addition, as a means for detecting a load in a seat, for example, a mat-like shape in which a strain sensor such as a load cell that detects a minute strain of metal is provided in a vehicle body mounting portion or a seat rail portion of the seat or a plurality of pressure sensors are arranged. Some things are placed under the seat cushion, and the load distribution acting on the mat-like thing is detected to estimate the load of the passenger sitting on the seat.
[0003]
[Problems to be solved by the invention]
However, in the case where a strain sensor is provided in the vehicle body mounting portion or seat rail portion of the seat, a high-performance sensor is required because the strain sensor detects minute strain as described above. In addition, the detection circuit is complicated and expensive. In addition, in the case where the load distribution is detected by a mat-like object, the mat is large and expensive, and when other parts (such as a heater) are incorporated in the seat cushion, interference with the parts becomes a problem. Thus, not only is the degree of freedom in designing the seat narrowed, but there are problems that the load estimation program becomes complicated if a large number of load distribution detection points are arranged to increase the load estimation accuracy.
[0004]
In both the load detection structures as described above, there is a problem that it is difficult to discriminate between children including child seats and small people. For this determination, some seat belts are provided with a tension sensor in order to detect the magnitude of the seat belt tension when the child seat is attached. However, since a tension sensor is added to the seat belt, there is a problem in that the entire system becomes expensive.
[0005]
[Means for Solving the Problems]
In order to solve such a problem and realize the determination of the size and sitting state of an occupant seated on a seat with a simple structure, in the present invention, a load receiving portion that receives a seat load due to the seating. A plurality of springs interposed between the seat frame and the load receiving portion to support the suspension in a state suspended from the seat frame; a plurality of displacement sensor provided for each one corresponding to the respective portions of the plurality of springs in order to detect a load at an elongation of the spring, the total value and the front and rear left and right load value detected by the plurality of displacement sensors An occupant discriminating means for discriminating the magnitude of the load and the seating state of the occupant seated by obtaining each load difference.
[0006]
According to this, it is possible to detect the load by the extension of the spring that supports the load receiving portion. Distribution can be easily determined. Based on the discrimination results, it is possible to discriminate between adults, small people, children, and the like.
[0007]
In particular, the detection value before Symbol displacement sensor, by obtaining corrected as balance of the plurality of displacement sensors when no load is constant, can be accurately determined.
[0008]
Alternatively, a plurality of intervening members between the seat frame and the load receiving portion to support at least the front, rear, left and right portions of the load receiving portion that receives the seat load due to the seating in a suspended state with respect to the seat frame. of each elongation of the spring is detected by a corresponding plurality of displacement sensors, the Rutotomoni find the total value of the load of each part, it is compared with the respective upper limit value corresponding to the load difference between the longitudinal and lateral, the total It is good to determine whether the child is seated when it is determined from the value whether the person is an adult or not, and at least it is determined that there is no bias in the right and left of the seat from the respective load differences . In particular, the case where it is determined from the load difference is skewed to the left and right of the seat, or is not biased to the left and right of the seat rear portion of the discriminated and the seat and is biased before and after the sheet If it is determined that the load is large, it may be determined that the seating is abnormal. In addition, the detection value of the displacement sensor can be determined with high accuracy by obtaining the detection value so that the balance of the plurality of displacement sensors is constant when there is no load .
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail based on specific examples shown in the accompanying drawings.
[0010]
FIG. 1 is a diagram showing an overall configuration of an occupant discrimination sheet to which the present invention is applied. As shown in the drawing, for example, a net-like load receiving portion 2 that receives a load applied to the seating portion 1a when a passenger is seated is disposed under the seat seating portion 1a of the front seat 1 of the automobile. A seat frame 3 formed in a substantially rectangular frame shape is provided below the seat 1, and the seat frame 3 is fixed on the floor panel of the vehicle body.
[0011]
The load receiving portion 2 is supported in a state of being elastically suspended from the seat frame 3 via a plurality of coil springs 4a, 4b, 4c, 4d, 4e, and 4f. In the illustrated example, as shown in FIG. 2, coil springs 4 a to 4 f are arranged one by one at the front, middle, and rear portions of the left and right side portions of the load receiving portion 2. In addition, although a coil spring is suitable, it is not limited to a coil spring, The spring of another form may be sufficient. The left and right front and rear coil springs 4a, 4b, 4c and 4d are provided with displacement sensors 5a, 5b, 5c and 5d for detecting the extension of the springs. As the displacement sensors 5a to 5d, there is a capacitance type as shown in FIG. 3, for example (for example, JP-A-2001-281075). In addition, there is a technique using a resistance change (for example, Japanese Patent Application No. 20001-232823).
[0012]
The displacement sensor of FIG. 3 includes a small-diameter bottomed cylindrical body 7 that can be displaced integrally with one coil end of the coil spring 6 and that surrounds the spring coaxially, and the other coil end of the coil spring 6. And a large-diameter bottomed cylindrical body 8 that coaxially surrounds the small-diameter bottomed cylindrical body 7. An inner electrode 9 a is provided on the outer peripheral surface of the small-diameter bottomed cylindrical body 7, and an outer electrode 9 b is provided on the inner peripheral surface of the large-diameter bottomed cylindrical body 8. When tension is applied to the coil spring 6 as shown by the arrows in the figure to cause elongation, the capacitance between the electrodes 9a and 9b changes, and the change is detected voltage (V1, V2, V3, V4). (ΔV1, ΔV2, ΔV3, ΔV4).
[0013]
In this way, the load acting on the seat 1 can be detected by the displacement sensors 5a to 5d. In addition, even if the characteristics of the coil springs 4a to 4d and the displacement sensors 5a to 5d are different from each other, they can be adjusted by calibrating them while attached to the seat 1, and it is necessary to strictly use the same characteristics. There is no. Further, since the coil springs 4a to 4d and the displacement sensors 5a to 5d are disposed on the outer peripheral portion of the load receiving portion 2 corresponding to the seat seating portion 1a, for example, even when a heater is incorporated in the seat, they are obstructive. In other words, there is no inconvenience that the application range of the sheet having this structure is narrowed.
[0014]
Next, load detection signal processing is shown in the block diagram of FIG. As shown in the figure, each of the displacement sensors 5a to 5d is connected to a sensor input / output circuit 11a in the occupant discrimination ECU 11. In the occupant discrimination ECU 11, an A / D conversion circuit 11b for digitally converting an analog signal from the sensor input / output circuit 11a, a microcomputer 11c for executing control, a microcomputer 11c, and an external airbag ECU 12 are provided. A vehicle communication circuit 11d provided between the two, a memory 11e composed of an EEPROM for storing, for example, non-sitting data and individual seat data, and a power supply unit 11f. It has been. The microcomputer 11c and each circuit exchange signals as indicated by arrows in the figure.
[0015]
As a result, as will be described later, detection voltages output from the displacement sensors 5a to 5d are input to the occupant discrimination ECU 11, and the occupant discrimination ECU 11 processes each detection voltage to determine the occupant's load and seating state. It can be set as the system which performs discrimination | determination and transmits the result to ECU12 for airbags from ECU11 for passenger | crew discrimination | determination. In the illustrated example, four displacement sensors are provided. However, the number of displacement sensors may be more than that, and the number of displacement sensors is not limited to four.
[0016]
Next, the load detection procedure by the displacement sensors 5a to 5d will be described. Note that the initial values (V1 ₀ , V2 ₀ , V3 ₀ , V4 ₀ ) of the displacement sensors 5a to 5d in a non-sitting state in which no occupant is seated are stored in advance when, for example, the door is opened before shipment or before engine start Store in the memory 11e.
[0017]
For example, when the state of the coil springs 4a and 4b when the occupant is not seated is as shown in FIG. 5A, when the occupant is seated on the seat, the load is shown in FIG. 5B. The coil springs 4a and 4b extend. Assuming that the extension of each coil spring is Δx _n , the amount of change in spring load when seated from a non-sitting state is ΔF _n , and the spring constant is k,
ΔF _n = k × Δx _n
It becomes. The subscript n can be a number from 1 to 4 in the case of detection at four locations as in the illustrated example, and varies depending on the displacement sensor.
[0018]
Further, the extension (Δx _n ) of each coil spring 4a to 4d at each part (front, rear, left and right of the seat) is detected by each displacement sensor, and each detection voltage (V1, V2, V3, V4) corresponding to the extension is output. Is done. The detected voltage is A / D converted in the occupant discrimination ECU 11 as described above, and the displacement voltage ΔVN corresponding to the elongation is obtained by the microcomputer 11 c in the occupant discrimination ECU 11.
ΔVN = VN−VN ₀ (1)
(N = 1, 2, 3, 4). Data is analyzed based on these displacement voltages.
[0019]
At this time, it is preferable to correct data for the outputs (V1, V2, V3, V4) of the displacement sensors 5a to 5d in order to eliminate differences in sheet types and production variations. Depending on the seat, the detection values (LH, RH, F, B) of the left side load, right side load, front side load, and rear side load in seating may not be detected with the same sensitivity. For example, the left side load detection value LH is large. There are some that tend to become large, and some that the front load detection value F tends to become large. Such a phenomenon also occurs due to individual differences depending on the displacement sensor, the seat, and their attachment state.
[0020]
Therefore, for example, a coefficient may be applied to each output so that the balance of each output (V1, V2, V3, V4) is constant when there is no load. For example, if the correction value of VN in the above equation (1) is V′N,
V′N = A (VN) (2)
It becomes. Also,
V′N = A (VN) ^x (3)
It is also good. The coefficient A and the power index x may be obtained by experiments or the like.
[0021]
By correcting in this way, it is possible to eliminate detection errors due to differences in the types of sheets and production variations. In addition, it is possible to eliminate detection errors due to differences in individual differences depending on the displacement sensor, the seat, and their attachment state. Therefore, it is possible to easily obtain a high-accuracy detection value without increasing the precision of manufacturing the sheet, the displacement sensor and the mounting method, and to reduce the cost of the apparatus. Versatile because it only needs to be set.
[0022]
By data analysis, it is possible to perform occupant discrimination consisting of five states: adults, small people, children (including child seats), luggage, unsitting, and abnormal seating. In addition, these five states are examples, and are not limited to this. An example of the discrimination control is shown below based on the flow shown in FIG.
[0023]
First, in step ST1, sensor data is read, and in the next step ST2, a total value S (= ΔV1 + ΔV2 + ΔV3 + ΔV4) of detection voltages of respective displacements is obtained. In the illustrated example, since the load receiving portion 2 is supported by six coil springs 4a to 4f, the total value S can be handled as a proportional size although it is not the actual weight of the occupant. In the control program, the voltage value can be used as it is, but in the following description, each value is expressed as a load unless otherwise specified.
[0024]
In step ST3, it is determined whether or not the total value S is equal to or greater than a threshold value a for determining an adult. If it is determined that the total value S is greater than or equal to the threshold value a, the process proceeds to step ST4, where it is assumed that an adult is seated, and the information is transmitted to the airbag ECU, and this routine is terminated. When it is determined that the total value S is smaller than the threshold value a, the process proceeds to step ST5.
[0025]
In step ST5, it is determined whether or not the total value S is equal to or greater than a threshold value b for determining a small person. If it is determined that the total value S is smaller than the threshold value b, the process proceeds to step ST6. In step ST6, it is further determined whether or not the total value S is greater than or equal to a threshold value c for determining a package or the like. In addition, the magnitude relationship of each threshold value a * b * c is a>b> c.
[0026]
If it is determined in step ST6 that the total value S is equal to or greater than the threshold value c, the process proceeds to step ST7, where it is determined that a baggage or the like is loaded, and the information is transmitted to the airbag ECU. Exit. If it is determined that the total value S is smaller than the threshold value c, the process proceeds to step ST8, where it is determined that the seat is not seated and nothing is placed on the seat, and the information is transmitted to the airbag ECU. Then, this routine ends.
[0027]
If it is determined in step ST5 that the total value S is greater than or equal to the threshold value b, the process proceeds to step ST9 shown in FIG. In step ST9, the absolute value (| LH−RH |) of the left / right difference of the load detection value is obtained, and it is determined whether or not the left / right difference (| LH−RH |) is equal to or greater than the upper limit value d. In the illustrated example, the left load LH is ΔV2 + ΔV4, and the right load RH is ΔV1 + ΔV3.
[0028]
Note that the case where the left / right difference (| LH−RH |) is equal to or greater than the upper limit d is a case where the difference between the left and right load distributions is too large. In such a case, there is a possibility that the effect as designed may not be obtained in the deployment of the airbag. Therefore, the process proceeds to step ST10, where it is determined that the seating is abnormal, and the information is transmitted to, for example, the airbag ECU. This routine is terminated. In this case, a seating abnormality display and warning can be performed by the airbag ECU.
[0029]
If it is determined in step ST9 that the left / right difference (| LH−RH |) does not exceed the upper limit d, the process proceeds to step ST11. If the process proceeds to step ST11, there is no bias in the left-right difference in the load distribution. Therefore, in step ST11, for example, the right-side load RH is compared with the threshold value e, and it is first determined whether or not the child is a child. To do. That is, if it is determined in step ST11 that the right load RH does not exceed the threshold value e, the process proceeds to step ST12, where it is determined that the child is seated, and the information is transmitted to the airbag ECU. End the routine. In this case, the airbag ECU can perform soft deployment control for a child when the airbag of the corresponding seat is deployed, or can perform non-deployment.
[0030]
If it is determined in step ST11 that the right load RH is greater than or equal to the threshold value e, the process proceeds to step ST13, where the difference between the rear load B (= ΔV3 + ΔV4) and the front load F (= ΔV1 + ΔV2) ( FB |), and if the difference (| F | B |) is less than the threshold value h, the process proceeds to step ST14. In the case of proceeding to step ST14, for example, a case where the user is seated deeply is considered. In order to determine the load in such a case more accurately, the rear load B is compared with the threshold value f for determining the child. To do. If it is determined in step ST14 that the rear load B is greater than or equal to the threshold value f, the process proceeds to step ST15, where it is determined that the seating is abnormal or cannot be determined, and the information is transmitted to the airbag ECU. finish. In this case, the airbag ECU can display a warning or alarm for abnormal seating. The case of proceeding to step ST15 is a case where the load distribution in the left and right portions is small but the load on the rear side is large. For example, a case where a child stands is conceivable.
[0031]
If it is determined in step ST14 that the rear load B is smaller than the front load F, the process proceeds to step ST16. In this case, since the total value S is small and the lateral deviation is small, and the load on the rear portion of the seat is smaller than the threshold value f for determining the child, for example, the child is seated shallowly. There may be cases. Accordingly, it is determined in step ST16 that the child is in a seated state, the information is transmitted to the airbag ECU, and this routine is terminated. In this case, the airbag ECU can perform soft deployment control for the child when deploying the airbag of the corresponding seat.
[0032]
If it is determined in step ST13 that the difference (| F−B |) is greater than or equal to the threshold value h, the process proceeds to step ST17. In step ST17, for example, a case where the user sits shallowly is considered. In order to more accurately determine the load in such a case, the rear load B is compared with the threshold value g. If it is determined in step ST17 that the rear load B does not exceed the threshold value g for determining a small person, it is considered that the child is seated shallowly, and the process proceeds to step ST16, where the above-described operation is performed. Process.
[0033]
If it is determined in step ST17 that the rear load B is greater than or equal to the threshold value g, the process proceeds to step ST18. In this case, since the total value S is small and the lateral deviation is small, and the load on the rear side of the seat is equal to or greater than the threshold value g for identifying a small person, the small person is determined in step ST18. Is determined to be in the seated state, the information is transmitted to the airbag ECU, and this routine is terminated. In this case, the airbag ECU can perform deployment control for a small person when deploying the airbag of the corresponding seat.
[0034]
The displacement sensor is not limited to the example shown in the drawings, and may be other types, for example, a resistance change type, a type using a Hall element, a differential transformer, or electromagnetic induction. In any case, a sensor that can convert the elongation (displacement) of the spring into a voltage can be used.
[0035]
Further, although the displacement sensor is configured to detect linear displacement, it can be configured to detect rotational displacement. An example is shown in FIG. In the figure, rotational displacement sensors 13a, 13b, 13c, and 13d are disposed in the vicinity of the left and right front and rear coil springs 4a, 4b, 4c, and 4d disposed in the same manner as in the illustrated example. ing. As shown in FIGS. 9 and 10, the rotational displacement sensors 13 a to 13 d include a sensor main body 14 fixed to the side wall portion of the seat frame 3, and a rotary pulley 15 rotatably supported by the sensor main body 14. It consists of. A wire 16 is wound around the rotating pulley 15, and the tip of the wire 16 is connected to the load receiving portion 2. The rotational displacement sensors 13a to 13d have a built-in return spring connected to the rotary pulley 15, so that the wire 16 is always wound up elastically.
[0036]
Next, with reference to FIG. 10 similar to FIG. 5, a procedure for detecting displacement by the rotational displacement sensors 13a to 13d will be described. FIG. 10A shows a state in which no occupant is seated, and the length of the coil spring 4b in this case is X0. When seated, the coil spring 4b extends as shown in FIG. 10B, and its length is X1. In addition, although it shows about the coil spring 4b and the rotational displacement sensor 13b corresponding to it, it is the same also in another combination, The description is abbreviate | omitted.
[0037]
The elongation ΔX of the coil spring 4b due to the seating is (X1-X0). At this time, since the wire 16 is pulled out according to the elongation ΔX, the rotary pulley 15 of the rotational displacement sensor 13b rotates accordingly. Here, if the radius of the rotating pulley 15 (the radius of the portion around which the wire 16 is wound) is r, the rotation angle Δθ is
Δθ = (ΔX × 360) / 2πr (4)
It is represented by A sensor output corresponding to the rotation angle Δθ is obtained, and in this case, the detection voltage V2. The subsequent processing is the same as that described for the linear displacement sensor.
[0038]
【The invention's effect】
As described above, according to the present invention, without using a seat belt tension sensor or the like, the occupant's load is received using a spring, and the displacement of the spring with respect to the load is measured using a plurality of displacement sensors. Therefore, by analyzing the detected voltage with a microcomputer, the magnitude of the occupant's load and the seating state can be detected. By using it for the bag control, it is possible to control the deployment of the airbag according to the occupant. Since the detection structure for that purpose can be realized with a simple structure using the spring as described above, the overall cost can be reduced.
[0039]
In particular, if the displacement sensor detects linear displacement or rotational displacement, the spring and the displacement sensor can have a simple configuration. In addition, the detection value of the displacement sensor can be determined with high accuracy by correcting it with a coefficient obtained experimentally in advance.
[0040]
Also, by analyzing the total value of the detection voltages of multiple displacement sensors obtained by occupant load input in the discrimination algorithm and the load distribution due to each detection voltage, for example, when the total value is smaller than an adult and the seat front load is large It is possible to discriminate that a small person is seated, and it is also possible to discriminate a small person who has been difficult to discriminate until now.
[Brief description of the drawings]
FIG. 1 is a diagram showing an overall configuration of an occupant discrimination sheet to which the present invention is applied.
FIG. 2 is a plan view showing an arrangement of displacement sensors.
FIG. 3 is a longitudinal sectional view showing an example of a displacement sensor.
FIG. 4 is a block diagram of an occupant discrimination ECU.
5A is a schematic front view showing a state of a coil spring and a displacement sensor when not seated, and FIG. 5B is a diagram showing a state when seated.
FIG. 6 is a diagram showing a control flow for occupant discrimination.
FIG. 7 is a diagram showing a control flow for occupant discrimination.
FIG. 8 is a view corresponding to FIG. 2 showing an example using a rotational displacement sensor.
FIG. 9 is an enlarged perspective view of a rotational displacement sensor.
10A is a schematic front view showing a state of a coil spring and a rotational displacement sensor when not seated, and FIG. 10B is a diagram showing a state when seated.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Seat 2 Load receiving part 3 Seat frame 4a-4f Spring 5a-5d Displacement sensor 11 ECU for passenger determination
11a Sensor input / output circuit, 11b A / D conversion circuit 11c Microcomputer, 11d Vehicle communication circuit 11e Memory 12 ECU for airbag
13a, 13b, 13c, 13d Each rotational displacement sensor 14 Sensor body 15 Rotating pulley 16 Wire

Claims (5)

A plurality of springs interposed between the load receiving portion for receiving a load of the sheet by the seating with the seat frame and the load bearing portion so as to support in a state of suspended relative to the seat frame, of the load receiving portion a plurality of displacement sensor provided for each one corresponding to the respective portions of the plurality of springs in order to detect a load at the time of sitting at each part of the left and right at least before and after elongation of the spring, the detection of the plurality of displacement sensors An occupant discrimination sheet having occupant discriminating means for discriminating a magnitude and a seating state of a seated occupant by obtaining a total load value and a load difference between the front, rear, left and right by values. The occupant determination sheet according to claim 1, wherein the detection value of the displacement sensor is obtained by correcting so that the balance of the plurality of displacement sensors is constant when there is no load . A plurality of springs interposed between the seat frame and the load receiving portion to support at least each of the front, rear, left and right portions of the load receiving portion that receives the seat load due to the seating in a suspended state with respect to the seat frame , Each of the elongation is detected by a plurality of corresponding displacement sensors ,
Rutotomoni find the total value of the load of each portion is compared with the respective upper limit value corresponding to the load difference between the longitudinal and lateral,
It is determined from the total value whether or not it is an adult, and it is determined that the child is seated when it is determined that it is not at least the adult and it is determined that there is no bias in the right and left of the seat from the respective load differences. An occupant discrimination control method for an occupant discrimination sheet. When it is determined from the load differences that there is a deviation in the left and right of the sheet, or it is determined that there is no deviation in the right and left of the sheet but there is a deviation in the front and rear of the sheet, and the load on the rear portion of the sheet is The occupant discrimination control method for an occupant discrimination seat according to claim 3, wherein if it is determined to be large, it is discriminated that the seating is abnormal . 5. The occupant discrimination control of the occupant discrimination seat according to claim 3, wherein the detection value of the displacement sensor is obtained by correcting so that the balance of the plurality of displacement sensors becomes constant when there is no load. Method.

Images