JP2000025559A - Occupant detection system, and occupant detecting method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an occupant detection system which is capable of correctly recognizing the occupant seated in a seat without being much affected by the seating posture of the occupant, and appropriately controlling an air bag device based on the result of judgment. SOLUTION: An occupant detection system is provided with a plurality of strip-like antenna electrodes arranged on a back part of a seat separated from each other with approximately constant intervals in a vertical direction, an electric field generating means 11 to generate the weak electric field around the antenna electrodes, a current detection circuit 15 to detect the running current based on the electric field generated around a specified antenna electrode, a control circuit 10 which detects a head part based on the signal data acquired from the current detection circuit, and judges whether or not the occupant is a child based on the data from which the data on the head part is eliminated when the head part is detected, and an air bag device 30 having the function to develop the air bag in the collision, and the air bag of the air bag device is set to either the developing condition or the non-developing condition based on the result of judgment of the control circuit.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an occupant detection system and an occupant detection method, and more particularly to a state in which an airbag of an airbag device can be deployed according to the occupant's seating status in a passenger seat of an automobile equipped with the airbag device. Also, the present invention relates to an occupant detection system and an occupant detection method that can be set to a state where deployment is impossible.

[0002]

2. Description of the Related Art Generally, an airbag device is a device for reducing the impact received by an occupant at the time of a collision of an automobile.
It has become indispensable to the safety of automobiles, and has recently been installed not only in the driver's seat but also in the passenger seat.

As shown in FIG. 14, for example, this airbag device has a self-service sensor SS1 and a squib SQ.
1, a squib circuit on the driver's side comprising a series circuit of semiconductor switching elements SW1 such as field effect transistors, and a semiconductor switching element SW such as a safing sensor SS2, a squib SQ2 and a field effect transistor.
2, a squib circuit on the passenger seat side, an electronic acceleration sensor (collision detection sensor) GS, and an electronic acceleration sensor G
A control circuit CC having a function of determining the presence or absence of a collision based on the output signal of S and supplying a signal to the gates of the semiconductor switching elements SW1 and SW2.

According to this airbag device, when an automobile collides for some reason, the switching contacts of the safety sensors SS1 and SS2 are closed in response to a relatively small acceleration, and the safety sensors SS1 and SS2 are closed. The squib circuit on the passenger seat side becomes operable. When the control circuit CC determines that the vehicle has definitely collided based on the signal from the electronic acceleration sensor GS, a signal is supplied to the gates of the semiconductor switching elements SW1 and SW2, and the switching elements SW1 and SW2 are turned on. Becomes ON state. As a result, current flows through each squib circuit,
Due to the heat generated by the squibs SQ1 and SQ2, the airbags on the driver's seat side and the passenger's seat side are deployed, and the occupant is protected from the impact due to the collision.

[0005] By the way, since this airbag device is configured so that the airbag is deployed in the event of an automobile collision, regardless of whether or not the occupant is seated on the seat, for example, an adult occupant is seated in the passenger seat. When a passenger is seated, the above-mentioned effect of protecting the occupant can be expected in the event of a collision. Is concerned. Therefore, it is recommended that the airbag should not be deployed even if the vehicle collides.

[0006]

Therefore, conventionally, in order to cope with such a problem, an airbag device as shown in FIG. 15 has been proposed. In this airbag device, a sensor SD for detecting whether or not an occupant is seated in a passenger seat is installed, and a control circuit CC determines the seating status of the occupant in the passenger seat based on a detection signal of the sensor SD. When an automobile collides, the airbag is set to one of a deployable state and an undeployable state. In particular, as the sensor SD, a sensor using a weight sensor for measuring the weight, and a sensor SD that determines whether the child is an adult or a child by image processing by photographing an occupant sitting on a sheet with a camera have been proposed. I have.

[0007] According to the former method, it is possible to roughly determine whether the occupant is an adult or a child, and based on the result, the airbag is set to one of a deployable state and an undeployable state. Although it is possible to avoid an unexpected situation at the time of a collision of a car, there is a problem that accuracy is lacking because the weight varies greatly among individuals and even a child may be heavier than an adult.

Further, according to the latter method, although the occupant's seating state and the judgment of whether the occupant is an adult or a child can be made quite accurately, image data taken by a camera is image-processed and various patterns are obtained. The processing unit becomes complicated and expensive because it has to make a comparison judgment with
When the occupant is a child, the position of the head is unstable, so that not only the pattern recognition is complicated, but also the processing is further complicated.

Therefore, an object of the present invention is to identify an occupant seated on a sheet accurately without being influenced by the occupant's seating posture, and based on the determination result. An object of the present invention is to provide an occupant detection system and an occupant detection method capable of appropriately controlling a bag device.

[0010]

SUMMARY OF THE INVENTION Accordingly, in order to achieve the above-mentioned object, the present invention provides a plurality of strip-shaped antenna electrodes which are arranged at substantially regular intervals in a vertical direction on a backrest of a sheet. And, an electric field generating means for generating a weak electric field around the antenna electrode, and among the plurality of antenna electrodes, generating a weak electric field around a specific antenna electrode,
A current detection circuit for detecting a current flowing based on the electric field; and a head based on signal data taken from the current detection circuit. If the head is detected, data on the head is detected. A control circuit for determining whether or not the occupant is a child based on the removed signal data.

In a second aspect of the present invention, there are provided a plurality of strip-shaped antenna electrodes which are vertically spaced apart from each other at substantially constant intervals on a backrest of a sheet, and a weak electric field is applied around the antenna electrodes. An electric field generating means for generating, a current detecting circuit for generating a weak electric field around a specific antenna electrode among a plurality of antenna electrodes, and detecting a current flowing based on the electric field; The head is detected based on the received signal data, and when the head is detected,
A control circuit for determining whether or not the occupant is a child based on signal data from which data relating to the head has been removed; and an airbag device having a function of deploying the airbag based on a collision. A data based on the determination result of the control circuit.
Transmitting the airbag to the airbag device, and setting the airbag of the airbag device to one of an expandable state and an undeployable state.

According to a third aspect of the present invention, the control circuit determines a ratio of each signal data to a total of the signal data taken in from the current detection circuit and applies the ratio to the adjacent antenna electrode. The head is detected by comparing the ratio data and the threshold data with respect to the head stored in advance, and when the head is detected, the data on the head is detected. By calculating the ratio of the individual signal data to the sum of the signal data from which the occupant has been removed and comparing the ratio data with a previously stored threshold value for identification of the occupant, the occupant can be identified as a child. It is controlled to determine whether or not there is.

According to a fourth aspect of the present invention, a weak electric field is selectively generated around a plurality of band-shaped antenna electrodes arranged at substantially constant intervals in a vertical direction on a backrest of a sheet. The head is detected based on the signal data relating to the current flowing based on the electric field, and if the head is detected, the occupant is determined based on the signal data obtained by removing the data relating to the head. Or not.

Further, according to a fifth aspect of the present invention, a weak electric field is selectively applied to the periphery of a plurality of band-shaped antenna electrodes which are arranged at substantially constant intervals in the vertical direction on the backrest of the sheet. The ratio of individual signal data to the sum of signal data relating to a current flowing based on this electric field is determined, and a head is detected based on the ratio data. The ratio of the individual signal data to the sum of the signal data from which the data relating to the head has been removed is determined, and this ratio data is compared with a previously stored threshold value for identification of the occupant. Accordingly, it is determined whether or not the occupant is a child, and based on the determination result, the airbag of the airbag device is set to one of a deployable state and an undeployable state. .

[0015]

Next, the basic principle of the present invention will be described with reference to FIG. An occupant detection system and an occupant detection method according to the present invention basically provide a weak electric field (Electric F) generated on an antenna electrode disposed on a sheet.
ield). First, FIG.
As shown in the figure, by applying a high-frequency low voltage from the oscillation circuit OSC to the antenna electrode E1,
1 generates a weak electric field around the antenna electrode E1.
The current I flows on the side of. In this state, as shown in FIG. 3B, the object O is located near the antenna electrode E1.
When B is present, the electric field is disturbed and the antenna electrode E
A current I ₁ different from the current I flows on the side 1.

Therefore, depending on whether the object OB is on the vehicle seat or not, the antenna electrode E
A change occurs in the current flowing to the side 1 and by utilizing this phenomenon, it is possible to detect whether or not the occupant is seated on the seat and to determine whether the occupant is a child or an adult. And so on. In particular, by increasing the number of antenna electrodes, it is possible to obtain a lot of information on the object (occupant) on the sheet, and it is possible to more accurately detect the occupant's seating state on the sheet.

Next, an embodiment of an occupant detection system according to the present invention utilizing this principle will be described with reference to FIGS. The same parts as those of the conventional example shown in FIGS. 14 and 15 are denoted by the same reference numerals, and the detailed description thereof will be omitted. 2 and 3 show a seat of a passenger seat (driver's seat) according to the present invention. The seat 1 mainly includes a seating portion 1a.
And a backrest 1b. Seating part 1a
Is composed of a sheet frame 3 fixed to a base 2 which can be slid forward and backward, a cushion material disposed on the upper portion of the sheet frame 3, and an exterior material covering the cushion material. The backrest 1b is configured by, for example, arranging a cushion material on the front side of a sheet frame and covering the cushion material with an exterior material. In particular, a plurality of strip-shaped antenna electrodes 4 (4a, 4a) are provided on the backrest 1b.
4f) are arranged so as to be separated from each other in a substantially horizontal state in the vertical direction, and to be located over a wide range in the width direction of the backrest portion. In addition, the antenna electrode 4 can be arranged outside or outside the exterior material, or can be provided on the exterior material itself. Further, a control unit 10 to be described later is arranged in or near the sheet frame 3.

The antenna electrode 4 is made of, for example, a conductive cloth.
, The conductive paint is applied to the cloth surface, or a metal plate is arranged. In particular, as shown in FIG. 3, for example, the antenna electrode 4 is formed on one surface of a base member 5 made of an insulating member in the form of a band of the same size (for example, width 30 mm, length 280 mm)
.. 4f are vertically spaced apart from each other by a predetermined distance (for example, 10 mm).
It is desirable to constitute by integrating, and it is arranged inside the exterior material of the backrest 1b. In particular, the lead wires 6 (6a, 6a, 4a, 4b,.
6b) are independently derived, and connectors (or terminals) 19a, 1 of the control unit 10 described later are provided.
9b... 19f.

A control unit 10 is arranged in the sheet frame 3 of the sheet 1 or in the vicinity thereof. The control unit 10 has a frequency of about 100 KHz, for example, as shown in FIG. Electric field generating means (for example, an oscillation circuit) 11 for generating a weak electric field around the antenna electrode 4 by a high frequency low voltage of about 5 to 12 V, and an amplitude for controlling a voltage amplitude of a transmission signal from the oscillation circuit 11 to be substantially constant. A control circuit 12, a current detection circuit 15 for detecting a transmission current of the transmission signal, an AC-DC conversion circuit 16 for converting an output signal of the current detection circuit 15 into a direct current,
An amplifier 17 for amplifying an output signal of the conversion circuit 16 and an antenna electrode 4a connected to the current detection circuit 15 and having a plurality of switching means 18a, 18b,.
.. 1 connected to switching means 18a to 18f of switching circuit 18 and switching means 18a to 18f of switching circuit 18 and arranged in the housing of the control unit.
9f, a control circuit 20 including an MPU, etc., a connector 21 arranged in the housing and connected to a battery power source (not shown), and a power supply circuit 22 connected between the connector 21 and the control circuit 20 and the like. ing. The control circuit 20 of the control unit 10 is connected to, for example, an airbag device 30 having a configuration shown in FIG. Incidentally, the selective switching of the switching means 18a to 18f in the switching circuit 18 is performed based on a signal from the control circuit 20.

In the control unit 10, the amplitude control circuit 12 includes, for example, an amplitude variable circuit 13 for varying the voltage amplitude of the transmission signal and an amplitude detection circuit 14 for detecting the voltage amplitude of the transmission signal. The variable amplitude circuit 13 includes, for example, a programmable gain amplifier (PG
A), the amplitude detection circuit 14 includes a voltage amplitude detection unit 14a such as an operational amplifier, and an AC-DC conversion circuit 14b that converts an output signal of the detection unit 14a into a direct current. And an amplifier 14c for amplifying the output signal of the AC-DC conversion circuit 14b. The output signal of the amplifier 14c is supplied to the control circuit 20, and the variable amplitude signal for the variable amplitude section 13a is output from the control circuit 20.

In the control unit 10, the current detection circuit 15 includes, for example, an impedance element such as a resistor 15a connected in series to a circuit (transmission signal system), and a differential amplifier for amplifying a terminal voltage of the resistor 15a. Amplifier 1 such as
5b. The output side of the current detection circuit 15 is connected to a control circuit 20 via an AC-DC conversion circuit 16 and an amplifier 17. And the current detection circuit 1
5, the output side of the resistor 15a is connected to the connectors 19a to 19f via the switching circuit 18.

The occupant detection system thus configured operates as follows. First, when a high-frequency low voltage is transmitted from the oscillation circuit 11, the voltage amplitude thereof is detected by the detection unit 14a of the amplitude detection circuit 14, and the detection signal is A
The direct current is converted by the C-DC conversion circuit 14b to the
The signal is amplified at 4c and input to the control circuit 20. The control circuit 20 determines whether or not the detected voltage amplitude has a predetermined amplitude value, and outputs an amplitude variable signal for correcting the detected voltage amplitude to the predetermined voltage amplitude to the amplitude variable section 13a. Thereby, the voltage amplitude of the transmission signal is corrected to a predetermined amplitude,
Thereafter, the amplitude is controlled to be constant by the cooperative operation of the amplitude variable circuit 13 and the amplitude detection circuit 14.

The transmission signal having a constant voltage amplitude is supplied to the antenna electrode 4 via the current detection circuit 15, the switching circuit 18, and the connectors 19a to 19f. As a result, a weak electric field is generated around the antenna electrode 4. Is done. At this time, the switching circuit 18 is controlled to open and close by a signal from the control circuit 20. At first, only the switching means 18a is closed, then only the switching means 18b is closed, and then only the switching means 18c is closed. The switching is controlled to be selectively performed such that only the specific switching means is sequentially closed and the other switching means are opened at the same time. Therefore, when the specific switching means (18a to 18f) is closed, the transmission signal whose voltage amplitude is fixed is transmitted to the current detection circuit 15, the specific switching means (18a to 18f), and the specific connector (1).
9a to 19f) through specific antenna electrodes (4a to 4f).
f) so that a particular antenna electrode (4a
4f), a weak electric field is generated, and currents of different levels flow according to the sitting posture of the occupant sitting on the seat 1. That is, a current flows according to the difference in the contact area (opposed area) between the occupant's back, shoulder, neck, and head. This current is detected by the current detection circuit 15 and A
The DC signal is converted by the C-DC conversion circuit 16 into an
And is input to the control circuit 20 one after another.

The control circuit 20 has a threshold value (threshold data) THe for discriminating whether or not the seat 1 is empty (Empty) and a discrimination of the head of the occupant. A threshold value (threshold value data) TH1 and a threshold value (threshold value data) relating to occupant identification (child / adult distinction)
D) TH2, TH3, and TH4 are stored (stored).

That is, with respect to the threshold value THe regarding whether or not the seat is vacant, when a child or adult occupant is seated on the sheet, the plurality of antenna electrodes 4 (4a to 4a) are set.
Since the sum S of the output signals based on the current flowing through f) becomes equal to or more than a certain value, the output signal is set based on this sum. The threshold value THe is specifically set to, for example, 20. If the actual total S is larger than 20, it is determined that the occupant is seated, and if the actual total S is smaller than 20, it is determined that the seat is vacant. .

Threshold TH1 for identification of the occupant's head
With respect to the current, the level of the current flowing through each of the antenna electrodes 4a to 4f differs due to the difference in the contact area (opposed area) with the seat 1 on the head, neck, shoulder, and back of the occupant. The setting is made using the characteristic difference between children and adults. That is, in the case of a child occupant, as shown in FIG. 6 (a), the level of the current flowing through the antenna electrodes 4c to 4f corresponding to the part below the shoulder is highest at the part below the shoulder, and then the head ( Antenna electrode 4a), the neck (antenna electrode 4b) is at the lowest level, and in the case of an adult occupant, as shown in FIG.
The antenna electrode corresponding to the head does not exist, and the level of the current flowing through the antenna electrodes 4a to 4f corresponding to the part at the portion below the neck becomes higher from the neck to the shoulder and back to the lower portion. Therefore, the output signals of the vertically adjacent antenna electrodes are compared with each other, and it is determined that the head is located next to (the upper side of) the lowest level. Therefore, the threshold value TH1 is set as a reference for the level. . In particular, the current flowing through the antenna electrodes depends on the thickness, body shape, etc. of the occupant's clothing. To mitigate the effects, signal data relating to the current flowing through each antenna electrode is shown in FIG. As shown in FIG. 7B and FIG. 7B, the output signal is converted into the ratio to the total sum S of the output signals.
The threshold value TH1 is specifically set to, for example, 0.13. The antenna electrode portion that outputs smaller signal data is the neck, and the upper antenna electrode portion is the head. Is determined.

The threshold values TH2, TH3 and TH4 relating to occupant identification (discrimination between children and adults) are shown in FIG.
As shown in (b) and FIG. 7 (b), the setting is made using the fact that current patterns flowing through a plurality of antenna electrodes are different between children and adults. That is, in the case of a child SP,
The output signals (ratio data) of the antenna electrodes 4a to 4d corresponding to the upper part from the head to the back are small, and the output signals (ratio data) of the antenna electrodes 4e to 4f corresponding to the middle part of the back and lower.
Is large, and in the case of the adult P, an output signal (ratio data) that is partially prominent as in the case of a child is not seen. Therefore, if the output signals of the antenna electrodes 4a to 4d are smaller than a certain value and any of the output signals of the antenna electrodes 4e to 4f is larger than a certain value, the occupant can be determined to be a child and the condition is not satisfied. above,
If all output signals of the antenna electrodes 4a to 4f are smaller than a certain value, it is determined that the occupant is an adult (or GRAY). These constant values are threshold values TH2 and T, respectively.
H3 and TH4, specifically, the threshold value TH2 is set to, for example, 0.15, the threshold value TH3 is set to, for example, 0.3,
The threshold value TH4 is set to, for example, 0.3. In particular, since the head position of the child SP when seated is difficult to stabilize, head data is removed in advance in the determination process. Therefore, as shown in FIG.
The ratio of each signal data to the sum Sum of the signal data relating to the current flowing through each antenna electrode excluding the data is calculated.
TH3 is set.

Therefore, various kinds of arithmetic processing are performed on actual signal data relating to currents flowing through the plurality of antenna electrodes 4a to 4f taken into the control circuit 20. For example, the sum S of the signal data is compared with a threshold value The to determine whether or not the sheet 1 is vacant (Empty). The ratio of the individual signal data to the sum S of the actual signal data is compared with a threshold value TH1 to identify the occupant's head position. Further, the ratio of each signal data to the sum Sum of the signal data from which the head data is removed is determined by a threshold value T.
H2, TH3, and TH4 are compared to determine whether the occupant is a child or an adult. Based on this decision,
The airbag device 30 shown in FIG. 5 is set so that the airbag can be deployed or cannot be deployed according to a transmission signal from the control circuit 20. That is, the transmission signal from the control circuit 20 is input to the control circuit CC of the airbag device 30, and when the occupant is a child, the occupant does not supply a signal to the gate of the semiconductor switching element SW2 on the passenger seat side. Is set to supply a signal to the gate of the switching element SW2. Therefore, the passenger side airbag is not deployed in the case of a child, and is deployed in the case of an adult. Note that the driver's seat side airbag is deployed regardless of the situation on the passenger seat side.

Next, the processing flow of the occupant detection system will be described.
Will be described with reference to FIGS. First, FIG.
As shown in (1), the ignition switch is turned on to start. Initialization is performed in step S1, and the process proceeds to step S2. In step S2, an initial diagnosis relating to the communication system between the control circuit 20 and the airbag device 30 is performed. In step S3, it is determined whether or not the engine has started. If it is determined that the engine has started, the process proceeds to step S4, and if it is determined that the engine has not started, the process returns. . In step S4, a plurality of antenna electrodes 4
Signal data relating to a current flowing based on the weak electric field selectively generated around (4a-4f) is transmitted to the control circuit 20.
Captured (received). In step S5, it is determined whether or not the occupant is seated on the seat, the occupant's head position, and whether or not the occupant is a child based on the arithmetic processing data of the received signal data. Further, in step S6, SRS communication is performed with the airbag device (SRS) 30 based on the determination result in step S5. When step S6 ends, the process returns to step S4 again, and the processing from step S4 to step S6 is repeatedly performed.
Step S3 can be omitted.

The initial diagnosis in FIG. 8 is performed, for example, as shown in FIG. First, in step SA1, the fixed data
From the control circuit 20 to the control circuit C of the airbag device 30.
Send to C. In step SA2, the airbag device 30
Receive the transmission data from. Then, Step SA3
Then, it is determined whether or not the fixed data transmitted from the control circuit 20 to the airbag device 30 and the received data from the airbag device 30 match. If it is determined that the respective data match, the processing flow is continued. If it is determined that the respective data do not match, it is determined that there is an abnormality in the communication system, a fail-safe process is performed, and, for example, a warning lamp is turned on. In this initial diagnosis, fixed data is transmitted from the airbag device 30 to the control circuit 20, and the transmitted data from the control circuit 20 is determined by the control circuit CC of the airbag device 30 regarding the coincidence. You may do so.

The signal reception in FIG. 8 is performed, for example, as shown in FIG. First, in step SB1, based on a signal from the control circuit 20, the switching means 18a to 18f of the switching circuit 18 are switched to the switching means 18a.
Only, only the switching means 18b, only the switching means 18c,.
b, 4c... 4f are sequentially selected. Step SB
Signal de relates to a current flowing through the 2 each antenna electrode 4a-4f - data _{(t 1, t 2 ··· t} 6) is received by the control circuit 20 proceeds to step SB3. In step SB3, the switching means 18a-1 of the switching circuit 18
It is determined whether the switching of the antenna electrodes 4a to 4f based on the selective closing of 8f has been completed. If it is determined that all the switching operations have been completed, the occupant determination flow is continued. If it is determined that all the switching has not been completed, the process returns to step SB1.

The occupant determination in FIG.
This is performed as shown in FIG. First, in step SC1, the signal data tn relating to the current flowing through the selected antenna electrodes 4a to 4f are individually set from n = 1 to k (6 from the antenna electrodes 4a to 4f) (t). ₁ , t ₂ ... T ₆ ) is calculated. In step SC2, the sum S is compared with a threshold value THe for discriminating whether the seat is vacant or not, and it is determined whether the sum S is larger than the threshold value THe. If it is determined that the sum S is larger than the threshold value THe, the process proceeds to step SC.
3 and if it is determined that it is not large, step SC1
Go to 5. Step SC3 In sum de - individual signals de against data S - ratio of data _{(t 1, t 2 ··· t} 6) (T
n = T ₁ , T ₂ ... T ₆ )
Proceed to 4. In step SC4, the number n of antenna electrodes is 1.
It is determined whether or not from 6 to 6 is smaller than 5. If n is 1 to 4, it is determined that n is smaller than 5, and the process proceeds to step SC5. If n is 5 to 6, it is determined that n is not smaller than 5, and the process proceeds to step SC6. Step SC5 the ratio de - data Tn is greater than Tn _+1, and the ratio de - or data Tn ₊₁ is less than the threshold value TH1 is determined. For example, as shown in FIG. 6B, when n = 1, the ratio data T ₁ is larger than T ₂ and the ratio data T _1
2 from the smaller threshold TH1, the ratio de - antenna electrode 4b portions corresponding to the data T ₂ is the neck, it is determined antenna electrode 4a portion located adjacent thereon as is the head step Proceed to SC7. In step SC7 that de - data NTn (de - data T _1), as shown in FIG. 6 (c), are excluded as 0. If n is 2 or more in step SC5, the above condition is not satisfied, and the process proceeds to step SC6. In step SC6 that de - data NTn is Tn - it is (de data _{T 2, T 3 ··· T 6} ). In step SC8, the sum of the individual data (T ₁ = 0, T ₂ , T ₃ ... T ₆ ) from n = 1 to k (6) for the data NTn from which the head data has been removed. Sum is calculated, and the flow advances to step SC9. At step SC9, the ratio (Tn = T ₁ , T ₂ ... T ₆ ) of each signal data NTn to the sum data Sum is calculated, and the routine proceeds to step SC10. In step SC10, the ratio data T
₁ through T ₄ is smaller than the threshold value TH2, and a ratio de - or data T ₅ or T ₆ is larger than the threshold TH3 is determined. If this condition is satisfied, it is determined in step SC11 that the occupant is a child. If this condition is not satisfied, the flow advances to step SC12. Step SC12 in all de - data T ₁ through T ₆ the threshold TH4 is smaller than or not. When this condition is satisfied, step SC
At 13, it is determined that the occupant is an adult, and if this condition is not satisfied, the process proceeds to step SC14, where it is determined that the occupant is gray (GRAY), neither an adult nor a child. For example, in FIG. 6C, the ratio data T _{1 to} T ₄ are equal to the threshold value T.
Less than H2, and the ratio de - since the data T ₅ or T ₆ is larger than the threshold value TH3, it identifies that the occupant is a child. Moreover, and FIG. 7 (b) in a ratio de - since data T ₁ through T ₆ is less than all the threshold TH4, does not satisfy the above condition, the passenger can be identified to be an adult. If it is determined in step SC2 that the sum S of the signal data is not larger than the threshold value THe, it is determined in step SC15 that the sheet is empty (Empty). If it is determined in step SC11 that the occupant is a child, the process proceeds to step SC16, where an O for preventing the airbag of the airbag device 30 from being deployed is set.
The FF data is set and the SRS data communication flow is continued. If it is determined in step 13 that the occupant is an adult, the process proceeds to step SC17, where ON data for deploying the airbag of the airbag device 30 is set, and the processing flow is continued.
It should be noted that the process proceeds to step SC17 in both the case of vacant seat and the case of GRAY.

The SRS data communication in FIG. 8 is performed, for example, as shown in FIG. First, in step SD1, an ON state is set from the occupant detection unit side (control circuit 20) to the airbag apparatus side (control circuit CC) so that the airbag of the airbag apparatus 30 can be deployed or cannot be deployed. -Data or OFF data and check data
Data is sent. In step SD2, OK data or NG data and check data for ON data or OFF data from the airbag apparatus are received, and the flow advances to step SD3. In step SD3, it is determined whether the ON / OFF data and the check data transmitted from the occupant detection unit to the airbag device are returned to the occupant detection unit from the airbag device again in a normal state. You. If it is determined that the communication is normal (there is no abnormality in the communication system), the processing flow is continued. If it is determined that the communication system is abnormal, the flow advances to step SD4 to determine whether the fail-safe timer has reached zero. The abnormality detection of the communication system is set to, for example, three times. Therefore, when it is determined that the fail-safe timer has reached zero, a fail-safe process is performed, for example, a warning light is turned on. If it is determined that the fail-safe timer has not become zero, the process proceeds to step SD5, and
The self-timer counts, and the processing flow is continued.

On the other hand, in step SE1, the airbag device side (control circuit CC) is connected to the occupant detection unit side (control circuit 2).
From 0), ON data or OFF data and check data for making the airbag of the airbag device 30 deployable or undeployable are received. Then, in step SE2, the reception data is checked to determine whether the reception data has been normally received. In any case, the process proceeds to step SE3, where O
K data or NG data and check data are transmitted to the occupant detection unit. If it is determined in step SE2 that there is no abnormality in the communication system, the OK data in step SE3 is output.
The process proceeds to Step SE4 via the data transmission step. In step SE4, the data on the airbag device side is updated based on the OK data. As a result, the airbag is updated and set to one of a deployable state and an undeployable state. If it is determined in step SE2 that there is something wrong with the communication system, the flow advances to step SE5 via the NG data transmission step of step SE3. In this step SE5, it is determined whether or not the fail-safe timer has become zero. Incidentally, the abnormality detection of this communication system is, for example, 3
Set to times. Therefore, when it is determined that the fail-safe timer has reached zero, a fail-safe process is performed, for example, a warning light is turned on. If it is determined that the fail-safe timer has not become zero, the process proceeds to step SE6, where the fail-safe timer is counted, and the processing flow is continued.

According to this embodiment, the antenna electrodes 4 (4a to 4f) facing the head, neck, shoulder, back, etc. of the occupant sitting on the seat 1 are provided with the respective seats. Since the current flows according to the difference in the contact area (opposed area) with the head, the head position can be easily detected from the position of the neck by comparing the magnitude relationship of the signal data for each current. be able to. Therefore, since the head position is substantially linked to the sitting height, it is possible to easily determine whether or not the occupant is a child based on the head position.

Further, since the head position of a child in a seated state tends to lack stability, signal data relating to the head is also low in reliability. Therefore, prior to discriminating whether or not the occupant is a child, the head data is removed from the detection data corresponding to other human body parts, so that the head posture of the occupant is significantly affected. It is possible to accurately determine whether or not the occupant is a child, and at that time,
If the individual signal data is converted into the ratio of the sum of the signal data to the sum Sum, the reliability of the determination is further improved without being affected by the change in the absolute value of the output signal due to the occupant's clothes, body shape and the like. be able to. Therefore, the airbag device 3
The zero airbag can be reliably set to either the deployable state or the undeployable state based on accurate occupant determination, and can prevent undesired deployment.

In particular, a current flows through a plurality of band-shaped antenna electrodes 4 (4a to 4f) arranged on the backrest 1b of the sheet 1 based on a weak electric field generated by application of a high-frequency low voltage. The individual signal data for
The thresholds TH1, TH2, TH3, and TH4 for various determinations of the occupant are set for the ratio. For this reason, even when the occupant's clothes become thick, for example, even if the absolute values of the individual signal data fluctuate as shown by the dotted lines in FIGS. The data hardly fluctuates as shown in FIGS. 6 (b) and 7 (b). Therefore, even if the absolute value of each signal data varies depending on the body shape and the thickness of the occupant's clothes, it is not necessary to change the threshold value for various determinations of the occupant each time. Highly reliable judgment can be expected.

It should be noted that the present invention is not limited to the above embodiment, and the number of antenna electrodes arranged on a sheet can be appropriately increased or decreased. Further, the electric field generating means is configured to generate an almost square-wave high-frequency low voltage with only the positive power supply by performing a switching operation based on a pulse signal from the control circuit, in addition to the oscillation circuit that generates the high-frequency low voltage. And its output frequency is 100KH
An appropriate frequency other than z can be set, and the voltage can be used outside the range of 5 to 12 V. Further, the amplitude control circuit can be omitted depending on the accuracy of the system power supply, the function expected of the system, and the like. Also, as the adult determination flow in the occupant determination flow, step S
If the condition of C10 is not satisfied, it may be configured to be judged as an adult. Further, at the end of the sheet (sheet
It is also possible to arrange an antenna electrode on the support portion to detect a child falling asleep and prevent the side airbag from being deployed.

[0039]

As described above, according to the present invention, since a plurality of band-shaped antenna electrodes are arranged on the back portion of the seat, when the occupant sits on the seat, Since current corresponding to the difference in the contact area (facing area) with the sheet of each part flows through the antenna electrodes facing the head, neck, shoulder, back, etc., the signal data relating to each current flows. The head position can be easily detected from the position of the neck portion by comparing the magnitude relation of the heads. Therefore, since the head position is substantially linked to the sitting height, it is possible to easily determine whether or not the occupant is a child based on the head position.

Prior to discriminating whether or not the occupant is a child, the head data is removed from the detection data corresponding to other human body parts, so that the occupant's head is removed. It is possible to accurately determine whether or not the occupant is a child without being affected by the state even when the vehicle is leaning forward or leaning sideways. If the data is converted into a ratio to the sum of the signal data, the reliability of the determination can be further improved without being affected by the change in the absolute value of the output signal due to the occupant's clothes, body shape, and the like.
Therefore, the airbag of the airbag device can be reliably set to one of the deployable state and the undeployable state based on accurate occupant determination, and undesired deployment can be prevented.

[Brief description of the drawings]

FIGS. 1A and 1B are diagrams for explaining a basic operation of an occupant detection system according to the present invention, wherein FIG. 1A shows an electric field distribution around an antenna electrode, and FIG. The figure which shows the electric field distribution when an object exists in the vicinity.

FIGS. 2A and 2B are diagrams showing a vehicle interior part of the occupant detection system according to the present invention, wherein FIG. 2A is a side view showing an arrangement state of antenna electrodes on a sheet, and FIG. The front view of figure (a).

3 is a specific configuration diagram of the antenna electrode shown in FIG. 2, wherein FIG. 3A is a plan view, and FIG. 3B is a cross-sectional view of FIG.

FIG. 4 is a circuit block diagram of an occupant detection system according to the present invention.

5 is a circuit block diagram of the airbag device shown in FIG.

FIG. 6 is a current pattern when a child is seated on a sheet.
5A is a signal data diagram based on a current flowing through each antenna electrode, FIG. 5B is a ratio data diagram for the sum, and FIG. 5C is a head data diagram. FIG. 6 is a signal data diagram showing a state where data is removed.

FIG. 7 is a current pattern when an adult is seated on a sheet.
5A is a signal data diagram based on a current flowing through each antenna electrode, and FIG. 5B is a ratio data diagram with respect to the sum.

FIG. 8 is a flowchart of occupant detection by the occupant detection system according to the present invention.

FIG. 9 is a flowchart of an initial diagnosis shown in FIG. 8;

FIG. 10 is a flowchart of signal reception shown in FIG. 8;

FIG. 11 is a flowchart of the first half of the occupant determination shown in FIG. 8;

FIG. 12 is a flowchart of the latter half of the occupant determination shown in FIG. 8;

FIG. 13 is a flowchart of the SRS communication shown in FIG. 8;

FIG. 14 is a circuit block diagram of an airbag device according to a conventional example.

FIG. 15 is a circuit block diagram of an improved airbag device according to a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 sheet 1a Seated part 1b Backrest part 4 (4a, 4b ... 4f) Antenna electrode 5 Base member 6 (6a, 6b ... 6f) Lead wire 10 Control unit 11 Electric field generating means (Oscillation Circuit) 15 Current detection circuit 16 AC-DC conversion circuit 17 Amplifier 18 (18a, 18b ... 18f) Switching circuit 19a, 19b ... 19f Connector (terminal) 20 Control circuit 22 Power supply circuit 30 Airbag device SS1, SS2 Safety sensor SQ1, SQ2 Squib SW1, SW2 Semiconductor switching element CC Control circuit GS Electronic acceleration sensor

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Kazunori Jinno 1-4-4 Shiro, Chuo-ku, Osaka-shi, Osaka Within NEC Home Electronics Co., Ltd. (72) Satoshi Baba Shiro, Chuo-ku, Osaka-shi, Osaka 1-4-24, NEC Within Home Electronics Co., Ltd. (72) Inventor Tsutomu Fukui 1-4-1, Chuo, Wako-shi, Saitama Prefecture Honda R & D Co., Ltd. (72) Nobuhiro Koshiroda Wako-shi, Saitama 1-4-1, Chuo Inside Honda R & D Co., Ltd. (72) Inventor Takashi Ino 1-4-1 Chuo, Wako City, Saitama Pref. Inside Honda R & D Co., Ltd. (72) Inventor Kazumasa Isonaga Wako, Saitama 1-4-1 Chuo F-term in Honda R & D Co., Ltd. (Reference) 2F063 AA49 BA29 BD09 CA09 DA05 DA23 DD06 JA10 LA09 ZA01 3B087 CD04 DE08 3D054 AA03 AA14 DD28 EE09 EE10 EE11 EE14 EE31 EE39 EE57 FF16

Claims (5)

[Claims] 1. A plurality of strip-shaped antenna electrodes arranged at substantially regular intervals in a vertical direction on a backrest of a sheet, and electric field generating means for generating a weak electric field around the antenna electrodes; Among the plurality of antenna electrodes, a weak electric field is generated around a specific antenna electrode, and a current detection circuit for detecting a current flowing based on the electric field, and a head based on signal data taken in from the current detection circuit. And a control circuit for detecting whether the occupant is a child based on signal data from which data on the head has been removed when the head is detected. Occupant detection system. 2. A plurality of strip-shaped antenna electrodes arranged at substantially constant intervals in the vertical direction on the backrest of the sheet, and electric field generating means for generating a weak electric field around the antenna electrodes; Among the plurality of antenna electrodes, a weak electric field is generated around a specific antenna electrode, and a current detection circuit for detecting a current flowing based on the electric field, and a head based on signal data taken in from the current detection circuit. And a control circuit for determining whether or not the occupant is a child based on signal data obtained by removing data relating to the head when the head is detected, and an airbag based on the collision. An airbag device having a function of deploying the airbag, transmitting data based on the determination result of the control circuit to the airbag device, and deploying or not deploying the airbag of the airbag device. of An occupant detection system characterized by being set to either one of them. 3. The control circuit calculates a ratio of each signal data to a total of the signal data taken in from the current detection circuit, and compares and compares the ratio data applied to adjacent antenna electrodes. The head is detected by comparing the data with threshold data on the head stored in advance, and if a head is detected, the sum of signal data from which the data on the head has been removed. Is determined by determining the ratio of individual signal data with respect to the occupant and comparing the ratio data with a threshold value stored in advance for identification of the occupant. The occupant detection system according to claim 1, wherein the occupant detection system is controlled. 4. A weak electric field is selectively generated around a plurality of strip-shaped antenna electrodes which are vertically spaced apart from each other at substantially constant intervals on a backrest of the sheet, and a current flowing based on the electric field is generated. Detecting the head based on the signal data related to the head, and determining whether the occupant is a child based on the signal data obtained by removing the data related to the head when the head is detected. An occupant detection method characterized by the following. 5. A weak electric field is selectively generated around a plurality of strip-shaped antenna electrodes arranged at substantially constant intervals in a vertical direction on a backrest of a sheet, and a current flowing based on the electric field is generated. Of the individual signal data with respect to the sum of the signal data of the heads, the head is detected based on the ratio data, and when the head is detected, the data on the head is removed. By determining the ratio of each signal data to the sum of the signal data and comparing the ratio data with a threshold value stored in advance for identifying the occupant, whether or not the occupant is a child is determined. And determining whether the airbag of the airbag device is in a deployable state or an undeployable state based on the determination result.