JP3476682B2 - Occupant detection system and occupant detection method - Google Patents

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 in accordance with the occupant's seating condition in the passenger seat of an automobile equipped with the airbag device. Alternatively, the present invention relates to an improvement in an occupant detection system and an occupant detection method that can be set in an undeployable state.

[0002]

2. Description of the Related Art Generally, an airbag device is a device for alleviating an impact on an occupant in a vehicle collision.
It has become indispensable for the safety of automobiles, and it is recently installed not only in the driver's seat but also in the passenger seat.

This airbag device is provided with a safing sensor SS1 and a squib SQ as shown in FIG.
1, a squib circuit on the driver's seat side consisting of a series circuit of a semiconductor switching element SW1 such as a field effect transistor, a safing sensor SS2, a squib SQ2, and a semiconductor switching element SW such as a field effect transistor
2 squib circuit on the passenger side, electronic acceleration sensor (collision detection sensor) GS, and electronic acceleration sensor G
The control circuit CC has 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 air bag device, when a car collides for some reason, the safing sensors SS1 and SS2 are closed by the switch contacts thereof reacting to a relatively small acceleration. The squib circuit on the passenger side becomes operable. Then, when the control circuit CC determines that the vehicle has surely collided on the basis of 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. It turns on. This results in current flowing through each squib circuit,
Due to the heat generation of 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.

By the way, in this air bag system, the air bag is inflated when a vehicle crashes regardless of whether or not the occupant is seated in the seat. When the passenger is seated, the above-mentioned occupant protection effect can be expected in the event of a collision, but when the occupant is a child, the head position is low. Is concerned. Therefore, it is recommended that the airbag should not be deployed even if a vehicle collides.

[0006]

Therefore, conventionally, in order to deal with such a problem, an airbag device as shown in, for example, FIG. 15 has been proposed. This airbag device is provided with a sensor SD for detecting whether or not a passenger is seated in the passenger seat, and the control circuit CC determines the seating status of the passenger in the passenger seat based on the detection signal of the sensor SD. When an automobile collides, the airbag is set to either a deployable state or an undeployable state. In particular, it has been proposed that the sensor SD uses a weight sensor for measuring the weight, and that the occupant seated in the seat is photographed by a camera and image processing is performed to determine whether it is an adult or a child. There is.

According to the former method, it is possible to roughly judge whether the occupant is an adult or a child, and based on this result, the airbag is set to either the inflatable state or the inflatable state. Although it is possible to avoid an unforeseen situation at the time of collision of a car, there is a problem in that the weight is largely different among individuals, and even if a child is heavier than an adult, accuracy is insufficient.

Further, according to the latter method, although it is possible to judge the occupant's seating condition and whether the occupant is an adult or a child fairly accurately, various types of patterns are obtained by image-processing the image pickup data photographed by the camera. The processing equipment is complicated and expensive, especially because
When the occupant is a child, the position of the head is unstable, so that not only the pattern recognition becomes complicated, but also the processing becomes more complicated.

Therefore, an object of the present invention is to accurately identify the occupant seated in the seat without being significantly affected by the seating posture of the occupant, and based on this 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]

Therefore, in order to achieve the above-mentioned object, the present invention provides a plurality of strip-shaped antenna electrodes vertically spaced apart from each other on a backrest portion of a seat. An electric field generating means for generating a weak electric field around the antenna electrode and one antenna electrode
The head of the head based on the signal data fetched from the current detection circuit, which generates a weak electric field around the selected antenna electrode and detects the current flowing based on this electric field. And a head is detected, the control circuit determines whether or not the occupant is a child based on the signal data from which the data related to the head is removed.

A second aspect of the present invention is to generate a weak electric field around a plurality of strip-shaped antenna electrodes which are vertically spaced apart from each other on the backrest portion of the seat at substantially regular intervals. And a plurality of antenna electrodes are sequentially selected one by one , a weak electric field is generated around the selected antenna electrode , and a current flowing based on the electric field is detected. Detects the head based on the current detection circuit and the signal data captured from the current detection circuit,
When a head is detected, a control circuit that determines whether or not the occupant is a child based on signal data from which data related to the head is removed, and an airbag device having a function of deploying an airbag based on a collision And transmitting data based on the determination result of the control circuit to the airbag device,
It is characterized in that the airbag of the airbag device is set to either a deployable state or an undeployable state.

According to a third aspect of the present invention, the control circuit obtains the ratio of individual signal data to the total sum of signal data fetched from the current detection circuit, and applies to adjacent antenna electrodes. The head is detected by comparing the ratio data and comparing the ratio data with prestored threshold data for the head. If the head is detected, the data for the head is detected. The ratio of the individual signal data to the total sum of the signal data from which is removed is calculated, and the ratio data is compared with a prestored threshold value for identifying the occupant, so that It is characterized by being controlled so as to determine whether or not there is.

According to a fourth aspect of the present invention, a plurality of strip-shaped antenna electrodes arranged in the backrest portion of the seat are vertically separated from each other at a substantially constant interval, and the strip-shaped antenna electrodes are sequentially selected one by one.
Generate a weak electric field around the selected antenna electrode ,
The head is detected based on the signal data related to the current flowing based on this electric field, and when the head is detected, it is determined whether or not the occupant is a child based on the signal data from which the data related to the head is removed. It is characterized by

Further, according to a fifth aspect of the present invention, a plurality of strip-shaped antenna electrodes arranged on the backrest portion of the seat are vertically spaced apart from each other at substantially regular intervals and are sequentially selected one by one.
Then , a weak electric field is generated around the selected antenna electrode, the ratio of individual signal data to the sum of signal data related to the flowing current is obtained based on this electric field, and the head is detected based on this ratio data. , When the head is detected, the ratio of the individual signal data to the sum of the signal data from which the data related to the head is removed is obtained, and this ratio data is compared with a threshold value for occupant identification stored in advance. Therefore, it is determined whether or not the occupant is a child, and based on this determination result, the airbag of the airbag device is set to either a deployable state or an undeployable state. .

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS 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 are basically a weak electric field (Electric F) generated in an antenna electrode arranged in a sheet.
ield) is to use the disorder. First, the same figure (a)
As shown in, by applying a high frequency low voltage from the oscillation circuit OSC to the antenna electrode E1,
As a result of the generation of a weak electric field around 1, the antenna electrode E1
A current I flows on the side of. In this state, as shown in FIG. 3B, the object O 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 1 side.

Therefore, the antenna electrode E is used depending on whether the object OB is on the seat of the automobile or not.
A change occurs in the electric current flowing to the side of 1, and by utilizing this phenomenon, it is possible to detect whether or not the occupant is seated in the seat and to identify whether the occupant is a child or an adult. And so on. In particular, by increasing the number of antenna electrodes, it becomes possible to obtain a lot of information about the object (occupant) on the seat, and it is possible to more accurately detect the seating condition of the passenger on the seat.

Next, an embodiment of an occupant detection system according to the present invention using this principle will be described with reference to FIGS. The same parts as those of the conventional example shown in FIGS. 14 to 15 are designated by the same reference numerals, and detailed description thereof will be omitted. 2 to 3 show a passenger seat (driver's seat) according to the present invention, and the seat 1 is mainly a seating portion 1a.
And a backrest portion 1b. Seat 1a
Is composed of, for example, a seat frame 3 fixed to a base 2 which can be slid back and forth, a cushion material arranged above the seat frame 3, and an exterior material covering the cushion material. The backrest portion 1b is configured, for example, by arranging a cushion material on the front side of the seat frame and covering the cushion material with an exterior material. In particular, the backrest 1b has a plurality of strip-shaped antenna electrodes 4 (4a, 4).
b ... 4f) are arranged so as to be vertically separated from each other in a substantially horizontal state, 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 not only inside the exterior material but also outside the exterior material, or can be provided on the exterior material itself. A control unit 10, which will be described later, is arranged in or near the seat frame 3.

The antenna electrode 4 is made of, for example, a conductive cloth, and is made of a thread-shaped metal and has a backrest portion 1b.
The sheet cloth surface may be woven, the surface thereof may be coated with a conductive paint, or a metal plate may be arranged. In particular, as shown in FIG. 3, for example, the antenna electrode 4 has a strip-like shape (for example, width 30 mm, length 280 mm) of the same size on one surface of the base member 5 made of an insulating member.
4f of the antenna electrodes 4a, 4b ... 4f are vertically separated from each other by a predetermined distance (for example, 10 mm),
It is desirable that the backrest portion 1b is configured by being integrated with the backrest portion 1b, and the backrest portion 1b is disposed inside the exterior material. Especially, from the antenna electrodes 4a, 4b ... 4f, the lead wire 6 (6a,
6b ... 6f) 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 seat frame 3 of the above-described sheet 1 or in the vicinity thereof. As shown in FIG. 4, for example, the control unit 10 has a frequency of about 100 KHz. An 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 the 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 a transmission signal, an AC-DC conversion circuit 16 for converting an output signal of the current detection circuit 15 into a direct current, and an AC-DC
An antenna electrode 4a connected to the current detection circuit 15 and having a plurality of switching means 18a, 18b ... 18f, and an amplifier 17 for amplifying the output signal of the conversion circuit 16.
1 to 4f and connectors 19a, 19b ... 1 connected to the switching means 18a to 18f of the 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 supply (not shown), and a power supply circuit 22 connected between the connector 21 and the control circuit 20 and the like. ing. To the control circuit 20 of the control unit 10, for example, an airbag device 30 having the configuration shown in FIG. 5 is connected. The selective switching of the switching means 18a to 18f in the switching circuit 18 is performed based on the signal from the control circuit 20.

In this control unit 10, the amplitude control circuit 12 is composed of, 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. Then, the amplitude variable circuit 13 is, for example, a programmable gain amplifier (PG
The amplitude detection circuit 14 includes a voltage amplitude detection section 14a including, for example, an operational amplifier, and an AC-DC conversion circuit 14b for converting an output signal of the detection section 14a into a direct current. And an amplifier 14c that amplifies 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 amplitude variable signal for the amplitude variable unit 13a is output from the control circuit 20.

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

The occupant detection system configured as described above operates as follows. First, when a high frequency low voltage is transmitted from the oscillation circuit 11, its voltage amplitude is detected by the detection unit 14a of the amplitude detection circuit 14, and the detection signal is A
The amplifier 1 is converted into direct current by the C-DC converter circuit 14b.
It 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 to a predetermined voltage amplitude to the amplitude variable section 13a. This corrects the voltage amplitude of the transmitted signal to the desired amplitude,
After that, the amplitude variable circuit 13 and the amplitude detection circuit 14 cooperate to control the amplitude to a constant value.

The transmission signal whose voltage amplitude is constant is supplied to the antenna electrode 4 through the current detection circuit 15, the switching circuit 18, and the connectors 19a to 19f, and as a result, a weak electric field is generated around the antenna electrode 4. To be done. At this time, the switching circuit 18 is subjected to open / close control by a signal from the control circuit 20, 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. After that, the switching is selectively controlled so that only specific switching means are sequentially closed and other switching means are opened at the same time. Therefore, when the specific switching means (18a to 18f) are closed, the transmission signal whose voltage amplitude is made constant is the current detection circuit 15, the specific switching means (18a to 18f), and the specific connector (1).
9a to 19f) and specific antenna electrodes (4a to 4f).
f), so that the specific antenna electrode (4a
4f), a weak electric field is generated, and different levels of current flow according to the seating posture of the occupant seated in the seat 1. That is, a current flows according to the difference in the contact area (opposing area) with the seat of the occupant's back, shoulders, neck, and head. This current is detected by the current detection circuit 15, and A
The C-DC conversion circuit 16 converts the direct current to an amplifier 17
It is amplified at and input to the control circuit 20 one after another.

The control circuit 20 has a threshold value (threshold value data) THe for identifying whether or not the seat 1 is vacant (Empty) in advance, and for identifying the occupant's head. A threshold value (threshold value data) TH1 and a threshold value (threshold value data) relating to occupant identification (discrimination between child and adult).
(TH) TH2, TH3, TH4 are stored (stored).

That is, regarding the threshold value THe regarding whether or not the seat is vacant, a plurality of antenna electrodes 4 (4a to 4a-4) are obtained by seating a child or an adult occupant on the seat.
Since the total sum S of the output signals based on the current flowing in f) becomes a certain value or more, it is set based on this total sum. This threshold value THe is specifically set to, for example, 20, and if the actual total sum S is greater than 20, it is determined that the occupant is seated, and if the actual total sum is less than 20, it is determined that the passenger is vacant. .

Threshold TH1 for identification of the occupant's head
Regarding the above, regarding the head, neck, shoulders, and back of the occupant, the level of the current flowing through the antenna electrodes 4a to 4f differs depending on the contact area (opposing area) with the seat 1, and the pattern is different. It is set by using the characteristic difference between children and adults. That is, in the case of a child occupant, as shown in FIG. 6A, the level of the current flowing through the antenna electrodes 4c to 4f corresponding to the same portion is the highest in the region below the shoulder, and then the head ( The antenna electrode 4a) and the neck (antenna electrode 4b) are at the lowest level, and in the case of an adult occupant, as shown in FIG.
There is no antenna electrode corresponding to the head portion, and in the region below the neck, the level of the current flowing through the antenna electrodes 4a to 4f corresponding to the same portion is higher from the neck to the shoulder and the back. Therefore, the output signals of the antenna electrodes adjacent to each other in the vertical direction are compared with each other, and it is discriminated that the head is located next to (on the upper side of) the lowest level. Therefore, the threshold TH1 is set as a comparison reference for the level. . In particular, the current flowing through the antenna electrodes depends on the thickness and body shape of the occupant's clothes, and in order to mitigate the effect, the signal data relating to the current flowing through each antenna electrode is shown in FIG. As shown in FIG. 7B and FIG. 7B, it is converted into the ratio to the total sum S of the above output signals.
This threshold value TH1 is specifically set to, for example, 0.13, and the antenna electrode portion that outputs smaller signal data is the neck and the antenna electrode portion above it is the head. Is determined.

FIG. 6 shows the threshold values TH2, TH3 and TH4 relating to the occupant identification (discrimination between child and adult).
As shown in (b) and FIG. 7 (b), it is set by utilizing the fact that the current patterns flowing through the plurality of antenna electrodes are different between a child and an adult. That is, in the case of a child SP,
The output signals (ratio data) from the antenna electrodes 4a to 4d corresponding to the head to the upper back are small, and the output signals (ratio data) from the antenna electrodes 4e to 4f corresponding to the middle and lower parts of the back.
However, in the case of the adult P, a partially protruding output signal (ratio data) is not seen as in the case of the child. Therefore, if the output signals of the antenna electrodes 4a to 4d are smaller than a fixed value and the output signals of any of the antenna electrodes 4e to 4f are larger than the fixed value, the occupant can be determined to be a child, and the condition is not satisfied. above,
If all the 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 the thresholds TH2 and T, respectively.
Corresponding to H3 and TH4, specifically, the threshold value TH2 is, for example, 0.15, the threshold value TH3 is, for example, 0.3,
The threshold TH4 is set to 0.3, for example. In particular, since the head position of the child SP is difficult to stabilize when seated, the 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 related to the current flowing in each antenna electrode excluding the data is calculated, and based on this, the threshold value TH2,
TH3 is set.

Therefore, the actual signal data relating to the currents flowing through the plurality of antenna electrodes 4a to 4f fetched by the control circuit 20 are subjected to various arithmetic processes. For example, the sum S of signal data is compared with a threshold value THe to determine whether or not the seat 1 is vacant (Empty). The ratio of the individual signal data to the total sum S of the actual signal data is compared with the threshold value TH1 to identify the head position of the occupant. Further, the ratio of the individual signal data to the sum Sum of the signal data excluding the head data is a threshold value T.
It is compared with H2, TH3 and TH4 to determine whether the occupant is a child or an adult. Based on this judgment result,
The airbag device 30 shown in FIG. 5 is set so that the airbag can be deployed or undeployed by 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 is prevented from supplying the signal to the gate of the semiconductor switching element SW2 on the passenger side. Is an adult, it is set so as to supply a signal to the gate of the switching element SW2. Therefore, in the case of a child, the airbag on the passenger side is not deployed, and in the case of an adult it is deployed. The driver-side airbag is deployed regardless of the situation on the passenger side.

Next, the processing flow of this occupant detection system.
Will be described with reference to FIGS. 8 to 13. First, FIG.
As shown in, turn on the ignition switch and start. Initialization is performed in step S1, and the process proceeds to step S2. In step S2, an initial diagnosis concerning 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 is starting, the process proceeds to step S4, and if it is determined that the engine is not starting, the process returns. . In step S4, the plurality of antenna electrodes 4
The control circuit 20 outputs signal data relating to a current flowing based on a weak electric field selectively generated around (4a to 4f).
Is received (received) by. In step S5, it is determined whether or not the occupant is seated in the seat, the head position of the occupant, and whether or not the occupant is a child, based on the arithmetic processing data of the captured signal data. Further, in step S6, SRS communication is performed with the airbag device (SRS) 30 based on the determination result of step S5. When step S6 ends, the process returns to step S4 again, and the processes of steps S4 to S6 are repeated.
Incidentally, step S3 can be omitted.

The initial diagnosis in FIG. 8 is performed as shown in FIG. 9, for example. First, in step SA1, a 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
Receives transmission data from. And 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 the communication system is abnormal, fail-safe processing is performed, and, for example, a warning light is turned on. In this initial diagnosis, the fixed data is transmitted from the airbag device 30 to the control circuit 20, and the transmission data from the control circuit 20 is judged by the control circuit CC of the airbag device 30 for the matching. You may do it.

Signal reception in FIG. 8 is performed as shown in FIG. 10, for example. First, in step SB1, the switching means 18a to 18f of the switching circuit 18 are switched to the switching means 18a based on the signal from the control circuit 20.
Only, the switching means 18b only, the switching means 18c only ... Only the specific switching means are sequentially selectively closed, and the specific antenna electrodes 4a, 4
b, 4c ... 4f are sequentially selected. Step SB
In 2, the signal data (t ₁ , t ₂ ... T ₆ ) relating to the currents flowing in the respective antenna electrodes 4a to 4f are taken into the control circuit 20, and the process proceeds to step SB3. In step SB3, the switching means 18a-1 of the switching circuit 18
It is determined whether or not the switching of the antenna electrodes 4a to 4f based on the selective closing of 8f is completed. When it is determined that the switching is completed, the occupant determination flow is continued. If it is determined that 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, with respect to signal data tn relating to the currents flowing through the selected antenna electrodes 4a to 4f, individual signal data (t) from n = 1 to k (6 from antenna electrode 4a to antenna electrode 4f). The sum S of ₁ , t ₂ ... T ₆ ) is calculated. In step SC2, the total sum S is compared with a threshold value THe for identifying whether or not the seat is vacant, and it is determined whether the total sum S is larger than the threshold value THe. If it is determined that the sum S is larger than the threshold value THe, step SC
If it is judged not to be greater than 3, go to 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 ) is calculated, and step SC
Go to 4. In step SC4, the number n of antenna electrodes is 1.
From 6 to 6, it is determined whether or not less than 5. When n is 1 to 4, it is determined that n is smaller than 5, and the process proceeds to step SC5. When 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 Go 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 thus 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} ). At step SC8, the sum of the individual data (T ₁ = 0, T ₂ , T ₃ ... T ₆ ) from n = 1 to k (6) is obtained for the data NTn from which the head data has been removed. Sum is calculated, and the process proceeds to step SC9. Step SC9 In sum de - individual signals de for data Sum - ratio of motor _{NTn (Tn = T 1, T} 2 ··· T 6) is calculated, the flow 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, and if this condition is not satisfied, the process proceeds to step SC12. Step SC12 in all de - data T ₁ through T ₆ the threshold TH4 is smaller than or not. If this condition is met, step SC
In 13, it is determined that the occupant is an adult, and if this condition is not satisfied, the process proceeds to step SC14, and it is determined that the occupant is gray (GRAY) that is neither an adult nor a child. For example, in FIG. 6C, the ratio data T _{1 to} T ₄ are threshold values T _1.
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. Further, in FIG. 7B, since the ratio data T _{1 to} T ₆ are all smaller than the threshold value TH4, it is possible to identify that the occupant is an adult without satisfying the above conditions. If the total sum S of the signal data is not larger than the threshold value THe in step SC2, it is determined in step SC15 that the seat is vacant (Empty). If it is determined in step SC11 that the occupant is a child, the process proceeds to step SC16, in which O is set to prevent the airbag of the airbag device 30 from being deployed.
The FF data is set and the SRS data communication flow is continued. When it is determined in step 13 that the occupant is an adult, the process proceeds to step SC17, the ON data for inflating 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 regardless of whether the seat is vacant or GRAY, but may be configured to proceed to step SC16.

The SRS data communication in FIG. 8 is performed as shown in FIG. 13, for example. First, at step SD1, an ON signal for making the airbag of the airbag device 30 in a deployable state or an undeployable state from the occupant detection unit side (control circuit 20) to the airbag device side (control circuit CC). -Data or OFF data and check data
Data is transmitted. At step SD2, the OK data or NG data and the check data for the ON data or the OFF data are received from the airbag device side, and the process proceeds to step SD3. At step SD3, it is judged whether or not the ON / OFF data and the check data transmitted from the occupant detection unit side to the airbag device side are normal and are returned to the occupant detection unit side from the airbag device side again. It If it is determined to be normal (the communication system is normal), the processing flow is continued. If it is determined that the communication system is abnormal, the process proceeds to step SD4 and it is determined whether or not the fail-safe timer reaches zero. The abnormality detection of the communication system is set to three times, for example. Therefore, if it is determined that the fail-safe timer has become zero, fail-safe processing is performed and, for example, a warning light is turned on. If it is determined that the fail-safe timer has not reached zero, the process proceeds to step SD5 and the fail-safe timer is executed.
The rescue timer is counted and the processing flow is continued.

On the other hand, in step SE1, the airbag device side (control circuit CC) is on the occupant detection unit side (control circuit 2).
From 0), ON data, OFF data, and check data for making the airbag of the airbag device 30 in a deployable state or an undeployable state are received. Then, in step SE2, the reception data is checked to determine whether or not the reception data can be normally received. Whichever judgment is made, the operation proceeds to step SE3, where O
K data or NG data and check data are transmitted to the occupant detection unit side. If it is determined in step SE2 that the communication system is normal, the OK data in step SE3
After the data transmission step, the process proceeds to step SE4. In step SE4, the data on the side of the airbag device is updated based on the OK data. As a result, the airbag is renewed and set to either the deployable state or the undeployable state. If it is determined in step SE2 that the communication system is abnormal, the process proceeds to step SE5 after the NG data transmitting step of step SE3. In step SE5, it is determined whether or not the fail-safe timer has reached zero. It should be noted that this communication system abnormality detection is, for example, 3
Has been set to times. Therefore, if it is determined that the fail-safe timer has become zero, fail-safe processing is performed and, for example, a warning light is turned on. If it is determined that the fail-safe timer has not reached zero, the process proceeds to step SE6, the fail-safe timer is counted, and the processing flow is continued.

According to this embodiment, the antenna electrodes 4 (4a-4f) facing the head, neck, shoulders, back, etc. of the occupant seated in the seat 1 are seated at their respective parts. Since a current flows according to the difference in the contact area (opposing area) and the like, the head position can be easily detected from the neck position 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 the occupant is a child based on the head position.

Further, since the head position of the child in the seated state tends to lack stability, the signal data relating to the head is also unreliable. Therefore, since the head data is removed from the detection data corresponding to other human body parts prior to the determination of whether or not the occupant is a child, the head posture of the occupant is greatly affected. It is possible to accurately determine whether or not the occupant is a child, and at that time,
If each signal data is converted into a ratio to the total sum Sum of signal data, the reliability of judgment is further improved without being affected by the variation of the absolute value of the output signal due to the occupant's clothing, body shape, and the like. be able to. Therefore, the airbag device 3
An airbag of 0 can be reliably set to either a deployable state or an undeployable state based on accurate occupant determination, and undesired deployment can be prevented in advance.

In particular, a current flows through a plurality of strip-shaped antenna electrodes 4 (4a-4f) arranged on the backrest portion 1b of the sheet 1 based on a weak electric field generated by application of a high frequency low voltage, and this current The individual signal data relating to
The threshold values TH1, TH2, TH3 and TH4 for various determinations of the occupant are set for the ratio. For this reason, even if the absolute value of individual signal data fluctuates as shown by the dotted lines in FIGS. 6A and 7A, for example, when the clothing of the occupant becomes thicker, the ratio data is changed. -Data hardly fluctuates as shown in FIGS. 6 (b) and 7 (b). Therefore, it is not necessary to change the threshold value for various judgments of the occupant each time, even if the absolute value of individual signal data fluctuates due to the body shape as well as the thickness of the occupant's clothing, and the reliability is improved. Highly accurate judgment can be expected.

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

[0039]

As described above, according to the present invention, since a plurality of strip-shaped antenna electrodes are arranged at the back portion of the seat, when the occupant is seated on the seat, A current corresponding to the difference in the contact area (facing area) with the sheet at each part flows through the antenna electrodes facing the head, neck, shoulders, back, etc. It is possible to easily detect the head position from the position of the neck portion by comparing the magnitude relationship of the data. Therefore, since the head position is substantially linked to the sitting height, it is possible to easily determine whether the occupant is a child based on the head position.

Further, since the head data is removed from the detection data corresponding to other human body parts prior to the determination of whether or not the occupant is a child, the head of the occupant is removed. It is possible to accurately determine whether or not the occupant is a child without being affected by the state of the occupant such as leaning forward or leaning sideways. By converting the data into a ratio to the total sum of the signal data, the reliability of the determination can be further improved without being affected by the variation in the absolute value of the output signal due to the occupant's clothing, body shape, and the like.
Therefore, the airbag of the airbag device can be reliably set to either the deployable state or the undeployable state based on the accurate occupant determination, and the undesired deployment can be prevented in advance.

[Brief description of drawings]

FIG. 1 is a diagram for explaining a basic operation of an occupant detection system according to the present invention, in which FIG. 1 (a) is a diagram showing an electric field distribution around an antenna electrode, and FIG. 1 (b) is a diagram showing the antenna electrode. The figure which shows the electric field distribution when an object exists in the vicinity.

2A and 2B are views showing a vehicle interior portion of an occupant detection system according to the present invention, in which FIG. 2A is a side view showing an arrangement state of antenna electrodes on a sheet, and FIG. The front view of FIG.

3A and 3B are specific configuration diagrams of the antenna electrode shown in FIG. 2, where FIG. 3A is a plan view and FIG. 3B is a sectional view of FIG. 3A.

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 in the seat.
FIG. 4A is a signal data diagram based on the current flowing through each antenna electrode, FIG. 7B is a ratio data diagram to the sum, and FIG. The signal data figure which shows the state which removed the data.

[Fig. 7] Current pattern when an adult is seated in the seat
6A is a signal data diagram based on the current flowing through each antenna electrode, and FIG. 7B is a ratio data diagram with respect to the sum.

FIG. 8 is a flowchart for detecting an occupant by the occupant detection system according to the present invention.

9 is a flowchart of the initial diagnosis shown in FIG.

10 is a flowchart of the signal reception shown in FIG.

FIG. 11 is a flowchart of the first half of the passenger determination shown in FIG.

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

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

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]

1 sheet 1a Seating section 1b Backrest 4 (4a, 4b ... 4f) Antenna electrode 5 base members 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 circuit 30 airbag device SS1, SS2 safing sensor SQ1, SQ2 squib SW1, SW2 Semiconductor switching element CC control circuit GS Electronic acceleration sensor

Front page continuation (72) Inventor Satoshi Baba 1-4-24 Jomi, Chuo-ku, Osaka-shi, Osaka NEC Home Electronics Co., Ltd. (72) Inventor Tsutomu Fukui 1-1-4 Chuo, Wako-shi, Saitama Stock Company Honda R & D Co., Ltd. (72) Inventor Nobuhiro Koshiro 1-4-1 Chuo, Wako-shi, Saitama Stock Research Laboratories Honda R & D Co., Ltd. (72) Takashi Ino 1-4-1 Chuo, Wako-shi, Saitama Incorporated in Honda R & D Co., Ltd. (72) Inventor Kazumasa Isonaga 1-4-1 Chuo, Wako-shi, Saitama Incorporated in R & D Co., Ltd. (56) Reference JP 11-334451 (JP, A) JP 11 271462 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) B60R 2/16-21/32 G01B 7/00 G01V 3/08 B60N 2/44

Claims (5)

(57) [Claims] 1. A plurality of strip-shaped antenna electrodes, which are vertically spaced apart from each other on a backrest portion of a seat, and electric field generating means for generating a weak electric field around the antenna electrodes. Select antenna electrodes one by one
The current detection circuit that generates a weak electric field around the selected antenna electrode and detects the current flowing based on this electric field, and detects the head based on the signal data captured from the current detection circuit. Then, when the head is detected, the occupant detection system is provided with a control circuit that determines whether or not the occupant is a child based on the signal data from which the data related to the head is removed. 2. A plurality of strip-shaped antenna electrodes arranged on the backrest portion of the seat in the vertical direction at substantially regular intervals, and a plurality of electric field generating means for generating a weak electric field around the antenna electrodes. Select antenna electrodes one by one
The current detection circuit that generates a weak electric field around the selected antenna electrode and detects the current flowing based on this electric field, and detects the head based on the signal data captured from the current detection circuit. However, when the head is detected, a control circuit that determines whether the occupant is a child based on the signal data from which the data related to the head is removed, and an air that has a function of deploying an airbag based on a collision are detected. A back device, transmitting data based on the determination result of the control circuit to the air bag device, and setting the air bag of the air bag device to either a deployable state or an undeployable state. Characteristic passenger detection system. 3. The control circuit obtains a ratio of individual signal data to a sum of signal data fetched from the current detection circuit, compares ratio data applied to adjacent antenna electrodes, and stores the ratio data in advance. If the head is detected by comparing it with the threshold data related to the head, and if the head is detected, the ratio of individual signal data to the sum of the signal data from which the data related to the head is removed is obtained, and this ratio data The occupant detection according to claim 1 or 2, wherein the occupant detection is controlled so as to determine whether or not the occupant is a child by comparing with a threshold value stored in advance for identifying the occupant. system. 4. A plurality of strip-shaped antenna electrodes arranged on the backrest portion of the seat and spaced apart at substantially constant intervals in the vertical direction.
Are sequentially selected one by one , a weak electric field is generated around the selected antenna electrode, and the head is detected based on signal data related to current flowing based on the electric field, If detected, the occupant detection method is characterized by determining whether or not the occupant is a child based on the signal data from which the data relating to the head has been removed. 5. A plurality of strip-shaped antenna electrodes arranged in the backrest portion of the seat at a substantially constant interval in the vertical direction.
One by one , a weak electric field is generated around the selected antenna electrode, and the ratio of individual signal data to the sum of signal data related to the current flowing based on this electric field is obtained, The head is detected based on this ratio data, and when the head is detected, the ratio of each signal data to the sum of the signal data from which the data related to the head has been removed is calculated, and this ratio data is stored in advance. By comparing with the threshold value for identifying the occupant, it is determined whether the occupant is a child, and based on the result of the determination, the airbag of the airbag device can be inflated or undeployable. An occupant detection method characterized by setting either one.