JP3365477B2 - 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 an airbag of an airbag device according to a separation state between an occupant and a dashboard in a passenger seat of an automobile equipped with the airbag device. The present invention relates to an improvement in an occupant detection system and an occupant detection method that can set the vehicle to a deployable state or 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 has a safing sensor SS1, a squib SQ1, and a squib SQ1, as shown in FIG.
A squib circuit on the driver's seat side, which is composed of a series circuit of semiconductor switching elements SW1 such as field effect transistors;
The squib circuit on the passenger side, which includes a semiconductor switching element SW2 such as a safing sensor SS2, a squib SQ2, and a field effect transistor, an electronic acceleration sensor (collision detection sensor) GS, and an electronic acceleration sensor GS output signal The control circuit CC has a function of determining the presence or absence of a collision on the basis of the collision 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, according to this airbag device,
For example, as shown in FIG. 8A, when an adult P is seated in the seat 1, the above-described passenger protection effect can be expected in the event of a collision. However, as shown in FIG. (B), the passenger seat sheet - Child and fixed on sheet 1 sheet - if bets 1A infant SP is sitting backward (R ear F acing I nfant S eat: less, In the case of RFIS), there is a concern that the deployment of the airbag may adversely affect the infant SP, so it is desirable that the airbag does not deploy even if a vehicle collides. Moreover, the same figure (c)
As shown in, when the infant SP is sitting forward on the child seat 1A fixed on the seat 1 of the passenger seat ( F
orward F acing C hild S eat: less, since the air bag by the deployment of the air bag there is a concern that covers the face of the child SP to called FFCS), RFI
As in the case of S, it is desirable that the airbag does not deploy even if the vehicle collides.

Therefore, conventionally, in order to deal with such a problem, for example, an airbag device as shown in FIG. 9 has been proposed. This airbag device is provided with a sensor SD for detecting whether or not an occupant is seated in the passenger seat, and the control circuit C is detected based on a detection signal from the sensor SD.
C determines the occupant's seating status in the passenger seat, and sets the airbag to either the deployable state or the undeployable state when the vehicle collides. In particular, as the sensor SD, it is proposed to use a weight sensor for measuring the weight and to take an image of an occupant seated in the seat with a camera and perform image processing to determine whether it is an adult P or a child SP. Has been done.

According to the former method, it is possible to roughly judge whether the occupant is an adult P or a child SP, and based on this result, the airbag can be inflated or undeployable. Although it is possible to set and avoid unforeseen circumstances in the event of a car collision, there are large individual differences in weight, and children may be heavier than adults, so not only lack accuracy but also RFIS, FFCS.
There is a problem that it is not possible to determine which state of

According to the latter method, the occupant's seating condition, the determination whether the occupant is an adult P or a child SP, a child seat
Although it is possible to judge whether or not the child is in the state of RFIS or FFCS fairly accurately, it is necessary to perform image processing on the imaged data taken by the camera and make a comparison judgment with various patterns. In addition, there is a problem that the processing device becomes complicated and expensive.

[0009]

Therefore, the applicant of the present invention is
Previously, an occupant detection system as shown in FIGS. 10 to 14 was proposed. This occupant detection system is basically a weak electric field (Ele) generated between two electrodes arranged in the sheet.
It uses the disturbance of the ctric field. First, as shown in FIG. 10A, when the oscillation circuit 10 for generating a high frequency low voltage is connected to the electrode E1 and the electrode E2 is connected to the ground, the electrodes E1 and E2 are connected to each other based on the potential difference between the electrodes. An electric field is generated, and a displacement current I is generated on the electrode E2 side.
d flows. In this state, when the object OB is present in the electric field, the electric field is disturbed and a displacement current Id1 different from the displacement current Id flows on the electrode E2 side as shown in FIG. Become. Most objects OB are electrically represented by conductance and capacitance, and are coupled to the ground through the capacitance.

Therefore, the displacement current flowing on the side of the electrode E2 changes depending on whether the object OB is on or off the seat of the automobile. By utilizing this phenomenon, The seating status of an occupant in the seat can be detected. In particular, by increasing the number of electrodes, it becomes possible to obtain a lot of information about the object including the occupant on the seat, and it is possible to more accurately detect the seating condition of the occupant on the seat. .

A specific occupant detection system utilizing this principle will be described with reference to FIGS. 11 to 14. still,
The same parts as those of the conventional example shown in FIGS. 7 to 9 are designated by the same reference numerals, and detailed description thereof will be omitted. FIG. 11 shows a sheet according to the prior art, in which a plurality of electrodes are arranged on the front surface side of the seat 1 of the passenger seat. Specifically, for example, rectangular electrodes E1 and E2 are arranged at the seating portion 1a, and electrodes E3 and E4 having substantially the same shape are arranged at a distance from the backrest portion 1b. These electrodes are made of conductive cloth in consideration of the sitting comfort of the occupant, but thread-like metal is woven into the sheet cloth surface, conductive cloth is attached to the cloth surface, or metal is used. It is also possible to arrange a plate or the like. These electrodes E1 to E4 are connected and incorporated in the circuit shown in FIG. 12 (FIG. 13).

In FIG. 12, the occupant detection system has a frequency of about 100 KHz and a voltage of 10 to 12 V, for example.
An oscillating circuit 10 for generating a high frequency low voltage of about a degree, a load current detecting circuit 11, a transmitting / receiving switching circuit 12, a current / voltage converting circuit 13 having an amplifying function, a bandpass function (unnecessary noise removing function) and A detection circuit (demodulation circuit) 14 having an AC-DC conversion function, an amplification circuit 15, an offset conversion circuit 16, and a control circuit 17 such as an MPU.
And an airbag device 18. FIG.
12 is a more specific version of the circuit of FIG. 12, in which the amplifier circuit 15 is composed of, for example, a first amplifier circuit 15A and a second amplifier circuit 15B each having a gain G of 1 times and 100 times. An analog selection circuit 19 for selecting the output signals of the second amplification circuits 15A and 15B is provided,
The analog selection circuit 19 is controlled by the control circuit 17.

In this system, the load current detection circuit 11 is composed of, for example, an impedance element such as a resistor 11a connected in series with the circuit, and an amplifier 11b for amplifying the terminal voltage of the resistor 11a. 10
The current (load current) supplied to the specific electrode selected from is detected. The transmission / reception switching circuit 12 includes, for example, switching means Aa to Ad for connecting one selected electrode (referred to as a transmission electrode) among the electrodes E1 to E4 to the output side of the oscillation circuit 10, and a transmission electrode. Other electrodes (referred to as receiving electrodes) other than the above are comprised of switching means Ba to Bd for connecting to the current / voltage conversion circuit 13, and switching of each switching means is controlled by the control circuit 17. The transmission / reception switching circuit 12 is preferably composed of a multiplexer circuit. The current / voltage conversion circuit 13 includes, for example, an impedance element such as a resistor 13a that converts a displacement current flowing on the receiving electrode side into a voltage, and an amplifier 13 that amplifies the converted voltage.
b and are provided corresponding to the respective electrodes E1 to E4. The analog selection circuit 19 includes, for example, four switching means 19a that are selected and connected all at once to the output side of the second amplification circuit 15B, and four switching means 19 that are selected and connected all at once to the output side of the first amplification circuit 15A. It is composed of a switching means 19b.

The system thus constructed operates as follows. First, when only the switching means Aa of the transmission / reception switching circuit 12 is connected to the output side of the oscillation circuit 10 based on the signal from the control circuit 17, and the switching means Bb to Bd are connected to the current / voltage conversion circuit 13. ,
A high frequency low voltage is applied from the oscillator circuit 10 to the transmission electrode E1, and a displacement current flows through the reception electrodes E2 to E4. This current is converted into a voltage by the resistor 13a, amplified by the amplifier 13b, and output to the detection circuit 14. On the other hand, the load current flowing through the transmission electrode E1 is detected by the load current detection circuit 11 and output to the detection circuit 14 as data R (1,1) described later. In this detection circuit 14, for example, a signal of about 100 KHz is band-passed and
Unwanted noise components are removed based on the C-DC conversion function and output to the first and second amplification circuits 15A and 15B. The output signals of the first and second amplifier circuits 15A and 15B are supplied to the offset conversion circuit 16 and the analog selection circuit 19 respectively.
Are appropriately selected by the operations of and and are output to the control circuit 17. For example, when the output signal from the detection circuit 14 is measurable in the full range, only the four switching means 19b of the analog selection circuit 19 are simultaneously selected and connected to the output side of the first amplification circuit 15A. Further, when the output signal is small and it is difficult to measure a subtle change in the full range, only the four switching means 19a of the analog selection circuit 19 are simultaneously selected and connected to the output side of the second amplification circuit 15B. . Then, in the control circuit 17, the first and second
The output signals from the amplifier circuits 15A and 15B are subjected to A / D conversion and then stored in the memory.

Next, based on the signal from the control circuit 17, the switching means Aa of the transmission / reception switching circuit 12 is opened, only the switching means Ab is connected to the output side of the oscillation circuit 10, and the switching means Ba, Bc, Bd is the current
When connected / changed to the voltage conversion circuit 13, a high frequency low voltage is applied from the oscillation circuit 10 to the transmission electrode E2,
A displacement current flows through 1, E3 and E4. This current is converted into a voltage by the resistor 13a, amplified by the amplifier 13b, and output to the detection circuit 14. The load current flowing through the transmission electrode E2 is detected by the load current detection circuit 11 and output to the detection circuit 14 as data R (2,2) described later. It is processed in the same manner as described above and stored in the control device 17 as data. Then, the switching means Ac
Connect only the output side of the oscillator circuit 10, and connect the switching means Ba, Bb, Bd to the current / voltage conversion circuit 13.
When changed, a high frequency low voltage is applied from the oscillation circuit 10 to the transmission electrode E3, and a displacement current flows through the reception electrodes E1, E2, E4. The load current flowing through the transmission electrode E3 is detected by the load current detection circuit 11, and the data R
It is output to the detection circuit 14 as (3, 3). further,
When only the switching means Ad is connected to the output side of the oscillation circuit 10 and the switching means Ba, Bb, Bc are connected / changed to the current / voltage conversion circuit 13, a high frequency low voltage is applied from the oscillation circuit 10 to the transmission electrode E4. Receiving electrode E1,
A displacement current flows through E2 and E3. These displacement currents are converted into a voltage by the resistor 13a, amplified by the amplifier 13b, and output to the detection circuit 14. The transmission electrode E
The load current flowing through the detector 4 is detected by the load current detection circuit 11, and is detected as data R (4, 4) described later by the detection circuit 1.
4 is output. The controller 17 is processed in the same manner as described above.
Is stored as data.

Then, the control circuit 17 calculates the seating pattern by arithmetically processing these data. The control circuit 17 stores various seating patterns in advance, and the seating patterns calculated by data based on various combinations of the transmission electrodes and the reception electrodes of the electrodes E1 to E4 are stored in advance. The seating pattern is compared with the stored seating pattern to extract and determine the seating pattern. In this control circuit 17, for example, various seating patterns described below are used.
Are subject to judgment. Specifically, the seat is vacant pattern in which no passenger is seated, the child seat is FFCS pattern in which the child is seated in the FFCS state, and the child seat is in the RFIS state in the child seat. R seated at
The FIS pattern is a person pattern in which an adult is seated in the seat, and the electrodes E1 to E4 are appropriately selected and various combinations of the transmitting electrode and the receiving electrode are used.
The data represented by the general formula R (i, j) is obtained. In the general formula R (i, j), i = j is transmission data and i ≠.
j represents reception data, and i represents a transmission electrode and j represents a reception electrode. The control circuit 17 performs arithmetic processing using, for example, 16 pieces of data for each pattern, and the characteristics of the seating pattern are extracted.

When the seating pattern is detected and specified by the control circuit 17, a signal based on the detected seating pattern is transmitted to the airbag device 18. For example, seating pattern is vacant, FFC
In the case of S or RFIS, a signal is sent to the airbag device 18 so that the airbag will not be deployed even if a vehicle collides, and the airbag will be deployed in other patterns. A signal for setting to is transmitted. These signals are input to the control circuit CC of the airbag device 18, and in the case of the former pattern, they are set so that no gate signal is supplied to the semiconductor switching element SW2 on the passenger side at the time of a collision. A gate signal is supplied to the semiconductor switching element SW1 on the driver's seat side. In the latter case, the semiconductor switching elements SW1 and SW2 are set so that the gate signal is supplied.

According to this prior art, a plurality of electrodes E1 to E4 are arranged on the front surface side of the sheet 1, and between one selected transmission electrode and a reception electrode other than the transmission electrode. Since a weak electric field is generated by applying a high frequency low voltage, a displacement current related to the seating pattern of the occupant on the seat 1 flows on the receiving electrode side. Therefore, the seating pattern of the occupant can be accurately detected by determining the characteristic pattern of the displacement current. For this reason, the airbag of the airbag device 18 can be set to either a deployable state or an undeployable state according to the seating pattern of the occupant.

Moreover, since the plurality of electrodes are arranged apart from each other in the sheet 1, the number of combinations of transmitting electrodes and receiving electrodes can be increased, and the number of obtained data can be increased. -It is possible to more accurately determine the seating pattern of the occupant.

The control circuit of the system is, for example, RF.
Since the current pattern characterized by the current flowing through each electrode based on the seating patterns of IS, FFCS, Person, and Empty is stored in advance as the seating pattern, the transmitting electrode and the receiving electrode are appropriately selected. By comparing the received signal data obtained by combining the seating patterns stored in advance with various kinds of seating patterns stored in advance, and extracting the corresponding stored seating patterns, the actual seating pattern can be accurately obtained.
It is possible to obtain an excellent effect such as the detection of noise.

However, recently, when a vehicle equipped with an airbag device collides with an obstacle or the like, for example, an occupant seated in the passenger seat despite the airbag of the airbag device being deployed. It has been pointed out that, for example, the face may be damaged.

As shown in FIG. 15, this is an airbag device when the upper half of the occupant P in the passenger seat, especially the face, is considerably close to the dashboard DB (for example, about 20 cm) due to the impact of a car collision. When the airbag is deployed, the occupant P receives a great impact from the airbag which is deployed on the face and greatly inflates, and the upper body is forcedly pushed back to the backrest side. Therefore, the occupant P is likely to be damaged on the face and the like.

Therefore, recently, from the viewpoint of safety, the user can not only reliably detect whether or not the occupant is seated in the seat, but also the occupant approaches the dashboard due to a collision or the like. There is a demand for an occupant detection system capable of avoiding damage to the occupant caused by the airbag device even when the occupant is too much.

Therefore, an object of the present invention is to accurately detect the distance between the occupant seated in the seat and the dashboard, and to control whether or not the airbag device is operating based on the detection result. An occupant detection system and an occupant detection method are provided.

[0025]

SUMMARY OF THE INVENTION Therefore, in order to achieve the above-mentioned object, the present invention provides a first antenna electrode disposed in a seat portion in a vehicle compartment and a dashboard facing the seat. A second antenna electrode arranged in the antenna part, an oscillator circuit for generating a weak electric field between the first antenna electrode and the second antenna electrode, and a transmission current flowing from the oscillator circuit to the first antenna electrode. A current detection circuit for detecting
A current / voltage conversion circuit that detects a displacement current flowing based on a weak electric field generated between the first antenna electrode and the second antenna electrode and converts it into a voltage, a current detection circuit, and a current / voltage conversion circuit And a control circuit that determines whether or not the distance between the occupant seated in the seat and the dashboard is appropriate based on the output signal of the vehicle.

The second aspect of the present invention is a vehicle interior cabin seat.
Electric field between the first antenna electrode disposed in the first antenna electrode, the second antenna electrode disposed in the dashboard portion facing the sheet, and the second antenna electrode disposed in the dashboard portion facing the sheet. And an electric current detection circuit for detecting a transmission current flowing from the oscillation circuit to the first antenna electrode, and a weak electric field generated between the first antenna electrode and the second antenna electrode. Based on the output signal of the current detection circuit and the current / voltage conversion circuit, the occupant sitting in the seat and the dashboard are detected. And an airbag device having a function of deploying an airbag based on a collision, and sends data based on the determination result of the control circuit to the airbag device. And, wherein the set to either the deployable state or deployed impossible state of the air bag of the air bag device.

According to a third aspect of the present invention, the first antenna electrode is arranged in the seating portion of the seat, and the second antenna electrode is placed in the dashboard portion by a collision or the like. The fourth aspect of the invention is characterized in that the control circuit is arranged in advance so that the facing area with at least a part of the occupant approaching the vehicle is as large as possible. When the level change occurs in the transmission current to the first antenna electrode, it has the corresponding threshold data, and the threshold data or the second antenna electrode side is changed based on the change. By correcting the received signal data corresponding to the distance between the occupant and the dashboard based on the displacement current flowing, by comparing the corrected threshold data and the received signal data, The crew and the dashboard And controls to determine the appropriateness of separation situation with.

Further, in a fifth aspect of the present invention, the first antenna electrode is arranged in the seat portion inside the vehicle compartment, and the second antenna electrode is arranged in the dashboard portion facing the seat. , A weak electric field is generated between the first antenna electrode and the second antenna electrode, and a displacement current flowing to the second antenna electrode side is detected based on the transmission current to the first antenna electrode and the weak electric field. Then, it is calculated based on the data corresponding to these currents to determine the suitability of the separation condition between the occupant and the dashboard, and the data based on this determination result is transmitted 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.

[0029]

BEST MODE FOR CARRYING OUT THE INVENTION Next, an embodiment of an occupant detection system according to the present invention will be described with reference to FIGS. Incidentally, the basic principle of the present invention is basically to utilize the disturbance of the weak electric field generated around the antenna electrode similarly to the above-mentioned prior art, and specifically, the sheet and the dashboard are used. A weak electric field is generated between a pair of antenna electrodes placed in the antenna, and the displacement current flowing in the antenna electrode on the receiving side and the transmission supplied to the antenna electrode on the transmitting side are caused by the electrical characteristics of the object located between these antenna electrodes. The suitability of the distance between the occupant and the dashboard is determined based on the electric current. The same parts as those in the prior art shown in FIGS. 10 to 14 are designated by the same reference numerals, and the detailed description thereof is omitted. To do.

FIG. 1 shows a seat of a passenger seat according to the present invention, and this seat 1B is mainly composed of a seat portion 1a and a backrest portion 1b. This sheet 1B is
For example, a seat fixed to a base 2 that can slide back and forth.
The toft frame 3, the cushion member 4 arranged on the upper portion of the seat frame 3, the first antenna electrode 5 arranged along the surface of the cushion member 4, and the first antenna electrode 5
And an exterior material 6 arranged so as to cover the. The first antenna electrode 5 is preferably arranged along the surface of the cushion material 4 and over substantially the entire seating portion 1a. Further, the first antenna electrode 5 can be arranged outside the exterior material 6 as well as inside.

In particular, the first antenna electrode 5 is formed of a conductive cloth in consideration of the sitting comfort of the occupant P.
For example, a thread-like metal may be woven into the sheet cloth surface, a conductive paint may be applied to the cloth surface, or a metal plate may be arranged. The first antenna electrode 5 is arranged over a large area of the seating portion 1a of the seat 1B, and a part of the first antenna electrode 5 is connected to a control unit described later. It should be noted that this control unit is arranged in the sheet 1B, for example, the sheet frame portion to shorten the connection harness with the first antenna electrode 5, or to extend a part of the first antenna electrode 5. The presence may be omitted.

On the other hand, a dash board DB is installed on the front side facing the seat 1B, and the second antenna electrode 7 is installed in the dash board portion facing the seat 1B.
Are arranged. The second antenna electrode 7 is constructed in the same manner as the first antenna electrode 5 described above and is attached to the dashboard portion. For example, the first antenna electrode is formed on the resin material forming the dashboard DB. The electrode having the same structure as that of 5 is embedded, insert-molded, or only the dashboard portion corresponding to the antenna arrangement portion is
The resin material may be formed of a conductive resin material in which conductive powder is mixed and dispersed, or may be coated with a conductive paint. In particular, the second antenna electrode 7 is arranged in the dash board portion so that the facing area with at least a part of the occupant P approaching the dash board DB due to a collision or the like, for example, the head (particularly the face) becomes as large as possible. It is arranged.

In FIG. 2, the occupant detection system is a seat.
Sheet 1B and the first antenna electrode 5 and sheet 1
The second antenna electrode 7 arranged in the dashboard portion facing B, an oscillator circuit 10 for generating a high frequency low voltage having a frequency of about 100 KHz and a voltage of about 6 to 12 V, and the oscillator circuit 10 to the first Current detection circuit 11 for detecting the transmission current (transmission signal) Tx supplied to the antenna electrode 5 and the current having the function of converting the displacement current (reception signal) Rx flowing on the second antenna electrode side into a voltage and amplifying it. A voltage conversion circuit 13, a filter circuit 14 having a bandpass function, an amplification circuit 15, a control circuit 17 including an MPU, and an airbag device 18. The control unit described above is configured by a circuit excluding the airbag device 18, for example.

In this system, an oscillation circuit 10 is connected to a first antenna electrode 5 as a transmission electrode via a current detection circuit 11. This current detection circuit 11
Is an impedance element such as a resistor 11a and a resistor 11a, which are connected in series to the circuit and convert a transmission current flowing from the oscillation circuit 10 to the first antenna electrode side into a voltage.
And an amplifier 11b for amplifying the terminal voltage of the control circuit 17 and the output signal thereof is taken into the control circuit 17. still,
The output signal can also be taken into the control circuit 17 via, for example, a filter circuit. The current / voltage conversion circuit 13 connected to the second antenna electrode 7 serving as a receiving electrode is an impedance element such as a resistor 13 for converting a displacement current flowing on the second antenna electrode side into a voltage.
a and an amplifier 13b that amplifies the converted voltage, and its output signal is taken into the control circuit 17 via the filter circuit 14 and the amplifier circuit 15.

The system thus configured operates as follows. First, in a state where the occupant P is seated in the seat 1B, the oscillation circuit 10 is attached to the first antenna electrode 5.
When a high frequency low voltage is applied from the above through the current detection circuit 11, a weak electric field is generated between the first antenna electrode 5 and the second antenna electrode 7. Then, the transmission current Tx flows through the first antenna electrode 5, and the displacement current Rx according to the separation distance between the occupant P and the second antenna electrode 7 flows along the second antenna electrode side. Of these currents, the transmission current Tx is converted into a voltage by the resistor 11a, amplified by the amplifier 11b, and output to the control circuit 17. In the control circuit 17, this output signal is A / D converted and then stored in the memory as transmission signal data. On the other hand, the displacement current Rx is converted into a voltage by the resistor 13a, amplified by the amplifier 13b, and then output to the filter circuit 14. In this filter circuit 14, for example, a signal of about 100 KHz is band-passed, unnecessary noise components are removed, and the signal is output to the amplifier circuit 15. The output signal of the amplifier circuit 15 is output to the control circuit 17. In the control circuit 17, the amplifier circuit 1
After the output signal from 5 is A / D converted, the transmission signal data
It is stored in the memory as data (distance data).

On the other hand, when the distance d between the occupant P and the dashboard DB (that is, the second antenna electrode 7) has reached the allowable limit, for example, about 20 cm, the control circuit 17 has the second distance. The threshold value (threshold distance data) corresponding to the average displacement current flowing on the antenna electrode side of is stored. Therefore, when the output signal of the amplifier circuit 15 which is actually related to the displacement current detected on the second antenna electrode side is taken into the control circuit 17 as the distance data, it is stored in the control circuit 17 in advance. The appropriateness of the separation distance between the occupant P and the dashboard DB is determined by comparing (calculating) the value distance data and the actual distance data.

Therefore, if the reception distance data is larger than the threshold distance data, it is determined that the actual separation distance d between the occupant P and the dashboard DB is allowed, for example, 20 cm or more. Therefore, the airbag device 18
Is set so that the airbag can be deployed by a transmission signal from the control circuit 17. Conversely, if the distance data is smaller than the threshold data, the occupant P and the dashboard are
The actual separation distance d from the DB is not allowed, for example, 2
Since it is determined that the height is 0 cm or less, the airbag device 18 receives the transmission signal from the control circuit 17,
The airbag is set so that it cannot be deployed. That is, the transmission signal from the control circuit 17 is input to the control circuit CC of the airbag device 18, and in the latter case, the gate signal is set not to be supplied to the semiconductor switching element SW2 on the passenger side in the event of a vehicle collision. To be done. A gate signal is supplied to the semiconductor switching element SW1 on the driver's seat side. In the former case, the semiconductor switching elements SW1 and SW2 are set so that a gate signal is supplied.

By the way, depending on the occupant P, an appropriate cushion or the like is laid on the seat 1B to adjust the seating posture so that the operability of the vehicle is optimized. There is. In this case, since the cushion or the like has a smaller dielectric constant than a human, the transmission current Tx flowing to the first antenna electrode side is lowered in level, and the displacement current Rx flowing to the second antenna electrode side is also seated by the occupant P. However, it will decrease. In such a state, even if the separation distance d between the occupant P and the dashboard DB is not allowed, for example, 20 cm or less, the separation distance recognized based on the displacement current flowing to the second antenna electrode side is 20 cm. It is judged to be within the above safety zone. Therefore, there is a concern that the airbag of the airbag device 18 may be undesirably deployed.

In such a case, since the level reduction of the transmission current Tx is detected by the output signal from the current detection circuit 11, the level correction or threshold of the reception signal is made by using the transmission signal Tx and the reception signal Rx. The control circuit 17 corrects the value data. For example, the correction of the reception distance data (correction of the separation distance d) is performed based on d = K.Rx / Tx. Here, K is a correction coefficient. Therefore, the separation distance calculated based on the displacement current is approximated to the actual separation distance d by the correction by the above equation, and the occupant P and the dashboard DB are compared with the threshold distance data. The appropriateness of the separation situation of the
The airbag of the airbag device 18 can be reliably set to either deployable or undeployable.

Next, the processing flow of this occupant detection system.
Will be described with reference to FIGS. First, as shown in FIG. 3, the ignition switch is turned on and started. Initialization is performed in step S1, and the process proceeds to step S2. In step S2, an initial diagnosis of the communication system between the control circuit 17 and the airbag device 18 is performed. In step S3, it is determined whether the engine has started. If it is determined that the engine has started, the process proceeds to step S4. If it is determined that the start is not started, the process returns. In step S4, the displacement current flowing to the second antenna electrode side is related to the current flowing to the first antenna electrode side and the weak electric field generated between the first antenna electrode 5 and the second antenna electrode 7 based on the weak electric field. Signal data to be received is received. Then, in step S5, the actual separation distance d between the occupant P and the dashboard DB is determined based on the captured data. Further, in step S6, the airbag device (S
SRS communication is performed with the RS) 18. Step S
When step 6 ends, the process returns to step S4 again, and
The processing from 4 to step S6 is repeated. Incidentally, step S3 can be omitted.

The initial diagnosis in FIG. 3 is performed as shown in FIG. 4, for example. First, in step SA1, a fixed data
From the control circuit 17 to the control circuit C of the airbag device 18.
Send to C. In step SA2, the airbag device 18
Receives transmission data from. And step SA3
Then, it is determined whether or not the fixed data transmitted from the control circuit 17 to the airbag device 18 and the received data from the airbag device 18 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, fixed data is transmitted from the airbag device 18 to the control circuit 17, and the transmission data from the control circuit 17 is judged by the control circuit CC of the airbag device 18 for the matching. You may do it.

The occupant determination (distance determination) in FIG. 3 is performed as shown in FIG. 5, for example. First, step SB1
When a rug such as a cushion is interposed between the occupant P and the seat seating portion, the displacement current (reception signal Rx)
The calculated separation distance calculated based on
K · Rx / Tx) is corrected to approximate the actual separation distance d, and the process proceeds to step SB2. Step SB
At 2, it is determined whether the corrected distance data (d) is smaller than the threshold distance data stored in advance in the control circuit 17. If it is determined that the corrected distance data (d) is smaller than the threshold distance data, step SB3.
Then, the OFF data for preventing the airbag of the airbag device 18 from being deployed is set, and the processing flow is continued. If it is determined that the distance data (d) corrected in step SB2 is not smaller (larger) than the threshold value data, the process proceeds to step SB4 to deploy the airbag of the airbag device 18. ON data is set and the SRS data communication flow is continued.

The SRS data communication in FIG. 3 is performed as shown in FIG. 6, for example. First, in step SC1, the occupant detection unit side (control circuit 17) moves from the occupant detection unit side (control circuit CC) to the airbag device 18 (control circuit CC) so that the airbag of the airbag device 18 can be inflated or undeployed. -OFF or OFF data and check data are transmitted. At step SC2, OK data for ON data or OFF data from the airbag device side is received.
After receiving data or NG data and check data, the process proceeds to step SC3. At step SD3, the ON / OFF data transmitted from the occupant detection unit side to the airbag device side.
It is again determined whether or not the data and check data have been returned to the occupant detection unit side from the airbag device side in a normal state. If it is judged 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 SC4, 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, then the processing advances to step SC5, where the fail-safe timer is reached.
The timer is counted, and the processing flow is continued.

On the other hand, in step SD1, the airbag device side (control circuit CC) is on the occupant detection unit side (control circuit 1).
From 7), ON data or OFF data and check data for making the airbag of the airbag device 18 in a deployable state or an undeployable state are received. Then, in step SD2, the reception data is checked to determine whether or not the reception data can be normally received. In either case, the process proceeds to step SD3
K data or NG data and check data are transmitted to the occupant detection unit side. If it is determined in step SD2 that there is no abnormality in the communication system, the OK data in step SD3
After the data transmission step, the process proceeds to step SD4. In step SD4, 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. When it is determined in step SD2 that the communication system is abnormal, the process proceeds to step SD5 after the NG data transmitting step of step SD3. At step SD5, it is judged if the fail-safe timer has become 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 SD6, the fail-safe timer is counted, and the processing flow is continued.

According to this embodiment, the first antenna electrode 5 is provided on the front surface side of the sheet 1B, and the second antenna electrode 7 is provided on the dashboard portion DB facing the sheet 1B. Since the weak electric field is generated by the application of the high frequency and low voltage between them, the second
The occupant P seated in seat 1B on the antenna electrode side of
, A displacement current corresponding to the attitude with respect to the dashboard DB (second antenna electrode 7) flows. Therefore, the appropriateness of the actual separation distance between the occupant P and the dashboard DB can be easily detected based on the magnitude of the displacement current.

In particular, when a cushion or other rug is interposed between the occupant P and the seat seat, the control circuit 17 calculates the displacement current (received signal Rx) based on the calculated value. Is the correction formula (d = K · Rx /
The corrected distance data (d) is compared with the threshold distance data previously stored in the control circuit 17 in order to be corrected by Tx) so as to approximate the actual distance d. , The suitability of the actual separation distance between the occupant P and the dashboard DB can be accurately determined.

Further, a rug such as a cushion is not interposed between the occupant P and the seat seat portion, and the transmission signal T is simply transmitted.
If x is down for some reason,
The calculated separation distance calculated based on the received signal Rx can be corrected so as to approximate the actual separation distance d by the above-described correction formula, and the child seat 1A can be corrected.
Can be similarly applied even when is arranged in the state of RFIS.

In addition, the airbag of the airbag device 18 is set to either the deployable state or the undeployable state based on the suitability judgment of the actual separation distance between the occupant P and the dashboard DB. To be done. For example, when it is determined that the separation distance between the occupant P and the dashboard DB is an unacceptable distance, the airbag of the airbag device 18 is set to a non-deployable state. Therefore, even if a car collides, the airbag will not be deployed,
It is possible to prevent the occupant P from being secondarily damaged by the airbag.

Further, the second antenna electrode 7 has the largest possible facing area to the dashboard part DB and a part of the occupant P approaching the dashboard DB due to a collision of an automobile, for example, the face (head). The occupant is used as a kind of antenna and
The level change of the displacement current flowing to the antenna electrode side of can be accurately received. Therefore, the crew P and the dashboard DB
It is possible to accurately detect the actual separation distance from.

The present invention is not limited to the above-mentioned embodiment at all, and for example, the shape of the antenna electrodes arranged in the sheet and the dashboard is not only rectangular but also circular, elliptical or square. It can also be formed in a polygonal shape except. First
The antenna electrode of is placed on the entire seat of the seat,
It can be arranged in a smaller area than the seating portion.
The output frequency of the oscillator circuit can be set to a value other than 100 KHz depending on the situation such as the vehicle interior. Further, the airbag device may use a mechanical sensor in addition to the electronic acceleration sensor.

[0051]

As described above, according to the present invention, the first antenna electrode is arranged on the sheet, and the second antenna electrode is arranged on the dashboard portion facing the sheet. Since a weak electric field is generated by applying a high frequency and low voltage between them, the dashboard (of the second seat) of the occupant seated in the seat is located on the second antenna electrode side. A displacement current flows according to the posture with respect to the antenna electrode). Therefore, the appropriateness of the actual separation distance between the occupant and the dashboard can be easily detected based on the magnitude of the displacement current.

In particular, when a rug such as a cushion is interposed between the occupant and the seat seat, the calculated separation distance calculated based on the received signal Rx in the control circuit is corrected. The corrected distance data and the threshold distance data stored in advance in the control circuit are corrected by the equation (d = K · Rx / Tx) so as to approximate the actual distance d. By comparing with, the appropriateness of the actual separation distance between the occupant and the dashboard can be accurately determined. Therefore, the airbag of the airbag device can be set to either the deployable state or the undeployable state based on the determination result, and the secondary damage from the airbag is avoided by the undesired deployment of the airbag. it can.

Further, a cushion or other rug is not interposed between the occupant and the seat occupant, and the level of the transmitted signal is simply lowered for some reason, or if the seat is a child seat, for example. Even in the case of being arranged in the state of RFIS, the calculated separation distance calculated based on the received signal can be corrected so as to approximate to the actual separation distance by the above-mentioned correction formula, and the airbag device Can be operated properly.

Further, the second antenna electrode is attached to the dashboard portion by a collision of an automobile or the like.
Since the opposing area to a part of the occupant approaching the door is arranged to be as large as possible, the occupant can be used as a kind of antenna to accurately receive the level change of the displacement current flowing to the second antenna electrode side. Therefore, the actual separation distance between the occupant and the dashboard can be accurately detected.

[Brief description of drawings]

FIG. 1 is a diagram showing a vehicle interior portion of an occupant detection system according to the present invention, in which FIG. 1 (a) is a diagram showing an arrangement state of first and second antenna electrodes, and FIG. -A sectional view of the main part of g.

FIG. 2 is a circuit block diagram of an occupant detection system according to the present invention.

FIG. 3 is a flow chart for detecting an occupant according to the present invention.

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

FIG. 5 is a flowchart of occupant determination (distance determination) shown in FIG.

FIG. 6 is a flowchart of the SRS communication shown in FIG.

FIG. 7 is a circuit block diagram of an airbag device according to a conventional example.

8A and 8B are views showing various seating patterns, in which FIG. 8A shows a state in which an adult occupant is seated in the seat, and FIG. 8B shows an RFIS state. Figure, (c)
Shows a state of FFCS.

FIG. 9 is a circuit block diagram of an improved airbag device according to a conventional example.

10A and 10B are views for explaining the basic operation of the occupant detection system according to the prior art, which is a premise of the present invention, in which FIG. 10A is a diagram showing an electric field distribution between electrodes, and FIG. FIG. 4 is a diagram showing an electric field distribution when an object is present between electrodes.

FIG. 11 is a perspective view of a seat of an occupant detection system according to the prior art.

FIG. 12 is a circuit block diagram of an occupant detection system according to the prior art.

13 is a specific circuit block diagram of FIG.

FIG. 14 is a detailed circuit block diagram of the airbag device shown in FIG.

FIG. 15 is a schematic view showing a state in which a passenger is seated in a passenger seat of a conventional automobile.

[Explanation of symbols]

1B sheet 1a Seating section 1b Backrest 2 bases 3 sheet frames 4 cushion material 5 First antenna electrode 6 Exterior materials 7 Second antenna electrode 10 oscillator circuit 11 Current detection circuit 13 Current / voltage conversion circuit 14 Filter circuit 15 Amplification circuit 17 Control circuit 18 Airbag device DB dashboard SS1, SS2 safing sensor SQ1, SQ2 squib SW1, SW2 Semiconductor switching element CC control circuit GS Electronic acceleration sensor

Continuation of the front page (56) Reference JP-A-8-225058 (JP, A) JP-A-7-165011 (JP, A) JP-A-1-12948 (JP, A) JP-A-7-285364 (JP , A) JP-A-1-44356 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) B60N 5/00 B60R 21/32

Claims (5)

(57) [Claims] 1. A first antenna electrode disposed in a seat portion of a vehicle compartment, a second antenna electrode disposed in a dashboard portion facing the seat, a first antenna electrode and a first antenna electrode. Oscillation circuit for generating a weak electric field between the second antenna electrode, a current detection circuit for detecting a transmission current flowing from the oscillation circuit to the first antenna electrode, the first antenna electrode and the second antenna electrode A displacement current is detected based on the weak electric field generated between the current and voltage conversion circuit that converts it into a voltage, and the seat is seated based on the output signals of the current detection circuit and current / voltage conversion circuit. An occupant detection system, comprising: a control circuit that determines whether or not a separation distance between an occupant who is operating and a dashboard is appropriate. 2. A first antenna electrode arranged in a seat portion of a vehicle compartment, a second antenna electrode arranged in a dashboard portion facing the seat, a first antenna electrode and a first antenna electrode. Oscillation circuit for generating a weak electric field between the second antenna electrode, a current detection circuit for detecting a transmission current flowing from the oscillation circuit to the first antenna electrode, the first antenna electrode and the second antenna electrode A displacement current is detected based on the weak electric field generated between the current and voltage conversion circuit that converts it into a voltage, and the seat is seated based on the output signals of the current detection circuit and current / voltage conversion circuit. A control circuit for determining whether or not the separation distance between the occupant and the like and the dashboard is appropriate, and an airbag device having a function of deploying an airbag based on a collision, based on the determination result of the control circuit De An occupant detection system characterized by transmitting the data to the airbag device and setting the airbag of the airbag device to either a deployable state or an undeployable state. 3. The first antenna electrode is arranged at a seating portion of the seat, and the second antenna electrode is arranged at a dashboard portion and at least a part of an occupant who approaches the dashboard due to a collision or the like. The occupant detection system according to claim 1 or 2, wherein the occupant detection system is arranged so that the facing area is as large as possible. 4. The control circuit has threshold data corresponding to an allowable separation distance between an occupant or the like and a dashboard in advance, and has a level of a transmission current to the first antenna electrode. When the fluctuation occurs, the received signal data corresponding to the distance between the occupant and the dashboard based on the threshold data or the displacement current flowing on the second antenna electrode side based on the fluctuation is displayed. Compensation and comparing the corrected threshold value data with the received signal data to perform control so as to determine the suitability of the separation condition between the occupant and the dashboard. The occupant detection system according to Item 1 or 2. 5. A first antenna electrode is provided at a seat portion inside a vehicle compartment, and a second antenna electrode is provided at a dashboard portion facing the seat.
Antenna electrodes are respectively arranged, a weak electric field is generated between the first antenna electrode and the second antenna electrode, and the second antenna electrode is generated based on the transmission current to the first antenna electrode and the weak electric field. The displacement current flowing to the side is detected, and the arithmetic processing is performed based on the data corresponding to these currents to determine the suitability of the separation condition between the occupant and the dashboard and the data based on this determination result. An occupant detection method comprising transmitting to an airbag device and setting the airbag of the airbag device to either a deployable state or an undeployable state.