JP2001264194A - Sitting detection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sitting detection device which can decide whether or not a person sits comfortably even if air is humid without making complicated algorithm and the management of sheet manufacture for maintaining detection precision. SOLUTION: In antenna electrode is buried in a sheet and an electric field output part which supplies radio wave radiation power to the antenna electrode and a data processor which records and processes the output value from the electric field output part are provided; and the data processor detects variation in the impedance of an electrostatic capacity sensor composed of the antenna electrode and a grounding part when a person sits on the sheet, so that this sitting detection device detects the sitting state of the person. This sitting detection device is characterized by that a 1st output value that the electrostatic capacity sensor generates when the person is not sitting is detected and a 2nd output value of the electrostatic capacity sensor when the person sits is corrected with the 1st output value.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a seating detecting device for detecting whether a person is sitting on a seat, and more particularly to a seating detecting device using a capacitance sensor.

[0002]

2. Description of the Related Art FIG. 5 and FIG. 6 show a seating detection device using a conventional capacitance sensor for detecting a seated state of a person.
This will be described with reference to FIG. A conventional seating detection device using a capacitance sensor includes a plurality of antenna poles 1 embedded in the center of a seat back STB of a seat ST as shown in FIG.
01a to 101f (six in the figure) and the antenna pole 1
The main part is composed of an electric field output unit (not shown) for generating an electric field around 01a to 101f and the data processing device 102 corresponding to the antenna electrodes 101a to 101f. Here, the reason for using the capacitance sensor is that it has excellent output stability among non-contact type sensors, and has a feature of being able to measure minute displacement stably with high accuracy. This is because 101f can be made ultra-thin (1 mm or less in thickness) or can be processed freely to reduce its size, so that even if it is embedded in a sheet, there is a merit that a person does not feel uncomfortable.

[0003] The operation of the conventional seating detection device constructed from these will be described. When a sine wave of, for example, 120 kHz is oscillated from the high-frequency oscillation circuit of the electric field output unit, a radio wave is emitted from the antenna poles 101a to 101f into space. When no person is seated on the seat, the value of the current output to the data processing device 102 that is generated in response to radio waves radiated from the plurality of antenna electrodes 101a to 101f is:
Since almost no current flows from the electric field output section to the outside of the system, the current value becomes extremely large according to the distance between the antenna electrodes 101a to 101f and the ground section GND and the dielectric constant of air. As a result, the voltage difference generated before and after the current monitor resistor also increases. On the other hand, when a person (not shown) having a higher dielectric constant than air sits on the seat, the antennas 101a to 101f and the distance to the person and the area of the human body facing the antenna electrodes 101a to 101f depend on the antenna. As a result, the impedance between the electrodes 101a to 101f and the ground portion GND changes, and a large current flows from the electric field output portion to outside the system via the human body.
A small current flows on the 02 side. Accordingly, the six antenna electrodes 101 when a person is seated and when a person is not seated
By analyzing the output patterns from a to 101f, it is possible to detect whether or not a person is seated.
If the data processing device 102 determines that a person is seated, an electric signal is transmitted via the transmitter 103 to a receiver (not shown).

[0004]

However, in the conventional seating detection device using a capacitance sensor, the capacitance sensor formed by the antenna electrodes 101a to 101f and the ground portion GND reacts with the dielectric. Therefore, it is susceptible to, for example, moisture. That is, as shown in FIG. 5, when a person is not seated, there should be no output of the capacitance sensor. However, if there is moisture, a sensor output is output even if the person is not seated, When a person is seated on the seat, the sensor output is superimposed on the sensor output when the seat is not seated and is greatly output, so that the algorithm and the management in manufacturing the seat are complicated in order to maintain the detection accuracy.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and does not complicate the algorithm and the management of sheet production in order to maintain the detection accuracy. An object is to provide a seating detection device that can determine whether a person is seated.

[0006]

According to a first aspect of the present invention, there is provided a seating detecting apparatus for solving the above-mentioned problems. Providing an electric field output unit for supplying radio wave radiated power to the electrodes and a data processing device for recording and processing the output value from the electric field output unit, formed from the antenna electrode and the grounding unit when a person sits on the seat A change in the impedance of the capacitance sensor is detected by the data processing device, and the first output of the capacitance sensor when a person is not seated is detected by a seating detection device that detects a seated state of a person. The first output value is detected, and the second output value of the capacitance sensor when a person is seated is corrected based on the first output value.

As described above, the first output value of the capacitance sensor when the person is not seated is detected, and the second output of the capacitance sensor when the person is seated is detected based on the first output value. By correcting the output value, it is possible to accurately detect whether or not a person is seated.

The gist of the invention described in claim 2 of the present invention for solving the above-mentioned problems is to embed an antenna electrode in a seat and to apply radio wave radiation power to the antenna electrode. An electric field output unit for supplying and a data processing device for recording and processing an output value from the electric field output unit are provided, and a capacitance sensor formed from the antenna electrode and a grounding unit when a person sits on the seat In the seating detection device for detecting a change in the impedance of the data processing device by the data processing device and detecting a seated state of a person, a non-contact type sensor capable of detecting a person separately from the capacitance sensor is provided, and at least one of the sensors is provided. Is configured to detect a seated state of a person.

As described above, since the detecting means for detecting the seated state of the person is constituted by the capacitance sensor and the non-contact type sensor different from the capacitance sensor, only the sensor output of the capacitance sensor is used. Even when it is difficult to determine whether or not a person is seated, the seated state of the person can be reliably detected.

[0010]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a vehicle seat occupant detecting apparatus according to the present invention. FIG. 1 is an overall block diagram of a first embodiment when a vehicle occupant detection device and an airbag control device of the present invention are used in combination, and FIG. 2A is a vehicle occupant detection of the vehicle of the present invention. FIG. 2B is a schematic diagram showing a main configuration of the device, FIG. 2B is an explanatory diagram for analyzing output data of a vehicle occupant detection device of the present invention, and FIG. FIG. 4 is an explanatory diagram of a case where the output of the capacitance sensor is corrected and output, and FIG. 4 is an overall block diagram of a second embodiment when a vehicle occupant detection device and an airbag control device of the present invention are used in combination. It is.

First, with reference to FIG. 1, an embodiment in which the seating detection device according to the present invention is used as an occupant seating detection device of a vehicle will be described. The vehicle occupant sitting detection device 1 of the present invention has an electric field output unit 2 for generating high-frequency power, and six antenna electrodes 3a to 3f for radiating radio waves by radio wave radiation power supplied from the electric field output unit 2. A capacitance sensor formed of a sensor unit 3 and a grounding unit (vehicle floor) GND, and an output value (current value) from the electric field output unit 2 recorded and corrected, and a set value inputted in advance. The data processing device 4 that determines whether or not the occupant is seated by performing a comparison operation process constitutes a main part.

The airbag control device 5 includes an airbag device control unit 6, a collision G detection unit 7, and an inflator drive circuit unit 8. The airbag device control unit 6 is a control device having a CPU, a memory, an I / O port, an interrupt circuit, and the like (not shown). The collision G detection unit 7 detects the impact force of the vehicle using the acceleration sensor. If the detected impact force is a strong impact force equal to or greater than a predetermined value, an electric signal is output to the airbag device control unit 6. The airbag control device 5 configured as described above controls the airbag device based on the electric output signal from the data processing device 4 and the electric output signal from the collision G detection unit 7 that detects the impact force at the time of collision with an acceleration sensor. When both of these electric output signals exceed the respective set values when input to the unit 6, the airbag device control unit 6 instructs the inflator drive circuit unit 8 to drive the inflator drive circuit unit 8 so as to drive the inflator drive circuit unit 8. A signal is output. When an electric output signal is input from the airbag device control unit 6 to the inflator drive circuit unit 8, the inflator is activated to generate nitrogen gas.
The airbag inflates in 03 seconds.

As shown in FIG. 2A, the electric field output section 2 includes a high-frequency oscillation circuit 2a having one end grounded, a current monitor resistor 2b, and respective antenna electrodes 3a to 3d at the exit side of the current monitor resistor 2b. The main part is composed of a shield wire 2e connected to the shield wire 3f and an amplifier 2c for supplying a necessary current to the shield wire 2e. High frequency oscillation circuit 2
One end of a is grounded, and the other end is connected to one end of the monitor resistor 2b. On the other hand, one of the two branched lines on the other end side of the current monitor resistor 2b is connected to the respective antenna electrodes 3a to 3f via the shield line 2e and to the data processing device 4 via the amplifier 2d. Connected. The amplifier 2c branches a part of the current flowing out of the current monitor resistor 2b in order to shield the electric wiring so that the radio wave radiation power supplied to the antenna electrodes 3a to 3f is not affected by an external magnetic field or the like. , For amplifying the same and supplying it as a shield current to the shield line 2e.

The capacitance sensor has six antenna electrodes 3a that radiate a high frequency (sine wave) generated by the electric field output unit 2.
Sensor unit 3 having ｆ3f and grounding unit (body floor) GND
And formed from Six antenna electrodes 3a to 3f are buried in the center of the seat back of the vehicle, and receive the radio wave radiation power supplied from the electric field output unit 2 to radiate radio waves into space.

The data processing device 4 is a device for recording, correcting and calculating output values when an occupant is seated and not seated on a vehicle seat. As shown in FIG. 3, the sensor output value when the occupant is seated is corrected using the sensor output value when the occupant is not seated (normally no output) as a reference value (blank value). As a result of the correction, if it is determined that the occupant is seated, the data processing device 4 outputs an electric signal to the airbag device control unit 6 of the airbag control device 5 (see FIG. 1). On the other hand, when it is determined that the occupant is not seated, no electric signal is output.

The operation of the occupant seating detection system 1 for a vehicle constructed as described above will be described with reference to FIG. When a sine wave of, for example, 120 kHz is oscillated from the high-frequency oscillation circuit 2a of the electric field output unit 2, the output current I
It is converted to a voltage at b. When the occupant is not seated on the seat, as shown in FIG. 2B, the output current Ia to the data processing device 4 which is generated in response to radio waves radiated from the plurality of antenna electrodes 3a to 3f is output. Since almost no current flows from the electric field output unit 2 to the outside of the system,
The current value becomes very large according to the distance between a to 3f and the ground portion GND and the dielectric constant of air. As a result, the voltage difference generated before and after the current monitor resistor 2b increases, and the voltage output of the amplifier 2d increases.
On the other hand, when an occupant having a dielectric constant higher than that of air is seated on the seat, the antenna electrodes 3a to 3f depend on the distance between the antenna electrodes 3a to 3f and the occupant, and the area of the human body facing the antenna electrodes 3a to 3f. As a result, a large current flows from the electric field output unit 2 through the human body to the outside of the system, so that a small current Ib flows on the data processing device 4 side. As a result, the voltage difference generated before and after the current monitor resistor 2b is reduced, and
The voltage output of the amplifier 2d decreases. Therefore, by analyzing the output patterns from the six antenna electrodes 3a to 3f when the occupant is seated and when the occupant is not seated, it is possible to detect whether or not the occupant is seated.
As a method of analyzing the output pattern, as shown in FIG. 2B, full-wave rectification is performed on each output current (or voltage) when the occupant, which is a dielectric, is seated and when the occupant is not seated. By calculating the average output value and comparing the average output value with a predetermined set value, it can be detected whether or not the occupant is seated.

Next, a description will be given of a second embodiment in which the vehicle occupant detection device and the airbag control device of the present invention are used in combination with reference to FIG. The only difference between the second embodiment and the first embodiment is whether a non-contact occupant detection sensor is provided separately from the capacitance sensor. Therefore, the description of the overall configuration and operation is substantially the same as that of the first embodiment, and will not be repeated.
Therefore, only the configuration and operation of the non-contact sensor used together with the capacitance sensor will be described. Non-contact sensors
The ultrasonic sensor 9. The ultrasonic sensor 9 is preferable because the distance measurement range is wide and the measurement can be performed without being affected by the electrical characteristics such as the transparency and color of the measurement target and the dielectric constant. As the non-contact type sensor, for example, a pyroelectric infrared sensor (an infrared detecting sensor generated from a human body) other than the ultrasonic sensor (distance measuring sensor) 9 can be used. However, the optical sensor tends to cause a distance measurement error due to a difference in color. As a measurement principle of the ultrasonic sensor 9, a pulse echo method is used. In the pulse echo method, the distance to the measurement target can be obtained from the delay time until the ultrasonic wave is transmitted after being pulse-modulated and reflected by the measurement target.

Next, the operation of the second embodiment using both the capacitance sensor and the ultrasonic sensor 9 will be described. The capacitance sensor alone can detect the sitting posture and the physique of the occupant. However, if the occupant's seated posture is a lean-back posture or the like, the detection accuracy is reduced. Therefore, by using the output circuit of the ultrasonic sensor 9 provided separately from the capacitance sensor, it is possible to reliably detect whether or not an occupant who is difficult to detect by the capacitance sensor alone is seated. It can also detect where the occupant of the physique is sitting.

It should be noted that the seating detection device of the present invention can be variously modified and implemented as needed without departing from the technical scope of the present invention. For example, as an application example of the seating detection device, in the case of a fire in a customer center such as a movie theater, an opera theater, and Kabukiza, when the customer is guided to an emergency exit, a direction to evacuate the customer from the output of the seating detection device And can identify the location of the emergency exit. In addition, when the user fastens the seat belt at the time of takeoff and landing of the aircraft, the seating state of the customer can be confirmed.

[0020]

As is clear from the above configuration and operation, (1) According to the first aspect of the present invention, as described in detail in the first embodiment of the present invention, for example, when the occupant is not seated The first output value of the capacitance sensor is detected, and the second output value of the capacitance sensor when the occupant is seated is corrected based on the first output value, so that the occupant is seated. Can be accurately detected. (2) According to the second aspect of the present invention, as described in detail in the first embodiment of the present invention, for example, the detecting means for detecting the sitting state of the occupant is provided separately from the capacitance sensor and the capacitance sensor. Therefore, even if it is difficult to detect whether or not the occupant is seated using only the sensor output value of the capacitance sensor, the seated state of the occupant can be reliably detected.

[Brief description of the drawings]

FIG. 1 is an overall block diagram of a first embodiment when a vehicle occupant detection device and an airbag control device of the present invention are used in combination.

FIG. 2A is a schematic diagram illustrating a main configuration of a vehicle occupant sitting detection device of the present invention. (B) It is explanatory drawing in the case of analyzing the output data of the vehicle occupant sitting detection apparatus of this invention.

FIG. 3 is an explanatory diagram illustrating a case where an output value of a capacitance sensor of the vehicle occupant detection device of the present invention is corrected and output.

FIG. 4 is an overall block diagram of a second embodiment when a vehicle occupant detection device and an airbag control device of the present invention are used in combination.

FIG. 5 is a diagram for explaining a problem of the conventional seating detection device.

FIG. 6 is a view showing an embodiment in which an antenna electrode is embedded in a seat back of a seat according to a conventional seating detection device.

[Description of Signs] 1 Occupant seat detection device 2 Electric field output unit 3 Sensor unit 3a to 3f Antenna electrode 4 Data processing device 5 Airbag control device 6 Airbag device control unit 7 Collision G detection unit 8 Inflator drive circuit unit 9 Ultrasonic wave Sensor GND Ground

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Koichi Uechi 1-4-1 Chuo, Wako-shi, Saitama Prefecture Inside Honda R & D Co., Ltd. (72) Inventor Tsutomu Fukui 1-4-1 Chuo, Wako-shi, Saitama Prefecture No. F-term in Honda R & D Co., Ltd. (reference) 2F051 AA01 AB06 AC01 AC07 BA07 BA08 3B087 DE00 DE08 3D054 EE10 EE34 EE60 FF17

Claims (2)

[Claims] An antenna electrode is embedded in a sheet, and an electric field output unit for supplying radio wave radiated power to the antenna electrode and a data processing device for recording and processing an output value from the electric field output unit are provided. A seating detection device that detects a change in impedance of a capacitance sensor formed from the antenna electrode and the ground portion when the user sits on the seat by the data processing device and detects a seating state of a person. A first output value of the capacitance sensor when not sitting is detected, and a second output value of the capacitance sensor when a person is seated is corrected based on the first output value. A seating detection device characterized in that the seating detection device is configured as follows. 2. An antenna electrode embedded in a sheet, an electric field output unit for supplying radio wave radiation power to the antenna electrode, and a data processing device for recording and processing an output value from the electric field output unit are provided. The data processing device detects a change in impedance of a capacitance sensor formed by the antenna electrode and the ground portion when the user sits on the seat, and detects a sitting state of a person. A seating detection device comprising a non-contact type sensor capable of detecting a person separately from a capacitance sensor, wherein at least one of the sensors detects a seating state of the person.