JP7188678B2 - Electrocardiographic detector for vehicle - Google Patents

Description

TECHNICAL FIELD The present invention relates to an electrocardiogram detection device for a vehicle, which is mounted on a vehicle and detects an electrocardiogram waveform of a driver.

A technique is known in which electrodes are provided on a steering wheel or a vehicle seat to detect an electrocardiographic waveform of an occupant.

For example, Patent Literature 1 discloses first, second, and third direct electrodes attached to a steering wheel of a vehicle for detecting the body potential of a driver, and a seat of the vehicle to detect the body potential of the vehicle without contact. Capacitively coupled electrodes for detecting a body potential of a driver, first voltage measuring means for measuring a voltage between the first and second direct electrodes, the third direct electrode and the capacitance. and a second voltage measuring means for measuring the voltage of the coupled electrode, and operating based on either or both of the measurement result of the first voltage measuring means and the measurement result of the second voltage measuring means. A vehicular electrocardiogram measuring device for measuring a person's electrocardiogram waveform has been proposed.

Japanese Unexamined Patent Application Publication No. 2011-24902

However, with the technique of Patent Document 1, it may be difficult to form a capacitor between the metal plate outside the body and the body depending on how the steering wheel is held, how the seat is sat, the thickness of the clothes, and the like. There is room for improvement in order to accurately measure the electrical signal of

SUMMARY OF THE INVENTION It is an object of the present invention to provide a vehicle electrocardiogram detecting apparatus capable of more accurately detecting electrical signals in a living body.

In order to achieve the above object, a first aspect includes a pair of steering electrodes provided on the steering wheel corresponding to the left and right hands of the driver, and a steering wheel for the vehicle below the position of the heart of the seated driver. A sheet electrode provided on a seat, a grounded ground electrode, a detector for detecting a differential voltage between two inputs, and an electrocardiographic waveform among the pair of steering electrodes, the seat electrode, and the ground electrode. a connection unit that selectively switches and connects two derivable electrodes as inputs of the detection unit.

According to the first aspect, the pair of steering electrodes are provided on the steering wheel corresponding to the right and left hands of the driver, and the seat electrodes are positioned on the vehicle seat below the position of the heart of the seated driver. and the ground electrode is grounded.

The detector detects a differential voltage between the two inputs. Then, in the connecting portion, two electrodes from among the pair of steering electrodes, the seat electrode, and the ground electrode, which are capable of deriving an electrocardiographic waveform, are selectively switched and connected as the input of the detecting portion. That is, since the combination of the inputs of the detection unit can be selectively switched by the connection unit, by switching the connection unit to a combination with a higher signal strength of the detection unit, the electric signal in the living body can be detected more accurately. becomes possible.

Two predetermined combinations of the pair of steering electrodes, seat electrodes, and ground electrodes are sequentially switched to select a combination in which the strength of the differential voltage detected by the detection unit is equal to or greater than a predetermined threshold value. may further include a control section for controlling the connecting section.

Further, an identification unit for identifying a driver is included, and the control unit learns the switching order for sequentially switching between two combinations from the control result of the control unit for each driver identified by the identification unit, and the identification result of the identification unit. The connection unit may be further controlled so as to switch sequentially in the switching order learned according to .

Also, the connecting portion is configured to sequentially switch between two predetermined combinations of the pair of the steering electrode, the seat electrode, and the ground electrode, and select the combination that maximizes the intensity of the differential voltage detected by the detecting portion. You may make it further include the control part which controls.

Further, a plurality of detection units may be included, and the connection unit may selectively switch and connect two of a pair of steering electrode, seat electrode, and ground electrode as inputs to each of the plurality of detection units.

As described above, according to the present invention, there is an effect that it is possible to provide a vehicular electrocardiographic detection apparatus capable of more accurately detecting electrical signals in a living body.

1 is a diagram showing a schematic configuration of a vehicle electrocardiographic detection apparatus according to a first embodiment; FIG. 1 is a block diagram showing the configuration of an electrocardiographic waveform generator; FIG. FIG. 4 is a diagram showing a combination of electrodes connected to input terminals of a differential amplifier in the vehicle electrocardiographic detector according to the first embodiment; FIG. 3 is a diagram showing an example of a waveform corresponding to an electrocardiographic waveform output from a differential amplifier; 4 is a flow chart showing a first example of the flow of processing performed by the control unit of the vehicle electrocardiographic detection apparatus according to the first embodiment; 7 is a flow chart showing a second example of the flow of processing performed by the control unit of the electrocardiographic detection device for vehicle according to the first embodiment; 9 is a flow chart showing a third example of the flow of processing performed by the control unit of the electrocardiographic detection device for vehicle according to the first embodiment; FIG. 10 is a diagram showing a schematic configuration of a vehicle electrocardiographic detection apparatus according to a second embodiment;

An example of a vehicle electrocardiographic detection apparatus according to an embodiment of the present invention will be described in detail below with reference to the drawings.

(First embodiment)
First, the vehicle electrocardiographic detection device 10 according to the first embodiment will be described. FIG. 1 is a diagram showing a schematic configuration of a vehicle electrocardiographic detection apparatus according to the present embodiment.

A vehicle electrocardiogram detector 10 according to this embodiment includes an electrocardiogram generator 12, a pair of steering electrodes 16A and 16B, and seat electrodes 18A and 18B.

A pair of steering electrodes 16A and 16B are provided over the entire circumference of the steering wheel 14 for steering the vehicle. A pair of steering electrodes 16A and 16B are provided on the steering wheel 14 corresponding to the left and right hands of the driver. That is, one steering electrode 16A is provided in a region of the steering wheel 14 corresponding to the driver's left hand, and the other steering electrode 16B is provided in a region of the steering wheel 14 corresponding to the driver's right hand.

When the driver grips the steering wheel 14, the driver's hands are brought close to the steering electrodes 16A, 16B, causing capacitive coupling between the driver's hands and the steering electrodes 16A, 16B to form a capacitor. The steering electrodes 16A, 16B are also electrically connected to the electrocardiographic waveform generator 12, and the electrocardiographic waveform generator 12 outputs from the steering electrodes 16A, 16B ion current changes associated with electrical activity during heart beats. (AC current) is detected as a current signal.

The seat electrodes 18A and 18B are provided on the seat cushion of the vehicle seat 20 below the heart position of the driver seated on the vehicle seat 20, and are covered with a seat cover (not shown). When the occupant sits on the vehicle seat 20, the seat electrodes 18A and 18B come close to the buttocks of the occupant through the occupant's clothing and the seat cover. One sheet electrode 18B is connected to the electrocardiographic waveform generator 12, and the other sheet electrode 18A is grounded. Although FIG. 1 shows an example in which the sheet electrodes 18A and 18B are arranged in the width direction of the vehicle (right and left of the driver), the arrangement is not limited to this. For example, the sheet electrodes 18A and 18B may be arranged in the longitudinal direction of the vehicle (front and rear of the driver). Alternatively, the sheet electrodes 18A, 18B may be arranged in other directions. Also, the seat electrodes 18A and 18B may be provided at positions other than the seat cushion of the vehicle seat 20 . For example, it may be provided on the seat back of the vehicle seat 20 .

The electrocardiogram generator 12 generates an electrocardiogram of the driver based on current signals input from the steering electrodes 16A and 16B and the seat electrodes 18B.

Next, the configuration of the electrocardiographic waveform generator 12 will be described. FIG. 2 is a block diagram showing the configuration of the electrocardiographic waveform generator 12. As shown in FIG.

The electrocardiographic waveform generator 12 includes a connection section 24 , voltage followers 26 A and 26 B, a differential amplifier 22 as a detection section, an ADC (Analog to Digital Converter) 28 and a control section 30 .

The steering electrode 16A, the steering electrode 16B, and the seat electrode 18B are connected to the input side of the connecting portion 24, and the voltage followers 26A and 26B are connected to the output side. The voltage followers 26A and 26B are connected to the input terminals of the differential amplifier 22, respectively, and perform impedance conversion to increase the strength of the input signal of the differential amplifier 22. FIG.

The connection unit 24 includes a plurality (four in this embodiment) of switching units 24A, 24B, 24C, and 24D, and is connected to the input terminals of the differential amplifier 22 connected to the voltage followers 26A and 26B. It has a function to selectively switch the electrodes of In the present embodiment, the connection unit 24 selects two electrodes from among the pair of steering electrodes 16A and 16B, the sheet electrode 18B, and the ground GND as the ground electrode, from which an electrocardiogram waveform can be derived, as inputs to the differential amplifier 22. switch to connect.

The switching sections 24A, 24B, 24C each have four contacts, and the switching section 24D has two contacts.

Contact points of the switching section 24A are connected to the steering electrode 16A, the voltage follower 26A, the voltage follower 26B, and the ground GND.

Further, respective contacts of the switching section 24B are connected to the steering electrode 16B, the voltage follower 26A, the voltage follower 26B, and the ground GND.

Further, respective contacts of the switching section 24C are connected to the sheet electrode 18B, the voltage follower 26A, the voltage follower 26B, and the ground GND.

Each electrode of the switching section 24D is connected to the voltage follower 26B and the ground GND.

The connection unit 24 selectively switches electrodes for connection to the input terminals of the differential amplifier 22 . The connection unit 24 selects a combination of electrodes and switches the connections of the switching units 24A to 24D so that the driver's heart is positioned between the electrodes, and the differential amplifier 22 generates an electrocardiographic waveform. can be detected.

In this embodiment, as a combination of electrodes connected to the input terminals of the differential amplifier 22, the combinations shown in FIG. 3 are possible. FIG. 3 is a diagram showing combinations of electrodes connected to the input terminals of the differential amplifier 22 in the vehicle electrocardiographic detector 10 according to this embodiment. 3, the steering electrode 16A is indicated as EL1, the steering electrode 16B as EL2, and the seat electrode 18B as EL3.

Specifically, the connecting portion 24 connects the steering electrode 16A and the steering electrode 16B to the + terminal of the differential amplifier 22, and connects the seat electrode 18B to the - terminal of the differential amplifier 22. FIG. This connection is made when the driver is operating the steering wheel with both hands.

Also, the connecting portion 24 connects the steering electrode 16A to the positive terminal of the differential amplifier 22, and connects the seat electrode 18B to the negative terminal of the differential amplifier 22. FIG. This connection is made when the driver is steering with only his or her left hand.

Further, the connecting portion 24 connects the steering electrode 16B to the positive terminal of the differential amplifier 22, and connects the seat electrode 18B to the negative terminal of the differential amplifier 22. FIG. This connection is made when the driver is operating the steering wheel with only his or her right hand.

Further, the connecting portion 24 connects the steering electrode 16A to the positive terminal of the differential amplifier 22, and connects the steering electrode 16B to the negative terminal of the differential amplifier 22. FIG. This connection is made when there is a distance between the buttocks and the seat electrode 18B because the driver wears thick trousers or the like.

Also, the connecting section 24 connects the steering electrode 16A to the positive terminal of the differential amplifier 22, and connects the negative terminal of the differential amplifier 22 to the ground GND. This connection is made when the driver operates the steering wheel only with the left hand and there is a distance between the buttocks and the seat electrode 18B.

Also, the connecting portion 24 connects the steering electrode 16B to the positive terminal of the differential amplifier 22, and connects the negative terminal of the differential amplifier 22 to the ground GND. This connection is made when the driver operates the steering wheel only with the right hand and there is a distance between the buttocks and the seat electrode 18B.

Also, the connecting portion 24 connects the sheet electrode 18B to the + terminal of the differential amplifier 22 and connects the ground GND to the - terminal of the differential amplifier 22 . This connection is made when the driver does not hold the steering wheel 14 firmly.

On the other hand, the differential amplifier 22 detects the differential voltage of the electrodes connected to the two input terminals and outputs it to the ADC 28 . Specifically, the differential amplifier 22 amplifies the difference between the two input signals from the electrodes connected to the two input terminals by a constant coefficient.

The ADC 28 converts the analog electrical signal obtained from the differential amplifier 22 into a digital signal and outputs the digital signal to the control section 30 .

The control unit 30 is composed of a computer including a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and a non-volatile memory such as a flash memory. By executing a program stored in advance in the memory, the CPU controls the connection unit 24 to selectively switch the electrodes connected to the input terminals of the differential amplifier 22, and generates an electrocardiographic waveform. and output. Specifically, the control unit 30 sequentially switches to the combination of the electrodes in FIG. 3 described above, and controls switching to a connection in which the S/N ratio as signal strength is equal to or greater than a predetermined threshold value, or the S/N ratio is the highest. I do. Specifically, since the waveform corresponding to the electrocardiographic waveform output from the differential amplifier 22 includes an R wave (maximum peak value) and an S wave (minimum peak value) as shown in FIG. performs control to retrieve and switch the combination of electrodes in which the potential difference of the RS wave is greater than or equal to the threshold as the S/N ratio.

Next, specific processing performed by the control unit 30 of the vehicle electrocardiographic detection apparatus 10 according to the present embodiment configured as described above will be described. FIG. 5 is a flow chart showing a first example of the flow of processing performed by the control unit 30 of the vehicle electrocardiographic detection apparatus 10 according to this embodiment. 5 may be started, for example, when an ignition switch (not shown) is turned on, or when an instruction to start detection of an electrocardiogram waveform is given to the control unit 30. FIG.

At step 100 , the control unit 30 switches the connection unit 24 and proceeds to step 102 . The connection part 24 is switched to one of the electrode combinations shown in FIG. 3 .

At step 102 , the control unit 30 acquires the result of differential amplification by the differential amplifier 22 and proceeds to step 104 .

At step 104 , the control unit 30 determines whether or not all the electrode combinations have been switched by the connection unit 24 . This determination is to determine whether or not the differential amplification result has been acquired by switching to the electrode combination shown in FIG. If the determination is negative, the process returns to step 100, the above-described processing is repeated, and the differential amplification result is acquired by changing the switching of the connection unit 24, and if the determination is affirmative, step 106 Move to

At step 106, the control unit 30 switches the connection by the connection unit 24, and ends the series of processes. In the first example, the control unit 30 specifies the electrode combination having the highest S/N ratio among the differential amplification results acquired by switching to all electrode combinations, and the connection unit 24 The control unit 30 controls the switching of . This makes it possible to more accurately detect electrical signals in the living body.

FIG. 6 is a flow chart showing a second example of the flow of processing performed by the control unit 30 of the vehicle electrocardiographic detection apparatus 10 according to this embodiment. 6 may be started, for example, when an ignition switch (not shown) is turned on, or when an instruction to start detection of an electrocardiogram waveform is issued to the control unit 30. FIG. Also, the same processing as the processing in FIG. 5 will be described by attaching the same reference numerals.

At step 100 , the control unit 30 switches the connection unit 24 and proceeds to step 102 . The connection part 24 is switched to one of the electrode combinations shown in FIG. 3 .

At step 102 , the control unit 30 acquires the result of differential amplification by the differential amplifier 22 and proceeds to step 103 .

At step 103, the control unit 30 determines whether or not the result of differential amplification by the differential amplifier 22 acquired at step 102, that is, the S/N ratio of the electrocardiographic waveform is equal to or greater than a predetermined threshold. If the determination is negative, the process returns to step 100, the above-described processing is repeated, the switching of the connection unit 24 is changed, and the differential amplification result is obtained. End the process. That is, the connection portion 24 can be switched to a combination of electrodes having an S/N ratio equal to or higher than the threshold.

FIG. 7 is a flow chart showing a third example of the flow of processing performed by the control unit 30 of the vehicle electrocardiographic detection apparatus 10 according to this embodiment. 7 may be started, for example, when an ignition switch (not shown) is turned on, or when an instruction to start detection of an electrocardiographic waveform is issued to the control unit 30. FIG. Also, the same processing as the processing in FIGS. 5 and 6 will be described with the same reference numerals.

At step 96 , the controller 30 identifies the driver and proceeds to step 98 . For identification of the driver, for example, a plurality of switches corresponding to the driver may be provided and the driver may be identified from the operating state of each switch. Alternatively, a camera for photographing the driver may be provided in the vehicle interior, and the pre-registered driver may be identified from the photographed image of the camera. Alternatively, a biometric authentication unit that performs biometric authentication such as fingerprint or face authentication may be provided to identify a pre-registered driver. Note that step 96 corresponds to the identification section.

At step 98 , control unit 30 reads the switching order of connection unit 24 corresponding to the identified driver, and proceeds to step 101 . For example, the processing of the first example shown in FIG. Read the switching order.

At step 101 , the control unit 30 switches the connection unit 24 according to the read switching order, and proceeds to step 102 .

At step 102 , the control unit 30 acquires the result of differential amplification by the differential amplifier 22 and proceeds to step 103 .

At step 103, the control unit 30 determines whether or not the result of differential amplification by the differential amplifier 22 acquired at step 102, that is, the S/N ratio of the electrocardiographic waveform is equal to or greater than a predetermined threshold. If the determination is negative, the process returns to step 101, the above-described processing is repeated, the switching of the connection section 24 is changed to the next combination of electrodes in the switching order, and the differential amplification result is obtained. If the result is affirmative, the process proceeds to step 108 . That is, the connection portion 24 can be switched to a combination of electrodes having an S/N ratio equal to or higher than the threshold. In addition, since the connection parts 24 are switched in the order of switching for each driver, it is possible to quickly switch to a combination of electrodes with a high S/N ratio in consideration of the habits of the driver.

At step 108, the control unit 30 updates the switching order of the connection unit 24 and ends the series of processes. In other words, since the electrodes are switched in order of the S/N ratio, the combination of electrodes can usually be determined immediately. For example, the switching order of the determined electrode combination is moved up by one, or the switching order is changed to the first, and the switching order is updated. As a result, the switching order is sequentially updated by learning, and the combination of electrodes with a high S/N ratio can be detected early.

(Second embodiment)
Next, a vehicle electrocardiographic detection apparatus according to a second embodiment will be described. FIG. 8 is a diagram showing a schematic configuration of a vehicle electrocardiographic detection apparatus according to this embodiment. It should be noted that the same reference numerals may be given to the same parts as in the above-described embodiment, and the description thereof may be omitted.

In the above-described embodiment, it is necessary to detect the signal strength (S/N ratio) for all combinations of electrodes connected to the input terminals of the differential amplifier 22, and it takes time to determine switching of the connection section 24. Therefore, in the present embodiment, a plurality of differential amplifiers 22A, 22B, 22C (three in FIG. 8) and a plurality of ADCs 28A, 28B, 28C are provided to shorten the time required to determine switching of the connection section 25. FIG.

The electrocardiographic waveform generating apparatus 13 according to this embodiment includes a connecting section 25, voltage followers 26A to 26F, differential amplifiers 22A to 22C, ADCs 28A to 28C, and a control section 31, as shown in FIG.

The steering electrode 16A, the steering electrode 16B, and the seat electrode 18B are connected to the input side of the connection portion 25, and the voltage followers 26A to 26F are connected to the output side. The voltage followers 26A-26F are connected to the input terminals of the differential amplifiers 22A-22C, respectively, and perform impedance conversion to increase the strength of the input signals of the differential amplifiers 22A-22C.

The connection unit 25 includes a plurality (three in this embodiment) of switching units 25A to 25C, and is for connecting to the input terminals of the differential amplifiers 22A to 22C connected to the voltage followers 26A to 26F. It has the function of selectively switching the electrodes. In the present embodiment, the connection unit 25 selectively uses two electrodes from among the pair of steering electrodes 16A and 16B, the sheet electrode 18B, and the ground GND to derive electrocardiogram waveforms as inputs to the differential amplifiers 22A to 22C. to connect.

Each of the switching units 25A-25C has four contacts. The steering electrode 16A is connected to a voltage follower 26A, the steering electrode 16B is connected to a voltage follower 26C, and the seat electrode 18B is connected to a voltage follower 26E.

Contact points of the switching section 25A are connected to the steering electrode 16B, the voltage follower 26B, the seat electrode 18B, and the ground GND.

Further, respective contacts of the switching section 25B are connected to the steering electrode 16A, the voltage follower 26D, the seat electrode 18B, and the ground GND.

Further, respective contacts of the switching section 25C are connected to the steering electrode 16B, the voltage follower 26F, the steering electrode 16A and the ground GND.

The connection unit 25 selectively switches the electrodes to be connected to the input terminals of the three differential amplifiers 22A to 22C. The connection unit 25 selects a combination of electrodes and switches the connection of each of the switching units 25A to 25C. Electrocardiographic waveforms can be detected.

In this embodiment, the three differential amplifiers 22A to 22C share the work, and differential amplification results are obtained from combinations of the electrodes shown in FIG. . A switching unit may be further added to obtain differential amplification results for all combinations of electrodes shown in FIG.

On the other hand, each of the differential amplifiers 22A-22C detects the differential voltage of the electrodes connected to the two input terminals and outputs it to the corresponding ADCs 28A-28C. Specifically, the differential amplifiers 22A to 22C amplify the difference between two input signals from electrodes connected to two input terminals by a constant coefficient.

ADC 28A is connected to the output terminal of differential amplifier 22A, ADC 28B is connected to the output terminal of differential amplifier 22B, and ADC 28C is connected to the output terminal of differential amplifier 22C. Each of the ADCs 28A-28C converts the analog electrical signal obtained from each of the differential amplifiers 22A-22C into a digital signal and outputs the digital signal to the controller 31. FIG.

Also, the control unit 31 is configured by a computer including a CPU, a ROM, a RAM, and a non-volatile memory such as a flash memory, as in the above embodiment. The CPU executes a program pre-stored in the memory to control the connection unit 25 to selectively switch the electrodes connected to the input terminals of the differential amplifiers 22A to 22C. Generate and output shapes. Specifically, the control unit 31 sequentially switches the input terminals of the differential amplifiers 22A to 22C to the combination of the electrodes shown in FIG. Control is performed to switch to a connection that is equal to or higher than a predetermined threshold value or has the highest S/N. Also in the present embodiment, the control unit 31 performs switching control by searching for a combination of electrodes in which the potential difference of the RS wave is greater than or equal to the threshold as the S/N ratio. In the present embodiment, the three differential amplifiers 22A to 22C share the load, and the differential amplification result for each combination of electrodes can be detected. Combinations can be detected. As a method for detecting a combination of electrodes having a high S/N ratio, as in the above embodiment, all electrode combinations may be switched to select an electrode combination having the maximum signal intensity. Alternatively, the combination of electrodes may be sequentially switched to select a combination equal to or greater than the threshold. Also, when switching to a combination of electrodes whose signal strength is equal to or greater than the threshold, the switching order may be learned as in the above embodiment.

In each of the above embodiments, an example in which two sheet electrodes 18A and 18B are provided has been described, but the present invention is not limited to this, and the grounded sheet electrode 18A may be omitted. Although noise can be suppressed by the grounded sheet electrode 18A, it is possible to generate an electrocardiogram waveform even if the sheet electrode 18A is omitted.

Further, although the processing performed by the control units 30 and 31 in the above embodiments has been described as software processing, the processing is not limited to this. For example, it may be a process performed by hardware, or may be a process combining both hardware and software.

Further, the processing performed by the control units 30 and 31 in the above embodiments may be stored in a storage medium as a program and distributed.

Furthermore, the present invention is not limited to the above, and it goes without saying that other than the above, various modifications can be made without departing from the scope of the invention.

DESCRIPTION OF SYMBOLS 10... Electrocardiogram detection apparatus for vehicles 12... Electrocardiogram waveform generator 13... Electrocardiogram waveform generator 14... Steering wheel 16A... Steering electrode 16B... Steering electrode , 18B... seat electrode, 20... vehicle seat, 22... differential amplifier, 22A to 22C... differential amplifier, 24... connection part, 25... connection part, 30. . . control unit 31 .. control unit GND .. ground

Claims (6)

a pair of steering electrodes provided on the steering wheel corresponding to the left and right hands of the driver;
a seat electrode provided on a vehicle seat below the position of the heart of a seated driver;
a grounded ground electrode;
a detection unit that detects a differential voltage between two inputs;
a connection unit that selectively switches and connects two electrodes from among the pair of steering electrodes, the seat electrode, and the ground electrode that can derive an electrocardiogram waveform as inputs of the detection unit;
including
The connection unit includes a plurality of switching units corresponding to each of the pair of steering electrodes and the seat electrode, and each of the switching units can be switched to the + terminal, - terminal, and ground terminal of the detection unit. A car electrocardiographic detector. A predetermined combination of two of the pair of steering electrodes, the seat electrode, and the ground electrode is sequentially switched to select a combination in which the intensity of the differential voltage detected by the detection unit is equal to or greater than a predetermined threshold. 2. The vehicle electrocardiogram detection apparatus of claim 1, further comprising a controller for controlling the connection to select. a pair of steering electrodes provided on the steering wheel corresponding to the left and right hands of the driver;
a seat electrode provided on a vehicle seat below the position of the heart of a seated driver;
a grounded ground electrode;
a detection unit that detects a differential voltage between two inputs;
a connection unit that selectively switches and connects two electrodes from among the pair of steering electrodes, the seat electrode, and the ground electrode that can derive an electrocardiogram waveform as inputs of the detection unit;
controlling the connection unit so as to sequentially switch a predetermined combination of two of the pair of steering electrodes, the seat electrode, and the ground electrode; A control unit that selects the combination when the threshold value is exceeded;
A vehicle electrocardiographic detection device comprising: further comprising an identification unit that identifies the driver;
The control unit learns a switching order for sequentially switching between the two combinations from the control result of the control unit for each driver identified by the identification unit, and the switching order learned according to the identification result of the identification unit. 4. The vehicular electrocardiographic detection apparatus according to claim 2, further controlling said connecting portion so as to sequentially switch between . Two predetermined combinations of the pair of steering electrodes, the seat electrode, and the ground electrode are sequentially switched to select the combination that maximizes the strength of the differential voltage detected by the detection unit. 2. The vehicular electrocardiographic detection apparatus according to claim 1, further comprising a control unit for controlling said connection unit . including a plurality of the detection units,
5. The connection unit selectively switches and connects two of the pair of steering electrodes, the seat electrode, and the ground electrode as inputs to each of the plurality of detection units. 2. The vehicle electrocardiographic detection device according to claim 1.

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