JP5637108B2 - ECG measurement device for vehicles - Google Patents

Description

  The present invention relates to a vehicle electrocardiograph that measures an electrocardiogram waveform of a vehicle driver.

  2. Description of the Related Art Conventionally, an electrocardiogram that is detected in the form of a graph by detecting an electrical activity of the heart using an electrode for measuring body potential has been widely used in the medical field. Research has been conducted on a technique for measuring such an electrocardiogram waveform for a driver who is driving a vehicle. By monitoring the activity of the driver's heart, various techniques resulting from abnormalities in the driver's heart during driving can be performed. The inconvenience is expected to be suppressed in advance.

  As such a device, as disclosed in Patent Document 1, a direct electrode for detecting the body potential of the driver by contacting the driver's skin is provided on the steering, and the seat is not contacted with the driver's skin. An electrocardiogram for a vehicle that provides a capacitively coupled electrode that detects the body potential of the driver, connects both electrodes and a measurement circuit, and measures the electrocardiogram waveform of the driver based on the potential at the direct electrode and the potential at the capacitively coupled electrode. A measurement device is disclosed.

JP 2011-24903 A

  However, in such conventional devices, the distance between both electrodes and the measurement circuit is long, and the signal detected by both electrodes is very small. Therefore, in a noisy environment such as a vehicle, it is greatly affected by the noise. There is a problem that it is sometimes difficult to obtain an ECG waveform appropriately.

  The subject of this invention is providing the electrocardiograph for vehicles which is hard to receive to the influence of noise, even if the distance from an electrode is long.

In order to achieve this problem, the present invention has taken the following measures in order to solve the problem. That is,
A direct electrode provided on the steering wheel of the vehicle for detecting the driver's body potential in contact with the driver's skin;
A capacitively coupled electrode provided on the vehicle seat for detecting the body potential of the driver in an electrically insulated state;
In the vehicle electrocardiogram measuring device, comprising: an electrocardiogram waveform measuring instrument that measures the driver's electrocardiogram waveform based on the potential at the direct electrode and the potential at the capacitively coupled electrode;
A steering-side amplifier that amplifies the detection signal from the direct electrode and outputs it to the electrocardiogram waveform measuring instrument is disposed in a housing that rotates with the rotation of the steering wheel, and a flexible flat cable is wound around the steering shaft. By connecting the electrocardiogram waveform measuring instrument and the steering side amplifier with a spiral cable constituted by the above, the steering side amplifier is provided on the steering wheel side with respect to the spiral cable,
An electrocardiograph for a vehicle comprising: a seat-side amplifier that amplifies a detection signal from the capacitively coupled electrode and outputs the amplified signal to the electrocardiogram waveform measuring device; That is it.

The seat-side amplifier may be housed in urethane in the seat portion below the skin of the seat portion of the seat. The direct electrode or the capacitively coupled electrode may be divided into a plurality of parts. Furthermore, the capacitively coupled electrode may be fixed to the back side of the skin of the sheet. Moreover, it is good also as a structure which used as the said direct electrode or the said capacitive coupling type | mold electrode the skin which used the electrically conductive sewing thread, or the skin which consists of an electroconductive woven fabric. Of the skin of the sheet for fixing the capacitively coupled electrode, by recessing a part of the back side of the skin to which the capacitively coupled electrode is fixed, the recessed part is thinner than the surrounding part. It is good also as the formed structure.

  In the vehicle electrocardiograph of the present invention, the detection signal by the direct electrode is amplified by the steering side amplifier before passing through the spiral cable, and the detection signal by the capacitive coupling type electrode is also amplified by the seat side amplifier. The noise level is relatively small when the signal is input to the cable, and even if the distance from the electrode is long, it is not easily affected by noise, and is amplified by the steering-side amplifier before passing through the spiral cable. Even if noise is picked up, there is an effect that the noise level becomes relatively small.

  Further, noise resistance can be further improved by providing the seat side amplifier inside the seat. Furthermore, noise resistance can be improved by dividing the electrode into a plurality of portions and extracting a portion where the amplitude level of the detection signal increases. By fixing the capacitive coupling electrode to the sheet, generation of noise due to rubbing can be suppressed. Moreover, by using a conductive sewing thread as an electrode, the design can be improved and noise can be reduced.

It is a schematic block diagram of the electrocardiograph for vehicles as one embodiment of the present invention. It is an expansion side view of the steering wheel of this embodiment. It is an enlarged side view of the sheet of this embodiment. It is a principal part expanded sectional view of the seat seat part of this embodiment. It is a front view of the steering wheel of another embodiment. It is a perspective view of the seat seat part of another embodiment.

DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the drawings.
FIG. 1 is a schematic block diagram of a vehicle electrocardiograph as an embodiment of the present invention. As shown in FIG. 1, reference numeral 1 denotes a steering wheel, and a direct electrode 2 formed of a conductive material is provided on the steering wheel 1 so as to be exposed on the outer peripheral surface of the steering wheel 1. The direct electrode 2 is an electrode for detecting the body potential of the driver by contacting the skin of the driver of the vehicle. For example, the electrode 2 is formed of chrome plating resin and attached to the surface of the steering wheel 1. Good.

  The seat 4 on which the driver is seated is provided with a capacitively coupled electrode 6 on the seat 4a. The capacitively coupled electrode 6 is an electrode that forms a virtual capacitor with the driver's body without contacting the driver's skin, and detects the driver's body potential by capacitive coupling in an electrically insulated state. .

  The direct electrode 2 and the electrocardiogram waveform measuring instrument 8 are connected by a steering-side signal line 10, and the capacitive coupling electrode 6 and the electrocardiogram waveform measuring instrument 8 are connected by a seat-side signal line 12, so that the driver's body The potential of the capacitively coupled electrode 6 that varies in accordance with the variation in potential is transmitted to the electrocardiogram waveform measuring instrument 8.

  The electrocardiogram waveform measuring instrument 8 includes a voltage follower, an amplifier, a microcomputer, a memory, and the like (not shown), and calculates a potential difference between the body potentials of the driver detected via the direct electrode 2 and the capacitively coupled electrode 6. . A voltage signal based on this potential difference is subjected to filtering processing and the like, sampled at a predetermined cycle, and stored in a memory as time series data. This time series data is an electrocardiogram waveform.

  The electrocardiogram waveform measuring instrument 8 monitors whether or not there is an abnormality in the electrocardiogram waveform, and can perform driving support control such as issuing an alarm when the abnormality is determined, or gradually stopping the vehicle. it can. It is also possible to monitor whether or not there is an abnormality in the waveform in the facility outside the vehicle by transmitting data related to the electrocardiogram waveform to the facility outside the vehicle by wireless communication.

  The electrocardiogram waveform measuring instrument 8 is connected to the vehicle control computer 14 and is configured to receive an output from a vehicle speed sensor or the like. When it is determined that the vehicle is running, the R wave peak of the electrocardiogram waveform is determined. If the driver's heart condition is determined globally based on the interval of the (wave height of R wave) and the vehicle is determined to be stopped, the entire ECG waveform including the R wave peak in the ECG waveform The driver's heart condition may be determined more strictly based on the above.

  Here, the electrocardiogram waveform mainly includes the P wave reflecting the electrical excitation of the atrium, the Q, R and S waves reflecting the electrical excitation of the ventricle, and the process of repolarizing the excited myocardial cells of the ventricle. The wave height (potential difference) of the R wave is the largest.

  Accordingly, while the vehicle is running, the heart state of the driver is determined globally based on the interval of the R wave peak, which is the portion of the ECG waveform having the largest wave height. On the other hand, since the driver is likely to be in a resting state while the vehicle is stopped, noise such as myoelectric potential can be reduced. Therefore, the driver is based on the entire electrocardiogram waveform including the T wave and the P wave whose wave height is smaller than the R wave. More accurately determine the heart condition of

  While the vehicle is running, only the R wave peak is detected from the electrocardiogram waveform, and the heart rate per minute is calculated from the cycle. Then, the fluctuation of the heart rate is monitored from the RR interval, and the fluctuation of the heart rate is subjected to frequency analysis to calculate a low frequency component and a high frequency component. Then, the presence or absence of arrhythmia is determined based on the calculated heart rate and the low frequency component / high frequency component ratio. When it is determined that there is a risk of arrhythmia, control may be performed such that the vehicle is gradually stopped by interference control with the vehicle drive device or brake device, or a warning screen is displayed on the display device.

  When it is determined that there is a risk of arrhythmia, it is automatically notified to a pre-registered contact via a communication device, or a horn is sounded to notify the emergency situation outside the vehicle, or a light is blinked. It is good to do.

  A steering-side amplifier 16 is interposed in the steering-side signal line 10 that connects the direct electrode 2 and the electrocardiogram waveform measuring instrument 8, and the steering-side amplifier 16 amplifies the detection signal from the direct electrode 2 to generate an electrocardiogram waveform. This is a known amplifier that outputs to the measuring instrument 8.

  As shown in FIG. 2, a spiral cable 10a is partially used for the steering side signal line 10 between the electrocardiogram waveform measuring instrument 8 and the steering side amplifier 16. In this embodiment, the spiral cable 10a is connected to the spiral cable 10a. Is a thin flat flexible cable that is wound around the steering shaft 18.

  The spiral cable 10 a is configured to be able to transmit and receive signals without being affected by the rotation of the steering shaft 18 by being loosened and tightened in accordance with the rotation of the steering shaft 18. In addition to the steering signal line 10, the spiral cable 10a is provided with a plurality of other power lines and signal lines. The steering-side amplifier 16 is provided directly in the vicinity of the electrode 2 and is disposed in a housing 20 that rotates with the rotation of the steering wheel 1.

  A sheet-side amplifier 22 is interposed in the sheet-side signal line 12 that connects the capacitively coupled electrode 6 and the electrocardiogram waveform measuring instrument 8, and the sheet-side amplifier 22 amplifies the detection signal from the capacitively coupled electrode 6. This is a known amplifier that outputs to the electrocardiogram waveform measuring instrument 8. The steering side amplifier 16 and the seat side amplifier 22 are both grounded by a ground line 24. The steering side amplifier 16 and the seat side amplifier 22 have the same performance.

  As shown in FIG. 3, the seat-side amplifier 22 is provided inside the seat 4 a of the seat 4, and the length of the seat-side signal line 12 between the capacitive coupling electrode 6 and the seat-side amplifier 22 is short. It is provided in the vicinity of the capacitively coupled electrode 6 so as to be. As shown in FIG. 4, the hard urethane 26, the urethane 28, and the skin 30 are sequentially laminated on the seat 4, and a recess 26 a is formed in the hard urethane 26 of the seat portion 4 a on which the driver's buttocks ride. Corresponding to the recess 26a, a hole 28a is formed in the urethane 28, the seat side amplifier 22 is accommodated in the recess 26a, the seat side amplifier 22 is provided below the skin 30 of the seat 4a, It is housed inside the urethane 28 of the seat 4a.

  In the present embodiment, the capacitively coupled electrode 6 is a sheet-like conductor made of conductive fibers, and a rubber plate 32 is disposed on the back side of the capacitively coupled electrode 6. A guard electrode 34 is provided on the lower surface of the rubber plate 32 so as to cover the back side of the capacitive coupling electrode 6 and shield noise intrusion. The capacitive coupling electrode 6, the rubber plate 32, the guard electrode are provided. 34 is integrally fixed by an adhesive or the like.

  Further, the capacitively coupled electrode 6, the rubber plate 32, and the guard electrode 34 are accommodated in the recess 26 a and the hole 28 a on the upper side of the sheet side amplifier 22. The skin 30 corresponding to the recess 26a is thinly formed. In this embodiment, the back side of the skin 30 is recessed, and the capacitive coupling electrode 6 is fixed to the back side of the thinned skin 30 with an adhesive or the like. Yes. Since the capacitively coupled electrode 6 is fixed to the skin 30 of the seat 4, vibration (friction) noise between the skin 30 of the seat 4 and the capacitively coupled electrode 6 generated by the vibration of the vehicle can be improved. Can do. The skin 30 is made of a known non-conductive material such as leather or fabric.

  Next, the operation of the above-described vehicle electrocardiograph of the present embodiment will be described. When the driver is seated on the seat 4 and the driving is started, a detection signal from the direct electrode 2 in direct contact with the driver's hand is input to the steering side amplifier 16 and amplified by the steering side amplifier 16 to be spiral. The signal is input to the electrocardiogram waveform measuring instrument 8 through the cable 10 a and the steering-side signal line 10.

  Since the detection signal is amplified by the steering-side amplifier 16 before passing through the spiral cable 10a, even if noise is picked up by the spiral cable 10a, the noise level is relative when it is input to the electrocardiogram waveform measuring instrument 8. And the S / N ratio is improved.

  Further, a detection signal from the capacitive coupling electrode 6 is input to the sheet side amplifier 22, amplified by the sheet side amplifier 22, and input to the electrocardiogram waveform measuring instrument 8 through the sheet side signal line 12. The electrocardiogram waveform measuring instrument 8 performs a filtering process or the like on the voltage signal based on the potential difference between the two signals and samples it at a predetermined cycle to obtain an electrocardiogram waveform.

  Since the detection signal from the capacitive coupling electrode 6 is also amplified by the sheet side amplifier 22, even if noise is picked up by the sheet side signal line 12, when the signal is input to the electrocardiogram waveform measuring device 8, the noise level is relative. When the potential difference between the two signals is calculated, the same vehicle noise can be canceled, so that noise resistance can be improved.

  Further, since the capacitive coupling electrode 6 is fixed to the skin 30, noise generated by rubbing between the capacitive coupling electrode 6 and the skin 30 can be suppressed, so that noise can be reduced.

  The direct electrode 2 may be divided into a plurality along the circumferential direction of the steering wheel 1, or the capacitive coupling electrode 6 may be divided into front, rear, left and right. As the electrode area increases, it becomes easier to pick up noise in the space as an antenna, and the resistance to noise can be improved by dividing the electrodes 2 and 6 and comparing the divided electrodes to extract the portion where the amplitude level of the detection signal increases. .

  As shown in FIG. 5, instead of the direct electrode 2 described above, a conductive sewing thread 42 may be used at the seam of the cover of the steering wheel 1. Thereby, it becomes the thing excellent in the designability. In addition, as shown in FIG. 6, the capacitive coupling electrode 6 may be fixed to the skin 30 with a conductive sewing thread 44, or the sewing thread 44 may be capacitively coupled without using the capacitive coupling electrode 6 described above. It may be used as a mold electrode. Even if the sewing thread 44 is exposed on the surface, electrical insulation from the sewing thread 44 is maintained by the driver's clothing, and noise can be reduced. Furthermore, the skin of the steering wheel 1 and the skin of the seat 4 may be formed from a conductive woven fabric, and these skins may be used as direct electrodes or capacitively coupled electrodes.

  The present invention is not limited to such embodiments as described above, and can be implemented in various modes without departing from the gist of the present invention.

DESCRIPTION OF SYMBOLS 1 ... Steering wheel 2 ... Direct electrode 4 ... Seat 4a ... Seat part 6 ... Capacitive coupling type electrode 8 ... Electrocardiogram waveform measuring instrument 10 ... Steering side signal wire 10a ... Spiral cable 12 ... Seat side signal wire 14 ... Vehicle control computer 16 ... Steering side amplifier 22 ... Seat side amplifier 24 ... Ground wire 26 ... Hard urethane 26a ... Recess 28 ... Urethane 28a ... Hole 30 ... Skin 32 ... Rubber plate 34 ... Guard electrodes 42, 44 ... Sewing thread

Claims (6)

A direct electrode provided on the steering wheel of the vehicle for detecting the driver's body potential in contact with the driver's skin;
A capacitively coupled electrode provided on the vehicle seat for detecting the body potential of the driver in an electrically insulated state;
In the vehicle electrocardiogram measuring device, comprising: an electrocardiogram waveform measuring instrument that measures the driver's electrocardiogram waveform based on the potential at the direct electrode and the potential at the capacitively coupled electrode;
A steering-side amplifier that amplifies the detection signal from the direct electrode and outputs it to the electrocardiogram waveform measuring instrument is disposed in a housing that rotates with the rotation of the steering wheel, and a flexible flat cable is wound around the steering shaft. By connecting the electrocardiogram waveform measuring instrument and the steering side amplifier with a spiral cable constituted by the above, the steering side amplifier is provided on the steering wheel side with respect to the spiral cable,
An electrocardiograph for a vehicle comprising: a seat-side amplifier that amplifies a detection signal from the capacitively coupled electrode and outputs the amplified signal to the electrocardiogram waveform measuring device; . The electrocardiograph for a vehicle according to claim 1, wherein the seat side amplifier is housed in urethane of the seat portion below the skin of the seat portion of the seat. The electrocardiograph for a vehicle according to claim 1, wherein the direct electrode or the capacitively coupled electrode is divided into a plurality of parts. The vehicle electrocardiograph according to any one of claims 1 to 3, wherein the capacitively coupled electrode is fixed to the back side of the skin of the sheet. The vehicle electrocardiogram according to any one of claims 1 to 3, wherein a skin made of a conductive sewing thread or a skin made of a conductive woven fabric is used as the direct electrode or the capacitively coupled electrode. Measuring device. Of the skin of the sheet for fixing the capacitively coupled electrode, by recessing a part of the back side of the skin to which the capacitively coupled electrode is fixed, the recessed part is thinner than the surrounding part. The vehicular electrocardiograph according to claim 4, which is formed.

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