Heart Rate Calculator

Abstract

To provide a heartbeat value calculation device for detecting a body surface motion of an occupant with a simple configuration, and using the body surface motion for heartbeat value calculation.SOLUTION: A heartbeat value calculation device includes a Doppler sensor, a heartbeat value calculation part, a seat belt, and a seat belt detection sensor. The Doppler sensor detects a body surface motion (body motion) of an occupant. The heartbeat value calculation part executes heartbeat value calculation processing for calculating a heartbeat value of the occupant on the basis of a detection value related to the body surface motion detected by the Doppler sensor. The seat belt constrains the occupant. The seat belt detection sensor detects an actuation amount of the seat belt. The heartbeat value calculation part excludes a detection value related to a body surface motion corresponding to the time that the actuation amount exceeds a predetermined amount as an abnormal value from an object for the heartbeat value calculation processing on a condition that the actuation amount of the seat belt exceeds the predetermined amount.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present invention relates to a heart rate value calculation device, and more particularly to a heart rate value calculation device that calculates the heart rate value of a vehicle occupant. [Background technology]

[0002] 2. Description of the Related Art Heart rate value calculation devices that calculate the heart rate value of a vehicle occupant have been proposed in the past (see, for example, Patent Documents 1 and 2).

[0003] The above-mentioned Patent Document 1 discloses a heart rate detection device that accurately detects the heart rate (heart rate value) of a vehicle occupant using a sensor or the like by removing frequency bands caused by vehicle vibrations and the like using a band pass filter. The above-mentioned Patent Document 1 describes that the band pass filter removes signal waveform noise such as low frequency components of 0.5 Hz or less, such as breathing and body surface movements (body movements), and high frequency components of 15 Hz or more, such as engine vibrations, so that only the frequency band of 0.5 Hz to 15 Hz is extracted, and as a result, the heart rate (heart rate value) of the vehicle occupant is accurately detected.

[0004] The above-mentioned Patent Document 2 describes an occupant condition detection device that improves the detection accuracy of the occupant condition by suppressing the influence caused by the body surface motion (body movement) when the occupant operates various devices such as switches and accelerators provided in the vehicle. The above-mentioned Patent Document 2 describes that the occupant's heart rate fluctuation value is calculated based on the detection result of a heart rate sensor that detects the occupant's heart rate (heart rate value), and when the occupant's operation of various devices is detected, the heart rate fluctuation value is calculated excluding the heart rate fluctuation value corresponding to the time when the occupant operated the various devices, thereby excluding the increase in heart rate due to body movement. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2006-55406 A [Patent Document 2] JP 2017-86201 A Summary of the Invention [Problem to be solved by the invention]

[0006] As described in Patent Documents 1 and 2 above, a technique is disclosed for removing signal waveform noise caused by body movements resulting from the occupant's operation of equipment in order to more accurately obtain the heart rate (heart rate value) of a vehicle occupant using a sensor or the like.

[0007] However, since body movements occur even when the occupant does not operate the device, a further body movement detection means is required to detect such body movements. Therefore, there is a demand for a heart rate value calculation device that can detect the body movements of the occupant with a simple configuration and use the detected body movements in the heart rate value calculation.

[0008] The present invention has been made to solve the above problems, and has an object to provide a heart rate value calculation device that can detect the body surface movement of an occupant with a simple configuration and use the detected movement to calculate the heart rate value. [Means for solving the problem]

[0009] In order to achieve the above object, the present invention is configured as follows.

[0010] (1) A heart rate value calculation device according to the present invention comprises a body surface movement detection unit that detects body surface movements of an occupant, a heart rate value calculation unit that performs a heart rate value calculation process that calculates the heart rate value of the occupant based on a detection value related to the body surface movement detected by the body surface movement detection unit, a restraint unit that restrains the occupant, and an actuation amount detection unit that detects an actuation amount of the restraint unit, wherein, on the condition that the actuation amount of the restraint unit exceeds a predetermined amount, the heart rate value calculation unit excludes the detection value related to the body surface movement corresponding to a time when the actuation amount of the restraint unit exceeds the predetermined amount as an abnormal value from the heart rate value calculation process.

[0011] According to the above configuration, abnormal values ​​in the body surface motion (body movement) of the occupant are excluded from the heart rate value calculation process, thereby suppressing the abnormal values ​​from affecting the heart rate value calculation process. Therefore, the heart rate value of the occupant can be accurately calculated. Furthermore, according to the above configuration, it is possible to determine whether to continue or stop measuring the heart rate value depending on the magnitude of the body surface motion of the occupant based on the amount of operation of the restraint section, which can also contribute to ensuring the reliability of the heart rate value calculation. As a result, the body surface motion of the occupant can be detected with a simple configuration without providing a separate device for performing the heart rate value calculation process, so that the heart rate value calculation device can be effectively used for heart rate value calculation.

[0012] (2) In the heart rate value calculation device according to the present invention, preferably, the restraint unit is a seat belt that can be wound and withdrawn, the operation amount detection unit detects the amount of retraction and withdrawal of the seat belt, and the heart rate value calculation unit, on condition that the amount of retraction and withdrawal of the seat belt exceeds a predetermined amount, may determine a detection value related to the body surface motion corresponding to a time when the amount of retraction and withdrawal of the seat belt exceeds the predetermined amount as an abnormal value and exclude it from the target of the heart rate value calculation process. With this configuration, the seat belt is in close contact with the body of the occupant, so that the amount of retraction and withdrawal of the seat belt caused by the body surface motion of the occupant can be directly detected. As a result, abnormal values ​​in the body surface motion of the occupant are excluded from the target of the heart rate value calculation process, thereby suppressing the abnormal values ​​from affecting the heart rate value calculation process. As a result, the heart rate value can be accurately calculated.

[0013] (3) In this case, it is preferable to further include a seat belt detection sensor for detecting the retracted amount and the unretracted amount of the seat belt. With this configuration, the retracted amount and the unretracted amount of the seat belt caused by the body surface movement of the occupant can be easily detected by the seat belt detection sensor.

[0014] (4) In the heart rate value calculation device according to the present invention, the body surface motion detection unit is preferably configured with at least one of a radio wave Doppler sensor, an ultrasonic Doppler sensor, a piezoelectric sensor, and an air pressure sensor. With this configuration, the body surface motion of the occupant can be easily detected by at least one of the radio wave Doppler sensor, the ultrasonic Doppler sensor, the piezoelectric sensor, and the air pressure sensor.

[0015] (5) In the heart rate value calculation device according to the present invention, the body surface motion detection unit is preferably provided in at least one of a seat, a headrest, a steering wheel, and an instrument panel. By providing the body surface motion detection unit in at least one of the seat, the headrest, and the steering wheel, the body surface motion detection unit can be brought into contact with the body of the occupant to detect the body surface motion, and therefore the body surface motion of the occupant can be directly detected. Furthermore, by providing the body surface motion detection unit in the instrument panel, the body surface motion of the occupant can be detected in a non-contact manner, and therefore the body surface motion of the occupant can be effectively detected even if the body surface motion detection unit and the occupant are separated from each other. Effect of the Invention

[0016] According to an aspect of the present invention, it is possible to provide a heart rate value calculation device that can detect the body surface movement of an occupant with a simple configuration and use the detected movement to calculate a heart rate value. [Brief description of the drawings]

[0017] [Figure 1] 1 is a block diagram showing a schematic configuration of a heart rate value calculation device according to an embodiment of the present invention. [Diagram 2] 3A and 3B are diagrams illustrating an example of installation of a seat belt detection sensor according to the present embodiment. [Diagram 3] FIG. 4 is a flow chart relating to calculation of a heart rate value according to the present embodiment. [Figure 4]13A is a graph showing an example of the retracted / unretracted amount of a seat belt versus time, and FIG. 13B is a graph showing an example of heart rate values ​​versus time. [Diagram 5] 10 is a flowchart showing a heart rate value calculation process according to the embodiment. [Figure 6] 13 is a flowchart showing a heart rate value calculation process according to a modified example of the present embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] Hereinafter, a heart rate value calculation device according to an embodiment of the present invention will be described with reference to the accompanying drawings. These drawings are schematic diagrams and are not necessarily drawn to exact scale. In addition, in the drawings, similar components are indicated by the same reference numerals.

[0019] (Overall composition) The overall configuration of a heart rate value calculation device 100 according to this embodiment will be described with reference to Fig. 1 to Fig. 4. The heart rate value calculation device 100 is applied to (mounted on) vehicles in general, such as hybrid cars, electric cars, and self-driving cars. As shown in Fig. 1, the heart rate value calculation device 100 includes a seat unit 10, a seat belt unit 20, a headrest unit 30, and a control unit 40.

[0020] (Seat section) The seat unit 10 includes a seat body 11, a Doppler sensor 12, and a seat pressure sensor 13. The Doppler sensor 12 and the seat pressure sensor 13 are examples of the "body surface motion detection unit" of the present invention.

[0021] The seat body 11 is configured so that occupants such as a driver and a passenger of the vehicle can sit on it, and supports the backs and buttocks of the occupants.

[0022] The Doppler sensor 12 is provided at an arbitrary position such as on the back or seat surface of the seat body 11. In addition to the seat body 11, the Doppler sensor 12 may be provided on at least one of a seat belt 21, a headrest body 31, a steering wheel (not shown), and an instrument panel (not shown), which will be described later.

[0023] The Doppler sensor 12 is configured by at least one of a radio wave Doppler sensor, an ultrasonic Doppler sensor, a piezoelectric sensor, and an air pressure sensor. The Doppler sensor 12 is connected to the control unit 40 so as to be able to communicate information with the control unit 40 by wireless communication or wired communication.

[0024] When an occupant is seated in the seat body 11, the Doppler sensor 12 detects the body surface motion (body movement) of the occupant such as the back and buttocks, and transmits it as an output signal to the control unit 40. The output signal of the Doppler sensor 12 generally includes not only the body surface motion but also heartbeat, breathing, etc. Furthermore, the output signal of the Doppler sensor 12 also includes vibrations due to vibration sources around the occupant to be detected.

[0025] The seat pressure sensor 13 is provided at an arbitrary position such as the back or seat surface of the seat main body 11. When an occupant is seated in the seat main body 11, the seat pressure sensor 13 detects a change in pressure corresponding to the body surface movement of the occupant such as the back or buttocks, and transmits the detected pressure as an output signal to the control unit 40. The seat pressure sensor 13 is connected to the control unit 40 via wireless communication or wired communication so as to be able to communicate information with the control unit 40.

[0026] (Seat belt section) The seat belt section 20 includes a seat belt 21, a seat belt detection sensor 22, a seat buckle confirmation sensor 23, and a shoulder anchor 24. The seat belt 21 is an example of the "restraint section" of the present invention, and the seat belt detection sensor 22 is an example of the "operation amount detection section" of the present invention.

[0027] The seat belt 21 is for fixing (restraining) the occupant to the seat main body 11. As shown in Fig. 2, the seat belt 21 is formed in a belt shape and is provided via a shoulder anchor 24 installed inside the vehicle (inside the vehicle). The seat belt 21 is configured to be retractable and retractable by the occupant's operation.

[0028] The seat belt detection sensor 22 is provided near the shoulder anchor 24. The seat belt detection sensor 22 is connected to the control unit 40 so as to be capable of communicating information with the control unit 40 via wireless communication or wired communication. The seat belt detection sensor 22 detects the retracted amount and the withdrawn amount as the operation amount of the seat belt 21 retracted or withdrawn by the operation of the occupant, and transmits the detected amount as an output signal to the control unit 40. The retracted amount and the withdrawn amount of the seat belt 21 are, for example, the length of the seat belt 21, and the length of the seat belt 21 may be measured directly from the amount of movement of the seat belt 21, or may be calculated from the speed, time, etc. of the seat belt 21 during its movement.

[0029] The seat buckle confirmation sensor 23 is provided on the side of the seat surface of the seat body 11. The seat buckle confirmation sensor 23 is a sensor that confirms that the seat belt 21 is fastened to a seat buckle (not shown). The seat buckle confirmation sensor 23 is connected to the control unit 40 so as to be able to communicate information with the control unit 40 by wireless communication or wired communication. The seat buckle confirmation sensor 23 detects that the seat belt 21 is fastened and transmits the result as an output signal to the control unit 40.

[0030] (Headrest section) The headrest portion 30 is provided on the upper part of the seat body 11 of the seat portion 10. The headrest portion 30 includes a headrest body 31 and a headrest pressure sensor 32. The headrest pressure sensor 32 is an example of the "body surface motion detection portion" of the present invention.

[0031] The headrest body 31 supports the head of the occupant.

[0032] The headrest pressure sensor 32 is provided on the surface (the surface that contacts the head of the occupant) of the headrest main body 31. The headrest pressure sensor 32 is connected to the control unit 40 so as to be capable of communicating information via wireless or wired communication. When the occupant is seated in the seat main body 11, the headrest pressure sensor 32 detects a change in pressure in the head of the occupant in response to the body surface movement, and transmits the detected change to the control unit 40 as an output signal.

[0033] (Control unit) The control unit 40 is a control device that controls the entire vehicle, etc. The control unit 40 includes a heart rate value calculation unit 41.

[0034] In this embodiment, the heart rate value calculation unit 41 performs a heart rate value calculation process to calculate the heart rate value of the occupant based on detection values ​​related to the body surface movement of the occupant detected by at least one of the Doppler sensor 12, the seat pressure sensor 13, and the headrest pressure sensor 32.

[0035] Here, a description will be given of the heart rate value calculation process in the heart rate value calculation unit 41. Here, a description will be given of the heart rate value calculation process for calculating the heart rate value of the occupant based on the detection value related to the body surface movement of the occupant detected by the Doppler sensor 12.

[0036] 3, in step S1, the body surface movement of the occupant is detected by the Doppler sensor 12. Thereafter, a detection value (sensor output) related to the body surface movement of the occupant detected by the Doppler sensor 12 is output to the heart rate value calculation unit 41.

[0037] Next, in step S2, the heart rate value calculation unit 41 performs frequency analysis on the detected values ​​relating to the body surface motion of the occupant.

[0038] Next, in step S3, the heart rate value calculation section 41 selects a heart rate peak from the frequency analysis result and calculates the heart rate interval.

[0039] Finally, in step S4, the heart rate value calculation unit 41 calculates the heart rate value (estimated heart rate) of the occupant from the calculated heart rate interval.

[0040] Furthermore, in this embodiment, on the condition that the amount of operation of the seat belt 21 detected by the seat belt detection sensor 22 (see Figures 1 and 2) exceeds a predetermined amount, the heart rate value calculation unit 41 excludes the detection value related to the body surface movement corresponding to the time when the amount of operation of the seat belt 21 exceeds the predetermined amount as an abnormal value from the heart rate value calculation process.

[0041] Specifically, as shown in Fig. 4(a), the retracted and unretracted amounts of the seat belt 21 detected by the seat belt detection sensor 22 as the amount of operation exceed the cutoff threshold as a predetermined amount in the section from time A to time B. Therefore, in the section from time A to time B, the body surface movement (amount of movement) of the occupant is determined to be large relative to the reference. In other words, in the section from time A to time B, the seat belt 21 moves significantly due to the occupant adjusting his / her posture or other movement, and therefore it is determined that the body surface movement (amount of movement) has increased. As a result, as shown in Fig. 4(b), the detection value related to the body surface movement corresponding to the section from time A to time B is excluded from the heart rate value calculation process as an abnormal value.

[0042] (Heart rate calculation process) The heart rate value calculation process in the heart rate value calculation device 100 according to this embodiment will be described with reference to FIG. 1 and FIG. 3 to FIG.

[0043] 5, in step S10, the seat belt 21 is unwound by the occupant and inserted into the seat buckle, and the seat buckle confirmation sensor 23 confirms that the seat belt 21 is inserted. At this time, the seat belt detection sensor 22 measures the amount (length) of the unwound seat belt 21, and a state in which the amount of the unwound seat belt 21 does not change is set as an initial attitude value, and the measurement result is output to the control unit 40. After that, the process proceeds to step S11.

[0044] In step S11, while the occupant (driver) is driving, the seat belt detection sensor 22 measures the retracted and unretracted amounts of the seat belt 21, and the measurement results are output to the control unit 40. After that, the process proceeds to step S12.

[0045] In step S12, the magnitude (amount of movement) of the occupant's body surface movement is calculated based on the amount of retraction and amount of withdrawal of the seat belt 21 measured by the seat belt detection sensor 22. Thereafter, the calculation result is output to the control unit .

[0046] In step S13, the heart rate value calculation unit 41 determines whether the magnitude (amount of movement) of the body surface movement of the occupant is within a certain range or not. That is, in step S13, the heart rate value calculation unit 41 determines whether the retracted amount and the withdrawn amount of the seat belt 21 exceed the cutoff threshold value (see FIG. 4(a)).

[0047] In step S13, if the heart rate value calculation unit 41 determines that the retracted and unretracted amounts of the seat belt 21 exceed the cutoff threshold (see FIG. 4(a)), the process proceeds to step S14. In step S14, measurement of the occupant's body surface movement is stopped. At this time, as shown in FIG. 4(b), the occupant's body surface movement (amount of movement) is large compared to the reference, making it difficult for the Doppler sensor 12 to measure the occupant's body surface movement. For this reason, the detection value related to the occupant's body surface movement corresponding to the section from time A to time B that exceeds the cutoff threshold is treated as an abnormal value and is excluded from the heart rate value calculation process. After that, this control is terminated.

[0048] On the other hand, if it is determined in step S13 by the heart rate value calculation unit 41 that the retracted and unretracted amounts of the seat belt do not exceed the cutoff thresholds (see FIG. 4(a)), the process proceeds to step S15. At this time, as shown in FIG. 4(b), the body surface movement (amount of movement) of the occupant is small compared to the reference, so that the Doppler sensor 12 can measure the body surface movement of the occupant.

[0049] In step S15, the body surface movement (amount of movement) of the occupant based on the retracted and unretracted amounts of the seat belt 21 is fed back to the control unit 40. After that, the process proceeds to step S16.

[0050] In step S16, noise related to the body surface motion (amount of movement) of the occupant is removed (canceled), and then the process proceeds to step S17.

[0051] In step S17, the body surface motion of the occupant is detected by the Doppler sensor 12. After that, the heart rate value calculation unit 41 calculates the heart rate value (estimated heart rate) of the occupant based on the detected value related to the body surface motion according to the flow shown in Fig. 3. Then, this control ends.

[0052] According to the embodiment described above, the following advantages (1) to (4) can be obtained.

[0053] (1) In the heart rate value calculation device 100 according to the above embodiment, on the condition that the retracted amount and the withdrawn amount of the seat belt 21 exceed the cutoff threshold (predetermined amount), the detection value related to the body surface motion corresponding to the time when the cutoff threshold is exceeded is regarded as an abnormal value and is excluded from the target of the heart rate value calculation process. According to the above embodiment, since the seat belt 21 is in close contact with the body of the occupant, the retracted amount and the withdrawn amount of the seat belt 21 caused by the body surface motion of the occupant can be directly detected. Therefore, by excluding the abnormal value in the body surface motion of the occupant from the target of the heart rate value calculation process, the abnormal value is prevented from affecting the heart rate value calculation process. This makes it possible to accurately calculate the heart rate value. Furthermore, according to the above embodiment, it is possible to determine whether to continue or stop measuring the heart rate value depending on the magnitude of the body surface motion of the occupant based on the retracted amount and the withdrawn amount of the seat belt 21, which contributes to ensuring the reliability of the heart rate value calculation. As a result, the body surface movement of the occupant can be detected with a simple configuration without providing a separate device for performing heart rate value calculation processing, so that the heart rate value calculation device 100 can be effectively used for heart rate value calculation.

[0054] (2) The heart rate value calculation device 100 according to the above embodiment is provided with a seat belt detection sensor 22 that detects the amount of retraction and withdrawal of the seat belt 21 caused by the body surface movement of the occupant. This makes it possible to easily detect the amount of retraction and withdrawal of the seat belt 21 caused by the body surface movement of the occupant using the seat belt detection sensor 22, and therefore to easily calculate the magnitude (amount of movement) of the body surface movement of the occupant.

[0055] (3) In the heart rate value calculation device 100 according to the above embodiment, the Doppler sensor 12 is configured by at least one of a radio wave Doppler sensor, an ultrasonic Doppler sensor, a piezoelectric sensor, and an air pressure sensor. This makes it possible to easily detect the body surface movement of the occupant by at least one of the radio wave Doppler sensor, the ultrasonic Doppler sensor, the piezoelectric sensor, and the air pressure sensor.

[0056] (4) In the heart rate value calculation device 100 according to the above embodiment, the Doppler sensor 12 is provided on at least one of the seat body 11, the headrest body 31, the steering wheel, and the instrument panel. By providing the Doppler sensor 12 on at least one of the seat body 11, the headrest body 31, and the steering wheel, the Doppler sensor 12 can be brought into contact with the body of the occupant to detect the body surface motion of the occupant, so that the body surface motion of the occupant can be directly detected. Also, by providing the Doppler sensor 12 on the instrument panel, the body surface motion of the occupant can be detected in a non-contact manner, so that the body surface motion of the occupant can be effectively detected even if the Doppler sensor 12 and the occupant are separated from each other.

[0057] (Modification) Next, a heart rate value calculation process according to a modified example of this embodiment will be described with reference to Fig. 6. In this modified example, a body surface motion detection process by the headrest pressure sensor 32 is further added to steps S10 to S12 in the heart rate value calculation process according to the above embodiment.

[0058] 6, in step S20, whether or not the head of the occupant is in contact with the headrest main body 31 when getting in is detected by the headrest pressure sensor 32. If the headrest pressure sensor 32 detects that the head of the occupant is in contact with the headrest main body 31 when getting in, a detection signal is output from the headrest pressure sensor 32 to the control unit 40.

[0059] The heart rate value calculation unit 41 of the control unit 40 sets the ground contact state of the occupant's head to the headrest main body 31 as the initial posture value, on the condition that the head of the occupant is in contact with the headrest main body 31. The process of step S20 is additionally executed to the process of step S10 in the above embodiment. This makes it possible to set a more accurate initial posture value. Then, the process proceeds to step S21.

[0060] In step S21, the headrest pressure sensor 32 detects whether or not the head of the occupant is in contact with the headrest main body 31 while driving. If the headrest pressure sensor 32 detects that the head of the occupant is in contact with the headrest main body 31 while driving, the headrest pressure sensor 32 outputs a detection signal to the control unit 40. Note that the process of step S21 is executed in addition to the process of step S11 in the above embodiment. Then, the process proceeds to step S22.

[0061] In step S22, the heart rate value calculation unit 41 of the control unit 40 calculates the magnitude (amount of movement) of the occupant's body surface movement based on the detection signal from the headrest pressure sensor 32. The process of step S22 is executed in addition to the process of step S12 in the above embodiment. This makes it possible to calculate the magnitude (amount of movement) of the occupant's body surface movement more accurately. Thereafter, the processes of steps S23 to S27 are executed. Note that steps S23 to S27 correspond to steps S13 to S27 described in the above embodiment, respectively, and have similar process contents.

[0062] (Other variations) The above embodiment can be modified as follows.

[0063] In the above embodiment, the seat belt is shown as an example of a restraining portion for restraining an occupant, but the present invention is not limited to this. In the present invention, a restraining portion other than a seat belt may be used as long as it is capable of restraining an occupant.

[0064] In the above embodiment, a seat belt detection sensor is shown as an example of an actuation amount detection unit that detects the actuation amount of a seat belt (restraint unit), but the present invention is not limited to this. In the present invention, an actuation amount detection unit other than a seat belt detection sensor may be used as long as it is capable of detecting the actuation amount of a seat belt (restraint unit).

[0065] In the above embodiment, an example in which the seat belt detection sensor is provided near the shoulder anchor is shown, but the present invention is not limited to this. In the present invention, if it is possible to detect the amount of operation of the seat belt (restraint portion), it is preferable to provide the seat belt detection sensor at a location other than the vicinity of the shoulder anchor.

[0066] In the above embodiment, an example was shown in which the detection value related to the body surface motion detected by the Doppler sensor is excluded as an abnormal value on the condition that the retracted amount and the unretracted amount of the seat belt exceed a predetermined value, but the present invention is not limited to this. For example, a frequency band to be excluded from the movement amount of the body surface motion may be estimated according to the retracted amount and the unretracted amount of the seat belt, and the frequency band may be excluded from the detection value related to the body surface motion detected by the Doppler sensor.

[0067] The above-described embodiments are merely examples of the application of the present invention, and it goes without saying that any other embodiments within the scope of the claims are also included in the technical scope of the invention. [Explanation of symbols]

[0068] 10: Seat section 11: Seat body 12: Doppler sensor (body surface motion detection unit) 13: Seat pressure sensor (body surface motion detection unit) 20: Seat belt section 21: Seat belt (restraint) 22: Seat belt detection sensor (operation amount detection section) 23: Seat buckle confirmation sensor 24: Shoulder anchor 30: Headrest section 31: Headrest body 32: Headrest pressure sensor (body surface motion detection unit) 40: Control section 41: Heart rate calculation section 100: Heart rate calculator

Claims

1. a body surface motion detection unit for detecting a body surface motion of an occupant; a heart rate value calculation unit that performs a heart rate value calculation process to calculate a heart rate value of the occupant based on a detection value related to the body surface motion detected by the body surface motion detection unit; A restraint section that restrains the occupant; an actuation amount detection unit that detects an actuation amount of the restraint unit; a headrest pressure sensor for detecting a change in pressure in response to a body surface movement of the head of an occupant; the heart rate value calculation unit, on condition that an actuation amount of the restraint unit exceeds a predetermined amount, excludes a detection value related to the body surface motion corresponding to a time when the actuation amount of the restraint unit exceeds the predetermined amount as an abnormal value from a target of the heart rate value calculation process; The restraint portion is a seat belt that can be retracted and withdrawn, The operation amount detection unit detects the amount of retraction and the amount of withdrawal of the seat belt, the heart rate value calculation unit, on the condition that the retracted amount and the unretracted amount of the seat belt exceed a predetermined amount, excludes a detection value related to the body surface motion corresponding to a time when the predetermined amount is exceeded from a target of the heart rate value calculation process as an abnormal value, a headrest pressure sensor for detecting whether or not the head of an occupant is in contact with a headrest body, and, if it is determined that the head is in contact with the headrest body, a process for setting the detection value of the headrest pressure sensor in the contact state as an initial posture value, and a process for calculating the magnitude of the occupant's body surface movement based on the detection signal from the headrest pressure sensor, are additionally executed in the determination process based on the retracted and unretracted amounts of the seat belt.

2. 2. The heart rate value calculation device according to claim 1, wherein the body surface motion detection unit is configured with at least one of a radio wave Doppler sensor, an ultrasonic Doppler sensor, a piezoelectric sensor, and an air pressure sensor.

3. 3. The heart rate calculation device according to claim 1, wherein the body surface motion detection unit is provided on at least one of a seat body, a steering wheel, and an instrument panel.

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