Sleeping posture collapse prevention method and sleeping posture collapse prevention device for occupant

Abstract

To provide a sleeping posture collapse prevention method and a sleeping posture collapse prevention device which can prevent a sleeping posture collapse of an occupant in sleeping.SOLUTION: A sleeping posture collapse prevention method of an occupant in a vehicle includes detecting biological information of an occupant, detecting whether the occupant falls in sleep on the basis of the biological information, and increasing the tension of a seat belt on the occupant.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a method and an apparatus for preventing an occupant from losing their posture while sleeping. [Background technology]

[0002] BACKGROUND ART There is known a device that, when a vehicle occupant is not in an appropriate seating position, causes the occupant to assume an appropriate seating position (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2017-185893 Summary of the Invention [Problem to be solved by the invention]

[0004] The occupant protection device described in Patent Document 1 wakes up a sleeping occupant by pressing the occupant's back, buttocks, etc. with a pressing device installed in the seat back or seat cushion, and encourages the occupant to change their head position to an appropriate position, but it cannot prevent the occupant from losing their posture while sleeping.

[0005] An object of the present invention is to provide a method and an apparatus for preventing a passenger from losing his / her posture while sleeping, which can prevent the passenger from losing his / her posture while sleeping. [Means for solving the problem]

[0006] One aspect of the present invention is a method for preventing a vehicle occupant from losing their posture while sleeping, which detects the occupant's biometric information, determines whether the occupant is asleep based on the biometric information, and increases the tension of the occupant's seat belt if it is determined that the occupant is asleep.

[0007] According to the above aspect, when it is determined that the occupant has fallen asleep, the tension of the seat belt of the occupant is increased, thereby preventing the occupant from losing his / her posture while sleeping. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a schematic diagram showing the configuration of a device for preventing poor posture during sleep according to an embodiment of the present invention; [Figure 2] FIG. 2 is a control block diagram of a controller. [Figure 3] 10 is a flowchart of control. [Figure 4] FIG. 10 is a diagram showing the posture of an occupant when the seat belt is retracted. [Figure 5] FIG. 10 is a diagram showing the posture of an occupant when the seat belt is not retracted. [Figure 6] FIG. 10 is a diagram showing a change in tension when the seat belt is retracted. [Figure 7] FIG. 10 is a diagram showing the state of the driver when releasing the seat belt. [Figure 8] FIG. 10 is a diagram showing a change in tension when the seat belt is released from its retracted state. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a schematic diagram showing the configuration of a device 1 for preventing a vehicle occupant from losing their sleeping posture. Here, the occupants who are the targets of the sleep posture prevention are occupants who are not driving the vehicle. That is, not only occupants sitting in the passenger seat or the back seat are targets of the sleep posture prevention, but also occupants sitting in the driver's seat of the vehicle can be targets of the sleep posture prevention if they are not driving the vehicle, for example, if they have stopped the vehicle and are taking a rest in the driver's seat, reading a book, or working.

[0010] The device 1 for preventing poor posture during sleep includes a biological information sensor 2, a seat belt retractor 3, a tension sensor 4, and a controller 5.

[0011] The biological information sensor 2 is provided in the vehicle and detects the biological information of the occupant. The biological information is information indicating whether the occupant is sleeping or not, and includes behavioral information such as the occupant's facial expression and the open / closed state of the eyelids, and physiological information such as the occupant's pulse wave, pulse rate, electrocardiogram, and brain waves. In this embodiment, the biological information sensor 2 includes a camera 21 and detects the open / closed state of the eyelids as the occupant's biological information from an image of the occupant captured by the camera 21. The biological information sensor 2 is, for example, housed in the dashboard 6 inside the vehicle or installed on the ceiling of the vehicle.

[0012] The seat belt retractor 3 includes an electric motor 31, which can retract and release a seat belt 32.

[0013] The tension sensor 4 includes a load cell, a strain gauge, etc., and detects the tension of the seat belt 32. In this embodiment, the tension sensor 4 is provided in the seat belt retractor 3.

[0014] The controller 5 controls the electric motor 31 to retract the seat belt 32 and to prevent the occupant from losing their posture while sleeping. The controller 5 is realized by, for example, a microcomputer equipped with a calculation unit such as a CPU or GPU, a storage unit such as a ROM or RAM, and an input / output unit such as an input / output interface. The biological information sensor 2, the tension sensor 4, and the electric motor 31 are electrically or communicatively connected to the controller 5.

[0015] FIG. 2 is a control block diagram of the controller 5. As shown in FIG. 2, the controller 5 includes a storage unit 51, a sleep determination unit 52, and a winding control unit 53.

[0016] The memory unit 51 stores a computer program for causing the controller 5 to function, various maps used for control, various threshold values, etc. The map stored in the memory unit 51 includes, for example, a map that defines command values for the electric motor 31 that change the tension of the seat belt 32 over a predetermined time period when winding up or releasing the seat belt 32.

[0017] The sleep determination unit 52 determines whether the occupant is asleep or not. In this embodiment, the sleep determination unit 52 determines whether the occupant is asleep or not based on the open / closed state of the occupant's eyelids and the tension of the seat belt 32.

[0018] The winding control unit 53 controls winding and releasing of the seat belt 32 based on the determination result of the sleep determination unit 52.

[0019] 3 is a flowchart of the control executed by the controller 5. The control routine shown in the flowchart is pre-programmed, and this program is installed in the controller 5. In accordance with the program, the controller 5 repeatedly executes the following control routine at an operation cycle of, for example, about 10 milliseconds.

[0020] 3, the controller 5 acquires the outputs of the biological information sensor 2 and the tension sensor 4, i.e., the captured image including the open / closed state of the occupant's eyelids and the tension of the seat belt 32. In the following step S2, the sleep determination unit 52 determines whether the sleep flag is set. If it is determined in step S2 that the sleep flag is not set, the process proceeds to step S3; otherwise, the process proceeds to step S8.

[0021] In step S3, the sleep determination unit 52 determines whether the occupant's eyelids have been closed for a predetermined period of time based on the open / closed state of the occupant's eyelids obtained from the captured image. The predetermined period of time here is, for example, 10 seconds. If it is determined in step S3 that the occupant's eyelids have been closed for the predetermined period of time, the process proceeds to step S4; otherwise, the process returns to step S1.

[0022] In step S4, the sleep determination unit 52 determines whether the state in which the amount of change in tension of the seat belt 32 is equal to or less than the threshold has continued for a predetermined time based on the tension of the seat belt 32 acquired from the tension sensor 4. If it is determined in step S4 that the state in which the amount of change in tension is equal to or less than the threshold has continued for the predetermined time, the sleep determination unit 52 determines that the occupant is asleep and sets a sleep flag in step S5, but if not, the process returns to step S1.

[0023] If it is determined that the occupant is asleep, in step S6, the retraction control unit 53 sends a command to the electric motor 31 to retract the seat belt 32 and increase its tension, as shown in Fig. 4. This maintains the posture of the occupant in the state it was in when it went to sleep. This prevents the occupant from losing their sleeping posture as shown in Fig. 5, and prevents muscle fatigue due to poor posture.

[0024] When winding up the seat belt 32, the winding control unit 53 increases the tension to a predetermined level that prevents the occupant from losing their posture without disturbing their sleep. The predetermined tension is, for example, 20 to 40 N. 20 to 40 N is a value obtained by converting the load of a weighted blanket that promotes sound sleep into the tension of the seat belt 32, and produces a sound sleep effect similar to that of a pressure blanket.

[0025] The retraction control unit 53 also increases the tension of the seat belt 32 as shown in FIG. 6. That is, the retraction control unit 53 increases the tension of the seat belt 32 so that the increasing speed of the tension gradually increases from the start of increasing the tension of the seat belt 32 until a first increase time TU1 (as a first time) has elapsed, increases the tension at a constant speed until a second increase time TU2 (as a second time) has elapsed after the first increase time TU1 has elapsed, and increases the tension so that the increasing speed of the tension gradually slows down until a third increase time TU3 (as a third time) has elapsed after the second increase time TU2 has elapsed. This prevents the tension of the seat belt 32 from being suddenly increased, thereby preventing the occupant from being suddenly tightened and from feeling uncomfortable. The third increase time TU3 is the time when the seat belt 32 reaches a predetermined tension TF2.

[0026] In this embodiment, as shown in Fig. 6, the tension is increased in a quadratic curve until the first increase time TU1 has elapsed, and until the third increase time TU3 has elapsed after the second increase time TU2 has elapsed. The first increase time TU1, second increase time TU2, and third increase time TU3 can be, for example, 1 second, 2 seconds, or 3 seconds. In the tension change shown in Fig. 6, the tension is increased in a quadratic curve in the first second to 20% of the change amount ΔTF from the original tension TF1 to the predetermined tension TF2 after winding. The tension is then increased linearly in the next second to 80% of the change amount ΔTF. The tension is then increased in a quadratic curve in the final second to 100% of the change amount ΔTF, i.e., to the predetermined tension TF2.

[0027] 3, in step S7 following step S6, the retraction control unit 53 determines whether or not retraction of the seat belt 32 is complete. In step S7, if it is determined that the seat belt 32 has been retracted to the predetermined tension TF2 and retraction is complete, the process returns to step S1; otherwise, the process of retracting the seat belt 32 continues in step S6.

[0028] On the other hand, if it is determined in step S2 of Fig. 3 that the sleep flag is set, processing related to unwinding the seat belt 32 is performed in step S8 and subsequent steps. That is, the sleep determination unit 52 first determines in step S8 whether the eyelids have remained open for a predetermined time. Here, the predetermined time is, for example, 10 seconds. If it is determined in step S8 that the eyelids have remained open for the predetermined time, the sleep determination unit 52 determines that the occupant has woken up from sleep and resets the sleep flag in step S10; otherwise, the process proceeds to step S9.

[0029] Here, there are cases where the occupant has their eyelids closed but is not asleep, for example, when they are thinking with their eyes closed. In such cases, it is preferable that the occupant be able to release the retraction of the seat belt 32. Therefore, in this embodiment, as shown in Fig. 7, when the occupant pulls on the seat belt 32 and the tension exceeds a release threshold, the retraction of the seat belt 32 is released.

[0030] 3, the sleep determination unit 52 determines whether the tension of the seat belt 32 exceeds the release threshold. The release threshold is, for example, 50 N. If it is determined in step S9 that the tension exceeds the release threshold, the sleep determination unit 52 determines that the occupant has woken up from sleep and resets the sleep flag in step S10; otherwise, the process returns to step S1.

[0031] If it is determined as a result of the processing in steps S8 to S10 that the occupant has woken up, in step S11 the retraction control unit 53 sends a command to the electric motor 31 to release the retraction of the seat belt 32, and loosens the seat belt 32 until it returns to the original tension TF1 before retraction. This releases the increased tension of the seat belt 32, making it easier for the occupant to move their body.

[0032] Here, when releasing the retraction of the seat belt 32, the retraction control unit 53 reduces the tension of the seat belt 32 as shown in Fig. 8. That is, the retraction control unit 53 reduces the tension of the seat belt 32 so that the rate of reduction gradually increases from the start of reducing the tension until a first reduction time TD1 has elapsed, reduces the tension at a constant rate until a second reduction time TD2 has elapsed after the first reduction time TD1 has elapsed, and reduces the tension so that the rate of reduction gradually slows down until a third reduction time TD3 has elapsed after the second reduction time TD2 has elapsed. This prevents the tension of the seat belt 32 from being suddenly reduced, preventing the occupant from suddenly being released from the fastening, and preventing the occupant from feeling uncomfortable.

[0033] In this embodiment, as shown in Fig. 8, the tension is decreased in a quadratic curve until the first decrease time TD1 has elapsed, and until the third decrease time TD3 has elapsed after the second decrease time TD2 has elapsed. The first decrease time TD1, second decrease time TD2, and third decrease time TD3 can be, for example, 1 second, 2 seconds, or 3 seconds. In the case of the tension change shown in Fig. 8, the tension is decreased in a quadratic curve to 20% of the change amount ΔTF from the predetermined tension TF2 to the original tension TF1 before winding in the first second, then linearly decreased to 80% of the change amount ΔTF in the next second, and then decreased in a quadratic curve to 100% of the change amount ΔTF, i.e., back to the original tension TF1, in the final second.

[0034] 3, in step S12 following step S11, the retraction control unit 53 determines whether or not the retraction and release of the seat belt 32 is complete. In step S12, if it is determined that the seat belt 32 has returned to the original tension TF1 before retraction and the retraction is complete, the process returns to step S1; otherwise, the process of retracting and release of the seat belt 32 continues in step S11.

[0035] According to the above embodiment, when it is determined that the occupant has fallen asleep, the tension of the occupant's seat belt 32 is increased, thereby preventing the occupant from losing his / her posture while sleeping.

[0036] As described above, the best configurations, methods, and the like for implementing the present invention have been disclosed in the above description, but the present invention is not limited thereto. That is, although the present invention has been particularly illustrated and described mainly with reference to specific embodiments, those skilled in the art can make various modifications to the above-described embodiments in terms of shape, material, quantity, and other detailed configurations without departing from the scope of the technical idea and purpose of the present invention. Furthermore, the above-disclosed descriptions limiting the shape, material, and the like are provided as examples to facilitate understanding of the present invention and are not intended to limit the present invention. Therefore, descriptions using names of components that are free from some or all of the limitations on shape, material, and the like are included in the present invention.

[0037] The biological information sensor 2 may include, for example, a pulse wave sensor, a pulse rate sensor, an electrocardiogram sensor, an electroencephalogram sensor, or the like instead of or in addition to the camera 21, and may detect the biological information of the occupant using any one or more of these. The biological information sensor 2 may be installed, for example, on the dashboard 6, on the vehicle's rearview mirror, or behind the driver's seat or passenger seat.

[0038] The seat belt retractor 3 may retract and release the seat belt 32 using, for example, a pneumatic motor or a hydraulic motor, or may increase the tension by pulling the seat belt 32 with a linear motor.

[0039] The tension sensor 4 may detect the tension of the seat belt 32 from the torque of the electric motor 31, for example, or may directly detect the tension by contacting or not contacting the seat belt 32. The tension sensor 4 does not have to be provided in the seat belt retractor 3, and may be provided at an intermediate position of the seat belt 32, for example.

[0040] In the controller 5, the sleep determination unit 52 may determine whether the occupant is asleep based only on the open / closed state of the eyelids, or may determine only on the tension of the seat belt 32. The sleep determination unit 52 may also determine whether the occupant is asleep based on biological information such as the occupant's pulse wave, pulse rate, electrocardiogram, and electroencephalogram.

[0041] The winding control unit 53 may change the tension of the seat belt 32 linearly from the start of increasing or decreasing the tension of the seat belt 32 until the first increase time TU1 and the first decrease time TD1 have elapsed, or at least from the time the second increase time TU2 and the second decrease time TD2 are exceeded until the third increase time TU3 and the third decrease time TD3 have elapsed, or may change the tension of the seat belt 32 in a quadratic curve from the time the first increase time TU1 and the first decrease time TD1 are exceeded until the second increase time TU2 and the second decrease time TD2 have elapsed. [Explanation of symbols]

[0042] 1...sleep posture prevention device, 2...biometric information sensor (sensor), 3...seat belt winding device, 4...tension sensor, 5...controller, 32...seat belt, TU1...first increase time (first hour), TU2...second increase time (second hour), TU3...third increase time (third hour).

Claims

1. A method for preventing a vehicle occupant from losing their sleeping posture, comprising: Detecting biological information of the occupant; A method for preventing posture from being disrupted during sleep, which determines whether the occupant has fallen asleep based on the biological information, and increases the tension of the occupant's seat belt if it is determined that the occupant has fallen asleep.

2. 2. The method for preventing poor posture during sleep according to claim 1, increasing the tension of the seat belt so that the rate of increase of the tension gradually increases until a first time period has elapsed since the tension of the seat belt started to be increased; increasing the tension at a constant rate beyond the first time until a second time has elapsed; The method for preventing poor posture during sleep comprises increasing the tension so that the rate of increase in the tension gradually slows down until a third time has elapsed after the second time has elapsed.

3. 3. The method for preventing poor posture during sleep according to claim 1 or 2, The method for preventing the occupant from losing his / her posture while sleeping releases the increased tension of the seat belt when it is determined that the occupant has woken up from sleep.

4. 3. The method for preventing poor posture during sleep according to claim 1 or 2, The method for preventing the occupant from losing his / her posture while sleeping increases the tension of the seat belt to a level that does not disturb the occupant's sleep when it is determined that the occupant has fallen asleep.

5. 3. The method for preventing poor posture during sleep according to claim 1 or 2, taking an image of the occupant; A method for preventing a passenger from losing his / her posture while sleeping, the method determining whether the passenger is asleep or not based on the passenger's biological information obtained by the imaging.

6. 6. The method for preventing poor posture during sleep according to claim 5, Detecting the tension of the seat belt; The method for preventing the occupant from losing his / her posture while sleeping determines that the occupant has fallen asleep when the amount of change in tension of the seat belt remains below a threshold value for a predetermined period of time.

7. A device for preventing a vehicle occupant from losing their posture while sleeping, comprising: a sensor for detecting biological information of the occupant; A device for preventing posture loss during sleep that is equipped with a controller that determines whether the occupant is asleep based on the biometric information, and increases the tension of the occupant's seat belt if it is determined that the occupant is asleep.

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