Motion sickness detection device and motion sickness detection method

Abstract

To provide a motion sickness detection device and method that contribute to prevention or early countermeasures for motion sickness.SOLUTION: A motion sickness detection device detects that a vehicle is traveling in a second driving state where the lateral acceleration falls below the predetermined acceleration after traveling in a first driving state where the lateral acceleration acting on a passenger exceeds the predetermined acceleration. When the device detects that the vehicle is traveling in the second driving state after traveling in the first driving state, the device determines the progress level of motion sickness in the passenger (S304-S307) on the basis of the head posture of the passenger detected in each of the first driving state and the second driving state, and generates a prescribed instruction signal on the basis of the progress level of motion sickness.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present invention relates to a motion sickness detection device and a motion sickness detection method. [Background technology]

[0002] There is technology that detects whether a passenger is suffering from motion sickness based on the passenger's biological information, such as an electrocardiogram, breathing, and sweating (Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 4882433 Summary of the Invention [Problem to be solved by the invention]

[0004] Biometric information fluctuates due to various factors other than motion sickness, so a detection result based on the biological information does not necessarily provide an accurate indication that a passenger is suffering from motion sickness.

[0005] On the other hand, it is desirable to alert passengers to the risk of motion sickness before the symptoms of motion sickness actually appear or while the motion sickness that has developed is still relatively mild, leading to prevention or early countermeasures against motion sickness.

[0006] In view of the above circumstances, the present invention aims to provide a motion sickness detection device and a motion sickness detection method that are capable of determining whether a passenger is in a situation in which he or she is likely to develop motion sickness based on the driving state of the vehicle, and that contribute to the prevention of motion sickness or the realization of early countermeasures against motion sickness. [Means for solving the problem]

[0007] In order to solve the above-mentioned problems, a motion sickness detection device according to one embodiment of the present invention comprises a driving state detection means for detecting that, after driving in a first driving state in which the lateral acceleration applied to a occupant is equal to or greater than a predetermined acceleration, the vehicle is currently driving in a second driving state in which the lateral acceleration is less than the predetermined acceleration, a head posture detection means for detecting the head posture of the occupant, a progression degree determination means for determining the progression degree of motion sickness in the occupant based on the head posture of the occupant detected by the head posture detection means in each of the first driving state and the second driving state when the driving state detection means detects that the vehicle is currently driving in the second driving state after driving in the first driving state, and a signal generation means for generating a predetermined instruction signal based on the progression degree of the motion sickness determined by the progression degree determination means.

[0008] A motion sickness detection method according to another embodiment of the present invention detects a first head posture of the occupant while driving in a first driving state in which the lateral acceleration applied to the occupant is equal to or greater than a predetermined acceleration, and detects a second head posture of the occupant while driving in the second driving state in which the lateral acceleration is less than the predetermined acceleration after driving in the first driving state, and determines whether the occupant is experiencing signs of motion sickness based on the first head posture and the second head posture while driving in the second driving state. Effect of the Invention

[0009] According to the present invention, when the occupant is in a head posture that promotes the onset of motion sickness, it is determined that the occupant has a sign of motion sickness, based on both the occupant's head posture when a lateral acceleration of a predetermined level or more is applied and the head posture after the lateral acceleration is released. This makes it possible to suppress the onset of motion sickness by issuing a warning before the occupant actually experiences symptoms of motion sickness, such as discomfort or poor physical condition, or to take measures while the symptoms are still relatively mild, thereby slowing down the progression of the symptoms. [Brief description of the drawings]

[0010] [Figure 1] 1 is a schematic diagram showing a schematic configuration of a motion sickness detection device according to an embodiment of the present invention; [Diagram 2] FIG. 2 is a schematic diagram showing an internal configuration of a control unit of the motion sickness detection device. [Diagram 3] 11 is a flowchart showing an overall flow of a motion sickness detection process. [Figure 4] 13 is a flowchart showing the contents of an illusion amount calculation process (during turning). [Diagram 5] 13 is a flowchart showing the contents of an illusion amount calculation process (when driving straight after turning). [Figure 6] 13 is a flowchart showing the contents of advance guidance processing. [Figure 7] FIG. 11 is an explanatory diagram showing classification of head poses according to rotation axes. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0012] (Overall configuration of the motion sickness detection device) FIG. 1 shows a schematic configuration of a motion sickness detection device 1 according to one embodiment of the present invention.

[0013] The motion sickness detection device 1 according to the present embodiment is mounted on a vehicle and determines whether a passenger is in a situation where he or she is likely to develop motion sickness (so-called motion sickness) while traveling, and when the passenger is in such a situation, warns the passenger against motion sickness. This makes it possible to suppress the onset of motion sickness itself, or to take measures while the symptoms are still relatively mild even if the symptoms of motion sickness have appeared, thereby slowing down the progression of the symptoms. Whether or not a passenger is in a situation where he or she is likely to develop motion sickness is basically determined based on the driving state of the vehicle.

[0014] Specifically, after a passenger experiences a state in which a lateral acceleration of a predetermined level or more is applied to the body, particularly the head, and then this lateral acceleration is resolved, the passenger is judged to be in a state in which the passenger is likely to experience a kinesthetic illusion, which is a precursor to motion sickness, and is likely to develop motion sickness. The passenger's sensitivity to kinesthetic illusion, in other words, the strength of the kinesthetic illusion that the passenger actually feels, is highly dependent on the passenger's posture in that state, particularly the head posture. Therefore, the head posture of the passenger when the passenger is subjected to a lateral acceleration of a predetermined level or more and the head posture after the lateral acceleration is resolved are detected, and based on both of these postures, if the passenger is in a head posture that promotes the onset of motion sickness, it is determined that the passenger has a premonition of motion sickness, and guidance is provided to the passenger.

[0015] The motion sickness detection device 1 includes a control unit 101, various sensors 201 to 203 related to the detection of motion sickness, and further includes an HMI (human machine interface) device 301.

[0016] The control unit 101 constitutes the calculation section of the motion sickness detection device 1, and in this embodiment, the control unit 101 can be embodied as an electronic control unit equipped with a central processing unit (CPU), an input / output interface, and various memory units such as ROM, RAM, etc.

[0017] In this embodiment, the vehicle is equipped with an in-vehicle camera 201, a vehicle speed sensor 202, and a steering angle sensor 203. These various sensors 201, 202, and 203 constitute a detection unit of the motion sickness detection device 1.

[0018] The in-vehicle camera 201 is a camera for monitoring the inside of the vehicle, and can capture the entire interior of the vehicle (hereinafter referred to as the "vehicle compartment"). The in-vehicle camera 201 captures the driver and other passengers, and outputs the image information to the control unit 101. The control unit 101 can detect the posture or direction of the upper body of the passenger, particularly the head, based on the image information acquired from the in-vehicle camera 201. Furthermore, the control unit 101 can also detect the direction of the passenger's line of sight (hereinafter referred to as the "line of sight direction") based on the image information acquired from the in-vehicle camera 201. In addition to the above, in this embodiment, the seating position of the passenger, that is, the position of the seat in which the passenger is seated, is detected. The in-vehicle camera 201 can capture the entire vehicle compartment, for example, by being built into or attached to a case of a rearview mirror or a room mirror provided in the vehicle compartment.

[0019] The vehicle speed sensor 202 detects the traveling speed of the vehicle (hereinafter referred to as "vehicle speed") VSP. The vehicle speed VSP is detected, for example, by detecting the rotation speeds of the front and rear wheels of the vehicle, i.e., the driving wheels and the driven wheels, and averaging the rotation speeds of the front wheels and the rear wheels.

[0020] The steering angle sensor 203 detects the direction of the front wheels relative to the straight-ahead direction of the vehicle, that is, the direction of the steering wheels (hereinafter referred to as "steering angle") θstr. The steering angle θstr is detected by converting the rotation angle of the steering wheel provided at the driver's seat into the operation angle of the front wheels.

[0021] Both the vehicle speed VSP detected by the vehicle speed sensor 202 and the steering angle θstr detected by the steering angle sensor 203 are output to the control unit 101. The vehicle speed VSP and the steering angle θstr are indicators of the driving state of the vehicle, and the control unit 101 determines the driving state of the vehicle based on the vehicle speed VSP and the steering angle θstr.

[0022] When the passenger has a sign of motion sickness, the HMI device 301 operates in response to an instruction signal output from the control unit 101 to provide guidance to alert the passenger to motion sickness. This guidance may be visual or auditory. For example, a warning light or speaker may be used as the HMI device 301, and the warning light may be turned on or audio information containing a warning may be output from the speaker. Alternatively, the HMI device 301 may be embodied as a display device that can be linked to the in-vehicle navigation device 211 described below, and guidance may be displayed as visual information such as characters or symbols.

[0023] In addition to the above, the motion sickness detection device 1 can operate in cooperation with an in-vehicle navigation device 211 provided in the vehicle.

[0024] The in-vehicle navigation device 211 stores road map information in advance and can display a road map on a display device (not shown). Furthermore, the in-vehicle navigation device 211 allows the driver to set a target point for the vehicle, searches for a driving route from the current position to the target position based on the current position and the target position of the vehicle, and displays the searched driving route on a road map. The driving route can be changed as appropriate by the driver's selection. The control unit 101 cooperates with the in-vehicle navigation device 211 to determine road characteristics of the driving route. Then, when the driving route includes a section in which the passenger is likely to develop motion sickness, that is, a situation in which the passenger is likely to experience a kinetic illusion, the control unit 101 operates the HMI device 301 to provide guidance to the passenger (hereinafter, this is particularly referred to as "advance guidance" to distinguish it from "guidance" provided when the passenger has a sign of motion sickness). In this embodiment, the advance guidance is a correction of posture, particularly head posture.

[0025] (Internal structure of the control unit) FIG. 2 is a schematic diagram showing the internal configuration of the control unit 101.

[0026] In this embodiment, passengers other than the driver are considered to be "passengers" who are targets of motion sickness detection. Passengers include passengers sitting in the passenger seat next to the driver's seat, as well as passengers sitting in the rear seats behind the driver's seat. Not limited to this, it is also possible to include the driver in addition to passengers as passengers.

[0027] The driving state detection unit 111 detects a situation in which a passenger is likely to develop motion sickness, specifically, a driving state in which the lateral acceleration applied to the passenger is equal to or greater than a predetermined acceleration, followed by a driving state in which the lateral acceleration applied to the passenger decreases to less than the predetermined acceleration. In this embodiment, based on the output information of the vehicle speed sensor 202 and the steering angle sensor 203, it detects that the vehicle is traveling straight or close to straight (hereinafter referred to as "straight traveling") following a turning run at a vehicle speed equal to or greater than a predetermined speed.

[0028] Head posture detection unit 112 detects the head posture of passenger P based on the output information of in-vehicle camera 201.

[0029] FIG. 7 shows the head posture of the occupant P to be detected in this embodiment. In this embodiment, the head posture shown in FIG. 7(a) (hereinafter referred to as the "basic posture") is used as the basis, and the head posture shown in FIG. 7(b) is classified as the "twisted posture", and the head posture shown in FIG. 7(c) is classified as the "tilted posture", which are detected by the head posture detection unit 112. In the basic posture, the head of the occupant P faces forward, in the twisted posture, the head is rotated around the vertical axis (also called the yaw axis) Ay, and in the tilted posture, the head is rotated around the front-rear axis (also called the roll axis) Ar. The rotation angle of the head in the twisted posture is called the "head yaw angle" Hy, and the rotation angle of the head in the tilted posture is called the "head roll angle" Hr.

[0030] The gaze direction detection unit 113 detects the gaze direction of the passenger based on the output information of the in-car camera 201.

[0031] The situation determination unit 114 determines the vehicle exterior information acquisition situation of the passenger. Specifically, when the vehicle exterior information can be acquired through an opening of the vehicle, for example, a window, for example, when a large window is present and the scenery outside the vehicle can be seen, and sufficient visibility outside the vehicle can be secured, the vehicle exterior information acquisition situation is determined to be good. On the other hand, when there is no window, or even if there is a window, it is small and the visibility outside the vehicle is narrow, the vehicle exterior information acquisition situation is determined to be poor. It is possible to determine that the vehicle exterior information acquisition situation is good for a passenger sitting in the passenger seat, and that the vehicle exterior information acquisition situation is poor for a passenger sitting in the rear seat where the vehicle body or pillars are in the way and the visibility is entirely or partially blocked.

[0032] The progression degree determination unit 115 determines the progression degree of motion sickness in the passenger when the passenger is in a situation where the passenger is likely to develop motion sickness, that is, when the passenger is driving in a state where the lateral acceleration of a predetermined level or more is applied to the passenger and then the lateral acceleration is eliminated, specifically, when the passenger is driving straight after turning. Here, the head posture of the passenger while driving in a state where the lateral acceleration of a predetermined level or more is applied and the head posture while driving in a state where the lateral acceleration is eliminated are detected, and both of these head postures are reflected in the determination of the progression degree. In addition, in this embodiment, the line of sight direction of the passenger while driving in a state where the lateral acceleration of a predetermined level or more is applied is detected, and this is also reflected in the determination of the progression degree.

[0033] The guidance information generating unit 116 generates guidance information to alert the passenger to motion sickness based on the progression of the motion sickness, and outputs this to the HMI device 301 as an instruction signal.

[0034] In this embodiment, the illusion amount Iv is calculated as a reference value indicating the progression degree of motion sickness, and the illusion amount Iv calculated each time the passenger experiences a situation where the passenger is likely to develop motion sickness, specifically, a straight driving after a turn for a predetermined time, is sequentially added to calculate a cumulative value Rm of the illusion amount Iv (progression degree determination unit 115). When the cumulative value Rm reaches a predetermined threshold value X1, it is determined that the passenger may develop motion sickness in the future or may already have developed motion sickness, and an instruction signal is output to the HMI device 301 to provide guidance to the passenger (guidance information generation unit 116). The illusion amount Iv is calculated as a different value depending on the passenger's head posture, line of sight direction, and outside information acquisition state while driving in a state where a lateral acceleration of a predetermined level or more is applied, and further the head posture while driving in a state where the lateral acceleration is eliminated.

[0035] The driving route determination unit 117 determines whether the vehicle's driving route set by the in-vehicle navigation device 211, i.e., the route the vehicle is scheduled to travel, contains any sections in which passengers may be prone to developing motion sickness, specifically, any sections in which a straight road continues on a long curved road that takes a considerable amount of time to pass through.

[0036] When a section exists on the vehicle's travel route where the passenger may be susceptible to motion sickness, the advance guidance information generator 118 operates the HMI device 301 to provide advance guidance to the passenger. In this embodiment, the head posture of the passenger is detected at that time, and when the current head posture has a large effect on the intensity of the kinesthetic illusion, the advance guidance prompts the passenger to change the head posture.

[0037] When the occupant maintains the head posture before the advance guidance even after the advance guidance is implemented, the driving state control unit 119 forcibly controls the driving state of the vehicle so as to reduce the kinetic illusion caused to the occupant when actually traveling through the above-mentioned section. For example, the vehicle speed VSP is reduced before entering the curved road, and the lateral acceleration applied to the occupant while traveling on the curved road is reduced.

[0038] (Motion sickness detection process) 3 is a flowchart showing an overall flow of the motion sickness detection process. In this embodiment, the motion sickness detection process is executed by the control unit 101 at a predetermined cycle.

[0039] In S101, various types of sensor information, such as output information from the in-vehicle camera 201, are acquired.

[0040] In S102, the amount of illusion Iv is calculated. The amount of illusion Iv is calculated according to the procedure shown in the flowchart of FIG.

[0041] In S103, it is determined whether the illusion amount Iv is greater than 0, in other words, whether the passenger experienced a ride in a state where the passenger was prone to motion sickness and experienced a kinetic illusion. If the illusion amount Iv is greater than 0, the process proceeds to S104, and if it is 0, the process proceeds to S105.

[0042] In S104, the newly calculated illusion amount Iv is added to the cumulative value Rm of the illusion amount Iv, and the cumulative value Rm is updated. Rm = Rm + Iv … (1)

[0043] In S105, the accumulation amount Rm is decreased. That is, since the passenger is not in a situation where he or she is likely to develop motion sickness, the accumulation of the kinesia in the passenger is deemed to have been partially eliminated, and the accumulation amount Rm is decreased. The amount of decrease in the accumulation amount Rm per control cycle can be set appropriately, and in this embodiment, it is calculated as a function of the current accumulation amount Rm. Rm = Rm - f(Rm) … (2)

[0044] In S106, it is determined whether the cumulative value Rm is equal to or greater than a predetermined threshold value X1. If the cumulative value Rm is equal to or greater than the predetermined threshold value X1, the process proceeds to S107, and if the cumulative value Rm is less than the threshold value X1, the process returns to S101 and the processes from S101 to S106 are repeated.

[0045] In S107, the passenger is informed that the passenger may develop motion sickness in the future or may already have developed motion sickness, and is advised to be careful about motion sickness. The content of the advice and the level of the advice can be changed according to the cumulative value Rm. For example, if the passenger is not currently experiencing any symptoms and has not yet developed motion sickness, but is informed that there is a possibility that motion sickness may develop in the future, audio information is provided to the passenger urging them to take a break because there is a possibility that motion sickness may develop.

[0046] (Contents of the illusion amount calculation process) FIG. 4 is a flowchart showing the contents of the illusion amount calculation process (when turning).

[0047] In S201, the vehicle speed VSP and the steering angle θstr are read.

[0048] In S202, it is determined whether the vehicle speed VSP is equal to or greater than a predetermined threshold value VSP1. If the vehicle speed VSP is equal to or greater than the predetermined threshold value VSP1, the process proceeds to S203, and if the vehicle speed VSP is less than the threshold value VSP1, the process proceeds to S209.

[0049] In S203, it is determined whether the steering angle θstr is equal to or greater than a predetermined threshold θ1. If the steering angle θstr is equal to or greater than the predetermined threshold θ1, the process proceeds to S204, and if it is less than the threshold θ1, the process proceeds to S209. In S202 and S203, it is determined whether the vehicle is traveling in a driving state in which the lateral acceleration applied to the passenger is equal to or greater than a predetermined acceleration, as a preliminary step to a situation in which the passenger is likely to develop motion sickness.

[0050] In S204, the head posture of the occupant during turning is detected by detecting the head rotation angle Hr about the longitudinal axis Ar (i.e., head roll angle), and the head rotation angle Hy about the vertical axis Ay (i.e., head yaw angle).

[0051] In S205, the line of sight direction angle Ae of the passenger is detected. In this embodiment, the line of sight direction angle Ae is the magnitude of the angle that the line of sight direction of the passenger makes with the horizontal direction.

[0052] In S206, it is determined whether the steering angle θstr is less than a predetermined threshold θ1, in other words, whether the vehicle has transitioned from a turning state in which the vehicle speed VSP is equal to or greater than the predetermined threshold VSP1 and the steering angle θstr is equal to or greater than the predetermined threshold θ1 to a straight-ahead state in which the steering angle θstr has decreased and is less than the threshold θ1. Only when the steering angle θstr is less than the predetermined threshold θ1, the process proceeds to S207, and otherwise it is determined that the turning state is continuing and the process returns to S201.

[0053] In S207, the duration TIM of the turning movement during which the vehicle speed VSP is equal to or greater than a predetermined threshold VSP1 and the steering angle θstr is equal to or greater than a predetermined threshold θ1 is measured, and it is determined whether this duration TIM is longer than a predetermined time T1, in other words, whether the turning movement has continued for a time longer than the predetermined time T1. If the duration TIM is longer than the predetermined time T1, the process proceeds to S208, and if it is within the time T1, that is, if the curved road is short and the turning movement is completed within a short time, the process proceeds to S209.

[0054] In S208, the amount of illusion Iv is calculated according to the procedure shown in the flowchart of FIG.

[0055] In S209, the illusion amount Iv is set to 0 (zero value). If the vehicle speed VSP when traveling on a curved road is low, the steering angle θstr is small, or the curved road is short, the passenger is not in a situation where he or she is likely to develop motion sickness, and no kinetic illusion is occurring to the passenger, so the illusion amount Iv is set to 0.

[0056] FIG. 5 is a flowchart showing the contents of the illusion amount calculation process (when driving straight after turning).

[0057] In S301, the head roll angle Hr' when traveling straight after turning is detected.

[0058] In S302, the vehicle exterior information acquisition status of the passenger is determined. If the vehicle exterior information acquisition status is good, such as if the passenger is seated in the passenger seat, the process proceeds to S308, and if the vehicle exterior information acquisition status is not good, such as if the passenger is seated in the rear seat, the process proceeds to S303.

[0059] In S303, it is determined whether the line of sight direction angle Ae of the passenger detected during turning is less than a predetermined threshold A1 and the passenger's line of sight during turning is downward. If the line of sight direction angle Ae of the passenger is less than the predetermined threshold A1, the process proceeds to S304, and if it is equal to or greater than the threshold A1, that is, if the passenger's line of sight during turning is facing forward or upward, the process proceeds to S308.

[0060] In S304, it is determined whether the head roll angle Hr detected during turning is greater than a predetermined threshold H1, in other words, whether the occupant rotated his / her head around the longitudinal axis Ar through an angle Hr exceeding the threshold H1 in response to the lateral acceleration applied during turning. If the head roll angle Hr during turning is greater than the predetermined threshold H1, the process proceeds to S307, and if it is equal to or less than the threshold H1, the process proceeds to S305.

[0061] In S305, it is determined whether the head yaw angle Hy detected during turning is greater than a predetermined threshold H2, in other words, whether the occupant has rotated his / her head around the vertical axis Ay through an angle Hy exceeding the threshold H2 in response to the lateral acceleration applied during turning. If the head yaw angle Hy during turning is greater than the predetermined threshold H2, the process proceeds to S306, and if it is equal to or less than the threshold H2, the process proceeds to S308.

[0062] In S306, it is determined whether the head roll angle Hr' during straight driving is greater than a predetermined threshold H1, in other words, whether the head, which was rotated about the vertical axis Ay during turning, is now rotated about the longitudinal axis Ar during straight driving (in other words, whether the axis about which the head is rotated is changed before and after the transition from turning to straight driving). If the head roll angle Hr' is greater than the predetermined threshold H1, the process proceeds to S308, and if it is equal to or less than the threshold H1, the process proceeds to S310.

[0063] In S307, it is determined whether the head roll angle Hr' during straight driving is equal to or smaller than a predetermined threshold H1, in other words, whether the head that has been rotated about the longitudinal axis Ar during turning is corrected after the transition to straight driving and the head is in an upright position. If the head roll angle Hr' is equal to or smaller than the predetermined threshold H1, the process proceeds to S309, and otherwise, that is, if the head rotation about the longitudinal axis Ar is maintained even after the transition to straight driving, the process proceeds to S310.

[0064] In S308, a relatively small first illusion amount Iv1 is calculated as the illusion amount Iv.

[0065] In S309, a second illusion amount Iv2 larger than the first illusion amount Iv1 is calculated as the illusion amount Iv.

[0066] In S310, a third illusion amount Iv3, which is a magnitude between the first illusion amount Iv1 and the second illusion amount Iv2, is calculated as the illusion amount Iv.

[0067] (Details of advance notification process) FIG. 6 is a flowchart showing the contents of the advance guidance process.

[0068] In S401, a travel route for the vehicle from the current position to the target point is set based on the current position of the vehicle and the target point.

[0069] In S402, it is determined whether or not the set travel route includes a section in which the passenger may be prone to motion sickness. In this embodiment, the section in which the passenger may be prone to motion sickness is a section in which a straight road is followed by a long curved road that takes a considerable amount of time to pass. If such a section exists in the travel route, the process proceeds to S403, and if not, the process ends.

[0070] In S403, a guidance is given to the passenger to encourage him / her to correct the head posture. Specifically, the guidance is given to encourage the passenger to correct the posture to prevent motion sickness because the vehicle is going to travel on a curved road. In order to avoid the inconvenience of excessive guidance, this advance guidance may be given only when the passenger is in a posture that strongly causes the passenger to feel the illusion of movement, such as when the passenger's gaze direction is downward.

[0071] In S404, it is determined whether the head posture of the occupant has been corrected. If it has been corrected, the process ends, and if it has not been corrected, the process proceeds to S405.

[0072] In S405, the vehicle operating state is forcibly changed, for example by reducing the vehicle speed VSP.

[0073] (Explanation of action and effect) The motion sickness detection device 1 according to this embodiment has the above-mentioned configuration. The effects obtained by this embodiment will be described below.

[0074] First, when a passenger experiences a state in which a lateral acceleration of a predetermined level or more is applied, and then the lateral acceleration is eliminated, the passenger is judged to be in a state in which the passenger is likely to develop motion sickness, in other words, in a state in which the passenger is likely to experience a kinesthetic illusion, which is a precursor to motion sickness. The passenger's susceptibility to kinesthetic illusions, that is, the strength of the kinesthetic illusion that the passenger actually feels, changes depending on the passenger's posture in that situation, particularly the head posture.

[0075] Therefore, based on both the head posture of the passenger when a lateral acceleration of a predetermined level or more is applied and the head posture after the lateral acceleration is released, if the passenger is in a head posture that promotes the onset of motion sickness, the system determines that the passenger is showing signs of motion sickness and provides guidance to the passenger to be careful about motion sickness.

[0076] This makes it possible to issue an alarm before the passenger begins to feel discomfort, feel unwell, or experience other symptoms of motion sickness, thereby suppressing the onset of motion sickness (motion sickness prevention), or to take measures while the symptoms are still relatively mild even if the symptoms have already begun to appear (early motion sickness countermeasures), thereby preventing the symptoms from progressing.

[0077] Secondly, it is possible to accurately detect that the passenger is in a situation where he / she is likely to develop motion sickness by transitioning from a state (first driving state) in which the vehicle speed VSP of the vehicle is equal to or greater than a predetermined vehicle speed VSP1 and the steering angle θstr is equal to or greater than a predetermined steering angle θ1 to a state (second driving state) in which the steering angle θstr is less than the predetermined steering angle θ1. Furthermore, by setting the condition for being in the above situation as being that the driving in the first driving state has continued for a predetermined period of time, it is possible to more accurately detect that the passenger is in a situation where he / she is likely to develop motion sickness.

[0078] Thirdly, the degree of progression of motion sickness can be quantified and grasped using a reference value (in this embodiment, the amount of illusion Iv), making it possible to provide passengers with appropriate guidance information regarding motion sickness according to the degree of progression.

[0079] Fourth, by making it possible to calculate the illusion amount Iv as different values ​​depending on the head rotation angles Hr, Hy, it is possible to appropriately reflect the strength of the kinesthetic illusion felt by the passenger in the illusion amount Iv, making it possible to provide the passenger with more appropriate guidance information according to their level of progress.

[0080] Specifically, when the head is rotated about the longitudinal axis Ar while driving in the first driving state (e.g., while turning), the occupant feels a stronger kinetic illusion than in other cases, that is, when the head is in an upright position while turning or when the head is rotated about an axis other than the longitudinal axis Ar. Thus, by calculating the illusion amount Iv as a relatively large value when the head roll angle Hr while turning is greater than a predetermined threshold H1 (S309, S310 shown in FIG. 5), the strength of the kinetic illusion actually felt by the occupant can be reflected in the illusion amount Iv.

[0081] Here, the kinesthetic illusion felt by the occupant is strongest when the head, which was rotated about the longitudinal axis Ar while driving in the first driving state, is returned to an upright position after transitioning to driving in the second driving state. Therefore, by detecting the head roll angle Hr' while driving straight after turning in addition to the head roll angle Hr while driving in a turn, and calculating the illusion amount Iv as the largest value when the head roll angle Hr' while driving straight is equal to or smaller than a predetermined threshold value H1 (S309 shown in FIG. 5), the strength of the kinesthetic illusion actually felt by the occupant can be more appropriately reflected in the illusion amount Iv.

[0082] On the other hand, the kinetic illusion felt by the occupant after transitioning from driving in a first driving state (e.g., turning) to driving in a second driving state (e.g., straight driving) can be mitigated or suppressed if the head is rotated about the vertical axis Ay while driving in the first driving state. Therefore, by calculating the illusion amount Iv as a relatively small value when the head yaw angle Hy during turning is greater than a predetermined threshold value H2 (S308, S310 shown in FIG. 5), the strength of the kinetic illusion actually felt by the occupant can be reflected in the illusion amount Iv.

[0083] After the vehicle transitions to driving in the second driving state, the kinesthesia felt by the occupant is weakest when the rotation axis of the head changes from the vertical axis Ay to the longitudinal axis Ar and the head is in a state of rotating about the longitudinal axis Ar while driving in the second driving state. Therefore, by calculating the illusion amount Iv as the smallest value when the head roll angle Hr' during straight driving after turning is greater than a predetermined threshold value H1 (S308 shown in FIG. 5), the strength of the kinesthesia actually felt by the occupant can be more appropriately reflected in the illusion amount Iv.

[0084] Fifth, because the direction of the gaze when a passenger is subjected to lateral acceleration affects the sensitivity to the kinesthetic illusion, by taking the direction of the gaze (gaze direction Ae) into consideration when calculating the illusion amount Iv, it is possible to calculate a more appropriate illusion amount Iv that reflects the actual strength of the kinesthetic illusion, and to provide more appropriate guidance information according to the progression of motion sickness.

[0085] Sixth, when visual information outside the vehicle can be obtained, the kinesthetic illusion becomes less noticeable or the actual kinesthetic illusion becomes weaker. Therefore, by taking into account the information obtained from the outside of the vehicle by the passenger when calculating the illusion amount Iv, it is possible to calculate a more appropriate illusion amount Iv that reflects the actual strength of the kinesthetic illusion, and to provide more appropriate guidance information according to the progression of motion sickness.

[0086] Seventh, based on the cumulative value Rm of the illusion amount Iv, it is possible to determine the degree of progression of motion sickness, including how much time there is until the onset or manifestation of subjective symptoms, and whether the motion sickness that has already developed is relatively mild or severe, making it possible to prevent or take early measures against motion sickness.

[0087] Eighth, if there is a section on the vehicle's travel route where passengers may be prone to developing motion sickness, advance notice can be provided to encourage passengers to change their head posture before they reach a situation in which they are likely to develop motion sickness; specifically, by encouraging passengers to change their head posture to one that reduces sensitivity to kinesthetic illusions, it is possible to more reliably prevent motion sickness and hinder the progression of symptoms.

[0088] Furthermore, if the occupant still fails to correct his / her head posture even after advance guidance is provided, the vehicle's operating state can be forcibly changed to reliably weaken the kinesthetic illusion felt by the occupant regardless of the occupant's head posture, thereby ensuring the prevention of motion sickness and halting the progression of symptoms.

[0089] The threshold value X1 to be compared with the reference value (illusion amount Iv) or its accumulated value Rm is not limited to one, and it is also possible to set multiple threshold values ​​X1, X2, ... of different values. Specifically, the degree of progression of motion sickness is grasped by comparison with the multiple threshold values ​​X1, X2, ..., and guidance when there is a sign of motion sickness is implemented in different manners or contents according to the accumulated value Rm. For example, when the accumulated value Rm reaches a relatively small first threshold value X1, it is notified that motion sickness may develop in the future although subjective symptoms have not yet appeared, and when the accumulated value Rm further increases and reaches a second threshold value X2 larger than the first threshold value X1, it is notified that motion sickness may already have developed and is encouraged to take a rest. [Explanation of symbols]

[0090] 1...motion sickness detection device, 101...control unit, 201...in-vehicle camera, 202...vehicle speed sensor, 203...steering angle sensor, 211...in-vehicle navigation device, 301...HMI device, P...passenger, Ar...fore-and-aft axis (roll axis), Ay...up-and-down axis (yaw axis), Ap...left-right axis (pitch axis), Hy...head yaw angle, Hr...head roll angle.

Claims

1. a driving state detection means for detecting that the vehicle is traveling in a second driving state in which the lateral acceleration applied to a passenger is less than the predetermined acceleration after traveling in a first driving state in which the lateral acceleration applied to the passenger is equal to or greater than a predetermined acceleration; a head posture detection means for detecting a head posture of the passenger; a progression degree determination means for determining a progression degree of motion sickness in the passenger based on the head posture of the passenger detected by the head posture detection means in each of the first driving state and the second driving state when the driving state detection means detects that the vehicle is driving in the second driving state after driving in the first driving state; A motion sickness detection device comprising: a signal generating means for generating a predetermined instruction signal based on the degree of progression of the motion sickness determined by the progression degree determining means.

2. 2. The motion sickness detection device according to claim 1, wherein the driving state detection means defines a state in which the steering angle of the vehicle is equal to or greater than a predetermined steering angle and the vehicle speed is equal to or greater than a predetermined vehicle speed as the first driving state, and detects that the vehicle is driving in the second driving state when the steering angle decreases to less than the predetermined steering angle after driving in the first driving state.

3. 3. The motion sickness detection device according to claim 2, wherein the driving state detection means detects that the vehicle is driving in the second driving state by a reduction in the steering angle when driving in the first driving state continues for a predetermined time or more.

4. the progression degree determination means calculates a reference value that indicates a progression degree of the motion sickness, The motion sickness detection device according to claim 1 , wherein the signal generating means generates the instruction signal when the reference value calculated by the progression degree determining means is equal to or greater than a predetermined threshold value.

5. The motion sickness detection device of claim 4, wherein the progression degree determination means calculates the reference value as a larger value when the occupant's head is rotated around a longitudinal axis while traveling in the first driving state than when the occupant's head is in an upright position or rotated around an axis other than the longitudinal axis.

6. The motion sickness detection device of claim 4, wherein the progression degree determination means calculates the reference value as a larger value than in other cases when the occupant's head is rotated around the fore-aft axis while driving in the first driving state, and when the occupant's head is in an upright position while driving in the second driving state.

7. The motion sickness detection device of claim 4, wherein the progression degree determination means calculates the reference value as a smaller value than in other cases when the head posture of the occupant changes between driving in the first driving state and driving in the second driving state, and when the occupant's head is rotated around the fore-aft axis while driving in the second driving state.

8. The vehicle further includes a gaze direction detection means for detecting a gaze direction of the passenger, The motion sickness detection device according to any one of claims 4 to 7, wherein the progression degree determination means calculates the reference value as a larger value when the gaze of the occupant detected by the gaze direction detection means while driving in the first driving state is directed downward than when the gaze is directed forward or upward.

9. The vehicle further includes a situation determination means for determining a situation in which the passenger acquires information about the outside of the vehicle. The motion sickness detection device according to claim 4 , wherein the progression degree determination means calculates the reference value as a different value depending on an outside information acquisition state of the occupant while traveling in the first driving state.

10. the progress degree determination means calculates the reference value each time the vehicle travels in the second driving state after traveling in the first driving state, and calculates a cumulative value of the reference value; The motion sickness detection device according to claim 1 , wherein the signal generating means generates the instruction signal when the cumulative value calculated by the progression degree determining means is equal to or greater than a predetermined threshold value.

11. 2. The motion sickness detection device according to claim 1, further comprising a guidance means that operates in response to the instruction signal to alert the passenger to motion sickness.

12. The motion sickness detection device according to claim 11 , wherein the signal generating means generates the instruction signal which differs depending on a progression level of the motion sickness.

13. a travel route determination means for determining whether or not the vehicle is on a route to be traveled in the second driving state after traveling in the first driving state; 2. The motion sickness detection device according to claim 1, further comprising: an advance guidance means for prompting the occupant to change his / her head posture based on the current head posture of the occupant detected by the head posture detection means when the travel route determination means determines that the occupant is on the route.

14. The motion sickness detection device of claim 13, further comprising a driving state control means for controlling the driving state of the vehicle so as to reduce the lateral acceleration applied to the occupant when traveling in the first driving state when the occupant maintains the head posture before the guidance even after guidance by the advance guidance means.

15. When the vehicle is in a first driving state in which a lateral acceleration applied to the occupant is equal to or greater than a predetermined acceleration, a first head posture is detected, the first head posture being a head posture of the occupant while traveling in the first driving state; When the vehicle is in a second driving state in which the lateral acceleration is less than the predetermined acceleration after the first driving state, a second head posture is detected, the second head posture being a head posture of the occupant while the vehicle is traveling in the second driving state; A motion sickness detection method for determining whether the passenger is experiencing signs of motion sickness based on the first head posture and the second head posture while driving in the second driving state.

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