Vehicle mental state determination device

Abstract

To appropriately detect biological information to enable appropriate drive assistance.SOLUTION: A psychological state determination device 10 for a vehicle comprises: a pair of biological information sensors (GSR measurement sensors 11) which are disposed in right and left parts so as to be separated from each other by a vertical center part of a rim 6 of a steering wheel 2 and detect biological information of a driver; and a determination device (control device 20) which determines a psychological state of the driver on the basis of the biological information. Each of the biological information sensors (11) includes two electrodes 12 provided on a surface 7 of the rim 6 so as to extend in a circumferential direction of the rim 6.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a psychological state determining device for a vehicle that determines the psychological state of a driver. [Background technology]

[0002] In recent years, efforts to provide access to sustainable transport systems that take into consideration vulnerable transport participants have been gaining momentum. To achieve this, research and development into driver assistance technologies is being focused on further improving road safety and convenience.

[0003] Patent Document 1 discloses a technology for measuring heart rate signals to continuously measure the heart rate of an operator operating a device. This technology estimates the state of a living body, such as the degree of alertness, from fluctuations in electrocardiogram signals, and presents an action according to the estimated level of alertness, enabling effective feedback of the action.

[0004] Patent Document 2 discloses an occupant condition determination system in which a detection unit for detecting the driver's pulse as biometric information is provided on the steering wheel. The detection unit includes an ultraviolet light source disposed in the internal space of the frame (rim) of the steering wheel, and electrodes disposed on the surface of the frame for capturing the occupant's pulse wave as an electrical signal. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2009-142575 A [Patent Document 2] JP 2004-16581 A Summary of the Invention [Problem to be solved by the invention]

[0006] However, in driving assistance technology, it is necessary to provide appropriate assistance to all drivers, and to achieve this, it is necessary to properly detect biological information regardless of how the steering wheel is held by various drivers. In addition, although the conventional technology measures the heart rate and estimates the wakefulness level based on the heart rate, there is room for improvement in order to provide appropriate driving assistance.

[0007] In view of the above background, the present invention aims to appropriately detect biological information and provide appropriate driving assistance, thereby contributing to the development of sustainable transportation systems. [Means for solving the problem]

[0008] In order to solve the above problems, one embodiment of the present invention is a psychological state determination device (10) for a vehicle that determines the psychological state of a driver, comprising a pair of bioinformation sensors (11) arranged on the left and right sides of a rim (6) of a steering wheel (2) so as to be separated at the top and bottom central parts, the pair of bioinformation sensors (11) detecting the driver's biological information (electrodermal activity), and a determination device (20) that determines the driver's psychological state based on the biological information, each of the bioinformation sensors including two electrodes (12) provided on a surface (7) of the rim so as to extend circumferentially around the rim.

[0009] According to this embodiment, the pair of biometric sensors are arranged on the left and right parts of the rim so as to be separated at the center between the top and bottom, and the biometric sensor includes two electrodes, so that the biometric sensor can appropriately detect biometric information no matter how the driver grips the steering wheel rim. Also, the determination device determines the driver's psychological state based on the biometric information detected by the biometric sensor, so that appropriate driving assistance based on the psychological state is possible.

[0010] In the above aspect, the two stripes of electrodes may be disposed in a region (R) on the driver's side and radially outward of the surface of the rim.

[0011] When various drivers grip the rim in various ways, in most cases the driver's hand contacts the part of the surface of the rim that is on the driver's side and on the radially outer side. According to this aspect, the biometric information sensor can appropriately detect the biometric information in most cases in which the driver grips the rim.

[0012] In the above aspect, the two stripes of electrodes may protrude from a portion (7a) between the two stripes of electrodes on the surface of the rim.

[0013] According to this embodiment, the driver's hand gripping the rim comes into contact with the two electrodes more reliably, and therefore the driver's gripping manner that can be detected by the biometric sensor is more varied.

[0014] In the above aspect, each of the biological information sensors may be a GSR measurement sensor (11) that detects the driver's electrodermal activity as the biological information.

[0015] According to this aspect, it is possible to detect the electrodermal activity of a driver gripping the rim of the steering wheel and to determine the psychological state of the driver based on the electrodermal activity.

[0016] In the above aspect, the determination device is configured to obtain the driver's heart rate interval based on the electrodermal activity, and determines the psychological state of the driver based on the electrodermal activity and the heart rate interval.

[0017] According to this aspect, the determination device can determine the psychological state not only based on the electrodermal activity but also based on the electrodermal activity and the driver's heart rate interval, thereby enabling more appropriate driving assistance according to the heart rate interval.

[0018] In the above aspect, the device may further include a steering angle sensor (15) that detects a steering angle (θ) of the steering wheel, and the determination device may be configured to set a determination period during which the psychological state should be determined and to determine the psychological state based on the biological information detected during the determination period, and may set the determination period when a predetermined steering condition related to the steering angle is satisfied.

[0019] According to this aspect, the determination device determines the psychological state based on the biological information detected during the determination period in which the psychological state should be determined, and therefore can more appropriately determine the psychological state.

[0020] In the above aspect, the steering condition may include the steering angle being smaller than a predetermined angle (θ1).

[0021] When the steering angle is greater than a predetermined angle, the vehicle may be turning, and in such a case, the driver's psychological state is likely to be tense. According to this aspect, the determination device determines the driver's psychological state based on the biological information detected when the vehicle is not turning, so that the driver's psychological state can be determined more appropriately.

[0022] In the above aspect, it is preferable that the vehicle speed acquisition device (15) for acquiring a vehicle speed (V) is further provided, and the determination device is configured to exclude, when the vehicle speed is smaller than a predetermined speed (V1), the steering condition in which the steering angle is smaller than the predetermined angle.

[0023] When the vehicle speed is lower than the predetermined speed, the vehicle may be stopped, and in such a case, the driver's psychological state is considered to be stable even if the steering wheel is displaced from the neutral position. According to this aspect, when the vehicle speed is lower than the predetermined speed, the determination device can determine the psychological state in a wider range of vehicle conditions, regardless of the magnitude of the steering angle.

[0024] In the above aspect, the determination device is configured to obtain a steering angular velocity (ω) based on the steering angle, and the steering condition preferably includes the steering angular velocity being smaller than a predetermined angular velocity (ω1).

[0025] Even if the steering angle is small, the steering angular velocity may become larger than the predetermined angular velocity when the steering is performed instantaneously. In such a situation, the biological information changes significantly, and the psychological state cannot be appropriately determined. According to this embodiment, it is possible to avoid determining the psychological state in such a case.

[0026] In the above aspect, the determination device may set the determination period when the steering condition is satisfied for a predetermined time (T1).

[0027] When the steering state is changing, the biological information is likely to change, and in such a case, the psychological state cannot be appropriately determined. According to this aspect, the psychological state is determined when the biological information is stable for a predetermined period of time, so that an appropriate determination result can be obtained. Effect of the Invention

[0028] According to the above aspect, it is possible to appropriately detect biological information, enable appropriate driving assistance, and ultimately contribute to the development of a sustainable transportation system. [Brief description of the drawings]

[0029] [Figure 1] Steering wheel front view [Diagram 2] Steering wheel cross section [Diagram 3] Block diagram of a vehicle to which a psychological state determination device is applied [Figure 4] Table showing the conditions for setting the judgment period [Diagram 5] Flow diagram of judgment period setting process [Figure 6] FIG. 1 is a diagram for explaining the operation of a psychological state assessment device. [Figure 7]Time chart for explaining the operation of the psychological state assessment device DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0030] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a psychological state assessment device 10 for a vehicle according to the present invention will be described in detail below with reference to the drawings.

[0031] Fig. 1 is a front view of a steering wheel 2 provided in a vehicle 1, and Fig. 2 is a cross-sectional view of the steering wheel 2 taken along line II-II in Fig. 1. As shown in Figs. 1 and 2, the steering wheel 2 is disposed in front of the driver's seat of the vehicle 1 as a steering member of the vehicle 1, and is mounted on the vehicle 1 in a manner such that it is attached to a steering shaft. The steering wheel 2 includes a hub 4 fixed to the steering shaft, a plurality of spokes 5 extending radially outward from the hub 4, and a rim 6 supported by the spokes 5 so as to be coaxial with the hub 4.

[0032] In the illustrated example, two spokes 5 are provided, but three or more spokes 5 may be provided. In addition, in the illustrated example, the rim 6 has a circular shape, but this is not limited thereto, and part of the arc of the rim 6 may be a straight line, and the curvature of part of the arc may be different from the curvature of the other parts. The rim 6 has a substantially circular cross section.

[0033] The rim 6 is provided with a pair of GSR measurement sensors 11, one on the left and one on the right. The GSR measurement sensors 11 are arranged on the left and right parts of the rim 6 so as to be separated at the upper and lower central parts. The GSR measurement sensors 11 are bioinformation sensors that detect the electrical skin activity (Galvanic Skin Response: GSR, also called galvanic skin response) of the hand gripping the rim 6 as bioinformation of the driver.

[0034] Specifically, each GSR measurement sensor 11 includes two electrodes 12 provided on the surface 7 of the rim 6 so as to extend in the circumferential direction of the rim 6, a DC voltage supply unit, a switch, a signal amplifier, a bandpass filter, etc. When the switch is on, the GSR measurement sensor 11 supplies voltage to the two electrodes 12 from the voltage supply unit. When the driver's hands grip the rim 6 and touch both electrodes 12, both very A minute electric current flows between the electrodes. The minute electric current changes depending on the degree of sweating in the palm of the person's hand, so by measuring the electrical signal generated by this minute electric current, it is possible to obtain the driver's electrodermal activity.

[0035] A pair of GSR measurement sensors 11 are arranged on the left and right parts of the rim 6 so as to be separated at the upper and lower central parts, and each GSR measurement sensor 11 includes two electrodes 12. Therefore, no matter how the rim 6 of the steering wheel 2 is gripped by the driver, the GSR measurement sensor 11 can appropriately detect the electrodermal activity.

[0036] This electrodermal activity represents the response of the autonomic nervous system as a parameter of the driver's sweat gland function, and can be used as a parameter representing the person's mental or psychological state. In this way, the GSR measurement sensor 11 detects the electrodermal activity, which is biological information of the driver gripping the rim 6 of the steering wheel 2, and it becomes possible to determine the driver's psychological state based on the electrodermal activity.

[0037] 2, the two-stranded electrode 12 is disposed in a region R on the driver's side and radially outward of the surface 7 of the rim 6. In other words, the two-stranded electrode 12 is disposed in the region R that the driver's hand comes into contact with when gripping the rim 6. Therefore, the GSR measurement sensor 11 can properly detect the electrodermal activity.

[0038] Each electrode 12 is generally aligned with the outer portion of the two electrodes 12 on the surface 7 of the rim 6. Therefore, a driver gripping the rim 6 does not feel any discomfort due to the unevenness of the surface 7 of the rim 6. Meanwhile, each electrode 12 protrudes from the portion 7a between the two electrodes 12 on the surface 7 of the rim 6. Therefore, the driver's hand gripping the rim 6 can more reliably contact the two electrodes 12. Therefore, the driver's gripping manner that can be detected by the GSR measurement sensor 11 is wider.

[0039] FIG. 3 is a block diagram of a vehicle 1 to which a psychological state determination device 10 is applied. The psychological state determination device 10 is a device mounted on the vehicle 1 and determines the psychological state of the driver. Although detailed illustration is omitted, the vehicle 1 is equipped with a traveling device 13 including a steering device for steering the wheels, a driving device for rotating the wheels, and a braking device for braking the rotation of the wheels. The vehicle 1 is also equipped with a steering angle sensor 14 for detecting a steering angle θ of the wheels, a vehicle speed sensor 15 for detecting the traveling speed of the vehicle 1, i.e., the vehicle speed V, an alarm device 16 for alarming the driver and passengers, and the like. Instead of providing the vehicle speed sensor 15, a vehicle speed acquisition device for acquiring the vehicle speed V based on the engine rotation speed, the motor rotation speed, and the like may be provided. The alarm device 16 may be a speaker, a display, a vibration device provided on the steering wheel 2, or the like.

[0040] The psychological state determination device 10 includes left and right GSR measurement sensors 11 provided on the steering wheel 2, and a control device 20 that serves as a determination device for determining the psychological state of the driver based on biological information measured by the GSR measurement sensors 11. The control device 20 is a device that controls the operation of devices mounted on the vehicle 1, such as the notification device 16 and the driving device 13, and the determination device is configured by at least some of its functional parts.

[0041] The control device 20 is an electronic control unit (ECU) consisting of a computer equipped with an arithmetic processing device (processor such as CPU or MPU) and a storage device (memory such as ROM or RAM). The control device 20 is configured to execute various processes required for a determination period setting process described later, a drive process for the traveling device 13, a drive process for the notification device 16, and the like. That is, the control device 20 is programmed so that the arithmetic processing device reads necessary data and application software from the storage device and executes the predetermined arithmetic processing according to the software. The control device 20 may be configured as a single piece of hardware, or may be configured as a unit consisting of multiple pieces of hardware.

[0042] The control device 20 has, as functional units, a steering angular velocity calculation unit 21, a steering condition determination unit 22, a determination period setting unit 23, a heartbeat interval acquisition unit 24, a psychological state determination unit 25, and a device control unit 26. Among these, the steering angular velocity calculation unit 21, the steering condition determination unit 22, the determination period setting unit 23, the heartbeat interval acquisition unit 24, and the psychological state determination unit 25 constitute the determination device of the psychological state determination device 10. The determination device of the psychological state determination device 10 may include the device control unit 26, or may include all of the functional units of the control device 20.

[0043] The steering angle velocity calculation unit 21 calculates the steering angle velocity ω by differentiating with respect to time the steering angle θ of the steering wheel 2 detected by the steering angle sensor 14.

[0044] The steering condition determination unit 22 determines whether or not the steering conditions required for the determination period setting process are satisfied. Fig. 4 is a table showing the setting conditions for the determination period. As shown in the figure, the steering condition, which is one of the setting conditions for the determination period, is set such that the steering angle θ is smaller than a predetermined angle θ1 and the steering angular velocity ω is smaller than a predetermined angular velocity ω1.

[0045] The predetermined angle θ1, which is a threshold value of the steering angle θ, is set to 5 deg in this embodiment, but may be 8 deg, 10 deg, or the like. The steering angle θ is given with the neutral position being 0, and one of the left and right values ​​is negative, but the steering angle θ here means absolute. The predetermined angular velocity ω1, which is a threshold value of the steering angular velocity ω, is set to 10 deg / s in this embodiment, but may be 8 deg / s, 5 deg / s, or the like. The steering angular velocity ω here also means absolute. Instead of the steering angle θ of the wheel at the steering angular velocity ω being smaller than the predetermined angle θ1, the steering angle of the steering wheel 2 being smaller than a predetermined value may be used as a steering condition.

[0046] Returning to Fig. 3, the judgment period setting unit 23 judges whether it is time to judge the psychological state based on the biological information. In other words, the judgment period setting unit 23 sets a judgment period, which is a period during which the psychological state based on the biological information should be judged. The setting of the judgment period will be described later with reference to Fig. 4.

[0047] The heartbeat interval acquiring unit 24 acquires the heartbeat interval of the driver based on the electrodermal activity measured by the left and right GSR measuring sensors 11. Specifically, when the driver holds with both hands the left and right portions of the steering wheel 2 on which the GSR measuring sensors 11 are provided, the heartbeat interval acquiring unit 24 detects the heartbeat and acquires the heartbeat interval by filtering the electrical signals of the detected electrodermal activity of both hands. Instead of the heartbeat interval acquiring unit 24 acquiring the heartbeat interval, a pulse acquiring unit that calculates the pulse, which is the reciprocal of the heartbeat interval, may be provided.

[0048] The psychological state determination unit 25 determines the psychological state based on the biological information detected during the determination period set by the determination period setting unit 23. The psychological state determination unit 25 determines the psychological state using at least electrodermal activity as the biological information. When the driver is holding the steering wheel 2 with both hands, the psychological state determination unit 25 of this embodiment determines the psychological state based on the electrodermal activity and the heartbeat interval.

[0049] When judging the psychological state, the psychological state judgment unit 25 may use the detection value of one of the GSR measurement sensors 11. The GSR measurement sensor 11 used to judge the psychological state may be, for example, the one that detected the electrodermal activity when the hand was gripped with one hand before the hand gripped with both hands. Alternatively, the psychological state judgment unit 25 may determine the GSR measurement sensor 11 to be adopted based on the data state for several seconds before the start of the judgment period. By the state judgment unit using the detection value of one of the GSR measurement sensors 11, the fluctuation of the electrodermal activity is suppressed from becoming large.

[0050] The device control unit 26 controls the operation of the traveling device 13 and the notification device 16. For example, when the driver's psychological state is in an abnormal state (anxious state, tense state, panic state, etc.) different from a normal psychological state, the device control unit 26 may drive the notification device 16 to ask the driver, "Are you in trouble?" Furthermore, when the driver's psychological state is in an abnormal state, the device control unit 26 may drive at least one of the steering device, the drive device, and the braking device to assist the driver in driving.

[0051] In this way, the psychological state determination unit 25 determines the psychological state of the driver based on the biological information detected by the GSR measurement sensor 11, which is a biological information sensor, so that appropriate driving assistance based on the psychological state becomes possible.

[0052] The control device 20, which serves as a determination device, is configured to obtain the heart rate interval of the driver based on the electrodermal activity, and determines the psychological state of the driver based on the electrodermal activity and the heart rate interval. This enables more appropriate driving assistance using the heart rate interval.

[0053] As shown in FIG. 4, the judgment period indicating that a psychological state should be judged based on biological information (that it is the right time) is set when three conditions are met, among the eight conditions shown in each row of the table shown in FIG. 4, which are marked "Yes" in the judgment period column. One of the conditions is when the vehicle speed V is greater than 1 km / h (predetermined speed V1), the steering angle θ is less than 5 deg (predetermined angle θ1), and the steering angular velocity ω is less than 10 deg / s (predetermined angular velocity ω1), for five seconds (predetermined time T1). In this case, it is considered that the vehicle 1 is traveling straight ahead. The second and third conditions are when the vehicle speed V is less than 1 km / h (predetermined speed V1), and the steering angular velocity ω is less than 10 deg / s (predetermined angular velocity ω1), for five seconds (predetermined time T1). One of these is set assuming a state in which the vehicle 1 is temporarily stopped before turning at an intersection, with the steering angle θ being greater than 5 degrees (predetermined angle θ1), and the other is set assuming a state in which the vehicle 1 is parked or stopped, with the steering angle θ being less than 5 degrees (predetermined angle θ1).

[0054] When the vehicle speed V is greater than 1 km / h and the steering angle θ is greater than 5 deg, if the steering angular velocity ω is greater than 10 deg / s, the vehicle 1 is in a state where the driver is intentionally steering the vehicle 1, and the state is considered to be unsuitable for judgment, and therefore, the period is not set as a judgment period. On the other hand, if the steering angular velocity ω is less than 10 deg / s, the vehicle 1 is in a steady turning state, and the state is considered to be unsuitable for judgment, and therefore, the period is not set as a judgment period. Also, when the vehicle speed V is greater than 1 km / h, even if the steering angle θ is greater than 5 deg, if the steering angular velocity ω is greater than 10 deg / s, the vehicle 1 is in a state where the driver is momentarily steering the vehicle 1, and the state is considered to be unsuitable for judgment, and therefore, the period is not set as a judgment period.

[0055] When the vehicle speed V is less than 1 km / h and the steering angular velocity ω is greater than 10 deg / s, if the steering angle θ is greater than 5 deg, the vehicle 1 is considered to be in a state where the driver is steering the vehicle stationary. On the other hand, if the steering angle θ is greater than 5 deg, the vehicle 1 is considered to be in a state where the driver is steering the vehicle momentarily. These states are considered to be unsuitable for judgment, and therefore are not set in the judgment period.

[0056] In order to set the determination period according to such conditions, the control device 20 repeatedly executes the determination period setting process shown in Fig. 5 at predetermined time intervals. A specific procedure will be described below with reference to Fig. 5.

[0057] The control device 20 first determines whether the steering angle θ is smaller than a predetermined angle θ1 (step ST1). If the steering angle θ is equal to or larger than the predetermined angle θ1 (5 deg) (ST1: No), the control device 20 determines whether the vehicle speed V is smaller than a predetermined speed V1 (1 km / h) (step ST2). If the steering angle θ is smaller than the predetermined angle θ1 (ST1: Yes) and if the vehicle speed V is smaller than the predetermined speed V1 (ST2: Yes), the control device 20 determines whether the steering angular velocity ω is smaller than a predetermined angular velocity ω1 (10 deg / s) (step ST3).

[0058] If the steering angular velocity ω is smaller than the predetermined angular velocity ω1 (ST3: Yes), the control device 20 judges whether or not the steering condition flag is 0 (step ST4). The steering condition flag is a flag that should be set to 1 if the above steering conditions (the steering angle θ is smaller than the predetermined angle θ1 (ST1: Yes) and the steering angular velocity ω is smaller than the predetermined angular velocity ω1 (ST3: Yes)) are satisfied, and set to 0 if they are not satisfied. If the steering condition flag is 0 (ST4: Yes), the control device 20 sets the steering condition flag to 1 (step ST5), starts a timer (step ST6), ends this routine, and repeats the processing from the start.

[0059] If the steering condition flag is 1 in step ST4 (No), the control device 20 checks the timer and determines whether or not a predetermined time T1 has elapsed (step ST7). If the predetermined time T1 has not elapsed (ST7: No), the control device 20 ends this routine and repeats the process from the start. On the other hand, if the predetermined time T1 has elapsed (ST7: Yes), the control device 20 sets a judgment period, that is, starts judging the psychological state based on the biological information. The judgment of the psychological state is performed by the control device 20 based on the biological information detected during the judgment period.

[0060] If the steering angle θ is equal to or greater than a predetermined angle θ1 (ST1: No) and the vehicle speed V is equal to or greater than a predetermined speed V1 (ST2: No), the control device 20 judges whether the steering condition flag is 1 or not (step ST9). If the steering angular velocity ω is equal to or greater than a predetermined angular velocity ω1 (No) in step ST3, the control device 20 also executes the process of step ST9. If the steering condition flag is 1 (ST9: Yes), the control device 20 sets the steering condition flag to 0 (step ST10), resets the timer (step ST11), and cancels the judgment period, that is, ends the judgment of the psychological state based on the biological information. Then, the control device 20 ends this routine and repeats the process from the start. Also, if the steering condition flag is 0 in step ST9 (ST9: No), the control device 20 does not perform any process, ends this routine, and repeats the process from the start.

[0061] By the control device 20 executing the judgment period setting process in this manner, a judgment period is set when the three conditions indicated as Yes in the table of FIG. 4 exist, and a judgment period is not set when the five conditions indicated as No exist.

[0062] Next, the operation of the psychological state assessment device 10 will be described with reference to Fig. 6 and Fig. 7. Here, the operation when the vehicle 1 goes from going straight to turning right and then turning left will be described as shown in Fig. 6. This period can be divided into a first period P1 of going straight, a second period P2 of turning right (right turning state), a third period P3 of going straight, a fourth period P4 of turning left (left turning state), and a fifth period P5 of going straight, depending on the state of the vehicle 1.

[0063] FIG. 7 is a time chart showing the vehicle information and the driver's biological information during this period. The first period P1 is set as a judgment period because the vehicle speed V is high while the steering angle θ and the steering angular velocity ω are both small. The second period P2 is set as a non-judgment period because the steering angle θ and the steering angular velocity ω are both large. The third period P3 is set as a judgment period because the vehicle speed V is high while the steering angle θ and the steering angular velocity ω are both small. The fourth period P4 is set as a non-judgment period because the steering angle θ and the steering angular velocity ω are both large. The fifth period P5 is set as a judgment period because the vehicle speed V is high while the steering angle θ and the steering angular velocity ω are both small.

[0064] In this way, when the predetermined steering condition related to the steering angle θ is satisfied (ST1: Yes, ST2: Yes), the control device 20 sets the judgment period in step ST8 (ST8). Then, the control device 20 judges the psychological state based on the biological information detected during the judgment period in which the psychological state should be judged, so that the control device 20 can judge the psychological state more appropriately.

[0065] When the steering angle θ is greater than the predetermined angle θ1, the vehicle 1 may be turning, and in such a case, the driver's psychological state is likely to be tense. Therefore, the control device 20 confirms in step ST1 that the steering angle θ is smaller than the predetermined angle θ1 as a steering condition for setting the judgment period in step ST8. This allows the control device 20 to judge the driver's psychological state based on the biological information detected when the vehicle 1 is not turning, so that the driver's psychological state can be judged more appropriately.

[0066] When the vehicle speed V is smaller than the predetermined speed V1, the vehicle 1 may be stopped, and in such a case, the driver's psychological state is considered to be stable even if the steering wheel 2 is displaced from the neutral position. Therefore, when the vehicle speed V is smaller than the predetermined speed V1 (ST2: Yes), the control device 20 advances the process to step ST3, that is, removes the steering angle θ being smaller than the predetermined angle θ1 from the steering conditions. As a result, when the vehicle speed V is smaller than the predetermined speed V1, the control device 20 can determine the psychological state in a wider range of vehicle 1 conditions, regardless of the magnitude of the steering angle θ.

[0067] Even if the steering angle θ is a small value, the steering angular velocity ω may become larger than the predetermined angular velocity ω1 when steering is performed instantaneously. In such a situation, the biological information changes significantly, and the psychological state cannot be appropriately determined. Therefore, the control device 20 includes in the steering conditions that the steering angular velocity ω in step ST3 is smaller than the predetermined angular velocity ω1. This makes it possible to avoid determining the psychological state in such a case.

[0068] When the steering state is changing, the biological information is likely to change, and in such a case, the psychological state cannot be judged appropriately. Therefore, when the steering condition is satisfied for a predetermined time T1 (ST7: Yes), the control device 20 sets a judgment period in step ST9. This allows the psychological state to be judged when the biological information is stable for the predetermined time T1, and an appropriate judgment result can be obtained.

[0069] Although the description of the specific embodiment is finished above, the present invention is not limited to the above embodiment and modified examples, and can be widely modified. For example, instead of the GSR measurement sensor 11 being provided as a bioinformation sensor, other bioinformation sensors such as an electrocardiogram measurement sensor, a pulse measurement sensor, and a skin temperature measurement sensor may be provided. In addition, the specific configuration and arrangement of each member and part, the number, material, and the value of the judgment threshold value can be appropriately changed within the scope of the gist of the present invention. Furthermore, the processing procedure shown in the above embodiment is an example, and is not limited to this. Furthermore, all of the components shown in the above embodiment are not essential, and can be selected as appropriate. [Explanation of symbols]

[0070] 1: Vehicle 2: Steering wheel 4: Hub 5: Spokes 6: Rim 7: Surface 7a: Intermediate part 10: Psychological state assessment device 11: GSR measurement sensor (biometric information sensor) 12: Electrode 13: Running gear 14: Steering angle sensor 15: Vehicle speed sensor (an example of a vehicle speed acquisition device) 16: Notification device 20: Control device (judgment device) 21: Steering angular velocity calculation section 22: Steering condition determination unit 23: Judgment period setting section 24: Heart rate interval acquisition unit 25: Psychological state determination section 26: Device control section R: area T1: Predetermined time V:Vehicle speed V1:Predetermined speed θ: Turning angle θ1: Predetermined angle ω: Turning angular speed ω1: Predetermined angular velocity

Claims

1. A psychological state determination device for a vehicle that determines a psychological state of a driver, a pair of biometric sensors arranged on the left and right portions of the steering wheel rim so as to be separated at the upper and lower central portions of the rim, the biometric sensors detecting biometric information of the driver; a determination device for determining the psychological state of the driver based on the biological information; a steering angle sensor for detecting a steering angle of the steering wheel, Each of the biometric sensors includes two stripes of electrodes provided on a surface of the rim so as to extend in a circumferential direction of the rim, The psychological state determination device is configured to set a determination period during which the psychological state should be determined, and determine the psychological state based on the biological information detected during the determination period, and sets the determination period when a predetermined steering condition related to the steering angle is satisfied.

2. 2. The psychological state determination device according to claim 1, wherein the two electrodes are arranged in a region on the surface of the rim that is on the driver's side and radially outward.

3. 2. The psychological state assessment device according to claim 1, wherein the two electrodes protrude from a portion of the surface of the rim between the two electrodes.

4. The psychological state determination device according to claim 1 , wherein each of the biological information sensors is a GSR measurement sensor that detects an electrical skin activity of the driver as the biological information.

5. The psychological state determination device according to claim 4 , wherein the determination device is configured to obtain the driver's heart rate interval based on the electrodermal activity, and determines the driver's psychological state based on the electrodermal activity and the heart rate interval.

6. 6. The psychological state determination device according to claim 1, wherein the steering condition includes that the steering angle is smaller than a predetermined angle.

7. A vehicle speed acquisition device for acquiring a vehicle speed is further provided.

7. The psychological state determination device according to claim 6, wherein the determination device is configured to exclude from the steering conditions a steering angle smaller than the predetermined angle when the vehicle speed is smaller than a predetermined speed.

8. The determination device is configured to obtain a steering angular velocity based on the steering angle, 6. The psychological state determination device according to claim 1, wherein the steering condition includes that the steering angular velocity is smaller than a predetermined angular velocity.

9. 6. The psychological state determination device according to claim 1, wherein the determination device sets the determination period when the steering condition is satisfied for a predetermined time.

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