Driver Monitoring Device

Abstract

To effectively determine whether a driver is in a particular state according to use of driving assistance.SOLUTION: A driver monitoring device, which is applied to a vehicle equipped with a driver assistance device capable of executing a predetermined driving assistance for assisting driving of a driver, includes: a driver status acquiring unit for acquiring a driver status; and a driver status determination unit that determines that the driver is in a particular state when the driver status acquired by the driver status acquisition unit satisfies a predetermined condition. The driver state determination unit relaxes the predetermined condition when the driver assistance device is performing driver assistance, compared to when the driver assistance device is not performing driver assistance.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present disclosure relates to a driver monitoring device. Place Regarding. [Background technology]

[0002] Patent Document 1 discloses a device that detects the driver's gaze behavior using a driver monitor unit, determines the driver's state based on the detected gaze behavior, and performs information display control and vehicle control at appropriate times based on the determination results. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2002-025000 Summary of the Invention

[0004] When a driver uses driving assistance such as adaptive cruise control (ACC) or lane trace assist (LTA), the driver's attention tends to decrease. In such cases, it is preferable from a safety standpoint to display information to the driver or to start vehicle control earlier. In order to more effectively advance the timing to display information to the driver or to start vehicle control, it is desirable to detect early whether the driver's state is in a predetermined specific state. However, if the driver's state is always determined based on the same conditions regardless of whether the driver is using driving assistance, there is a problem in that it is not possible to advance the timing to detect that the driver is in a specific state when the driver's attention is actually decreased due to the use of driving assistance.

[0005] One object of the present disclosure is to provide a technology that can effectively determine whether a driver is in a specific state depending on the usage status of driving assistance.

[0006] The driver monitoring device of the present disclosure is a driver monitoring device that is applied to a vehicle equipped with a driving assistance device that can execute predetermined driving assistance to assist the driver in driving, and includes a driver state acquisition unit that acquires the state of the driver, and a driver state determination unit that determines that the driver is in a specific state when the driver state acquired by the driver state acquisition unit satisfies predetermined conditions, and when the driving assistance device is executing the driving assistance, the driver state determination unit relaxes the predetermined conditions compared to when the driving assistance is not being executed.

[0007] According to the above configuration, when the driving assistance device is performing driving assistance, the driver monitoring device relaxes the conditions for determining whether the driver is in a specific state. This makes it possible to quickly detect that the driver is in a specific state when the driver's attention is reduced due to the use of driving assistance. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a schematic diagram showing a hardware configuration of a vehicle according to an embodiment of the present invention. [Figure 2] FIG. 2 is a schematic diagram showing a software configuration of the control device according to the present embodiment. [Figure 3] 10 is a flowchart illustrating a routine for a determination condition relaxation process. [Figure 4] 10 is a flowchart illustrating a driver abnormality determination process routine. [Figure 5] 4 is a flowchart illustrating a routine for processing collision avoidance control. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, a driver monitoring device and a driver monitoring method according to this embodiment will be described with reference to the drawings.

[0010] [Hardware configuration] 1 is a schematic diagram showing the hardware configuration of a vehicle SV to which a driver monitoring device according to this embodiment is applied. Hereinafter, the vehicle SV may also be referred to as the host vehicle when it is necessary to distinguish it from other vehicles.

[0011] The vehicle SV has an ECU (Electronic Control Unit) 10. The ECU 10 includes a CPU (Central Processing Unit) 11, a ROM (Read Only Memory) 12, a RAM (Random Access Memory) 13, and an interface device 14. The CPU 11 is a processor that executes various programs stored in the ROM 12. The ROM 12 is a non-volatile memory that stores data and the like required for the CPU 11 to execute the various programs. The RAM 13 is a volatile memory that provides a working area into which the various programs are expanded when the CPU 11 executes them. The interface device 14 is a communication device for communicating with external devices.

[0012] The ECU 10 is a central device that performs driving assistance control such as ACC, LTA, and collision avoidance control (Pre-Crash Safety Control: hereinafter referred to as PCS control). Driving assistance control is a concept that includes automatic driving control. The ECU 10 is communicably connected to a drive unit 20, a steering unit 21, a braking unit 22, an internal sensor unit 30, an external sensor unit 40, a driver monitor unit 50, an ACC operation unit 60, an LTA start switch 65, a speaker 95, and the like.

[0013] The drive device 20 generates a drive force to be transmitted to the drive wheels of the vehicle SV. Examples of the drive device 20 include an electric motor and an engine. In this embodiment, the vehicle SV may be a hybrid vehicle (HEV), a plug-in hybrid vehicle (PHEV), a fuel cell vehicle (FCEV), an electric vehicle (BEV), or an engine vehicle. The steering device 21 applies a steering force to the wheels of the vehicle SV. The braking device 22 applies a braking force to the wheels of the vehicle SV.

[0014] The internal sensor device 30 is a group of sensors that detect the state of the vehicle SV. Specifically, the internal sensor device 30 includes a vehicle speed sensor 31, an accelerator sensor 32, a brake sensor 33, a steering angle sensor 34, a yaw rate sensor 35, an acceleration sensor 36, a turn signal switch 37, and the like.

[0015] The vehicle speed sensor 31 detects the traveling speed (vehicle speed V) of the vehicle SV. The accelerator sensor 32 detects the amount of operation of an accelerator pedal (not shown) by the driver. The brake sensor 33 detects the amount of operation of a brake pedal (not shown) by the driver. The steering angle sensor 34 detects the rotation angle of a steering wheel or steering shaft (not shown) of the vehicle SV, i.e., the steering angle. The yaw rate sensor 35 detects the yaw rate of the vehicle SV. The acceleration sensor 36 detects the acceleration of the vehicle SV. The turn signal switch 37 detects the operation of a turn signal lever (not shown) by the driver. The internal sensor device 30 transmits the state of the vehicle SV detected by each sensor 31 to 37 to the ECU 10 at a predetermined interval.

[0016] The external sensor device 40 is a type of sensor that recognizes target information related to targets around the vehicle SV. Specifically, the external sensor device 40 includes a radar sensor 41, a camera sensor 42, etc. Examples of target information include nearby vehicles, pedestrians, traffic lights, white lines on the road, signs, fallen objects, etc.

[0017] The radar sensor 41 is provided, for example, at the front of the vehicle SV and detects targets present in the area ahead of the vehicle SV. The radar sensor 41 includes a millimeter-wave radar and / or a lidar. The millimeter-wave radar emits millimeter-wave radio waves (millimeter waves) and receives millimeter waves (reflected waves) reflected by targets present within the emission range. The millimeter-wave radar acquires the relative distance and relative speed between the vehicle SV and the target based on the phase difference between the transmitted millimeter waves and the received reflected waves, the attenuation level of the reflected waves, and the time from transmitting the millimeter waves to receiving the reflected waves. The lidar sequentially scans a pulsed laser beam with a wavelength shorter than that of millimeter waves in multiple directions and receives the reflected light reflected by the target to acquire the shape of the target detected ahead of the vehicle SV, the relative distance and relative speed between the vehicle SV and the target, etc.

[0018] The camera sensor 42 is, for example, a stereo camera or a monocular camera, and a digital camera having an imaging element such as a CMOS or CCD can be used. The camera sensor 42 is disposed, for example, above the front windshield glass of the vehicle SV. The camera sensor 42 captures an image of the area ahead of the vehicle SV and processes the captured image data to acquire target information ahead of the vehicle SV. The target information is information that indicates the type of target detected ahead of the vehicle SV, the relative distance between the vehicle SV and the target, the relative speed between the vehicle SV and the target, etc. The type of target may be recognized, for example, by machine learning such as pattern matching.

[0019] The external sensor device 40 repeatedly transmits the acquired target object information to the ECU 10 every time a predetermined time period has elapsed. The ECU 10 determines the relative relationship between the vehicle SV and the target by combining the relative relationship between the vehicle SV and the target obtained by the radar sensor 41 and the relative relationship between the vehicle SV and the target obtained by the camera sensor 42. Note that the external sensor device 40 does not necessarily have to include both the radar sensor 41 and the camera sensor 42, and may include, for example, only the radar sensor 41 or only the camera sensor 42.

[0020] The driver monitoring device 50 is a device that acquires the state of the driver of the vehicle SV, and includes a driver camera 51, a steering touch sensor (hereinafter referred to as touch sensor) 52, etc. The driver camera 51 mainly captures an image of the driver's face, and detects the driver's facial orientation, line of sight, eye open state, etc. from the captured facial image. The touch sensor 52 detects whether the driver is gripping the steering wheel. The driver monitoring device 50 transmits the driver's state (hereinafter referred to as driver state information) acquired based on the detection results of the driver camera 51 and touch sensor 52 to the ECU 10 at a predetermined interval. Note that the driver monitoring device 50 does not need to include both the driver camera 51 and the touch sensor 52, and may be configured to include only the driver camera 51. The driver monitoring device 50 may also include other sensors that can acquire the driver's state, such as a physiological measurement device that measures the driver's heart rate, pulse rate, etc., and a seating sensor that detects the driver's seating state.

[0021] The ACC operation unit 60 is provided near the driver's seat (for example, on the steering wheel, steering column, etc.) and is a group of switches operated by the driver. The ACC operation unit 60 includes, for example, an ACC start switch 61 for selecting whether to start or end the ACC, a setting switch 62 for setting the target vehicle speed and target inter-vehicle distance (target inter-vehicle time) for the ACC, a cancel switch 63 for temporarily canceling the ACC that is running, and a resume switch 64 for restarting the ACC.

[0022] The LTA activation switch 65 is provided near the driver's seat (for example, on the steering wheel, etc.) The LTA activation switch 65 is an ON / OFF switch that allows the driver to select whether to activate or terminate the LTA.

[0023] The speaker 95 is, for example, a speaker for an audio system or a speaker for a navigation system, and outputs warning sounds and the like in response to commands from the ECU 10 .

[0024] [Software configuration] FIG. 2 is a schematic diagram showing the software configuration of the ECU 10 according to this embodiment. As shown in FIG. 2, the ECU 10 includes, as functional elements, an ACC control unit 100, an LTA control unit 110, a distraction state determination unit 120, a driver state determination unit 130, and a PCS control unit 140. These functional elements 100-140 are realized by the CPU 11 of the ECU 10 reading a program stored in the ROM 12 into the RAM 13 and executing it. Note that, in this embodiment, the functional elements 100-140 are described as being included in the ECU 10, which is an integrated piece of hardware; however, some of these functional elements may be provided in another ECU separate from the ECU 10. Furthermore, all or some of the functional elements 100-140 of the ECU 10 may be provided in an information processing device in a facility (e.g., a management center) capable of communicating with the vehicle SV.

[0025] The ACC control unit 100 executes ACC based on the target vehicle speed and the target inter-vehicle distance (or the target inter-vehicle time). ACC itself is well known, so it will be briefly explained below. ACC includes two types of control: constant speed cruise control and follow-up cruise control. Constant speed cruise control is a control that causes the vehicle SV to travel at a constant speed according to a target vehicle speed without the driver needing to operate the accelerator or brake. Follow-up cruise control is a control that causes the host vehicle SV to follow the preceding vehicle while maintaining the inter-vehicle distance between the preceding vehicle and the host vehicle SV at a target inter-vehicle distance without the driver needing to operate the accelerator or brake. The preceding vehicle is a vehicle that is traveling in the area ahead of the host vehicle SV and immediately before the host vehicle SV.

[0026] When the ACC start switch 61 is turned ON, the ACC control unit 100 determines whether or not there is a preceding vehicle to be followed, based on the target object information transmitted from the external sensor device 40. If the ACC control unit 100 determines that there is no preceding vehicle, it executes constant speed cruise control. In this case, the ACC control unit 100 controls the drive of the drive unit 20 so that the vehicle speed V matches the target vehicle speed, and also controls the operation of the braking device 22 as needed. On the other hand, if the ACC control unit 100 determines that there is a preceding vehicle, it executes follow-up cruise control. In this case, the ACC control unit 100 controls the drive of the drive unit 20 so that the inter-vehicle distance between the host vehicle SV and the preceding vehicle matches the target inter-vehicle distance, and also controls the operation of the braking device 22 as needed.

[0027] The LTA control unit 110 executes the LTA, which automatically changes the steering angle (the steering angle of the steered wheels) so that the position of the host vehicle SV is maintained near a target driving line within the driving lane. Since the LTA itself is well known, it will be briefly described below. When the LTA activation switch 65 is turned on, the LTA control unit 110 sets a target driving line for the host vehicle SV based on either or both of the white lines recognized by the external sensor device 40 and the driving trajectory (hereinafter referred to as the preceding vehicle trajectory) of a vehicle to be followed by ACC (i.e., a preceding vehicle). The preceding vehicle trajectory may be acquired based on target object information transmitted from the external sensor device 40. The LTA control unit 110 changes the steering angle of the host vehicle SV by controlling the operation of the steering device 21 so that the lateral position of the host vehicle SV (i.e., the position of the host vehicle SV in the vehicle width direction relative to the road) is maintained near the target driving line within the driving lane.

[0028] The LTA control unit 110 changes the method for setting the target driving line depending on the recognition status of the white lines and the presence or absence of a vehicle to be followed. For example, if the left and right white lines can be recognized far away, the LTA control unit 110 sets the target driving line based on the center line of the driving lane. In other words, the LTA control unit 110 sets the target driving line based only on the white lines. On the other hand, if a vehicle to be followed is present and the left and right white lines cannot be recognized, or if only the left and right white lines can be recognized in the vicinity, the LTA control unit 110 sets the target driving line based on the preceding vehicle's trajectory alone or both the preceding vehicle's trajectory and the center line of the driving lane. If there is no vehicle to be followed and the left and right white lines cannot be recognized far away, the LTA control unit 110 cancels the execution of LTA.

[0029] The distraction state determination unit 120 determines whether the driver is in a distracted state, i.e., not paying attention to the surroundings, when the driver is using the ACC and / or LTA. If the driver continues to use the ACC or LTA for a predetermined time or longer, the driving operation becomes monotonous, and the driver is likely to become distracted. The distraction state determination unit 120 determines that the driver is in a distracted state when the touch sensor 52 does not detect the driver's continuous grip on the steering wheel, when the steering angle sensor 34 does not detect the driver's steering operation by a predetermined amount or more, or when the other driving operation by the driver is not detected, within a predetermined time after at least one of the ACC activation switch 61 and the LTA activation switch 65 is turned ON. Examples of other driving operations include depressing the accelerator pedal, depressing the brake pedal, temporarily canceling the ACC by turning ON the cancel switch 63, resuming the ACC by turning ON the resume switch 64, operating the turn signal lever, etc. When the distracted state determination unit 120 determines that the driver is in a distracted state, it transmits the determination result to the driver state determination unit 130 .

[0030] The driver state determination unit 130 determines, based on the driver state information transmitted from the driver monitoring device 50, whether the driver is in an abnormal state (specific state) in which it is difficult for the driver to continue operating the vehicle SV due to continuous inattention, drowsiness, seizures, etc. The driver state determination unit 130 acquires the driver's line of sight, eye openness, grip of the steering wheel, etc., based on the driver state information transmitted from the driver monitoring device 50. The driver state determination unit 130 determines that the driver is in an abnormal state when at least one of a first state in which the driver's line of sight is out of a predetermined range including the front of the vehicle SV, a second state in which the driver's eyes are closed, or a third state in which the driver is not gripping the steering wheel continues for a predetermined first threshold time T1 or more.

[0031] Here, when a driver uses a driving assistance system such as ACC or LTA, the driver's attention is likely to decrease. Therefore, it is desirable to shorten the first threshold time T1, i.e., relax the judgment conditions, to detect driver abnormalities early. However, if the judgment conditions are always relaxed just because the driver is using ACC or LTA, there is a possibility of frequent erroneous judgments. Therefore, the driver state judgment unit 130 relaxes the judgment conditions when the distraction state judgment unit 120 judges the driver to be in a distracted state while ACC and / or LTA are operating. Specifically, the driver state judgment unit 130 performs driver abnormality judgment based on a first relaxed threshold time T1′ (=T1−Td1), which is obtained by subtracting a predetermined amount Td1 from the first threshold time T1. This makes it possible to detect driver abnormalities early when the driver uses ACC or LTA and is in a distracted state. The predetermined amount Td1 used to shorten the first threshold time T1 may be a fixed value or a variable value. When the predetermined amount Td1 is a variable value, the higher the vehicle speed V, the larger the predetermined amount Td1 may be.

[0032] The PCS control unit 140 executes PCS control to avoid a collision between the host vehicle SV and a forward target or to mitigate damage from the collision. Specifically, the PCS control unit 140 acquires coordinate information of an object present ahead of the host vehicle SV based on target information transmitted from the external sensor device 40. The PCS control unit 140 also calculates the turning radius of the host vehicle SV based on the detection results of the vehicle speed sensor 31, the steering angle sensor 34, and the yaw rate sensor 35, and calculates the trajectory of the host vehicle SV based on this turning radius. The PCS control unit 140 determines whether a moving object or a stationary object ahead of the host vehicle SV is an obstacle that may collide with the host vehicle SV. If the object is a moving object, the PCS control unit 140 calculates the trajectory of the moving object based on the coordinate information of the moving object, and determines that the moving object is an obstacle if the trajectory of the moving object intersects with the trajectory of the host vehicle SV. Furthermore, if the object is a stationary object, the PCS control unit 140 determines that the stationary object is an obstacle if the trajectory of the vehicle SV intersects with the current position of the stationary object.

[0033] When the PCS control unit 140 determines that an object is an obstacle, it calculates a time to collision (TTC) until the host vehicle SV collides with the obstacle based on the distance L from the host vehicle SV to the obstacle and the relative speed Vr of the host vehicle SV with respect to the obstacle. The TTC is an index value that indicates the possibility that the host vehicle SV will collide with the obstacle. The TTC can be calculated by dividing the distance L from the host vehicle SV to the obstacle by the relative speed Vr (TTC=L / vr).

[0034] If the state in which the TTC is equal to or less than the predetermined collision determination threshold Tv continues for a predetermined second threshold time T2 or more, the PCS control unit 140 determines that there is a high possibility that the host vehicle SV will collide with an obstacle. When the PCS control unit 140 determines that there is a high possibility of a collision, it issues an alarm via the speaker 95 and starts deceleration control. The deceleration control is a control that decelerates the vehicle SV by controlling the operation of the braking device 22 so that the deceleration of the vehicle SV matches a predetermined target deceleration. In this way, by setting the condition for executing the deceleration control or the alarm as the state in which the TTC is equal to or less than the collision determination threshold Tv continuing for a predetermined second threshold time T2 or more, unnecessary activation of the deceleration control or the alarm can be effectively suppressed.

[0035] Here, when the driver is in an abnormal state, it is desirable to ease the conditions for executing deceleration control or issuing a warning, thereby accelerating the deceleration control or issuing a warning. When the driver state determination unit 130 determines that the driver is in an abnormal state, the PCS control unit 140 determines whether to execute deceleration control or issuing a warning based on the second relaxed threshold time T2' (=T2-Td2), which is obtained by subtracting the predetermined amount Td2 from the second threshold time T2. As a result, when an abnormality in the driver is detected, deceleration control or issuing a warning is accelerated, thereby improving safety. The predetermined amount Td2 that shortens the second threshold time T2 may be a fixed value or a variable value. If the predetermined amount Td2 is a variable value, for example, the predetermined amount Td2 may be increased as the vehicle speed V increases.

[0036] 3 is a flowchart illustrating a routine for processing to relax the determination conditions by the CPU 11 of the ECU 10. This routine is started, for example, when the vehicle SV starts to move.

[0037] In step S100, the ECU 10 determines whether the driver is using the driving assistance, that is, whether at least one of the ACC activation switch 61 and the LTA activation switch 65 is turned ON. If the driver is using the driving assistance (Yes), the ECU 10 proceeds to the processing of step S110. On the other hand, if the driver is not using the driving assistance (No), the ECU 10 proceeds to the processing of step S130.

[0038] In step S110, the ECU 10 determines whether the driver is in a distracted state. Specifically, if the touch sensor 52 does not detect the driver continuously gripping the steering wheel, or if the steering angle sensor 34 does not detect a steering operation by the driver of a predetermined amount or more, or if the steering angle sensor 34 does not detect any other driving operation by the driver, within a predetermined time period after at least one of the ACC activation switch 61 and the LTA activation switch 65 is turned ON, the ECU 10 determines that the driver is in a distracted state. If the driver is in a distracted state (Yes), the ECU 10 proceeds to the processing of step S120. On the other hand, if the driver is not in a distracted state (No), the ECU 10 proceeds to the processing of step S130.

[0039] In step S120, the ECU 10 sets the determination condition mitigation flag F1, which subtracts a predetermined amount Td1 from the first threshold time T1, to ON (F1=1), and returns from this routine. On the other hand, if the process proceeds from step S100 or S110 to step S130, the ECU 10 sets the determination condition mitigation flag F1 to OFF (F1=0), and returns from this routine.

[0040] 4 is a flowchart illustrating a driver abnormality determination routine executed by the CPU 11 of the ECU 10. This routine is started, for example, when the vehicle SV starts to move, and is executed in parallel with the determination condition relaxation routine shown in FIG.

[0041] In step S200, the ECU 10 acquires driver state information from the driver monitoring device 50. Next, in step S210, the ECU 10 determines whether the determination condition relaxation flag F1 has been set to on (F1=1) by the above-described determination condition relaxation process. If the determination condition relaxation flag F1 is set to on (Yes), the ECU 10 proceeds to the process of step S220.

[0042] In step S220, the ECU 10 determines whether the driver is in an abnormal state based on a first mitigation threshold time T1' (=T1-Td1) obtained by subtracting a predetermined amount Td1 from the first threshold time T1. Specifically, the ECU 10 determines whether at least one of the following states continues for the first mitigation threshold time T1' or longer: a first state in which the driver's line of sight is outside a predetermined range including the front of the vehicle SV; a second state in which the driver's eyes are closed; or a third state in which the driver is not gripping the steering wheel. If the determination result is negative (No), the ECU 10 returns from this routine. On the other hand, if the determination result is positive (Yes), the ECU 10 proceeds to step S240, determines that the driver is in an abnormal state, and returns from this routine.

[0043] If the determination in step S210 is negative (No), i.e., if the determination condition mitigation flag F1 is off (F1=0), the ECU 10 proceeds to the processing of step S230. In step S230, the ECU 10 determines whether the driver is in an abnormal state based on the first threshold time T1. That is, it determines whether at least one of the first state, the second state, or the third state described above continues for the first threshold time T1 or more. If the determination result is negative (No), the ECU 10 returns from this routine. On the other hand, if the determination result is positive (Yes), the ECU 10 proceeds to step S240, determines that the driver is in an abnormal state, and returns from this routine.

[0044] 5 is a flowchart illustrating a routine for processing PCS control by the CUP 11 of the ECU 10. This routine is started when the vehicle SV starts to move, and is executed in parallel with the routines for each process shown in FIGS.

[0045] In step S300, the ECU 10 acquires coordinate information of an object present in the area ahead of the host vehicle SV based on target information transmitted from the external sensor device 40. Next, in step S310, the ECU 10 calculates the trajectory of the host vehicle SV based on the detection results of the vehicle speed sensor 31, the steering angle sensor 34, and the yaw rate sensor 35. Note that the processing of steps S300 and S310 may be performed in any order, or may be performed simultaneously.

[0046] In step S320, the ECU 10 determines whether an object ahead of the host vehicle SV is an obstacle that may collide with the host vehicle SV. If the object is a moving object, the ECU 10 determines the moving object to be an obstacle if the trajectory of the moving object intersects with the trajectory of the host vehicle SV. Also, if the object is a stationary object, the ECU 10 determines the stationary object to be an obstacle if the trajectory of the host vehicle SV intersects with the current position of the stationary object. If the ECU 10 determines that the object ahead of the host vehicle SV is an obstacle (Yes), the ECU 10 proceeds to processing of step S330. On the other hand, if the ECU 10 determines that the object ahead of the host vehicle SV is not an obstacle (No), the ECU 10 returns from this routine.

[0047] In step S330, the ECU 10 calculates the TTC (=L / vr) by dividing the distance L from the host vehicle SV to the obstacle by the relative speed Vr. Next, in step S340, the ECU 10 determines whether the TTC is equal to or less than the collision determination threshold Tv. If the TTC is equal to or less than the collision determination threshold Tv (Yes), the ECU 10 proceeds to the processing of step S350. On the other hand, if the TTC is greater than the collision determination threshold Tv (No), the ECU 10 returns from this routine.

[0048] In step S350, the ECU 10 determines whether the driver is determined to be in an abnormal state by the driver abnormality determination process described above. If the driver is determined to be in an abnormal state (Yes), the ECU 10 proceeds to the process of step S360.

[0049] In step S360, the ECU 10 determines whether or not there is a high possibility that the host vehicle SV will collide with an obstacle based on a second mitigation threshold time T2' (=T2-Td2) obtained by subtracting a predetermined amount Td2 from the second threshold time T1. Specifically, the ECU 10 determines whether or not the state in which the TTC is equal to or less than the collision determination threshold Tv continues for the second mitigation threshold time T2' or more. If the determination result is negative (No), the ECU 10 returns from this routine. On the other hand, if the determination result is positive (Yes), the ECU 10 proceeds to step S380, issues a warning and executes deceleration control, and then returns from this routine.

[0050] If the determination in step S350 is negative (No), that is, if the driver is not determined to be in an abnormal state, the ECU 10 proceeds to processing in step S370. In step S370, the ECU 10 determines whether or not there is a high possibility that the host vehicle SV will collide with an obstacle based on the second threshold time T2. Specifically, it determines whether or not the state in which the TTC is equal to or less than the collision determination threshold Tv continues for the second threshold time T2 or more. If the determination result is negative (No), the ECU 10 returns from this routine. On the other hand, if the determination result is positive (Yes), the ECU 10 proceeds to step S380, issues a warning and executes deceleration control, and then returns from this routine.

[0051] According to the present embodiment described above in detail, when the distracted state determination unit 120 determines that the driver is in a distracted state while the ACC or LTA is operating, the driver state determination unit 130 relaxes the determination conditions by shortening the first threshold time T1 used to determine whether the driver is in an abnormal state. This makes it possible to detect a driver abnormality early when the driver actually becomes distracted due to the use of the ACC or LTA. Furthermore, when the driver state determination unit 130 determines that the driver is in an abnormal state, the PCS control unit 140 relaxes the execution conditions by shortening the second threshold time T2 used to determine whether deceleration control or an alarm is to be executed. This allows for earlier deceleration control or alarm activation by PCS control when a driver abnormality is detected, thereby reliably improving safety.

[0052] The above describes the driver monitoring device and driver monitoring method according to this embodiment, but the present disclosure is not limited to the above embodiment, and various modifications are possible as long as they do not deviate from the purpose of the present invention.

[0053] For example, in the above embodiment, the PCS control has been described as an example of deceleration control, but it may also be steering avoidance control that automatically controls the steering angle of the steered wheels of the vehicle to avoid a collision with an obstacle. Furthermore, the driving assistance is not limited to ACC or LTA, and may be other driving assistance. [Explanation of symbols]

[0054] 10...ECU, 20...drive device, 21...steering device, 22...braking device, 30...internal sensor device, 40...external sensor device, 50...driver monitoring device, 60...ACC operation unit, 65...LTA start switch, 95...speaker, 98...wireless communication device, 100...ACC control unit, 110...LTA control unit, 120...distraction state determination unit, 130...driver state determination unit, 140...PCS control unit

Claims

1. A driver monitoring device applied to a vehicle equipped with a driving assistance device capable of executing predetermined driving assistance to assist a driver in driving, a driver state acquisition unit that acquires a state of the driver, the driver state acquisition unit having a driver camera that captures an image of the face of the driver and a steering touch sensor that detects whether the driver is gripping a steering wheel; a distracted state determination unit that determines that the driver is in a distracted state where the driver is not paying attention to the surroundings when the steering touch sensor of the driver state acquisition unit does not detect the driver continuously gripping the steering wheel during a predetermined time period after the driver starts using the driving assistance; a driver state determination unit that determines that the driver is in an abnormal state when the line of sight state of the driver acquired by the driver camera included in the driver state acquisition unit continues to be in a predetermined state for a predetermined first threshold time or more, When the driving assistance device is performing the driving assistance, if the distracted state determination unit determines that the driver is in the distracted state, the driver state determination unit relaxes the determination condition for determining whether the driver is in an abnormal state based on a first relaxed threshold time obtained by subtracting a predetermined amount from the first threshold time. Driver monitoring devices.

2. 2. The driver monitoring device according to claim 1, The abnormal state includes at least the driver looking away, falling asleep, or having a seizure. Driver monitoring devices.

3. 3. The driver monitoring device according to claim 1 or 2, The driving assistance device is configured to be able to execute collision avoidance control for avoiding a collision between the vehicle and the obstacle or mitigating damage caused by the collision when the obstacle ahead of the vehicle continues to satisfy a predetermined collision condition for a predetermined second threshold time or more, and when the driver state determination unit determines that the driver is in the abnormal state, shorten the second threshold time. Driver monitoring devices.

4. A driver monitoring device according to claim 1 or 2, The driver condition determination unit increases the predetermined amount as the vehicle speed of the vehicle increases. Driver monitoring devices.

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