Vehicle control device, vehicle control method, and vehicle control computer program

Abstract

To provide a vehicle control device capable of suppressing instability of vehicle control due to fogging on a windshield of a vehicle.SOLUTION: A vehicle control device includes: a fogging determination section 31 for determining whether fog is generated on a windshield of a vehicle 10 or whether a sign of fogging exists, based on a fogging sensor signal which is the signal by a fogging sensor 2 arranged in the vehicle 10 and expresses a physical index related to a fogging degree of the windshield of the vehicle 10 or based on an operation of an on-vehicle unit 6 capable of performing a defogging operation of the vehicle 10; and a level control section 33 for changing a level of operation control applicable to the vehicle, so as to increase a participation degree in an operation by a driver of the vehicle 10 or to reduce the participation degree in response to the level of the operation control during application to the vehicle 10 when it is determined that fog is generated on the windshield of the vehicle 10 or the sign of fogging exists.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a vehicle control device, a vehicle control method, and a computer program for vehicle control. [Background technology]

[0002] In order to control the automatic driving of a vehicle or to assist the driver in driving, it is necessary to be able to monitor the situation around the vehicle using on-board sensors. However, depending on the environment around the vehicle, it may be difficult to monitor the situation around the vehicle. Therefore, a technology has been proposed that switches the appropriateness of driving assistance control depending on the backlight situation (see, for example, Patent Document 1). Furthermore, a technology has been proposed that supports the operation of air conditioning that is effective in clearing fog before the vehicle windows fog up (see, for example, Patent Document 2).

[0003] The driving assistance device disclosed in Patent Document 1 sets conditions for starting or canceling the temporary suspension of driving assistance control for the vehicle based on the yaw rate or yaw angle of the vehicle when backlight is detected. The driving assistance device then performs driving assistance control for the vehicle based on information about a specific target detected from a captured image, and starts or cancels the temporary suspension of driving assistance control in accordance with the set conditions.

[0004] Furthermore, the vehicle information display device disclosed in Patent Document 2 determines whether or not it is advisable to perform an operation to defog the windows based on the vehicle's air conditioning status and vehicle conditions. If the vehicle information display device determines that window fogging will occur, it highlights the air conditioning operation to defog the windows on the display unit. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2009-241648 [Patent Document 2] Japanese Patent Application Laid-Open No. 2006-341753 Summary of the Invention [Problem to be solved by the invention]

[0006] Even when a driver is prompted to defog the vehicle's windows, the driver may not perform the operation for some reason. In such a case, the windows become fogged, making it difficult to monitor the situation around the vehicle. This makes it difficult to continue automatic driving control or driving assistance, resulting in unstable vehicle control. Furthermore, if driving control is transferred to the driver or application of driving assistance is stopped after it becomes difficult to monitor the situation around the vehicle, the driver may be forced to drive the vehicle under difficult driving conditions.

[0007] SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a vehicle control device that can prevent unstable vehicle control due to fogging of the vehicle windows. [Means for solving the problem]

[0008] According to one embodiment, there is provided a vehicle control device including a fogging determination unit that determines whether fogging has occurred on the vehicle window or whether there are signs of fogging based on a fogging sensor signal indicating a physical index related to the degree of fogging on the vehicle window, which is output by a fogging sensor provided in the vehicle, or on the operation of an on-board device capable of performing a fogging operation, and a level control unit that, when it is determined that fogging has occurred on the vehicle window or there are signs of fogging, changes the level of driving control applicable to the vehicle so as to increase the degree of driver involvement in driving or suppress a decrease in the degree of driver involvement, depending on the level of driving control currently applied to the vehicle.

[0009] In this vehicle control device, when the level of driving control being applied to the vehicle is a level that requires driving operation from the driver, it is preferable that the level control unit suppresses a decrease in the degree of driver involvement in driving by prohibiting the application of a level of driving control that does not require driving operation from the driver.

[0010] In addition, in this vehicle control device, when the level of driving control being applied to the vehicle is a level at which driving control is executed without the driver's involvement in driving, it is preferable that the level control unit increases the degree of driver involvement in driving by changing the level of driving control to a level that requires the driver to monitor the vehicle's surroundings.

[0011] In this case, the vehicle control device preferably further includes a notification unit that, when it is determined that there is a possibility of the windows fogging up, notifies the driver via a notification device provided in the vehicle that it is difficult to continue automatic driving control of the vehicle.The level control unit preferably changes the applicable driving control level to a level that requires the driver to monitor the surroundings of the vehicle after a predetermined grace period has elapsed since the notification.

[0012] Alternatively, the vehicle control device preferably further includes a notification unit that, when it is determined that there is a possibility of the vehicle windows fogging up, notifies the driver via a notification device provided in the vehicle to perform an operation to cause the in-vehicle device to perform a defogging operation.The level control unit preferably changes the level of driving control applicable to the vehicle so as to increase the degree of involvement of the driver in driving the vehicle if the in-vehicle device does not perform the defogging operation even after a predetermined grace period has elapsed since the notification and the signs of fogging on the vehicle windows remain.

[0013] Furthermore, it is preferable that the on-board equipment is an air conditioning unit, and the fogging determination unit determines that there are signs of fogging on the vehicle's windows when the air conditioning unit is not currently performing an anti-fogging operation and when the air conditioning unit has performed an anti-fogging operation within the most recent specified period.

[0014] According to another embodiment, there is provided a vehicle control method including: determining whether a vehicle window is fogging or there is a sign of fogging based on a fogging sensor signal indicating a physical index related to a fogging level of the vehicle window, the fogging sensor signal being obtained by a fogging sensor provided in the vehicle, or the operation of an on-board device capable of performing a fogging operation; and, when it is determined that the vehicle window is fogging or there is a sign of fogging, changing a level of driving control applicable to the vehicle so as to increase a degree of driver involvement in driving or suppress a decrease in the degree of driver involvement, according to a level of driving control currently applied to the vehicle.

[0015] According to yet another embodiment, there is provided a vehicle control computer program, the vehicle control computer program including instructions to cause a processor mounted on the vehicle to determine whether fogging has occurred or there are signs of fogging on a vehicle window based on a fogging sensor signal indicating a physical index related to the degree of fogging on the vehicle window obtained by a fogging sensor provided on the vehicle or the operation of an on-board device capable of performing a fogging operation, and, when it is determined that fogging has occurred or there are signs of fogging on the vehicle window, change the level of driving control applicable to the vehicle so as to increase the degree of driver involvement in driving or suppress a decrease in the degree of driver involvement in driving, depending on the level of driving control currently applied to the vehicle. [Effects of the Invention]

[0016] The vehicle control device according to the present disclosure has the effect of suppressing instability in vehicle control due to fogging of the vehicle windows. [Brief explanation of the drawings]

[0017] [Figure 1] 1 is a schematic configuration diagram of a vehicle control system including a vehicle control device. [Figure 2] FIG. 2 is a hardware configuration diagram of an ECU, which is an example of a vehicle control device. [Figure 3]FIG. 2 is a functional block diagram of a processor of an ECU related to vehicle control processing. [Figure 4] FIG. 10 is a diagram illustrating an example of the relationship between fogging determination and changes in vehicle control level. [Figure 5] 4 is an operational flowchart of a vehicle control process. DETAILED DESCRIPTION OF THE INVENTION

[0018] Hereinafter, a vehicle control device, a vehicle control method, and a vehicle control computer program executed by the vehicle control device will be described with reference to the drawings. The vehicle control device determines whether or not a vehicle window (e.g., a front window or rear window of the vehicle interior, hereinafter simply referred to as a window) is fogging or has signs of fogging. If the vehicle control device determines that the window is fogging or has signs of fogging, it degrades the automated driving control of the vehicle depending on the level of driving control currently being applied to the vehicle. That is, if the vehicle control device detects fogging or signs of fogging on the window, it increases the degree of driver involvement in vehicle control or suppresses a decrease in the degree of driver involvement depending on the level of driving control currently being applied to the vehicle. In this way, the vehicle control device suppresses unstable vehicle control caused by fogging on the window.

[0019] FIG. 1 is a schematic diagram of a vehicle control system including a vehicle control device. The vehicle control system 1 mounted on a vehicle 10 includes a fogging sensor 2, an external sensor 3, a notification device 4, and an electronic control unit (ECU) 5, which is an example of a vehicle control device. The fogging sensor 2, the external sensor 3, the notification device 4, and the ECU 5 are communicatively connected to each other via an in-vehicle network conforming to a communication standard such as a controller area network. Furthermore, the ECU 5 is connected to an air conditioner 6 for adjusting the temperature and humidity in the passenger compartment of the vehicle 10 via the in-vehicle network. The air conditioner 6 is an example of an in-vehicle device capable of performing an anti-fogging operation. Furthermore, the vehicle control system 1 may include a navigation device (not shown), a wireless communication device (not shown), and a receiver (not shown), such as a GPS receiver, that receives signals from a satellite positioning system to determine the position of the vehicle 10.

[0020] The fogging sensor 2 measures a physical index related to the degree of fogging of the window at predetermined intervals and generates a fogging sensor signal representing the measured value. In this embodiment, the fogging sensor 2 is a humidity sensor that is installed in the passenger compartment of the vehicle 10 and measures the humidity inside the passenger compartment of the vehicle 10 as a physical index related to the degree of fogging. The fogging sensor 2 then generates a signal representing the measured value of the humidity inside the passenger compartment as the fogging sensor signal.

[0021] Every time the fogging sensor 2 generates a fogging sensor signal, the fogging sensor 2 outputs the generated fogging sensor signal to the ECU 5 via the in-vehicle network.

[0022] The exterior sensor 3 generates an exterior sensor signal representing the situation around the vehicle 10 at predetermined intervals. The exterior sensor 3 may be, for example, a camera installed inside the vehicle 10 to capture an image of a predetermined area outside the vehicle 10 (for example, the area in front of the vehicle 10). In this case, the exterior sensor signal is an image representing the predetermined area. Alternatively, the exterior sensor 3 may be a distance measurement sensor, such as a LiDAR or radar, that measures the distance to an object around the vehicle 10. In this case, the exterior sensor signal is a distance measurement signal representing the distance to the object in each direction within a predetermined distance measurement range. Furthermore, multiple exterior sensors 3 with different image capture directions or distance measurement ranges may be installed on the vehicle 10.

[0023] Every time the vehicle exterior sensor 3 generates a vehicle exterior sensor signal, the vehicle exterior sensor 3 outputs the generated vehicle exterior signal to the ECU 5 via the in-vehicle network.

[0024] The notification device 4 is provided in the passenger compartment of the vehicle 10 and is a device that provides a predetermined notification to the driver by light, sound, text display, or image display. To achieve this, the notification device 4 has, for example, at least one of a speaker, a light source, or a display device. When the notification device 4 receives a notification for the driver from the ECU 5, it notifies the driver of the notification by sound from the speaker, by emitting or flashing light from the light source, or by displaying a notification on the display device.

[0025] The ECU 5 performs automatic driving control of the vehicle 10 when an operation to control the automatic driving of the vehicle 10 is performed via an operation switch (not shown) provided in the passenger compartment of the vehicle 10. The ECU 5 also determines whether or not there is fogging or signs of fogging on the window based on a fogging sensor signal or a signal indicating the operation of the air conditioning device, and adjusts the degree of driver involvement in the control of the vehicle 10 according to the determination result and the state of the automatic driving control.

[0026] Fig. 2 is a hardware configuration diagram of the ECU 5. As shown in Fig. 2, the ECU 5 has a communication interface 21, a memory 22, and a processor 23. The communication interface 21, the memory 22, and the processor 23 may be configured as separate circuits, or may be configured integrally as a single integrated circuit.

[0027] The communication interface 21 has an interface circuit for connecting the ECU 5 to the in-vehicle network. Every time the communication interface 21 receives a fogging sensor signal from the fogging sensor 2, it passes the fogging sensor signal to the processor 23. Every time the communication interface 21 receives an outside-vehicle sensor signal from the outside-vehicle sensor 3, it passes the outside-vehicle sensor signal to the processor 23. Furthermore, every time the communication interface 21 receives an operation signal indicating the operating status from the air conditioner 6, it passes the operation signal to the processor 23. Furthermore, when the communication interface 21 receives a notification to the driver from the processor 23, it outputs the notification to the notification device 4.

[0028] The memory 22 is an example of a storage unit and includes, for example, a volatile semiconductor memory and a nonvolatile semiconductor memory. The memory 22 stores various algorithms and various data used in the vehicle control process executed by the processor 23 of the ECU 5. For example, the memory 22 stores various parameters used to determine whether fogging is present and messages to notify the driver. The memory 22 also temporarily stores the fogging sensor signal and the outside sensor signal received within a recent fixed period, a flag indicating the level of driving control currently being applied, and various data generated during the vehicle control process.

[0029] The processor 23 includes one or more central processing units (CPUs) and their peripheral circuits. The processor 23 may further include other arithmetic circuits such as a logic unit, a numerical calculation unit, or a graphics processing unit. The processor 23 executes vehicle control processing.

[0030] 3 is a functional block diagram of the processor 23 related to vehicle control processing. The processor 23 has a fogging determination unit 31, a notification unit 32, a level control unit 33, and a vehicle control unit 34. Each of these units in the processor 23 is a functional module realized by, for example, a computer program running on the processor 23. Alternatively, each of these units in the processor 23 may be a dedicated arithmetic circuit provided separately in the processor 23.

[0031] The fogging determination unit 31 determines whether fogging has occurred on the window or whether there are signs of fogging based on the fogging sensor signal. As described above, in this embodiment, the fogging sensor signal represents the measured humidity value inside the vehicle 10, so the fogging determination unit 31 determines that fogging has occurred on the window when the measured humidity value is higher than the fogging determination threshold. Furthermore, the fogging determination unit 31 determines that there are signs of window fogging when the measured humidity value is higher than the fogging prediction threshold. The fogging prediction threshold is set to a value lower than the fogging determination threshold for determining that the window is actually fogging.

[0032] Alternatively, the fogging determination unit 31 predicts future changes in humidity over time by extrapolating the changes in humidity measured over the most recent predetermined period. If the predicted humidity becomes higher than the fogging determination threshold within a certain period, the fogging determination unit 31 determines that there is a sign of fogging on the window.

[0033] Furthermore, the fogging determination unit 31 may determine whether there are signs of window fogging based on an operation signal received from the air conditioner 6. For example, if the air conditioner 6 performs a defogging operation immediately after the vehicle 10 starts to drive, even if the window is not fogging up when the operation ends, the window may fog up again depending on the environment around the vehicle 10. Therefore, the fogging determination unit 31 may determine that there are signs of window fogging when the operation signal received from the air conditioner 6 indicates that the air conditioner 6 has performed a defogging operation within the most recent predetermined period.

[0034] The fogging determination unit 31 notifies the notification unit 32 and the level control unit 33 of the determination result as to whether fogging has occurred on the window or whether there are signs of fogging. Furthermore, when the fogging determination unit 31 determines fogging based on a predicted humidity value, it also notifies the notification unit 32 of the predicted time until the predicted humidity becomes higher than the fogging determination threshold.

[0035] When the notification unit 32 receives a determination result from the fogging determination unit 31 that fogging has occurred on the window or that there is a sign of fogging, the notification unit 32 outputs to the notification device 4 a notification (hereinafter referred to as a defogging operation notification) urging the driver to operate an in-vehicle device such as the air conditioner 6 to perform a defogging operation. At this time, the notification unit 32 may include in the defogging operation notification a message indicating a grace period for operating the in-vehicle device to perform the defogging operation. Furthermore, when autonomous driving control is being applied to the vehicle 10, the notification unit 32 may include in the defogging operation notification a message indicating that it will be difficult to continue the autonomous driving control. Furthermore, when autonomous driving control is not being applied to the vehicle 10, the notification unit 32 may include in the defogging operation notification a message indicating that it will be difficult to apply the autonomous driving control. In this way, the notification unit 32 can notify the driver that it will be difficult to continue or apply the autonomous driving control unless the in-vehicle device performs a defogging operation.

[0036] When a fogging determination is made based on a predicted humidity value, the notification unit 32 may advance the timing of the defogging operation notification the shorter the predicted time until the predicted humidity becomes higher than the fogging determination threshold. That is, the notification unit 32 may set the timing of the defogging operation notification so that the shorter the predicted time, the shorter the grace period from the timing of the defogging operation notification until the predicted humidity becomes higher than the fogging determination threshold. In this way, the notification unit 32 can increase the driver's level of involvement in driving before the window actually becomes fogged, thereby more appropriately suppressing unstable driving control of the vehicle 10.

[0037] The notification unit 32 notifies the level control unit 33 that the defogging operation notification has been notified to the driver via the notification device 4. Furthermore, when the notification unit 32 is notified by the level control unit 33 about a change in the applicable driving control level, the notification unit 32 outputs the notification to the notification device 4.

[0038] The level control unit 33 determines whether an in-vehicle device capable of performing a defogging operation has performed the defogging operation within a predetermined grace period after the defogging operation notification is issued to the driver via the notification device 4. When the ECU 5 receives a signal indicating that the defogging operation has been performed from the in-vehicle device capable of performing the defogging operation, the level control unit 33 determines that the in-vehicle device has performed the defogging operation. Note that the in-vehicle device capable of performing the defogging operation may be, for example, the air conditioner 6 or a de-icer. The defogging operation performed by the in-vehicle device may be, for example, the operation of a defogger by the air conditioner 6 or the operation of a de-icer.

[0039] If the on-board device has not performed the defogging operation even after a predetermined grace period has elapsed since the defogging operation notification was issued, the level control unit 33 determines whether the window signs of fogging have disappeared. The term "window signs of fogging not disappeared" includes cases where the window remains fogged. For example, the level control unit 33 determines that the window signs of fogging have not disappeared if the humidity is higher than the defogging threshold after the predetermined grace period has elapsed. The defogging threshold is preferably set to a value higher than the fogging sign threshold and lower than the fogging determination threshold. Alternatively, the level control unit 33 may predict a change in humidity after the predetermined grace period has elapsed using a process similar to that of the fogging determination unit 31. The level control unit 33 may determine that the window signs of fogging have not disappeared if the predicted humidity value becomes higher than the fogging determination threshold within a certain period after the defogging operation notification was issued.

[0040] If a predetermined grace period has elapsed since the issuance of the defogging operation notification and the signs of window fogging have not been resolved, the level control unit 33 checks the level by referring to a flag that indicates the level of driving control currently being applied to the vehicle 10, which is stored in the memory 22. The level control unit 33 then degrades the autonomous driving control of the vehicle according to the level of driving control currently being applied. That is, the level control unit 33 changes the applicable level of driving control so as to increase the degree of driver involvement in driving of the vehicle 10 or suppress a decrease in the degree of driver involvement in driving. The level control unit 33 then outputs a notification according to the changed level to the notification unit 32, thereby notifying the driver of a request according to the changed level.

[0041] For example, assume that automated driving control at a level where driving control is performed without the involvement of the driver (e.g., level 3 defined by the Society of Automotive Engineers (SAE)) is applied to the vehicle 10. In this case, the level control unit 33 changes the level of driving control applicable to the vehicle 10 to a level where the driver is not required to operate the vehicle 10 but is required to monitor the surroundings of the vehicle 10 (e.g., level 2 defined by the SAE). Furthermore, when level 2 driving control is applied to the vehicle 10, the level control unit 33 changes the level to a level where the ECU 5 continues driving control on the condition that the driver holds the steering wheel of the vehicle 10. Note that this is not limited to this, and the level control unit 33 may change the applicable level of driving control to a level where a driving operation by the driver is required (i.e., level 0 or level 1 defined by the SAE) when the level of driving control currently being applied is level 3 or level 2. Furthermore, when the level of driving control being applied is a level that requires driving operation by the driver (i.e., when the level of driving control being applied is level 0 or level 1), the level control unit 33 does not permit the application of driving control at a level that does not require driving operation by the driver. In other words, the level control unit 33 does not apply driving control at level 2 or higher.

[0042] When fogging is determined based on the predicted humidity value, the level control unit 33 may shorten the grace period as the predicted time until the predicted humidity becomes higher than the fogging determination threshold becomes shorter, similar to the notification unit 32. In this way, the level control unit 33 can increase the degree of driver involvement in driving until the window actually fogs up, and more appropriately prevent the driving control of the vehicle 10 from becoming unstable.

[0043] FIG. 4 is a diagram showing an example of the relationship between fogging determination and changes in vehicle control level. In FIG. 4, the horizontal axis represents time. In the example shown in the upper part of FIG. 4, at time t1, it is determined that there is a sign of window fogging, and a defogging operation notification is issued to the driver via the notification device 4. Thereafter, at time t2, before the grace period P has elapsed, an on-board device such as the air conditioner 6 starts to perform a defogging operation. Therefore, the currently applied driving control level is not changed, and the driving control continues. Furthermore, if a driving control level higher than the currently applied level can be applied to the vehicle 10 due to the circumstances around the vehicle 10, changing to the higher level of driving control is not prohibited.

[0044] In the example shown in the lower part of Fig. 4, it is also determined at time t1 that there is a sign of window fogging, and a defogging operation notification is issued to the driver via notification device 4. However, in this example, the on-board device does not subsequently execute the defogging operation, even after grace period P has elapsed. Therefore, at time t3 after grace period P has elapsed, if the sign of window fogging has not been resolved, the applicable driving control level is changed to increase the driver's level of involvement in driving or to prevent a decrease in the driver's level of involvement in driving. Then, the driver is notified of requirements for the changed level.

[0045] The vehicle control unit 34 performs automatic driving control of the vehicle 10 according to the level of driving control applied to the vehicle 10.

[0046] For example, when level 3 driving control is applied, the vehicle control unit 34 detects lane markings that define the lane in which the vehicle 10 is traveling (hereinafter referred to as the host lane) and objects (other vehicles, pedestrians, etc.) that exist around the vehicle 10 from the external sensor signals obtained by the external sensor 3. Then, the vehicle control unit 34 sets a planned travel trajectory along which the vehicle 10 is scheduled to travel in a section from the current position of the vehicle 10 to a predetermined distance ahead, based on the detected lane markings and moving objects. The planned travel trajectory is set, for example, as a set of target positions of the vehicle 10 at each point in time. For example, the vehicle control unit 34 sets the planned travel trajectory so that the vehicle 10 does not collide with surrounding objects and travels along the host lane. Then, the vehicle control unit 34 controls each unit of the vehicle 10 so that the vehicle 10 travels along the set planned travel trajectory.

[0047] In this case, the vehicle control unit 34 can detect objects and lane markings around the vehicle 10 by inputting the external sensor signals to a classifier that has been trained in advance to detect objects and lane markings around the vehicle 10 from the external sensor signals. The vehicle control unit 34 can use, as such a classifier, a so-called deep neural network (hereinafter simply referred to as DNN) having a convolutional neural network (hereinafter simply referred to as CNN) type architecture. Such a classifier is trained in advance according to a learning method such as backpropagation using a large number of training images that depict the objects or lane markings to be detected.

[0048] Note that the vehicle control unit 34 may determine whether or not the predetermined condition is satisfied when Level 3 is permitted to be applied only when the driving environment of the vehicle 10 satisfies a predetermined condition. For example, when Level 3 is permitted to be applied only when the area around the vehicle 10 is congested, the vehicle control unit 34 may determine whether or not the area around the vehicle 10 is congested. In this case, the vehicle control unit 34 determines that the area around the vehicle 10 is congested when the speed of the vehicle 10 measured by a vehicle speed sensor (not shown) satisfies a predetermined congestion condition. Alternatively, the vehicle control unit 34 may determine that the area around the vehicle 10 is congested when the speed of other vehicles estimated by tracking other vehicles traveling around the vehicle 10 detected based on an external sensor signal satisfies a predetermined congestion condition. Alternatively, the vehicle control unit 34 may determine that the area around the vehicle 10 is congested when the current position of the vehicle 10 determined by a GPS receiver (not shown) is included in a congested section indicated by traffic information received via a wireless communication device (not shown).

[0049] Furthermore, when the vehicle control unit 34 performs autonomous driving control of the vehicle 10 on the condition that the driver monitors the surroundings of the vehicle 10, the vehicle control unit 34 acquires an image of the driver (hereinafter referred to as a driver image) from a driver monitor camera (not shown) installed in the vehicle cabin. The vehicle control unit 34 then determines whether the driver is monitoring the surroundings of the vehicle 10 by detecting the driver's line of sight or the driver's facial orientation from the driver image. Only when the driver is monitoring the surroundings of the vehicle 10, the vehicle control unit 34 controls the driving of the vehicle 10, as in the case of applying Level 3 described above. The vehicle control unit 34 may detect the line of sight or the facial orientation of the driver depicted in the image using any of a variety of methods. For example, the vehicle control unit 34 may detect the corneal reflection image of a light source illuminating the driver and the center of the driver's pupil from the driver image, and detect the driver's line of sight based on the positional relationship between the corneal reflection image and the center of the pupil.

[0050] Furthermore, when the vehicle control unit 34 controls the vehicle 10 to operate automatically on the condition that the driver holds the steering wheel, it only needs to determine whether the driver is holding the steering wheel based on a signal from a contact sensor (not shown) provided on the steering wheel.

[0051] 5 is an operational flowchart of the vehicle control process executed by the processor 23. The processor 23 may execute the vehicle control process in accordance with the following operational flowchart at predetermined intervals.

[0052] The fogging determination unit 31 of the processor 23 determines whether fogging has occurred on the window or whether there are signs of fogging based on the fogging sensor signal (step S101). If it is determined that the window is not fogging and there are no signs of fogging (step S101-No), the vehicle control unit 34 of the processor 23 continues driving control of the vehicle 10 at the currently applied driving control level (step S102). As described above, if a driving control level higher than the currently applied driving control level can be applied depending on the circumstances around the vehicle 10, changing to the higher level of driving control is not prohibited.

[0053] On the other hand, if it is determined that the window is fogging up or there is a sign of fogging up (step S101-Yes), the notification unit 32 of the processor 23 notifies the driver of a defogging operation notification via the notification device 4 (step S103).

[0054] After step S103, the level control unit 33 of the processor 23 determines whether or not the defogging operation has been performed by the in-vehicle device within a predetermined grace period after the defogging operation notification has been notified to the driver (step S104). If the defogging operation has been performed within the grace period (step S104-Yes), the vehicle control unit 34 continues to control the driving of the vehicle 10 at the currently applied control level (step S102).

[0055] On the other hand, if the defogging operation has not been performed even after the grace period has elapsed (step S104-No), the level control unit 33 determines whether the signs of fogging on the window have disappeared (step S105).If the signs of fogging on the window have disappeared (step S105-Yes), the vehicle control unit 34 continues to control the operation of the vehicle 10 at the currently applied control level (step S102).

[0056] On the other hand, if the signs of window fogging have not been resolved (step S105-No), the level control unit 33 refers to the state of the autonomous driving control currently being applied to the vehicle 10. Then, the level control unit 33 changes the applicable level of driving control depending on the state of the autonomous driving control currently being applied, so as to increase the degree of driver involvement in driving or suppress a decrease in the degree of involvement (step S106). The vehicle control unit 34 executes the set level of autonomous driving control for the vehicle 10 (step S107).

[0057] After step S102 or S107, processor 23 ends the vehicle control process.

[0058] As described above, the vehicle control device determines whether the vehicle windows are fogging or there are signs of fogging. If the vehicle control device determines that the windows are fogging or there are signs of fogging, the vehicle control device changes the applicable driving control level to increase the degree of driver involvement in vehicle control or suppress a decrease in the degree of driver involvement, depending on the state of automatic driving control of the vehicle. This allows the vehicle control device to suppress instability in vehicle control when the vehicle windows are fogging. Furthermore, the vehicle control device notifies the driver that it will cause the in-vehicle device to perform a defogging operation before the vehicle windows actually fogging up, thereby suppressing actual fogging of the vehicle windows and enabling the driving control at the currently applied level to be continued.

[0059] According to a modified example, the vehicle 10 may be provided with an interior temperature sensor that measures the temperature inside the vehicle 10 (hereinafter simply referred to as the interior temperature) and an exterior temperature sensor that measures the temperature outside the vehicle 10 (hereinafter simply referred to as the exterior temperature) as the fogging sensor 2. In this case, the physical indicators related to the degree of fogging are the interior temperature and the exterior temperature. The fogging determination unit 31 then determines whether there is a sign of window fogging based on a combination of the interior temperature and the exterior temperature. For example, the fogging determination unit 31 determines that there is a sign of window fogging when the difference between the interior temperature obtained as the fogging sensor signal and the interior temperature satisfies a fogging sign condition. The fogging sign condition may be set in advance and stored in the memory 22. On the other hand, when the difference does not satisfy the fogging sign condition, the fogging determination unit 31 determines that there is no sign of window fogging at the time of the determination. Similarly, if the defogging operation is not performed even after a predetermined grace period has elapsed since the execution of the defogging operation notification, and the difference between the temperature inside the vehicle and the temperature outside the vehicle does not satisfy the fogging warning condition, the level control unit 33 may determine that the signs of fogging for the window have been resolved.

[0060] Alternatively, the fogging determination unit 31 may further use one or more of the amount of rainfall per unit time, the wiper operation signal (not shown), weather information, and the number of people in the vehicle 10 to determine whether the window is fogging or whether there are signs of fogging. In this case, the fogging determination unit 31 may determine that there are signs of window fogging when the fogging sensor signal and these values ​​satisfy predetermined fogging signs conditions. The amount of rainfall per unit time is measured by a rain sensor (not shown) mounted on the vehicle 10. The weather information is acquired via a wireless communication device (not shown) mounted on the vehicle 10. Furthermore, the fogging determination unit 31 may detect the number of people in the vehicle 10 by inputting an interior image generated by a camera mounted on the vehicle 10 to capture an image of the interior of the vehicle 10 into a classifier that has been trained to detect people. Alternatively, the fogging determination unit 31 may detect the number of people in the vehicle 10 based on detection signals from pressure sensors (not shown) mounted on each seat in the vehicle 10 or signals indicating whether a seatbelt is fastened or unfastened.

[0061] According to yet another modification, when the level control unit 33 prohibits the application of the autonomous driving control because the in-vehicle device has performed a defogging operation for a recent predetermined period, the level control unit 33 may notify the driver via the notification device 4 of the remaining time until the prohibition on the application of the autonomous driving control is lifted. In this case, the level control unit 33, for example, calculates the remaining time until the prohibition on the application of the autonomous driving control is lifted based on the elapsed time since the air conditioner 6 started operating. For example, an estimated time from the start of operation of the air conditioner 6 until signs of fogging on the windows disappear is stored in the memory 22 in advance. Note that this estimated time may be set for each humidity level in the vehicle cabin when the air conditioner 6 started operating. The level control unit 33 then calculates the remaining time until the prohibition on the application of the autonomous driving control is lifted by subtracting the elapsed time from the start of operation of the air conditioner 6 to the current time from the estimated time. According to this modification, the driver can know the remaining time until automatic driving control can be applied, thereby improving convenience for the driver.

[0062] According to yet another modification, when it is determined that the window is fogging up or there are signs of fogging up, the level control unit 33 may immediately increase the degree of involvement of the driver in driving of the vehicle 10 or suppress a decrease in the degree of involvement of the driver in driving. The notification unit 32 may then output a notification regarding a change in the degree of involvement of the driver in driving to the notification device 4. According to this modification, the level control unit 33 can shorten the time from when it is determined that the window is fogging up or there are signs of fogging up to when it changes the degree of involvement of the driver in driving. Therefore, the level control unit 33 can suppress unstable autonomous driving control of the vehicle 10 even when the window is rapidly fogging up.

[0063] In addition, a computer program that realizes the functions of the processor 23 of the ECU 5 according to the above embodiment or variant may be provided in a form recorded on a computer-readable portable recording medium such as a semiconductor memory, a magnetic recording medium or an optical recording medium.

[0064] As described above, those skilled in the art can make various modifications to the embodiments within the scope of the present invention. [Explanation of symbols]

[0065] 1. Driving assistance systems 2 Fog sensor 3. Outside vehicle sensors 4 Notification device 5 Electronic control unit (vehicle control unit) 6 Air conditioner 10 vehicles 21 Communication Interface 22 Memory 23 processors 31 Cloudiness detection unit 32 Notification Department 33 Level control section 34 Vehicle control unit

Claims

1. a fogging determination unit that determines whether there is a sign of fogging on the window based on a fogging sensor signal that is obtained by a fogging sensor provided in the vehicle and indicates a physical index related to the degree of fogging on the window of the vehicle, or based on the operation of an on-board device capable of performing a fogging operation on the vehicle; a level control unit that, when it is determined that there is a sign of fogging on the window, changes the level of driving control applicable to the vehicle in accordance with the level of driving control currently being applied to the vehicle so as to increase the degree of involvement of the driver in driving of the vehicle or suppress a decrease in the degree of involvement; a notification unit that, when it is determined that there is a sign of fogging on the window, notifies the driver via a notification device provided in the vehicle that it is difficult to continue automatic driving control of the vehicle; the fog sensor signal represents a measurement of humidity within the vehicle's cabin; the fogging determination unit predicts a future time change in humidity inside the vehicle cabin based on the fogging sensor signal obtained during a recent predetermined period, calculates a predicted time until the humidity inside the vehicle cabin will become higher than a predetermined fogging determination threshold based on the predicted time change, and determines that there is a sign of fogging on the window if the predicted time change indicates that the humidity inside the vehicle cabin will become higher than the fogging determination threshold within a certain future period, the level control unit changes the level of the driving control to a level that requires the driver to monitor the surroundings of the vehicle when a predetermined grace period has elapsed since the notification was made, and sets the predetermined grace period to a shorter time as the predicted time is shorter. Vehicle control device.

2. 2. The vehicle control device according to claim 1, wherein the level control unit, when the level of driving control being applied to the vehicle is a level that requires driving operation by the driver, suppresses the decrease in the degree of involvement by prohibiting the application of a level of driving control that does not require driving operation by the driver.

3. A fogging determination unit that determines whether there is a sign of fogging on the window based on a fogging sensor signal obtained by a fogging sensor installed in the vehicle and indicating a physical index related to the degree of fogging on the window of the vehicle, or based on the operation of an on-board device of the vehicle that is capable of performing an anti-fogging operation; a level control unit that, when it is determined that there is a sign of fogging on the window, changes the level of driving control applicable to the vehicle in accordance with the level of driving control currently being applied to the vehicle so as to increase the degree of involvement of the driver in driving of the vehicle or suppress a decrease in the degree of involvement; a notification unit that notifies the driver, via a notification device provided in the vehicle, that the driver should perform an operation to cause the in-vehicle device to perform a defogging operation when it is determined that there is a sign of fogging on the window; and the fog sensor signal represents a measurement of humidity within the vehicle's cabin; the fogging determination unit predicts a future time change in humidity inside the vehicle cabin based on the fogging sensor signal obtained during a recent predetermined period, calculates a predicted time until the humidity inside the vehicle cabin will become higher than a predetermined fogging determination threshold based on the predicted time change, and determines that there is a sign of fogging on the window if the predicted time change indicates that the humidity inside the vehicle cabin will become higher than the fogging determination threshold within a certain future period, When the defogging operation of the in-vehicle device is not performed and the sign of fogging on the window is not resolved even after a predetermined grace period has elapsed since the notification, the level control unit changes the level of the driving control applicable to the vehicle so as to increase the degree of involvement of the driver of the vehicle in driving, and sets the predetermined grace period to a shorter time as the predicted time is shorter. Vehicle control device.

4. determining whether there is a sign of fogging on the window based on a fogging sensor signal obtained by a fogging sensor provided in the vehicle and indicating a physical index related to the degree of fogging on the window of the vehicle, or based on the operation of an on-board device capable of performing a fogging operation on the vehicle; When it is determined that there is a sign of fogging on the window, the level of driving control applicable to the vehicle is changed in accordance with the level of driving control currently being applied to the vehicle, so as to increase the degree of involvement of the driver of the vehicle in driving or suppress a decrease in the degree of involvement; When it is determined that there is a sign of fogging on the window, the driver is notified via a notification device provided in the vehicle that it is difficult to continue the automatic driving control of the vehicle. This includes: the fog sensor signal represents a measurement of humidity within the vehicle's cabin; Determining whether there is a sign of fogging on the window includes predicting a future time change in humidity inside the vehicle cabin based on the fogging sensor signal obtained in a recent predetermined period, calculating a predicted time until the humidity inside the vehicle cabin will become higher than a predetermined fogging determination threshold based on the predicted time change, and determining that there is a sign of fogging on the window if the predicted time change indicates that the humidity inside the vehicle cabin will become higher than the fogging determination threshold within a certain future period. Changing the level of driving control applicable to the vehicle includes changing the level of driving control to a level that requires the driver to monitor the surroundings of the vehicle after a predetermined grace period has elapsed since the notification, and setting the predetermined grace period to a shorter time as the predicted time is shorter. Vehicle control method.

5. determining whether there is a sign of fogging on the window based on a fogging sensor signal obtained by a fogging sensor provided in the vehicle and indicating a physical index related to the degree of fogging on the window of the vehicle, or based on the operation of an on-board device capable of performing a fogging operation on the vehicle; When it is determined that there is a sign of fogging on the window, the level of driving control applicable to the vehicle is changed in accordance with the level of driving control currently being applied to the vehicle, so as to increase the degree of involvement of the driver of the vehicle in driving or suppress a decrease in the degree of involvement; When it is determined that there is a sign of fogging on the window, the driver is notified via a notification device provided in the vehicle that it is difficult to continue the automatic driving control of the vehicle. causing a processor mounted on the vehicle to execute the above steps; the fog sensor signal represents a measurement of humidity within the vehicle's cabin; Determining whether there is a sign of fogging on the window includes predicting a future time change in humidity inside the vehicle cabin based on the fogging sensor signal obtained in a recent predetermined period, calculating a predicted time until the humidity inside the vehicle cabin will become higher than a predetermined fogging determination threshold based on the predicted time change, and determining that there is a sign of fogging on the window if the predicted time change indicates that the humidity inside the vehicle cabin will become higher than the fogging determination threshold within a certain future period. Changing the level of driving control applicable to the vehicle includes changing the level of driving control to a level that requires the driver to monitor the surroundings of the vehicle after a predetermined grace period has elapsed since the notification, and setting the predetermined grace period to a shorter time as the predicted time is shorter. A computer program for vehicle control.

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