JP7708560B2 - Driving Support Devices - Google Patents

Description

This disclosure relates to a driving assistance device that assists in driving a vehicle to avoid collisions with surrounding obstacles.

In recent years, vehicles equipped with driving assistance functions and autonomous driving functions, such as Autonomous Emergency Brake (AEB) and Adaptive Cruise Control (ACC), have been put into practical use, mainly for the purpose of reducing traffic accidents and easing the driver's burden. For example, a device is known that detects obstacles around the vehicle based on information detected by various sensors, such as an exterior camera and LiDAR (Light Detection and Ranging), and assists the driving of the vehicle to avoid collisions between the vehicle and the obstacles. However, some traffic accidents are difficult to avoid unless preparatory actions, such as deceleration, are taken in anticipation of an accident, such as sudden jumps out of a blind spot.

In response to this, for example, Patent Document 1 discloses a technology that takes into consideration the occurrence of potential risks on the planned travel route of the vehicle that cannot be detected by the vehicle itself, such as a person suddenly jumping out of a blind spot, and predictively avoids such potential risks. Specifically, Patent Document 1 discloses a driving assistance device that starts automatic deceleration control when a braking or steering operation by the driver is detected after detecting a blind spot area seen from the vehicle in the vehicle's direction of travel, or when a predetermined time has passed. Patent Document 1 also describes that when a blind spot area is detected, the driver is notified of the risk of a pedestrian or cyclist jumping out of the blind spot area.

JP 2017-206039 A

However, since the blind spot area seen from the vehicle decreases as the vehicle travels, it is considered that when the area of the blind spot area becomes equal to or smaller than a predetermined area, there is no potential risk, or the content of the potential risk is limited. For example, as the blind spot area decreases, the types of objects that may exist in the blind spot area may be limited to smaller ones, or the speed at which the vehicle jumps out onto the trajectory may be limited according to the moving speed of objects that may exist in the decreasing blind spot area. In Patent Document 1, such changes in the blind spot area are not taken into consideration, so even when there is no potential risk or the content of the potential risk may be limited, the vehicle is controlled based on the initially calculated potential risk. Therefore, even in a situation where it is clear that there is no potential risk in the blind spot area, there is a risk that it will not be possible to transition to control after the potential risk no longer exists, such as acceleration control, until it is determined by a sensor or the like that there is no object in the blind spot area.

This disclosure has been made in consideration of the above problems, and the purpose of this disclosure is to provide a driving assistance device that can accurately estimate the risk of a collision with an object that may be present in a blind spot, based on changes over time in the detected blind spot.

In order to solve the above problem, according to one aspect of the present disclosure, there is provided a driving assistance device that assists driving of the vehicle based on risks present around the vehicle, the driving assistance device including a blind spot area calculation unit that identifies a blind spot area at a predetermined time and calculates a change over time in the blind spot area as the vehicle travels, and a risk estimation unit that hypothesizes an object that may be present in the blind spot area identified at the predetermined time and estimates a potential risk of a collision between the vehicle and an object that may be present in the blind spot area based on the change over time in the blind spot area identified at the predetermined time and the assumed behavior of the hypothesized object within the blind spot area.

As described above, according to the present disclosure, it is possible to accurately estimate the risk of collision with an object that may be present in a blind spot, based on the change in the detected blind spot over time.

1 is a schematic diagram illustrating a configuration example of a vehicle equipped with a driving assistance device according to an embodiment of the present disclosure. 2 is a block diagram showing a configuration example of a driving assistance device according to the embodiment; FIG. 4 is a flowchart showing a main routine of a control process performed by the driving assistance device according to the embodiment. 5 is a flowchart illustrating an example of an accumulated blind spot area calculation process performed by the driving assistance device according to the embodiment. 5 is a flowchart showing an example of a potential risk calculation process performed by the driving assistance device according to the embodiment. 1 is an explanatory diagram showing a change (decrease) in the cumulative blind spot area in a first application example and a pedestrian that may be present in the blind spot area; 1 is an explanatory diagram showing a change (decrease) in the cumulative blind spot area in a first application example and a bicycle that may be present in the blind spot area. FIG. 11 is an explanatory diagram showing a change (reduction) in the cumulative blind spot area taking into account the height direction of an obstruction (parked vehicle 2) in the first application example. FIG. FIG. 11 is an explanatory diagram showing another vehicle that may be present in a blind spot area of a preceding vehicle in a second application example.

Preferred embodiments of the present disclosure will be described in detail below with reference to the accompanying drawings. Note that in this specification and the drawings, components having substantially the same functional configurations are designated by the same reference numerals to avoid redundant description.

<1. Overall configuration of the vehicle>
First, an example of the overall configuration of a vehicle equipped with a driving assistance device according to an embodiment of the present disclosure will be described.

FIG. 1 is a schematic diagram showing an example of the configuration of a vehicle 1 equipped with a driving assistance device 50.
1 is configured as a four-wheel drive vehicle in which a driving torque output from a driving force source 9 that generates a driving torque for the vehicle is transmitted to a left front wheel 3LF, a right front wheel 3RF, a left rear wheel 3LR, and a right rear wheel 3RR (hereinafter collectively referred to as "wheels 3" unless a distinction is required). The driving force source 9 may be an internal combustion engine such as a gasoline engine or a diesel engine, a driving motor, or may include both an internal combustion engine and a driving motor.

The vehicle 1 may be an electric vehicle equipped with two drive motors, for example a front-wheel drive motor and a rear-wheel drive motor, or an electric vehicle equipped with drive motors corresponding to each wheel 3. In addition, if the vehicle 1 is an electric vehicle or a hybrid electric vehicle, the vehicle 1 is equipped with a secondary battery that stores the power supplied to the drive motors, and a generator such as a motor or fuel cell that generates power to charge the battery.

The vehicle 1 is equipped with a driving force source 9, an electric steering device 15, and brake devices 17LF, 17RF, 17LR, 17RR (hereinafter collectively referred to as "brake devices 17" unless a distinction is required) as devices used to control the operation of the vehicle 1. The driving force source 9 outputs a driving torque that is transmitted to the front drive shaft 5F and the rear drive shaft 5R via a transmission, a front wheel differential mechanism 7F, and a rear wheel differential mechanism 7R (not shown). The operation of the driving force source 9 and the transmission is controlled by a vehicle control unit 41 that includes one or more electronic control units (ECUs: Electronic Control Units).

The front-wheel drive shaft 5F is provided with an electric steering device 15. The electric steering device 15 includes an electric motor and a gear mechanism (not shown), and is controlled by the vehicle control unit 41 to adjust the steering angle of the left front wheel 3LF and the right front wheel 3RF. During manual driving, the vehicle control unit 41 controls the electric steering device 15 based on the steering angle of the steering wheel 13 by the driver. During automatic driving, the vehicle control unit 41 also controls the electric steering device 15 based on the set driving trajectory.

Brake devices 17LF, 17RF, 17LR, and 17RR apply braking forces to front, rear, left, and right drive wheels 3LF, 3RF, 3LR, and 3RR, respectively. Brake devices 17 are configured, for example, as hydraulic brake devices, and the hydraulic pressure supplied to each brake device 17 is controlled by vehicle control unit 41 to generate a predetermined braking force. When vehicle 1 is an electric vehicle or hybrid electric vehicle, brake devices 17 are used in conjunction with regenerative braking using a drive motor.

The vehicle control unit 41 includes one or more electronic control devices that control the drive of the driving force source 9 that outputs the driving torque of the vehicle 1, the electric steering device 15 that controls the steering angle of the steering wheel or steered wheels, and the brake device 17 that controls the braking force of the vehicle 1. The vehicle control unit 41 may also have a function of controlling the drive of a transmission that changes the speed of the output output from the driving force source 9 and transmits it to the wheels 3. The vehicle control unit 41 is configured to be able to acquire information transmitted from the driving assistance device 50, and is configured to be able to execute automatic driving control of the vehicle 1.

The vehicle 1 also includes forward-facing cameras 31LF, 31RF, a rearward-facing camera 31R, a vehicle state sensor 35, a GPS (Global Positioning System) sensor 37, and an HMI (Human Machine Interface) 43. Note that in this embodiment, the rearward-facing camera 31R may be omitted.

The front photographing cameras 31LF, 31RF and the rear photographing camera 31R constitute an ambient environment sensor for acquiring information on the ambient environment of the vehicle 1. The front photographing cameras 31LF, 31RF and the rear photographing camera 31R photograph the front or rear of the vehicle 1 and generate image data. The front photographing cameras 31LF, 31RF and the rear photographing camera 31R are equipped with imaging elements such as CCD (Charged-Coupled Devices) or CMOS (Complementary Metal-Oxide-Semiconductor), and transmit the generated image data to the driving assistance device 50. In the vehicle 1 shown in FIG. 1, the front photographing cameras 31LF, 31RF are configured as a stereo camera including a pair of left and right cameras, and the rear photographing camera 31R is configured as a so-called monocular camera, but each may be either a stereo camera or a monocular camera.

In addition to the front imaging cameras 31LF, 31RF and rear imaging camera 31R, the vehicle 1 may also be equipped with cameras mounted on the side mirrors 11L, 11R, for example, to capture images of the left rear or right rear. In addition, the vehicle 1 may also be equipped with one or more sensors as surrounding environment sensors for acquiring information about the surrounding environment, such as LiDAR (Light Detection And Ranging), a radar sensor such as a millimeter wave radar, or an ultrasonic sensor.

The vehicle state sensor 35 is composed of at least one sensor that detects the operation state and behavior of the vehicle 1. The vehicle state sensor 35 includes at least one of a steering angle sensor, an accelerator position sensor, a brake stroke sensor, a brake pressure sensor, or an engine speed sensor, and detects the operation state of the vehicle 1, such as the steering angle of the steering wheel or steering wheels, the accelerator opening, the amount of brake operation, or the engine speed. The vehicle state sensor 35 also includes at least one of a vehicle speed sensor, an acceleration sensor, or an angular velocity sensor, and detects the behavior of the vehicle, such as the vehicle speed, longitudinal acceleration, lateral acceleration, and yaw rate. The vehicle state sensor 35 transmits a sensor signal including the detected information to the driving assistance device 50.

The GPS sensor 37 receives satellite signals from GPS satellites. The GPS sensor 37 transmits the position information on the map data of the vehicle 1 contained in the received satellite signals to the driving assistance device 50. Note that instead of the GPS sensor 37, an antenna that receives satellite signals from other satellite systems that identify the position of the vehicle 1 may be provided.

The HMI 43 is driven by the driving assistance device 50 and presents various information to the driver by means of image display, audio output, and the like. The HMI 43 includes, for example, a display device provided in the instrument panel and a speaker provided in the vehicle. The display device may be a display device of a navigation system. The HMI 43 may also include a HUD (head-up display) that displays information on the windshield, superimposed on the scenery around the vehicle 1.

<2. Driving support device>
Next, the driving assistance device 50 according to this embodiment will be described in detail.

(2-1. Configuration example)
FIG. 2 is a block diagram showing an example of the configuration of the driving support device 50 according to this embodiment.
The driving assistance device 50 is connected to an ambient environment sensor 31, a vehicle state sensor 35, and a GPS sensor 37 directly or via a communication means such as a Controller Area Network (CAN) or a Local Inter Net (LIN). A vehicle control unit 41 and an HMI 43 are also connected to the driving assistance device 50. Note that the driving assistance device 50 is not limited to an electronic control device mounted on the vehicle 1, and may be a terminal device such as a smartphone or a wearable device.

The driving assistance device 50 includes a control unit 51, a memory unit 53, and an accumulated blind spot area database 55. The control unit 51 includes one or more processors such as a CPU (Central Processing Unit) and various peripheral components. A part or all of the control unit 51 may be configured with updatable firmware or the like, or may be a program module or the like that is executed by commands from the CPU or the like.

The memory unit 53 is composed of a memory element such as a RAM or a ROM. However, the type and number of the memory unit 53 are not particularly limited. The memory unit 53 stores information such as computer programs executed by the control unit 51, various parameters used in the calculation process, detection data, and calculation results. The cumulative blind spot database 55 is composed of a memory element such as a RAM or a ROM, or a storage medium such as an HDD, CD, DVD, SSD, USB flash, or storage device, and is a database that stores information on the cumulative blind spot calculated by the control unit 51.

(2-2. Functional Configuration)
Next, the functional configuration of the control unit 51 of the driving support device 50 will be described. The control unit 51 includes a surrounding environment detection unit 61, a blind spot area calculation unit 63, a risk estimation unit 65, a driving condition setting unit 67, and a notification control unit 69. Each of these units is a function realized by execution of a computer program by one or more processors such as a CPU. However, some or all of the surrounding environment detection unit 61, the blind spot area calculation unit 63, the risk estimation unit 65, the driving condition setting unit 67, and the notification control unit 69 may be configured by hardware.

(Ambient environment detection unit)
The surrounding environment detection unit 61 detects the surrounding environment of the host vehicle 1 based on the detection data transmitted from the surrounding environment sensor 31. Specifically, the surrounding environment detection unit 61 detects surrounding vehicles, people, bicycles, and other obstacles present around the host vehicle 1 using an object detection technique by performing image processing on the image data transmitted from the front-facing cameras 31LF and 31RF. In addition, the surrounding environment detection unit 61 calculates the positions of the surrounding vehicles, people, etc. as viewed from the host vehicle 1, the distances from the host vehicle 1 to the surrounding vehicles, people, etc., and the relative speeds of the surrounding vehicles, people, etc. with respect to the host vehicle 1.

(Blind spot area calculation unit)
The blind spot area calculation unit 63 identifies a blind spot area at a predetermined time and calculates the change over time of the blind spot area accompanying the movement of the host vehicle 1. The blind spot area as seen from the host vehicle 1 changes as the host vehicle 1 moves. In other words, if there is a blind spot area as seen from the host vehicle 1 at a certain time, a part of the blind spot area gradually comes into the field of view as the host vehicle 1 moves, so the area of the initially identified blind spot area gradually decreases as the host vehicle 1 moves. When an obstruction is detected in front of the host vehicle 1, the blind spot area calculation unit 63 identifies a blind spot area caused by the obstruction, and calculates an area (accumulated blind spot area) that continues to be maintained as a blind spot area, excluding an area (blind spot elimination area) that comes into the field of view as time passes.

For example, the blind spot area calculation unit 63 detects an obstruction based on the detection result by the surrounding environment detection unit 61. Typical examples of obstructions include parked vehicles, side walls, hedges, and other structures, but are not limited to these obstructions. In addition, the blind spot area calculation unit 63 may detect an obstruction or blind spot area using information on the position of the host vehicle 1 on the map data acquired via the GPS sensor 37 and road information ahead in the traveling direction.

The blind spot area calculation unit 63 may calculate the time change of a two-dimensional overhead blind spot area as seen from above the host vehicle 1 or an obstruction, or may calculate the time change of a two-dimensional blind spot area as seen from the host vehicle 1. The two-dimensional overhead blind spot area as seen from above the host vehicle 1 or an obstruction is defined in the lateral and depth directions as seen from the host vehicle 1, and the two-dimensional blind spot area as seen from the host vehicle 1 is defined in the lateral and height directions as seen from the host vehicle 1. In this embodiment, the blind spot area calculation unit 63 calculates the cumulative blind spot area defined in the lateral and depth directions as seen from the host vehicle 1, and the cumulative blind spot area defined in the lateral and height directions as seen from the host vehicle 1.

The calculated cumulative blind spot area is stored in the blind spot area database 55 until the vehicle 1 passes by the obstruction. This makes it possible to track changes in the cumulative blind spot area over time.

(Risk Estimation Department)
The risk estimation unit 65 assumes an object (hereinafter also referred to as a "potential risk object") that may be present in the blind spot area identified at a predetermined time, and estimates a potential risk of a collision between the vehicle 1 and the potential risk object that may be present in the blind spot area based on the change over time of the blind spot area and the assumed operation of the assumed potential risk object in the blind spot area. The assumed potential risk object is an object that is not detected by the surrounding environment sensor 31 of the vehicle 1, and the risk estimation unit 65 does not need to assume an object that, even if a part of it is present in the blind spot area, the other part of it appears within the detection range of the surrounding environment sensor 31. In addition, the assumed potential risk object is an object that may enter from the blind spot area in the traveling direction of the vehicle 1, and does not need to assume a stationary object.

Potential risk objects that may exist in the blind spot area or cumulative blind spot area identified at a given time can be assumed according to the size of the blind spot area or cumulative blind spot area. For example, if the size of the two-dimensional overhead blind spot area is large, there is a possibility that objects such as pedestrians, bicycles, and automobiles may exist in the blind spot area. For example, if the blind spot area or cumulative blind spot area is 5 m in the horizontal direction and 10 m in the depth direction as viewed from the vehicle 1, the types of potential risk objects may be pedestrians, bicycles, motorcycles, tricycles, automobiles, etc. On the other hand, if the size or width of the two-dimensional overhead blind spot area or cumulative blind spot area is small, there is a possibility that a pedestrian may exist in the blind spot area or cumulative blind spot area, but it is unlikely that a bicycle or motorcycle, etc. exists. Also, if the size or width of the two-dimensional overhead blind spot area or cumulative blind spot area is small, there is a possibility that a bicycle or motorcycle, etc. exists only in a specified direction.

In addition, when the height of the blind spot area or the accumulated blind spot area is high, there is a possibility that objects such as pedestrians, including adults and children, bicycles, motorcycles, tricycles, etc., are present in the blind spot area or the accumulated blind spot area. On the other hand, when the height of the blind spot area or the accumulated blind spot area is low, there is a possibility that children or tricycles are present in the blind spot area or the accumulated blind spot area, but there is a low possibility that adults, bicycles, motorcycles, etc. are present. Therefore, when an obstruction is detected in front of the vehicle 1 and a blind spot area is identified, the risk estimation unit 65 assumes the presence, position, and orientation of a potential risk object that may be present in the blind spot area based on the area and shape of the blind spot area defined in the horizontal and depth directions as seen from the vehicle 1, and the area and shape of the blind spot area defined in the horizontal and height directions as seen from the vehicle 1.

The risk estimation unit 65 also sets the potential risk object that may be present in the cumulative blind spot area and the intrusion speed of the potential risk object ahead of the host vehicle 1 based on the change in the area of the cumulative blind spot area as the host vehicle 1 travels. Specifically, as the area of the cumulative blind spot area decreases, the types of potential risk objects that may be present in the blind spot area become more limited. Furthermore, assuming that there is a potential risk object that is still not detected by the surrounding environment sensor 31 of the host vehicle even as the area of the cumulative blind spot area decreases as the host vehicle 1 travels, the set speed range of the potential risk object and the set trajectory of the potential risk object within the cumulative blind spot area become more limited. The set speed range of the potential risk object can be replaced with the intrusion speed of the potential risk object ahead of the host vehicle 1, and the set trajectory of the potential risk object is used to determine the intrusion position of the potential risk object ahead of the host vehicle 1.

The risk estimation unit 65 estimates the potential risk based on the potential risk object that may exist in the blind spot area or the accumulated blind spot area, the set speed range of the potential risk object, and the set trajectory of the potential risk object. The lower the possibility that the potential risk object will invade the area in front of the vehicle 1 from the blind spot area, the lower the estimated potential risk. Specifically, as the accumulated blind spot area decreases with the movement of the vehicle 1, the potential risk becomes relatively lower. For example, if the accumulated blind spot area is 2 m laterally and 1 m deep from the vehicle 1, the types of potential risk objects that may exist are limited to bicycles and pedestrians. Furthermore, since the potential risk object continues to remain in the accumulated blind spot area, it is in an almost stopped state, and the expected intrusion speed becomes slow.

Therefore, the area where the assumed potential risk object may intrude in front of the host vehicle 1, that is, the variation in the protruding distance and intrusion position, is small, and even if the potential risk object intrudes in front of the host vehicle 1, the area where it may collide with the host vehicle 1 is small, so the potential risk is estimated to be relatively low. On the other hand, if the area where the assumed potential risk object may intrude in front of the host vehicle 1 is large, and the area where the potential risk object may collide with the host vehicle 1 if it intrudes in front of the host vehicle 1 is large, the potential risk is estimated to be relatively high. For example, the risk estimation unit 65 may set the potential risk in multiple stages depending on the area of the area where the potential risk object may collide with the host vehicle 1 if it intrudes in front of the host vehicle 1.

After an obstruction is detected at a predetermined time and a blind spot area is detected, the risk estimation unit 65 repeatedly hypothesizes a potential risk object that may be present in the blind spot area and estimates the potential risk of the hypothesized potential risk object colliding with the vehicle 1 until the vehicle 1 passes beside the obstruction. The risk estimation unit 65 estimates the potential risk for each of the multiple potential risk objects that may be hypothesized.

(Operation condition setting section)
The driving condition setting unit 67 basically sets the driving conditions of the host vehicle 1 so as to avoid a collision with an obstacle present ahead in the traveling direction of the host vehicle 1. For example, the driving condition setting unit 67 sets a travel trajectory that can avoid a collision between the host vehicle and an obstacle during the autonomous driving of the host vehicle 1, and sets a target steering angle for driving the host vehicle 1 along the travel trajectory. For example, the driving condition setting unit 67 sets the travel trajectory of the host vehicle 1 using a risk potential that is an index indicating the possibility that the host vehicle 1 will collide with a pedestrian, a surrounding vehicle, or other obstacle. In this case, the risk potential is set so that the closer the distance to the obstacle is, the higher the collision risk is, and the driving condition setting unit 67 sets the travel trajectory so that the host vehicle 1 travels on a trajectory where the collision risk is smaller. In addition, when the risk potential is set so that the collision risk is smaller as the vehicle speed is lower, the driving condition setting unit 67 may reduce the collision risk by setting the travel trajectory and the vehicle speed.

In addition, in this embodiment, the driving condition setting unit 67 sets driving conditions so that the host vehicle 1 travels on a trajectory that reduces the above-mentioned collision risk and the potential risk until the host vehicle 1 passes by the obstacle that creates the blind spot area. Specifically, when the driving condition setting unit 67 determines that the potential risk object may collide with the host vehicle 1 based on the potential risk estimated by the risk estimation unit 65, it sets a driving trajectory so that the distance between the host vehicle 1 and the obstacle increases. Furthermore, when the potential risk cannot be sufficiently reduced by changing the driving trajectory alone, the driving condition setting unit 67 may reduce the potential risk by decelerating the host vehicle 1 in addition to changing the driving trajectory or instead of changing the driving trajectory.

The driving condition setting unit 67 sets a target steering angle and a target acceleration/deceleration based on the set driving trajectory and vehicle speed, and transmits the target steering angle and target acceleration/deceleration information to the vehicle control unit 41. The vehicle control unit 41 controls the driving of the host vehicle 1 based on the acquired target steering angle and target acceleration/deceleration information. At this time, the driving condition setting unit 67 may set the target steering angle and the target acceleration/deceleration so as not to exceed a preset upper limit value of the steering angular speed or an upper limit value of the acceleration/deceleration. This controls the driving of the host vehicle 1 so that sudden steering or sudden deceleration does not occur, reducing discomfort felt by the occupants of the host vehicle 1.

In addition, if the potential risk no longer exists while the driving condition setting unit 67 is setting the driving conditions to reduce the potential risk, the driving condition setting unit 67 ends the process of setting the driving conditions to reduce the potential risk even before the host vehicle 1 passes by the obstacle that caused the blind spot. This allows the host vehicle 1 to transition to a driving mode for after passing by the obstacle before the surrounding environment sensor 31 of the host vehicle 1 detects that there is no object in the blind spot. This reduces the risk of the user feeling annoyed that the host vehicle 1 will not accelerate even though it is clear that there is no object in the blind spot that may cause a collision with the host vehicle 1.

(Notification control section)
The notification control unit 69 notifies the occupants of the vehicle 1 by controlling the driving of the HMI 43. In this embodiment, the notification control unit 69 notifies the occupants of the vehicle 1 of the presence of a potential risk of the vehicle 1 colliding with a potential risk object that may be present in the blind spot area. The notification control unit 69 notifies the occupants of the vehicle 1 of the presence of a potential risk by outputting a warning sound or voice, or by displaying an image or text. The content of the notification is not particularly limited, and may be a certain warning sound or voice, an image or text display, or the position or speed at which the potential risk object will enter the area ahead of the vehicle 1 from the blind spot area.

Furthermore, after the notification control unit 69 detects the presence of a potential risk and starts the notification process, if the potential risk no longer exists, it stops the notification process even before the vehicle 1 passes by the obstruction that created the blind spot. This stops unnecessary notifications when it is clear that there is no object in the blind spot that may cause a collision with the vehicle 1, reducing the risk of the user feeling annoyed.

3. Operation of the driving support device
Next, an example of the operation of the driving support device according to this embodiment will be described with reference to a flowchart.

3 to 5 are flowcharts showing an example of the operation of the driving support device 50.
First, when the system including the driving assistance device 50 is started (step S11), the surrounding environment detection unit 61 of the control unit 51 acquires detection data transmitted from the surrounding environment sensor 31, and detects the surrounding environment of the host vehicle 1 based on the detection data (step S13). In this embodiment, the surrounding environment detection unit 61 detects other vehicles, people, buildings, traffic signs, white lines, etc. that are present at least ahead of the host vehicle 1 in the traveling direction based on the detection data transmitted from the surrounding environment sensor 31.

Next, the blind spot calculation unit 63 of the control unit 51 determines whether or not there is an obstruction that may cause a blind spot as seen from the host vehicle 1 ahead in the traveling direction of the host vehicle 1 (step S15). For example, the blind spot calculation unit 63 calculates the size and position of each object detected by the surrounding environment detection unit 61 and the relative speed of each object with respect to the host vehicle 1, and determines whether or not there is an object that may cause a blind spot as seen from the host vehicle 1. For example, the blind spot calculation unit 63 determines that an object corresponds to an obstruction when the width, height, and depth of the object are each equal to or larger than a preset dimension, the object is within a preset distance from the planned trajectory of the host vehicle 1, and the relative speed is equal to or smaller than a preset speed threshold.

If it is not determined that there is an obstruction that may cause a blind spot (S15/No), the process returns to step S13, and the process of detecting the surrounding environment (step S13) and the process of determining whether or not there is an obstruction (step S15) are repeated. On the other hand, if it is determined that there is an obstruction that may cause a blind spot (S15/Yes), the blind spot area calculation unit 63 executes a process of calculating the cumulative blind spot area X (step S17).

FIG. 4 is a flowchart showing the accumulated blind spot area calculation process.
First, the blind spot calculation unit 63 acquires information on the size, position, and relative speed of the object determined to be an obstruction (step S41). Next, the blind spot calculation unit 63 calculates the current blind spot x(t) caused by the obstruction as seen from the vehicle 1 based on the size of the obstruction and the positional relationship between the obstruction and the vehicle 1 (step S43). For example, the blind spot calculation unit 63 identifies an area located behind the obstruction as seen from the vehicle 1 among areas surrounded by a group of straight lines passing through the installation positions of the front photographing cameras 31FL, 31RF provided on the vehicle 1 and a plurality of points on the contour of the obstruction as seen from the vehicle 1. The identified blind spot x(t) is obtained as an area in the lateral direction, height direction, and depth direction as seen from the vehicle 1. After the obstruction is detected, the blind spot calculation unit 63 repeats the calculation of the blind spot x(t) at appropriate processing intervals until the vehicle 1 passes by the obstruction or until it is determined that there is no potential risk.

Then, the blind spot calculation unit 63 compares the calculated current blind spot area x(t) with the accumulated blind spot area X(t-Δt) up to the previous time stored in the accumulated blind spot area database 55 (step S45). The blind spot calculation unit 63 identifies a blind spot elimination area y that does not overlap with the current blind spot area (t) from the accumulated blind spot area X(t-Δt) up to the previous time.

Next, the blind spot calculation unit 63 updates the cumulative blind spot area X(t) to calculate the current cumulative blind spot area X(t) (step S47). As a result, the blind spot elimination area y that entered the field of view of the vehicle 1 as the vehicle 1 traveled is removed from the blind spot area x(t) identified when the vehicle 1 detected an obstruction, and the cumulative blind spot area X(t) that continues to be maintained as a blind spot area is calculated.

Then, the blind spot calculation unit 63 stores the calculated cumulative blind spot area X(t) in the cumulative blind spot database 55 (step S49). This makes it possible to refer to the previous cumulative blind spot area X(t-Δt) when calculating the cumulative blind spot area X(t) from the next time onwards. Note that in the first blind spot calculation process after it is determined that there is an obstruction causing a blind spot area x, the calculated blind spot area x(t) is stored as the cumulative blind spot area X(t).

The blind spot calculation unit 63 repeatedly executes the cumulative blind spot calculation process at a predetermined processing interval until the vehicle 1 passes beside the obstruction or the potential risk no longer exists.

Returning to FIG. 3, after the blind spot area calculation unit 63 executes the process of calculating the cumulative blind spot area X(t) in step S17, the risk estimation unit 65 of the control unit 51 executes the process of calculating the potential risk of a collision between the host vehicle 1 and a potential risk object that may be present in the cumulative blind spot area X(t) (step S19).

FIG. 5 is a flowchart showing the potential risk calculation process.
First, the risk estimation unit 65 assumes a potential risk object that may exist in the cumulative blind spot area X(t) calculated in step S17 (step S51). Specifically, the risk estimation unit 65 assumes a potential risk object that may exist depending on the size of the cumulative blind spot area X(t). As described above, an object that may intrude in front of the vehicle 1 is assumed as a potential risk object. For example, the risk estimation unit 65 assumes the type, position, and orientation of a potential risk object that may exist in the cumulative blind spot area X(t) based on the area and shape of the cumulative blind spot area X(t) seen in a two-dimensional bird's-eye view, and the area and shape of the cumulative blind spot area X(t) including the element in the height direction of the obstruction seen from the vehicle 1.

The risk estimation unit 65 assumes multiple potential risk objects that may exist in the cumulative blind spot area X(t). In this case, the same type of object may be assumed to be in different positions, or different types of objects may be assumed to be in the same or different positions. In addition, to avoid assuming an object that is unlikely to collide with the host vehicle 1, a potential risk object may be assumed to be in the cumulative blind spot area X(t) within a preset distance range from an obstruction. In this case, the distance from the obstruction may be longer as the vehicle speed of the host vehicle 1 or the relative speed of the host vehicle 1 with respect to the obstruction is faster.

Next, the risk estimation unit 65 sets a trajectory in the cumulative blind spot area X(t) of a potential risk object that may exist in the cumulative blind spot area X(t) based on the change in the area and shape of the cumulative blind spot area X(t) accompanying the movement of the vehicle 1 (step S53). For example, the risk estimation unit 65 can set the trajectory of each potential risk object by connecting the positions of potential risk objects of the same type that may exist in the cumulative blind spot area X(t) calculated at each time while the area and shape of the cumulative blind spot area X(t) change. The trajectory to be set may be only a trajectory in a direction that allows the potential risk object to enter in front of the vehicle 1. In order to prevent an increase in the load of the calculation process, the trajectory to be set may be only a straight trajectory. The risk estimation unit 65 sets one or more trajectories for each of the assumed potential risk objects. The smaller the area or width of the cumulative blind spot area X(t), the shorter the length of the trajectory that can be set.

Next, the risk estimation unit 65 sets the speed of the potential risk object that may exist in the cumulative blind spot area X(t) based on the change in the area and shape of the cumulative blind spot area X(t) accompanying the movement of the vehicle 1 (step S55). For example, the risk estimation unit 65 sets the speed obtained by dividing the length of the trajectory set in step S53 by the time it takes for the potential risk object to move on the trajectory as the speed of the potential risk object. The time it takes for the potential risk object to move on the trajectory can be calculated as the sum of the processing intervals from the time when the potential risk object is assumed to be at the start point of the trajectory to the time when the potential risk object is assumed to be at the end point of the trajectory. In this embodiment, after it is determined that an obstruction exists and the blind spot area x is detected, no new potential risk object is assumed while the vehicle 1 is moving, and a potential risk object that may continue to exist in the cumulative blind spot area X(t) from the beginning when the blind spot area x was detected is assumed. For this reason, basically, the shorter the length of the trajectory set, the slower the set speed.

Next, the risk estimation unit 65 estimates the potential risk of the potential risk object colliding with the vehicle 1 based on the potential risk object that may exist in the cumulative blind spot area X(t), the set speed range of the potential risk object, and the set trajectory of the potential risk object (step S57). Basically, as the cumulative blind spot area X(t) decreases with the movement of the vehicle 1, the potential risk becomes relatively lower. For example, as the cumulative blind spot area X(t) decreases, the objects that may exist in the cumulative blind spot area X(t) are limited to relatively small objects. In addition, the speed of the potential risk object that is assumed to remain in the cumulative blind spot area X(t) whose area is decreasing becomes slower. Therefore, even if the potential risk object invades in front of the vehicle 1, the area where it may collide with the vehicle 1 is small, so the potential risk is estimated to be relatively low. On the other hand, if the area where the potential risk object may collide with the vehicle 1 when it invades in front of the vehicle 1 is large, the potential risk is estimated to be relatively high.

In this embodiment, the risk estimation unit 65 sets potential risks in multiple stages according to the area of the area where a potential risk object may collide with the host vehicle 1 when it enters in front of the host vehicle 1. For example, the risk estimation unit 65 sets the potential risk higher the larger the area of the area where a potential risk object may enter within the passing area (passing range) of the host vehicle 1, which is set based on the current vehicle speed, acceleration/deceleration, and steering angle of the host vehicle 1.

Returning to FIG. 3, after the potential risk is calculated in step S19, the driving condition setting unit 67 determines whether or not the potential risk object that may exist in the cumulative blind spot area X(t) is likely to collide with the vehicle 1 (step S21). For example, the driving condition setting unit 67 determines whether or not the potential risk object is likely to collide with the vehicle 1 based on the passing points in time series when the vehicle 1 is traveling along the current traveling trajectory and the intrusion position and time when the potential risk object is assumed to intrude into the traveling trajectory of the vehicle 1. Specifically, the driving condition setting unit 67 can determine that the potential risk object is likely to collide with the vehicle 1 if the distance between the passing point of the vehicle 1 and the intrusion position of the potential risk object is within a predetermined distance at any time. Note that instead of determining whether or not the potential risk object is likely to collide with the vehicle 1, it may be determined whether or not the potential risk estimated in step S19 is less than a predetermined risk value.

If it is determined that there is a possibility that the potential risk object will collide with the vehicle 1 (S21/Yes), the notification control unit 69 executes at least one of the following processes: notifying the occupants of the vehicle 1 of the existence of a potential risk of the vehicle 1 colliding with the potential risk object that may be present in the blind spot area (notification process), or the driving condition setting unit 67 executes a process to avoid a collision with the potential risk object (avoidance process) (step S23).

For example, the notification control unit 69 notifies the driver of the presence of a potential risk by outputting a warning sound or voice, or by displaying an image or text. The content of the notification is not particularly limited, and may output a certain warning sound or voice, or by displaying an image or text, or may notify the driver of the position or speed at which a potential risk object will enter the area ahead of the vehicle 1 from the blind spot area.

The driving condition setting unit 67 also avoids a collision with the potential risk object by setting a driving trajectory such that the distance between the vehicle 1 and the obstacle increases. The greater the distance between the vehicle 1 and the obstacle, the smaller the area of the area in which the potential risk object may collide with the vehicle 1 when it enters in front of the vehicle 1, and therefore the smaller the potential risk. In addition, when the driving condition setting unit 67 is unable to avoid a collision with the potential risk object by changing the driving trajectory alone, the driving condition setting unit 67 may avoid a collision with the potential risk object by decelerating the vehicle 1 in addition to changing the driving trajectory, or instead of changing the driving trajectory. The driving condition setting unit 67 sets a target steering angle and a target acceleration/deceleration based on the set driving trajectory and vehicle speed, and transmits information on the target steering angle and the target acceleration/deceleration to the vehicle control unit 41. The vehicle control unit 41 controls the driving of the vehicle 1 based on the acquired information on the target steering angle and the target acceleration/deceleration.

After the notification process or the avoidance process is performed in step S23, the blind spot area calculation unit 63 determines whether the host vehicle 1 has passed beside the obstacle that caused the blind spot area x (step S25). For example, based on the information on the surrounding environment detected by the surrounding environment detection unit 61, the blind spot area calculation unit 63 determines that the host vehicle 1 has passed beside an obstacle when an obstacle that was previously detected in front of the host vehicle 1 is no longer detected. The blind spot area calculation unit 63 may store the position of the detected obstacle on the map data, and determine that the host vehicle 1 has passed beside an obstacle when the host vehicle 1 passes that position.

If it is not determined that the host vehicle 1 has passed beside the obstacle (S25/No), the process returns to step S17 and repeats the processing of each step described above. On the other hand, if it is determined that the host vehicle 1 has passed beside the obstacle (S25/Yes), the driving condition setting unit 67 proceeds to processing after passing beside the obstacle (step S27). For example, the driving condition setting unit 67 starts processing to return the driving trajectory that has increased the distance between the host vehicle 1 and the obstacle to a reference position such as the center of the road, or to accelerate the host vehicle 1 to return it to the reference vehicle speed.

On the other hand, if it is not determined in step S21 that the potential risk object is likely to collide with the vehicle 1 (S21/No), the driving condition setting unit 67 proceeds to processing after passing the side of the obstruction regardless of whether the vehicle 1 has passed the side of the obstruction (step S27). This allows the vehicle 1 to quickly return to its original driving trajectory or vehicle speed if it is clear that no object is present in the blind spot area x even before passing the side of the obstruction, thereby reducing the annoyance felt by the occupants of the vehicle 1.

After moving to the process after passing by the obstacle in step S27, it is determined whether the system of the vehicle 1 including the driving assistance device 50 has stopped (step S29). If the system has not stopped (S29/No), the process returns to step S13 and repeats the process of each step described above. On the other hand, if the system has stopped (S29/Yes), the operation of the driving assistance device 50 is stopped.

In this way, the driving support device 50 according to this embodiment identifies the blind spot area x at a predetermined time when an obstacle that creates a blind spot area is detected ahead of the vehicle 1 in the traveling direction, and calculates the cumulative blind spot area X that indicates the time change of the blind spot area x accompanying the subsequent traveling of the vehicle 1. In addition, the driving support device 50 sets the type, position, trajectory, and speed of a potential risk object that may exist in the cumulative blind spot area X based on the change in the cumulative blind spot area X, and estimates the potential risk of the potential risk object colliding with the vehicle 1. This makes it possible to change the traveling trajectory or perform a deceleration operation according to the potential risk, rather than performing uniform avoidance control when a blind spot area is detected. In addition, when it is clear that no object exists in the blind spot area, even before the obstacle is no longer detected by the surrounding environment sensor 31 of the vehicle 1, the process is quickly shifted to the process after passing by the obstacle. Therefore, the annoyance felt by the occupants of the vehicle 1 can be reduced.

＜4. Application Examples＞
The driving support device 50 according to this embodiment has been described above. Below, some examples of driving scenes to which the driving support device 50 according to this embodiment is applied will be described.

(4-1. First Application Example)
6 to 8 are diagrams for explaining the first application example, and are explanatory diagrams showing a driving scene in which the host vehicle 1 passes beside a parked vehicle 2. In FIG.

FIG. 6 shows a two-dimensional overhead view of a blind spot area.
At time t, the blind spot area calculation unit 63 detects a parked vehicle 2 as an obstruction in front of the host vehicle 1, and identifies a blind spot area x(t) seen from the host vehicle 1 and caused by the parked vehicle 2. The blind spot area calculation unit 63 regards the blind spot area x(t) identified when the parked vehicle 2 is detected as a cumulative blind spot area X(t).

As the vehicle 1 travels, the blind spot areas x(t+Δt) and x(t+2Δt) at times t+Δt and t+2Δt change. Therefore, at times t+Δt and t+2Δt, a portion of the blind spot area x(t) detected at time t gradually enters the field of view of the vehicle 1, and the blind spot elimination area y gradually expands over time. At times t+Δt and t+2Δt, the blind spot calculation unit 63 determines the blind spot areas that overlap with the blind spot areas x(t) and x(t+Δt) detected up to the previous times t and t+Δt as the cumulative blind spot areas X(t+Δt) and X(t+2Δt). In other words, the cumulative blind spot area X(t+Δt) at time t+Δt is the area where the cumulative blind spot area X(t) at time t and the blind spot area x(t+Δt) at time t+Δt overlap, and the cumulative blind spot area X(t+2Δt) at time t+2Δt is the area where the cumulative blind spot area X(t+Δt) at time t+Δt and the blind spot area x(t+2Δt) at time t+2Δt overlap. It can also be said that the cumulative blind spot area X(t+2Δt) at time t+2Δt is the area where the blind spot area x(t) at time t, the blind spot area x(t+Δt) at time t+Δt, and the blind spot area x(t+2Δt) at time t+2Δt overlap.

The risk estimation unit 65 assumes a potential risk object that may be present in the cumulative blind spot area X(t) at time t when the obstruction is detected. In the example shown in FIG. 6, a pedestrian 3 is assumed to be present in each of two locations in the cumulative blind spot area X(t) at time t, but other potential risk objects such as bicycles and automobiles can be assumed based on the area of the cumulative blind spot area X(t). In addition, the risk estimation unit 65 assumes a potential risk object that may be present in the cumulative blind spot areas X(t+Δt) and X(t+2Δt) at each time t+Δt and t+2Δt. If it is assumed to be a pedestrian 3 that has not been detected by the vehicle 1 at the previous times t and t+Δt, the potential risk objects that may be assumed in the cumulative blind spot areas X(t+Δt) and X(t+2Δt) are limited to pedestrians and bicycles.

The risk estimation unit 65 also sets the assumed speed and trajectory of the potential risk object in the cumulative blind spot area X(t), X(t+Δt), X(t+2Δt) at each time t, t+Δt, t+2Δt. The cumulative blind spot area X(t) at time t is the blind spot area X(t) that has been detected for the first time, and since it is not possible to predict the movement of the potential risk object prior to that time, various variations in the speed and trajectory of the potential risk object in the cumulative blind spot area X(t) at time t can be assumed. On the other hand, if it is assumed that the cumulative blind spot areas X(t+Δt), X(t+2Δt) at times t+Δt, t+2Δt are potential risk objects that have not been detected by the vehicle 1 even at the times t, t+Δt up to that point, the speed and trajectory of the potential risk object in the cumulative blind spot area X(t+Δt), X(t+2Δt) are limited.

Figure 7 shows an example in which a bicycle 4 is assumed as a potential risk object. The bicycle 4 can be assumed to move at a relatively faster speed than a pedestrian. In addition, since the length of the bicycle 4 is greater than the width of a pedestrian, the position and direction of the bicycle 4 that can be assumed to move toward the traveling direction of the vehicle 1 are more limited than those of a pedestrian. For example, the bicycle 4 can be assumed in the area of the cumulative blind spot area X(t+2Δt) at time t+2Δt in Figure 7, but the bicycle 4 cannot be assumed in the area of the cumulative blind spot area X(t+2Δt) at time t+2Δt in Figure 6. Therefore, the area of the area in front of the vehicle 1 where the bicycle 4 can enter becomes relatively small. In addition, although the bicycle 4 can be assumed in the area of the cumulative blind spot area X(t+2Δt) at time t+2Δt in Figure 7, it is clear that the bicycle 4 has continued to remain in the cumulative blind spot area X(t+2Δt) since time t, so it is estimated that the bicycle 4 is almost stopped and that even if it enters the area in front of the vehicle 1, its intrusion speed is slow. Therefore, at time t+2Δt, the potential risk of the vehicle 1 colliding with the bicycle 4 is estimated to be low.

In this way, the driving assistance device 50 according to this embodiment can accurately estimate the potential risk of the host vehicle 1 colliding with a potential risk object, assuming the presence or absence of a potential risk object that may be present in the cumulative blind spot area X(t) and the intrusion position and intrusion speed ahead of the host vehicle 1, based on the change in the cumulative blind spot area X(t) indicating the time change of the blind spot area x(t) identified at a specified time. This makes it possible to appropriately change the travel trajectory or decelerate the vehicle 1 according to the potential risk. In addition, the risk estimation unit 65 determines that the potential risk has disappeared before the host vehicle 1 passes beside the parked vehicle 2, and the timing for accelerating the host vehicle 1 or returning the travel trajectory to the original can be brought forward.

Furthermore, FIG. 8 shows the change in the cumulative blind spot area X taking into account the height direction of the obstruction (parked vehicle 2). When comparing the blind spot areas x(t), x(t+Δt), and x(t+Δ2t) in the height direction of the parked vehicle 2 over time, the cumulative blind spot areas X(t+Δt) and X(t+2Δt) are smaller than when comparing the overhead two-dimensional blind spot areas x(t), x(t+Δt), and x(t+Δ2t) shown in FIG. 6 and FIG. 7 over time. Specifically, when the height direction of the parked vehicle 2 is taken into account, the space above the bonnet of the parked vehicle 2 gradually comes into view as the host vehicle 1 moves forward. The part of the bonnet where this upper space becomes the blind spot elimination area y cannot be assumed to be a potential risk object because its size in the height direction is small. Therefore, among the cumulative blind spot areas X(t+Δt) and X(t+2Δt), the area in which a potential risk object can be assumed is more limited than the cumulative blind spot areas X(t+Δt) and X(t+2Δt) shown only in a two-dimensional bird's-eye view as shown in Figures 6 and 7. In other words, the timing at which the risk estimation unit 65 determines that the potential risk has disappeared can be made earlier, and the timing at which the vehicle 1 accelerates or returns to its original traveling trajectory can be made earlier.

(4-2. Second application example)
FIG. 9 is a diagram for explaining a second application example, and is an explanatory diagram showing a driving scene in which, when vehicle 1 is traveling in the left lane of a three-lane road, the speed of leading vehicle 5 traveling in the center lane is slower than the speed of vehicle 1, and vehicle 1 overtakes leading vehicle 5 to get in front of vehicle 5.

FIG. 9 shows a two-dimensional overhead view of a blind spot area.
At time t, the blind spot calculation unit 63 detects the preceding vehicle 5 as an obstruction in the center lane in front of the vehicle 1, and identifies the blind spot x(t) seen from the vehicle 1 caused by the preceding vehicle 5. The blind spot calculation unit 63 regards the blind spot x(t) identified when the preceding vehicle 5 is recognized as a vehicle to be overtaken as the cumulative blind spot X(t). In addition, as the vehicle 1 advances, the blind spot x(t+Δt) and x(t+2Δt) at the times t+Δt and t+2Δt change. Therefore, at the times t+Δt and t+2Δt, a part of the blind spot x(t) detected at time t gradually enters the field of view seen from the vehicle 1, and the blind spot elimination area y gradually expands as time passes. The blind spot calculation unit 63 calculates the cumulative blind spot areas X(t+Δt) and X(t+2Δt) at times t+Δt and t+2Δt, respectively.

The risk estimation unit 65 assumes a potential risk object that may exist in the cumulative blind spot area X(t) at the time t when the obstruction is detected. In the example shown in FIG. 9, the risk estimation unit 65 assumes a potential risk object that exists in the right lane behind the center lane as seen from the vehicle 1, so it does not assume a pedestrian or bicycle, but assumes another vehicle 6 traveling in the right lane.

The risk estimation unit 65 also sets the speed and trajectory of the assumed potential risk object in the cumulative blind spot areas X(t), X(t+Δt), and X(t+2Δt) at times t, t+Δt, and t+2Δt. In the example shown in FIG. 9, at times t+Δt and t+2Δt, the blind spot elimination area y gradually expands in the forward part of the blind spot area x(t) identified at time t, but the other vehicle 6 is not apparent in the blind spot elimination area y. For this reason, it is clear that the vehicle speed of the assumed other vehicle 6 is relatively slow compared to the vehicle speeds of the host vehicle 1 and the preceding vehicle 5, and therefore it is determined that the possibility of the other vehicle 6 changing lanes ahead of the preceding vehicle 5 is low.

In the example shown in FIG. 9, if the presence or absence of a blind spot is simply considered, a notification indicating that changing lanes is dangerous is issued until the surrounding environment sensor 31 of the host vehicle 1 confirms that there is no obstruction that would cause a blind spot, that is, until it is confirmed that the vehicle ahead 5 has completed overtaking. On the other hand, the driving support device 50 according to this embodiment can accurately estimate the potential risk of the host vehicle 1 colliding with another vehicle 6 that is changing lanes (invading) from the right lane to the center lane in front of the vehicle ahead 5, based on the change in the cumulative blind spot area X(t) that indicates the time change in the blind spot area x(t) accompanying the progression of the vehicle 1. As a result, the risk estimation unit 65 determines that the potential risk has disappeared before the vehicle 1 overtakes the vehicle ahead 5, and the timing for completing the overtaking of the vehicle ahead 5 by the vehicle 1 or for stopping the notification that changing lanes is dangerous can be advanced.

<5. Summary>
As described above, the driving support device 50 according to this embodiment identifies the blind spot area x(t) at a predetermined time t, and calculates the cumulative blind spot areas X(t), X(t+Δt), and X(t+2Δt) indicating the time change of the blind spot area x(t) accompanying the travel of the vehicle 1 at each of the times t, t+Δt, and t+2Δt. In addition, the driving support device 50 assumes a potential risk object that may exist in the calculated cumulative blind spot areas X(t), X(t+Δt), and X(t+2Δt), and estimates a potential risk of a collision between the vehicle 1 and the potential risk object based on the cumulative blind spot areas X(t), X(t+Δt), and X(t+2Δt) and the assumed operation of the assumed potential risk object in the cumulative blind spot areas X(t), X(t+Δt), and X(t+2Δt). This makes it possible to accurately estimate the potential risk of a collision with a potential risk object that may be present in the blind spot area, rather than simply determining whether or not a blind spot area exists when viewed from the vehicle 1.

Therefore, when the driving assistance device 50 notifies the occupants of the vehicle 1 of the presence of a potential risk, the notification can be stopped when the potential risk no longer exists, even before the vehicle 1 passes beside the obstruction (parked vehicle 2 or leading vehicle 5) that was creating the blind spot. This stops unnecessary notifications when it is clear that there is no object in the blind spot that may cause a collision with the vehicle 1, reducing the risk of the user feeling annoyed.

In addition, when the driving assistance device 50 controls the autonomous driving of the vehicle 1, the setting of driving conditions that reduce the potential risk can be terminated when the potential risk no longer exists, even before the vehicle 1 passes beside the obstacle (parked vehicle 2 or leading vehicle 5) that was creating the blind spot. This can reduce the risk of the user feeling annoyed that the vehicle 1 will not accelerate even though it is clear that there is no object in the blind spot that may cause a collision with the vehicle 1.

In addition, the driving assistance device 50 according to this embodiment sets the speed and trajectory of the potential risk object within the cumulative blind spot area, or the intrusion speed of the potential risk object ahead of the vehicle 1, based on the change in the cumulative blind spot area, which indicates the change in the area of the blind spot area, and estimates the potential risk. This makes it possible to accurately estimate the potential risk of a collision between the vehicle 1 and the potential risk object according to the area of the area in which the hypothesized potential risk object may intrude into the passing area of the vehicle 1, thereby improving the accuracy of driving assistance control.

In addition, the driving assistance device 50 according to this embodiment estimates potential risks by considering not only the two-dimensional overhead blind spot area defined in the lateral and depth directions as seen from the vehicle 1, but also the blind spot area in the height direction of the obstruction. Therefore, it is possible to accurately hypothesize objects that may exist in the blind spot area, and to accurately estimate the potential risk of a collision between the vehicle 1 and a potential risk object, thereby improving the accuracy of driving assistance control.

Although the preferred embodiment of the present disclosure has been described in detail above with reference to the attached drawings, the present disclosure is not limited to such examples. It is clear that a person with ordinary knowledge in the technical field to which the present disclosure pertains can conceive of various modified or revised examples within the scope of the technical ideas described in the claims, and it is understood that these also naturally fall within the technical scope of the present disclosure.

For example, in the above embodiment, the larger the area of the passing area (passing range) of the vehicle 1 into which the potential risk object may enter, the higher the potential risk is set, but the present disclosure is not limited to such an example. For example, the potential risk may be set according to the type and number of potential risk objects that may be assumed to be in the cumulative blind spot area and the speed of intrusion forward of the vehicle 1.

In addition, a computer program applicable to a driving assistance device that assists the driving of a vehicle based on risks present around the vehicle, the computer program causing a processor to execute processes including identifying a blind spot area at a predetermined time and calculating the change over time of the blind spot area as the vehicle moves, hypothesizing an object that may be present in the blind spot area identified at the predetermined time, and estimating the potential risk of a collision between the vehicle and an object that may be present in the blind spot area based on the change over time of the blind spot area identified at the predetermined time and the assumed behavior of the assumed object in the blind spot area, and a recording medium having the computer program recorded thereon, also fall within the technical scope of the present disclosure.

1...vehicle (own vehicle), 2...parked vehicle, 3...pedestrian, 4...bicycle, 5...preceding vehicle, 6...other vehicle, 31...surrounding environment sensor, 50...driving assistance device, 51...control unit, 55...cumulative blind spot area database, 61...surrounding environment detection unit, 63...blind spot area calculation unit, 65...risk estimation unit, 67...driving condition setting unit, 69...notification unit

Claims (5)

1. A driving assistance device that assists driving of a host vehicle based on a risk present around the host vehicle,
a blind spot calculation unit that identifies a blind spot at a predetermined time and calculates a change in area of the blind spot over time as the host vehicle travels;
a risk estimation unit that assumes an object that may be present in the blind spot area identified at the predetermined time, and estimates a potential risk of a collision between the host vehicle and the object that may be present in the blind spot area based on a time change in an area of the blind spot area identified at the predetermined time and an assumed operation of the assumed object in the blind spot area;
A driving assistance device comprising: 2. The driving assistance device according to claim 1, wherein the risk estimation unit estimates the potential risk by setting the object that may be present in the blind spot area and an intrusion speed of the object ahead of the vehicle based on a change over time in an area of the blind spot area. 3. The driving assistance device according to claim 1, wherein the risk estimation unit determines the object that may be present in the blind spot area, a set speed range of the object within the blind spot area, and a set trajectory of the object based on a change over time in an area of the blind spot area, and estimates the potential risk. a notification control unit that notifies an occupant of the vehicle;
The driving assistance device according to any one of claims 1 to 3, wherein the notification control unit starts a notification when the potential risk exists, and stops the notification when the potential risk no longer exists, even before the host vehicle passes beside an obstruction that caused the blind spot area. A driving condition setting unit that sets driving conditions of the host vehicle,
The driving support device according to any one of claims 1 to 4, wherein the driving condition setting unit sets the driving conditions so as to reduce the potential risk when the potential risk exists, and terminates setting of the driving conditions that reduce the potential risk when the potential risk no longer exists even before the host vehicle passes beside an obstacle that was causing the blind spot area.