Driving assistance control device, driving assistance method, and computer program

Abstract

To suppress a rear-end collision with a following vehicle during deceleration of a vehicle by deceleration stop control.SOLUTION: The driving support control device 6 of the vehicle 100 is configured to perform the driving support for controlling at least the brake actuator 52 of the vehicle 100 to stop the vehicle 100 when it is determined that the driver of the vehicle 100 is in the abnormal state in which it is difficult for the driver to continue driving the vehicle 100, and control the brake actuator 52 such that the deceleration of the vehicle 100 decreases when the inter-vehicle distance between the vehicle 100 and the following vehicle increases stepwise during the deceleration by the driving support.SELECTED DRAWING: Figure 1

Description

[Technical Field]

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

[0002] Patent Document 1 discloses a conventional vehicle driving control device that is configured to perform deceleration / stop control to decelerate the vehicle and keep it stopped when it is determined that the driver is in an abnormal state where he or she has lost the ability to drive the vehicle. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-109559 Summary of the Invention [Problem to be solved by the invention]

[0004] If deceleration / stop control is performed without taking into consideration the following vehicle, there is a risk of the vehicle being rear-ended by the following vehicle when the vehicle is decelerating (braking) due to the deceleration / stop control.

[0005] The present invention has been made in view of these problems, and has as its object to prevent a rear-end collision with a following vehicle when the vehicle is decelerating due to deceleration and stop control. [Means for solving the problem]

[0006] In order to solve the above problem, a driving assistance control device for a vehicle according to one aspect of the present invention is configured to provide driving assistance by controlling at least the vehicle's brake actuator to stop the vehicle when it is determined that the vehicle driver is in an abnormal state that makes it difficult for him or her to continue driving the vehicle, and to control the brake actuator so that the deceleration of the vehicle decreases when the distance between the vehicle and a following vehicle increases in a stepped manner during deceleration due to driving assistance.

[0007] In addition, a vehicle driving assistance method according to one aspect of the present invention is implemented by a control device, and when it is determined that the vehicle driver is in an abnormal state that makes it difficult for him or her to continue driving the vehicle, driving assistance is implemented by controlling at least the vehicle's brake actuator to stop the vehicle, and when the distance between the vehicle and a following vehicle increases in a stepped manner during deceleration due to driving assistance, the brake actuator is controlled so as to reduce the deceleration of the vehicle.

[0008] Furthermore, a computer program according to one aspect of the present invention causes a computer to execute processing to implement driving assistance by controlling at least the vehicle's brake actuator to stop the vehicle when it is determined that the driver of the vehicle is in an abnormal state that makes it difficult for him or her to continue driving the vehicle, and to control the brake actuator so as to reduce the deceleration of the vehicle when the distance between the vehicle and a following vehicle increases in a stepped manner during deceleration due to driving assistance. [Effects of the Invention]

[0009] According to these aspects of the present invention, it is possible to prevent the vehicle from being hit from behind when the vehicle is decelerating due to the deceleration and stop control. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a schematic configuration diagram of a vehicle according to an embodiment of the present invention; [Figure 2] FIG. 10 is a diagram illustrating a problem that occurs when a first following vehicle and a second following vehicle are present behind a vehicle undergoing deceleration and stop control. [Figure 3] 3 is a flowchart illustrating deceleration and stop control according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0011] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the following description, like components are designated by like reference numerals.

[0012] FIG. 1 is a schematic diagram of a vehicle 100 according to an embodiment of the present invention.

[0013] The vehicle 100 includes a surrounding sensor 1, a vehicle sensor 2, a driver sensor 3, an HMI (Human Machine Interface) 4, an actuator 5, and a control device 6. The surrounding sensor 1, the vehicle sensor 2, the driver sensor 3, the HMI 4, the actuator 5, and the control device 6 are communicatively connected to each other via an in-vehicle network 9 that complies with a standard such as a controller area network.

[0014] The surrounding sensor 1 is a sensor for generating surrounding data that represents the situation around the vehicle 100. In this embodiment, the surrounding sensor 1 includes one or more external cameras 11 for capturing images of the surroundings of the vehicle 100, and one or more distance measuring sensors 12 for measuring distances to various targets, such as other vehicles, that exist around the vehicle 100.

[0015] The external camera 11 captures the surroundings of the vehicle 100 at a predetermined frame rate (for example, 10 [Hz] to 40 [Hz]) and generates a surrounding image showing the surroundings of the vehicle 100. Every time the external camera 11 generates a surrounding image, it transmits the generated surrounding image to the control device 6 as surrounding data.

[0016] The distance measurement sensor 12 irradiates a distance measurement area around the vehicle with laser light, radio waves, ultrasonic waves, or the like, and receives reflected light of the irradiated laser light or reflected waves of the irradiated radio waves or ultrasonic waves. The distance measurement sensor 12 then measures the distance to various targets present within the distance measurement area based on the received reflected light or reflected waves. The distance measurement sensor 12 transmits distance measurement data, which associates the distance to each target with coordinate information of each target, to the control device 6 as peripheral data. Examples of the distance measurement sensor 12 include a LiDAR (Light Detection and Ranging) that irradiates radar light and measures distance based on the reflected light, and a millimeter-wave radar sensor that irradiates radio waves and measures distance based on the reflected waves.

[0017] The vehicle sensors 2 are sensors for generating vehicle data that represent the state of the vehicle 100. The vehicle 100 according to this embodiment includes, as the vehicle sensors 2, a speed sensor 21 that generates speed data that indicates the traveling speed of the vehicle 100, and a positioning sensor 22 that generates current position data that indicates the current position of the vehicle 100, such as latitude and longitude. However, the vehicle sensors 2 are not limited to these sensors. The data acquired by the sensors 21 and 22 is transmitted to the control device 6 as vehicle data.

[0018] The driver sensor 3 is a sensor for generating driver data that represents the state of the driver. The vehicle 100 according to this embodiment is equipped with a driver monitor camera 31 as the driver sensor 3 for capturing an image of the driver's appearance, including the driver's face. The driver monitor camera 31 captures an image of the driver's appearance at a predetermined frame rate (for example, 10 [Hz] to 40 [Hz]) and generates an appearance image showing the driver's appearance. Every time the driver monitor camera 31 generates an appearance image of the driver, it transmits the generated appearance image to the control device 6 as driver data.

[0019] The HMI 4 is a user interface for exchanging information between the vehicle 100 and its occupants. The HMI 4 includes an output device 41 for notifying the vehicle occupants through their bodily senses (for example, vision, hearing, and touch), and an input device 42 for the vehicle occupants to perform input operations and response operations. The output device 41 is, for example, a display (for example, a meter display, a center display, a head-up display, etc.) or a speaker. The input device 42 is, for example, a touch panel or a microphone.

[0020] The HMI 4 notifies the vehicle occupant of information corresponding to the output signal received from the control device 6 via the output device 41, and transmits data input by the vehicle occupant to the control device 6 via the input device 42.

[0021] The HMI 4 may be pre-installed in the vehicle 100, or may be a terminal such as a smartphone owned by a vehicle occupant. In the latter case, for example, information may be exchanged between the vehicle 100 and the vehicle occupant's terminal by short-range wireless communication, or information may be exchanged indirectly via communication between the vehicle occupant's terminal and an external server (not shown).

[0022] The actuator 5 is a device used for driving control of the vehicle 100. The vehicle 100 according to this embodiment includes, as the actuators 5, an acceleration actuator 51 (for example, at least one of an engine and a motor) that controls acceleration of the vehicle 100, a brake actuator 52 (for example, a hydraulic actuator) that controls braking of the vehicle 100, and a steering actuator 53 (for example, a steering motor) that controls steering of the vehicle 100.

[0023] The control device 6 is an ECU (Electronic Control Unit) including a communication unit 61, a storage unit 62, and a processing unit 63.

[0024] The communication unit 61 includes an interface circuit for connecting the control device 6 to the in-vehicle network 9. The communication unit 61 supplies various data received from various sensors, the HMI 4, etc. to the processing unit 63. The communication unit 61 also outputs various signals output from the processing unit 63 to the HMI 4, the actuator 5, etc.

[0025] The storage unit 62 has a storage medium such as a hard disk drive (HDD), a solid disk drive (SSD), or a semiconductor memory, and stores various computer programs and data used for processing by the processing unit 63.

[0026] The processing unit 63 has one or more CPUs (Central Processing Units) and their peripheral circuits, and executes various computer programs stored in the storage unit 62. The processing unit 63 is, for example, a processor. The processing unit 63 may further include other arithmetic circuits such as a logic operation unit, a numerical operation unit, or a graphics processing unit. The processing unit 63 executes processing in accordance with the computer programs, thereby functioning as a recognition unit 71, a vehicle distance monitoring unit 72, and a driving assistance unit 73, and operates as functional units (modules) that realize predetermined functions. In the following description, when processing is described using each of the functional units 71 to 73 as the subject, it indicates that the processing unit 63 is executing a program that realizes each of the functional units 71 to 73.

[0027] The following describes the specific processing carried out by the control device 6. That is, the details of the functional units 71 to 73 realized by the processing unit 63 executing processing in accordance with a computer program will be described.

[0028] The recognition unit 71 recognizes targets and features around the vehicle 100. For example, the recognition unit 71 sequentially inputs surrounding images received from the external camera 11 into a classifier, thereby recognizing targets in the surrounding images, such as other vehicles, motorcycles, and pedestrians, as well as features, such as curbs, fences, and similar structures (hereinafter referred to as "demarcation features") and road markings (e.g., lane markings). The classifier may be, for example, a convolutional neural network (CNN) having multiple convolution layers connected in series from the input side to the output side. The recognition unit 71 also calculates the distances from the vehicle to the targets and features and the positions of the targets and features using, for example, standard sizes of the targets and features stored in the memory unit 62 for each type of target and feature and the sizes of the targets and features recognized in the surrounding images. Furthermore, the recognition unit 71 recognizes targets such as other vehicles present around the vehicle and detects the distance to the targets by, for example, grouping, among the multiple reflection points detected by the distance measurement sensor 12, reflection points that satisfy a predetermined condition as reflection points of laser light or the like reflected from the same object. Note that the method for recognizing targets and features is not limited to this method, and various known methods may be used for recognition.

[0029] When the recognition unit 71 recognizes a following vehicle (another vehicle or a two-wheeled vehicle) directly behind the vehicle 100 traveling in the same driving lane as the vehicle 100, the inter-vehicle distance monitoring unit 72 monitors the inter-vehicle distance to the following vehicle measured by the distance measuring sensor 12.

[0030] The driving assistance unit 73 controls the actuators 5 based on the targets and features recognized by the recognition unit 71, and performs driving assistance involving driving control of the vehicle 100. In this embodiment, the driving assistance unit 73 can perform driving assistance involving driving control of the vehicle 100 at a driving control level of Level 3 defined by the Society of Automotive Engineers (SAE), that is, a driving control level that does not require the driver to operate the actuators 51 to 53 or monitor the surroundings. Furthermore, the driving assistance unit 73 can perform driving assistance involving driving control of the vehicle 100 at a driving control level in which the driver is involved in driving the vehicle 100, for example, a driving control level of Level 1 or Level 2 defined by the SAE.

[0031] As one of the driving assistances involving driving control of the vehicle 100, the driving assistance unit 73 controls the vehicle 100 to decelerate at a predetermined deceleration D [m / s 2 ] (e.g., 4.0 [m / s 2 ]) or less, and deceleration / stop control is performed to hold the vehicle 100 in a stopped state.

[0032] Here, when the deceleration / stop control is performed, if the following vehicle is not taken into consideration, a rear-end collision with the following vehicle may occur due to the performance of the deceleration / stop control. For example, as shown in Fig. 2, when a first following vehicle A and a second following vehicle B are present behind the vehicle 100, if the driver of the vehicle 100 falls into an abnormal state that makes it difficult for him to continue driving and the deceleration / stop control is performed on the vehicle 100, the first following vehicle A directly behind the vehicle 100 is likely to take action (for example, change lanes or overtake) to avoid the vehicle 100 as the vehicle 100 decelerates.

[0033] On the other hand, the driver of the second following vehicle B does not necessarily notice the deceleration of the vehicle 100 two vehicles ahead. In such a case, the second following vehicle B notices that the vehicle 100 is decelerating only after the first following vehicle A has avoided the vehicle 100. As a result, the deceleration of the second following vehicle B is delayed. When the vehicle 100 is performing deceleration / stop control, the vehicle 100 decelerates in order to stop the vehicle. Therefore, if the deceleration of the second following vehicle B is delayed, the speed difference between the vehicle 100 and the second following vehicle B is likely to increase, and there is a risk that the second following vehicle B will rear-end the vehicle 100 that is undergoing deceleration / stop control. In particular, if the driver of the first following vehicle A is late in noticing the deceleration of the vehicle 100 and the driver of the first following vehicle A suddenly takes action to avoid the vehicle 100, the speed difference between the vehicle 100 and the second following vehicle B is likely to increase, and there is a high possibility that the second following vehicle B will rear-end the vehicle 100 that is undergoing deceleration / stop control.

[0034] Therefore, in this embodiment, when the distance between vehicle 100 and the following vehicle monitored by vehicle distance monitoring unit 72 changes stepwise and becomes larger while deceleration and stop control is being performed, that is, when it is considered that the following vehicle behind vehicle 100 has changed from first following vehicle A, one vehicle behind, to second following vehicle B, two vehicles behind, the deceleration of vehicle 100 is reduced below the normal deceleration.

[0035] FIG. 3 is a flowchart illustrating the deceleration and stop control according to this embodiment.

[0036] In step S1, the control device 6 determines whether the driver has fallen into an abnormal state (hereinafter simply referred to as "abnormal state") that makes it difficult for the driver to continue driving. In this embodiment, the control device 6 determines that the driver has fallen into an abnormal state if a predetermined estimated abnormal state continues for a predetermined time T1. If the driver has fallen into an abnormal state, the control device 6 proceeds to processing in step S2. On the other hand, if the driver has not fallen into an abnormal state, the control device 6 ends this processing.

[0037] The estimated abnormal state is a state in which the driver is deemed to be in an abnormal state. For example, an example of the estimated abnormal state is a state in which the driver is not operating the steering wheel when driving assistance involving driving control of the vehicle 100 is being performed at a driving control level of level 2 or lower. Whether or not the driver is operating the steering wheel can be determined, for example, based on the magnitude of the steering torque acting on the steering shaft that rotates integrally with the steering wheel. Furthermore, regardless of the driving control level, it can also be determined whether or not the driver is in an estimated abnormal state based on the driver's appearance, for example, based on an image from a driver monitor camera.

[0038] In this embodiment, when the estimated abnormal state continues for a predetermined time T0 (T0 is a time shorter than T1), a warning is issued to the driver via the HMI. This allows deceleration and stop control to be performed only when the vehicle is in an abnormal state where the driver cannot respond to the warning.

[0039] In step S2, the control device 6 starts deceleration and stop control. Specifically, the control device 6 starts deceleration and stop control when the deceleration of the vehicle 100 reaches a predetermined first deceleration D1 (for example, 4.0 [m / s 2 ]), thereby starting deceleration of the vehicle 100. At this time, in addition to the brake control of the vehicle 100, steering control may be performed so that the vehicle 100 travels along the travel lane or the travel path of the preceding vehicle, for example.

[0040] In step S3, the control device 6 determines whether the inter-vehicle distance between the vehicle 100 and the following vehicle has increased in a stepwise manner. For example, if the inter-vehicle distance between the vehicle 100 and the following vehicle measured by the distance measurement sensor 12 has increased by a predetermined value or more compared to the most recent measurement result, the control device 6 can determine that the inter-vehicle distance between the vehicle 100 and the following vehicle has increased in a stepwise manner. Furthermore, for example, the control device 6 can also determine that the inter-vehicle distance between the vehicle 100 and the following vehicle has increased in a stepwise manner when it detects, based on the surrounding image captured by the external camera 11, that the following vehicle has performed an action to avoid the vehicle 100 (for example, changing lanes or overtaking). If the inter-vehicle distance between the vehicle 100 and the following vehicle has increased in a stepwise manner, the control device 6 proceeds to processing in step S4. On the other hand, if the inter-vehicle distance between the vehicle 100 and the following vehicle has not increased in a stepwise manner, the control device 6 proceeds to processing in step S7.

[0041] In step S4, the control device 6 determines whether the deceleration of the vehicle 100 reaches a predetermined second deceleration D2 (for example, 2.0 [m / s 2 ]) to decelerate the vehicle 100. That is, the deceleration of the vehicle 100 is reduced from the first deceleration D1 to the second deceleration D2, thereby making the deceleration of the vehicle 100 gentler.

[0042] In step S5, the control device 6 determines whether the vehicle 100 has stopped. If the vehicle 100 has stopped, the control device 6 proceeds to the processing of step S6. On the other hand, if the vehicle 100 has not stopped, the control device 6 returns to the processing of step S4 and continues decelerating the vehicle 100 at the second deceleration rate D2.

[0043] In step S6, the control device 6 automatically activates, for example, a parking brake, to keep the vehicle 100 stopped.

[0044] In step S7, the control device 6 determines whether the vehicle 100 has stopped. If the vehicle 100 has stopped, the control device 6 proceeds to the processing of step S6. On the other hand, if the vehicle 100 has not stopped, the control device 6 returns to the processing of step S2 and continues decelerating the vehicle 100 at the first deceleration D1.

[0045] The control device 6 (driving assistance control device) of the vehicle 100 according to the present embodiment described above is configured to perform driving assistance by controlling at least the brake actuator 52 of the vehicle 100 to stop the vehicle 100 when it is determined that the driver of the vehicle 100 is in an abnormal state that makes it difficult for him to continue driving the vehicle 100, and to control the brake actuator 52 so as to reduce the deceleration of the vehicle 100 when the distance between the vehicle 100 and a following vehicle increases in a stepped manner during deceleration due to driving assistance.

[0046] Specifically, the control device 6 is configured to control the brake actuator 52 so that the deceleration of the vehicle 100 becomes a predetermined first deceleration D1, thereby starting deceleration of the vehicle 100, and when the distance between the vehicle 100 and the following vehicle increases in a stepped manner, to control the brake actuator 52 so that the deceleration of the vehicle 100 becomes a predetermined second deceleration D2 that is smaller than the first deceleration D1.

[0047] As a result, even if a following vehicle (first following vehicle A) one vehicle behind vehicle 100 takes action to avoid vehicle 100, such as changing lanes, while a following vehicle (second following vehicle B) two vehicles behind vehicle 100 is unaware that vehicle 100 is decelerating due to deceleration stop control, the deceleration of vehicle 100 is reduced and the deceleration of vehicle 100 is made gradual, thereby preventing the following vehicle (second following vehicle B) two vehicles behind vehicle 100 from rear-ending vehicle 100.

[0048] Although the embodiments of the present invention have been described above, the above embodiments merely illustrate some of the application examples of the present invention, and it is not intended that the technical scope of the present invention be limited to the specific configurations of the above embodiments.

[0049] For example, in the above embodiment, the computer program executed by the control device 6 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. Also, in the above embodiment, the control device 6 determines whether the driver is in an abnormal state, but the determination may be made by another control device, and the control device 6 may acquire the determination result. [Explanation of symbols]

[0050] 6. Control device 11 External camera (imaging device) 100 vehicles

Claims

1. A driving assistance control device for a vehicle, When it is determined that the driver of the vehicle is in an abnormal state in which it is difficult to continue driving the vehicle, a driving assistance is performed to stop the vehicle by controlling at least a brake actuator of the vehicle; When the inter-vehicle distance between the vehicle and a following vehicle increases stepwise during deceleration due to the driving assistance, the brake actuator is controlled so as to reduce the deceleration of the vehicle. Driver assistance control device.

2. When the driving assistance is performed, the brake actuator is controlled to start deceleration of the vehicle so that the deceleration of the vehicle becomes a predetermined first deceleration, and when the inter-vehicle distance between the vehicle and a following vehicle increases in a stepwise manner, the brake actuator is controlled so that the deceleration of the vehicle becomes a predetermined second deceleration that is smaller than the first deceleration. The driving assistance control device according to claim 1 .

3. A vehicle driving assistance method implemented by a control device, comprising: When it is determined that the driver of the vehicle is in an abnormal state in which it is difficult to continue driving the vehicle, a driving assistance is performed to stop the vehicle by controlling at least a brake actuator of the vehicle; When the inter-vehicle distance between the vehicle and a following vehicle increases stepwise during deceleration due to the driving assistance, the brake actuator is controlled so as to reduce the deceleration of the vehicle. Driving assistance methods.

4. When it is determined that the driver of the vehicle is in an abnormal state where it is difficult for the driver to continue driving the vehicle, a driving assistance is performed to stop the vehicle by controlling at least a brake actuator of the vehicle; When the inter-vehicle distance between the vehicle and a following vehicle increases stepwise during deceleration due to the driving assistance, the brake actuator is controlled so as to reduce the deceleration of the vehicle. A computer program that causes a computer to perform a process.

Images