Driving assistance device

Abstract

A driving assistance device (200) comprises a signal recognition unit (210) which is mounted in a host vehicle M and which uses detection results of sensors (100) that detect a position of the host vehicle or a state around the host vehicle to recognize a lighting state of a forward traffic light, being a traffic light existing in a traveling direction of the host vehicle, and a driving control unit (240) that executes driving assistance of the host vehicle in accordance with the lighting state of the forward traffic light, wherein the driving control unit (240) suspends or limits the driving assistance if a plurality of forward traffic lights are recognized, and among the recognized forward traffic lights the lighting states of at least two forward traffic lights differ from each other and the content of the driving assistance cannot be determined.

Description

Driving assistance devices CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is based on Japanese Application No. 2022-171357, filed on October 26, 2022, the contents of which are incorporated herein by reference.

[0002] The present disclosure relates to a driving assistance device.

[0003] There is known a technique for providing driving assistance to a vehicle in accordance with the lighting status of traffic lights present in the vehicle's travel direction (Patent Documents 1 and 2).

[0004] JP 2006-92129 A JP 2010-152494 A

[0005] However, when multiple traffic lights with different lighting conditions are recognized, it may be difficult to identify the traffic light that the vehicle should follow. In this case, the content of the driving assistance cannot be determined, and the driving assistance cannot be stably executed.

[0006] The present disclosure can be realized in the following forms.

[0007] According to one aspect of the present disclosure, there is provided a driving assistance device including: a signal recognition unit that is mounted on a host vehicle and that recognizes a lighting status of a traffic light ahead that is a traffic light present in a traveling direction of the host vehicle by using a detection result of a sensor that detects the position of the host vehicle or a situation around the host vehicle; and a driving control unit that performs driving assistance for the host vehicle according to the lighting status of the traffic light ahead, wherein the driving control unit stops or suppresses the driving assistance when a plurality of traffic lights ahead are recognized and the lighting statuses of at least two of the recognized traffic lights ahead are different from each other and the content of the driving assistance cannot be determined.

[0008] According to this type of driving assistance device, if a mixture of traffic lights with different lighting conditions is recognized and the content of the driving assistance cannot be determined, the driving assistance is stopped or canceled, so that behavior can be determined when the content of the driving assistance cannot be determined, and a decrease in the stability of the driving assistance can be suppressed.

[0009] The above and other objects, features, and advantages of the present disclosure will become more apparent from the following detailed description taken in conjunction with the accompanying drawings, in which Fig. 1 is a block diagram showing a schematic configuration of a driving assistance device according to this embodiment, Fig. 2 is a flowchart showing the procedure of driving assistance processing according to this embodiment, Fig. 3 is an explanatory diagram showing an example of an image acquired in step S10 of the driving assistance processing, and Fig. 4 is an explanatory diagram showing an example of processing in step S40 of the driving assistance processing.

[0010] A. Embodiments: A-1. Device Configuration: A driving assistance device 200 according to the present embodiment, shown in FIG. 1, is mounted on a vehicle M and controls the vehicle M. In this embodiment, the vehicle M is also referred to as the "host vehicle M." In this embodiment, the host vehicle M is a vehicle equipped with an engine. The host vehicle M is also a vehicle capable of performing automatic driving, and is configured to be able to switch between automatic driving and manual driving. "Automatic driving" refers to driving in which engine control, braking control, and steering control are automatically performed on behalf of the occupant. "Manual driving" refers to driving in which the occupant performs operations for engine control (depressing the accelerator pedal), braking control (depressing the brake pedal), and steering control (rotating the steering wheel). Note that the vehicle M is not limited to a vehicle equipped with an engine, and may also be an electric vehicle (EV) or a fuel cell vehicle (FCV).

[0011] The driving assistance device 200 is connected to the information acquisition device 100 and the vehicle operation device 300 via an in-vehicle network such as a Controller Area Network (CAN). The driving assistance device 200 controls the vehicle operation device 300 using information indicating the position of the vehicle M or the situation around the vehicle M acquired by the information acquisition device 100, and performs driving assistance.

[0012] In this embodiment, the driving assistance device 200 performs driving assistance by issuing a warning to the occupant using a screen display, sound, vibration, or the like, and controlling the acceleration / deceleration of the host vehicle M. More specifically, when the driving assistance device 200 recognizes that a red or yellow light is on, the driving assistance device 200 executes at least one of issuing a warning to the occupant to decelerate or stop the host vehicle M, and automatically decelerating or stopping the host vehicle M. Furthermore, when the driving assistance device 200 recognizes that the lighting status has changed from a red light to a green light or a right-turn arrow signal, the driving assistance device 200 executes at least one of issuing a warning to the occupant to start the host vehicle M, and automatically starting the host vehicle M.

[0013] The information acquisition device 100 acquires information regarding the current position, driving status, and surrounding conditions of the host vehicle M. In this embodiment, the information acquisition device 100 includes a camera 110, a GNSS receiver 120, and a wireless communication device 130. The camera 110 captures an image of the host vehicle M in the traveling direction. The "traveling direction" refers to the radial area captured by the camera 110 in front of the host vehicle M. The GNSS receiver 120 detects the current position (longitude and latitude) of the host vehicle M based on GNSS signals received from artificial satellites constituting the Global Navigation Satellite System (GNSS). The wireless communication device 130 performs wireless communication with an intelligent transport system, communication with other vehicles, and communication with roadside wireless devices installed on road facilities such as traffic lights. This allows the exchange of information regarding the status of the host vehicle M and the surrounding conditions. In this embodiment, the "information about the surrounding situation" includes information indicating the lighting status of traffic lights present in the vicinity of the vehicle M (hereinafter also referred to as "light information"). Note that the information acquisition device 100 corresponds to the "sensor" in this disclosure.

[0014] The vehicle operation device 300 includes an engine mechanism 310, a brake mechanism 320, a steering mechanism 330, and a warning device 340. The engine mechanism 310 is composed of a group of devices that perform operations such as opening and closing a throttle valve, igniting an igniter, and opening and closing an intake valve. The brake mechanism 320 is composed of a group of devices related to brake control, such as sensors, motors, valves, and pumps. The steering mechanism 330 is composed of a group of devices related to steering, such as a power steering motor. The warning device 340 is composed of a group of devices that alert the occupants, such as a display device, speaker, and vibration generator.

[0015] In this embodiment, the driving assistance device 200 is configured as a computer including a CPU and a memory. An example of such a computer is an ECU (Electronic Control Unit). The driving assistance device 200 includes a signal recognition unit 210, a first sorting unit 220, a second sorting unit 230, and a driving control unit 240 as functional units realized by the CPU executing a program stored in advance in the memory.

[0016] The signal recognition unit 210 recognizes traffic lights (hereinafter also referred to as "forward traffic lights") present in the direction of travel of the host vehicle M using information acquired by the information acquisition device 100. The first selection unit 220 selects, from the forward traffic lights, traffic lights that control traffic in the lane in which the host vehicle M is traveling (hereinafter also referred to as "host lane traffic lights"). The second selection unit 230 selects, from the forward traffic lights, traffic lights that are present at the intersection closest to the host vehicle M (hereinafter also referred to as "nearest intersection traffic lights"). The driving control unit 240 controls the host vehicle M according to the lighting status of the forward traffic lights, and performs the above-mentioned driving assistance.

[0017] A-2. Driving assistance processing: The driving assistance device 200 executes the driving assistance processing shown in Fig. 2 to control the vehicle operation device 300 and perform driving assistance using information indicating the current position of the vehicle M or the situation around the vehicle M acquired by the information acquisition device 100. The driving assistance processing is executed repeatedly while the driving assistance device 200 is running.

[0018] In step S10, the signal recognition unit 210 acquires an image captured by the camera 110 and performs image analysis processing on the acquired image to recognize the positions and lighting status of traffic lights present in the image. In the example shown in FIG. 3, traffic lights TL1 to TL4 are recognized. Traffic lights TL1 to TL4 correspond to the above-mentioned "forward traffic lights." The lighting status of each recognized traffic light corresponds to the above-mentioned "light information."

[0019] 2, the driving control unit 240 determines whether multiple traffic lights are recognized ahead. If only one traffic light is recognized ahead (step S20: No), the driving control unit 240 performs the driving assistance described above in accordance with the light information of the recognized traffic light ahead (step S82), and the driving assistance device 200 performs step S10 again.

[0020] If multiple traffic lights are recognized (step S20: Yes), the driving control unit 240 determines whether the light information of all the traffic lights ahead is the same (step S30). If the light information of all the traffic lights ahead is the same (step S30: Yes), the driving control unit 240 performs the above-described driving assistance in accordance with the light information commonly indicated by the traffic lights ahead (step S82), and the driving assistance device 200 performs step S10 again.

[0021] If the light information is not uniform (step S30: No), in other words, if the lighting statuses of at least two of the traffic lights ahead are different from each other, the first selection unit 220 selects the traffic lights in the current lane from the traffic lights ahead (step S40). In this embodiment, as shown in the example in Fig. 4, the first selection unit 220 excludes traffic lights TL2 and TL4 included in an exclusion area Ar indicated by hatching from the recognition targets, thereby selecting traffic lights TL1 and TL3 as the traffic lights in the current lane. The exclusion area Ar is preset as a rectangular area with a size determined in advance through experiments or the like.

[0022] In step S50, the second selection unit 230 selects the nearest intersection traffic light from the selected traffic lights in the current lane. In this embodiment, the second selection unit 230 compares the areas of the pixel regions representing traffic lights TL1 and TL3, which are recognized as traffic lights in the current lane, in the acquired image, and excludes traffic light TL3, which has a smaller area than traffic light TL1 and is located farther away, thereby selecting traffic light TL1 as the nearest intersection traffic light. Note that if only one traffic light is selected as the current lane traffic light in step S40, the second selection unit 230 does not need to perform this step.

[0023] In step S60, the driving control unit 240 determines whether the light information of each selected traffic light is a single signal. If the light information is a single signal (step S60: Yes), the driving control unit 240 performs the driving assistance described above in accordance with the light information indicated by the selected traffic light (step S82), and the driving assistance device 200 performs step S10 again.

[0024] If the light information is not a single type (step S60: No), the driving control unit 240 determines whether the driving assistance content can be determined from the light information of each selected traffic light (step S70). For example, if a driving assistance system that alerts the occupant by displaying a screen, making a sound, vibrating, or the like is pre-set as a driving assistance system when a red or yellow light is recognized, it is possible to determine to provide the above-mentioned attention as driving assistance even if the light information of the selected traffic light includes both red and yellow lights. On the other hand, if the above-mentioned attention is pre-set as a driving assistance system when a red light is recognized but not as a driving assistance system when a yellow light is recognized, the driving assistance content cannot be determined if the light information of the selected traffic light includes both red and yellow lights. Another example of a combination of light information that can determine the driving assistance content is when the host vehicle M is located in a straight-only lane and the light information of the selected traffic light includes both red and right-turn arrow signals. When the host vehicle M is located in a straight-through lane, the host vehicle M needs to stop regardless of whether the light status of the traffic light for the host vehicle M is a red light or a right-turn arrow signal, and in this case, driving assistance for stopping the vehicle can be determined. In other words, even if the light statuses of the selected traffic lights are different from each other, the driving control unit 240 can determine the content of driving assistance if there is a common driving assistance among the driving assistances to be performed according to each lighting status.

[0025] If the driving assistance content cannot be determined (step S70: No), the driving control unit 240 cancels or suppresses the driving assistance (step S80). "Canceling" the driving assistance means not executing at least one of the above-mentioned driving assistance contents. Furthermore, "suppressing" the driving assistance means weakening the level of driving assistance, and in this embodiment, at least one of suppressing the acceleration / deceleration of the vehicle M, suppressing the degree of emphasis of the screen display on the display device of the vehicle M, suppressing the volume of the notification sound, and suppressing vibrations that attract the attention of the occupants is executed. After step S80 is completed, the driving assistance device 200 executes step S10 again.

[0026] If the driving assistance content can be determined (step S70: Yes), the driving control unit 240 executes the determined driving assistance (step S82), and the driving assistance device 200 executes step S10 again.

[0027] According to the driving assistance device 200 described above, when a mixture of traffic lights with different lighting conditions is recognized and the content of driving assistance cannot be determined, driving assistance is stopped or canceled, so that behavior when the content of driving assistance cannot be determined can be determined and a decrease in the stability of driving assistance can be suppressed. Note that "stability of driving assistance" means an index that indicates whether it is possible to determine whether or not to perform driving assistance depending on the position of the host vehicle M or the situation around the host vehicle M.

[0028] In addition, the driving assistance device 200 selects the traffic lights in the vehicle's own lane and performs driving assistance according to the lighting status of the traffic lights in the vehicle's own lane, making it easier to narrow down the traffic lights that are targeted at the vehicle M, thereby further suppressing a decrease in the stability of driving assistance.

[0029] In addition, the driving assistance device 200 selects the nearest intersection traffic light and performs driving assistance according to the lighting status of the nearest intersection traffic light, making it easier to narrow down the traffic lights that are targeted at the vehicle M, thereby further suppressing a decrease in the stability of driving assistance.

[0030] Furthermore, even if the lighting status of at least two of the multiple traffic lights ahead is different from each other, the driving assistance device 200 executes a common driving assistance among the driving assistances that have been pre-set to be executed according to each lighting status, thereby preventing the content of the driving assistance from being unable to be determined and further preventing a decrease in the stability of the driving assistance.

[0031] B. Other Embodiments: (B1) In the above embodiment, the driving assistance device 200 uses images acquired by the camera 110 to select the traffic light in the vehicle's own lane and the nearest intersection traffic light during the driving assistance process. However, the present disclosure is not limited to this. The driving assistance device 200 may select the traffic light in the vehicle's own lane and the nearest intersection traffic light using position information of the vehicle M acquired by the GNSS receiver 120 or light information of traffic lights around the vehicle M received by the wireless communication device 130. The driving assistance device 200 may also be mounted on a vehicle M equipped with a ranging device, and may select the traffic light in the vehicle's own lane and the nearest intersection traffic light using the distance between the vehicle M and the traffic lights around the vehicle M detected by the ranging device. Note that millimeter-wave radar or lidar may be used as the ranging device. A driving assistance device 200 configured in this manner also achieves the same effects as the above embodiment.

[0032] (B2) In the above embodiment, the driving assistance device 200 selects the traffic light in the current lane (step S40) and then selects the traffic light in the nearest intersection (step S50) in the driving assistance process. However, the present disclosure is not limited to this. The driving assistance device 200 may select the traffic light in the current lane after selecting the traffic light in the nearest intersection. Furthermore, the driving assistance device 200 may execute only one of steps S40 and S50 in the driving assistance process. A driving assistance device 200 configured in this manner also achieves the same effects as the above embodiment.

[0033] (B3) In the above embodiment, driving assistance device 200 executes steps S40 to S70 after step S30 in the driving assistance process, but the present disclosure is not limited to this. Driving assistance device 200 may execute step S80 without executing steps S40 to S70, if the lighting information in step S30 is not single (step S30: No). Driving assistance device 200 configured in this manner can also determine behavior when the content of driving assistance cannot be determined, and can suppress a decrease in the stability of driving assistance.

[0034] The present disclosure is not limited to the above-described embodiments and can be realized in various configurations without departing from the spirit thereof. For example, the technical features in each embodiment corresponding to the technical features in the form described in the Summary of the Invention section can be appropriately replaced or combined to solve some or all of the above-described problems or achieve some or all of the above-described effects. Furthermore, if a technical feature is not described as essential in this specification, it can be appropriately deleted.

[0035] The driving assistance device 200 and the method described herein may be implemented by a special-purpose computer configured by configuring a processor and memory programmed to execute one or more functions embodied in a computer program. Alternatively, the driving assistance device 200 and the method described herein may be implemented by a special-purpose computer configured by configuring a processor with one or more dedicated hardware logic circuits. Alternatively, the driving assistance device 200 and the method described herein may be implemented by one or more special-purpose computers configured by combining a processor and memory programmed to execute one or more functions with a processor configured with one or more hardware logic circuits. Furthermore, the computer program may be stored as instructions executed by a computer on a computer-readable non-transitory tangible storage medium.

Claims

1. A driving assistance device (200), A signal recognition unit (210) is mounted on a vehicle (M) and recognizes the lighting status of a forward traffic signal, which is a traffic signal present in the traveling direction of the vehicle, by utilizing a detection result of a sensor (100) that detects the position of the vehicle or the surrounding conditions of the vehicle; A driving control unit (240) that executes driving assistance for the host vehicle according to a lighting state of the forward traffic light; Equipped with When a plurality of the forward traffic lights are recognized, and when the lighting statuses of at least two of the recognized forward traffic lights are different from each other and the content of the driving assistance cannot be determined, the driving control unit stops or suppresses the driving assistance, When a plurality of the forward traffic lights are recognized and the lighting conditions of at least two of the recognized forward traffic lights are different from each other, the driving control unit executes the driving assistance that is common to the driving assistances that are predetermined to be executed according to the lighting conditions. Driving assistance device.

2. The driving assistance device according to claim 1, The vehicle further includes a first selection unit (220) that selects a current lane signal that controls traffic in the lane in which the vehicle is traveling from among the forward traffic signals, the driving control unit, when a plurality of the own lane signals are selected by the first selection unit and the lighting statuses of the own lane signals are the same, executes the driving assistance according to the lighting statuses of the own lane signals. Driving assistance device.

3. The driving assistance device according to claim 1 or 2, A second selection unit (230) is further provided for selecting a nearest intersection traffic light, which is a traffic light present at the intersection nearest to the vehicle, from among the traffic lights ahead, the driving control unit, when a plurality of the nearest intersection traffic lights are selected by the second selection unit and the lighting statuses of the nearest intersection traffic lights are the same, executes the driving assistance according to the lighting statuses of the nearest intersection traffic lights. Driving assistance device.

4. The driving assistance device according to claim 1 or 2, The driving control unit executes at least one of suppressing the acceleration / deceleration of the vehicle, suppressing a degree of emphasis of a screen display on a display device of the vehicle, suppressing a volume of a notification sound, and suppressing a vibration that calls the attention of an occupant, as the suppression of the driving assistance. Driving assistance device.