Driving assistance device and driving assistance method

Abstract

To provide an advantageous technique for appropriately performing driving assistance for a self-vehicle.SOLUTION: A driving assistance device includes: an acquisition section that acquires surrounding vehicle information of a surrounding vehicle through vehicle-to-vehicle communication from the surrounding vehicle on which the driving assistance device is mounted; a prediction section that predicts a possibility of collision between a self-vehicle and the surrounding vehicle on the basis of the surrounding vehicle information and the self-vehicle information representing vehicle speed, location, and a traveling trajectory of the self-vehicle; and a notification section that notifies an occupant of the self-vehicle on the basis of a prediction result. The prediction section sets a first determination area using a location at which the self-vehicle accelerates after decelerating to a threshold value or less or a location at which the self-vehicle temporarily stops as a first reference location and predicts the possibility of collision between the self-vehicle and surrounding vehicle in the first determination area in a case where the surrounding vehicle is present within a first range in front of the self-vehicle, and sets a second determination area using an intersection point between predicted courses of the self-vehicle and the surrounding vehicle as a second reference location and predicts the possibility of collision between the self-vehicle and the surrounding vehicle in the second determination area in a case where the surrounding vehicle is present in a second range on a side of the self-vehicle.SELECTED DRAWING: Figure 10

Description

[Technical field]

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

[0002] In recent years, efforts to provide access to sustainable transportation systems that take into consideration vulnerable traffic participants have been gaining momentum. To achieve this, research and development is being focused on research and development of preventive safety technology to further improve traffic safety and convenience. A device that performs driving assistance to prevent collisions with other vehicles (surrounding vehicles) without using map information is known. Patent Document 1 discloses a driving assistance device that registers in a storage unit position information of an intersection where the travel path of the vehicle and the travel path of the other vehicle intersect, and provides driving assistance to the vehicle when passing through the intersection again. Patent Document 2 discloses a technology for predicting a collision based on a speed vector calculated based on the immediate movement direction of the other vehicle and the traveling direction of the vehicle. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 7054636 [Patent Document 2] JP 2022-61482 A Summary of the Invention [Problem to be solved by the invention]

[0004] The driving assistance device may identify a risk position where the host vehicle may collide with another vehicle based on the travel trajectory of the host vehicle and the travel trajectory of the other vehicle, and may use the risk position for driving assistance. However, even if an intersection is actually present in the traveling direction of the host vehicle, driving assistance using the risk position cannot be performed until the intersection is identified as a risk position. Some aspects of the present disclosure aim to provide a technology that is advantageous for appropriately performing driving assistance for the host vehicle, and ultimately contribute to the development of a sustainable transportation system. [Means for solving the problem]

[0005] According to some embodiments, a driving assistance device includes: an acquisition means for acquiring surrounding vehicle information indicating a vehicle speed, a position, and a driving trajectory of the surrounding vehicles from surrounding vehicles around a host vehicle on which the driving assistance device is mounted, by vehicle-to-vehicle communication; a prediction means for predicting a possibility of a collision between the host vehicle and the surrounding vehicles based on host vehicle information indicating the vehicle speed, the position, and the driving trajectory of the host vehicle and the surrounding vehicle information; and a notification means for notifying an occupant of the host vehicle based on a prediction result by the prediction means, wherein the prediction means detects a collision between the host vehicle and the surrounding vehicles within a first range ahead of the host vehicle, and A driving assistance device is provided that, when a surrounding vehicle is present, sets a first judgment area using a position where the host vehicle accelerates after decelerating to below a threshold value or a position where the host vehicle stops as a first reference position, and predicts the possibility of a collision between the host vehicle and the surrounding vehicle in the first judgment area, and, when the surrounding vehicle is present within a second range to the side of the host vehicle, sets a second judgment area using an intersection of a predicted path of the host vehicle and a predicted path of the surrounding vehicle as a second reference position, and predicts the possibility of a collision between the host vehicle and the surrounding vehicle in the second judgment area. Effect of the Invention

[0006] According to some embodiments, an advantageous technique is provided for appropriately providing driving assistance for a vehicle. [Brief description of the drawings]

[0007] [Figure 1] FIG. 1 is a block diagram illustrating an example configuration of a vehicle according to some embodiments. [Diagram 2] FIG. 13 illustrates an example of risk location information according to some embodiments. [Diagram 3] 11A and 11B are schematic diagrams illustrating examples of trajectory intersections according to some embodiments. [Figure 4] FIG. 1 is a flow diagram illustrating an example of a method for registering nearby vehicles according to some embodiments. [Diagram 5] FIG. 4 is a schematic diagram illustrating an example of a range that includes surrounding vehicles according to some embodiments. [Figure 6] FIG. 11 is a flow diagram illustrating an example of a driving assistance operation regarding a nearby vehicle ahead according to some embodiments. [Figure 7] 1 is a schematic diagram illustrating an example of a driving assistance operation regarding a nearby vehicle ahead according to some embodiments; [Figure 8] 1 is a schematic diagram illustrating an example of a driving assistance operation regarding a nearby vehicle ahead according to some embodiments; [Figure 9] FIG. 11 is a flow diagram illustrating an example of a driving assistance operation regarding a nearby vehicle to the side according to some embodiments. [Figure 10] 1 is a schematic diagram illustrating an example of a driving assistance operation regarding a nearby vehicle to the side according to some embodiments. [Figure 11] 10A and 10B are schematic diagrams illustrating an example of a method for determining a nearby vehicle to be determined according to some embodiments. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] Hereinafter, the embodiments will be described in detail with reference to the accompanying drawings. Note that the following embodiments do not limit the invention according to the claims, and not all combinations of features described in the embodiments are essential to the invention. Two or more features among the multiple features described in the embodiments may be arbitrarily combined. In addition, the same reference numbers are used for the same or similar configurations, and duplicated descriptions are omitted.

[0009] <Vehicle configuration example> With reference to FIG. 1, a configuration example of a vehicle 100 according to some embodiments will be described. As shown in FIG. 1, the vehicle 100 may include a sensor group 101, a Global Navigation Satellite System (GNSS) antenna 102, a vehicle-to-vehicle communication antenna 103, a notification device 104, a braking device 105, and a control device 106. FIG. 1 shows the components referred to in the following description, but the vehicle 100 may include other components for operating as a vehicle, such as a drive device, a transmission, and lighting devices. In addition to or instead of this, the vehicle 100 may not include some of the components shown in FIG. 1. The vehicle 100 may be a four-wheeled vehicle, a two-wheeled vehicle, or another type of vehicle.

[0010] The control device 106 controls the overall operation of the vehicle 100. As described later, the control device 106 executes driving assistance for the vehicle 100 in which the control device 106 is mounted. Therefore, the control device 106 may be called a driving assistance device. The driving assistance provided by the control device 106 may be collision prevention assistance for preventing (reducing) collisions with other vehicles. In some embodiments, the control device 106 can execute collision prevention assistance without using map information. In the following description, the vehicle 100 may be referred to as the host vehicle 100 in order to easily distinguish it from other vehicles. Also, a vehicle different from the vehicle 100 may be referred to as another vehicle. Among the other vehicles, a vehicle currently present around the host vehicle 100 may be referred to as a surrounding vehicle. The surrounding vehicle may be a vehicle currently capable of vehicle-to-vehicle communication with the host vehicle 100.

[0011] The sensor group 101 includes various sensors for performing driving assistance for the vehicle 100. For example, the sensor group 101 may include a speed sensor that detects the speed of the vehicle 100, an acceleration sensor that detects the acceleration of the vehicle 100, and the like. The sensor group 101 may also include external detection sensors such as a camera, a millimeter wave radar, and a lidar (Light Detection and Ranging: LIDAR) that can detect objects around the vehicle 100. The sensor group 101 outputs the detection results to the control device 106.

[0012] The GNSS antenna 102 receives radio waves for position measurement transmitted from GNSS satellites. For example, the GNSS antenna 102 can be used to obtain information on the current position and / or travel path (travel history) of the vehicle 100. The vehicle-to-vehicle communication antenna 103 is an antenna for transmitting and receiving various data to and from surrounding vehicles. For example, the vehicle-to-vehicle communication antenna 103 can be used to obtain information on the current position, speed, and travel path of the surrounding vehicles.

[0013] The notification device 104 is a device that notifies the occupants (e.g., the driver) of the vehicle 100. When there is a possibility that the vehicle 100 will collide with a surrounding vehicle, the control device 106 can notify the occupants of the vehicle 100 of the possibility of a collision with the surrounding vehicle by the notification device 104 as driving assistance. For example, the notification device 104 may include a display unit such as a display and display information indicating the possibility of a collision with the surrounding vehicle on the display unit, or may include an audio output unit such as a speaker and output information indicating the possibility of a collision with the surrounding vehicle from the audio output unit by voice or the like.

[0014] The braking device 105 is a device, such as a brake, for performing a braking operation of the vehicle 100. When there is a possibility that the vehicle 100 will collide with a surrounding vehicle, the control device 106 operates the braking device 105 as a driving assistance to assist in decelerating the vehicle 100, thereby making it possible to avoid a collision with the surrounding vehicle.

[0015] The control device 106 is a device (computer) that controls the vehicle 100, and can be configured, for example, by an ECU (Electric Control Unit). The control device 106 can perform driving assistance by vehicle-to-vehicle communication with other vehicles and processing within the vehicle 100. For example, the control device 106 can perform driving assistance without using map information. The control device 106 includes a processing unit 110, a storage unit 111, a GNSS module 113, and a vehicle-to-vehicle communication module 114, which are connected by a bus (not shown).

[0016] The processing unit 110 is a processor represented by a CPU (Central Processing Unit), and executes a program stored in the storage unit 111. The storage unit 111 includes, for example, a RAM (Random Access Memory), a ROM (Read Only Memory), a hard disk, and the like, and stores a program (driving assistance program) for the processing unit 110 to execute driving assistance processing of the vehicle 100, a program (learning program) for the processing unit 110 to learn risk positions, various data, and the like. The storage unit 111 may store risk position information 112 created based on an intersection between the travel trajectory of the vehicle 100 and the travel trajectory of another vehicle. The risk position information 112 may include a plurality of risk positions. The risk position may be a position where the vehicle 100 may collide with another vehicle, or a position where there is a high possibility of such a collision. The risk position information 112 may be managed as a database.

[0017] The GNSS module 113 receives position information of the vehicle 100 and the like from GNSS satellites via the GNSS antenna 102. In addition, the vehicle-to-vehicle communication module 114 receives various types of information from other vehicles via the vehicle-to-vehicle communication antenna 103.

[0018] The processing unit 110 may include an acquisition unit 110a, a prediction unit 110b, a support unit 110c, and an update unit 110d in order to execute driving support (collision prevention support in some embodiments) for the vehicle 100. Note that the processing unit 110 is not limited to a configuration including the units 110a to 110d. Other units may be added or some units may be omitted depending on the type of driving support executed by the vehicle 100.

[0019] The acquisition unit 110a acquires surrounding vehicle information indicating the current position, vehicle speed, and traveling trajectory of the surrounding vehicle from the surrounding vehicles existing around the vehicle 100 via the vehicle-to-vehicle communication antenna 103 (vehicle-to-vehicle communication module 114). The surrounding vehicle information may explicitly or implicitly indicate the current position, vehicle speed, and traveling trajectory of the surrounding vehicle. For example, the surrounding vehicle information may include the vehicle speed as it is, or may include information for calculating the vehicle speed (current and immediately preceding two geographical positions and their positioning times). The acquisition unit 110a may acquire host vehicle information indicating the current position, speed, and traveling trajectory of the vehicle 100 via the sensor group 101 and the GNSS antenna 102 (GNSS module 113).

[0020] The prediction unit 110b predicts the possibility of the vehicle 100 colliding with another vehicle based on the host vehicle information and the surrounding vehicle information acquired by the acquisition unit 110a. The prediction unit 110b may set a judgment area and predict the possibility of the vehicle 100 colliding with another vehicle in the judgment area. The prediction unit 110b may also provide driving assistance for the vehicle 100 based on the risk position information 112. For example, when at least one risk position among multiple risk positions included in the risk position information 112 is located near the host vehicle, the prediction unit 110b may set the judgment area to include the risk position.

[0021] The support unit 110c performs driving support (collision prevention support) for the vehicle 100 based on the prediction result by the prediction unit 110b. In some embodiments, the support unit 110c may perform at least one of a notification to the occupants of the vehicle 100 by the notification device 104 and deceleration support for the vehicle 100 by the braking device 105 as driving support for the vehicle 100.

[0022] The update unit 110d identifies an intersection between the travel trajectory of the vehicle 100 and the travel trajectory of the surrounding vehicle. The intersection between the travel trajectory of the vehicle 100 and the travel trajectory of the surrounding vehicle is hereinafter referred to as a trajectory intersection. There is a possibility that a road intersection exists near the trajectory intersection. In addition, the update unit 110d updates the risk location information 112 stored in the storage unit 111 based on the identified trajectory intersection. For example, the update unit 110d may update the risk location information 112 by adding the trajectory intersection to the risk location information 112. Alternatively or in addition to this, the update unit 110d may update the risk location information 112 by correcting any risk location included in the risk location information 112 based on the trajectory intersection.

[0023] Next, an example of the risk location information 112 will be described with reference to FIG. 2. In the example of FIG. 2, the risk location information 112 is described in a table format, but the risk location information 112 may be in another format. The risk location information 112 has a record for each risk location. The columns of the risk location information 112 shown in FIG. 2 are an example. The risk location information 112 may include other columns, or may not include some of the columns shown in FIG. 2.

[0024] The risk location information 112 may include information on a risk location ID, a registration date and time, coordinates, and a passing direction for each risk location. The risk location ID is a number that uniquely identifies the risk location. The registration date and time is the date and time when the risk location is registered in the risk location information 112. The coordinates are data for identifying the risk location, and are represented by, for example, latitude and longitude data. The coordinates may include altitude data such as altitude in addition to latitude and longitude data. The passing direction is the direction (direction, angle) in which the vehicle 100 was facing when passing the trajectory intersection used to determine the risk location. The passing direction may be understood as the traveling direction (approaching direction) of the vehicle 100 when entering the trajectory intersection. In the example of FIG. 2, the passing direction of the vehicle 100 is specified as 0° northward, 90° eastward, 180° southward, and 270° westward.

[0025] Next, an example of a trajectory intersection will be described with reference to FIG. 3. As described above, a trajectory intersection is an intersection between the travel trajectory of the vehicle 100 and the travel trajectory of another vehicle. In this specification, a case where the vehicle 100 is traveling in an area where driving on the right side is mandatory will be described. In this case, the oncoming lane side of the vehicle 100 means the left side of the vehicle 100. The embodiment described in this specification is also applicable to a case where the vehicle 100 is traveling in an area where driving on the right side is mandatory. In this case, the oncoming lane side of the vehicle 100 means the right side of the vehicle 100.

[0026] In the example shown in FIG. 3(a), the position where the traveling trajectory 301a of the host vehicle 100 traveling straight north and the traveling trajectory 302a of the other vehicle OVA traveling straight west intersects is the trajectory intersection point CPa. Note that the timing (time) at which the host vehicle 100 passes through the trajectory intersection point CPa is different from the timing (time) at which the other vehicle OVA passes through the trajectory intersection point CPa, so there is no collision between the host vehicle 100 and the other vehicle OVA. The traveling trajectory 301a of the host vehicle 100 is included in the host vehicle information acquired by the acquisition unit 110a via the sensor group 101 and the GNSS antenna 102 (GNSS module 113). The traveling trajectory 302a of the other vehicle OVA is included in the other vehicle information acquired by the acquisition unit 110a via the vehicle-to-vehicle communication antenna 103 (vehicle-to-vehicle communication module 114). Since the other vehicle OVa at the time of acquisition is a nearby vehicle that exists around the host vehicle 100, the other vehicle information may be understood as nearby vehicle information.

[0027] In the example shown in Fig. 3(b), the position where the travel trajectory 301b of the host vehicle 100 that travels straight north and turns left intersects with the travel trajectory 302b of the other vehicle OVb that travels straight south is the trajectory intersection CPb. Note that the timing (time) at which the host vehicle 100 passes the trajectory intersection CPb is different from the timing (time) at which the other vehicle OVb passes the trajectory intersection CPb, so no collision occurs between the host vehicle 100 and the other vehicle OVb. Similarly to the travel trajectory 301a, the travel trajectory 301b of the host vehicle 100 is included in the host vehicle information acquired by the acquisition unit 110a via the sensor group 101 and the GNSS antenna 102 (GNSS module 113). The travel path 302b of the other vehicle OVb, like the travel path 302a, is included in the other vehicle information (surrounding vehicle information) acquired by the acquisition unit 110a via the inter-vehicle communication antenna 103 (inter-vehicle communication module 114).

[0028] The functions of the control device 106 can be realized by either hardware or software. For example, the functions of the control device 106 may be realized by the processing unit 110 (CPU) executing a driving assistance program and / or a learning program as described above, or may be realized by an integrated circuit such as a PLD (Programmable Logic Device) or an ASIC (Application Specific Integrated Circuit). In the example of FIG. 1, the control device 106 is shown as a single element, but may be divided into two or more elements as necessary.

[0029] <Management of surrounding vehicles> An example of a process for managing surrounding vehicles will be described with reference to Fig. 4. The process shown in the flowchart of Fig. 4 is executed by the processing unit 110 in accordance with a learning program read from the storage unit 111. The process of Fig. 4 may be started, for example, in response to the ignition of the vehicle 100 being turned on. The process of Fig. 4 may be repeatedly executed until the ignition of the vehicle 100 is turned off.

[0030] In step S401, the processing unit 110 (e.g., the acquisition unit 110a) determines whether or not another vehicle is present around the host vehicle 100. If it is determined that another vehicle is present around the host vehicle 100, the processing unit 110 transitions the process to step S402, and otherwise transitions the process to step S404. For example, the processing unit 110 may determine that another vehicle is present around the host vehicle 100 when vehicle-to-vehicle communication can be performed via the vehicle-to-vehicle communication antenna 103 (vehicle-to-vehicle communication module 114).

[0031] In step S402, the processing unit 110 (e.g., the acquisition unit 110a) registers the other vehicle found in step S401 as a nearby vehicle. For example, the storage unit 111 may store a list of nearby vehicles, and the processing unit 110 may add information about the found nearby vehicle to this list. As described below, the nearby vehicles are targets for determining the possibility of collision.

[0032] In step S403, the processing unit 110 (e.g., the acquisition unit 110a) starts acquiring surrounding vehicle information from the surrounding vehicles through vehicle-to-vehicle communication. As described above, the surrounding vehicle information may represent the vehicle speed, position, and driving trajectory of the surrounding vehicles. After starting to acquire the surrounding vehicle information in step S402, the processing unit 110 repeatedly acquires the surrounding vehicle information periodically (e.g., every 100 ms) until vehicle-to-vehicle communication with the surrounding vehicles is no longer possible.

[0033] After starting to acquire the surrounding vehicle information, in step S403, the processing unit 110 (e.g., the acquisition unit 110a) determines whether or not there is a vehicle that is no longer able to perform inter-vehicle communication among one or more registered surrounding vehicles. If such a vehicle is present, the processing unit 110 transitions the process to step S405, and otherwise transitions the process to step S401. For example, if a surrounding vehicle goes out of the communication range of inter-vehicle communication or is powered off, the vehicle 100 will no longer be able to perform inter-vehicle communication with the surrounding vehicle.

[0034] In step S405, the processing unit 110 (e.g., the acquisition unit 110a) cancels the registration of the nearby vehicle with which inter-vehicle communication is no longer possible. In other words, the processing unit 110 does not treat the vehicle with which inter-vehicle communication is no longer possible as a nearby vehicle. For example, the processing unit 110 deletes information about the nearby vehicle with which inter-vehicle communication is no longer possible from the list of nearby vehicles stored in the memory unit 111.

[0035] As described above, the processing unit 110 can periodically acquire the latest surrounding vehicle information from other vehicles (that is, surrounding vehicles) in the vicinity of the host vehicle 100 by executing the process in FIG.

[0036] <Driving assistance processing> The driving assistance process of some embodiments will be described with reference to Figs. 5 to 10. As described with reference to Fig. 3(a), when the other vehicle is included in the range to the side of the host vehicle 100, if the host vehicle 100 and the other vehicle both proceed straight, there is a possibility that these vehicles will collide. On the other hand, as described with reference to Fig. 3(b), when the other vehicle is included in the range in front of the host vehicle 100, there is a possibility that these vehicles will collide if the host vehicle 100 turns left and the other vehicle proceeds straight. In this way, the position where these vehicles may collide (i.e., the risk position) may differ depending on the position of the other vehicle relative to the host vehicle 100. Therefore, in some embodiments, the control device 106 performs different driving assistance depending on whether the surrounding vehicle is present in the range in front of the host vehicle 100 or in the range to the side.

[0037] With reference to FIG. 5, the range for selecting the driving assistance method will be described. The range 500 is located in front of the vehicle 100. The range in front of the vehicle 100 may be a range including the front of the vehicle 100. The range 500 may be a sector-shaped area as shown in FIG. 5, or may have another shape. The range 500 may be symmetrical with respect to the front direction of the vehicle 100. The central angle of the range 500 may be, for example, about 100 degrees to 110 degrees. The range 501 is located on the side of the vehicle 100. The side of the vehicle 100 may be a range including the diagonally forward direction of the vehicle 100. The range 501 may include a direction directly to the side of the vehicle 100. The range 501 may be a sector-shaped area as shown in FIG. 5, or may have another shape. In the example of FIG. 5, the ranges 501 are located on the right and left sides of the vehicle 100. The central angle of the range 501 may be, for example, about 80 degrees to 90 degrees. In the example of Fig. 5, a part of range 500 and a part of range 501 overlap. The central angle of this overlapping part may be, for example, about 10 degrees to 20 degrees. When a nearby vehicle is present in this overlapping part, this nearby vehicle becomes a target of both driving assistance in the situation of Fig. 3(a) and driving assistance in the situation of Fig. 3(b). Instead of the example of Fig. 5, range 500 and range 501 may simply be in contact with each other, or may be separated from each other.

[0038] When the surrounding vehicle is included in the range 501, the control device 106 may collide with another vehicle by moving straight as shown in FIG. 3(a). Therefore, the control device 106 predicts the possibility of a collision caused by the vehicle 100 moving straight. This operation will be described later with reference to FIG. 6 to FIG. 8. On the other hand, when the surrounding vehicle is included in the range 500, the control device 106 may collide with another vehicle by turning left as shown in FIG. 3(b). Therefore, the control device 106 predicts the possibility of a collision caused by the vehicle 100 moving straight. This operation will be described later with reference to FIG. 9 to FIG. 10. The positions of the ranges 500 and 501 relative to the vehicle 100 may be set in advance (for example, when the vehicle 100 is manufactured or when the software is updated) and stored in the storage unit 111.

[0039] FIG. 6 describes an example of a process for executing driving assistance when a nearby vehicle RV (FIG. 7(a)) is present within a range 501 to the side of the vehicle 100. The process shown in the flowchart of FIG. 6 is executed by the processing unit 110 in accordance with a driving assistance program read from the memory unit 111. The process of FIG. 6 may be executed for a nearby vehicle RV each time the nearby vehicle RV is newly registered in step S602 of FIG. 6 while the driving assistance setting is on, for example. In the process of FIG. 6, multiple other vehicles may be registered as nearby vehicles. The process of FIG. 6 is executed for each of these multiple nearby vehicles.

[0040] In step S601, the processing unit 110 (e.g., its prediction unit 110b) determines whether the surrounding vehicle RV is present within the range 501 to the side of the host vehicle 100. If it is determined that the surrounding vehicle RV is present within the range 501 to the side of the host vehicle 100, the processing unit 110 transitions the process to step S602, and otherwise repeats step S601. This determination may be made based on the current position of the surrounding vehicle RV included in the latest surrounding vehicle information acquired from the surrounding vehicle RV. In the example shown in FIG. 7(a), the surrounding vehicle RV is present within the range 501.

[0041] In step S602, the processing unit 110 (for example, its prediction unit 110b) judges whether the predicted path of the host vehicle 100 and the predicted path of the surrounding vehicle RV intersect. If it is judged that these predicted paths intersect, the processing unit 110 transitions the process to step S603, and otherwise repeats step S602. The predicted path may be a half line extending from the vehicle to the front. In the example shown in FIG. 7(a), the predicted path 700 of the host vehicle 100 and the predicted path 701 of the surrounding vehicle RV intersect. The intersection of the predicted path 700 of the host vehicle 100 and the predicted path 701 of the surrounding vehicle RV is represented as a predicted intersection 702. The predicted path 700 of the host vehicle 100 may be determined based on host vehicle information (specifically, the current position and the driving trajectory). The processing unit 110 may acquire the latest host vehicle information at this point. The predicted course 701 of the surrounding vehicle RV may be determined based on the latest surrounding vehicle information (specifically, the current position and traveling trajectory).

[0042] In step S603, the processing unit 110 (for example, the prediction unit 110b) sets a judgment area using the predicted intersection 702 as a reference position, and stores the judgment area in the storage unit 111. The judgment area may be an area in which a collision possibility is predicted. With reference to FIG. 7(a), an example of the judgment area 703 set using the predicted intersection 702 as a reference position will be described. The judgment area 703 may be a rectangle including the predicted intersection 702 and including sides parallel to the predicted path 700 of the vehicle 100. Alternatively, the judgment area 703 may have another shape. The position and shape of the judgment area 703 relative to the predicted intersection 702 may be set in advance (for example, when the vehicle 100 is manufactured or when the software is updated) and stored in the storage unit 111. When a risk position exists near the judgment area 703, the processing unit 110 may expand the judgment area 703 to include the risk position.

[0043] As shown in FIG. 7(a), the processing unit 110 may set a determination region 703 of a different shape (size) for a case where the surrounding vehicle RV is on the right side of the host vehicle 100 (i.e., the opposite side to the oncoming lane) and a case where the surrounding vehicle RV is on the left side of the host vehicle 100 (i.e., the oncoming lane) as shown in FIG. 7(b). Whether the surrounding vehicle RV is on the right side or the left side of the host vehicle 100, the length 704 in the vehicle width direction of the determination region 703 may be the same length (for example, 3 m to 4 m, which is the length of one lane). The length 705 in the vehicle length direction of the determination region 703 when the surrounding vehicle RV is on the right side of the host vehicle 100 may be longer than the length 705 in the vehicle length direction of the determination region 703 when the surrounding vehicle RV is on the left side of the host vehicle 100. The length 705 in the vehicle length direction of the determination region 703 when the surrounding vehicle RV is on the right side of the host vehicle 100 may be, for example, 9 m to 11 m, which is a length equivalent to three lanes. The length 705 in the vehicle length direction of the determination region 703 when the surrounding vehicle RV is on the left side of the host vehicle 100 may be, for example, 6 m to 8 m, which is a length equivalent to two lanes.

[0044] Whether the surrounding vehicle RV is on the right or left side of the host vehicle 100, the distance between the side of the determination area 703 farther from the host vehicle 100 and the predicted intersection 702 may be the same (for example, about 1.5 m corresponding to a half lane). As a result, the length 706 of the portion of the determination area 703 that is closer to the host vehicle 100 than the predicted intersection 702 when the surrounding vehicle RV is on the right side of the host vehicle 100 is greater than the length 706 of the portion of the determination area 703 that is closer to the host vehicle 100 than the predicted intersection 702 when the surrounding vehicle RV is on the left side of the host vehicle 100. When the surrounding vehicle RV is on the right side of the host vehicle 100, there is a possibility that an oncoming lane of the lane in which the surrounding vehicle RV is traveling exists between the predicted intersection 702 and the host vehicle 100. Therefore, by expanding the determination area 703 toward the host vehicle 100, it is possible to suppress a collision with another vehicle (which may not have a vehicle-to-vehicle communication function) traveling in this oncoming lane.

[0045] In step S604, the processing unit 110 (for example, the prediction unit 110b) predicts the possibility of a collision between the host vehicle 100 and the surrounding vehicle RV in the judgment area 703. The processing unit 110 transitions the process to step S605 when it is determined that there is a possibility of a collision between the host vehicle 100 and the surrounding vehicle RV, and transitions the process to step S607 otherwise.

[0046] The collision possibility may be determined based on a predicted time (hereinafter simply referred to as "arrival time") for the surrounding vehicle RV to reach the predicted node 702. This arrival time may be calculated, for example, based on the latest surrounding vehicle information acquired from the surrounding vehicle RV. For example, the processing unit 110 can predict the predicted time for the surrounding vehicle RV to reach the predicted node 702 by dividing the distance between the surrounding vehicle RV and the predicted node 702 by the speed of the surrounding vehicle RV.

[0047] The processor 110 may determine that there is a possibility of a collision if the arrival time is equal to or less than a time threshold, and may determine that there is no possibility of a collision if the arrival time is greater than the time threshold. The time threshold may be configurable by an occupant of the host vehicle 100.

[0048] The processing unit 110 may change the time threshold value according to the speed of the surrounding vehicle RV. FIG. 8 is a diagram showing the relationship between the speed of the surrounding vehicle RV and the stopping time of the surrounding vehicle RV. The stopping time of the surrounding vehicle RV is the time it takes for the surrounding vehicle RV to stop at a deceleration (e.g., 0.4 G) due to a general brake operation. FIG. 8 shows a specified range (upper speed limit, lower speed limit) regarding the speed of the surrounding vehicle RV, and an upper time limit and a lower time limit regarding the time to collision (TTC). The specified range is the speed range of the surrounding vehicle RV within which driving assistance of the host vehicle 100 is performed. The upper time limit is the upper limit of the time to collision set arbitrarily by the driver or the like, and the lower time limit is the lower limit of the time to collision set based on the measurement position accuracy of the GNSS.

[0049] The processing unit 110 sets the stop time corresponding to the speed of the surrounding vehicle RV as the time threshold based on the "relationship between the speed and the stop time of the surrounding vehicle RV" represented by the line 800 in FIG. 8. In the region 801 above the line 800, the arrival time is longer than the stop time, and if the driver of the surrounding vehicle RV performs a normal braking operation (e.g., deceleration of 0.4G), the surrounding vehicle RV can be stopped before it reaches the predicted intersection 702. Therefore, when the arrival time is longer than the time threshold (stop time), the driving assistance of the host vehicle SV may be suppressed. On the other hand, in the region 802 below the line 800, the arrival time is shorter than the stop time, and even if the driver of the surrounding vehicle RV performs a normal braking operation (e.g., deceleration of 0.4G), the surrounding vehicle RV can reach the predicted intersection 702 before it stops. Therefore, when the arrival time is equal to or shorter than the time threshold (stop time), the driving assistance of the host vehicle SV may be executed. The processing unit 110 may change the time threshold continuously or stepwise according to the speed of the surrounding vehicle RV.

[0050] The possibility of collision may be determined based on the host vehicle 100 entering the judgment area 703, instead of or in addition to the arrival time required for the surrounding vehicle RV to reach the predicted intersection 702. For example, the processing unit 110 may determine that there is a possibility of collision when the host vehicle 100 has entered the judgment area 703, and may determine that there is no possibility of collision when the host vehicle 100 has not entered the judgment area 703.

[0051] Furthermore, the collision possibility may be determined based on the difference between the predicted time for the surrounding vehicle RV to reach the predicted intersection 702 and the predicted time for the host vehicle 100 to reach the predicted intersection 702 (hereinafter referred to as "arrival time difference"). The processing unit 110 may determine that there is a collision possibility when the arrival time difference is equal to or less than a time threshold, and may determine that there is no collision possibility when the arrival time difference is greater than the time threshold. The time threshold may be set by an occupant of the host vehicle 100.

[0052] The possibility of collision may be determined by any combination of the above three conditions (i.e., the arrival time is equal to or less than a time threshold, the host vehicle 100 has entered the judgment area 703, and the arrival time difference is equal to or less than another time threshold). For example, the processing unit 110 may determine that there is a possibility of collision when all of these three conditions are satisfied, and determine that there is no possibility of collision otherwise. Alternatively, the processing unit 110 may determine that there is a possibility of collision when at least one of these three conditions is satisfied, and determine that there is no possibility of collision otherwise. Alternatively, the processing unit 110 may determine that there is a possibility of collision when at least one of two pre-set conditions of these three conditions is satisfied, and determine that there is no possibility of collision otherwise. Specifically, the processing unit 110 may predict that there is a possibility of collision if the arrival time difference is greater than a second time threshold when the predicted time until the surrounding vehicle RV arrives at the predicted intersection 702 is smaller than a first time threshold, and predict that there is no possibility of collision if the arrival time difference is smaller than the second time threshold.

[0053] In step S605, the processing unit 110 (for example, the support unit 110c) determines whether the support condition is satisfied. If it is determined that the support condition is satisfied, the processing unit 110 transitions the process to step S606, and otherwise transitions the process to step S607. The support condition may be a condition that must be satisfied in order to execute driving support. For example, the support condition may be based on whether the speed of the surrounding vehicle RV is within a specified range. The specified range may be set in advance by a lower speed limit value and an upper speed limit value regarding the speed of the surrounding vehicle RV. If the speed of the surrounding vehicle RV is equal to or lower than the lower speed limit value of the specified range, the driver of the surrounding vehicle RV is likely to notice the host vehicle 100 and decelerate the surrounding vehicle RV without colliding with the host vehicle 100. In other words, the lower speed limit value of the specified range regarding the speed of the surrounding vehicle RV may be set to a value that allows the surrounding vehicle RV to decelerate without colliding with the host vehicle 100. Furthermore, when the speed of the surrounding vehicle RV is equal to or greater than the upper limit of the specified range, the surrounding vehicle RV is highly likely not to be a vehicle traveling on the road into which the host vehicle 100 enters, such as traveling on an expressway near the road into which the host vehicle 100 enters. In other words, the upper limit of the specified range regarding the speed of the surrounding vehicle RV can be set to a value that makes it possible to determine whether the surrounding vehicle RV is a vehicle traveling on the road into which the host vehicle 100 enters, or a vehicle traveling on an expressway near the road. In this way, by executing / suppressing driving assistance depending on whether the speed of the surrounding vehicle RV is within the specified range, it is possible to reduce the annoyance felt by the driver of the host vehicle 100 from the driving assistance.

[0054] In step S606, the processing unit 110 (for example, the support unit 110c) performs driving support for the host vehicle 100. As driving support for the host vehicle 100, the processing unit 110 can notify the occupants of the host vehicle 100 of a possibility of a collision using the notification device 104 and can perform a braking operation for the host vehicle 100 using the braking device 150.

[0055] In step S608, the processing unit 110 (for example, the prediction unit 110b) deletes the judgment area (the judgment area stored in step S603) that has become unnecessary due to the execution of the driving assistance from the storage unit 111. This prevents the capacity of the storage unit 111 from being consumed by unnecessary information.

[0056] When it is determined in step S604 that there is no possibility of collision or when it is determined in step S605 that the assistance condition is not satisfied, step S607 is executed. In step S607, the processing unit 110 (for example, its prediction unit 110b) determines whether the surrounding vehicle RV to be processed in the method of FIG. 6 has been deregistered in step S405 of FIG. 4. When it is determined that the registration of the surrounding vehicle RV has been deregistered, the processing unit 110 transitions the processing to step S608, and otherwise transitions the processing to step S602. When the registration of the surrounding vehicle RV has been deregistered, it is considered that the surrounding vehicle RV no longer exists in the vicinity of the host vehicle 100. Therefore, the processing unit 110 ends the processing without performing driving assistance regarding the collision with this surrounding vehicle RV. In this case as well, in step S608, the processing unit 110 (for example, its prediction unit 110b) deletes the unnecessary determination area from the storage unit 111.

[0057] If it is determined in step S607 that the registration of the surrounding vehicle RV has not been cancelled, the process returns to step S602. In this case, if the predicted path of the vehicle 100 and the predicted path of the surrounding vehicle RV still intersect, a judgment area is set in step S603 with the predicted intersection 702 as a reference position. If a vehicle (the vehicle 100 or the surrounding vehicle RV) changes its position within a lane or changes lanes, the position of the predicted intersection 702 may change. Since the surrounding vehicle information is repeatedly acquired, the processing unit 110 can detect such a change in the position of the predicted intersection 702. Therefore, in step S603, the processing unit 110 (for example, its prediction unit 110b) resets the reference position based on the newly acquired surrounding vehicle information, and accordingly updates the judgment area stored in the storage unit 111. As a result, the judgment in step S604 is performed based on the updated judgment area. In step S603, if the predicted intersection 902 cannot be determined (for example, if the predicted path 900 of the vehicle 100 and the predicted path 901 of the surrounding vehicle RV no longer intersect), the most recently determined reference position and judgment area are maintained.

[0058] According to the method of FIG. 6, when multiple surrounding vehicles are present within the range 501 to the side of the vehicle 100, an individual reference position is used for each of the multiple surrounding vehicles. Specifically, the method of FIG. 6 is executed for each of the multiple surrounding vehicles individually. As a result, a predicted intersection between the predicted path of the vehicle 100 and the predicted path of the surrounding vehicle is also determined for each of the multiple surrounding vehicles. As a result, an individual judgment area is set for each of the multiple surrounding vehicles based on the individual reference position. This makes it possible to appropriately predict the possibility of a collision with each of the multiple surrounding vehicles.

[0059] FIG. 9 describes an example of a process for executing driving assistance when a nearby vehicle RV (FIG. 10) is present within a range 500 ahead of the host vehicle 100. The process shown in the flowchart of FIG. 9 is executed by the processing unit 110 in accordance with a learning program read from the storage unit 111. The process of FIG. 9 may be started, for example, in response to the driving assistance setting being turned on. The process of FIG. 9 may be repeatedly executed until the driving assistance setting is turned off or the ignition of the vehicle 100 is turned off.

[0060] In step S901, the processing unit 110 (for example, its prediction unit 110b) judges whether the host vehicle 100 accelerates or stops after decelerating to a threshold value or less. If it is judged that the host vehicle 100 accelerates or stops after decelerating to a threshold value or less, the processing unit 110 transitions the process to step S902, and otherwise repeats step S901. This judgment may be made based on the vehicle speed and acceleration of the host vehicle 100 included in the latest host vehicle information. The threshold used in step S901 is a value below which the vehicle speed after decelerating to turn (for example, turn left or turn right) is lowered, and may be, for example, 20 km per hour. The position where the host vehicle 100 accelerates or stops after decelerating to a threshold value or less is represented as a turning preparation position 1001 (FIG. 10). It should be noted that the host vehicle 100 may accelerate or stop temporarily after decelerating to a threshold value or less even if it does not turn. Even in this case, the processing unit 110 detects the turning preparation position 1001 and executes the processes in and after step S902.

[0061] In step S902, the processing unit 110 (for example, the prediction unit 110b) sets a judgment area using the turning preparation position 1001 as a reference position, and stores the reference position and the judgment area in the storage unit 111. The judgment area may be an area in which a collision possibility is predicted. With reference to FIG. 10, an example of the judgment area 1002 set using the turning preparation position 1001 as a reference position will be described. The judgment area 1002 may be a rectangle centered on the left front position of the turning preparation position 1001 and including sides parallel to the vehicle length direction of the host vehicle 100. The length of the judgment area 1002 in the vehicle width direction of the host vehicle 100 may be, for example, 3 m to 4 m, which is a length equivalent to one lane. The length of the judgment area 1002 in the vehicle length direction of the host vehicle 100 may be, for example, 9 m to 11 m, which is a length equivalent to three lanes. The lower right corner of the judgment area 1002 may overlap the turning preparation position 1001. Alternatively, the judgment area 1002 may have another shape. The position of the judgment area 1002 relative to the reference position may be set in advance (for example, when the vehicle 100 is manufactured or when the software is updated) and stored in the storage unit 111. When a risk position exists near the judgment area 1002, the processing unit 110 may expand the judgment area 1002 to include the risk position. The processing unit 110 sets the judgment area 1002 to include the turning preparation position 1001 (i.e., the reference position) and to be offset toward the oncoming lane (left side in the example of FIG. 10) with respect to the host vehicle 100 in a direction perpendicular to the predicted path of the host vehicle 100. This makes it possible to appropriately predict the possibility of a collision that may occur when the host vehicle 100 turns left.

[0062] In step S903, the processing unit 110 (e.g., its prediction unit 110b) determines a predicted turning trajectory 1004 of the host vehicle 100. The predicted turning trajectory 1004 may be a turning trajectory predicted when the host vehicle 100 turns (e.g., turns left) to an oncoming lane. The predicted turning trajectory 1004 may be set in advance (e.g., when the vehicle 100 is manufactured or when the software is updated) and stored in the storage unit 111. The predicted turning trajectory 1004 set in advance in this manner may be called a default predicted turning trajectory 1004.

[0063] A plurality of candidates of the predicted turning trajectory 1004 may be stored in the memory unit 111. The processing unit 110 (e.g., its prediction unit 110b) may select one predicted turning trajectory 1004 from the plurality of candidates of the predicted turning trajectory 1004 based on the steering angle of the host vehicle 100 at the turning preparation position 1001, and use the selected predicted turning trajectory 1004 for subsequent processing. For example, when the steering angle of the host vehicle 100 is small, the processing unit 110 may select the predicted turning trajectory 1004 with a small radius of curvature since it is considered that the host vehicle 100 is about to turn left at a small intersection. On the other hand, when the steering angle of the host vehicle 100 is large, the processing unit 110 may select the predicted turning trajectory 1004 with a large radius of curvature since it is considered that the host vehicle 100 is about to turn left at a large intersection.

[0064] In step S904, the processing unit 110 (e.g., its prediction unit 110b) identifies a surrounding vehicle RV present within the range 500 in front of the host vehicle 100 as a target vehicle for subsequent processing. If no surrounding vehicle RV exists within the range 500, no target vehicle is identified. If multiple surrounding vehicles RV exist within the range 500, all of these multiple surrounding vehicles RV are identified as target vehicles. This identification may be performed based on the current position of the surrounding vehicle RV included in the latest surrounding vehicle information acquired from the surrounding vehicle RV. In the example shown in FIG. 10, one surrounding vehicle RV exists within the range 500.

[0065] In step S905, the processing unit 110 (for example, the prediction unit 110b) predicts the possibility of a collision between the host vehicle 100 and the surrounding vehicle RV in the judgment area 1002. The processing unit 110 transitions the process to step S906 when it is determined that there is a possibility of a collision between the host vehicle 100 and the surrounding vehicle RV, and transitions the process to step S908 otherwise.

[0066] The possibility of collision may be determined based on whether an intersection 1005 between the predicted turning trajectory 1004 determined in step S903 and a predicted path 1003 of the surrounding vehicle RV is included in the judgment region 1002. For example, the processing unit 110 may determine that there is a possibility of collision when the intersection 1005 is included in the judgment region 1002, and may determine that there is no possibility of collision when the intersection 1005 is not included in the judgment region 1002.

[0067] In step S906, the processing unit 110 (for example, the support unit 110c) judges whether the support condition is satisfied. If it is judged that the support condition is satisfied, the processing unit 110 transitions the process to step S907, otherwise, the processing unit 110 transitions the process to step S908. Step S906 may be the same as step S605, and therefore a duplicated description will be omitted.

[0068] In step S907, the processing unit 110 (for example, the support unit 110c) performs driving support for the host vehicle 100. As driving support for the host vehicle 100, the processing unit 110 can notify the occupants of the host vehicle 100 of a possibility of a collision using the notification device 104 and can perform a braking operation for the host vehicle 100 using the braking device 150.

[0069] In step S910, the processing unit 110 (for example, the prediction unit 110b) deletes the reference position and the determination area (the reference position and the determination area stored in step S603) that have become unnecessary due to the execution of the driving assistance from the storage unit 111. This prevents the capacity of the storage unit 111 from being consumed by unnecessary information.

[0070] If it is determined in step S905 that there is no possibility of collision or if it is determined in step S906 that the assistance condition is not satisfied, step S908 is executed. In step S908, the processing unit 110 (for example, its prediction unit 110b) determines whether the host vehicle 100 has moved a predetermined distance (for example, 30 m) or more from the reference position stored in step S902. If it is determined that the host vehicle 100 has moved a predetermined distance or more from the reference position, the processing unit 110 transitions the processing to step S910, and otherwise transitions the processing to step S909. If the host vehicle 100 has moved a predetermined distance or more from the reference position, it is considered that there is no possibility that the host vehicle 100 will collide with the surrounding vehicle RV at that point. Therefore, the processing unit 110 ends the processing without performing driving assistance regarding the collision with this surrounding vehicle RV. In this case as well, in step S910, the processing unit 110 (for example, its prediction unit 110b) deletes the reference position and the determination area that are no longer necessary from the storage unit 111.

[0071] Step S909 is executed when it is determined in step S909 that the host vehicle 100 is not away from the reference position by a predetermined distance or more. In step S909, the processing unit 110 (e.g., the prediction unit 110b) may update the predicted turning trajectory 1004 based on a change in the steering angle of the host vehicle 100. For example, the processing unit 110 may update the predicted turning trajectory 1004 so that the radius of curvature becomes smaller when the host vehicle 100 turns left at a steering angle larger than that assumed in the predicted turning trajectory 1004. On the other hand, the processing unit 110 may update the predicted turning trajectory 1004 so that the radius of curvature becomes larger when the host vehicle 100 turns left at a steering angle smaller than that assumed in the predicted turning trajectory 1004. The predicted turning trajectory 1004 may be updated when the current steering angle of the host vehicle 100 becomes equal to or larger than the steering angle of the default predicted turning trajectory 1004. Thereafter, the processing unit 110 transitions the process to step S904, and specifies the surrounding vehicle RV that is newly included in the range 500 as a target vehicle for subsequent processing. In addition, the collision possibility in step S905 is determined based on the updated predicted turning trajectory 1004.

[0072] 9, when multiple surrounding vehicles are present within the range 500 ahead of the vehicle 100, a common reference position (i.e., turning preparation position 1001) is used for the multiple surrounding vehicles. As a result, a common judgment area is set for each of the multiple surrounding vehicles based on the common reference position. This allows the possibility of a collision when the vehicle 100 turns to the oncoming lane (for example, when turning left) to be appropriately estimated.

[0073] In the above-described driving assistance method, the surrounding vehicle RV is set as a target for collision possibility prediction based on the fact that the surrounding vehicle RV is located within the range 500 or 501 in Fig. 5. The processing unit 110 may determine whether or not to set the surrounding vehicle RV as a target for collision possibility prediction based on other information. With reference to Fig. 11, an example of a method for determining the surrounding vehicle RV as a target for collision possibility prediction will be described.

[0074] The processing unit 110 may determine whether the surrounding vehicle RV is to be a target for collision possibility prediction based on a rotation angle 1103 of a course vector 1102 of the surrounding vehicle RV relative to the course vector 1101 of the host vehicle 100. The course vector 1101 may be a unit vector facing the traveling direction of the vehicle. For the sake of explanation, the rotation angle 1103 is positive in the clockwise direction and negative in the counterclockwise direction. The processing unit 110 can determine the approach direction of the surrounding vehicle RV based on the direction of the surrounding vehicle RV relative to the host vehicle 100 and the rotation angle 1103 of the course vector 1102 of the surrounding vehicle RV relative to the course vector 1101 of the host vehicle 100.

[0075] Even if the surrounding vehicle RV is included in the range 500 in front of the host vehicle 100, if the surrounding vehicle RV is traveling in the same direction as the host vehicle 100 or traveling to the right or left of the host vehicle 100, it is considered that there is no possibility of a collision between the host vehicle 100 and the surrounding vehicle RV. Therefore, the processing unit 110 may determine whether or not the surrounding vehicle RV is a collision possibility determination target in the processing of Figs. 6 and 9 when the surrounding vehicle RV is included in the range 500 in front of the host vehicle 100 and the rotation angle 1103 is included in a predetermined range (for example, 160° to 200°).

[0076] Even if the surrounding vehicle RV is included in the range 501 on the right side of the host vehicle 100, if the surrounding vehicle RV is traveling in the same direction as the host vehicle 100 or in the opposite direction, or traveling to the right of the host vehicle 100, it is considered that there is no possibility of a collision between the host vehicle 100 and the surrounding vehicle RV. Therefore, the processing unit 110 may determine whether or not the surrounding vehicle RV is a collision possibility determination target in the processing of Figs. 6 and 9 when the surrounding vehicle RV is included in the range 501 on the right side of the host vehicle 100 and the rotation angle 1103 is included in a predetermined range (for example, -110° to -70°).

[0077] Even if the surrounding vehicle RV is included in the range 501 on the left side of the host vehicle 100, if the surrounding vehicle RV is traveling in the same direction as the host vehicle 100 or in the opposite direction, or traveling to the left of the host vehicle 100, it is considered that there is no possibility of a collision between the host vehicle 100 and the surrounding vehicle RV. Therefore, the processing unit 110 may determine whether or not the surrounding vehicle RV is a collision possibility determination target in the processing of Figs. 6 and 9 when the surrounding vehicle RV is included in the range 501 on the left side of the host vehicle 100 and the rotation angle 1103 is included in a predetermined range (for example, 70° to 110°).

[0078] According to the above-described embodiment, it is possible to appropriately predict the possibility of a collision depending on the position of the surrounding vehicle. As a result, it is possible to appropriately perform driving assistance for the vehicle 100. Note that even in a situation where driving assistance based on surrounding vehicle information acquired from the surrounding vehicles through vehicle-to-vehicle communication is not performed, driving assistance based on other criteria (for example, based on the detection results of a camera or radar) may be performed.

[0079] <Summary of the embodiment> [Item 1] A driving assistance device (106), An acquisition means (110a) for acquiring surrounding vehicle information indicating a vehicle speed, a position, and a traveling trajectory of a surrounding vehicle (RV) existing around a host vehicle (100) equipped with the driving assistance device by vehicle-to-vehicle communication; a prediction means (110b) for predicting a possibility of a collision between the host vehicle and the surrounding vehicle based on host vehicle information indicating a vehicle speed, a position, and a traveling trajectory of the host vehicle and the surrounding vehicle information; and a notification means (110c) for notifying an occupant of the vehicle based on a result of the prediction by the prediction means, The prediction means includes: When the surrounding vehicle is present within a first range (500) in front of the host vehicle, a first judgment area (1002) is set using a position where the host vehicle accelerates after decelerating to a threshold value or below or a position where the host vehicle stops as a first reference position (1001), and a possibility of a collision between the host vehicle and the surrounding vehicle in the first judgment area is predicted; A driving assistance device which, when the surrounding vehicle is present within a second range (501) to the side of the host vehicle, sets a second judgment area (703) using the intersection of the predicted path (700) of the host vehicle and the predicted path (701) of the surrounding vehicle as a second reference position (702), and predicts the possibility of a collision between the host vehicle and the surrounding vehicle in the second judgment area. According to this item, the possibility of a collision can be predicted with high accuracy, and as a result, driving assistance can be provided appropriately. [Item 2] The driving assistance device described in item 1, wherein when the surrounding vehicle is present within the first range, the prediction means predicts that there is a possibility of a collision between the host vehicle and the surrounding vehicle based on the fact that an intersection between a predicted turning trajectory (1004) previously set for the host vehicle and a predicted course (1003) of the surrounding vehicle is included in the first judgment area. This item allows for more accurate prediction of the likelihood of a collision. [Item 3] 3. The driving assistance device according to item 2, wherein the prediction means updates the predicted turning trajectory based on a change in a steering angle of the host vehicle. This item allows for more accurate prediction of the likelihood of a collision. [Item 4] The driving assistance device according to item 2 or 3, wherein the prediction means selects the predicted turning trajectory from a plurality of predicted turning trajectory candidates based on a steering angle of the host vehicle at the first reference position. This item allows for more accurate prediction of the likelihood of a collision. [Item 5] The driving assistance device according to any one of claims 1 to 4, wherein the prediction means sets the first judgment area so as to include the first reference position and to be offset toward an oncoming lane relative to the host vehicle in a direction perpendicular to the predicted path of the host vehicle. This item allows for more accurate prediction of the likelihood of a collision. [Item 6] the prediction means sets the second determination area having a different shape depending on whether the surrounding vehicle present within the second range is on an oncoming lane side relative to the host vehicle or whether the surrounding vehicle present within the second range is on an opposite side to the oncoming lane side relative to the host vehicle; The driving assistance device according to any one of items 1 to 6, wherein a length (706) of a portion of the second judgment area that is closer to the host vehicle than the second reference position when the surrounding vehicle is on the opposite side of the oncoming lane to the host vehicle is greater than a length (706) of a portion of the second judgment area that is closer to the host vehicle than the second reference position when the surrounding vehicle is on the oncoming lane to the host vehicle. This item allows for more accurate prediction of the likelihood of a collision. [Item 7] When the nearby vehicle is present within the second range and a first predicted time until the nearby vehicle reaches the second reference position is smaller than a first time threshold, the prediction means predicting a possibility of a collision between the host vehicle and the surrounding vehicle if a difference between a second predicted time until the host vehicle reaches the second reference position and the first predicted time is smaller than a second time threshold; 8. The driving assistance device according to claim 1, wherein if the difference between the second predicted time and the first predicted time is greater than the second time threshold, it predicts that there is no possibility of a collision between the host vehicle and the surrounding vehicle. This item allows for more accurate prediction of the likelihood of a collision. [Item 8] A driving assistance method executed by a vehicle (100), comprising: An acquisition step (S403) of acquiring surrounding vehicle information indicating a vehicle speed, a position, and a traveling trajectory of the surrounding vehicle from surrounding vehicles existing around the host vehicle by vehicle-to-vehicle communication; a prediction step (S604, S905) of predicting a possibility of a collision between the host vehicle and the surrounding vehicle based on host vehicle information indicating a vehicle speed, a position, and a traveling trajectory of the host vehicle and the surrounding vehicle information; and a notification step (S606, S907) of notifying an occupant of the host vehicle based on a result of the prediction step, The prediction step includes: When the surrounding vehicle is present within a first range (500) in front of the host vehicle, a first judgment area (1002) is set using a position where the host vehicle accelerates after decelerating to a threshold value or below, or a position where the host vehicle stops, as a first reference position (1001), and a possibility of a collision between the host vehicle and the surrounding vehicle in the first judgment area is predicted (S907); When the surrounding vehicle is present within a second range (501) to the side of the host vehicle, setting a second judgment area (703) using an intersection of a predicted path (700) of the host vehicle and a predicted path (701) of the surrounding vehicle as a second reference position (702), and predicting (S606) the possibility of a collision between the host vehicle and the surrounding vehicle in the second judgment area. According to this item, the possibility of a collision can be predicted with high accuracy, and as a result, driving assistance can be provided appropriately. [Item 9] A program for causing a computer mounted on a vehicle (100) to execute each step of a driving assistance method, the driving assistance method comprising: An acquisition step (S403) of acquiring surrounding vehicle information indicating a vehicle speed, a position, and a traveling trajectory of the surrounding vehicle from surrounding vehicles existing around the host vehicle by vehicle-to-vehicle communication; a prediction step (S604, S905) of predicting a possibility of a collision between the host vehicle and the surrounding vehicle based on host vehicle information indicating a vehicle speed, a position, and a traveling trajectory of the host vehicle and the surrounding vehicle information; and a notification step (S606, S907) of notifying an occupant of the host vehicle based on a result of the prediction step, The prediction step includes: When the surrounding vehicle is present within a first range (500) in front of the host vehicle, a first judgment area (1002) is set using a position where the host vehicle accelerates after decelerating to a threshold value or below, or a position where the host vehicle stops, as a first reference position (1001), and a possibility of a collision between the host vehicle and the surrounding vehicle in the first judgment area is predicted (S907); When the surrounding vehicle is present within a second range (501) to the side of the host vehicle, setting a second judgment area (703) using an intersection of a predicted path (700) of the host vehicle and a predicted path (701) of the surrounding vehicle as a second reference position (702), and predicting (S606) the possibility of a collision between the host vehicle and the surrounding vehicle in the second judgment area. According to this item, the possibility of a collision can be predicted with high accuracy, and as a result, driving assistance can be provided appropriately.

[0080] The invention is not limited to the above-described embodiment, and various modifications and variations are possible within the scope of the gist of the invention. [Explanation of symbols]

[0081] 100: vehicle, 101: sensor group, 102: GNSS antenna, 103: vehicle-to-vehicle communication antenna, 104: notification device, 105: braking device, 106: control device

Claims

1. A driving assistance device, an acquisition means for acquiring surrounding vehicle information indicating a vehicle speed, a position, and a traveling trajectory of the surrounding vehicle from surrounding vehicles existing around the vehicle equipped with the driving assistance device through vehicle-to-vehicle communication; a prediction means for predicting a possibility of a collision between the host vehicle and the surrounding vehicle based on host vehicle information indicating a vehicle speed, a position, and a traveling trajectory of the host vehicle and the surrounding vehicle information; a notification means for notifying an occupant of the host vehicle based on a result of the prediction by the prediction means, The prediction means includes: When the surrounding vehicle is present within a first range ahead of the host vehicle, a first determination area is set using a position where the host vehicle accelerates after decelerating to a threshold value or below or a position where the host vehicle stops as a first reference position, and a possibility of a collision between the host vehicle and the surrounding vehicle in the first determination area is predicted; A driving assistance device that, when the surrounding vehicle is present within a second range to the side of the host vehicle, sets a second judgment area using the intersection of the predicted path of the host vehicle and the predicted path of the surrounding vehicle as a second reference position, and predicts the possibility of a collision between the host vehicle and the surrounding vehicle in the second judgment area.

2. 2. The driving assistance device according to claim 1, wherein the prediction means predicts that there is a possibility of a collision between the host vehicle and the surrounding vehicle when the surrounding vehicle is present within the first range, based on the fact that an intersection between a predicted turning trajectory previously set for the host vehicle and a predicted course of the surrounding vehicle is included in the first judgment area.

3. The driving support device according to claim 2 , wherein the prediction means updates the predicted turning trajectory based on a change in a steering angle of the host vehicle.

4. The driving support device according to claim 2 , wherein the prediction means selects the predicted turning trajectory from a plurality of candidates of the predicted turning trajectory based on a steering angle of the host vehicle at the first reference position.

5. 2. The driving assistance device according to claim 1, wherein the prediction means sets the first judgment region so as to include the first reference position and to be offset toward an oncoming lane relative to the host vehicle in a direction perpendicular to the predicted path of the host vehicle.

6. the prediction means sets the second determination area having a different shape depending on whether the surrounding vehicle present within the second range is on an oncoming lane side relative to the host vehicle or whether the surrounding vehicle present within the second range is on an opposite side to the oncoming lane side relative to the host vehicle; 2. The driving assistance device according to claim 1, wherein a length of the portion of the second judgment area that is closer to the host vehicle than the second reference position when the surrounding vehicle is on the opposite side of the oncoming lane to the host vehicle is greater than a length of a portion of the second judgment area that is closer to the host vehicle than the second reference position when the surrounding vehicle is on the oncoming lane to the host vehicle.

7. When the nearby vehicle is present within the second range and a first predicted time until the nearby vehicle reaches the second reference position is smaller than a first time threshold, the prediction means predicting a possibility of a collision between the host vehicle and the surrounding vehicle if a difference between a second predicted time until the host vehicle reaches the second reference position and the first predicted time is smaller than a second time threshold; The driving assistance device according to claim 1 , wherein if the difference between the second predicted time and the first predicted time is greater than the second time threshold, it is predicted that there is no possibility of a collision between the host vehicle and the surrounding vehicle.

8. A driving assistance method executed by a vehicle, comprising: an acquisition step of acquiring surrounding vehicle information indicating a vehicle speed, a position, and a traveling trajectory of the surrounding vehicle from surrounding vehicles existing around the host vehicle through vehicle-to-vehicle communication; a prediction step of predicting a possibility of a collision between the host vehicle and the surrounding vehicle based on host vehicle information indicating a vehicle speed, a position, and a traveling trajectory of the host vehicle and the surrounding vehicle information; and a notification step of notifying an occupant of the host vehicle based on a result of the prediction step, The prediction step includes: When the surrounding vehicle is present within a first range ahead of the host vehicle, a first determination area is set using a position where the host vehicle accelerates after decelerating to a threshold value or below or a position where the host vehicle stops as a first reference position, and a possibility of a collision between the host vehicle and the surrounding vehicle in the first determination area is predicted; A driving assistance method comprising: when the surrounding vehicle is present within a second range to the side of the host vehicle, setting a second judgment area using an intersection of a predicted path of the host vehicle and a predicted path of the surrounding vehicle as a second reference position, and predicting a possibility of a collision between the host vehicle and the surrounding vehicle in the second judgment area.

9. A program for causing a computer mounted on a vehicle to execute each step of a driving assistance method, the driving assistance method comprising: an acquisition step of acquiring surrounding vehicle information indicating a vehicle speed, a position, and a traveling trajectory of the surrounding vehicle from surrounding vehicles existing around the host vehicle through vehicle-to-vehicle communication; a prediction step of predicting a possibility of a collision between the host vehicle and the surrounding vehicle based on host vehicle information indicating a vehicle speed, a position, and a traveling trajectory of the host vehicle and the surrounding vehicle information; and a notification step of notifying an occupant of the host vehicle based on a result of the prediction step, The prediction step includes: When the surrounding vehicle is present within a first range ahead of the host vehicle, a first determination area is set using a position where the host vehicle accelerates after decelerating to a threshold value or below or a position where the host vehicle stops as a first reference position, and a possibility of a collision between the host vehicle and the surrounding vehicle in the first determination area is predicted; When the surrounding vehicle is present within a second range to the side of the host vehicle, a second judgment area is set by using an intersection of the predicted path of the host vehicle and the predicted path of the surrounding vehicle as a second reference position, and a program is provided which predicts the possibility of a collision between the host vehicle and the surrounding vehicle in the second judgment area.

Images