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: a storage section that stores risk location information indicating a location where a self-vehicle on which the driving assistance device is mounted may collide with another vehicle; an assistance section that performs driving assistance for the self-vehicle on the basis of the risk location information; an acquisition section that acquires surrounding vehicle information through vehicle-to-vehicle communication from a surrounding vehicle present around the self-vehicle; an identification section that identifies an intersection point between a traveling trajectory of the self-vehicle and a traveling trajectory of the surrounding vehicle; and an update section that updates the risk location information on the basis of the intersection point identified by intersection point identification operation. The identification section executes, in a case where the surrounding vehicle is present within a first range in front of the self-vehicle, the intersection point identification operation 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 executes, in a case where the surrounding vehicle is present within a second range on a side of the self-vehicle, the intersection point identification operation using an intersection point between a predicted course of the self-vehicle and a predicted course of the surrounding vehicle as a second reference location.SELECTED DRAWING: Figure 9

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 become more active. To achieve this, efforts are being made to further improve traffic safety and convenience through research and development of preventive safety technologies. Devices that provide driving assistance to prevent collisions with other vehicles (surrounding vehicles) without using map information are known. Patent Document 1 discloses a driving assistance device that registers in a memory unit position information of an intersection where the driving trajectory of the vehicle and the driving trajectory of another vehicle intersect, and provides driving assistance to the vehicle when passing through the intersection again. Patent Document 2 discloses a technology that generates intersection feature data that indicates the characteristics of an intersection using driving trajectory data outside the intersection. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 7054636 [Patent Document 2] Japanese Patent Application Publication No. 2019-105684 Summary of the Invention [Problem to be solved by the invention]

[0004] A driving assistance device may identify a risk location where the host vehicle may collide with another vehicle based on the driving trajectory of the host vehicle and the driving trajectory of another vehicle, and use the risk location for driving assistance. However, in preventive safety technology, if an intersection location is not appropriately identified, for example, by excessively identifying risk locations for locations where the need for driving assistance is relatively low, or by not identifying risk locations for locations where the need for driving assistance is relatively high, it may be difficult to appropriately provide driving assistance. Some aspects of the present disclosure aim to provide an advantageous technology for appropriately providing driving assistance for the host vehicle, which in turn contributes to the development of a sustainable transportation system. [Means for solving the problem]

[0005] According to some embodiments, a driving assistance device includes: a storage means for storing risk position information indicating a position where a host vehicle equipped with the driving assistance device may collide with another vehicle; an assistance means for providing driving assistance for the host vehicle based on the risk position information; an acquisition means for acquiring, from nearby vehicles present around the host vehicle by vehicle-to-vehicle communication, nearby vehicle information indicating a vehicle speed, a position, and a traveling trajectory of the nearby vehicle; an identification means for performing an intersection identification operation for identifying an intersection between the traveling trajectory of the host vehicle and the traveling trajectory of the nearby vehicle; and an update means for updating the risk position information based on the intersection identified by the intersection identification operation, wherein, when the nearby vehicle is present within a first range ahead of the host vehicle, the identification means uses a position where the host vehicle accelerates after decelerating to or below a threshold value or a position where the host vehicle stops, as a first reference position. a first determination area including the surrounding vehicle and the host vehicle, and when both the surrounding vehicle and the host vehicle pass through the first determination area, The intersection specifying operation is performed, and when the peripheral vehicle is present within a second range to the side of the host vehicle, an intersection between the predicted path of the host vehicle and the predicted path of the peripheral vehicle is set as a second reference position. a second determination area including the surrounding vehicle and the host vehicle, and when both the surrounding vehicle and the host vehicle pass through the second determination area, A driving assistance device is provided that performs the intersection identification operation. [Effects of the Invention]

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

[0007] [Figure 1] FIG. 1 is a block diagram illustrating an example configuration of a vehicle according to some embodiments. [Figure 2] FIG. 10 illustrates an example of risk location information according to some embodiments. [Figure 3] 10A and 10B are schematic diagrams illustrating examples of trajectory intersections according to some embodiments. [Figure 4] 1 is a schematic diagram illustrating an example of a driving assistance method according to some embodiments. [Figure 5] 1 is a schematic diagram illustrating the presence or absence of risk locations within a target region according to some embodiments. [Figure 6] FIG. 1 is a flow diagram illustrating an example of a method for registering nearby vehicles according to some embodiments. [Figure 7] FIG. 4 is a schematic diagram illustrating an example of a range in which a nearby vehicle is detected, according to some embodiments. [Figure 8] FIG. 10 is a flow diagram illustrating an example of an intersection identification operation for a nearby vehicle ahead according to some embodiments. [Figure 9] 10A and 10B are schematic diagrams illustrating an example of an intersection identification operation for a nearby vehicle ahead according to some embodiments. [Figure 10] FIG. 10 is a flow diagram illustrating an example of an intersection identification operation for a nearby vehicle to the side, according to some embodiments. [Figure 11] 10A and 10B are schematic diagrams illustrating an example of an intersection identification operation regarding a nearby vehicle to the side according to some embodiments. [Figure 12] 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 INVENTION

[0008] Hereinafter, the embodiments will be described in detail with reference to the accompanying drawings. Note that the following embodiments do not limit the scope of the invention as claimed, and not all combinations of features described in the embodiments are necessarily essential to the invention. Two or more of the features described in the embodiments may be combined in any desired manner. Furthermore, the same reference numerals are used to designate identical or similar components, and redundant descriptions will be omitted.

[0009] <Vehicle configuration example> With reference to FIG. 1 , an example configuration 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. Although FIG. 1 illustrates the components referred to in the following description, the vehicle 100 may include other components for operating as a vehicle, such as a drive unit, a transmission, and lighting equipment. Additionally or alternatively, 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 will be described later, the control device 106 performs driving assistance for the vehicle 100 in which the control device 106 is installed. Therefore, the control device 106 may be referred to as 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 is capable of performing collision prevention assistance without using map information. In the following description, the vehicle 100 may be referred to as the host vehicle 100 to easily distinguish it from other vehicles. Furthermore, a vehicle different from the vehicle 100 may be referred to as another vehicle. Of the other vehicles, a vehicle currently present around the host vehicle 100 may be referred to as a surrounding vehicle. A 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, etc. The sensor group 101 may also include external detection sensors such as a camera, millimeter wave radar, and LIDAR (Light Detection and Ranging) 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 acquire information about the current position and / or driving path (driving history) of the vehicle 100. The vehicle-to-vehicle communication antenna 103 is an antenna that transmits and receives various data to and from surrounding vehicles. For example, the vehicle-to-vehicle communication antenna 103 can be used to acquire information about the current position, speed, and driving path of surrounding vehicles.

[0013] The notification device 104 is a device that issues a notification to an occupant (e.g., a driver) of the vehicle 100. When there is a possibility that the vehicle 100 will collide with a nearby vehicle, the control device 106 can notify the occupant of the vehicle 100 of the possibility of a collision with the nearby vehicle by using 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 nearby 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 nearby 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 on the vehicle 100. When there is a possibility that the vehicle 100 will collide with a nearby vehicle, the control device 106 operates the braking device 105 to assist in deceleration of the vehicle 100 as driving assistance, thereby making it possible to avoid a collision with the nearby vehicle.

[0015] The control device 106 is a device (computer) that controls the vehicle 100, and may be configured, for example, by an ECU (Electric Control Unit). The control device 106 can perform driving assistance through inter-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 an inter-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 programs 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, etc., and stores a program (driving assistance program) for the processing unit 110 to execute driving assistance processing for the vehicle 100, a program (learning program) for the processing unit 110 to learn risk locations, various data, etc. The storage unit 111 may store risk location information 112 created based on intersections between the driving trajectory of the vehicle 100 and the driving trajectory of another vehicle. The risk location information 112 may include multiple risk locations. A risk location may be a location where there is a possibility or a high probability that the vehicle 100 will collide with another vehicle. The risk location information 112 may be managed as a database.

[0017] The GNSS module 113 receives position information and the like of the vehicle 100 from GNSS satellites via the GNSS antenna 102. 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 support unit 110b, an identification unit 110c, and an update unit 110d in order to perform 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 to be performed in the vehicle 100.

[0019] The acquisition unit 110a acquires surrounding vehicle information indicating the current position, vehicle speed, and traveling trajectory of a surrounding vehicle from a surrounding vehicle present around the vehicle 100 via the inter-vehicle communication antenna 103 (inter-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 is, or may include information for calculating the vehicle speed (two geographical positions, one current and one immediately preceding, and the times at which they were measured). 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 support unit 110b predicts the possibility of the vehicle 100 colliding with another vehicle within a target area ahead of the vehicle 100 based on the host vehicle information and surrounding vehicle information acquired by the acquisition unit 110a, and controls driving support (collision prevention support) for the vehicle 100 based on the prediction result. The target area may be understood as an area (driving support area) for which driving support is provided to prevent a collision between the vehicle 100 and another vehicle, and may be simply referred to as a "target area" hereinafter. In some embodiments, the support unit 110b may perform at least one of the following as driving support for the vehicle 100: notifying the occupants of the vehicle 100 by the alarm device 104 and assisting the deceleration of the vehicle 100 by the braking device 105.

[0021] Furthermore, the support unit 110b may provide driving support for the vehicle 100 based on the risk location information 112. For example, the support unit 110b may change the degree of driving support (collision prevention support) for the vehicle 100 depending on whether or not at least one risk location among the multiple risk locations included in the risk location information 112 is present within the target area.

[0022] For example, when at least one risk position exists within the target area, the assistance unit 110b increases the degree of driving assistance for the vehicle 100 compared to when no risk position exists within the target area. Examples of increasing the degree of driving assistance for the vehicle 100 include relaxing the operating conditions of the driving assistance so that the driving assistance is more likely to be activated, increasing the notification level of the notification device 104, and increasing the deceleration of the vehicle 100 by the braking device 105. Examples of relaxing the operating conditions of the driving assistance include increasing the time threshold for activating the driving assistance with respect to the time to collision (TTC: Time To Collision) calculated as the possibility of collision of the vehicle 100.

[0023] The identification unit 110c identifies an intersection between the travel trajectory of the vehicle 100 and the travel trajectories of the surrounding vehicles. The operation of identifying an intersection between the travel trajectory of the vehicle 100 and the travel trajectories of the surrounding vehicles will be referred to as an intersection identification operation below. An intersection between the travel trajectory of the vehicle 100 and the travel trajectories of the surrounding vehicles will be referred to as a trajectory intersection below. There is a possibility that a road intersection exists near the trajectory intersection. The conditions for starting the intersection identification operation and the details of the intersection identification operation will be described later.

[0024] The update unit 110d updates the risk location information 112 stored in the storage unit 111 based on the trajectory intersection identified by the intersection identifying operation. 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.

[0025] 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 other formats. 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.

[0026] The risk location information 112 may include, for each risk location, information regarding a risk location ID, registration date and time, coordinates, and passing direction. 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 was 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 elevation 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 (approach direction) of the vehicle 100 when entering the trajectory intersection. In the example of FIG. 2, the passing direction of the vehicle 100 is defined as 0° north, 90° east, 180° south, and 270° west.

[0027] 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 will be described in which 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 left side of the vehicle 100. The embodiments described in this specification are also applicable to a case in which 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.

[0028] In the example shown in FIG. 3(a), the position where the travel trajectory 301a of the host vehicle 100 traveling straight north and the travel trajectory 302a of the other vehicle OVa traveling straight west intersects is the trajectory intersection CPa. Note that the timing (time) at which the host vehicle 100 passes through the trajectory intersection CPa is different from the timing (time) at which the other vehicle OVa passes through the trajectory intersection CPa, so no collision occurs between the host vehicle 100 and the other vehicle OVa. Furthermore, the travel 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 travel 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 is a nearby vehicle present around the host vehicle 100 at the time of acquisition, the other vehicle information may be understood as nearby vehicle information.

[0029] 3(b), the position where a travel trajectory 301b of the host vehicle 100, which travels straight north and turns left, intersects with a travel trajectory 302b of another vehicle OVb, which travels straight south, is the trajectory intersection CPb. Note that the timing (time) at which the host vehicle 100 passes through the trajectory intersection CPb is different from the timing (time) at which the other vehicle OVb passes through the trajectory intersection CPb, so no collision occurs between the host vehicle 100 and the other vehicle OVb. Furthermore, the travel trajectory 301b of the host vehicle 100, like the travel trajectory 301a, 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).

[0030] 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 programmable logic device (PLD) or an application specific integrated circuit (ASIC). In addition, although the control device 106 is shown as a single element in the example of FIG. 1, it may be divided into two or more elements as necessary.

[0031] <Driving assistance processing> The driving assistance process of some embodiments will be described with reference to Figures 4 and 5. The driving assistance process shown in the flowchart of Figure 4 may be performed by the processing unit 110 of the control device 106 executing a driving assistance program read from the storage unit 111. The process of Figure 4 may be started, for example, in response to the driving assistance setting being turned on. The process of Figure 4 may be repeatedly executed until the driving assistance setting is turned off or until the ignition of the vehicle 100 is turned off.

[0032] In step S401, the processing unit 110 (for example, the support unit 110b) determines whether or not a risk position RP exists within the target area TA ahead of the vehicle 100 by referring to the risk position information 112 stored in the memory unit 111. For example, the processing unit 110 can determine whether or not a risk position RP exists within the target area TA by comparing the current position of the vehicle 100 acquired by the acquisition unit 110a via the GNSS antenna 102 (GNSS module 113) with the coordinates (latitude, longitude) of each risk position RP included in the risk position information 112. FIG. 5(a) shows an example in which no risk position RP exists within the target area TA ahead of the vehicle 100, and FIG. 5(b) shows an example in which a risk position RP exists within the target area TA ahead of the vehicle 100.

[0033] The processing unit 110 transitions the process to step S402 when there is no risk position RP within the target area TA. The processing unit 110 (for example, its support unit 110b) sets the driving support intensity, which is the degree of driving support, to a low level. On the other hand, when there is a risk position RP within the target area TA, the processing unit 110 transitions the process to step S403. The processing unit 110 (for example, its support unit 110b) sets the driving support intensity to a high level. The high level is set so that the degree of driving support (driving support intensity) is greater than that of the low level. For example, when the driving support intensity is at a high level, the activation conditions for driving support may be relaxed compared to when the driving support intensity is at a low level. In other words, when the driving support intensity is at a high level, driving support may be more likely to occur than when the driving support intensity is at a low level. For example, even in a situation where driving assistance is not performed when the driving assistance intensity is low (for example, when the vehicle 100 is in a specific driving state, when the vehicle 100 is traveling on a specific road, etc.), driving assistance may be performed when the driving assistance intensity is high. Note that, although the present embodiment illustrates two types of driving assistance intensity, low and high, the number of driving assistance levels is not limited to two, and may be three or more.

[0034] In step S404, the processing unit 110 determines whether or not there is a surrounding vehicle RV. As described above, a surrounding vehicle RV is a vehicle that is currently present around the vehicle 100. For example, the processing unit 110 can determine that there is a surrounding vehicle RV when vehicle-to-vehicle communication can be performed via the vehicle-to-vehicle communication antenna 103 (vehicle-to-vehicle communication module 114). If the processing unit 110 determines that there is no surrounding vehicle RV, it transitions the process to step S401, and if the processing unit 110 determines that there is a surrounding vehicle RV, it transitions the process to step S405.

[0035] In step S405, the processing unit 110 (acquisition unit 110a) acquires host vehicle information and surrounding vehicle information. For example, the processing unit 110 acquires surrounding vehicle information including the current position, speed, and traveling trajectory of the surrounding vehicle RV from the surrounding vehicle RV via the inter-vehicle communication antenna 103 (inter-vehicle communication module 114). In addition, the processing unit 110 acquires host vehicle information including the current position, speed, and traveling trajectory of the vehicle 100 via the sensor group 101 and the GNSS antenna 102 (GNSS module 113).

[0036] In step S406, the processing unit 110 (for example, the support unit 110b) predicts the possibility of a collision between the vehicle 100 and the surrounding vehicle RV within the target area TA based on the host vehicle information and the surrounding vehicle information acquired in step S405. Thereafter, in step S407, the processing unit 110 (for example, the support unit 110b) determines whether or not there is a possibility of a collision between the vehicle 100 and the surrounding vehicle RV based on the prediction result in step S406. If the processing unit 110 determines that there is no possibility of a collision, it transitions the processing to step S401, and if it determines that there is a possibility of a collision, it transitions the processing to step S408.

[0037] In step S408, the processing unit 110 (for example, the support unit 110b) determines whether the speed of the surrounding vehicle RV is within a specified range based on the surrounding vehicle information acquired in step S405. The specified range may be set in advance by a lower limit speed value and an upper limit speed value for the speed of the surrounding vehicle RV. If the speed of the surrounding vehicle RV is equal to or less than the lower limit speed value of the specified range, the driver of the surrounding vehicle RV is likely to notice the vehicle 100 and slow down the surrounding vehicle RV without colliding with the vehicle 100. In other words, the lower limit speed value of the specified range for the speed of the surrounding vehicle RV may be set to a value that allows the surrounding vehicle RV to slow down without colliding with the vehicle 100. Furthermore, if the speed of the surrounding vehicle RV is equal to or greater than the upper limit speed value of the specified range, the surrounding vehicle RV is likely not a vehicle traveling on the road into which the vehicle 100 is entering, such as traveling on a highway near the road into which the vehicle 100 is entering. That is, the upper limit of the specified range for the speed of the nearby vehicle RV can be set to a value that makes it possible to distinguish whether the nearby vehicle RV is traveling on the road into which the vehicle 100 is entering or a vehicle traveling on an expressway near the road. In this way, by performing / suppressing driving assistance depending on whether the speed of the nearby vehicle RV is within the specified range, it is possible to reduce the annoyance felt by the driver of the vehicle 100 due to the driving assistance.

[0038] If the processing unit 110 determines in step S408 that the speed of the nearby vehicle RV is not within a specified range, i.e., is outside the specified range, the processing unit 110 transitions the process to step S401. That is, in the case of the method of FIG. 4, the processing unit 110 does not provide driving assistance for the vehicle 100 if the speed of the nearby vehicle RV is outside the specified range, regardless of the collision possibility predicted in steps S406 and S407. On the other hand, if the processing unit 110 determines that the speed of the nearby vehicle RV is within the specified range, the processing unit 110 transitions the process to step S409. In step S409, the processing unit 110 (driving assistance unit 21c) provides driving assistance for the vehicle 100. As driving assistance for the vehicle 100, the processing unit 110 can notify the occupants of the vehicle 100 of the possibility of a collision using the alarm device 104, or can perform a braking operation for the vehicle 100 using the braking device 105.

[0039] In this way, the control device 106 changes the degree of driving assistance (driving assistance intensity) for the vehicle 100 depending on whether or not the risk position RP exists in the target area TA ahead of the vehicle 100.

[0040] <Risk location learning process> The risk location learning process will be described with reference to Figs. 6 to 11. Fig. 6 describes an example of a process for managing surrounding vehicles. The process shown in the flowchart of Fig. 6 is executed by the processing unit 110 in parallel with the flowchart of Fig. 4 according to a learning program read from the storage unit 111. The process of Fig. 6 may be started, for example, when the ignition of the vehicle 100 is turned on. The process of Fig. 6 can be repeatedly executed until the ignition of the vehicle 100 is turned off.

[0041] In step S601, the processing unit 110 (for example, 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 S602, and otherwise transitions the process to step S604. 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), similar to step S404 in FIG. 4.

[0042] In step S602, the processing unit 110 (for example, the acquisition unit 110a) registers the other vehicle discovered in step S601 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 discovered nearby vehicle to this list. As will be described later, the nearby vehicle is used as a target of the intersection identification operation.

[0043] In step S603, the processing unit 110 (for example, the acquisition unit 110a) starts acquiring surrounding vehicle information from surrounding vehicles through vehicle-to-vehicle communication. As described above, the surrounding vehicle information may represent the vehicle speed, position, and travel trajectory of the surrounding vehicles. After starting to acquire surrounding vehicle information in step S602, the processing unit 110 repeatedly acquires surrounding vehicle information periodically (for example, every 100 ms) until vehicle-to-vehicle communication with the surrounding vehicles becomes impossible.

[0044] After starting to acquire the surrounding vehicle information, in step S603, the processing unit 110 (for example, the acquisition unit 110a) determines whether there is one or more registered surrounding vehicles that are no longer able to perform inter-vehicle communication. If such a vehicle is present, the processing unit 110 transitions the process to step S605, and otherwise transitions the process to step S601. For example, if a surrounding vehicle moves 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.

[0045] In step S605, the processing unit 110 (for example, 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.

[0046] As described above, by executing the process of FIG. 6, the processing unit 110 can periodically acquire the latest nearby vehicle information from other vehicles in the vicinity of the vehicle 100 (that is, nearby vehicles).

[0047] Next, a method for learning a risk position using the peripheral vehicle information acquired in this manner will be described. As described with reference to FIG. 3(a), when another vehicle is included in the range to the side of the host vehicle 100, if the host vehicle 100 and the other vehicle both travel 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 ahead 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 travels 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 learns the risk position differently depending on whether the peripheral vehicle is present in the range ahead of the host vehicle 100 or in the range to the side of the host vehicle 100.

[0048] With reference to FIG. 7, a range for selecting a risk location learning method will be described. Range 700 is located ahead of vehicle 100. The range ahead of vehicle 100 may refer to a range that includes the front of vehicle 100. Range 700 may be a sector-shaped region as shown in FIG. 7, or may have another shape. Range 700 may be symmetrical with respect to the direction ahead of vehicle 100. The central angle of range 700 may be, for example, approximately 100 degrees to 110 degrees. Range 701 is located to the side of vehicle 100. The side of vehicle 100 may refer to a range that includes the diagonally forward direction of vehicle 100. Range 701 may include a direction directly to the side of vehicle 100. Range 701 may be a sector-shaped region as shown in FIG. 7, or may have another shape. In the example of FIG. 7, ranges 701 are located on both the right and left sides of vehicle 100. The central angle of range 701 may be, for example, approximately 80 degrees to 90 degrees. In the example of FIG. 7, a portion of range 700 and a portion of range 701 overlap. The central angle of this overlapping portion may be, for example, approximately 10 to 20 degrees. When a nearby vehicle is present in this overlapping portion, this nearby vehicle becomes the target of both an intersection point identification operation (described below) for identifying trajectory intersection CPa in FIG. 3(a) and an intersection point identification operation (described below) for identifying trajectory intersection CPb in FIG. 3(b). As an alternative to the example of FIG. 7, range 700 and range 701 may simply touch each other, or may be separated from each other.

[0049] When a nearby vehicle is included in the range 701, the control device 106 may generate a trajectory intersection CPa by the host vehicle 100 traveling straight, as shown in FIG. 3(a). Therefore, the control device 106 performs an intersection specifying operation so as to appropriately specify the trajectory intersection CPa. This operation will be described later with reference to FIGS. 8 and 9. On the other hand, when a nearby vehicle is included in the range 700, the control device 106 may generate a trajectory intersection CPb by the host vehicle 100 turning left, as shown in FIG. 3(b). Therefore, the control device 106 performs an intersection specifying operation so as to appropriately specify the trajectory intersection CPb. This operation will be described later with reference to FIGS. 10 and 11. The positions of the ranges 700 and 701 relative to the host 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.

[0050] FIG. 8 illustrates an example of processing for performing an intersection identification operation when a nearby vehicle RV (FIG. 9(a)) is present within a range 701 to the side of the host vehicle 100. The processing shown in the flowchart of FIG. 8 is executed by the processing unit 110 in accordance with a learning program read from the storage unit 111. The processing of FIG. 8 may be executed for a nearby vehicle RV, for example, each time a new nearby vehicle RV is registered in step S602 of FIG. 6. In the processing of FIG. 6, multiple other vehicles may be registered as nearby vehicles. The processing of FIG. 8 is executed for each of these multiple nearby vehicles.

[0051] In step S801, the processing unit 110 (for example, the identification unit 110c thereof) determines whether the surrounding vehicle RV is present within the range 701 to the side of the host vehicle 100. If it is determined that the surrounding vehicle RV is present within the range 701 to the side of the host vehicle 100, the processing unit 110 transitions the processing to step S802, and otherwise repeats step S801. 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. 9(a), the surrounding vehicle RV is present within the range 701.

[0052] In step S802, the processing unit 110 (for example, the identification unit 110c thereof) determines whether the predicted path of the host vehicle 100 and the predicted path of the peripheral vehicle RV intersect. If it is determined that these predicted paths intersect, the processing unit 110 transitions the process to step S803, and otherwise repeats step S802. The predicted path may be a half line extending forward from the vehicle. In the example shown in FIG. 9(a), the predicted path 900 of the host vehicle 100 intersects with the predicted path 901 of the peripheral vehicle RV. The intersection of the predicted path 900 of the host vehicle 100 and the predicted path 901 of the peripheral vehicle RV is represented as a predicted intersection 902. The predicted path 900 of the host vehicle 100 may be determined based on host vehicle information (specifically, the current position and traveling trajectory). The processing unit 110 may acquire the latest host vehicle information at this point. The predicted course 901 of the nearby vehicle RV may be determined based on the latest nearby vehicle information (specifically, the current position and travel path).

[0053] In step S803, the processing unit 110 (for example, the identification unit 110c thereof) sets a determination area using the predicted intersection 902 as a reference position, and stores the reference position and the determination area in the storage unit 111. The determination area may be an area used to determine the start of execution of an intersection identification operation, which will be described later. With reference to FIG. 9(a), an example of the determination area 903 set using the predicted intersection 902 as a reference position will be described. The determination area 903 may be a square centered on the predicted intersection 902 and including sides parallel to the predicted path 900 of the vehicle 100. One side of this square may have a length equivalent to, for example, three lanes (for example, approximately 9 m to 11 m). The determination area 903 is a planar area that includes the predicted intersection 902. Alternatively, the determination area 903 may have another shape.

[0054] In the example of FIG. 9(a), the determination area 903 is a planar area. Alternatively, as shown in FIG. 9(b), the determination area 903 may be a linear area. In the example of FIG. 9(b), the determination area 903 is an L-shaped area formed by a side far from the vehicle 100 and a side on the oncoming lane side (the left side in this example) of a square centered on the predicted intersection 902 and including sides parallel to the predicted path 900 of the vehicle 100. The position of the determination area 903 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.

[0055] In step S806, the processing unit 110 (for example, the identification unit 110c thereof) determines whether both the surrounding vehicle RV that is the target of the processing in FIG. 8 and the host vehicle 100 have passed through the determination area 903. If it is determined that both the surrounding vehicle RV and the host vehicle 100 have passed through the determination area 903, the processing unit 110 transitions the processing to step S808, and otherwise transitions the processing to step S807. This determination may be made based on the latest host vehicle information (specifically, the current position and traveling trajectory) and the latest surrounding vehicle information (specifically, the current position and traveling trajectory). Passing through the determination area 903 may mean that the current position of the vehicle has a common portion with the determination area 903 and then no longer has a common portion with the determination area 903.

[0056] In step S808, the processing unit 110 (for example, the identification unit 110c thereof) executes an intersection identifying operation. Specifically, the processing unit 110 identifies an intersection (i.e., a trajectory intersection) between the travel trajectory of the host vehicle 100 after the determination area is set in step S803 and the travel trajectory of the peripheral vehicle RV. The intersection identifying operation may be performed based on the latest host vehicle information and the latest peripheral vehicle information. In this manner, the intersection identifying operation is performed based on the determination area set with the predicted intersection 902 as the reference position. Therefore, the intersection identifying operation can be considered to be performed with the predicted intersection 902 as the reference position. In step S808, there may be no intersection between the travel trajectory of the host vehicle 100 and the travel trajectory of the peripheral vehicle RV. In this case, even if the intersection identifying operation is performed, a trajectory intersection is not identified.

[0057] In step S809, the processing unit 110 (e.g., its update unit 110d) updates the risk location information 112 based on the trajectory intersection identified by the intersection identifying operation in step S808. For example, if the risk location information 112 does not include a risk location near (e.g., within 20 m) a trajectory intersection, the processing unit 110 may include the trajectory intersection as a new risk location in the risk location information 112. If the risk location information 112 includes a risk location near (e.g., within 20 m) a trajectory intersection, the processing unit 110 may correct the risk location based on the trajectory intersection. This correction may be, for example, a weighted average of the risk location and the trajectory intersection. The weight of the risk location may be the number of trajectory intersections used to determine the risk location. When updating the risk location information 112, the processing unit 110 also registers information in each column shown in FIG. 2. If a trajectory intersection is not identified by the intersection identification operation (i.e., if the travel trajectory of the host vehicle 100 and the travel trajectory of the surrounding vehicle RV do not intersect), step S809 is skipped (the risk position information 112 is not updated).

[0058] In step S810, the processing unit 110 (for example, the identification unit 110c) deletes the reference position and determination area (the reference position and determination area stored in step S803) that have become unnecessary since the intersection identification operation has ended from the storage unit 111. This prevents the capacity of the storage unit 111 from being consumed by unnecessary information.

[0059] If it is determined in step S806 that at least one of the surrounding vehicle RV and the host vehicle 100 has not passed through the judgment area 903, step S807 is executed. In step S807, the processing unit 110 (for example, its identification unit 110c) determines whether the host vehicle 100 has moved a predetermined distance (for example, 30 m) or more from the reference position stored in step S803. 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 S810; otherwise, the processing unit 110 transitions the processing to step S804. If the host vehicle 100 has moved a predetermined distance or more from the reference position before both the surrounding vehicle RV and the host vehicle 100 have passed through the judgment area 903, there is a possibility that, for example, the surrounding vehicle RV or the host vehicle 100 has turned around without passing through the judgment area 903. Therefore, the processing unit 110 ends the processing without performing the intersection identification operation. In this case as well, in step S810, the processing unit 110 (for example, the specifying unit 110c thereof) deletes from the storage unit 111 the reference position and determination region that are no longer needed.

[0060] If it is determined in step S807 that the host vehicle 100 is not away from the reference position by a predetermined distance or more, step S804 is executed. In step S804, the processing unit 110 (e.g., its identification unit 110c) redetermines the predicted intersection 902 and determines whether its position has changed. If it is determined that the position of the predicted intersection 902 has changed, the processing unit 110 transitions the process to step S805; otherwise, the processing unit 110 transitions the process to step S806. For example, the position of the predicted intersection 902 may change if the vehicle (host vehicle 100 or surrounding vehicle RV) changes its position within a lane or changes lanes. Because surrounding vehicle information is repeatedly acquired, the processing unit 110 can detect such a change in the position of the predicted intersection 902. Therefore, in step S805, the processing unit 110 (e.g., its identification unit 110c) updates the reference position stored in the storage unit 111 based on the newly acquired surrounding vehicle information, and accordingly updates the determination area stored in the storage unit 111. As a result, the determination in step S806 is made based on the updated determination area. Also, the determination in step S807 is made based on the updated reference position. If the predicted intersection 902 cannot be re-determined in step S804 (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 determination area are maintained.

[0061] In the method of Fig. 8, unless it is determined in step S801 that a nearby vehicle is present within range 701, it is determined in step S802 that the predicted path of the nearby vehicle and the predicted path of vehicle 100 intersect, and it is determined in step S806 that these vehicles have passed through the determination area, the intersection identification operation of step S808 is not executed. This makes it possible to prevent the risk position information from being inappropriately updated. When the registration of the nearby vehicle that is the target of the processing of Fig. 8 is canceled in step S605 of Fig. 6, the processing unit 110 may cancel the processing of Fig. 8.

[0062] According to the method of Fig. 8, when multiple peripheral vehicles are present within range 701 to the side of host vehicle 100, an individual reference position is used for each of the multiple peripheral vehicles. Specifically, the method of Fig. 8 is executed individually for each of the multiple peripheral vehicles. As a result, a predicted intersection between the predicted path of host vehicle 100 and the predicted paths of the peripheral vehicles is also determined for each of the multiple peripheral vehicles. As a result, an individual determination area is set for each of the multiple peripheral vehicles based on the individual reference position. This makes it possible to appropriately estimate the position of an intersection where multiple lanes intersect, etc.

[0063] FIG. 10 illustrates an example of processing for performing an intersection identification operation when a nearby vehicle RV (FIG. 11(a)) is present within a range 700 ahead of the host vehicle 100. The processing shown in the flowchart of FIG. 10 is executed by the processing unit 110 in accordance with a learning program read from the storage unit 111. The processing of FIG. 10 may be started, for example, when the ignition of the vehicle 100 is turned on. The processing of FIG. 10 may be repeatedly executed until the ignition of the vehicle 100 is turned off.

[0064] In step S1001, the processing unit 110 (e.g., its identification unit 110c) determines whether the host vehicle 100 accelerated or stopped temporarily after decelerating to a threshold value or below. If it is determined that the host vehicle 100 accelerated or stopped temporarily after decelerating to a threshold value or below, the processing unit 110 transitions the process to step S1002; otherwise, the processing unit 110 repeats step S1001. This determination 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 S1001 is a value below which the vehicle speed after decelerating to turn (e.g., turn left or turn right) falls, and may be, for example, 20 km / h. The position where the host vehicle 100 accelerated or stopped temporarily after decelerating to a threshold value or below is represented as a turning preparation position 1101 ( FIG. 11(a) ). Note that the host vehicle 100 may accelerate or stop temporarily after decelerating to a threshold value or below even if it does not turn. Even in this case, the processing unit 110 detects the turning preparation position 1101 and executes the processes from step S1002 onwards.

[0065] In step S1002, the processing unit 110 (for example, the identification unit 110c thereof) sets a determination area using the turning preparation position 1101 as a reference position, and stores the reference position and the determination area in the storage unit 111. The determination area may be an area used to determine the start of execution of an intersection identification operation, which will be described later. With reference to FIG. 11(a), an example of the determination area 1102 set using the turning preparation position 1101 as a reference position will be described. The determination area 1102 may be a square centered on the left front position of the turning preparation position 1101 and including sides parallel to the predicted path 900 of the host vehicle 100. One side of this square may have a length equivalent to, for example, three lanes (for example, approximately 9 m to 11 m). The determination area 1102 is a planar area. Alternatively, the determination area 1102 may have another shape. For example, the determination area 1102 may be a rectangle with a longer side parallel to the predicted path 900 of the host vehicle 100. The processing unit 110 sets a determination region 1102 so as to include a turning preparation position 1101 (i.e., a reference position) and to be offset toward the oncoming lane (to the left in the example of FIG. 11(a)) relative to the host vehicle 100 in a direction perpendicular to the predicted path 900 of the host vehicle 100. This makes it possible to appropriately identify a trajectory intersection that occurs when the host vehicle 100 turns left.

[0066] In the example of FIG. 11(a), the determination area 1102 is a planar area. Alternatively, as shown in FIG. 11(b), the determination area 1102 may be a linear area. In the example of FIG. 11(b), the determination area 1102 is a U-shaped area centered on the left front position of the turning preparation position 1101 and configured by three sides of a square including sides parallel to the predicted path 900 of the vehicle 100, excluding the side farthest from the vehicle 100. The position of the determination area 1102 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.

[0067] In step S1003, the processing unit 110 (for example, its identification unit 110c) identifies a peripheral vehicle RV present within the range 700 ahead of the host vehicle 100 as a target vehicle for subsequent processing. If no peripheral vehicle RV exists within the range 700, no target vehicle is identified. If multiple peripheral vehicles RV exist within the range 700, all of these multiple peripheral vehicles RV are identified as target vehicles. This identification may be performed based on the current positions of the peripheral vehicles RV included in the latest peripheral vehicle information acquired from the peripheral vehicles RV. In the example shown in FIG. 11(a), one peripheral vehicle RV exists within the range 700.

[0068] In step S1004, the processing unit 110 (for example, the identification unit 110c thereof) determines whether the host vehicle 100 has passed through the judgment area 1102. If it is determined that the host vehicle 100 has passed through the judgment area 1102, the processing unit 110 transitions the process to step S1006, and otherwise transitions the process to step S1005. This determination may be made based on the latest host vehicle information (specifically, the current position and traveling trajectory). Passing through the judgment area 1102 may mean that the current position of the vehicle has a common portion with the judgment area 1102 and then no longer has a common portion with the judgment area 1102.

[0069] In step S1006, the processing unit 110 (for example, the identification unit 110c thereof) executes an intersection identification operation for each of the target vehicles that have passed through the judgment area 1102 among all the target vehicles identified in S1003. Specifically, the processing unit 110 identifies an intersection (i.e., a trajectory intersection) between the traveling trajectory of the host vehicle 100 after the judgment area is set in step S1002 and the traveling trajectory of the target vehicle. The intersection identification operation may be performed based on the latest host vehicle information and the latest surrounding vehicle information. In this manner, the intersection identification operation is performed based on the judgment area that is set using the turning preparation position 1101 as a reference position. Therefore, the intersection identification operation can be considered to be performed using the turning preparation position 1101 as a reference position. In step S1006, there may be no intersection between the traveling trajectory of the host vehicle 100 and the traveling trajectory of the surrounding vehicle RV. In this case, even if the intersection identification operation is executed, a trajectory intersection is not identified.

[0070] In step S1007, the processing unit 110 (for example, the update unit 110d thereof) updates the risk position information 112 based on the trajectory intersection identified by the intersection identifying operation in step S1007. The processing in step S1007 may be the same as the processing in step S809, and therefore a redundant description will be omitted.

[0071] If there is no surrounding vehicle RV identified as a target vehicle in step S1004, or if there is no target vehicle that has passed through the determination area 1102, steps S1006 and S1007 are skipped.

[0072] The process of step S1008 may be the same as the process of step S810, so a duplicated description will be omitted.

[0073] If it is determined in step S1004 that the host vehicle 100 has not passed through the judgment area 1102, step S1005 is executed. In step S1005, the processing unit 110 (for example, its identification unit 110c) determines whether the host vehicle 100 has moved a predetermined distance (for example, 30 m) or more from the reference position (i.e., the turning preparation position 1101) stored in step S1002. 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 S1008, and otherwise transitions the processing to step S1003. If the host vehicle 100 has moved a predetermined distance or more from the reference position before passing through the judgment area 1102, there is a possibility that the host vehicle 100 has turned without passing through the judgment area 1102, for example. Therefore, the processing unit 110 ends the processing without performing the intersection identification operation. In this case as well, in step S1008, the processing unit 110 (for example, the specifying unit 110c thereof) deletes from the storage unit 111 the reference position and determination region that are no longer needed.

[0074] If it is determined in step S1005 that the host vehicle 100 is not further away from the reference position by a predetermined distance or more, step S1003 is executed again. In step S1003, the processing unit 110 (for example, the identification unit 110c) identifies the nearby vehicle RV that is now newly included in the range 700 as a target vehicle for subsequent processing. Even if a new nearby vehicle is present in the range 700, the processing unit 110 does not execute step S1002 (i.e., does not set a new determination area 1102) until the determination area 1102 is set in step S1002 and deleted in step S1008.

[0075] 10, the intersection identification operation in step S1006 is not executed unless it is determined in step S1001 that the host vehicle 100 has accelerated again or stopped temporarily, and it is determined in step S1004 that the host vehicle 100 and the surrounding vehicles RV present within the range 700 have passed through the determination area. This makes it possible to prevent the risk position information from being inappropriately updated.

[0076] 10, when multiple peripheral vehicles are present within the range 700 ahead of the host vehicle 100, a common reference position (i.e., turning preparation position 1101) is used for the multiple peripheral vehicles. As a result, a common determination area is set for each of the multiple peripheral vehicles based on the common reference position. This allows the position of the intersection when the host vehicle 100 turns to the oncoming lane (for example, when turning left) to be appropriately estimated.

[0077] In the above-described driving assistance method, a surrounding vehicle RV is set as a target for learning a risk position based on whether the surrounding vehicle RV is located within range 700 or 701 in Fig. 7. The processing unit 110 may determine whether to set the surrounding vehicle RV as a target for learning a risk position based on other information. An example of a method for determining a surrounding vehicle RV as a target for learning a risk position will be described with reference to Fig. 12.

[0078] The processing unit 110 may determine whether to include the nearby vehicle RV in risk position learning based on a rotation angle 1203 of the path vector 1202 of the nearby vehicle RV relative to the path vector 1201 of the host vehicle 100. The path vector 1201 may be a unit vector facing the vehicle's traveling direction. For the sake of explanation, the clockwise direction of the rotation angle 1203 is defined as positive and the counterclockwise direction as negative. The processing unit 110 can determine the approach direction of the nearby vehicle RV based on the direction of the nearby vehicle RV relative to the host vehicle 100 and the rotation angle 1203 of the path vector 1202 of the nearby vehicle RV relative to the path vector 1201 of the host vehicle 100.

[0079] Even if the surrounding vehicle RV is included in the range 700 ahead 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 treat the surrounding vehicle RV as a target for learning the risk position in the processing of Fig. 4 when the surrounding vehicle RV is within the range 700 ahead of the host vehicle 100 and the rotation angle 1203 is included in a predetermined range (for example, 160° to 200°).

[0080] Even if the surrounding vehicle RV is included in the range 701 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 if the surrounding vehicle RV is 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 treat the surrounding vehicle RV as a target for learning a risk position in the processing of Fig. 4 when the surrounding vehicle RV is included in the range 701 on the right side of the host vehicle 100 and the rotation angle 1203 is included in a predetermined range (for example, -110° to -70°).

[0081] Even if the nearby vehicle RV is included in the range 701 on the left side of the host vehicle 100, if the nearby vehicle RV is traveling in the same direction as the host vehicle 100 or in the opposite direction, or if the nearby vehicle RV is 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 nearby vehicle RV. Therefore, the processing unit 110 may treat the nearby vehicle RV as a target for learning a risk position in the processing of Fig. 4 when the nearby vehicle RV is included in the range 701 on the left side of the host vehicle 100 and the rotation angle 1203 is included in a predetermined range (for example, 70° to 110°).

[0082] According to the above-described embodiment, an appropriate intersection identification operation is performed depending on the positions of the surrounding vehicles, so that risk position information can be determined with high accuracy. As a result, driving assistance for the host vehicle 100 can be performed appropriately.

[0083] <Summary of the embodiment> [Item 1] A driving assistance device (106), A storage means (111) for storing risk position information (112) representing a position where a vehicle (100) equipped with the driving assistance device may collide with another vehicle (RV); an assistance means (110b) for providing driving assistance to the host vehicle based on the risk position information; an acquisition means (111a) for acquiring, from a surrounding vehicle present around the host vehicle, surrounding vehicle information indicating a vehicle speed, a position, and a traveling path of the surrounding vehicle by vehicle-to-vehicle communication; Identification means (110c) for executing an intersection identification operation for identifying intersections (CPa, CPb) between the travel path of the host vehicle and the travel path of the surrounding vehicle; and an update means (110d) for updating the risk location information based on the intersections identified by the intersection identifying operation, The identification means When the surrounding vehicle is present within a first range (700) ahead of the host vehicle, the intersection specifying operation is performed using a position where the host vehicle has accelerated after decelerating to a threshold value or less or a position where the host vehicle has stopped temporarily as a first reference position (1101); A driving assistance device that, when the surrounding vehicle is present within a second range (701) to the side of the vehicle, executes the intersection point identification operation using the intersection point between the predicted path (900) of the vehicle and the predicted path (901) of the surrounding vehicle as a second reference position (902). According to this item, risk location information can be updated appropriately, and as a result, driving assistance can be provided appropriately. [Item 2] The identification means When a plurality of peripheral vehicles are present within the first range, the first reference position is used in common for the plurality of peripheral vehicles; 2. The driving assistance device according to claim 1, wherein, when a plurality of peripheral vehicles are present within the second range, a separate second reference position is used for each of the plurality of peripheral vehicles. This item allows risk location information to be updated more appropriately. [Item 3] The identification means When the surrounding vehicle is present within the first range, a first determination area (1102) is set for the first reference position, and when both the surrounding vehicle and the host vehicle have passed through the first determination area, the intersection specifying operation is executed; 3. The driving assistance device according to claim 1, wherein, when the surrounding vehicle is present within the second range, a second determination area (903) is set for the second reference position, and when both the surrounding vehicle and the host vehicle pass through the second determination area, the intersection identification operation is performed. This item allows risk location information to be updated more appropriately. [Item 4] Item 4. The driving assistance device according to item 3, wherein the specifying means sets the first determination 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 risk location information to be updated more appropriately. [Item 5] 5. The driving assistance device according to claim 3, wherein the specifying means sets the second determination region so as to include the second reference position. This item allows risk location information to be updated more appropriately. [Item 6] the acquisition means repeatedly acquires the nearby vehicle information from the nearby vehicle; The identification means When a new surrounding vehicle different from the surrounding vehicle is present within the first range and the first determination area has been set, the first determination area is not newly set, 6. The driving assistance device according to any one of items 3 to 5, wherein, when the surrounding vehicle is present within the second range, the second reference position is updated based on newly acquired surrounding vehicle information, and the second determination area is updated accordingly. This item allows risk location information to be updated more appropriately. [Item 7] The identification means After the first determination area is set, when the intersection identifying operation is completed or when the host vehicle moves away from the first reference position by a predetermined distance or more, the first determination area is deleted; 7. The driving assistance device according to any one of items 3 to 6, wherein after the second judgment area is set, the second judgment area is deleted when the intersection identification operation is completed or when the host vehicle moves away from the updated second reference position by a predetermined distance or more. According to this item, the capacity of the storage unit can be used appropriately. [Item 8] A driving assistance method executed by a vehicle (100), The host vehicle includes a storage means (111) for storing risk position information (112) representing a position where the host vehicle may collide with another vehicle (RV), and the driving assistance method includes: an assistance step (S409) of providing driving assistance to the host vehicle based on the risk position information; an acquisition step (S603) of acquiring, from a surrounding vehicle (RV) present around the host vehicle, surrounding vehicle information indicating a vehicle speed, a position, and a traveling trajectory of the surrounding vehicle by vehicle-to-vehicle communication; A determination step (S808, S1006) of performing an intersection determination operation to determine intersections (CPa, CPb) between the travel path of the host vehicle and the travel path of the surrounding vehicle; An updating step (S809, S1007) of updating the risk location information based on the intersection identified by the intersection identifying operation, The identifying step includes: When the surrounding vehicle is present within a first range (700) ahead of the host vehicle, the intersection specifying operation is executed using a position where the host vehicle accelerates after decelerating to a threshold value or less or a position where the host vehicle stops as a first reference position (1101); When the surrounding vehicle is present within a second range (701) to the side of the vehicle, the intersection between the predicted path (900) of the vehicle and the predicted path (901) of the surrounding vehicle is set as a second reference position (902) and the intersection identifying operation is performed. According to this item, risk location information can be updated appropriately, and as a result, driving assistance can be provided appropriately. [Item 9] A program for causing a computer mounted on a host vehicle (100) to execute each step of a driving assistance method, the host vehicle having a storage means (111) for storing risk position information (112) representing a position where the host vehicle may collide with another vehicle (RV), the driving assistance method comprising: an assistance step (S409) of providing driving assistance to the host vehicle based on the risk position information; an acquisition step (S603) of acquiring, from a surrounding vehicle (RV) present around the host vehicle, surrounding vehicle information indicating a vehicle speed, a position, and a traveling trajectory of the surrounding vehicle by vehicle-to-vehicle communication; A determination step (S808, S1006) of performing an intersection determination operation to determine intersections (CPa, CPb) between the travel path of the host vehicle and the travel path of the surrounding vehicle; An updating step (S809, S1007) of updating the risk location information based on the intersection identified by the intersection identifying operation, The identifying step includes: When the surrounding vehicle is present within a first range (700) ahead of the host vehicle, the intersection specifying operation is executed using a position where the host vehicle accelerates after decelerating to a threshold value or less or a position where the host vehicle stops as a first reference position (1101); When the surrounding vehicle is present within a second range (701) to the side of the vehicle, the program executes the intersection identifying operation using the intersection between the predicted path (900) of the vehicle and the predicted path (901) of the surrounding vehicle as a second reference position (902). According to this item, risk location information can be updated appropriately, and as a result, driving assistance can be provided appropriately.

[0084] 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]

[0085] 100: vehicle, 101: sensor group, 102: GNSS antenna, 103: vehicle-to-vehicle communication antenna, 104: alarm device, 105: braking device, 106: control device

Claims

1. A driving assistance device, a storage means for storing risk position information indicating a position where a host vehicle equipped with the driving assistance device may collide with another vehicle; an assistance means for providing driving assistance to the host vehicle based on the risk position information; an acquisition means for acquiring, from a surrounding vehicle present around the host vehicle, surrounding vehicle information indicating a vehicle speed, a position, and a traveling trajectory of the surrounding vehicle by vehicle-to-vehicle communication; a specifying means for executing an intersection specifying operation for specifying an intersection between the travel path of the host vehicle and the travel path of the surrounding vehicle; an update means for updating the risk location information based on the intersections identified by the intersection identifying operation, The identification means when the surrounding vehicle is present within a first range ahead of the host vehicle, a first determination area is set, the first determination area including a position where the host vehicle accelerates after decelerating to a threshold value or less or a position where the host vehicle stops, as a first reference position, and when both the surrounding vehicle and the host vehicle have passed through the first determination area, the intersection identification operation is executed; A driving assistance device that, when the surrounding vehicle is present within a second range to the side of the vehicle, sets a second judgment area that includes an intersection between the predicted path of the vehicle and the predicted path of the surrounding vehicle as a second reference position, and performs the intersection identification operation when both the surrounding vehicle and the vehicle pass through the second judgment area.

2. The identification means When a plurality of peripheral vehicles are present within the first range, the first reference position is used in common for the plurality of peripheral vehicles; The driving assistance device according to claim 1 , wherein, when a plurality of peripheral vehicles are present within the second range, the second reference position is used individually for each of the plurality of peripheral vehicles.

3. 2. The driving assistance device according to claim 1, wherein the specifying means sets the first determination 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.

4. The driving assistance device according to claim 1 , wherein the specifying unit sets the second determination region so as to include the second reference position.

5. the acquisition means repeatedly acquires the nearby vehicle information from the nearby vehicle; The identification means When a new nearby vehicle different from the nearby vehicle is present within the first range and the first determination area has been set, the first determination area is not newly set, 2. The driving assistance device according to claim 1, wherein, when the surrounding vehicle is present within the second range, the second reference position is updated based on newly acquired surrounding vehicle information, and the second determination area is updated accordingly.

6. The identification means After the first determination area is set, when the intersection identifying operation is completed or when the host vehicle moves away from the first reference position by a predetermined distance or more, the first determination area is deleted; 2. The driving assistance device according to claim 1, wherein the second determination area is deleted when the intersection identification operation is completed after the second determination area is set, or when the host vehicle moves away from the updated second reference position by a predetermined distance or more.

7. A driving assistance method executed by a vehicle, comprising: The host vehicle includes a storage means for storing risk position information indicating a position where the host vehicle may collide with another vehicle, and the driving assistance method includes: an assistance step of providing driving assistance to the host vehicle based on the risk position information; an acquisition step of acquiring, from surrounding vehicles present around the host vehicle, surrounding vehicle information indicating vehicle speeds, positions, and travel trajectories of the surrounding vehicles via vehicle-to-vehicle communication; a specifying step of executing an intersection specifying operation for specifying an intersection between a travel path of the host vehicle and a travel path of the surrounding vehicle; an updating step of updating the risk location information based on the intersections identified by the intersection identifying operation, The identifying step includes: When the surrounding vehicle is present within a first range ahead of the host vehicle, a first determination area is set, the first determination area including a position where the host vehicle accelerates after decelerating to a threshold value or less or a position where the host vehicle stops, as a first reference position, and when both the surrounding vehicle and the host vehicle have passed through the first determination area, the intersection identification operation is executed; a second determination area including an intersection between a predicted path of the host vehicle and a predicted path of the surrounding vehicle as a second reference position when the surrounding vehicle is present within a second range to the side of the host vehicle, and performing the intersection identification operation when both the surrounding vehicle and the host vehicle pass through the second determination area.

8. A program for causing a computer mounted on a host vehicle to execute each step of a driving assistance method, wherein the host vehicle includes a storage means for storing risk position information indicating a position where the host vehicle may collide with another vehicle, and the driving assistance method includes: an assistance step of providing driving assistance to the host vehicle based on the risk position information; an acquisition step of acquiring, from surrounding vehicles present around the host vehicle, surrounding vehicle information indicating vehicle speeds, positions, and travel trajectories of the surrounding vehicles via vehicle-to-vehicle communication; a specifying step of executing an intersection specifying operation for specifying an intersection between a travel path of the host vehicle and a travel path of the surrounding vehicle; an updating step of updating the risk location information based on the intersections identified by the intersection identifying operation, The identifying step includes: When the surrounding vehicle is present within a first range ahead of the host vehicle, a first determination area is set, the first determination area including a position where the host vehicle accelerates after decelerating to a threshold value or less or a position where the host vehicle stops, as a first reference position, and when both the surrounding vehicle and the host vehicle have passed through the first determination area, the intersection identification operation is executed; When the surrounding vehicle is present within a second range to the side of the host vehicle, a second judgment area is set that includes an intersection between the predicted path of the host vehicle and the predicted path of the surrounding vehicle as a second reference position, and when both the surrounding vehicle and the host vehicle pass through the second judgment area, the program includes:

Images