Driving assistance device and driving assistance method

Abstract

The purpose of the present invention is to provide a technique with which it is possible to correctly adjust the frequency of contact determination processing for determining contact possibility. This driving assistance device is provided with: a first acquisition unit that acquires first vehicle information including first vehicle position information including a first vehicle position and a first vehicle travel lane, and travel control information of the first vehicle; a second acquisition unit that acquires second vehicle information; and a control unit that executes contact determination processing for determining the possibility of contact between the first vehicle and the second vehicle on the basis of the first vehicle information and the second vehicle information, and frequency adjustment processing for reducing the frequency of the contact determination processing of the second vehicle as the possibility of contact of the second vehicle is lower.

Description

Driving assistance device and driving assistance method

[0001] The present disclosure relates to a driving assistance device and a driving assistance method.

[0002] A system has been proposed that includes a driving assistance device that provides driving assistance by comparing position information of a vehicle with position information of other vehicles in the vicinity of the vehicle. For example, Patent Document 1 proposes a technology that acquires position information from other vehicles in the vicinity of the vehicle, displays the positions of the other vehicles on a map display screen of a navigation system, and issues a warning as needed based on the position information. Patent Document 1 also proposes a technology that reduces the CPU processing load by lowering the probability of contact as the other vehicle is farther away from the vehicle, and lengthening the cycle of the other vehicle's position identification process as the probability of contact decreases.

[0003] For example, Patent Document 2 proposes determining the possibility of contact between one's own vehicle and another vehicle based on the structure of the road on which the other vehicle is traveling and the road on which the own vehicle is traveling, and for other vehicles for which there is no possibility of contact, lowering the possibility of contact and reducing communication traffic.

[0004] JP 2008-185454 A JP 2006-209333 A

[0005] However, in the above-described conventional technology, the vehicle position is detected not by lane but by road, each road including one or more lanes. Therefore, even if the likelihood of contact is low between the lane of the vehicle and the lane of the other vehicle, the technology may determine that the likelihood of contact is high between the road on which the vehicle is traveling and the road on which the other vehicle is traveling. As a result, the frequency of the contact determination process for determining the likelihood of contact cannot be properly adjusted, which can lead to problems such as increased CPU processing load or increased communication resources when there are many other vehicles near the vehicle.

[0006] Therefore, the present disclosure has been made in consideration of the above-mentioned problems, and aims to provide a technology that can correctly adjust the frequency of contact determination processing that determines the possibility of contact.

[0007] The driving assistance device of the present disclosure includes a first acquisition unit that acquires first vehicle information including a first vehicle position, which is the position of the first vehicle, and a first vehicle driving lane, which is the driving lane of the first vehicle, and driving control information of the first vehicle; a second acquisition unit that acquires second vehicle information including a second vehicle position, which is the position of the second vehicle; a control unit that executes a contact determination process that determines the possibility of contact between the first vehicle and the second vehicle based on the first vehicle information and the second vehicle information; a frequency adjustment process that reduces the frequency of the contact determination process of the second vehicle the lower the possibility of contact with the second vehicle; and an information provision process that provides contact-related information related to the possibility of contact to a driving assistance device of the first vehicle.

[0008] According to the present disclosure, the contact determination process is performed using first vehicle information including the first vehicle driving lane, thereby improving the accuracy of the contact determination process that determines the possibility of contact, and as a result, the frequency of the contact determination process can be correctly adjusted.

[0009] The objects, features, aspects and advantages of the present disclosure will become more apparent from the following detailed description and the accompanying drawings.

[0010] 1 is a block diagram showing a configuration of a vehicle system including a driving assistance device according to embodiment 1. FIG. 2 is a flowchart showing the operation of the driving assistance device according to embodiment 1. FIG. 3 is a diagram for explaining an example of the operation of the driving assistance device according to embodiment 1. FIG. 4 is a diagram for explaining an example of the operation of the driving assistance device according to embodiment 1. FIG. 5 is a diagram showing an example of host vehicle information. FIG. 6 is a diagram showing an example of a list of other vehicles. FIG. 7 is a diagram for explaining an example of the operation of the driving assistance device according to embodiment 1. FIG. 8 is a diagram for explaining an example of the operation of the driving assistance device according to embodiment 1. FIG. 9 is a flowchart showing the operation of the driving assistance device according to modification 1. FIG. 10 is a diagram for explaining an example of the operation of the driving assistance device according to modification 8. FIG. 11 is a block diagram showing a hardware configuration of a driving assistance device according to another modification. FIG. 12 is a block diagram showing a hardware configuration of a driving assistance device according to another modification. FIG. 13 is a block diagram showing a configuration of a server according to another modification. FIG. 14 is a block diagram showing a configuration of a communication terminal according to another modification.

[0011] <First Embodiment> Fig. 1 is a block diagram showing the configuration of a vehicle system including a driving assistance device according to the first embodiment. In the first embodiment, the vehicle system of Fig. 1 is mounted on a first vehicle. Hereinafter, the first vehicle on which the vehicle system is mounted may be referred to as a "host vehicle," and a second vehicle different from the first vehicle may be referred to as an "other vehicle."

[0012] In the following description, the first vehicle position, the first vehicle driving lane, the first vehicle position information, and the first vehicle information may be referred to as the host vehicle position, the host vehicle driving lane, the host vehicle position information, and the host vehicle information, respectively. The second vehicle position, the second vehicle driving lane, the second vehicle driving road, the second vehicle-related information, and the second vehicle information may be referred to as the other vehicle position, the other vehicle driving lane, the other vehicle driving road, the other vehicle-related information, and the other vehicle information, respectively. The vehicle system does not have to be permanently installed in the host vehicle, and may be installed in the other vehicle as well as the host vehicle.

[0013] 1 includes a driving assistance device 1, a high precision locator (HDL) 41, a V2X communication device 42 which is a communication device, and a vehicle device 43 which is a driving assistance device. First, components other than the driving assistance device 1 will be described.

[0014] <HDL 41> The HDL 41 includes a map DB (database) 41a, a satellite positioning device 41b, and a processing unit 41c. The map DB 41a stores HD (high definition) map information including road shapes for each lane. Lanes are defined by, for example, white lines on the road, and one or more lanes are included in one road. The satellite positioning device 41b performs GNSS (Global Navigation Satellite System) positioning.

[0015] The processing unit 41c detects the host vehicle position, which is the position of the host vehicle with an accuracy of the order of a few centimeters, and the host vehicle driving lane, which is the lane the host vehicle is traveling on, based on the HD map information and the positioning results of the satellite positioning device 41b. In other words, the processing unit 41c detects the host vehicle's driving lane, not the host vehicle's driving road. The processing unit 41c generates host vehicle position information including the detected host vehicle position and host vehicle driving lane. Note that the host vehicle position information may also include road shape data for each lane, such as the host vehicle's driving lane.

[0016] <V2X communication device 42> The V2X communication device 42 performs vehicle-to-vehicle communication to transmit and receive various information to and from another vehicle Q by wireless or the like.

[0017] <Vehicle Equipment 43> The vehicle equipment 43 includes an automatic driving control device 43a and a notification device 43b. The automatic driving control device 43a controls the automatic driving of the host vehicle to avoid contact with another vehicle Q based on host vehicle position information from the HDL 41 and contact-related information (described later) from the driving assistance device 1. The automatic driving control device 43a also generates driving control information for the host vehicle. The driving control information includes, for example, speed, acceleration, host vehicle direction, and driving route. The driving control information may also include, for example, lane change, driving plan, and vehicle control information. The notification device 43b issues a notification to assist the driver of the host vehicle in driving based on the contact-related information from the driving assistance device 1.

[0018] <Driving assistance device 1> Next, the driving assistance device 1 will be described. The driving assistance device 1 includes a host vehicle information acquisition unit 11 which is a first acquisition unit, an other vehicle information acquisition unit 12 which is a second acquisition unit, and a control unit 13. The driving assistance device 1 described here does not include the HDL 41, the V2X communication device 42, or the vehicle equipment 43, but the driving assistance device 1 according to the first embodiment may include at least one of the HDL 41, the V2X communication device 42, and the vehicle equipment 43. Note that in this specification, for example, "at least one of A, B, C, ..., and Z" means any one of all combinations of one or more types extracted from the group of A, B, C, ..., and Z.

[0019] The host vehicle information acquisition unit 11 acquires host vehicle information including the host vehicle position information and the host vehicle driving control information by acquiring host vehicle position information from the HDL 41 and acquiring host vehicle driving control information from the automatic driving control device 43 a. Note that the host vehicle information acquisition unit 11 may also acquire the host vehicle driving control information from an in-vehicle device other than the automatic driving control device 43 a, for example, an in-vehicle LAN (Local Area Network).

[0020] The other vehicle information acquisition unit 12 acquires other vehicle information including the other vehicle position, which is the position of the other vehicle Q, via the V2X communication device 42. In the first embodiment, all other vehicles Q are equipped with HDL, and the other vehicle information acquisition unit 12 of the host vehicle acquires the other vehicle position with an accuracy on the order of several centimeters of the other vehicle Q and the other vehicle driving lane, which is the driving lane of the other vehicle, via the V2X communication device 42. That is, in the first embodiment, the other vehicle information acquired by the other vehicle information acquisition unit 12 is multiple types of other vehicle-related information including the other vehicle position and the other vehicle driving lane.

[0021] The control unit 13 performs overall control of the driving assistance device 1, and executes a collision determination process, a frequency adjustment process, and an information provision process. An overview of these processes will be explained here, and details will be described later.

[0022] In the contact determination process, the control unit 13 determines the possibility of contact between the host vehicle and the other vehicle Q based on the host vehicle information acquired by the host vehicle information acquisition unit 11 and the other vehicle information acquired by the other vehicle information acquisition unit 12. In the first embodiment, in the contact determination process, the control unit 13 determines the possibility of contact between the host vehicle and the other vehicle Q based on the host vehicle information and the other vehicle information (i.e., multiple types of other vehicle-related information including the other vehicle position and the other vehicle driving lane).

[0023] In the frequency adjustment process, the control unit 13 reduces the frequency of the contact determination process for the other vehicle Q as the possibility of contact with the other vehicle Q decreases. In the status provision process, the control unit 13 provides contact-related information related to the possibility of contact to the vehicle device 43 of the host vehicle.

[0024] <Operation> Fig. 2 is a flowchart showing the operation of the driving assistance device 1 according to the present embodiment 1. Figs. 3 and 4 are diagrams for explaining an example of the operation of the driving assistance device 1 according to the present embodiment 1 in accordance with the flowchart of Fig. 2.

[0025] 3 and 4 show the subject vehicle P and other vehicles Q11, Q20, Q21, Q22, Q23, Q31, and Q32 as other vehicles Q, and in Fig. 4, other vehicles Q10 and Q20 are further shown as other vehicles Q. Also shown in Fig. 3 and 4 are a road R1 having one lane L11 and a road R2 having two lanes on each side, lanes L21 and L22, with lane L11 merging with lane L21. Road R2 may have lanes other than lanes L21 and L22, such as an oncoming lane.

[0026] 3 shows the positions of the host vehicle and other vehicles at time t1. At time t1, the host vehicle P's host vehicle driving lane (lane L11) and the other vehicle driving lane (lane L11) of the other vehicle Q11 ahead of the host vehicle P are the same, and the other vehicle Q11 is proceeding to a junction point where lanes L11 and L21 merge. The other vehicle driving lane of the other vehicles Q21, Q22, and Q23 is lane L21 of road R2, and the other vehicle driving lane of the other vehicles Q31 and Q32 is lane L22 of road R2.

[0027] 4 shows the positions of the host vehicle and the other vehicles at time t2, which is later than time t1. At time t2, the other vehicle Q11 has reached the junction of lanes L11 and L21, and the host vehicle P is proceeding to the junction. The other vehicle driving lane of the other vehicle Q10 traveling behind the host vehicle P is lane L11 of road R1, the other vehicle driving lane of the other vehicles Q20, Q21, Q22, and Q23 is lane L21 of road R2, and the other vehicle driving lane of the other vehicles Q31 and Q32 is lane L22 of road R2.

[0028] 2, when the host vehicle starts traveling, the control unit 13 deletes the other vehicle information of the other vehicles, and in turn, the other vehicle list updated (or generated) based on the other vehicle information. The other vehicle list will be described in detail later.

[0029] In step S2, the vehicle information acquisition unit 11 acquires vehicle position information including the vehicle position and the vehicle driving lane from the HDL 41, and acquires vehicle information by acquiring vehicle driving control information from the automatic driving control device 43a.

[0030] Fig. 5 is a diagram showing an example of the host vehicle information for time t1 in Fig. 3. The host vehicle information includes, for the host vehicle P, for example, a vehicle ID (IDp), time (t1), position (P(t1)), speed (Vp(t1)), road (R1), lane (L11), and driving control information (Pcon).

[0031] The host vehicle information may include route information indicating a route along which the host vehicle is scheduled to travel. The host vehicle information may include the host vehicle's acceleration itself, or may include a time-series host vehicle position, a time-series speed, or driving control information from which acceleration can be calculated, thereby substantially including the host vehicle's acceleration. Similarly, the host vehicle information may include the host vehicle's speed itself, or may include a time-series host vehicle position, etc. from which speed can be calculated, thereby substantially including the host vehicle's speed. Furthermore, the host vehicle information does not need to include the host vehicle's road, since the road can be determined from the driving lane and the HD map.

[0032] In step S3, the other vehicle information acquisition unit 12 acquires other vehicle information from the other vehicle via the V2X communication device 42. The other vehicle information includes, for example, a vehicle ID, time, position, speed, traveling road, and traveling lane for the other vehicle. Note that, like the subject vehicle information, the other vehicle information may also include the traveling control information and route information of the other vehicle, or may include the speed and acceleration of the other vehicle itself, or may substantially include the speed and acceleration of the other vehicle, or may not include the traveling road.

[0033] In step S4, the control unit 13 determines whether or not another vehicle is present near the host vehicle based on the other vehicle information acquired by the other vehicle information acquisition unit 12. In the first embodiment, if another vehicle is present within a radius DJ of a fixed value (e.g., 100 m) centered on the host vehicle, the control unit 13 determines that another vehicle is present near the host vehicle. In the examples of each of Figures 3 and 4, other vehicles Q11, Q21, Q22, and Q31 are present within the radius DJ centered on the host vehicle P, so the control unit 13 determines that another vehicle is present near the host vehicle.

[0034] The control unit 13 may change the value of the radius DJ based on at least one of the speed of the host vehicle, the driving conditions of the host vehicle, the road structure ahead of the host vehicle, and the lane structure ahead of the host vehicle. For example, the control unit 13 may set the radius DJ to DJ1 when there is an increase or decrease in the number of lanes, a road merging or branching, or an intersection within 200 meters ahead of the host vehicle's road. Alternatively, the control unit 13 may set the radius DJ to DJ2, which is smaller than DJ1, when there is no increase or decrease in the number of lanes, a road merging or branching, or an intersection. Furthermore, generally, the possibility of contact between vehicles on a single-lane road is limited to rear-end collisions or collisions during overtaking, and the range in which vehicles may potentially come into contact is limited. Taking this into consideration, the control unit 13 may set the radius DJ to DJ3, which is smaller than DJ2, when the lane on which the host vehicle is traveling is a single-lane road. For example, DJ1, DJ2, and DJ3 are 200 meters, 100 meters, and 50 meters, respectively.

[0035] Furthermore, the shape of the determination area used in the determination in step S4 is not limited to a circle, but may be a rectangle or an ellipse, and may be changed based on the shape or structure of the road on which the host vehicle is traveling. For example, if the host vehicle is traveling on a highway and the other vehicle is traveling on an ordinary road, and there is no interchange within a certain distance ahead of the host vehicle, the control unit 13 may exclude the area of ​​the ordinary road from the determination area.

[0036] The determination in step S4 is not limited to the above. For example, in step S3, the other vehicle information acquisition unit 12 may determine that another vehicle is present near the host vehicle if the other vehicle information acquisition unit 12 can acquire other vehicle information via a V2X communication device 42 whose maximum communication distance is equal to or less than a certain value.

[0037] If it is determined in step S4 that another vehicle is present near the subject vehicle, the process proceeds to step S5, and if it is not determined that another vehicle is present near the subject vehicle, the process proceeds to step S1.

[0038] In step S5, the control unit 13 updates (or generates) the other vehicle list based on the other vehicle information of the other vehicles determined to be present near the host vehicle in step S4. The number of other vehicles in the other vehicle list may be the same as or different from the number of other vehicles in the previous other vehicle list.

[0039] 6 is a diagram showing an example of an other vehicle list updated (or generated) based on the other vehicle information obtained at time t1 in FIG. 3. Time-series other vehicle position information may be stored as the other vehicle's position. The speed of the other vehicle may be determined from the time-series other vehicle position information, as with the other vehicle information, or the speed of the other vehicle included in the driving control information may be used. The processing result column in FIG. 6 is set by performing the processing from step S6 onwards.

[0040] In step S6, the control unit 13 determines whether or not there is an other vehicle in the other vehicle list that has reached the determination timing corresponding to the determination period of the contact determination process. The contact determination process is the process of step S7, which will be described later. The determination period is not set to the same value for all other vehicles listed in the other vehicle list, but is set individually for each other vehicle listed in the other vehicle list. In the first embodiment, the determination period includes two types of periods (T1 = 20 ms, T2 = 100 ms), but is not limited to this and may include three or more types of periods. Furthermore, when an other vehicle is first detected within a radius DJ of the host vehicle, a T2 longer than T1 may be set for the other vehicle.

[0041] If it is determined that there is another vehicle whose timing has arrived, the process proceeds to step S7, and if it is not determined that there is another vehicle whose timing has arrived, the process proceeds to step S10. Hereinafter, the other vehicle whose timing has arrived may also be referred to as the target other vehicle.

[0042] In step S7, the control unit 13 executes a contact determination process to determine the possibility of contact between the subject vehicle and the target vehicle based on the subject vehicle information and the other vehicle information of the target vehicle. In the first embodiment, the control unit 13 determines the possibility of contact in the contact determination process based on the subject vehicle position and the subject vehicle driving lane included in the subject vehicle and the other vehicle position and the other vehicle driving lane included in the other vehicle information of the target vehicle.

[0043] Hereinafter, a case will be described in which the control unit 13 determines whether or not there is a possibility of contact between the subject vehicle and a target vehicle within TC (for example, 2 seconds) in the contact determination process. Also, a case will be described in which all vehicles are traveling at a speed of 100 km / h (i.e., 27.8 m / s) and the target vehicles are vehicles Q11, Q21, Q22, and Q31 in FIG. 3 and FIG. 4 .

[0044] 3, the other vehicle driving lane (lane L11) of the other vehicle Q11 is the same as the host vehicle driving lane (lane L11) of the host vehicle P, and the distance between the other vehicle Q11 and the host vehicle P is within the travel distance of 2 seconds, that is, 55.6 m. Therefore, the control unit 13 determines that there is a high possibility of contact between the host vehicle P and the other vehicle Q11.

[0045] On the other hand, the other-vehicle driving lane (lane L22) of the other vehicle Q31 does not merge with the host vehicle driving lane (lane L11) of the host vehicle P. Therefore, the control unit 13 determines that the possibility of contact between the host vehicle P and the other vehicle Q31 is low. Furthermore, the other-vehicle driving lane (lane L21) of the other vehicles Q21 and Q22 merges with the host vehicle driving lane (lane L11) of the host vehicle P, but the distance between the other vehicles Q21 and Q22 and the merging point exceeds 55.6 m. Therefore, the control unit 13 determines that the possibility of contact between the host vehicle P and the other vehicles Q21 and Q22 is low. Furthermore, the control unit 13 determines that the possibility of contact between the host vehicle P and the target other vehicle that is more than 55.6 m away from the host vehicle P is low. As a result of the above, at time t1 in FIG. 3 , the control unit 13 determines that only the possibility of contact between the host vehicle P and the other vehicle Q11 is high.

[0046] In the case of FIG. 4 , as in the case of FIG. 3 , the control unit 13 determines that the possibility of contact between the host vehicle P and the other vehicle Q11 is high, and determines that the possibility of contact between the host vehicle P and the other vehicle Q31 is low. Meanwhile, the other vehicle driving lane (lane L21) of the other vehicles Q21 and Q22 merges with the host vehicle driving lane (lane L11) of the host vehicle P, and the distance between the other vehicles Q21 and Q22 and the merging point is within 55.6 m. Therefore, the control unit 13 determines that the possibility of contact between the host vehicle P and the other vehicles Q21 and Q22 is high. As a result of the above, at time t2 in FIG. 4 , the control unit 13 determines that the possibility of contact between the host vehicle P and the other vehicles Q11, Q21, and Q22 is high.

[0047] The determination of the possibility of contact between the host vehicle and the target vehicle is not limited to the above. For example, in the contact determination process, the control unit 13 may determine that the possibility of contact between the host vehicle and the target vehicle is high if the distance between the host vehicle and the target vehicle is equal to or less than the host vehicle length. The control unit 13 may also determine the possibility of contact between the host vehicle and the target vehicle based on a predicted time until contact.

[0048] In step S8, the control unit 13 executes a frequency adjustment process to lower the frequency of the contact determination process for the target vehicle as the possibility of contact with the target vehicle decreases. In the first embodiment, the control unit 13 sets the determination cycle for target vehicles with a high possibility of contact to a relatively short T1, and sets the determination cycle for target vehicles with a low possibility of contact to a relatively long T2. In other words, in the frequency adjustment process, the control unit 13 lowers the frequency of the contact determination process by lengthening the cycle of the contact determination process for the target vehicle as the possibility of contact with the target vehicle decreases.

[0049] In the example of Fig. 3, the determination period for the vehicle Q11 with a high contact probability is set to a relatively short T1, and the determination period for the vehicles Q21, Q22, and Q31 with a low contact probability is set to a relatively long T2. In the example of Fig. 4, the determination period for the vehicles Q11, Q21, and Q22 with a high contact probability is set to a relatively short T1, and the determination period for the vehicle Q31 with a low contact probability is set to a relatively long T2.

[0050] According to the above configuration, even if the period T1 at which the driving assistance device 1 acquires other vehicle information from other vehicles is relatively short, the judgment period of the contact judgment process can be set to T2, which is longer than T1.

[0051] In step S9, the control unit 13 executes an information provision process to provide contact-related information related to the possibility of contact to the vehicle equipment 43 of the host vehicle. The contact-related information includes, for example, the position of the other vehicle, the lane the other vehicle is traveling in, and the possibility of contact. In the first embodiment, the frequency of the information provision process corresponds to the frequency of the contact determination process, but does not have to correspond to the frequency of the contact determination process. The automatic driving control device 43a of the vehicle equipment 43 controls the host vehicle to reduce the possibility of contact based on the contact-related information from the control unit 13, and the notification device 43b of the vehicle equipment 43 notifies the host vehicle of the possibility of contact based on the contact-related information. Note that the automatic driving control device 43a may communicate with the other vehicle via the V2X communication device 42 to mutually formulate appropriate driving plans for the host vehicle and the other vehicle.

[0052] In step S10, the control unit 13 determines whether or not the traveling of the host vehicle has ended. If it is determined that the traveling of the host vehicle has ended, the operation in FIG. 2 ends, and if it is not determined that the traveling of the host vehicle has ended, the processing proceeds to step S2. Note that when proceeding from step S10 to step S2, the control unit 13 may cause the V2X communication device 42 to transmit the host vehicle position and the host vehicle traveling lane, which are part of the host vehicle information, to other vehicles.

[0053] <Operation in Other Situations> In the above explanation, the operation of the driving assistance device when the host vehicle is heading towards a merging point has been explained, but the above operation of the driving assistance device can also be applied to other situations. Figures 7 to 9 are diagrams for explaining examples of the operation of the driving assistance device.

[0054] The situation in Fig. 7 is one in which the inter-vehicle distance of the host vehicle P is controlled, and the position of the host vehicle P in Fig. 7 is the same as the position of the other vehicle Q21 in Fig. 3. In Fig. 7, the host vehicle driving lane (lane L21) of the host vehicle P is the same as the other vehicle driving lane (lane L21) of the other vehicle Q22, but is different from the other vehicle driving lane (lane L22) of the other vehicle Q31, and the distance between the host vehicle P and the other vehicles Q22 and Q31 is within 55.6 m. In this case, the control unit 13 sets the determination period for the other vehicle Q22, which has a high possibility of contact with the host vehicle P, such as a rear-end collision, to a relatively short T1, and sets the determination period for the other vehicle Q31, which has a low possibility of contact with the host vehicle P, such as a rear-end collision, to a relatively long T2.

[0055] 8 shows a road R1 having two lanes L11 and L22 and a road R2 having two lanes L21 and L22 on each side, where the lanes L12 and L21 merge. Note that the host vehicle P's host vehicle driving lane (lane L12) is different from the other vehicle Q11's other vehicle driving lane (lane L11).

[0056] In this case, the control unit 13 determines that the possibility of contact between the host vehicle P and the other vehicle Q11 is low, and sets the determination period for the other vehicle Q11 to a relatively long T2. The control unit 13 also sets the determination periods for the other vehicles Q21, Q22, and Q23 in the same manner as in the case of FIG. 4. That is, the control unit 13 determines that the possibility of contact between the host vehicle P and the other vehicles Q21 and Q22 is high, and sets the determination period for the other vehicles Q21 and Q22 to a relatively short T1. The control unit 13 then determines that the possibility of contact between the host vehicle P and the other vehicle Q31 is low, and sets the determination period for the other vehicle Q31 to a relatively long T2.

[0057] In Fig. 9, the host vehicle driving lane of the host vehicle P is lane L11 instead of lane L12 in Fig. 8. In this case, the host vehicle driving lane (lane L11) of the host vehicle P is the same as the other vehicle driving lane (lane L11) of the other vehicle Q11, but the other vehicle driving lane (lane L21) of the other vehicles Q21 and Q22 do not merge with the host vehicle driving lane (lane L11).

[0058] Therefore, the control unit 13 determines that there is a high possibility of contact between the host vehicle P and the other vehicle Q11, and sets the determination period for the other vehicle Q11 to a relatively short T1. Also, the control unit 13 determines that there is a low possibility of contact between the host vehicle P and the other vehicles Q21, Q22, and Q31, and sets the determination period for the other vehicles Q21, Q22, and Q31 to a relatively long T2. In the configuration of the first embodiment that acquires the host vehicle's host vehicle driving lane, adjustment can be made to make the determination periods for the other vehicles Q21 and Q22 different in the situations shown in Figures 8 and 9, but such adjustment cannot be made in the configuration that acquires the host vehicle's host vehicle driving road.

[0059] Summary of First Embodiment According to the driving assistance device 1 of the first embodiment, the control unit 13 executes a contact determination process that determines the possibility of contact based on the host vehicle information and the other vehicle information, and a frequency adjustment process that decreases the frequency of the contact determination process for the other vehicle as the possibility of contact with the other vehicle decreases. With this configuration, the contact determination process is executed using the host vehicle information including the host vehicle's driving lane. This can improve the accuracy of the contact determination process that determines the possibility of contact, and as a result, can correctly adjust the frequency of the contact determination process. Therefore, it is possible to appropriately suppress an increase in CPU processing load and an increase in communication resources, for example, when there are many other vehicles near the host vehicle.

[0060] <Modification 1> In the first embodiment, the control unit 13 lengthens the cycle of the contact determination process with another vehicle as the possibility of contact with the other vehicle decreases, without changing the communication for acquiring other vehicle information about the other vehicle.

[0061] In this first modification, the control unit 13 reduces the frequency of the contact determination process for the other vehicle using the latest other vehicle information by suppressing communication for acquiring other vehicle information of the other vehicle, i.e., vehicle-to-vehicle communication, as the possibility of contact with the other vehicle decreases. In other words, when the possibility of contact with the other vehicle is low, the control unit 13 performs control to reduce the frequency with which the V2X communication device 42 acquires other vehicle information of the other vehicle. Note that examples of control to reduce the frequency with which the V2X communication device 42 acquires other vehicle information of other vehicles include, but are not limited to, the following first and second methods.

[0062] <First Method> The V2X communication device 42 communicates with other vehicles at a fixed communication cycle Tq1 and identifies the other vehicle as a communication destination based on vehicle ID information included in the header of a communication packet from the other vehicle. The V2X communication device 42 then maintains the frequency of reading other vehicle information from the header onward for other vehicles with a high probability of contact, and reduces the frequency of reading other vehicle information from the header onward for other vehicles with a low probability of contact to, for example, 1 / 5. In this case, the cycle at which the V2X communication device 42 acquires other vehicle information from other vehicles with a high probability of contact is Tq1, and the cycle at which the V2X communication device 42 acquires other vehicle information from other vehicles with a low probability of contact is Tq2 (= 5 × Tq1), which is five times Tq1. This first method is suitable for 1:N communication.

[0063] <Second Method> In response to communication requests from multiple other vehicles, the V2X communication device 42 changes the communication cycle with the other vehicles in accordance with priority while identifying the other vehicles by vehicle ID or the like. For example, the V2X communication device 42 sets the communication cycle with other vehicles with a high probability of contact to Tq1, and sets the communication cycle with other vehicles with a low probability of contact to Tq2, which is longer than Tq1. This second method is suitable for one-to-one communication.

[0064] In both the first and second methods, it is desirable that the relatively long communication period (here, Tq2) be equal to or shorter than the judgment period of the contact judgment process so that the control unit 13 does not determine the possibility of contact without updating the other vehicle list.

[0065] Fig. 10 is a flowchart showing the operation of the driving assistance device 1 according to Modification 1. The operation in Fig. 10 is the same as the operation in Fig. 2 except that steps S3, S6, and S8 are replaced with steps S3a, S6a, and S8a, and therefore steps S3a, S6a, and S8a will be mainly described below.

[0066] In step S3a, the V2X communication device 42 communicates with other vehicles in accordance with the communication cycle (Tq1, Tq2), and the other vehicle information acquisition unit 12 acquires other vehicle information from the other vehicles via the V2X communication device 42. As a result, the other vehicle information acquisition unit 12 does not acquire other vehicle information from other vehicles whose communication cycle has not yet been reached, but acquires other vehicle information from other vehicles whose communication cycle has been reached.

[0067] In step S5, the control unit 13 updates the other vehicle list with the other vehicle information of the other vehicles determined to be present near the host vehicle in step S4. Note that in this modification 1, the determination cycle (T1, T2) shown in the other vehicle list in Fig. 6 is changed to a communication cycle (Tq1, Tq2).

[0068] In step S6a, the control unit 13 determines whether the determination timing corresponding to the determination period of the contact determination process has arrived. The determination period is the same (for example, T1) for all other vehicles shown in the other vehicle list. If it is determined that the determination timing has arrived, the process proceeds to step S7, and if it is not determined that the determination timing has arrived, the process proceeds to step S10. According to step S6a, the processes of steps S7 to S9 are executed for all other vehicles shown in the other vehicle list.

[0069] In step S8a, the control unit 13 sets a communication cycle between the V2X communication device 42 and the other vehicle based on the possibility of contact with the other vehicle. In the second embodiment, the control unit 13 sets a relatively short communication cycle Tq1 between the target other vehicle with a high possibility of contact and the V2X communication device 42, and sets a relatively long communication cycle Tq2 between the target other vehicle with a low possibility of contact and the V2X communication device 42. In other words, the control unit 13 adjusts the frequency of the contact determination process for the other vehicle using the latest other vehicle information.

[0070] According to the configuration of the first modification as described above, the frequency of communication in step S3a can be reduced, and therefore an increase in communication resources can be suppressed.

[0071] Note that when proceeding from step S10 to step S2, the control unit 13 may cause the V2X communication device 42 to transmit at least one of the host vehicle information, including the host vehicle position and the host vehicle driving lane, to the other vehicle. The control unit 13 may then increase the frequency of transmission of the at least one of the host vehicle information to the other vehicle as the possibility of contact with the other vehicle increases. With this configuration, it is possible to enable the other vehicle to avoid contact with the host vehicle at an appropriate transmission frequency.

[0072] In the first modification, in step S6a, the control unit 13 determines whether or not a determination timing corresponding to the determination cycle of the contact determination process has arrived, and if it determines that the determination timing has arrived, the control unit 13 performs the process of step S7. Therefore, the processes of steps S7 to S9 are performed for all other vehicles shown in the other vehicle list.

[0073] In contrast, in the present modified example 2, in step S6a, the control unit 13 determines whether there is another vehicle whose other vehicle list has been updated based on the other vehicle information, that is, whether there is another vehicle whose new other vehicle information has been acquired in step S3a. If it is determined that there is another vehicle whose other vehicle list has been updated, the process proceeds to step S7. If it is not determined that there is another vehicle whose other vehicle list has been updated, the process proceeds to step S10. With this configuration, the processes of steps S7 to S9 are not executed for another vehicle whose other vehicle list has not been updated, which not only reduces the increase in communication resources but also reduces the increase in CPU processing.

[0074] <Modification 3> In Modification 1, the control unit 13 suppressed communication to acquire other vehicle information of another vehicle as the possibility of contact with the other vehicle became lower. In contrast, in Modification 3, the V2X communication device 42 has a memory for storing information, and the control unit 13 suppresses the other vehicle information acquisition unit 12 from acquiring other vehicle information from the V2X communication device 42 that receives the other vehicle information as the possibility of contact with the other vehicle becomes lower. That is, the control unit 13 sets the cycle for loading other vehicle information of other vehicles with a high possibility of contact from the V2X communication device 42 to the other vehicle information acquisition unit 12 to, for example, Tq1, as in Modification 1. On the other hand, the control unit 13 sets the cycle for loading other vehicle information of other vehicles with a low possibility of contact from the V2X communication device 42 to the other vehicle information acquisition unit 12 to, for example, Tq2 (= 5 × Tq1), as in Modification 1.

[0075] The block diagram of the driving assistance device 1 according to the present modified example 3 is the same as the block diagram of Figure 1, except that an arrow indicating control from the control unit 13 to the other vehicle information acquisition unit 12 has been added to the block diagram of Figure 1.

[0076] According to the configuration of the present modification 3 as described above, it is possible to reduce the memory load time and therefore increase the processing speed. Note that in the present modification 3 as well, as in the present modification 2, the processing of steps S7 to S9 does not have to be performed for other vehicles whose other vehicle list has not been updated, in which case an increase in CPU processing can be suppressed.

[0077] In the first embodiment, the possibility of contact is represented by two values, "high" or "low," and the frequency of the contact determination process is changed by two values. However, the possibility of contact may be represented by multiple values ​​corresponding to the degree of urgency, and the frequency of the contact determination process may also be changed by multiple values.

[0078] For example, the control unit 13 may increase the possibility of contact with another vehicle (multiple values) as the traveling speed of the host vehicle or the other vehicle increases. Furthermore, the control unit 13 may increase the possibility of contact with another vehicle (multiple values) as the distance between the host vehicle and the other vehicle decreases. Furthermore, when the host vehicle is traveling on a road including multiple lanes, the control unit 13 may decrease the possibility of contact with another vehicle (multiple values) as the other vehicle moves farther away from the lane the host vehicle is traveling in. Furthermore, the control unit 13 may decrease the possibility of contact with another vehicle (multiple values) as the accuracy of the autonomous driving device of the other vehicle increases or the autonomous driving level of the other vehicle increases.

[0079] Furthermore, the control unit 13 may set the importance of the contact situation with another vehicle based on the predicted results of the degree of damage when an accident such as parallel running contact, lane change contact, rear-end collision, merging collision, or head-on collision occurs, and the higher the importance of the other vehicle, the higher the possibility (multiple values) of contact with the other vehicle. For example, the control unit 13 may set the importance in the order of parallel running contact, lane change contact, rear-end collision, merging collision, and head-on collision.

[0080] According to the configuration of the fourth modification as described above, the accuracy of the contact determination process and the frequency adjustment process can be improved.

[0081] <Variation 5> In the first embodiment, all other vehicles are equipped with HDLs, and the other vehicle information acquired by the other vehicle information acquisition unit 12 from other vehicles equipped with HDLs is multiple types of other vehicle-related information, including the other vehicle's position and the lane the other vehicle is traveling on. In this variation 5, all other vehicles are equipped with SDLs (standard precision locators) instead of HDLs. In this case, the other vehicle information acquired by the other vehicle information acquisition unit 12 from other vehicles equipped with SDLs is multiple types of other vehicle-related information, including the other vehicle's position with an accuracy on the order of several meters and the road the other vehicle is traveling on instead of the lane the other vehicle is traveling on. Furthermore, in the contact determination process, the control unit 13 determines the possibility of contact based on the host vehicle's position, the host vehicle's lane, the other vehicle's position, and the road the other vehicle is traveling on.

[0082] The operation of the driving assistance device according to this variant 5 is almost the same as the operation of the driving assistance device according to embodiment 1 of Figure 2, but the other vehicle information acquired in step S3 does not include the lane in which other vehicles are traveling, and the other vehicle list of Figure 6 updated in step S5 does not include the lane in which other vehicles are traveling.

[0083] An example of the operation of the driving assistance device 1 according to Modification 5 will be described below with reference to Figures 3 and 4. In Figures 3 and 4, the control unit 13 can determine that the other vehicle Q11 is traveling in the same lane L11 as the host vehicle's driving lane while the other vehicle Q11 ahead of the host vehicle P is traveling on road R1. Therefore, the contact determination process and frequency adjustment process for the other vehicle Q11 in Modification 5 are the same as those in Embodiment 1.

[0084] On the other hand, the control unit 13 can determine that the other vehicles Q21, Q22, and Q31 are traveling on road R2, but cannot determine which of lanes L21 and L22 they are traveling in. Therefore, the control unit 13 determines that the other vehicles Q21, Q22, and Q31 are traveling in lane L21, which merges with the host vehicle's lane (lane L11), and executes the contact determination process and the frequency adjustment process.

[0085] As a result, at time t1 in Figure 3, the distance between the other vehicles Q21, Q22, and Q31 and the merging point exceeds 55.6 m, so the determination periods of the other vehicles Q11, Q21, Q22, and Q31 are set to T1, T2, T2, and T2, respectively. On the other hand, at time t2 in Figure 4, the distance between the other vehicles Q21, Q22, and Q31 and the merging point is within 55.6 m, so the determination periods of the other vehicles Q11, Q21, Q22, and Q31 are set to T1, T1, T1, and T1, respectively. In other words, the determination period of the other vehicle Q31 at time t2 in Figure 4 is different from the determination period in the first embodiment.

[0086] According to the configuration of the fifth modification as described above, even when the other vehicle is equipped with an SDL and the other vehicle information acquisition unit 12 cannot acquire the other vehicle's driving lane, it is possible to suppress an increase in CPU processing load and an increase in communication resources to some extent. The control unit 13 may provide the automatic driving control device 43a with information indicating that the accuracy of the other vehicle's position is equivalent to the SDL, included in the contact-related information. In this case, the automatic driving control device 43a can control the automatic driving of the host vehicle after recognizing that the accuracy of the other vehicle's position is equivalent to the SDL.

[0087] <Variation 6> In Variation 5, it has been described that all other vehicles are equipped with SDLs. In Variation 6, the other vehicles include SDL-equipped vehicles and HDL-equipped vehicles, and the operation of Variation 6 is a combination of the operation of Embodiment 1 and the operation of Variation 5. In such a case, the control unit 13 may include information indicating whether the positions of each other vehicle have accuracy equivalent to an HDL or an SDL in the contact-related information and provide the information to the automatic driving control device 43a.

[0088] In general, SDL-equipped vehicles have a lower reliability of autonomous driving than HDL-equipped vehicles, and therefore, in the contact determination process, the control unit 13 may lower the threshold value for determining the possibility of contact so as to make it easier to determine that there is a high possibility of contact with an SDL-equipped vehicle. In addition, since the accuracy of other vehicle information including the road on which the other vehicle is traveling is generally lower than the accuracy of other vehicle information including the lane on which the other vehicle is traveling, the control unit 13 may determine that the lower the accuracy of the multiple types of other-vehicle-related information that is the other-vehicle information, the higher the possibility of contact.

[0089] Furthermore, if the SDL-equipped vehicle has a function of determining the lane in which other vehicles are traveling by image processing or the like, the other vehicle information acquisition unit 12 may acquire the lane in which other vehicles are traveling from the other vehicles. In this case, the control unit 13 may execute the same contact determination process for the SDL-equipped vehicle that has the function of determining the lane in which other vehicles are traveling as for the HDL-equipped vehicle.

[0090] According to the configuration of the sixth modification as described above, the accuracy of the contact determination process and the frequency adjustment process can be improved.

[0091] <Seventh Modification> In the first embodiment, the multiple types of other vehicle-related information, which is other vehicle information, include the other vehicle position and the other vehicle driving lane. However, in the seventh modification, the other vehicle information further includes driving control information of the other vehicle.

[0092] The cruise control information may include, for example, the steering wheel angle and turn signal information of the other vehicle, information on a plan for the cruise control device of the other vehicle to change the driving lane within 10 meters, etc. In such a case, the control unit 13 may predict whether the other vehicle will change the driving lane based on the other vehicle information including the cruise control information of the other vehicle.

[0093] In the first embodiment, in the situation shown in Figure 4, the control unit 13 determined that there is a high possibility of contact between the host vehicle P and the other vehicles Q21 and Q22, whose lane of travel is the same as the host vehicle's lane and whose distance to the merging point is within 55.6 meters. In the seventh modification, in addition to this determination, the control unit 13 determines whether at least one of the other vehicles Q21 and Q22 will move into lane L22 based on the driving control information from the other vehicles Q21 and Q22. Then, the control unit 13 determines that there is a low possibility of contact with the other vehicle Q21 or Q22 that is determined to move into lane L22.

[0094] As in the fourth modification, the contact possibility may be multiple values, such as high, medium, and low. For example, when the control unit 13 determines that the other vehicle Q22 will continue traveling in the lane L21, the control unit 13 determines that the contact possibility with the other vehicle Q22 is high. For example, when the control unit 13 determines that the other vehicle Q22 will move to the lane L22, the control unit 13 determines that the contact possibility with the other vehicle Q22 is medium, taking into account the possibility that the movement will be canceled. For example, when the control unit 13 determines that the other vehicle Q31 will continue traveling in the lane L22, the control unit 13 determines that the contact possibility with the other vehicle Q31 is low.

[0095] Furthermore, when the driving control information includes a speed change of the other vehicle, the control unit 13 may calculate the time until contact between the host vehicle and the other vehicle based on the driving control information of the other vehicle, and determine the possibility of contact with the other vehicle based on the calculated time. Furthermore, when the driving control information includes the autonomous driving level of the other vehicle, the control unit 13 may determine based on the driving control information that the higher the autonomous driving level of the other vehicle, the lower the possibility of contact with the other vehicle.

[0096] According to the configuration of the seventh modification as described above, the accuracy of the contact determination process and the frequency adjustment process can be improved.

[0097] <Modification 8> In Modification 8, the multiple types of other-vehicle-related information that is other-vehicle information further includes route information that indicates a route along which the other vehicle is scheduled to travel.

[0098] 11 is a diagram illustrating an example of the operation of the driving assistance device 1 according to Modification 8. In Fig. 11, lane L21 of road R2 branches off into lane L31 of road R3 just before merging with lane L11 of road R1.

[0099] 11 , when the route information of the other vehicle Q22 indicates lane L31, the control unit 13 determines that the possibility of contact between the host vehicle P and the other vehicle Q22 is low. When the other vehicle Q22 does not follow the route information, that is, when the other vehicle Q22 travels on lane L22 instead of lane L31, the control unit 13 determines that the possibility of contact between the host vehicle P and the other vehicle Q22 is high. Note that when the multiple types of other-vehicle-related information that is the other-vehicle information include the reliability of the route information, the control unit 13 may determine the possibility of contact based on the reliability of the route information.

[0100] According to the configuration of the eighth modified example as described above, the accuracy of the contact determination process and the frequency adjustment process can be improved.

[0101] <Modification 9> In this modification 9, the other vehicles include a first other vehicle, which is a 2-1 vehicle, and a second other vehicle, which is a 2-2 vehicle. Furthermore, the multiple types of other-vehicle-related information, which is the other-vehicle information of the first other vehicle, further includes proximity detection information, such as relative position information of the second other vehicle with respect to the first other vehicle. Furthermore, in the contact determination process, the control unit 13 determines the possibility of contact between the subject vehicle and the second other vehicle based on the subject vehicle information and the multiple types of other-vehicle-related information, which is the other-vehicle information of the first other vehicle. Then, in the frequency adjustment process, the control unit 13 decreases the frequency of the contact determination process for the second other vehicle, which uses the multiple types of other-vehicle-related information, which is the other-vehicle information of the first other vehicle, the lower the possibility of contact with the second other vehicle.

[0102] Hereinafter, first to third examples of the operation of the driving assistance device 1 according to the ninth modification will be described with reference to FIGS. 3 and 4. FIG.

[0103] In the first example, other vehicles Q21 and Q22 are HDL-equipped vehicles, and the other vehicle information of other vehicles Q21 and Q22 includes not only the other vehicle position and the other vehicle driving lane with an accuracy of sub-m order, but also proximity detection information. Also, other vehicle Q31 is an SDL-equipped vehicle, and the other vehicle information of other vehicle Q31 includes the other vehicle position and the other vehicle driving road with an accuracy of several m order.

[0104] In this case, the control unit 13 cannot determine whether the other vehicle Q31 is traveling in lane L21 or L22 from the other vehicle information of the other vehicle Q31. However, if the other vehicle information of the other vehicle Q22 includes relative position information of the other vehicle Q31 (second other vehicle) with respect to the other vehicle Q22 (first other vehicle), the control unit 13 can determine that the other vehicle Q31 is traveling in lane L22 from the relative position information. Furthermore, the control unit 13 can correct the position of the other vehicle Q31 based on the relative position information. Therefore, the control unit 13 determines that the possibility of contact with the other vehicle Q31 is low, and can reduce the frequency of the contact determination process for the other vehicle Q31.

[0105] In the second example, the other vehicle Q21 is an HDL-equipped vehicle, and the other vehicle information of the other vehicle Q21 includes not only the other vehicle position and the other vehicle driving lane with an accuracy of sub-m order, but also proximity detection information. Also, the other vehicle Q22 is an SDL-equipped vehicle, and the other vehicle information of the other vehicle Q22 includes the other vehicle position and the other vehicle driving road with an accuracy of several m order.

[0106] In this case, the control unit 13 cannot determine whether the other vehicle Q22 is traveling in lane L21 or L22 from the other vehicle information of the other vehicle Q22. However, if the other vehicle information of the other vehicle Q21 includes relative position information of the other vehicle Q22 (second other vehicle) with respect to the other vehicle Q21 (first other vehicle), the control unit 13 can determine that the other vehicle Q22 is traveling in lane L21 from the relative position information. The control unit 13 can also correct the position of the other vehicle Q22 based on the relative position information. Therefore, the control unit 13 determines that there is a high possibility of contact with the other vehicle Q22 and can increase the frequency of the contact determination process for the other vehicle Q22.

[0107] In the third example, another vehicle Q22 within a radius DJ from the host vehicle P is an SDL-equipped vehicle, and another vehicle Q21 outside the radius DJ from the host vehicle P is an HDL-equipped vehicle. In this case, the control unit 13 may increase the frequency of acquiring other vehicle information from the other vehicle Q21, which is an HDL-equipped vehicle, in order to increase the frequency of the contact determination process between the host vehicle P and the other vehicle Q22, which is an SDL-equipped vehicle.

[0108] According to the configuration of the present variant example 9 as described above, even if the other vehicle information of the second other vehicle does not include the other vehicle position and the other vehicle driving lane with accuracy of sub-m order, the accuracy of the contact determination processing and frequency adjustment processing for the second other vehicle can be improved.

[0109] In Modification 10, the multiple types of other-vehicle-related information that constitute the other-vehicle information further include travel regulation information such as lane change regulations for the lane in which the other vehicle is traveling, traffic divisions by direction of travel, and speed regulations. With this configuration, the control unit 13 can execute highly accurate contact determination processing by comparing the information with regulation information related to the direction of travel of the lane in which the host vehicle is traveling.

[0110] The multiple types of other-vehicle-related information, which is the other-vehicle information, may further include the positions of zebra zones and road signs detected by the other vehicle. The control unit 13 may estimate the other vehicle's driving lane based on the positions of the zebra zones and road signs detected by the other vehicle, the absolute positions at which the zebra zones are marked in the map DB of the host vehicle, and the absolute positions at which the road signs are installed. With this configuration, even if the other vehicle is an SDL-equipped vehicle, the control unit 13 can perform highly accurate contact determination processing using the estimated other vehicle's driving lane.

[0111] <Modification 11> In Modification 11, the control unit 13 changes the type of other-vehicle-related information, which is other-vehicle information to be used in the next contact determination process, based on the history of the contact possibility determined in the contact determination process.

[0112] As a first example, the control unit 13 may increase the types of other-vehicle-related information, which is other-vehicle information, to be used in the next contact determination process, as the likelihood of contact determined in the contact determination process increases. For example, if the control unit 13 determines that the likelihood of contact is low in the contact determination process, the control unit 13 may use the other-vehicle position in the next contact determination process, and if the control unit 13 determines that the likelihood of contact is high in the contact determination process, the control unit 13 may use the other-vehicle position and the other-vehicle driving lane in the next contact determination process.

[0113] As a second example, the other vehicle information acquisition unit 12 acquires multiple types of other vehicle-related information, including route information and cruise control information, as other vehicle information, and the control unit 13 changes the type of other vehicle-related information to be used in the next contact determination process based on the history of the contact possibility. For example, if the history indicates a high possibility of contact in the contact determination process, typically if the control unit 13 determines that there is a high possibility of an upcoming contact, the control unit 13 may use all of the other vehicle position, the other vehicle's driving lane, route information, and cruise control information in the next contact determination process. On the other hand, if the control unit 13 determines that there is a low possibility of an upcoming contact, the control unit 13 may use only the other vehicle position in the next contact determination process.

[0114] According to the configuration of the present modified example 11 as described above, it is possible to improve the accuracy of the contact determination process and the frequency adjustment process.

[0115] As in the fourth modification, the contact possibility may be multiple values, such as "high," "medium," and "low." For example, the control unit 13 may use only the other vehicle position in the next contact determination process when the upcoming contact possibility is "low," use the other vehicle position and the other vehicle's driving lane in the next contact determination process when the upcoming contact possibility is "medium," and use the other vehicle position, the other vehicle's driving lane, route information, and driving control information in the next contact determination process when the upcoming contact possibility is "high." The control unit 13 may also instruct the V2X communication device 42 not to acquire information not used in the contact determination process, thereby reducing communication resources. The control unit 13 may also instruct the other vehicle information acquisition unit 12 not to read information not used in the contact determination process from the V2X communication device 42, thereby increasing the processing speed.

[0116] <Modification 12> In Modification 12, the control unit 13 determines that the possibility of contact is higher when there are fewer types of other-vehicle-related information or when the accuracy of the multiple types of other-vehicle-related information is lower for the multiple types of other-vehicle-related information that are other-vehicle information. The multiple types of other-vehicle-related information include, for example, the position of the other vehicle, the road on which the other vehicle is traveling, the lane on which the other vehicle is traveling, route information, and driving control information. The accuracy of the other-vehicle-related information is, for example, positioning accuracy. With this configuration, the accuracy of the contact determination process and the frequency adjustment process can be improved.

[0117] If the SDL-equipped vehicle has a function for determining the lane in which other vehicles are traveling by image processing or the like, the other vehicle information acquisition unit 12 may acquire the lane in which other vehicles are traveling from the other vehicle. Then, the control unit 13 may perform the same contact determination process for the SDL-equipped vehicle that has the function for determining the lane in which other vehicles are traveling as for the HDL-equipped vehicle. Alternatively, the control unit 13 may determine that the accuracy of the other vehicle-related information from the SDL-equipped vehicle that has the function for determining the lane in which other vehicles are traveling is higher than the accuracy of the other vehicle-related information from the SDL-equipped vehicle that does not have the function for determining the lane in which other vehicles are traveling, but lower than the accuracy of the other vehicle-related information from the HDL-equipped vehicle.

[0118] <Modification 13> In the first embodiment, it has been described that the control unit 13 may cause the V2X communication device 42 to transmit the host vehicle position and the host vehicle driving lane, which are part of the host vehicle information, to another vehicle. In contrast to this, in the present modification 13, the control unit 13 changes the type of information to be transmitted from the V2X communication device 42 to another vehicle based on the possibility of contact.

[0119] For example, when the possibility of contact with another vehicle is a first possibility of contact, the control unit 13 may cause the V2X communication device 42 to transmit the position of the host vehicle to the other vehicle, and when the possibility of contact with the other vehicle is a second possibility of contact that is higher than the first possibility of contact, the control unit 13 may cause the V2X communication device 42 to transmit the position of the host vehicle and the lane the host vehicle is traveling in to the other vehicle. Alternatively, when the possibility of contact with the other vehicle is the second possibility of contact, the control unit 13 may cause the V2X communication device 42 to transmit not only the position of the host vehicle and the lane the host vehicle is traveling in, but also driving control information of the host vehicle to the other vehicle.

[0120] According to the configuration of the present modification 13 as described above, an increase in communication resources can be suppressed.

[0121] <Other Modifications> The subject vehicle information acquisition unit 11, the other vehicle information acquisition unit 12, and the control unit 13 shown in FIG. 1 described above will hereinafter be referred to as the "subject vehicle information acquisition unit 11, etc." The subject vehicle information acquisition unit 11, etc. are realized by a processing circuit 81 shown in FIG. 12. That is, the processing circuit 81 includes the subject vehicle information acquisition unit 11 that acquires subject vehicle information, the other vehicle information acquisition unit 12 that acquires other vehicle information, and the control unit 13 that executes contact determination processing, frequency adjustment processing, and information provision processing. Dedicated hardware may be applied to the processing circuit 81, or a processor that executes a program stored in a memory may be applied. Examples of the processor include a central processing unit, a processing unit, an arithmetic unit, a microprocessor, a microcomputer, and a DSP (Digital Signal Processor).

[0122] When the processing circuitry 81 is dedicated hardware, the processing circuitry 81 corresponds to, for example, a single circuit, a composite circuit, a programmed processor, a parallel programmed processor, an ASIC (Application Specific Integrated Circuit), an FPGA (Field Programmable Gate Array), or a combination thereof. The functions of each unit such as the host vehicle information acquisition unit 11 may be realized by a circuit in which the processing circuits are distributed, or the functions of each unit may be realized together by a single processing circuit.

[0123] When the processing circuit 81 is a processor, the functions of the host vehicle information acquisition unit 11 and the like are realized in combination with software and the like. The software and the like may include, for example, software, firmware, or software and firmware. The software and the like are written as a program and stored in a memory. As shown in FIG. 13 , the processor 82 applied to the processing circuit 81 realizes the functions of each unit by reading and executing a program stored in a memory 83. That is, the driving assistance device 1 includes a memory 83 for storing a program that, when executed by the processing circuit 81, results in the execution of a step of acquiring host vehicle information, a step of acquiring other vehicle information, and a step of executing a contact determination process, a frequency adjustment process, and an information provision process. In other words, the program can be said to cause a computer to execute the procedures and methods of the host vehicle information acquisition unit 11 and the like. Here, the memory 83 may be, for example, a non-volatile or volatile semiconductor memory such as a RAM (Random Access Memory), a ROM (Read Only Memory), a flash memory, an EPROM (Erasable Programmable Read Only Memory), or an EEPROM (Electrically Erasable Programmable Read Only Memory), a HDD (Hard Disk Drive), a magnetic disk, a flexible disk, an optical disk, a compact disk, a mini disk, a DVD (Digital Versatile Disc), a drive device for any of these, or any storage medium to be used in the future.

[0124] The above describes a configuration in which each function of the host vehicle information acquisition unit 11, etc. is realized either by hardware or software, etc. However, this is not limited to this, and a configuration in which part of the host vehicle information acquisition unit 11, etc. is realized by dedicated hardware and another part is realized by software, etc. For example, the function of the host vehicle information acquisition unit 11 can be realized by a processing circuit 81 as dedicated hardware, and the other functions can be realized by the processing circuit 81 as a processor 82 reading and executing programs stored in a memory 83.

[0125] As described above, the processing circuitry 81 can realize the above-described functions by hardware, software, or a combination of these.

[0126] The driving assistance device 1 described above can also be applied to a driving assistance system constructed as a system by appropriately combining a vehicle device, a communication terminal, the functions of an application installed on at least one of the vehicle device and the communication terminal, and a server. Examples of the vehicle device include a portable navigation device (PND) and a navigation device. Examples of the communication terminal include a mobile phone, a smartphone, and a tablet. The functions or components of the driving assistance device described above may be distributed among the devices that constitute the system, or may be centrally located in one of the devices.

[0127] Fig. 14 is a block diagram showing the configuration of a server 91 according to this modification. The server 91 in Fig. 14 includes a communication unit 91a and a control unit 91b, and is capable of wireless communication with a vehicle device 93 of the host vehicle P.

[0128] The communication unit 91 a , which is the first acquisition unit and the second acquisition unit, receives the subject vehicle information and other vehicle information acquired by the vehicle device 93 by wirelessly communicating with the vehicle device 93 .

[0129] The control unit 91b has the same functions as the control unit 13 in FIG. 1 by a processor (not shown) of the server 91 executing a program stored in a memory (not shown) of the server 91. That is, the control unit 91b executes a contact determination process, a frequency adjustment process, and an information provision process to generate contact-related information. The communication unit 91a then transmits the contact-related information to the vehicle device 93. The server 91 configured in this manner can achieve the same effects as the driving assistance device 1 described in the first embodiment.

[0130] Fig. 15 is a block diagram showing the configuration of a communication terminal 96 according to this modification. The communication terminal 96 in Fig. 15 includes a communication unit 96a similar to the communication unit 91a and a control unit 96b similar to the control unit 91b, and is capable of wireless communication with a vehicle device 98 of the vehicle P. Note that the communication terminal 96 may be, for example, a mobile terminal such as a mobile phone, smartphone, or tablet carried by the driver of the vehicle P. The communication terminal 96 configured in this manner can achieve the same effects as the driving assistance device 1 described in the first embodiment.

[0131] The contents of the embodiments can be modified or omitted as appropriate.

[0132] The above description is illustrative in all respects and is not restrictive. It is understood that countless variations not illustrated can be envisioned.

[0133] 1 driving assistance device, 11 host vehicle information acquisition unit, 12 other vehicle information acquisition unit, 13 control unit, 41 HDL, 42 V2X communication device, 43 vehicle equipment, P host vehicle, Q other vehicle.

Claims

1. A first acquisition unit acquires first vehicle information including first vehicle position information, which includes the position of the first vehicle and the lane in which the first vehicle travels, and first vehicle driving control information for the first vehicle. A second acquisition unit acquires second vehicle information, including the second vehicle position, which is the position of the second vehicle. A control unit that performs a contact determination process to determine the possibility of contact between the first vehicle and the second vehicle based on the first vehicle information and the second vehicle information; a frequency adjustment process to lower the frequency of the contact determination process for the second vehicle as the possibility of contact for the second vehicle decreases; and an information provision process to provide contact-related information related to the possibility of contact to the driver assistance equipment of the first vehicle. Equipped with, The aforementioned vehicle information is, High-precision, multiple types of second vehicle-related information, including the second vehicle's position and the second vehicle's driving lane, or This is a set of multiple types of standard-precision information related to the second vehicle, including the position of the second vehicle and the second vehicle travel road, which is the road on which the second vehicle travels. If the second vehicle information is the high-precision, multiple types of second vehicle-related information, the control unit determines the possibility of contact based on the second vehicle lane and the first vehicle lane in the contact determination process. If the second vehicle information is a plurality of types of second vehicle-related information of standard accuracy, the control unit determines the possibility of contact based on the second vehicle travel road and the first vehicle travel lane in the contact determination process, a driving assistance device.

2. A driving support device according to Claim 1, A driving assistance device in which, when the second vehicle information is a plurality of types of second vehicle-related information of standard accuracy, and the first vehicle lane merges with a main road having multiple lanes, the control unit performs the contact determination process assuming that the second vehicle traveling on the main road is traveling in a lane of the multiple lanes that merges with the first vehicle lane.

3. A driving support device according to Claim 1, The aforementioned multiple types of second vehicle-related information further include route information of the second vehicle, or driving control information of the second vehicle. The control unit, A driver assistance device that determines in the contact determination process that the fewer the types of the second vehicle-related information, or the lower the accuracy of the multiple types of second vehicle-related information, the higher the probability of contact.

4. A driving support device according to claim 1, The control unit, A driving assistance device that, in the frequency adjustment process, lengthens the cycle of the contact determination process for the second vehicle when the likelihood of contact with the second vehicle is low, or when the second vehicle information is high-precision multiple types of second vehicle-related information.

5. A driving support device according to claim 1, The control unit, A driver assistance device that suppresses communication for receiving second vehicle information from the second vehicle when the likelihood of contact with the second vehicle is low, or when the second vehicle information is high-precision, multi-type second vehicle-related information.

6. A driving support device according to claim 1, The control unit, A driver assistance device that suppresses the acquisition of the second vehicle information by the second acquisition unit from a communication device that receives the second vehicle information from the second vehicle, when the likelihood of contact with the second vehicle is low, or when the second vehicle information is high-precision, multi-type second vehicle-related information.

7. A driving support device according to claim 1, The aforementioned second vehicle includes the second-first vehicle and the second-second vehicle, The plurality of types of second vehicle-related information of the second-first vehicle further includes relative position information of the second-second vehicle with respect to the second-first vehicle, The control unit, A driving assistance device that, in the contact determination process, determines the possibility of contact between the first vehicle and the second vehicle based on the first vehicle information, the multiple types of second vehicle-related information of the second vehicle second-1, and whether the second vehicle information of the second vehicle second-1 and the second vehicle second-2 is the high-precision multiple types of second vehicle-related information or the standard-precision multiple types of second vehicle-related information, and in the frequency adjustment process, the frequency of the contact determination process for the second vehicle using the multiple types of second vehicle-related information of the second vehicle second-1 is reduced as the possibility of contact with the second vehicle second-2 decreases.

8. A driving support device according to claim 1, The control unit, A driver assistance device that determines in the contact determination process that the likelihood of contact is high when the number of types of the second vehicle-related information is small, when the accuracy of the multiple types of second vehicle-related information is low, or when the second vehicle information is the standard accuracy of multiple types of second vehicle-related information.

9. A driving support device according to claim 1, The control unit, A driver assistance device that changes the type of the second vehicle-related information, which is the second vehicle information to be used in the next contact determination process, based on the history of the possibility of contact determined in the contact determination process and whether the second vehicle information is the high-precision, multiple-type second vehicle-related information or the standard-precision, multiple-type second vehicle-related information.

10. A driving support device according to claim 1, The system further includes a high-precision locator that has high-precision map information including road shape on a lane-by-lane basis, and detects the first vehicle position and the first vehicle's lane based on the high-precision map information, The first acquisition unit is a driving support device that acquires first vehicle position information, including the first vehicle position and the first vehicle lane, from the high-precision locator.

11. The first acquisition unit acquires first vehicle information including first vehicle position information, which includes a first vehicle position, which is the position of the first vehicle, and a first vehicle driving lane, which is the driving lane of the first vehicle, and driving control information of the first vehicle. The second acquisition unit acquires second vehicle information, including the second vehicle position, which is the location of the second vehicle. The control unit performs a contact determination process that determines the possibility of contact between the first vehicle and the second vehicle based on the first vehicle information and the second vehicle information, a frequency adjustment process that lowers the frequency of the contact determination process for the second vehicle as the possibility of contact for the second vehicle decreases, and an information provision process that provides contact-related information related to the possibility of contact to the driver assistance equipment of the first vehicle. The aforementioned vehicle information is, High-precision, multiple types of second vehicle-related information, including the second vehicle's position and the second vehicle's driving lane, or This is a set of multiple types of standard-precision information related to the second vehicle, including the position of the second vehicle and the second vehicle travel road, which is the road on which the second vehicle travels. If the second vehicle information is the high-precision, multiple types of second vehicle-related information, the control unit determines the possibility of contact based on the second vehicle lane and the first vehicle lane in the contact determination process. If the second vehicle information is a plurality of types of second vehicle-related information of standard accuracy, the control unit determines the possibility of contact based on the second vehicle travel road and the first vehicle travel lane in the contact determination process, in a driving assistance method.