Operation support apparatus, operation support method, and operation support program

Abstract

To provide an operation support apparatus, an operation support method, and an operation support program, which are capable of determining applicability to enter a roundabout quickly.SOLUTION: An operation support apparatus includes an operation support configured to determine applicability of a vehicle itself entering a roundabout on the basis of obtained information of the roundabout and information on a target acquired by a target information acquisition device, and to perform an operation support in entering the roundabout by notifying a driver of the result of the determination. The apparatus performs: estimating a first travel time T0 until the vehicle itself arrives at an entrance point to the roundabout; estimating a second travel time T1 until a heading other vehicle traveling within the roundabout reaches the entrance point; and determining applicability of the vehicle itself entering the roundabout on the basis of relationship between the first and second travel time.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to driving assistance for vehicles such as automobiles, and more particularly to a driving assistance device, a driving assistance method, and a driving assistance program that assist driving when entering a roundabout. [Background technology]

[0002] A known driving assistance device that assists a vehicle in driving when entering a roundabout is one that assesses the status of other vehicles traveling within the roundabout and, based on the assessment results, determines whether the vehicle can enter the roundabout.

[0003] For example, Patent Document 1 below describes that when a vehicle reaches a roundabout, it determines whether other vehicles traveling within the roundabout are aggressive, and if it determines that the other vehicles are aggressive, it slows down the vehicle so that the other vehicles pass in front of the vehicle. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2022-173452 Summary of the Invention

[0005] [Problem to be solved by the invention] According to a conventional driving assistance device such as the driving assistance device described in Patent Document 1, when the vehicle enters the roundabout, the risk of collision with other vehicles traveling within the roundabout can be reduced.

[0006] However, the determination of whether other vehicles traveling within the roundabout are aggressive is made when the vehicle reaches the roundabout, so it is not possible to determine early on whether the vehicle can enter the roundabout as it approaches the roundabout.

[0007] The present invention provides a driving assistance device, a driving assistance method, and a driving assistance program that can determine whether or not to enter a roundabout earlier than conventional methods by determining the relationship between the time required for other vehicles traveling within the roundabout and the vehicle itself to reach the entry position into the roundabout. [Means for solving the problems and effects of the invention]

[0008] According to the present invention, there is provided a driving assistance device (100) including a target information acquisition device (18) that acquires information on targets ahead of the vehicle (102), and a control unit (driving assistance ECU 10) that acquires information on a roundabout (110) ahead of the vehicle, determines whether the vehicle can enter the roundabout based on the acquired information on the roundabout and the information on the targets acquired by the target information acquisition device, and notifies the driver of the result of the determination (S70 to S360), thereby providing driving assistance when entering a roundabout.

[0009] The control unit (driving assistance ECU10) is configured to estimate a first traveling time (T0) until the vehicle reaches an entry position into the roundabout (S70), estimate a second traveling time (T1) until the first other vehicle traveling within the roundabout reaches the entry position (S70), and determine whether or not to enter based on the relationship between the first and second traveling times (S80 to S360).

[0010] Furthermore, according to the present invention, a driving assistance method is provided that provides driving assistance when entering a roundabout, including a step (S10) of acquiring information about a roundabout (110) ahead of the vehicle (102), a step (S30) of acquiring information about targets ahead of the vehicle, and steps (S70 to S360) of determining whether the vehicle can enter the roundabout based on the acquired roundabout information and target information, and notifying the driver of the result of the determination.

[0011] The driving assistance method further includes a step (S70) of estimating a first traveling time (T0) until the vehicle reaches an entry position (Pe) into the roundabout, a step (S70) of estimating a second traveling time (T1) until the earliest other vehicle (A1) traveling within the roundabout reaches the entry position, and steps (S80 to S360) of determining whether or not entry is possible based on the relationship between the first and second traveling times.

[0012] Furthermore, according to the present invention, a driving assistance program is provided that provides driving assistance when entering a roundabout by having an electronic control unit (driving assistance ECU10) mounted on the vehicle execute the following steps: a step (S10) of acquiring information about a roundabout (110) ahead of the vehicle (102); a step (S30) of acquiring information about targets ahead of the vehicle; and steps (S70 to S360) of determining whether the vehicle can enter the roundabout based on the acquired roundabout information and target information, and notifying the driver of the result of the determination.

[0013] The driving assistance program further includes a step (S70) of estimating a first traveling time (T0) until the vehicle reaches an entry position (Pe) into the roundabout, a step (S70) of estimating a second traveling time (T1) until the earliest other vehicle (A1) traveling within the roundabout reaches the entry position, and steps (S80 to S360) of determining whether or not entry is possible based on the relationship between the first and second traveling times.

[0014] According to the above-mentioned driving assistance device, driving assistance method, and driving assistance program, a first traveling time until the vehicle reaches the entry position for the roundabout is estimated, a second traveling time until the first other vehicle traveling within the roundabout reaches the entry position is estimated, and whether or not to enter is determined based on the relationship between the first and second traveling times.

[0015] Therefore, as the host vehicle approaches the entrance position for the roundabout, it is possible to determine whether or not to enter the roundabout based on the relationship between the travel times of the host vehicle and the other vehicle until they reach the entrance position for the roundabout. Therefore, it is possible to determine whether or not to enter the roundabout at an earlier stage than when a determination is made as to whether or not the other vehicle is aggressive when the host vehicle reaches the roundabout and whether or not to enter is made based on the result of that determination.

[0016] [Mode of the Invention] In one aspect of the present invention, the control unit (driving assistance ECU10) is configured to determine (S240) that the host vehicle is permitted to enter the roundabout (110) after the first other vehicle (A1) has passed the entry position when the first traveling time (T0) is greater than the sum (T1+α) of the second traveling time and the first margin time (S150).

[0017] In another aspect of the present invention, the control unit (driving assistance ECU10) is configured to determine (S170) that the host vehicle is permitted to enter the roundabout (110) before the first other vehicle (A1) passes the entry position (Pe) when the first traveling time (T0) is smaller than the difference (T1-β) between the second traveling time and the second margin time (S160).

[0018] In yet another aspect of the present invention, the control unit (driving assistance ECU10) is configured to determine (S190) that the host vehicle cannot enter the roundabout (110) when the first traveling time (T0) is equal to or greater than the difference (T1-β) between the second traveling time and the second margin time and equal to or less than the sum (T1+α) of the second traveling time and the first margin time (S150, S160).

[0019] In still another aspect of the present invention, the control unit (driver assistance ECU 10) is configured to: 0C ) or less, it is determined whether entry is permitted (S120).

[0020] In yet another aspect of the present invention, when the control unit (driving assistance ECU10) determines, based on the acquired roundabout information or the target information acquired by the target information acquisition device, that there is an obstruction (116) in the middle (118) of the roundabout (110) that prevents the target information acquisition device from acquiring information and that there is another vehicle entering a blocked area (120) where the acquisition of information is prevented by the obstruction (S50, S60), the control unit (driving assistance ECU10) is configured to estimate a second traveling time of the other vehicle entering the blocked area based on information acquired by the target information acquisition device before the other vehicle entered the blocked area (S90).

[0021] In yet another aspect of the present invention, the control unit (driving assistance ECU10) is configured to determine (S240) that the host vehicle is permitted to enter the roundabout after the first other vehicle has passed the entry position (Pe) when the first traveling time (T0) is greater than the sum (T1+α) of the second traveling time and the first margin time and there are no other vehicles other than the first other vehicle (A1) in the roundabout (110) (S150, S230).

[0022] In still another aspect of the present invention, when there is another vehicle other than the first other vehicle (A1) in the roundabout (110) (S230), the control unit (driving assistance ECU 10) calculates a third traveling time (T y+1 ) is estimated, and the first running time (T0) is the difference between the third running time and the second margin time (T y+1 -β) (S250), the host vehicle is configured to determine that it is permitted to enter the roundabout after the first other vehicle has passed the entry position and before the second other vehicle has passed the entry position (S260).

[0023] In yet another aspect of the present invention, the host vehicle has an automatic braking device (36), and the control unit (driving assistance ECU 10) is configured to decelerate the host vehicle (S180) using the automatic braking device when the first running time (T0) is equal to or greater than the difference (T1-β) between the second running time and the second margin time and equal to or less than the sum (T1+α) of the second running time and the first margin time (S150, S160), and to determine that the host vehicle is permitted to enter the roundabout after the first other vehicle has passed the entry position (S240) when the first running time becomes greater than the sum of the second running time and the first margin time (S200).

[0024] In yet another aspect of the present invention, the host vehicle has an automatic braking device (36), and the control unit (driver assistance ECU 10) determines whether the first running time (T0) is equal to or greater than the difference (T y+1 -β) (S250), it is determined that the host vehicle cannot enter the roundabout (S280), and the host vehicle is decelerated by the automatic braking device (S270).

[0025] In still another aspect of the present invention, the control unit (driver assistance ECU 10) determines whether the first running time is greater than the sum of the third running time and the first margin time (T y+1 +α) (S290), the host vehicle is configured to determine that it is permitted to enter the roundabout after the first other vehicle and the second other vehicle have passed the entry position (S330).

[0026] In yet another aspect of the present invention, the control unit (driving assistance ECU 10) is configured not to determine whether the host vehicle (102) can enter the roundabout (110) when there is a preceding vehicle between the host vehicle (102) and the roundabout (110) (S20).

[0027] In this application, if there are multiple other vehicles in the roundabout, the "earliest other vehicle" is the other vehicle that takes the shortest time to reach the entrance position of the vehicle into the roundabout. Also, if there is only one other vehicle in the roundabout, the "earliest other vehicle" is that one other vehicle.

[0028] In the above description, to facilitate understanding of the present invention, the names and / or symbols used in the embodiments described below are enclosed in parentheses for the configurations of the invention corresponding to those embodiments. However, each component of the present invention is not limited to the components of the embodiments corresponding to the names and / or symbols enclosed in parentheses. Other objects, features, and attendant advantages of the present invention will be easily understood from the following description of the embodiments of the present invention, which will be given with reference to the drawings. [Brief explanation of the drawings]

[0029] [Figure 1] 1 is a schematic configuration diagram showing an embodiment of a driving assistance device according to the present invention; [Figure 2] 4 is a flowchart corresponding to the first stage of a driving assistance control program in the embodiment. [Figure 3] 10 is a flowchart corresponding to a middle part of a driving assistance control program according to an embodiment. [Figure 4] 10 is a flowchart corresponding to a latter part of a driving assistance control program in the embodiment. [Figure 5] FIG. 1 shows a situation in which the vehicle is approaching a roundabout in a country where vehicles keep on the right side of the road. [Figure 6] This shows a situation where the second other vehicle is located within the shielded area, and the first other vehicle is located outside the shielded area and in front of the second other vehicle. [Figure 7] This shows a situation where the first vehicle is located within the blocked area, and the second vehicle is located behind the first vehicle outside the blocked area. [Figure 8]This shows a situation where there are no other vehicles in the roundabout except for the first other vehicle, and the first other vehicle reaches the entrance position for the roundabout before the own vehicle. [Figure 9] This shows a situation where there are two other vehicles in the roundabout, the distance between the two vehicles is large, and the first other vehicle reaches the entrance position to the roundabout before the vehicle in question. [Figure 10] This shows a situation where there are two other vehicles in the roundabout, the distance between them is small, and the first other vehicle reaches the entrance position to the roundabout before the vehicle in question. [Figure 11] This shows a situation where there are three other vehicles in a roundabout, the distance between the first and second vehicles is small, and the distance between the second and third vehicles is large, and the first vehicle reaches the entrance position to the roundabout before the vehicle in question. [Figure 12] This shows a situation where there are three other vehicles in the roundabout, the distance between these other vehicles is small, and the first other vehicle reaches the entrance position to the roundabout before the vehicle in question. [Figure 13] This shows a situation where there are two other vehicles in the roundabout and the vehicle reaches the entrance position to the roundabout before the other two vehicles. [Figure 14] This shows a situation where there is one other vehicle in the roundabout, and the vehicle and the other vehicle arrive at the entrance to the roundabout at almost the same time. [Figure 15] This shows a situation where there are two other vehicles in the roundabout, the other vehicles are far apart, and the vehicle reaches the entrance position to the roundabout before the first other vehicle. [Figure 16] This shows a situation where there are two other vehicles in the roundabout, the distance between the other vehicles is small, and the vehicle reaches the entrance position to the roundabout before the first other vehicle. DETAILED DESCRIPTION OF THE INVENTION

[0030] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A driving assistance device, a driving assistance method, and a driving assistance program according to embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0031] As shown in Fig. 1, a driving assistance device 100 according to an embodiment of the present invention is applied to a vehicle 102 and includes a driving assistance ECU 10. The vehicle 102 is a vehicle capable of autonomous driving, and includes a drive ECU 20, a brake ECU 30, and a meter ECU 50. The ECU refers to an electronic control unit that includes a microcomputer as its main component. The vehicle 102 will be referred to as the host vehicle 102 as necessary to distinguish it from other vehicles.

[0032] The microcomputer of each ECU includes a CPU, ROM, RAM, read / write non-volatile memory (N / M), and an interface (I / F). The CPU performs various functions by executing instructions (programs, routines) stored in the ROM. Furthermore, these ECUs are interconnected via a Controller Area Network (CAN) 104 to enable data exchange (communication). Therefore, the detected values ​​of sensors (including switches) connected to a specific ECU are transmitted to other ECUs.

[0033] The driving assistance ECU 10 is a central control device that performs driving assistance control such as driving assistance control when entering a roundabout, adaptive cruise control, and lane keeping control. In the embodiment, the driving assistance ECU 10 executes driving assistance control when entering a roundabout in cooperation with other ECUs, as will be described in detail later. In particular, in the embodiment, the driving assistance ECU 10 determines whether or not the host vehicle is allowed to enter the roundabout, notifies the driver of the result, and automatically brakes the host vehicle as necessary, thereby assisting the driver in driving.

[0034] The driving assistance ECU 10 is connected to a camera sensor 12, a radar sensor 14, and a setting operation device 16. The camera sensor 12 and the radar sensor 14 each include a plurality of camera devices and a plurality of radar devices. The camera sensor 12 and the radar sensor 14 function as a target information acquisition device 18 that acquires target information around the vehicle 102.

[0035] Although not shown in the figure, each camera device of the camera sensor 12 includes a camera unit that captures images of the surroundings of the vehicle 102 and a recognition unit that analyzes image data captured by the camera unit to recognize targets such as white lines on the road and other vehicles. The recognition unit supplies information about the recognized targets to the driving assistance ECU 10 at predetermined time intervals.

[0036] Each radar device of the radar sensor 14 uses millimeter wave radio waves to detect the distance between the vehicle and a three-dimensional object, the relative speed between the vehicle and the three-dimensional object, the relative position (direction) of the three-dimensional object with respect to the vehicle, etc., and supplies information representing these at predetermined time intervals to the driving assistance ECU 10. Note that instead of or in addition to the radar sensor 14, a LiDAR (Light Detection And Ranging) may be used.

[0037] The setting operator 16 is arranged in a position that can be operated by the driver, like a steering wheel (not shown in Fig. 1), and is designed to be operated by the driver. Although not shown in Fig. 1, the setting operator 16 includes a driving assistance switch. As will be described in detail later, when the driving assistance switch is on, the driving assistance ECU 10 performs driving assistance when entering a roundabout.

[0038] The drive ECU 20 is connected to a drive device 22 that accelerates the vehicle 102 by applying a driving force to drive wheels 24. The drive ECU 20 normally controls the drive device 22 so that the driving force generated by the drive device 22 changes in response to the driving operation by the driver, and when it receives a command signal from the driving assistance ECU 10, it controls the drive device 22 based on the command signal.

[0039] The braking ECU 30 is connected to a braking device 32 that applies braking force to wheels 34 to decelerate the vehicle 102. The braking ECU 30 normally controls the braking device so that the braking force generated by the braking device 32 changes in response to the braking operation by the driver, and when it receives a command signal from the driving assistance ECU 10, it controls the braking device 32 based on the command signal to perform automatic braking.

[0040] Therefore, the brake ECU 30 and the brake device 32 work together to function as an automatic braking device 36. When braking force is applied to the wheels by cruise control or the like, a brake lamp (not shown in FIG. 1) is turned on.

[0041] A touch panel display 52 that displays the status of control by the driving assistance ECU 10 is connected to the meter ECU 50. The display 52 may be, for example, a multi-information display that displays meters and various information, or may be a display of a navigation device 80 described below. As described below, the display 52 displays the status of driving control when it receives a signal from the driving assistance ECU 10.

[0042] The driving operation sensors 60 and the vehicle condition sensors 70 are also connected to the CAN 104. Information detected by the driving operation sensors 60 and the vehicle condition sensors 70 (referred to as sensor information) is transmitted to the CAN 104. The sensor information transmitted to the CAN 104 can be used appropriately in each ECU. Note that the sensor information may be information from a sensor connected to a specific ECU and transmitted to the CAN 104 from that specific ECU.

[0043] The driving operation sensor 60 includes a driving operation amount sensor that detects the amount of accelerator pedal operation, a braking operation amount sensor that detects the master cylinder pressure or the force applied to the brake pedal, a brake switch that detects whether the brake pedal is operated, a steering angle sensor that detects the steering angle, a steering torque sensor that detects the steering torque, etc.

[0044] The vehicle state sensor 70 detects the vehicle speed V of the vehicle 102. O The sensors include a vehicle speed sensor that detects the vehicle's speed, a longitudinal acceleration sensor that detects the vehicle's longitudinal acceleration, a lateral acceleration sensor that detects the vehicle's lateral acceleration, and a yaw rate sensor that detects the vehicle's yaw rate.

[0045] Furthermore, the navigation device 80 is also connected to the CAN 104. The navigation device 80 includes a GPS receiver that detects the position of the vehicle 102, a storage device that stores map information and road information, and a communication device that acquires the latest map information and road information from an external device. In particular, the road information may include information on the position of a roundabout, the radius of the center of the roundabout, and whether or not there is an obstruction in the middle of the roundabout that prevents the target object information acquisition device 18 from acquiring target object information. Note that the road information does not necessarily include information on whether or not there is an obstruction in the middle of the roundabout, and the determination of whether or not there is an obstruction in the middle of the roundabout may be made based on information acquired by the target object information acquisition device 18. Furthermore, the roundabout information may be acquired by off-vehicle communication, etc.

[0046] In this embodiment, the ROM of the driving assistance ECU 10 stores a driving assistance control program for entering a roundabout that corresponds to the flowcharts shown in Figures 2 and 3. The driving assistance method for entering a roundabout in this embodiment is carried out by executing driving assistance control for entering a roundabout in accordance with the flowcharts shown in Figures 2 and 3.

[0047] <Driving assistance control (Figs. 2 to 4)> Next, the driving assistance control when entering a roundabout in this embodiment will be described with reference to the flowcharts shown in Figures 2 to 4 and Figure 5, which shows a situation in which the vehicle approaches a roundabout in a country where vehicles keep to the right. The driving assistance control according to the flowcharts shown in Figures 2 to 4 is repeatedly executed by the CPU of the driving assistance ECU 10 at predetermined time intervals when the driving assistance switch is on.

[0048] In FIG. 5 , reference numeral 110 denotes a single-lane roundabout where four roads 112A to 112D intersect in a cross shape, and reference numeral 114 denotes the ring road of the roundabout 110. The number of roads intersecting at the roundabout may be any number other than four. Reference numeral 116 denotes an obstruction that prevents the host vehicle 102 from detecting other vehicles traveling within the roundabout, such as a monument or fountain located on an island 118 in the roundabout 110. Reference numeral 120 denotes an obstructed area (hatched area) that is obstructed by the obstruction 116 and cannot be seen from the host vehicle 102. The obstructed area 120 changes depending on the position of the host vehicle 102 relative to the roundabout 110.

[0049] 5 shows three other vehicles A1 to A3 traveling on the ring road 114. It is assumed that the other vehicles A1 to A3 travel along an arc 122 that indicates the center of the ring road 114, and that the radius R (not shown) of the arc 122 can be estimated from information from the navigation device 80.

[0050] First, in step S10, the CPU determines, based on information from the navigation device 80, whether or not there is a single-lane roundabout 110 ahead within a reference distance Lc from the vehicle 102. If a negative determination is made, step S10 is executed again, and if a positive determination is made, the driving assistance control proceeds to step S20.

[0051] The reference distance Lc may be a positive constant, but the vehicle speed V O The value may be variably set according to the vehicle speed of the host vehicle so that the value increases as the vehicle speed increases. Furthermore, even if there is a roundabout within the reference distance Lc ahead of the host vehicle 102, if the roundabout has multiple lanes, a negative determination is made.

[0052] In step S20, the CPU determines whether or not there is a preceding vehicle between the vehicle 102 and the roundabout 110. If a positive determination is made, the process returns to step S10, and if a negative determination is made, the driving assistance control proceeds to step S30.

[0053] In step S30, the CPU determines whether or not there is another vehicle traveling within the roundabout 110, based on the information about the target object acquired by the target object information acquisition device 18. If a positive determination is made, the driving assistance control proceeds to step S50, and if a negative determination is made, the driving assistance control proceeds to step S40.

[0054] In step S40, the CPU outputs a command signal to the meter ECU 50 to cause the display 52 to display "entry permitted," which indicates that the vehicle 102 may enter the roundabout 110.

[0055] In step S50, the CPU determines whether or not there is an obstruction 116 within the roundabout 110 that prevents the target object information acquisition device 18 from acquiring information about other vehicles traveling within the roundabout 110. If a negative determination is made, the driving assistance control proceeds to step S70, and if a positive determination is made, the driving assistance control proceeds to step S60.

[0056] In step S60, the CPU determines whether there is another vehicle that is blocked by the blocking object 116 and therefore information about which cannot be acquired by the target object information acquisition device 18. The determination of whether there is another vehicle that is unable to be acquired information about may be made, for example, by determining whether information about another vehicle that was traveling in front of the blocked area 120 and that was acquired by the target object information acquisition device 18 can no longer be acquired. When a positive determination is made, the driving assistance control proceeds to step S90, and when a negative determination is made, the driving assistance control proceeds to step S70. When a part of the other vehicle enters the blocked area 120, the other vehicle may be determined to be blocked.

[0057] In step S70, the CPU calculates the distance L from the current position of the vehicle 102 to the entrance position Pe of the roundabout 110 based on information from the navigation device 80 and / or information on the target object acquired by the target object information acquisition device 18. O The CPU also estimates the vehicle speed V of the vehicle 102 detected by the vehicle speed sensor.O and distance L O Based on this, a first traveling time T O The first travel time T O When estimating the acceleration G of the vehicle 102 detected by the longitudinal acceleration sensor, O may be taken into consideration.

[0058] In step S70, the CPU estimates the radius R of the arc 122 of the ring road 114 of the roundabout 110 based on information from the navigation device 80. The CPU also calculates, based on the information about the target object acquired by the target object information acquisition device 18, the distance L from the current position of the other vehicle to the entry position Pe of the host vehicle into the roundabout for x other vehicles (x=1, 2...n, n is a positive integer) traveling within the roundabout 110, based on the positions and radii R of the other vehicles. x Furthermore, the CPU estimates the vehicle speed V of the other vehicle based on the information of the target object acquired by the target information acquisition device 18. x Estimate the distance L x and the speed of other vehicles V x Based on this, the travel time T x Estimate.

[0059] In order to identify other vehicles, x is determined in ascending order of distance from the other vehicle to the approach position Pe ahead, and corresponds to the order in which the other vehicle is estimated to arrive at the approach position Pe. Therefore, the x of the other vehicle with the shortest distance to the approach position Pe ahead is 1, and the x of the other vehicle with the longest distance to the approach position Pe ahead is n. Therefore, the smaller x is, the more likely T x Furthermore, based on the information of the target acquired by the target information acquisition device 18, the acceleration G x is estimated, and the travel time T x When estimating the acceleration G of other vehicles, x may be taken into consideration.

[0060] In step S80, the CPU calculates the travel time T y is set to the second travel time T1, that is, the travel time of the other vehicle that has the earliest possibility of arriving at the entrance position Pe to the roundabout.

[0061] In step S90, the CPU calculates the distance L from the current position of the other vehicle to the entrance position Pe of the host vehicle into the roundabout based on the information of the other vehicle acquired by the target information acquisition device 18 before the host vehicle was blocked by the blocking object 116. m Furthermore, the CPU estimates the distance L m and the speed of other vehicles V m Based on this, the travel time T m Based on the target information acquired by the target information acquisition device 18, the acceleration G m is estimated, and the travel time T m When estimating the acceleration G of other vehicles, m may be taken into consideration.

[0062] In step S100, similarly to step S70, the CPU calculates a first travel time T O In addition, the CPU estimates the travel time T x In this step, the smaller x is, the smaller T x is small.

[0063] In step S110, the CPU calculates the travel time T y The second travel time T1 and the estimated travel time T2 of the other vehicle that is likely to arrive at the entrance position Pe to the roundabout earliest are calculated. m Set to the smaller of

[0064] For example, Fig. 6 shows a situation where another vehicle A2 is located within the shaded area 120, another vehicle A1 is located outside the shaded area 120 in front of the other vehicle A2, and there are no other vehicles between the other vehicle A1 and the approach position Pe to the roundabout. In the situation shown in Fig. 6, the second travel time T1 is equal to the estimated travel time T m Since the second travel time T1 is smaller than the travel time T y is set to

[0065] In contrast, Figure 7 shows a situation in which the other vehicle A1 is located within the shielded area 120, the other vehicle A2 is located outside the shielded area 120 behind the other vehicle A1, and there are no other vehicles between the other vehicle A1 and the approach position Pe to the roundabout. In the situation shown in Figure 7, the estimated travel time T m is smaller than the second travel time T1, so the estimated travel time T m is the running time T y is set to

[0066] In step S120, the CPU calculates a first travel time T O is the reference value T OC If a negative determination is made, the driving assistance control returns to step S10, and if a positive determination is made, the driving assistance control proceeds to step S130. OC may be a positive constant, but the vehicle speed V O The vehicle speed V of the host vehicle 102 is set to be larger as O The value may be variably set depending on the

[0067] In step S130, the CPU calculates the running time T y It is determined whether the other vehicle has exited the roundabout 110. If a negative determination is made, the driving assistance control proceeds to step S150, and if a positive determination is made, the driving assistance control proceeds to step S140.

[0068] As for the other vehicle located outside the shaded area 120, as shown by the dashed line of the other vehicle A3 in Fig. 5, when it is determined that the other vehicle has moved from the ring road 114 to a road connected thereto, it may be determined that the other vehicle has exited the roundabout 110. Also, as for the other vehicle located inside the shaded area 120, when it is determined that the traveling time is T m When the other vehicle does not appear at a position beyond the shaded area 120 by the time it should do so, it may be determined that the other vehicle has exited the roundabout 110.

[0069] In step S140, the CPU determines whether the running time is T y The next smallest value is T y The estimated running time is set to T y The next smallest value of T y is set in step S80, T2, and T y If T1 is set to T2 in step S110, the estimated travel time T m is the smaller of T y In step S110, T m If T1 and the running time are set to T m The estimated travel time T of the other vehicle (if any) located in the shielded area 120 behind the other vehicle is m+1 It is the smaller of the two.

[0070] Although not shown in Figure 4, the running time is T y If there is no next smallest value, that is, if it is determined that there is one other vehicle traveling within the roundabout 110 and that one other vehicle has exited the roundabout, the driving assistance control proceeds to step S40.

[0071] In step S150, the CPU calculates the first traveling time T O T y +α, that is, whether the vehicle's running time is T yIt is determined whether or not the other vehicle is permitted to enter the roundabout after passing the entrance position Pe of the roundabout. Note that α is a first margin time which may be a positive constant. If a positive determination is made, the driving assistance control proceeds to step S230, and if a negative determination is made, the driving assistance control proceeds to step S160.

[0072] In step S160, the CPU calculates the first traveling time T O T y -β, that is, whether the running time of the vehicle is T y It is determined whether or not the other vehicle is permitted to enter the roundabout before passing the entrance position Pe of the roundabout. Note that β is a second margin time which may be a positive constant. If a negative determination is made, the driving assistance control proceeds to step S180, and if a positive determination is made, the driving assistance control proceeds to step S170.

[0073] In step S170, the CPU determines that the vehicle 102 may enter the roundabout 110 before the first other vehicle passes the roundabout entry position Pe. Furthermore, the CPU outputs a command signal to the meter ECU 50 to display "May enter before the (first) other vehicle passes" on the display 52.

[0074] In step S180, the CPU outputs a command signal to the automatic braking device 36 via the brake ECU 30 to decelerate the host vehicle 102 at a predetermined deceleration by automatic braking. The predetermined deceleration may be a fixed value set in advance, but may be set based on the estimated running time T O The smaller the estimated travel time T O The value may be variably set depending on the

[0075] In step S190, the CPU determines that the vehicle 102 cannot enter the roundabout 110. Furthermore, the CPU outputs a command signal to the meter ECU 50 to display "enter roundabout not permitted" on the display 52. ​​Note that the display 52 may also display "automatic deceleration in progress," which indicates that the vehicle 102 is being decelerated by automatic braking.

[0076] In step S200, similarly to step S70, the CPU calculates a first travel time T O Furthermore, the CPU estimates the travel time T for the vehicle that is closest to the roundabout 110 and has the shortest estimated travel distance to the roundabout entrance position Pe of the vehicle. y Estimate.

[0077] Furthermore, in step S200, similarly to step S150, the CPU calculates the first traveling time T O T y +α, that is, whether the vehicle's running time is T y The process then determines whether the vehicle is permitted to enter the roundabout after passing the entry position Pe of the roundabout. If a positive determination is made, the deceleration of the host vehicle 102 ends and the driving assistance control proceeds to step S230, and if a negative determination is made, the driving assistance control proceeds to step S210.

[0078] In step S210, the CPU determines whether or not the driver has operated the accelerator pedal based on the amount of operation of the accelerator pedal detected by the driving operation amount sensor of the driving operation sensor 60. If a negative determination is made, the driving assist control returns to step S180, and if a positive determination is made, the deceleration of the host vehicle 102 ends and the driving assist control proceeds to step S220.

[0079] In step S220, the CPU determines that the vehicle 102 may enter the roundabout 110 if the first other vehicle has passed the roundabout entry position Pe. Furthermore, the CPU outputs a command signal to the meter ECU 50 to display on the display 52, "Once the first other vehicle has passed, enter with caution."

[0080] In step S230, the CPU determines whether the running time is T y+1Whether there is another vehicle whose running time is T y If a positive determination is made, the driving assist control proceeds to step S250, and if a negative determination is made, the driving assist control proceeds to step S240.

[0081] In step S240, the CPU determines that the vehicle 102 may enter the roundabout 110 after the first other vehicle has passed the roundabout entry position Pe. Furthermore, the CPU outputs a command signal to the meter ECU 50 to display on the display 52, "Entry permitted after the first other vehicle has passed."

[0082] In step S250, the CPU calculates the first traveling time T O T y+1 -β, that is, whether the running time of the vehicle is T y+1 The system determines whether the other vehicle is permitted to enter the roundabout before passing the roundabout entrance position Pe. If a negative determination is made, the driving assistance control proceeds to step S270, and if a positive determination is made, the driving assistance control proceeds to step S260.

[0083] In step S260, the CPU determines that the vehicle 102 may enter the roundabout 110 after the first other vehicle A1 has passed the roundabout entry position Pe and before the following other vehicle A2 has passed the roundabout entry position Pe. Furthermore, the CPU outputs a command signal to the meter ECU 50 to display on the display 52, "Entry permitted after the first other vehicle has passed and before the following other vehicle has passed."

[0084] In step S270, similarly to step S180, the CPU outputs a command signal to the automatic braking device 36 via the brake ECU 30, thereby decelerating the host vehicle 102 at a predetermined deceleration rate by automatic braking.

[0085] In step S280, the CPU determines that the vehicle 102 cannot enter the roundabout 110. Furthermore, the CPU outputs a command signal to the meter ECU 50 to display "Cannot enter roundabout" on the display 52. ​​Note that the display 52 may also display "Automatic deceleration in progress," which indicates that the vehicle 102 is being decelerated by automatic braking.

[0086] In step S290, similarly to step S70, the CPU calculates a first travel time T O The CPU also estimates a third travel time T y+1 Estimate.

[0087] Furthermore, in step S290, the CPU calculates the first traveling time T O T y+1 +α, that is, whether the vehicle's running time is T y+1 The process then determines whether the second vehicle is permitted to enter the roundabout after passing the entry position Pe for the roundabout. If a positive determination is made, the driving assistance control proceeds to step S320, and if a negative determination is made, the driving assistance control proceeds to step S300.

[0088] In step S300, similar to step S210, the CPU determines whether the driver has operated the accelerator pedal based on the amount of operation of the accelerator pedal detected by the driving operation amount sensor of the driving operation sensor 60. If a negative determination is made, the driving assist control returns to step S270, and if a positive determination is made, the driving assist control proceeds to step S310.

[0089] In step S310, the CPU determines that the vehicle 102 may enter the roundabout 110 if the second vehicle A2 passes the roundabout entry position Pe. Furthermore, the CPU outputs a command signal to the meter ECU 50 to display on the display 52, "Once the second vehicle has passed, enter with caution."

[0090] In step 320, the CPU determines whether the running time is T y+2 Whether there is another vehicle whose running time is T y+1 If a positive determination is made, the driving assistance control proceeds to step S340, and if a negative determination is made, the driving assistance control proceeds to step S330.

[0091] In step S330, the CPU determines that the host vehicle 102 may enter the roundabout 110 after the first other vehicle A1 and the second vehicle A2 have passed the roundabout entry position Pe. Furthermore, the CPU outputs a command signal to the meter ECU 50 to display "entry permitted after second vehicle has passed" on the display 52.

[0092] In step S340, the CPU calculates the first traveling time T O T y+2 -β, that is, whether the running time of the vehicle is T y+2 The system determines whether the other vehicle is permitted to enter the roundabout before passing the roundabout entry position Pe. If a negative determination is made, the driving assistance control proceeds to step S360, and if a positive determination is made, the driving assistance control proceeds to step S350.

[0093] In step S350, the CPU determines that the vehicle 102 may enter the roundabout 110 after the second vehicle has passed the roundabout entry position Pe and before the third vehicle has passed the roundabout entry position Pe. Furthermore, the CPU outputs a command signal to the meter ECU 50 to display on the display 52, "Entry permitted after the second vehicle has passed and before the third vehicle has passed."

[0094] In step S360, the CPU increments y to y + 1. When step S360 is completed, the driving assist control returns to step S270.

[0095] When y is incremented to y+1 in step S360 and steps S270 and after are executed, the ordinal numbers of other vehicles displayed on the display 52 in steps S310, S330, and S350 are increased by 1 for each increment of y.

[0096] For example, when y is incremented once, step S310 displays "Enter with caution once the third vehicle has passed," and step S330 displays "Enter after the third vehicle has passed." Furthermore, step S350 displays "Enter after the third vehicle has passed but before the fourth vehicle has passed."

[0097] <Operation of the embodiment> The operation of the embodiment will be described for various cases where the vehicle 102 approaches a roundabout 110 and the number and positions of other vehicles traveling within the roundabout are different.

[0098] C1: When the first other vehicle arrives at the entrance position to the roundabout before the vehicle (FIGS. 8 to 12). C1-1: When there is only one other vehicle in the roundabout (Figure 8) 8 shows a situation where there are no vehicles other than the other vehicle A1 in the roundabout 110. In this situation, a positive determination is made in step S150, and a negative determination is made in step S230. Therefore, in step S240, "Entry permitted after the (first) other vehicle has passed" is displayed on the display 52, indicating that the host vehicle 102 may enter the roundabout 110 after the other vehicle A1 has passed the entrance position Pe for the roundabout.

[0099] C1-2: When there are two other vehicles in the roundabout and the distance between them is large (Figure 9) 9 shows a situation in which other vehicles A1 and A2 are present in the roundabout 110, the distance between the other vehicles A1 and A2 is large, and the other vehicle A1 reaches the roundabout entry position Pe before the host vehicle 102. In this situation, affirmative determinations are made in steps S150, S230, and S250. Therefore, in step S260, after the other vehicle A1 has passed the roundabout entry position Pe and before the vehicle A2 has passed the roundabout entry position Pe, the display 52 displays "May enter after the first other vehicle has passed and before the subsequent other vehicle has passed," indicating that the host vehicle 102 may enter the roundabout 110.

[0100] C1-3: When there are two other vehicles in the roundabout and the distance between them is small (Figure 10) 10 shows a situation in which vehicles A1 and A2 are present in the roundabout 110 and the distance between the vehicles A1 and A2 is small. In this situation, positive determinations are made in steps S150 and S230, and negative determinations are made in step S250. Therefore, in step S270, the host vehicle 102 is decelerated by automatic braking.

[0101] Furthermore, the running time T O T y+1 If it is greater than +α, a positive determination is made in step S290, and a negative determination is made in step S320. Therefore, in step S330, "Entry permitted after second vehicle passes" is displayed on the display 52, indicating that the host vehicle 102 may enter the roundabout 110 after the second other vehicle A2 has passed the roundabout entry position Pe.

[0102] C1-4: When there are three vehicles in a roundabout, the distance between the first vehicle and the second vehicle is small, and the distance between the second vehicle and the third vehicle is large (Figure 11). 11 shows a situation where there are three other vehicles A1 to A3 in the roundabout 110, with the distance between the other vehicles A1 and A2 being small and the distance between the other vehicles A2 and A3 being large. In this situation, positive determinations are made in steps S150 and S230, negative determinations are made in step S250, and the host vehicle 102 is decelerated in step S270. O T y+1 If it is greater than +α, affirmative decisions are made in steps S290, S320 and S340.

[0103] Because the distance between vehicle A2 and vehicle A3 is large, a positive determination is made in step S340. Therefore, in step S350, the display 52 displays "Entry permitted after the second vehicle has passed and before the third vehicle has passed."

[0104] C1-5: When there are three other vehicles in the roundabout and the distance between them is small (Figure 12) 12 shows a situation where there are three other vehicles A1 to A3 in the roundabout 110, and the distance between these other vehicles is small. In this situation, as in the case of C1-4, positive determinations are made in steps S150 and S230, negative determinations are made in step S250, and the host vehicle 102 is decelerated in step S270. O T y+1 If it becomes larger than +α, an affirmative decision is made in steps S290 and S320, and a negative decision is made in step S340.

[0105] In step S360, y is incremented by 1, and in step S270, the host vehicle 102 is decelerated by automatic braking. O T y+1 If it becomes larger than +α, an affirmative determination is made in step S290, and a negative determination is made in step S320. Therefore, "Entry permitted after the third vehicle has passed" is displayed on the display 52 in step S330.

[0106] C2: When the vehicle reaches the entrance point to the roundabout before the vehicle in front (Figure 13). 13 shows a situation in which there are two other vehicles A1 and A2 in the roundabout 110, and the vehicle 102 reaches the entry position Pe to the roundabout before the other vehicles A1 and A2. Note that the number of other vehicles in the roundabout 110 may be more than two.

[0107] In this situation, a negative determination is made in step S150, an affirmative determination is made in step S160, and "Entry permitted before the first other vehicle has passed" is displayed on the display 52 in step S170.

[0108] C3: When the vehicle and the other vehicle arrive at the entrance to the roundabout at almost the same time (Fig. 14 to Fig. 16). C3-1: When there is only one other vehicle in the roundabout (Figure 14) 14 shows a situation in which one other vehicle A1 is present in the roundabout 110, and the host vehicle 102 and the other vehicle arrive at the roundabout entry position Pe at approximately the same time. In this situation, negative determinations are made in steps S150 and S160, and the host vehicle 102 is decelerated in step S180. O T y If it becomes larger than +α, an affirmative determination is made in step S200, and a negative determination is made in step S230. Therefore, "Entry permitted after the first other vehicle has passed" is displayed on the display 52 in step S240.

[0109] C3-2: When there are two other vehicles in the roundabout and the distance between them is large (Figure 15) 15 shows a situation in which there are other vehicles A1 and A2 in the roundabout 110, the distance between the other vehicles A1 and A2 is large, and the host vehicle 102 and the other vehicle A1 arrive at the entry position Pe at approximately the same time. In this situation, negative determinations are made in steps S150 and S160, and the host vehicle 102 is decelerated in step S180. O T yIf it is greater than +α, affirmative determinations are made in steps S200, S230, and S250. Therefore, in step S260, the display 52 displays "Entry permitted after the first vehicle has passed and before the subsequent vehicle has passed."

[0110] C3-3: When there are two other vehicles in the roundabout and the distance between them is small (Figure 16) 16 shows a situation in which there are two vehicles A1 and A2 in the roundabout 110, the distance between the two vehicles A1 and A2 is small, and the vehicle 102 and the vehicle A1 reach the roundabout entry position Pe at approximately the same time. In this situation, negative determinations are made in steps S150 and S160, and the vehicle 102 is decelerated in step S180. O T y If the travel time T becomes larger than +α, affirmative decisions are made in steps S200 and S230, negative decisions are made in step S250, and the host vehicle 102 is decelerated in step S270. O T y+1 If it becomes larger than +α, an affirmative determination is made in step S290, and a negative determination is made in step S320. Therefore, "Entry permitted after second vehicle has passed" is displayed on the display 52 in step S330.

[0111] C4: When there are no other vehicles in the roundabout In this case, a negative determination is made in step S30. Therefore, the host vehicle 102 is not decelerated, and "Entry permitted" is displayed on the display 52 in step S40.

[0112] <Effects of the present invention> As can be seen from the above description, according to the driving assistance device, the driving assistance method, and the driving assistance program of the present invention, the first traveling time T Ois estimated (S70), a second traveling time T1 until the earliest other vehicle A1 traveling within the roundabout reaches the entry position is estimated (S70), and whether or not entry is possible is determined based on the relationship between the first and second traveling times (S80 to S360).

[0113] Therefore, in the process of the host vehicle 102 approaching the entry position Pe for the roundabout 110, it is possible to determine whether or not to enter the roundabout based on the relationship between the travel times of the host vehicle and the other vehicle until they reach the entry position for the roundabout. Therefore, it is possible to determine whether or not to enter the roundabout at an earlier stage than when a determination is made as to whether or not the other vehicle is aggressive when the host vehicle reaches the roundabout and whether or not to enter is determined based on the result of that determination.

[0114] Furthermore, according to one aspect of the present invention, when the first traveling time T0 is greater than the sum T1+α of the second traveling time and the first margin time (S150), it is determined that the host vehicle can enter the roundabout 110 after the earliest other vehicle A1 has passed the entry position (S240). Therefore, compared to when the first margin time is not taken into consideration, it is possible to more accurately determine that the host vehicle can enter the roundabout after the earliest other vehicle has passed the entry position for the roundabout.

[0115] According to another aspect of the present invention, when the first traveling time T0 is smaller than the difference T1-β between the second traveling time and the second margin time (S160), it is determined that the host vehicle can enter the roundabout 110 before the earliest other vehicle A1 passes the entry position Pe (S170). Therefore, compared to when the second margin time is not taken into consideration, it is possible to more accurately determine that the host vehicle can enter the roundabout before the earliest other vehicle passes the entry position for the roundabout.

[0116] According to yet another aspect of the present invention, when the first traveling time T0 is equal to or greater than the difference T1-β between the second traveling time and the second margin time and equal to or less than the sum T1+α of the second traveling time and the first margin time (S150, S160), it is determined that the host vehicle cannot enter the roundabout 110 (S190). Thus, in a situation where the host vehicle and the foremost other vehicle arrive at the entrance position for the roundabout at almost the same time and there is a risk that the host vehicle will come into close proximity with the foremost other vehicle if it enters the roundabout, it is determined that the host vehicle cannot enter the roundabout, and the risk of the host vehicle coming into close proximity with the foremost other vehicle can be reduced.

[0117] According to yet another aspect of the present invention, the first running time T0 is equal to or less than the reference value T 0C When the following is true, it is determined whether or not the host vehicle can enter the roundabout (S120). Therefore, in a situation where it will take a long time for the host vehicle to reach the roundabout entry position, it is possible to avoid the host vehicle from being unnecessarily early in determining whether or not the host vehicle can enter the roundabout. In particular, it is possible to avoid the host vehicle from being unnecessarily early in deceleration when there is a risk that the host vehicle and the foremost other vehicle will arrive at the roundabout entry position at almost the same time.

[0118] According to yet another aspect of the present invention, when it is determined based on the acquired information on the roundabout 110 or the information on the target object acquired by the target object information acquisition device 18 that there is an obstruction 116 in the middle 118 of the roundabout that prevents the target object information acquisition device from acquiring information and that there is another vehicle entering an obstructed area 120 where the acquisition of information is prevented by the obstruction (S50, S60), a second traveling time of the other vehicle entering the obstructed area is estimated based on the information acquired by the target object information acquisition device before the other vehicle entering the obstructed area (S90).

[0119] Therefore, when there is another vehicle entering an obstructed area where information acquisition is prevented by an obstruction in the middle of a roundabout, it is possible to determine whether or not the vehicle can enter the roundabout based on the relationship between the vehicle and other vehicles, including the other vehicle.

[0120] According to yet another aspect of the present invention, when the first traveling time T0 is greater than the sum T1+α of the second traveling time and the first margin time and there are no other vehicles other than the foremost other vehicle A1 in the roundabout 110 (S150, S230), it is determined that the vehicle can enter the roundabout after the foremost other vehicle has passed the entry position Pe (S240).

[0121] Therefore, compared to when the first margin time is not taken into consideration and when the presence or absence of other vehicles other than the first other vehicle is not determined, it is possible to more accurately determine that the vehicle can enter the roundabout after the first other vehicle has passed the entry position for the roundabout.

[0122] According to yet another aspect of the present invention, when there is another vehicle other than the first vehicle A1 in the roundabout 110 (S230), a third traveling time T y+1 is estimated, and the first running time T0 is the difference T y+1 If it is smaller than -β (S250), it is determined that the host vehicle is permitted to enter the roundabout after the first other vehicle has passed the entry position and before the second other vehicle has passed the entry position (S260).

[0123] Therefore, when there is a second vehicle following the first other vehicle, it is possible to more accurately determine whether the vehicle can enter the roundabout after the first other vehicle has passed the entry position and before the second other vehicle has passed the entry position.

[0124] According to yet another aspect of the present invention, the host vehicle has an automatic braking device 36, and when the first running time T0 is equal to or greater than the difference T1-β between the second running time and the second margin time and equal to or less than the sum T1+α of the second running time and the first margin time (S150, S160), the host vehicle is decelerated by the automatic braking device (S180), and when the first running time becomes greater than the sum of the second running time and the first margin time (S200), it is determined that the host vehicle is permitted to enter the roundabout after the first other vehicle has passed the entry position (S240).

[0125] Therefore, in a situation where the host vehicle and the foremost other vehicle arrive at the entrance position for the roundabout at almost the same time and there is a risk that the host vehicle will come into close contact with the foremost other vehicle when entering the roundabout, the host vehicle can be automatically decelerated. Also, by automatically decelerating the host vehicle, it is possible to more accurately determine when the host vehicle will be able to enter the roundabout after the foremost other vehicle has passed the entrance position.

[0126] According to yet another aspect of the present invention, the host vehicle has an automatic braking device 36, and the first running time T0 is the difference T y+1 If it is equal to or greater than -β (S250), it is determined that the host vehicle cannot enter the roundabout (S280), and the host vehicle is decelerated by the automatic braking device (S270).

[0127] Therefore, in a situation where the first and second other vehicles are in the roundabout and the vehicle is unable to enter the roundabout, this can be accurately determined and the vehicle can be automatically slowed down.

[0128] According to yet another aspect of the present invention, in a situation where the vehicle is being decelerated by an automatic braking device, the first running time is equal to or shorter than the sum T of the third running time and the first margin time. y+1 When it becomes larger than +α (S290), it is determined that the host vehicle is permitted to enter the roundabout after the first other vehicle and the second other vehicle have passed the entry position (S330).

[0129] Therefore, in a situation where there are the first and second other vehicles in a roundabout and the vehicle is slowing down, it is possible to accurately determine when the first and second other vehicles have passed the entry position and the vehicle is able to enter the roundabout.

[0130] According to yet another aspect of the present invention, when there is a preceding vehicle between the host vehicle 102 and the roundabout 110, it is not determined whether the host vehicle can enter the roundabout (S20). When there is a preceding vehicle between the host vehicle 102 and the roundabout 110, whether the host vehicle can enter the roundabout depends on the movement of the preceding vehicle. Therefore, according to the above aspect, it is possible to reduce the risk of inappropriately determining whether the host vehicle can enter the roundabout due to the movement of the preceding vehicle.

[0131] In particular, according to this embodiment, when step S320 is executed and a negative determination is made in step S340, y is incremented to y+1 in step S360, and step S270 and subsequent steps are executed. Therefore, even in a situation where there are three or more other vehicles in the roundabout, it is possible to determine whether or not the host vehicle can enter the roundabout, and to automatically decelerate the host vehicle as necessary.

[0132] Although the present invention has been described in detail above with reference to specific embodiments, it will be apparent to those skilled in the art that the present invention is not limited to the above-described embodiments, and that various other embodiments are possible within the scope of the present invention.

[0133] For example, in the above-described embodiment, the driver is notified whether or not the vehicle can enter the roundabout by displaying the information on the display 52. ​​However, the driver may be notified by voice, or by both a display on the display and voice.

[0134] In the above embodiment, the host vehicle is automatically decelerated when the host vehicle and the first other vehicle arrive at the entrance position to the roundabout at approximately the same time. However, instead of automatically decelerating the host vehicle, the driver may be prompted to decelerate the host vehicle.

[0135] In addition, in the above-described embodiment, the first margin time α and the second margin time β are positive constants, but the length of other vehicles traveling within the roundabout can be estimated, and the longer the length of the other vehicles, the larger the margin time α and the larger the margin time β.

[0136] In addition, in the above-described embodiment, the activation status of the turn signals of other vehicles approaching the entry position into the roundabout is not judged. If the turn signals of the leading vehicle are activated and that vehicle is about to move into the oncoming lane adjacent to the vehicle's own lane 112A, that vehicle may be excluded from other vehicles traveling in the roundabout.

[0137] Furthermore, in the above-described embodiment, if a negative determination is made in step S340, y is incremented to y+1 in step S360, and step S270 and subsequent steps are executed. However, if a negative determination is made in step S340, since there are many other vehicles traveling within the roundabout, a message may be displayed on display 52 indicating that it has not been determined whether the host vehicle can enter the roundabout, and the determination of whether entry is permitted may be terminated.

[0138] Furthermore, in the above-described embodiment, traffic drives on the right side of the road and travels counterclockwise in the roundabout. However, the driving assistance device, the driving assistance method, and the driving assistance program of the present invention may be applied in countries where traffic drives on the left side of the road and travels clockwise in the roundabout. [Explanation of symbols]

[0139] 10... driving assistance ECU, 12... camera sensor, 14... radar sensor, 18... target information acquisition device, 22... drive device, 32... braking device, 36... automatic braking device, 100... driving assistance device, 102... vehicle, 110... roundabout, 116... obstruction, 120... obstructed area

Claims

1. A driving assistance device including a target information acquisition device that acquires information on targets ahead of the vehicle, and a control unit that acquires information on a roundabout ahead of the vehicle, determines whether the vehicle can enter the roundabout based on the acquired information on the roundabout and the information on the targets acquired by the target information acquisition device, and notifies the driver of the result of the determination, thereby providing driving assistance when entering the roundabout, The control unit is configured to estimate a first traveling time until the vehicle reaches an entry position for the roundabout, estimate a second traveling time until the earliest other vehicle traveling within the roundabout reaches the entry position, and determine whether or not to enter the roundabout based on the relationship between the first and second traveling times.

2. 2. The driving assistance device according to claim 1, wherein the control unit is configured to determine that the host vehicle can enter the roundabout after the earliest other vehicle has passed the entry position when the first traveling time is greater than the sum of the second traveling time and a first margin time.

3. 2. The driving assistance device according to claim 1, wherein the control unit is configured to determine that the host vehicle can enter the roundabout before the foremost other vehicle passes the entry position when the first traveling time is smaller than the difference between the second traveling time and a second margin time.

4. 2. The driving assistance device according to claim 1, wherein the control unit is configured to determine that the host vehicle cannot enter the roundabout when the first traveling time is equal to or greater than the difference between the second traveling time and the second margin time and is equal to or less than the sum of the second traveling time and the first margin time.

5. 2. The driving assistance device according to claim 1, wherein the control unit is configured to determine whether or not the entry is permitted when the first traveling time is equal to or less than a reference value.

6. 2. The driving assistance device according to claim 1, wherein when the control unit determines, based on the acquired information about the roundabout or the information about the target object acquired by the target object information acquisition device, that there is an obstruction in the center of the roundabout that prevents the target object information acquisition device from acquiring information and that there is another vehicle entering an obstructed area where acquisition of information is prevented by the obstruction, the control unit estimates the second traveling time of the other vehicle entering the obstructed area based on information acquired by the target object information acquisition device before the other vehicle entered the obstructed area.

7. 3. The driving assistance device according to claim 2, wherein the control unit is configured to determine that the host vehicle is permitted to enter the roundabout after the first other vehicle has passed the entry position when the first traveling time is greater than the sum of the second traveling time and the first margin time and there are no other vehicles other than the first other vehicle in the roundabout.

8. 3. The driving assistance device according to claim 2, wherein the control unit is configured to, when there is a vehicle other than the first other vehicle in the roundabout, estimate a third traveling time until a second other vehicle traveling after the first other vehicle reaches the entry position, and, when the first traveling time is shorter than the difference between the third traveling time and a second margin time, determine that the host vehicle can enter the roundabout after the first other vehicle has passed the entry position and before the second other vehicle has passed the entry position.

9. 5. The driving assistance device according to claim 4, wherein the host vehicle has an automatic braking device, and the control unit is configured to decelerate the host vehicle using the automatic braking device when the first traveling time is equal to or greater than a difference between the second traveling time and a second margin time and equal to or less than a sum of the second traveling time and the first margin time, and to determine that the host vehicle can enter the roundabout after the foremost other vehicle has passed the entry position when the first traveling time becomes greater than the sum of the second traveling time and the first margin time.

10. 9. The driving assistance device according to claim 8, wherein the host vehicle has an automatic braking device, and the control unit is configured to determine that the host vehicle cannot enter the roundabout when the first traveling time is equal to or greater than the difference between the third traveling time and the second margin time, and to decelerate the host vehicle using the automatic braking device.

11. 11. The driving assistance device according to claim 10, wherein the control unit is configured to determine that the host vehicle can enter the roundabout after the first other vehicle and the second other vehicle have passed the entry position when the first traveling time becomes greater than the sum of the third traveling time and the first margin time in a situation where the host vehicle is being decelerated by the automatic braking device.

12. 2. The driving assistance device according to claim 1, wherein the control unit is configured not to determine whether the host vehicle can enter the roundabout when there is a preceding vehicle between the host vehicle and the roundabout.

13. A driving assistance method for providing driving assistance when entering a roundabout, the method comprising: a step of acquiring information about a roundabout ahead of the vehicle; a step of acquiring information about a target object ahead of the vehicle; and a step of determining whether the vehicle can enter the roundabout based on the acquired information about the roundabout and the target object, and notifying the driver of the result of the determination, The driving assistance method further includes the steps of: estimating a first travel time until the vehicle reaches an entry position into the roundabout; estimating a second travel time until the earliest other vehicle traveling within the roundabout reaches the entry position; and determining whether or not entry is possible based on the relationship between the first and second travel times.

14. A driving assistance program that provides driving assistance when entering a roundabout by having an electronic control device mounted on a vehicle execute the following steps: acquiring information about a roundabout ahead of the vehicle; acquiring information about a target object ahead of the vehicle; determining whether the vehicle can enter the roundabout based on the acquired information about the roundabout and the target object, and notifying the driver of the result of the determination; The driving assistance program further includes a step of estimating a first travel time until the vehicle reaches an entry position into the roundabout, a step of estimating a second travel time until the earliest other vehicle traveling within the roundabout reaches the entry position, and a step of determining whether or not entry is possible based on the relationship between the first and second travel times.

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