Driving assistance device, driving assistance method, and driving assistance program

Abstract

To provide a driving assistance device, a driving assistance method, and a driving assistance program that prevent a driver of a vehicle from feeling that driving assistance is unnecessary.SOLUTION: There is provided a driving assistance device 40 configured to executes a driving assistance method and a driving assistance program. The driving assistance device executes the steps of: acquiring information obtained by forward sensors 10, 12, information obtained by side sensors 14, 16, and information related to an own vehicle; providing driving assistance for the own vehicle on the basis of at least one sensor having detected an intersecting target being a moving target a trajectory which intersects with a trajectory of the own vehicle, of the sensors, and a yaw rate of the intersecting target; executing a PB control being a control for braking the own vehicle when the yaw rate of the intersecting target is within a predetermined range and the sensor having detected the intersecting target is at least the forward sensor; and executing an LPB control being a control for braking the own vehicle with a braking force that is smaller compared with the PB control when the yaw rate of the intersecting target is within the predetermined range, and the sensor having detected the intersecting target is only the side sensor.SELECTED DRAWING: Figure 1

Description

[Technical Field]

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

[0002] As described in Patent Document 1, a conventional driving assistance device for a vehicle that recognizes the surrounding environment of the vehicle and provides driving assistance to the driver includes an obstacle determination unit and a driving assistance setting unit. The obstacle determination unit detects obstacles present outside the vehicle and distinguishes between a first obstacle that is visible to the driver of the vehicle and a second obstacle that is difficult to see. The driving assistance setting unit evaluates the risk of collision with the second obstacle as being higher than the risk of collision with the first obstacle and sets driving assistance for collision avoidance for each obstacle. The driving assistance includes audible and visual warnings, forced braking via an automatic brake control device, and avoidance steering via an automatic steering control device. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2010-30513 Summary of the Invention [Problem to be solved by the invention]

[0004] When the driving assistance device described in Patent Document 1 performs forced braking to avoid a collision, the driver of the vehicle suddenly feels the inertial force associated with the deceleration of the vehicle, and may feel that this forced braking is unnecessary.

[0005] The present disclosure aims to provide a driving assistance device, a driving assistance method, and a driving assistance program that prevent a driver of a vehicle from feeling that driving assistance is unnecessary. [Means for solving the problem]

[0006] The invention described in claim 1 is a driving assistance device that includes an acquisition unit (S100) that acquires information obtained by forward sensors (10, 12) that detect targets ahead of a host vehicle (90), information obtained by side sensors (14, 16) that detect targets on the sides of the host vehicle, and information about the host vehicle, and an assistance unit (S108 to S118) that performs driving assistance for the host vehicle based on a sensor that detects an intersection target, which is a moving target whose trajectory intersects with the trajectory of the host vehicle, and the yaw rate of the intersection target, wherein the assistance unit executes a first braking control that is a control for braking the host vehicle when the yaw rate of the intersection target is within a predetermined range and the sensor that detected the intersection target is at least a forward sensor, and executes a second braking control that is a control for braking the host vehicle with a braking force smaller than that of the first braking control when the yaw rate of the intersection target is within the predetermined range and the sensor that detected the intersection target is only a side sensor.

[0007] The invention described in claim 5 is a driving assistance method, which includes: acquiring information obtained by a front sensor (10, 12) that detects a target ahead of a host vehicle (90); information obtained by a side sensor (14, 16) that detects a target on a side of the host vehicle; and information relating to the host vehicle; and performing driving assistance for the host vehicle based on a sensor that has detected an intersecting target, which is a moving target whose trajectory intersects with the trajectory of the host vehicle, and a yaw rate of the intersecting target (S108 to S118), and when the yaw rate of the intersecting target is within a predetermined range and when the sensor that has detected the intersecting target is at least a front sensor, executing a first braking control that is a control for braking the host vehicle; This is a driving assistance method that executes a second braking control, which is a control that brakes the vehicle by reducing the braking force compared to the first braking control, when the yaw rate of the intersecting target is within a predetermined range and the sensor that detected the intersecting target is only a side sensor.

[0008] Furthermore, the invention described in claim 6 is a driving assistance program that causes a driving assistance device to function as an acquisition unit (S100) that acquires information obtained by forward sensors (10, 12) that detect targets ahead of the host vehicle (90), information obtained by side sensors (14, 16) that detect targets on the sides of the host vehicle, and information related to the host vehicle, and an assistance unit (S108 to S118) that performs driving assistance for the host vehicle based on a sensor that detects an intersection target, which is a moving target whose trajectory intersects with the trajectory of the host vehicle, and the yaw rate of the intersection target, and the assistance unit executes a first braking control that is a control for braking the host vehicle when the yaw rate of the intersection target is within a predetermined range and the sensor that detected the intersection target is at least a forward sensor, and executes a second braking control that is a control for braking the host vehicle with a braking force smaller than that of the first braking control when the yaw rate of the intersection target is within the predetermined range and the sensor that detected the intersection target is only a side sensor.

[0009] When the sensor that detects the intersecting target is at least a forward sensor, the intersecting target is a moving target that is visible to the driver of the host vehicle. Therefore, at this time, the driver of the host vehicle recognizes the intersecting target and predicts that automatic braking control will be executed. Therefore, even if the first braking control is executed at this time, the driver of the host vehicle is unlikely to feel that the first braking control is unnecessary. Furthermore, when the sensor that detects the intersecting target is only a side sensor, the intersecting target is a moving target that is difficult for the driver of the host vehicle to recognize. Therefore, at this time, the driver of the host vehicle does not recognize the intersecting target and does not predict that automatic braking control will be executed. Therefore, at this time, by executing the second braking control, which has a smaller braking force than the first braking control, the driver of the host vehicle is unlikely to suddenly feel the inertial force associated with deceleration of the host vehicle. Therefore, the driver of the host vehicle is unlikely to feel that the second braking control is unnecessary. This prevents the driver of the host vehicle from feeling that driving assistance is unnecessary.

[0010] The reference symbols in parentheses attached to each component indicate an example of the correspondence between the component and the specific components described in the embodiments described below. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a configuration diagram of a driving assistance system in which a driving assistance device according to a first embodiment is used. [Figure 2] FIG. 2 is a diagram showing a vehicle whose driving is assisted by a driving assistance device. [Figure 3] FIG. 10 is a diagram showing the relative velocity of the reflection point of a moving target traveling straight ahead. [Figure 4] FIG. 10 is a diagram showing the relative speed of the reflection point of a moving target during a turn. [Figure 5] 1 is a diagram showing reflection points and reference points in XY coordinates. [Figure 6] 1 is a diagram showing reflection points and reference points in XY coordinates. [Figure 7] A diagram showing the relationship between the distance from the reference point to the line passing through the reflection point and the relative rotational speed. [Figure 8] 4 is a flowchart showing processing of the driving assistance device. [Figure 9] FIG. 2 is a diagram showing a host vehicle and an intersecting target; [Figure 10] FIG. 2 is a diagram showing predicted collision positions of the host vehicle and an intersecting object; [Figure 11] FIG. 2 is a diagram showing a first target and a second target. [Figure 12] Graph showing the relationship between time to collision and intersection angle. [Figure 13] FIG. 2 is a diagram showing a host vehicle and an intersecting target; [Figure 14] Graph showing the relationship between time to collision and intersection angle. [Figure 15] 1 is a diagram showing the relationship between the time to collision and the yaw rate of an intersecting target. [Figure 16] 10 is a flowchart showing the processing of a driving assistance device according to a second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, embodiments will be described with reference to the drawings. In the following embodiments, identical or equivalent parts will be denoted by the same reference numerals, and description thereof will be omitted.

[0013] (First embodiment) The driving assistance method and the driving assistance device that executes the driving assistance program according to the present embodiment prevent the driver of the vehicle from feeling that the driving assistance is unnecessary. Specifically, the driving assistance device is used in a driving assistance system for the vehicle. First, the driving assistance system will be described.

[0014] As shown in FIG. 1, the driving assistance system 1 includes a forward sensor 10, a forward camera 12, a left side sensor 14, a right side sensor 16, a vehicle speed sensor 18, a yaw rate sensor 20, an estimation device 30, a driving assistance device 40, and a braking device 50.

[0015] As shown in FIG. 2, the front sensor 10 is disposed, for example, in the center of the front bumper of the host vehicle 90. The front sensor 10 irradiates a search wave, such as a millimeter wave, onto a target ahead of the host vehicle 90. The front sensor 10 receives a reflected wave reflected by the target. As a result, the front sensor 10 detects a target located ahead of the host vehicle 90. The front sensor 10 calculates the relative position, direction, and relative speed of the target with respect to the host vehicle 90 from the irradiated search wave and the reflected wave. The front sensor 10 outputs the calculated data related to the target to an estimation device 30, which will be described later. In FIG. 2, Rf1, which is the range within which the front sensor 10 can detect a target, is indicated by a solid line. Rf1 is symmetrical with respect to the longitudinal axis A of the host vehicle 90. The longitudinal axis A passes through the center of the host vehicle 90 and extends in the longitudinal direction of the host vehicle 90.

[0016] Here, the targets include moving targets and stationary targets. Moving targets include moving vehicles and pedestrians, etc. Stationary targets include stationary vehicles, pedestrians, guardrails, median strips, etc.

[0017] Next, the front camera 12 is disposed, for example, on the rear surface of the inner mirror of the host vehicle 90. Furthermore, the front camera 12 captures an image ahead of the host vehicle 90. The front camera 12 outputs the captured image to an estimation device 30, which will be described later. In FIG. 2, Rf2, which is the range that the front camera 12 can capture, is indicated by a dashed line. Furthermore, Rf2 is symmetrical with respect to the longitudinal axis A.

[0018] The left side sensor 14 is disposed, for example, at the left corner of the front bumper of the host vehicle 90. The left side sensor 14 irradiates a search wave, such as a millimeter wave, onto a target on the left side of the host vehicle 90. The left side sensor 14 receives a reflected wave reflected from the target. As a result, the left side sensor 14 detects a target located on the left side of the host vehicle 90. The left side sensor 14 calculates the relative position, direction, and relative speed of the target with respect to the host vehicle 90 from the irradiated search wave and the reflected wave. The left side sensor 14 outputs the calculated data related to the target to an estimation device 30 (described later). Note that in FIG. 2 , Rl, which is the range within which the left side sensor 14 can detect a target, is indicated by a dashed line. The magnitude of Rl is set larger than the magnitudes of Rf1 and Rf2. Furthermore, Rl partially overlaps with Rf1 and Rf2 in a range from the diagonally forward left of the host vehicle 90 to the front.

[0019] The right side sensor 16 is disposed, for example, at the right corner of the front bumper of the host vehicle 90. The right side sensor 16 emits a search wave, such as a millimeter wave, to a target on the right side of the host vehicle 90. The right side sensor 16 receives a reflected wave reflected by the target. As a result, the right side sensor 16 detects a target located on the right side of the host vehicle 90. The right side sensor 16 calculates the relative position, direction, and relative speed of the target relative to the host vehicle 90 from the emitted search wave and the reflected wave. The right side sensor 16 outputs the calculated data related to the target to the estimation device 30, which will be described later. In FIG. 2 , the range Rr within which the right side sensor 16 can detect targets is indicated by a two-dot chain line. The magnitude of Rr is larger than the magnitudes of Rf1 and Rf2 and is approximately the same as the magnitude of Rl. Furthermore, Rr partially overlaps with Rf1 and Rf2 in a range extending from the diagonally forward right of the host vehicle 90 to the front. Furthermore, Rr partially overlaps with Rl in front of the host vehicle 90.

[0020] 1, the vehicle speed sensor 18 outputs a signal corresponding to the speed of the host vehicle 90 to the driving assistance device 40 (described later).

[0021] The yaw rate sensor 20 outputs a signal corresponding to the yaw rate of the host vehicle 90 to a driving assistance device 40, which will be described later.

[0022] The estimation device 30 is mainly composed of a microcomputer and includes a CPU, ROM, flash memory, RAM, I / O, a communication interface, and a bus line connecting these components. The estimation device 30 executes a program stored in the ROM of the estimation device 30. As a result, the estimation device 30 acquires an image captured by the front camera 12 from the front camera 12. The estimation device 30 also acquires data related to a target from the front sensor 10, the left side sensor 14, and the right side sensor 16. The estimation device 30 also calculates the yaw rate of the target from the acquired data related to the target. The calculation of the yaw rate of the target will be described later. The estimation device 30 then outputs the calculated yaw rate of the target, together with the acquired data related to the target and the captured image, to a driving assistance device 40, which will be described later.

[0023] The driving assistance device 40 is mainly composed of a microcomputer and includes a CPU, ROM, flash memory, RAM, I / O, a communication interface, and a bus line connecting these components. The driving assistance device 40 executes a program stored in the ROM of the driving assistance device 40. As a result, the driving assistance device 40 acquires, from the estimation device 30, the captured image of the front camera 12, data related to targets detected by the front sensor 10, the left side sensor 14, and the right side sensor 16, and the yaw rate of the target calculated by the estimation device 30. The driving assistance device 40 also acquires the speed of the host vehicle 90 from the vehicle speed sensor 18. The driving assistance device 40 also acquires the yaw rate of the host vehicle 90 from the yaw rate sensor 20. The driving assistance device 40 then outputs a signal to a braking device 50 (described later) to perform driving assistance, in this case, automatic braking, based on the acquired captured image, data related to the target, the yaw rate of the target, the vehicle speed, and the yaw rate of the host vehicle 90.

[0024] The braking device 50 applies braking force to the wheels of the host vehicle 90 to brake the host vehicle 90 based on a signal from the driving assistance device 40. In this way, driving assistance is provided to the host vehicle 90.

[0025] The driving assistance system 1 using the driving assistance device 40 of the first embodiment is configured as described above. Next, the calculation of the yaw rate of the target by the estimation device 30 will be described.

[0026] Here, as shown in Fig. 3, when a moving target is moving straight, the relative velocities of multiple reflection points detected by the front sensor 10, the left side sensor 14, or the right side sensor 16 are the same. In contrast, as shown in Fig. 4, when a moving target is turning, the relative velocities of multiple reflection points detected by the front sensor 10, the left side sensor 14, or the right side sensor 16 are different for each reflection point. The reason why the relative velocities of each reflection point are different when the target is turning is because the rotational motion of the target generates a rotational velocity Vω at each reflection point according to the distance from the center of turning.

[0027] Also, here, the distance from the turning center of the target is defined as r. The yaw rate of the target is defined as ω. Furthermore, as shown in Figures 3, 4, 5, and 6, an arbitrary reference point within the target is defined as Pr. The velocity vector of Pr is defined as V_Pr. The Cartesian coordinate system is defined as an XY coordinate system, with the turning center of the target as the origin, the left-right direction of the host vehicle 90 as the X direction, and the front-rear direction of the host vehicle 90 as the Y direction. The position of Pr in the XY coordinate system is defined as x0, y0. The X direction component of V_Pr is defined as Vx0. The Y direction component of V_Pr is defined as Vy0. The reflection point is defined as Pxy. The position of Pxy in the XY coordinate system is defined as x, y. The orientation of the reflection point relative to the host vehicle 90 is defined as θ. The distance from Pr to a straight line that passes through Pxy and has a slope of θ is defined as Dr.

[0028] Also, the X-direction component of the velocity of Pxy is denoted as Vx, the Y-direction component of the velocity of Pxy is denoted as Vy, and the relative velocity of Pxy with respect to the host vehicle 90 is denoted as Vr.

[0029] Vx is expressed as in the following relational expression (1-1). Vy is expressed as in the following relational expression (1-2). Furthermore, Vr is expressed as in the following relational expression (1-3). Furthermore, by substituting the following relational expressions (1-1) and (1-2) into the following relational expression (1-3), Vr is expressed as in the following relational expression (1-4). Furthermore, since x = r × cos θ and y = r × sin θ, by substituting x = r × cos θ and y = r × sin θ into the following relational expression (1-4), Vr is expressed as in the following relational expression (1-5). Furthermore, by transferring Vx0 × cos θ + Vy0 × sin θ on the right side of the following relational expression (1-5) to the left side and interchanging the left and right sides, the following relational expression (1-6) is established.

[0030] Vx=Vx0-ω×(y-y0) ···(1-1) Vy=Vy0+ω×(x-x0) ···(1-2) Vr=Vx×cosθ+Vy×sinθ (1-3) Vr = Vx0 × cosθ + Vy0 × sinθ +(-y×cosθ+x×sinθ)×ω +(y0×cosθ-x0×sinθ)×ω (1-4) Vr = Vx0 × cosθ + Vy0 × sinθ +(y0×cosθ-x0×sinθ)×ω (1-5) (y0×cosθ-x0×sinθ)×ω =Vr-(Vx0×cosθ+Vy0×sinθ) ···(1-6)

[0031] Therefore, in the above relational expression (1-6), the value in parentheses on the left side corresponds to Dr, which is the circumferential positional deviation from Pr to Pxy. Furthermore, the right side is the velocity obtained by subtracting the relative velocity of the velocity vector of Pr at θ from Vr, which corresponds to the rotational relative velocity Vrr, and corresponds to the velocity difference between Pr and Pxy with the circumferential velocity component cancelled out.

[0032] Therefore, the estimation device 30 calculates the yaw rate of the target by calculating Dr and the rotational relative velocity Vrr.

[0033] For example, the estimation device 30 calculates the position of the reference point, i.e., x0, y0, using a tracking method such as extended object tracking. Furthermore, the estimation device 30 calculates the velocity vector of the reference point, i.e., Vx0, Vy0, using a tracking method such as extended object tracking. Note that extended object tracking is a method of modeling a target by assuming that the target has a shape, and estimating the motion state of the target in a time series manner.

[0034] The estimation device 30 also extracts the direction of each reflection point, i.e., θ, from the data relating to the target acquired from the forward sensor 10, the left side sensor 14, and the right side sensor 16. The estimation device 30 also extracts the relative velocity of each reflection point, i.e., Vr, from the data relating to the target acquired from the forward sensor 10, the left side sensor 14, and the right side sensor 16.

[0035] Therefore, the estimation device 30 calculates Dr at each reflection point from the calculated x0, y0 and the extracted θ. The estimation device 30 also calculates the rotational relative velocity Vrr at each reflection point from the calculated Vx0, Vy0 and the extracted θ and Vr. Furthermore, as shown in the relational expression (1-6) and FIG. 7, the slope of the approximate line obtained when Dr and rotational relative velocity Vrr at each reflection point are plotted corresponds to ω. Therefore, the estimation device 30 calculates ω, i.e., the yaw rate of the target, from the calculated Dr and rotational relative velocity Vrr.

[0036] As described above, the estimation device 30 calculates the yaw rate of the target. Next, driving assistance for the host vehicle 90 by executing the program of the driving assistance device 40, in this case automatic braking, will be described with reference to the flowchart of FIG. 8. Note that the program of the driving assistance device 40 is executed, for example, when the ignition or power of the host vehicle 90 is turned on. Also, the period of a series of operations from when the driving assistance device 40 starts processing in step S100 until when the driving assistance device 40 returns to processing in step S100 is defined as the control cycle of the driving assistance device 40.

[0037] In step S100, the driving assistance device 40 acquires various information. Specifically, the driving assistance device 40 acquires an image captured by the forward camera 12 from the estimation device 30. Furthermore, the driving assistance device 40 acquires data related to targets detected by the forward sensor 10, the left side sensor 14, and the right side sensor 16 from the estimation device 30. The driving assistance device 40 also acquires the yaw rate of the target calculated by the estimation device 30 from the estimation device 30. Furthermore, the driving assistance device 40 acquires the vehicle speed of the host vehicle 90 from the vehicle speed sensor 18. The driving assistance device 40 also acquires the yaw rate of the host vehicle 90 from the yaw rate sensor 20.

[0038] Next, in step S102, the driving assistance device 40 determines whether or not either the LPB control or the PB control of the automatic braking control described below is being executed. Note that LPB is an abbreviation for Light Pre-collision Brake. PB is an abbreviation for Pre-collision Brake.

[0039] When either the LPB control or the PB control is being executed, the process of the driving support device 40 returns to step S100, and the currently executed control continues. When neither the LPB control nor the PB control is being executed, or when the execution of either the LPB control or the PB control is completed, the process of the driving support device 40 proceeds to step S104.

[0040] In step S104 following step S102, the driving assistance device 40 determines, based on the information acquired in step S100, whether or not there is an intersecting target around the host vehicle 90. Note that an intersecting target is a moving target whose trajectory intersects with the trajectory of the host vehicle 90.

[0041] For example, the driving assistance device 40 calculates the turning radius of the host vehicle 90 from the vehicle speed and yaw rate of the host vehicle 90 acquired in step S100. Furthermore, the driving assistance device 40 calculates the trajectory of the host vehicle 90 based on the calculated turning radius. The driving assistance device 40 also calculates the transition of the position of the moving target from the captured image and target-related data acquired in step S100. Furthermore, the driving assistance device 40 calculates the trajectory of the moving target based on the calculated transition of the position of the moving target. The driving assistance device 40 also determines whether the calculated trajectory of the host vehicle 90 and the trajectory of the moving target intersect. As a result, the driving assistance device 40 determines whether there is an intersecting target in the vicinity of the host vehicle 90.

[0042] Then, when the trajectory of the host vehicle 90 and the trajectory of the moving target do not intersect, the driving assistance device 40 determines that there is no intersecting target around the host vehicle 90. Then, the processing of the driving assistance device 40 returns to step S100. Also, when the trajectory of the host vehicle 90 and the trajectory of the moving target intersect, the driving assistance device 40 determines that there is an intersecting target around the host vehicle 90. Then, the processing of the driving assistance device 40 proceeds to step S106.

[0043] In step S106 following step S104, the driving assistance device 40 determines whether the intersecting object relative distance Dco is within a predetermined range. As a result, the driving assistance device 40 determines whether there is an extremely high possibility that the host vehicle 90 will collide with the intersecting object. Note that the intersecting object relative distance Dco is the distance from the host vehicle 90 to the intersecting object determined in step S104 in the lateral direction of the host vehicle 90, as shown in FIG. 9 . The lateral direction of the host vehicle 90 corresponds to the left-right direction of the host vehicle 90.

[0044] For example, the driving assistance device 40 extracts the relative position and direction of the intersecting target with respect to the vehicle 90 from the captured image and target-related data acquired in step S100. Furthermore, the driving assistance device 40 calculates the intersecting target relative distance Dco from the extracted relative position and direction of the intersecting target.

[0045] Returning to the flowchart of Fig. 8, when the calculated intersection-target relative distance Dco is within a predetermined range, the driving assistance device 40 determines that there is an extremely high possibility that the host vehicle 90 will collide with the intersection target. Thereafter, the processing of the driving assistance device 40 proceeds to step S112. When the calculated intersection-target relative distance Dco is outside the predetermined range, the driving assistance device 40 determines that there is not an extremely high possibility that the host vehicle 90 will collide with the intersection target. Thereafter, the processing of the driving assistance device 40 proceeds to step S108. Note that the predetermined range for the intersection-target relative distance Dco is set by experiment or simulation so as to determine whether there is an extremely high possibility that the host vehicle 90 will collide with the intersection target.

[0046] In step S108 following step S106, the possibility of the host vehicle 90 colliding with the intersecting object is not very high, but in order to determine whether the host vehicle 90 is likely to collide with the intersecting object, the driving assistance device 40 determines whether the following preconditions are met.

[0047] Here, the precondition is met when all of the following conditions 1 to 7 are met. [Condition 1] The speed of the host vehicle 90 is equal to or greater than a predetermined vehicle speed threshold. [Condition 2] The yaw rate of the host vehicle 90 is less than a predetermined yaw rate threshold value. [Condition 3] The turning radius of the host vehicle 90 is equal to or greater than a predetermined turning radius threshold value. [Condition 4] The yaw rate of the intersecting target is within a predetermined range. [Condition 5] The predicted collision position with the intersecting object on the vehicle 90 is within a predetermined position range. [Condition 6] Condition 5 is satisfied over a plurality of consecutive control periods. [Condition 7] The crossing target is not a ghost.

[0048] The vehicle speed threshold value for Condition 1 is set to a value that satisfies Condition 1 when the host vehicle 90 is not in a stopped state.

[0049] The yaw rate threshold value for condition 2 is set to a value such that condition 2 is met when the host vehicle 90 is traveling in a straight line or a nearly straight line.

[0050] The turning radius threshold value for Condition 3 is set to a value that satisfies Condition 3 when the host vehicle 90 is traveling in a straight line or a nearly straight line. Furthermore, the turning radius threshold value is changed according to the vehicle speed of the host vehicle 90.

[0051] The predetermined range for the yaw rate of the intersection target in Condition 4 is set to a value such that Condition 4 is satisfied when the intersection target is traveling straight or on a trajectory close to that. When the yaw rate of the intersection target is outside the predetermined range, for example, as shown in FIG. 9, if the intersection target is a vehicle, the intersection target is changing lanes by turning left or right. In FIG. 9, the trajectory of the vehicle 90 is indicated by Om, a two-dot chain line, and an arrow. The intersection target is indicated by Tc. Furthermore, the trajectory of the intersection target is indicated by Oc, a two-dot chain line, and an arrow. Furthermore, the left and right turns of the intersection target are indicated by solid lines and arrows.

[0052] Condition 5 is determined when it is determined that the host vehicle 90 and the intersection target will collide when the vehicle maintains its current traveling state and the intersection target moves while maintaining its current moving state. The predicted collision position in Condition 5 is a predicted position where the host vehicle 90 will come into contact with the intersection target when the host vehicle 90 and the intersection target collide.

[0053] Here, as shown in Figure 10, the predicted collision position is defined as Pc. The center of the front bumper of the host vehicle 90 is defined as the start point P0. The right corner of the front bumper of the host vehicle 90 is defined as the right front corner point P1R. The center of the right side of the host vehicle 90 is defined as the right center point P2R. The right corner of the rear bumper of the host vehicle 90 is defined as the right end point P3R. The left corner of the front bumper of the host vehicle 90 is defined as the left front corner point P1L. The center of the left side of the host vehicle 90 is defined as the left center point P2L. The left corner of the rear bumper of the host vehicle 90 is defined as the left end point P3L. In Figure 10, the intersecting target is indicated by Tc.

[0054] Also, on the outer contour of the host vehicle 90, values corresponding to respective positions are preset. Let the value related to the starting point P0 be a0. Let the right front corner point P1R be a1. Let the right center point P2R be a2. Let the right end point P3R be a3. Let the left front corner point P1L be -a1. Let the left center point P2L be -a2. Let the left end point P3L be -a3. Further, let the value related to Pc be ac.

[0055] Also, the relationship a0 < a1 < a2 < a3 holds. Thus, the values related to the outer contour of the host vehicle 90 increase as it goes from the starting point P0 toward the right end point P3R. Further, the relationship -a3 < -a2 < -a1 < a0 holds. Therefore, the values related to the outer contour of the host vehicle 90 decrease as it goes from the starting point P0 toward the left end point P3L.

[0056] And, for example, when Pc is located within the range from the right front corner point P1R to the left front corner point P1L, that is, when a0 < ac < a1, condition 5 is satisfied. Therefore, when Pc is located within the range preset by the starting point P0, the right front corner point P1R, the right center point P2R, the right end point P3R, the left front corner point P1L, the left center point P2L, and the left end point P3L, condition 5 is satisfied. Also, when Pc is not located within the range preset by the starting point P0, the right front corner point P1R, the right center point P2R, the right end point P3R, the left front corner point PIL, the left center point P2L, and the left end point P3L, condition 5 is not satisfied.

[0057] Condition 6 is a condition introduced to ensure that the intersection target is a real target. Further, condition 6 is a condition introduced to ensure the reliability of the intersection target.

[0058] Condition 7 is a condition introduced to ensure that the intersection target is a real target. Also, condition 7 is a condition introduced to ensure the reliability of the intersection target. Note that the ghost of condition 7 is a target that occurs when the position of the target is erroneously determined by the driving support device 40 due to the reflection of electromagnetic waves by a signboard or the like.

[0059] Therefore, the driving assistance device 40 determines whether or not Condition 1 is met using the vehicle speed of the host vehicle 90 acquired in step S100.

[0060] Furthermore, the driving assistance device 40 determines whether or not Condition 2 is met using the yaw rate of the host vehicle 90 acquired in step S100.

[0061] Furthermore, the driving assistance device 40 determines whether or not Condition 3 is met using the turning radius of the host vehicle 90 calculated in step S104.

[0062] Furthermore, the driving assistance device 40 determines whether or not Condition 4 is met using the yaw rate of the intersecting target acquired in steps S100 and S104.

[0063] The driving support device 40 also calculates Pc from the trajectory of the host vehicle 90 and the trajectory of the moving target calculated in step S104, and calculates ac. Then, the driving support device 40 determines whether or not Condition 5 is met based on the calculated ac and the range set by -a3, -a2, -a1, a0, a1, a2, and a3.

[0064] Furthermore, the driving assistance device 40 determines whether or not the condition 6 is met, using the number of times that the above condition 5 is met consecutively.

[0065] Furthermore, the driving assistance device 40 determines whether or not Condition 7 is met by using the transition of the position of the intersecting object calculated in step S104 and a tracking method such as extended object tracking.

[0066] Returning to the flowchart of FIG. 8 , the driving assistance device 40 determines that the preconditions are not met when Condition 1 to Condition 7 are not met. At this time, the driving assistance device 40 determines that there is a low possibility that the host vehicle 90 will collide with the intersecting object. Thereafter, the processing of the driving assistance device 40 returns to step S100. Furthermore, when Condition 1 to Condition 7 are all met, the driving assistance device 40 determines that the preconditions are met. At this time, the driving assistance device 40 determines that there is a high possibility that the host vehicle 90 will collide with the intersecting object. Thereafter, the processing of the driving assistance device 40 proceeds to step S110.

[0067] In step S110 following step S108, the driving support device 40 determines whether the intersecting target determined in step S104 is a moving target detected by only either the left side direction sensor 14 or the right side direction sensor 16. In this way, the driving support device 40 determines the type of the intersecting target. Here, the driving support device 40 determines whether the intersecting target is a first target or a second target.

[0068] When the intersecting target is not a moving target detected only by either the left side direction sensor 14 or the right side direction sensor 16, the intersecting target is detected by at least the forward sensor 10 and the forward camera 12. At this time, the driving support device 40 designates the intersecting target determined in step S104 as the first target, as shown in FIG. 11 . Thereafter, the processing of the driving support device 40 proceeds to step S112. When the intersecting target is a moving target detected only by either the left side direction sensor 14 or the right side direction sensor 16, the driving support device 40 designates the intersecting target determined in step S104 as the second target. Thereafter, the processing of the driving support device 40 proceeds to step S116. In FIG. 11 , the first target is indicated by T1, and the second target is indicated by T2.

[0069] Returning to the flowchart of FIG. 8, step S112 is performed when the intersecting target relative distance Dco is within a predetermined range. At this time, there is an extremely high possibility that the host vehicle 90 will collide with the intersecting target. Alternatively, step S112 is performed when the preconditions of step S108 are met and the intersecting target is the first target. When the intersecting target is the first target, the intersecting target is a moving target detected by at least the front sensor 10 and the front camera 12, and is therefore a moving target visible to the driver of the host vehicle 90. Therefore, when the intersecting target is the first target, the driver of the host vehicle 90 recognizes the intersecting target and therefore predicts that automatic braking control will be executed.

[0070] Therefore, in step S112, the driving assistance device 40 determines whether or not to execute the PB control of the automatic braking control. To this end, the driving assistance device 40 determines whether or not a first time condition is satisfied. Note that, in the PB control, as will be described later, the magnitude of the target deceleration of the host vehicle 90 is relatively large, and the braking force is relatively large.

[0071] Here, the first time condition is met when all of the following conditions F1_1 to F1_4 are met. Note that TTC below is an abbreviation for Time To Collision. TTS below is an abbreviation for Time To Steer. TTB below is an abbreviation for Time To Brake. TCC below is an abbreviation for Time to Conclusive Collision.

[0072] [Condition F1_1] The collision prediction time TTC is equal to or shorter than a predetermined first time threshold TTC_th1. [Condition F1_2] The steering avoidance limit time TTS is equal to or shorter than a predetermined first steering time threshold TTS_th1. [Condition F1_3] The braking-based collision avoidance limit time TTB is equal to or shorter than a predetermined first braking time threshold TTB_th1. [Condition F1_4] The time to collision determination TCC is equal to or less than a predetermined first time to collision threshold TCC_th1.

[0073] The predicted collision time TTC is the predicted time required for the host vehicle 90 to collide with a moving object, and is calculated by dividing the distance to the moving object by the relative speed.

[0074] The steering avoidance limit time TTS is the limit of time within which a collision with a moving object can be avoided by steering operation by the driver, and is determined by calculating the number of seconds from the current time within which a steering operation must be started at a specified lateral acceleration in order to avoid a collision with a moving object.

[0075] The braking avoidance time limit TTB is the limit of time within which a collision with a moving object can be avoided by braking by the driver, and is calculated by calculating the number of seconds from the current time within which a braking operation must be started at a specified deceleration in order to avoid a collision with a moving object.

[0076] The time to collision confirmation TCC is obtained by calculating how many seconds from the present time a moving object must start accelerating or decelerating at a predetermined acceleration or deceleration rate in order to avoid a collision with the host vehicle 90.

[0077] Furthermore, the first time threshold TTC_th1, the first steering time threshold TTS_th1, the first braking time threshold TTB_th1, and the first margin time threshold TCC_th1 are set in advance as follows: Each of the above thresholds is set by experiment, simulation, or the like so that the timing at which the first time condition is satisfied is a timing at which the occupant does not feel that PB control has been started unnecessarily and at which a collision between the host vehicle 90 and a moving object can be appropriately avoided.

[0078] Therefore, the driving assistance device 40 calculates the relative distance of the intersecting object to the host vehicle 90 from the relative position of the intersecting object to the host vehicle 90 acquired in step S100. The driving assistance device 40 also calculates the collision prediction time TTC using the calculated relative distance of the intersecting object to the host vehicle 90 and the relative speed of the intersecting object to the host vehicle 90 acquired in step S100. Furthermore, the driving assistance device 40 calculates the steering avoidance limit time TTS, the braking avoidance limit time TTB, and the collision confirmation margin time TCC.

[0079] Furthermore, the driving support device 40 determines whether or not a condition F1_1 is satisfied using the calculated collision prediction time TTC. Furthermore, the driving support device 40 determines whether or not a condition F1_2 is satisfied using the calculated steering avoidance limit time TTS. Furthermore, the driving support device 40 determines whether or not a condition F1_3 is satisfied using the calculated braking avoidance limit time TTB. Furthermore, the driving support device 40 determines whether or not a condition F1_4 is satisfied using the calculated collision confirmation margin time TCC.

[0080] Then, when the conditions F1_1 to F1_4 are not satisfied, the driving assistance device 40 determines that the first time condition is not satisfied. At this time, the possibility of the host vehicle 90 colliding with the intersecting object is low, and therefore the driving assistance device 40 determines that the PB control should not be executed. Thereafter, the processing of the driving assistance device 40 returns to step S100. Furthermore, when all of the conditions F1_1 to F1_4 are satisfied, the driving assistance device 40 determines that the first time condition is satisfied. At this time, the possibility of the host vehicle 90 colliding with the intersecting object is high, and therefore the driving assistance device 40 determines that the PB control should be executed. Thereafter, the processing of the driving assistance device 40 proceeds to step S114.

[0081] In step S114 following step S112, the driving assistance device 40 executes PB control. Specifically, the driving assistance device 40 outputs a signal to the braking device 50 to execute PB control. As a result, the braking device 50 applies a relatively large braking force to the wheels of the host vehicle 90, thereby relatively increasing the magnitude of the target deceleration of the host vehicle 90. As a result, the host vehicle 90 automatically brakes. At this time, since there is a possibility that the host vehicle 90 will collide with an intersecting object, the driver of the host vehicle 90 is unlikely to feel that the PB control is unnecessary. Alternatively, at this time, since the driver of the host vehicle 90 recognizes the intersecting object and therefore predicts that automatic braking control will be executed, the driver is unlikely to feel that the PB control is unnecessary. Thereafter, the processing of the driving assistance device 40 returns to step S100.

[0082] Next, in step S116 following step S110, the preconditions of step S108 are met and the intersecting target is the second target. At this time, the intersecting target is a moving target detected by only either the left side direction sensor 14 or the right side direction sensor 16, and is therefore a moving target that is difficult for the driver of the host vehicle 90 to see. For this reason, at this time, the driver of the host vehicle 90 does not recognize the intersecting target and does not predict that automatic braking control will be executed.

[0083] Therefore, in step S116 following step S110, the driving assistance device 40 determines whether or not to execute LPB control, which is an automatic braking control. To this end, the driving assistance device 40 determines whether or not a second time condition is satisfied. As will be described later, in LPB control, the magnitude of the target deceleration of the host vehicle 90 is smaller than in PB control, and the braking force is also smaller than in PB control. Furthermore, in LPB control, the jerk is gentler than in PB control. The jerk is the rate of change of the deceleration until the deceleration reaches the target deceleration.

[0084] Here, the second time condition is met when all of the following conditions F2_1 to F2_4 are met.

[0085] [Condition F2_1] The collision prediction time TTC is equal to or less than a predetermined second time threshold TTC_th2. [Condition F2_2] The steering avoidance limit time TTS is equal to or less than a predetermined second steering time threshold TTS_th2. [Condition F2_3] The braking-based collision avoidance limit time TTB is equal to or less than a predetermined second braking time threshold TTB_th2. [Condition F2_4] The time to collision determination TCC is equal to or less than a predetermined second time to collision threshold TCC_th2.

[0086] Furthermore, the second time threshold TTC_th2, the second steering time threshold TTS_th2, the second braking time threshold TTB_th2, and the second margin time threshold TCC_th2 are set in advance as follows: The second time threshold TTC_th2 is greater than the first time threshold TTC_th1. The second steering time threshold TTS_th2 is greater than the first steering time threshold TTS_th1. The second braking time threshold TTB_th2 is greater than the first braking time threshold TTB_th1. The second margin time threshold TCC_th2 is greater than the first margin time threshold TCC_th1. For these reasons, the second time condition is satisfied at an earlier timing than the first time condition. Therefore, the LPB control is started at an earlier timing than the PB control.

[0087] Therefore, the driving assistance device 40 calculates the relative distance of the intersecting object to the host vehicle 90 from the relative position of the intersecting object to the host vehicle 90 acquired in step S100. The driving assistance device 40 also calculates the collision prediction time TTC using the calculated relative distance of the intersecting object to the host vehicle 90 and the relative speed of the intersecting object to the host vehicle 90 acquired in step S100. Furthermore, the driving assistance device 40 calculates the steering avoidance limit time TTS, the braking avoidance limit time TTB, and the collision confirmation margin time TCC.

[0088] Furthermore, the driving support device 40 determines whether or not a condition F2_1 is satisfied using the calculated collision prediction time TTC. Furthermore, the driving support device 40 determines whether or not a condition F2_2 is satisfied using the calculated steering avoidance limit time TTS. Furthermore, the driving support device 40 determines whether or not a condition F2_3 is satisfied using the calculated braking avoidance limit time TTB. Furthermore, the driving support device 40 determines whether or not a condition F2_4 is satisfied using the calculated collision confirmation margin time TCC.

[0089] Then, when the conditions F2_1 to F2_4 are not satisfied, the driving assistance device 40 determines that the second time condition is not satisfied. At this time, the possibility of the host vehicle 90 colliding with the second target of the intersecting object is low, and therefore the driving assistance device 40 determines that the LPB control should not be executed. Thereafter, the processing of the driving assistance device 40 returns to step S100. Furthermore, when the conditions F2_1 to F2_4 are all satisfied, the driving assistance device 40 determines that the first time condition is satisfied. At this time, the possibility of the host vehicle 90 colliding with the second target of the intersecting object is high, and therefore the driving assistance device 40 determines that the LPB control should be executed. Thereafter, the processing of the driving assistance device 40 proceeds to step S118.

[0090] In step S118 following step S116, the driving assistance device 40 executes LPB control. Specifically, the driving assistance device 40 outputs a signal to the braking device 50 to execute LPB control. As a result, the braking device 50 applies a braking force to the wheels of the host vehicle 90 that is smaller than that in PB control, thereby reducing the magnitude of the target deceleration of the host vehicle 90 compared to that in PB control and making the jerk of the host vehicle 90 gentler compared to that in PB control. As a result, the host vehicle 90 automatically brakes. At this time, the driver of the host vehicle 90 does not recognize an intersecting target and does not predict that automatic braking control will be executed, and therefore is unlikely to suddenly feel the inertial force associated with the deceleration of the host vehicle 90. As a result, the driver of the host vehicle 90 is unlikely to feel that LPB control is unnecessary. Furthermore, in LPB control, the magnitude of the braking force applied to the host vehicle 90 is relatively small, so the distance from the start of LPB control to the stop of the host vehicle 90 is relatively long. However, since the LPB control is started at an earlier timing than the PB control, a collision between the host vehicle 90 and the intersecting object is appropriately avoided. After that, the processing of the driving assistance device 40 returns to step S100.

[0091] As described above, the driving assistance device 40 performs driving assistance, in this case, automatic braking, for the host vehicle 90. Next, it will be explained how the driving assistance device 40 prevents the driver of the host vehicle 90 from feeling that the driving assistance is unnecessary.

[0092] Here, when the driving assistance device described in Patent Document 1 performs forced braking to avoid a collision, the driver of the vehicle suddenly feels the inertial force associated with the deceleration of the vehicle, and may feel that this forced braking is unnecessary.

[0093] In contrast, the driving assistance device 40 of this embodiment serves as an acquisition unit that acquires information obtained by the forward sensor 10 and the front camera 12, information obtained by the left side side sensor 14 and the right side side sensor 16, and information related to the host vehicle 90. The driving assistance device 40 also serves as an assistance unit that provides driving assistance for the host vehicle 90 based on the sensors that have detected intersecting targets and the yaw rates of the intersecting targets. The information obtained by the forward sensor 10, the front camera 12, the left side side sensor 14, and the right side side sensor 16 includes the relative position of the target with respect to the host vehicle 90, the direction and relative speed of the target, the yaw rate and captured images of the target, etc. The information related to the host vehicle 90 includes the vehicle speed and yaw rate of the host vehicle 90, etc.

[0094] Furthermore, the driving assistance device 40 performs PB control when the yaw rate of the intersecting target is within a predetermined range and the sensors that detected the intersecting target are at least the forward sensor 10 and the forward camera 12. Also, the driving assistance device 40 performs LPB control when the yaw rate of the intersecting target is within a predetermined range and the sensors that detected the intersecting target are only either the left side sensor 14 or the right side sensor 16. The PB control corresponds to the first braking control. The LPB control corresponds to the second braking control.

[0095] When the sensors that detect the intersecting target are at least the forward sensor 10 and the forward camera 12, the intersecting target is a moving target that is visible to the driver of the host vehicle 90. Therefore, at this time, the driver of the host vehicle 90 recognizes the intersecting target and predicts that automatic braking control will be executed. Therefore, even if PB control is executed at this time, the driver of the host vehicle 90 is unlikely to feel that PB control is unnecessary. Furthermore, when the sensor that detects the intersecting target is only one of the left side sensor 14 and the right side sensor 16, the intersecting target is a moving target that is difficult for the driver of the host vehicle 90 to recognize. Therefore, at this time, the driver of the host vehicle 90 does not recognize the intersecting target and does not predict that automatic braking control will be executed. Therefore, at this time, LPB control, which has a smaller braking force than PB control, is executed, so the driver of the host vehicle 90 is unlikely to suddenly feel the inertial force associated with deceleration of the host vehicle 90. Therefore, the driver of the host vehicle 90 is unlikely to feel that LPB control is unnecessary. This prevents the driver of the vehicle 90 from feeling that the driving assistance is unnecessary.

[0096] In addition, in the preconditions of step S108, the condition that the intersection angle θc is within a predetermined range may be set as a condition instead of the yaw rate of the intersecting target being within a predetermined range as in condition 4. The intersection angle θc is the angle formed by the velocity vector of the host vehicle 90 and the velocity vector of the intersecting target.

[0097] When the intersection angle θc is used, for example, if the predetermined range for the intersection angle θc is 80° to 100°, the driving assistance device 40 can determine whether the intersecting object is going straight, turning left, or turning right when the intersection angle θc is about 90°, as shown in Figures 9 and 12. Therefore, when the intersection angle θc is about 90°, the driving assistance device 40 can appropriately perform PB control and LPB control.

[0098] However, as shown in Figures 13 and 14, when the intersection angle θc is 45° or 135°, for example, if the intersecting target approaches the host vehicle 90 obliquely, the intersection angle θc falls outside the predetermined range. As a result, the driving assistance device 40 cannot determine whether the intersecting target is going straight, turning left, or turning right. Therefore, when the intersection angle θc is used, the driving assistance device 40 may not be able to appropriately perform the PB control and the LPB control. In Figure 13, the trajectory of the host vehicle 90 is indicated by Om, a two-dot chain line, and an arrow. The intersecting target is indicated by Tc. The trajectory of the intersecting target is indicated by Oc, a two-dot chain line, and an arrow.

[0099] In contrast to this, the driving support device 40 of this embodiment uses the yaw rate of the intersecting target in condition 4.

[0100] Here, when the intersecting target moves straight, the yaw rate of the intersecting target is zero regardless of the intersection angle θc, as shown in Fig. 15. Furthermore, when the intersecting target turns left or right, the yaw rate of the intersecting target changes. In Fig. 15, the yaw rate of the intersecting target is indicated by ω.

[0101] Therefore, the driving assistance device 40 can determine whether the intersecting object will go straight, turn left, or turn right by using the yaw rate of the intersecting object in condition 4. Therefore, the driving assistance device 40, which uses the yaw rate of the intersecting object, can appropriately perform PB control and LPB control regardless of the intersecting angle θc.

[0102] Furthermore, the driving assistance device 40 of the first embodiment also provides the following effects.

[0103] [1] The driving support device 40 executes the PB control when the intersecting target relative distance Dco is within a predetermined range.

[0104] When the intersecting target relative distance Dco is within a predetermined range, there is an extremely high possibility that the host vehicle 90 will collide with the intersecting target. Therefore, the above processing makes it easy to appropriately avoid a collision between the host vehicle 90 and the moving target.

[0105] [2] When the yaw rate of the intersecting object is within a predetermined range, and the sensors that detected the intersecting object are at least the forward sensor 10 and the forward camera 12. In this case, when the vehicle speed of the host vehicle 90 is equal to or greater than the vehicle speed threshold, and the yaw rate of the host vehicle 90 is less than the yaw rate threshold, and the turning radius of the host vehicle 90 is equal to or greater than the turning radius threshold. In this case, the driving assistance device 40 executes PB control. Furthermore, when the yaw rate of the intersecting object is within a predetermined range, and the sensors that detected the intersecting object are only either the left side sensor 14 or the right side sensor 16. In this case, when the vehicle speed of the host vehicle 90 is equal to or greater than the vehicle speed threshold, and the yaw rate of the host vehicle 90 is less than the yaw rate threshold, and the turning radius of the host vehicle 90 is equal to or greater than the turning radius threshold. In this case, the driving assistance device 40 executes LPB control.

[0106] This limits the situation to when the host vehicle 90 is traveling straight, making it easier to appropriately avoid a collision between the host vehicle 90 and a moving target.

[0107] [3] The driving support device 40 executes PB control when the collision prediction time TTC is equal to or less than a first time threshold TTC_th1. Furthermore, the driving support device 40 executes LPB braking control when the collision prediction time TTC is equal to or less than a second time threshold TTC_th2 that is greater than the first time threshold TTC_th1.

[0108] This makes it easier to appropriately avoid a collision between the host vehicle 90 and a moving target, regardless of whether the PB control or the LPB control is executed.

[0109] (Second embodiment) In the second embodiment, the processing of the driving support device 40 differs from that of the first embodiment, as shown in the flowchart of Fig. 16. Other than this, the second embodiment is similar to the first embodiment.

[0110] Specifically, in step S108, the driving support device 40 determines only whether the above-mentioned condition 4 is satisfied, instead of determining whether the prerequisite condition is satisfied. That is, the driving support device 40 determines only whether the yaw rate of the intersecting target is within a predetermined range.

[0111] When the yaw rate of the intersecting target is not within the predetermined range, the process of the driving support device 40 returns to step S100. When the yaw rate of the intersecting target is within the predetermined range, the process of the driving support device 40 proceeds to step S110. The process from step S110 onwards is the same as in the first embodiment.

[0112] As described above, the driving assistance device 40 of the second embodiment performs the processing. In the second embodiment, the same effects as in the first embodiment are achieved.

[0113] (Other embodiments) The present disclosure is not limited to the above-described embodiments, and appropriate modifications can be made to the above-described embodiments. Furthermore, it goes without saying that the elements constituting the embodiments in the above-described embodiments are not necessarily essential unless they are specifically stated as essential or are considered to be clearly essential in principle.

[0114] The acquisition unit, support unit, and methods described herein may be implemented by a special-purpose computer configured with a processor and memory programmed to perform one or more functions embodied in a computer program. Alternatively, the acquisition unit, support unit, and methods described herein may be implemented by a special-purpose computer configured with a processor configured with one or more dedicated hardware logic circuits. Alternatively, the acquisition unit, support unit, and methods described herein may be implemented by one or more special-purpose computers configured with a processor and memory programmed to perform one or more functions in combination with a processor configured with one or more hardware logic circuits. Furthermore, the computer program may be stored as instructions executed by a computer on a computer-readable non-transitory storage medium.

[0115] In the above embodiments, millimeter waves are used as the probe waves, but the probe waves are not limited to millimeter waves and may be infrared waves, ultrasonic waves, or the like.

[0116] In each of the above embodiments, the front sensor 10, the left side sensor 14, and the right side sensor 16 are search wave sensors that use search waves such as millimeter waves. However, the front sensor 10, the left side sensor 14, and the right side sensor 16 are not limited to being search wave sensors, and may be image sensors such as cameras.

[0117] In each of the above embodiments, the driving assistance system 1 includes a front camera 12. The driving assistance system 1 may include, instead of the front camera 12, a sensor other than the front sensor 10, such as a search wave sensor that uses search waves such as millimeter waves, infrared rays, and ultrasonic waves.

[0118] In each of the above embodiments, the estimation device 30 calculates the yaw rate of the target using the reflected wave of the probe wave. However, the estimation device 30 is not limited to using the reflected wave of the probe wave. For example, the estimation device 30 may calculate the yaw rate of the target using the optical flow of an image captured by a camera. Note that the optical flow is a movement vector of feature points in the image.

[0119] (Aspects of the present disclosure) [Point 1] A driving assistance device, an acquisition unit (S100) that acquires information obtained by a front sensor (10, 12) that detects a target ahead of a host vehicle (90), information obtained by a side sensor (14, 16) that detects a target on a side of the host vehicle, and information about the host vehicle; a support unit (S108 to S118) that provides driving support for the host vehicle based on a sensor that detects an intersecting target, which is a moving target whose trajectory intersects with the trajectory of the host vehicle, and a yaw rate of the intersecting target; Equipped with The support unit When the yaw rate of the intersecting target is within a predetermined range and the sensor that detected the intersecting target is at least the front sensor, a first braking control is executed, which is a control for braking the host vehicle; When the yaw rate of the intersecting target is within a predetermined range and the sensor that detected the intersecting target is only the side sensor, a driving assistance device that executes a second braking control that brakes the vehicle by reducing the braking force compared to the first braking control. [Point 2] The driving assistance device according to Aspect 1, wherein the assistance unit executes the first braking control when a distance (Dco) from the host vehicle to the intersecting object in the left-right direction of the host vehicle is within a predetermined range. [Point 3] The support unit executes the first braking control when the vehicle speed of the host vehicle is equal to or greater than a vehicle speed threshold, the yaw rate of the host vehicle is less than a yaw rate threshold, the turning radius of the host vehicle is equal to or greater than a turning radius threshold, the yaw rate of the intersecting target is within a predetermined range, and the sensor that detected the intersecting target is at least the front sensor; The driving assistance device according to aspect 1 or 2, wherein the second braking control is executed when the vehicle speed of the host vehicle is equal to or greater than the vehicle speed threshold, the yaw rate of the host vehicle is less than the yaw rate threshold, the turning radius of the host vehicle is equal to or greater than the turning radius threshold, the yaw rate of the intersecting object is within a predetermined range, and the sensor that detected the intersecting object is only the lateral sensor. [Point 4] The support unit executes the first braking control when a yaw rate of the intersecting object is within a predetermined range, when the sensor that detected the intersecting object is at least the front sensor, and when a collision prediction time (TTC) that is a time that is predicted to be required until the host vehicle collides with the intersecting object is equal to or less than a first time threshold (TTC_th1); A driving assistance device according to any one of aspects 1 to 3, which executes the second braking control when the yaw rate of the intersecting target is within a predetermined range, when the sensor that detected the intersecting target is only the side sensor, and when the collision prediction time is equal to or less than a second time threshold (TTC_th2) that is greater than the first time threshold. [Point 5] A driving assistance method, acquiring information obtained by a front sensor (10, 12) detecting a target ahead of a host vehicle (90), information obtained by a side sensor (14, 16) detecting a target on a side of the host vehicle, and information relating to the host vehicle; performing driving assistance for the host vehicle based on a sensor that detects an intersecting target, which is a moving target whose trajectory intersects with the trajectory of the host vehicle, and a yaw rate of the intersecting target (S108 to S118); Including, When the yaw rate of the intersecting target is within a predetermined range and the sensor that detected the intersecting target is at least the front sensor, a first braking control is executed, which is a control for braking the host vehicle; A driving assistance method that executes a second braking control, which is a control that brakes the vehicle by reducing the braking force compared to the first braking control, when the yaw rate of the intersecting target is within a predetermined range and the sensor that detected the intersecting target is only the side sensor. [Point 6] A driving assistance program, Driving assistance devices, an acquisition unit (S100) that acquires information obtained by a front sensor (10, 12) that detects a target ahead of a host vehicle (90), information obtained by a side sensor (14, 16) that detects a target on a side of the host vehicle, and information about the host vehicle; a support unit (S108 to S118) that provides driving support for the host vehicle based on a sensor that detects an intersecting target, which is a moving target whose trajectory intersects with the trajectory of the host vehicle, and the yaw rate of the intersecting target; It functions as The support unit When the yaw rate of the intersecting target is within a predetermined range and the sensor that detected the intersecting target is at least the front sensor, a first braking control is executed, which is a control for braking the host vehicle; A driving assistance program that executes a second braking control, which is a control for braking the host vehicle by reducing the braking force compared to the first braking control, when the yaw rate of the intersecting target is within a predetermined range and when the sensor that detected the intersecting target is only the side sensor. [Explanation of symbols]

[0120] 10 Front Sensor 12 Front camera 14 Left side camera 16 Right side camera 18 Vehicle speed sensor 20 Yaw rate sensor 30 Estimation device 40 Driving assistance devices 50 Braking device 90 Vehicle

Claims

1. A driving assistance device, an acquisition unit (S100) that acquires information obtained by a front sensor (10, 12) that detects a target ahead of a host vehicle (90), information obtained by a side sensor (14, 16) that detects a target on a side of the host vehicle, and information about the host vehicle; a support unit (S108 to S118) that provides driving support for the host vehicle based on a sensor that detects an intersecting target, which is a moving target whose trajectory intersects with the trajectory of the host vehicle, and a yaw rate of the intersecting target; Equipped with The support unit When the yaw rate of the intersecting target is within a predetermined range and the sensor that has detected the intersecting target is at least the front sensor, a first braking control is executed, which is a control for braking the host vehicle; When the yaw rate of the intersecting target is within a predetermined range and the sensor that detected the intersecting target is only the side sensor, a driving assistance device that executes a second braking control, which is a control that brakes the vehicle by reducing the braking force compared to the first braking control.

2. The driving assistance device according to claim 1 , wherein the assistance unit executes the first braking control when a distance (Dco) from the host vehicle to the intersecting object in the left-right direction of the host vehicle is within a predetermined range.

3. The support unit executes the first braking control when the vehicle speed of the host vehicle is equal to or greater than a vehicle speed threshold, the yaw rate of the host vehicle is less than a yaw rate threshold, the turning radius of the host vehicle is equal to or greater than a turning radius threshold, the yaw rate of the intersecting target is within a predetermined range, and the sensor that detected the intersecting target is at least the front sensor, 3. The driving assistance device according to claim 1, wherein the second braking control is executed when the vehicle speed of the host vehicle is equal to or greater than the vehicle speed threshold, the yaw rate of the host vehicle is less than the yaw rate threshold, the turning radius of the host vehicle is equal to or greater than the turning radius threshold, the yaw rate of the intersecting object is within a predetermined range, and the sensor that detected the intersecting object is only the lateral sensor.

4. The support unit executes the first braking control when a yaw rate of the intersecting target is within a predetermined range, when the sensor that detected the intersecting target is at least the front sensor, and when a predicted time to collision (TTC) that is a time that is predicted to be required until the host vehicle collides with the intersecting target is equal to or less than a first time threshold (TTC_th1); 3. The driving assistance device according to claim 1, wherein the second braking control is executed when the yaw rate of the intersecting target is within a predetermined range, when the sensor that detected the intersecting target is the side sensor only, and when the collision prediction time is equal to or less than a second time threshold (TTC_th2) that is greater than the first time threshold.

5. A driving assistance method, Acquiring information obtained by a front sensor (10, 12) that detects a target ahead of a host vehicle (90), information obtained by a side sensor (14, 16) that detects a target on a side of the host vehicle, and information relating to the host vehicle; providing driving assistance for the host vehicle based on a sensor that detects an intersecting target, which is a moving target whose trajectory intersects with the trajectory of the host vehicle, and a yaw rate of the intersecting target (S108 to S118); Including, When the yaw rate of the intersecting target is within a predetermined range and the sensor that has detected the intersecting target is at least the front sensor, a first braking control is executed, which is a control for braking the host vehicle; A driving assistance method that executes a second braking control, which is a control that brakes the vehicle by reducing the braking force compared to the first braking control, when the yaw rate of the intersecting target is within a predetermined range and the sensor that detected the intersecting target is only the side sensor.

6. A driving assistance program, Driving assistance devices, an acquisition unit (S100) that acquires information obtained by a front sensor (10, 12) that detects a target ahead of a host vehicle (90), information obtained by a side sensor (14, 16) that detects a target on a side of the host vehicle, and information about the host vehicle; a support unit (S108 to S118) that provides driving support for the host vehicle based on a sensor that detects an intersecting target, which is a moving target whose trajectory intersects with the trajectory of the host vehicle, and the yaw rate of the intersecting target; It functions as The support unit When the yaw rate of the intersecting target is within a predetermined range and the sensor that has detected the intersecting target is at least the front sensor, a first braking control is executed, which is a control for braking the host vehicle; A driving assistance program that executes a second braking control, which is a control that brakes the vehicle by reducing the braking force compared to the first braking control, when the yaw rate of the intersecting target is within a predetermined range and the sensor that detected the intersecting target is only the side sensor.

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