Vehicle control device, vehicle control method, and program thereof

Abstract

To prevent a vehicle itself from approaching a preceding vehicle too much and reduce a possibility of a driver feeling collision avoidance control cumbersome in the case of executing the control.SOLUTION: An operation support ECU 20 performs: inhibiting execution of steering avoidance control in a case where an indicating direction indicated by a direction indicator of a preceding vehicle is the same as an avoidance-planning direction by the steering avoidance control; setting a steering avoidance control start condition at a first start condition in a case where a state of the direction indicator the preceding vehicle is not in a state of indicating a direction; and setting the steering avoidance control start condition at a second start condition in a case where the indicating direction is different from the avoidance-planning direction. The first and second start conditions are determined so that an inter-vehicular distance between the preceding vehicle and a vehicle itself SV at a time point when the second start condition can be possibly established is shorter than an inter-vehicular distance at a time point when the first start condition can possibly be established.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a vehicle control device, a vehicle control method, and a program therefor that execute control to avoid a collision between a vehicle (host vehicle) and another vehicle (forward vehicle) located in front of the host vehicle. [Background technology]

[0002] One conventional collision avoidance assistance device, when there is a possibility that the vehicle will collide with an obstacle in front of the vehicle, and an avoidance route exists that allows the vehicle to avoid collision with the obstacle and without colliding with other objects, automatically steers the vehicle so that the vehicle moves along the avoidance route (see Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2017-43262 A Summary of the Invention

[0004] Incidentally, there is a case where the obstacle in front of the vehicle is a vehicle ahead, and the direction indicator of the vehicle ahead is operating (flashing) to indicate either the left or right direction (hereinafter, sometimes referred to as the "instructed direction"). In this case, a situation may occur where the indicated direction is different from the direction in which the vehicle ahead is trying to avoid the vehicle ahead by steering avoidance control (either the left or right direction, hereinafter, also referred to as the "planned avoidance direction"). In this situation, there is a high possibility that the vehicle ahead will move in a direction away from the vehicle ahead after the vehicle ahead starts traveling along the avoidance path (i.e., after the steering avoidance control is started). If the steering avoidance control is started early and the vehicle ahead moves in the indicated direction after that, the amount of lateral movement of the vehicle ahead by the steering avoidance control may become excessive, or there may be a case where steering avoidance control is not actually required. As a result, the driver may find the steering avoidance control annoying.

[0005] On the other hand, in a situation where the indicated direction of the vehicle ahead is the same as the planned avoidance direction of the vehicle itself, the vehicle ahead may approach the steering avoidance path. In this case, there is a risk that the vehicle itself and the vehicle ahead may come too close or collide with each other, despite the vehicle itself trying to avoid a collision with the vehicle ahead by steering avoidance control.

[0006] The present disclosure has been made to address the above-mentioned problems. That is, one of the objectives of the present disclosure is to provide a vehicle control device that can prevent the host vehicle from coming too close to the vehicle ahead when executing collision avoidance control (steering avoidance control) and can reduce the possibility that the driver will feel bothered by the collision avoidance control. Hereinafter, the vehicle control device according to the present disclosure may be referred to as the "disclosed assistance device."

[0007] The present disclosure support device (10) The vehicle steering system includes a surroundings sensor (21) including a camera sensor (21b) for photographing an area ahead of a host vehicle (SV) and acquiring image data representing the area, and for acquiring information about a forward vehicle (OV1) that is another vehicle present in the area ahead of the host vehicle based on at least the image data; a steering angle actuator (52) configured to be able to change the steering angle of the host vehicle; and a control unit (20) for, when it is determined based on information from the surroundings sensor that a collision possibility condition that is established when there is a possibility that the host vehicle will collide with the forward vehicle is established (steps 710, 715, and 720), acquiring a target trajectory for the host vehicle to avoid collision with the forward vehicle by calculation using the image data (step 815), and when it is determined that a predetermined steering avoidance control start condition is established (step 850), starting steering avoidance control to control the steering angle actuator so that the host vehicle travels along the target trajectory (step 855).

[0008] Furthermore, the control unit The method obtains information on a planned avoidance direction indicating whether the target trajectory causes the host vehicle to change course to the left or right (step 830), determines whether the state of the turn indicator of the forward vehicle is a direction indicating state indicating the planned movement direction of the forward vehicle based on the image data (step 835), and if it is determined that the state of the turn indicator is the direction indicating state, obtains information on an indication direction indicating whether the planned movement direction of the forward vehicle indicated by the turn indicator is the left or right based on the image data (step 860), and if it is determined that the state of the turn indicator is not the direction indicating state, sets the steering avoidance control start condition to a first start condition that can be satisfied when the inter-vehicle distance between the host vehicle and the forward vehicle becomes a first distance. The steering avoidance control start condition is set to a condition (steps 840, 845), and if it is determined that the state of the direction indicator is the direction indicating state, it is determined whether or not the planned movement direction of the forward vehicle and the planned avoidance direction are the same based on information on the indicated direction and the planned avoidance direction information (step 865). When it is determined that the planned movement direction of the forward vehicle and the planned avoidance direction are the same, execution of the steering avoidance control is prohibited (step 865: No, step 825). When it is determined that the planned movement direction of the forward vehicle and the planned avoidance direction are different, the steering avoidance control start condition is set to a second start condition that can be satisfied when the inter-vehicle distance becomes shorter than the inter-vehicle distance at the time when the first start condition can be satisfied (steps 865: Yes, steps 870, 875).

[0009] According to the disclosed support device, it is determined whether the state of the turn signal of the forward vehicle is "a direction indicating state indicating that the forward vehicle is scheduled to move in either the left direction or the right direction." Furthermore, according to the disclosed support device, if it is determined that the state of the turn signal of the forward vehicle is a direction indicating state and the forward vehicle's scheduled movement direction and the scheduled avoidance direction are the same, the execution of steering avoidance control is prohibited. This allows the disclosed support device to reduce the possibility of the vehicle colliding with the forward vehicle.

[0010] Furthermore, according to the present disclosure support device, when it is determined that the state of the turn signal is not a direction indicating state, the steering avoidance control start condition is set to a first start condition that can be satisfied when the inter-vehicle distance between the vehicle and the vehicle ahead becomes a first distance. In contrast, when it is determined that the state of the turn signal of the vehicle ahead is a direction indicating state and the planned movement direction of the vehicle ahead differs from the planned avoidance direction, the steering avoidance control start condition is set to a second start condition. This second start condition is a condition that can be satisfied when the inter-vehicle distance between the vehicle and the vehicle ahead becomes shorter than the inter-vehicle distance at the time when the first start condition is satisfied. In other words, the second start condition is a condition that is satisfied at a later timing than the timing when the first start condition is satisfied. Therefore, when the planned movement direction of the vehicle ahead differs from the planned avoidance direction, the present disclosure support device can reduce the possibility that the amount of lateral movement of the vehicle ahead due to the steering avoidance control will be excessive, and as a result, the possibility that the driver will feel bothered by the steering avoidance control can be reduced.

[0011] In one aspect of the present disclosure support device, The steering avoidance control start condition includes at least a condition that a collision index value (TTC) indicating a possibility that the host vehicle will collide with the forward vehicle has reached a collision likelihood threshold value (TTCth), and the control unit sets the collision likelihood threshold value (TTC2) used in the second start condition to a value different from the collision likelihood threshold value (TTC1) used in the first start condition.

[0012] More specifically, the steering avoidance control start condition includes at least a condition that a collision prediction time (TTC), which is a predicted value of the time until the host vehicle collides with the vehicle in front, is shorter than a predetermined collision judgment threshold time (TTCth), and the control unit sets the collision judgment threshold time (TTCth) used in the first start condition to a first time (TTC1), and sets the collision judgment threshold time (TTCth) used in the second start condition to a second time (TTC2) shorter than the first time.

[0013] According to the above aspect, the collision determination threshold when the state of the turn signal of the forward vehicle is a turn indicating state and it is determined that the planned movement direction of the forward vehicle differs from the planned avoidance direction is set to a value different from the collision determination threshold when the state of the turn signal of the forward vehicle is not a turn indicating state. This makes it possible to set the steering avoidance control start condition when it is determined that the planned movement direction of the forward vehicle differs from the planned avoidance direction to a second start condition that can be met when the inter-vehicle distance becomes shorter than the inter-vehicle distance at the time when the first start condition can be met.

[0014] In the above description, in order to facilitate understanding of the present invention, the names and / or symbols used in the embodiments described below are enclosed in parentheses with respect to the configuration of the invention corresponding to the embodiments. However, each component of the present invention is not limited to the embodiments defined by the names and / or symbols. [Brief description of the drawings]

[0015] [Figure 1] FIG. 1 is a schematic diagram of a collision avoidance assistance device according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a diagram for explaining an overview of steering avoidance control. [Diagram 3] FIG. 3 is a diagram for explaining the first map Map1. [Figure 4] FIG. 4 is a diagram for explaining an outline of the operation of the collision avoidance assistance device. [Diagram 5] FIG. 5 is a diagram for explaining an outline of the operation of the collision avoidance assistance device. [Figure 6] FIG. 6 is a diagram for explaining the second map Map2. [Figure 7] FIG. 7 is a flowchart showing a routine executed by the CPU of the driving assistance ECU. [Figure 8] FIG. 8 is a flowchart showing a routine executed by the CPU of the driving assistance ECU. [Figure 9] FIG. 9 is a flowchart showing a routine executed by the CPU of the driving assistance ECU. [Figure 10] FIG. 10 is a diagram for explaining an outline of the operation of the modified collision avoidance assistance device. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] <Configuration> As shown in Fig. 1, a collision avoidance support device 10 according to an embodiment of the present invention is applied to a vehicle SV. The vehicle SV may be referred to as a host vehicle SV to distinguish it from other vehicles. The collision avoidance support device 10 includes a driving support ECU 20, an engine ECU 30, a brake ECU 40, and an electric power steering ECU 50. Hereinafter, the driving support ECU 20 will be referred to as a "DSECU," and the electric power steering ECU 50 will be referred to as an "EPS·ECU 50."

[0017] These ECUs are control units (Electronic / Electric Control Units) that include a microcomputer as a main component, and are also called controllers. These ECUs are connected to each other via a Controller Area Network (CAN70) to enable data exchange (communication). The microcomputer includes a CPU, ROM, RAM, and an interface (I / F), etc. The CPU realizes various functions by executing instructions (programs, routines) stored in the ROM. Some or all of these ECUs may be integrated into a single ECU.

[0018] The DSECU is connected to an ambient sensor 21, a vehicle speed sensor 22, a yaw rate sensor 23, a longitudinal acceleration sensor 24, and a lateral acceleration sensor 25. The DSECU receives detection signals or output signals of these sensors. Some or all of these sensors may be connected to an ECU other than the DSECU. In that case, the DSECU receives detection signals or output signals of these sensors from the other ECU via the CAN.

[0019] The surrounding sensor 21 includes a radar sensor 21a, a camera sensor 21b, and a target recognition unit 21c. The surrounding sensor 21 constitutes an "obstacle recognition device" from the viewpoint of function. The camera sensor 21b constitutes an "instruction direction acquisition device" from the viewpoint of function. The target recognition unit 21c includes an ECU including a microcomputer.

[0020] The surrounding sensor 21 recognizes three-dimensional objects present in the "peripheral area of ​​the host vehicle SV" including at least the "predetermined area (forward area) in front of the host vehicle SV" and acquires information about the recognized three-dimensional objects. The three-dimensional objects are moving objects (e.g., pedestrians and vehicles) or fixed objects (e.g., utility poles, trees, guardrails, etc.). Hereinafter, the three-dimensional objects may be referred to as "targets."

[0021] The surrounding sensor 21 acquires information about the recognized target (hereinafter, may be referred to as "target information") through calculation and transmits it to the DSECU. The target information includes the following information: · Longitudinal distance Dfx of the target: The longitudinal distance Dfx of the target is a signed distance in the central axis direction (x-axis direction) extending in the fore-and-aft direction of the host vehicle SV between the front end of the host vehicle SV and the target. · Lateral position Dfy of the target: The lateral position Dfy of the target is the signed distance between the center position of the target and the central axis of the host vehicle SV in the vehicle width direction, in the direction perpendicular to the central axis extending in the fore-and-aft direction of the host vehicle SV (y-axis direction). · Relative speed Vfx of the target: The relative speed Vfx of the target is the difference (= Vb - Vs) between the speed Vb of the target in the x-axis direction and the vehicle speed (speed in the x-axis direction) Vs of the host vehicle SV. Information indicating the type of target (e.g., whether the target is a vehicle, a pedestrian, or a stationary object) Target width (left and right width of target) W Target length L The longitudinal distance Dfx and the lateral position Dfy are also referred to as the "detected position of the target."

[0022] The surrounding sensor 21 acquires target information based on predefined xy coordinates. The x-axis is a coordinate axis that extends along the longitudinal direction of the host vehicle SV so as to pass through the center position in the vehicle width direction of the front end of the host vehicle SV, and has a positive value toward the front. The y-axis is a coordinate axis that is perpendicular to the x-axis and has a positive value toward the left of the host vehicle SV. The origin of the x-axis and the origin of the y-axis are a predetermined position of the host vehicle SV (for example, the center position in the vehicle width direction of the front end of the host vehicle SV).

[0023] More specifically, the radar sensor 21a includes a radar wave transmitting / receiving unit and a processing unit. The radar wave transmitting / receiving unit, for example, emits millimeter wave band radio waves (hereinafter referred to as "millimeter waves") to a peripheral area of ​​the vehicle SV including at least a forward area of ​​the vehicle SV, and receives reflected waves generated when the emitted millimeter waves are reflected by a portion of a three-dimensional object (i.e., a reflection point). Note that the radar sensor 21a may be a radar sensor that uses radio waves (radar waves) in a frequency band other than the millimeter wave band.

[0024] The processing unit of the radar sensor 21a determines the presence or absence of a target based on reflection point information including a phase difference between the transmitted millimeter wave and the received reflected wave, an attenuation level of the reflected wave, and a time from transmitting the millimeter wave to receiving the reflected wave. The processing unit of the radar sensor 21a groups "multiple reflection points" that are likely to detect one three-dimensional object, and recognizes the group of grouped reflection points as one target (see, for example, JP 2019-003235 A, JP 2019-002691 A, JP 2019-002690 A, etc.).

[0025] Furthermore, the processing unit of the radar sensor 21a calculates the longitudinal distance Dfx of the target, the lateral position Dfy of the target, the azimuth θp of the target with respect to the host vehicle SV, and the relative speed Vfx between the host vehicle SV and the target, based on the reflection point information of the reflection points belonging to the recognized target. Hereinafter, information including these values ​​acquired by the radar sensor 21a may be referred to as "radar sensor detection information."

[0026] The camera sensor 21b includes a stereo camera and an image processor. The stereo camera captures the scenery of the "left and right areas" ahead of the host vehicle SV (i.e., the area ahead of the host vehicle SV) to obtain a pair of left and right images (i.e., image data representing the area ahead). The image processor determines whether or not a target exists in the area ahead of the host vehicle SV based on the image data.

[0027] When the image processing unit determines that a target exists in the area ahead of the vehicle SV, the image processing unit acquires the target's azimuth θp, the target's longitudinal distance Dfx, and the relative speed Vfx between the vehicle SV and the target, etc., by calculation based on the image data. Furthermore, the image processing unit identifies the type of the target by pattern matching based on the image data, and acquires information indicating the type of the target. The information acquired by the image processing unit is sometimes referred to as "camera sensor detection information."

[0028] The target recognition unit 21c receives "radar sensor detection information" and "camera sensor detection information" from the processing unit of the radar sensor 21a and the image processing unit of the camera sensor 21b, respectively.

[0029] The target recognition unit 21c determines (acquires) the final target information of the above-mentioned target based on the "radar sensor detection information" and the "camera sensor detection information". The target recognition unit 21c transmits the determined final target information of the target to the DSECU every time a predetermined time elapses.

[0030] The image processing unit of the camera sensor 21b recognizes the left and right lane markings (hereinafter also simply referred to as "white lines") of the road by a well-known method based on the acquired image data. For example, the image processing unit detects edge points where the brightness of the image changes suddenly, and extracts the contours of the white lines based on the detected edge points, thereby recognizing the left and right white lines.

[0031] Then, the image processing unit calculates and obtains position information (x coordinate position and y coordinate position on the above-mentioned xy coordinate system) of the left and right white lines that define the lane (driving lane) in which the vehicle SV is traveling every time a predetermined time has elapsed, and transmits the information to the DSECU.

[0032] Furthermore, when the surrounding sensor 21 (image processing unit of the camera sensor 21b) recognizes that the type of target located in front of the host vehicle SV is a vehicle (hereinafter also referred to as a "forward vehicle"), it acquires the turn signal information described below based on current and past image data and transmits the acquired turn signal information to the DSECU. Information about whether the direction indicators of the vehicle ahead are flashing (operating). -If the direction indicator of the vehicle ahead is flashing, information as to whether only one of the "left direction indicator and right direction indicator" of the vehicle ahead is flashing. If only one of the "left turn indicator and right turn indicator" of the vehicle ahead is flashing, information indicating which of the left turn indicator and right turn indicator is flashing (hereinafter, this may be referred to as "information about the indicated direction, or indicated direction information").

[0033] Specifically, when only the left turn indicator of the left and right turn indicators is flashing, the image processing unit acquires "information indicating that the indicated direction is left" as the information on the indicated direction. When only the right turn indicator of the left and right turn indicators is flashing, the image processing unit acquires "information indicating that the indicated direction is right" as the information on the indicated direction. Note that when neither the left nor the right turn indicator is flashing, and when both the left and the right turn indicators are flashing, the indicated direction is not specified. Therefore, in these cases, the image processing unit transmits "information indicating that the state of the turn indicator is not in a direction indicating state (i.e., the indicated direction cannot be specified)" as the information on the indicated direction to the DSECU.

[0034] The vehicle speed sensor 22 detects the traveling speed (vehicle speed) of the host vehicle SV, and outputs a signal indicative of the detected vehicle speed Vs.

[0035] The yaw rate sensor 23 detects the yaw rate of the host vehicle SV, and outputs a signal indicative of the yaw rate Yr.

[0036] The longitudinal acceleration sensor 24 detects the longitudinal acceleration of the host vehicle SV and outputs a signal representative of the detected longitudinal acceleration Gx. When the longitudinal acceleration Gx has a negative value, the magnitude (absolute value) of the longitudinal acceleration Gx represents the deceleration.

[0037] The lateral acceleration sensor 25 detects the lateral acceleration of the host vehicle SV, and outputs a signal representative of the detected lateral acceleration Gy.

[0038] The engine ECU 30 is connected to an engine actuator 31. The engine actuator 31 includes a throttle valve actuator that changes the opening degree of a throttle valve of the engine 32. The engine ECU 30 can change the torque generated by the engine 32 by driving the engine actuator 31. The torque generated by the engine 32 is transmitted to drive wheels via a transmission (not shown).

[0039] Therefore, the engine ECU 30 can control the driving force of the host vehicle SV and change the acceleration state (longitudinal acceleration Gx) of the host vehicle SV by controlling the engine actuator 31. If the host vehicle SV is a hybrid vehicle, the engine ECU 30 can control the driving force of the host vehicle SV generated by either or both of the "engine and electric motor" as the vehicle driving source. Furthermore, if the host vehicle SV is an electric vehicle, the engine ECU 30 can control the driving force of the host vehicle SV generated by the electric motor as the vehicle driving source.

[0040] The brake ECU 40 is connected to a brake actuator 41. The brake actuator 41 is provided in a hydraulic circuit between a master cylinder (not shown) that pressurizes hydraulic oil in response to the depression force of the brake pedal, and friction brake mechanisms 42 provided on each of the left, right, front and rear wheels. The friction brake mechanism 42 includes a brake disc 42a fixed to the wheel and a brake caliper 42b fixed to the vehicle body.

[0041] The brake actuator 41 adjusts the hydraulic pressure supplied to the wheel cylinder built into the brake caliper 42b in response to an instruction from the brake ECU 40, and activates the wheel cylinder with the hydraulic pressure. As a result, the brake actuator 41 presses the brake pad against the brake disc 42a to generate a friction braking force. Therefore, the brake ECU 40 can control the braking force of the host vehicle SV by controlling the brake actuator 41, thereby changing the acceleration state (negative longitudinal acceleration Gx) of the host vehicle SV.

[0042] EPS·ECU 50 is a controller for a well-known electric power steering system. EPS·ECU 50 is connected to a motor driver 51. Motor driver 51 is connected to a steering motor 52. Steering motor 52 is incorporated in a "steering mechanism including a steering wheel SW, a steering shaft SF, and a steering gear mechanism (not shown)". Steering motor 52 is an electric motor, and generates steering torque by electric power supplied from motor driver 51. Steering motor 52 can steer the left and right steered wheels of vehicle SV by this steering torque. That is, steering motor 52 functions as a steering angle actuator that changes the steering angle of vehicle SV (the steered angle of the steered wheels).

[0043] The EPS·ECU 50 is connected to a steering angle sensor 53 and a steering torque sensor 54. The steering angle sensor 53 detects the steering angle of the steering wheel SW of the host vehicle SV, and outputs a signal representing the steering angle θs. The steering torque sensor 54 detects the steering torque (hereinafter referred to as "driver torque TqDr") applied to the steering shaft SF of the host vehicle SV by operation of the steering wheel SW, and outputs a signal representing the driver torque TqDr. The steering angle θs and the driver torque TqDr are defined to be positive values ​​when the host vehicle SV is steered in a left turning direction, and negative values ​​when the host vehicle SV is steered in a right turning direction.

[0044] The EPS·ECU 50 drives the steering motor 52 based on the detected "driver torque TqDr, steering angle θs, and vehicle speed Vs." As a result, the EPS·ECU 50 generates a steering assist torque to assist the driver's steering operation.

[0045] When EPS·ECU 50 receives a steering command from the DSECU while executing steering avoidance control described below, it drives steering motor 52 via motor driver 51 based on the target steering angle (or target steering torque) specified by the steering command. This enables the DSECU to automatically change the steering angle of the host vehicle SV (steer the steered wheels) via EPS·ECU 50.

[0046] <Outline of basic steering avoidance control> As shown in FIG. 2, it is assumed that a situation occurs in which a leading vehicle OV1, which is a three-dimensional object (target), is present in the area ahead of the host vehicle SV while the host vehicle SV is traveling on a driving lane LA1, which is a straight road.

[0047] The DSECU recognizes the driving lane LA1 defined by the left white line WL and the right white line WR every time a predetermined time period elapses, based on the position information of the left white line WL and the right white line WR.

[0048] Furthermore, the DSECU assumes that the host vehicle SV will maintain its current driving state, and calculates a predicted driving trajectory of the host vehicle SV based on the steering angle θs, yaw rate Yr, and vehicle speed Vs of the host vehicle SV.

[0049] The DSECU calculates a predicted movement trajectory of the forward vehicle OV1 based on the target information of the forward vehicle OV1, assuming that the forward vehicle OV1 will maintain the current traveling state. More specifically, the DSECU obtains a predicted movement trajectory along which the forward vehicle OV1 is predicted to move, based on a plurality of detection positions of the forward vehicle OV1 obtained at predetermined time intervals in the past and the detection position of the forward vehicle OV1 at the current point.

[0050] The DSECU determines whether a collision possibility condition is satisfied based on the predicted travel trajectory of the host vehicle SV and the predicted movement trajectory of the forward vehicle OV1. The collision possibility condition is satisfied when there is a possibility that the host vehicle SV will collide with the forward vehicle OV1 (the two predicted travel trajectories intersect) if the forward vehicle OV1 maintains its current movement state and the host vehicle SV maintains its current traveling state. If the DSECU determines that the collision possibility condition is satisfied, it determines that there is a possibility that the host vehicle SV will collide with the forward vehicle OV1 (i.e., there is a forward vehicle OV1 that may collide with the host vehicle SV).

[0051] When the DSECU determines that there is a possibility that the host vehicle SV will collide with the forward vehicle OV1, the DSECU calculates a collision prediction time TTC for the forward vehicle OV1 based on the longitudinal distance Dfx and the relative speed Vfx of the forward vehicle OV1. Specifically, the DSECU calculates the collision prediction time TTC by inverting the sign of the value obtained by dividing the longitudinal distance Dfx by the relative speed Vfx (i.e., TTC=-Dfx / Vfx). The DSECU may calculate the collision prediction time TTC by dividing the distance between the host vehicle SV and a point where the host vehicle SV and the forward vehicle OV1 are expected to collide (a point where the above two predicted driving trajectories intersect) by the current vehicle speed Vs of the host vehicle SV.

[0052] Furthermore, the DSECU calculates a trajectory that the host vehicle SV can take to avoid a collision with the forward vehicle OV1 by a well-known method. More specifically, the DSECU sets a trajectory that can avoid interference (collision) with the forward vehicle OV1 by turning (changing the course direction) the host vehicle SV as a target trajectory a1 (for determining the avoidance target trajectory a1, see, for example, Japanese Patent Application Publication No. 2017-105383, Japanese Patent Application Publication No. 2017-43262, and Japanese Patent Application Publication No. 2018-106230, etc.). Hereinafter, such a target trajectory a1 may be referred to as an "avoidance target trajectory a1". In this example, the avoidance target trajectory a1 is determined based on target information about the forward vehicle OV1, the positions of the left and right white lines, etc., so that at least all of the following conditions (conditions A1 to A3) are satisfied. Condition A1: An avoidance space SP1 through which the host vehicle SV can pass exists on either the left or right side of the forward vehicle OV1, which is located at a point where a collision between the host vehicle SV and the forward vehicle OV1 is expected. Condition A2: The host vehicle SV does not deviate from the driving lane LA1 defined by the left and right white lines. Condition A3: If the host vehicle SV travels from the current traveling state along the avoidance target trajectory a1, it can pass through the avoidance space while maintaining the magnitude of the lateral acceleration Gy and the magnitude of the yaw rate Yr below their respective threshold values.

[0053] Then, the DSECU judges whether or not a predetermined steering avoidance control start condition is satisfied. The steering avoidance control start condition is satisfied when both a first condition and a second condition described below are satisfied. First condition: The first condition is met when the collision prediction time TTC is shorter than the threshold time TTCth. For convenience, the threshold time TTCth is also referred to as the "collision determination threshold time." The collision prediction time TTC is a value that indicates that the smaller its value is, the higher the possibility of a collision is, and can also be called a collision index value. Therefore, it can be said that the first condition is met when the possibility of a collision indicated by the collision index value is equal to or greater than the collision possibility threshold. Second condition: The second condition is met when, assuming that the host vehicle SV travels along the avoidance target trajectory a1, there is no "target other than the preceding vehicle OV1" that would collide with the host vehicle SV or whose distance to the host vehicle SV is less than a predetermined minimum distance.

[0054] When the steering avoidance control start condition is met, the DSECU calculates a target yaw rate for causing the host vehicle SV to travel along the avoidance target trajectory a1.

[0055] The DSECU calculates a target steering angle of the steering wheels of the host vehicle SV that will obtain the target yaw rate based on the calculated target yaw rate and the vehicle speed Vs of the host vehicle SV, and transmits a steering command for collision avoidance representing this target steering angle to the EPS·ECU 50.

[0056] The EPS·ECU 50 calculates a target steering torque required to make the actual steering angle coincide with the target steering angle. The EPS·ECU 50 drives the steering motor 52 to output a steering torque corresponding to the calculated target steering torque, thereby steering the wheels of the host vehicle SV. As described above, the DSECU changes the steering angle of the host vehicle SV via the EPS·ECU 50, thereby causing the host vehicle SV to travel along the avoidance target trajectory a1. In this case, the host vehicle SV does not deviate from the driving lane LA1, does not collide with other objects, and can avoid a collision with the preceding vehicle OV1. This is an overview of the basic steering avoidance control.

[0057] <Outline of steering avoidance control according to turn signal status> When the DSECU determines that there is a possibility that the host vehicle SV will collide with the forward vehicle OV1, the DSECU acquires from the surroundings sensor 21 the above-mentioned "turn signal information including the indicated direction information."

[0058] Furthermore, the DSECU acquires information about the planned avoidance direction of the host vehicle SV based on the avoidance target trajectory a1. For example, if the avoidance target trajectory a1 curves to the right (i.e., if the avoidance target trajectory a1 is a trajectory that moves the position of the host vehicle SV in the lane width direction to the right), the DSECU acquires information indicating that "the planned avoidance direction is a rightward direction" as information about the planned avoidance direction. Similarly, if the avoidance target trajectory a1 curves to the left (i.e., if the avoidance target trajectory a1 is a trajectory that moves the position of the host vehicle SV in the lane width direction to the left), the DSECU acquires information indicating that "the planned avoidance direction is a leftward direction" as information about the planned avoidance direction.

[0059] (When the turn signal is not in the turn signal state) When the state of the turn signal is not the turn signal state described above, the DSECU sets the threshold time TTCth used in the first condition of the steering avoidance control start condition to the first time TTC1. For convenience, the steering avoidance control start condition in which the threshold time TTCth used in the first condition is set to the first time TTC1 is also referred to as the "first start condition." Setting the threshold time TTCth to the first time TTC1 can be said to be synonymous with setting the collision possibility threshold to the first possibility threshold.

[0060] More specifically, the DSECU determines the first time TTC1 by applying the absolute value (|Vfx|) of the relative speed Vfx of the forward vehicle OV1 to a first map Map1 which is a look-up table shown in Fig. 3. According to the first map Map1, as shown by the dotted line Ln1, the first time TTC1 is set to be longer as the absolute value of the relative speed Vfx of the forward vehicle OV1 increases.

[0061] (When the direction indicated by the turn signal of the forward vehicle OV1 is the same as the planned avoidance direction of the host vehicle SV) 4, the right turn signal of the forward vehicle OV1 is activated (i.e., the turn signal is pointing to the right), and the planned avoidance direction of the host vehicle SV is to the right. Therefore, the direction indicated by the turn signal is the same as the planned avoidance direction of the host vehicle SV.

[0062] In this way, when the direction indicated by the turn signal of the forward vehicle OV1 is the same as the planned avoidance direction of the host vehicle SV, there is a possibility that the forward vehicle OV1 will start moving in the indicated direction after the steering avoidance control is started. If the forward vehicle OV1 starts moving in the indicated direction after the steering avoidance control is started, there is a risk that the host vehicle SV and the forward vehicle OV1 will collide despite the host vehicle SV trying to avoid a collision with the forward vehicle OV1 by the steering avoidance control. Therefore, in this case, the DSECU prohibits the execution of the steering avoidance control. This allows the DSECU to reduce the possibility that the host vehicle SV will collide with the forward vehicle OV1 despite the execution of the steering avoidance control. Note that the DSECU is also capable of executing collision avoidance control by the well-known automatic braking control. Therefore, in this case, a collision between the host vehicle SV and the forward vehicle OV1 is avoided by the automatic braking control.

[0063] (When the indicated direction of the preceding vehicle OV1 differs from the planned avoidance direction of the host vehicle SV) In the example shown in FIG. 5, the left turn signal of the forward vehicle OV1 is operating (i.e., the direction indicated by the turn signal is the left direction), and the planned avoidance direction of the host vehicle SV is the right direction. Therefore, the direction indicated by the turn signal is different from the planned avoidance direction of the host vehicle SV (they are opposite to each other). If the direction indicated by the turn signal of the forward vehicle OV1 is different from the planned avoidance direction of the host vehicle SV, there is a high possibility that the forward vehicle OV1 will move in a direction away from the host vehicle SV after the host vehicle SV starts traveling along the avoidance path (i.e., after the steering avoidance control is started). Therefore, if the steering avoidance control is started early and the forward vehicle OV1 then moves in the indicated direction, the amount of lateral movement of the host vehicle SV due to the steering avoidance control will be excessive. As a result, the driver may find the steering avoidance control annoying. In other words, even if the preceding vehicle OV1 is expected to move in a direction away from the host vehicle SV and the driver judges that steering to avoid the obstacle is not necessary or that slight steering is sufficient, the steering to avoid the obstacle may be performed without taking into consideration the movement of the preceding vehicle OV1. As a result, the driver may find the steering to avoid the obstacle annoying.

[0064] Therefore, in this case, when the first condition (TTC < TTCth) is satisfied, the DSECU sets the first condition such that the inter-vehicle distance between the host vehicle SV and the preceding vehicle OV1 at that time is shorter than the inter-vehicle distance at the time when the first condition is satisfied when the state of the turn signal is not the turn signal state. Specifically speaking, in this case, the DSECU sets the threshold time TTCth of the first condition to a second time TTC2 that is shorter than the first time TTC1. Note that the steering avoidance control start condition in which the threshold time TTCth used in the first condition is set to the second time TTC2 is also referred to as the "second start condition" for convenience. It can be said that setting the threshold time TTCth to the second time TTC2 is synonymous with setting the collision possibility threshold to a "second possibility threshold that is larger than the first possibility threshold".

[0065] More specifically speaking, the DSECU determines the second time TTC2 by applying the absolute value (|Vfx|) of the relative speed Vfx of the preceding vehicle OV1 to a second map Map2, which is a look-up table shown in FIG. 6. According to the second map Map2, as shown by the solid line Ln2, the second time TTC2 is set such that it becomes longer as the absolute value of the relative speed Vfx of the preceding vehicle OV1 increases. Furthermore, according to the second map Map2, the second time TTC2 is set to be shorter than the first time TTC1 shown by the dotted line Ln1 for any absolute value (|Vfx|) of the relative speed Vfx of the preceding vehicle OV1.

[0066] Therefore, when the relative speed Vfx of the preceding vehicle OV1 is a certain value (any value), the timing at which the steering avoidance control start condition is satisfied when the threshold time TTCth is set to the second time TTC2 is later than the timing at which the steering avoidance control start condition is satisfied when the threshold time TTCth is set to the first time TTC1. In other words, the second start condition is a condition that can be satisfied when the inter-vehicle distance between the host vehicle SV and the preceding vehicle OV1 becomes shorter than the inter-vehicle distance between the host vehicle SV and the preceding vehicle OV1 at the time when the first start condition is satisfied. Thereby, the DSECU can reduce the possibility that the driver feels bothered by the steering avoidance control.

[0067] <Specific operation> The CPU of the DSECU (hereinafter simply referred to as the "CPU") executes each of the routines shown in the flowcharts of FIGS. 7 to 9 every time a predetermined time has elapsed.

[0068] Therefore, at a predetermined timing, the CPU starts the process from step 700 in FIG. 7 and proceeds to step 705 to determine whether the value of the flag (collision possibility flag) Xf is "0" or not. When the value of the flag Xf is "0", it indicates that there is no preceding vehicle OV1 that may collide with the host vehicle SV. When the value of the flag Xf is "1", it indicates that there is a preceding vehicle OV1 that may collide with the host vehicle SV. The value of the flag Xf is set to "0" in an initialization routine executed by the CPU when the ignition key switch (not shown) of the host vehicle SV is changed from the OFF position to the ON position.

[0069] If the value of flag Xf is "0", the CPU determines "Yes" in step 705 and proceeds to step 710, where it determines whether or not a forward vehicle OV1 is present in a predetermined area ahead of the host vehicle SV, based on the target information acquired from the surrounding sensor 21. For example, the forward area is a range within a predetermined distance from the host vehicle SV in the traveling direction of the host vehicle SV, and has a width in the vehicle width direction of the host vehicle SV that is a predetermined distance wider than the vehicle width of the host vehicle SV.

[0070] If the preceding vehicle OV1 is not present in the area ahead of the host vehicle SV, the CPU makes a "No" determination in step 710, proceeds to step 795, and temporarily ends this routine.

[0071] If the preceding vehicle OV1 is present in the area ahead of the host vehicle SV, the CPU judges "Yes" in step 710 and proceeds to step 715, where it judges whether or not there is a possibility that the host vehicle SV will collide with the preceding vehicle OV1 by the above-mentioned method. That is, the CPU judges whether or not the above-mentioned collision possibility condition is satisfied.

[0072] If there is no possibility that the host vehicle SV will collide with the forward vehicle OV1, the CPU makes a "No" determination in step 715, proceeds to step 795, and temporarily ends this routine.

[0073] On the other hand, if there is a possibility that the host vehicle SV will collide with the forward vehicle OV1, the CPU determines "Yes" in step 715 and proceeds to step 720, where it sets the value of the flag Xf to "1." After that, the CPU proceeds to step 795 and temporarily ends this routine.

[0074] If the value of flag Xf is "1" at the time when the CPU executes the process of step 705, the CPU determines "No" in step 705 and proceeds to step 795, where it temporarily ends this routine.

[0075] At a prescribed timing, the CPU starts processing from step 800 in Fig. 8 and proceeds to step 805, where it judges whether or not steering avoidance control is not being executed (whether or not steering avoidance control is not being executed). More specifically, the CPU judges that steering avoidance control is being executed when the current time is within a control execution period from when steering avoidance control is started to when steering avoidance control is ended (or stopped) (see step 910 in Fig. 9 described later). The CPU judges that steering avoidance control is not being executed when the current time is within a period other than the control execution period. When the current time is within the control execution period, i.e., when steering avoidance control is being executed, the CPU judges "No" at step 805, proceeds to step 895, and temporarily ends this routine.

[0076] On the other hand, if steering avoidance control is not being executed, the CPU judges "Yes" in step 805 and proceeds to step 810, where it determines whether the value of flag Xf is "1" or not.

[0077] If the value of flag Xf is "0", the CPU makes a "No" determination in step 810 and proceeds to step 895 to temporarily end this routine.

[0078] On the other hand, if the value of flag Xf is "1", the CPU determines "Yes" in step 810 and proceeds to step 815, where it calculates an avoidance target trajectory a1 for the forward vehicle OV1 with which it was determined in step 715 that there is a possibility of collision with the host vehicle SV. After that, the CPU proceeds to step 820, where it determines whether or not the avoidance target trajectory a1 exists (i.e., whether or not a trajectory that satisfies all of the above-mentioned conditions A1 to A3 exists).

[0079] If the avoidance target trajectory a1 does not exist, the CPU judges "No" in step 820 and proceeds to step 825, where it sets the value of the flag Xf to "0", and then proceeds to step 895 and ends this routine. Therefore, in this case, steering avoidance control is not performed for the forward vehicle OV1 (steering avoidance control is prohibited). However, in this case, automatic braking avoidance control is generally executed.

[0080] On the other hand, if the avoidance target trajectory a1 exists, the CPU judges "Yes" in step 820 and proceeds to step 830, where it acquires the planned avoidance direction of the host vehicle SV based on the information on the planned avoidance direction. After that, the CPU proceeds to step 835, where it judges whether the state of the turn indicator is the above-mentioned direction indication state (whether the indicated direction of the turn indicator of the forward vehicle OV1 has been acquired) based on the information on the indicated direction.

[0081] If the state of the direction indicator is not the direction indicating state described above, the CPU judges “No” in step 835 and executes the processes of steps 840 and 845 described below in order, and then proceeds to step 850 .

[0082] Step 840: The CPU obtains the first time TTC1 by applying the absolute value (|Vfx|) of the relative speed Vfx of the forward vehicle OV1 to the first map Map1. Step 845: The CPU sets the threshold time TTCth to the first time TTC1.

[0083] After that, the CPU proceeds to step 850 and determines whether or not the above-mentioned steering avoidance control start conditions (i.e., both the first condition and the second condition) are satisfied. In this case, the threshold time TTCth of the first condition is set to the first time TTC1.

[0084] If the steering avoidance control start condition is not satisfied, the CPU judges "No" in step 850, proceeds to step 895, and temporarily ends this routine.

[0085] If the steering avoidance control start condition is satisfied, the CPU judges "Yes" in step 850 and proceeds to step 855 to start the execution of steering avoidance control. That is, the CPU starts to make the host vehicle SV travel along the avoidance target trajectory a1. After that, the CPU proceeds to step 895 to temporarily end this routine.

[0086] When the CPU executes the process of step 835, if the state of the turn indicator is the above-mentioned turn indication state, the CPU determines "Yes" in step 835 and proceeds to step 860. The CPU acquires the indication direction based on the information about the indication direction in step 860. Next, the CPU proceeds to step 865 and determines whether or not the indication direction of the turn indicator differs from the planned avoidance direction.

[0087] If the direction indicated by the direction indicator is the same as the planned avoidance direction, the CPU judges "No" in step 865 and proceeds to step 825, sets the value of flag Xf to "0", and then proceeds to step 895 to end this routine. Therefore, in this case, steering avoidance control is not performed for the forward vehicle OV1 (steering avoidance control is prohibited).

[0088] If the direction indicated by the direction indicator differs from the planned avoidance direction, the CPU judges "Yes" in step 865 and executes the processes of "step 870 and step 875" described below in order, and then proceeds to step 850.

[0089] Step 870: The CPU obtains the second time TTC2 by applying the absolute value (|Vfx|) of the relative speed Vfx of the forward vehicle OV1 to the second map Map2. Step 875: The CPU sets the threshold time TTCth to the second time TTC2. As described above, the second time TTC2 for any absolute value (|Vfx|) is shorter than the first time TTC1 for the arbitrary absolute value (|Vfx|).

[0090] When the CPU proceeds to step 850, it determines whether or not the above-mentioned steering avoidance control start conditions (i.e., both the first condition and the second condition) are satisfied. In this case, the second time TTC2 is set as the threshold time TTCth of the first condition.

[0091] If the steering avoidance control start condition is not satisfied, the CPU judges "No" in step 850, proceeds to step 895, and temporarily ends this routine.

[0092] On the other hand, if the steering avoidance control start condition is satisfied, the CPU judges "Yes" in step 850 and proceeds to step 855 to start the execution of the steering avoidance control. In this case, the steering avoidance control is started at a later timing than when the threshold time TTCth of the steering avoidance control start condition is set to the first time TTC1. In other words, since the threshold time TTCth of the steering avoidance control start condition is set to the second time TTC2, the steering avoidance control is started at a point in time when the inter-vehicle distance between the host vehicle SV and the forward vehicle OV1 at the time when the steering avoidance control is started becomes smaller than when the threshold time TTCth of the steering avoidance control start condition is set to the first time TTC1. After that, the CPU proceeds to step 895 and temporarily ends this routine.

[0093] At a predetermined timing, the CPU starts the process from step 900 in FIG. 9, proceeds to step 905, and determines whether steering avoidance control is being executed.

[0094] If steering avoidance control is not being executed, the CPU judges "No" in step 905 and proceeds to step 995, where it temporarily ends this routine.

[0095] If the steering avoidance control is being executed, the CPU judges "Yes" in step 905 and proceeds to step 910 to judge whether or not a predetermined condition for ending the steering avoidance control is satisfied. For example, the condition for ending the steering avoidance control is satisfied when the host vehicle SV travels along the avoidance target trajectory a1 and is aligned with the forward vehicle OV1 in the lane width direction.

[0096] If the condition for terminating the steering avoidance control is not satisfied, the CPU judges "No" in step 910, proceeds to step 995, and temporarily terminates this routine.

[0097] If the termination condition for steering avoidance control is met, the CPU judges "Yes" in step 910, sequentially executes the processing of "step 915 and step 920" described below, and then proceeds to step 995 and temporarily terminates this routine.

[0098] Step 915: The CPU ends the steering avoidance control. Step 920: The CPU sets the value of flag Xf to “0”.

[0099] The present disclosure is not limited to the above-described embodiments, and various modified examples based on the technical ideas of the present disclosure may be adopted within the scope of the present disclosure.

[0100] For example, in the above-described embodiment, each of the first time TTC1 and the second time TTC2 may be changed according to the lap rate LR. The lap rate LR in this case is an index indicating the "degree of overlap in the vehicle width direction between the host vehicle SV and the preceding vehicle OV1" at the time when a collision between the host vehicle SV and the preceding vehicle OV1 is predicted. The lap rate LR is calculated by dividing the length by which the host vehicle SV overlaps the preceding vehicle OV1 in the vehicle width direction by the vehicle width of the host vehicle SV. In this case, the first time TTC1 is set to be longer as the lap rate LR increases. The second time TTC2 is set to be longer as the lap rate LR increases and shorter than the first time TTC1 corresponding to the same absolute value (|Vfx|) and the same lap rate LR.

[0101] In the above-described embodiment, at least a part of the processing performed by the target recognition unit 21c and / or the surrounding sensor 21 may be performed by the DSECU. Further, the collision index value is not limited to the collision prediction time TTC, and may be obtained, for example, by applying the relative relationship between the positions of the host vehicle SV and the preceding vehicle OV1, the motion state of the host vehicle SV, the motion state of the preceding vehicle OV1, etc. to a predetermined look-up table.

[0102] <Modification Example> Furthermore, as another modification example of the present disclosure, the following modification example may be adopted. In this modification example, the avoidance target trajectory and the limit index value (steering avoidance limit index value) TTS are obtained as described later, and the steering avoidance control is started when the limit index value TTS becomes "0". That is, the limit index value TTS is the time from the current point until the time when it is necessary to start the steering avoidance control. It can be said that the condition that the limit index value TTS is "0" is a condition that replaces the first condition (i.e., TTC < TTCth) of the above-described steering avoidance control start condition.

[0103] The operation of the modified example will be specifically described below with reference to Fig. 10. The vertical axis of the coordinate system in Fig. 10 represents the lateral (vehicle width) position of the host vehicle SV (hereinafter referred to as "lateral position"). The origin of this vertical axis is the center position of the front end of the host vehicle SV in the vehicle width direction. This vertical axis is defined so that the leftward direction of the host vehicle SV is the positive direction of the vertical axis. The horizontal axis of the coordinate system in Fig. 10 represents time from the current time (elapsed time).

[0104] First, the DSECU calculates the collision prediction time TTC as described above using the target information of the forward vehicle OV1. Next, the DSECU uses the target information of the forward vehicle OV1 to obtain a first position P1a at a time tc1 when the collision prediction time TTC has elapsed from the current time. The first position P1a is a position obtained by moving the lateral position P1 of the left rear end of the forward vehicle OV1 at the time tc1 by a predetermined first distance d1 (margin) in the positive direction along the vertical axis of FIG. Similarly, the DSECU obtains a second position P2a at the time tc1. The second position P2a is a position obtained by moving the lateral position P2 of the right rear end of the leading vehicle OV1 at the time tc1 by a predetermined second distance d2 (margin) in the negative direction along the vertical axis of FIG.

[0105] The DSECU calculates a target trajectory of the left front end LFr of the host vehicle SV based on a predetermined lateral acceleration profile (the relationship between the elapsed time from the start of the steering avoidance control and the lateral acceleration) of the host vehicle SV stored in the ROM. This lateral acceleration profile is, for example, a profile in which the lateral acceleration increases in proportion to time from "0" to "lateral acceleration of magnitude A" as time elapses from the start of the steering avoidance control, and then the lateral acceleration is maintained at "lateral acceleration of magnitude A". When calculating the target trajectory of the left front end LFr, the DSECU uses a value obtained by adding a negative sign to the "magnitude of the lateral acceleration defined by the lateral acceleration profile" as the lateral acceleration. The DSECU calculates a predicted collision avoidance trajectory LO1 of the left front end LFr of the host vehicle SV by moving the target trajectory so that the starting point (start point) of the target trajectory thus calculated is on the path LLFr along which the left front end LFr of the host vehicle SV is likely to pass, and the target trajectory passes through the second position P2a.

[0106] Next, the DSECU identifies the "point in time TS1 at which steering should be started (point in time required to start steering)" that is required for moving the left front end LFr of the host vehicle SV along the predicted collision avoidance trajectory LO1. Furthermore, the DSECU obtains the time from the current time to the point in time TS1 required to start steering as a first steering start margin time T1. The DSECU can also calculate the first steering start margin time T1 by dividing the distance from the current position of the host vehicle SV to the starting point PSL of the predicted collision avoidance trajectory LO1 by the current vehicle speed Vs of the host vehicle SV.

[0107] Similarly, the DSECU calculates a target trajectory of the right front end RFr of the host vehicle SV based on the above-mentioned lateral acceleration profile. When calculating the target trajectory of the right front end RFr, the DSECU uses a value obtained by adding a positive sign to the "magnitude of the lateral acceleration defined by the lateral acceleration profile" as the lateral acceleration. The DSECU calculates a predicted collision-avoidance trajectory RO1 of the right front end RFr of the host vehicle SV by moving the target trajectory calculated in this manner so that the starting point (starting point) of the target trajectory is on the path LRFr along which the right front end RFr of the host vehicle SV is likely to pass and the target trajectory passes through the first position P1a.

[0108] Next, the DSECU identifies a "point in time TS2 at which steering should be started (point in time required to start steering)" that is required for moving the right front end RFr of the host vehicle SV along the predicted collision avoidance trajectory RO1. Furthermore, the DSECU obtains the time from the current time to the point in time TS2 required to start steering as a second steering start margin time T2. The DSECU can also calculate the second steering start margin time T2 by dividing the distance from the current position of the host vehicle SV to the starting point PSR of the predicted collision avoidance trajectory RO1 by the current vehicle speed Vs of the host vehicle SV.

[0109] Next, an overview of the steering avoidance control executed by this modified example will be described. The modified DSECU determines whether the above-mentioned collision possibility condition is satisfied, and if it is determined that the collision possibility condition is satisfied (i.e., if it is determined that there is a forward vehicle OV1 that may collide with the host vehicle SV), it performs the following processing.

[0110] (1) The DSECU calculates the collision avoidance predicted trajectory LO1, the first steering initiation margin time T1, the collision avoidance predicted trajectory RO1, and the second steering initiation margin time T2 by the above-mentioned method.

[0111] (2) The DSECU determines whether or not a rightward steering avoidance condition is satisfied. The rightward steering avoidance condition is satisfied when both of the following conditions are satisfied: At the time when a collision between the host vehicle SV and the leading vehicle OV1 is predicted (the time tc1 when the collision prediction time TTC has elapsed from the current time), there is an avoidance space to the right of the leading vehicle OV1 through which the host vehicle SV can pass without deviating from the driving lane. When the host vehicle SV travels such that the left front end LFr of the host vehicle SV moves along the predicted collision avoidance trajectory LO1, there are no "objects other than the preceding vehicle OV1" that will collide with the host vehicle SV or whose distance to the host vehicle SV is less than a predetermined minimum distance.

[0112] (3) The DSECU determines whether or not a leftward steering avoidance condition is satisfied. The leftward steering avoidance condition is satisfied when the following two conditions are satisfied: At time tc1 when a collision between the host vehicle SV and the forward vehicle OV1 is predicted, there is an avoidance space to the left of the forward vehicle OV1 through which the host vehicle SV can pass without deviating from the driving lane. When the host vehicle SV travels such that the right front end RFr of the host vehicle SV moves along the predicted collision avoidance trajectory RO1, there are no "objects other than the preceding vehicle OV1" that will collide with the host vehicle SV or whose distance to the host vehicle SV is less than a predetermined minimum distance.

[0113] (4) When neither the rightward steering avoidance condition nor the leftward steering avoidance condition is satisfied, the DSECU prohibits steering avoidance control. At this time, the DSECU sets the limit index value TTS to a time that is substantially infinite.

[0114] (5) When the rightward steering avoidance condition is satisfied but the leftward steering avoidance condition is not satisfied, the DSECU adopts the predicted collision avoidance trajectory LO1 as the avoidance target trajectory for the left front end LFr of the host vehicle SV, and adopts the first steering start margin time T1 as the limit index value TTS.

[0115] (6) When the left steering avoidance condition is met but the right steering avoidance condition is not met, the DSECU adopts the collision avoidance predicted trajectory RO1 as the avoidance target trajectory for the right front end RFr of the vehicle SV, and adopts the second steering start margin time T2 as the limit index value TTS.

[0116] (7) When both the rightward steering avoidance condition and the leftward steering avoidance condition are satisfied, the DSECU adopts the longer of the first steering start margin time T1 and the second steering start margin time T2 as the limit index value TTS. Furthermore, the DSECU adopts the collision avoidance predicted trajectory corresponding to the longer of the first steering start margin time T1 and the second steering start margin time T2 as the avoidance target trajectory of the corresponding front end portion (left front end LFr or right front end RFr) of the host vehicle SV.

[0117] (8) The DSECU repeatedly executes the above processes (1) to (7) every time a predetermined time elapses, and determines whether or not the limit index value TTS has become 0. If the limit index value TTS has become 0, the DSECU further executes the following process.

[0118] (9) The DSECU determines whether the state of the turn indicator is a turn indication state based on the turn indicator information. When the DSECU determines that the state of the turn indicator is not a turn indication state, it changes the steering angle of the host vehicle SV so that "one of the right front end RFr and the left front end LFr of the host vehicle SV" that matches the collision avoidance predicted trajectory set as the avoidance target trajectory moves along the avoidance target trajectory. That is, it starts steering avoidance control. Note that, for convenience, the start time of this steering avoidance control when the collision avoidance predicted trajectory LO1 is adopted as the avoidance target trajectory is referred to as the "right direction normal time point." For convenience, the start time of this steering avoidance control when the collision avoidance predicted trajectory RO1 is adopted as the avoidance target trajectory is referred to as the "left direction normal time point."

[0119] (10) When the DSECU determines that the state of the turn indicator of the forward vehicle OV1 is a turn indicating state based on the turn indicator information and the avoidance target trajectory, the DSECU determines whether the direction indicated by the turn indicator of the forward vehicle OV1 is different from the planned avoidance direction of the host vehicle SV. When the DSECU determines that the direction indicated by the turn indicator is the same as the planned avoidance direction of the host vehicle SV, the DSECU prohibits (does not start) steering avoidance control.

[0120] (11) In response to this, when the DSECU determines that the state of the turn signal of the forward vehicle OV1 is in a turn indicating state based on the turn signal information and the avoidance target trajectory, and determines that the direction indicated by the turn signal of the forward vehicle OV1 is different from the planned avoidance direction of the host vehicle SV, the DSECU does not immediately start steering avoidance control, but further performs the following processing.

[0121] (11-1) When the planned avoidance direction is to the right (that is, when the rightward steering avoidance condition is satisfied but the leftward steering avoidance condition is not satisfied, and the collision avoidance predicted trajectory LO1 is adopted as the avoidance target trajectory) In this case, the DSECU determines the second position P2a to be the position obtained by moving the lateral position P2 of the right rear end of the leading vehicle OV1 at time tc1 in the negative direction along the vertical axis of the coordinate system in Figure 10 by a "predetermined corrected second distance smaller than the above-mentioned second distance d2."

[0122] Then, the DSECU uses this second position P2a to recalculate the collision avoidance predicted trajectory LO1 of the left front end LFr as the avoidance target trajectory, and further recalculate the first steering start margin time T1 (time until the steering start necessary time TS1) as the limit index value TTS every time a predetermined time has elapsed. The DSECU changes the steering angle of the host vehicle SV so that the left front end LFr moves along the avoidance target trajectory (collision avoidance predicted trajectory LO1) from the time point when the first steering start margin time T1 thus acquired becomes "0" (hereinafter referred to as "rightward delay time point" for convenience). That is, the steering avoidance control is started. This rightward delay time point is later in time than the above-mentioned rightward normal time point. In other words, the inter-vehicle distance between the host vehicle SV and the front vehicle OV1 at the rightward delay time point is shorter than the inter-vehicle distance between the host vehicle SV and the front vehicle OV1 at the rightward normal time point. Therefore, this modified example can reduce the possibility that the driver feels bothered by the steering avoidance control, as in the embodiment.

[0123] (11-2) When the planned avoidance direction is the left direction (that is, when the left steering avoidance condition is satisfied but the right steering avoidance condition is not satisfied, and the collision avoidance predicted trajectory RO1 is adopted as the avoidance target trajectory) In this case, the DSECU determines the first position P1a to be the position obtained by moving the lateral position P1 of the left rear end of the leading vehicle OV1 at time tc1 in the positive direction along the vertical axis of the coordinate system in Figure 10 by a "predetermined corrected first distance smaller than the above-mentioned first distance d1."

[0124] Then, the DSECU uses this first position P1a to recalculate the collision avoidance predicted trajectory RO1 of the right front end RFr as the avoidance target trajectory, and further recalculate the second steering start margin time T2 (time until the steering start necessary time TS2) as the limit index value TTS every time a predetermined time has elapsed. The DSECU changes the steering angle of the host vehicle SV so that the right front end RFr moves along the avoidance target trajectory (collision avoidance predicted trajectory RO1) from the time point when the second steering start margin time T2 thus acquired becomes "0" (hereinafter, for convenience, referred to as the "leftward delay time point"). That is, the steering avoidance control is started. This leftward delay time point is later in time than the above-mentioned leftward normal time point. In other words, the inter-vehicle distance between the host vehicle SV and the front vehicle OV1 at the leftward delay time point is shorter than the inter-vehicle distance between the host vehicle SV and the front vehicle OV1 at the leftward normal time point. Therefore, this modified example can reduce the possibility that the driver feels bothered by the steering avoidance control, as in the embodiment. [Explanation of symbols]

[0125] 10... collision avoidance support device, 20... driving support ECU, 21... surrounding sensor, 21a... radar sensor, 21b... camera sensor, 21c... target recognition unit, 22... vehicle speed sensor, 23... yaw rate sensor, 24... longitudinal acceleration sensor, 25... lateral acceleration sensor, 50... EPS ECU, 51... motor driver, 52... steering motor, SV... vehicle

Claims

1. A vehicle control device including a controller that controls an actuator for collision avoidance control to avoid a collision between a host vehicle and a forward vehicle when there is a high possibility of the collision, the vehicle control device comprising: The controller: Obtaining a planned direction of movement of the forward vehicle; prohibiting execution of the collision avoidance control when the planned movement direction of the preceding vehicle is the same direction as the planned avoidance direction of the host vehicle by the collision avoidance control; When the planned movement direction of the forward vehicle is different from the planned avoidance direction of the host vehicle by the collision avoidance control, a control start condition for starting the collision avoidance control is set so that the control start condition is satisfied at a later timing than when the planned movement direction of the forward vehicle is not acquired. It was configured as follows: Vehicle control device.

2. The vehicle control device according to claim 1, The controller: The planned movement direction of the forward vehicle is acquired based on a direction indicated by a turn indicator of the forward vehicle when the turn indicator is flashing. A vehicle control device configured as above.

3. The vehicle control device according to claim 2, When neither a left turn indicator among the direction indicators of the forward vehicle nor a right turn indicator among the direction indicators of the forward vehicle are in a blinking state, or when both the left turn indicator and the right turn indicator are in a blinking state, the planned movement direction of the forward vehicle is not acquired. Vehicle control device.

4. A vehicle control method for performing collision avoidance control for avoiding a collision between a host vehicle and a forward vehicle by controlling an actuator for the collision avoidance control, when there is a high possibility of the collision, comprising: obtaining a planned moving direction of the forward vehicle; prohibiting execution of the collision avoidance control when a planned movement direction of the preceding vehicle is the same direction as a planned avoidance direction of the host vehicle by the collision avoidance control; When the planned movement direction of the forward vehicle is different from the planned avoidance direction of the host vehicle by the collision avoidance control, setting a control start condition so that the control start condition for starting the collision avoidance control is satisfied at a later timing than when the planned movement direction of the forward vehicle is not acquired; A vehicle control method comprising:

5. A program to be executed by a computer mounted on a vehicle to execute a collision avoidance control for avoiding a collision between the vehicle and a forward vehicle by controlling an actuator for the collision avoidance control, when there is a high possibility of the collision between the vehicle and a forward vehicle, the program comprising: The program includes: obtaining a planned moving direction of the forward vehicle; prohibiting execution of the collision avoidance control when a planned movement direction of the preceding vehicle is the same direction as a planned avoidance direction of the host vehicle by the collision avoidance control; When the planned movement direction of the forward vehicle is different from the planned avoidance direction of the host vehicle by the collision avoidance control, setting a control start condition so that the control start condition for starting the collision avoidance control is satisfied at a later timing than when the planned movement direction of the forward vehicle is not acquired; A program that executes the following.

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