Vehicle driving assistance device

Abstract

To provide a driving support device for a vehicle, capable of ensuring sufficient safety even when an oncoming vehicle or the like suddenly enters a travel lane of an own vehicle.SOLUTION: A travel_ECU 14 recognizes an oncoming moving body O on the basis of travel environment information, acquires the distribution characteristics of a lateral position x associated with the movement of the oncoming moving body O, variably sets a risk determination region for calculating a smaller risk degree R as a distance from the center of an oncoming lane outward in the width direction of the oncoming moving body O becomes larger, in such a manner that a relatively larger risk degree R is calculated as the distribution characteristics of the lateral position x tend to disperse, calculates the risk degree R with respect to the oncoming moving body O according to the overlapping state of a target travel path Rm of an own vehicle M and the risk determination region, recognizes the oncoming moving body O as an obstacle according to the risk degree R, and performs preliminary collision avoidance control prior to emergency collision avoidance control, with respect to the oncoming moving body O recognized as the obstacle.SELECTED DRAWING: Figure 8

Description

[Technical Field]

[0001] The present invention relates to a driving assistance device for a vehicle that has a function of performing collision avoidance control against an obstacle. [Background technology]

[0002] Conventionally, in vehicles such as automobiles, driving assistance devices for assisting a driver in driving operations have been put into practical use in order to reduce the burden of driving operations on the driver and to improve safety. This type of driving assistance device has set driving modes, for example, a manual driving mode in which steering and acceleration / deceleration are performed according to the driver's proactive driving operations, a driving assistance mode in which steering assistance control and acceleration / deceleration control are performed on the premise that the driver actively drives the vehicle, and a driving assistance mode (so-called automatic driving mode) in which the vehicle runs without the need for driver's driving operations.

[0003] The driving assistance control in each driving assistance mode is basically realized by providing an adaptive cruise control (ACC) function, an active lane keep centering control (ALKC) function, etc. Such driving assistance control enables the vehicle to travel in the driving lane while maintaining a distance from the preceding vehicle.

[0004] Furthermore, various technologies relating to active safety of driving assistance devices have been proposed for performing control to avoid collisions with obstacles present ahead of the vehicle's path of travel (see, for example, Patent Document 1). In the technology of Patent Document 1, a collision prediction unit identifies an estimated collision area with an obstacle based on the vehicle's travel trajectory (target path of travel) and the position, shape, movement direction, etc. of the obstacle. The collision prediction unit also accumulates a collision probability value with the obstacle in the estimated collision area. Then, when the accumulated value of the collision probability value becomes large in any of one or more estimated collision areas identified at multiple points in time, a collision determination unit generates a warning signal. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-224501 Summary of the Invention [Problem to be solved by the invention]

[0006] However, an oncoming vehicle traveling in an oncoming lane adjacent to the host vehicle's lane is generally located at a distance in the vehicle width direction from the target travel path of the host vehicle. Therefore, the oncoming vehicle may not be a target of collision avoidance control. In this case, for example, if an oncoming vehicle suddenly enters the host vehicle's lane due to carelessness of the driver of the oncoming vehicle, it may be difficult to achieve sufficient collision avoidance control for the oncoming vehicle.

[0007] An object of the present invention is to provide a vehicle driving assistance device that can ensure sufficient safety even when an oncoming vehicle or the like suddenly enters the lane in which the vehicle is traveling. [Means for solving the problem]

[0008] A driving assistance device for a vehicle according to one aspect of the present invention includes a driving environment recognition unit that recognizes driving environment information outside the vehicle, and an obstacle recognition unit that recognizes obstacles that exist on a target traveling path of the vehicle based on the driving environment information. When it is determined that the collision prediction time between the host vehicle and the obstacle is smaller than a preset threshold value and the host vehicle is highly likely to collide with the obstacle, an emergency collision avoidance control unit that performs emergency collision avoidance control to avoid a collision with the obstacle; an oncoming moving object recognition unit that recognizes an oncoming moving object that moves on an oncoming lane adjacent to the driving lane of the host vehicle with a speed component in the opposite direction to the traveling direction of the host vehicle based on the driving environment information; a lateral position distribution characteristic acquisition unit that acquires a distribution characteristic of the lateral position of the oncoming moving object accompanying the movement of the oncoming moving object by setting the lateral position of the oncoming moving object relative to the host vehicle when the oncoming moving object is first detected as a reference lateral position, calculating an amount of change in the lateral position from the reference lateral position at each set period, and using the amount of change in the lateral position; and a lane width between the driving lane and the oncoming lane. It was set by Lane width direction and the above pair Direction From the time when the moving object is first detected until the time when the oncoming moving object approaches the host vehicle The lane direction is set by a risk determination area setting unit that sets a region as a risk determination area and calculates a risk level that decreases as the distance from the center of the oncoming lane toward both outer sides in the width direction of the road increases in the risk determination area based on the distribution characteristics of the lateral position; penetrates The risk assessment area The risk level set to the degree of risk to the host vehicle from the oncoming moving object; as and a pre-collision avoidance control unit that recognizes the oncoming moving body as an obstacle according to the risk level of the oncoming moving body relative to the vehicle, and performs pre-collision avoidance control prior to the emergency collision avoidance control for the oncoming moving body recognized as the obstacle, wherein the risk determination area setting unit calculates a higher risk level as the sway width of the oncoming moving body increases and the distribution characteristics of the lateral position tend to be more dispersed. [Effects of the Invention]

[0009] According to the vehicle driving assistance device of the present invention, sufficient safety can be ensured even when an oncoming vehicle or the like suddenly enters the lane in which the vehicle is traveling. [Brief explanation of the drawings]

[0010] [Figure 1] Schematic diagram of the driving assistance device [Figure 2] FIG. 1 is an explanatory diagram showing the monitoring areas of a stereo camera and a radar; [Figure 3] FIG. 10 is an explanatory diagram showing an obstacle present ahead of the target travel path of the host vehicle. [Figure 4] An explanatory diagram showing an oncoming moving object in an oncoming lane [Figure 5] FIG. 10 is an explanatory diagram showing the locus of a representative point of an opposing moving object; [Figure 6] FIG. 10 is an explanatory diagram showing the relationship between the target travel path of the host vehicle and the risk determination area of ​​an oncoming moving object. [Figure 7] Flowchart showing a preliminary collision avoidance control routine [Figure 8] Flowchart showing a risk level calculation subroutine [Figure 9] Flowchart showing the risk level upper limit processing subroutine [Figure 10] Flowchart showing a risk level reduction processing subroutine [Figure 11] Flowchart showing forced control intervention determination subroutine [Figure 12] An explanatory diagram illustrating a case where the risk level of an oncoming moving object increases due to factors other than sway. [Figure 13] An explanatory diagram illustrating a case where the risk level of an oncoming moving object increases due to factors other than sway. [Figure 14] An explanatory diagram illustrating a case where the risk level of an oncoming moving object increases due to factors other than sway. [Figure 15] FIG. 10 is an explanatory diagram illustrating the control content of preliminary collision avoidance control. DETAILED DESCRIPTION OF THE INVENTION

[0011] An embodiment of one aspect of the present invention will be described in detail below with reference to the drawings. Note that in the drawings used in the following description, each component is shown at a different scale so that it can be recognized. Therefore, the present invention is not limited to the number of components, the shapes of the components, the size ratios of the components, and the relative positional relationships of the components shown in these drawings.

[0012] As shown in FIGS. 1 and 2, the driving assistance device 1 includes a camera unit 10 fixed to the center of the front and upper part of the interior of a vehicle (host vehicle) M, for example.

[0013] The camera unit 10 includes a stereo camera 11, an image processing unit (IPU) 12, an image recognition unit (image recognition_ECU) 13, and a driving control unit (driving_ECU) 14.

[0014] The stereo camera 11 has a main camera 11a and a sub-camera 11b. The main camera 11a and the sub-camera 11b are configured, for example, with a CMOS or the like. The main camera 11a and the sub-camera 11b are arranged at positions symmetrical on either side of the center in the vehicle width direction.

[0015] The main camera 11a and the sub-camera 11b capture stereo images of the driving environment in the area Af (see FIG. 2) outside the vehicle from different viewpoints. The imaging cycles of the main camera 11a and the sub-camera 11b are synchronized with each other.

[0016] The IPU 12 performs predetermined image processing on the driving environment images captured by the stereo camera 11. As a result, the IPU 12 detects the edges of various objects, such as three-dimensional objects and road markings, displayed on the images. The IPU 12 then calculates distance information from the positional deviation of corresponding edges on the left and right images. As a result, the IPU 12 generates image information (distance image information) that includes distance information.

[0017] Based on the distance image information received from the IPU 12, the image recognition_ECU 13 calculates the road curvature [1 / m] of the marking lines that divide the left and right lanes (the lane on which the vehicle M is traveling) and the width between the left and right marking lines (lane width). The image recognition_ECU 13 also calculates the road curvature and the width between the left and right marking lines of lanes adjacent to the lane on which the vehicle M is traveling. Various methods are known for calculating the road curvature and lane width. For example, the image recognition_ECU 13 performs a binarization process based on the brightness of each pixel on the distance image. This process allows the image recognition_ECU 13 to extract marking line candidate points on the road. The image recognition_ECU 13 also performs curve approximation using the least squares method on the sequence of extracted marking line candidate points. This process allows the image recognition_ECU 13 to calculate the curvature of the left and right marking lines for each predetermined section. The image recognition_ECU 13 then calculates the lane width from the difference between the curvatures of the left and right marking lines.

[0018] Then, the image recognition_ECU 13 calculates the lane center and the lateral position deviation of the host vehicle M based on the curvature of the left and right lane markings and the lane width. Here, the lateral position deviation of the host vehicle M is the distance from the lane center to the center of the host vehicle M in the vehicle width direction.

[0019] Furthermore, the image recognition_ECU 13 performs predetermined pattern matching on the distance image information, thereby recognizing three-dimensional objects such as guardrails, curbs, medians, and surrounding vehicles that extend along the road. Here, the recognition of three-dimensional objects by the image recognition_ECU 13 includes recognition of, for example, the type of the three-dimensional object, the distance to the three-dimensional object, the speed of the three-dimensional object, and the relative speed between the three-dimensional object and the host vehicle M.

[0020] The various pieces of information recognized by the image recognition_ECU 13 are output to the traveling_ECU 14 as traveling environment information.

[0021] Thus, in this embodiment, the image recognition_ECU 13, together with the stereo camera 11 and the IPU 12, corresponds to a specific example of a driving environment recognition unit that recognizes driving environment information outside the vehicle.

[0022] The traveling_ECU 14 is a control unit for controlling the driving assistance device 1 in an integrated manner.

[0023] This traveling_ECU 14 is connected to various control units, such as a cockpit control unit (CP_ECU) 21, an engine control unit (E / G_ECU) 22, a transmission control unit (T / M_ECU) 23, a brake control unit (BK_ECU) 24, and a power steering control unit (PS_ECU) 25, via an in-vehicle communication line such as a CAN (Controller Area Network).

[0024] Furthermore, the travel_ECU 14 is connected with various sensors, such as a locator unit 36, a left front side sensor 37lf, a right front side sensor 37rf, a left rear side sensor 37lf, and a right rear side sensor 37rr.

[0025] A human-machine interface (HMI) 31 arranged near the driver's seat is connected to the CP_ECU 21. The HMI 31 includes, for example, an operation switch for setting and executing various driving assistance controls, a mode selector switch for switching driving assistance modes, a steering touch sensor for detecting the driver's steering state, a turn signal switch, a driver monitoring system (DMS) for performing face authentication and line of sight detection of the driver, a touch panel display, a combination meter, and a speaker.

[0026] When the CP_ECU 21 receives a control signal from the driving_ECU 14, it appropriately notifies the driver of various information regarding various warnings for preceding vehicles, the implementation status of driving assistance control, and the driving environment of the vehicle M, by displaying or audibly displaying via the HMI 31.

[0027] In addition, the CP_ECU 25 outputs various input information to the driving_ECU 14, such as the on / off operation status of various driving assistance controls input by the driver through the HMI 31, the set vehicle speed (set vehicle speed) Vs for the vehicle M, and the operation status of the turn signal switch.

[0028] The output side of the E / G_ECU 22 is connected to a throttle actuator 32 of an electronically controlled throttle, etc. The input side of the E / G_ECU 22 is connected to various sensors such as an accelerator sensor (not shown).

[0029] The E / G_ECU 22 controls the operation of the throttle actuator 32 based on a control signal from the travel_ECU 14 or detection signals from various sensors. In this way, the E / G_ECU 22 adjusts the amount of intake air into the engine to generate a desired engine output. The E / G_ECU 22 also outputs signals such as the accelerator opening detected by the various sensors to the travel_ECU 14.

[0030] An output side of the T / M_ECU 23 is connected to a hydraulic control circuit 33. Furthermore, various sensors such as a shift position sensor (not shown) are connected to an input side of the T / M_ECU 23. The T / M_ECU 23 performs hydraulic control for the hydraulic control circuit 33 based on an engine torque signal estimated by the E / G_ECU 22 and detection signals from various sensors. As a result, the T / M_ECU 23 operates friction engagement elements, pulleys, and the like provided in the automatic transmission, and shifts the engine output at a desired gear ratio. Furthermore, the T / M_ECU 23 outputs signals such as the shift position detected by the various sensors to the travel_ECU 14.

[0031] A brake actuator 34 is connected to the output side of the BK_ECU 24. The brake actuator 34 adjusts the brake fluid pressure output to the brake wheel cylinders provided on each wheel. In addition, various sensors such as a brake pedal sensor, a yaw rate sensor, a longitudinal acceleration sensor, and a vehicle speed sensor (not shown) are connected to the input side of the BK_ECU 24.

[0032] The BK_ECU 24 performs drive control on the brake actuator 34 based on control signals from the travel_ECU 14 or detection signals from various sensors. As a result, the BK_ECU 24 appropriately generates braking force on each wheel to perform forced braking control, yaw rate control, etc. on the host vehicle M. In addition, the BK_ECU 24 outputs signals of the brake operation state, yaw rate, longitudinal acceleration, vehicle speed (host vehicle speed), etc. detected by the various sensors to the travel_ECU 14.

[0033] An electric power steering motor 35 is connected to the output side of the PS_ECU 25. The electric power steering motor 35 applies steering torque to the steering mechanism by the rotational force of the motor. In addition, various sensors such as a steering torque sensor and a steering angle sensor are connected to the input side of the PS_ECU 25.

[0034] The PS_ECU 25 controls the drive of the electric power steering motor 35 based on control signals from the travel_ECU 14 or detection signals from various sensors. As a result, the PS_ECU 25 generates a steering torque for the steering mechanism. The PS_ECU 25 also outputs signals of the steering torque, steering angle, etc. detected by the various sensors to the travel_ECU 14.

[0035] The locator unit 36 ​​includes a GNSS sensor 36a and a high-precision road map database (road map DB) 36b.

[0036] The GNSS sensor 36a receives positioning signals transmitted from a plurality of positioning satellites to determine the position (latitude, longitude, altitude, etc.) of the vehicle M.

[0037] The road map DB 36b is a large-capacity storage medium such as an HDD. High-precision road map information (dynamic map) is stored in this road map DB 36b. The road map information includes, for example, lane data required for autonomous driving, such as lane width data, lane center position coordinate data, lane travel azimuth data, and speed limit data. The lane data is stored at intervals of several meters for each lane on the road map. For example, based on a request signal from the traveling_ECU 14, the road map DB 36b outputs road map information of a set range based on the vehicle position measured by the GNSS sensor 36a to the traveling_ECU 14 as traveling environment information.

[0038] Thus, in this embodiment, the road map DB 36b, together with the GNSS sensor 36a, corresponds to a specific example of a driving environment recognition unit that recognizes driving environment information outside the vehicle.

[0039] The left front side sensor 37lf and the right front side sensor 37rf are configured by, for example, millimeter-wave radars. These left front side sensor 37lf and right front side sensor 37rf are disposed, for example, on the left and right sides of the front bumper, respectively. The left front side sensor 37lf and the right front side sensor 37rf detect, as driving environment information, three-dimensional objects present in areas Alf, Arf (see FIG. 2) diagonally forward and to the left and right of the vehicle M, which are difficult to recognize in the image from the stereo camera 11.

[0040] The left rear side sensor 37lr and the right rear side sensor 37rr are configured, for example, by millimeter-wave radar. The left rear side sensor 37lr and the right rear side sensor 37rr are disposed, for example, on the left and right sides of the rear bumper, respectively. The left rear side sensor 37lf and the right rear side sensor 37rf detect, as driving environment information, three-dimensional objects present in areas Alr, Arr (see FIG. 2) diagonally to the left and right sides and rear of the vehicle M that are difficult to recognize with the left front side sensor 37lf and the right front side sensor 37rf.

[0041] Here, when each radar is configured as a millimeter wave radar, the millimeter wave radar mainly detects three-dimensional objects such as adjacent vehicles and following vehicles by analyzing the waves reflected from the objects in response to the output radio waves. Specifically, each radar detects information about the three-dimensional object, such as the width of the three-dimensional object, the position of a representative point of the three-dimensional object (the relative position with respect to the vehicle M), and the speed.

[0042] Thus, in this embodiment, the left front side sensor 37lf, the right front side sensor 37rf, the left rear side sensor 37lr, and the right rear side sensor 37rr correspond to a specific example of a driving environment recognition unit that recognizes driving environment information outside the vehicle.

[0043] In addition, the coordinates of each object outside the vehicle contained in the driving environment information recognized by the image recognition_ECU 13, the locator unit 36, the left front side sensor 37lf, the right front side sensor 37rf, the left rear side sensor 37lf, and the right rear side sensor 37rr are all converted in the driving_ECU 14 into coordinates of a three-dimensional coordinate system (see Figure 2) with the center of the vehicle M as the origin, for example.

[0044] The driving modes set in the travel_ECU 14 include a manual driving mode, a first driving control mode and a second driving control mode for driving control, and an evacuation mode. These driving modes can be selectively switched in the travel_ECU 14 based on, for example, the operation status of a mode selector switch provided in the HMI 31.

[0045] Here, the manual driving mode is a driving mode that requires the driver to maintain steering, i.e., the manual driving mode is a driving mode in which the host vehicle M is driven according to driving operations such as steering, accelerator, and brake operations by the driver.

[0046] The first driving control mode is also a driving mode that requires the driver to maintain steering. That is, the first driving control mode is a so-called semi-automatic driving mode in which the host vehicle M is driven while reflecting the driving operation by the driver. This first driving control mode is realized, for example, by the driving_ECU 14 outputting various control signals to the E / G_ECU 22, the BK_ECU 24, and the PS_ECU 25. In the first driving control mode, mainly, adaptive cruise control (ACC), active lane keep centering control (ALKC), active lane keep bouncing control (ALKB), lane change control, and the like are appropriately combined. This enables the host vehicle M to travel along a target driving route. Furthermore, in the first driving control mode, lane change control can also be performed when the driver operates a turn signal switch.

[0047] Here, the following inter-vehicle distance control is basically performed based on the traveling environment information input from the image recognition_ECU 13 and the like.

[0048] Specifically, when a preceding vehicle is recognized ahead of the host vehicle M by the image recognition_ECU 13 or the like, the traveling_ECU 14 performs follow-up travel control as part of follow-up inter-vehicle distance control. In this follow-up travel control, the traveling_ECU 14 sets a target inter-vehicle distance Lt and a target vehicle speed Vt based on the vehicle speed Vl of the preceding vehicle, etc. Then, the traveling_ECU 14 performs acceleration / deceleration control for the host vehicle M based on the target inter-vehicle distance Lt and the target vehicle speed Vt. As a result, the traveling_ECU 14 basically causes the host vehicle M to travel following the preceding vehicle while maintaining the inter-vehicle distance L at the target inter-vehicle distance Lt and the vehicle speed V at the target vehicle speed Vt.

[0049] On the other hand, when, for example, the image recognition_ECU 14 or the like does not recognize a preceding vehicle ahead of the host vehicle M, the travel_ECU 14 performs constant speed traveling control as part of the follow-up inter-vehicle distance control. In this constant speed traveling control, the travel_ECU 14 sets the set vehicle speed Vs input by the driver as the target vehicle speed Vt. Then, the travel_ECU 14 performs acceleration / deceleration control on the host vehicle M based on the target vehicle speed Vt. In this way, the travel_ECU 14 maintains the vehicle speed V of the host vehicle M at the set vehicle speed Vs.

[0050] Furthermore, the lane centering control and lane departure suppression control are basically performed based on driving environment information input from at least one of the image recognition_ECU 13 and the locator unit 36. That is, the driving_ECU 14 sets a target travel path Rm along the left and right lane markings in the center of the host vehicle's driving lane based on, for example, lane marking information included in the driving environment information. Then, the driving_ECU 14 maintains the host vehicle M in the center of the lane by performing feedforward control and feedback control on steering based on the target travel path Rm. Furthermore, when the driving_ECU 14 determines that the host vehicle M is likely to deviate from the host vehicle's driving lane due to the influence of a crosswind, a cant of the road, or the like, the driving_ECU 14 suppresses lane departure by forcible steering control.

[0051] The lane change control is basically performed based on driving environment information input from the image recognition_ECU 13, the left front side sensor 37lf, the right front side sensor 37rf, the left rear side sensor 37lr, and the right rear side sensor 37rr. This lane change control is executed, for example, when the driver operates the turn signal switch. That is, the driving_ECU 14 recognizes an adjacent lane that exists in the direction of operation of the turn signal switch based on the driving environment information. The driving_ECU 14 also recognizes whether or not there is a vehicle or the like on the adjacent lane that may obstruct the lane change. Then, when the driving_ECU 14 determines that there is space on the adjacent lane where a lane change is possible, it performs a lane change to the adjacent lane. This lane change control is performed in coordination with the following vehicle distance control.

[0052] The second driving control mode is a driving mode in which the host vehicle M travels without the driver needing to maintain steering, operate the accelerator, or operate the brakes. In other words, the second driving control mode is a so-called automatic driving mode in which the host vehicle M travels autonomously without the driver needing to perform any driving operation. This second driving control mode is realized, for example, by the driving_ECU 14 outputting various control signals to the E / G_ECU 22, the BK_ECU 24, and the PS_ECU 25. In the second driving control mode, a preceding vehicle following control, a lane centering control, a lane departure prevention control, and the like are mainly performed in appropriate combination. This enables the host vehicle M to travel along a target route (route map information). Furthermore, in the second driving control mode, lane change control can also be performed. Note that in the second driving control mode, lane change control is automatically performed as appropriate in accordance with the driving route to the destination set for the host vehicle M, driving environment information, and the like, even when the driver does not operate the turn signal switch.

[0053] The evacuation mode is a mode for automatically stopping the host vehicle M on a shoulder strip, etc. This evacuation mode is executed, for example, when, while traveling in the second driving control mode, it becomes impossible to continue traveling in that mode and the driver cannot take over driving operation (i.e., when it is not possible to transition to the manual driving mode or the first driving control mode).

[0054] Furthermore, in each of the above-described driving modes, the travel_ECU 14 appropriately performs emergency collision avoidance control for obstacles such as vehicles that are highly likely to collide with the host vehicle M. This emergency collision avoidance control includes, for example, emergency braking control (autonomous emergency braking (AEB)) and emergency steering control.

[0055] Emergency braking control is basically control for avoiding a collision with an obstacle existing ahead on the target travel route Rm of the host vehicle M by braking. During emergency braking control, the travel ECU 14 sets a target travel area Am ahead of the host vehicle M, for example, as shown in FIG. 3. This target travel area Am has a predetermined width (for example, greater than or equal to the vehicle width of the host vehicle M) centered on the target travel route Rm. Further, the travel ECU 14 detects obstacles such as a preceding vehicle or a parked vehicle existing on the target travel area Am based on the travel environment information. Furthermore, the travel ECU 14 calculates a longitudinal collision prediction time (vertical collision prediction time) TTCz of the host vehicle M as a collision prediction time with respect to the obstacle. This vertical collision prediction time TTCz is calculated based on the relative speed and relative distance between the host vehicle M and the obstacle.

[0056] Then, when the longitudinal collision prediction time TTCz becomes smaller than a first threshold value Tth1 set in advance, the travel ECU 14 executes primary braking control. When the primary braking control is started, the travel ECU 14 decelerates the host vehicle M using a first target deceleration a1 set in advance (for example, 0.4G).

[0057] Furthermore, when the longitudinal collision prediction time TTCz becomes smaller than a second threshold value Tth2 (where Tth2 < Tth1) set in advance, the travel ECU 14 executes secondary braking control. When the secondary braking control is started, the travel ECU 14 decelerates the host vehicle M using a second target deceleration a2 set in advance (for example, 1G) until the relative speed with respect to the obstacle becomes "0".

[0058] Emergency steering control is control for avoiding a collision with an obstacle existing ahead on the target travel route of the host vehicle M by steering. The travel ECU 14 executes emergency steering control instead of or in combination with the emergency braking control when it is determined that the collision with the obstacle cannot be avoided by the secondary braking control, for example.

[0059] Specifically, when the longitudinal collision prediction time TTCz becomes smaller than a third threshold value Tth3 (where Tth3 < Tth2) set in advance, the traveling ECU 14 executes emergency steering control (for example, refer to the host vehicle M' in FIG. 3).

[0060] During this emergency steering control, the traveling ECU 14 sets a target lateral position on the side of the obstacle. Further, the traveling ECU 14 sets a new target travel path Ravo until the host vehicle M reaches the target lateral position. This new target travel path Ravo is set by dividing, for example, an extension section for avoiding the host vehicle M to the side of the obstacle and a return section for restoring the attitude of the host vehicle M in the direction along the host vehicle travel path. Then, the traveling ECU 14 executes steering control along the new target travel path Ravo.

[0061] Note that the traveling ECU 14 can also variably set the first to third threshold values Tth1 to Tth3 according to the wrap rate in the vehicle width direction of the obstacle with respect to the host vehicle M. This wrap rate Rr is calculated based on, for example, the intrusion amount of the obstacle into the target travel area Am. Then, the traveling ECU 14 sets, for example, using a preset map or the like, such that the first to third threshold values Tth1 to Tth3 become larger as the wrap rate Rr increases.

[0062] Incidentally, when the host vehicle M is traveling on a road without a median strip, a case is assumed where an oncoming moving object O existing in the oncoming lane suddenly intrudes into the travel lane of the host vehicle M. Here, in the present embodiment, the oncoming moving object O refers to an oncoming vehicle (including a two-wheeled vehicle) or a pedestrian that moves with a speed component in the direction opposite to the moving direction of the host vehicle M. To realize collision avoidance with such an oncoming moving object O, the traveling ECU 14 of the present embodiment also extends and applies emergency collision avoidance control to the oncoming moving object O that intrudes from the oncoming lane of the road without a median strip into the travel lane of the host vehicle M.

[0063] Prior to the emergency collision avoidance control for the oncoming moving object O, the travel_ECU 14 appropriately performs preliminary collision avoidance control (preliminary collision avoidance control) as necessary. This preliminary collision avoidance control is a control for suppressing in advance the risk of collision between the oncoming moving object O and the host vehicle M.

[0064] To execute the preliminary collision avoidance control, the traveling_ECU 14 determines, based on the traveling environment information, whether or not a median strip exists on the road separating the traveling lane of the host vehicle M from the oncoming lane. If no median strip exists on the road on which the host vehicle M is traveling, the traveling_ECU 14 detects, for example, an oncoming moving object O moving on the oncoming lane (see FIG. 4). When the oncoming moving object O is detected, the traveling_ECU 14 calculates a longitudinal velocity component Voz and a lateral velocity component Vox corresponding to the longitudinal direction and the vehicle width direction of the host vehicle M based on the speed Vo of the oncoming moving object O.

[0065] In addition, the travel_ECU 14 calculates the predicted time of collision with the oncoming moving object O, that is, the predicted time of collision in the front-to-rear direction of the host vehicle M (predicted time of longitudinal collision) TTCz and the predicted time of collision in the vehicle width direction of the host vehicle M (predicted time of lateral collision) TTCx.

[0066] That is, the traveling_ECU14 calculates the longitudinal collision prediction time TTCz, for example, by dividing the longitudinal relative speed calculated from the vehicle speed V of the host vehicle M and the longitudinal speed component Voz of the oncoming moving body O by the longitudinal relative distance between the host vehicle M and the oncoming moving body O.

[0067] Furthermore, the travel_ECU 14 calculates the predicted time to lateral collision TTCx, for example, by dividing the lateral velocity component Vx of the oncoming moving object O by the distance from the oncoming moving object O to the target traveling region Am. When calculating this predicted time to lateral collision TTVx, it is desirable that the distance from the oncoming moving object O to the target traveling region Am be corrected based on the width of the oncoming moving object O and the approach angle (predicted collision angle) of the moving object O with respect to the target traveling region Am.

[0068] Furthermore, the travel_ECU 14 calculates a risk level R as a parameter indicating the possibility (risk) of the oncoming moving object O colliding with the host vehicle M.

[0069] When calculating the risk level R, the travel_ECU 14 sets a risk determination region. Lane width direction teeth, It is set to the total width of the lane of the vehicle M and the oncoming lane. The lane direction of the risk determination area is set to the area from when the oncoming moving object O is first detected until the oncoming moving object O approaches the vehicle M. The risk level R is calculated as follows: For example, the risk determination area is set so as to extend from the center of the oncoming lane in the width direction of the road. The risk determination area is an area for calculating a risk level R that varies depending on the distance from the center of the oncoming moving object O outward in the width direction of the oncoming moving object O, as shown in FIG. 6, for example. For example, in the risk determination area shown in FIG. 6, four small areas are set in order from the center of the oncoming lane, consisting of a "danger area," a "warning area," a "caution area," and a "safe area." Then, risk levels R of "9," "4," "2," and "0" are set for each small area so that the risk level R gradually decreases as the distance from the oncoming moving object O increases.

[0070] The widths of the danger area, alert area, caution area, and safety area are set variably depending on the state of swaying of the oncoming moving object O. The width of each of these small areas is set based on statistical results as to whether or not the oncoming moving object O is prone to swaying.

[0071] Specifically, the traveling_ECU 14 sets the lateral position x relative to the host vehicle M when the oncoming moving object O is first detected as a reference lateral position x0 (see FIG. 5). The traveling_ECU 14 also calculates a change Δx in the lateral position x of the oncoming moving object O relative to the reference lateral position x0 for each set period. The traveling_ECU 14 then acquires the distribution characteristics of the lateral position of the oncoming moving object O using the change Δx in the lateral position x calculated for each set period.

[0072] The distribution characteristic of this lateral position can be expressed, for example, by expressing the change Δx of the lateral position x of the oncoming moving object O relative to the reference lateral position x0 as follows: As shown in FIG. 5, from the time when the oncoming moving object O is first detected until the oncoming moving object O approaches the host vehicle M, predetermined Every cycle Amount of change floor6, the risk level R and the histogram are generated based on the behavior of the oncoming moving object O shown in FIG. The histogram shown in the top row of Fig. 6 is a compilation of the amount of change Δx in the vicinity of the first detection of the oncoming moving object O. The histogram shown in the bottom row of Fig. 6 is a compilation of the amount of change Δx in the lateral position x sampled from the first detection of the oncoming moving object O to the present. The distribution characteristics of the lateral position x are generally normal distributions. The normal distribution of the distribution characteristics of the lateral position x becomes more dispersed (the distribution width Wx becomes wider) as the fluctuation of the oncoming moving object O increases, and becomes more convergent (the distribution width Wx becomes narrower) as the fluctuation of the oncoming moving object O decreases.

[0073] Based on such distribution characteristics of the lateral position x, the travel_ECU 14 variably sets the width of each small region by referring to a preset map or the like. Specifically, the travel_ECU 14 sets each small region so that the smaller region on the danger side expands in the road width direction as the distribution width Wx of the lateral position x becomes wider (i.e., the distribution characteristics of the lateral position x tend to be more dispersed), and the smaller region on the safety side contracts in the road width direction. Note that, for example, as shown in FIG. 6, when the small region on the danger side expands, the small regions on the safety side gradually disappear.

[0074] 5 and 6, the oncoming moving object O is moving with a large amount of swaying. Therefore, as the oncoming moving object O approaches the host vehicle M, the distribution characteristics of the lateral position x tend to become more dispersed. As a result, the small area on the dangerous side gradually expands in the risk determination area.

[0075] Here, the width of each small region is, for example, the well-known sample variance S 2 It is also possible to set it variably based on the

[0076] Once the risk determination area is set, the travel_ECU 14 calculates the risk level R for the oncoming moving object O according to the overlap state between the target traveling path Rm of the host vehicle M and the risk determination area. That is, the travel_ECU 14 sets the risk level R of the small area that the target traveling path Rm passes through as the risk level R for the current oncoming moving object O. As is clear from FIG. 6 , the risk level R increases as the oncoming moving object O moves toward the traveling lane of the host vehicle M due to, for example, swaying of the oncoming moving object O. Possible causes of swaying of the oncoming moving object O include, for example, drowsiness, inattentiveness, and incorrect operation of the driver of the oncoming moving object O.

[0077] Based on the risk level R calculated in this manner, the travel_ECU 14 determines whether or not the oncoming moving object O is an obstacle that may collide with the host vehicle M. Then, when the oncoming moving object O is recognized as an obstacle, the travel_ECU 14 appropriately executes preliminary collision avoidance control for the oncoming moving object O prior to emergency collision avoidance control.

[0078] Thus, in this embodiment, the traveling_ECU14 corresponds to a specific example of an obstacle recognition unit, an emergency collision avoidance control unit, an oncoming moving object recognition unit, a lateral position distribution characteristic acquisition unit, a risk judgment area setting unit, a risk level calculation unit, and a preliminary collision avoidance control unit.

[0079] Next, details of the preliminary collision avoidance control will be described with reference to a flowchart of a preliminary collision avoidance control routine shown in Fig. 7. This preliminary collision avoidance control routine is repeatedly executed at set time intervals by the travel_ECU 14 when the host vehicle M is traveling on a road without a central reservation.

[0080] When the routine starts, the traveling_ECU 14 checks in step S101 whether or not an oncoming moving object O is present on the oncoming lane.

[0081] Then, in step S101, if it is determined that an oncoming moving object O does not exist on the oncoming lane (step S101: NO), the traveling_ECU 14 exits the routine.

[0082] On the other hand, in step S101, if it is determined that an oncoming moving object O is present on the oncoming lane (step S101: YES), the traveling_ECU 14 proceeds to step S102.

[0083] In step S102, the travel_ECU 14 calculates a predicted longitudinal collision time TTCz and a predicted lateral collision time TTCx with respect to the oncoming moving object O.

[0084] In the following step S103, the travel_ECU 14 calculates the risk level R for the oncoming moving object O. The calculation of this risk level R is performed, for example, according to a flowchart of a risk level calculation subroutine shown in FIG.

[0085] When the subroutine starts, the travel_ECU 14 recognizes the front wheels of the oncoming moving object O in step S201 if the oncoming moving object O is a four-wheeled vehicle or a two-wheeled vehicle.

[0086] In the following step S202, the travel_ECU 14 determines the center of the oncoming moving object O. That is, for example, if the oncoming moving object O is a four-wheeled vehicle, the travel_ECU 14 determines the tread center of the front wheel recognized in step S201 as the center of the oncoming moving object O. Also, for example, if the oncoming moving object O is a two-wheeled vehicle, the travel_ECU 14 determines the position of the front wheel recognized in step S201 as the center of the oncoming moving object O.

[0087] In the next step S203, the traveling_ECU 14 updates the histogram indicating the distribution of the lateral position of the oncoming moving object O. That is, the traveling_ECU 14 calculates, for example, the lateral position of the center of the oncoming moving object O determined this time as the current lateral position x of the oncoming moving object O on the road. The traveling_ECU 14 also calculates the amount of change Δx in the lateral position x relative to the reference lateral position X0. Then, the traveling_ECU 14 adds a frequency of "1" to the class corresponding to the amount of change Δx in the current lateral position x in the histogram generated up to the previous time.

[0088] In the following step S204, the traveling_ECU 14 calculates the distribution width Wx of the lateral position x of the oncoming moving object O based on the updated histogram.

[0089] In the following step S205, the traveling_ECU 14 acquires the target traveling path Rm set for the host vehicle M.

[0090] In the next step S206, the travel_ECU 14 sets a risk determination area on the road. That is, the travel_ECU 14 refers to a pre-set map or the like, and calculates a distribution width Wx of the lateral position x of the oncoming moving object O. The corresponding risk level R Risk Assessment Area to Set it up.

[0091] In the next step S207, the traveling_ECU 14 determines whether the risk determination area To, After calculating the risk level R of the oncoming moving object O, the subroutine is terminated. That is, the traveling_ECU 14 calculates the risk level R of the risk determination area through which the target travel path Rm of the host vehicle M passes as the risk level R of the oncoming moving object O.

[0092] 7, when the process proceeds from step S103 to step S104, the traveling_ECU 14 performs upper limit processing on the risk level R. This upper limit processing is processing to prevent the risk level R from becoming unnecessarily large due to factors other than the swaying of the oncoming moving object O.

[0093] In this upper limit process, if it is expected that the risk level R will increase due to factors other than the swaying of the oncoming moving object O, the travel_ECU 14 limits the risk level R to, for example, "4" or less.

[0094] The upper limit process for the risk level R is executed, for example, according to the flowchart of the risk level upper limit process subroutine shown in FIG.

[0095] When the subroutine starts, the traveling_ECU 14 acquires the target traveling path Rm set for the host vehicle M in step S301.

[0096] In the following step S302, the travel_ECU 14 calculates a predicted path Ro of the oncoming moving object O based on the current speed and moving direction of the oncoming moving object O.

[0097] In the following step S303, the traveling_ECU 14 calculates a predicted collision point Pc and a collision angle θc between the host vehicle M and the oncoming moving object O. For example, assuming that the oncoming moving object O has moved on the predicted path Ro (see O' in FIG. 4), the traveling_ECU 14 calculates a point where both the longitudinal collision prediction time TTCz and the lateral collision prediction time TTCx are equal to or less than "0" as the predicted collision point Pc between the host vehicle M and the oncoming moving object O (see FIG. 4). Furthermore, assuming that the oncoming moving object O has moved to the predicted collision point Pc, the traveling_ECU 14 calculates the collision angle θc based on the relative angle between the oncoming moving object O' after the movement and the host vehicle M.

[0098] In the following step S304, the travel_ECU 14 checks whether the blinker of the oncoming moving object O is flashing or not.

[0099] Then, in step S304, if it is determined that the blinker of the oncoming moving object O is blinking (step S304: YES), the traveling_ECU 14 proceeds to step S308.

[0100] In step S308, the traveling_ECU 14 performs upper limit processing to set the risk level R to, for example, "4" or less, and then exits the subroutine.

[0101] That is, for example, as shown in Fig. 12, a case where the risk level R of the oncoming moving object O increases due to factors other than swaying is assumed to be a case where the oncoming moving object O turns toward the driving lane of the host vehicle M while flashing its turn signal. In such a case, it is assumed that the intention of the driver driving the oncoming moving object O is clear and that the driver is fully aware of the host vehicle M. Therefore, in such a case, it is difficult to imagine that the oncoming moving object O will suddenly invade the driving lane of the host vehicle M at a timing when there is a high possibility of a collision with the host vehicle M, and therefore the control content is limited by the upper limit processing.

[0102] On the other hand, in step S304, if it is determined that the blinker of the oncoming moving object O is not blinking (step S304: NO), the traveling_ECU 14 proceeds to step S305.

[0103] In step S305, the traveling_ECU 14 checks whether the behavior of the oncoming moving object O has changed, compared to the previous time, in a favorable direction that makes it possible to avoid a collision with the host vehicle M. That is, the traveling_ECU 14 checks whether the predicted traveling path Ro of the oncoming moving object O calculated in step S302, and the predicted collision point Pc and collision angle θc with the oncoming moving object O calculated in step S303 have changed in a favorable direction. Here, for example, if the lateral velocity component Vox of the oncoming moving object O starts to decrease, the predicted traveling path Ro of the oncoming moving object O generally inclines toward the host vehicle M. Also, for example, if the lateral velocity component Vox of the oncoming moving object O starts to decrease, the predicted collision point Pc of the oncoming moving object O generally moves toward the host vehicle M. Also, for example, if the lateral velocity component Vox of the oncoming moving object O starts to decrease, the collision angle θc changes to increase. Therefore, the traveling_ECU14 determines that the behavior of the oncoming moving body O has changed to an advantageous side when at least one of the following occurs: the predicted path of travel Ro tilts toward the vehicle M, the collision prediction point Pc moves toward the vehicle M, or the collision angle θc changes to an increasing side.

[0104] Then, when the traveling_ECU 14 determines that the behavior of the oncoming moving object O has changed to the advantageous side (step S305: YES), the process proceeds to step S308.

[0105] In step S308, the traveling_ECU 14 performs upper limit processing to set the risk level R to "4" or less, for example, and then exits the subroutine.

[0106] On the other hand, in step S305, when it is determined that the behavior of the oncoming moving object O has changed to the unfavorable side (step S305: NO), the traveling_ECU 14 proceeds to step S306.

[0107] In step S306, the travel_ECU 14 checks whether or not a stationary object such as a parked vehicle exists near the oncoming moving object O on the oncoming lane.

[0108] Then, in step S306, if it is determined that a parked vehicle or the like is present on the oncoming lane (step S306: YES), the traveling_ECU 14 proceeds to step S308.

[0109] In step S308, the traveling_ECU 14 performs upper limit processing to set the risk level R to "4" or less, for example, and then exits the subroutine.

[0110] That is, for example, as shown in FIG. 13, a case where the risk level R of the oncoming moving body O increases due to factors other than swaying is assumed to be a case where the oncoming moving body O avoids a stationary object such as a parked vehicle in the oncoming lane. In such a case, it is assumed that the intention of the driver driving the oncoming moving body O is clear, and that the driver is fully aware of the host vehicle M. In addition, in such a case, it is assumed that the risk level R calculated based on the risk determination area will increase once and then quickly decrease. Therefore, in such a case, it is unlikely that the oncoming moving body O will suddenly invade the driving lane of the host vehicle M at the timing when there is a high possibility of a collision with the host vehicle M, and therefore the control content is limited by the upper limit processing.

[0111] On the other hand, if it is determined in step S306 that there is no parked vehicle or the like on the oncoming lane (step S306: NO), the travel_ECU 14 proceeds to step S307.

[0112] In step S307, the travel_ECU 14 checks whether the oncoming moving object O is merging from a branch road into an oncoming lane.

[0113] Then, in step S307, if it is determined that the oncoming moving object O is merging from a branch road (step S307: YES), the travel_ECU 14 proceeds to step S308.

[0114] In step S308, the traveling_ECU 14 performs upper limit processing to set the risk level R to "4" or less, for example, and then exits the subroutine.

[0115] That is, for example, as shown in FIG. 14, a case in which the risk level R of the oncoming moving object O increases due to factors other than swaying is assumed to be a case in which the oncoming moving object O intrudes into the oncoming lane from a branching road or the like. In such a case, it is assumed that the intention of the driver driving the oncoming moving object O is clear, and that the driver is fully aware of the host vehicle M. In addition, in such a case, it is assumed that the risk level R calculated based on the risk determination area will increase once and then quickly begin to decrease. Therefore, in such a case, it is unlikely that the oncoming moving object O will suddenly intrude into the driving lane of the host vehicle M at the time of collision with the host vehicle M, and therefore the control content is limited by upper limit processing.

[0116] On the other hand, if it is determined in step S307 that the oncoming moving object O is not merging from a branch road (step S307: NO), the travel_ECU 14 exits the subroutine as is.

[0117] In the main routine of FIG. 7, when proceeding from step S104 to step S105, the traveling ECU 14 performs a down - processing for the risk degree R. This down - processing is a process for appropriately lowering the risk level LV of the pre - collision avoidance control (described later) allowed according to the risk degree R based on the relative relationship between the host vehicle M and the oncoming moving object O. For example, even when the fluctuation of the oncoming moving object O is large and the risk degree R that the oncoming moving object O enters the traveling lane of the host vehicle M is high, if the oncoming moving object O is present far away, the possibility that the host vehicle M collides with the oncoming moving object O is low. Therefore, in such a case, the traveling ECU 14 lowers the risk level LV of the pre - collision avoidance control allowed according to the risk degree R in order to prevent the execution of excessive pre - collision avoidance control.

[0118] This down - processing is executed, for example, according to the flowchart of the down - processing sub - routine shown in FIG. 10.

[0119] When the sub - routine starts, the traveling ECU 14 checks whether the longitudinal collision prediction time TTCz for the oncoming moving object O is smaller than a fourth threshold value Tth4 (where Tth1 < Tth4) set in advance.

[0120] And in step S401, when it is determined that the longitudinal collision prediction time TTCz is equal to or greater than the fourth threshold value Tth4 (step S401: NO), the traveling ECU 14 proceeds to step S402.

[0121] In step S402, after permitting the pre-collision avoidance control corresponding to when the risk degree R is "2" or less, the traveling ECU 14 exits the subroutine. Thereby, the traveling ECU 14 permits up to the pre-collision avoidance control corresponding to when the risk degree R is "2", even if the current risk degree R is "9", for example. Also, the traveling ECU 14 permits the pre-collision avoidance control corresponding to when the risk degree R is "2" when the current risk degree R is "2", for example. In the present embodiment, the pre-collision avoidance control corresponding to when the risk degree R is "2" or less is the collision avoidance control with a risk level LV = 1 associated with the "attention area" in the risk determination area.

[0122] On the other hand, in step S401, when it is determined that the longitudinal collision prediction time TTCz is less than the fourth threshold value Tth4 (step S401: YES), the traveling ECU 14 proceeds to step S403.

[0123] In step S403, the traveling ECU 14 checks whether the longitudinal collision prediction time TTCz is less than a preset fifth threshold value Tth5 (where Tth1 ≤ Tth5 < Tth4).

[0124] And in step S403, when it is determined that the longitudinal collision prediction time TTCz is greater than or equal to the fifth threshold value Tth5 (step S403: NO), the traveling ECU 14 proceeds to step S404.

[0125] In step S404, the traveling_ECU 14 permits preliminary collision avoidance control corresponding to the risk level R being equal to or less than "4", and then exits the subroutine. As a result, even if the current risk level R is, for example, "9", the traveling_ECU 14 permits preliminary collision avoidance control up to the risk level R being equal to "4". Furthermore, when the current risk level R is, for example, "4", the traveling_ECU 14 permits preliminary collision avoidance control corresponding to the risk level R being equal to "4". Note that in this embodiment, the preliminary collision avoidance control corresponding to the risk level R being greater than "2" and equal to or less than "4" is collision avoidance control at risk level LV=2 associated with the "warning zone" in the risk determination zone.

[0126] On the other hand, if it is determined in step S403 that the longitudinal collision prediction time TTCz is smaller than the fifth threshold value Tth5 (step S403: YES), the traveling_ECU 14 proceeds to step S405.

[0127] In step S405, the traveling_ECU 14 permits preliminary collision avoidance control corresponding to the risk level R being equal to or less than "9", and then exits the subroutine. As a result, the traveling_ECU 14 permits preliminary collision avoidance control corresponding to all risk levels R, for example. That is, for example, if the current risk level R is "9", the traveling_ECU 14 permits preliminary collision avoidance control corresponding to the risk level R being "9". Furthermore, for example, if the current risk level R is "4", the traveling_ECU 14 permits preliminary collision avoidance control corresponding to the risk level R being "4". Note that in this embodiment, the preliminary collision avoidance control corresponding to the risk level R being greater than "4" and equal to or less than "9" is collision avoidance control at risk level LV=3, which is associated with the "dangerous area" in the risk determination area.

[0128] 7, when the process proceeds from step S105 to step S106, the travel_ECU 14 makes a forced control intervention determination for the oncoming moving object O. This forced control intervention is a determination to forcibly execute pre-collision avoidance control at risk level LV=3 in an emergency such as when the oncoming moving object O continues to head directly toward the host vehicle M.

[0129] This forced control intervention determination is executed, for example, according to a forced control intervention determination subroutine shown in FIG.

[0130] When the subroutine starts, in step S501, the travel_ECU 14 checks whether or not the state in which the oncoming moving object O is heading directly toward the host vehicle M has continued for a set time (for example, a predetermined number of frames).

[0131] Then, in step S501, if it is determined that the oncoming moving object O is not coming directly toward the host vehicle M (step S501: NO), the travel_ECU 14 exits the subroutine.

[0132] On the other hand, in step S501, if it is determined that the oncoming moving object O is moving directly toward the host vehicle M (step S501: YES), the travel_ECU 14 proceeds to step S502.

[0133] In step S502, the travel_ECU 14 corrects the risk level R for the oncoming moving object O to "9", and corrects the risk level LV permissible for the oncoming moving object O to "3", for example, and then exits the subroutine.

[0134] 7, when the process proceeds from step S106 to step S107, the travel_ECU 14 determines what kind of preparatory collision avoidance action should be taken with respect to the oncoming moving object O. This preparatory collision avoidance action is determined based on, for example, the risk level LV currently allowed for the oncoming moving object O and the current risk level R currently set for the oncoming moving object O.

[0135] Here, for example, as shown in FIG. 15, if the current risk level R for the oncoming moving body O is "0", "0" is set as the risk level for the oncoming moving body O. When the risk level LV=0, the traveling_ECU 14 prohibits the output of an alarm or the like to notify the driver of the presence of the oncoming moving body O. Also, when the risk level LV=0, the traveling_ECU 14 prohibits avoidance control in the longitudinal direction (the front-to-rear direction of the host vehicle M) for the oncoming moving body O. Furthermore, when the risk level LV=0, the traveling_ECU 14 prohibits avoidance control in the lateral direction (the vehicle width direction of the host vehicle M) for the oncoming moving body O.

[0136] Also, for example, as shown in Figure 15, when the risk level R is greater than "0" and control up to risk level LV=1 is permitted for the oncoming moving body O, the driving_ECU14 prohibits the output of an alarm or the like to notify the driver of the presence of the oncoming moving body O.

[0137] Furthermore, when the risk level R is greater than "0" and control up to the risk level LV=1 is permitted for the oncoming moving object O, the travel_ECU 14 permits, for example, first acceleration suppression control instead of brake control as longitudinal direction (front-rear direction of the host vehicle M) avoidance control for the oncoming moving object O. In this first acceleration suppression control, for example, the first acceleration suppression amount is appropriately set only when the host vehicle M is accelerating (including when it is about to accelerate). The first acceleration suppression amount is set, for example, based on a preset map or the like, so that it increases as the longitudinal collision prediction time TTCz decreases.

[0138] Furthermore, when the risk level R is greater than "0" and control up to the risk level LV=1 is permitted for the oncoming moving object O, the travel_ECU 14 permits, for example, steering control within a range in which the host vehicle M does not deviate from the driving lane in which the host vehicle M is traveling, as lateral (vehicle width direction) avoidance control for the oncoming moving object O. In this steering control, the avoidance amount by steering is appropriately set. For example, the avoidance amount is set to increase as the lateral collision prediction time TTCx decreases, based on a preset map or the like. Note that it is desirable to limit the steering wheel speed permitted for this steering control to, for example, approximately 10 deg / s.

[0139] Also, for example, as shown in Figure 15, if the risk level R is greater than "2" and control up to risk level LV=2 is permitted for the oncoming moving body O, the travel_ECU14 sets an alarm or the like to notify the driver of the presence of the oncoming moving body O.

[0140] Furthermore, when the risk level R is greater than "2" and control up to risk level LV=2 is permitted for the oncoming moving object O, the travel_ECU 14 permits second acceleration suppression control instead of brake control as longitudinal avoidance control for the oncoming moving object O. In this second acceleration suppression control, for example, the second acceleration suppression amount is appropriately set only when the host vehicle M is accelerating (including when it is about to accelerate). The second acceleration suppression amount is set, for example, based on a preset map or the like, so that it increases as the longitudinal collision prediction time TTCz decreases. Note that the second acceleration suppression amount is set greater than the first acceleration suppression amount. For example, the second acceleration suppression amount is set with an upper limit set to the deceleration (suppression amount) obtained when the driver releases the accelerator.

[0141] Furthermore, when the risk level R is greater than "2" and control up to risk level LV=2 is permitted for the oncoming moving object O, the travel_ECU 14 permits, for example, steering control to a position where the host vehicle M straddles a lane marking as lateral avoidance control for the oncoming moving object O. In this steering control, the avoidance amount by steering is appropriately set. For example, the avoidance amount is set based on a preset map or the like so that it increases as the lateral collision prediction time TTCx decreases. Note that it is desirable to limit the steering wheel speed permitted for this steering control to, for example, about 80 deg / s.

[0142] Also, for example, as shown in Figure 15, if the risk level R is greater than "4" and control up to risk level LV=3 is permitted for the oncoming moving body O, the driving_ECU14 sets an alarm or the like to notify the driver of the presence of the oncoming moving body O.

[0143] Furthermore, when the risk level R is greater than "4" and control up to a risk level LV=3 is permitted for the oncoming moving object O, the travel_ECU 14 permits braking control as longitudinal avoidance control for the oncoming moving object O. In this braking control, for example, a braking amount is set appropriately. The braking amount is set based on a preset map or the like so that it increases as the collision prediction time TTCz decreases. Note that it is desirable to set this braking amount, for example, with the first target deceleration a1 (for example, 0.4 G) in the above-mentioned emergency collision avoidance control as a limit.

[0144] Furthermore, when the risk level R is greater than "4" and control up to a risk level LV=3 is permitted for the oncoming moving object O, the travel_ECU 14 permits, for example, steering control to a position where the host vehicle M crosses a lane marking as lateral avoidance control for the oncoming moving object O. In this steering control, for example, an avoidance amount by steering is appropriately set. The avoidance amount is set, for example, based on a preset map or the like, so that it increases as the lateral collision prediction time TTCx decreases. Note that it is desirable to limit the steering wheel speed permitted for this steering control to, for example, approximately 240 deg / s.

[0145] When the process proceeds from step S107 to step S108, the travel_ECU 14 checks whether or not control intervention is necessary for the oncoming moving object O, that is, whether or not a predetermined control amount has been set in the above-mentioned step S107.

[0146] Then, in step S108, if it is determined that control intervention is not necessary (step S108: NO), the traveling_ECU 14 exits the routine as is.

[0147] On the other hand, if it is determined in step S108 that control intervention is necessary (step S108: YES), the traveling_ECU 14 proceeds to step S109.

[0148] In step S109, the travel_ECU 14 checks whether the oncoming moving object O has entered the target travel area Am of the host vehicle M or not.

[0149] Then, in step S109, when it is determined that the oncoming moving object O is outside the target traveling area Am of the host vehicle M (step S109: NO), the traveling_ECU 14 proceeds to step S110.

[0150] In step S110, the traveling_ECU 14 executes the preliminary collision avoidance control and then exits the routine. That is, the traveling_ECU 14 executes the preliminary collision avoidance control based on the control amount set in step S107.

[0151] On the other hand, if it is determined in step S109 that the oncoming moving object O is present within the target traveling area Am of the host vehicle M (step S109: YES), the traveling_ECU 14 proceeds to step S111.

[0152] In step S111, the travel_ECU 14 shifts the control for the oncoming moving object O from preliminary collision avoidance control to emergency collision avoidance control, and then exits the routine.

[0153] According to this embodiment, the traveling_ECU 14 recognizes the oncoming moving object O based on the traveling environment information. The traveling_ECU 14 also acquires the distribution characteristics of the lateral positions x associated with the movement of the oncoming moving object O. The traveling_ECU 14 also variably sets a risk determination area for calculating a smaller risk level R as the distance from the center of the oncoming lane toward the outside in the width direction of the oncoming moving object O increases, so that a relatively larger risk level R is calculated as the distribution characteristics of the lateral positions x tend to be more dispersed. The traveling_ECU 14 also calculates the risk level R for the oncoming moving object O according to the overlap state between the target traveling path Rm of the host vehicle M and the risk determination area. The traveling_ECU 14 then recognizes the oncoming moving object O as an obstacle according to the risk level R, and performs pre-collision avoidance control prior to emergency collision avoidance control for the oncoming moving object O recognized as an obstacle.

[0154] This ensures sufficient safety even when an oncoming moving object O, such as an oncoming vehicle, suddenly enters the driving lane of the host vehicle M. That is, the travel_ECU 14 performs preliminary collision avoidance control on the oncoming moving object O according to the risk level R before the oncoming moving object O enters the target driving area Am of the host vehicle M. Therefore, even when the oncoming moving object O crosses a lane marking and suddenly enters ahead of the host vehicle M, emergency collision avoidance control can be performed with ample time to spare.

[0155] In this case, the travel_ECU 14 acquires the distribution characteristics of the lateral positions x accompanying the movement of the oncoming moving object O, and variably sets the risk determination area so that the more dispersed the distribution characteristics of the lateral positions x, the larger the calculated risk level R. This makes it possible to calculate a stable risk level R even when the oncoming moving object O meanders due to swaying or the like, causing the relationship between the risk determination area and the target traveling path Rm of the host vehicle M to fluctuate. Therefore, it is possible to accurately determine the risk due to swaying or the like of the oncoming moving object O, and to realize appropriate pre-collision avoidance control.

[0156] Furthermore, the travel_ECU 14 sets the lateral position x relative to the host vehicle M when the oncoming moving object O is first detected as a reference lateral position x0, and generates a histogram in which the change Δx in the lateral position x of the oncoming moving object O relative to the reference lateral position x0 is aggregated into classes for each predetermined change Δx as a distribution characteristic of the lateral position x. This makes it possible to easily determine the sway of the oncoming moving object O.

[0157] Furthermore, the traveling_ECU 14 variably sets the risk determination region so that the calculated risk level becomes relatively larger as the distribution width Wx of the lateral position x in the distribution characteristics of the lateral position x becomes wider. This makes it possible to realize appropriate pre-collision avoidance control in accordance with the swaying state of the oncoming moving object O.

[0158] Furthermore, the travel_ECU 14 varies the control level (risk level) allowed for the preliminary collision avoidance control depending on the value of the longitudinal collision prediction time TTCz, thereby making it possible to realize appropriate preliminary collision avoidance control for the oncoming moving object O.

[0159] In the above-described embodiment, the image recognition_ECU 13, the driving_ECU 14, the CP_ECU 21, the E / G_ECU 22, the T / M_ECU 23, the BK_ECU 24, and the PS_ECU 25 are configured by well-known microcomputers including a CPU, RAM, ROM, a nonvolatile storage unit, and peripheral devices. The ROM stores programs to be executed by the CPU and fixed data such as data tables in advance. Note that all or part of the functions of the processor may be configured by logic circuits or analog circuits. Furthermore, the processing of various programs may be implemented by electronic circuits such as FPGAs.

[0160] The invention described in the above embodiments is not limited to these embodiments, and various modifications can be made in the implementation stage without departing from the gist of the invention. Furthermore, the above embodiments include inventions at various stages, and various inventions can be extracted by appropriate combinations of the disclosed multiple constituent elements.

[0161] For example, if some of the constituent elements are deleted from all the constituent elements shown in the above-mentioned form, and the stated problem can still be solved and the stated effect can still be obtained, then the configuration from which these constituent elements have been deleted can be extracted as an invention.

[0162] For example, instead of the cumulatively calculated risk level R, it is also possible to perform preliminary collision avoidance control by using the risk level R calculated directly from the risk determination area. [Explanation of symbols]

[0163] 1. Driving assistance devices 10...Camera unit 11...Stereo camera 11a ... Main camera 11b ... Sub camera 12 … IPU 13...Image Recognition_ECU 14 … Driving_ECU 21 … CP_ECU 22 ... E / G_ECU 23 ... Transmission ECU 24 … BK_ECU 25 … PS_ECU 31...HMI 32 ... Throttle actuator 33... Hydraulic control circuit 34... Brake actuator 35... Electric power steering motor 36 ... Locator unit 36a … GNSS sensor 36b ... Road map DB 37lf ... Left front side sensor 37lr ... Left rear side sensor 37rf ... Right front side sensor 37rr ... Right rear side sensor M... Vehicle (own vehicle) O … Oncoming moving object

Claims

1. a driving environment recognition unit that recognizes driving environment information outside the vehicle; an obstacle recognition unit that recognizes obstacles present on a target travel path of the host vehicle based on the driving environment information; an emergency collision avoidance control unit that performs emergency collision avoidance control to avoid a collision with the obstacle when it is determined that a collision prediction time between the host vehicle and the obstacle is smaller than a preset threshold and that there is a high possibility that the host vehicle will collide with the obstacle; an oncoming moving object recognition unit that recognizes an oncoming moving object moving on an oncoming lane adjacent to the lane in which the host vehicle is traveling, with a speed component in a direction opposite to the traveling direction of the host vehicle, based on the traveling environment information; a lateral position distribution characteristic acquisition unit that acquires a distribution characteristic of the lateral position of the opposing moving object that accompanies the movement of the opposing moving object by setting the lateral position of the opposing moving object relative to the host vehicle when the opposing moving object is first detected as a reference lateral position, calculating the amount of change in the lateral position relative to the reference lateral position at each set period, and using the amount of change in the lateral position; a risk determination area setting unit that sets a region surrounded by a lane width direction set by the lane width between the driving lane and the oncoming lane and a lane direction set from when the oncoming moving object is first detected until the oncoming moving object approaches the vehicle as a risk determination area, and calculates a lower risk level in the risk determination area as the distance from the center of the oncoming lane toward both outer sides in the road width direction increases based on the distribution characteristics of the lateral position; a risk level calculation unit that calculates the risk level set in the risk determination area through which the target travel path of the host vehicle passes as a risk level of the oncoming moving object to the host vehicle; a preliminary collision avoidance control unit that recognizes the oncoming moving object as the obstacle according to the risk level of the oncoming moving object to the host vehicle, and performs preliminary collision avoidance control prior to the emergency collision avoidance control for the oncoming moving object recognized as the obstacle, A vehicle driving assistance device characterized in that the risk judgment area setting unit calculates a higher risk level as the sway width of the oncoming moving body becomes larger and the distribution characteristics of the lateral position tend to be more dispersed.

2. The vehicle driving assistance device according to claim 1, characterized in that the lateral position distribution characteristic acquisition unit generates a histogram as the distribution characteristic of the lateral position, in which the amount of change in the lateral position of the oncoming moving body relative to the reference lateral position is aggregated into classes for each predetermined amount of change.

3. 3. The vehicle driving assistance device according to claim 1, wherein the risk determination region setting unit increases the risk level as the distribution width of the lateral position in the distribution characteristics becomes wider.

4. 4. The vehicle driving assistance device according to claim 1, wherein the risk level calculation unit performs upper limit processing on the risk level, with a preset value as the upper limit.

5. 5. The vehicle driving assistance device according to claim 1, wherein the pre-collision avoidance control unit increases the risk of permitting the pre-collision avoidance control as the collision prediction time in the longitudinal direction of the host vehicle, calculated based on the relative distance and relative speed in the longitudinal direction between the host vehicle and the oncoming moving object, becomes shorter.

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