Vehicle driving assistance device and vehicle driving assistance system

Abstract

To provide a drive support system of a vehicle which can sufficiently secure safety even if an on-coming vehicle or the like abruptly intrudes into a traveling lane of an own vehicle.SOLUTION: A traveling_ECU 14o of an on-coming moving body O calculates a risk degree R exerted on a peripheral vehicle by the on-coming moving body O on the basis of at least either a history of a behavior of the on-coming moving body O with respect to a partitioning line for partitioning an on-coming lane, or a behavior of a driver who drives the on-coming moving body O, and emits light having a light emission pattern which is preset according to the risk degree R toward a periphery from a light source unit 38. On the other hand, a traveling_ECU 14m of an own vehicle M acquires the risk degree R of the on-coming moving body O on the basis of the light emission pattern of the light source unit 38. Also, the traveling_ECU 14m recognizes the on-coming moving body O as an obstacle according to the risk degree R, and performs preliminary collision avoidance control prior to emergency collision avoidance control to the on-coming moving body O which is recognized as the obstacle.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a vehicle driving assistance device and a vehicle driving assistance system that are equipped with 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] The present invention aims to provide a vehicle driving assistance device that can ensure sufficient safety even when an oncoming vehicle or the like suddenly enters the driving lane of the vehicle, and a vehicle driving assistance device. [Means for solving the problem]

[0009] Book According to one aspect of the present invention, a driving assistance device for a vehicle includes: a risk level calculation unit that calculates a risk level that a host vehicle poses to surrounding vehicles based on at least one of a history of behavior of the host vehicle relative to a lane marking that defines a lane in which the host vehicle is traveling and a behavior of a driver of the host vehicle; and a light source unit that emits light in a predetermined light emission pattern toward the periphery of the host vehicle in accordance with the risk level. The risk level calculation unit calculates the distances from the left and right lane markings that define the driving lane for each predetermined section to the side edges of the vehicle as lateral positions relative to the left and right lane markings, calculates intermediate risk levels for the vehicle based on a history of the lateral positions relative to the lane markings, and calculates the sum of the intermediate risk levels as the risk level. .

[0010] a risk level calculation unit that calculates a risk level of a host vehicle to nearby vehicles based on at least one of a history of behavior of the host vehicle relative to a dividing line that divides the host vehicle's travel lane and behavior of a driver driving the host vehicle; a light source unit that emits light with a preset emission pattern according to the risk level toward the periphery of the host vehicle; a risk level acquisition unit that acquires, with respect to an oncoming moving object that is traveling on an oncoming lane adjacent to the host vehicle's travel lane and has a speed component in a direction opposite to a traveling direction of the host vehicle, a risk level calculated for the oncoming moving object based on the emission pattern of the light source unit provided on the oncoming moving object; an emergency collision avoidance control unit that performs emergency collision avoidance control to avoid collision with the obstacle when it is determined that there is a high possibility that the host vehicle will collide with the obstacle; and a pre-collision avoidance control unit that recognizes the oncoming moving object as the obstacle according to the risk level of the oncoming moving object, and performs pre-collision avoidance control for the oncoming moving object recognized as the obstacle prior to the emergency collision avoidance control. The risk level calculation unit calculates the distances from the left and right lane markings that define the driving lane for each predetermined section to the side edges of the vehicle as lateral positions relative to the left and right lane markings, calculates intermediate risk levels for the vehicle based on a history of the lateral positions relative to the lane markings, and calculates the sum of the intermediate risk levels as the risk level. .

[0011] A driving assistance system for a vehicle according to one aspect of the present invention includes a risk level calculation unit that is mounted on an oncoming moving object that moves on an oncoming lane adjacent to the driving lane of the vehicle with a speed component in the opposite direction to the traveling direction of the vehicle, and calculates a risk level that the oncoming moving object poses to surrounding vehicles based on at least one of a history of behavior of the oncoming moving object with respect to a dividing line that divides the oncoming lane and the behavior of a driver driving the oncoming moving object; and a risk level calculation unit that is mounted on the oncoming moving object and emits light in a predetermined illumination pattern according to the risk level toward the periphery of the oncoming moving object. a risk level acquisition unit mounted on the host vehicle and configured to acquire the risk level of the oncoming moving object based on a light emission pattern of the light source unit; an emergency collision avoidance control unit mounted on the host vehicle and configured to, when it is determined that the host vehicle is highly likely to collide with an obstacle, perform emergency collision avoidance control to avoid collision with the obstacle; and a preliminary collision avoidance control unit mounted on the host vehicle and configured to recognize the oncoming moving object as the obstacle according to the risk level, and perform preliminary collision avoidance control for the oncoming moving object recognized as the obstacle prior to the emergency collision avoidance control. The risk level calculation unit calculates the distances from the left and right lane markings that define the driving lane for each predetermined section to the side edges of the vehicle as the left and right lane marking lateral positions, calculates intermediate risk levels for the oncoming moving object based on a history of the lane marking lateral positions, and calculates the sum of the intermediate risk levels as the risk level. . [Effects of the Invention]

[0012] According to 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]

[0013] [Figure 1] Schematic diagram of the driving assistance system [Figure 2] Schematic diagram of the driving assistance device [Figure 3] FIG. 1 is an explanatory diagram showing the monitoring areas of a stereo camera and a radar; [Figure 4] Schematic diagram of the light source unit installed in the vehicle [Figure 5] FIG. 10 is an explanatory diagram showing an obstacle present ahead of the target travel path of the host vehicle. [Figure 6] An explanatory diagram showing an oncoming moving object in an oncoming lane [Figure 7]An explanatory diagram showing the lateral position of the vehicle relative to the lane markings. [Figure 8] An explanatory diagram showing the behavior pattern of the host vehicle. [Figure 9] An explanatory diagram showing the behavior pattern of the host vehicle. [Figure 10] An explanatory diagram showing the behavior pattern of the host vehicle. [Figure 11] An explanatory diagram showing a risk assessment map [Figure 12] Flowchart showing a risk level calculation routine [Figure 13] Flowchart showing a preliminary collision avoidance control routine [Figure 14] Flowchart showing the risk level upper limit processing subroutine [Figure 15] Flowchart showing a risk level reduction processing subroutine [Figure 16] Flowchart showing forced control intervention determination subroutine [Figure 17] An explanatory diagram illustrating a case where the risk level of an oncoming vehicle increases due to factors other than swaying. [Figure 18] An explanatory diagram illustrating a case where the risk level of an oncoming moving object increases due to factors other than sway. [Figure 19] An explanatory diagram illustrating a case where the risk level of an oncoming vehicle increases due to factors other than swaying. [Figure 20] FIG. 10 is an explanatory diagram illustrating the control content of preliminary collision avoidance control. DETAILED DESCRIPTION OF THE INVENTION

[0014] 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.

[0015] As shown in FIG. 1, a driving assistance system 100 of this embodiment includes a host vehicle M and an oncoming vehicle (oncoming moving object O) as a plurality of vehicles capable of wirelessly communicating with each other.

[0016] The host vehicle M and the oncoming moving object O are each equipped with a driving assistance device 1.

[0017] Next, the configuration of the driving assistance device 1 mounted on the host vehicle M will be described with reference to Figures 2 and 3. The driving assistance device 1 is configured to have, for example, a camera unit 10 fixed to the center of the front and upper part of the cabin of the vehicle (host vehicle) M.

[0018] 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.

[0019] 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.

[0020] The main camera 11a and the sub-camera 11b capture stereo images of the driving environment in the area Af (see FIG. 3) outside the vehicle from different viewpoints. The imaging cycles of the main camera 11a and the sub-camera 11b are synchronized with each other.

[0021] 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.

[0022] 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 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 or the like on the sequence of extracted marking line candidate points. This allows the image recognition_ECU 13 to calculate the curvature of the left and right marking lines for each predetermined section. Furthermore, the image recognition_ECU 13 calculates the lane width from the difference between the curvatures of the left and right lane markings.

[0023] 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.

[0024] 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.

[0025] The various pieces of information recognized by the image recognition_ECU 13 are output to the traveling_ECU 14 as traveling environment information.

[0026] Furthermore, when the recognized three-dimensional object is a moving body such as a vehicle equipped with a light-emitting unit 38 (described later), the image recognition_ECU 13 recognizes the light emission pattern of the light emitted from the light-emitting unit 38. This light emission pattern includes, for example, the light emission timing, the light emission color, the arrangement of each light emission color, and the light emission sequence of each light emission color.

[0027] 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, and a light emission pattern recognition unit that recognizes the light emission pattern of a specific part of the moving body.

[0028] The traveling_ECU 14 is a control unit for controlling the driving assistance device 1 in an integrated manner.

[0029] 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).

[0030] In addition, 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.

[0031] Furthermore, the travel_ECU 14 is connected to a light source unit 38 for transmitting information to other vehicles around the host vehicle M by using a light emission pattern.

[0032] 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.

[0033] 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 using the HMI 31.

[0034] 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 via the HMI 31, the set vehicle speed (set vehicle speed) Vs for the vehicle M, and the operation status of the turn signal switch.

[0035] Furthermore, the CP_ECU 21 estimates the driver's wakefulness state based on the change in the driver's line of sight detected by the DMS, etc. Then, the CP_ECU 21 outputs the estimated driver's wakefulness state to the driving_ECU 14.

[0036] 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).

[0037] 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.

[0038] 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.

[0039] 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.

[0040] 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.

[0041] 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.

[0042] 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.

[0043] The locator unit 36 ​​includes a GNSS sensor 36a and a high-precision road map database (road map DB) 36b.

[0044] 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.

[0045] 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.

[0046] 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.

[0047] 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. 3) 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.

[0048] 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. 3) 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.

[0049] 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.

[0050] 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.

[0051] 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 3) with the center of the vehicle M as the origin, for example.

[0052] The light source unit 38 is provided at a specific location of the host vehicle M. This specific location is set to, for example, at least one of the four corners of the host vehicle M (the left and right sides of the front bumper, the left and right sides of the rear bumper, etc.), the rear of the host vehicle M, and the roof of the host vehicle M. Note that FIG. 4 illustrates an example of a configuration in which the light source unit 38 is provided at the left and right sides of the front bumper.

[0053] The light source unit 38 has, for example, a plurality of (e.g., three) light-emitting diodes (LEDs) 38a, 38b, and 38c that emit light of different colors as light sources. Each of these LEDs 38a to 38c can emit light according to a preset light-emitting pattern (light-emitting timing, light-emitting color, arrangement of each light-emitting color, light-emitting sequence of each light-emitting color, etc.).

[0054] In this embodiment, a plurality of light emission patterns are set for the light source unit 38. Each light emission pattern is standardized in association with a risk level R of the host vehicle M, which will be described later.

[0055] The light source unit 38 may be configured to include, for example, a single light source, or may be configured to be capable of displaying characters, symbols, etc. using a plurality of light sources arranged in a matrix.

[0056] 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.

[0057] 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.

[0058] 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 semi-automated driving mode in which the host vehicle M is driven while reflecting the driver's driving operation. 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 (ALKC), active lane keep bouncing (ALKA), 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.

[0059] 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.

[0060] 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.

[0061] 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.

[0062] 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.

[0063] 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.

[0064] 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.

[0065] 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).

[0066] 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, autonomous emergency braking (AEB) and autonomous emergency steering (AES).

[0067] Emergency brake control is basically a control for avoiding a collision with an obstacle present ahead of the host vehicle M on the target travel path Rm by braking. During emergency brake control, the travel_ECU 14 sets a target travel area Am ahead of the host vehicle M, for example, as shown in FIG. 5. This target travel area Am has a predetermined width (for example, equal to or greater than the vehicle width of the host vehicle M) centered on the target travel path Rm. The travel_ECU 14 also detects obstacles such as a preceding vehicle or a stopped vehicle present in the target travel area Am based on the travel environment information. Furthermore, the travel_ECU 14 calculates a collision prediction time (longitudinal collision prediction time) TTCz in the longitudinal direction of the host vehicle M as a collision prediction time with the obstacle. This longitudinal collision prediction time TTCz is calculated based on the relative speed and relative distance between the host vehicle M and the obstacle.

[0068] Then, when the longitudinal collision prediction time TTCz becomes smaller than a preset first threshold value Tth1, the traveling_ECU 14 executes the primary brake control. When the primary brake control is started, the traveling_ECU 14 decelerates the host vehicle M using a preset first target deceleration a1 (e.g., 0.4 G).

[0069] Furthermore, when the longitudinal collision prediction time TTCz becomes smaller than a second threshold value Tth2 (where Tth2 < Tth1) set in advance, the traveling ECU 14 executes secondary braking control. When the secondary braking control is started, the traveling ECU 14 decelerates the host vehicle M using a second target deceleration a2 (for example, 1G) set in advance until the relative speed with the obstacle becomes "0".

[0070] The emergency steering control is a control for avoiding a collision with an obstacle existing ahead on the target traveling path of the host vehicle M by steering. When it is determined that the traveling ECU 14 cannot avoid a collision with an obstacle by, for example, the secondary braking control, the traveling ECU 14 executes the emergency steering control instead of or in combination with the emergency braking control.

[0071] 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 the emergency steering control (for example, refer to the host vehicle M' in FIG. 5).

[0072] During this emergency steering control, the traveling ECU 14 sets a target lateral position to the side of the obstacle. Further, the traveling ECU 14 sets a new target traveling path Ravo until the host vehicle M reaches the target lateral position. This new target traveling path Ravo is set by dividing it, for example, into an additional 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 traveling path. Then, the traveling ECU 14 executes steering control along the new target traveling path Ravo.

[0073] Note that the traveling ECU 14 can also variably set the first to third threshold values Tth1 to Tth3 according to the wrap rate of the obstacle in the vehicle width direction 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 traveling area Am. Then, the traveling ECU 14 sets the first to third threshold values Tth1 to Tth3 to increase as the wrap rate Rr increases using, for example, a preset map or the like.

[0074] Incidentally, when the host vehicle M is traveling on a road without a central divider, a case is assumed in which an oncoming moving object O present in the oncoming lane suddenly intrudes into the traveling lane of the host vehicle M. Here, in this embodiment, the oncoming moving object O refers to an oncoming vehicle (including a two-wheeled vehicle) or the like that is traveling with a velocity component in the opposite direction to the traveling direction of the host vehicle M. In order to realize collision avoidance with such an oncoming moving object O, the travel_ECU 14 of this embodiment extends and applies emergency collision avoidance control to an oncoming moving object O that intrudes into the traveling lane of the host vehicle M from the oncoming lane of a road without a central divider.

[0075] 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.

[0076] In order to execute preliminary collision avoidance control, the travel_ECU 14 acquires information on various moving bodies such as other vehicles present around the host vehicle M via the stereo camera 11. That is, the travel_ECU 14 acquires information on other vehicles such as the positions of other vehicles in real space, the moving speeds of other vehicles, the moving directions of other vehicles, etc. from the traveling environment information, and, if a light source unit 38 is provided on the other vehicles, etc., acquires a risk level R when the other vehicles, etc. are traveling based on the light emission pattern of the light source unit 38.

[0077] Furthermore, the traveling_ECU 14 calculates the risk level R of the host vehicle M as information to be notified to other vehicles and the like present around the host vehicle M. That is, the traveling_ECU 14 calculates the distance from the left and right lane markings that define the driving lane in which the host vehicle M is traveling to the host vehicle M (for example, the distance from the left and right lane markings to the left and right side edges of the host vehicle M) as the left and right lane marking lateral positions. The calculation of the lane marking lateral positions is performed, for example, based on driving environment information. The lane marking lateral positions are also calculated at predetermined calculation intervals. The traveling_ECU 14 then calculates the risk level R based on the history of the lane marking lateral positions calculated at set intervals within a predetermined time period.

[0078] Specifically, the traveling_ECU 14 calculates the distances from the left and right lane markings that define the lane in which the vehicle M is traveling to the vehicle M as the left and right lane marking lateral positions a and b (see FIG. 7).The traveling_ECU 14 then stores the calculated left and right lane marking lateral positions a and b as history for a preset time period of 3T (seconds).

[0079] The travel_ECU 14 also calculates a risk level intermediate value for the oncoming moving object O based on the history of the left and right lateral positions a, b relative to the lane marking for each predetermined section.

[0080] In this embodiment, the risk level intermediate value is calculated based on the history of the left and right lateral positions a and b relative to the lane marking each time the oncoming moving object O moves for T seconds, for example.

[0081] When calculating this intermediate risk level value, the travel_ECU 14 calculates the average value a_ave of the lateral position a relative to the left lane marking and the average value b_ave of the lateral position b relative to the right lane marking for each of the past T seconds.

[0082] The traveling_ECU 14 also calculates the difference Δx (= a_ave - b_ave) between the average values ​​of the lateral positions of the left and right lane markings for each of the past T seconds. Based on this, the traveling_ECU 14 determines the moving direction of the oncoming moving object O in the road width direction for each of the past T seconds. That is, for example, when the difference Δx between the average values ​​is a negative value, the traveling_ECU 14 determines that the moving direction of the host vehicle M is to the left. On the other hand, for example, when the difference Δx between the average values ​​is a positive value, the traveling_ECU 14 determines that the moving direction of the host vehicle M is to the right.

[0083] Then, when the absolute value |Δx| (=|a_ave-b_ave|) of the difference between the average values ​​is greater than a preset threshold value Δxth, the traveling_ECU 14 determines that the host vehicle M is moving in the above-mentioned determination direction. On the other hand, when the absolute value |Δx| (=|a_ave-b_ave|) of the difference between the average values ​​is equal to or less than a preset threshold value Δxth, the traveling_ECU 14 determines that the host vehicle M is not moving in the road width direction.

[0084] As a result, the traveling_ECU14 sequentially recognizes the direction of movement of the host vehicle M from the past 3T seconds to the past 2T seconds (timing t-2), the direction of movement of the host vehicle M from the past 2T seconds to the past T seconds (timing t-1), and the direction of movement of the host vehicle M from the past T seconds to the present (timing t).

[0085] The combination of the behavior of the host vehicle M at these timings t-2, t-1, and t is classified into, for example, one of 27 patterns shown in Figures 8 to 10. The traveling_ECU 14 calculates the risk level intermediate values ​​Rt-2, Rt-1, and Rt at each timing based on the classified behavior patterns of the host vehicle M. These risk level intermediate values ​​Rt-2, Rt-1, and Rt can be calculated, for example, by referring to the map shown in Figure 11. Then, the traveling_ECU 14 calculates the final risk level R for the host vehicle M by adding up the calculated risk level intermediate values ​​Rt-2, Rt-1, and Rt.

[0086] Furthermore, the traveling_ECU 14 can also correct the risk level R calculated based on the history of the lateral position relative to the lane marking, based on various behaviors of the driver.

[0087] For example, when the driving_ECU 14 receives information about the driver's state of alertness from the CP_ECU 21, the driving_ECU 14 calculates a risk level R1 corresponding to the state of alertness based on a preset map or the like.

[0088] Furthermore, when information relating to a sudden accelerator operation by the driver is input from the E / G_ECU 22, the travel_ECU 14 calculates a risk level R2 corresponding to the accelerator operation based on a preset map or the like.

[0089] Furthermore, when information relating to a sudden braking operation by the driver is input from the BK_ECU 24, the travel_ECU 14 calculates a risk level R3 corresponding to the braking operation based on a preset map or the like.

[0090] Furthermore, when information relating to abrupt steering by the driver is input from the PS_ECU 25, the travel_ECU 14 calculates a risk level R4 corresponding to the steering based on a preset map or the like.

[0091] Furthermore, when the driving_ECU 14 detects an abnormal operation by the driver that ignores traffic rules (such as ignoring a traffic light) based on driving environment information and road map information from the locator unit 36, it calculates a risk level R5 corresponding to the abnormal operation based on a pre-set map, etc.

[0092] When these risk levels R1 to R5 are calculated, the travel_ECU 14 appropriately corrects the risk level R calculated based on the history of the lateral position relative to the lane marking using the risk levels R1 to R5.

[0093] Of course, the driver's behavior used to calculate the risk level is not limited to the above-mentioned behavior. Furthermore, the traveling_ECU 14 can appropriately calculate the risk level R by directly using one or more of the risk levels R1 to R5 based on various driver behaviors, instead of the risk level R based on the history of the lateral position relative to the lane marking. In other words, the traveling_ECU 14 calculates the risk level R that the host vehicle M poses to surrounding vehicles based on at least one of the history of the host vehicle M's behavior relative to the lane marking or the behavior of the driver driving the host vehicle M.

[0094] Then, the travel_ECU 14 notifies moving objects such as other vehicles present around the host vehicle M of the risk level R of the host vehicle M calculated in this manner via the light source unit 38.

[0095] In this manner, in this embodiment, the travel_ECU 14 is capable of acquiring information such as the risk level R of other vehicles and notifying information such as the risk level R of the host vehicle M to other vehicles.

[0096] In order to execute the preliminary collision avoidance control, the traveling_ECU 14 determines whether or not a median strip exists on the road, separating the traveling lane of the host vehicle M from the oncoming lane, based on the traveling environment information. 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. 6). This detection of the oncoming moving object O is basically performed based on the traveling environment information recognized by the image recognition_ECU 13.

[0097] When an oncoming moving object O is detected, the travel_ECU 14 calculates the longitudinal velocity component Voz and the lateral velocity component Vox corresponding to the longitudinal and lateral directions of the vehicle M based on the moving speed of the oncoming moving object O (hereinafter referred to as speed Vo).

[0098] 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.

[0099] 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.

[0100] 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.

[0101] Furthermore, when the oncoming moving object O is equipped with a light source unit 38, the travel_ECU 14 acquires a risk level R of the oncoming moving object O based on the light emission pattern of the light source unit 38 recognized by the image recognition_ECU 13. That is, the travel_ECU 14 acquires the risk level R of the oncoming moving object O according to the light emission pattern of the light source unit 38 by referring to a map or the like that is set in advance in the travel_ECU 14. Furthermore, the travel_ECU 14 determines whether the oncoming moving object O is an obstacle that may collide with the host vehicle M based on the acquired risk level R. Then, when the oncoming moving object O is recognized as an obstacle, the travel_ECU 14 appropriately executes pre-collision avoidance control for the oncoming moving object O prior to emergency collision avoidance control.

[0102] Here, in this embodiment, the configuration of the driving assistance device 1 mounted on the oncoming moving body O is the same as the configuration of the driving assistance device 1 mounted on the host vehicle M. Therefore, a detailed description of the configuration of the driving assistance device 1 mounted on the oncoming moving body O will be omitted. In the following description, when it is necessary to distinguish between the driving assistance device 1 and each component of the driving assistance device 1 related to the host vehicle M and the driving assistance device 1 and each component of the driving assistance device 1 related to the oncoming moving body O, "m" or "o" will be added to the end of the reference numeral as appropriate.

[0103] As described above, in this embodiment, the traveling_ECU 14 corresponds to a specific example of an emergency collision avoidance control unit, a risk level calculation unit, a risk level acquisition unit, and a preliminary collision avoidance control unit. More specifically, when considering the preliminary collision avoidance control performed by the host vehicle M as a reference, the traveling_ECU 14m corresponds to a specific example of an emergency collision avoidance control unit, a risk level acquisition unit, and a preliminary collision avoidance control unit. On the other hand, the traveling_ECU 14o corresponds to a specific example of a risk level calculation unit.

[0104] Next, prior to a detailed description of the preliminary collision avoidance control, the calculation of the risk level R performed in another vehicle or the like will be described with reference to the flowchart of the risk level calculation routine shown in Fig. 12. Note that this calculation of the risk level R is performed in various moving objects equipped with a driving assistance device 1 having a light-emitting unit 38. Here, the calculation of the risk level R by the travel_ECU 14o of the oncoming moving object O will be described.

[0105] When the routine starts, in step S001, the traveling_ECU 14o calculates the distances from the left and right lane markings that define the oncoming lane to the side edges of the oncoming moving object O as lane marking lateral positions a and b. Then, the traveling_ECU 14o stores the calculated lane marking lateral positions a and b as the movement history of the oncoming moving object O.

[0106] In the following step S002, the travel_ECU 14o clears, from among the stored lane marking lateral positions a and b, lane marking lateral positions a and b that are older than a preset time (past 3T seconds).

[0107] In the following step S003, the travel_ECU 14o reads the movement history of the oncoming moving object O for the past 3T seconds, and calculates the average values ​​a_ave and b_ave of the left and right lateral positions a and b relative to the lane marking for each of the past T seconds.

[0108] In the following step S004, the travel_ECU 14o determines the behavior of the oncoming moving object O at each of the timings t-2, t-1, and t based on the average values ​​a_ave and b_ave of the left and right lane marking lateral positions a and b for each of the past T seconds. That is, the travel_ECU 14o calculates the difference Δx between the average values ​​a_ave and b_ave for each section of the past T seconds, and recognizes the behavior of the oncoming moving object O at each of the timings t-2, t-1, and t based on the positive / negative and absolute value of this difference Δx.

[0109] In the following step S005, the travel_ECU 14o refers to a preset map or the like to sequentially calculate intermediate risk levels Rt-2, Rt-1, and Rt for the oncoming moving object O at each of the timings t-2, t-1, and t.

[0110] Then, in step S006, the travel_ECU 14o calculates the current risk level R for the oncoming moving object O by adding the calculated intermediate risk levels Rt-2, Rt-1, and Rt.

[0111] In the following step S007, the traveling_ECU 14o acquires various behavior information of the driver, such as information on the driver's wakefulness state, accelerator operation by the driver, brake operation by the driver, steering by the driver, and abnormal operation by the driver.

[0112] In the following step S008, the travel_ECU 14o calculates risk levels R1 to R5 based on the acquired various pieces of driver behavior information.

[0113] In the following step S009, the traveling_ECU 14o uses the calculated risk levels R1 to R5 to correct the risk level R. For example, the traveling_ECU 14o adds the calculated risk levels R1 to R5 to the risk level R as appropriate.

[0114] In the following step S010, the traveling_ECU 14o notifies the calculated corrected risk level R via the light-emitting unit 38 to the surrounding area.

[0115] Next, details of the preliminary collision avoidance control for the host vehicle M will be described with reference to a flowchart of a preliminary collision avoidance control routine shown in Fig. 13. This preliminary collision avoidance control routine is repeatedly executed at set time intervals by the travel_ECU 14m when the host vehicle M is traveling on a road without a central reservation.

[0116] When the routine starts, the traveling_ECU 14 checks in step S101 whether or not an oncoming moving object O equipped with a light emitting unit 38 is present on the oncoming lane.

[0117] Then, in step S101, if it is determined that an oncoming moving object O equipped with the light emitting unit 38 does not exist on the oncoming lane (step S101: NO), the traveling_ECU 14m exits the routine.

[0118] On the other hand, in step S101, if it is determined that an oncoming moving object O equipped with the light emitting unit 38 is present on the oncoming lane (step S101: YES), the travel_ECU 14m proceeds to step S102.

[0119] In step S102, the risk level R of the opposing moving object O is obtained based on the light emission pattern of the light emitting unit 38 of the opposing moving object O.

[0120] In the following step S103, the traveling_ECU 14m calculates a predicted longitudinal collision time TTCz and a predicted lateral collision time TTCx with respect to the oncoming moving object O.

[0121] When proceeding from step S103 to step S104, the traveling_ECU 14m 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.

[0122] In this upper limit process, when it is expected that the risk level R will increase due to a factor other than the swaying of the oncoming moving object O, the travel_ECU 14m limits the risk level R to, for example, "4" or less.

[0123] 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.

[0124] When the subroutine starts, the traveling_ECU 14m checks in step S201 whether the oncoming moving object O is moving on a straight road with good visibility.

[0125] Then, in step S201, if it is determined that the oncoming moving object O is not moving on a straight path (step S201: NO), the traveling_ECU 14m exits the subroutine.

[0126] On the other hand, in step S201, if it is determined that the oncoming moving object O is moving on a straight path (step S201: YES), the traveling_ECU 14m proceeds to step S202.

[0127] In step S202, the traveling_ECU 14m acquires the target traveling path Rm set for the host vehicle M.

[0128] In the following step S203, the travel_ECU 14m 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.

[0129] In the following step S204, the traveling_ECU 14m 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. 6), the traveling_ECU 14m 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. 6). Furthermore, assuming that the oncoming moving object O has moved to the predicted collision point Pc, the traveling_ECU 14m calculates the collision angle θc based on the relative angle between the oncoming moving object O' after the movement and the host vehicle M.

[0130] In the following step S205, the travel_ECU 14m checks whether the blinker of the oncoming moving object O is blinking.

[0131] Then, in step S205, if it is determined that the blinker of the oncoming moving object O is blinking (step S205: YES), the traveling_ECU 14m proceeds to step S209.

[0132] In step S209, the traveling_ECU 14m performs upper limit processing to set the risk level R to, for example, "4" or less, and then exits the subroutine.

[0133] That is, for example, as shown in Fig. 17, a case where the risk level R of the oncoming moving object O becomes large due to a factor 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 blinker. 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.

[0134] On the other hand, in step S205, if it is determined that the blinker of the oncoming moving object O is not blinking (step S205: NO), the traveling_ECU 14m proceeds to step S206.

[0135] In step S206, the traveling_ECU 14m 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 14m checks whether the predicted traveling path Ro of the oncoming moving object O calculated in step S203 and the predicted collision point Pc and collision angle θc with the oncoming moving object O calculated in step S204 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_ECU 14m determines that the behavior of the oncoming moving body O has changed to an unfavorable side when at least one of the following occurs: the predicted path of travel Ro tilts toward the vehicle M, the predicted collision point Pc moves toward the vehicle M, or the collision angle θc changes to an increasing side.

[0136] Then, when the traveling_ECU 14m determines that the behavior of the oncoming moving object O has changed to the advantageous side (step S206: YES), the process proceeds to step S209.

[0137] In step S209, the traveling_ECU 14m performs upper limit processing to set the risk level R to "4" or less, for example, and then exits the subroutine.

[0138] On the other hand, if it is determined in step S206 that the behavior of the oncoming moving object O has changed to the unfavorable side (step S206: NO), the traveling_ECU 14m proceeds to step S207.

[0139] In step S207, the travel_ECU 14m checks whether or not a stationary object such as a parked vehicle exists near the oncoming moving object O on the oncoming lane.

[0140] Then, in step S207, if it is determined that a parked vehicle or the like is present on the oncoming lane (step S207: YES), the traveling_ECU 14m proceeds to step S209.

[0141] In step S209, the traveling_ECU 14m performs upper limit processing to set the risk level R to "4" or less, for example, and then exits the subroutine.

[0142] That is, for example, as shown in FIG. 18, 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 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 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 decrease. Therefore, in such a case, it is unlikely 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.

[0143] On the other hand, if it is determined in step S207 that there is no parked vehicle or the like on the oncoming lane (step S207: NO), the traveling_ECU 14m proceeds to step S208.

[0144] In step S208, the traveling_ECU 14m checks whether the oncoming moving object O is merging from a branch road into an oncoming lane.

[0145] Then, in step S208, if it is determined that the oncoming moving object O is merging from a branch road (step S208: YES), the traveling_ECU 14m proceeds to step S209.

[0146] In step S209, the traveling_ECU 14m performs upper limit processing to set the risk level R to "4" or less, for example, and then exits the subroutine.

[0147] That is, for example, as shown in FIG. 19, 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 branch 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 difficult to assume that the oncoming moving object O will suddenly intrude into the driving lane of the host vehicle M at the timing of a collision with the host vehicle M, and therefore the control content is limited by upper limit processing.

[0148] On the other hand, if it is determined in step S208 that the oncoming moving object O is not merging from a branch road (step S208: NO), the traveling_ECU 14m exits the subroutine.

[0149] 13, when the process proceeds from step S104 to step S105, the traveling_ECU 14m performs a reduction process for the risk level R. This reduction process is a process for appropriately reducing a risk level LV of the preliminary collision avoidance control (described later) that is permitted according to the risk level R, based on the relative relationship between the host vehicle M and the oncoming moving object O. For example, even if the oncoming moving object O is significantly swaying and the risk level R of the oncoming moving object O entering the traveling lane of the host vehicle M is high, if the oncoming moving object O is located far away, the possibility of the host vehicle M colliding with the oncoming moving object O is low. Therefore, in such a case, the traveling_ECU 14m reduces the risk level LV of the preliminary collision avoidance control that is permitted according to the risk level R, in order to prevent excessive execution of the preliminary collision avoidance control.

[0150] This downsampling process is executed, for example, according to the flowchart of the downsampling subroutine shown in FIG. 15.

[0151] When the subroutine starts, in step S301, the traveling ECU 14m checks whether the vertical collision prediction time TTCz with respect to the oncoming moving body O is less than a preset fourth threshold value Tth4 (where Tth1 < Tth4).

[0152] And, in step S301, when it is determined that the vertical collision prediction time TTCz is equal to or greater than the fourth threshold value Tth4 (step S301: NO), the traveling ECU 14m proceeds to step S302.

[0153] In step S302, after the traveling ECU 14m permits the pre-collision avoidance control corresponding to when the risk level R is "2" or less, it exits the subroutine. As a result, the traveling ECU 14m permits up to the pre-collision avoidance control corresponding to when the risk level R is "2", even if the current risk level R is "9". Also, for example, when the current risk level R is "2", the traveling ECU 14m permits the pre-collision avoidance control corresponding to when the risk level R is "2". In the present embodiment, the pre-collision avoidance control corresponding to when the risk level R is "2" or less is the collision avoidance control with a risk level LV = 1 associated with the "caution area" in the risk determination area.

[0154] On the other hand, in step S301, when it is determined that the vertical collision prediction time TTCz is less than the fourth threshold value Tth4 (step S301: YES), the traveling ECU 14m proceeds to step S303.

[0155] In step S303, the traveling ECU 14m checks whether the vertical collision prediction time TTCz is less than a preset fifth threshold value Tth5 (where Tth1 ≤ Tth5 < Tth4).

[0156] Then, in step S303, when it is determined that the longitudinal collision prediction time TTCz is equal to or greater than the fifth threshold value Tth5 (step S303: NO), the traveling_ECU 14m proceeds to step S304.

[0157] In step S304, the traveling_ECU 14m 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 14m 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 14m 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 a risk level LV=2 associated with the "warning zone" in the risk determination zone.

[0158] On the other hand, if it is determined in step S303 that the longitudinal collision prediction time TTCz is smaller than the fifth threshold value Tth5 (step S303: YES), the traveling_ECU 14m proceeds to step S305.

[0159] In step S305, the traveling_ECU 14m 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 14m 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 14m 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 14m 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.

[0160] 13, when the process proceeds from step S105 to step S106, the travel_ECU 14m 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 a risk level LV=3 in an emergency such as when the oncoming moving object O continues to move directly toward the host vehicle M.

[0161] This forced control intervention determination is executed, for example, according to a forced control intervention determination subroutine shown in FIG.

[0162] When the subroutine starts, in step S401, the travel_ECU 14m 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).

[0163] Then, in step S401, if it is determined that the oncoming moving object O is not moving directly toward the host vehicle M (step S401: NO), the travel_ECU 14m exits the subroutine.

[0164] On the other hand, in step S401, if it is determined that the oncoming moving object O is moving directly toward the host vehicle M (step S401: YES), the travel_ECU 14m proceeds to step S402.

[0165] In step S402, the travel_ECU 14m corrects the risk degree R for the oncoming moving object O to "9", and corrects the allowable risk level LV for the oncoming moving object O to "3", for example, and then exits the subroutine.

[0166] 13, when the process proceeds from step S106 to step S107, the travel_ECU 14m 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, a risk level LV currently allowed for the oncoming moving object O and a current risk level R currently set for the oncoming moving object O.

[0167] Here, for example, as shown in FIG. 20, when 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 14m 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 14m 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 14m prohibits avoidance control in the lateral direction (the vehicle width direction of the host vehicle M) for the oncoming moving body O.

[0168] Also, for example, as shown in Figure 20, 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 traveling_ECU 14m prohibits the output of an alarm or the like to notify the driver of the presence of the oncoming moving body O.

[0169] 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 14m permits, for example, first acceleration suppression control instead of brake control as avoidance control in the longitudinal direction (front-rear direction of the host vehicle M) 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.

[0170] 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 traveling_ECU 14m permits, for example, steering control within a range in which the host vehicle M does not deviate from the traveling 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, about 10 deg / s.

[0171] Also, for example, as shown in Figure 20, 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 traveling_ECU 14m sets an alarm or the like to notify the driver of the presence of the oncoming moving body O.

[0172] 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 14m 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 the host vehicle M is about to accelerate). The second acceleration suppression amount is set, for example, based on a preset map or the like, so as to increase 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.

[0173] Furthermore, when the risk level R is greater than "2" and control up to the risk level LV=2 is permitted for the oncoming moving object O, the travel_ECU 14m 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.

[0174] Also, for example, as shown in Figure 20, 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 traveling_ECU 14m sets an alarm or the like to notify the driver of the presence of the oncoming moving body O.

[0175] 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 14m 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.

[0176] 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 14m 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 180 deg / s.

[0177] When the process proceeds from step S107 to step S108, the travel_ECU 14m 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.

[0178] Then, in step S108, if it is determined that control intervention is not necessary (step S108: NO), the traveling_ECU 14m exits the routine.

[0179] On the other hand, if it is determined in step S108 that control intervention is necessary (step S108: YES), the traveling_ECU 14m proceeds to step S109.

[0180] In step S109, the traveling_ECU 14m checks whether the oncoming moving object O has entered the target traveling area Am of the host vehicle M.

[0181] Then, in step S109, if it is determined that the oncoming moving object O is not present within the target traveling area Am of the host vehicle M (step S109: NO), the traveling_ECU 14m proceeds to step S110.

[0182] In step S110, the traveling_ECU 14m executes the preliminary collision avoidance control, and then exits the routine. That is, the traveling_ECU 14m executes the preliminary collision avoidance control based on the control amount set in step S107.

[0183] On the other hand, in step S109, if it is determined 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 14m proceeds to step S111.

[0184] In step S111, the travel_ECU 14m shifts the control for the oncoming moving object O from the preliminary collision avoidance control to the emergency collision avoidance control, and then exits the routine.

[0185] According to this embodiment, the travel_ECU 14o of the oncoming moving object O calculates a risk level R that the oncoming moving object O poses to surrounding vehicles based on at least one of a history of the behavior of the oncoming moving object O relative to a marking line that divides an oncoming lane and the behavior of the driver driving the oncoming moving object O, and causes the light source unit 38 to emit light in a preset emission pattern toward the surroundings in accordance with the risk level R. Meanwhile, the travel_ECU 14m of the host vehicle M acquires the risk level R of the oncoming moving object O based on the emission pattern of the light source unit 38. Furthermore, the travel_ECU 14m recognizes the oncoming moving object O as an obstacle in accordance with 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.

[0186] 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.

[0187] Furthermore, the risk level R for an oncoming moving object O is acquired based on the light emission pattern of the light source unit 38 provided on the oncoming moving object O. Therefore, the travel_ECU 14m can accurately recognize an oncoming moving object O with a high risk level R. That is, for example, when multiple oncoming moving objects O are traveling in a line on the oncoming lane, it is expected that it will be difficult to accurately associate each oncoming moving object O with each risk level R in a configuration in which the host vehicle M receives the risk level R of each oncoming moving object O via wireless communication. In contrast, in the present embodiment, the risk level R is acquired based on the light emission pattern of the light emitting unit 38 provided on each oncoming moving object O, and therefore it is possible to accurately associate each oncoming moving object O with each risk level R.

[0188] Furthermore, by adopting a configuration in which the risk level R is transmitted by the light-emitting unit 38, it is possible to easily apply a configuration in which the risk level R is notified to surrounding vehicles, etc., even to vehicles that do not have wireless communication capabilities. In addition, the configuration of the light-emitting unit 38, etc., can be easily attached to a vehicle by retrofitting, etc.

[0189] Furthermore, by adopting a configuration in which the risk level R is notified by the light emission pattern of the light source unit 38, stable information transmission is possible even in a situation in which wireless communication is unstable due to radio wave interference or the like.

[0190] Furthermore, by transmitting information using light emission patterns, there is no need to worry about data tampering, as occurs with wireless communication, and it is also superior in terms of security compared to wireless communication.

[0191] In this case, the risk level R is calculated outside the host vehicle M. That is, the risk level R is calculated in the travel_ECU 14o of the oncoming moving object O itself, which is another vehicle, etc. Therefore, it is possible to accurately grasp the risk level R caused by the behavior of the oncoming moving object O, which is difficult to recognize using the stereo camera 11, which is an autonomous sensor of the host vehicle M, or the behavior of the driver driving the oncoming moving object O, etc.

[0192] Furthermore, the traveling_ECU 14o calculates risk level intermediate values ​​Rt-2, Rt-1, and Rt for the oncoming moving object O at timings t-2, t-1, and t, respectively, based on the history of the lane marking lateral position calculated for each preset section (for example, for each past time T).The traveling_ECU 14o then calculates the sum of the risk level intermediate values ​​Rt-2, Rt-1, and Rt as the risk level R.This makes it possible to accurately calculate the risk level R due to the behavior of the oncoming moving object O, such as swaying.

[0193] At this time, the traveling_ECU 14o calculates the lane marking lateral positions a, b of the oncoming moving object O relative to the left and right lane markings that define the oncoming lane.The traveling_ECU 14o then calculates the risk level intermediate values ​​Rt-2, Tt-1, Rt at each timing t-2, t-1, t based on the difference Δx between the average values ​​a_ave, b_ave of the lane marking lateral positions a, b calculated for each preset section.This makes it possible to accurately recognize the deviation of the oncoming moving object O from the center of the oncoming lane, regardless of the size of the oncoming moving object O.

[0194] In addition, the travel_ECU 14m performs upper limit processing on the risk level R. This makes it possible to prevent unnecessary preliminary collision avoidance control from being performed.

[0195] Furthermore, the travel_ECU 14m 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 realizing appropriate preliminary collision avoidance control for the oncoming moving object O.

[0196] 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.

[0197] In the above-described embodiment, the host vehicle M and the oncoming moving object O are relative entities that change depending on the reference vehicle. Therefore, in the following description, the "host vehicle M" can be read as the "oncoming moving object O," and the "oncoming moving object O" can be read as the "host vehicle M."

[0198] 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.

[0199] For example, the functions of the lateral position calculation unit, risk level calculation unit, and transmitter can be provided in infrastructure equipment (roadside units, etc.) installed at set intervals along the road. In this case, the infrastructure equipment includes, for example, a configuration equivalent to the camera unit 10 and a configuration equivalent to the transceiver 39.

[0200] Furthermore, even if some constituent elements are deleted from all the constituent elements shown in the above-mentioned form, if the stated problem can be solved and the stated effect can be obtained, the configuration from which these constituent elements are deleted can be extracted as an invention. [Explanation of symbols]

[0201] 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 38... Light source unit 100... Driving assistance system M: Vehicle (own vehicle) O … Oncoming moving object

Claims

1. a risk level calculation unit that calculates a risk level that the host vehicle poses to surrounding vehicles based on at least one of a history of behavior of the host vehicle relative to a lane marking that divides the lane in which the host vehicle is traveling and a behavior of a driver who drives the host vehicle; and a light source unit that emits light in a predetermined light emission pattern according to the risk level toward the periphery of the vehicle, The risk level calculation unit calculates the distance from the left and right lane markings that divide the driving lane for each predetermined section to the side edge of the vehicle as the lateral position relative to the left and right lane markings, calculates intermediate risk levels for the vehicle based on the history of the lateral positions relative to the lane markings, and calculates the sum of the intermediate risk levels as the risk level.

2. a risk level calculation unit that calculates a risk level that the host vehicle poses to surrounding vehicles based on at least one of a history of behavior of the host vehicle relative to a lane marking that defines the lane in which the host vehicle is traveling and a behavior of a driver who drives the host vehicle; and a light source unit that emits light in a predetermined light emission pattern according to the risk level toward the periphery of the vehicle; a risk level acquisition unit that acquires a risk level calculated for an oncoming moving object that is moving on an oncoming lane adjacent to the lane in which the vehicle is traveling with a speed component in the opposite direction to the traveling direction of the vehicle, based on a light emission pattern of a light source unit provided on the oncoming moving object; an emergency collision avoidance control unit that, when it is determined that there is a high possibility that the host vehicle will collide with an obstacle, performs emergency collision avoidance control to avoid collision with the obstacle; 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, and performs preliminary collision avoidance control prior to the emergency collision avoidance control for the oncoming moving object recognized as the obstacle, The risk level calculation unit calculates the distance from the left and right lane markings that divide the driving lane for each predetermined section to the side edge of the vehicle as the lateral position relative to the left and right lane markings, calculates intermediate risk levels for the vehicle based on the history of the lateral positions relative to the lane markings, and calculates the sum of the intermediate risk levels as the risk level.

3. a risk level calculation unit mounted on an oncoming moving object that moves on an oncoming lane adjacent to the vehicle's travel lane with a speed component in the opposite direction to the vehicle's travel direction, the risk level calculation unit calculating a risk level that the oncoming moving object poses to surrounding vehicles based on at least one of a history of the behavior of the oncoming moving object relative to a dividing line that divides the oncoming lane or the behavior of a driver driving the oncoming moving object; a light source unit mounted on the opposing moving body and configured to emit light in a predetermined light emission pattern according to the risk level toward the periphery of the opposing moving body; a risk level acquisition unit mounted on the host vehicle and acquiring the risk level of the oncoming moving object based on the light emission pattern of the light source unit; an emergency collision avoidance control unit mounted on the host vehicle, which, when it is determined that there is a high possibility that the host vehicle will collide with an obstacle, performs emergency collision avoidance control to avoid collision with the obstacle; a preliminary collision avoidance control unit that is mounted on the host vehicle, that recognizes the oncoming moving object as the obstacle according to the risk level, and that performs preliminary collision avoidance control prior to the emergency collision avoidance control for the oncoming moving object that has been recognized as the obstacle, The risk level calculation unit calculates the distance from the left and right lane markings that divide the driving lane for each predetermined section to the side edge of the vehicle as the lateral positions relative to the left and right lane markings, calculates intermediate risk levels for the oncoming moving object based on the history of the lateral positions relative to the lane markings, and calculates the sum of the intermediate risk levels as the risk level.

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