JP2018197048A - Collision avoidance control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accurately determine whether or not an avoidance route is a safe traveling route. A collision avoidance control device includes an avoidance route setting means for setting an avoidance route for avoiding a collision with a front obstacle, a reliability calculation means for calculating the reliability of the avoidance route, and an avoidance route. The automatic steering control means for determining whether or not to execute the automatic steering and the unit region 62 formed by dividing the region in front of the vehicle into a plurality of regions are specified as an obstacle region or an unknown region. A unit area specifying means is provided. At the same distance from the own vehicle, the obstacle area is set to be more costly than the unknown area. The reliability calculation means calculates the avoidance area cost based on the number and cost of obstacle areas existing in the avoidance area including the avoidance route and the number and cost of unknown areas, and trusts the avoidance route based on the avoidance area cost. Calculate the degree. [Selection diagram] FIG. 5A

Description

  The present invention relates to a collision avoidance control apparatus that performs control for avoiding or reducing the collision of a vehicle with an obstacle existing in front of the vehicle.

  2. Description of the Related Art Conventionally, a collision avoidance control device that performs control (collision avoidance control) for avoiding or reducing the collision of a vehicle with an obstacle existing in front of the vehicle is known. The collision avoidance control device uses automatic braking control (control for automatically applying braking force to the vehicle) or automatic braking as collision avoidance control when there is an obstacle that may cause the vehicle to collide in front of the vehicle. Automatic steering control with control (control for automatically changing the turning angle of the steering wheel of the vehicle) is executed. When executing the automatic steering control, the collision avoidance control device sets in advance an avoidance route that is a route for avoiding a collision with an obstacle, and the vehicle travels along the avoidance route. To control. Hereinafter, the vehicle equipped with the collision avoidance control device is also referred to as “own vehicle”.

  In such a collision avoidance control device, when the above-described automatic steering control is performed when another obstacle exists on the avoidance route, the obstacle avoidance that exists in front of the host vehicle before the execution of the control. Even if collision avoidance can be achieved, new control must be performed to avoid a collision with another obstacle on the avoidance path, and it may not be possible to avoid collision properly or unnatural (continuous) There is a possibility of collision avoidance. In this case, the driver of the own vehicle may be uncomfortable or distrustful, which is not preferable.

  Therefore, the collision avoidance control device (hereinafter referred to as “conventional device”) disclosed in Patent Document 1 does not execute automatic steering control when another obstacle exists on the avoidance route, and performs automatic braking control. It is configured to perform collision avoidance only. According to the conventional device, in order to determine whether or not the avoidance route is a safe travel route before executing the automatic steering control, there is a possibility that inappropriate or unnatural collision avoidance is executed by the automatic steering control. It is described that it can be reduced.

JP 2007-137116 A

  The conventional device determines whether the avoidance route is a safe travel route based only on whether there is an obstacle on the avoidance route. However, with this configuration, it may not be possible to accurately determine whether the avoidance route is a safe travel route. That is, for example, if there is a depression or an inclined surface on the road surface on the avoidance route that does not allow the vehicle to travel safely even if there are no obstacles on the avoidance route, the avoidance route Is not a safe route. However, according to the configuration of the conventional device, such an avoidance route may be determined to be a safe travel route, and thus the determination accuracy may be reduced.

  The present invention has been made to address the above-described problems. That is, one of the objects of the present invention is to provide a collision avoidance control device that can accurately determine whether or not an avoidance route is a safe travel route.

A collision avoidance control apparatus according to the present invention (hereinafter also referred to as “the present invention apparatus”)
Mounted on the vehicle,
An obstacle, a road surface, and a white line are detected based on parallax information acquired from the captured image in front of the vehicle captured by the two camera sensors and pixel information including a luminance value, and the obstacle, the road surface, and the white line are detected. Peripheral information acquisition means for acquiring the position as peripheral information;
Among the detected obstacles, there is a front obstacle that is an obstacle whose predicted collision time is estimated to be required before the vehicle collides in the forward direction of the vehicle, which is equal to or less than a predetermined first time threshold. An avoidance route setting means for setting an avoidance route for avoiding a collision with the front obstacle,
Reliability calculation means for calculating a reliability that is a measure indicating whether the avoidance route is safe as a travel route of the vehicle;
Automatic braking control for executing automatic braking control for automatically applying a braking force to the vehicle when the predicted collision time to the forward obstacle is not more than a predetermined second time threshold which is not more than the first time threshold. Means,
When the predicted collision time to the forward obstacle reaches a predetermined third time threshold value that is equal to or less than the second time threshold value, the vehicle is in the automatic braking control and is reduced by the automatic braking control. Determining whether or not a specific condition is satisfied that a braking distance based on speed is longer than a distance to the forward obstacle and the reliability of the avoidance path is equal to or greater than a predetermined reliability threshold; If it is determined that the condition is satisfied, automatic steering control is executed to automatically change the turning angle of the steering wheel of the vehicle so that the vehicle travels along the avoidance route, and the specific condition is not satisfied. If it is determined, automatic steering control means that does not execute the automatic steering control,
Is provided.

  In the device according to the present invention, when there is a front obstacle whose predicted collision time is equal to or less than the first time threshold, the avoidance path setting unit sets an avoidance path for avoiding a collision with the front obstacle, and the reliability The calculating means calculates the reliability of the avoidance route. Then, the automatic steering control means determines whether or not the specific condition is satisfied when the predicted collision time to the front obstacle becomes the third time threshold. This specific condition includes a condition that the reliability calculated by the reliability calculation means is equal to or higher than a reliability threshold. When it is determined that the specific condition is satisfied, the automatic steering control means performs automatic steering control along the avoidance path.

  In such a collision avoidance control device, it is determined for each calculation cycle whether another obstacle exists on the avoidance route, and if there is no obstacle, the avoidance route is determined to be safe, When an object exists, it is determined that the avoidance route is safe. However, the avoidance path may not be safe even if there are no obstacles on the avoidance path (specifically, when a depression or an inclined surface is formed on the road surface on the avoidance path). . The conventional collision avoidance control device is not preferable because there is a possibility that the avoidance route is safe even in such a case. There is a demand for a technique for determining whether or not an avoidance route is a safe travel route with higher accuracy than in the past.

Therefore, the device of the present invention is
Furthermore, it is unknown whether each of the unit areas when the area in front of the vehicle is divided into a plurality of unit areas is an obstacle area where an obstacle exists, or whether the vehicle can travel safely. A unit region specifying means for specifying whether it is a certain unknown region based on the peripheral information;
With
The unit area has a different cost depending on the type of area, and when the distance from the vehicle to the obstacle area and the distance from the vehicle to the unknown area are substantially the same, The cost is set higher than the cost of the unknown area,
The reliability calculation means includes
A region through which the vehicle passes when the vehicle travels along the avoidance path for each calculation period until the predicted collision time to the front obstacle reaches the third time threshold from the first time threshold. Based on the number and cost of the obstacle area existing in the avoidance area including, and the number and cost of the unknown area, to calculate the avoidance area cost that is a measure indicating the risk of the avoidance area,
The avoidance area cost is set to increase as the number of obstacle areas and the number of unknown areas existing in the avoidance area increase.
When the avoidance area cost is equal to or higher than a predetermined cost threshold, the reliability is calculated as a value obtained by subtracting a predetermined value from the reliability of the immediately preceding calculation cycle, and when the avoidance area cost is less than the cost threshold, The reliability is calculated as a value obtained by adding a predetermined value to the reliability of the previous calculation cycle.
It is configured as follows.

  According to the device of the present invention, the unit area specifying means only specifies whether each of the unit areas when the area in front of the vehicle is divided into a plurality of unit areas is an obstacle area where an obstacle exists. Instead, it also specifies “whether it is an area where the vehicle can travel safely or is an unknown area”. Here, the unknown region typically represents a region where a depression or an inclined surface is formed. The reliability calculation means presents the avoidance area cost, which is a measure of the risk of the avoidance area (the area including the avoidance path), in the avoidance area as well as the number and cost of the obstacle areas existing in the avoidance area. The number of unknown areas to be calculated and the cost are also calculated. Then, the reliability calculation means subtracts the reliability by a predetermined value from the reliability of the immediately preceding calculation cycle when the avoidance area cost is equal to or higher than the cost threshold, and when the avoidance area cost is less than the cost threshold, A predetermined value is added to the reliability of the immediately preceding calculation cycle.

  According to this configuration, the reliability of the avoidance path reflects not only the number and cost of obstacle regions but also the number and cost of unknown regions. In addition, when the unknown area and the obstacle area exist at substantially the same distance from the vehicle, the cost of the obstacle area is set higher than the cost of the unknown area. The obstacle area has a higher degree of risk as a travel route of the vehicle than the unknown area. For this reason, the number of unknown areas and their costs are reflected in the reliability of the avoidance path, and moreover, the risk level of the avoidance area is more accurately determined by setting the size relationship between the obstacle area and the unknown area as described above. The avoidance area cost reflected in can be calculated. That is, the reliability that more accurately reflects the safety level of the avoidance path can be calculated. As a result, whether or not the avoidance route is a safe travel route can be determined with higher accuracy than in the past.

  In the above description, in order to help the understanding of the invention, the reference numerals used in the embodiments are attached to the configuration of the invention corresponding to the embodiment in parentheses, but each constituent element of the invention is the reference numeral. It is not limited to the embodiment defined by.

1 is a collision avoidance control apparatus (hereinafter referred to as “first apparatus”) according to a first embodiment of the present invention. It is a figure which shows the initial state of a grid map. It is a figure which shows the initial state of a parallax voting map. It is a figure used in order to demonstrate the method of determining whether an obstruction exists ahead of the advancing direction of the own vehicle. When a front obstacle is a continuous obstacle, it is a figure which shows the avoidance path | route (refer thick line) set when TTC became time threshold value Tth1. When a front obstacle is a discontinuous obstacle, it is a figure which shows the avoidance path | route (refer thick line) set when TTC became time threshold value Tth1. It is a figure used in order to explain a method of searching an obstacle field where an obstacle which continues with a front obstacle exists. It is a figure which shows the line segment obtained by linearly approximating a connection area | region and a connection area | region to a longitudinal direction. It is a figure used in order to demonstrate the calculation method of the avoidance area cost in case a front obstacle is a continuous obstacle. It is a flowchart (the 1) which shows the routine which CPU of the collision avoidance ECU of 1st apparatus (henceforth "CPU of 1st apparatus") performs. It is a flowchart (the 2) which shows the routine which CPU of 1st apparatus performs. It is a flowchart (the 3) which shows the routine which CPU of 1st apparatus performs. It is a flowchart (the 4) which shows the routine which CPU of a 1st apparatus performs. It is a flowchart (the 5) which shows the routine which CPU of 1st apparatus performs. The collision avoidance control device (hereinafter referred to as “second device”) according to the second embodiment of the present invention is used to describe a method for determining whether or not an avoidance route set as a travel route is safe. FIG.

(First embodiment)
FIG. 1 is a schematic system configuration diagram of a collision avoidance control device (hereinafter also referred to as “first device”) according to a first embodiment of the present invention. When it is necessary to distinguish a vehicle equipped with the first device from other vehicles, it is referred to as “own vehicle”. The first device is a device that supports the driving of the driver by performing collision avoidance control for avoiding a collision with an obstacle that is highly likely to collide with the host vehicle.

  The first device includes a collision avoidance ECU 10. Note that ECU is an abbreviation for “Electric Control Unit”, and includes a microcomputer as a main part. The microcomputer includes a CPU 31 and storage devices such as a ROM 32 and a RAM 33. The CPU 31 implements various functions by executing instructions (programs, routines) stored in the ROM 32.

  The first device further includes a camera sensor 11, a vehicle state sensor 12, a brake ECU 20, a brake sensor 21, a brake actuator 22, a steering ECU 40, a motor driver 41, a steering motor 42, an alarm ECU 50, and a buzzer 51. The collision avoidance ECU 10 is connected to the camera sensor 11 and the vehicle state sensor 12, and can exchange data (communicable) with the brake ECU 20, the steering ECU 40, and the alarm ECU 50 via a communication / sensor system CAN (Controller Area Network). It is connected.

  The camera sensor 11 includes an in-vehicle stereo camera device (not shown) that images the front of the host vehicle. The in-vehicle stereo camera device is provided near the center in the vehicle width direction of the front end of the roof of the host vehicle, and includes a left camera disposed on the left side of the vehicle longitudinal axis and a right camera disposed on the right side of the vehicle longitudinal axis. . The left camera captures an area in front of the host vehicle every time a predetermined time elapses, and outputs a left image signal representing the captured left image to the collision avoidance ECU 10. Similarly, the right camera captures an area in front of the host vehicle every time a predetermined time elapses, and outputs a right image signal representing the captured right image to the collision avoidance ECU 10.

  The vehicle state sensor 12 is a sensor that acquires vehicle state information related to the traveling state of the host vehicle. The vehicle state sensor 12 detects a vehicle speed sensor that detects the speed of the host vehicle (that is, a vehicle speed), an acceleration sensor that detects acceleration in the front-rear direction and the left-right (lateral) direction of the host vehicle, and detects a yaw rate Y of the host vehicle. A yaw rate sensor, a turning angle sensor for detecting the turning angle of the steered wheels, and the like. The value of the yaw rate Y is positive when the vehicle turns in the right direction, and negative when the vehicle turns in the left direction. The vehicle state sensor 12 outputs vehicle state information to the collision avoidance ECU 10 every time a predetermined time elapses.

  The collision avoidance ECU 10 stores a grid map divided into a plurality of rectangular unit areas. The grid map corresponds to the imaging range (that is, the area in front of the host vehicle) of the in-vehicle stereo camera device (details will be described later). The collision avoidance ECU 10 generates a parallax image having parallax information and pixel information including a luminance value from the left image signal and the right image signal output from the camera sensor 11. The collision avoidance ECU 10 is based on the parallax information and the pixel information. The unit area of the grid map includes an obstacle area where an obstacle exists, a white line area where a white line exists, and a safety area where the host vehicle can safely travel. It is specified (classified) as an area and an unknown area that does not correspond to any of the above areas (that is, an area where it is unknown whether the host vehicle can travel safely). Different cost is set for each unit area according to the type of area. In addition, the collision avoidance ECU 10 calculates the relative speed and distance of the obstacle with respect to the host vehicle based on the parallax information. In this specification, “obstacles” means moving three-dimensional objects (vehicles, pedestrians, bicycles, etc.) and fixed three-dimensional objects (guardrails, side walls, median strips, street trees, etc.) existing around the host vehicle. Represent.

  In addition, when there is an obstacle region ahead of the traveling direction of the host vehicle, the collision avoidance ECU 10 is a continuous obstacle having a continuity or a discontinuity having no continuity. Determine if it is an obstacle. Note that the continuous obstacle typically represents a guardrail, a side wall, or a median, and the non-continuous obstacle typically represents a preceding vehicle. When it is determined that the obstacle is a continuous obstacle, the collision avoidance ECU 10 calculates the inclination of the continuous obstacle with respect to the traveling direction of the host vehicle, and avoids the collision with the continuous obstacle based on the inclination and the vehicle speed. Set an avoidance route to do. On the other hand, when it is determined that the obstacle is a discontinuous obstacle, the collision avoidance ECU 10 passes between the discontinuous obstacle and a white line (a white line constituting the own lane in which the host vehicle is traveling). Therefore, a lateral movement distance (movement distance in the vehicle width direction) necessary for this is calculated, and an avoidance path for avoiding a collision with the discontinuous obstacle is set based on the lateral movement distance and the vehicle speed.

  Further, the collision avoidance ECU 10 refers to the grid map and calculates a cost (avoidance area cost) of an avoidance area including an area that the vehicle will pass when traveling along the avoidance route. The avoidance area cost is calculated based on the number and cost of the four types of areas existing in the avoidance area. The collision avoidance ECU 10 calculates a reliability that is a measure indicating whether or not the avoidance route is safe as the traveling route of the host vehicle based on the avoidance region cost. Then, at a predetermined timing, based on the reliability and other conditions described later, it is determined whether or not to execute the automatic steering control so that the host vehicle travels along the avoidance route. When the collision avoidance ECU 10 determines to execute the automatic steering control, the collision avoidance ECU 10 calculates an automatic steering control amount and transmits an automatic steering request signal including the control amount to the steering ECU 40. In addition, the collision avoidance ECU 10 calculates a control amount for automatically braking the host vehicle at a predetermined timing, and transmits an automatic braking request signal including the control amount to the brake ECU 10 or alerts the driver. Is transmitted to the alarm ECU 50.

  The brake ECU 20 is connected to a plurality of brake sensors 21 and receives detection signals from these sensors. The brake sensor 21 is a sensor that detects a parameter used when controlling a braking device (not shown) mounted on the host vehicle. The brake sensor 21 includes a brake pedal operation amount sensor, a wheel speed sensor that detects the rotational speed of each wheel, and the like.

  The brake ECU 20 is connected to the brake actuator 22. The brake actuator 22 is a hydraulic control actuator. The brake actuator 22 is arranged in a hydraulic circuit (both not shown) between a mass cylinder that pressurizes hydraulic oil by the depression force of the brake pedal and a friction brake device including a well-known wheel cylinder provided on each wheel. Established. The brake actuator 22 adjusts the hydraulic pressure supplied to the wheel cylinder. The brake ECU 20 drives the brake actuator 22 to generate a braking force (friction braking force) on each wheel, and adjusts the acceleration (negative acceleration, that is, deceleration) of the host vehicle.

  In addition, the brake ECU 20 can adjust the acceleration of the host vehicle by driving the brake actuator 22 based on a signal (automatic braking request signal) transmitted from the collision avoidance ECU 10.

  The steering ECU 40 is a known control device for an electric power steering system, and is connected to a motor driver 41. The motor driver 41 is connected to the steering motor 42. The steering motor 42 is incorporated in the “steering mechanism including a steering handle, a steering shaft coupled to the steering handle, a steering gear mechanism, and the like” of the host vehicle SV. The steered motor 42 generates torque by the electric power supplied from the motor driver 41, and applies the steering assist torque by this torque or steers the left and right steered wheels.

  In addition, the steering ECU 40 adds steering assist torque by controlling the motor driver 41 based on a signal (automatic steering request signal) transmitted from the collision avoidance ECU 10 to generate torque in the steering motor 42. Or steer left and right steering wheels.

  The alarm ECU 50 is connected to the buzzer 51. The alarm ECU 50 alerts the driver by sounding the buzzer 51 based on a signal (attention request signal) transmitted from the collision avoidance ECU 10.

(Details of operation)
Next, details of the operation of the first device will be described.
<Identification of unit area in grid map>
The first device stores a grid map 60 shown in FIG. 2 in advance in the RAM of the collision avoidance ECU 10. The grid map 60 corresponds to a region obtained by converting the region of the imaging range of the in-vehicle stereo camera device into a plan view. The grid map 60 is divided into a plurality of lattice unit regions 62. The first device has a period from when an unillustrated engine switch (ignition key switch) of the host vehicle is turned on until it is turned off (hereinafter also referred to as “engine on period”), for each predetermined calculation cycle. The unit area 62 in the grid map 60 is specified as one of the following four types of areas: an obstacle area, a white line area, an unknown area, and a safety area. The area of the unit area 62 is specified by using a known method (for example, Japanese Patent Laid-Open No. 2006-206775 and Keiji Miyoshi, “Automotive Driving Support System Using Stereo Camera”, Information Processing Society of Japan Research Report, 2013. (See January 23 of the year). This will be specifically described below.

  The first device generates a parallax image having parallax information and pixel information including a luminance value based on the left image signal and the right image signal output from the camera sensor 11. Parallax information and pixel information are associated with each pixel constituting the parallax image. The first device stores a parallax voting map 70 shown in FIG. 3 in advance in the RAM of the collision avoidance ECU 10. The parallax voting map 70 has a plurality of rectangular blocks defined such that the horizontal side corresponds to the position in the horizontal direction (vehicle width direction) of the parallax image, and the vertical side corresponds to the size of the parallax. 72 is arranged. The first device votes (classifies) a pixel to the corresponding block 72 of the parallax voting map 70 based on the position of the pixel in the parallax image and the magnitude of the parallax of the pixel. Then, the first device, for each block 72 of the parallax voting map 70, the average value of parallax, the deviation of parallax, the average value of pixel coordinates in the vertical direction of the parallax image, and the deviation of pixel coordinates in the vertical direction of the parallax image. Is calculated.

  Based on the vertical distribution of pixels in each block 72 of the parallax voting map 70 (deviation of pixel coordinates in the vertical direction of the parallax image) and the distribution of parallax directions (deviation of parallax), the first device. Is set to any one of obstacle, road surface and unknown. That is, when the pixels having the same degree of parallax (distance) are distributed in a wide range in the vertical direction of the parallax image in the block 72 of the parallax voting map 70, the first device determines that the set of pixels is a failure. It is determined that the object is shown. In this case, the first device sets the attribute of the block 72 as an obstacle, and identifies the pixel classified into the block 72 as an obstacle candidate point.

  On the other hand, the first device distributes pixels having the same degree of parallax (distance) in the block 72 of the parallax voting map 70 in a narrow range in the vertical direction of the parallax image, and the parallax decreases (from the own vehicle). When the position of the pixel in the vertical direction of the parallax image rises smoothly (as the distance increases), it is determined that the set of pixels indicates the road surface. In this case, the first device sets the attribute of the block 72 to the road surface, and identifies the pixel classified into the block 72 as a road surface candidate point. On the other hand, the first device sets an unknown attribute to the block 72 that is not set to any attribute of the obstacle and the road surface, and specifies a pixel classified into the block 72 as an unknown candidate point. Note that the disparity information and the pixel information associated with the obstacle candidate point, the road surface candidate point, and the unknown candidate point all correspond to an example of “peripheral information”.

  In addition, the first device detects an edge using a known method based on pixel information included in the parallax image, and sets the parallax image of the edge. A white line is detected by selecting only a pair of edges that meet the white line and lane standards. The first device identifies a pixel present at a position detected as a white line as a white line candidate point. Note that the parallax information and the pixel information associated with the white line candidate points correspond to an example of “peripheral information”.

  The horizontal side and the vertical side of the grid map 60 are respectively at the horizontal position and the vertical position of the parallax image (strictly speaking, the vertical position when the parallax image is converted into a planar view image). It corresponds. The unit area 62 is, for example, an area corresponding to a range of 25 cm wide × 50 cm long. In FIG. 2, the center in the vehicle width direction at the front end of the host vehicle is located at a point 64. Each unit area 62 is set as an unknown area in the initial state.

  The first device plots the obstacle candidate point, the road surface candidate point, and the unknown candidate point in the parallax voting map 70 and the white line candidate point in the parallax image of the edge at corresponding positions on the grid map 60. Then, when there are obstacle candidate points in the unit area 62 of the grid map 60, the first device stores in the unit area 62 regardless of the presence / absence of road candidate points, white line candidate points, and unknown candidate points. Determines that an obstacle exists and changes (identifies) the unit area from the unknown area to the obstacle area. In addition, when the obstacle candidate point does not exist in the unit region 62 of the grid map 60 and the white line candidate point exists, the first device relates to the presence or absence of the road surface candidate point and the unknown candidate point. First, it is determined that a white line exists in the unit area 62, and the unit area 62 is changed (specified) from the unknown area to the white line area. Furthermore, the first device has no obstacle candidate point and white line candidate point in the unit area 62 of the grid map 60, and if there is a road surface candidate point, whether or not an unknown candidate point exists. The unit area 62 is determined to have a road surface, and the unit area 62 is changed (specified) from the unknown area to the road surface area. Furthermore, when only the unknown candidate point exists in the unit area 62 of the grid map 60, the first device determines that the unit area 62 does not correspond to any of the obstacle area, the white line area, or the road surface area. Then, the unit area 62 is maintained (specified) in the unknown area.

  Here, in the road surface region, there is a unit region 62 that cannot be said to be safe as the traveling road surface of the host vehicle (for example, a region in which a depression or an inclined surface is formed so that the host vehicle cannot travel safely on the road surface) 62. May exist. In addition, in the unknown area, there may be a unit area 62 that is safe as a traveling road surface of the host vehicle. Therefore, the first device uses, in a known manner, the parallax information and pixel information associated with the pixels (road surface candidate points or unknown candidate points) in the unit area 62 identified as the road surface area or the unknown area. Based on this, it is determined whether or not the road surface area and the unknown area are safe as the traveling road surface of the host vehicle. When it is determined that the vehicle is safe, the first device determines that the unit area 62 is safe as a traveling road surface of the host vehicle, and changes the unit area 62 from a road surface area or an unknown area to a safe area ( Identify. On the other hand, when it is determined that it is not safe, the first device determines that the unit area 62 is unclear as to whether the unit area 62 is safe as the traveling road surface of the host vehicle, and makes the unit area 62 a road surface area or unknown. Change or maintain (specify) from area to unknown area. The “disparity information and pixel information associated with pixels (road surface candidate points or unknown candidate points) in the unit area 62 identified as a road surface area or an unknown area” corresponds to an example of “peripheral information”. .

  In this way, the first device classifies each unit area 62 of the grid map 60 as one of an obstacle area, a white line area, a safety area, and an unknown area. Different costs are set for the unit area 62 depending on the type of area. This cost is a scale indicating the degree of danger when the host vehicle enters the unit area 62, and is set higher as the degree of danger is larger. The cost of the obstacle area is set to be the highest because the host vehicle may come into contact with the obstacle. The cost of the white line area is set next to the cost of the obstacle area because there is a possibility that the own vehicle may exceed the white line (depart from the own lane) and as a result, may contact the obstacle. . The cost of the unknown area is set next to the cost of the white line area because the possibility of the presence of an obstacle or white line is extremely low but it is unknown whether the road surface is safe. The cost of the safety area is set to zero. The first device stores the grid map 60 specified as one of the above four types of areas in the RAM of the collision avoidance ECU 10. The grid map 60 stored in the RAM is updated every calculation cycle.

<Awareness>
The first device determines whether there is an obstacle ahead of the traveling direction of the host vehicle for each calculation cycle during the engine-on period. Specifically, as shown in FIG. 4, the first device sets a virtual straight line 66 extending in the traveling direction TD from a point 64 representing the center of the host vehicle in the vehicle width direction on the grid map 60, and the virtual straight line 66. When the vehicle passes through the obstacle area, it is determined that there is an obstacle ahead of the traveling direction of the host vehicle. In this case, the first device calculates a predicted collision time TTC (Time To Collision), which is a time predicted to be required until the host vehicle collides with the obstacle when the vehicle continues traveling at the current vehicle speed. The TTC can be calculated by dividing the distance to the obstacle by the relative speed of the host vehicle with respect to the obstacle. The first device determines that the host vehicle may collide with the obstacle when TTC is equal to or less than a predetermined time threshold Tth0 and greater than a predetermined time threshold Tth1 smaller than the time threshold Tth0. The buzzer 51 is sounded to alert the driver. The time threshold value Tth0 is a threshold value for determining whether or not to call attention. When the driver performs a brake operation by alerting and as a result TTC becomes larger than the time threshold value Tth0, alerting is terminated. On the other hand, when the driver does not perform the brake operation even when the alert is issued, and as a result, the TTC is equal to or less than the time threshold value Tth1, the alert is terminated. In the following, an obstacle whose TTC is equal to or less than the time threshold value Tth0 is particularly referred to as a “front obstacle”.

<Setting avoidance route>
As shown in FIGS. 5A and 5B, when the TTC to the front obstacle becomes equal to or less than the time threshold Tth1, the first device operates until the TTC reaches a predetermined time threshold Tth3 smaller than the time threshold Tth1. Every time, avoidance routes r _A and r _B (indicated by bold lines in FIGS. 5A and 5B) for avoiding a collision with a front obstacle are set. The time threshold value Tth1 is a threshold value for determining whether to start setting the avoidance routes r _A and r _B , and the time threshold value Tth3 is whether or not the automatic steering control is performed along the avoidance routes r _A and r _B. This is a threshold value for determining whether or not the timing for determining whether or not has come. The avoidance paths r _A and r _B are only points P _A and P _B where the TTC is expected to become the time threshold Tth3 (that is, the “current relative speed with respect to the forward obstacle” multiplied by the “time threshold Tth3”). This is a route extending from the front obstacle). In other words, the host vehicle is assumed to go straight to the points P _A and P _B. When setting the avoidance routes r _A and r _B , the first device determines whether the front obstacle is a continuous obstacle CO or a non-continuous obstacle NCO, and uses different parameters based on the determination result. Avoidance routes r _A and r _B are set. The time threshold Tth1 corresponds to an example of “first time threshold”, and the time threshold Tth3 corresponds to an example of “third time threshold”.

  First, referring to FIG. 6, a method for determining whether a forward obstacle is a continuous obstacle CO having continuity or a non-continuous obstacle NCO having no continuity will be described. As shown in FIG. 6, the first device arranges the movable frame 68 having a predetermined size on the grid map 60 so that the obstacle area A where the front obstacle exists is located at the center. For example, the movable frame 68 corresponds to a range of 125 centimeters wide (length of five unit regions) × 250 centimeters long (length of five unit regions). Hereinafter, the obstacle area A located at the center of the movable frame 68 is referred to as “central obstacle area A”.

  Then, the first device searches for obstacle regions in order from the unit region 62 close to the central obstacle region A within the range of the movable frame 68. Specifically, the obstacle area is searched from the eight unit areas 62 adjacent to the central obstacle area A. For example, the first device searches for an obstacle region counterclockwise from the unit region 62ur located at the upper right of the central obstacle region A. If no obstacle area exists in the eight unit areas 62, the first device searches for the obstacle area from the sixteen unit areas 62 adjacent to the eight unit areas 62 on the outer periphery side. To do. When there is an obstacle area in the range of the movable frame 68, the first device moves the movable frame 68 so that the obstacle area becomes a new central obstacle area A, and the range of the movable frame 68 after the movement. Search for obstacle areas within. At this time, the obstacle area already set in the central obstacle area A is excluded from the search target.

  The first device searches for an obstacle region while moving the movable frame 68 in this way. When there is no obstacle area within the range of the movable frame 68 (except for the current and past central obstacle area A), the first device has previously set the obstacle in the central obstacle area A. The areas are connected to create one connected area 80 (see FIG. 7). At this time, if the obstacle regions are not adjacent to each other, the unit region 62 positioned between them is included in the connection region 80 (for example, the unit regions 62a, 62b, and 62c in FIG. 6 are included in the connection region 80). .

  If the connection area | region 80 is created, as shown in FIG. 7, the 1st apparatus will linearly approximate the connection area | region 80 to a longitudinal direction, and will calculate the length of the line segment 82 obtained by the linear approximation. And it is determined whether the length of the line segment 82 is more than a predetermined length threshold value. When the first device determines that the length of the line segment 82 is equal to or greater than the length threshold, the obstacle present in the connection region 80 has continuity, that is, determines that the obstacle is a continuous obstacle CO. On the other hand, when the first device determines that the length of the line segment 82 is less than the length threshold, the obstacle present in the connection region 80 does not have continuity, that is, is a discontinuous obstacle NCO. Is determined. The length threshold is set in advance to a value at which it is determined that the guardrail, the side wall, the median strip, and the like have continuity, and the vehicle, the pedestrian, the bicycle, and the like have no continuity.

Next, a method for setting the avoidance route r _A when it is determined that the front obstacle is the continuous obstacle CO will be described with reference to FIG. 5A. When the first device determines that the front obstacle is the continuous obstacle CO, the slope g [of the line segment 82 of the connection region 80 (not shown in FIG. 5A) with respect to the virtual straight line 66 extending in the traveling direction TD of the host vehicle. deg] is calculated. Hereinafter, the inclination g is also simply referred to as “inclination g of a continuous obstacle”. Then, set the slope g of a continuous obstacle CO, the vehicle speed, the avoidance path r _A based on. For the inclination g, an acute angle is adopted from two angles formed by the traveling direction TD of the host vehicle (that is, the virtual straight line 66) and the line segment 82 of the connection region 80. The value of the slope g is positive when the continuous obstacle CO extends obliquely forward to the right with respect to the own vehicle, and is negative when the continuous obstacle CO extends obliquely forward to the left with respect to the own vehicle. is there.

  The first device stores, in the ROM of the collision avoidance ECU 10, a map (yaw rate map) that defines the relationship between the gradient g and the vehicle speed and the yaw rate Y, and a map that defines the relationship between the gradient g and the vehicle speed and time t. (Time map) are stored in advance. The yaw rate map includes information on the yaw rate Y necessary for the host vehicle to avoid a collision with the continuous obstacle CO. The time map includes information on a time t at which the vehicle should continue traveling at the yaw rate Y obtained by referring to the yaw rate map in order to avoid a collision with the continuous obstacle CO. Note that the value of the yaw rate Y in the yaw rate map is positive when the slope g is positive, and is negative when the slope g is negative.

By applying the slope g and the vehicle speed of the continuous obstacle CO to both maps, the yaw rate Y and the time t during which the vehicle travels at the yaw rate Y are uniquely determined. Thus, the shape of the avoidance route r _A is uniquely determined. That is, “setting the avoidance route r _A ” is synonymous with “determining the yaw rate and the time t by applying the slope g and the vehicle speed of the continuous obstacle CO to the two maps”. The vehicle speed here is “the vehicle speed estimated at the point P _A (the start point of the avoidance route r _A )”. This vehicle speed can be estimated from “current vehicle speed” and “target deceleration by automatic braking control (described later)”, assuming that the current vehicle speed is maintained until a time point at which automatic braking control (described later) is executed. Hereinafter, the vehicle speed is referred to as “estimated vehicle speed” in order to distinguish it from the current vehicle speed.

In the yaw rate map, when the vehicle speed is constant, the absolute value of the yaw rate Y increases as the absolute value of the gradient g increases. When the vehicle speed increases, the absolute value of the yaw rate Y increases as the vehicle speed increases. Is set.
On the other hand, in the time map, when the vehicle speed is constant, the time t becomes longer as the absolute value of the inclination g becomes larger, and when the inclination g is constant, the time t becomes longer as the vehicle speed becomes larger. .

  An error based on the detection error occurs in the inclination g of the continuous obstacle CO and the vehicle speed. For this reason, the yaw rate map is created so that the yaw rate Y maintains a constant value even if the inclination g and the vehicle speed change within the error range depending on the calculation cycle. The same applies to the time map.

The first device stores the avoidance route r _A (in other words, the combination of the yaw rate Y and the time t) in the RAM of the collision avoidance ECU 10. Hereinafter, the combination of the yaw rate Y and the time t is also simply referred to as “(Y, t)”. As described above, if the first obstacle is a continuous obstacle CO when the TTC is equal to or less than the time threshold Tth1 even in the next calculation cycle (hereinafter, the calculation cycle is also simply referred to as “cycle”), the first device is as described above. The inclination g of the continuous obstacle CO is calculated, and the yaw rate Y and time t are determined based on the inclination g and the vehicle speed. The first device, a in the current period (Y, t), compared to the stored in the collision avoidance ECU10 of RAM (Y, t), if it is determined that the same change in the avoidance path _{r A} (That is, (Y, t) stored in the RAM is not updated). On the other hand, the first apparatus, (Y, t) in the current period if it is determined that the collision avoidance is stored in ECU10 of RAM (Y, t) is not the same as, newly set an avoidance route r _A (That is, (Y, t) stored in the RAM is updated to (Y, t) in the current cycle.)

Next, a method for setting the avoidance route r _B when it is determined that the front obstacle is a discontinuous obstacle NCO will be described with reference to FIG. 5B. When it is determined that the front obstacle is a discontinuous obstacle NCO, it is highly possible that the discontinuous obstacle NCO exists in the own lane. Therefore, the first device determines whether or not a route passing between the discontinuous obstacle NCO and the white line WL (the right white line RWL on the right side and the left white line LWL on the left side of the own lane) can be set. and sets the route when it is determined that can be set as a bypass route r _B.

Specifically, the first device determines, based on the parallax information, the position of the right end of the discontinuous obstacle NCO and the position of the left end of the right white line when the center of the vehicle width direction of the host vehicle is used as a reference. identified, and calculates the right side distance D _R is the horizontal distance between the discontinuous obstacle NCO and right white line from the difference between them. Similarly, the first device identifies the left end position of the discontinuous obstacle NCO and the right end position of the left white line, and the left lateral distance D _L between the discontinuous obstacle NCO and the left white line is determined from the difference between the two. Is calculated. The right transverse distance D _R as a positive value, the left transverse distance D _L is calculated as a negative value.

The first device determines a right transverse distance D _R, compares the absolute value of the left transverse distance D _L, the absolute value of the lateral distance the larger, whether a minimum passage length or longer. Here, the minimum passing length is the “predetermined margin width (because the own vehicle passes between the non-continuous obstacle NCO and the white line WL with a margin) in the“ vehicle width length W of the own vehicle ”. Is defined as the length obtained by adding the “required width”). When it is determined that the absolute value of the larger lateral distance is greater than or equal to the minimum passage length, the first device can set an avoidance route r _B that passes between the discontinuous obstacle NCO and the white line WL. judge. In this case, the first device calculates a lateral movement distance LD that is a distance that the host vehicle should move in the lateral direction based on the larger lateral distance (hereinafter, also simply referred to as “lateral distance”). Horizontal travel distance LD (if the right transverse distance D _R) transverse distance is positive case, is calculated as a positive value, when the lateral distance is negative (in the case of the left lateral distance D _L), calculated as a negative value Is done. Then, the avoidance route r _B is set based on the lateral movement distance LD and the vehicle speed. On the other hand, if it is determined that the absolute value of the larger lateral distance is less than the minimum passage length, the first device does not set the avoidance route r _B that passes between the discontinuous obstacle NCO and the white line WL. Determine that it is possible. In this case, the first device does not perform the setting of the bypass route r _B (described later).

When the forward obstacle is a non-continuous obstacle NCO, the avoidance path r _B first avoids a collision with the non-continuous obstacle NCO, and then does not deviate from the white line WL (stays in the own lane). Is set to be For this reason, in the avoidance route r _B , “route r _B1 for avoiding collision with the non-continuous obstacle NCO” and “route r _B2 for preventing deviation from the white line” are smoothly connected. It becomes a route. Hereinafter, the former route is referred to as “first avoidance route r _B1 ”, and the latter route is referred to as “second avoidance route r _B2 ”. The first avoidance route r _B1 extends from the point P _B where the TTC is expected to become the time threshold value Tth3, and the second avoidance route r _B2 becomes a route extending from the end point of the first avoidance route r _B1 .

The first device stores in the ROM of the collision avoidance ECU 10 a map defining the relationship between the lateral movement distance LD and vehicle speed for the first avoidance route r _B1 and the yaw rate Y, the lateral movement distance LD and vehicle speed, and the time t. , A map that defines the relationship between the lateral movement distance LD and vehicle speed for the second avoidance route r _B2 , and the yaw rate Y, the lateral movement distance LD and vehicle speed, and the relationship between time t And a map that prescribes
Hereinafter, in order to distinguish the yaw rate Y for the first avoidance route r _B1 and the yaw rate Y for the second avoidance route r _B2 , the former is referred to as “first yaw rate Y1”, and the latter is referred to as “second yaw rate Y2”. Called. In addition, in order to distinguish the time t for the first avoidance route r _B1 and the time t for the second avoidance route r _B2 , the former is referred to as “first time t1” and the latter is referred to as “second time t2”. Called. Further, the map of the first yaw rate Y1 and the map of the second yaw rate Y2 are referred to as “first yaw rate map” and “second yaw rate map”, respectively, and the map of the first time t1 and the map of the second time t2 are respectively These are referred to as “first time map” and “second time map”.

  The first yaw rate map includes information on the first yaw rate Y1 necessary for the host vehicle to avoid a collision with the discontinuous obstacle NCO. The first time map is information on the first time t1 at which the vehicle should continue traveling at the first yaw rate Y1 obtained by referring to the first yaw rate map in order to avoid a collision with the discontinuous obstacle NCO. including. The second yaw rate map includes information on the second yaw rate Y2 necessary for preventing the vehicle from deviating from the white line after avoiding a collision with the discontinuous obstacle NCO. The second time map includes information on the second time t2 at which the vehicle should continue traveling at the second yaw rate Y2 obtained by referring to the second yaw rate map in order to prevent the host vehicle from deviating from the white line. The value of the first yaw rate Y1 is positive when the lateral movement distance LD is positive, and is negative when the lateral movement distance LD is negative. On the other hand, the value of the second yaw rate Y2 is negative when the lateral movement distance LD is positive, and is positive when the lateral movement distance LD is negative.

By applying the lateral movement distance LD and the vehicle speed to the four types of maps, respectively, the first yaw rate Y1, the first time t1 that travels at the first yaw rate Y1, the second yaw rate Y2, and the second yaw rate. A second time t2 for traveling in Y2 is uniquely determined. Thereby, the shape of the avoidance path is uniquely determined. That is, “setting the avoidance route r _B (first avoidance route r _B1 and second avoidance route r _B2 )” means that “the lateral movement calculated based on the lateral distance between the non-continuous obstacle NCO and the white line WL”. It is synonymous with “applying the distance LD and the vehicle speed to the above four maps to determine the first yaw rate Y1, the first time t1, the second yaw rate Y2, and the second time t2.” The vehicle speed here is “the vehicle speed estimated at the point P _B (the start point of the avoidance route r _B )”. This vehicle speed can be estimated from “current vehicle speed” and “target deceleration by automatic braking control (described later)”, assuming that the current vehicle speed is maintained until a time point at which automatic braking control (described later) is executed. Hereinafter, the vehicle speed is referred to as “estimated vehicle speed” in order to distinguish it from the current vehicle speed.

In both the first and second yaw rate maps, when the vehicle speed is constant, the absolute values of the first and second yaw rates Y1 and Y2 increase as the absolute value of the lateral movement distance LD increases, and the lateral movement distance LD becomes smaller. In a fixed case, the absolute values of the first and second yaw rates Y1, Y2 are set to increase as the vehicle speed increases.
On the other hand, in both the first and second time maps, when the vehicle speed is constant, as the absolute value of the lateral movement distance LD increases, the first and second times t1 and t2 become longer and the lateral movement distance LD becomes constant. In this case, the first and second times t1 and t2 are set longer as the vehicle speed increases.

  An error based on a detection error occurs in the lateral movement distance LD and the vehicle speed. For this reason, in both the first and second yaw rate maps, even if the lateral movement distance LD and the vehicle speed change within the error range depending on the calculation cycle, the first and second yaw rates Y1 and Y2 each have a constant value. Created to maintain. The same applies to the first and second time maps.

The first device stores the avoidance route r _B (in other words, the combination of the first yaw rate Y1 and the first time t1, and the combination of the second yaw rate Y2 and the second time t2) in the RAM of the collision avoidance ECU 10. Hereinafter, the former combination is also simply referred to as (Y1, t1), and the latter combination is also simply referred to as (Y2, t2). When the TTC is equal to or less than the time threshold value Tth1 in the next calculation cycle, the first device calculates the lateral movement distance LD as described above if the forward obstacle is a non-continuous obstacle NCO. a first yaw rate Y1 and the first time t1 of the first avoidance route _{r B1} based on the vehicle speed, determining a second yaw rate Y2 for the second avoidance route _{r B2} and second time t2. The first device compares (Y1, t1) and (Y2, t2) in the current cycle with (Y1, t1) and (Y2, t2) stored in the RAM of the collision avoidance ECU 10, respectively. If it is determined that the same, determines that there is no change in the avoidance path _{r B} (i.e., stored in the RAM (Y1, t1) and (Y2, t2) does not update the.). On the other hand, in the first device, at least one of (Y1, t1) and (Y2, t2) in the current cycle is the same as (Y1, t1) and (Y2, t2) stored in the RAM of the collision avoidance ECU 10. If it is determined that there is not, the avoidance route r _B is newly set (that is, (Y1, t1) and (Y2, t2) stored in the RAM are changed to (Y1, t1) and (Y2, t2) in the current cycle. Update to).)

<Calculation of reliability>
When the avoidance route r _A or r _B is set, the first device calculates the reliability of the avoidance route r _A or r _B for each calculation cycle. Here, the reliability is a scale indicating whether or not the avoidance route r _A or r _B is a safe travel route. Since the calculation method of the reliability is the same regardless of the type of the avoidance route r _A or r _B , the calculation method of the reliability of the avoidance route r _A will be specifically described below with reference to FIG. In FIG. 8, only the grid map 60 in the vicinity of the avoidance area _RA is shown, and the continuous obstacle CO is not shown.

When the avoidance path r _A which is set by the method described above is placed on the grid map 60, the avoidance route r _A is a point 65 (point is expected to point P _{A (TTC} in the grid map 60 is time threshold Tth3) The corresponding point). On the grid map 60, the first device moves the avoidance route r _A from the point 65 to the right side in the vehicle width direction by “a length W / 2 + α1 obtained by adding a predetermined first distance α1 to the half vehicle width length W / 2”. The parallel right-side avoidance route r _AR is set, and the avoidance route r _A is set in the vehicle width direction from the point 65 by “a length W / 2 + α2 obtained by adding a predetermined second distance α2 to the half vehicle width length W / 2”. setting the left avoidance path r _AL moved parallel to the left side. The first device sets a region between the right avoidance route _{r AR} and the left avoidance path _{r AL} as avoidance regions _{R A.} That is, avoidance region R _A is, the vehicle is at least including regions a region through which the vehicle has traveled along the avoidance path r _A. The first distance α1 and the second distance α2 may be the same or different.

As described above, the unit region 62 of the grid map 60 is classified into four types of regions (obstacle region, white line region, unknown region, and safety region) having different costs. The first device, for each calculation cycle, integrating the costs of all the unit regions 62 present in avoiding region R _A, and calculates the integrated value as avoidance area cost C _A. When only a part of the unit area 62 exists in the avoidance area _RA , the unit area 62 is considered to exist in the avoidance area _RA .
The cost of the obstacle area, white line area, unknown area and safety area is C1, C2, C3 and C4 (C1>C2>C3> C4 = 0), respectively, and the obstacle area and white line area existing in the avoidance area _RA If the numbers of unknown areas and safety areas are n1, n2, n3 and n4, respectively, the avoidance area cost C _A is calculated as C _A = C1n1 + C2n2 + C3n3. In the example of FIG. 8A, there are two obstacle areas, one white line area, and three unknown areas in the avoidance area _RA . Therefore, the avoidance area cost C _A is calculated as C _A = 2C1 + C2 + 3C3. That is, avoidance region cost C _A is a measure of the risk in the case of traveling the vehicle is avoided in the region R _A along the avoidance path r _A, avoidance region cost C _A is larger the higher the risk Indicates.
For even avoidance region cost C _B avoidance region R _B of the bypass route r _B, it can be calculated in the same way.

The first device determines whether the avoidance area cost C _A or C _B is greater than or equal to a predetermined cost threshold value for each calculation cycle. When the avoidance area cost C _A or C _B is equal to or greater than a predetermined cost threshold, the first device is dangerous for the host vehicle to travel in the avoidance area R _A or R _B (in other words, the avoidance route r _A or r _B is not safe as a travel route). In this case, the avoidance route _{r A} or _{r B} in the current cycle, if the same as the avoidance path _{r A} or _{r B} are stored in the collision avoidance ECU10 of RAM, the first device, confidence in the previous period A value obtained by subtracting a predetermined value from is calculated as the reliability in the current cycle. The first device stores the initial reliability value in advance in the ROM of the collision avoidance ECU 10. For this reason, if the current cycle is the first cycle that is the first cycle in which the avoidance route r _A or r _B is set for a certain forward obstacle, the first device uses the avoidance area cost C _A or C _B as the predetermined cost. When the value is equal to or greater than the threshold, a value obtained by subtracting a predetermined value from the initial value of the reliability is calculated as the reliability in the current cycle.

On the other hand, when the avoidance area cost C _A or C _B is less than the predetermined cost threshold, the first device is safe for the host vehicle to travel in the avoidance area R _A or R _B (in other words, avoidance It determines that the route _{r a} or _{r B} is safe as a travel route). In this case, if the same as the avoidance path r _A or r _B avoided in the current cycle route r _A or r _B is stored in the RAM, the first device, the predetermined value to the reliability of the previous period The added value is calculated as the reliability in the current cycle. In addition, if the current cycle is the initial cycle, the first device, when the avoidance area cost C _A or C _B is less than a predetermined cost threshold, adds a value obtained by adding a predetermined value to the initial value of reliability. It is calculated as the reliability in the period.
That is, if the avoidance path r _A or r _B is the same over a certain period including a plurality of periods and the avoidance area cost C _A or C _B is less than the cost threshold, the avoidance path r _A Or the reliability of r _B continues to increase. On the other hand, if the avoidance path r _A or r _B is the same over a certain period including a plurality of cycles and the avoidance area cost C _A or C _B continues to be equal to or higher than the cost threshold, the avoidance path r _A Or the reliability of r _B continues to decrease.

On the other hand, the avoidance route r _A or r _B in the current cycle, if different from the avoidance path r _A or r _B are stored in the RAM, the first device resets the reliability in the operation period of the immediately preceding initial value And the calculation of the reliability of the new avoidance route r _A or r _B is started.
The first device calculates the reliability until TTC decreases and becomes equal to the time threshold value Tth3. The first device stores the reliability calculated by the above-described method in the RAM of the collision avoidance ECU 10. The reliability stored in the RAM is updated every calculation cycle.

<Automatic braking control>
In the first device, when the TTC decreases from the time threshold value Tth1 and falls below a predetermined time threshold value Tth2 (Tth3 <Tth2 <Tth1) larger than the time threshold value Tth3, there is a possibility that the host vehicle collides with a forward obstacle. It is determined that the vehicle is slightly high, and automatic braking control that automatically applies braking force to the host vehicle is executed. The time threshold value Tth2 is that “a collision avoidance with a front obstacle can be theoretically realized only by automatic braking control” and “a driver's driving operation (typically, steering wheel operation) does not interfere (in other words, The driver does not feel that the automatic braking control is an unnecessary operation) ”. This value is a value that changes according to the relative speed with respect to the front obstacle, the surrounding environment, and the like, and is set for each calculation cycle by a parameter representing the relative speed and the surrounding environment. The time threshold value Tth2 corresponds to an example of “second time threshold value”.

<Determining whether automatic steering control is performed>
Even if the automatic braking control is executed, the TTC may further decrease from the time threshold value Tth2 due to a road surface condition and / or a forward obstacle decelerating. When the TTC decreases and becomes the time threshold value Tth3 (<Tth2), the first device determines that the host vehicle is highly likely to collide with a forward obstacle, and the avoidance route r _A set by the above-described method. or determining whether the vehicle along the r _B automatically executes automatic steering control for changing the steering angle of steered wheels of the vehicle so that the vehicle travels. As described above, the first device calculates the reliability of the avoidance route r _A or r _B for each calculation cycle and updates the value until the TTC becomes equal to the time threshold value Tth3. That is, the first device calculates (updates) the reliability of the avoidance route until the timing (TTC = Tth3) for determining whether or not to execute the automatic steering control comes after the automatic braking control is started. To do.

When the TTC reaches the time threshold value Tth3, the first device determines whether the reliability of the avoidance route r _A or r _B is a predetermined reliability threshold value (whether the avoidance route r _A or r _B is safe as a travel route). It is determined whether or not it is equal to or greater than a threshold value to be determined. If the reliability of the avoidance route r _A or r _B is determined to be confidence threshold or more, it is determined that the first device, the avoidance path r _A or r _B is safe as a travel route of the vehicle. However, the first device, when the avoidance route r _A or r _B is determined to be safe travel route, does not always automatically steer the vehicle along the said avoidance path r _A or r _B .

The first device has the following three conditions in the calculation cycle where TTC = Tth3:
The reliability of the avoidance route r _A or r _B is greater than or equal to a predetermined reliability threshold value.
• Automatic control is being executed.
The braking distance based on the deceleration of the automatic braking control and the vehicle speed is longer than the distance to the front obstacle (that is, the collision with the front obstacle cannot be avoided only by the automatic braking control).
If all of the above are satisfied, it is determined that the specific condition for executing the automatic steering control is satisfied, and the host vehicle is moved so that the host vehicle travels along the avoidance route r _A or r _B set by the method described above. Automatic steering control. On the other hand, if at least one of the three conditions is not satisfied, the first device determines that the specific condition is not satisfied and does not execute the automatic steering control. In this case, the automatic braking control started when TTC ≦ Tth2 is established is continued.

As is clear from the above specific conditions, the automatic steering control is executed together with the automatic braking control. In addition, the automatic steering control is executed when it is determined that the collision with the front obstacle cannot be avoided only by the automatic braking control. In other words, if it is determined that the collision can be avoided only by the automatic braking control, even if the reliability of the avoidance route r _A or r _B is equal to or higher than the reliability threshold, the avoidance route r _A or r _B The automatic steering control along is not executed. Furthermore, even if it is determined that collision cannot be avoided only by the automatic braking control, if the reliability of the avoidance route r _A or r _B is less than the reliability threshold value, the avoidance route r _A or r _B is followed. Automatic steering control is not executed. Note that the initial value of the reliability is set lower than the reliability threshold. For this reason, when the front obstacle is a discontinuous obstacle, the reliability is not calculated when it is determined that the avoidance route r _A or r _B cannot be set because the lateral distance is less than the minimum passage length ( Therefore, the specific condition is not satisfied, and therefore the automatic steering control is not executed.

(Control flow of the first device)
Next, the control flow of the first device will be described. The CPU of the collision avoidance ECU 10 (hereinafter also simply referred to as “ECU 10”) of the first device executes the routines shown in the flowcharts of FIGS. 9A to 11B every time the computation time elapses during the engine-on period. ing.

At a predetermined timing, the CPU starts processing from step 900 in FIG. 9A and sequentially performs the following processing from step 902 to step 908.
Step 902: The CPU receives a left image signal and a right image signal from the camera sensor 11. That is, a captured image including the left image and the right image is acquired and stored in the RAM of the ECU 10.
Step 904: The CPU acquires vehicle state information (vehicle speed, longitudinal and lateral acceleration, yaw rate, turning angle, etc.) from the vehicle state sensor 12, and stores it in the RAM of the ECU 10.
Step 906: The CPU generates a parallax image from the captured image acquired in step 902 and stores it in the RAM of the ECU 10.
Step 908: As described above, the CPU selects one of the four types of areas (obstacle area, white line area, unknown area, and safety area) as the unit area 62 of the grid map 60 stored in the RAM of the ECU 10. And is stored in the RAM of the ECU 10.

Next, the CPU proceeds to step 910 and refers to the grid map 60 created in step 908 to determine whether there is an obstacle ahead in the traveling direction of the host vehicle as described above. If it is determined that no obstacle exists, the CPU makes a “No” determination at step 910 (ie, determines that there is no obstacle that can be a collision avoidance target), and proceeds to step 942 in FIG. 9B. This routine is once terminated.
On the other hand, if it is determined that there is an obstacle, the CPU determines “Yes” in step 910 (ie, determines that there is an obstacle that can be a collision avoidance target), and proceeds to the following step 912.

In step 912, the CPU calculates the TTC up to the obstacle determined to be present in the forward direction of the host vehicle in step 910, and determines whether the TTC is equal to or less than the time threshold value Tth0. The time threshold value Tth0 is a threshold value that determines whether or not to call attention. If it is determined that TTC ≦ Tth0 does not hold (that is, TTC> Tth0), the CPU determines “No” in step 912 (that is, the possibility of collision with a front obstacle is extremely low, and alerts are issued. It is determined that the timing has not yet arrived), the process proceeds to step 942 in FIG. 9B, and this routine is temporarily terminated.
On the other hand, if it is determined that TTC ≦ Tth0 is established, the CPU determines “Yes” in step 912 (ie, determines that there is a possibility of colliding with a front obstacle), and proceeds to the following step 914.

In step 914, the CPU determines whether or not the TTC to the front obstacle is equal to or less than the time threshold value Tth1. The time threshold value Tth1 is a threshold value for determining whether to start setting the avoidance route r _A or r _B. TTC ≦ Tth1 is not satisfied (i.e., TTC> Tth1) When it is determined that, CPU determines "No" at step 914 (i.e., timing for starting the setting of the avoidance path _{r A} or _{r B} are still arriving It is determined that it is not) and the processing of the following step 916 is performed.

  Step 916: The CPU generates a warning request signal for the front obstacle, and transmits the signal to the alarm ECU 50. As a result, the buzzer 51 alerts the driver. That is, the process of step 916 is performed when TTC satisfies Tth1 <TTC ≦ Tth0.

On the other hand, if it is determined in step 914 that TTC ≦ Tth1 is established, the CPU determines “Yes” in step 914 (that is, the timing for starting to set the avoidance route r _A or r _B has arrived). And proceed to step 922 below.

In step 922, CPU starts setting the avoidance path _{r A} or _{r B.} Upon setting the avoidance path r _A or r _B, CPU determines whether the front obstacle has continuity. Specifically, the CPU calculates a line segment 82 by linearly approximating the connected area 80 including the obstacle area where the forward obstacle exists in the grid map 60. And it is determined whether the length of the line segment 82 is more than a length threshold value. If it is determined that the length is equal to or greater than the length threshold, the CPU determines that the front obstacle is a continuous obstacle CO having continuity, determines “Yes” in step 922, and proceeds to step 924 below.

  In the routine of FIG. 9A, the CPU executes the routine shown in the flowchart of FIG. When the CPU proceeds to step 924, the CPU starts processing from step 1000 in FIG. 10, and sequentially performs the processing of step 1002 and step 1004 described below.

Step 1002: The CPU calculates an inclination g of “a line segment 82 obtained by linear approximation of the connection region 80” calculated in Step 922, and stores it in the RAM of the ECU 10.
Step 1004: The CPU adds the slope g calculated in Step 1002 to the yaw rate map and time map stored in advance in the ROM of the ECU 10, and the vehicle speed and target deceleration acquired in Step 904 in FIG. 9A. The estimated vehicle speed calculated based on the above is applied to determine the yaw rate Y and time t.

Next, the CPU proceeds to step 1006 to determine whether or not the current calculation cycle (hereinafter also simply referred to as “cycle”) is the initial cycle. Here, the initial period is a period in which the avoidance route r _A or r _B for a certain forward obstacle is set for the first time. In other words, it is a cycle in which it was determined that TTC ≦ Tth1 was established for the first time with respect to TTC up to a certain forward obstacle. If it is determined that the current cycle is the first cycle, the CPU determines “Yes” in step 1006 (that is, the avoidance route r _A is set based on (Y, t) determined in step 1004). And the following processing of step 1008 and step 1010 is performed.

Step 1008: The CPU sets the avoidance area _RA on the grid map 60 as described above based on (Y, t) determined in step 1004 in the current cycle. The CPU stores the (Y, t) and the shape of the avoidance area _RA in the RAM of the ECU 10.
Step 1010: CPU, for avoidance region _{R A} set in step 1008, calculates the avoidance area cost _{C A} in the manner described above, is stored in ECU10 of RAM.

Then, CPU proceeds to step 1012, avoidance region cost _{C A} calculated in step 1010 is equal to or more than the cost threshold. If avoidance region cost C _A is equal to or more than the cost threshold, CPU makes a "Yes" determination at step 1012 (i.e., it is dangerous to travel the vehicle is avoided in the region R _A determination And the following step 1014 is performed.

Step 1014: The CPU calculates the reliability of the avoidance route r _A in the current cycle. Specifically, the CPU calculates the reliability as a value obtained by subtracting a predetermined value from an initial value stored in advance in the ROM of the ECU 10. The CPU stores the reliability in the RAM of the ECU 10, and then proceeds to step 928 (described later) in FIG. 9A via step 1030.

On the other hand, if it is determined that the avoidance region cost _{C A} in step 1012 is less than the cost threshold, CPU makes a "No" determination at step 1012 (i.e., to travel a vehicle avoidance region _{R A} Is determined to be safe), and the processing of the following step 1016 is performed.

Step 1016: The CPU calculates the reliability of the avoidance route r _A in the current cycle. Specifically, the CPU calculates the reliability as a value obtained by adding a predetermined value to an initial value stored in advance in the ROM of the ECU 10. The CPU stores the reliability in the RAM of the ECU 10, and then proceeds to step 928 (described later) in FIG. 9A via step 1030.

  On the other hand, if it is determined in step 1006 that the current cycle is not the initial cycle, the CPU determines “No” in step 1006 and proceeds to the following step 1018.

In step 1018, the CPU determines whether (Y, t) determined in step 1004 in the current cycle is the same as (Y, t) stored in the RAM. If it is determined that they are the same, the CPU determines “Yes” in step 1018 (that is, determines that the avoidance route r _A and the avoidance region _RA are not changed from the immediately preceding cycle), and is stored in the RAM. (Y, t) is not changed. Thereafter, the CPU performs the following step 1020.

Step 1020: CPU is avoidance region _{R A} (i.e., avoidance region _{R A} set in step 1008 in the previous cycle) stored in the ECU10 in the RAM for the avoidance area cost _{C A} in the manner described above Calculate and store in the RAM of the ECU 10. The calculation of the avoidance region cost C _A is performed on the grid map 60 created in step 908 (see FIG. 9A) in the current cycle.

Then, CPU proceeds to step 1022, avoidance region cost _{C A} calculated in step 1020 is equal to or more than the cost threshold. If avoidance region cost C _A is equal to or more than the cost threshold, CPU makes a "Yes" determination at step 1022 (i.e., it is dangerous to travel the vehicle is avoided in the region R _A determination Then, the following processing of step 1024 is performed.

Step 1024: The CPU calculates the reliability of the avoidance route r _A in the current cycle. Specifically, the CPU calculates the reliability as a value obtained by subtracting a predetermined value from the reliability in the immediately preceding cycle. The reliability is stored in the RAM of the ECU 10. The CPU stores the reliability in the RAM of the ECU 10, and then proceeds to step 928 (described later) in FIG. 9A via step 1030.

On the other hand, if it is determined that the avoidance region cost _{C A} in step 1022 is less than the cost threshold, CPU makes a "No" determination at step 1022 (i.e., to travel a vehicle avoidance region _{R A} Is determined to be safe), and the processing of the following step 1026 is performed.

Step 1026: The CPU calculates the reliability of the avoidance route r _A in the current cycle. Specifically, the CPU calculates the reliability as a value obtained by adding a predetermined value to the reliability in the immediately preceding cycle. The CPU stores the reliability in the RAM of the ECU 10, and then proceeds to step 928 (described later) in FIG. 9A via step 1030.

On the other hand, when it is determined in step 1018 that (Y, t) determined in step 1004 in the current cycle is not the same as (Y, t) stored in the RAM, the CPU In Step 1018, it is determined as “No” (that is, it is determined that the avoidance route r _A has been changed from the immediately preceding cycle), and the following Step 1028 is performed.

  Step 1028: The CPU resets the reliability stored in the RAM (that is, the reliability calculated in the immediately preceding cycle) to return to the initial value. Thereafter, the CPU executes the processing after step 1008 described above. When the processing of step 1008 is performed after step 1028, the CPU updates (Y, t) stored in the RAM to (Y, t) determined in step 1004 in the current cycle. To do.

  On the other hand, when it is determined in step 922 in FIG. 9A that the length of the line segment 82 obtained by linearly approximating the connection region 80 is less than the length threshold, the CPU determines that the front obstacle has continuity. It is determined that the non-continuous obstacle NCO does not exist, “No” is determined in Step 922, and the process proceeds to Step 926 below.

  In the routine of FIG. 9A, in step 926, the CPU executes the routine shown in the flowcharts of FIGS. 11A and 11B. When the CPU proceeds to step 926, the CPU starts processing from step 1100 of FIG. 11A and performs processing of step 1102 described below.

Step 1102: As described above, the CPU determines the right lateral distance D _R (positive value), which is the lateral distance between the front obstacle (the right end thereof) and the right white line RWL (the left end thereof), and the front obstacle (of the The left lateral distance D _L (negative value), which is the lateral distance between the left end) and the left white line LWL (the right end thereof) is calculated and stored in the RAM of the ECU 10.

Then, CPU proceeds to step 1104, determines a right transverse distance D _R, compares the absolute value of the left transverse distance D _L, a, whether the larger value is the minimum passage length or longer. If it is determined that the larger value is less than the minimum passage length, the CPU makes a “No” determination at step 1104 (that is, the avoidance route r _B passing between the front obstacle and the white line WL is It is determined that setting is impossible), and the process proceeds to step 928 in FIG. 9A (described later).
On the other hand, if it is determined that the larger value is greater than or equal to the minimum passage length, the CPU determines “Yes” in step 1104 (that is, the avoidance route r passing between the front obstacle and the white line WL). _B is determined to be settable), and the following processing of Step 1106 and Step 1108 is performed.

Step 1106: The CPU calculates the lateral movement distance LD of the host vehicle as described above based on the larger lateral distance and stores it in the RAM of the ECU 10.
Step 1108: The CPU adds the lateral movement distance LD calculated in Step 1106 to each of the first and second yaw rate maps and the first and second time maps stored in advance in the ROM of the ECU 10, and FIG. 9A. The first yaw rate Y1, the first time t1, the second yaw rate Y2, and the second time t2 are determined by applying the vehicle speed acquired in step 904 and the estimated vehicle speed calculated based on the target deceleration.

  Next, the CPU proceeds to step 1110 to determine whether or not the current cycle is the initial cycle. If it is determined that the current cycle is the first cycle, the CPU determines “Yes” in step 1110 and performs the following steps 1112 and 1114 (see FIG. 11B).

Step 1112: CPU, based on the determined at step 1108 in the current cycle (Y1, t1) and (Y2, t2), in the manner described above to set an avoidance region _{R B} on the grid map. The CPU, with the (Y1, t1) and (Y2, t2), the shape of the avoidance region _{R B,} and stores the ECU10 of RAM.
Step 1114: CPU, for avoidance region _{R B} set in step 1112, as described above to calculate the avoidance area cost _{C B,} is stored in ECU10 of RAM.

Then, CPU proceeds to step 1116, the avoidance region cost _{C B} calculated in step 1114 is equal to or larger cost threshold. If avoidance region cost C _B is equal to or more than the cost threshold, CPU makes a "Yes" determination at step 1116 (i.e., it is dangerous to travel the vehicle is avoided in the region R _B determination Then, the following step 1118 is performed.

Step 1118: The CPU performs the same process as step 1014 in FIG. 10, and calculates the reliability of the avoidance route r _B in the current cycle. Thereafter, the CPU proceeds to step 928 (described later) in FIG. 9A via step 1134.

On the other hand, if it is determined that at step 1116 is avoidance region cost _{C B} is less than the cost threshold, CPU makes a "No" determination at step 1116 (i.e., to travel the vehicle is avoided in the region _{R B} Is determined to be safe), and the following step 1120 is performed.

Step 1120: The CPU performs the same processing as step 1016 in FIG. 10 to calculate the reliability of the avoidance route r _B in the current cycle. Thereafter, the CPU proceeds to step 928 (described later) in FIG. 9A via step 1134.

  On the other hand, if it is determined in step 1110 (see FIG. 11A) that the current cycle is not the initial cycle, the CPU determines “No” in step 1110 and proceeds to step 1122 below.

In step 1122, the CPU determines that (Y1, t1) and (Y2, t2) determined in step 1108 in the current cycle are the same as (Y1, t1) and (Y2, t2) stored in the RAM. It is determined whether or not. If it is determined that the same, CPU makes a "Yes" determination at step 1122 (i.e., avoidance route _{r B} and avoidance region _{R B} determines that no change from the previous period) is stored in the RAM (Y1, t1) and (Y2, t2) are not changed. Thereafter, the CPU performs the processing of the following step 1124 (see FIG. 11B).

Step 1124: The CPU calculates the avoidance region cost C _B as described above for the avoidance region R _B stored in the RAM of the ECU 10 (that is, the avoidance region R _B set in step 1112 in the previous cycle). Calculate and store in the RAM of the ECU 10. The calculation of the avoidance region cost C _B is performed on the grid map 60 created in step 908 (see FIG. 9A) in the current cycle.

Then, CPU proceeds to step 1126, the avoidance region cost _{C B} calculated in step 1124 is equal to or larger cost threshold. If avoidance region cost C _B is equal to or more than the cost threshold, CPU makes a "Yes" determination at step 1126 (i.e., it is dangerous to travel the vehicle is avoided in the region R _B determination Then, the following processing of step 1128 is performed.

Step 1128: The CPU performs the same process as step 1024 in FIG. 10, and calculates the reliability of the avoidance route r _B in the current cycle. Thereafter, the CPU proceeds to step 928 (described later) in FIG. 9A via step 1134.

On the other hand, when it is determined in step 1126 that the avoidance area cost C _B is less than the cost threshold, the CPU determines “No” in step 1126 (that is, the host vehicle travels in the avoidance area R _B. Is determined to be safe), and the following processing in step 1130 is performed.

Step 1130: The CPU calculates the reliability of the avoidance route r _B in the current cycle by performing the same process as in step 1026 of FIG. Thereafter, the CPU proceeds to step 928 (described later) in FIG. 9A via step 1134.

In contrast, in step 1122 (see FIG. 11A), (Y1, t1) and (Y2, t2) determined in step 1108 in the current cycle are stored in the RAM (Y1, t1) and When determining that it is not the same as (Y2, t2), the CPU determines “No” in step 1122 (that is, determines that the avoidance route r _B has been changed from the immediately preceding cycle), and the following step 1132 is performed. Perform the process.

  Step 1132: The CPU resets the reliability stored in the RAM (that is, the reliability calculated in the immediately preceding cycle) to return to the initial value. Thereafter, the CPU executes the processing after step 1112 described above. When the processing of step 1112 is performed after step 1132, the CPU determines (Y1, t1) and (Y2, t2) stored in the RAM in step 1108 in the current cycle ( Y1, t1) and (Y2, t2).

  When the processing of step 1014, step 1016, step 1024, and step 1026 in FIG. 10 is completed, the processing of step 1118, step 1120, step 1128, and step 1130 of FIG. 11B is completed, or step 1104 of FIG. When the determination is “No”, the CPU proceeds to step 928 in FIG. 9A.

  In step 928, the CPU determines whether or not the TTC to the front obstacle is equal to or less than the time threshold value Tth2. The time threshold value Tth2 is a threshold value that determines whether or not to start automatic braking control. If it is determined that TTC ≦ Tth2 is not satisfied (that is, TTC> Tth2), the CPU determines “No” in step 928 (that is, determines that the timing for starting the automatic braking control has not yet arrived). ), The process proceeds to step 942 in FIG. 9B, and this routine is temporarily terminated.

  On the other hand, if it is determined that TTC ≦ Tth2 is established, the CPU determines “Yes” in step 928 (that is, determines that the timing for starting automatic braking control has arrived), and performs the processing in step 930 below. Do.

  Step 930: The CPU calculates the automatic braking control amount necessary for avoiding the collision with the front obstacle based on the vehicle state information acquired in step 904, and includes the signal representing the control amount. A request signal is generated, and the signal is transmitted to the brake ECU 20. As a result, the brake actuator 22 is driven to adjust the acceleration of the host vehicle. That is, automatic braking control is executed. Thereafter, the CPU proceeds to step 932 in FIG. 9B.

  In step 932, the CPU determines whether or not the TTC to the front obstacle is equal to the time threshold value Tth3. The time threshold value Tth3 is a threshold value that determines whether or not the timing for determining whether or not to execute the automatic steering control has arrived. When it is determined that TTC = Tth3 is not satisfied (that is, TTC> Tth3), the CPU determines “No” in step 932 (that is, the timing for determining whether or not to execute the automatic steering control has yet arrived). 9), the process proceeds to step 942 in FIG. 9B to end the present routine tentatively.

  On the other hand, if it is determined that TTC = Tth3 is established, the CPU determines “Yes” in step 932 (determines that the timing for determining whether or not to execute automatic steering control has arrived), and the following steps: Proceed to 934.

In step 934, the CPU performs the following three conditions:
The reliability of the avoidance route r _A or r _B calculated in the current cycle is greater than or equal to a predetermined reliability threshold.
The automatic control control that has been executed by the processing of Step 930 is continued.
-The braking distance based on the deceleration of the automatic braking control and the vehicle speed is longer than the distance to the front obstacle.
It is determined whether or not a specific condition that all of the above are satisfied is satisfied. When it is determined that the specific condition is satisfied, the CPU determines “Yes” in step 934 (that is, determines that the condition necessary for executing the automatic steering control is satisfied), and the following step 936 Process.

Step 936: When the forward obstacle is a continuous obstacle CO, the CPU follows the avoidance path r _A set by (Y, t) stored in the RAM, while the forward obstacle is a non-continuous obstacle. In the case of an object NCO, the automatic steering control amount necessary for the host vehicle to travel along the avoidance route r _B set by (Y1, t1) and (Y2, t2) stored in the RAM is calculated. To do. The CPU generates an automatic steering request signal including a signal representing the control amount, and transmits the signal to the steering ECU 40. As a result, the motor driver 41 is controlled and torque is generated in the steering motor 42, whereby steering assist torque is applied or the left and right steering wheels are steered. That is, automatic steering control is executed. Thereafter, the CPU performs a process of step 940 described later.

  On the other hand, when it is determined in step 934 that the specific condition is not satisfied, the CPU determines “No” in step 934 (that is, it is determined that the condition necessary for executing the automatic steering control is not satisfied). Then, the following process of step 938 is performed.

  Step 938: The CPU does not calculate the automatic steering control amount. For this reason, automatic steering control is not executed. Thereafter, the CPU performs the process of step 940 below.

Step 940: The CPU resets the grid map 60 and the reliability stored in the RAM of the ECU 10. In addition, CPU is stored in ECU10 of RAM (Y, t) or (Y1, t1) and (Y2, t2) and the shape of the avoidance region _{R A} or _{R B,} avoidance region cost _{C A} or Delete C _B. Thereafter, the CPU proceeds to step 942 to end the present routine tentatively.

The effects of the first device will be described. According to the first device, each unit area 62 of the grid map 60 is identified not only as to whether it is an obstacle area, but also as to whether it is an unknown area. Here, the unknown area is an area where it is unknown whether the host vehicle can safely travel, and typically represents an area where a depression or an inclined surface is formed. For this reason, the avoidance area cost C _A or C _B is not limited to the number n1 of obstacle areas existing in the avoidance area R _A or R _B and the cost C1 (that is, the product of both), but also the avoidance area R _A or R It is also calculated based on the number n3 of unknown regions existing in _B and the cost C3 (that is, the product of both). When the avoidance area cost C _A or C _B is equal to or higher than the cost threshold, the reliability is calculated as a value obtained by subtracting a predetermined value from the reliability of the immediately preceding calculation cycle, and the avoidance area cost C _A or C _B is the cost threshold. In the case of less than, it is calculated as a value obtained by adding a predetermined value to the reliability of the immediately preceding calculation cycle.

According to this configuration, the reliability of the avoidance route r _A or r _B reflects not only the number and cost of obstacle regions but also the number and cost of unknown regions. In addition, the cost C1 of the obstacle area is set higher than the cost C3 of the unknown area. The obstacle area has a higher degree of risk as a travel route of the vehicle than the unknown area. For this reason, the number of unknown areas and the cost are also reflected in the reliability of the avoidance route r _A or r _B , and the avoidance area r is set by setting the magnitude relationship between the cost of the obstacle area and the unknown area as C1> C3. _The avoidance area cost C _A or C _B that more accurately reflects the risk level of _A or r _B can be calculated. That is, the reliability that more accurately reflects the safety level of the avoidance route r _A or r _B can be calculated. As a result, it can be accurately determined whether or not the avoidance route r _A or r _B is a safe travel route.

In particular, in the first device, each unit area 62 of the grid map 60 is not only specified as to whether it is an obstacle area or an unknown area, but is also specified as to whether it is a white line area or a safety area. For this reason, the avoidance area cost C _A or C _B is calculated as a value that more accurately reflects the risk of the avoidance area r _A or r _B , and the reliability further increases the safety degree of the avoidance path r _A or r _B. Calculated as an accurately reflected value. As a result, it is possible to more accurately determine whether or not the avoidance route r _A or r _B is a safe travel route.

In general, an obstacle is detected using a radar sensor, a camera sensor, or the like. However, depending on weather conditions or environmental conditions, the presence or absence of an obstacle may be erroneously determined. That is, there is a possibility that it is determined that the obstacle is present but not present, or that the obstacle is present although the obstacle is not present. For this reason, in the structure which determines the presence or absence of an obstruction for every calculation period, there exists a possibility of misjudging the presence or absence of an obstruction. As a result, when it is determined that an obstacle does not exist in a certain calculation cycle even though an obstacle actually exists on the avoidance route, the avoidance route is determined to be a safe travel route. The determination accuracy may be reduced. On the other hand, according to the first device, the reliability is calculated based on the avoidance area cost C _A or C _B calculated for each calculation cycle in the period from the time threshold Tth1 to the time threshold Tth3 ( Therefore, even if the presence / absence of an obstacle is erroneously determined in a certain calculation cycle of the period, the influence of the erroneous determination on the accuracy of reliability can be reduced. For this reason, it is possible to more accurately determine whether or not the avoidance route r _A or r _B is a safe travel route.

(Modification)
Next, a collision avoidance control device (hereinafter also referred to as a first deformation device) according to a modification of the first embodiment of the present invention will be described. The first deformation device is different from the first device in that a plurality of avoidance paths are set for each calculation cycle when the front obstacle is a continuous obstacle CO or a non-continuous obstacle NCO.

First, a case where the front obstacle is a continuous obstacle CO will be described. Avoidance path r _A set in the first embodiment _(i.e., (Y, combinations path having a t)) k th time counted when called reference avoidance route r _A and the order of proximity to the reference avoidance route r _A The avoidance route r _{A —} k (k is an integer equal to or greater than 0) is set as a route having a combination of (Y + ΔY · k, t) when the yaw rate Y of the reference avoidance route r _A is positive, and the reference avoidance route r _When the yaw rate Y of _A is negative, a route having a combination of (Y−ΔY · k, t) is set. Here, ΔY is a preset positive yaw rate. That is, when the yaw rate Y of the reference avoidance path r _A is positive, the plurality of avoidance paths r _A are set by sequentially adding a predetermined yaw rate ΔY to the yaw rate Y, while the yaw rate of the reference avoidance path r _A When Y is negative, it is set by sequentially subtracting a predetermined yaw rate ΔY from the yaw rate Y.

The first modification device assigns an ID for identifying each avoidance route r _{A —} k (that is, each combination of yaw rate and time), and associates each avoidance route r _{A —} k and each reliability with the ID. It stores in RAM of collision avoidance ECU10. The first transformation device, if you set the following plurality of avoidance route r _A _k in the manner described above in the calculation cycle, the yaw rate of the avoidance route r _A _k, each avoidance path r _A _k stored in RAM Compare with yaw rate. Then, if the value of the yaw rate is determined to be identical, the first modified apparatus determines that there is no change to the avoidance path r _A _k, the ID of the avoidance path r _A _k in the previous period in the next cycle take over. That is, the reliability in the next cycle is calculated based on the reliability calculated in the immediately preceding cycle. On the other hand, if it is determined that the values of the yaw rates are different, the first deformation device determines that the avoidance route r _{A —} k has been changed, resets the ID of the avoidance route r _{A —} k in the immediately preceding cycle, and sets a new ID. The given avoidance route r _{A —} k is set. That is, the reliability calculated in the immediately preceding cycle is reset, and the reliability in the next cycle is calculated based on the initial value. The first deformation device determines whether or not a specific condition is satisfied for the avoidance route r _{A —} k having the highest reliability at the time when TTC = Tth3. performing an automatic steering control along the _a _k.

Next, the case where the front obstacle is a discontinuous obstacle NCO will be described. Bypass route _{r B} set in the first embodiment (i.e., (Y1, t1) and (Y2, t2) combined route with the) When referred to the reference bypass route _{r B} a, in order of proximity to the reference bypass route _{r B} The k-th avoidance route r _{B —} k (k is an integer of 0 or more) when counted is a route having a combination of (LD + ΔLD · k, t) when the lateral movement distance LD of the reference avoidance route r _B is positive. When the lateral movement distance LD of the reference avoidance route r _B is negative, the route is set as a route having a combination of (LD−ΔLD · k, t). Here, ΔLD is a preset positive lateral movement distance. That is, the plurality of avoidance paths r _B are set by sequentially adding a predetermined lateral movement distance ΔLD to the lateral movement distance LD when the lateral movement distance LD of the reference avoidance path r _B is positive. When the lateral movement distance LD of the avoidance route r _B is negative, the distance is set by sequentially subtracting a predetermined lateral movement distance ΔLD from the lateral movement distance LD. The range of k is set so that “LD + ΔLD · k” and “LD−ΔLD · k” do not allow the host vehicle to get over the white line.

The first modification device also assigns an ID for identifying each avoidance route r _{B —} k to each other. The method for determining whether to take over the avoidance path r _{B —} k in the immediately preceding cycle in the next calculation cycle is the same as that in the case where the front obstacle is the continuous obstacle CO, and thus description thereof is omitted.

Also with this configuration, the same effects as the first device can be achieved. In addition, according to the configuration of the first deformation device, a plurality of avoidance routes r _A or r _B are set, and whether or not a specific condition is satisfied is determined for the avoidance route having the highest reliability among them. Therefore, in comparison with only a set structure one avoidance path r _A or r _B, safety of the avoidance route r _A or r _B is further increased, further improving the reliability of the own degree steering control .

(Second Embodiment)
Next, a collision avoidance control device (hereinafter also referred to as “second device”) according to a second embodiment of the present invention will be described. The second device is different from the first device in the method of determining whether the avoidance route r _A or r _B is safe as a travel route. Since this method is the same regardless of the type of avoidance route r _A or r _B , a method for determining whether or not avoidance route r _A is safe as a travel route will be described below with reference to FIG. explain.

FIG. 12 shows an avoidance route r _A and an avoidance region R _A set on the grid map 160 when the front obstacle is a continuous obstacle CO (shown as a connection region 80 in FIG. 12). In FIG. 12, only the grid map 160 in the vicinity of the avoidance region _RA is illustrated. The unit area 162 of the grid map 160 is specified as one of three areas: an obstacle area, an unknown area, and a safety area. That is, in the second device, the unit area 162 is not specified as a white line area. The type of the unit area 162 is specified based on the parallax information and the pixel information. However, there is a case where noise is included in these pieces of information, and there is a case where the type of region is erroneously specified due to the noise. Since the parallax information and the pixel information at positions away from the host vehicle are more likely to contain noise, the probability that the type of the unit area 162 is erroneously specified increases as the distance from the host vehicle increases. In other words, the reliability of the cost for each type of the unit area 162 decreases as the distance from the host vehicle increases.

Therefore, in the second device, a grid map 160, from the avoidance path _{r A} starting point is a point 165, a plurality of compartments for each predetermined distance (in the example of FIG. 12, the three sections of D1, D2 and D3) The cost value is changed for each section. Specifically, the value of the cost C1 of the obstacle area is set to be higher as the section is closer to the host vehicle. That is, if the cost C1 of the obstacle region in the sections D1, D2, and D3 is defined as C11, C12, and C13, respectively, the magnitude relationship between them is expressed as C11>C12> C13. Similarly, the value of the cost C3 of the unknown area is set to be higher as the section is closer to the host vehicle. If the cost C3 of the unknown area in the sections D1, D2, and D3 is defined as C31, C32, and C33, respectively, these magnitude relationships are expressed as C31>C32> C33.

  In addition, in the same section, since the obstacle area has a higher risk as a travel route than the unknown area, the cost C1 of the obstacle area is set higher than the cost C3 of the unknown area. That is, C11> C31, C12> C32, and C13> C33 are satisfied. In other words, when the distance from the own vehicle to the obstacle area and the distance from the own vehicle to the unknown area are substantially the same, the cost C1 of the obstacle area is set higher than the cost C3 of the unknown area. Note that the cost C4 of the safety area is 0 regardless of the section.

The second device calculates six costs (first cost to sixth cost) to be described later, and avoids when each cost is less than a preset cost threshold value (first cost threshold value to sixth cost threshold value). determines that the route r _a is safe as a travel path, it determines that at least one of the first cost to sixth costs but not less than the cost threshold, avoidance route r _a is not safe as the travel path. Hereinafter, each cost will be specifically described.

(First cost C _C1 )
The second device determines the presence or absence of an obstacle area for each section. When the second device determines that one or more obstacle areas exist in a certain section, the second apparatus determines that there are obstacle areas in the section, and determines that no obstacle area exists in the certain section. In such a case, it is determined that there is no obstacle area in the section. The second device extracts the sections for which it is determined that the obstacle area exists, and the cost of each section is set to the number of obstacle areas per one section regardless of the number of obstacle areas in the section. Calculate as cost. Then, the extracted value obtained by summing the respective cost of compartments is calculated as first cost C _C1 avoidance region RA.
In the example of FIG. 12, the number of obstacle areas in the sections D1, D2, and D3 is 0, 2, and 1, respectively. For this reason, the second device calculates a value obtained by adding the costs C12 and C13 of the obstacle area per section D2 and section D3 as the first cost C _C1 of the avoidance area RA (C _C1 = C12 + C13). .

(Second cost C _n1 )
The second device calculates the number of obstacle areas in the avoidance area _RA for each section, and calculates the number of obstacle areas in the sections D1, D2, and D3 as the second cost of the section D1 in the avoidance area _RA. C _n11 , the second cost C _n12 of the section D2, and the second cost C _n13 of the section D3 are calculated. That is, the second cost C _n1 is calculated by the number equal to the number of sections. In the example of FIG. 12, the second cost C _n11 = 0, the second cost C _n12 = 2 and the second cost C _n13 = 1.

(Third cost C _n1total )
The second device, the cost obtained by summing the second cost _{C n1} in each section is calculated as a third cost _{C N1total} avoidance region _{R A.} In the example of FIG. 12, the third cost C _n1total is 0 + 2 + 1 = 3.

(Fourth cost C _C3 )
The second device determines the presence or absence of an unknown area for each section. When the second device determines that one or more unknown areas exist in a certain partition, determines that there is an unknown area in the partition, and determines that no unknown area exists in a certain partition, It is determined that there is no unknown area in the section. The second device extracts a section determined to have an unknown area, and calculates the cost of each section as the cost of the unknown area per one section regardless of the number of unknown areas in the section. To do. Then, a value obtained by adding the respective costs of the extracted sections is calculated as the fourth cost C _C3 of the avoidance region _RA . In the example of FIG. 12, the numbers of unknown regions in the sections D1, D2, and D3 are 2, 2, and 0, respectively. For this reason, the second device calculates the sum of the costs C31 and C32 of the unknown area per section D1 and section D2 as the first cost C _C3 of the avoidance area _RA (C _C3 = C31 + C32). .

(Fifth cost C _n3 )
The second device, the number of unknown regions within avoidance region _{R A} calculated for each partition, partition D1, the number of each of the unknown region of D2 and D3, the fifth cost avoidance region _R Lot _A D1 _{C n31} It is calculated as the fifth cost _{C n33} fifth cost _{C n32} and partition D3 compartments D2. That is, the fifth cost C _n3 is calculated by the number equal to the number of sections. In the example of FIG. 12, fifth cost _{C n31} = 2, the fifth cost _{C n32} = 2, is a fifth cost _{C n33} = 0.

(6th cost C _n3total )
The second device, the cost of the sum of the fifth cost _{C n3} in each section is calculated as the sixth cost _{C N3total} avoidance region _{R A.} In the example of FIG. 12, the sixth cost C _n3total is 2 + 2 + 0 = 4.

A cost threshold value (first cost threshold value to sixth cost threshold value) is set in advance for each of the six costs (first cost C _{C1 to} sixth cost C _n3total ). More specifically, cost thresholds are set for the second cost C _n1 and the fifth cost C _{n3 by} the number of partitions. The cost threshold value for each section is set to increase as the distance from the host vehicle increases.
The second device determines whether each of the six costs is less than the corresponding cost threshold. If all six cost is determined to be less than the corresponding cost threshold, it determines that the second apparatus, the avoidance route r _A is safe as a travel route. In this case, the avoidance route r _A in the current cycle, if the same avoidance path r _A stored in the RAM of the collision avoidance ECU, the second device, if the reliability (first cycle in the immediately preceding cycle A value obtained by adding a predetermined value to the initial value is calculated as the reliability in the current cycle.

On the other hand, if at least one of the six cost determined to be equal to or greater than the corresponding cost threshold, the second device, the avoidance route r _A is determined to be unsafe as a travel route. Given this case, if the same as the avoidance path r _A avoidance route r _A in the current cycle is stored in the RAM, the second device, the confidence in the previous period (initial value if the initial period) The value obtained by subtracting the value of is calculated as the reliability in the current cycle.
The magnitude of the predetermined value (subtraction value) to be subtracted may differ depending on which of the first cost C _{C1 to} the sixth cost C _n3total is _{equal to} or higher than the cost threshold. For example, the magnitude of the subtraction value when the first cost C _C1 is greater than or equal to the first cost threshold may be greater than the magnitude of the subtraction value when the third cost C _C3 is greater than or equal to the third cost threshold.

For even bypass route r _B, whether it is safe as a travel route in the above same method is determined.

Also with this configuration, the same effects as the first device can be achieved. In addition, in the second apparatus, the grid map 160 are divided into a plurality of sections from the bypass route r _A starting point is a point 165 for each predetermined distance. The value of the cost C1 of the obstacle area and the value of the cost C3 of the unknown area are both set to be lower as the section is further away from the host vehicle. For this reason, even if there is a high possibility that the obstacle area and the unknown area will be erroneously specified due to the noise included in the parallax information and the pixel information in the section separated from the host vehicle, The possibility that the first cost C _C1 and the fourth cost C _C3 are increased can be reduced. In addition, the threshold value for the number of obstacle areas and the threshold value for the number of unknown areas for each section are larger as the section is further away from the own vehicle (that is, the obstacle area and the unknown area are more separated from the own vehicle). Even if the number is large, the possibility of being over the cost threshold is reduced.) For this reason, even if there is a high possibility that the obstacle area and the unknown area are erroneously specified in the section separated from the host vehicle, the second cost C _n1 and the fifth cost C _n3 are caused to be the cost threshold value due to the erroneous specification. The possibility of becoming the above can be reduced. Therefore, according to said structure, the collision avoidance control apparatus with which the robustness was ensured is realizable.

  As mentioned above, although the vehicle control apparatus which concerns on embodiment of this invention was demonstrated, this invention is not limited to these, A various change is possible unless it deviates from the objective of this invention.

  For example, the time thresholds Tth0, Tth1, Tth2, and Tth3 may all be equal (Tth0 = Tth1 = Tth2 = Tth3), or some of them may be equal (for example, Tth1 = Tth2).

In addition, also in the first embodiment, it may be separated into a plurality of sections 65 that it is the starting point of the avoidance path r _A or r _B a grid map 60 for each predetermined distance. The values of the cost C1 for the obstacle area, the cost C2 for the white line area, and the cost C3 for the unknown area may be set so as to decrease for each section as the distance from the host vehicle increases. Also with this configuration, it is possible to realize a collision avoidance control device that ensures robustness.

Furthermore, in general, a shadow is easily formed in front of the front obstacle (on the own vehicle side). A unit area where a shadow exists is easily specified as an unknown area. For this reason, if there is a shadow in the unit area in front of the front obstacle, even if the unit area is a safe travel route, there is a high possibility that the unit area is identified as an unknown area rather than a safe area. Accordingly, when the front of the unit area of the front obstacle in the second embodiment is included in avoidable range R _A or in R _B, if the unit area is identified as an unknown region (see FIG. 12), the The cost C2 of the unknown area may be set lower than the cost C2 of the normal unknown area in the same section. According to this configuration, there is a possibility that the value of the fourth cost C _C3 is increased due to the fact that the shadow is present and the region is erroneously specified as the unknown region because it is actually a safe region. Therefore, a collision avoidance control device that can ensure robustness can be realized.

Furthermore, in the second embodiment, the grid map 160 is partitioned into a plurality of sections starting from the point 165 that is the starting point of the avoidance route r _A or r _B , but the way of partitioning is not limited to this configuration. For example, a plurality of sections may be formed by dividing a grid map at predetermined distances starting from an obstacle area where a forward obstacle exists.

  Further, the predetermined value to be added to or subtracted from the reliability (or the initial value of reliability) in the immediately preceding calculation cycle may be variable depending on the TTC. Since the accuracy of specifying whether or not the vehicle is in the obstacle area increases as the host vehicle approaches the obstacle area, the predetermined value is used when the TTC is large (that is, when the distance to the front obstacle is long). A configuration in which the predetermined value is set higher and the predetermined value is set higher as the TTC becomes smaller (that is, as the distance to the front obstacle becomes shorter) may be adopted.

10: collision avoidance ECU, 11: camera sensor, 12: vehicle state sensor, 20: brake ECU, 21: brake sensor, 22: brake actuator, 31: CPU, 32: ROM, 33: RAM, 40: steering ECU, 41 : Motor driver, 42: Steering motor, 60: Grid map, 62: Unit area

Claims (1)

Mounted on the vehicle,
An obstacle, a road surface, and a white line are detected based on parallax information acquired from the captured image in front of the vehicle captured by the two camera sensors and pixel information including a luminance value, and the obstacle, the road surface, and the white line are detected. Peripheral information acquisition means for acquiring the position as peripheral information;
Among the detected obstacles, there is a front obstacle that is an obstacle whose predicted collision time is estimated to be required before the vehicle collides in the forward direction of the vehicle, which is equal to or less than a predetermined first time threshold. An avoidance route setting means for setting an avoidance route for avoiding a collision with the front obstacle,
Reliability calculation means for calculating a reliability that is a measure indicating whether the avoidance route is safe as a travel route of the vehicle;
Automatic braking control for executing automatic braking control for automatically applying a braking force to the vehicle when the predicted collision time to the forward obstacle is not more than a predetermined second time threshold which is not more than the first time threshold. Means,
When the predicted collision time to the forward obstacle reaches a predetermined third time threshold value that is equal to or less than the second time threshold value, the vehicle is in the automatic braking control and is reduced by the automatic braking control. Determining whether or not a specific condition is satisfied that a braking distance based on speed is longer than a distance to the forward obstacle and the reliability of the avoidance path is equal to or greater than a predetermined reliability threshold; If it is determined that the condition is satisfied, automatic steering control is executed to automatically change the turning angle of the steering wheel of the vehicle so that the vehicle travels along the avoidance route, and the specific condition is not satisfied. If it is determined, automatic steering control means that does not execute the automatic steering control,
A collision avoidance control device comprising:
Furthermore, it is unknown whether each of the unit areas when the area in front of the vehicle is divided into a plurality of unit areas is an obstacle area where an obstacle exists, or whether the vehicle can travel safely. A unit region specifying means for specifying whether it is a certain unknown region based on the peripheral information;
With
The unit area has a different cost depending on the type of area, and when the distance from the vehicle to the obstacle area and the distance from the vehicle to the unknown area are substantially the same, The cost is set higher than the cost of the unknown area,
The reliability calculation means includes
A region through which the vehicle passes when the vehicle travels along the avoidance path for each calculation period until the predicted collision time to the front obstacle reaches the third time threshold from the first time threshold. Based on the number and cost of the obstacle area existing in the avoidance area including, and the number and cost of the unknown area, to calculate the avoidance area cost that is a measure indicating the risk of the avoidance area,
The avoidance area cost is set to increase as the number of obstacle areas and the number of unknown areas existing in the avoidance area increase.
When the avoidance area cost is equal to or higher than a predetermined cost threshold, the reliability is calculated as a value obtained by subtracting a predetermined value from the reliability of the immediately preceding calculation cycle, and when the avoidance area cost is less than the cost threshold, The reliability is calculated as a value obtained by adding a predetermined value to the reliability of the previous calculation cycle.
Configured as
Collision avoidance control device.

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