JP7371756B2 - lane change assist device - Google Patents

Description

The present invention relates to a lane change support device capable of executing lane change support control that supports steering operations for changing lanes.

Patent Document 1 discloses a lane change support device that can perform lane change support control that supports steering operation of a steering wheel when a vehicle changes lanes.

This lane change support device moves a vehicle equipped with the lane change support device (hereinafter referred to as the "own vehicle") from the lane in which the own vehicle is currently traveling (hereinafter referred to as the original lane) to a lane adjacent to the original lane and It is possible to calculate a target trajectory function that defines a target trajectory for changing lanes to a target lane, which is a lane in which the driver of the own vehicle desires to move. Note that the direction of the target lane when viewed from the original lane can be set by operating means provided in the host vehicle. In other words, the lane movement direction of the vehicle under lane change support control can be set by the operating means.

This type of target trajectory function is, for example, a function that calculates a target lateral position of the own vehicle corresponding to time and using a lane center line extending parallel to the original lane from the center in the lane width direction of the original lane as a reference. That is, in order to calculate the target trajectory function, the lane change support device needs to recognize the position of the lane center line of the original lane.
For this purpose, the lane change support device recognizes a pair of marking lines (white lines) that respectively define the left and right edges of the original lane, using, for example, photographic data acquired by a camera. Furthermore, the lane change assist device recognizes the center position in the lane width direction between the left and right lane markings as the position where the lane center line of the original lane passes.

Furthermore, the lane change support device controls the steering angle of the steered wheels of the own vehicle so that the own vehicle travels along the target trajectory defined by the calculated target trajectory function.
The lane change support device executes lane change support control in this manner.

Japanese Patent Application Publication No. 2016-126360 Japanese Patent Application Publication No. 2002-163642

The camera mounted on the own vehicle cannot always recognize the pair of lane markings in the original lane. That is, the camera may temporarily recognize only one lane marking and not the other lane marking.
However, by the time the camera no longer recognizes the other lane marking, the lane change support device may have already recognized the lane width of the original lane. Furthermore, the lane change support device may be able to recognize the lane width of the original lane from information on map data of a car navigation system installed in the own vehicle, for example.
Even if the camera recognizes only one lane marking, if the lane change assist device recognizes the lane width of the original lane, the lane change assist device will change the direction of the original lane based on the position and lane width of one marking line of the original lane. It is possible to recognize (calculate) the position of the lane center line.
Therefore, the lane change support device can perform lane change support control even when the camera recognizes only one of the pair of lane marking lines of the original lane.

However, when the lane change support device executes such lane change support control, the following problems may occur.

The road shown in FIG. 6 has three lanes (lane 1, lane 2, and lane 3). A vehicle travels on this road in the direction of arrow A.
Further, in front of the host vehicle located at position X1 on lane 1, lane 1 curves and merges with lane 2. In other words, the number of lanes on the road in front of the own vehicle located at position X1 has decreased from "3" to "2".
Furthermore, at the confluence (curved part) of lane 1 with lane 2, the left lane marking line of lane 1 is drawn as a solid line. On the other hand, no marking line is drawn on this road to define the right edge of the junction of lane 1 and lane 2.

Here, it is assumed that the own vehicle located at position X1 is executing lane change support control.

Note that the direction of the target lane when viewed from the original lane is set to the right by the operation means. That is, the driver of the own vehicle located at position X1 expects that the own vehicle will change lanes from lane 1 to lane 2 by the lane change support control. In other words, the driver expects that his vehicle will change lanes from lane 1 to lane 2 on the right by lane change support control.
However, when the camera of the vehicle that has moved to position Based on the positional information of the lane marking line on the left side of the merging section No. 1, there is a possibility that the lane center line PCL of Lane 1 is erroneously recognized as being present at the merging section. In other words, the lane change support control may erroneously recognize lane 1 as a lane that extends to a position ahead of the merging point.

Therefore, if the lane change support control of the vehicle C located at position X2 incorrectly recognizes the lane change as described above, there is a risk that the vehicle C located at position be. In other words, even though the driver of the own vehicle expected the own vehicle to change lanes from lane 1 to lane 2 using lane change support control, the driver of the own vehicle suddenly changed lanes from lane 1 to lane 3. There is a risk of it getting lost. In this case, the driver of the vehicle may feel uncomfortable.

The present invention has been made to address the above problems. That is, one of the objects of the present invention is to be able to perform lane change support control when the lane recognition means recognizes only one of a pair of lane markings defining the lane in which the vehicle is traveling; An object of the present invention is to provide a lane change support device that can prevent a vehicle from changing all at once from the lane in which it is traveling to a lane adjacent to a lane adjacent to the lane in which it is traveling when passing through a portion of the road where the number of lanes is reduced. .

In order to achieve the above object, the lane change assist device of the present invention has the following features:
A pair of lane markings (WL) that respectively define the left and right edges of the original lane in which the own vehicle (C) is traveling can be recognized, and when at least one of the lane markings is recognized, the lane recognition means (12) capable of recognizing the relative position of the own vehicle in the lane width direction with respect to the original lane;
The host vehicle traveling in the original lane is moved adjacent to the original lane from one of the left and right sides so that the relative position recognized by the lane recognition means changes along a predetermined target trajectory. Lane change support control means (10, 20) capable of executing lane change support control to change lanes to a target lane;
Equipped with
The lane change assist control means,
When the lane recognition means does not recognize the marking line on the one side of the original lane and recognizes the marking line on the other side, the own vehicle traveling in the original lane crosses the original lane from the one side. The present invention is configured such that execution of the lane change support control so as to change lanes to the target lane adjacent to the lane is prohibited.

The partition line is, for example, a white line.
However, the partition line may include a line different from the white line.

The lane recognition means of the present invention is capable of recognizing a pair of marking lines that respectively define the left and right side edges of the original lane, which is the lane in which the own vehicle is traveling. Further, the lane recognition means is capable of recognizing the relative position of the own vehicle in the lane width direction with respect to the original lane when at least one lane marking is recognized.
Furthermore, the lane change support control means directs the own vehicle traveling in the original lane toward the original lane from one of the left and right sides so that the relative position recognized by the lane recognition means changes along a predetermined target trajectory. It is possible to execute lane change support control that causes the vehicle to change lanes to the adjacent target lane.
That is, when the lane recognition means recognizes only one marking line of the lane in which the vehicle is traveling, the lane change support control means can execute the lane change support control.

However, when the lane recognition means does not recognize the marking line on the one side of the original lane and recognizes the marking line on the other side, the lane change support control means causes the own vehicle traveling in the original lane to change to the one side. It is prohibited to execute lane change support control to change the lane from the original lane to the adjacent target lane.
For example, if the lane recognition means recognizes only the left marking line of the original lane, the lane change support control means moves the own vehicle traveling in the original lane to the target lane to the right of the original lane. Changes are prohibited.

Therefore, for example, the own vehicle located at position X2 in lane 1 in FIG. 6 is prohibited from changing lane from lane 1 (merging area of the original lane) to lane 3 by lane change support control. That is, there is no risk that the own vehicle will be forced to change lanes from lane 1 to lane 3 all at once due to lane change support control.

In the above description, in order to facilitate understanding of the present invention, the names and/or symbols used in the embodiments are added in parentheses to the structures of the invention corresponding to the embodiments described later. However, each component of the present invention is not limited to the embodiment defined by the above reference numerals. Other objects, other features and attendant advantages of the present invention will be readily understood from the following description of embodiments of the invention with reference to the drawings.

1 is a schematic configuration diagram of a lane change assist device according to an embodiment of the present invention. FIG. 3 is a diagram for explaining the operation of a turn signal lever. It is a flow chart showing a steering assistance control routine concerning an embodiment. FIG. 3 is a diagram showing a target trajectory of the own vehicle. FIG. 3 is a diagram illustrating how the host vehicle travels through a portion of the road where the number of lanes decreases while executing lane maintenance support control and lane change support control. FIG. 6 is a diagram illustrating how a vehicle in a comparative example travels through a portion of a road where the number of lanes decreases while executing lane change support control.

Hereinafter, a steering support device according to an embodiment of the present invention will be described with reference to the drawings.

A steering support device according to an embodiment of the present invention is applied to a vehicle C (hereinafter, it may be referred to as "host vehicle C" to distinguish it from other vehicles). As shown in FIG. 1, the host vehicle C includes a driving support ECU 10, an electric power steering ECU 20, a meter ECU 30, a steering ECU 40, an engine ECU 50, a brake ECU 60, and a navigation ECU 70.

These ECUs are electrical control units that include a microcomputer as a main part, and are connected to each other via a CAN (Controller Area Network) 100 so that they can transmit and receive information. In this specification, a microcomputer includes a CPU, a ROM, a RAM, a nonvolatile memory, an interface I/F, and the like. The CPU realizes various functions by executing instructions (programs, routines) stored in the ROM. Some or all of these ECUs may be integrated into one ECU.

Further, connected to the CAN 100 are a plurality of types of vehicle condition sensors 80 that detect vehicle conditions, and a plurality of types of driving operation condition sensors 90 that detect driving operation conditions. The vehicle condition sensor 80 includes, for example, a vehicle speed sensor that detects the running speed of the vehicle, a longitudinal G sensor that detects the longitudinal acceleration of the vehicle, a lateral G sensor that detects the lateral acceleration of the vehicle, and a yaw rate of the vehicle. This includes a yaw rate sensor, etc.

The driving operation state sensor 90 includes an accelerator operation amount sensor that detects the amount of operation of the accelerator pedal, a brake operation amount sensor that detects the amount of operation of the brake pedal, a brake switch that detects whether or not the brake pedal is operated, and a steering angle. These include a steering angle sensor, a steering torque sensor that detects steering torque, and a shift position sensor that detects a shift position of a transmission.

Information detected by vehicle condition sensor 80 and driving operation condition sensor 90 (referred to as sensor information) is transmitted to CAN 100. In each ECU, the sensor information transmitted to CAN 100 can be used as appropriate.

The driving support ECU 10 is a central control device that provides driving support to the driver, and performs lane change support control, lane maintenance support control, and following distance control. As shown in FIG. 1, a peripheral sensor 11 is connected to the driving support ECU 10.

The peripheral sensor 11 includes a radar transmitting/receiving section and a signal processing section (not shown), and the radar transmitting/receiving section emits radio waves in the millimeter wave band (hereinafter referred to as "millimeter waves"). Receives millimeter waves (i.e., reflected waves) reflected by three-dimensional objects (for example, other vehicles, pedestrians, bicycles, buildings, etc.) that exist within the device. The signal processing unit uses the phase difference between the transmitted millimeter wave and the received reflected wave, the attenuation level of the reflected wave, the time from transmitting the millimeter wave to receiving the reflected wave, etc. Information representing the distance to the object, the relative speed between the vehicle C and the three-dimensional object, the relative position (direction) of the three-dimensional object to the vehicle C, etc. (hereinafter referred to as surrounding information) is acquired every predetermined period of time. It is supplied to the driving support ECU 10. Using this surrounding information, it is possible to detect the longitudinal component and the lateral component of the distance between the own vehicle C and the three-dimensional object, and the longitudinal component and the lateral component of the relative speed between the own vehicle C and the three-dimensional object. .

Although the surrounding sensor 11 is a radar sensor in this embodiment, other sensors such as a clearance sonar or a lidar sensor may be used instead.

Further, a camera sensor 12 is connected to the driving support ECU 10. The camera sensor 12 includes a camera section and a lane recognition section that analyzes image data taken and obtained by the camera section and recognizes a white line WL, which is a type of road marking line. The camera sensor 12 (camera unit) photographs the scenery in front of the host vehicle C. The camera sensor 12 (lane recognition unit) repeatedly supplies information regarding the recognized white line WL to the driving support ECU 10 at a predetermined calculation cycle.

The camera sensor 12 recognizes a lane representing an area defined by a pair of white lines WL (see FIG. 5), and also detects the relative position of the own vehicle C with respect to the lane based on the positional relationship between the white line WL and the own vehicle C. It is now possible to detect positional relationships. Here, the position of the own vehicle C is the position of the center of gravity of the own vehicle C. Furthermore, the lateral position of the own vehicle C represents the position of the center of gravity of the own vehicle C in the lane width direction, and the lateral speed of the own vehicle C represents the speed of the center of gravity of the own vehicle C in the lane width direction. The lateral acceleration of the vehicle C represents the acceleration of the center of gravity of the own vehicle C in the lane width direction. These are determined based on the relative positional relationship between the white line WL detected by the camera sensor 12 and the own vehicle C.

As shown in FIG. 5, the camera sensor 12 sets a lane center line CL (dotted chain line) that is the center position in the width direction of the left and right white lines WL in the lane in which the own vehicle C is traveling. This lane center line CL is used as a target travel line in lane keeping support control, which will be described later. The camera sensor 12 also calculates the curvature Cu of the curve of the lane center line CL.

When the camera sensor 12 recognizes (simultaneously) a pair of white lines WL that respectively define the left and right edges of the lane in which the host vehicle C is traveling, the camera sensor 12 detects a direction in the lane width direction between the recognized pair of white lines WL. The center position is recognized as the position through which the lane center line CL of this lane passes.

Further, the camera sensor 12 cannot always recognize the pair of white lines WL of the lane in which the own vehicle C is traveling. That is, the camera sensor 12 may temporarily recognize only one white line WL and not recognize the other white line WL.
However, as will be described later, the map information stored in the map database 72 connected to the navigation ECU 70 includes information regarding the lane width of the road (each lane). Therefore, even in such a situation, the camera sensor 12 can recognize the lane width of this lane based on the information in the map database 72. Furthermore, if the camera sensor 12 has already simultaneously recognized the pair of white lines WL of this lane at least once before such a situation occurs, the camera sensor 12 recognizes the pair of white lines WL of this lane based on the acquired position information of the pair of white lines WL. can recognize the lane width of this lane.
The camera sensor 12 can recognize (calculate) the position of the lane center line CL of this lane based on the information regarding the lane width of this lane and the information regarding the position of one of the white lines WL.
Note that the road shown in FIG. 5 has a plurality of lanes 1, 2, and 3. In this case, when the camera sensor 12 of the own vehicle C recognizes the lane width of lane 1 by recognizing the left and right white lines WL of lane 1, the camera sensor 12 also recognizes the lane width of lane 2 and lane 3. It is recognized as the same as the lane width. However, if the information stored in the map database 72 indicates that the lane width of lane 1 is different from the lane widths of lanes 2 and 3, the camera sensor 12 determines that the lane width of lanes 2 and 3 is determined by the map database 72. The lane width is recognized as indicated by the information stored in the lane.

In addition, the camera sensor 12 detects not only the lane in which the own vehicle C is traveling but also the lanes adjacent to this lane, the type of white line WL detected (solid line, broken line), the distance between the adjacent left and right white lines WL. Information regarding the white line WL, such as (lane width) and the shape of the white line WL, is also supplied to the driving support ECU 10 at a predetermined calculation cycle. When the white line WL is a solid line, a vehicle is prohibited from changing lanes by straddling the white line WL. On the other hand, if the white line WL is a broken line (a white line formed intermittently at regular intervals), a vehicle is permitted to change lanes by straddling the white line WL.

The driving support ECU 10 receives surrounding information supplied from the surrounding sensor 11, information regarding lanes obtained based on white line recognition by the camera sensor 12, vehicle state detected by the vehicle state sensor 80, and driving operation state sensor 90. Lane change support control, lane keeping support control, and inter-vehicle distance control are implemented based on the driving operation state detected by the system.

A setting controller 14 operated by the driver is connected to the driving support ECU 10. The setting operation device 14 is an operation device for performing settings such as whether to perform each of lane change support control, lane maintenance support control, and following vehicle distance control. The driving support ECU 10 receives a setting signal from the setting operation device 14 and determines whether each control is to be performed or not. In this case, if execution of following inter-vehicle distance control is not selected, lane change support control and lane keeping support control are also automatically set not to be performed. Further, if implementation of lane keeping support control is not selected, lane change support control is also automatically set not to be performed.

Furthermore, the setting operation device 14 also has a function of inputting parameters representing the driver's preferences when implementing the above control.

The electric power steering ECU 20 is a control device for an electric power steering device. Hereinafter, the electric power steering ECU 20 will be referred to as an EPS/ECU (Electric Power Steering ECU) 20. The EPS/ECU 20 is connected to a motor driver 21. The motor driver 21 is connected to a steering motor 22. The steering motor 22 is incorporated into a "steering mechanism including a steering wheel, a steering shaft connected to the steering wheel, a steering gear mechanism, etc." of a vehicle (not shown). The EPS/ECU 20 detects the steering torque that the driver inputs to the steering wheel (not shown) using a steering torque sensor provided on the steering shaft, and controls the energization of the motor driver 21 based on this steering torque. The steering motor 22 is driven. Steering torque is applied to the steering mechanism by driving the assist motor, thereby assisting the driver's steering operation.

Further, when the EPS/ECU 20 receives a steering command from the driving support ECU 10 via the CAN 100, the EPS/ECU 20 drives the steering motor 22 with a control amount specified by the steering command to generate steering torque. This steering torque is different from the above-mentioned steering assist torque that is applied to lighten the driver's steering operation (steering wheel operation), and the steering torque is applied to the steering mechanism by a steering command from the driving support ECU 10 without requiring the driver's steering operation. represents the torque applied to

Note that even if the EPS/ECU 20 is receiving a steering command from the driving support ECU 10, if the steering torque due to the driver's steering wheel operation is detected, the EPS/ECU 20 will control the steering torque when the steering torque is larger than the threshold value. The system gives priority to the driver's steering and generates steering assist torque to lighten the steering effort.

The meter ECU 30 is connected to a display 31 and left and right turn signals 32 (meaning turn signal lamps, sometimes referred to as turn lamps). The display 31 is, for example, a multi-information display provided in front of the driver's seat, and displays various information in addition to displaying measured values of meters such as vehicle speed. For example, upon receiving a display command according to the driving support state from the driving support ECU 10, the meter ECU 30 causes the display 31 to display a screen specified by the display command. Note that as the display device 31, a head-up display (not shown) may be used instead of or in addition to the multi-information display. When employing a head-up display, it is preferable to provide a dedicated ECU that controls the display of the head-up display.

In addition, the meter ECU 30 includes a turn signal drive circuit (not shown), and when receiving a turn signal blinking command via the CAN 100, the meter ECU 30 blinks the turn signal 32 in the direction (right, left) specified by the turn signal blinking command. let Moreover, while the meter ECU 30 is blinking the blinker 32, it transmits blinker blinking information indicating that the blinker 32 is in a blinking state to the CAN 100. Therefore, other ECUs can grasp the blinking state of the turn signal 32.

The steering ECU 40 is connected to a turn signal lever 41. The turn signal lever 41 is an operating device for operating (blinking) the turn signal 32, and is provided on the steering column. The turn signal lever 41 is provided so as to be able to swing around the spindle O in two stages of operation strokes in each of the clockwise operation direction and the counterclockwise operation direction.

The turn signal lever 41 of this embodiment also serves as an operating device with which the driver requests lane change support control. As shown in FIG. 2, the turn signal lever 41 has a first stroke, which is a position rotated by a first angle θW1 from the neutral position PN in each of the counterclockwise operating direction and clockwise operating direction about the support shaft O. It is configured to be selectively operable between position P1L (P1R) and second stroke position P2L (P2R), which is a position rotated by a second angle θW2 (>θW1) from neutral position PN. At the first stroke position P1L (P1R), the turn signal lever 41 returns to the neutral position PN when the driver's lever operating force is released, and at the second stroke position P2L (P2R), even when the lever operating force is released, This state is maintained by a locking mechanism. In addition, when the steering wheel is rotated in the opposite direction and returned to the neutral position while the turn signal lever 41 is held at the second stroke position P2L (P2R), or when the driver moves the turn signal lever 41 toward the neutral position. When the return operation is performed, the lock by the lock mechanism is released and returned to the neutral position PN.

The turn signal lever 41 has a first switch 411L (411R) that is turned on only when it is tilted to the first stroke position P1L (P1R), and a first switch 411L (411R) that is turned on only when it is tilted to the second stroke position P2L (P2R). A second switch 412L (412R) is provided.

The steering ECU 40 detects the operation state of the turn signal lever 41 based on the states of the first switch 411L (411R) and the second switch 412L (412R), and moves the turn signal lever 41 to the first stroke position P1L (P1R). A turn signal blinking command including information representing the operating direction (left and right) is transmitted to the meter ECU 30 in each of the state where the switch is tilted down and the state where it is tilted down to the second stroke position P2L (P2R). .

In addition, the steering ECU 40 detects that the turn signal lever 41 is continuously held at the first stroke position P1L (P1R) for a preset time (lane change request confirmation time: for example, 1 second) or more. In this case, a lane change support request signal including information representing the direction of operation (left or right) is output to the driving support ECU 10. Therefore, if the driver wants to receive lane change assistance while driving, he or she only has to move the turn signal lever 41 to the first stroke position P1L (P1R) in the lane change direction and hold it for a set time or longer. This operation is called a lane change assistance request operation.

In this embodiment, the turn signal lever 41 is also used as an operating device for the driver to request lane change assistance, but instead, a dedicated lane change assistance request operating device may be provided on the steering wheel or the like. .

Engine ECU 50 is connected to engine actuator 51. The engine actuator 51 is an actuator for changing the operating state of the internal combustion engine 52. In this embodiment, the internal combustion engine 52 is a gasoline fuel injection, spark ignition, multi-cylinder engine, and includes a throttle valve for adjusting the amount of intake air. Engine actuator 51 includes at least a throttle valve actuator that changes the opening degree of the throttle valve. Engine ECU 50 can change the torque generated by internal combustion engine 52 by driving engine actuator 51 . Torque generated by the internal combustion engine 52 is transmitted to drive wheels (not shown) via a transmission (not shown). Therefore, by controlling the engine actuator 51, the engine ECU 50 can control the driving force of the own vehicle C and change the acceleration state (acceleration).

Brake ECU 60 is connected to brake actuator 61. The brake actuator 61 is provided in a hydraulic circuit between a master cylinder (not shown) that pressurizes hydraulic oil by the force applied to the brake pedal, and friction brake mechanisms 62 provided on the left and right front and rear wheels. The friction brake mechanism 62 includes a brake disc 62a fixed to the wheel and a brake caliper 62b fixed to the vehicle body. The brake actuator 61 adjusts the hydraulic pressure supplied to the wheel cylinder built into the brake caliper 62b according to instructions from the brake ECU 60, and operates the wheel cylinder using the hydraulic pressure to press the brake pad against the brake disc 62a to create friction. Generates braking force. Therefore, the brake ECU 60 can control the braking force of the host vehicle C by controlling the brake actuator 61.

Connected to the navigation ECU 70 are a GPS receiver 71 that receives GPS signals for detecting the current position of the vehicle C, a map database 72 that stores map information, etc., and a touch panel (touch panel display) 73. . The navigation ECU 70 specifies the current position of the own vehicle C based on the GPS signal, performs various calculation processes based on the position of the own vehicle C and map information stored in the map database 72, and displays the touch panel 73. Route guidance is provided using .

The map information stored in the map database 72 includes road information. The road information includes parameters indicating the position and shape of the road (for example, the radius of curvature or curvature of the road, the lane width of the road, the number of lanes, the position of the center line of each lane, etc.). The road information also includes road type information that can distinguish whether the road is a road exclusively for motor vehicles or not.

<Control processing performed by driving support ECU 10>
Next, the control processing performed by the driving support ECU 10 will be explained. The driving support ECU 10 performs lane change support control when a lane change support request is received in a situation where both lane keeping support control and following inter-vehicle distance control are being performed. Therefore, first, lane keeping support control and following vehicle distance control will be briefly explained.

<Lane Keeping Assist Control (LTA)>
Lane keeping support control applies steering torque to the steering mechanism to control the driver's steering operation so that the position of the vehicle C is maintained near the target travel line within the "lane in which the vehicle C is traveling." This is a control that supports In this embodiment, the target travel line is the lane center line CL, but a line offset in the lane width direction by a predetermined distance from the lane center line CL may also be adopted.
Hereinafter, lane keeping support control will be referred to as LTA (Lane Tracing Assist). LTA is well known, and its control contents are disclosed in, for example, Japanese Patent Application Publication No. 2008-195402, Japanese Patent Application Publication No. 2009-190464, Japanese Patent Application Publication No. 2010-6279, and Japanese Patent No. 4349210. There is.
The driving support ECU 10 executes LTA when LTA is requested by operating the setting controller 14 and predetermined LTA start conditions are satisfied. In order for the driving support ECU 10 to execute LTA, the camera sensor 12 needs to recognize the lane center line CL of the lane. Therefore, the LTA start condition includes at least ``the camera sensor 12 (lane recognition unit) recognizes only one of the pair of white lines WL that define the left and right side edges of the lane and the lane width, or This includes the requirement that the camera sensor 12 recognizes both white lines WL at the same time.

<Following distance control (ACC)>
Following distance control maintains the following distance between the preceding vehicle and the own vehicle C at a predetermined distance when it is determined based on surrounding information that there is a preceding vehicle traveling in front of the own vehicle C. This control causes the own vehicle C to follow the preceding vehicle, and when there is no preceding vehicle, causes the own vehicle C to travel at a constant speed at a set vehicle speed. This control is executed by driving support ECU 10 controlling engine actuator 51 and/or brake actuator 61 via engine ECU 50 and/or brake ECU 60. Hereinafter, the follow-up distance control will be referred to as ACC (adaptive cruise control). ACC is well known, and its control contents are disclosed in, for example, Japanese Patent Application Publication No. 2014-148293, Japanese Patent Application Publication No. 2006-315491, Japanese Patent No. 4172434, and Japanese Patent No. 4929777.
The driving support ECU 10 executes ACC when ACC is requested by operating the setting controller 14 .

<Lane change assist control (LCA)>
The lane change support control monitors the surroundings of the own vehicle C by using the surrounding information acquired by the surrounding sensor 11, and after it is determined that it is possible to change lanes safely, the lane change support control monitors the surroundings of the own vehicle C. At the same time, this is a control that supports the driver's steering operation (lane change operation) by applying steering torque to the steering mechanism so that the vehicle C moves from the lane in which it is currently traveling to an adjacent lane. Therefore, according to the lane change support control, the lane in which the host vehicle C is traveling can be changed without requiring any steering operation (steering wheel operation) by the driver. Hereinafter, lane change assist control will be referred to as LCA (lane change assist).

Like LTA, LCA is a control of the lateral position of vehicle C with respect to the lane, and is performed in place of LTA when a lane change assistance request is received while LTA and ACC are being performed. Hereinafter, LTA and LCA will be collectively referred to as steering support control, and the state of the steering support control will be referred to as the steering support control state.

Note that the steering assist device supports the driver's steering operation, so when implementing steering assist control (LTA, LCA), it generates a steering force for control so that the driver's steering operation is given priority. let Therefore, even during steering assistance control, the driver can move the vehicle C in the intended direction by operating the steering wheel himself.

FIG. 3 shows a steering support control routine executed by the driving support ECU 10. The steering support control routine is executed when the LTA execution permission condition is satisfied. The LTA implementation permission conditions include that LTA implementation is selected by the setting controller 14, that ACC is implemented, and that LTA start conditions are met.

When the driving support ECU 10 starts the steering support control routine, in step S11, the driving support ECU 10 sets the steering support control state to the LTA ON state. The LTA ON state represents a control state in which LTA is implemented.

Subsequently, in step S12, the driving support ECU 10 determines whether the LCA start condition is satisfied.

The LCA start condition is satisfied, for example, when all of the following conditions are satisfied.
1. A lane change assistance request operation is detected.
2. Implementation of LCA has been selected by the setting operation device 14.
3. The white line WL in the turn signal operation direction (the white line WL that is the boundary between the original lane, which is the lane in which the host vehicle C is currently traveling, and the target lane) is a broken line.
4. The LCA implementation feasibility determination result of surrounding monitoring is acceptable (according to the surrounding information obtained by the surrounding sensor 11, no obstacles (other vehicles, etc.) that would impede the lane change are detected, and the lane can be changed safely. ).
5. The road is a road exclusively for automobiles (the road type information acquired from the navigation ECU 70 indicates a road exclusively for automobiles).
6. The vehicle speed of own vehicle C is within the LCA permitted vehicle speed range.
7. The camera sensor 12 (lane recognition unit) recognizes only one of the left and right white lines WL of a pair of white lines WL defining the left and right edges of the original lane, and the driving support ECU 10 receives information regarding the lane width of the original lane. If the lane change direction has been acquired, the lane change direction of the own vehicle C by the lane change support request operation and the direction of the one white line WL as seen from the own vehicle C are the same, or both of the pair of white lines WL are The camera sensor 12 must recognize the information at the same time. Note that, for example, if the map information in the map database 72 includes information regarding the lane width of the road (each lane), or if the information regarding the lane width of the road is stored in the memory (ROM) of the driving support ECU 10 as a fixed value (e.g. 3.5 m), the driving support ECU 10 can acquire information regarding the lane width of the original lane even if the camera sensor 12 recognizes only one white line WL.
For example, condition "4." is satisfied when it is estimated that an appropriate inter-vehicle distance between the vehicle C and another vehicle traveling in the target lane will be maintained after changing lanes, based on the relative speed of the vehicle C and another vehicle traveling in the target lane. .
Note that the LCA start conditions are not limited to these conditions and can be arbitrarily set as long as they include condition "7.".

If the LCA start condition is not met, the driving support ECU 10 returns the process to step S11 and continues the LTA.

If the LCA start condition is satisfied while LTA is being executed (step S12: Yes), the driving support ECU 10 executes LCA instead of LTA in step S13. The driving support ECU 10 then transmits an LCA execution display command to the meter ECU 30.
For example, when conditions "1." to "6." are satisfied, and the camera sensor 12 (lane recognition unit) of own vehicle C traveling in lane 3 in FIG. 5 recognizes the white line WL on the right side of lane 3, If the lane change direction of the own vehicle C by the lane change support request operation is to the left when only the white line WL on the left side is recognized and the lane width of lane 3 is recognized, the driving support ECU 10 selects Yes in step S12. It is determined that

The driving support ECU 10 calculates a target trajectory function representing the target trajectory of the host vehicle C using a well-known method in step S13. This target trajectory function is a function that calculates the target lateral position (lane width direction position) of the own vehicle C with respect to the lane center line CL of the original lane based on time.

Once the target trajectory function is calculated, the driving support ECU 10 performs steering control based on the target trajectory function in subsequent step S14.
That is, the driving support ECU 10 calculates the target steering angle of the steered wheels at the current time using the value obtained by substituting the current time into the target trajectory function. At this time, the driving support ECU 10, for example, reduces the error between the lateral position of the host vehicle C obtained by substituting the current time into the target trajectory function and the actual lateral position at the current time obtained by the camera sensor 12. The target rudder angle is calculated. That is, the arithmetic expression used by the driving support ECU 10 to determine the target steering angle includes a feedback term. Note that this feedback term may reduce errors in the lateral velocity and lateral acceleration of the host vehicle in addition to the lateral position error.
The driving support ECU 10 then transmits information regarding this target steering angle to the EPS/ECU 20. Then, the EPS/ECU 20 drives and controls the steering motor 22 so that the steered wheels rotate at the target steering angle at the current time. As a result, the host vehicle C executes a lane change along the target trajectory.

Further, after completing the process in step S14, the driving support ECU 10 determines in step S15 whether or not a predetermined LCA interruption condition is satisfied. The LCA interruption condition of this embodiment is satisfied when the above-mentioned "7." of the LCA start condition is no longer satisfied. That is, the camera sensor 12 (lane recognition unit) recognizes only one of the left and right white lines WL of a pair of white lines WL that respectively define the left and right edges of the original lane, and the driving support ECU 10 recognizes only one of the white lines WL on the left and right sides of the pair of white lines WL that respectively define the left and right edges of the original lane, and the driving support ECU 10 recognizes the lane width of the original lane. When the lane change direction of the own vehicle C due to the lane change assistance request operation is different from the direction of the white line WL as seen from the vehicle C when information has been acquired, or when the camera detects both of the pair of white lines WL. When the sensors 12 no longer recognize each other at the same time, the LCA interruption condition is met.

If the driving support ECU 10 determines Yes in step S15, it interrupts LCA, returns to step S11, and sets the steering support control state to the LTA ON state. That is, the driving support ECU 10 restarts LTA.

The driving support ECU 10 that has determined No in step S15 determines whether or not the LCA completion condition is satisfied in step S16. The LCA completion condition of this embodiment is when the lateral position of the host vehicle C matches the final target lateral position represented by the target trajectory (target trajectory function) calculated in step S13 (the lateral speed of the host vehicle C becomes zero). holds true when). If the LCA completion condition is not satisfied, the driving support ECU 10 returns the process to step S14 and repeatedly executes the processes of step S14 and step S15 at a predetermined calculation cycle. Note that the final target lateral position represented by the target trajectory is a position on the lane center line CL of the target lane.

On the other hand, if it is determined in step S16 that the LCA completion condition is satisfied, the driving support ECU 10 sets the steering support control state to the LTA ON state in step S17. That is, LCA is ended and LTA is restarted. As a result, steering control is performed so that the host vehicle C travels along the lane center line CL in the target lane. When the driving support ECU 10 sets the steering support control state to the LTA ON state in step S17, the process returns to step S11, and the above-described steering support control routine continues as it is.

The driving support ECU 10 transmits a blinking command for the turn signal 32 in the direction of the turn signal operation to the meter ECU 30 during a period from the start of LCA to the end of this steering support control routine. The blinker 32 blinks before the LCA is started by a blinking command transmitted from the steering ECU 40 in response to the operation of the blinker lever 41 to the first stroke position P1L (P1R). Even if the blinking command transmitted from the steering ECU 40 is stopped, the meter ECU 30 continues blinking the turn signal 32 while the blinking command is transmitted from the driving support ECU 10.

According to the lane change support device of this embodiment described above, in step S12 and step S15 of the flowchart of FIG. When only one white line WL is recognized and the lane width of the original lane is recognized, the lane change direction of the own vehicle C by the lane change support request operation and the direction of the one white line WL as seen from the vehicle C. are different from each other, LCA control is not executed (interrupted). Therefore, the effects described below can be achieved.

The road shown in FIG. 5 has three lanes (lane 1, lane 2, and lane 3). A vehicle travels on this road in the direction of arrow A.
Further, in front of the host vehicle C located at position X1 on lane 1, lane 1 curves and merges with lane 2. In other words, the number of lanes on the road in front of the own vehicle C located at position X1 has decreased from "3" to "2".
Furthermore, at the confluence (curved part) of lane 1 with lane 2, the white line WL on the left side of lane 1 is drawn as a solid line. On the other hand, the white line WL that defines the right edge of the junction of lane 1 and lane 2 is not drawn on this road. That is, the camera sensor 12 of the own vehicle C can only recognize the left white line WL at the merging section.

Here, the own vehicle C located at position Assume a case.
The driver of own vehicle C located at position X1 anticipates that own vehicle C will change lanes from lane 1, which is the original lane, to lane 2, which is the target lane, based on LCA. In other words, the driver expects that his vehicle C will change lanes from lane 1 to lane 2 on the right side based on LCA.
However, when the camera sensor 12 of the own vehicle C, which has moved to position X2 above the merging area of lane 1 due to LTA, recognizes the white line WL on the left side of the merging area, the camera sensor 12 displays the lane width information of lane 1 and Based on the positional information of the white line WL on the left side of the merging area, there is a possibility that the vehicle may erroneously recognize that the lane center line PCL of lane 1 is present at the merging area. In other words, there is a risk that the camera sensor 12 may erroneously recognize lane 1 as a lane that extends to a position ahead of the merging point.

Therefore, if the camera sensor 12 of the own vehicle C located at position X2 incorrectly recognizes lane 1 in this way and the own vehicle C starts LCA at position There is a risk of changing lanes to lane 3 along the target trajectory indicated by PM. In other words, even though the driver of vehicle C expected to change lanes from lane 1 (source lane) to lane 2 (target lane) using LCA, vehicle C suddenly changed from lane 1 to lane 3. There is a risk that it may change. In this case, the driver of the own vehicle C may feel uncomfortable.

However, in this embodiment, in this case, the camera sensor 12 recognizes only the white line WL on the left side of the merging section of lane 1. On the other hand, the lane change direction of the host vehicle C from lane 1 defined by the rotational direction of the turn signal lever 41 is "to the right." That is, the camera sensor 12 recognizes only one of the left and right white lines WL of the pair of white lines WL of lane 1, which is the original lane (the left white line WL), and the camera sensor 12 recognizes only one of the pair of white lines WL of lane 1, which is the original lane (and lanes 2 and 3). When the lane width of the vehicle C is recognized, the lane change direction (right side) of the own vehicle C due to the lane change assistance request operation and the direction (left side) of the one white line WL as seen from the vehicle C are different from each other. Therefore, the driving support ECU 10 determines No in step S12 and/or Yes in step S15.
Therefore, in this embodiment, the host vehicle C located at position X2 does not perform LCA. Therefore, there is no possibility that the host vehicle C suddenly changes lanes from lane 1 (position X2) to lane 3 along the target trajectory indicated by arrow PM.

On the other hand, assume, for example, that the own vehicle C moves to position X3 on lane 2 by LTA. When the camera sensor 12 of the own vehicle C located at the position When the direction is to the right, the own vehicle C changes lanes from lane 2 (position X3) to position X4 on lane 3 along the target trajectory indicated by arrow M according to LCA.

Although the lane change assist device according to the present embodiment has been described above, the present invention is not limited to the above embodiment, and various changes can be made without departing from the purpose of the present invention.

For example, in the present embodiment, the premise for implementing LCA is that the steering support control state is the LTA/ON state (a state in which LTA is being implemented), but such a premise is not necessarily true. do not need. Also. There is no need to assume that ACC is being implemented. Furthermore, in the present embodiment, LCA is performed on the condition that the road on which the host vehicle C travels is a road exclusively for automobiles, but such a condition does not necessarily need to be provided.

10... Driving support ECU, 11... Peripheral sensor, 12... Camera sensor, 20... EPS/ECU, 21... Motor driver, 22... Steering motor, 40... Steering ECU, 41... Turn signal lever, 80... Vehicle condition sensor, 90...Driving operation state sensor, CL...Lane center line, WL...White line (marker line).

Claims (1)

When both of a pair of marking lines defining the left and right edges of the original lane in which the own vehicle is traveling are recognized, the lane width of the own vehicle with respect to the original lane is determined based on the pair of marking lines. Recognize the relative position of the direction,
When only one of the pair of marking lines of the original lane is recognized and the lane width of the original lane is recognized, based on the recognized one marking line and the lane width. recognizing the relative position of the own vehicle in the lane width direction with respect to the original lane;
lane recognition means;
The host vehicle traveling in the original lane is moved adjacent to the original lane from one of the left and right sides so that the relative position recognized by the lane recognition means changes along a predetermined target trajectory. Lane change support control means capable of executing lane change support control to change lanes to a target lane;
Equipped with
The lane change support control means includes:
If the lane recognition means recognizes both of the pair of marking lines of the original lane, and if the lane recognition means recognizes only one of the pair of marking lines of the original lane and the lane width, and the direction of the lane change of the host vehicle and the direction of the recognized one of the lane markings as seen from the host vehicle are the same. Allows the start of lane change assist control,
In the case where the lane change support control is started when the lane recognition means recognizes both of the pair of marking lines of the original lane, and during the execution of the lane change support control, the lane recognition means recognizes both of the pair of marking lines of the original lane. interrupting the lane change support control when both of the pair of marking lines of the original lane are no longer recognized at the same time;
The lane recognition means recognizes only one of the pair of marking lines of the original lane and the lane width of the original lane, and also recognizes the lane change direction of the own vehicle and the lane width as seen from the own vehicle. When the lane change support control is started in a situation where the directions of the one pair of lane markings in the original lane are the same, the lane recognition means no longer recognizes both of the pair of lane markings in the original lane at the same time. When the lane change assist control is interrupted,
Lane change assist device.

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