JP6763343B2 - Lane change support device - Google Patents

Description

The present invention relates to a lane change support device that supports a steering operation for changing lanes.

Conventionally, a lane change support device that supports a steering operation (steering wheel operation) for changing lanes has been known. In such a lane change support device, a target trajectory for changing the course of the own vehicle toward the adjacent lane to which the lane is changed is calculated, and the steering wheels are steered so that the own vehicle travels along the calculated target trajectory. Control the corner. For example, in the device proposed in Patent Document 1, the target passing position of the own vehicle is sequentially calculated based on the position information of a plurality of points along the center line of the adjacent lane and the current position information of the own vehicle. , The target trajectory is calculated based on the target passing position information.

Japanese Unexamined Patent Publication No. 2008-149855

The device proposed in Patent Document 1 recognizes a lane based on road map information, but instead, a device that recognizes a lane based on an image of a camera that captures the front of the own vehicle is also known. There is. In such a device, for example, a lane marking line (hereinafter referred to as a white line) is detected by a camera sensor, and based on the detected white line, the lane in which the own vehicle is traveling before the start of lane change (referred to as the original lane). ) And the lane to which the lane is changed (target lane) adjacent to the original lane are recognized. Then, based on the recognized original lane and the target lane, the target track for moving the own vehicle to the target lane is calculated.

When recognizing a lane using a camera sensor, the recognition accuracy of the target lane may be lower than the recognition accuracy of the original lane. It is also conceivable to calculate the target track after estimating the lane width of the target lane based on the lane width of the original lane, but the lane width of the target lane may be different from the lane width of the original lane. Therefore, if the target track calculated before the start of the lane change is used as it is to complete the lane change, it may not be possible to move the own vehicle to an appropriate position in the target lane.

The present invention has been made to solve the above problems, and an object of the present invention is to appropriately change the lane of the own vehicle to the target lane.

In order to achieve the above object, the feature of the lane change support device of the present invention is
A lane recognition means (12) that recognizes a lane based on an image of a camera that captures the front of the own vehicle and detects the relative positional relationship of the own vehicle with respect to the lane.
A target track calculation means (10) for calculating a target track for changing the lane of the own vehicle toward the target lane based on the relative positional relationship of the own vehicle with respect to the lane.
In the lane change support device provided with the support control means (10, 20) that controls the steering of the steering wheels so that the own vehicle travels along the target track and supports the lane change.
Boundary crossing judgment to determine whether or not the own vehicle straddles the boundary between the original lane, which is the lane in which the own vehicle was traveling at the start of the lane change support, and the target lane adjacent to the original lane in the lane change direction. Equipped with means (S19)
The target trajectory calculation means is
At the start of the lane change support, the first calculation means (S13, S14) for calculating the target trajectory of the own vehicle from the start to the completion of the lane change support, and
When it is determined by the boundary crossing determination means that the own vehicle has crossed the boundary, the second calculation means (S22, S23) for calculating the target trajectory of the own vehicle from that point to the completion of the lane change support are used. Have and
The support control means
Until it is determined that the own vehicle has crossed the boundary, the steering of the steering wheels is controlled so that the own vehicle travels along the target trajectory calculated by the first calculation means, and the own vehicle crosses the boundary. After it is determined that the vehicle has straddled, the steering of the steering wheels is controlled so that the own vehicle travels along the target trajectory calculated by the second calculation means (S15 to S18). ..

In the present invention, the lane recognition means recognizes a lane based on an image of a camera that captures the front of the own vehicle, and detects the relative positional relationship of the own vehicle with respect to the lane. A lane is, for example, an area defined by a white line. Therefore, by recognizing the lane, it is possible to determine the target track on which the own vehicle travels. The target track calculation means calculates a target track that causes the own vehicle to change lanes toward the target lane based on the relative positional relationship of the own vehicle with respect to the lane. Then, the support control means controls the steering of the steering wheels so that the own vehicle travels along the target trajectory.

If you try to complete the lane change support by using the target track calculated before the start of the lane change as it is, you may not be able to move your vehicle to the proper position in the target lane. Therefore, the present invention includes a boundary straddling determination means. The boundary crossing determination means determines whether or not the own vehicle straddles the boundary between the original lane, which is the lane in which the own vehicle was traveling at the start of the lane change support, and the target lane adjacent to the original lane in the lane change direction. judge.

The target trajectory calculation means includes a first calculation means and a second calculation means. The first calculation means calculates the target trajectory of the own vehicle from the start to the completion of the lane change support at the start of the lane change support. Further, the second calculation means calculates the target trajectory of the own vehicle from that time until the completion of the lane change support when the own vehicle is determined to have crossed the boundary by the boundary crossing determination means.

The assist control means controls the steering of the steering wheels so that the own vehicle travels along the target trajectory calculated by the first calculation means until it is determined that the own vehicle has crossed the boundary, and the own vehicle After it is determined that the vehicle has crossed the boundary, the steering of the steering wheels is controlled so that the own vehicle travels along the target trajectory calculated by the second calculation means.

Therefore, the target trajectory will be calculated again during the lane change support. In this case, since the final target position can be detected accurately by the lane recognition means, the second calculation means can more appropriately calculate the target trajectory. Therefore, by controlling the steering of the operating wheels based on the properly calculated target trajectory, it is possible to properly change the lane of the own vehicle to the target lane.

A feature of one aspect of the present invention is
The first calculation means sets a target lane change time, which is a target time from the start to the completion of the lane change support, and the elapsed time from the start of the lane change support of the own vehicle based on the target lane change time. It is configured to calculate the target trajectory function representing the target lateral position, which is the target position in the lane width direction of the own vehicle according to the time, as the target trajectory.
Based on the target lane change time, the second calculation means sets a target lateral position, which is a target position in the lane width direction of the own vehicle according to the elapsed time after it is determined that the own vehicle has crossed the boundary. It is configured to calculate the represented target orbit function as the target orbit.

In one aspect of the present invention, the first calculation means sets a target lane change time, which is a target time from the start to the completion of the lane change support. This target lane change time is set, for example, according to the distance in the lane width (road width) direction in which the own vehicle is moved from the start position of the lane change support to the final target position, the longer the distance, the longer the time. It is good. Based on the target lane change time, the first calculation means obtains a target trajectory function representing a target lateral position which is a target position in the lane width direction of the own vehicle according to the elapsed time from the start of the lane change support of the own vehicle. Calculate as the target trajectory.

In addition, the second calculation means represents a target lateral position which is a target position in the lane width direction of the own vehicle according to the elapsed time after it is determined that the own vehicle has crossed the boundary based on the target lane change time. Calculate the target trajectory function as the target trajectory. Therefore, the target trajectory function can be recalculated based on the relative position of the own vehicle with respect to the lane detected by the lane recognition means when it is determined that the own vehicle has crossed the boundary, and the target is highly accurate. The orbital function is obtained.

The assist control means controls the steering of the steering wheels so that the lateral position, which is the position in the lane width direction of the own vehicle, becomes the target lateral position. As a result, the lateral position of the own vehicle can be controlled by the elapsed time, and the own vehicle can be changed lanes on a predetermined track.

A feature of one aspect of the present invention is
In the second calculation means, the remaining time, which is the difference between the target lane change time and the time from the start of the lane change support until the own vehicle is determined to have crossed the boundary, is preset. If it is less than the lower limit, it is configured to increase the target lane change time.

During lane change support, the time it takes for the vehicle to be determined to have crossed the boundary may be longer than expected due to some disturbance. In such a case, the remaining time, which is the difference between the target lane change time and the time from the start of the lane change support until it is determined that the own vehicle has crossed the boundary, becomes short. In that case, it becomes impossible to properly support the lane change toward the final target position. Therefore, when the remaining time is less than the preset lower limit value, the second calculation means modifies the target lane change time in the direction of increasing. As a result, an appropriate target trajectory function can be calculated, and the own vehicle can be appropriately changed lanes.

A feature of one aspect of the present invention is
The support control means
Based on the target trajectory function calculated by the first calculation means or the second calculation means, the target lateral position (y *) of the own vehicle at the present time and the target of the motion state in the lane width direction of the own vehicle at the present time. The target lateral state amount calculating means (S15) for sequentially calculating the target lateral state amount representing the target lateral motion state amount (vy *, ay *) which is a value, and
The vehicle speed of the own vehicle at the present time is sequentially acquired, and the target yaw state amount (Cu *, θy *), which is the target value for the motion of changing the direction of the own vehicle at the present time, is based on the vehicle speed and the target lateral motion state amount. , Γ *), and the target yaw state quantity calculation means (S16),
It is provided with steering control means (S17, S18) for controlling the steering of the steering wheels based on the target lateral position and the target yaw state amount.

In one aspect of the present invention, the support control means includes a target lateral state amount calculation means, a target yaw state amount calculation means, and a steering control means. The target lateral state quantity calculating means determines the current target lateral position of the own vehicle and the current moving state in the lane width direction of the own vehicle based on the target trajectory function calculated by the first calculating means or the second calculating means. The target lateral state amount representing the target lateral motion state amount, which is the target value, is sequentially calculated.

The lateral motion state quantity represents, for example, the speed or acceleration of the own vehicle in the lane width direction. For example, by differentiating the target trajectory function with respect to time, the target lateral speed (speed in the lane width direction) of the own vehicle at that time can be obtained, and for example, the target trajectory function can be differentiated second-order with respect to time. Therefore, the target lateral acceleration (acceleration in the lane width direction) of the own vehicle at that time can be acquired. Therefore, the target lateral state quantity can be calculated using the target orbit function.

In addition, if the vehicle speed of the own vehicle is known, it is possible to calculate the target yaw state amount, which is a target value for the movement (movement to change the direction of the own vehicle) required to obtain the target lateral movement state amount of the own vehicle. .. Therefore, the target yaw state amount calculation means sequentially calculates the target yaw state amount, which is a target value related to the motion of changing the direction of the own vehicle at the present time, based on the vehicle speed and the target lateral motion state amount.

The steering control means controls the steering of the steering wheels based on the target lateral position and the target yaw state amount. That is, the steering control means controls the steering of the steering wheels so that the lateral position of the own vehicle becomes the target lateral position and the state amount for changing the direction of the own vehicle becomes the target yaw state amount.

Therefore, according to one aspect of the present invention, it is possible to smoothly change lanes reflecting the driver's accelerator operation (change in vehicle speed).

A feature of one aspect of the present invention is
The first calculation means is
When the initial lateral state amount representing the lateral position of the own vehicle with respect to the original lane and the lateral motion state amount which is the motion state in the lane width direction when the lane change support is started, and the lane change support are completed. Based on the final target lateral state amount representing the target lateral position and the target lateral motion state amount of the own vehicle with respect to the original lane and the target lane change time, the self according to the elapsed time from the start of the lane change support. It is configured to calculate a target trajectory function that represents the target lateral position, which is the target position in the lane width direction of the vehicle.
The second calculation means is
When it is determined that the own vehicle crosses the boundary, at least one of the lateral position of the own vehicle with respect to the target lane and the target lateral position calculated by the target lateral state amount calculating means, and the own vehicle The target lane when it is determined that the own vehicle has crossed the boundary based on at least one of the lateral motion state amount and the target lateral motion state amount calculated by the target lateral motion state amount calculating means. In addition to calculating the set lateral state amount at the time of straddling, which represents the set lateral position and the set lateral motion state amount of the own vehicle with respect to
The final target lateral state amount representing the target lateral position and the target lateral motion state amount of the own vehicle with respect to the target lane when the straddling set lateral state amount, the lane change support is completed, and the target lane change time. Based on, it is configured to calculate a target trajectory function representing a target lateral position which is a target position in the lane width direction of the own vehicle according to the elapsed time after it is determined that the own vehicle has crossed the boundary. It is in that.

In one aspect of the present invention, the first calculation means is the own vehicle according to the elapsed time from the start of the lane change support based on the initial lateral state amount, the final target lateral state amount, and the target lane change time. Calculates a target trajectory function that represents the target lateral position, which is the target position in the lane width direction of.

This initial lateral state amount represents the lateral position of the own vehicle with respect to the original lane when the lane change support is started and the lateral motion state amount which is the motion state in the lane width direction. Further, the final target lateral state amount represents the target lateral position of the own vehicle with respect to the original lane and the target lateral motion state amount when the lane change support is completed. The target lane change time represents the target time from the start to the completion of the lane change support. The lateral motion state amount represents, for example, the speed or acceleration detected value in the lane width direction of the own vehicle, and the target lateral motion state amount represents the speed or acceleration target value in the lane width direction of the own vehicle. .. The lateral position of the own vehicle and the lateral motion state amount of the own vehicle are acquired from the relative positional relationship of the own vehicle with respect to the lane detected by the lane recognition means.

On the other hand, the second calculation means responds to the elapsed time after it is determined that the own vehicle has crossed the boundary based on the set lateral state amount at the time of straddling, the final target lateral state amount, and the target lane change time. Calculates a target track function that represents the target lateral position, which is the target position in the lane width direction of the own vehicle.

The set lateral state amount at the time of straddling represents the set lateral position of the own vehicle and the set lateral motion state amount with respect to the target lane when it is determined that the own vehicle has crossed the boundary. The lateral state amount set at the time of straddling is determined to be at least one of the lateral position and the target lateral position of the own vehicle with respect to the target lane when the own vehicle is determined to have crossed the boundary, and the own vehicle is determined to have crossed the boundary. It is calculated based on at least one of the lateral motion state amount of the own vehicle and the target lateral motion state amount at that time.

Therefore, when the own vehicle crosses the boundary, it is possible to calculate a target trajectory function that smoothly connects the lateral state amount or the target lateral state amount of the own vehicle up to that point. As a result, the own vehicle can be changed lanes more smoothly.

A feature of one aspect of the present invention is
As the target yaw state amount, the target yaw state amount calculating means has a target yaw angle which is a target value of a horizontal angle of the own vehicle facing the lane and a target yaw rate which is a target value of the yaw rate of the own vehicle. , And at least one of the target curvatures, which is the curvature of the target trajectory, is configured to be calculated.

According to the present invention, the target yaw state amount can be appropriately calculated, and the own vehicle can be appropriately changed lanes. For example, the target yaw angle can be calculated by the inverse sine of the target lateral speed divided by the vehicle speed. In addition, the target yaw rate can be calculated by dividing the target lateral acceleration by the vehicle speed. Further, the target curvature can be calculated by dividing the target lateral acceleration by the square value of the vehicle speed.

A feature of one aspect of the present invention is
The lane recognition means outputs lateral position information indicating a position in the lane width direction of the own vehicle with respect to the center line of the lane in which the own vehicle is traveling to the boundary straddling determination means.
When the boundary straddling determination means detects that the lateral position information output by the lane recognition means has switched from the lateral position information related to the original lane to the lateral position information related to the target lane, the own vehicle determines the boundary. It was configured to determine that it straddled.

In one aspect of the present invention, the lane recognition means outputs lateral position information indicating a position in the lane width direction of the own vehicle with respect to the center line of the lane in which the own vehicle is traveling to the boundary straddling determination means. Since the lateral position information represents the position of the own vehicle in the lane width direction with respect to the center line of the lane, information for identifying which direction the own vehicle is located on the left or right side with respect to the center line is also included. When the own vehicle crosses the boundary and enters the adjacent lane and the lateral position information is switched, the left-right direction of the own vehicle represented by the lateral position information is reversed. Therefore, by using the information indicating the left-right direction, it is possible to determine whether or not the own vehicle has crossed the lane boundary.

Therefore, when the boundary crossing determination means detects that the lateral position information output by the lane recognition means has switched from the lateral position information related to the original lane to the lateral position information related to the target lane, the own vehicle crosses the boundary. Judge as. Therefore, it is possible to appropriately determine whether or not the own vehicle has crossed the boundary.

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

It is a schematic block diagram of the lane change support device which concerns on embodiment of this invention. It is a top view which showed the mounting position of a peripheral sensor and a camera sensor. It is a figure for demonstrating lane-related vehicle information. It is a figure for demonstrating the operation of a blinker lever. It is a flowchart which shows the steering support control routine which concerns on embodiment. It is a figure which shows the track of own vehicle. It is a figure which shows the target orbit function. It is a figure which shows the target orbit function. It is a figure which shows the target orbit function. It is a figure which shows the target orbit function. It is a top view of the road which shows the modification of the boundary white line crossing judgment. It is a flowchart which shows the steering support control routine which concerns on modification 1. It is a flowchart which shows the steering support control routine which concerns on modification 2.

Hereinafter, the lane change support device according to the embodiment of the present invention will be described with reference to the drawings.

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

These ECUs are electric control units (Electric Control Units) including a microcomputer as a main unit, and are connected to each other via a CAN (Controller Area Network) 100 so that information can be transmitted and received. In the present specification, the microcomputer includes a CPU, ROM, RAM, non-volatile memory, interface I / F, and the like. The CPU realizes various functions by executing instructions (programs, routines) stored in ROM. Some or all of these ECUs may be integrated into one ECU.

Further, the CAN 100 includes a plurality of types of vehicle state sensors 80 for detecting the vehicle state and a plurality of types of driving operation state sensors 90 for detecting the driving operation state. The vehicle condition sensor 80 includes, for example, a vehicle speed sensor that detects the traveling speed of the vehicle, a front-rear G-sensor that detects the acceleration in the front-rear direction of the vehicle, a lateral G-sensor that detects the lateral acceleration of the vehicle, and a yaw rate of the vehicle. It is a yaw rate sensor to detect.

The driving operation state sensor 90 detects an accelerator operation amount sensor that detects the operation amount of the accelerator pedal, a brake operation amount sensor that detects the operation amount of the brake pedal, a brake switch that detects the presence or absence of operation of the brake pedal, 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 the shift position of a transmission.

Information (referred to as sensor information) detected by the vehicle state sensor 80 and the driving operation state sensor 90 is transmitted to the CAN 100. In each ECU, the sensor information transmitted to the CAN 100 can be appropriately used. The sensor information is information on a sensor connected to a specific ECU, and may be transmitted from the specific ECU to the CAN 100. For example, the accelerator operation amount sensor may be connected to the engine ECU 50. In this case, the sensor information representing the accelerator operation amount is transmitted from the engine ECU 50 to the CAN 100. For example, the steering angle sensor may be connected to the steering ECU 40. In this case, the sensor information indicating the steering angle is transmitted from the steering ECU 40 to the CAN 100. The same applies to other sensors. Further, a configuration may be adopted in which sensor information is exchanged by direct communication between specific ECUs without interposing the CAN 100.

The driving support ECU 10 is a central control device that assists the driver in driving, and performs lane change support control, lane keeping support control, and follow-up inter-vehicle distance control. As shown in FIG. 2, the driving support ECU 10 is connected to the center front peripheral sensor 11FC, the right front peripheral sensor 11FR, the left front peripheral sensor 11FL, the right rear peripheral sensor 11RR, and the left rear peripheral sensor 11RL. The peripheral sensors 11FC, 11FR, 11FL, 11RR, and 11RL are radar sensors, and basically have the same configuration as each other except that their detection areas are different from each other. Hereinafter, when it is not necessary to individually distinguish each peripheral sensor 11FC, 11FR, 11FL, 11RR, 11RL, they are referred to as peripheral sensors 11.

The peripheral sensor 11 includes a radar transmission / reception unit and a signal processing unit (not shown), and the radar transmission / reception unit emits radio waves in the millimeter wave band (hereinafter, referred to as “millimeter wave”) and has a radiation range. It receives millimeter waves (ie, reflected waves) reflected by a three-dimensional object (eg, another vehicle, pedestrian, bicycle, building, etc.) existing inside. The signal processing unit is based on the phase difference between the transmitted millimeter wave and the received reflected wave, the attenuation level of the reflected wave, the time from the transmission of the millimeter wave to the reception of the reflected wave, and the like. Information (hereinafter referred to as peripheral information) representing the distance to the vehicle, the relative speed between the own vehicle and the three-dimensional object, the relative position (direction) of the three-dimensional object with respect to the own vehicle, etc. is acquired every predetermined time, and the driving support ECU 10 Supply to. From this peripheral information, it is possible to detect the front-rear direction component and the lateral direction component in the distance between the own vehicle and the three-dimensional object, and the front-rear direction component and the lateral direction component in the relative speed between the own vehicle and the three-dimensional object.

As shown in FIG. 2, the center front peripheral sensor 11FC is provided in the front center portion of the vehicle body and detects a three-dimensional object existing in the front region of the own vehicle. The right front peripheral sensor 11FR is provided at the right front corner of the vehicle body and mainly detects a three-dimensional object existing in the right front region of the own vehicle, and the left front peripheral sensor 11FL is provided at the left front corner of the vehicle body and is mainly used. Detects a three-dimensional object existing in the left front area of the own vehicle. The right rear peripheral sensor 11RR is provided at the right rear corner of the vehicle body and mainly detects a three-dimensional object existing in the right rear region of the own vehicle, and the left rear peripheral sensor 11RL is provided at the left rear corner of the vehicle body. , Detects three-dimensional objects mainly in the left rear region of the own vehicle.

The peripheral sensor 11 is a radar sensor in the present embodiment, but other sensors such as a clearance sonar and a rider sensor can be adopted instead.

Further, a camera sensor 12 is connected to the driving support ECU 10. The camera sensor 12 includes a camera unit and a lane recognition unit that analyzes image data obtained by taking a picture of the camera unit and recognizes a white line on a road. The camera sensor 12 (camera unit) captures the scenery in front of the own vehicle. The camera sensor 12 (lane recognition unit) repeatedly supplies the recognized white line information to the operation support ECU 10 at a predetermined calculation cycle.

The camera sensor 12 recognizes the lane representing the area defined by the white line, and can detect the relative positional relationship of the own vehicle with respect to the lane based on the positional relationship between the white line and the own vehicle. Here, the position of the own vehicle is the position of the center of gravity of the own vehicle. Further, the lateral position of the own vehicle, which will be described later, represents the position of the center of gravity of the own vehicle in the lane width direction, and the lateral speed of the own vehicle represents the speed of the center of gravity of the own vehicle in the lane width direction. The lateral acceleration represents the acceleration of the position of the center of gravity of the own vehicle in the lane width direction. These are obtained by the relative positional relationship between the white line detected by the camera sensor 12 and the own vehicle. In the present embodiment, the position of the own vehicle is set as the center of gravity position, but the position is not necessarily limited to the center of gravity position, and a predetermined specific position (for example, the center position in a plan view) may be adopted. it can.

As shown in FIG. 3, the camera sensor 12 sets the lane center line CL, which is the center position in the width direction of the left and right white lines WL in the lane in which the own vehicle is traveling. This lane center line CL is used as a target traveling line in lane keeping support control described later. Further, the camera sensor 12 calculates the curvature Cu of the curve of the lane center line CL.

Further, the camera sensor 12 calculates the position and orientation of the own vehicle in the lane defined by the left and right white lines WL. For example, as shown in FIG. 3, the camera sensor 12 has a distance Dy (m) in the lane width direction between the center of gravity point P of the own vehicle C and the lane center line CL, that is, the own vehicle C is the lane center line CL. The distance Dy deviated from the lane width direction is calculated. This distance Dy is called a lateral deviation Dy. Further, in the camera sensor 12, the angle formed by the direction of the lane center line CL and the direction of the own vehicle C, that is, the direction of the own vehicle C with respect to the direction of the lane center line CL is horizontal. Calculate the offset angle θy (rad). This angle θy is called a yaw angle θy. When the lane is curved, the lane center line CL is also curved, so the yaw angle θy is an angle deviated from the curved lane center line CL in the direction in which the own vehicle C is facing. Represents. Hereinafter, information (Cu, Dy, θy) representing the curvature Cu, the lateral deviation Dy, and the yaw angle θy will be referred to as lane-related vehicle information. The lane-related vehicle information (Cu, Dy, θy) specifies the left-right direction with respect to the lane center line CL by a sign (positive or negative).

Further, the camera sensor 12 includes not only the lane of the own vehicle but also adjacent lanes, the type of detected white line (solid line, broken line), the distance between the adjacent left and right white lines (lane width), the shape of the white line, and the like. Information on the white line is also supplied to the operation support ECU 10 at a predetermined calculation cycle. If the white line is a solid line, vehicles are prohibited from changing lanes across the white line. On the other hand, if the white line is a broken line (white line formed intermittently at regular intervals), the vehicle is allowed to change lanes across the white line. Such lane-related vehicle information (Cu, Dy, θy) and information on the white line are collectively referred to as lane information.

In the present embodiment, the camera sensor 12 calculates lane-related vehicle information (Cu, Dy, θy), but instead, the driving support ECU 10 analyzes the image data output by the camera sensor 12. You may try to acquire lane information.

Further, since the camera sensor 12 can detect a three-dimensional object existing in front of the own vehicle based on the image data, the surrounding information in front may be acquired by calculation in addition to the lane information. In this case, for example, the peripheral information acquired by the central front peripheral sensor 11FC, the right front peripheral sensor 11FR, and the left front peripheral sensor 11FL is combined with the peripheral information acquired by the camera sensor 12 to obtain the detection accuracy. It is preferable to provide a synthesis processing unit (not shown) that generates high front peripheral information, and supply the peripheral information generated by this synthesis processing unit to the driving support ECU 10 as peripheral information in front of the own vehicle.

A buzzer 13 is connected to the driving support ECU 10. The buzzer 13 sounds by inputting a buzzer ringing signal from the driving support ECU 10. The driving support ECU 10 sounds the buzzer 13 when notifying the driver of the driving support status and when calling attention to the driver.

In the present embodiment, the buzzer 13 is connected to the driving support ECU 10, but is connected to another ECU, for example, a notification ECU (not shown) provided exclusively for notification, and is sounded by the notification ECU. It may be configured as follows. In this case, the driving support ECU 10 transmits a buzzer sounding command to the notification ECU.

Further, instead of or in addition to the buzzer 13, a vibrator for transmitting a vibration for calling attention to the driver may be provided. For example, a vibrator is provided on the steering wheel and vibrates the steering wheel to alert the driver.

The driving support ECU 10 informs the peripheral information supplied from the peripheral sensor 11, the lane information obtained based on the white line recognition of the camera sensor 12, the vehicle state detected by the vehicle state sensor 80, and the driving operation state sensor 90. Based on the detected driving operation state and the like, lane change support control, lane keeping support control, and follow-up vehicle-to-vehicle distance control are performed.

A setting operator 14 operated by a driver is connected to the driving support ECU 10. The setting operation device 14 is an operation device for setting whether or not to implement each of the lane change support control, the lane keeping support control, and the following inter-vehicle distance control. The operation support ECU 10 inputs the setting signal of the setting operation device 14 to determine whether or not each control is executed. In this case, if the implementation of the following inter-vehicle distance control is not selected, the lane change support control and the lane keeping support control are automatically set so as not to be implemented. If the implementation of lane keeping support control is not selected, the lane change support control is automatically set so as not to be implemented.

In addition, the setting operation device 14 also has a function of inputting a parameter or the like representing a driver's preference when performing the above control.

The electric power steering ECU 20 is a control device for the 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 the motor driver 21. The motor driver 21 is connected to the steering motor 22. The steering motor 22 is incorporated in a "steering mechanism including a steering wheel, a steering shaft connected to the steering handle, a steering gear mechanism, and the like" of a vehicle (not shown). The EPS / ECU 20 detects the steering torque input to the steering handle (not shown) by the driver by the steering torque sensor provided on the steering shaft, and controls the energization of the motor driver 21 based on the steering torque. It drives the steering motor 22. Steering torque is applied to the steering mechanism by driving the assist motor to assist 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 steering assist torque given to lighten the steering operation (steering operation) of the driver described above, and the steering mechanism is given by a steering command from the driving support ECU 10 without requiring the steering operation of the driver. Represents the torque applied to.

The meter ECU 30 is connected to a display 31 and left and right turn signal 32s (meaning turn signal lamps, sometimes called 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, when the meter ECU 30 receives 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 the screen specified by the display command. As the display unit 31, a head-up display (not shown) can be used instead of or in addition to the multi-information display. When a head-up display is adopted, it is preferable to provide a dedicated ECU for controlling the display of the head-up display.

Further, the meter ECU 30 is provided with a blinker drive circuit (not shown), and when a blinker blinking command is received via the CAN 100, the blinker 32 in the direction (right, left) specified by the blinker blinking command is blinked. Let me. Further, while the blinker 32 is blinking, the meter ECU 30 transmits blinker blinking information indicating that the blinker 32 is in the blinking state to the CAN 100. Therefore, in other ECUs, the blinking state of the blinker 32 can be grasped.

The steering ECU 40 is connected to the turn signal lever 41. The blinker lever 41 is an operator for operating (blinking) the blinker 32, and is provided on the steering column. The blinker lever 41 is provided so as to be swingable with two steps of operation strokes around the support shaft in each of the clockwise operation direction and the counterclockwise operation direction.

The blinker lever 41 of the present embodiment is also used as an actuator for which the driver requests lane change support control. As shown in FIG. 4, the blinker lever 41 is the first stroke, which is a position rotated by a first angle θW1 from the neutral position PN in each of the clockwise operation direction and the counterclockwise operation direction about the support shaft O. It is configured to be selectively operable at the position P1L (P1R) and the second stroke position P2L (P2R) which is a position rotated by a second angle θW2 (> θW1) from the neutral position PN. At the first stroke position P1L (P1R), the blinker 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 if the lever operating force is released, The state is held by the lock mechanism. Further, when the turn signal lever 41 is held at the second stroke position P2L (P2R) and the steering handle is rotated in the reverse direction to return to the neutral position, 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 the position is returned to the neutral position PN.

The blinker lever 41 is turned on only when the first switch 411L (411R) is tilted to the first stroke position P1L (P1R) and when it is tilted to the second stroke position P2L (P2R). It is equipped with a second switch 412L (412R).

The steering ECU 40 detects the operating state of the blinker lever 41 based on the states of the first switch 411L (411R) and the second switch 412L (412R), and the blinker lever 41 moves to the first stroke position P1L (P1R). In each of the state of being tilted to the second stroke position P2L (P2R) and the state of being tilted to the second stroke position P2L (P2R), a blinker blinking command including information indicating the operation direction (left and right) is transmitted to the meter ECU 30. ..

Further, the steering ECU 40 has detected that the blinker 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 longer. In this case, a lane change support request signal including information indicating the operation direction (left and right) is output to the driving support ECU 10. Therefore, if the driver wants to receive lane change assistance during driving, the driver may tilt the blinker lever 41 to the first stroke position P1L (P1R) in the lane change direction and hold the turn signal lever 41 for a set time or longer. Such an operation is called a lane change support request operation.

In the present embodiment, the blinker lever 41 is also used as an operator for requesting lane change support by the driver, but instead, a dedicated lane change support request operator may be provided on the steering wheel or the like. ..

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

The brake ECU 60 is connected to the 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 pedaling force of a brake pedal and a friction brake mechanism 62 provided on the left, 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 in the brake caliper 62b in response to an instruction from the brake ECU 60, and operates the wheel cylinder by the hydraulic pressure to press the brake pad against the brake disc 62a and cause friction. Generates braking force. Therefore, the brake ECU 60 can control the braking force of the own vehicle by controlling the brake actuator 61.

The navigation ECU 70 includes a GPS receiver 71 that receives GPS signals for detecting the current position of the own vehicle, a map database 72 that stores map information, and a touch panel (touch panel display) 73. The navigation ECU 70 identifies the current position of the own vehicle based on the GPS signal, performs various arithmetic processes based on the position of the own vehicle and the map information stored in the map database 72, and uses the touch panel 73. To provide route guidance.

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 CL of each lane, and the like). In addition, the road information includes road type information and the like that can distinguish whether or not the road is a motorway.

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

<Lane maintenance support control (LTA)>
The lane keeping support control applies steering torque to the steering mechanism to support the driver's steering operation so that the position of the own vehicle is maintained near the target driving line in the "lane in which the own vehicle is traveling". It is a control to do. In the present embodiment, the target traveling 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 can also be adopted.

Hereinafter, lane keeping support control will be referred to as LTA (lane tracing assist). Although LTA is called by various names, it is well known by itself (for example, JP-A-2008-195402, JP-A-2009-190464, JP-A-2010-6279, and Patent No. 434,210, etc.). Therefore, it will be briefly described below.

The operation support ECU 10 executes the LTA when the LTA is requested by the operation of the setting operation device 14. When LTA is required, the driving support ECU 10 sets the target steering angle θlta * to a predetermined calculation cycle according to the following equation (1) based on the above-mentioned lane-related vehicle information (Cu, Dy, θy). And calculate.

θlta * = Klta1, Cu + Klta2, θy + Klta3, Dy + Klta4, ΣDy
… (1)

Here, Klta1, Klta2, Klta3, and Klta4 are control gains. The first term on the right side is a steering angle component that acts like a feed forward, which is determined according to the curvature Cu of the road. The second term on the right side is a steering angle component that acts as a feedback so as to reduce the yaw angle θy (to reduce the deviation of the direction of the own vehicle with respect to the lane center line CL). That is, it is a steering angle component calculated by feedback control with the target value of the yaw angle θy set to zero. The third term on the right side is a steering angle component that acts as a feedback so as to reduce the lateral deviation Dy, which is the deviation (positional deviation) of the position of the own vehicle in the lane width direction with respect to the lane center line CL. That is, it is a steering angle component calculated by feedback control with the target value of the lateral deviation Dy set to zero. The fourth term on the right side is a steering angle component that acts as a feedback so as to reduce the integral value ΣDy of the lateral deviation Dy. That is, it is a steering angle component calculated by feedback control with the target value of the integrated value ΣDy as zero.

For example, when the lane center line CL is curved to the left, when the own vehicle is laterally displaced to the right with respect to the lane center line CL, and when the own vehicle is right with respect to the lane center line CL. When facing in the direction, the target steering angle θlta * in the left direction is set. Further, when the lane center line CL is curved to the right, when the own vehicle is laterally displaced to the left with respect to the lane center line CL, and when the own vehicle is left with respect to the lane center line CL. When facing in the direction, the target steering angle θlta * in the right direction is set. Therefore, when calculating the above equation (1), the calculation may be performed using a code corresponding to the left-right direction.

The driving support ECU 10 outputs a command signal representing the target steering angle θlta *, which is the calculation result, to the EPS / ECU 20. The EPS / ECU 20 drives and controls the steering motor 22 so that the steering angle follows the target steering angle θlta *. In the present embodiment, the driving support ECU 10 outputs a command signal representing the target steering angle θlta * to the EPS / ECU 20, but calculates the target torque at which the target steering angle θlta * is obtained, which is the calculation result. A command signal representing the target torque may be output to the EPS / ECU 20.
The above is the outline of LTA.

<Following inter-vehicle distance control (ACC)>
When there is a preceding vehicle traveling in front of the own vehicle, the following inter-vehicle distance control maintains the inter-vehicle distance between the preceding vehicle and the own vehicle at a predetermined distance based on the surrounding information. This is a control in which the vehicle is made to follow the preceding vehicle, and when the preceding vehicle does not exist, the own vehicle is driven at a constant speed at the set vehicle speed. Hereinafter, following vehicle-to-vehicle distance control is referred to as ACC (adaptive cruise control). The ACC itself is well known (see, for example, Japanese Patent Application Laid-Open No. 2014-148293, Japanese Patent Application Laid-Open No. 2006-315491, Japanese Patent No. 4172434, Japanese Patent No. 4929777, etc.). Therefore, it will be briefly described below.

The operation support ECU 10 executes the ACC when the ACC is requested by the operation of the setting operation device 14. When the ACC is required, the driving support ECU 10 selects the tracking target vehicle based on the peripheral information supplied from the peripheral sensor 11. For example, the driving support ECU 10 determines whether or not another vehicle exists in a predetermined tracking target vehicle area.

When another vehicle exists in the tracking target vehicle area for a predetermined time or longer, the driving support ECU 10 selects the other vehicle as the tracking target vehicle and sets the target acceleration so that the own vehicle follows the tracking target vehicle. Set. Further, the driving support ECU 10 determines the set vehicle speed and the detected vehicle speed (vehicle speed detected by the vehicle speed sensor) so that the vehicle speed of the own vehicle matches the set vehicle speed when there is no other vehicle in the tracking target vehicle area. Set the target acceleration based on.

The driving support ECU 10 uses the engine ECU 50 to control the engine actuator 51 so that the acceleration of the own vehicle matches the target acceleration, and also controls the brake actuator 61 using the brake ECU 60 as needed.
When the driver operates the accelerator during ACC, the accelerator operation is prioritized and the acceleration of the own vehicle is set.
The above is the outline of ACC.

<Lane change support control (LCA)>
The lane change support control monitors the surroundings of the own vehicle and determines that it is possible to change lanes safely. Then, while monitoring the surroundings of the own vehicle, the lane adjacent to the lane in which the own vehicle is currently traveling It is a control that supports the driver's steering operation (lane change operation) by applying steering torque to the steering mechanism so as to move to. Therefore, according to the lane change support control, it is possible to change the lane in which the own vehicle travels without requiring the driver's steering operation (steering wheel operation). Hereinafter, lane change support control will be referred to as LCA (lane change assist).

Like the LTA, the LCA is a control of the lateral position of the own vehicle with respect to the lane, and is implemented in place of the LTA when a lane change support request is received during the implementation of the LTA and the ACC. Hereinafter, LTA and LCA are collectively referred to as steering support control, and the state of steering support control is referred to as steering support control state.

FIG. 5 shows a steering support control routine executed by the driving support ECU 10. The steering support control routine is executed when the conditions for permitting execution of LTA are satisfied. The LTA execution permission conditions are that the implementation of LTA is selected by the setting actuator 14, that ACC is executed, that the white line can be recognized by the camera sensor 12, and the like.

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

Subsequently, the driving support ECU 10 determines in step S12 whether or not the LCA start condition is satisfied.

The LCA start condition is satisfied, for example, when all of the following conditions are satisfied.
1. 1. The lane change support request operation is detected.
2. 2. Implementation of LCA is selected by the setting actuator 14.
3. 3. The white line in the turn signal operation direction (the white line that is the boundary between the original lane and the target lane) is a broken line.
4. The result of determining whether or not LCA can be carried out for peripheral monitoring is possible (the peripheral sensor 11 has not detected any obstacles (other vehicles, etc.) that hinder the lane change, and it is determined that the lane can be changed safely. ).
5. The road is a motorway (the road type information acquired from the navigation ECU 70 represents a motorway).
6. The vehicle speed of your vehicle is within the LCA permitted vehicle speed range permitted by LCA.
For example, the condition 4 is satisfied when the inter-vehicle distance between the own vehicle and another vehicle traveling in the target lane is appropriately secured in consideration of the relative speed.
The LCA start condition is not limited to these conditions and can be set arbitrarily.

If the LCA start condition is not satisfied, the operation support ECU 10 returns the process to step S11 to continue the execution of the LTA.

If the LCA start condition is satisfied while the LTA is being implemented (S12: Yes), the operation support ECU 10 implements the LCA instead of the LTA. At the start of the LCA, the operation support ECU 10 transmits an LCA start guidance display command to the meter ECU 30. As a result, the LCA start guidance is displayed on the display 31.

At the start of the LCA, the operation support ECU 10 first performs the initialization process of the target trajectory calculation parameter in step S13. Here, the target trajectory of the LCA will be described.

When carrying out LCA, the driving support ECU 10 calculates a target trajectory function that determines a target trajectory of the own vehicle. The target track is the width of the lane (called the target lane) in the direction of requesting lane change support adjacent to the original lane from the lane in which the vehicle is currently traveling (called the original lane) over the target lane change time. It is a trajectory that moves to the direction center position (referred to as the final target lateral position), and has a shape as shown in FIG. 6, for example.

As will be described later, the target track function is a function that calculates the target lateral position of the own vehicle corresponding to the elapsed time with the elapsed time from the start time of LCA as a variable with reference to the lane center line CL. Here, the lateral position of the own vehicle represents the position of the center of gravity of the own vehicle in the lane width direction (sometimes referred to as the lateral direction) with the lane center line CL as a reference (origin). Further, as will be described later, the lane center line CL, which is the reference for calculating the lateral position, is the lane center line CL in the original lane before the own vehicle crosses the white line that is the boundary between the original lane and the target lane. Yes, after the own vehicle crosses the white line that is the boundary between the original lane and the target lane, it is the lane center line CL in the target lane. Hereinafter, when the white line that is the boundary between the original lane and the target lane is specified, the white line is referred to as a boundary white line WLD.

The target lane change time is variably set in proportion to the distance (hereinafter referred to as the required lateral distance) for laterally moving the own vehicle from the initial position which is the start position of the LCA to the final target lateral position. When the lane width is generally 3.5 m, the target lane change time is set to, for example, 8.0 seconds. This example is a case where the own vehicle at the start of LCA is located in the lane center line CL of the original lane. If the lane width is, for example, 4.0 m, the target lane change time is set to a value according to the lane width, in this example, 9.1 seconds (= 8.0 x 4.0 / 3.5). Will be done.

Further, the target lane change time is such that when the lateral position of the own vehicle at the start of LCA is deviated to the lane change side from the lane center line CL of the original lane, the deviation amount (lateral deviation Dy) is larger. Set to decrease. On the contrary, when the lateral position of the own vehicle at the start of LCA is deviated from the lane center line CL of the original lane to the opposite lane change side, the target lane change time is the deviation amount (lateral deviation Dy). It is set to increase as the number increases. For example, if the deviation amount is 0.5 m, the increase / decrease adjustment amount of the target lane change time may be 1.14 seconds (= 8.0 × 0.5 / 3.5). The value for setting the target lane change time shown here is only an example, and an arbitrarily set value can be adopted.

In the present embodiment, the target lateral position y is calculated by the target trajectory function y (t) shown in the following equation (2). This target orbital function y (t) is a quintic function with the elapsed time t as a variable.

y (t) = c ₀ + c ₁ · t + c ₂ · t ² + c ₃ · t ³ + c ₄ · t ⁴ + c ₅ · t ⁵
... (2)
This target trajectory function y (t) is set to a function that smoothly moves the own vehicle to the final target position.

Here, the coefficients c ₀ , c ₁ , c ₂ , c ₃ , c ₄ , and c ₅ are the state of the own vehicle at the start of LCA (initial lateral state amount) and the target state of the own vehicle at the completion of LCA (final). It is determined by the target lateral state quantity).

For example, as shown in FIG. 7, the target track function y (t) is based on the lane center line CL of the lane (original lane) in which the own vehicle C is currently traveling, and is at the start time of LCA (target track). This is a function for calculating the target lateral position y (t) of the own vehicle C corresponding to the elapsed time t (sometimes referred to as the current time t) from the calculation time point). In FIG. 7, the lane is formed in a straight line, but as shown in FIG. 8, when the lane is formed in a curved line, the target track function y (t) is the lane center line formed in the curved line. This is a function for calculating the target lateral position of the own vehicle with respect to the lane center line CL with reference to CL.

As will be described later, the target track function y (t) is calculated again even after the own vehicle crosses the boundary white line WLD by LCA. The target track function y (t) in this case is switched to a function representing the target lateral position of the own vehicle C with reference to the lane center line CL of the target lane.

The parameters that determine the coefficients c ₀ , c ₁ , c ₂ , c ₃ , c ₄ , and c ₅ of the target trajectory function y (t) are the target trajectory calculation parameters. The target trajectory calculation parameters are the following seven (P1 to P7).
P1. The lateral position of the own vehicle with respect to the lane center line of the original lane when the LCA is started (called the initial lateral position).
P2. The lateral speed of the vehicle at the start of LCA (called the initial lateral speed).
P3. Lateral acceleration of the own vehicle when starting LCA (called initial lateral acceleration).
P4. The target lateral position of the own vehicle with respect to the lane center line of the original lane when the LCA is completed (called the final target lateral position).
P5. The lateral target speed of the vehicle when completing the LCA (called the final target lateral speed).
P6. Lateral target acceleration of the own vehicle when completing LCA (called final target lateral acceleration).
P7. Target lane change time, which is the target time for conducting LCA.
The lateral direction represents the width direction of the lane.

The camera sensor 12 outputs lane information related to each lane detected in front of the own vehicle, but the driving support ECU 10 outputs the lane information related to the lane in which the own vehicle is located when the steering support control is executed. Use lane information for the central line CL. The camera sensor 12 attaches identification information that can identify the lane information in which the own vehicle is located, and outputs lane information related to each lane. The driving support ECU 10 acquires lane information in the lane in which the own vehicle is traveling based on this identification information during the implementation of LCA. Therefore, at the start of LCA, lane information related to the original lane (lane-related vehicle information (Cu, Dy, θy), lane width, types of left and right white lines, etc.) is used.

The initial lateral position is set to a value equal to the lateral deviation Dy detected by the camera sensor 12 at the start of LCA. The initial lateral speed is obtained by multiplying the vehicle speed v detected by the vehicle speed sensor at the start of LCA by the sine value (sin (θy)) of the yaw angle θy detected by the camera sensor 12 (v · sin (θy). )) Is set. The initial lateral acceleration may be set to the derivative value of the above initial lateral velocity, but is preferably a value obtained by multiplying the yaw rate γ (rad / s) detected by the yaw rate sensor at the start of LCA by the vehicle speed v. It is preferable to set it to (v · γ). This is because when the yaw rate sensor is used, the change in the behavior of the own vehicle can be detected more quickly than when the camera sensor 12 is used. The initial lateral position, initial lateral velocity, and initial lateral acceleration are collectively referred to as an initial lateral state quantity.

Further, in the present embodiment, the lane width of the target lane is considered to be the same as the lane width of the original lane detected by the camera sensor 12. Therefore, the final target horizontal position is set to the same value as the lane width of the original lane (final target horizontal position = lane width of the original lane). Further, the values of the final target lateral velocity and the final target lateral acceleration are both set to zero. The final target lateral position, the final target lateral velocity, and the final target lateral acceleration are collectively referred to as the final target lateral state quantity.

As described above, the target lane change time is calculated by the lane width (the lane width of the original lane may be used) and the lateral deviation amount of the own vehicle at the start of LCA.
For example, the target lane change time len is calculated by the following equation (3).
tlen = Dini ・ A ・ ・ ・ (3)
Here, Dini is a required distance for laterally moving the own vehicle from the LCA start position (initial lateral position) to the LCA completion position (final target lateral position). Therefore, if the own vehicle is located in the lane center line CL of the original lane at the start of LCA, Dini is set to a value equal to the lane width, and when the own vehicle deviates from the lane center line CL of the original lane. Is a value obtained by adjusting the amount of deviation to the lane width. A is a constant representing the target time spent to move the own vehicle laterally by a unit distance, and is set to, for example, (8 sec / 3.5 m = 2.29 sec / m). In this example, for example, when the required distance Dini for moving the own vehicle in the lateral direction is 3.5 m, the target lane change time len is set to 8 seconds.

The constant A is not limited to the above value, and can be set arbitrarily. Further, for example, the setting operator 14 may be used so that the constant A can be selected in a plurality of ways according to the driver's preference. Further, the target lane change time may be a fixed value.

The initialization process of the target trajectory calculation parameters in step S13 includes these seven parameters (initial lateral position, initial lateral speed, initial lateral acceleration, final target lateral position, final target lateral speed, final target lateral acceleration, target lane change time). ) Is set as described above.

The operation support ECU 10 executes the initialization process of the target trajectory calculation parameter in step S13, and subsequently executes the derivation process of the target trajectory function in step S14. Specifically, the driving support ECU 10 has a coefficient c _{0 of} the target trajectory function y (t) represented by the equation (2) based on the initial lateral state amount, the final target lateral state amount, and the target lane change time. The target orbital function y (t) is determined by calculating c ₁ , c ₂ , c ₃ , c ₄ , and c ₅ .

From the target trajectory function y (t) expressed by the above equation (2), the lateral velocity y'(t) of the own vehicle can be expressed by the following equation (4), and the lateral acceleration y''(of the own vehicle. t) can be expressed by the following equation (5).
y'(t) = c ₁ + 2c ₂ · t + 3c ₃ · t ² + 4c ₄ · t ³ + 5c ₅ · t ⁴
... (4)
y'' (t) = 2c ₂ + 6c ₃・ t + 12c ₄・ t ² + 20c ₅・ t ³
... (5)

Here, the initial lateral position is y0, the initial lateral speed is by0, the initial lateral acceleration is ay0, the final target lateral position is y1, the final target lateral speed is by1, the final target lateral speed is ay1, and the lane width of the original lane is W. Then, the following relational expression is obtained based on the above target trajectory calculation parameters.
y (0) = c ₀ = y0 ... (6)
y'(0) = c ₁ = by0 ... (7)
y'' (0) = 2c ₂ = ay0 ... (8)
y (tlen) = c ₀ + c ₁・ tlen + c ₂・ tlen ² + c ₃・ tlen ³
＋ C ₄・ tlen ⁴ ＋ c ₅・ tlen ⁵ ＝ y1 ＝ W ・ ・ ・ (9)
y'(tlen) = c ₁ + 2c ₂・ tlen + 3c ₃・ tlen ²
+ 4c ₄ · tlen ³ + 5c ₅ · tlen ⁴ = by1 = 0 ・ ・ ・ (10)
y'' (tlen) = 2c ₂ + 6c ₃・ tlen + 12c ₄・ tlen ²
+ 20c ₅ · trend ³ = ay1 = 0 ... (11)

Therefore, the values of the coefficients c ₀ , c ₁ , c ₂ , c ₃ , c ₄ , and c ₅ of the target orbital function y (t) can be calculated from these six equations (6) to (11). Then, the target orbital function y (t) is calculated by substituting the calculated values of the coefficients c ₀ , c ₁ , c ₂ , c ₃ , c ₄ , and c ₅ into the equation (2). Further, at the same time as the calculation of the target trajectory function y (t), the driving support ECU 10 activates the timekeeping timer (initial value: zero) to start counting up the elapsed time t from the start of the LCA.

Subsequently, in step S15, the driving support ECU 10 calculates the target lateral state amount of the own vehicle at the present time. The target lateral state amount is the target lateral position which is the target value of the lateral position in the lane width direction of the own vehicle, the target lateral speed which is the target value of the speed (lateral speed) in the lane width direction of the own vehicle, and the own vehicle. It represents the target lateral acceleration, which is the target value of the acceleration (lateral acceleration) in the lane width direction. Lateral velocity and lateral acceleration may be collectively referred to as a lateral motion state amount, and target lateral velocity and target lateral acceleration may be collectively referred to as a target lateral motion state amount.

In this case, the driving support ECU 10 calculates the target lateral position, the target lateral velocity, and the target lateral acceleration at the present time based on the target trajectory function y (t) determined in step S14 and the current time t. .. The current time t is the elapsed time after the target orbital function y (t) is determined in step S14, and is equivalent to the elapsed time from the start of the LCA, as can be seen from the processing described later. When the operation support ECU 10 calculates the target trajectory function y (t) in step S14, the operation support ECU resets the timekeeping timer and starts counting up the elapsed time t (= current time t) from the start of the LCA. The target lateral position is calculated by substituting the current time t into the target orbital function y (t), and the target lateral velocity is calculated by substituting the current time t into the function y'(t) obtained by first-derivating the target orbital function y (t). Is calculated by substituting, and the target lateral acceleration is calculated by substituting the current time t into the function y'' (t) obtained by second-order differentiation of the target orbital function y (t). The driving support ECU 10 reads the elapsed time t measured by the timer, and calculates the target lateral state quantity based on the measured time t and the above function.

Hereinafter, the target lateral position at the current time is expressed as y *, the target lateral velocity at the current time is expressed as vy *, and the target lateral acceleration at the current time is expressed as av *. The functional unit of the driving support ECU 10 that calculates the target lateral position y *, the target lateral velocity vy *, and the target lateral acceleration av * in step S15 corresponds to the target lateral state quantity calculating means in the present invention.

Subsequently, in step S16, the driving support ECU 10 calculates a target yaw state amount, which is a target value related to the movement of changing the direction of the own vehicle. The target yaw state quantity represents the target yaw angle θy * of the own vehicle, the target yaw rate γ * of the own vehicle, and the target curvature Cu * at the present time. The target curvature Cu * is the curvature of the target track that changes the lane of the own vehicle, that is, the curvature of the curve component related to the lane change that does not include the curve curvature of the lane.

In step S16, the driving support ECU 10 reads the current vehicle speed v (current vehicle speed detected by the vehicle speed sensor), and at the same time, the vehicle speed v, the target lateral speed v * calculated in step S15, and the target lateral acceleration ay. Based on *, the following equations (12), (13), and (14) are used to calculate the current target yaw angle θy *, target yaw rate γ *, and target curvature Cu *.

θy * = sin ^-1 (vy * / v) ・ ・ ・ (12)
γ * = ay * / v ・ ・ ・ (13)
Cu * = ay * / v ² ... (14)
The target yaw angle θy * is calculated by substituting the value obtained by dividing the target lateral speed vy * by the vehicle speed v into the inverse sine function. The target yaw rate γ * is calculated by dividing the target lateral acceleration ay * by the vehicle speed v. Further, the target curvature Cu * is calculated by dividing the target lateral acceleration ay * by the square value of the vehicle speed v. The functional unit of the driving support ECU 10 that calculates the target yaw angle θy *, the target yaw rate γ *, and the target curvature Cu * corresponds to the target yaw state quantity calculating means of the present invention.

Subsequently, the driving support ECU 10 calculates the target control amount of the LCA in step S17. In the present embodiment, the target steering angle θlca * is calculated as the target control amount. The target steering angle θlca * is calculated by the following equation (15) based on the target lateral position y * calculated in step S15, the target yaw angle θy * calculated in step S16, the target yaw rate γ *, the target curvature Cu *, and the curvature Cu. ) Is calculated.

θlca * = Klca1 ・ (Cu * + Cu) + Klca2 ・ (θy * −θy) + Klca3 ・ (y * −y)
＋ Klca4 ・ (γ * −γ) ＋ Klca5 ・ Σ (y * −y)… (15)

Here, Klca1, Klca2, Klca3, Klca4, and Klca5 are control gains. Cu is the curvature at the present time (at the time of calculation) detected by the camera sensor 12. y corresponds to the horizontal position at the present time (at the time of calculation) detected by the camera sensor 12, that is, Dy. θy is the yaw angle at the present time (at the time of calculation) detected by the camera sensor 12. Further, γ represents the current yaw rate of the own vehicle detected by the yaw rate sensor. The control gain Klca1 may be variably set according to the vehicle speed. As γ, a differential value of the yaw angle θy can also be used.

The first term on the right side is a steering angle component that acts like a feed forward, which is determined according to the added value of the target curvature Cu * and the curvature Cu (curvature of the lane). Klca1 and Cu * are feed forward control amounts for changing lanes, and Klca1 and Cu * are feed forward control amounts for driving the own vehicle along a curve of the lane. The second term on the right side is a steering angle component that acts as a feedback so as to reduce the deviation between the target yaw angle θy * and the actual yaw angle θy. The third term on the right side is a steering angle component that acts as a feedback so as to reduce the deviation between the target lateral position y * and the actual lateral position y. The fourth term on the right side is a steering angle component that acts as a feedback so as to reduce the deviation between the target yaw rate γ * and the actual yaw rate γ. The fifth term on the right side is a steering angle component that works as a feedback so as to reduce the integral value Σ (y * −y) of the deviation between the target lateral position y * and the actual lateral position y. Therefore, the first term on the right side represents the feedforward control amount, and the second to fifth terms on the right side represent the feedback control amount.

The target rudder angle θlca * is not limited to the one calculated by the above five rudder angle components, and may be calculated by using only any of the above five rudder angle components, or other rudder angle components. May be calculated by adding. For example, for the feedback control amount related to the yaw motion, either the deviation of the yaw angle or the deviation of the yaw rate may be used. Further, the feedback control amount using the integrated value Σ (y * −y) of the deviation between the target horizontal position y * and the actual horizontal position y can be omitted.

When the driving support ECU 10 calculates the target control amount in step S17, the driving support ECU 10 transmits a steering command representing the target control amount to the EPS / ECU 20 in the subsequent step S18. In the present embodiment, the driving support ECU 10 calculates the target steering angle θlca * as the target control amount, calculates the target torque at which the target steering angle θlca * is obtained, and issues a steering command representing this target torque by EPS. It may be transmitted to the ECU 20.

When the EPS / ECU 20 receives a steering command from the driving support ECU 10 via the CAN 100, the EPS / ECU 20 drives and controls the steering motor 22 so that the steering angle follows the target steering angle θlca *.

Subsequently, the driving support ECU 10 determines in step S19 whether or not it is the moment when the own vehicle crosses the white line in the lane change direction, that is, the boundary white line WLD (broken line) which is the boundary between the original lane and the target lane. To do.

The camera sensor 12 outputs lane information regarding each lane detected in front of the own vehicle, but the driving support ECU 10 is set to the lane center line CL in the lane in which the own vehicle is located when LCA is being carried out. Such lane information (lane-related vehicle information (Cu, Dy, θy) and lane width, types of left and right white lines, etc.) is used. The lane information related to the lane in which the own vehicle is located is switched by the camera sensor 12 to the information after the change each time the lane in which the own vehicle is located is switched. The camera sensor 12 determines whether or not the center of gravity of the own vehicle has passed the boundary white line WLD based on the image data obtained by imaging, and the center of gravity of the own vehicle has passed the boundary white line WLD. If it is determined that, the lane-related vehicle information (Cu, Dy, θy) is obtained from the information of the lane in which the own vehicle was traveling (in this case, the original lane), and the lane in which the own vehicle entered (in this case, the original lane). , Target lane) information. Therefore, when the lane-related vehicle information is switched, the sign of the lateral deviation Dy is inverted.

For example, if the lateral deviation Dy of the own vehicle located to the right with respect to the lane center line CL is positive and the lateral deviation Dy located to the left is negative, the lateral deviation Dy will be taken as an example. When the own vehicle changes lanes from the left lane to the right lane, the sign of is switched from positive to negative when the own vehicle crosses the boundary white line WLD. In this case, the absolute value of the lateral deviation Dy increases as the own vehicle approaches the boundary white line WLD before the own vehicle crosses the boundary white line WLD, and after the own vehicle crosses the boundary white line WLD, the lane (right side). It decreases as it approaches the lane center line CL of (lane).

The driving support ECU 10 reads the lateral deviation Dy supplied from the camera sensor 12, and determines that the own vehicle has crossed the boundary white line WLD when the sign is inverted (positive → negative or negative → positive).

If it is not determined that the own vehicle has crossed the boundary white line WLD (S19: No), the driving support ECU 10 proceeds to the process in step S20.

In step S20, the driving support ECU 10 determines whether or not the LCA completion condition is satisfied. In the present embodiment, the LCA completion condition is satisfied when the lateral position y of the own vehicle reaches the final target lateral position y *. When the LCA completion condition is not satisfied (S20: No), the operation support ECU 10 returns the process to step S15 and repeats the above-described process. Therefore, the operation support ECU 10 repeatedly executes the processes of steps S15 to S20 at a predetermined calculation cycle. As a result, the target lateral state amount (y *, by *, ay *) according to the elapsed time t is calculated, and the target yaw is calculated according to the calculated target lateral state amount (y *, vy *, ay *). The state quantity (θy *, γ *, Cu *) is calculated, and the target control quantity (θlca *) is calculated based on the calculated target yaw state quantity (θy *, γ *, Cu *).

Then, each time the target control amount (θlca *) is calculated, a steering command representing the target control amount (θlca *) is transmitted to the EPS / ECU 20. In this way, the own vehicle travels along the target track.

When such a process is repeated and the own vehicle approaches the target lane and crosses the boundary white line WLD, the determination in step S19 becomes “Yes”. In this step S19, the driving support ECU 10 determines “Yes” only when the sign of the lateral deviation Dy supplied from the camera sensor 20 is inverted. Therefore, after it is determined that the own vehicle has crossed the boundary white line WLD, the determination in step S19 is "No".

When the driving support ECU 10 determines in step S19 that the own vehicle has crossed the boundary white line WLD (S19: Yes), the driving support ECU 10 proceeds to the process in step S22.

In step S22, the driving support ECU 10 reinitializes the target trajectory calculation parameter. In step S22, the target trajectory calculation parameter is recalculated at the current time t (the time when it is determined that the own vehicle crosses the boundary white line WLD). The target trajectory calculation parameters are the following seven (P11 to P17).
P11. The set horizontal position of the own vehicle with respect to the lane center line of the target lane when it is determined that the own vehicle has crossed the boundary white line (referred to as the set horizontal position when straddling).
P12. The lateral set speed of the own vehicle when it is determined that the own vehicle has crossed the boundary white line (called the set lateral speed when straddling).
P13. The lateral set acceleration of the own vehicle when it is determined that the own vehicle has crossed the boundary white line (called the set lateral acceleration when straddling).
P14. The target lateral position of the own vehicle with respect to the lane center line of the target lane when the LCA is completed (final target lateral position).
P15. Lateral target speed of own vehicle when completing LCA (final target lateral speed).
P16. Lateral target acceleration of the own vehicle when completing LCA (final target lateral acceleration).
P17. Target lane change time, which is the target time for conducting LCA.

The horizontal position (referred to as ycloss) set when straddling the target track calculation parameter P11 is estimated from the target horizontal position calculated immediately before it is determined that the own vehicle has crossed the boundary white line WLD (hereinafter referred to as the previous step). The current target lateral position (target lateral position of the target lane with respect to the lane center line) is used.
The horizontal position ycloss set when straddling is calculated by the following formula.
ycloss = Dy + y (t-1) -Dy_pre
Here, D represents the current lateral deviation (lateral deviation based on the lane center line CL of the target lane = actual lateral position) acquired from the camera sensor 12, and y (t-1) is calculated in the previous step. Represents the target horizontal position. Further, Dy_pre represents the lateral deviation acquired from the camera sensor 12 used in the previous step.

As the straddle set lateral velocity (expressed as bycloss) of the target trajectory calculation parameter P12, the current target lateral velocity estimated from the target lateral motion state amount calculated in the previous step is used. For example, the set lateral speed bycloss when straddling is calculated by the following equation.
bycloss = y'(t-1) + y'' (t-1) × Δt
Here, y'(t-1) represents the target lateral velocity calculated in the previous step, y''(t-1) represents the target lateral acceleration calculated in the previous step, and Δt is the calculation. Represents a period.

As the straddle set lateral acceleration (expressed as aycloss) of the target trajectory calculation parameter P13, the current target lateral acceleration estimated from the target lateral state quantity calculated in the previous step is used. For example, the lateral acceleration aycloss set when straddling is calculated by the following equation.
aycloss = y'' (t-1) + y'''(t-1) × Δt
Here, y'''(t-1) represents the differential value of the target lateral acceleration y'' (t-1) calculated in the previous step, that is, the target lateral jerk (target lateral acceleration).

The horizontal position set when straddling, the lateral speed set when straddling, and the lateral acceleration set when straddling are collectively referred to as the lateral state amount set when straddling.

The final target lateral position of the target track calculation parameter P14 is a position on the lane center line CL of the target lane. As will be described later, the target track function after it is determined that the own vehicle has crossed the boundary white line WLD represents the horizontal position with respect to the lane center line CL of the target lane, so the final target horizontal position is set to zero. Will be done. Further, the final target lateral velocity of the target trajectory calculation parameter P15 and the final target lateral acceleration of the target trajectory calculation parameter P16 are both set to zero.

As the target lane change time of the target track calculation parameter P17, the value set in step S13 is basically used as it is, but the lower limit is set for the remaining time (expressed as rest). The remaining time trest represents the time obtained by subtracting the elapsed time tcloss from the start of LCA to the determination that the own vehicle has crossed the boundary white line WLD from the target lane change time tlen (trest = tlen-tcloss).

When the operation support ECU 10 reinitializes the target trajectory calculation parameter in step S22, the operation support ECU 10 calculates the remaining time trest in parallel, and determines whether or not the remaining time trest is less than the lower limit value tmin. .. Then, the driving support ECU 10 does not correct the target lane change time tlen if the remaining time trest is equal to or greater than the lower limit value tmin. Therefore, the initial target lane change time len calculated in step S13 is set to the target lane change time of the target track calculation parameter P17. On the other hand, when the remaining time trest is less than the lower limit value tmin, the driving support ECU 10 adds the amount (tmin-trest) that the remaining time trest is insufficient with respect to the lower limit value tmin to the initial target lane change time tlen. .. For example, when the lower limit value tmin is set to 3 seconds and the remaining time trest is 2 seconds, 1 second (= 3-2) is added to the target lane change time tlen. Therefore, the target lane change time tlen is increased and corrected so that the remaining time trest is secured at the lower limit value tmin or more.

The operation support ECU 10 reinitializes the target trajectory calculation parameter in step S22, and then recalculates the target trajectory function in step S23. Specifically, the driving support ECU 10 has a target trajectory function y (2) represented by the equation (2) based on the straddle set lateral state amount, the final target lateral state amount, and the target lane change time set in step S22. The coefficients c ₀ , c ₁ , c ₂ , c ₃ , c ₄ , and c ₅ of t) are calculated to determine the target orbital function y (t).

In this case, as shown in FIG. 9, the origin of the lateral position is switched from the lane center line CL of the original lane to the lane center line CL of the target lane. Therefore, since the origin (y = 0) of the target track function y (t) is the lane center line CL of the target lane, the sign of the lateral position is determined. Therefore, the target orbital function y (t) from the start of the LCA has a waveform as shown in FIG.

For example, if the time from the start of LCA to the determination that the own vehicle crosses the boundary white line WLD is tcloss and the corrected target lane change time is tlen, the target track calculation parameter is reinitialized. Conditions, that is, y (tcloss) = ycloss, y'(tcloss) = bycloss, y''(tcloss) = aycloss, y (tlen) = 0, y'(tlen) = 0, y'' (tlen) = From the condition of ₀ , the above coefficients c ₀ , c ₁ , c ₂ , c ₃ , c ₄ , and c ₅ can be calculated. As a result, the target trajectory function y (t) that smoothly changes the own vehicle from the set horizontal state at the time of straddling to the final target horizontal state is set.

When the recalculation of the target trajectory function y (t) is completed, the driving support ECU 10 advances the process to step S15 and repeats the above-described process. In this way, the own vehicle travels along the newly generated target track.

When the driving support ECU 10 determines in step S20 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 S21. That is, the LCA is terminated and the LTA is restarted. As a result, the steering control is performed so that the own vehicle travels along the lane center line CL in the target lane. When the steering support control state is set to the LTA / ON state, the driving support ECU 10 advances the process to step S11 and repeats the same process.

The operation support ECU 10 starts transmitting a blinking command of the blinker 32 in the blinker operation direction to the meter ECU 30 during the period during which the LCA is being performed. Before the start of LCA, the blinker 32 blinks according to the 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), but the blinker 32 blinks due to the blinking command transmitted from the steering ECU 40. Even if the command is stopped, the blinking is continued as it is by the blinking command from the operation support ECU 10. In this case, the blinking end timing of the blinker 32 may be the same as the completion timing of the LCA, or may be earlier than that. For example, the blinking of the blinker may be stopped when the own vehicle reaches the lateral position in front of the final target position by a preset permission distance for turning off (for example, 50 cm).

According to the lane change support device of the present embodiment described above, the target track function is calculated at the start of the LCA, and the own vehicle travels along the target track set by the target track function (in the elapsed time). The steering angle is controlled (so that the corresponding target lateral state can be obtained). Then, when it is determined that the own vehicle crosses the boundary white line WLD, the target trajectory function is calculated again, and the own vehicle travels along the target trajectory set by the recalculated target trajectory function. The steering angle is controlled, and the own vehicle is guided to the final target position. In this way, the lane change of the own vehicle is performed without requiring the driver to operate the steering wheel.

It can be said that the lane recognition accuracy at the start of LCA is better in the lane in which the own vehicle is traveling than in the lane adjacent to the lane in which the own vehicle is traveling. Therefore, in the present embodiment, when the driving support ECU 10 acquires the lane information of the lane in which the own vehicle is traveling from the camera sensor 12 and the lane information is switched, that is, the own vehicle straddles the boundary white line WLD. When it is determined, the target trajectory function corresponding to the lane information after switching is calculated. Therefore, LCA can be carried out using highly accurate lane information.

Further, for example, even if the target lane width is estimated to be equal to the lane width of the original lane and the target track function is calculated, if the lane width of the target lane is different from the lane width of the original lane, LCA If the target trajectory function calculated at the start of is used until the LCA is completed, there is a risk that proper lane change cannot be performed.

On the other hand, in the present embodiment, as described above, since the target track function is recalculated when it is determined that the own vehicle crosses the boundary white line WLD, the lane width of the original lane and the lane of the target lane are recalculated. Even if the width is different, it is possible to make an appropriate lane change.

Further, in the present embodiment, when the LCA is carried out, it is based on the initial lateral position, initial lateral speed, initial lateral acceleration, final target lateral position, final target lateral speed, final target lateral acceleration, and target lane change time. , The target orbital function y (t) is calculated. Then, during the implementation of the LCA, the target lateral position y *, the target lateral velocity vy *, and the target lateral acceleration ay * are sequentially calculated according to the elapsed time t from the start of the LCA. Further, the current vehicle speed v is sequentially acquired, and based on the vehicle speed v, the target lateral speed vy *, and the target lateral acceleration ay *, the target yaw angle θy *, which is a target value for the motion of changing the direction of the own vehicle, The target yaw rate γ * and the target curvature Cu * are sequentially calculated. Then, the steering of the steering wheels is controlled based on the target lateral position y *, the target yaw angle θy *, the target yaw rate γ *, and the target curvature Cu *. Therefore, the own vehicle can be smoothly changed lanes according to the target trajectory function. Further, since the target yaw state amount is set according to the vehicle speed, it is possible to smoothly change lanes reflecting the driver's accelerator operation (change in vehicle speed). In particular, it is possible to smoothly change lanes in cooperation with acceleration / deceleration control by ACC.

In addition, after it is determined that the own vehicle has crossed the boundary white line WLD, it is based on the set lateral state amount at the time of straddling in consideration of the target lateral state amount at the time of the determination and the final target lateral state amount with respect to the target lane. Since the target trajectory function is calculated, the own vehicle can be smoothly driven toward the LCA completion position.

Further, for example, due to a disturbance or the like, the time until it is determined that the own vehicle crosses the boundary white line WLD may be longer than the assumed time. In that case, the time spent on the remaining LCA becomes too short, and there is a risk that LCA cannot be properly performed. Therefore, in the present embodiment, the target lane change time tlen is modified so that the remaining time trest is secured at the lower limit value tmin or more. As a result, an appropriate target trajectory function can be calculated, and the own vehicle can be appropriately changed lanes.

In addition, the target lateral speed (final target lateral speed) and the target lateral acceleration (final target lateral acceleration) of the own vehicle at the completion of the LCA are set to zero, and the target lateral position of the own vehicle at the completion of the LCA (final target lateral acceleration). Since the final target lateral position) is set at the center position of the lane width of the target lane, the own vehicle can be driven along the lane center line CL of the target lane as it is when the LCA is completed. As a result, steering support control can be smoothly transferred from LCA to LTA.

<Modified example of border straddling judgment>
Regarding the boundary straddling determination, in the above embodiment, it is determined whether or not the center of gravity point of the own vehicle crosses the boundary white line WLD, but whether or not a preset specific point of the own vehicle different from the center of gravity point straddles the boundary white line WLD. It may be determined whether or not. Further, the determination that the own vehicle has crossed the boundary may be determined as long as it can be substantially determined that the own vehicle has crossed the boundary. For example, as shown in FIG. 11, if it is an arbitrary set position in the determination allowable area AJ within a predetermined distance in the width direction from the center of the boundary white line WLD, the set position is set to a specific point (including the center of gravity point) of the own vehicle. ) May be detected that the own vehicle has crossed the boundary. The width of this determination allowable area AJ is a size that can substantially determine that the own vehicle straddles the boundary, and is set according to the vehicle width dimension, for example, 1 / n of the vehicle width dimension of the own vehicle. You may decide.

Further, at the start of LCA, the time when the own vehicle is predicted to cross the boundary (for example, the time from the start of LCA to the timing when the own vehicle is predicted to cross the boundary white line WLD) is calculated. , It may be determined that the own vehicle has crossed the boundary when the predicted time has elapsed from the start of the LCA.

Further, in the above embodiment, when the center of gravity of the own vehicle passes the boundary white line WLD, the lane-related vehicle information (Cu, Dy, θy) is switched by the camera sensor 12, so that the driving support ECU 10 can be used. Detects that the own vehicle has crossed the boundary white line WLD. However, it is not always necessary to determine that the own vehicle has crossed the boundary by using the timing at which the lane-related vehicle information is switched. For example, whether the driving support ECU 10 simultaneously acquires information indicating the relative position of the own vehicle with respect to the plurality of white line WLs supplied from the camera sensor 12, and the own vehicle crosses the boundary white line WLD based on the relative position information. It may be determined whether or not.

If the lane in which the own vehicle is traveling (the lane represented by the lane-related vehicle information supplied from the camera sensor 12) differs from the reference lane in which the target track function is set, a period occurs. Only during that period, by offsetting the target track function y (t) by the lane width W, the target track function y (t) is converted to the one whose origin is the lane center line CL of the lane in which the own vehicle is traveling. do it.

<Modification example 1 of recalculation of target orbit function>
For example, it is conceivable that the own vehicle crosses the boundary white line WLD by LCA and then is returned to the original lane side by disturbance. In that case, in the above steering support control routine (FIG. 5), the target trajectory function is recalculated (S22, S23) multiple times. For example, the own vehicle once crosses the boundary white line WLD. If it is determined that the target trajectory function is recalculated, the target trajectory function may not be recalculated (S22, S23) thereafter. For example, as shown in FIG. 12, in the steering support control routine (FIG. 5) of the embodiment, it is preferable to provide the process of step S30 between steps S19 and S22. FIG. 12 shows a modified portion in the steering support control routine of the embodiment.

When the driving support ECU 10 determines in step S19 that it is the moment when the own vehicle crosses the boundary white line WLD (S19: Yes), the operation proceeds to step S30. In step S30, the driving support ECU 10 determines whether or not the target trajectory function recalculation process (S23) has already been performed after the start of the LCA, and the target trajectory function recalculation process has been performed even once. If not (S30: No), the process proceeds to step S22. On the other hand, if the recalculation process of the target orbit function is performed, the process proceeds to step S20.

According to the steering support control routine of the first modification, the recalculation process of the target trajectory function is performed only when it is first determined that the own vehicle crosses the boundary white line WLD, so that stable LCA is performed. be able to. Further, the calculation load of the microcomputer of the driving support ECU 10 can be suppressed to a low level.

<Modification 2 of recalculation of target orbit function>
Further, for example, when the own vehicle returns to the original lane, only when the lateral distance in the return direction is equal to or greater than a predetermined distance, and then when it is determined that the own vehicle has crossed the boundary white line WLD again. , Hysteresis may be provided so as to recalculate the target orbit function. For example, as shown in FIG. 13, in the steering support control routine (FIG. 5) of the embodiment, it is preferable to further provide the processes of steps S31 and S32 between steps S19 and S22. FIG. 13 shows a modified portion in the steering support control routine of the embodiment.

When the driving support ECU 10 determines in step S19 that it is the moment when the own vehicle crosses the boundary white line WLD (S19: Yes), the operation proceeds to step S31. In step S31, the operation support ECU 10 determines whether or not the target trajectory function recalculation process (S23) has already been performed after the start of the LCA, and the target trajectory function recalculation process has been performed even once. If not, the process proceeds to step S22. On the other hand, if the recalculation process of the target orbit function is performed, the process proceeds to step S32.

In step S32, the driving support ECU 10 determines whether or not the return distance of the own vehicle to the original lane is equal to or greater than a preset set value. This set value represents the execution permission determination value of the recalculation processing of the target trajectory function. When the own vehicle returns to the original lane after first determining that the own vehicle has crossed the boundary white line WLD (S19: Yes), the driving support ECU 10 first determines the return distance (return direction from the boundary white line WLD). The maximum value of (distance in the lane width direction) is sequentially stored and updated. The return distance in step S32 represents the maximum value of the current return distance that has been stored and updated.

In step S32, the driving support ECU 10 proceeds to step S20 if the stored return distance is not equal to or greater than the set value at the moment when the own vehicle crosses the boundary white line WLD. Therefore, the recalculation process of the target orbit function is not performed. On the other hand, when the return distance is equal to or greater than the set value, the driving support ECU 10 proceeds to the process in step S22. Therefore, the recalculation process of the target orbit function is performed again.

According to the steering support control routine (FIG. 13) of the second modification, the recalculation process of the target trajectory function is performed again only when the own vehicle is largely returned to the original lane. Therefore, when the behavior of the own vehicle is disturbed by a large disturbance, the own vehicle can be appropriately changed lanes.

In the above two modifications, while the own vehicle is returned to the original lane and is located in the original lane, for example, the lateral position Dy of the original lane supplied from the camera sensor 12 is set to the side of the target lane. It may be converted into a value corresponding to the position (a value with the lane center line CL of the target lane as the origin).

<Modification example of setting the horizontal state amount when straddling>
In the above embodiment, the straddling horizontal position of the target trajectory calculation parameter P11 is set to the current target horizontal position estimated from the target horizontal position calculated in the previous step, but instead, the own vehicle is the boundary. The actual horizontal position, which is the actual detected value when it is determined that the white line WLD is straddled, may be set to the horizontal position set when straddling. Further, for example, the weighted average value of the target horizontal position and the actual horizontal position is obtained by using a predetermined weighting ratio, and the set horizontal position at the time of straddling is set based on both the target horizontal position and the actual horizontal position. You may.

Further, in the above embodiment, the straddling lateral velocity of the target trajectory calculation parameter P12 is set to the current target lateral velocity estimated from the target lateral motion state amount calculated in the previous step, but instead. The actual lateral speed, which is the actual detected value when it is determined that the own vehicle has crossed the boundary white line WLD, may be set as the lateral speed set when straddling. Further, for example, the weighted average value of the target lateral speed and the actual lateral speed is obtained by using a predetermined weighting ratio, and the set lateral acceleration at the time of straddling is set based on both the target lateral speed and the actual lateral speed. You may.

Further, in the above embodiment, the straddling lateral acceleration of the target trajectory calculation parameter P13 is set to the current target lateral acceleration estimated from the target lateral motion state amount calculated in the previous step, but instead. The actual lateral acceleration, which is the actual detected value when it is determined that the own vehicle has crossed the boundary white line WLD, may be set as the lateral acceleration set when straddling. Further, for example, the weighted average value of the target lateral acceleration and the actual lateral acceleration is obtained by using a predetermined weighting ratio, and the set lateral acceleration at the time of straddling is set based on both the target lateral acceleration and the actual lateral acceleration. You may.

Although the lane change support 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 object of the present invention.

For example, in the present embodiment, a quintic function is used as the target orbit function, but it is not always necessary to use the quintic function. Further, in the present embodiment, the target lateral velocity and the target lateral acceleration are calculated as the target lateral motion state amount, but for example, only the target lateral velocity or only the target lateral acceleration may be calculated. Further, in the present embodiment, the target yaw angle, the target yaw rate, and the target curvature are calculated as the target yaw state quantity, but at least one of them may be calculated.

Further, in the present embodiment, it is a premise for carrying out the LCA that the steering support control state is the LTA / ON state (the state in which the LTA is implemented), but such a premise is not necessarily the case. do not need. Also. There may be no premise that ACC is being implemented. Further, in the present embodiment, the LCA is carried out on the condition that the road on which the own vehicle travels is a motorway, but it is not always necessary to provide such a condition.

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 status sensor, 90 ... Driving operation state sensor, CL ... lane center line, WL ... white line, WLD ... boundary white line, Cu ... curvature, Dy ... lateral deviation, θy ... yaw angle, y (t) ... target trajectory function.

Claims (7)

A lane recognition means that recognizes a lane based on an image of a camera that captures the front of the own vehicle and detects the relative positional relationship of the own vehicle with respect to the lane.
A target track calculation means for calculating a target track that causes the own vehicle to change lanes toward the target lane based on the relative positional relationship of the own vehicle with respect to the lane.
In a lane change support device provided with a support control means for controlling lane change support by controlling the steering of the steering wheels so that the own vehicle travels along the target track.
Boundary crossing judgment to determine whether or not the own vehicle straddles the boundary between the original lane, which is the lane in which the own vehicle was traveling at the start of the lane change support, and the target lane adjacent to the original lane in the lane change direction. Equipped with means
The target trajectory calculation means is
At the start of the lane change support, the first calculation means for calculating the target trajectory of the own vehicle from the start to the completion of the lane change support, and
It has a second calculation means for calculating the target trajectory of the own vehicle from that time until the completion of the lane change support when the own vehicle is determined to have crossed the boundary by the boundary crossing determination means.
The support control means
Until it is determined that the own vehicle has crossed the boundary, the steering of the steering wheels is controlled so that the own vehicle travels along the target trajectory calculated by the first calculation means, and the own vehicle crosses the boundary. A lane change support device configured to control the steering of the steering wheels so that the own vehicle travels along the target trajectory calculated by the second calculation means after it is determined that the vehicle has straddled. In the lane change support device according to claim 1,
The first calculation means sets a target lane change time, which is a target time from the start to the completion of the lane change support, and the elapsed time from the start of the lane change support of the own vehicle based on the target lane change time. It is configured to calculate the target trajectory function representing the target lateral position, which is the target position in the lane width direction of the own vehicle according to the time, as the target trajectory.
Based on the target lane change time, the second calculation means sets a target lateral position, which is a target position in the lane width direction of the own vehicle according to the elapsed time after it is determined that the own vehicle has crossed the boundary. A lane change support device configured to calculate the represented target trajectory function as the target trajectory. In the lane change support device according to claim 2.
In the second calculation means, the remaining time, which is the difference between the target lane change time and the time from the start of the lane change support until the own vehicle is determined to have crossed the boundary, is set in advance. A lane change support device configured to increase the target lane change time when the value is less than the lower limit. In the lane change support device according to claim 2 or 3.
The support control means
Based on the target trajectory function calculated by the first calculation means or the second calculation means, the target lateral position of the own vehicle at the present time and the target value of the motion state in the lane width direction of the own vehicle at the present time are the targets. A target lateral state quantity calculating means for sequentially calculating a target lateral state quantity representing a lateral motion state quantity,
The target yaw, which is the target value for the motion of changing the direction of the own vehicle at the present time, is sequentially calculated based on the vehicle speed and the target lateral motion state amount, while sequentially acquiring the vehicle speed of the own vehicle at the present time. State quantity calculation means and
A lane change support device including a steering control means for controlling steering of steering wheels based on the target lateral position and the target yaw state amount. In the lane change support device according to claim 4,
The first calculation means is
When the initial lateral state amount representing the lateral position of the own vehicle with respect to the original lane and the lateral motion state amount which is the motion state in the lane width direction when the lane change support is started, and the lane change support are completed. Based on the final target lateral state amount representing the target lateral position and the target lateral motion state amount of the own vehicle with respect to the original lane and the target lane change time, the self according to the elapsed time from the start of the lane change support. It is configured to calculate a target trajectory function that represents the target lateral position, which is the target position in the lane width direction of the vehicle.
The second calculation means is
When it is determined that the own vehicle crosses the boundary, at least one of the lateral position of the own vehicle and the target lateral position with respect to the target lane, the lateral motion state amount of the own vehicle, and the target lateral motion state amount. Calculates the set lateral state amount at the time of straddling, which represents the set lateral position and the set lateral motion state amount of the own vehicle with respect to the target lane when it is determined that the own vehicle has crossed the boundary based on at least one. And at the same time
The final target lateral state amount representing the target lateral position and the target lateral motion state amount of the own vehicle with respect to the target lane when the straddling set lateral state amount, the lane change support is completed, and the target lane change time. Based on the above, it is configured to calculate a target trajectory function representing a target lateral position which is a target position in the lane width direction of the own vehicle according to the elapsed time after it is determined that the own vehicle has crossed the boundary. Also, a lane change support device. In the lane change support device according to claim 4 or 5.
As the target yaw state amount, the target yaw state amount calculating means has a target yaw angle which is a target value of the horizontal angle of the own vehicle facing the lane and a target yaw rate which is a target value of the yaw rate of the own vehicle. , And a lane change support device configured to calculate at least one of the target curvatures, which is the curvature of the target track. In the lane change support device according to any one of claims 1 to 6.
The lane recognition means outputs lateral position information indicating a position in the lane width direction of the own vehicle with respect to the center line of the lane in which the own vehicle is traveling to the boundary straddling determination means.
When the boundary crossing determination means detects that the lateral position information output by the lane recognition means has switched from the lateral position information related to the original lane to the lateral position information related to the target lane, the own vehicle determines the boundary. A lane change support device configured to determine that you have straddled.

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