Lane departure prevention device

Abstract

To provide a lane deviation prevention device capable of reducing the possibility of letting a driver feel annoyance about an alarm for informing the driver that the vehicle is likely to deviate from a lane.SOLUTION: A lane deviation prevention device 10 executes automatic steering control for performing automatic steering to automatically apply a steering force to an own vehicle 100 to return the own vehicle to a lane in the case that a vehicle deviation condition is satisfied. The lane deviation prevention device also executes alarm control for notifying the driver of the own vehicle that the host vehicle is likely to deviate from the lane when it is determined on the basis of an actual travel state of the own vehicle that an alarm execution condition is satisfied in the case that the automatic steering control is not executed. Meanwhile, the lane deviation prevention device executes alarm control when it is determined on the basis of the travel state of the own vehicle which is realized by the automatic steering control that the alarm execution condition is satisfied in the case that the automatic steering control is executed.SELECTED DRAWING: Figure 8

Description

Technical Field

[0001] The present invention relates to a lane departure prevention device.

Background Art

[0002] As lane departure prevention control for preventing the host vehicle from departing from the lane, there is warning control for giving a warning to the driver of the host vehicle when the host vehicle is about to depart from the lane, or automatic steering control for automatically applying a steering force to the host vehicle to return the host vehicle into the lane. There is known a lane departure prevention device that performs such control.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

[0004] As such a lane departure prevention device, there is known a lane departure prevention device in which a determination value used for determining whether to start warning control and a determination value used for determining whether to start automatic steering control are set individually (see, for example, Patent Document 1).

[0005] The warning control is for prompting the driver to perform a driving operation (departure avoidance operation) for returning the host vehicle that is about to depart from the lane into the lane. On the other hand, the automatic steering control is not for prompting the driver to perform a departure avoidance operation, but for automatically applying a steering force to the host vehicle to return the host vehicle into the lane. Since the purposes of these controls are different, there is a certain advantage in setting individually the determination value used for determining whether to start the warning control and the determination value used for determining whether to start the automatic steering control.

[0006] However, if such determination values are set individually, for example, an alarm may be issued after the automatic steering control is started. In such a case, since the host vehicle is ultimately returned to the lane by the automatic steering control, the driver may feel that an unnecessary alarm has been issued. That is, there is a possibility that the driver may feel annoyed by the alarm.

[0007] An object of the present invention is to provide a lane departure prevention device capable of reducing the possibility of making the driver feel annoyed by an alarm for notifying the driver that the host vehicle may deviate from the lane.

[0008] The lane departure prevention device according to the present invention includes an alarm control for issuing an alarm for notifying the driver of the host vehicle that the host vehicle may deviate from the lane, and an automatic steering control for automatically applying a steering force to the host vehicle that may deviate from the lane to return the host vehicle to the lane, and a control device that executes the above.

[0009] In the lane departure prevention device according to the present invention, the control device is configured to execute the automatic steering control when the automatic steering execution condition is satisfied. Further, when the automatic steering control is not being executed, the control device is configured to execute the alarm control when it is determined that the alarm execution condition is satisfied based on the actual running state of the host vehicle. On the other hand, when the automatic steering control is being executed, the control device is configured to execute the alarm control when it is determined that the alarm execution condition is satisfied based on the running state of the host vehicle realized by the automatic steering control. Furthermore, in the lane departure prevention device according to the present invention, when the control device is not executing the automatic steering control, if it is determined that the warning execution condition is satisfied when the host vehicle reaches a determination line set based on the actual driving state of the host vehicle, and when the automatic steering control is being executed, it is configured to determine that the warning execution condition is satisfied when the host vehicle reaches a determination line set based on the driving state of the host vehicle realized by the automatic steering control. In addition, the control device is configured to determine that the automatic steering execution condition is satisfied when both the automatic steering permission condition and the lane departure condition are satisfied. The automatic steering permission condition is satisfied when the control device can detect a lane dividing object, the current vehicle speed of the host vehicle is within a predetermined vehicle speed range, and the driver has not performed an override operation. Here, the lane dividing object divides the lane in which the host vehicle is traveling, and the override operation is an operation on the steering wheel of the host vehicle to avoid the host vehicle from deviating from the lane. In addition, the lane departure condition is satisfied when it is predicted that the position of the host vehicle will reach a predicted position determination line after a predetermined time. Here, the predicted position determination line is a line extending along the lane dividing object.

[0010] When determining whether the host vehicle deviates from the lane, if the future driving state of the host vehicle can be predicted, it is more accurate to determine whether the host vehicle deviates from the lane based on the future driving state of the host vehicle than to determine whether the host vehicle deviates from the lane based on the actual driving state of the host vehicle (that is, the driving state of the host vehicle at that time). On the other hand, when the automatic steering control is being executed, since the braking force is automatically applied to the host vehicle, it is possible to predict the future driving state of the host vehicle realized by the automatic steering control.

[0011] According to the present invention, when the automatic steering control is being executed, it is determined whether the warning execution condition is satisfied based on the driving state of the host vehicle realized by the automatic steering control. For this reason, it is possible to more accurately determine whether the host vehicle deviates from the lane. Therefore, the warning control is executed only when there is a high possibility that the host vehicle deviates from the lane, and the warning control is not executed when there is a low possibility that the host vehicle deviates from the lane, so that it is possible to reduce the possibility of making the driver feel annoyed by the warning by the warning control.

[0015] Furthermore, According to the present invention, when the automatic steering control is being executed, it is determined that the warning execution condition is satisfied when the host vehicle reaches a determination line set based on the driving state of the host vehicle realized by the automatic steering control. That is, it is determined whether the warning execution condition is satisfied based on the driving state of the host vehicle realized by the automatic steering control. For this reason, when the automatic steering control is being executed, it is possible to more accurately determine whether the host vehicle deviates from the lane. Therefore, the warning control is executed only when there is a high possibility that the host vehicle deviates from the lane, and the warning control is not executed when there is a low possibility that the host vehicle deviates from the lane, so that it is possible to reduce the possibility of making the driver feel annoyed by the warning by the warning control.

[0016] The components of the present invention are not limited to the embodiments of the present invention described below with reference to the drawings. Other objects, other features, and attendant advantages of the present invention will be readily understood from the description of the embodiments of the present invention.

Brief Description of the Drawings

[0017]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Embodiments for Carrying Out the Invention

[0018] Hereinafter, a lane departure prevention device according to an embodiment of the present invention will be described with reference to the drawings. As shown in FIG. 1, a lane departure prevention device 10 according to an embodiment of the present invention is mounted on an own vehicle 100.

[0019] <ecu> The lane departure prevention device 10 includes an ECU 90 as a control device. The ECU is an abbreviation for Electronic Control Unit. The ECU 90 includes a microcomputer as a main part. The microcomputer includes a CPU, a ROM, a RAM, a non-volatile memory, an interface, etc. The CPU is configured to realize various functions by executing instructions, programs, or routines stored in the ROM.

[0020] <Drive device, etc.> In addition, the host vehicle 100 is equipped with a drive device 21, a brake device 22, and a steering device 23.

[0021] <Drive device> The drive device 21 is a device that outputs a driving torque (driving force) applied to the host vehicle 100 to make the host vehicle 100 travel, and is, for example, an internal combustion engine and a motor. The drive device 21 is electrically connected to the ECU 90. The ECU 90 can control the driving torque output from the drive device 21 by controlling the operation of the drive device 21.

[0022] <Brake device> The brake device 22 is a device that outputs a braking torque (braking force) applied to the host vehicle 100 to brake the host vehicle 100, and is, for example, a brake device. The brake device 22 is electrically connected to the ECU 90. The ECU 90 can control the braking torque output from the brake device 22 by controlling the operation of the brake device 22.

[0023] <Steering device> The steering device 23 is a device that outputs a steering torque (steering force) applied to the host vehicle 100 to steer the host vehicle 100, and is, for example, a power steering device. The steering device 23 is electrically connected to the ECU 90. The ECU 90 can control the steering torque output from the steering device 23 by controlling the operation of the steering device 23.

[0024] <Sensors, etc.> Furthermore, the host vehicle 100 is equipped with an accelerator pedal 31, an accelerator pedal operation amount sensor 32, a brake pedal 33, a brake pedal operation amount sensor 34, a steering wheel 35, a steering shaft 36, a steering angle sensor 37, a steering torque sensor 38, a gripping state detection device 40, a vehicle momentum detection device 50, a surrounding information detection device 60, a driver posture acquisition device 70, and an alarm device 80.

[0025] <Accelerator pedal operation amount sensor> The accelerator pedal operation amount sensor 32 is a sensor that detects the operation amount of the accelerator pedal 31. The accelerator pedal operation amount sensor 32 is electrically connected to the ECU 90. The accelerator pedal operation amount sensor 32 transmits information on the detected operation amount of the accelerator pedal 31 to the ECU 90. The ECU 90 acquires the operation amount of the accelerator pedal 31 as the accelerator pedal operation amount AP based on that information.

[0026] The ECU 90 obtains a required driving torque (required driving force) by calculation based on the accelerator pedal operation amount AP and the traveling speed (vehicle speed SPD) of the host vehicle 100. The required driving torque is the driving torque for which an output is required from the driving device 21. The ECU 90 controls the operation of the driving device 21 so that the required driving torque is output.

[0027] <Brake pedal operation amount sensor> The brake pedal operation amount sensor 34 is a sensor that detects the operation amount of the brake pedal 33. The brake pedal operation amount sensor 34 is electrically connected to the ECU 90. The brake pedal operation amount sensor 34 transmits information on the detected operation amount of the brake pedal 33 to the ECU 90. The ECU 90 acquires the operation amount of the brake pedal 33 as the brake pedal operation amount BP based on that information.

[0028] The ECU 90 obtains, by calculation, a required braking torque (required braking force) based on the amount of brake pedal operation BP. The required braking torque is the braking torque for which an output is requested to the braking device 22. The ECU 90 controls the operation of the braking device 22 so that the required braking torque is output.

[0029] <Steering angle sensor> The steering angle sensor 37 is a sensor that detects the rotation angle of the steering shaft 36 with respect to the neutral position. The steering angle sensor 37 is electrically connected to the ECU 90. The steering angle sensor 37 transmits information on the detected rotation angle of the steering shaft 36 to the ECU 90. The ECU 90 obtains the rotation angle of the steering shaft 36 as the steering angle θ based on that information.

[0030] <Steering torque sensor> The steering torque sensor 38 is a sensor that detects the torque input by the driver DR of the host vehicle 100 to the steering shaft 36 via the steering wheel 35. The steering torque sensor 38 is electrically connected to the ECU 90. The steering torque sensor 38 transmits information on the detected torque to the ECU 90. The ECU 90 obtains the torque (driver input torque) input by the driver DR to the steering shaft 36 via the steering wheel 35 based on that information.

[0031] <Grip state detection device> The grip state detection device 40 is a device that detects the grip state of the steering wheel 35 by the driver DR. In this example, it is a touch sensor 41 installed on the steering wheel 35.

[0032] <Touch sensor> The touch sensor 41 is a sensor that detects when the driver DR touches the steering wheel 35. The touch sensor 41 is electrically connected to the ECU 90. When the touch sensor 41 detects that the driver DR has touched the steering wheel 35, it transmits information (a signal) related to the part of the steering wheel 35 that the driver DR touched to the ECU 90. The ECU 90 recognizes the part of the steering wheel 35 that the driver DR is touching based on that information (signal), and can determine whether or not the driver DR is in a state where they can perform a driving operation on the own vehicle 100 based on the recognized part of the steering wheel 35. A state where the driver DR can perform a driving operation on the own vehicle 100 is, for example, a state where the driver DR is gripping with both hands a part of the steering wheel 35 that is appropriate for the driving operation.

[0033] <Vehicle momentum detection device> The vehicle momentum detection device 50 is a device that detects the momentum of the own vehicle 100. In this example, it includes a vehicle speed detection device 51, a longitudinal acceleration sensor 52, a lateral acceleration sensor 53, and a yaw rate sensor 54.

[0034] <Vehicle speed detection device> The vehicle speed detection device 51 is a device that detects the traveling speed (vehicle speed) of the own vehicle 100. For example, it is a wheel speed sensor. The vehicle speed detection device 51 is electrically connected to the ECU 90. The vehicle speed detection device 51 transmits information on the detected vehicle speed of the own vehicle 100 to the ECU 90. The ECU 90 acquires the vehicle speed SPD of the own vehicle 100 based on that information.

[0035] The ECU 90 obtains a required steering torque by calculation based on the acquired steering angle θ, driver input torque, and vehicle speed SPD. The required steering torque is the steering torque for which an output is requested to the steering device 23. The ECU 90 controls the operation of the steering device 23 so that the required steering torque is output from the steering device 23, except when performing automatic steering control described later.

[0036] <Longitudinal acceleration sensor> The longitudinal acceleration sensor 52 is a sensor that detects the acceleration of the host vehicle 100 in the longitudinal direction. The longitudinal acceleration sensor 52 is electrically connected to the ECU 90. The longitudinal acceleration sensor 52 transmits the detected acceleration information to the ECU 90. The ECU 90 acquires the acceleration of the host vehicle 100 in the longitudinal direction as the longitudinal acceleration GX based on the information.

[0037] <Lateral acceleration sensor> The lateral acceleration sensor 53 is a sensor that detects the acceleration of the host vehicle 100 in the lateral direction (width direction). The lateral acceleration sensor 53 is electrically connected to the ECU 90. The lateral acceleration sensor 53 transmits the detected acceleration information to the ECU 90. The ECU 90 acquires the acceleration of the host vehicle 100 in the lateral direction as the lateral acceleration GY based on the information.

[0038] <Yaw rate sensor> The yaw rate sensor 54 is a sensor that detects the yaw rate YR of the host vehicle 100. The yaw rate sensor 54 is electrically connected to the ECU 90. The yaw rate sensor 54 transmits the detected yaw rate YR information to the ECU 90. The ECU 90 acquires the yaw rate YR of the host vehicle 100 based on the information. The yaw rate YR is used, for example, in determining the steering force applied to the host vehicle 100 when automatically applying a steering force to the host vehicle 100 to turn the host vehicle 100 by automatic steering control described later.

[0039] <Surrounding information detection device> The surrounding information detection device 60 is a device that detects information around the host vehicle 100. In this example, it includes an image sensor 61 and a radio wave sensor 62. The image sensor 61 is, for example, a camera. The radio wave sensor 62 is, for example, a radar sensor (such as a millimeter-wave radar). Note that the surrounding information detection device 60 may include a sound wave sensor such as an ultrasonic sensor (clearance sonar) or an optical sensor such as a lidar (LiDAR).

[0040] <Image sensor> The image sensor 61 is electrically connected to the ECU 90. The image sensor 61 captures the surroundings of the host vehicle 100 and transmits information related to the captured image to the ECU 90. The ECU 90 can acquire information (surrounding detection information INF_D) regarding the surroundings of the host vehicle 100 based on that information (image information).

[0041] <Radio wave sensor> The radio wave sensor 62 is electrically connected to the ECU 90. The radio wave sensor 62 transmits radio waves and receives radio waves (reflected waves) reflected by an object. The radio wave sensor 62 transmits information (detection result) related to the transmitted radio waves and the received radio waves (reflected waves) to the ECU 90. In other words, the radio wave sensor 62 detects an object existing in the surroundings of the host vehicle 100 and transmits information (detection result) related to the detected object to the ECU 90. The ECU 90 can acquire information (surrounding detection information INF_D) regarding the object existing in the surroundings of the host vehicle 100 based on that information (radio wave information).

[0042] <Driver posture acquisition device> The driver posture acquisition device 70 is a device that detects the state of consciousness of the driver DR. In this example, it is the driver monitor camera 71. The driver monitor camera 71 is provided inside the host vehicle 100 facing the driver DR so as to be able to capture the face of the driver DR.

[0043] <Driver monitor camera> The driver monitor camera 71 is a camera that captures the face of the driver DR. The driver monitor camera 71 is electrically connected to the ECU 90. The driver monitor camera 71 transmits information (image data) related to the captured image of the face of the driver DR to the ECU 90. The ECU 90 can determine whether or not the driver DR is in a state where he / she can perform a driving operation on the host vehicle 100 based on that information. The state where the driver DR can perform a driving operation on the host vehicle 100 is, for example, a state where the driver DR is facing the steering wheel 35 directly and the eyes of the driver DR are open (i.e., the driver DR is awake).

[0044] <Alarm device> The alarm device 80 is a device for notifying the driver DR that the host vehicle 100 may deviate from the lane LN. In this example, it includes a display device 81, an acoustic device 82, and a vibration device 83.

[0045] <Display device> The display device 81 is a device for displaying an image, and is, for example, a human machine interface (HMI) such as a combination meter or a head-up display (HUD). The display device 81 is electrically connected to the ECU 90. The ECU 90 can cause the display device 81 to display various images.

[0046] <Acoustic device> The acoustic device 82 is a device for outputting sounds such as announcements or electronic sounds such as buzzer sounds, and is, for example, a speaker or a buzzer. The acoustic device 82 is electrically connected to the ECU 90. The ECU 90 can cause the acoustic device 82 to output various sounds or various electronic sounds.

[0047] <Vibration device> The vibration device 83 is a device for applying vibration to the driver DR, and is, for example, a vibrator built into the steering wheel 35 or the driver's seat. The vibration device 83 is electrically connected to the ECU 90. The ECU 90 can apply vibration to the driver DR by operating the vibration device 83.

[0048] <Outline of operation of lane departure prevention device> Next, the outline of the operation of the lane departure prevention device 10 will be described. For example, as shown in FIG. 2, after the host vehicle 100 starts traveling toward the left dividing line 201 (left dividing line 201L), if the driver DR does not perform an appropriate driving operation, the host vehicle 100 will deviate from the lane LN.

[0049] Therefore, when the lane departure prevention device 10 determines that the host vehicle 100 may deviate from the lane LN, the lane departure prevention device 10 executes lane departure prevention control to prevent the host vehicle 100 from deviating from the lane LN. In this example, the lane departure prevention control includes automatic steering control and warning control.

[0050] The automatic steering control is control for automatically applying a steering force to the host vehicle 100 that is about to deviate from the lane LN to return the host vehicle 100 to the lane LN. The warning control is control for giving a warning to the driver DR to notify that the host vehicle 100 may deviate from the lane LN. Hereinafter, these automatic steering control and warning control will be described.

[0051] In this example, the warning by the warning control is at least one of display on the display device 81 of an image indicating that the host vehicle 100 may deviate from the lane LN and / or lighting on the display device 81 of a lamp, output from the acoustic device 82 of a sound indicating that the host vehicle 100 may deviate from the lane LN and / or output from the acoustic device 82 of a buzzer sound, and vibration of the steering wheel 35 and / or the seat of the driver's seat by the vibration device 83.

[0052] <Automatic Steering Control> When the automatic steering execution condition C_LDP is satisfied, the lane departure prevention device 10 executes automatic steering control. In this example, the automatic steering execution condition C_LDP is satisfied when the automatic steering permission condition C_AS is satisfied and the lane departure condition (first departure condition C_D1) is satisfied.

[0053] The automatic steering permission condition C_AS is a condition for determining whether the requirements necessary for executing the automatic steering control in an appropriate manner are satisfied. In this example, the automatic steering permission condition C_AS is satisfied when the lane departure prevention device 10 can detect the lane dividing object 200, the current vehicle speed SPD_N (the current vehicle speed SPD of the host vehicle 100) is within the predetermined vehicle speed range R_TH, and the driver DR is not performing an override operation.

[0054] The lane demarcation object 200 demarcates the lane LN. In this example, it includes the demarcation line 201 on the left side of the lane LN (left demarcation line 201L), the demarcation line 201 on the right side of the lane LN (right demarcation line 201R), the road edge such as grass and soil on the left side of the lane LN (left road edge), the road edge such as grass and soil on the right side of the lane LN (right road edge), the guardrail on the left side of the lane LN (left guardrail), and the guardrail on the right side of the lane LN (right guardrail).

[0055] The lane departure prevention device 10 can detect the left demarcation line 201L, the right demarcation line 201R, the left road edge, the right road edge, the left guardrail, and the right guardrail based on the surrounding detection information INF_D.

[0056] Also, the override operation is, for example, an operation on the steering wheel 35 to avoid the own vehicle 100 deviating from the lane LN (lane departure of the own vehicle 100).

[0057] On the other hand, as shown in FIG. 3, the first departure condition C_D1 is satisfied when the position of the own vehicle 100 (predicted vehicle position POS_P) reaches the first predicted position determination line LIN1_P after a predetermined time T. In this example, the predetermined time T is a time determined in advance as an appropriate time for determining the start timing of the lane departure prevention control.

[0058] The first predicted position determination line LIN1_P is a line extending along the lane demarcation object 200 (in the example shown in FIG. 3, the left demarcation line 201L). The lane departure prevention device 10 sets the first predicted position determination line LIN1_P so that when the predicted vehicle position POS_P reaches the first predicted position determination line LIN1_P and the automatic steering control is started, the lane departure of the own vehicle 100 can be avoided by the automatic steering control while ensuring the running safety of the own vehicle 100.

[0059] When setting the first predicted position determination line LIN1_P, the lane departure prevention device 10 considers the distance (section object distance DIS_200) between the lane section object 200 and the current position of the host vehicle 100 (current vehicle position POS_N), the current vehicle speed SPD (current vehicle speed SPD_N), the steering performance of the steering device 23, the allowable lateral acceleration of the host vehicle 100, and the type of the lane section object 200 (whether the lane section object 200 is a flat object such as a lane line 201 or a road edge, or a three-dimensional structure such as a guardrail), etc., and sets the first predicted position determination line LIN1_P.

[0060] Further, the lane departure prevention device 10 acquires a predicted vehicle position POS_P based on the current vehicle position POS_N (the current position of the host vehicle 100), the current vehicle speed SPD_N (the current vehicle speed SPD), the current lateral acceleration GY_N (the current lateral acceleration GY of the host vehicle 100), and a predetermined time T. Specifically, the lane departure prevention device 10 acquires the predicted vehicle position POS_P by performing an operation according to the following formula (1) based on the current vehicle position POS_N, the current vehicle speed SPD_N, the current lateral acceleration GY_N, and the predetermined time T.

[0061] POS_P = POS_N + SPD_N × T + 1 / 2 × GY_N × T2 …(1)

[0062] In addition, in this example, the lane departure prevention device 10 acquires the current vehicle position POS_N with reference to the position of the lane section object 200 based on the surrounding detection information INF_D.

[0063] When starting the automatic steering control, the lane departure prevention device 10 controls the operation of the steering device 23 so that the host vehicle 100 returns to the lane LN, and applies a steering force to the host vehicle 100. As a result, as shown in FIG. 4, the host vehicle 100 is returned to the lane LN.

[0064] As described above, the lane departure prevention device 10 determines whether or not the first departure condition C_D1 is satisfied based on whether or not the predicted vehicle position POS_P has reached the first predicted position determination line LIN1_P. However, a determination line different from the first predicted position determination line LIN1_P (the first current position determination line LIN1_N) may be set, and whether or not the first departure condition C_D1 is satisfied may be determined based on whether or not the current vehicle position POS_N has reached the first current position determination line LIN1_N.

[0065] In this case, the lane departure prevention device 10 sets the first predicted position determination line LIN1_P as described above, for example. In parallel with this, the distance (predicted lateral movement distance DIS_P) that the host vehicle 100 moves in the lateral direction until a predetermined time T has elapsed from the current time is acquired, and a line obtained by moving the first predicted position determination line LIN1_P by the predicted lateral movement distance DIS_P toward the lane LN side is set as the first current position determination line LIN1_N.

[0066] The lane departure prevention device 10 acquires the predicted lateral movement distance DIS_P by performing an operation according to the following formula 2 based on the current vehicle speed SPD_N, the current lateral acceleration GY_N, and the predetermined time T.

[0067] DIS_P = SPD_N × T + 1 / 2 × GY_N × T2 …(2)

[0068] <Alarm control> Further, when the alarm execution condition C_LDA is satisfied, the lane departure prevention device 10 executes alarm control.

[0069] Here, the alarm execution condition C_LDA is satisfied when the lane departure condition (the second departure condition C_D2) is satisfied. The second departure condition C_D2 is satisfied when the predicted vehicle position POS_P has reached the second predicted position determination line LIN2_P as shown in FIG. 5.

[0070] The second predicted position determination line LIN2_P is a line extending along the lane dividing object 200 (in the example shown in FIG. 5, the left dividing line 201L), and if warning control is started when the predicted vehicle position POS_P reaches this line, the driver DR will notice the warning by this warning control, and the driver DR can sufficiently avoid the lane departure of the host vehicle 100 by operating the steering wheel 35.

[0071] Therefore, if the lane departure prevention device 10 starts warning control when the predicted vehicle position POS_P reaches the second predicted position determination line LIN2_P, it can ensure the driving safety of the host vehicle 100 and avoid the lane departure of the host vehicle 100 by the departure avoidance operation (driving operation for avoiding the host vehicle 100 from departing from the lane LN) by the driver DR. Thus, the second predicted position determination line LIN2_P is set.

[0072] When setting the second predicted position determination line LIN2_P, the lane departure prevention device 10 considers the dividing object distance DIS_200 (the distance between the lane dividing object 200 and the current vehicle position POS_N), the current vehicle speed SPD_N, the driving operation ability of the driver DR (especially, the steering wheel operation ability of the driver DR), and the type of the lane dividing object 200 (whether the lane dividing object 200 is a flat object such as a dividing line or a road edge, or a three-dimensional structure such as a guardrail), etc., and sets the second predicted position determination line LIN2_P.

[0073] Also, when the lane departure prevention device 10 is not executing automatic steering control, it determines whether the warning execution condition C_LDA is satisfied based on the actual driving state of the host vehicle 100. More specifically, the lane departure prevention device 10 acquires the predicted vehicle position POS_P based on the actual driving state of the host vehicle 100. More specifically, as described above, the lane departure prevention device 10 acquires the predicted vehicle position POS_P based on the current vehicle position POS_N, the current vehicle speed SPD_N, the current lateral acceleration GY_N, and a predetermined time T. Specifically, the lane departure prevention device 10 acquires the predicted vehicle position POS_P by performing an operation according to the above formula 1 based on the current vehicle position POS_N, the current vehicle speed SPD_N, the current lateral acceleration GY_N, and the predetermined time T.

[0074] On the one hand, when the lane departure prevention device 10 is executing automatic steering control, it determines whether the alarm execution condition C_LDA is satisfied based on the running state of the host vehicle 100 realized by the automatic steering control. More specifically, the lane departure prevention device 10 acquires a predicted vehicle position POS_P based on the running state of the host vehicle 100 realized by the automatic steering control. More specifically, the lane departure prevention device 10 acquires the predicted vehicle position POS_P based on the current vehicle position POS_N (the current position of the host vehicle 100), the current vehicle speed SPD_N (the current vehicle speed SPD), the predicted lateral acceleration GY_P (the lateral acceleration GY of the host vehicle 100 achieved by the automatic steering control), and a predetermined time T. Specifically, the lane departure prevention device 10 acquires the predicted vehicle position POS_P by performing an operation according to the following formula 3 based on the current vehicle position POS_N, the current vehicle speed SPD_N, the predicted lateral acceleration GY_P, and the predetermined time T.

[0075] POS_P = POS_N + SPD_N × T + 1 / 2 × GY_P × T2 …(3)

[0076] Also, in this example, the deviation avoidance possible condition C_DP is satisfied when the automatic steering permission condition C_AS is satisfied.

[0077] As described above, the lane departure prevention device 10 determines whether the second deviation condition C_D2 is satisfied by whether the predicted vehicle position POS_P reaches the second predicted position determination line LIN2_P. However, a determination line different from the second predicted position determination line LIN2_P (the second current position determination line LIN2_N) may be set, and whether the second deviation condition C_D2 is satisfied may be determined by whether the current vehicle position POS_N reaches the second current position determination line LIN2_N.

[0078] In this case, the lane departure prevention device 10 sets the second predicted position determination line LIN2_P as described above, for example. In parallel with this, it acquires the predicted lateral movement distance DIS_P, and sets, as the second current position determination line LIN2_N, a line obtained by moving the second predicted position determination line LIN2_P by the predicted lateral movement distance DIS_P toward the lane LN side.

[0079] Also, in this case, when the lane departure prevention device 10 is not executing automatic steering control, it acquires the predicted lateral movement distance DIS_P by performing an operation according to Equation 2 above based on the current vehicle speed SPD_N, the current lateral acceleration GY_N, and a predetermined time T.

[0080] On the other hand, when the lane departure prevention device 10 is executing automatic steering control, it acquires the predicted lateral movement distance DIS_P by performing an operation according to Equation 4 below based on the current vehicle speed SPD_N, the predicted lateral acceleration GY_P, and a predetermined time T.

[0081] DIS_P = SPD_N × T + 1 / 2 × GY_P × T2 …(4)

[0082] <Effect> According to the lane departure prevention device 10, the first predicted position determination line LIN1_P and the second predicted position determination line LIN2_P are set in consideration of different elements respectively. Therefore, it is possible for the predicted vehicle position POS_P to reach the first predicted position determination line LIN1_P first, or to reach the second predicted position determination line LIN2_P first. Therefore, when the predicted vehicle position POS_P reaches the second predicted position determination line LIN2_P, the predicted vehicle position POS_P may or may not have reached the first predicted position determination line LIN1_P. That is, when the predicted vehicle position POS_P reaches the second predicted position determination line LIN2_P, automatic steering control may or may not be being executed.

[0083] Generally, when the automatic steering control is being executed, the lateral acceleration GY changes due to the steering force applied to the host vehicle 100 by the automatic steering control. Therefore, when acquiring the position of the host vehicle 100 after a predetermined time T (predicted vehicle position POS_P), it is possible to obtain a more accurate predicted vehicle position POS_P by using the lateral acceleration GY realized by the automatic steering control than by using the lateral acceleration GY at that time (current lateral acceleration GY_N). Accordingly, when the automatic steering control is being executed, using the lateral acceleration GY realized by the automatic steering control to acquire the predicted vehicle position POS_P can reduce the possibility of making the driver DR feel annoyed by the warning due to the warning control compared to acquiring the predicted vehicle position POS_P using the lateral acceleration GY at that time (current lateral acceleration GY_N).

[0084] According to the lane departure prevention device 10, when the automatic steering control is not being executed, the predicted vehicle position POS_P is acquired using the current lateral acceleration GY_N, but when the automatic steering control is being executed, the predicted vehicle position POS_P is acquired using the predicted lateral acceleration GY_P. Accordingly, the possibility of making the driver DR feel annoyed by the warning due to the warning control can be reduced.

[0085] Furthermore, when setting the second predicted position determination line LIN2_P, the lane departure prevention device 10 may be configured to consider whether the driver DR is in a state where the driver DR can perform a driving operation on the host vehicle 100. More specifically, when the driver DR is in a state where the driver DR can perform a driving operation on the host vehicle 100, the lane departure prevention device 10 may be configured to set the second predicted position determination line LIN2_P at a position farther from the lane LN than when the driver DR is not in a state where the driver DR can perform a driving operation on the host vehicle 100. Here, the state where the driver DR can perform a driving operation on the host vehicle 100 means that the driver DR is holding the appropriate part of the steering wheel 35 with both hands for the driving operation, the driver DR is facing the steering wheel 35 directly, and the driver DR's eyes are open (i.e., the driver DR is awake).

[0086] In addition, when setting the second predicted position determination line LIN2_P, the lane departure prevention device 10 may be configured to consider whether the lane marking object 200 is a three-dimensional structure 202. More specifically, when the lane marking object 200 is a three-dimensional structure 202, the lane departure prevention device 10 may be configured to set the second predicted position determination line LIN2_P at a position closer to the lane LN than when the lane marking object 200 is not a three-dimensional structure 202. Here, the three-dimensional structure 202 is, for example, a guardrail as shown in FIG. 6. The lane departure prevention device 10 can detect the three-dimensional structure 202 based on the surrounding detection information INF_D.

[0087] Further, when setting the second predicted position determination line LIN2_P, the lane departure prevention device 10 may be configured to consider whether there is an object 300 that the host vehicle 100 may contact outside the lane demarcation object 200. More specifically, when there is an object 300 that the host vehicle 100 may contact outside the lane demarcation object 200, the lane departure prevention device 10 may be configured to set the second predicted position determination line LIN2_P closer to the lane LN than when there is no object 300 that the host vehicle 100 may contact outside the lane demarcation object 200. Here, as shown in FIG. 2, the object 300 is a pedestrian 301, another vehicle 302, or the like. The lane departure prevention device 10 can detect the object 300 based on the surrounding detection information INF_D. When the lane departure prevention device 10 detects the object 300, for example, when the object 300 exists within a predetermined range in front of the traveling direction of the host vehicle 100, it is determined that there is an object 300 that the host vehicle 100 may contact outside the lane demarcation object 200.

[0088] <Specific operation of lane departure prevention device> Next, the specific operation of the lane departure prevention device 10 will be described. The CPU of the ECU 90 of the lane departure prevention device 10 is configured to execute the routine shown in FIG. 7 at a predetermined calculation cycle. Therefore, at a predetermined timing, the CPU starts processing from step 700 of the routine shown in FIG. 7, advances the processing to step 705, and acquires the predicted vehicle position POS_P. Next, the CPU advances the processing to step 710 and sets the first predicted position determination line LIN1_P. Next, the CPU advances the processing to step 715 and determines whether the first departure condition C_D1 is satisfied.

[0089] If the CPU determines "Yes" in step 715, the processing advances to step 720, and it is determined whether the automatic steering permission condition C_AS is satisfied.

[0090] When the CPU determines "Yes" in step 720, it advances the process to step 725 and executes automatic steering control. Then, the CPU advances the process to step 795 and temporarily ends this routine.

[0091] On the other hand, when the CPU determines "No" in step 715 or step 720, it directly advances the process to step 795 and temporarily ends this routine.

[0092] Furthermore, the CPU is configured to execute the routine shown in FIG. 8 at a predetermined calculation cycle. Therefore, at a predetermined timing, the CPU starts the process from step 800 of the routine shown in FIG. 8, advances the process to step 805, and determines whether automatic steering control is being executed.

[0093] When the CPU determines "Yes" in step 805, it advances the process to step 810 and obtains a predicted vehicle position POS_P by performing an operation according to the above formula 3 (an operation using the predicted lateral acceleration GY_P). Then, the CPU advances the process to step 820.

[0094] On the other hand, when the CPU determines "No" in step 805, it advances the process to step 815 and obtains a predicted vehicle position POS_P by performing an operation according to the above formula 1 (an operation using the current lateral acceleration GY_N). Then, the CPU advances the process to step 820.

[0095] When the CPU advances the process to step 820, it sets a second predicted position determination line LIN2_P. Then, the CPU advances the process to step 825 and determines whether an alarm execution condition C_LDA is satisfied.

[0096] When the CPU determines "Yes" in step 825, it advances the process to step 830 and executes alarm control. Then, the CPU advances the process to step 895 and temporarily ends this routine.

[0097] On the other hand, when the CPU determines "No" in step 825, the process directly proceeds to step 895, and this routine is terminated once. In this case, the alarm control is not executed.

[0098] The above is the specific operation of the lane departure prevention device 10.

[0099] Note that the present invention is not limited to the above-described embodiment, and various modifications can be adopted within the scope of the present invention.

Explanation of Reference Numerals

[0100] 10... Lane departure prevention device, 90... ECU, 23... Steering device, 50 Vehicle momentum detection device, 51... Vehicle speed detection device, 53... Lateral acceleration sensor, 60... Surrounding information detection device, 61... Image sensor, 62... Radio wave sensor, 80... Alarm device, 81... Display device, 82... Acoustic device, 83... Vibration device, 100... Own vehicle, 200... Lane demarcation object, 201... Demarcation line, 202... Three-dimensional structure, 300... Object< / ecu>

Claims

【Claim 1】 A lane departure prevention device comprising a control device that performs warning control for warning a driver of the host vehicle that the host vehicle may deviate from a lane, and automatic steering control for automatically applying a steering force to the host vehicle that may deviate from the lane to return the host vehicle to the lane, wherein the control device executes the automatic steering control when an automatic steering execution condition is satisfied, when the automatic steering control is not being executed, executes the warning control when it is determined that a warning execution condition is satisfied based on the actual driving state of the host vehicle, when the automatic steering control is being executed, executes the warning control when it is determined that the warning execution condition is satisfied based on the driving state of the host vehicle realized by the automatic steering control, is configured as described above, in the lane departure prevention device, the control device when the automatic steering control is not being executed, determines that the warning execution condition is satisfied when the host vehicle reaches a determination line set based on the actual driving state of the host vehicle, when the automatic steering control is being executed, determines that the warning execution condition is satisfied when the host vehicle reaches a determination line set based on the driving state of the host vehicle realized by the automatic steering control, is configured as described above, the control device is configured to determine that the automatic steering execution condition is satisfied when both an automatic steering permission condition and a lane departure condition are satisfied, the automatic steering permission condition is satisfied when the control device can detect a lane dividing object, the current vehicle speed of the host vehicle is within a predetermined vehicle speed range, and the driver is not performing an override operation, the lane dividing object divides the lane in which the host vehicle is traveling, the override operation is an operation on the steering wheel of the host vehicle to avoid the host vehicle deviating from the lane, the lane departure condition is satisfied when it is predicted that the position of the host vehicle will reach a predicted position determination line after a predetermined time, the predicted position determination line is a line extending along the lane dividing object, Lane departure prevention device.

Images