Lane departure prevention device

Abstract

The lane departure prevention device performs automatic steering control when the lane departure condition is satisfied when the automatic steering permission condition is satisfied; if the automatic steering control is not performed when the alarm execution condition is satisfied, the device performs alarm control in such a manner that the alarm level becomes a predetermined alarm level when the departure avoidable condition that the automatic steering permission condition is satisfied is not satisfied; and if the automatic steering control is not performed when the alarm execution condition is satisfied, the device does not perform alarm control or performs alarm control in such a manner that the alarm level becomes a level lower than the predetermined alarm level when the departure avoidable condition is satisfied.

Description

Technical Field

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

[0002] A lane departure prevention device is known that performs alarm control or automatic steering control as a lane departure prevention control for preventing a vehicle from deviating from a lane. The alarm control is used to alert the driver of the vehicle of the situation when the vehicle is about to deviate from the lane, and the automatic steering control is used to automatically apply steering force to the vehicle to return the vehicle to the lane. Summary of the invention

[0003] As such a lane departure prevention device, there is known a lane departure prevention device configured to separately set a determination value for determining whether to start warning control and a determination value for determining whether to start automatic steering control (for example, see Japanese Patent Application Laid-Open No. 2005-242483).

[0004] The alarm control is a control used to prompt the driver to perform a driving operation for returning the vehicle that is about to deviate from the lane to the lane (avoiding deviation operation). On the other hand, the automatic steering control is not a control used to prompt the driver to perform an avoiding deviation operation, but a control used to automatically apply steering force to the vehicle to return the vehicle to the lane. The purposes of these controls are different, and therefore there is a certain advantage in separately setting the judgment value for determining whether to start the alarm control and the judgment value for determining whether to start the automatic steering control.

[0005] However, if the determination values ​​are set separately, for example, there is a case where the alarm is issued and the driver who notices the alarm wants to voluntarily perform the deviation avoidance operation and starts the automatic steering control. In such a case, as a result, the host vehicle returns to the lane by the automatic steering control, and the driver may feel that the alarm is issued unnecessarily. In other words, the driver may feel annoyed by the alarm.

[0006] An object of the present invention is to provide a lane departure prevention device that can reduce the annoyance that a driver feels with respect to an alarm for notifying the driver that a host vehicle may depart from a lane.

[0007] The lane departure prevention device of the present invention includes a control device, which performs: alarm control, which performs an alarm for notifying the driver of the vehicle that the vehicle may deviate from the lane; and automatic steering control, which performs automatic steering by automatically applying steering force to the vehicle that may deviate from the lane to return the vehicle to (be located in) the lane.

[0008] In the lane departure prevention device of the present invention, the control device is configured to execute the automatic steering control when the lane departure condition is satisfied when the automatic steering permission condition is satisfied. In addition, the control device is configured to execute the alarm control in a manner that makes the level of the alarm become a predetermined alarm level when the avoidable deviation condition that is satisfied when the automatic steering permission condition is satisfied is not satisfied when the automatic steering control is not executed when the alarm execution condition is satisfied. On the other hand, the control device is configured to not execute the alarm control when the avoidable deviation condition is satisfied when the automatic steering control is not executed when the alarm execution condition is satisfied, or to execute the alarm control in a manner that makes the level of the alarm become a level lower than the predetermined alarm level.

[0009] In the case where the automatic steering permission condition is satisfied but the automatic steering control is not executed, if the lane departure condition is satisfied later, the automatic steering control is started, and the vehicle is prevented from deviating from the lane by the automatic steering control. That is, when the automatic steering permission condition is satisfied but the automatic steering control is not executed, there is a high possibility that the vehicle is prevented from deviating from the lane (lane departure of the vehicle) by the automatic steering control to be started later. In this case, although the alarm execution condition is satisfied and the alarm control is started, the result is that although the vehicle is prevented from deviating from the lane by the automatic steering control, the alarm is issued, and the driver may feel annoyed by the alarm.

[0010] According to the present invention, the departure avoidable condition is set to be satisfied when the automatic steering permission condition is satisfied. Therefore, although the automatic steering control is not executed at the time when the alarm execution condition is satisfied, when it is possible to start the automatic steering control later and avoid the lane departure of the host vehicle by the automatic steering control, the alarm control is not executed or the alarm control with the alarm level lowered is executed. Therefore, the possibility of the driver feeling annoyed by the alarm can be reduced.

[0011] In the lane departure prevention device of the present invention, the lane departure avoidable condition may include a condition that the driver of the host vehicle is in a state where he can perform a driving operation on the host vehicle.

[0012] If the driver is in a state where he or she is able to perform driving operations on the vehicle, then even if no alarm is issued when the vehicle is about to deviate from the lane, it can be expected that the driver will spontaneously perform a deviation avoidance operation (a driving operation used to prevent the vehicle from deviating from the lane). However, if no alarm is issued when the driver is not in a state where he or she is able to perform driving operations on the vehicle, it cannot be expected that the driver will spontaneously perform a deviation avoidance operation. Therefore, in such a case, it is preferable to issue an alarm in order to further increase the possibility of avoiding the vehicle's lane deviation.

[0013] According to the present invention, since the departure avoidable condition includes the condition that the driver is in a state where the driving operation can be performed, the response of not performing the warning control even if the warning execution condition is satisfied, or performing the warning control by lowering the level of the warning when the warning execution condition is satisfied is only adopted when the driver is in a state where the driving operation can be performed when the host vehicle is about to depart from the lane. Therefore, even if the warning control is not performed or the warning control is performed by lowering the level of the warning, it is possible to fully expect that the driver will spontaneously perform the departure avoidance operation, and thus the possibility of avoiding the lane departure of the host vehicle can be ensured.

[0014] Furthermore, in the lane departure prevention device of the present invention, the departure avoidable condition may include a condition that a partitioning object partitioning the lane is not a three-dimensional structure.

[0015] When the vehicle deviates from the lane in a situation where the demarcation object that demarcates the lane is a three-dimensional structure, the vehicle may come into contact with the three-dimensional structure. Therefore, in such a situation, even if the vehicle can avoid lane deviation through automatic steering control and thus avoid contact with the three-dimensional structure, in order to ensure the driving safety of the vehicle, it is preferred to issue an alarm to prompt the driver to perform a deviation avoidance operation. In other words, even if the response of not executing the alarm control even if the alarm execution condition is met or the response of executing the alarm control by lowering the alarm level when the alarm execution condition is met is adopted, such a response is preferably limited to the situation where there is no possibility of contact between the vehicle and the three-dimensional structure.

[0016] According to the present invention, since the deviation avoidable condition includes the condition that the demarcation object (lane demarcation object) demarcating the lane is not a three-dimensional structure, the response of not executing the alarm control even if the alarm execution condition is satisfied, or executing the alarm control by lowering the alarm level when the alarm execution condition is satisfied, is only adopted when the lane demarcation object is not a three-dimensional structure when the vehicle is about to deviate from the lane. Therefore, even if the alarm control is not executed or the alarm control is executed by lowering the alarm level, the driving safety of the vehicle can be ensured.

[0017] Furthermore, in the lane departure prevention device of the present invention, the departure avoidable condition may include a condition that there is no object with which the host vehicle may come into contact outside a partition that partitions the lane.

[0018] When the object that the vehicle may collide with is outside the lane demarcation object when the vehicle deviates from the lane, in order to ensure the driving safety of the vehicle, it is preferred to issue an alarm to prompt the driver to perform a deviation avoidance operation. In other words, even if the response of not executing the alarm control even if the alarm execution condition is met or the response of executing the alarm control by lowering the alarm level when the alarm execution condition is met is adopted, such a response is preferably limited to the case where the object that the vehicle may collide with is not outside the lane demarcation object.

[0019] According to the present invention, since the deviation avoidable condition includes the condition that there is no object that the vehicle may contact outside the lane demarcation object, the response of not executing the alarm control even if the alarm execution condition is satisfied, or executing the alarm control by lowering the alarm level when the alarm execution condition is satisfied, is only adopted when there is no object that the vehicle may collide with when the vehicle is about to deviate from the lane outside the lane demarcation object. Therefore, even if the alarm control is not executed or the alarm control is executed by lowering the alarm level, the driving safety of the vehicle can be ensured.

[0020] In addition, in the lane departure prevention device of the present invention, the control device may also be configured to, when the avoidable deviation condition is met and the alarm control is executed when the alarm execution condition is met, delay the timing of starting the alarm control compared to when the avoidable deviation condition is not met when the alarm execution condition is met.

[0021] If the start of alarm control is delayed, the level of the alarm issued by the alarm control can be said to be lowered. In other words, if the start of alarm control is delayed, the execution period of alarm control is shortened accordingly, so the level of the alarm issued by the alarm control can be said to be lowered.

[0022] According to the present invention, when the deviation avoidable condition is satisfied when the alarm execution condition is satisfied, the timing of starting the alarm control is delayed compared to when the deviation avoidable condition is not satisfied when the alarm execution condition is satisfied. Therefore, when the possibility that the vehicle will be returned to the lane by the automatic steering control is high, the alarm control that reduces the level of the alarm is executed. Therefore, the possibility that the driver will feel annoyed by the alarm issued by the alarm control can be reduced.

[0023] 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 additional advantages of the present invention will be easily understood from the description of the embodiments of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Features, advantages, and technical and industrial significance of exemplary embodiments of the present invention will be described below with reference to the accompanying drawings, in which like reference numerals represent like elements, and in which:

[0025] Figure 1 It is a diagram showing a lane departure prevention device and a vehicle (host vehicle) equipped with the lane departure prevention device according to an embodiment of the present invention.

[0026] Figure 2 The diagram shows a scene in which the host vehicle is traveling in a direction deviating from the lane.

[0027] Figure 3 This is a diagram showing a scenario in which the predicted vehicle position reaches the first predicted position determination line.

[0028] Figure 4 The figure shows a scene in which a steering force is applied to the host vehicle by the automatic steering control to return the host vehicle to the lane.

[0029] Figure 5 This is a diagram showing a scenario in which the predicted vehicle position reaches the second predicted position determination line.

[0030] Figure 6 The figure shows a road with a guardrail installed on the left side of the lane.

[0031] Figure 7 This is a flowchart showing a routine executed by the lane departure prevention device according to the embodiment of the present invention.

[0032] Figure 8 This is a flowchart showing a routine executed by the lane departure prevention device according to the embodiment of the present invention.

[0033] Fig. 9 This is a flowchart showing a routine executed by the lane departure prevention device according to the embodiment of the present invention. DETAILED DESCRIPTION

[0034] Hereinafter, a lane departure prevention device according to an embodiment of the present invention will be described with reference to the accompanying drawings. Figure 1 As shown, a lane departure prevention device 10 according to an embodiment of the present invention is mounted on a host vehicle 100 .

[0035] <ecu>

[0036] The lane departure prevention device 10 includes an ECU 90 as a control device. ECU is an abbreviation for an 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, and an interface (INTERFACE). The CPU implements various functions by executing instructions, programs, or routines stored in the ROM.

[0037] <Drive device, etc.>

[0038] Furthermore, the vehicle 100 is equipped with a driving device 21 , a braking device 22 , and a steering device 23 .

[0039] <Drive device>

[0040] The drive device 21 is a device that outputs a driving torque (driving force) given to the vehicle 100 in order to make the vehicle 100 travel, such as 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.

[0041] <Braking device>

[0042] The brake device 22 is a device that outputs a braking torque (braking force) applied to the host vehicle 100 for braking the host vehicle 100. 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.

[0043] <Steering gear>

[0044] The steering device 23 is a device that outputs a steering torque (steering force) given to the vehicle 100 for steering the 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.

[0045] <Sensors, etc.>

[0046] In addition, the 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 holding state detection device 40, a vehicle movement amount detection device 50, a peripheral information detection device 60, a driver posture acquisition device 70 and an alarm device 80.

[0047] <Accelerator pedal operation amount sensor>

[0048] 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 sends information on the detected operation amount of the accelerator pedal 31 to the ECU 90. Based on the information, the ECU 90 acquires the operation amount of the accelerator pedal 31 as the accelerator pedal operation amount AP.

[0049] The ECU 90 obtains the required driving torque (required driving force) by calculation based on the accelerator pedal operation amount AP and the running speed (vehicle speed SPD) of the vehicle 100. The required driving torque is the driving torque required to be output by the drive device 21. The ECU 90 controls the operation of the drive device 21 so that the drive device 21 outputs the required driving torque.

[0050] <Brake pedal operation amount sensor>

[0051] 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 sends information on the detected operation amount of the brake pedal 33 to the ECU 90. Based on the information, the ECU 90 obtains the operation amount of the brake pedal 33 as the brake pedal operation amount BP.

[0052] The ECU 90 obtains the required braking torque (required braking force) by calculation based on the brake pedal operation amount BP. The required braking torque is the braking torque required to be output by the braking device 22. The ECU 90 controls the operation of the braking device 22 so that the braking device 22 outputs the required braking torque.

[0053] <Steering angle sensor>

[0054] The steering angle sensor 37 is a sensor that detects the rotation angle of the steering shaft 36 relative 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 acquires the rotation angle of the steering shaft 36 as the steering angle θ based on the information.

[0055] <Steering torque sensor>

[0056] The steering torque sensor 38 is a sensor that detects the torque input to the steering shaft 36 by the driver DR of the vehicle 100 via the steering wheel 35. The steering torque sensor 38 is electrically connected to the ECU 90. The steering torque sensor 38 sends information on the detected torque to the ECU 90. The ECU 90 acquires the torque (driver input torque) input to the steering shaft 36 by the driver DR via the steering wheel 35 based on the information.

[0057] <Holding state detection device>

[0058] The grip state detection device 40 is a device that detects the grip state of the steering wheel 35 by the driver DR, and is a touch sensor 41 provided on the steering wheel 35 in this example.

[0059] <Touch Sensor>

[0060] The touch sensor 41 is a sensor that detects the contact between the driver DR and the steering wheel 35. The touch sensor 41 is electrically connected to the ECU 90. When the touch sensor 41 detects the contact between the driver DR and the steering wheel 35, it sends information (signal) related to the part of the steering wheel 35 that the driver DR is in contact with to the ECU 90. The ECU 90 can identify the part of the steering wheel 35 that the driver DR is in contact with based on the information (signal), and determine whether the driver DR is in a state where he can perform driving operations on the vehicle 100 based on the identified part of the steering wheel 35. The state in which the driver DR can perform driving operations on the vehicle 100 is, for example, a state in which the driver DR holds the part of the steering wheel 35 that is appropriate for the driving operation with both hands.

[0061] <Vehicle Movement Detection Device>

[0062] The vehicle motion amount detection device 50 is a device for detecting the motion amount of the host vehicle 100 , and in this example, includes a vehicle speed detection device 51 , a longitudinal acceleration sensor 52 , a lateral acceleration sensor 53 , and a yaw rate sensor 54 .

[0063] <Vehicle speed detection device>

[0064] The vehicle speed detection device 51 is a device for detecting the running speed (vehicle speed) of the host vehicle 100, and is, for example, a wheel speed sensor. The vehicle speed detection device 51 is electrically connected to the ECU 90. The vehicle speed detection device 51 sends information on the detected vehicle speed of the host vehicle 100 to the ECU 90. The ECU 90 acquires the vehicle speed SPD of the host vehicle 100 based on the information.

[0065] The ECU 90 obtains the required steering torque by calculation based on the obtained steering angle θ, the driver input torque and the vehicle speed SPD. The required steering torque is the steering torque required to be output 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 the automatic steering control described later.

[0066] <Longitudinal acceleration sensor>

[0067] The longitudinal acceleration sensor 52 is a sensor for detecting the acceleration in the front-rear direction of the host vehicle 100. The longitudinal acceleration sensor 52 is electrically connected to the ECU 90. The longitudinal acceleration sensor 52 transmits information of the detected acceleration to the ECU 90. The ECU 90 obtains the acceleration in the front-rear direction of the host vehicle 100 as the longitudinal acceleration GX based on the information.

[0068] <Lateral acceleration sensor>

[0069] The lateral acceleration sensor 53 is a sensor that detects the lateral acceleration (width direction) of the host vehicle 100. The lateral acceleration sensor 53 is electrically connected to the ECU 90. The lateral acceleration sensor 53 sends information on the detected acceleration to the ECU 90. The ECU 90 acquires the lateral acceleration of the host vehicle 100 as the lateral acceleration GY based on the information.

[0070] <Yaw rate sensor>

[0071] The yaw rate sensor 54 is a sensor for detecting 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 information of the detected yaw rate YR 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, to determine the steering force applied to the host vehicle 100 when the host vehicle 100 is automatically applied with the automatic steering control described later to turn the host vehicle 100.

[0072] <Surrounding Information Detection Device>

[0073] The surrounding information detection device 60 is a device for detecting information about the surroundings of the vehicle 100, and in this example, includes an image sensor 61 and an electric wave sensor 62. The image sensor 61 is, for example, a camera. The electric wave sensor 62 is, for example, a radar sensor (millimeter wave radar, etc.). In addition, the surrounding information detection device 60 may also include an acoustic sensor such as an ultrasonic sensor (clearance sonar), or an optical sensor such as a laser radar (LiDAR).

[0074] <Image Sensor>

[0075] 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 obtain information related to the surroundings of the host vehicle 100 (surrounding detection information INF_D) based on the information (image information).

[0076] <Radio wave sensor>

[0077] 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 results) 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 objects existing in the vicinity of the host vehicle 100 and transmits information (detection results) related to the detected objects to the ECU 90. The ECU 90 can obtain information (peripheral detection information INF_D) related to objects existing in the vicinity of the host vehicle 100 based on the information (radio wave information).

[0078] <Driver posture acquisition device>

[0079] The driver posture acquisition device 70 is a device for detecting the consciousness state of the driver DR, and in this example, is a driver monitoring camera 71. The driver monitoring camera 71 is installed in the interior of the host vehicle 100 facing the driver DR so as to be able to capture the face of the driver DR.

[0080] <Driver Monitoring Camera>

[0081] The driver monitoring camera 71 is a camera that captures the face of the driver DR. The driver monitoring camera 71 is electrically connected to the ECU 90. The driver monitoring camera 71 sends information (image data) related to the captured image of the driver DR's face to the ECU 90. The ECU 90 can determine based on the information whether the driver DR is in a state where he can perform driving operations on the vehicle 100. The state where the driver DR can perform driving operations on the vehicle 100 is, for example, a state where the driver DR is facing the steering wheel 35 and the driver DR's eyes are open (i.e., the driver DR is awake).

[0082] <Alarm device>

[0083] The warning device 80 is a device for notifying the driver DR that the host vehicle 100 may deviate from the lane LN, and in this example, includes a display device 81 , an audio device 82 , and a vibration device 83 .

[0084] <Display device>

[0085] The display device 81 is a device that displays images, and is, for example, a human-machine interface (HMI) such as a combination meter and 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.

[0086] <Sound Device>

[0087] The audio device 82 is a device that outputs sounds such as announcements or electronic sounds such as buzzer sounds, and is, for example, a speaker or a buzzer. The audio device 82 is electrically connected to the ECU 90. The ECU 90 can output various sounds or various electronic sounds from the audio device 82.

[0088] <Vibration device>

[0089] 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.

[0090] <Overview of Lane Departure Prevention Device Operation>

[0091] Next, the operation overview of the lane departure prevention device 10 is described. Figure 2 As shown, 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.

[0092] Therefore, when determining that the host vehicle 100 may deviate from the lane LN, the lane departure prevention device 10 executes lane departure prevention control for preventing 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.

[0093] The automatic steering control is a 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 a control for issuing a warning to notify the driver DR that the host vehicle 100 may deviate from the lane LN. The automatic steering control and the warning control are described below.

[0094] In addition, in this example, the alarm performed by the alarm control is performed by at least one of the display of an image on the display device 81 indicating that the vehicle 100 may deviate from the lane LN and / or the lighting of a light on the display device 81, the output of a sound from the audio device 82 indicating that the vehicle 100 may deviate from the lane LN and / or the output of a buzzer sound from the audio device 82, and the vibration of the steering wheel 35 and / or the driver's seat by the vibration device 83.

[0095] <Automatic steering control>

[0096] The lane departure prevention device 10 executes the automatic steering control when the automatic steering execution condition C_LDP is satisfied. 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.

[0097] The automatic steering permission condition C_AS is a condition used to determine whether the necessary conditions for executing the automatic steering control in an appropriate form are met. In this example, it is established when the lane departure prevention device 10 is able to detect the lane dividing object 200 and the current vehicle speed SPD_N (the current vehicle speed SPD of the vehicle 100) is within the predetermined vehicle speed range R_TH and the driver DR does not perform an override operation (English: override operation).

[0098] Lane dividing object 200 divides lane LN, and in this example, is a dividing line 201 on the left side of lane LN (left dividing line 201L), a dividing line 201 on the right side of lane LN (right dividing line 201R), grass, dirt, etc. on the left side of lane LN (left side road end), grass, dirt, etc. on the right side of lane LN (right side road end), a guardrail on the left side of lane LN (left side guardrail), and a guardrail on the right side of lane LN (right side guardrail).

[0099] The lane departure prevention device 10 can detect the left dividing line 201L, the right dividing 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.

[0100] In addition, the override operation is, for example, an operation on the steering wheel 35 for preventing the host vehicle 100 from deviating from the lane LN (lane deviation of the host vehicle 100 ).

[0101] On the other hand, Figure 3 As shown, the first departure condition C_D1 is satisfied when the position of the host 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 predetermined as an appropriate time for determining the start timing of the lane departure prevention control.

[0102] The first estimated position determination line LIN1_P is along the lane dividing object 200 (at Figure 3 In the example shown, it is a line extending from the left side demarcation line 201L. The lane departure prevention device 10 sets the first predicted position determination line LIN1_P in the following manner: if the automatic steering control is started when the predicted vehicle position POS_P reaches the first predicted position determination line LIN1_P, the driving safety of the host vehicle 100 can be ensured and the lane departure of the host vehicle 100 can be avoided by the automatic steering control.

[0103] When setting the first predicted position determination line LIN1_P, the lane departure prevention device 10 considers the distance (lane dividing object distance DIS_200) between the lane dividing object 200 and the current position (current vehicle position POS_N) of the host vehicle 100, 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 lane dividing object 200 (whether the lane dividing object 200 is a dividing line 201, a flat object such as a road end, or a three-dimensional structure such as a guardrail), etc.

[0104] In addition, the lane departure prevention device 10 obtains 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 current lateral acceleration GY_N (the current lateral acceleration GY of the host vehicle 100), and the predetermined time T. Specifically, the lane departure prevention device 10 obtains the predicted vehicle position POS_P by calculating 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.

[0105] POS_P=POS_N+SPD_N×T+1 / 2×GY_N×T 2 … (1)

[0106] Furthermore, in this example, the lane departure prevention device 10 obtains the current vehicle position POS_N based on the surrounding detection information INF_D with reference to the position of the lane defining object 200 .

[0107] When the lane departure prevention device 10 starts the automatic steering control, it controls the operation of the steering device 23 to apply a steering force to the host vehicle 100 so that the host vehicle 100 returns to the lane LN. Figure 4 As shown, the host vehicle 100 returns to the lane LN.

[0108] In addition, as described above, the lane departure prevention device 10 determines whether the first departure condition C_D1 is satisfied based on whether the predicted vehicle position POS_P reaches the first predicted position determination line LIN1_P, but may also be configured to set a determination line (first current position determination line LIN1_N) different from the first predicted position determination line LIN1_P, and determine whether the first departure condition C_D1 is satisfied based on whether the current vehicle position POS_N reaches the first current position determination line LIN1_N.

[0109] In this case, the lane departure prevention device 10 sets the first predicted position determination line LIN1_P as described above, and in parallel, obtains the distance that the vehicle 100 has moved laterally during the period from the current time point to the predetermined time T (predicted lateral movement distance DIS_P), and sets the line obtained by moving the first predicted position determination line LIN1_P to the lane LN side by the predicted lateral movement distance DIS_P as the first current position determination line LIN1_N.

[0110] Furthermore, the lane departure prevention device 10 obtains the predicted lateral movement distance DIS_P by calculation according to the following equation 2 based on the current vehicle speed SPD_N, the current lateral acceleration GY_N, and the predetermined time T.

[0111] DIS_P=SPD_N×T+1 / 2×GY_N×T 2 … (2)

[0112] <Alarm Control>

[0113] Furthermore, when the lane departure prevention device 10 does not execute the automatic steering control when the warning execution condition C_LDA is satisfied, it executes the warning control when the departure avoidable condition C_DP is not satisfied.

[0114] On the other hand, if the lane departure prevention device 10 does not execute the automatic steering control when the warning execution condition C_LDA is satisfied, it does not execute the warning control when the departure avoidable condition C_DP is satisfied.

[0115] Furthermore, when the lane departure prevention device 10 is executing the automatic steering control when the warning execution condition C_LDA is satisfied, the lane departure prevention device 10 does not execute the warning control.

[0116] Here, the warning execution condition C_LDA is satisfied when the lane departure condition (the second departure condition C_D2) is satisfied. Figure 5 As shown, the second deviation condition C_D2 is satisfied when the predicted vehicle position POS_P reaches the second predicted position determination line LIN2_P.

[0117] The second estimated position determination line LIN2_P is along the lane dividing object 200 (at Figure 5 In the example shown, the line is an extension of the left-side dividing line 201L), and is a line as follows: if the alarm control is started when the predicted vehicle position POS_P reaches this line, the driver DR notices the alarm issued by the alarm control, and the driver DR operates the steering wheel 35, thereby being able to fully avoid lane deviation of the vehicle 100.

[0118] Therefore, the lane departure prevention device 10 sets the second predicted position determination line LIN2_P in the following manner: if the alarm control is started when the predicted vehicle position POS_P reaches the second predicted position determination line LIN2_P, the driving safety of the vehicle 100 can be ensured and the lane departure of the vehicle 100 can be avoided through the driver DR's deviation avoidance operation (driving operation for avoiding the vehicle 100 from the lane LN).

[0119] When setting the second predicted position determination line LIN2_P, the lane departure prevention device 10 takes into account the lane 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 lane dividing object 200 (whether the lane dividing object 200 is a dividing line 201, a flat object such as a road end, or a three-dimensional structure such as a guardrail), etc.

[0120] As described above, the lane departure prevention device 10 obtains 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 the predetermined time T. Specifically, the lane departure prevention device 10 obtains the predicted vehicle position POS_P by performing calculations 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.

[0121] Furthermore, in this example, it is possible to avoid the departure condition C_DP from being satisfied when the automatic steering permission condition C_AS is satisfied.

[0122] In addition, as described above, the lane departure prevention device 10 determines whether the second departure condition C_D2 is satisfied based on whether the predicted vehicle position POS_P reaches the second predicted position determination line LIN2_P, but may also be configured to set a determination line (second current position determination line LIN2_N) different from the second predicted position determination line LIN2_P, and determine whether the second departure condition C_D2 is satisfied based on whether the current vehicle position POS_N reaches the second current position determination line LIN2_N.

[0123] In this case, the lane departure prevention device 10 sets the second predicted position determination line LIN2_P as described above, and in parallel, obtains the predicted lateral movement distance DIS_P, and sets the line obtained by moving the second predicted position determination line LIN2_P toward the lane LN side by the predicted lateral movement distance DIS_P as the second current position determination line LIN2_N.

[0124] Furthermore, as described above, the lane departure prevention device 10 can obtain the predicted lateral movement distance DIS_P by performing calculations according to the above-mentioned equation 2 based on the current vehicle speed SPD_N, the current lateral acceleration GY_N, and the predetermined time T.

[0125] <Effect>

[0126] 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 factors. Therefore, the predicted vehicle position POS_P sometimes reaches the first predicted position determination line LIN1_P first, and sometimes reaches the second predicted position determination line LIN2_P first. Therefore, in the case where the predicted vehicle position POS_P reaches the second predicted position determination line LIN2_P first, the predicted vehicle position POS_P has not reached the first predicted position determination line LIN1_P, and therefore, at the time point when the predicted vehicle position POS_P reaches the second predicted position determination line LIN2_P, the first deviation condition C_D1 does not hold, and therefore, the automatic steering control is not performed.

[0127] However, at this time, when the avoidable departure condition C_DP is satisfied, if the first departure condition C_D1 is satisfied, the automatic steering control is executed, and the lane departure of the host vehicle 100 is avoided by the automatic steering control. Therefore, even if the alarm control is not executed to prompt the driver DR to perform a driving operation (avoiding departure operation) for avoiding the lane departure of the host vehicle 100, in short, the first departure condition C_D1 is satisfied and the automatic steering control is started, and the lane departure of the host vehicle 100 can be avoided. Therefore, when the alarm control is executed in such a situation, there is a possibility that the driver DR will feel annoyed by the alarm issued by the alarm control.

[0128] According to the lane departure prevention device 10, when the alarm execution condition C_LDA is satisfied and the departure condition C_DP can be avoided, the alarm control is not executed. That is, the departure condition C_DP can be avoided, and therefore, in short, the first departure condition C_D1 is satisfied, and the automatic steering control is started, thereby avoiding the lane departure of the host vehicle 100. In this case, the alarm control is not executed. Therefore, the possibility of making the driver DR feel annoyed by the alarm issued by the alarm control can be reduced.

[0129] On the other hand, when the avoidable departure condition C_DP is not satisfied, even if the first departure condition C_D1 is satisfied, the automatic steering control is not executed, and therefore, there is no expected possibility of avoiding the lane departure of the host vehicle 100 by the automatic steering control. According to the lane departure prevention device 10, when the avoidable departure condition C_DP is not satisfied when the alarm execution condition C_LDA is satisfied, the alarm control is executed. Thus, the driver DR is prompted to perform a driving operation for avoiding the lane departure of the host vehicle 100. Therefore, even if the automatic steering control is not executed, the lane departure of the host vehicle 100 can be prevented by the driver DR who notices the alarm issued by the alarm control and spontaneously performs a driving operation for avoiding the lane departure of the host vehicle 100.

[0130] In addition, the lane departure prevention device 10 may be configured to execute the alarm control in such a way that the alarm level (alarm level LV) becomes lower than the predetermined alarm level LV_TH, instead of not executing the alarm control when the departure condition C_DP can be avoided when the alarm execution condition C_LDA is satisfied.

[0131] For example, the lane departure prevention device 10 may be configured to delay the timing of starting the warning control when the departure avoidable condition C_DP is satisfied when the warning execution condition C_LDA is satisfied, compared to when the departure avoidable condition C_DP is not satisfied when the warning execution condition C_LDA is satisfied.

[0132] In this case, for example, the lane departure prevention device 10 is configured to start the alarm control at the time when the alarm execution condition C_LDA is established when the avoidable departure condition C_DP is not established, but to start the alarm control at the time when the alarm execution condition C_LDA is established when the avoidable departure condition C_DP is established, and to start the alarm control at the time when a predetermined time (predetermined delay time T_DLY) has passed since the alarm execution condition C_LDA was established when the avoidable departure condition C_DP is established. That is, the lane departure prevention device 10 is configured to delay the timing of starting the alarm control when the avoidable departure condition C_DP is established and the alarm control is executed when the alarm execution condition C_LDA is established, compared with the case where the avoidable departure condition C_DP is not established when the alarm execution condition C_LDA is established.

[0133] Thus, the start of the warning control is delayed, and as a result, the execution period of the warning control is shortened, so the level of the warning issued by the warning control is reduced. Therefore, when it is expected that the lane departure of the vehicle 100 can be avoided by the automatic steering control, the possibility of the driver DR feeling annoyed by the warning issued by the warning control can be reduced.

[0134] Alternatively, the lane departure prevention device 10 may be configured to display an alarm and output an alarm sound when the alarm execution condition C_LDA is satisfied and the departure condition C_DP is avoided from not being satisfied, and to display an alarm and output an alarm vibration when the alarm execution condition C_LDA is satisfied and the departure condition C_DP is avoided from being satisfied.

[0135] Thus, when the alarm execution condition C_LDA is satisfied, the alarm display and the alarm vibration are performed to avoid the situation where the deviation condition C_DP is satisfied. Generally, the alarm vibration is lower than the alarm sound as the level of the alarm. When it is expected that the lane departure of the vehicle 100 can be avoided by the automatic steering control, the possibility of making the driver DR feel annoyed by the alarm issued by the alarm control can be reduced.

[0136] In addition, the deviation avoidable condition C_DP may also include the following condition: based on the lateral acceleration GY (predicted lateral acceleration GY_P) of the host vehicle 100 when the automatic steering control is assumed to start at this time point, the current vehicle speed SPD_N, the current vehicle position POS_N and the predetermined time T, the predicted vehicle position POS_P is obtained, and at the predicted vehicle position POS_P, the distance (maximum deviation distance DIS_MAX) by which the host vehicle 100 deviates from the lane dividing object 200 is shorter than the predetermined distance (maximum deviation distance threshold DIS_TH). In this case, the lane departure prevention device 10 obtains the predicted vehicle position POS_P by, for example, calculating 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.

[0137] POS_P=POS_N+SPD_N×T+1 / 2×GY_P×T 2 …(3)

[0138] Thus, only when the maximum deviation distance DIS_MAX is shorter than the maximum deviation distance threshold DIS_TH when the warning execution condition C_LDA is satisfied, a response of not executing the warning control or a response of executing the warning control by lowering the warning level is adopted.

[0139] Generally, if the host vehicle 100 greatly exceeds the lane demarcation object 200, it is preferred to implement an alarm to urge the driver DR to perform a deviation avoidance operation, but if the host vehicle 100 does not greatly exceed the lane demarcation object 200, there is no need to implement an alarm to urge the driver DR to perform a deviation avoidance operation. That is, when the maximum deviation distance DIS_MAX is shorter than the maximum deviation distance threshold DIS_TH, there is no need to implement an alarm to urge the driver DR to perform a deviation avoidance operation. Therefore, only when the maximum deviation distance DIS_MAX is shorter than the maximum deviation distance threshold DIS_TH when the alarm execution condition C_LDA is satisfied, the response of not executing the alarm control or executing the alarm control by lowering the alarm level is adopted, thereby reducing the possibility of making the driver DR feel annoyed by the alarm issued by the alarm control.

[0140] In addition, the deviation avoidable condition C_DP may also include a condition that the driver DR is in a state capable of driving the host vehicle 100. Here, the driver DR is in a state capable of driving the host vehicle 100, which means that the driver DR holds the portion of the steering wheel 35 suitable for the driving operation with both hands, the driver DR faces the steering wheel 35, and the driver DR's eyes are open (that is, the driver DR is awake).

[0141] Thus, since the departure avoidable condition C_DP includes the condition that the driver DR is in a state where the driving operation can be performed, the previously described response of not performing the warning control even if the warning execution condition C_LDA is satisfied or performing the warning control by lowering the level of the warning when the warning execution condition C_LDA is satisfied is only adopted when the driver DR is in a state where the driving operation can be performed when the host vehicle 100 is about to depart from the lane LN. Therefore, even if the warning control is not performed or the warning control is performed by lowering the level of the warning, it is possible to fully expect the driver DR to perform the departure avoidance operation, and thus the possibility of avoiding the lane departure of the host vehicle 100 can be ensured.

[0142] In addition, the deviation avoidable condition C_DP may also include the condition that the lane dividing object 200 is not a three-dimensional structure 202. Here, the three-dimensional structure 202 is, for example, Figure 6 The lane departure prevention device 10 can detect the three-dimensional structure 202 based on the surrounding detection information INF_D.

[0143] Thus, since the deviation condition C_DP can be avoided including the condition that the lane dividing object 200 is not the three-dimensional structure 202, the previously described response of not executing the alarm control even if the alarm execution condition C_LDA is satisfied or executing the alarm control by lowering the alarm level when the alarm execution condition C_LDA is satisfied is only adopted when the lane dividing object 200 is not the three-dimensional structure 202 when the host vehicle 100 is about to deviate from the lane LN. Therefore, even if the alarm control is not executed or the alarm control is executed by lowering the alarm level, the driving safety of the host vehicle 100 can be ensured.

[0144] In addition, the deviation avoidable condition C_DP may also include a condition that there is no object 300 that the host vehicle 100 may contact outside the lane dividing object 200. Figure 2 As shown, the object 300 is a pedestrian 301, another vehicle 302, etc. 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 in a predetermined range in front of the traveling direction of the host vehicle 100, it is determined that there is an object 300 outside the lane dividing object 200 that the host vehicle 100 may contact.

[0145] Thus, since the deviation avoidance condition C_DP includes the condition that there is no object 300 that the host vehicle 100 may contact outside the lane dividing object 200, the previously described response of not executing the alarm control even if the alarm execution condition C_LDA is satisfied or executing the alarm control by lowering the alarm level when the alarm execution condition C_LDA is satisfied is only adopted when the object 300 that the host vehicle 100 may collide with when the host vehicle 100 is about to deviate from the lane LN does not exist outside the lane dividing object 200. Therefore, even if the alarm control is not executed or the alarm control is executed by lowering the alarm level, the driving safety of the host vehicle 100 can be ensured.

[0146] <Specific Operation of Lane Departure Prevention Device>

[0147] 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 executes the following operation at a predetermined calculation cycle. Figure 7 Therefore, when the predetermined timing is reached, the CPU starts Figure 7 The routine shown starts processing at step 700, and the process proceeds to step 705 to acquire the predicted vehicle position POS_P. Next, the CPU proceeds to step 710 to set the first predicted position determination line LIN1_P. Next, the CPU proceeds to step 715 to determine whether the first deviation condition C_D1 is satisfied.

[0148] When the CPU makes a “yes” determination in step 715, the process proceeds to step 720 to determine whether the automatic steering permission condition C_AS is satisfied.

[0149] When the CPU determines "yes" in step 720, the CPU advances the process to step 725 to execute the automatic steering control. Then, the CPU advances the process to step 795 and temporarily ends this routine.

[0150] On the other hand, when the CPU makes a "No" determination in step 715 or step 720, the CPU directly proceeds to step 795 and temporarily terminates this routine.

[0151] Furthermore, the CPU executes the Figure 8 Therefore, when the predetermined timing is reached, the CPU starts Figure 8 The routine shown starts processing at step 800, and the process proceeds to step 805 to acquire the predicted vehicle position POS_P. Next, the CPU proceeds to step 810 to set the second predicted position determination line LIN2_P. Next, the CPU proceeds to step 815 to determine whether the alarm execution condition C_LDA is satisfied.

[0152] When the CPU determines "yes" in step 815, the processing proceeds to step 820 to determine whether automatic steering control is being executed.

[0153] When the CPU determines "yes" in step 820, the processing directly proceeds to step 895 and temporarily ends this routine. In this case, the alarm control is not executed.

[0154] On the other hand, when the CPU makes a "No" determination in step 820, the CPU advances the process to step 825 to determine whether the automatic steering permission condition C_AS is satisfied.

[0155] When the CPU determines "yes" in step 825, the processing directly proceeds to step 895 and temporarily ends this routine. In this case, the alarm control is not executed.

[0156] On the other hand, when the CPU makes a "No" determination in step 825, the CPU advances the process to step 830 to execute the alarm control. Next, the CPU advances the process to step 895 to temporarily terminate this routine.

[0157] In addition, when the CPU makes a "No" determination in step 815, the processing directly proceeds to step 895 and temporarily ends this routine.

[0158] Alternatively, the CPU may be configured to replace Figure 8 The routine shown is executed Fig. 9 In this case, when the predetermined timing is reached, the CPU starts Fig. 9 The routine shown starts processing at step 900, and the process proceeds to step 905 to acquire the predicted vehicle position POS_P. Next, the CPU proceeds to step 910 to set the second predicted position determination line LIN2_P. Next, the CPU proceeds to step 915 to determine whether the alarm execution condition C_LDA is satisfied.

[0159] When the CPU determines "yes" in step 915, the processing proceeds to step 920 to determine whether automatic steering control is being executed.

[0160] When the CPU determines "yes" in step 920, the processing directly proceeds to step 995 and temporarily ends this routine. In this case, the alarm control is not executed.

[0161] On the other hand, when the CPU makes a "No" determination in step 920, the CPU advances the process to step 925 to determine whether the automatic steering permission condition C_AS is satisfied.

[0162] If the CPU determines "yes" in step 925, the process proceeds to step 930, and performs alarm control to make the alarm level LV a level lower than the predetermined alarm level LV_TH. Then, the CPU directly proceeds to step 995, and temporarily terminates this routine. In this case, the alarm control of the predetermined alarm level LV_TH is not performed.

[0163] On the other hand, when the CPU makes a "No" determination in step 925, the CPU advances the processing to step 935 and executes alarm control to change the alarm level LV to a predetermined alarm level LV_TH. Next, the CPU advances the processing to step 995 and temporarily terminates this routine.

[0164] In addition, when the CPU makes a "No" determination in step 915, the processing directly proceeds to step 995 and temporarily ends this routine.

[0165] The above is the specific operation of the lane departure prevention device 10 .

[0166] In addition, the present invention is not limited to the above-described embodiment, and various modifications can be adopted within the scope of the present invention.< / ecu>

Claims

1. A lane departure prevention device, the lane departure prevention device comprising a control device, the control device executing: an alarm control for notifying a driver of a host vehicle that the host vehicle may deviate from a lane; and an automatic steering control for automatically applying a steering force to the host vehicle that may deviate from the lane to automatically steer the host vehicle back to the lane, wherein: The control device is configured as follows: When a lane departure condition is satisfied while an automatic steering permission condition is satisfied, executing the automatic steering control; When the automatic steering control is not executed when the alarm execution condition is satisfied, and when the deviation avoidable condition that is satisfied when the automatic steering permission condition is satisfied is not satisfied, the alarm control is executed so that the level of the alarm becomes a predetermined alarm level. If the automatic steering control is not executed when the alarm execution condition is satisfied, the alarm control is not executed when the departure avoidable condition is satisfied, or the alarm control is executed so that the level of the alarm becomes a level lower than the predetermined alarm level.

2. The lane departure prevention device according to claim 1, wherein: The departure avoidable condition includes a condition that the driver of the host vehicle is in a state where he can perform a driving operation on the host vehicle.

3. The lane departure prevention device according to claim 1 or 2, wherein: The departure avoidable condition includes a condition that the dividing object dividing the lane is not a three-dimensional structure.

4. The lane departure prevention device according to any one of claims 1 to 3, wherein: The departure avoidable condition includes a condition that there is no object with which the host vehicle may come into contact outside a partition that partitions the lane.

5. The lane departure prevention device according to any one of claims 1 to 4, wherein: The control device is configured to delay timing of starting the alarm control when the alarm execution condition is satisfied and the avoidable deviation condition is satisfied and the alarm control is executed, compared to when the alarm execution condition is satisfied and the avoidable deviation condition is not satisfied.

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