Driving assistance systems

Abstract

The present invention provides a driver assistance system that can seamlessly perform lane departure prevention processing and lane centering processing. [Solution] In the process of executing a recovery process to return the vehicle to lane L0 from a state in which the vehicle has deviated from lane L0, the ECU 10 of the driving support device 1 sequentially acquires target values ​​as first target values ​​for physical quantities related to the behavior of the vehicle's steering system or the behavior of the vehicle's body when the recovery process is continued while the vehicle is moving toward the inside of lane L0, and also sequentially acquires target values ​​as second target values ​​for the physical quantities necessary to move the vehicle along the center line C of lane L0, assuming that the lane centering process has started, and when the difference between the first target value θt1 and the second target value is less than or equal to a threshold, it interrupts the recovery process and executes a transition process to start the lane centering process.

Description

Technical Field

[0001] The present invention relates to a driving support device having a function of controlling the host vehicle so as to suppress the host vehicle from departing from the lane in which the host vehicle is traveling, and a function of controlling the host vehicle so as to travel along the lateral center line of the lane in which the host vehicle is traveling.

Background Art

[0002] A driving support device having a function of controlling the host vehicle so as to suppress the host vehicle from departing from the lane in which the host vehicle is traveling (lane departure suppression function) and a function of controlling the host vehicle so as to travel along the lateral center line of the lane in which the host vehicle is traveling (lane center traveling function) has been proposed (for example, refer to Patent Document 1 below). When the processor of this device (hereinafter referred to as "conventional device") determines that there is a high possibility that the host vehicle will depart from the lane based on information acquired from sensors such as a camera and a radar, the processor executes a process of controlling the steering device so that the departure is suppressed. Even if the processor executes the process, a part of the host vehicle may depart from the lane. When the processor detects that a part of the host vehicle has departed from the lane (the host vehicle is straddling the lane marking line) based on the information acquired from the same sensor, the processor controls the steering device of the host vehicle so that the host vehicle returns to the original lane, and after the host vehicle returns to the original lane, further executes a process of controlling the steering device so that the longitudinal direction of the host vehicle and the extending direction of the lane are substantially parallel (lane departure suppression process). Further, in a state where the entire host vehicle is within the lane, when the processor of the conventional device detects that the host vehicle (for example, the center of gravity) is deviated from the lateral center line of the lane based on the information acquired from the same sensor, the processor executes a process of controlling the steering device so that the host vehicle (center of gravity) moves toward the center line side, and the longitudinal direction of the host vehicle coincides with the extending direction of the center line (lane center traveling process).

Prior Art Documents

Patent Documents

[0003] [Patent Document 1] Japanese Patent Publication No. 2018-079835 [Overview of the project]

[0004] Conventional devices have a processor that, when it performs lane departure prevention processing, starts lane centering processing from the moment that processing is completed. That is, if the vehicle is straddling the lane markings, the processor rotates the steering wheel in a first direction (for example, counterclockwise) so that the vehicle moves back towards the original lane. Next, when the entire (or most) of the vehicle has returned to the original lane (is located at the edge of the lane), the processor rotates the steering wheel in a second direction, opposite to the first direction. Then, when the longitudinal direction of the vehicle and the direction of lane extension are approximately parallel (or when the steering wheel is slightly pointed towards the center line of the lane), the processor completes the lane departure prevention processing and starts lane centering processing. That is, the processor rotates the steering wheel back to the first direction so that the vehicle moves from the edge of the lane towards the center line of the lane. This kind of vehicle behavior (where the lane departure prevention process and the lane centering process appear to be executed sequentially) may cause discomfort to the driver.

[0005] One of the objectives of the present invention is to provide a driver assistance device that can seamlessly perform lane departure prevention processing and lane centering processing.

[0006] To achieve the above objective, the driving assistance device (1) of the present invention is: A surrounding sensor (21) for acquiring the lateral position (ΔDL, ΔDR, Δd) of the vehicle in the lane (L0) in which the vehicle is traveling and the attitude (α, β) of the vehicle relative to the lane, A processor (10) for controlling the vehicle, A lane departure suppression process that includes a return process to control the steering device (30) based on a target value, and sequentially determines a target value for a physical quantity (θ) related to the behavior of the vehicle's steering device (30) or the behavior of the vehicle's body as a first target value (θt1), and controls the steering device (30) based on the target value, so that the entire vehicle returns to the lane and transitions from a state in which a part of the vehicle has deviated outside the lane beyond the lane's lateral boundary line (BR, BL) to a state in which the vehicle's direction of travel is parallel to the direction of the lane's extension, and The lane centering process involves sequentially determining a second target value (θt2) for the target value of the physical quantity so that the vehicle moves along a center line passing through the center of the lane in the lateral direction, and controlling the steering device based on the second target value. A processor configured to run, It is equipped with. The processor is configured to sequentially acquire the first target value when the recovery process is continued while the vehicle is moving towards the inside of the lane, and to sequentially acquire the second target value assuming that the lane centering driving process has started, and if the difference (Δθt) between the first target value and the second target value is less than or equal to a threshold (Δθtth), to interrupt the lane departure suppression process and execute a transition process to start the lane centering driving process.

[0007] As described above, in conventional devices, lane departure prevention processing is performed from the point when the lane departure prevention processing is completed (when the steering wheel is returned to the neutral position (or when the steering wheel is slightly turned toward the center line of the lane)). In contrast, the processor of the driver assistance device according to the present invention interrupts the lane departure prevention processing and starts lane centering processing if the target value of the steering angle determined by the lane departure prevention processing when the lane departure prevention processing is continued during the recovery process is approximately the same as the target value of the steering angle determined by the lane centering processing when the lane centering processing is started. In other words, lane centering processing is started before the steering wheel is returned to the approximately neutral position. Therefore, the switch from lane departure prevention processing to lane centering processing is performed without any sense of incongruity. That is, the driver gets the impression that the lane departure prevention processing and the lane centering processing are performed as a single driver assistance process. In short, according to the present invention, the lane departure prevention processing and the lane centering processing are performed seamlessly.

[0008] In a driving support device according to one aspect of the present invention, The aforementioned physical quantity is the steering angle of the steering wheel.

[0009] According to this, the driver's discomfort with the changes in the rotation angle and position of the steering wheel during the transition process from lane departure prevention processing (return processing) to lane centering processing is reduced.

[0010] In another aspect of the present invention, in a driving support device, The processor can execute the transition process if, during the execution of the recovery process, a predetermined condition is met for determining that the vehicle can be moved along the center line by the lane centering process while the vehicle is moving towards the inside of the lane.

[0011] In the driver assistance system according to this embodiment, the processor continues lane departure prevention processing if it is predicted that the vehicle cannot be moved along the center line of the lane even after starting the lane centering process. That is, the vehicle is automatically steered until the longitudinal direction of the vehicle and the direction of lane extension are approximately parallel.

[0012] In another aspect of the present invention, in a driving support device, The processor determines that the predetermined condition is met when it is unable to recognize the lane markings on the other end of the lane.

[0013] According to the driver assistance system of this embodiment, in situations where the center line of the lane cannot be accurately defined, the transition from lane departure prevention processing to lane center driving processing is prohibited.

[0014] In another aspect of the present invention, in a driving support device, The system includes an operating device used by the driver to select between an enabled and disabled state for the lane centering function, which is a function that performs the lane centering process. The processor can execute the transition process when the lane centering function is enabled by the operating device.

[0015] According to this, the driver can choose between a state where the transition process is permitted and a state where it is prohibited. [Brief explanation of the drawing]

[0016] [Figure 1] Figure 1 is a block diagram of a driver assistance device according to one embodiment of the present invention. [Figure 2] Figure 2 is a plan view showing an example of the vehicle's trajectory when lane departure prevention processing is performed. [Figure 3] Figure 3 is a plan view showing an example of the vehicle's trajectory when the processor starts lane centering driving processing from the point when it completes lane departure prevention processing (return processing). [Figure 4]FIG. 4 is a plan view showing an example of the trajectory of the host vehicle when a processor interrupts lane departure suppression processing (return processing) and starts lane center traveling processing from that point in time. [Figure 5] FIG. 5 is a flowchart of a program executed by the processor to realize the function of interrupting the lane departure suppression processing and starting the lane center traveling processing. [Mode for Carrying Out the Invention]

[0017] (Outline) As shown in FIG. 1, a driving support device 1 according to an embodiment of the present invention is applied to a vehicle V0. The vehicle V0 (hereinafter referred to as "host vehicle") has an automated driving function. The driving support device 1 has a lane departure suppression function that performs automatic steering such that the entire host vehicle returns into a lane L0 in which the host vehicle is traveling, in a situation (manual driving mode) where the automated driving function of the host vehicle is disabled and a driver is performing a manual driving operation, when the host vehicle is straddling a marking line BR (BL) between the lane L0 and a lane L1 adjacent to the lane L0 (see FIG. 2). Further, in the manual driving mode, the driving support device 1 has a lane center traveling function that performs automatic steering such that a reference point (for example, the center of gravity) of the host vehicle travels along a center line C (the reference point traces the center line C) when the entire host vehicle is within the lane L0 and the reference point is deviated laterally from a lateral center position (the center line C) of the lane L0. Note that the steering wheel SW is automatically operated during a period in which the lane departure suppression function is operating and a period in which the lane center traveling function is operating, and the driver needs to lightly grip the steering wheel SW in preparation for an emergency situation.

[0018] (Specific Configuration) Next, the configuration of the driving support device 1 will be specifically described. As shown in FIG. 1, the driving support device 1 includes an ECU 10, an in-vehicle sensor 20, and a steering device 30.

[0019] The ECU 10 includes a microcomputer equipped with a CPU 10a, a ROM 10b, a RAM 10c, a timer 10d, and the like. The ECU 10 is connected to other ECUs via a CAN (communication network).

[0020] The in-vehicle sensor 20 includes a camera 21 serving as an ambient sensor for acquiring information related to targets located around the host vehicle. Further, the in-vehicle sensor 20 includes a speed sensor 22 serving as a vehicle sensor for acquiring information related to the behavior of the host vehicle. In addition, the in-vehicle sensor 20 includes a user interface 23 serving as an operation device used to select an enabled state or a disabled state of functions of various devices provided in the host vehicle.

[0021] The camera 21 includes an imaging device. The imaging device incorporates an imaging element such as a CCD (charge coupled device) or a CIS (CMOS image sensor), for example. The imaging device is installed, for example, at the front portion of the host vehicle. The imaging device captures an image of the area in front of the host vehicle at a predetermined frame rate to acquire image data. The camera 21 further includes an image analysis device. The image analysis device sequentially acquires image data from each imaging device. The image analysis device analyzes the acquired image data, and acquires information related to targets located in the periphery (front) of the host vehicle from the image. For example, the image analysis device recognizes a pair of left and right marking lines BL and BR that demarcate the lane L0 in which the host vehicle is traveling and the lane L1 adjacent to the lane L0, and acquires the positions of the marking lines BL and BR (for example, the coordinates of the end points in the extending direction of the marking lines BL and BR in the image (the end point on the side closer to the host vehicle and the end point on the side farther from the host vehicle)). Further, the image analysis device acquires the curvature (curve radius) of the lane L0 based on the shapes of the marking lines BL and BR in the image. The image analysis device provides the acquired information (coordinates and curvature) to the ECU 10 as marking line information (target information).

[0022] The speed sensor 22 detects the rotational speed (wheel speed) of each wheel, and calculates the speed sp0 (actual measured value) of the host vehicle based on each wheel speed. The speed sensor 22 provides the calculation result to the ECU 10.

[0023] The user interface 23 includes an image display device and a touch panel. The image display device receives an image display command from the ECU 10 and displays an image according to the command. For example, it can display images (icons) used to select between the enabled and disabled states of the lane departure prevention function and the lane centering function. Each time the driver taps the icon (the area of ​​the touch panel that overlaps the icon), the enabled and disabled states of each function are alternately switched. Alternatively, the user interface 23 may include switches, levers, etc., used to select between the enabled and disabled states of each function instead of the image display device and touch panel.

[0024] The steering device 30 has a function to automatically adjust the rotational angle position (steering angle θ) of the steering wheel SW (automatic steering function). As components to realize this function, the steering device 30 includes a steering ECU and a steering mechanism. The steering mechanism includes a link mechanism that connects the steering wheel SW and the steering wheel. The steering device 30 further includes an actuator (e.g., an electric motor) that drives the steering mechanism to change the rotational angle position (steering angle θ) of the steering wheel SW, and a steering angle sensor that acquires the steering angle θ. The ECU 10 determines a target value θt of the steering angle θ based on various information acquired from the on-board sensor 20. For example, when the lane centering function is enabled, the ECU 10 sequentially calculates (updates) the target value θt so that the reference point of the vehicle moves along the center line C of lane L0. The steering ECU acquires the target value θt from the ECU 10 and controls the actuator so that the value output from the steering angle sensor matches the target value θt.

[0025] (Lane departure prevention function) When the lane departure prevention function is enabled, the ECU10 performs the following lane departure prevention process. The lane departure prevention process includes avoidance and recovery processes.

[0026] (Avoidance process) The ECU 10 sequentially determines whether the following conditions XR and XL are met based on the coordinates of the lane markings BL and BR obtained from the on-board sensor 20, and the speed sp0. Condition XR: The time TLC required for the vehicle to deviate from lane L0 by crossing the lane marking BR (for part of the vehicle to enter lane L1 adjacent to the right of lane L0) is less than or equal to the threshold TLCth. Condition XL: The time TLC required for the vehicle to deviate from lane L0 beyond lane marking BL (for part of the vehicle to enter lane L1 adjacent to the left of lane L0) is less than or equal to the threshold TLCth. Here, ECU10 obtains the time TLC by executing the following process. Based on the lane marking information obtained from camera 21, ECU10 obtains the vehicle's attitude relative to lane L0 (angle α between the vehicle's longitudinal direction and lane L0). Next, based on the same lane marking information, ECU10 obtains the vehicle's position in the lateral direction of lane L0 (distance ΔDR between the right end of the vehicle's front surface and lane marking BR, and distance ΔDL between the left end of the vehicle's front surface and lane marking BL). Next, based on the velocity sp0 and angle α, ECU10 obtains the vehicle's lateral velocity spy (=sp0 × sinα). Next, if the vehicle is heading towards lane marking BR, ECU10 obtains the value obtained by dividing the distance ΔDR by the lateral velocity spy as the time TLC. On the other hand, if the vehicle is heading towards lane marking BL, ECU10 obtains the value obtained by dividing the distance ΔDL by the lateral velocity spy as the time TLC.

[0027] If the ECU 10 determines that condition XR or condition XL is met, it determines a target value θt for the steering angle θ such that the angle α becomes smaller. Here, in order to maintain a high level of occupant comfort, the ECU 10 determines the target value θt such that the lateral acceleration of the vehicle is below a predetermined upper limit. That is, the larger the speed sp0, the smaller the value assigned to the target value θt. For example, a predetermined map that defines the relationship between speed sp0 and the value assigned to the target value θt is pre-stored in the ROM 10b. The ECU 10 refers to this map to obtain the value to be assigned to the target value θt (right steering angle and left steering angle).

[0028] The above avoidance process is expected to increase the time TLC. The ECU 10 sequentially calculates the time TLC while executing the avoidance process. The ECU 10 completes the avoidance process (lane departure suppression process) when the entire vehicle is within lane L0 and the time TLC exceeds the threshold TLCth (or a predetermined value greater than the threshold TLC). Alternatively, the ECU 10 may complete the avoidance process (lane departure suppression process) when the longitudinal direction of the vehicle and the extension direction of lane L0 are approximately parallel. Alternatively, the ECU 10 may complete the avoidance process (lane departure suppression process) when the vehicle is slightly turned towards the center line C.

[0029] Incidentally, as mentioned above, the target value θt is determined according to the speed sp0. Therefore, when the speed sp0 is relatively large, the steering angle θ is relatively small. As a result, as shown in Figure 2, even if the avoidance process is executed, a part of the vehicle may deviate from lane L0. In this case, the ECU 10 executes the recovery process described below.

[0030] (Recovery process) The steering device 30 is controlled so that the entire vehicle returns to lane L0. Specifically, the ECU 10 sequentially calculates (updates) a target value θt so that the vehicle moves inward from lane L0 based on information acquired from the camera 21 and speed sensor 22, and transmits the target value θt to the steering ECU each time it is updated. For example, in a situation where part of the vehicle has entered lane L1 to the right (left) of lane L0, the ECU 10 assigns a larger value to the target value θt for the left steering angle (right steering angle) as the angle α between the extension direction of lane L0 (tangent to the current point in a curved road) and the direction of travel of the vehicle (direction toward the outside of lane L0) is larger. Furthermore, in a situation where part of the vehicle is entering the right (left) lane L1 of lane L0, the ECU 10 assigns a larger value to the target value θt for the left steering angle (right steering angle) as the lateral distance Δd, which is the distance between the vehicle (center of gravity) and the center line C of lane L0, is larger. Here, the ECU 10 sets the upper limit θmax of the target value θt for the left steering angle (right steering angle) according to the speed sp0, so that the lateral acceleration of the vehicle is below the upper limit. In other words, the ECU 10 assigns a smaller value to the upper limit θmax of the target value θt for the right steering angle (left steering angle) as the speed sp0 is larger.

[0031] However, if the lane departure prevention process is terminated when the vehicle is moving inward towards lane L0 and the entire vehicle has returned to lane L0 (when the front end of the vehicle is facing the center line C), there is a risk that the vehicle will continue moving beyond the center line C and enter lane L1 adjacent to the other end of lane L0 (a risk of a new lane departure). Therefore, from the moment the ECU 10 detects that the entire vehicle (or most of it (e.g., 80%)) has returned to lane L0, it sequentially calculates (updates) the target value θt so that the longitudinal direction of the vehicle and the extension direction of lane L0 are approximately parallel, and transmits the target value θt to the steering device 30 each time it is updated. The ECU 10 completes the return process (lane departure prevention process) when the longitudinal direction of the vehicle and the extension direction of lane L0 are approximately parallel. Furthermore, the ECU10 may complete the return process (lane departure prevention process) when the vehicle is slightly turned toward the center line C.

[0032] For example, in the example shown in Figure 2, a portion of the vehicle enters (deviates from) lane L1 on the right. In this example, the steering wheel switch is rotated counterclockwise from the neutral position, causing the vehicle to move to the left (turn). Then, once the entire vehicle (most of it) returns to lane L0, the steering wheel switch is rotated clockwise, causing the vehicle to move slightly to the right (turn). As the vehicle's longitudinal direction approaches a state where it is approximately parallel to the extension direction of lane L0, the steering wheel switch is gradually returned to the neutral position, and the lane departure prevention process is completed.

[0033] (Lane centering function) When the lane centering function is enabled and lane departure prevention processing is not being performed, the ECU 10 determines whether the following condition Y is met based on the coordinates of the lane markings BL and BR obtained from the camera 21. Condition Y: The entire vehicle is contained within lane L0, and the vehicle's center of gravity is offset laterally from the center line C. When the ECU 10 determines that condition Y is met, it sequentially calculates (updates) the target value θt so that the vehicle moves toward the center line C, and transmits the updated target value θt to the steering ECU each time it is updated. Specifically, when the vehicle's center of gravity is located to the right (left) of the center line C, the larger the lateral distance Δd, the larger the value assigned to the target value θt for the left steering angle (right steering angle). This causes the lateral distance Δd to begin to decrease. As the lateral distance Δd decreases, the ECU 10 reduces the value assigned to the target value θt for the left steering angle (right steering angle) and returns the steering wheel SW to the neutral position (θt=0). If the vehicle continues to move in this manner, there is a risk that the vehicle (center of gravity) will cross the center line C. Therefore, from the moment the ECU 10 detects that the lateral distance Δd has fallen below the threshold Δdth, it assigns a relatively small value to the target value θt for the right steering angle (left steering angle). As a result, the angle β between the longitudinal direction of the vehicle and the extension direction of the centerline C decreases. Then, when the longitudinal direction of the vehicle and the extension direction of the centerline C become approximately parallel, the ECU 10 decreases the target value θt and returns the steering wheel SW to the neutral position. Furthermore, when the vehicle is traveling on a curved road, the ECU 10 controls the steering device 30 so that the steering angle θ corresponding to the curvature of the lane L0 acquired from the camera 21 is maintained.

[0034] For example, in the example shown in Figure 3, the lane centering process begins when the vehicle's center of gravity is located to the right of the center line C. At this point (immediately after the lane centering process begins), the steering wheel SW rotates counterclockwise from the neutral position, causing the vehicle to move (turn) to the left. As the vehicle's center of gravity approaches the center line C, the steering wheel SW returns to the neutral position. Subsequently, once the center of gravity is somewhat close to the center line C, the steering wheel SW rotates clockwise, causing the vehicle to move (turn) slightly to the right, so that the vehicle's center of gravity aligns with the center line C, and the vehicle's longitudinal direction becomes parallel to the extension direction of the lane L0.

[0035] If the ECU 10 is configured to start the lane centering process from the moment the recovery process is completed, as shown in Figure 3, the steering wheel SW is controlled as follows: When the vehicle is straddling the lane marking BR (BL), the steering wheel SW is rotated counterclockwise (clockwise) to move towards the inside of lane L0. Next, when the entire (or most) of the vehicle has returned to the lane L0 (located at one end of lane L0), the ECU 10 rotates the steering wheel SW clockwise (counterclockwise). Then, when the longitudinal direction of the vehicle and the extension direction of lane L0 become approximately parallel, the recovery process is completed and the lane centering process begins. That is, the steering wheel SW is rotated counterclockwise (clockwise) again. In this way, the steering wheel SW's rotation direction is switched many times, giving the driver the impression that the lane departure prevention process and the lane centering process are executed sequentially.

[0036] Therefore, as shown in Figure 4, the ECU10 performs the following process (transition process) during the period T after the point in time when the entire vehicle (most of it) has returned to lane L0, in the process of executing the lane departure prevention process.

[0037] (Migration process) The ECU10 determines whether condition Z is met by determining that it can move its vehicle along the center line C through lane centering processing (i.e., it is possible to define the center line C as the target driving line). Condition Z: Camera 21 is able to recognize lane markings BR and BL (a pair of lane markings on the left and right sides of lane L0).

[0038] When condition Z is met, the ECU 10 sequentially acquires the target value θt that would occur if the lane departure prevention process were continued as the first target value θt1, and simultaneously acquires the target value θt determined by the lane centering process as the second target value θt2, assuming that the lane centering process has started. Then, if the difference Δθt (=|θt1―θt2|) between the first target value θt1 and the second target value θt2 is less than or equal to the threshold θtth, the ECU 10 interrupts the lane departure prevention process and starts the lane centering process. As a result, the lane departure prevention process and the lane centering process are executed seamlessly. In other words, the lane centering process starts before the steering wheel SW is returned to the neutral position.

[0039] Next, referring to Figure 5, we will explain the program PR1 executed by the CPU 10a (hereinafter simply referred to as "CPU") to realize the above-mentioned function of the driver assistance device 1 (the function of seamlessly executing lane departure prevention processing and lane centering driving processing (transition processing)). The ECU 10 executes program PR1 at predetermined intervals when it is performing recovery processing and the entire vehicle is within lane L0.

[0040] (Program PR1) The CPU starts executing program PR1 from step 100 and proceeds to step 101.

[0041] In step 101, the CPU determines whether the lane centering function is enabled (i.e., the function is enabled using the user interface 23). If the ECU 10 determines that the lane centering function is enabled (101: Yes), it proceeds to step 102. On the other hand, if the ECU 10 does not determine that the lane centering function is enabled (101: No), it proceeds to step 107.

[0042] In step 102, the CPU determines whether it can move its vehicle along the center line C by lane centering processing (whether condition Z is met or not). If the CPU determines that it can move its vehicle along the center line C by lane centering processing (102: Yes), it proceeds to step 103. On the other hand, if the CPU does not determine that it can move its vehicle along the center line C by lane centering processing (102: No), it proceeds to step 107.

[0043] In step 103, the CPU determines whether or not it is currently performing a recovery process. If the CPU determines that it is currently performing a recovery process (103: Yes), it proceeds to step 104. On the other hand, if the CPU does not determine that it is currently performing a recovery process (103: No), it proceeds to step 107.

[0044] In step 104, the CPU obtains the difference Δθt between the first target value θt1 and the second target value θt2, and determines whether the difference Δθt is less than or equal to the threshold Δθtth. If the CPU determines that the difference Δθt is less than or equal to the threshold Δθtth (104: Yes), it proceeds to step 105. On the other hand, if the CPU does not determine that the difference Δθt is less than or equal to the threshold Δθtth (104: No), it returns to step 103.

[0045] In step 105, the CPU interrupts the lane departure prevention process (recovery process). The CPU then proceeds to step 106.

[0046] In step 106, the CPU starts the lane centering process. This transitions the vehicle from lane departure prevention to lane centering. Next, the CPU proceeds to step 107.

[0047] The CPU terminates the execution of program PR1 in step 107.

[0048] (effect) As described above, in conventional devices, lane departure prevention processing is performed from the point when the lane departure prevention processing is completed (when the steering wheel SW is returned to the approximately neutral position). In contrast, the ECU 10 of the driver assistance device 1 according to this embodiment interrupts the lane departure prevention processing and starts lane centering processing when the target value of the steering angle θ determined by the lane departure prevention processing (first target value θt1) determined when the lane centering processing is continued during the return process is approximately the same as the target value of the steering angle θ determined by the lane centering processing (second target value θt2) determined when the lane centering processing is started (|θt1―θt2|≦θtth). Therefore, the switch from lane departure prevention processing to lane centering processing is performed without any sense of incongruity. That is, the driver gets the impression that the lane departure prevention processing and the lane centering processing are performed as a single driver assistance processing. In other words, according to the present invention, the lane departure prevention processing and the lane centering processing are performed seamlessly.

[0049] (modified version) In the above embodiment, the steering device 30 is controlled so that the steering angle θ (a physical quantity related to the behavior of the steering device 30) matches a target value during lane departure prevention processing and lane centering processing. Alternatively, the steering device 30 may be controlled so that the actual steering angle (a physical quantity related to the behavior of the steering device 30) or yaw rate (a physical quantity related to the behavior of the vehicle body) of the vehicle matches a target value during lane departure prevention processing and lane centering processing. [Explanation of Symbols]

[0050] 1...Driving assistance system, 10...ECU, 20...On-board sensor, 30...Steering system

Claims

1. Surrounding sensors for acquiring the lateral position of the vehicle in the lane in which the vehicle is traveling and the attitude of the vehicle relative to the lane, A processor for controlling the vehicle, A lane departure suppression process that includes a return process to control the steering system based on a target value, sequentially determining a target value for a physical quantity related to the behavior of the vehicle's steering system or the vehicle's body, so that the entire vehicle returns to the lane and the direction of travel of the vehicle is parallel to the direction of extension of the lane, from a state in which a part of the vehicle has deviated outside the lane by exceeding the lane marking on one end of the lane in the lateral direction, and to a state in which the entire vehicle returns to the lane and the direction of travel of the vehicle is parallel to the direction of extension of the lane, and The lane centering process involves sequentially determining a target value for the physical quantity as a second target value so that the vehicle moves along a center line passing through the center of the lane in the lateral direction, and controlling the steering device based on the second target value. A processor configured to run, A driver assistance device equipped with, The processor is configured to sequentially acquire the first target value when the recovery process is continued while the vehicle is moving towards the inside of the lane, and to sequentially acquire the second target value assuming that the lane centering driving process has started, and if the difference between the first target value and the second target value is less than or equal to a threshold, to interrupt the lane departure suppression process and execute a transition process to start the lane centering driving process.

2. In the driving support device according to claim 1, The aforementioned physical quantity is the steering angle of the steering wheel, in a driver assistance device.

3. In the driving support device according to claim 1, The processor is configured to execute the transition process when, during the execution of the recovery process, a predetermined condition is met for determining that the vehicle can be moved along the center line by the lane centering process while the vehicle is moving towards the inside of the lane.

4. In the driving support device according to claim 3, The driver assistance device is configured such that the processor determines that the predetermined condition is met when the lane markings on the other end of the lane cannot be recognized.

5. In the driving support device according to any one of claims 1 to 4, The system includes an operating device used by the driver to select between an enabled and disabled state for the lane centering function, which is a function that performs the lane centering process. The driver assistance device is configured such that the processor can perform the transition process when the lane centering function is enabled by the operating device.

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