Lane departure suppression control device

Abstract

The present application provides a lane departure suppression control device, even when the lane departure suppression control continues, if the driver performs steering override in the direction opposite to the lane departure direction, it can perform smooth steering assistance that does not bring discomfort to the driver. In the case of detecting the steering override of the driver in the lane departure suppression control (S22) and in the case of determining that the steering wheel operation direction is located in the return direction opposite to the lane departure direction of the vehicle (1) (S24), the target steering angle θo set for lane departure suppression is set in a manner more to the wheel direction than the actual steering angle θst generated by the steering wheel operation of the driver, thereby actively assisting the steering wheel operation of the driver (S29).

Description

Technical Field

[0001] This invention relates to a lane departure suppression control device that assists the driver in steering wheel operation when the driver has oversteered in the direction of lane return while the lane departure suppression control unit is performing lane departure suppression control. Background Technology

[0002] Previously, this type of lane departure suppression control device first used sensors such as cameras mounted on the vehicle to identify the vehicle's driving lane. When it was determined that the vehicle's direction of travel tended to deviate from the driving lane, the steering assist torque was controlled to make the vehicle parallel to the lane markings, thereby preventing the vehicle from deviating from the driving lane.

[0003] When the steering assist torque is stable, it generates steering torque in the direction that assists the driver in steering wheel operation; however, when lane departure suppression control is in operation, it generates steering torque in the direction that suppresses or prevents the vehicle from deviating from its lane.

[0004] Furthermore, the steering assist torque during lane departure mitigation control is set to a relatively large value to minimize the impact of external disturbances. Therefore, even if the driver intends to operate the steering wheel in the opposite direction of the steering assist, i.e., the direction of lane departure, a strong reaction force will be applied to the driver's steering wheel operation, resulting in discomfort.

[0005] As a countermeasure, for example, Patent Document 1 (Japanese Patent Application Publication No. 2018-114806) discloses the following technology: when the driver makes an intentional steering wheel operation in the direction of deviation, the steering assist torque being applied to prevent lane departure is reduced, thereby reducing the driver's discomfort from steering wheel operation.

[0006] Existing technical documents

[0007] Patent documents

[0008] Patent Document 1: Japanese Patent Application Publication No. 2018-114806 Summary of the Invention

[0009] Technical issues

[0010] When the vehicle is traveling at high speed on a curve with a short radius of curvature, for example, it is prone to deviating from the lane markings due to the large lateral acceleration generated. In such a situation, if the driver's steering wheel operation in the direction of deviation is detected and the steering assist torque applied to prevent lane departure is reduced, the lane departure will increase.

[0011] Therefore, it is considered preferable to maintain steering assist torque under such circumstances, even if it goes against the driver's wishes.

[0012] In addition, conventional lane departure mitigation control typically involves slightly turning the vehicle toward the center of the lane after the vehicle's posture becomes roughly parallel to the inside of the lane departure direction dividing line, and then ending the lane departure mitigation control.

[0013] However, when driving on curves like those described above, if lane departure suppression control ends relatively early after the vehicle's attitude becomes approximately parallel to the inside of the lane divider, a second lane departure may occur. Therefore, recently, even after the vehicle's attitude becomes approximately parallel to the inside of the lane divider, lane departure suppression control is maintained for a predetermined time (approximately 8 to 12 seconds), during which time the vehicle is driven along the inside of the lane divider to prevent a second lane departure.

[0014] Such lane departure mitigation control, which keeps the vehicle within the lane markings, can sometimes feel very long to the driver. As a result, it is perceived that the driver will engage in steering overdrive during lane departure mitigation control, using their own steering wheel to return the vehicle to the center of the lane.

[0015] Such steering overdrive guides the vehicle's control in the opposite direction to the deviation direction. Although the possibility of deviating again is low, in the technology disclosed in the above-mentioned documents, the strong steering assist torque that maintains a counterforce on the driver's steering wheel operation can cause discomfort to the driver.

[0016] In view of the above-mentioned problems, the present invention aims to provide a lane departure suppression control device that can perform steering wheel operations without causing discomfort to the driver when the driver has made a steering overrun in the direction opposite to the direction of lane departure while lane departure suppression control is in progress.

[0017] Technical solution

[0018] This invention comprises: a driving environment recognition unit that recognizes the driving environment in front of a vehicle and detects left and right lane markings dividing the lane in which the vehicle is traveling based on the recognized driving environment; a steering angle detection unit that detects the actual steering angle based on the driver's steering wheel operation; a vehicle behavior detection unit that detects the behavior of the vehicle; a lane departure prediction determination unit that predicts whether the vehicle will deviate from the lane based on the left and right lane markings detected by the driving environment recognition unit and the behavior of the vehicle detected by the vehicle behavior detection unit; and a lane departure suppression control unit that, when the lane departure prediction determination unit predicts that the vehicle will deviate from the lane... In the event of lane departure, a target steering angle is set to suppress the vehicle from deviating from the lane, and lane departure suppression control is performed; and a steering overshoot determination unit investigates whether there is steering overshoot based on the driver's steering wheel operation when the target steering angle is set by the lane departure suppression control unit. In the lane departure suppression control device, if the lane departure suppression control unit determines that the steering overshoot determination unit has detected steering overshoot and the target steering angle is in the return wheel direction relative to the actual steering angle detected by the steering angle detection unit, the target steering angle is set in a direction that assists the driver's steering wheel operation.

[0019] Technical effect

[0020] According to the present invention, in lane departure suppression control, when steering overshoot is detected in the direction opposite to the lane departure direction and it is determined that the target steering angle is located in the return wheel direction relative to the actual steering angle, the target steering angle is set in the direction that actively assists the driver's steering wheel operation, so that the driver can perform smooth steering wheel operation without discomfort. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the main components of a vehicle equipped with a lane departure mitigation control system.

[0022] Figure 2 This is a functional block diagram of the camera unit.

[0023] Figure 3 This is a functional block diagram of the lane departure suppression control device.

[0024] Figure 4 This is a flowchart illustrating the lane departure determination procedure.

[0025] Figure 5 This is a flowchart illustrating the lane departure mitigation control procedure.

[0026] Figure 6 This is a flowchart showing the steering over-control determination sub-procedure.

[0027] Figure 7 This is an explanatory diagram showing the target travel route based on lane departure mitigation control.

[0028] Figure 8 This is a timing diagram showing the deviation suppression control mode based on lateral acceleration.

[0029] Figure 9 This is an explanatory diagram showing the vehicle's trajectory when the driver operates the steering wheel during lane departure mitigation control.

[0030] Figure 10 This is an explanatory diagram illustrating lane departure mitigation control while driving on a curve.

[0031] Symbol Explanation

[0032] 1…This vehicle

[0033] 2… Steering mechanism

[0034] 3…Steering tie rod

[0035] 4… Steering wheel

[0036] 5… Steering Axle

[0037] 6…EPS device

[0038] 7…EPS motor

[0039] 11…Lane Departure Mitigation Control Device

[0040] 11a…Horizontal Position Calculation Unit

[0041] 11b… Deviation Decision Calculation Unit

[0042] 11c… Deviation Suppression Control Arithmetic Unit

[0043] 11d…Steering torque calculation unit

[0044] 12…Steering torque sensor

[0045] 13…vehicle speed sensor

[0046] 14…Yaw rate sensor

[0047] 15…Steering angle sensor

[0048] 21… camera unit

[0049] 22…Car-mounted camera

[0050] 22a…Main Camera

[0051] 22b…Secondary camera

[0052] 23…Image Processing Department

[0053] 24… Lane Recognition Department

[0054] Co… controls the start of the horizontal position.

[0055] FL, FR... left and right front wheels

[0056] Fc… Deviation from inhibition control flag

[0057] RL, RR... left and right rear wheels

[0058] T0~T5…Time elapsed

[0059] Ts…Steering torque

[0060] Tso…Over-control determination threshold

[0061] Wm…vehicle width

[0062] a…lateral acceleration

[0063] Lateral acceleration at the end of ae…

[0064] ao…initial lateral acceleration

[0065] astd… controls standard lateral acceleration

[0066] Δθ…difference

[0067] θo…Target turning angle

[0068] θst…actual steering angle Detailed Implementation

[0069] Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings. Figure 1 In this vehicle (the vehicle itself) 1, there are left and right front wheels FL and FR, and left and right rear wheels RL and RR. The left and right front wheels FL and FR are connected to the steering mechanism 2, such as the rack and pinion mechanism, via the steering tie rod 3. In addition, the steering mechanism 2 is connected to the steering shaft 5, on which the steering wheel 4 is fixedly mounted. When the driver operates the steering wheel 4, the front wheels FL and FR are steered via the steering mechanism 2.

[0070] Additionally, an EPS motor 7 for an electric power steering (EPS) device 6 is connected to the steering shaft 5 via a transmission mechanism not shown. The EPS device 6 includes the EPS motor 7 and an EPS control unit (EPS_ECU) 8.

[0071] The EPS_ECU8 controls the steering torque applied to the steering shaft 5 by the EPS motor 7. Specifically, the EPS_ECU8 sets the steering torque (steering assist torque) that assists the driver in applying steering torque to the steering wheel 4 based on the steering torque detected by the steering torque sensor 12 (described later) and the vehicle speed detected by the vehicle speed sensor 13 (described later). By applying steering assist torque to the steering shaft 5, the driver's steering wheel operation workload is reduced.

[0072] Furthermore, the EPS_ECU8 can communicate freely with the Lane Departure Prevention (LDP)_ECU11 via an in-vehicle communication network such as CAN (Controller Area Network). Each of these ECUs8 and ECU11 is composed of a known integrated circuit equipped with a CPU, RAM, ROM, non-volatile memory, and other peripheral devices. The ROM pre-stores programs executed by the CPU and / or fixed data such as tables and maps.

[0073] In lane departure suppression control, a command signal corresponding to the steering torque set by LDP_ECU11 is sent to EPS_ECU8. EPS_ECU8 then generates a predetermined steering assist torque in EPS motor 7, thereby controlling the vehicle 1 to travel inside the dividing line of the departure direction to suppress lane departure. It should be noted that, for ease of understanding, the situation where the vehicle 1 deviates from its lane will be described as "lane departure." Here, "the vehicle deviating from its lane" can mean that, when viewed vertically from above, at least a portion of the vehicle 1 is outside the lane in which the vehicle 1 is traveling. For ease of understanding, the lane in which the vehicle 1 is traveling is sometimes referred to as the "driving lane." The driving lane is the area between the left lane line and the right lane line. The left edge of the driving lane is defined by the inner edge of the left lane line. The right edge of the driving lane is defined by the inner edge of the right lane line.

[0074] In addition, although there is no diagram, in the in-vehicle communication network, apart from EPS_ECU8 and LDP_ECU11, the drive source control unit, transmission control unit, brake control unit and other unit devices that control the vehicle's driving status, such as the drive source control unit that controls the output of the drive source such as the engine and / or the electric motor for driving, are connected in a way that allows them to communicate with each other.

[0075] Furthermore, the LDP_ECU11 is connected to a vehicle behavior detection unit, which includes a steering torque sensor 12 mounted on the steering shaft 5 to detect the steering torque generated by the driver's steering wheel 4 operation, a vehicle speed sensor 13 to detect the vehicle speed, a yaw rate sensor 14 to detect the yaw rate and lateral acceleration generated by the vehicle body, and a steering angle sensor 15, which acts as a steering angle detection unit to detect the actual steering angle (actual steering angle) θst generated by the driver's steering wheel operation based on the rotation angle of the steering shaft 5. It should be noted that the steering torque detected by the steering torque sensor 12 and the vehicle speed detected by the vehicle speed sensor 13 are also sent to the lane recognition unit 24, which will be described later. In this embodiment, left turn is considered positive (+) and right turn is considered negative (-) to detect the steering torque detected by the steering torque sensor 12 and the actual steering angle θst detected by the steering angle sensor 15.

[0076] On the other hand, symbol 21 is a camera unit that serves as a driving environment recognition unit, such as Figure 2 As shown, the vehicle includes a vehicle-mounted camera 22, consisting of a main camera 22a and a secondary camera 22b forming a stereo camera system, an image processing unit 23, and a lane recognition unit 24. The two cameras 22a and 22b are positioned horizontally above, for example, the interior mirror at the front of the vehicle, spaced equally to the left and right from the center of the vehicle's width direction near the windshield. Furthermore, each camera 22a and 22b is equipped with a color imaging element such as a color CCD and / or a color CMOS sensor, and these two color imaging elements are used to capture three-dimensional color images of the driving environment ahead of the vehicle 1, including the lane in which it is traveling and the dividing lines separating the lane.

[0077] The image processing unit 23 converts a pair of analog images captured by cameras 22a and 22b into digital images with a predetermined brightness level. It generates reference image data based on the output signal of the main camera 22a and comparison image data based on the output signal of the secondary camera 22b. Then, based on the parallax between the reference image data and the comparison image data, it calculates the distance data (distance from the vehicle to the object) of the same object in the two images.

[0078] Furthermore, the lane recognition unit 24 is composed of an integrated circuit. On an imaginary road plane generated based on reference image data and comparison image data sent from the image processing unit 23, it sets left and right lane dividing lines identified by methods such as pattern matching, and calculates the distance between the inner edges of the left and right dividing lines (lane width) based on distance data. Then, it sends this data as lane recognition information to the LDP_ECU11.

[0079] like Figure 3 As shown, the LDP_ECU11 has a lateral position calculation unit 11a, a lane departure determination calculation unit 11b, a lane departure suppression control calculation unit 11c, and a steering torque calculation unit 11d, which are used to control lane departure suppression.

[0080] The lateral position calculation unit 11a calculates the lateral position from the inner edge of the left and right dividing lines to the center of the vehicle width Wm of the vehicle 1 based on the lane recognition information sent from the lane recognition unit 24. Alternatively, the lateral position can be calculated based on the center between the inner edges of the two dividing lines.

[0081] Furthermore, the lane departure determination calculation unit 11b calculates a predicted lateral movement amount based on the lateral position obtained by the lateral position calculation unit 11a, predicting the change in the lateral position of the vehicle over time. If it is predicted that the predicted lateral movement amount may lead to lane departure (between lane lines), the lane departure suppression control calculation unit 11c sets a target travel route to avoid lane departure according to a preset lane departure suppression control mode, and calculates a target steering angle based on the target travel route.

[0082] The steering torque calculation unit 11d sets the steering torque (control quantity) corresponding to the steering angle signal from the deviation suppression control calculation unit 11c and sends it to the EPS_ECU8. The EPS_ECU8 drives the EPS motor 7 based on the steering torque sent from the LDP_ECU11, thereby generating the steering assist torque as predetermined. As a result, when it is determined that... Figure 7 If there is a possibility of lane departure from the predicted travel route (the time-dependent trajectory of the predicted lateral movement) shown by the dashed line in the figure, lane departure can be avoided by making the vehicle 1 travel along the target travel route shown by the solid line in the figure.

[0083] Specifically, the lane departure determination processing performed by the aforementioned lane departure determination calculation unit 11b is in accordance with... Figure 4 The lane departure determination procedure shown is executed. It should be noted that the processing based on this procedure corresponds to the predicted lane departure determination unit of the present invention.

[0084] In this procedure, firstly, in step S1, the predicted lateral movement amount is calculated based on the vehicle speed detected by the vehicle speed sensor 13 and the steering angle detected by the steering angle sensor 15, or based on the yaw rate detected by the yaw rate sensor 14, to predict the change in the lateral position of the vehicle over time.

[0085] Next, proceed to step S2 to investigate whether the predicted lateral movement crosses the deviation from the determined lateral position. For example... Figure 7As shown, in this embodiment, the deviation determination lateral position is set from the inner edge of the dividing line to the inner edge of only 1 / 2 of the vehicle width Wm. Furthermore, the lateral position of vehicle 1 is referenced to the center of the vehicle width Wm direction relative to this deviation determination lateral position. Therefore, if the predicted lateral movement of vehicle 1 crosses the deviation determination lateral position, vehicle 1 deviates from the lane.

[0086] Then, if the predicted lateral movement amount is predicted to cross the deviation determination lateral position, proceed to step S3, set the deviation suppression control flag Fc (Fc←1), and exit the program. Alternatively, if the predicted lateral movement amount is predicted not to cross the deviation determination lateral position, branch to step S4, clear the deviation suppression control flag Fc to zero (Fc←0), and exit the program.

[0087] The value of the lane departure suppression control flag Fc is read by the lane departure suppression control calculation unit 11c. Specifically, the lane departure suppression control performed by the lane departure suppression control calculation unit 11c is based on... Figure 5 The lane departure suppression control procedure shown is executed. It should be noted that the processing based on this procedure corresponds to the lane departure suppression control unit of the present invention.

[0088] In this procedure, firstly, in step S11, the value of the departure suppression control flag Fc is investigated. Then, if Fc = 1, it is determined that the predicted lateral movement of vehicle 1 has crossed the departure determination lateral position, and the procedure proceeds to step S12. Conversely, if Fc = 0, it is determined that the predicted lateral movement is within the departure determination lateral position, i.e., it has not crossed the departure determination lateral position, and the procedure exits. As a result, when Fc = 0, if vehicle 1 is equipped with a lane keeping control (ALK) unit, the ALK unit determines the center (lane center) based on the left and right dividing lines identified by the lane recognition unit 24 of camera unit 21, and performs lane keeping control to keep vehicle 1 in the center of the lane.

[0089] In addition, when the vehicle 1 is not equipped with an ALK unit, or when the ALK unit is turned off, the EPS_ECU8 calculates the steering torque corresponding to the driver's steering wheel operation 4, and uses the steering torque to drive the EPS motor 7 to assist the driver's steering wheel operation.

[0090] Then, if step S12 is entered, it is investigated whether this is the initial procedure after determining that there is a possibility of lane departure, for example, whether this is the initial procedure after the value of the lane departure suppression control flag Fc is switched from 0 to 1.

[0091] Then, in the initial procedure after determining that there is a possibility of lane departure, proceed to step S13, set the target lateral position for each calculation cycle according to the lane departure suppression control mode, and proceed to step S14.

[0092] Here, refer to Figure 8 The lane departure suppression control mode will be briefly explained below. It should be noted that the symbol ao in the figure is the initial lateral acceleration when the lane departure determination calculation unit 11b predicts that there is a possibility of lane departure, astd is the control standard lateral acceleration for turning in a state where the lateral acceleration is constant (lateral acceleration ≠ 0), and ae is the lateral acceleration at the end of the lane departure suppression control.

[0093] Applying the control of lateral acceleration based on this deviation suppression control mode to Figure 7 The following explanation will be based on the target travel route shown. First, the control start lateral position Co, which is the distance from the lane departure determination lateral position predicted by the lane departure determination calculation unit 11b as a possibility of lane departure, is determined, and lane departure suppression control is started from this control start lateral position Co (after time T0). Then, the steering wheel is turned so that the initial lateral acceleration ao at this time is reduced to the control standard lateral acceleration astd by a preset control start abruptness (jerk). It should be noted that the initial lateral acceleration ao is obtained by multiplying the yaw rate detected by the yaw rate sensor 14 by the vehicle speed detected by the vehicle speed sensor 13. Alternatively, the lateral acceleration for the current turning angle can be predicted and set based on a vehicle model that measures the lateral acceleration when making a fixed circle turn at a certain fixed turning angle.

[0094] Then, when the control standard lateral acceleration ASTD is reached (after time T1), the vehicle turns to a fixed steering angle (after time T1 to T2). Thereafter, just before the determined lateral position is reached, the steering wheel is returned to a pre-set return angle, causing the vehicle 1 to travel along the determined lateral position for a predetermined time (approximately 8 to 12 seconds) (after time T3 to T4). Instead of immediately ending lane departure suppression control by returning the vehicle 1 to the center of the lane as in the past, by traveling along the determined lateral position for only a predetermined time as shown in time T3 to T4, it is possible to prevent further deviation, for example, while driving on a curve.

[0095] It should be noted that, in Figure 7 In this case, because the deviation suppression control is applied while driving on a straight road, the lateral acceleration 'a' becomes almost zero over time T3 to T4. Regarding this, as... Figure 10 As shown, in the deviation suppression control when driving on a curve, since the lateral position for deviation determination is set along the curve, during the elapsed time T3 to T4, as... Figure 8 As shown by the dashed line, the vehicle turns with a predetermined lateral acceleration.

[0096] Then, turn the steering wheel slightly to guide the vehicle in the opposite direction of lane departure, i.e., the return direction, until the lateral acceleration ae at the end is reached, then the lane departure suppression control ends.

[0097] Additionally, when performing the procedure a second or subsequent time after determining that there is a possibility of lane departure, jump to step S14.

[0098] If the process proceeds from step S12 or S13 to step S14, the target steering angle θo is set based on the target's lateral position. That is, in Figure 8 In the deviation suppression control mode shown, during the elapsed time T0 to T1, the target steering angle θo is set to reach the control standard lateral acceleration astd, corresponding to the steering abruptness set based on the target lateral position. Furthermore, during the elapsed time T1 to T2, a fixed target steering angle θo is set to maintain the control standard lateral acceleration astd.

[0099] Furthermore, during the elapsed time T2 to T3, a target steering angle θo is set with the deviation from the determined lateral position as the target point. During the elapsed time T3 to T4, a target steering angle θo is set for traveling along the deviation from the determined lateral position. Then, during the elapsed time T4 to T5, a target steering angle θo is set to return the vehicle 1 to the lane return direction (the direction opposite to the lane deviation direction).

[0100] After setting the target steering angle θo based on the deviation suppression control mode in step S14, the process proceeds to step S15, where steering overshoot determination processing is executed, leading to step S16. This steering overshoot determination processing follows... Figure 6 The steering overshoot determination sub-routine shown is executed. It should be noted that the processing based on this sub-routine corresponds to the steering overshoot determination unit of this invention.

[0101] In this sub-procedure, firstly, in step S21, the steering torque Ts detected by the steering torque sensor 12 is read. Next, in step S22, the steering torque Ts is compared with the overshoot determination threshold Tso. If Ts ≥ Tso, it is determined that the driver intentionally overshoots the steering wheel 4, and the process proceeds to step S23. Otherwise, if Ts < Tso, the procedure exits and proceeds to... Figure 5 Step S16. It should be noted that, taking into account sensor offset and / or sensor variations due to road surface changes, the overdrive determination threshold Tso is set to a value that can reliably determine that the driver is holding (keeping) the steering wheel 4.

[0102] If the process proceeds to step S23, the lane departure direction of vehicle 1 is investigated based on the direction of the predicted lateral movement calculated in step S1. Next, the process proceeds to step S24, investigating whether the driver turns the steering wheel 4 in the lane departure direction or in the lane return direction. The direction (sign) of the steering wheel 4 turned by the driver is investigated based on the direction generated by the steering torque Ts detected by the steering torque sensor 12.

[0103] Next, it is investigated whether the steering direction is consistent with the lane departure direction. Then, if it is determined that the direction of the predicted lateral movement is consistent with the direction of steering wheel 4 operation, it is determined that the driver intentionally turned steering wheel 4 in the direction of lane departure, and the program is directly exited and enters... Figure 5 Step S16. Therefore, the steering assist torque used to prevent lane departure is maintained unchanged. On the other hand, if the direction of the predicted lateral movement is inconsistent with the steering direction of the steering wheel 4, it is determined that the driver intentionally turns the steering wheel 4 in the lane return direction, and proceeds to step S25.

[0104] In step S25, the target steering angle θo set by the deviation suppression control calculation unit 11c is read. Next, in step S26, the actual steering angle θst, which incorporates the driver's steering wheel operation, is read by the steering angle sensor 15. Then, in step S27, the difference Δθ (Δθ = θst - θo) between the actual steering angle θst and the target steering angle θo is calculated. Based on this difference Δθ, the steering control direction relative to the target steering angle θo generated by the actual steering angle θst through the driver's steering wheel operation is investigated.

[0105] Next, proceed to step S28 to investigate whether the steering control direction of the target steering angle θo is in a deviating direction relative to the actual steering angle θst. Then, if it is determined that the target steering angle θo is in the lane return direction, i.e., the steering wheel direction, relative to the actual steering angle θst, it is determined that the steering assist torque is located on a safer side than the steering wheel operation direction intended by the driver, and the program exits directly, proceeding to... Figure 5 Step S16.

[0106] On the other hand, if it is determined that the target steering angle θo is located in the lane departure direction (i.e., the return steering direction) relative to the actual steering angle θst, a relatively large reaction force is generated on the driver's steering wheel operation, contrary to the driver's intention. Therefore, step S29 is entered to prevent this reaction force. In step S29, the target steering angle θo is set at a predetermined angle further than the actual steering angle θst towards the side opposite to the lane departure direction (the return steering direction), i.e., the steering direction. Figure 5Step S16. Thus, when the driver operates the steering wheel in the steering direction, a steering assist torque can be generated to actively assist the steering wheel operation.

[0107] If you enter Figure 5 In step S16, the deviation suppression control calculation unit 11c outputs a steering angle signal corresponding to the target steering angle θo to the steering torque calculation unit 11d. Then, the steering torque calculation unit 11d sets the steering torque (control quantity) corresponding to the steering angle signal and sends it to the EPS_ECU8. Based on this steering torque, the EPS_ECU8 drives the EPS motor 7, thereby generating the steering assist torque as predetermined.

[0108] For example, such as Figure 9 As shown, the deviation suppression control calculation unit 11c is set to make the vehicle 1 move along the deviation determination lateral position (refer to...) Figure 7 During the interval of the target steering angle θo (after time T3 to T4), the driver turns the steering wheel 4 in the lane return direction. Then, if the steering torque Ts at this time is above the over-control determination threshold Tso (Ts≥Tso) and the actual steering angle θst detected by the steering angle sensor 15 is located closer to the lane return direction than the target steering angle θo, it is determined that the vehicle 1 is under steering over-control, and the deviation suppression control calculation unit 11c guides the vehicle 1 in a safe direction.

[0109] Therefore, in this embodiment, even if the lane departure control calculation unit 11c determines that the vehicle 1 is being over-steering and is being guided by the lane departure suppression control unit 11c to return to the lane, the lane departure control is not terminated but is continued, thus particularly preventing lane departure when driving on curves.

[0110] Furthermore, the lane departure suppression control calculation unit 11c sets the target steering angle θo at a predetermined angle further towards the lane return direction (steering direction) than the actual steering angle θst. Therefore, while lane departure suppression control is continuously in operation, a more aggressive steering assist torque can be generated to assist the driver's steering wheel operation. As a result, the driver can perform smooth steering wheel operation without discomfort.

[0111] It should be noted that the lane departure suppression control based on the lane departure suppression control calculation unit 11c is executed according to the lane departure suppression control mode. Therefore, when the lane departure suppression control is in progress, if the steering torque Ts generated by the driver's steering intervention becomes less than the overtaking judgment threshold Tso (Ts < Tso), the lane departure suppression control calculation unit 11c will start the lane departure control based on the lane departure suppression control mode again.

[0112] Therefore, after the time interval T3 to T4, the deviation from the horizontal position of the judgment (refer to) is started again. Figure 7And the deviation suppression control during driving. Additionally, at this time, in Figure 4 In step S2, if it is determined that the predicted lateral movement has not crossed the deviation determination lateral position, and if the lane departure suppression control flag Fc is cleared to zero in step S4 (Fc←0), the lane departure suppression control is released.

[0113] It should be noted that the present invention is not limited to the above-described embodiments; for example, LDP_ECU11 can also be applied to autonomous driving.

Claims

1. A lane departure suppression control device, characterized in that, have: The driving environment recognition unit recognizes the driving environment in front of the vehicle and detects the left and right dividing lines of the lane in which the vehicle is traveling based on the recognized driving environment. The steering angle detection unit detects the actual steering angle based on the driver's steering wheel operation. The vehicle behavior detection department detects the behavior of the vehicle. The lane departure prediction unit predicts whether the vehicle will deviate from the lane based on the left and right dividing lines detected by the driving environment recognition unit and the vehicle's behavior detected by the vehicle behavior detection unit. A lane departure suppression control unit, which, when the lane departure prediction unit predicts that the vehicle will deviate from the lane, sets a target steering angle to suppress the vehicle's lane departure and performs lane departure suppression control; and The steering overshoot determination unit investigates whether there is steering overshoot based on the driver's steering wheel operation when the target steering angle is set by the lane departure suppression control unit. In the lane departure suppression control device, The lane departure suppression control unit If the steering overshoot determination unit detects steering overshoot and the target steering angle is located in the lane return direction (i.e., the steering wheel direction) relative to the actual steering angle detected by the steering angle detection unit, the vehicle is controlled using the target steering angle to assist the driver's steering wheel operation. If the steering overshoot determination unit detects steering overshoot and the target steering angle is located in the lane departure direction (i.e., the return direction) relative to the actual steering angle detected by the steering angle detection unit, the target steering angle is set at a predetermined angle that is further towards the lane return direction (i.e., the steering direction) than the actual steering angle to assist the driver's steering wheel operation.

2. The lane departure suppression control device according to claim 1, characterized in that, The lane departure suppression control unit continues to perform lane departure suppression control even when the steering overshoot determination unit detects steering overshoot.

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