Driving Support Devices

Abstract

To provide a drive assistance device that is able to reduce the possibility of occurrence of unintended operation of a steering wheel by a driver due to rotation of a steering wheel caused by lane deviation avoidance control.SOLUTION: A drive assistance device includes: a driving device configured to change a steering angle, which is an angle of a turning wheel of a vehicle, by applying torque to a steering shaft connected to a steering wheel provided in the vehicle; and a control unit. If a starting condition is satisfied, the control unit executes lane deviation avoidance control for controlling the driving device so as to change a steering angle in order to avoid deviation of the vehicle from a driving lane in which the vehicle is traveling. If a vehicle driver's holding position of the steering wheel does not satisfy a prescribed specific condition at a point in time that the starting condition is satisfied, the control unit executes control such that a magnitude of a steering angle speed, which is an amount of change in a steering angle per unit time, is smaller than that in a case where the holding position satisfies the specific condition at the point in time that the starting condition is satisfied.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present invention relates to a driving assistance device that executes lane departure avoidance control for changing a steering angle of a vehicle to prevent the vehicle from departing from a driving lane in which the vehicle is traveling. [Background technology]

[0002] Conventionally, driving assistance devices that execute lane departure avoidance control have been known. For example, the driving assistance device described in Patent Document 1 (hereinafter referred to as the "conventional device") executes lane departure avoidance control by applying a steering torque to a steering mechanism according to an input torque due to a steering operation by a driver. This makes it possible to reduce the steering torque when the driver intentionally drives the vehicle so as to deviate from the lane, and to increase the steering torque when the driver unintentionally drives the vehicle so as to deviate from the lane. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2010-100120 A Summary of the Invention

[0004] During execution of lane departure avoidance control, a steering torque is applied to a "steering shaft connected to the steering wheel of the vehicle" in order to change the steering angle of the vehicle. Therefore, during execution of lane departure avoidance control, the steering wheel also rotates.

[0005] Due to this steering rotation, depending on the position in which the driver holds the steering wheel, there is a possibility that the driver may perform an unintended operation on the steering wheel. For example, the weight of the driver's hands holding the steering wheel may cause the steering wheel to be turned further. Furthermore, the driver may be surprised by the rotation of the steering wheel due to the lane departure avoidance control and may perform unintended operation on the steering wheel.

[0006] The present invention has been made to address the above-mentioned problems. That is, one of the objects of the present invention is to provide a driving assistance device that can reduce the possibility of an unintended operation of the steering wheel by the driver due to the rotation of the steering wheel caused by lane departure avoidance control.

[0007] The driving assistance device of the present invention (hereinafter also referred to as the "device of the present invention") is a drive device (34) configured to change a steering angle, which is the angle of steered wheels of a vehicle (VA), by applying a torque to a steering shaft (US) connected to a steering wheel (SW) of the vehicle; a control unit (20, 30) configured to execute lane departure avoidance control for controlling the drive device to change the steering angle in order to avoid the vehicle departing from a driving lane in which the vehicle is traveling, when a predetermined start condition is satisfied; Equipped with.

[0008] The control unit When the holding position, which indicates the position of the driver's hands holding the steering wheel, does not satisfy a specific condition (step 710 "No") at the time when the start condition is satisfied, the lane departure avoidance control is executed so that the magnitude of the steering angle velocity, which is the amount of change in the steering angle per unit time, is smaller than when the holding position satisfies the specific condition (step 710 "Yes") at the time when the start condition is satisfied (MapGytgt(T), steps 660, 665, 1105, steps 1205 to 1225). It is structured as follows.

[0009] As a result, when the holding position does not satisfy the specific condition, the magnitude of the rotation speed of the steering wheel due to the lane departure avoidance control is smaller than when the holding position satisfies the specific condition, thereby reducing the possibility that the driver will turn the steering wheel further or perform an unintended operation due to the rotation of the steering wheel due to the lane departure avoidance control.

[0010] In one embodiment of the device of the present invention, The control unit is configured to extend the execution time of the lane departure avoidance control by earlier establishment of the start condition when the holding position does not satisfy the specific condition than when the holding position does not satisfy the specific condition (steps 665 and 670).

[0011] According to this aspect, when the holding position does not satisfy the specific condition, the lane departure avoidance control is started at an earlier timing than when the holding position satisfies the specific condition, thereby making the execution time of the lane departure avoidance control longer. Therefore, even if the magnitude of the steering angle speed when the holding position does not satisfy the specific condition is made smaller than when the holding position satisfies the specific condition, the lane departure avoidance control can be executed.

[0012] In one embodiment of the device of the present invention, The control unit The system is configured to determine that the start condition is met when the widthwise distance (Ds) of the vehicle in the width direction of the travel lane from a predetermined reference point (P) of the vehicle to an avoidance position (PP) set in the width direction of the travel lane matches a required distance (Dsn), which is the distance required for the lateral vehicle speed, which is the vehicle speed in the width direction of the vehicle, to become zero when a predetermined control time (Tc) has elapsed (step 650 ``Yes'').

[0013] According to this aspect, it is possible to prevent the reference point from exceeding the avoidance position while lane departure avoidance control is being executed.

[0014] In the above aspect, If the holding position does not satisfy the specific condition (step 645 "No"), the control unit is configured to determine that the start condition is met before the widthwise distance matches the required distance (step 665 "Yes").

[0015] According to this aspect, when the holding position does not satisfy the specific condition, the lane departure avoidance control is started at an earlier timing than when the holding position does not satisfy the specific condition, thereby lengthening the execution time of the lane departure avoidance control. Therefore, even if the magnitude of the steering angle speed when the holding position does not satisfy the specific condition is made smaller than when the holding position satisfies the specific condition, it is possible to reduce the possibility that the reference point will exceed the avoidance position during execution of the lane departure avoidance control, and further to increase the possibility that the lateral vehicle speed will become zero when the reference point reaches the avoidance position.

[0016] In the above aspect, When the holding position does not satisfy the specific condition (step 645 "No" shown in FIG. 6), the control unit is configured to set the avoidance position at a position a predetermined distance away in the opposite direction to the direction toward the center of the driving lane in the width direction (step 1105) and to make the control time longer than when the holding position satisfies the specific condition.

[0017] According to this aspect, when the holding position does not satisfy the specific condition, the avoidance position is set at a distant position, and the execution time of the lane departure avoidance control is extended compared to when the holding position does not satisfy the specific condition. Therefore, even if the magnitude of the steering angle speed when the holding position does not satisfy the specific condition is set smaller than when the holding position satisfies the specific condition, the possibility that the reference point will exceed the "avoidance position set at a distant position" during execution of the lane departure avoidance control can be reduced. Furthermore, the possibility that the lateral vehicle speed will become zero when the reference point reaches this avoidance position can be increased.

[0018] In one embodiment of the device of the present invention, The control unit is configured to, when the holding position does not satisfy the specific condition at the time when the condition is established, reduce the magnitude of the steering angular velocity in an initial period from the time when the condition is established until a predetermined time (Td) has elapsed, compared to the magnitude of the steering angular velocity when it is assumed that the holding position satisfies the specific condition at the time when the condition is established, and to increase the magnitude of the steering angular velocity by an amount by which the magnitude of the steering angular velocity was reduced in the initial period after the predetermined time has elapsed from the time when the condition is established (lateral acceleration map MapGytgt(T) shown in FIG. 13).

[0019] The period immediately after the start of lane departure avoidance control is the period during which the possibility of further turning and unintended operation of the steering wheel is highest. According to this aspect, when the holding position does not satisfy the specific condition, the magnitude of the rotation speed of the steering wheel due to the lane departure avoidance control is smaller in the initial period than when the holding position satisfies the specific condition. This reduces the possibility of further turning and unintended operation of the steering wheel in the initial period.

[0020] In one embodiment of the device of the present invention, The control unit In the lane departure avoidance control, the drive device is controlled so that the magnitude of the steering angular velocity does not exceed a predetermined guard value; When the holding position does not satisfy the specific condition at the time when the determination is made (step 1205 "No"), the lane departure avoidance control is executed using a guard value smaller than that when the holding position satisfies the specific condition at the time when the determination is made (step 1210) (step 1220, step 1225). It is structured as follows.

[0021] When the holding position does not satisfy the specific condition, a smaller guard value is used than when the holding position satisfies the specific condition, and the magnitude of the rotation speed of the steering wheel is reduced. This reduces the possibility of the steering wheel being turned further and unintended operation occurring when the holding position does not satisfy the specific condition.

[0022] In one embodiment of the device of the present invention, The control unit is configured to determine that the holding position satisfies the specific condition when the driver is holding the steering wheel with both hands and the positions of the driver's hands holding the steering wheel are linearly symmetrical with respect to a virtual reference line (BL) connecting the point directly above and the point directly below the steering wheel when the steering wheel is in the neutral position (step 710 ``Yes'').

[0023] Compared to when the holding position is line-symmetrical with respect to the reference line, when the driver holds the steering wheel with one hand, and when the driver holds the steering wheel with both hands but the holding position is not line-symmetrical with respect to the reference line, there is a high possibility that the steering wheel will be turned further and an unintended operation will occur. In this aspect, since it is determined that the holding position does not satisfy the specific condition in such cases, when the driver holds the steering wheel in a manner that increases the possibility of the steering wheel being turned further and an unintended operation will occur, lane departure avoidance control can be executed to reduce the magnitude of the steering angular speed.

[0024] In the above description, in order to facilitate understanding of the invention, the names and / or symbols used in the embodiments described below are enclosed in parentheses with respect to the configuration of the invention corresponding to the embodiments. However, each component of the invention is not limited to the embodiments defined by the names and / or symbols. [Brief description of the drawings]

[0025] [Figure 1] FIG. 1 is a schematic system configuration diagram of a driving assistance device according to an embodiment of the present invention. [Diagram 2] FIG. 2 is an explanatory diagram of the lane departure avoidance control. [Diagram 3] FIG. 3 is a front view of a steering wheel held to satisfy a specific condition. [Figure 4A] FIG. 4A is a front view of a steering wheel held in one hand. [Figure 4B] FIG. 4B is a front view of the steering wheel when it starts to rotate due to lane departure avoidance control. [Figure 4C] FIG. 4C is a front view of the steering wheel when further turning occurs. [Diagram 5] FIG. 5 is an explanatory diagram of an example of the operation of the lane departure avoidance control when a specific condition is not satisfied. [Figure 6] FIG. 6 is a flowchart showing a start determination routine executed by the CPU of the driving assistance ECU shown in FIG. [Figure 7] FIG. 7 is a flowchart showing a specific condition determination subroutine executed by the CPU of the driving assistance ECU shown in FIG. [Figure 8] FIG. 8 is a flowchart showing a lane departure avoidance control routine executed by the CPU of the driving assistance ECU shown in FIG. [Figure 9] FIG. 9 is a flowchart showing a termination determination routine executed by the CPU of the driving assistance ECU shown in FIG. [Figure 10] FIG. 10 is an explanatory diagram of an example of the operation of lane departure avoidance control according to the first modified example of the embodiment of the present invention. [Figure 11] FIG. 11 is a flowchart showing a start determination routine of a first modified example of the embodiment of the present invention. [Figure 12] FIG. 12 is a flowchart showing a lane departure avoidance control routine according to the second modified example of the embodiment of the present invention. [Figure 13] FIG. 13 is an explanatory diagram of an example of operation of lane departure avoidance control according to the third modified example of the embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0026] <Configuration> As shown in FIG. 1, a driving assistance device (hereinafter, referred to as "this assistance device") 10 according to an embodiment of the present invention is mounted on a vehicle VA.

[0027] The assistance device 10 includes a driving assistance ECU 20 and an electric power steering ECU 30. The driving assistance ECU 20 is referred to as a "DSECU 20," and the electric power steering ECU 30 is referred to as an "EPS ECU (Electric Power Steering ECU) 30."

[0028] These ECUs are electric control units that include a microcomputer as a main component, and are connected to each other via a controller area network (CAN) (not shown) so that they can transmit and receive information to each other. The microcomputer includes a CPU, ROM, RAM, and an interface (I / F), etc. The CPU is configured to realize various functions by executing instructions (programs, routines) stored in the ROM. Some or all of these ECUs may be integrated into one ECU. These ECUs may also be called "control units" or "controllers."

[0029] The assistance device 10 includes a camera sensor 21, an acceleration sensor 23, a steering angle sensor 24, a steering torque sensor 25, and a touch sensor 26. These are mounted on the vehicle VA. The DSECU 20 is connected to these sensors and receives detection signals from these sensors. These sensors may be connected to an ECU other than the DSECU 20. In this case, the DSECU 20 receives the detection signal of the sensor from the ECU to which the sensor is connected via the CAN.

[0030] The camera sensor 21 acquires image data by photographing the scenery in the area ahead of the vehicle VA, and transmits the image data to the DSECU 20. The DSECU 20 recognizes boundary lines based on the image data. A boundary line is a line that marks the boundary between "the lane in which the vehicle VA is currently traveling (hereinafter referred to as the "traveling lane")" and "an area other than the traveling lane." Examples of boundary lines include the left white line LL (see Figures 2 and 3) and the right white line LR (see Figures 2 and 3) on the road.

[0031] The acceleration sensor 23 detects the acceleration Gx in the longitudinal direction of the vehicle VA (hereinafter referred to as "longitudinal acceleration") and the acceleration Gy in the width direction of the vehicle VA (hereinafter referred to as "lateral acceleration"), and generates detection signals representing the longitudinal acceleration Gx and the lateral acceleration Gy.

[0032] The steering angle sensor 24 detects a steering angle θ, which is a rotation angle of the steering wheel SW of the vehicle VA with respect to a neutral position, and generates a detection signal indicative of the steering angle θ. The steering torque sensor 25 is provided on a steering shaft US connected to the steering wheel SW. The steering torque sensor 25 detects the steering torque applied to the steering shaft US and generates a detection signal indicative of the steering torque. The touch sensor 26 detects the position of the driver's hand touching the steering wheel SW, and generates a detection signal representing the position.

[0033] The EPS ECU 30 is a controller for a well-known electric power steering system. The EPS ECU 30 is connected to a motor driver 32.

[0034] The motor driver 32 is connected to a steering motor 34. The steering motor 34 may be referred to as a "drive device." The steering motor 34 is incorporated into a "steering mechanism including a steering wheel SW, a steering shaft US, and a steering gear mechanism (not shown)." The steering motor 34 is an electric motor (electric actuator) that applies torque (force) to the steering shaft US using power supplied from the motor driver 32. This torque is used as a steering assist torque (steering assist force). This torque makes it possible to steer the left and right steered wheels of the vehicle VA. In other words, the steering motor 34 can change the steering angle (also referred to as the "steering angle") of the vehicle SV.

[0035] When lane departure avoidance control, which will be described later, is not being executed, the EPS ECU 30 acquires the steering torque Tra detected by the steering torque sensor 15 as the steering torque input by the driver to the steering wheel SW (hereinafter also referred to as "driver torque TqDr"). The EPS ECU 30 assists the driver in operating the steering wheel SW by causing the steering motor 34 to apply the driver torque TqDr to the steering shaft US.

[0036] Furthermore, when lane departure avoidance control, which will be described later, is being executed, the EPS ECU 30 receives a steering command including a target lateral acceleration Gytgt acquired by the lane departure avoidance control from the DSECU 20. The EPS ECU 30 acquires a differential lateral acceleration ΔGy by subtracting the target lateral acceleration Gytgt from the current lateral acceleration Gy, and changes the steering angle by applying a torque according to the differential lateral acceleration ΔGt to the steering shaft US. The EPS ECU 30 increases the torque as the absolute value (|ΔGy|) of the differential lateral acceleration ΔGy increases, and the magnitude of the rotational speed of the steering wheel SW (i.e., the amount of change in steering angle per unit time) increases. The absolute value (|ΔGy|) of this differential lateral acceleration ΔGy increases as the gradient of the target lateral acceleration Gytgt in a lateral acceleration map MapGytgt(T) described later increases.

[0037] The display 40 displays a warning message during execution of the lane departure avoidance control and the operation status of the lane departure avoidance control. The display 40 may be a head-up display or a multi-function display. The speaker 50 issues a buzzer sound while the lane departure avoidance control is being executed.

[0038] <Lane Departure Avoidance Control> The lane departure avoidance control will be described with reference to FIG. The DSECU 20 acquires image data from the camera sensor 21 at every predetermined time interval, and recognizes the boundaries (e.g., the left white line LL and the right white line LR) of the lane in which the vehicle VA is currently traveling. The DSECU 20 acquires an avoidance position (avoidance line) PP by virtually moving the boundary line (hereinafter referred to as the "target boundary line") closest to the vehicle VA by a predetermined distance Dd. Lane departure avoidance control is executed so that the reference point P of the vehicle VA does not protrude outside the avoidance position PP. The reference point P is the center position between the left and right front wheels of the vehicle VA on their axles.

[0039] The DSECU 20 acquires the distance between the avoidance position PP and the current reference point P (hereinafter referred to as the "side distance Ds"). The side distance Ds may also be referred to as the "width direction distance." The DSECU 20 acquires the current lateral vehicle speed Vsy, which is the vehicle speed Vs in the vehicle width direction, by integrating the current lateral acceleration Gy over time.

[0040] Based on the current lateral vehicle speed Vsy, the DSECU 20 acquires the lateral acceleration Gy (hereinafter referred to as the "required lateral acceleration Gyn") required for the lateral vehicle speed Vsy to become zero when a predetermined control time Tc has elapsed from the current time. Then, under the assumption that the vehicle VA moves in the longitudinal direction while maintaining the "longitudinal vehicle speed Vsx, which is the current longitudinal vehicle speed Vs," and moves in the lateral direction at the required lateral acceleration Gyn, the DSECU 20 acquires as the required side distance Dsn the distance that the vehicle VA moves in the lateral direction of the travel lane during the period from the current time until the control time Tc has elapsed. In other words, the required side distance Dsn can also be expressed as the side distance Ds required for the lateral vehicle speed Vsy to become zero when a predetermined control time Tc has elapsed from the current time.

[0041] When the current side distance Ds is equal to or less than the required side distance Dsn, the DSECU20 determines that a predetermined start condition is satisfied and starts lane departure avoidance control. In the example shown in Fig. 2, at time t0, the side distance Ds is greater than the required side distance Dsn, so the start condition is not satisfied. At time t1, the side distance Ds becomes equal to or less than the required side distance Dsn, so the start condition is satisfied and lane departure avoidance control is started.

[0042] In the lane departure avoidance control, the DSECU 20 transmits a steering command including a target lateral acceleration Gytgt to the EPS ECU 30 every time a predetermined time elapses.

[0043] When starting lane departure avoidance control, the DSECU 20 generates a lateral acceleration map MapGytgt(T) (see the graph shown at the bottom of FIG. 2) that specifies the relationship between the elapsed time from the start of the lane departure avoidance control and the target lateral acceleration Gytgt. The DSECU 20 acquires the target lateral acceleration Gytgt according to the elapsed time by referring to the lateral acceleration map MapGytgt(T). Note that the target lateral acceleration Gytgt and the lateral acceleration Gy have positive values ​​for the rightward acceleration of the vehicle VA and negative values ​​for the leftward acceleration. In the example shown in FIG. 2, the rightward vehicle speed Vsy of the vehicle VA at the start time (time t1) is set to zero, so the target lateral acceleration Gytgt becomes the leftward acceleration, i.e., a negative value.

[0044] In the lateral acceleration MapGytgt(T) shown in Fig. 2, the target lateral acceleration Gytgt is decreased in the period from time t1 to time t2 so that the target lateral acceleration Gytgt becomes the predetermined lateral acceleration Ga (Ga < 0) at time t2, which is half (Tc / 2) of the control time Tc after the elapsed time. Furthermore, in the lateral acceleration MapGytgt(T) shown in Fig. 2, the lateral acceleration Gy is maintained at the predetermined lateral acceleration Ga in the period from time t2 to time t3.

[0045] DSECU20 calculates the lateral acceleration Ga so that the value (integral value) obtained by integrating the target lateral acceleration Gytght over the period from time t1 to time t3 (i.e., the area of ​​the filled-in portion in the graph shown in Figure 2) matches the "value obtained by multiplying the control time Tc by the required lateral acceleration Gyn."

[0046] At time t3, the vehicle VA reaches the avoidance position PP and the lateral vehicle speed Vsy becomes zero. In the lane departure avoidance control after time t3, the DSECU 20 transmits a steering command including a target lateral acceleration Gytgt for the vehicle VA to travel toward the center in the width direction of the traveling lane. Then, after time t3, the DSECU 20 ends the lane departure avoidance control when an end side distance Des, which is the distance between a predetermined end position and the reference point P, becomes equal to or smaller than the threshold distance Dth. The end position is obtained by virtually moving the boundary line (target boundary line) closer to the vehicle VA toward the center of the traveling lane by the predetermined end distance De.

[0047] (Overview of operation) When the holding position, which is the position of the driver's hands holding the steering wheel SW, does not satisfy a specific condition, the DSECU 20 executes lane departure avoidance control so as to reduce the amount of change per unit time of the target lateral acceleration Gytgt compared to when the holding position satisfies the specific condition. This reduces the amount of change per unit time of the steering angle (i.e., the magnitude of the rotation speed of the steering wheel SW), thereby reducing the possibility of the driver turning the steering wheel SW further and performing unintended operation during lane departure avoidance control.

[0048] The above specific conditions will be described with reference to FIG. When the positions of both hands of the driver holding the steering wheel SW are symmetrical with respect to a reference line BL of the steering wheel SW, the DSECU20 judges that the holding positions satisfy a specific condition (i.e., judges that the specific condition is established). Note that the reference line BL is an imaginary line connecting a point Pu directly above the steering wheel SW and a point Pb directly below the steering wheel SW when the steering wheel SW is in the neutral position. In the example shown in FIG. 3, the driver holds the steering wheel SW at a so-called "9:15" position, and this holding position is line-symmetrical with respect to the reference line BL, satisfying the specific condition.

[0049] When the driver holds the upper part of the steering wheel SW with one hand as shown in Fig. 4A, the above specific condition is not satisfied. When lane departure avoidance control is executed under such a situation, the steering wheel SW rotates as shown in Fig. 4B. At this time, the steering wheel SW may be turned further due to the centrifugal force generated in the "hand holding the steering wheel SW" by the rotation of the steering wheel SW.

[0050] In this embodiment, when the specific condition is not satisfied, the change in the steering angle is made smaller than when the specific condition is satisfied, so that the rotation speed of the steering wheel SW is reduced. This makes it possible to reduce the centrifugal force and reduce the possibility of the steering wheel SW being turned further. Furthermore, according to this embodiment, it is possible to reduce the possibility that the driver will be surprised by the rotation of the steering wheel SW, and therefore to reduce the possibility that the driver will perform an unintended operation on the steering wheel.

[0051] (Example of operation) Normal lane departure avoidance control (i.e., when the above-mentioned specific condition is satisfied) has been described with reference to Fig. 2. Lane departure avoidance control when the above-mentioned specific condition is not satisfied will be described with reference to Fig. 5. If the specific condition is not satisfied, the DSECU20 determines that the start condition is satisfied when the side distance Ds is equal to or less than the "distance Dsn' obtained by adding a predetermined distance Dp1 to the necessary side distance Dsn," and starts lane departure avoidance control. In the example shown in FIG. 5, it is assumed that the specific condition is not satisfied and the side distance Ds is equal to or less than the distance Dsn' at time t0. Based on this assumption, the start condition is satisfied at time t0, and lane departure avoidance control is started.

[0052] At this time point t0, the DSECU 20 generates a lateral acceleration map MapGytgt(T). The required acceleration Gyn' required until the vehicle speed Vsy (Vsy0) in the vehicle width direction at time t0 becomes zero when the required time Tn has elapsed from time t0 can be expressed using the required time Tn (see Equation 1). Gyn'=-Vsy0 / Tn...Formula 1 DSECU20 calculates the time (required time Tn) required for the "distance that vehicle VA moves in the width direction of the lane" to match distance Dsn', under the assumption that vehicle VA moves in the forward / backward direction while maintaining forward / backward vehicle speed Vsx0 at time t0 and moves in the width direction at required acceleration Gyn'. This necessary time Tn is longer than the control time Tc.

[0053] Then, the DSECU 20 calculates the lateral acceleration Ga' so that the integral value (area of ​​the blackened portion in the graph shown in FIG. 5) obtained by integrating the target lateral acceleration Gytgt corresponding to the elapsed time over the "period from the start point until the required time Tn has elapsed" matches the "product of the required lateral acceleration Gyn and the control time Tc." The DSECU 20 generates a lateral acceleration map MapGytgt(T) (see the graph in FIG. 5) based on this lateral acceleration Ga'.

[0054] As can be seen from the graph of Fig. 5, the execution time (Tn) of the lane departure avoidance control when the specific condition is not satisfied is longer than the execution time (Tc) of the lane departure avoidance control when the specific condition is satisfied. The magnitude of the gradient gr of the target lateral acceleration Gytgt from time t0 to time t2 in the lane departure avoidance control when the specific condition is not satisfied is smaller than the magnitude of the gradient gr from time t1 to time t2 in the lane departure avoidance control when the specific condition is satisfied. Therefore, the magnitude of the rotation speed of the steering wheel SW by the lane departure avoidance control when the specific condition is not satisfied (i.e., the magnitude of the steering angular velocity which is the amount of change in the steering angle of the steered wheels per unit time) can be made smaller than the magnitude of the rotation speed of the steering wheel SW (the magnitude of the steering angular velocity) when the specific condition is satisfied.

[0055] (Specific operation) <Start Judgment Routine> The CPU of the DSECU 20 (hereinafter, when written as "CPU", it refers to the CPU of the DSECU 20 unless otherwise specified) executes a start determination routine shown by the flowchart in FIG. 6 every time a predetermined time has elapsed.

[0056] Therefore, at a predetermined timing, the CPU starts the process from step 600 shown in Fig. 6, and proceeds to step 605. In step 605, the CPU determines whether or not the value of the execution flag Xexe is "0".

[0057] The value of the execution flag Xexe is set to "1" when lane departure avoidance control starts, and is set to "0" when lane departure avoidance control ends. The value of the execution flag Xexe is also set to "0" in the initial routine. The initial routine is a routine executed by the CPU when the ignition key switch (not shown) of the vehicle VA is changed from the OFF position to the ON position.

[0058] If the value of the execution flag Xexe is "0", the CPU determines "Yes" in step 605 and executes steps 615 to 645 in order.

[0059] Step 615: The CPU acquires image data from the camera sensor 21 and recognizes the boundary line based on the image data. Step 620: The CPU obtains the side distance Ds between the reference point P and the avoidance position PP. Step 625: The CPU determines the longitudinal acceleration Gx of the vehicle VA based on the detection signal from the acceleration sensor 23, and obtains the longitudinal vehicle speed Vsx, which is the vehicle speed in the longitudinal direction of the vehicle VA, by integrating the longitudinal acceleration Gx over time. Furthermore, the CPU determines the lateral acceleration Gy of the vehicle VA based on the detection signal from the acceleration sensor 23, and obtains the lateral vehicle speed Vsy by integrating the lateral acceleration Gy over time.

[0060] Step 630: The CPU obtains the required lateral acceleration Gyn based on the lateral vehicle speed Vsy and the control time Tc. Step 635: The CPU acquires the required side distance Dsn, which is the distance that the vehicle VA moves in the width direction of the lane during the period from the current time until the control time Tc has elapsed, under the assumption that the vehicle VA moves in the fore-and-aft direction while maintaining the fore-and-aft vehicle speed Vsx and moves in the width direction of the vehicle at the required lateral acceleration Gyn.

[0061] Step 640: The CPU executes a specific condition determination subroutine. In practice, when the CPU proceeds to step 640, it executes a subroutine shown in the flowchart of FIG. 7. In this subroutine, if the holding position satisfies the specific condition, the CPU sets the value of the specific flag Xsp to "0", and if the holding position does not satisfy the specific condition, the CPU sets the value of the specific flag Xsp to "1". The value of the specific flag Xsp is set to "1" in the initial routine.

[0062] Step 645: The CPU determines whether the value of the specific flag Xsp is “0” or not. If the value of the specific flag Xsp is “0”, the CPU determines “Yes” in step 645 and proceeds to step 650 .

[0063] In step 650, the CPU determines whether the side distance Ds is less than or equal to the required side distance Dsn. If the side distance Ds is greater than the required side distance Dsn, the CPU makes a "No" determination in step 650, proceeds to step 695, and temporarily ends this routine. On the other hand, if the side distance Ds is equal to or less than the required side distance Dsn, the CPU determines "Yes" in step 650 and executes steps 655 and 660 in this order.

[0064] Step 655: The CPU sets the value of the execution flag to “1” and sets the value of the execution timer Texe to “0.” The execution timer Texe is a timer for counting the elapsed time from the start of the lane departure avoidance control.

[0065] Step 660: The CPU generates a lateral acceleration map MapGytgt(T). Thereafter, the CPU proceeds to step 695 and ends this routine.

[0066] On the other hand, if the value of the specific flag Xsp is “1” when the CPU proceeds to step 645 , the CPU determines “No” in step 645 and proceeds to step 665 .

[0067] In step 665, the CPU determines whether the side distance Ds is less than or equal to the distance Dsn'. If the side distance Ds is greater than the distance Dsn', the CPU makes a "No" determination in step 665, proceeds to step 695, and temporarily ends this routine.

[0068] On the other hand, if the side distance Ds is equal to or less than the distance Dsn', the CPU determines "Yes" in step 665 and proceeds to step 670. In step 670, the CPU obtains the required acceleration Gyn' and the required time Tn. Thereafter, the CPU proceeds to step 655 to generate a lateral acceleration map MapGytgt(T), and proceeds to step 695 to temporarily end this routine.

[0069] If the value of the execution flag Xexe is "1" when the CPU proceeds to step 605, the CPU determines "No" in step 605, proceeds to step 695, and temporarily ends this routine.

[0070] <Specific condition judgment subroutine> When the CPU proceeds to step 640 shown in FIG. 6, it starts the process from step 700 shown in FIG.

[0071] Step 705: The CPU, based on the detection signal from the touch sensor 26, identifies the position of the driver's hands holding the steering wheel SW (holding position). Step 710: The CPU determines whether the holding location satisfies a specific condition.

[0072] If the holding position satisfies the specific condition, the CPU determines "Yes" in step 710 and proceeds to step 715. In step 715, the CPU sets the value of the specific flag Xsp to "0." After that, the CPU proceeds to step 795 to temporarily end this routine, and proceeds to step 645 shown in FIG. 6.

[0073] On the other hand, if the holding position does not satisfy the specific condition, the CPU determines "No" in step 710 and proceeds to step 720. In step 720, the CPU sets the value of the specific flag Xsp to "1." After that, the CPU proceeds to step 795 to temporarily end this routine, and proceeds to step 645 shown in FIG. 6.

[0074] <Lane Departure Avoidance Control Routine> The CPU executes a lane departure avoidance control routine shown in the flowchart of FIG. 8 every time a predetermined time elapses.

[0075] Therefore, at a predetermined timing, the CPU starts the process from step 800 shown in Fig. 8, and proceeds to step 805. In step 805, the CPU determines whether the value of the execution flag Xexe is "1" or not.

[0076] If the value of the execution flag Xexe is "0", the CPU makes a "No" determination in step 805, proceeds to step 895, and temporarily ends this routine.

[0077] On the other hand, if the value of the execution flag Xexe is "1", the CPU determines "Yes" in step 805 and executes steps 810 and 815 in this order.

[0078] Step 810: The CPU adds "1" to the execution timer Texe. Step 815: The CPU determines whether the value of the specific flag Xsp is “0” or not.

[0079] When the value of the specific flag Xsp is "0", the CPU determines "Yes" in step 815 and proceeds to step 820. In step 820, the CPU determines whether the value of the execution timer Texe is equal to or less than the first time threshold T1th. The first time threshold T1th is set to a value such that when the execution timer Texe reaches the first time threshold T1th, the elapsed time from the start of the lane departure avoidance control becomes the control time Tc.

[0080] If the value of the execution timer Texe is equal to or less than the first time threshold T1th, the CPU determines "Yes" in step 820 and executes steps 825 and 830 in this order. Step 825: The CPU obtains the target lateral acceleration Gytgt by applying the value of the execution timer Texe to the lateral acceleration map MapGytgt(T). Step 830: The CPU determines whether the absolute value (|ΔGy|) of the differential lateral acceleration ΔGy is equal to or smaller than a predetermined guard value grd. The differential lateral acceleration ΔGy is obtained by subtracting the target lateral acceleration Gytgt from the current lateral acceleration Gy.

[0081] If the absolute value (|ΔGy|) is equal to or less than the guard value grd, the CPU determines "Yes" in step 830 and proceeds to step 835. In step 835, the CPU transmits a steering command including the target lateral acceleration Gytgt to the EPS ECU 30. After that, the CPU proceeds to step 895 and temporarily ends this routine.

[0082] On the other hand, if the absolute value (|ΔGy|) is greater than the guard value grd, the CPU determines "No" in step 830 and proceeds to step 840. In step 840, the CPU sets the target lateral acceleration Gytgt so that the absolute value (|ΔGy|) is equal to or smaller than the guard value grd. When the lateral acceleration difference ΔGy is a positive value, the CPU sets the target lateral acceleration Gytgt to a value obtained by subtracting the guard value grd from the lateral acceleration Gy. When the lateral acceleration difference ΔGy is a negative value, the CPU sets the target lateral acceleration Gytgt to a value obtained by adding the lateral acceleration Gy and the guard value grd. Thereafter, the CPU transmits a steering command to the EPS ECU 30 in step 835, and proceeds to step 895 to temporarily end this routine.

[0083] When the CPU proceeds to step 820, if the value of the execution timer Texe is greater than the first time threshold T1th, the CPU determines "No" in step 820 and executes steps 845 and 850 in this order.

[0084] Step 845: The CPU recognizes the boundary line based on the image data from the camera sensor 21. Step 850: The CPU identifies the driving lane based on the boundary line, and obtains a target lateral acceleration Gytgt for driving the vehicle VA toward the center of the driving lane in the width direction. The CPU then proceeds to step 830.

[0085] If the value of the specific flag Xsp is “1” when the CPU proceeds to step 815, the CPU determines “No” in step 815 and proceeds to step 855. In step 855, the CPU determines whether the value of the execution timer Texe is equal to or less than the second time threshold T2th. The second time threshold T2th is set to a value such that when the execution timer Texe reaches the second time threshold T2th, the elapsed time from the start of the lane departure avoidance control becomes the required time Tn.

[0086] When the value of the execution timer Texe is equal to or less than the second time threshold T2th, the CPU determines “Yes” in step 855, proceeds to step 825, and acquires the target lateral acceleration Gytgt corresponding to the value of the execution timer Texe.

[0087] On the other hand, if the value of the execution timer Texe is greater than the second time threshold T2th, the CPU determines “No” in step 855 and proceeds to step 845.

[0088] <End Judgment Routine> The CPU executes an end determination routine shown in the flowchart of FIG. 9 every time a predetermined time period elapses.

[0089] Therefore, at a predetermined timing, the CPU starts the process from step 900 shown in Fig. 9, and proceeds to step 905. In step 905, the CPU determines whether the value of the execution flag Xexe is "1" or not.

[0090] If the value of the execution flag Xexe is "0", the CPU determines "No" in step 905, proceeds to step 995, and temporarily ends this routine. On the other hand, if the value of the execution flag Xexe is "1", the CPU determines "Yes" in step 905 and proceeds to step 910. In step 910, the CPU determines whether the value of the specific flag Xsp is "0" or not.

[0091] When the value of the specific flag Xsp is "0", the CPU determines "Yes" in step 910 and proceeds to step 915. In step 915, the CPU determines whether the value of the execution timer Texe is greater than the first time threshold T1th.

[0092] If the value of the execution timer Texe is equal to or less than the first time threshold T1th, the CPU determines "No" in step 915, proceeds to step 995, and temporarily ends this routine. On the other hand, if the value of the execution timer Texe is greater than the first time threshold T1th, the CPU determines "Yes" in step 915 and executes steps 920 to 930 in order.

[0093] Step 920: The CPU recognizes the boundary line based on the image data from the camera sensor 21. Step 925: The CPU determines the end side distance Des based on the boundary line. Step 930: The CPU determines whether the end side distance Des is less than or equal to the threshold distance Dth.

[0094] If the end side distance Des is greater than the threshold distance Dth, the CPU makes a "No" determination in step 930, proceeds to step 995, and temporarily ends this routine. On the other hand, if the end side distance Des is equal to or less than the threshold distance Dth, the CPU determines "Yes" in step 930 and executes steps 935 and 940 in this order. Step 935: The CPU sets the values ​​of the execution flag Xexe and the execution timer Texe to “0”. Step 940: The CPU erases the lateral acceleration map MapGytgt(T). Thereafter, the CPU proceeds to step 995 and ends this routine.

[0095] When the specific condition is not satisfied, the support device 10 starts the lane departure avoidance control at an earlier timing than when the specific condition is satisfied, thereby lengthening the execution time of the lane departure avoidance control. This makes it possible to make the change amount (slope) per unit time of the target lateral acceleration Gytgt smaller when the specific condition is not satisfied than when the specific condition is satisfied. Therefore, it is possible to make the magnitude of the rotation speed (magnitude of the steering angle speed) of the steering wheel SW smaller when the specific condition is not satisfied than when the specific condition is satisfied. Therefore, it is possible to reduce the possibility of the steering wheel SW being turned further, and also to reduce the possibility of the driver performing unintended operation of the steering wheel.

[0096] The present invention is not limited to the above-described embodiment, and various modifications can be adopted within the scope of the present invention.

[0097] (First Modification) The present modified example will be outlined with reference to FIG. The DSECU 20 starts lane departure avoidance control when the side distance Ds becomes equal to or less than the required side distance Dsn (see time point t1). In this case, if the specific condition is not satisfied, the DSECU 20 virtually moves the avoidance position PP by a predetermined distance Dp2 in the direction opposite to the direction toward the center of the width direction of the traveling lane (downward on the paper surface) to obtain a new avoidance position PP'.

[0098] The DSECU 20 calculates the necessary time Tn in the same manner as described in the operation example of the above embodiment. This necessary time Tn is longer than the control time Tc. Next, the DSECU 20 calculates the lateral acceleration Ga' in the same manner as described in the operation example of the above embodiment, and generates a lateral acceleration map MapGytgt(T) (see the graph in FIG. 10) based on this lateral acceleration Ga'. In the lateral acceleration map MapGytgt(T) shown in FIG. 10, the target acceleration Gytgt decreases to the lateral acceleration Ga' during the period from the start time t1 until a predetermined time (Tn-Tc / 2) has elapsed, and the target acceleration Gytgt is maintained at the lateral acceleration Ga' during the period from the time when the predetermined time (Tn-Tc / 2) has elapsed until time t4.

[0099] In lane departure avoidance control when the specific condition is not satisfied, at time t4 when the necessary time Tn has elapsed from the start time t1, the reference point P of the vehicle VA reaches the avoidance position PP' and the lateral vehicle speed Vsy becomes zero.

[0100] According to this modification, when the specific condition is not satisfied, the execution time (necessary time Tn) of the lane departure avoidance control is longer than when the specific condition is satisfied by using the avoidance position PP' instead of the avoidance position PP. This makes it possible to make the magnitude of the rotation speed (magnitude of the steering angular velocity) of the steering wheel SW by the lane departure avoidance control when the specific condition is not satisfied smaller than the magnitude of the rotation speed (magnitude of the steering angular velocity) of the steering wheel SW when the specific condition is satisfied.

[0101] The CPU of the DSECU 20 of this modification executes the start determination routine shown in Fig. 11 every time a predetermined time elapses instead of the start determination routine shown in Fig. 6, and executes the routines shown in Fig. 7 to Fig. 9 every time a predetermined time elapses. In Fig. 11, steps that perform the same processes as the steps shown in Fig. 6 are given the same reference numerals as those used in Fig. 6, and descriptions thereof will be omitted.

[0102] At a predetermined timing, the CPU starts the process from step 1100 shown in FIG. 11 and proceeds to step 605 shown in FIG. 11. When the value of the execution flag Xexe is "0", the CPU judges "Yes" at step 605 shown in FIG. 11, sequentially executes steps 615 to 635 shown in FIG. 11, and proceeds to step 650 shown in FIG. 11. When the side distance Ds is greater than the required side distance Dsn, the CPU judges "No" at step 650 shown in FIG. 11, proceeds to step 1195, and temporarily ends this routine. When the side distance Ds is equal to or less than the required side distance Dsn, the CPU judges "Yes" at step 650 shown in FIG. 11, and sequentially executes steps 640 and 645 shown in FIG. 11.

[0103] If the value of the specific flag Xsp is "0", the CPU judges "Yes" at step 645 shown in FIG. 11, executes steps 655 and 660 shown in FIG. 11 in sequence, and proceeds to step 1195 to temporarily end this routine.

[0104] If the value of the specific flag Xsp is "1", the CPU determines "No" in step 645 shown in Fig. 11, and proceeds to step 1105. In step 1105, the CPU acquires the avoidance position PP', and proceeds to step 670 shown in Fig. 11 to acquire the required time Tn. Thereafter, the CPU executes steps 655 and 660 shown in Fig. 11 in order, and proceeds to step 1195 to temporarily end this routine.

[0105] (Second Modification) When the specific condition is not satisfied at the start of the lane departure avoidance control, the DSECU 20 according to this modification uses a second guard value grd2 that is smaller than the first guard value grd1 used in the lane departure avoidance control when the specific condition is satisfied. As a result, in the lane departure avoidance control when the specific condition is not satisfied, the absolute value of the differential lateral acceleration ΔGy (|ΔGy|) does not become larger than the second guard value grd2. Therefore, the magnitude of the rotation speed (magnitude of the steering angular velocity) of the steering wheel SW in the lane departure avoidance control when the specific condition is not satisfied can be made smaller than the magnitude of the rotation speed (magnitude of the steering angular velocity) of the steering wheel SW in the lane departure avoidance control when the specific condition is satisfied.

[0106] The CPU of the DSECU 20 of this modified example executes "a start determination routine in which steps 645, 1105, and 670 are deleted from the start determination routine shown in FIG. 11" every time a predetermined time has elapsed. Furthermore, the CPU executes a lane departure avoidance control routine shown in Fig. 12 every time a predetermined time elapses. In Fig. 12, steps that perform the same processes as the steps shown in Fig. 8 are given the same reference numerals as those used in Fig. 8, and the explanation thereof will be omitted. The CPU executes the routines shown in FIGS. 7 and 9 every time a predetermined time elapses.

[0107] At a predetermined timing, the CPU starts the process from step 1200 shown in Fig. 12 and proceeds to step 805 shown in Fig. 12. If the value of the execution flag Xexe is "0", the CPU judges "No" in step 805 shown in Fig. 12, proceeds to step 1295, and temporarily ends this routine.

[0108] If the value of the execution flag Xexe is "1", the CPU determines "Yes" in step 805 shown in Fig. 12 and executes steps 810 and 815 shown in Fig. 12. If the value of the specific flag Xsp is "0", the CPU determines "Yes" in step 815 shown in Fig. 12 and proceeds to step 820 shown in Fig. 12.

[0109] When the value of the execution timer Texe is equal to or less than the first time threshold T1th, the CPU judges “Yes” in step 820 shown in FIG.

[0110] In step 1205, the CPU determines whether the value of the specific flag Xsp is "0" or not. If the value of the specific flag Xsp is "0", the CPU determines "Yes" in step 1205 and proceeds to step 1210. In step 1210, the CPU determines whether the absolute value of the differential lateral acceleration ΔGy (|ΔGy|) is equal to or smaller than a predetermined first guard value grd1.

[0111] If the absolute value (|ΔGy|) is equal to or smaller than the first guard value grd1, the CPU judges "Yes" in step 1210, and proceeds to step 835 shown in Fig. 12 to transmit a steering command. After that, the CPU proceeds to step 1295 to temporarily end this routine.

[0112] On the other hand, if the absolute value (|ΔGy|) is greater than the first guard value grd1, the CPU determines "No" in step 1210 and proceeds to step 1215. In step 1215, the CPU sets the target lateral acceleration Gytgt so that the absolute value (|ΔGy|) is equal to or less than the first guard value grd1, and proceeds to step 835 shown in Fig. 12. The details of setting the target lateral acceleration Gytgt are similar to those in step 840 shown in Fig. 8, and therefore will not be described here.

[0113] If the value of the specific flag Xsp is "1" when the CPU proceeds to step 1205, the CPU determines "No" in step 1205 and proceeds to step 1220. In step 1220, the CPU determines whether the absolute value (|ΔGy|) is equal to or smaller than a predetermined second guard value grd2. Note that the second guard value grd2 is preset to a value smaller than the first guard value grd1.

[0114] When the absolute value (|ΔGy|) is less than or equal to the second guard value grd2, the CPU determines "Yes" in step 1220 and proceeds to step 835 shown in FIG. 12. On the other hand, when the absolute value (|ΔGy|) is greater than the second guard value grd2, the CPU determines "No" in step 1220 and proceeds to step 1225. In step 1225, the CPU sets the target lateral acceleration Gytgt so that the absolute value (|ΔGy|) is less than or equal to the second guard value grd2, and proceeds to step 835 shown in FIG. 12.

[0115] As understood from the above, in the lane departure avoidance control when the specific condition is not satisfied, a second guard value grd2 smaller than the first guard value grd1 is used. Thereby, it is possible to prevent the magnitude of the rotational speed of the steering wheel SW (the magnitude of the steering angular velocity) from becoming larger than the value corresponding to the second guard value grd2. Therefore, the magnitude of the rotational speed of the steering wheel SW (the magnitude of the steering angular velocity) in the lane departure avoidance control when the specific condition is not satisfied can be made smaller than the magnitude of the rotational speed of the steering wheel SW (the magnitude of the steering angular velocity) in the lane departure avoidance control when the specific condition is satisfied.

[0116] (Third Modification Example) The third modification example will be described with reference to FIG. 13. When the specific condition is not satisfied at the start point (time point t1) of the lane departure avoidance control, the DSECU20 according to this modification example makes the magnitude of the slope of the target lateral acceleration Gytgt smaller than "the magnitude of the slope of the target lateral acceleration Gytgt indicated by the dotted line in FIG. 13 assuming that the specific condition is satisfied at the start point (time point t1)" in the initial period until a predetermined time Td (<Tc / 2) elapses from the start point. Thereby, in the initial period, the magnitude of the rotational speed of the steering wheel SW (the magnitude of the steering angular velocity) in the lane departure avoidance control when the specific condition is not satisfied can be made smaller than when the specific condition is satisfied.

[0117] The DSECU20 determines a predetermined lateral acceleration Ga' from time t2 onward so that the "integral value (area of ​​the filled-in portion in the graph shown in FIG. 13) obtained by integrating the target lateral acceleration Gytgt over the control time Tc when the specific condition is not satisfied" matches the "value (integral value) obtained by integrating the target lateral acceleration Gytgt over the control time Tc when it is assumed that the specific condition is satisfied." The magnitude of the lateral acceleration Ga' increases according to the amount by which the gradient of the target lateral acceleration Gytgt is reduced during the initial period, and the magnitude of the lateral acceleration Ga' naturally becomes greater than the lateral acceleration Ga when it is assumed that the specific condition is satisfied.

[0118] When the lane departure avoidance control starts, the steering wheel SW starts to rotate, so there is a high possibility that the lane departure avoidance control starts and the unintended operation occurs. According to this modification, the magnitude of the gradient of the target lateral acceleration Gytgt in the initial period when the specific condition is not satisfied is smaller than the magnitude of the gradient of the target lateral acceleration Gytgt when it is assumed that the specific condition is satisfied. This makes it possible to make the magnitude of the rotation speed of the steering wheel SW in the initial period when the specific condition is not satisfied smaller than the magnitude of the rotation speed of the steering wheel SW when the specific condition is satisfied.

[0119] As described above, the lateral acceleration Ga' is calculated so that the integral value when the specific condition is not satisfied coincides with the integral value when the specific condition is assumed to be satisfied. Therefore, the lateral vehicle speed Vsy becomes zero reliably at time t3 when the control time Tc has elapsed from the start time point (time point t1).

[0120] (Fourth Modification) In the above embodiment, the holding position of the steering wheel SW by the driver is detected by the touch sensor 26, but the detection of the holding position is not limited to this. For example, the vehicle VA may be provided with a driver's seat camera that captures an image of the driver's seat, and the DSECU 20 may detect the holding position based on an image captured by the driver's seat camera.

[0121] (Fifth Modification) This support device 10 is applicable not only to the above-mentioned engine vehicles, but also to hybrid vehicles (HEVs: Hybrid Electric Vehicles), plug-in hybrid electric vehicles (PHEVs: Plug-in Hybrid Electric Vehicles), fuel cell electric vehicles (FCEVs: Fuel Cell Electric Vehicles), and battery electric vehicles (BEVs: Battery Electric Vehicles). [Explanation of symbols]

[0122] 10...driving assistance device, 20...driving assistance ECU, 30...EPS ECU, 34...steering motor, SW...steering wheel, US...steering shaft.

Claims

1. A drive device configured to change a steering angle, which is an angle of steered wheels of a vehicle, by applying a torque to a steering shaft connected to a steering wheel of the vehicle; a control unit configured to execute lane departure avoidance control for controlling the drive device to change the steering angle in order to avoid the vehicle departing from a driving lane in which the vehicle is traveling, when a predetermined start condition is satisfied; Equipped with The control unit when a holding position, which indicates a position of the driver's hands holding the steering wheel, does not satisfy a predetermined specific condition at the time when the start condition is satisfied, the lane departure avoidance control is executed so that a steering angle speed, which is a change amount of the steering angle per unit time, becomes smaller than when the holding position satisfies the specific condition at the time when the start condition is satisfied; when the driver is holding the steering wheel with both hands and the positions of the driver's hands holding the steering wheel are line-symmetrical with respect to a virtual reference line connecting a point directly above and a point directly below the steering wheel when the steering wheel is in a neutral position, the holding position is determined to satisfy the specific condition. It was configured as follows: Driving assistance device.

2. The driving assistance device according to claim 1, The control unit is configured to extend an execution time of the lane departure avoidance control by making the timing of satisfaction of the start condition earlier when the holding position does not satisfy the specific condition than when the holding position does not satisfy the specific condition. Driving assistance device.

3. The driving assistance device according to claim 1, The control unit is configured to determine that the start condition is satisfied when a width direction distance in the width direction of the travel lane from a predetermined reference point of the vehicle to an avoidance position set in the width direction of the travel lane matches a required distance that is a distance required for a lateral vehicle speed, which is a vehicle speed in a vehicle width direction of the vehicle, to become zero when a predetermined control time has elapsed. Driving assistance device.

4. The driving support device according to claim 3, the control unit is configured to determine that the start condition is satisfied before the width direction distance becomes equal to the required distance when the holding position does not satisfy the specific condition. Driving assistance device.

5. The driving support device according to claim 3, When the holding position does not satisfy the specific condition, the control unit is configured to set the avoidance position at a position a predetermined distance away in a direction opposite to a direction toward the center of the driving lane in the width direction, and to make the control time longer than when the holding position satisfies the specific condition. Driving assistance device.

6. The driving assistance device according to claim 1, the control unit is configured to, when the holding position does not satisfy the specific condition at the time point when the condition is established, reduce the magnitude of the steering angular velocity in an initial period from the time point when the condition is established until a predetermined time has elapsed, compared to the magnitude of the steering angular velocity when it is assumed that the holding position satisfies the specific condition at the time point when the condition is established, and to increase the magnitude of the steering angular velocity by an amount by which the magnitude of the steering angular velocity in the initial period has been reduced after the time point when the initial period has elapsed. Driving assistance device.

7. The driving assistance device according to claim 1, The control unit In the lane departure avoidance control, the drive device is controlled so that the magnitude of the steering angular velocity does not exceed a predetermined guard value; When the held position does not satisfy the specific condition at the time when the vehicle is established, the lane departure avoidance control is executed using a guard value that is smaller than a guard value when the held position satisfies the specific condition at the time when the vehicle is established. It was configured as follows: Driving assistance device.

Images