JP6497806B2 - Vehicle lane departure prevention control device - Google Patents

Description

  The present invention relates to a lane departure prevention control device for a vehicle that operates an actuator to prevent departure from a lane when the host vehicle is likely to depart from a traveling lane.

  In recent years, various devices that support driving have been developed and put into practical use in vehicles, and a lane departure prevention control device that prevents departure from a lane is one of such devices. For example, in Japanese Patent Laid-Open No. 2008-195402 (hereinafter referred to as Patent Document 1), when it is determined that a running vehicle deviates from the lane, an alarm torque is added to the vehicle to prevent the lane departure. A technique for obtaining a friction compensation amount from actual characteristics of steering torque and lateral acceleration in the host vehicle and setting an applied torque is disclosed.

JP 2008-195402 A

  By the way, in the lane departure prevention control device as disclosed in Patent Document 1 described above, when the friction compensation for rotating the steering system is performed so as to follow the control target value (target turning amount), the control becomes the target. Even after reaching the value, the friction compensation value is switched around the target value. Especially in the case of pinion assist type electric power steering, the motor output is converted into pinion torque via the worm gear, and the torque transmitted to the steering wheel via the universal joint and the rotation torque of the front wheels via the rack, Generally, the former has a smaller friction than the latter. Therefore, when sufficient friction compensation is performed to rotate the front wheels, the driver feels the pulsation of the controlled variable (for example, control torque) when the driver is holding the steering wheel during lane departure prevention control. There is a problem of letting it go.

  SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and provides a vehicle lane departure prevention control device capable of performing accurate lane departure prevention control with natural feeling without giving a driver a sense of incongruity such as pulsation. It is intended to provide.

One aspect of the lane departure prevention control device for a vehicle of the present invention, the lane information detecting means for detecting information on the lane on which the vehicle is traveling as the lane information with the position information of the vehicle with respect to the lane, the travel of the vehicle A driving state detecting means for detecting a state, a turning amount detecting means for detecting an actual turning amount of the host vehicle, and a target turning for preventing a departure from the lane based on the lane information and the driving state of the host vehicle. a target turning amount calculating means for calculating an amount and a control amount calculating means for calculating a control torque for operating the electric power steering motor of the order to prevent the departure from the lane based on the target turning amount, the target turning amount And a friction compensation value setting means for calculating a friction compensation value for compensating the friction of the steering system with respect to the control torque based on the actual turning amount. There are, the friction compensation value setting means, first set in advance according to the frictional force of the first friction compensation value and the steering system steering wheel side to be set in advance according to the frictional force of the steering wheel side of the steering system The first friction compensation value is selected as the friction compensation value when the absolute value of the difference between the target turning amount and the actual turning amount is greater than or equal to a preset threshold value. while setting, when the absolute value of the difference between the target turning amount and the actual turning amount is less than the threshold value is selected and set the second friction compensation value as the friction compensation value, the control amount calculation The means compensates the friction of the steering system with respect to the control torque with the friction compensation value .

  According to the vehicle lane departure prevention control apparatus of the present invention, it is possible to perform accurate lane departure prevention control with natural feeling without giving the driver a feeling of strangeness such as pulsation.

1 is a configuration explanatory diagram of a vehicle steering system according to an embodiment of the present invention. FIG. It is a functional block diagram of the steering control part which concerns on one Embodiment of this invention. It is a flowchart of the lane departure prevention control program which concerns on one Embodiment of this invention. It is a flowchart of the friction compensation value setting routine which concerns on one Embodiment of this invention. It is explanatory drawing of the own vehicle on the XZ coordinate which concerns on one Embodiment of this invention, a lane, and each parameter. 6 shows an example of lane departure prevention control according to an embodiment of the present invention, FIG. 6A is a time chart showing an example of a target yaw rate and an actual yaw rate generated in the vehicle, and FIG. 6B is a set friction. It is a time chart which shows an example of a compensation value.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  In FIG. 1, reference numeral 1 denotes an electric power steering device in which a steering angle can be set independently of a driver input. In the electric power steering device 1, a steering shaft 2 is connected to a vehicle body frame (not shown) via a steering column 3. It is rotatably supported, and one end thereof extends to the driver's seat side and the other end extends to the engine room side. A steering wheel 4 is fixed to an end portion of the steering shaft 2 on the driver's seat side, and a pinion shaft 5 is connected to an end portion extending to the engine room side.

  A steering gear box 6 extending in the vehicle width direction is disposed in the engine room, and a rack shaft 7 is inserted into and supported by the steering gear box 6 so as to be reciprocally movable. A rack (not shown) formed on the rack shaft 7 is engaged with a pinion formed on the pinion shaft 5 to form a rack and pinion type steering gear mechanism.

  The left and right ends of the rack shaft 7 protrude from the end of the steering gear box 6, and a front knuckle 9 is connected to the end via a tie rod 8. The front knuckle 9 rotatably supports left and right wheels 10L and 10R as steering wheels and is supported by a vehicle body frame so as to be steerable. Accordingly, when the steering wheel 4 is operated and the steering shaft 2 and the pinion shaft 5 are rotated, the rack shaft 7 is moved in the left-right direction by the rotation of the pinion shaft 5, and the front knuckle 9 is moved by the movement to the kingpin shaft (not shown). The left and right wheels (steering wheels) 10L and 10R are steered in the left-right direction.

  Further, an electric power steering motor (electric motor) 12 is connected to the pinion shaft 5 via an assist transmission mechanism 11, and assists and sets the steering torque applied to the steering wheel 4 by the electric motor 12. The control torque Tp is added so that the target turning amount (for example, the target yaw rate γref) is obtained. The electric motor 12 is driven by the motor drive unit 21 by outputting a control torque Tp from a steering control unit 20 described later to the motor drive unit 21.

  The steering control unit 20 is an electric power steering control function that assists the driver's steering force, a lane keep control function that causes the vehicle to travel along the target traveling path, and a departure determination line. The lane departure prevention control function and the like for preventing departure from the vehicle will be described. In particular, the configuration of the lane departure prevention control function will be described below.

The steering control unit 20 detects the lane line, and information on the lane in which the vehicle travels (the position of the lane line, the curvature, etc.), the position information of the vehicle relative to the lane (the distance to the lane line, the lane Is connected to a front recognition device 31 that detects a vehicle attitude angle (to-lane yaw angle, etc.) as lane information, a vehicle speed sensor 32 that detects a vehicle speed V, and a turning amount that detects an actual yaw rate γ that is an actual turning amount. A yaw rate sensor 33 as a detecting means and a steering wheel holding state detecting device 34 for detecting the holding and non-holding of the driver's steering wheel are connected.

  The front recognition device 31 is, for example, a set of cameras that are attached to the front of the ceiling in a vehicle interior at a constant interval and that captures a subject outside the vehicle from different viewpoints, and a stereo image processing device that processes image data from the camera. It consists of and.

  The processing of image data from the camera in the stereo image processing device of the forward recognition device 31 is performed as follows, for example. First, distance information is obtained from a pair of stereo image pairs taken in the traveling direction of the host vehicle captured by the camera from a corresponding positional shift amount, and a distance image is generated.

  In recognition of lane line data such as white lines, based on the knowledge that the lane line is brighter than the road surface, the luminance change in the width direction of the road is evaluated, and the left and right lane lines in the image plane are evaluated. The position of the line is specified on the image plane. The position (x, y, z) of the lane marking in the real space is based on the position (i, j) on the image plane and the parallax calculated with respect to this position, that is, based on the distance information. It is calculated from a known coordinate conversion formula. In the present embodiment, for example, as shown in FIG. 5, the coordinate system of the real space set based on the position of the host vehicle is the road surface directly below the center of the camera as the origin O, and the vehicle width direction is the X axis. (Left direction is “+”), vehicle height direction is Y-axis (upward direction is “+”), and vehicle length direction (distance direction) is Z-axis (front direction is “+”). At this time, the XZ plane (Y = 0) coincides with the road surface when the road is flat. The road model is expressed by dividing the lane of the host vehicle on the road into a plurality of sections in the distance direction, and connecting the left and right lane markings in each section to a predetermined approximation. In this embodiment, the example of recognizing the shape of the lane based on images from a set of cameras has been described. However, the lane shape is obtained based on image information from a monocular camera and a color camera. Also good.

  The forward recognition device 31 executes an approximation process for the acquired left and right lane markings. Specifically, the lane marking on the left side of the host vehicle is approximated by the following equation (1) by the method of least squares.

x = AL · z ² + BL · z + CL (1)
Further, the lane marking on the right side of the host vehicle is approximated by the following equation (2) by the method of least squares.

x = AR · z ² + BR · z + CR (2)
In the above equations (1) and (2), “AL” and “AR” indicate the curvature of each curve, the curvature κL of the left lane marking is 2 · AL, and the right side The curvature κR of the lane marking is 2 · AR. Therefore, the curvature κ of the lane is expressed by the following equation (3).

κ = (2 · AL + 2 · AR) / 2 = AL + AR (3)
In the equations (1) and (2), “BL” and “BR” indicate the inclinations of the respective curves in the width direction of the host vehicle, and “CL” and “CR” indicate the respective curves. The position in the width direction of the vehicle is shown (see FIG. 5).

  Further, the front recognition device 31 calculates the lane yaw angle θyaw of the host vehicle by the following equation (4).

θyaw = tan ⁻¹ ((BL + BR) / 2) (4)
As described above, the lane information detected and calculated by the forward recognition device 31 is input to the steering control unit 20, and the forward recognition device 31 is provided as lane information detection means.

  Further, the steering wheel holding state detection device 34 is provided at a plurality of locations on the steering wheel 4 as disclosed in, for example, Japanese Patent Application Laid-Open No. 2007-299048, and changes in temperature, vibration (due to pulse, etc.), pressure change, voltage change, etc. This is a steering touch sensor that detects holding or non-holding of the steering wheel 4 of the driver by detecting the above. Note that the holding or non-holding of the driver's steering wheel 4 may be detected by an in-vehicle camera or the like.

  Then, the steering control unit 20 calculates a lane curvature turning target yaw rate γref_lane necessary to travel along the lane based on each input signal described above, predicts a deviation state of the host vehicle from the lane, A target yaw rate for departure prevention γref_turn that prevents a departure from the lane according to the departure state is calculated, a target yaw rate γref is calculated based on the target yaw rate for turning lane curvature γref_lane and the target yaw rate for departure prevention behavior γref_turn, and the lane The lane curvature turning feedforward torque Tp_ff_lane is calculated based on the curvature turning target yaw rate γref_lane, the departure preventing behavior feedforward torque Tp_ff_turn is calculated based on the target yaw rate for departure prevention behavior γref_turn, and the target yaw rate feedback based on the target yaw rate γref Torque Tp_fb is calculated. Also, a first friction compensation value Tp_fsa that is preset according to the friction force on the steering wheel 10L, 10R side and a second friction compensation value that is preset according to the friction force on the steering wheel 4 side of the steering system. One of Tp_fsw is selected and set as a friction compensation value Tp_f for the steering system based on the lane information and the traveling state of the host vehicle. Then, the control torque Tp is calculated from the lane curvature turning feedforward torque Tp_ff_lane, the departure prevention behavior feedforward torque Tp_ff_turn, the target yaw rate feedback torque Tp_fb, and the friction compensation value Tp_f, and output to the motor drive unit 21.

  Therefore, as shown in FIG. 2, the steering control unit 20 calculates a target yaw rate calculation unit 20a for turning lane curvature, a target yaw rate calculation unit 20b for departure prevention behavior, a target yaw rate calculation unit 20c, and a feed forward torque calculation for turning lane curvature. The main part is composed of a part 20d, a deviation prevention behavior feedforward torque calculation part 20e, a target yaw rate feedback torque calculation part 20f, a friction compensation value setting part 20g, and a control torque calculation part 20h.

  The lane curvature turning target yaw rate calculation unit 20 a receives the lane curvature κ from the front recognition device 31 and the vehicle speed V from the vehicle speed sensor 32. Then, for example, the following yaw rate turning target yaw rate γref_lane (first target turning amount) necessary for traveling along the lane is calculated by the following equation (5), and the target yaw rate calculating unit 20c, the lane curvature turning Output to the feedforward torque calculator 20d.

γref_lane = κ · V (5)
The target yaw rate calculation unit 20b for departure prevention behavior receives the approximation result of the lane line, the yaw angle θyaw to the host vehicle, and the vehicle speed V from the vehicle speed sensor 32. Then, for example, a deviation prevention behavior target yaw rate γref_turn (second target turning amount) for preventing deviation from the lane according to the deviation state is calculated by the following equation (6) or (10): It outputs to the target yaw rate calculation unit 20c and the deviation prevention behavior feedforward torque calculation unit 20e.
・ When the lane yaw angle θyaw of the host vehicle is in the lane departure direction γref_turn = −θyaw / ttlc (6)
Here, ttlc is an expected lane departure time that deviates from the lane in the current traveling state, and is calculated by the following equation (7), for example.

ttlc = L / (V · sin (θyaw)) (7)
Here, L is the distance from the lane line to the host vehicle (lane line vehicle distance), and can be calculated by the following equation (8).

L = ((CL-CR) -TR) / 2-xv (8)
In the equation (8), TR is a tread of the vehicle, and in the embodiment of the present invention, the tire position is used as a reference for determining lane departure (see FIG. 5). Further, xv is the vehicle lateral position in the lane width direction from the center of the lane, and can be calculated by the following equation (9).

xv = (CL + CR) / 2 (9)
When the host vehicle's yaw angle θyaw to the lane is in the direction away from the lane γref_turn = − (θref_yaw−θyaw) / tref (10)
Here, θref_yaw is a yaw angle that has been set in advance by experiments and calculations, and tref is a control target time that has been set in advance by experiments and calculations.

  The target yaw rate calculation unit 20c receives the target yaw rate for turning lane curvature γref_lane from the target yaw rate calculation unit for turning lane curvature 20a, and receives the target yaw rate for departure prevention behavior γref_turn from the target yaw rate calculation unit for departure prevention behavior 20b. Then, the target yaw rate γref is calculated by the following equation (11), and is output to the target yaw rate feedback torque calculating unit 20f and the friction compensation value setting unit 20g.

γref = γref_lane + γref_turn (11)
Thus, the target yaw rate calculation unit 20c is provided as a target turning amount calculation unit.

  The lane curvature turning feedforward torque calculation unit 20d receives the lane curvature turning target yaw rate γref_lane from the lane curvature turning target yaw rate calculation unit 20a. Then, for example, the feed forward torque Tp_ff_lane for turning the lane curvature is calculated by the following equation (12), and is output to the control torque calculation unit 20h.

Tp_ff_lane = Ktrq · γref_lane (12)
Here, Ktrq is a torque conversion feedforward gain.

  The departure prevention behavior feedforward torque calculation unit 20e receives the departure prevention behavior target yaw rate γref_turn from the departure prevention behavior target yaw rate calculation unit 20b. Then, for example, the deviation prevention behavior feedforward torque Tp_ff_turn is calculated by the following equation (13), and is output to the control torque calculator 20h.

Tp_ff_turn = Ktrq · γref_turn (13)
The target yaw rate feedback torque calculator 20f receives the actual yaw rate γ from the yaw rate sensor 33, and receives the target yaw rate γref from the target yaw rate calculator 20c. Then, for example, the target yaw rate feedback torque Tp_fb is calculated by the following equation (14) and output to the control torque calculation unit 20h.

Tp_fb = Kp · (γref−γ) + Ki ·） (γref−γ) dt
+ Kd · d (γref−γ) / dt (14)
Here, Kp is a proportional gain, Ki is an integral gain, and Kd is a differential gain.

  The friction compensation value setting unit 20g receives the actual yaw rate γ from the yaw rate sensor 33, receives from the steering wheel holding state detection device 34 the determination result of whether the steering wheel 4 is held or not, and receives the determination result from the target yaw rate calculation unit 20c. A target yaw rate γref is input. Then, a friction compensation value Tp_f for compensating the friction of the steering system is set based on the target yaw rate γref and the yaw rate γ with respect to the target yaw rate γref. For example, a sign is given according to the deviation between the target yaw rate γref and the actual yaw rate (γref If “> γ”, “+”, and if “γref ≦ γ”, “-”), output to the control torque calculation unit 20h.

  Specifically, the friction compensation value Tp_f is set according to the flowchart shown in FIG. 4. In the steering system in which the first friction compensation value Tp_fsa is set as the friction compensation value Tp_f of the steering system as an initial value, the target yaw rate is set. When the absolute value | γ | of the actual yaw rate approaching the absolute value of | γref | exceeds the absolute value | γref | of the target yaw rate, the second friction compensation value Tp_fsw is set to the friction compensation value Tp_f of the steering system. The Then, from the state where the friction compensation value Tp_f is set to the second friction compensation value Tp_fsw, when the deviation between the target yaw rate γref and the actual yaw rate exceeds a preset threshold value, the first friction is again performed. The compensation value Tp_fsa is set to the friction compensation value Tp_f of the steering system.

  Here, the first friction compensation value Tp_fsa is a friction compensation value necessary for turning the front wheel of the steering system, which has been set in advance through experiments, calculations, learning, and the like, and the second friction compensation value Tp_fsw. Is a friction compensation value according to the friction force on the steering wheel side of the steering system, which is set in advance by experiment, calculation, learning, etc., and the first friction compensation value Tp_fsa> the second friction compensation value Tp_fsw. .

  The setting of the friction compensation value Tp_f will be described below with reference to the flowchart of FIG.

  First, in step (hereinafter abbreviated as “S”) 201, it is determined whether or not the first friction compensation value Tp_fsa is set to the friction compensation value Tp_f of the steering system as an initial value or a previous value, and the first friction is determined. When the compensation value Tp_fsa is set to the friction compensation value Tp_f of the steering system, the process proceeds to S202.

  In S202, it is determined whether the departure direction is the left direction or the right direction. If the departure direction is the left direction, the process proceeds to S203.

  In S203, it is determined whether or not the absolute value | γ | of the actual yaw rate approaching the absolute value | γref | of the target yaw rate exceeds the absolute value | γref | of the target yaw rate, that is, whether γ <γref or not. In this case, the process proceeds to S204, the second friction compensation value Tp_fsw is set to the friction compensation value Tp_f of the steering system (Tp_f = Tp_fsw), and the program is exited.

  Conversely, if the absolute value | γ | of the actual yaw rate approaching the absolute value | γref | of the target yaw rate has not yet exceeded the absolute value | γref | of the target yaw rate, that is, if γ ≧ γref, the program is directly exited. . In this case, Tp_f = Tp_fsa.

  On the other hand, if it is determined in the above-described S202 that the direction is rightward, the process proceeds to S205.

  In S205, it is determined whether or not the absolute value | γ | of the actual yaw rate approaching the absolute value | γref | of the target yaw rate exceeds the absolute value | γref | of the target yaw rate, that is, whether γ> γref or not. In this case, the process proceeds to S206, the second friction compensation value Tp_fsw is set to the friction compensation value Tp_f of the steering system (Tp_f = Tp_fsw), and the program is exited.

  On the other hand, if the absolute value | γ | of the actual yaw rate approaching the absolute value | γref | of the target yaw rate has not yet exceeded the absolute value | γref | of the target yaw rate, that is, if γ ≦ γref, the program is directly exited. . In this case, Tp_f = Tp_fsa.

  In S201 described above, when it is determined that the first friction compensation value Tp_fsa is not set to the steering system friction compensation value Tp_f as the initial value or the previous value, that is, the second friction compensation value Tp_fsw is steered. When the friction compensation value Tp_f of the system is set, the process proceeds to S207 to determine whether or not the steering wheel 4 is in the holding state.

  If the steering wheel 4 is in the holding state, the program is exited as it is (that is, Tp_f = Tp_fsw). Conversely, if the steering wheel 4 is not in the holding state, the process proceeds to S208.

  In S208, the absolute value | γref−γ | of the deviation between the target yaw rate γref and the actual yaw rate γ is compared with a threshold value γcc previously set by experiment, calculation, etc. If | γref−γ | ≧ γcc, S209 Then, the first friction compensation value Tp_fsa is set to the friction compensation value Tp_f of the steering system (Tp_f = Tp_fsa), and the program is exited.

  Conversely, if | γref−γ | <γcc, the program exits as it is. In this case, Tp_f = Tp_fsw.

  Thus, the friction compensation value setting unit 20g is provided as friction compensation value setting means.

  The control torque calculation unit 20h receives the lane curvature turning feedforward torque Tp_ff_lane from the lane curvature turning feedforward torque calculation unit 20d, and the departure prevention behavior feedforward torque Tp_ff_turn from the departure prevention behavior feedforward torque calculation unit 20e. The target yaw rate feedback torque calculation unit 20f receives the target yaw rate feedback torque Tp_fb, and the friction compensation value setting unit 20g receives the friction compensation value Tp_f. Then, the control torque Tp is calculated by the following equation (15) and output to the motor drive unit 21.

Tp = Tp_ff_lane + Tp_ff_turn + Tp_fb + Tp_f (15)
Thus, in the embodiment of the present invention, the control torque calculator 20h is provided as a control amount calculator.

  Next, the lane departure prevention control executed by the steering control unit 20 will be described with reference to the flowchart of FIG.

  First, in S101, the lane curvature turning target yaw rate calculation unit 20a calculates the lane curvature turning target yaw rate γref_lane necessary for traveling along the lane according to the above-described equation (5).

  Next, the process proceeds to S102, and the target yaw rate calculation unit for departure prevention behavior 20b uses the above-described equation (6) or (10) to prevent departure from the lane according to the departure state. A target yaw rate γref_turn is calculated.

  Next, proceeding to S103, the target yaw rate calculation unit 20c calculates the target yaw rate γref according to the above-described equation (11).

  Next, in S104, the lane curvature turning feedforward torque calculating unit 20d calculates the lane curvature turning feedforward torque Tp_ff_lane according to the above-described equation (12).

  Next, proceeding to S105, the departure prevention behavior feedforward torque calculation unit 20e calculates the departure prevention behavior feedforward torque Tp_ff_turn by the above-described equation (13).

  Next, in S106, the target yaw rate feedback torque calculation unit 20f calculates the target yaw rate feedback torque Tp_fb by the above-described equation (14).

  Next, in S107, the friction compensation value Tp_f is set by the friction compensation value setting unit 20g.

  Then, the control torque calculation unit 20h calculates the control torque Tp according to the above-described equation (15) and outputs it to the motor drive unit 21 to exit the program.

  As described above, in the embodiment of the present invention, the target yaw rate γref_lane for turning the lane curvature necessary for traveling along the lane is calculated, the deviation state from the lane of the own vehicle is predicted, and the deviation state is determined according to the deviation state. The target yaw rate γref_turn for departure prevention behavior that prevents deviation from the lane is calculated, and the target yaw rate γref is calculated based on the target yaw rate γref_lane for turning lane curvature and the target yaw rate γref_turn for departure prevention behavior, and the target yaw rate for turning lane curvature The feed forward torque Tp_ff_lane for turning lane curvature is calculated based on γref_lane, the feed forward torque Tp_ff_turn for departure prevention behavior is calculated based on the target yaw rate for departure prevention behavior γref_turn, and the target yaw rate feedback torque Tp_fb is calculated based on the target yaw rate γref . Also, a first friction compensation value Tp_fsa that is preset according to the friction force on the steering wheel 10L, 10R side and a second friction compensation value that is preset according to the friction force on the steering wheel 4 side of the steering system. One of Tp_fsw is selected and set as a friction compensation value Tp_f for the steering system based on the lane information and the traveling state of the host vehicle. Then, the control torque Tp is calculated from the lane curvature turning feedforward torque Tp_ff_lane, the departure prevention behavior feedforward torque Tp_ff_turn, the target yaw rate feedback torque Tp_fb, and the friction compensation value Tp_f.

  As shown in FIG. 6A, for example, when the target yaw rate γref of γref ≧ 0 is output (time t0 to t0) in order to turn the vehicle to the left in order to prevent deviation from the right lane line. t2) The actual yaw rate γ of the vehicle approaches the target yaw rate γref and approaches the target yaw rate γref at time t1. From time t0 to time t1, as shown in FIG. 6B, the first friction compensation value Tp_fsa is set as the friction compensation value Tp_f of the steering system. However, after the actual yaw rate γ exceeds the target yaw rate γref at time t1, the second friction compensation value Tp_fsw is set to the steering system friction compensation value Tp_f. When the actual yaw rate γ that exceeds the target yaw rate γref converges to the target yaw rate γref, and the difference between the target yaw rate γref and the yaw rate γ exceeds a preset threshold at time t2, again, The first friction compensation value Tp_fsa is set as the friction compensation value Tp_f of the steering system (note that the sign of the friction compensation value Tp_f depends on the deviation between the target yaw rate γref and the actual yaw rate γ). Thereafter, when the actual yaw rate γ of the vehicle approaches and approaches the target yaw rate γref again and falls below the target yaw rate γref at time t3, the second friction compensation value Tp_fsw is set to the friction compensation value Tp_f of the steering system. The Therefore, in the departure prevention control, after the control reaches the target value, the second friction compensation value Tp_fsw smaller than the first friction compensation value Tp_fsa is set as the friction compensation value Tp_f of the steering system. Even if the driver grips the steering wheel 4 during the departure prevention control, it is possible to reliably prevent the driver from feeling the pulsation of the control torque Tp, and a natural feel without giving the driver a sense of incongruity. Accurate lane departure prevention control can be performed with a ring. In particular, in the electric power steering device of the pinion assist type, the difference between the friction force from the pinion shaft 5 to the steering wheel 4 and the friction force from the pinion shaft 5 to the steering wheels 10L and 10R is large, and the friction force on the steering wheel 4 side is large. Since it is smaller than the frictional force on the steering wheels 10L, 10R side, the pulsation of the control torque Tp for controlling the steering wheels 10L, 10R may appear remarkably on the steering wheel 4 side, making the driver feel uncomfortable. The present application reliably prevents the occurrence of such a sense of incongruity.

DESCRIPTION OF SYMBOLS 1 Electric power steering apparatus 2 Steering shaft 4 Steering wheel 5 Pinion shaft 10L, 10R Wheel (steering wheel)
DESCRIPTION OF SYMBOLS 12 Electric motor 20 Steering control part 20a Target yaw rate calculation part for lane curvature turning 20b Target yaw rate calculation part for deviation prevention behavior 20c Target yaw rate calculation part (target turning amount calculation means)
20d Feed forward torque calculation unit for turning lane curvature 20e Feed forward torque calculation unit for departure prevention behavior 20f Target yaw rate feedback torque calculation unit 20g Friction compensation value setting unit (friction compensation value setting means)
20h Control torque calculation unit (control amount calculation means)
21 motor drive unit 31 forward recognition device (lane information detection means)
32 Vehicle speed sensor (running state detection means)
33 Yaw rate sensor (running state detection means)
34 Steering wheel holding state detection device

Claims (5)

And lane information detecting means for detecting information on the lane on which the vehicle is traveling as the lane information with the position information of the vehicle with respect to the lane,
A running condition detecting means for detecting a running condition of the vehicle,
A turning amount detecting means for detecting an actual turning amount of the host vehicle;
Target turning amount calculation means for calculating a target turning amount for preventing deviation from the lane based on the lane information and the traveling state of the host vehicle;
And a control amount calculating means for calculating a control torque for operating the electric power steering motor of the order to prevent the departure from the lane based on the target turning amount,
Friction compensation value setting means for calculating a friction compensation value for compensating the friction of the steering system with respect to the control torque based on the target turning amount and the actual turning amount;
In a vehicle lane departure prevention control device comprising:
The friction compensation value setting means has a first friction compensation value set in advance according to the friction force on the steering wheel side of the steering system and a second value set in advance according to the friction force on the steering wheel side of the steering system. The first friction compensation value is selected and set as the friction compensation value when the absolute value of the difference between the target turning amount and the actual turning amount is greater than or equal to a preset threshold value. on the other hand, when the absolute value of the difference between the target turning amount and the actual turning amount is less than the threshold value is selected and set the second friction compensation value as the friction compensation value,
The control amount calculating means compensates the friction of the steering system with respect to the control torque with the friction compensation value.
Lane departure prevention control device for a vehicle, characterized and this. The friction compensation value setting means, and selects set the absolute value of the target turning amount as above Symbol friction compensation value the first friction compensation value to above the absolute value of the actual turning amount above lane departure prevention control device according to claim 1 Symbol placement of the vehicle. 3. The lane departure prevention of a vehicle according to claim 1, wherein an absolute value of the first friction compensation value is larger than an absolute value of the second friction compensation value. Control device. The friction compensation value setting means, the driver in the case of holding the steering wheel, according to claim 1 or claims, characterized in that for selecting and setting the second friction compensation value as an upper Symbol friction compensation value Item 4. The vehicle lane departure prevention control device according to any one of Items 3 to 4. The target turning amount calculation means calculates a first target turning amount necessary to travel along the lane based on the lane information and the traveling state of the host vehicle, and the lane information and the own vehicle based on the running state predicts the deviation state from the lane of the vehicle, calculates a second target turning amount to prevent departure from the lane in accordance with the該逸de state, the first target turning amount a lane departure prevention control device for a vehicle according to any one of claims 1 to 4, and calculates the target turning amount based on the second target turning amount.

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