JP2013078999A - Steering support device - Google Patents

Abstract

When a vehicle is traveling on a canted road surface, a steering torque and a steering angle change amount are excessively increased when a guidance torque for turning the vehicle is applied to a lower road surface. A steering assist device that can be suppressed is provided.
A steering angular velocity threshold value setting unit 52 sets a steering angular velocity threshold value Vh _th based on a guidance torque command value T _G ^* and a vehicle speed V. The speed deviation calculator 52 calculates a deviation ΔVh between the absolute value | Vh | of the steering angular velocity calculated by the steering angular velocity calculator 51 and the steering angular velocity threshold Vh _th . The gain setting unit 54 calculates the gain G based on the speed deviation ΔVh _h . Gain multiplication unit 55, by multiplying the gain G to the guidance torque command value T _G ^*, obtaining a final guidance torque command value T _G ^*.
[Selection] Figure 2

Description

  The present invention relates to a steering assist device for a vehicle, and more particularly to a steering assist device for preventing a running vehicle from departing from a lane.

  There has been proposed a steering assist device for preventing a running vehicle from deviating from the lane. As this type of steering assist device, the road surface information and the relative position information between the vehicle and the lane are acquired based on the captured image of the camera mounted on the vehicle, and the direction to prevent the vehicle from deviating from the lane is prevented. In some cases, a steering torque is applied to the steering mechanism for turning the vehicle. The magnitude and direction of the guidance torque are determined by, for example, relative position information between the vehicle and the lane, vehicle speed, and the like.

JP 2008-6857 A Japanese Patent No. 3209154 Japanese Patent No. 4200903

  In the steering assist device described above, it is difficult to detect the road surface cant from the captured image of the camera, and thus the guidance torque cannot be set in consideration of the influence of the road surface cant. For this reason, when the vehicle is traveling on a road surface with a cant, when a guidance torque for turning the vehicle to the lower side of the road surface is given, compared to when traveling on a road surface without a cant Further, the steering angular velocity and the steering angle change amount with respect to the guidance torque are increased, and the vehicle may be staggered.

  The object of the present invention is that when the vehicle is traveling on a canted road surface, the steering angular velocity and the amount of change in the steering angle are excessively large when guidance torque for turning the vehicle to the lower side of the road surface is applied. It is providing the steering assistance device which can suppress becoming.

In order to achieve the above object, the invention according to claim 1 includes a steering actuator (15) for applying a guidance torque for preventing lane departure to the steering mechanism (4), and a steering angular velocity (Vh). Steering angular velocity detecting means (21, 51) for detecting the vehicle, command value setting means (42) for setting a guidance torque command value ( _TG ^* ) when the vehicle may deviate from the lane, and the command value Steering angular velocity threshold setting means (52) for setting a steering angular velocity threshold (Vh _th ) based on the guidance torque command value set by the setting means, and the steering angular velocity detected by the steering speed detecting means is the steering angular velocity. When the steering angular velocity threshold set by the threshold setting means is greater than a predetermined value, the guidance torque command value set by the command value setting means is reduced. The steering assist device includes correction means (53, 54, 55) for correction and control means (46) for controlling the steering actuator based on the guidance torque command value corrected by the correction means. . In addition, although the alphanumeric character in parentheses represents a corresponding component in an embodiment described later, of course, the scope of the present invention is not limited to the embodiment. The same applies hereinafter.

  In the present invention, when the vehicle is traveling on a canted road surface, the steering angular velocity detected by the steering speed detecting means when the guidance torque for turning the vehicle to the lower side of the road surface is given. When the steering angular velocity threshold value set by the steering angular velocity threshold value setting means is larger than a predetermined value, the guidance torque command value set by the command value setting means is reduced and corrected. Therefore, when the vehicle is traveling on a canted road surface, the steering angular velocity and the amount of change in the steering angle become excessively large when a guidance torque for turning the vehicle to the lower side of the road surface is given. Can be suppressed. Thereby, it can suppress or prevent that a vehicle fluctuates.

  The steering actuator may be a steering assist motor of an electric power steering apparatus.

FIG. 1 is a schematic diagram showing a schematic configuration of an electric power steering device to which a steering assist device according to an embodiment of the present invention is applied. FIG. 2 is a block diagram showing an electrical configuration of the ECU. FIG. 3 is an explanatory diagram for explaining the operation of the TLC calculation unit. FIG. 4 is a graph showing a setting example of the guidance torque command value with respect to the vehicle speed. FIG. 5A is a graph showing the guidance torque command value and the change in steering torque when the guidance torque command value for turning the vehicle to the lower side of the road surface is set by the guidance torque command value setting unit; FIG. 5B is a graph showing the guidance torque command value and the change in the steering torque when the guidance torque command value for turning the vehicle to the higher road surface is set by the guidance torque command value setting unit. FIG. 6A is a graph showing an example of setting the steering angular velocity threshold value with respect to the guidance torque command value, and FIG. 6B is a graph showing an example of the gain characteristic of the steering angular velocity threshold value with respect to the vehicle speed. FIG. 7 is a graph showing a setting example of a gain for correcting the guidance torque command value with respect to the speed deviation. FIG. 8 is a graph showing a setting example of the assist torque command value with respect to the detected steering torque. FIG. 9 shows changes in the corrected guidance torque command value and steering torque when the guidance torque command value in the left steering direction for turning the vehicle to the lower side of the road surface is set by the guidance torque command value setting unit 42. It is a graph which shows.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.
FIG. 1 is a schematic diagram showing a schematic configuration of an electric power steering device 1 to which a steering assist device according to an embodiment of the present invention is applied.
The electric power steering apparatus 1 includes a steering wheel 2 as a steering member for steering the vehicle, a steering mechanism 4 that steers the steered wheels 3L and 3R in conjunction with the rotation of the steering wheel 2, and a driver. And a steering assist device 5 for assisting the steering.

  The steering wheel 2 and the steering mechanism 4 are connected via a steering shaft 6, a universal joint 7, an intermediate shaft 8 and a universal joint 9. A steering angle sensor 21 for detecting a steering angle θh, which is a rotation angle of the steering shaft 6, is disposed around the steering shaft 6. In this embodiment, the rudder angle sensor 21 detects the amount of rotation (rotation angle) of the steering shaft 6 in both forward and reverse directions from the neutral position of the steering shaft 6, and the amount of rotation from the neutral position to the left direction is detected. For example, a positive value is output, and the amount of rotation from the neutral position to the right is output as a negative value.

  The steering mechanism 4 includes a pinion shaft 11 connected to the universal joint 9, a rack shaft 12 having a rack 12 a meshing with the pinion 11 a at the tip of the pinion shaft 11, and tie rods 13 </ b> L and 13 </ b> R at a pair of ends of the rack shaft 12. And knuckle arms 14L and 14R connected to each other. The rack shaft 12 extends in the left-right direction of the vehicle. The pinion shaft 11 is provided with a torque sensor 22 for detecting the steering torque Th.

  When the steering wheel 2 is steered (rotated), this rotation is transmitted to the steering mechanism 4 via the steering shaft 6 or the like. In the steering mechanism 4, the rotation of the pinion 11a is converted into the movement of the rack shaft 12 in the axial direction, and the corresponding knuckle arms 14L and 14R rotate through the tie rods 13L and 13R, respectively. Accordingly, the corresponding steered wheels 3L and 3R connected to the knuckle arms 14L and 14R are steered, respectively.

  The steering assist device 5 includes a steering assist motor 15 disposed coaxially with the rack shaft 12, and a ball screw mechanism that converts the output torque of the steering assist motor 15 into movement in the rack axis direction and transmits the motion to the rack shaft 12 ( (Not shown). The steering assist motor (steering actuator) 15 is a three-phase brushless motor. In this embodiment, the steering assist motor 15 is used as an actuator for generating a steering assist force (assist torque) and an actuator for generating a guidance torque for preventing the vehicle from departing from the lane. Also used as

  A rotation angle sensor 23 made of, for example, a resolver for detecting the rotation angle θs of the rotor of the steering assist motor 15 is disposed in the vicinity of the steering assist motor 15. When the steering assist motor 15 is driven to rotate, this rotation is converted into an axial movement of the rack shaft 12 by the ball screw mechanism. That is, the torque of the steering assist motor 15 is applied to the steering mechanism 4. Thereby, the steered wheels 3L and 3R are steered.

The electric power steering apparatus 1 further includes a vehicle speed sensor 24 for detecting the vehicle speed V, a camera 25 mounted on the vehicle, an image processing unit 26, and an ECU (Electronic Control) for controlling the steering assist motor 15. Unit: an electronic control unit) 27.
The camera 25 is disposed, for example, inside the windshield in the passenger compartment with the vehicle facing diagonally forward and downward. The camera 25 images the road ahead of the vehicle. The camera 25 is a CCD camera, for example.

  Based on the image captured by the camera 25, the image processing unit 26 recognizes a pair of lane boundary lines (white lines) indicating the lane in which the vehicle is traveling, and acquires relative position information between the vehicle and the lane. The relative position information includes a lateral displacement to a lane boundary indicated by D in FIG. 3, a yaw angle with respect to the lane boundary indicated by φ in FIG. Details of the lateral displacement D to the lane boundary and the yaw angle φ with respect to the lane will be described later.

The ECU 27 includes a steering angle θh detected by the steering angle sensor 21, a steering torque Th detected by the torque sensor 22, a rotation angle θs of the rotor of the steering assist motor 15 detected by the rotation angle sensor 23, and a vehicle speed sensor 24. And the relative position information (D, φ, etc.) acquired by the image processing unit 26 are input.
FIG. 2 is a block diagram showing an electrical configuration of the ECU 27.

The ECU 27 includes a microcomputer 31 and a drive circuit (inverter circuit) 32 that is controlled by the microcomputer 31 and supplies electric power to the steering assist motor 15.
The microcomputer 31 includes a CPU and a memory (such as a ROM and a RAM), and functions as a plurality of function processing units by executing a predetermined program. The plurality of function processing units include a TLC calculation unit 41, a guidance torque command value setting unit 42, a guidance torque command value correction unit 43, an assist torque command value setting unit 44, a torque addition unit 45, and feedback control. Part 46 is included.

Based on the lateral displacement D to the lane boundary line and the yaw angle φ with respect to the lane line, the TLC calculation unit 41 predicts a lane departure time (TLC: Time to Line Crossing) that is an expected time until the vehicle reaches the lane boundary line. Is calculated.
With reference to FIG. 3, the lateral displacement D to the lane boundary and the yaw angle φ with respect to the lane will be described. When the direction of the vehicle 100 with respect to the direction in which the lane extends is the left direction, the lane boundary line 101 on the left side of the lane is set as the attention lane boundary line, and the direction of the vehicle 100 with respect to the direction in which the lane extends is the right direction. Uses the lane boundary 102 on the right side of the lane as the target lane boundary. In the example of FIG. 3, the lane boundary line 101 on the left side of the lane is the attention lane boundary line. The lateral displacement D up to the lane boundary is the corner on the lane boundary side (left corner in the example of FIG. 3) of the left and right corners on the front side of the vehicle 100 and the lane boundary line (lane in the example of FIG. 3). The distance to the lane boundary line 101) on the left side. The yaw angle φ with respect to the lane is an angle formed by the center line extending in the front-rear direction of the vehicle and the lane boundary line of interest.

  A position of the corner (left corner in the example of FIG. 3) on the lane boundary line side of the left and right corners on the front side of the vehicle 100 is defined as A. Further, when the vehicle travels while maintaining the current yaw angle φ, the corner on the attention lane boundary side among the left and right corners on the front side of the vehicle 100 (the left corner in the example of FIG. 3) is the attention lane boundary line ( In the example of FIG. 3, the position reaching the lane boundary line 101) on the left side of the lane is defined as B. Assuming that the vehicle speed is constant, the predicted lane departure time TLC is a value obtained by dividing the distance L between AB by the vehicle speed V. Since L · sinφ = D is established between L and D, the predicted lane departure time TLC is expressed by the following equation (1).

TLC = L / V
= D / (V · sinφ) (1)
That is, the TLC calculating unit 41 calculates the predicted lane departure time TLC based on the equation (1). Note that the predicted lane departure time TLC may be calculated based on an arithmetic expression other than the expression (1).

The guidance torque command value setting unit 42 determines that the vehicle may deviate from the lane when the predicted lane departure time TLC calculated by the TLC calculation unit 41 is smaller than a predetermined threshold, and sets the vehicle speed V to the vehicle speed V. Based on this, a guidance torque command value T _G ^* is set. However, the guidance torque command value setting unit 42, when the lane departure prevention control based on the guidance torque command value T _G ^* the previously set not finished, not set the guidance torque command value T _G ^*.

FIG. 4 is a graph showing a setting example of the guidance torque command value with respect to the vehicle speed.
Guidance torque command value setting unit 42 creates a pattern of guidance torque command value _TG ^* with respect to time based on vehicle speed V, and sets guidance torque command value _TG ^* according to the created pattern. In this embodiment, the guidance torque command value T _G ^* is a positive value when the lane boundary line of interest is the lane boundary line on the right side of the lane and a guidance torque for steering leftward from the steering assist motor 15 is generated. When the attention lane boundary is the lane boundary on the left side of the lane and the guidance torque for steering in the right direction is generated from the steering assist motor 15, the lane boundary is set to a negative value.

The pattern of the guidance torque command value T _G ^* with respect to time includes a first section in which the absolute value | T _G ^* | of the guidance torque command value is gradually increased to a maximum value determined according to the vehicle speed V, and a first value that maintains the maximum value. 2 sections and a third section in which the absolute value | T _G ^* | of the guidance torque command value is gradually decreased from the maximum value to zero. The maximum value of the absolute value | _TG ^* | of the guidance torque command value is set to increase as the vehicle speed increases.

In this embodiment, the lengths of the first section, the second section, and the third section are set in advance, and are constant regardless of the magnitude of the maximum value of the absolute value | T _G ^* | of the guidance torque command value. It is. Note that the length of the second section may be changed according to the yaw angle φ with respect to the lane. For example, the length of the second section may be increased as the absolute value of the yaw angle φ with respect to the lane increases.

The guidance torque command value correction unit 43 will be described. Assume that a guidance torque command value _TG ^* for turning the vehicle to the lower side of the road surface is set as indicated by the broken line Q1 in FIG. 5A when the vehicle is traveling on a road surface with a cant. In this example, the guidance torque command value T _G ^* is a command value for generating guidance torque for leftward steering. When the steering assist motor 15 is controlled using the guidance torque command value T _G ^* as it is, the steering angle θh changes as shown by a curve S1 in FIG. 5A. As a result, the steering angular velocity and the amount of change in the steering angle become larger than when the vehicle is traveling on a road surface without a cant. If the steering angular velocity and the steering angle change amount become excessively large, the vehicle may be staggered.

On the other hand, when the vehicle is traveling on a canted road surface, as indicated by the broken line Q2 in FIG. 5B, a guidance torque command value T _G ^* for turning the vehicle to the higher side of the road surface is set. . In this example, the guidance torque command value T _G ^* is a command value for generating guidance torque for rightward steering. When the steering assist motor 15 is controlled using the guidance torque command value T _G ^* as it is, the steering angle θh changes as shown by a curve S2 in FIG. 5B. If it does so, compared with the case where the vehicle is drive | working the road surface without a cant, a steering angular velocity and a steering angle change amount will become small.

As shown in FIG. 5A, when the guidance torque command value T _G ^* for turning the vehicle to the lower road surface is set, the guidance torque command value correction unit 43 has excessive steering angular velocity and steering angle variation. The guidance torque command value _TG ^* is corrected in order to suppress the increase of the torque. Specifically, the guidance torque command value correction unit 43 sets the guidance torque set by the guidance torque command value setting unit 42 when the absolute value of the actual steering angular velocity is greater than a predetermined value by a steering angular velocity threshold described later. The command value _TG ^* is reduced and corrected.

Returning to FIG. 2, the guidance torque command value correction unit 43 includes a steering angular velocity calculation unit 51, a steering angular velocity threshold setting unit 52, a deviation calculation unit 53, a gain setting unit 54, and a gain multiplication unit 55. .
The steering angular velocity calculation unit 51 calculates the steering angular velocity Vh of the steering wheel 2 based on the steering angle θh detected by the steering angle sensor 21. Specifically, the steering angle θh detected by the rudder angle sensor 21 is repeatedly sampled every predetermined sampling period. When the steering angle θh is sampled, a difference from the steering angle one sampling period before is obtained. Then, the steering angular velocity Vh is obtained by dividing this difference by the sampling period.

The steering angular velocity threshold setting unit 52 sets the steering angular velocity threshold Vh _th based on the guidance torque command value T _G ^* set by the guidance torque command value setting unit 42 and the vehicle speed V detected by the vehicle speed sensor 24.
6A and 6B are graphs showing an example of setting the steering angular velocity threshold with respect to the guidance torque command value and the vehicle speed. 6A shows the characteristic of the basic value of the steering angular velocity threshold value, and FIG. 6B shows the vehicle speed gain multiplied by the basic value obtained according to the characteristic of FIG. 6A.

As shown in FIG. 6A, in the region where the absolute value | T _G ^* | of the guidance torque command value is less than the predetermined value C, the basic value of the steering angular velocity threshold is the absolute value | T _G of the guidance torque command value. ^* It is set to increase monotonically from the lower limit value to the upper limit value as | increases. In a region where the absolute value of the guidance torque command value | T _G ^* |

  Furthermore, as shown in FIG. 6B, the vehicle speed gain multiplied by the basic value of the steering angular velocity threshold is 1 as the upper limit value in the region where the vehicle speed V is less than the first predetermined speed V1 (for example, 60 km / h). .0 is fixed. Further, in a region where the vehicle speed V is equal to or higher than the second predetermined speed V2 which is larger than the first predetermined speed V1, the vehicle speed gain is fixed to the lower limit value (> 0). In the region where the vehicle speed V is equal to or higher than the first predetermined speed V1 and lower than the second predetermined speed V2, the vehicle speed gain is set so as to monotonously decrease from the upper limit value to the lower limit value as the vehicle speed V increases. ing. The vehicle speed gain is decreased in the region where the vehicle speed V is equal to or higher than the first predetermined speed V1 when the vehicle speed V is medium or higher and the self-aligning torque and the force necessary for steering are increased as the vehicle speed V increases. This is because the steering angular velocity threshold value is decreased.

As described above, the steering angular velocity threshold value Vh _th is set by multiplying the basic value of the steering angular velocity threshold value by the vehicle speed gain. However, the basic value of the steering angular velocity threshold value may be used as it is as the steering angular velocity threshold value Vh _th without applying the vehicle speed gain.
The deviation calculating unit 53 subtracts the steering angular velocity threshold Vh _th set by the steering angular velocity threshold setting unit 52 from the absolute value | Vh | of the steering angular velocity calculated by the steering angular velocity calculating unit 51 to thereby obtain a velocity deviation ΔVh (= | Vh | −Vh _th ) is calculated.

The gain setting unit 54 sets a gain G for guidance torque command value correction based on the speed deviation ΔVh. Gain multiplication unit 55, by multiplying the gain G for the set guidance torque command value correction by the gain setting unit 54, a guidance torque command value T _G ^* that is set by the guidance torque command value setting unit 42, the final A simple guidance torque command value T _G ^* 'is calculated.

FIG. 7 is a graph showing a setting example of the gain G for correcting the guidance torque command value with respect to the speed deviation ΔVh.
When the speed deviation ΔVh is small, that is, when the speed deviation ΔVh is less than the first specified value E (E> 0), the gain G is fixed to the upper limit value of 1.0. When the speed deviation ΔVh is large, that is, when the speed deviation ΔVh is greater than or equal to the second specified value F (F> E), the gain G is fixed to the lower limit value (> 0). Within a range where the speed deviation ΔVh is greater than or equal to the first specified value E and less than the second specified value F, the gain G is set to monotonously decrease from the upper limit value to the lower limit value as the speed deviation ΔVh increases. ing.

Therefore, when the absolute value | Vh | of the steering angular velocity is larger than the steering angular velocity threshold value Vh _th by the first specified value E or more, the gain G is set to a value smaller than 1.0, so the guidance torque command value T _G ^* Is reduced and corrected.
Assist torque command value setting unit 44, based on the vehicle speed V detected by the detected steering torque Th and the vehicle speed sensor 24 which is detected by the torque sensor 22, sets the assist torque command value T _A ^*.

FIG. 8 is a graph showing a setting example of the assist torque command value with respect to the detected steering torque.
For the detected steering torque Th, for example, the torque for steering in the left direction is a positive value, and the torque for steering in the right direction is a negative value. The assist torque command value T _A ^* is a positive value when assist torque for steering leftward from the steering assist motor 15 is generated, and assist torque for steering rightward is generated from the steering assist motor 15. Sometimes it is negative.

The assist torque command value AT ^* takes a positive value for a positive value of the detected steering torque Th and takes a negative value for a negative value of the detected steering torque Th. When the detected steering torque Th is a minute value in the range of -T1 to T1, the assist torque is set to zero. The detection in the region other than the range of the steering torque Th is -T1～T1, the assist torque command value T _A ^*, the absolute value becomes larger of the detected steering torque Th, it is set such that the absolute value becomes larger Yes. Moreover, ^* the assist torque command value T _A is as the vehicle speed V detected by the vehicle speed sensor 24 is large, it is set such that the absolute value becomes smaller.

The torque addition unit 45 adds the assist torque command value T _A ^* set by the assist torque command value setting unit 44 and the guidance torque command value T _G ^* calculated by the gain multiplication unit 55, thereby generating a torque command. The value T _M ^* (= T _A ^* + T _G ^* ) is calculated.
The feedback control unit 46 includes a torque command value T _M ^* calculated by the torque adding unit 45, a rotation angle θs of the steering assist motor 15 detected by the rotation angle sensor 23, and a motor flowing through the steering assist motor 15. An output signal of the current sensor 28 for detecting current is input.

The feedback control unit 46 drives the drive circuit 32 so that the torque generated by the steering assist motor 19 is equal to the torque command value T _M ^* calculated by the torque addition unit 45. Specifically, the feedback control unit 46 calculates the current command value by dividing the torque command value T _M ^* by the torque coefficient of the steering assist motor 15, and the motor current obtained from the output signal of the current sensor 28 is calculated. The drive circuit 32 is driven so as to be equal to the current command value.

In the above configuration, when the predicted lane departure time TLC calculated by the TLC calculation unit 41 becomes smaller than a predetermined threshold, the guidance torque command value setting unit 42 is based on the vehicle speed V detected by the vehicle speed sensor 24. Set the guidance torque command value T _G ^* . The steering angular velocity threshold setting unit 52 sets the steering angular velocity threshold Vh _th based on the guidance torque command value T _G ^* and the vehicle speed V. The speed deviation calculation unit 52 calculates a deviation (speed deviation ΔVh) between the absolute value | Vh | of the steering angular velocity calculated by the steering angular velocity calculation unit 51 and the steering angular velocity threshold Vh _th . The gain setting unit 54 calculates a gain G for correcting the guidance torque command value based on the speed deviation ΔVh. The gain multiplication unit 55 obtains a final guidance torque command value T _G ^* ′ by multiplying the guidance torque command value T _G ^* by the gain G for correcting the guidance torque command value.

That is, when the absolute value | Vh | of the actual steering angular velocity becomes larger than the steering angular velocity threshold Vh _th by a predetermined value or more, the guidance torque command value T _G ^* set by the guidance torque command value setting unit 42 is corrected to be reduced. As a result, when the vehicle is traveling on a canted road surface, when the guidance torque command value T _G ^* for turning the vehicle to the lower side of the road surface is set, the steering angular velocity and the steering angle change amount are set. Can be prevented from becoming excessively large.

This point will be described more specifically with reference to FIG. When the vehicle is traveling on a canted road surface, the guidance torque command value setting unit 42 sets a guidance torque command value _TG ^* in a direction to turn the vehicle to the lower side of the road surface, as indicated by a broken line Q1. Suppose that When the guidance torque command value T _G ^* is not corrected, the steering angle θh increases (changes) more rapidly than when the vehicle is traveling on a road surface without a cant, as indicated by a broken line S1. As a result, the vehicle may be staggered.

In this embodiment, when the absolute value | Vh | of the steering angular velocity is larger than the steering angular velocity threshold value Vh _th by a predetermined value or more, the guidance torque command value T _G ^* set by the guidance torque command value setting unit 42 is corrected to be reduced. For this reason, the guidance torque command value T _G ^* is reduced and corrected as shown by the solid line Q3. As a result, the steering angle θh changes gently as shown by the solid line S3. As a result, the vehicle can be prevented from wobbling.

  As mentioned above, although one Embodiment of this invention was described, this invention can also be implemented with another form. For example, although the guidance torque command value setting unit 42 and the assist torque command value setting unit 44 set the guidance torque command value and the assist torque command value, respectively, the current command value and the assist torque corresponding to the guidance torque command value, respectively. A current command value corresponding to the command value may be set.

In the above embodiment, the guidance torque command value setting unit 42 sets the guidance torque command value T _G ^* based on the vehicle speed V. However, the guidance torque command value T _G based on the relative positional relationship between the lane and the vehicle. ^{* May} be set. For example, the guidance torque command value setting unit 42 sets a guidance torque command value T _G ^* for reducing the deviation amount based on the deviation amount between the lane width center line and the vehicle width center. Also good.

In the above embodiment, the pattern of the guidance torque command value T _G ^* with respect to time is set to a trapezoidal shape as shown in FIG. 4, but is not limited to this, and is set to a sinusoidal pattern, for example. May be.
In the above embodiment, the timing for setting the guidance torque command value T _G ^* (the timing for performing the lane departure prevention control) is determined based on the predicted lane departure time TLC. However, the guidance torque command value T _G ^* is determined ^. May be determined based on information other than the estimated lane departure time TLC.

  In addition, various design changes can be made within the scope of matters described in the claims.

  3L, 3R ... steered wheel, 15 ... steering assist motor, 21 ... steering angle sensor, 42 ... guidance torque command value setting unit, 46 ... feedback control unit, 51 ... steering angular velocity calculation unit, 52 ... steering angular velocity threshold setting unit, 53 ... Deviation calculation unit, 54 ... Gain setting unit, 55 ... Gain multiplication unit

Claims (2)

A steering actuator for applying a guidance torque for preventing lane departure to the steering mechanism;
Steering angular velocity detection means for detecting the steering angular velocity;
Command value setting means for setting a guidance torque command value when the vehicle may deviate from the lane;
Steering angular velocity threshold setting means for setting a steering angular velocity threshold based on the guidance torque command value set by the command value setting means;
When the steering angular speed detected by the steering speed detecting means is larger than the steering angular speed threshold set by the steering angular speed threshold setting means by a predetermined value or more, the guidance torque command value set by the command value setting means is reduced and corrected. Correction means to
And a control unit that controls the steering actuator based on a guidance torque command value corrected by the correction unit. The steering assist device according to claim 1, wherein the steering actuator is a steering assist motor of an electric power steering device.

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