JP2002308129A - Lane follow-up running control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To restrain and check a sudden change of steering torque in the case of fail during turning. SOLUTION: A radius of curvature ρ of a running lane is obtained from image information on the front of own vehicle imaged by a camera, and in a turning circuit where the radius of curvature ρis a designated value or less, a supply current limit value iL to a motor generating steering assist torque is set to a small designated value, and the motor supply current iM is made asymptotic to the set value. Although a driver has to give steering torque him/ herself to compensate for short steering torque, a sudden change of steering torque in fail can be restrained and prevented. The radius of curvature of the running lane can be calculated from the lateral acceleration, whereby when the camera is lost, the control is conducted by using the estimated radius of curvature.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lane-following traveling control device that detects a traveling lane and travels following the detected lane.

[0002]

2. Description of the Related Art Conventional lane-following traveling control devices include:
For example, one described in JP-A-7-104850 is known. In this conventional example, a lane mark such as a white line on a road is detected by a video camera or the like, a side position of the vehicle with respect to the lane mark is estimated by a signal processor, the direction of the vehicle is detected, and steering is performed based on these. By calculating the angle request and multiplying the deviation between the steering angle request and the detected steering angle value by the control gain, the difference is limited by the limiter, and further, the turning rate is limited and supplied to the electric motor coupled to the steering mechanism. , While generating control torque with an electric motor,
The steering mechanism is provided with a torque input that assists or opposes the steering torque from the driver, and cancels the torque input by the electric motor when the steering torque applied by the driver exceeds a predetermined torque threshold. A driver assistance system for a vehicle is described.

[0003]

In the above-described conventional lane-following traveling control device, when a failure occurs in the system, the supply current to the motor that generated the steering assist torque is stopped. There is a risk of significant change. Therefore, it is conceivable to detect the lateral acceleration generated in the vehicle and, when the lateral acceleration is large, restrict the current supplied to the motor that generates the steering assist torque to a small value.

However, the lateral acceleration is not necessarily generated only during turning, but is also generated due to, for example, a cross wind or a rut on a road surface. Therefore, a steering assist torque is generated even for a certain large lateral acceleration. As described above, the limit value of the supply current to the motor is set to be large. Therefore, the supply current supplied to the motor during the turning travel substantially reaches the maximum value or near the maximum value, and a sudden change in the steering torque at the time of failure is inevitable.

The present invention has been developed to solve these problems, and an object of the present invention is to provide a lane-following traveling control device in which the steering torque does not change suddenly during a failure during turning.

[0006]

In order to achieve the above object, according to the present invention, there is provided a lane-following traveling control device, comprising: a steering angle detecting means for detecting a steering angle; Image information detecting means for detecting an image; traveling lane information detecting means for detecting traveling lane information including at least the radius of curvature of the traveling lane from a road image ahead of the vehicle detected by the image information detecting means; Steering torque generating means for generating a steering torque according to the steering torque, and steering torque control means for outputting a supply current for generating a steering torque required to follow a traveling lane by the steering torque generating means, the steering torque The control means follows the travel lane based on at least the travel lane information detected by the travel lane information detection means and the steering angle detected by the steering angle detection means. Supply current calculation means for calculating a supply current for generating the steering torque required for the steering torque generation means, and the steering torque generation means based on the radius of curvature of the traveling lane detected by the traveling lane information detection means. And a supply current limit value setting means for setting the supply current limit value.

According to a second aspect of the present invention, there is provided a lane-following traveling control device according to the first aspect, wherein the supply current limit value setting means includes a traveling lane detected by the traveling lane information detecting means. When the radius of curvature is small, the limit value of the supply current is set small. According to a third aspect of the present invention, there is provided a lane-following traveling control device according to the second aspect, wherein the steering torque control means restricts the supply current calculated by the supply current calculation means to the supply current limit. Supply current asymptotic means for gradually increasing the supply current to the steering torque generating means by gradually approaching the supply current limit value set by the value setting means, wherein the supply current asymptotic means changes the supply current when decreasing the supply current. And the rate of change when the supply current is increased can be individually adjusted, and the rate of change when the supply current is decreased is set to be larger than the rate of change when the supply current is increased.

According to a fourth aspect of the present invention, a lane-following traveling control device according to the third aspect of the present invention further comprises a vehicle speed detecting means for detecting a traveling speed of the own vehicle, and the supply current asymptotic means comprises: When the traveling speed of the own vehicle detected by the vehicle speed detecting means is high, when the supply current is reduced and when the supply current is increased, the rate of change is increased.

According to a fifth aspect of the present invention, there is provided a lane-following traveling control device according to any one of the first to fourth inventions, wherein the supply current limit value setting means is arranged so that the traveling lane information detecting means determines the traveling lane. When the detection becomes impossible, the supply current limit value is held. According to a sixth aspect of the present invention, there is provided a lane-following traveling control device according to the first to fifth aspects, further comprising a lateral acceleration detecting means for detecting a lateral acceleration generated in the own vehicle, and controlling the steering torque control. The means includes a radius of curvature calculating means for calculating a radius of curvature of a traveling lane from at least the lateral acceleration detected by the lateral acceleration detecting means, and the supply current limit value setting means includes a step in which the traveling lane information detecting means determines a traveling lane. When the detection becomes impossible, a limit value of the supply current is set based on the curvature radius of the traveling lane calculated by the curvature radius calculation means.

According to a seventh aspect of the present invention, there is provided a lane-following traveling control device according to the sixth aspect of the present invention, wherein the curvature radius calculating means is configured such that the traveling lane information detecting means detects a traveling lane. An error between the curvature radius of the travel lane calculated from the lateral acceleration detected by the lateral acceleration detection means and the curvature radius of the travel lane detected is calculated.

The lane-following traveling control device according to claim 8 of the present invention is the vehicle according to claim 6 or 7, further comprising a vehicle speed detecting means for detecting a traveling speed of the host vehicle, and calculating the curvature radius. The means includes a low-pass filter that performs a low-pass filter process on the lateral acceleration detected by the lateral acceleration detection means, and the cutoff frequency of the low-pass filter decreases as the traveling speed of the vehicle detected by the vehicle speed detection means decreases. It is characterized in that it is set small.

According to a ninth aspect of the present invention, there is provided a lane-following traveling control device according to the first to eighth aspects, wherein the traveling lane information detecting means detects a lateral displacement of the own vehicle with respect to the traveling lane. A lateral displacement detecting means is provided, and the steering torque control means determines that the traveling lane-following traveling has deviated when the lateral displacement of the own vehicle with respect to the traveling lane detected by the lateral displacement detecting means becomes a predetermined value or more. A deviation determining unit that performs the traveling lane-following traveling when the supply current limit value setting unit sets a small limit value and the supply current to the steering torque generating unit is limited to a small value. The predetermined value of the lateral displacement for judging the deviation from is set to a small value.

According to a tenth aspect of the present invention, there is provided a lane-following traveling control apparatus according to the first to ninth aspects, wherein the steering torque control means sets the supply current limit value setting means to a small limit value. When the current supplied to the steering torque generating means is limited to a small value, a steering torque fluctuation adding means for changing the steering torque is provided.

[0014]

According to the lane-following travel control device according to the first aspect of the present invention, the steering required for following the travel lane based on the detected travel lane information and the steering angle. Calculate the supply current that generates the torque,
Since the configuration is such that the supply current limit value is set based on the detected radius of curvature of the traveling lane, if the supply current limit value is originally reduced in a traveling lane with a large steering torque and a small radius of curvature, steering during a failure A sudden change in torque can be suppressed and prevented.

According to the lane-following traveling control apparatus of the present invention, when the radius of curvature of the detected lane is small, the limit value of the supply current is set to be small. Sudden change in the steering torque of the vehicle can be prevented. According to the lane-following traveling control device according to claim 3 of the present invention, the calculated supply current gradually approaches the limit value, and the rate of change when the supply current decreases and the supply current increases. And the rate of change are individually adjustable, and the rate of change when the supply current is decreased is set to be larger than the rate of change when the supply current is increased. It is possible to rapidly reduce the steering torque and prepare for a sudden change in the steering torque at the time of a failure, and it is possible to prevent or suppress the fluctuation of the steering torque in the traveling lane where the turning is repeated alternately.

Further, according to the lane-following traveling control device of the present invention, when the detected traveling speed of the own vehicle is high, when the supply current is decreased and when the supplied current is increased, the rate of change is increased. This makes it possible to keep the distance required for the change of the supply current constant or almost constant, so that in a certain place, the supply current value is equal at a certain position regardless of the running speed of the host vehicle. Or it can be made substantially equivalent.

Further, according to the lane-following traveling control device of the present invention, when the traveling lane cannot be detected, the supply current limit value is held.
Variations in steering torque when the traveling lane is detected again can be prevented. According to the lane-following travel control device according to claim 6 of the present invention, the curvature radius of the travel lane is calculated from the detected lateral acceleration, and the travel lane calculated when the travel lane cannot be detected. Because the supply current limit value is set based on the radius of curvature, it is possible to prevent a sudden change in the steering torque at the time of a failure even when the traveling lane cannot be detected.

According to the lane-following travel control device of the present invention, when the travel lane is detected, the curvature radius of the travel lane calculated from the detected lateral acceleration is detected. Because it is configured to calculate the error from the radius of curvature of the traveling lane, it is possible to more accurately calculate the radius of curvature of the traveling lane when the traveling lane can no longer be detected, and it is possible to calculate the failure radius when the traveling lane cannot be detected. A sudden change in the steering torque can be more reliably suppressed and prevented.

Further, according to the lane-following traveling control device of the present invention, a low-pass filter for low-pass filtering the detected lateral acceleration is provided.
Since the cutoff frequency of the low-pass filter is set to be smaller as the detected traveling speed of the host vehicle is lower, the lateral acceleration on the low frequency side is extracted during low-speed traveling when the degree of freedom of steering by the driver is high. The calculation accuracy of the radius of curvature of the traveling lane can be improved based on the lateral acceleration.

According to the lane-following traveling control device of the ninth aspect of the present invention, the traveling lane-following traveling deviates when the detected lateral displacement of the host vehicle with respect to the traveling lane becomes a predetermined value or more. And a small limit value is set for the supply current, and when the supply current is limited to a small value, the predetermined value of the lateral displacement for determining the deviation of the traveling lane following travel is set to be small. It is possible to make the driver recognize early that the steering lane departs due to the lack of the steering torque, and thus the driver can expect a positive steering torque.

According to the lane-following traveling control device of the present invention, when the supply current is set to a small limit value and the supply current is limited to a small value, the fluctuation of the steering torque can be reduced. Is provided, the driver can recognize at an early stage that the steering torque is insufficient, so that a positive steering torque by the driver can be expected.

[0022]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic configuration diagram showing a first embodiment of the present invention. In FIG. 1B, 1FL, 1F
R indicates a front wheel, 1RL and 1RR indicate a rear wheel, and a front wheel 1F.
The L, 1FR is provided with a general rack and pinion type steering mechanism. This steering mechanism includes front wheels 1FL,
Rack 2 connected to 1FR steering shaft (tie rod)
And a pinion 3 that meshes with the pinion 3 and a steering shaft 5 that rotates the pinion 3 with a steering torque given to the steering wheel 4.

An automatic steering mechanism 1 which constitutes a steering actuator for automatically steering the front wheels 1FL, 1FR is provided above the pinion 3 in the steering shaft 5.
3 are provided. The automatic steering mechanism 13 includes a driven gear 1 mounted coaxially with the steering shaft 5.
4, a drive gear 15 meshing with the drive gear 4, and an automatic steering motor 16 for driving the drive gear 15 to rotate. Note that a clutch mechanism 17 is interposed between the automatic steering motor 16 and the drive gear 15, and the clutch mechanism 17 is engaged only during automatic steering control. Otherwise, the clutch mechanism 17 is in an unengaged state. The rotation force of the automatic steering motor 16 is prevented from being input to the steering shaft 5.

Various sensors are mounted on the vehicle. In the figure, reference numeral 21 denotes a steering angle sensor which detects a steering angle θ from the rotation angle of the steering shaft 5 and outputs the detected steering angle θ to the control unit 10. A vehicle speed sensor 22 is attached to the output side of an automatic transmission (not shown), and a vehicle speed detection value V detected by the vehicle speed sensor 22 is also output to the control unit 10. Further, the vehicle is provided with a lateral acceleration sensor 23 as a lateral acceleration detecting means for detecting a lateral acceleration generated in the vehicle.
The lateral acceleration G _Y detected in 3 is also the control unit 1
Output to 0. Here, the steering angle θ output from the steering angle sensor 21 is a positive value during right steering, as shown in FIG.
Is set to be a negative value when the leftward steering, lateral acceleration G _Y output from the lateral acceleration sensor 23, as shown in FIG. 2, set to be a negative value positive value, when the right turning during left turning Have been.

Further, as shown in FIG. 1A, a monocular camera 25 such as a CCD camera is installed on a fixed portion such as an inner mirror stay in the vehicle compartment, and captures a situation in front of the vehicle. 26. This camera controller 26 is, for example, disclosed in
As described in JP-A-102499, a white line near the own vehicle is detected by a process such as binarization of the image data of the monocular camera 25, and the own vehicle with respect to the running lane at a predetermined vehicle forward fixation point is detected. The relative lateral displacement y, the yaw angle Φ with respect to the tangent to the white line of the vehicle, and the radius of curvature ρ ahead of the traveling lane are calculated and output to the control unit 10.
It should be noted that the relative lateral displacement of the host vehicle with respect to the traveling lane indicates, for example, how the host vehicle deviates in the lateral direction with respect to the center of the traveling lane.

The control unit 10 is constituted by a discretized digital system such as a microcomputer (not shown), and receives the input yaw angle Φ, relative lateral displacement y,
An optimum target steering angle θ ^* is calculated when the vehicle passes through a curve based on the road curvature ρ, and the automatic steering motor 16 is adjusted so that the actual steering angle θ detected by the steering angle sensor 21 matches the target steering angle θ ^*. It calculates a supply current i _M for, by outputting the supply current i _M from the current limiting process to a pulse width modulation automatic steering motor 16 is converted into a pulse current, duty automatic steering motor 16 Control.

Next, the operation of the above embodiment will be described with reference to the flowchart of FIG. This steering control process is executed as a timer interrupt process for each predetermined sampling time (for example, 10 msec.). First, in step S1,
The camera controller 26 determines whether or not the traveling lane, specifically, the white lane, has been lost (lost), that is, has not been detected. If the traveling lane has been lost, the process proceeds to step S2. Shifts to step S3.

In step S3, the actual steering angle θ detected by the steering angle sensor 21, the lateral acceleration G _Y detected by the lateral acceleration sensor 23, the detected vehicle speed V detected by the vehicle speed sensor 18, and the detected by the camera controller 26. After reading the yaw angle Φ, the relative lateral deviation y and the travel lane curvature radius ρ, the process proceeds to step S4. In the step S4, based on the yaw angle Φ, the relative lateral displacement y and the running lane curvature radius ρ read in the step S3, a current target steering angle θ ^* (n) is calculated according to the following equation: The previous target steering angle θ ^* (n-1) stored in the current target steering angle storage area is updated and stored in the previous target steering angle storage area, and the current target steering angle θ ^* (n) is stored in the current target steering angle storage area. After the update storage in the corner storage area, the process proceeds to step S5.

Θ ^* = Ka · Φ + Kb · y + Kc / ρ (1) where Ka, Kb, and Kc are control gains that vary according to the vehicle speed, and the target steering angle θ ^* is steering in the right direction. At times, the value is a positive value, and when steering in the left direction, the value is a negative value. Step S5
Then, according to the following two equations, the actual steering angle θ is changed to the target steering angle θ ^*.
The automatic steering motor 16
_Is calculated and stored in the reference motor supply current storage area after updating the reference motor supply current i _M0.
Move to 6.

I _M0 = Kvi (Kp + Ki / s + Kd · s) · (θ ^* −θ) (2) where Kvi is a control gain for converting a voltage value to a current value, and Kp is a proportional gain. , Ki are integral gains, Kd is a differential gain, and s is a Laplace operator. The reason for calculating the reference motor supply current i _M0 by these two equations is that, as shown in FIG. 4, the subtractor 31 subtracts the actual steering angle θ from the target steering angle θ ^* to calculate the difference Δθ between them. This is supplied to a computing unit 32 to perform a PID control calculation to obtain a target motor control voltage V
^* , The target motor control voltage V ^* is supplied to the voltage-current converter 33, and the target motor control voltage V ^* is multiplied by the control gain Kvi to calculate the motor supply current i _M , which is automatically steered. Considering the case where a feedback control system for supplying to the motor 16 is configured, an operation equivalent to this is performed.

In step S6, step S3
Based on the travel lane curvature radius ρ read in step (1), the motor supply current limit value i _L is set according to the control map shown in FIG. 5, and the process proceeds to step S7. Control map of FIG. 5, for example, set to ₁ and 1100m about the predetermined value [rho set to about 1000m as the radius of curvature of the traffic lane with a predetermined value [rho ₂ a hysteresis, lane curvature radius [rho small relatively large and a predetermined value i _Hi constant, relatively small predetermined value i _Lo constant supply current limit i _L at a predetermined value [rho ₁ below region a supply current limit i _L at a predetermined value [rho ₁ or more regions when made And When the reverse to the traveling lane curvature radius [rho increases the supply current limit i _L relatively great predetermined value i _Hi constant at a predetermined value [rho ₂ or more regions, the supply current limit i _L at a predetermined value [rho ₂ below regions Is a relatively small predetermined value i
_{Lo is} fixed.

At the step S7, at the step S6
Motor supply current limit value i set by_LIs relatively small
The predetermined value i_LoIs determined, and the motor supply
Current limit value i_LIs a predetermined value i_LoIf step S
8; otherwise, proceed to step S9.
You. In step S8, the last sampling time
Set motor supply current i _MFrom step S6
Set motor supply current limit value i_LAbsolute value of the value after subtracting |
i_M−i_LIs a relatively small predetermined value Δi
₀It is determined whether the current is less than or equal to
_MFrom the motor supply current limit value i_LAbsolute value of the value after subtracting |
i_M−i_L| Is the predetermined value Δi₀Step if
The process moves to step S11, otherwise, step S10
Move to

At step S9, at step S5
The absolute value | i _M0 −i _M | of the value obtained by subtracting the motor supply current i _M set at the previous sampling time from the reference motor supply current i _M0 calculated in the above is equal to or less than the relatively small predetermined value Δi _0. step if is less than a predetermined value .DELTA.i ₀ | determines whether a, the absolute value of the reference motor current supplied from the i _M0 previous motor supply current i a value obtained by subtracting the _M | i _M0 -i _M The process proceeds to S11, and if not, the process proceeds to step S10.

In step S10, the motor supply current i _M set at the previous sampling time is gradually approached to the motor supply current limit value i _L with a constant gradient, and this is set as a new motor supply current i _M command value. Then, the process proceeds to step S11. On the other hand, in step S2, the motor supply current i _M and the motor supply current limit value i _L are held at the previous values, and then the process proceeds to step S11.

In step S11, the set motor supply current i _M is output to the motor 16 as a command value, and then the process returns to the main program. FIG. 6 is a timing chart of the motor supply current by the calculation processing of FIG. It should be noted that the traveling lane information in the drawing indicates “1” to indicate traveling lane detection and “0” to indicate no traveling lane detection.

[0036] Here, running from the state of curvature radius [rho is traveling the relatively small predetermined value [rho ₁ or more driving lane, the time t ₀₁ after, the predetermined value [rho ₁ following the radius of curvature of the traffic lane , then the time t ₀₅ after, proceeds to the larger predetermined value [rho ₂ or more the radius of curvature of the traffic lane. Also,
Until time t ₀₅ from the time t ₀₁ is, from the time t ₀₃ to time t _04, and in the time t ₀₅ after, from the time t ₀₆ to time t _07, have lost sight of the driving lane by the camera 25.

In this timing chart, the time t
To _01, the motor supply current limit i _L is a relatively large predetermined value i _Hi, a relatively small predetermined value i _Lo from time t ₀₁ to time t _05, the time t ₀₅ after again at a predetermined value i _Hi is there. The relatively large predetermined value i _Hi is a large current value that can cover almost the entire region of the necessary steering assist torque, and the relatively small predetermined value i _Lo is conversely a failure occurs and the supply current stops. The current value is small enough that the steering torque does not suddenly change even if it is performed.

[0038] Therefore, until the time t _01, the reference motor supply current i _M0 calculated according to the radius of curvature ρ of the traffic lane at step S5 in processing of FIG. 3 is output as a motor supply current i _M intact . Meanwhile, since the motor supply current limit i _L is switched to a relatively small predetermined value i _Lo at time t _01, the time t ₀₁ after, the process proceeds to step S10 through step S8 from step S7 of the arithmetic processing of Fig. 3 The flow is repeated, and as a result, the motor supply current i _M gradually approaches the limit value i _L (= i _Lo ) with a constant slope, and when the motor supply current i _M matches or almost matches the limit value i _L at time t ₀₂ ,
Since the flow is switched from step S8 to step S11 in the calculation processing in FIG. 3, the motor supply current i _M is thereafter kept at the limit value i _{L including the} relatively small predetermined value i _Lo . Thereafter, from time t ₀₃ to time t ₀₄
However, in this case, the process shifts from step S1 to step S2 of the calculation processing in FIG. 3 and the motor supply current i _M and the motor supply current limit value i _{L up to that point.}
, The motor supply current i _M is also kept at the limit value i _L (= i _Lo ).

The fact that the motor supply current i _M is held at the relatively small limit value i _L (= i _Lo ) means that
The steering assist torque is insufficient. Therefore, the driver has to steer the steering wheel by himself, but the steering torque does not change suddenly even if a failure occurs. Since the time t ₀₅ in lane curvature radius [rho motor supply current limit i _L from becoming a predetermined value [rho ₂ or is switched to a relatively large predetermined value i _Hi, the time t ₀₅ after, Figure The flow from step S7 of step 3 to step S10 via step 9 is repeated, and as a result, the motor supply current i _M approaches the limit value i _L (= i _Hi ) with a constant slope. . However, during which time, in order to lose sight of the driving lane from the time t ₀₆ to time t _07,
The motor supply current i _{M at} time t ₀₆ is held until time t ₀₇ . Of course, during that time, the motor supply current limit value i _L is kept at the relatively large predetermined value i _Hi . Then, at time t ₀₇
When the traveling lane is detected again, the motor supply current i _M is asymptotic toward the limit value i _L (= i _Hi ) with a constant slope. Eventually, the increased motor supply current i _M is used as the reference motor supply current i _M0 calculated in step S5 of the calculation processing in FIG.
When it is almost or almost the same, the flow is switched to the flow that shifts from step S9 to step S11 in the calculation processing in FIG. 3, and thereafter, the reference motor supply current i _M0 calculated according to the radius of curvature ρ of the traveling lane becomes _smaller. It is output as it is as the motor supply current i _M.

As described above, in the lane-following traveling control device of this embodiment, when the detected curvature radius ρ of the traveling lane is smaller than the predetermined value ρ ₁ or the predetermined value ρ ₂ , the motor supply current limit value i _L is compared. Since the predetermined value i _Lo is set to a very small value, it is possible to prevent a sudden change in the steering torque at the time of a failure. Further, according to the lane following distance control device of this embodiment, since a configuration for holding the motor supply current limit i _L when it becomes impossible to detect the traffic lane, the variation of the steering torque when the driving lane is detected again Can be suppressed.

As described above, the steering angle sensor 21 and FIG.
3 constitutes a steering angle detecting means of the present invention. Similarly, the monocular camera 25 constitutes an image information detecting means, and the camera controller 26 and FIG.
Step S3 of the arithmetic processing of the above constitutes the traveling lane information detecting means, the motor 16 constitutes the steering torque generating means,
3 and the control unit 10
Constitute the steering torque control means, steps S4 and S5 of the calculation processing of FIG. 3 constitute supply current calculation means, and step S6 of the computation processing of FIG. 3 constitute supply current limit value setting means.

Next, a description will be given of a second embodiment of the lane-following traveling control device according to the present invention. The vehicle configuration of this embodiment is the same as that of FIG. 1 of the first embodiment, and the arithmetic processing performed by the control unit 10 is changed from that of FIG. 3 of the first embodiment to that of FIG. Have been. 7 is also performed by a timer interrupt every predetermined sampling time ΔT, as in the first embodiment. First, in step S21, the camera controller 26 loses track of the traveling lane, specifically, the white lane. Is determined (ie, lost), that is, whether or not detection is no longer possible. If the traveling lane has been lost, the process proceeds to step S22,
If not, the process proceeds to step S23.

In step S23, the actual steering angle θ detected by the steering angle sensor 21, the lateral acceleration G _Y detected by the lateral acceleration sensor 23, the detected vehicle speed V detected by the vehicle speed sensor 18, and the detected by the camera controller 26. After reading the yaw angle Φ, the relative lateral deviation y and the travel lane curvature radius ρ, the process proceeds to step S24. In step S24, the vehicle speed V and the travel lane curvature radius ρ are obtained from the control map of FIG.
Cut-off frequency F _{C-OFF of} low-pass filter according to
Is set, and the process proceeds to step S25. The control map shown in FIG. 8 has the horizontal axis representing the vehicle speed V, the vertical axis representing the cutoff frequency F _C-OFF of the low-pass filter, and the traveling lane curvature radius ρ as a parameter. As the vehicle speed V increases, the traveling lane curvature radius increases. The lower the value of ρ, the lower the cutoff frequency F _C-OFF of the low _- pass filter.

In the step S25, the step S
The lateral acceleration G _Y read in 23, wherein the step S
After performing the low _- pass filter processing at the cutoff frequency F _C-OFF set in 24, the process proceeds to step S26. This low-pass filter processing removes noise components due to crosswinds, ruts, modified steering, and the like. Step S26
Now, the low-pass filtered lateral acceleration G _Y-LPF
From the vehicle speed V read in step S23 and the estimated radius of curvature ρＳ in accordance with the following three equations, and then proceeds to step S2.
Move to 7.

Ρ ＾ = k · V ² / G _Y-LPF (3) Note that the correction coefficient k in the equation is a record of the detected radius of curvature ρ of the traveling lane and the calculated estimated radius of curvature ρ ＾. It is determined by the least squares method. In step S27, the radius of curvature error Δρ is calculated by subtracting the estimated radius of curvature ρ ＾ calculated in step S26 from the radius of curvature ρ of the traveling lane read in step S23, and then the process proceeds to step S28.

In the step S28, similarly to the first embodiment, the present yaw angle Φ, the relative lateral displacement y and the travel lane curvature radius ρ read in the step S23 are used in accordance with the above equation (1). Calculate the target steering angle θ ^* (n),
The previous target steering angle θ ^* (n-1) stored in the current target steering angle storage area is updated and stored in the previous target steering angle storage area, and the current target steering angle θ ^* (n) is stored in the current target steering angle storage area. After the update storage in the corner storage area, the process proceeds to step S29.

In step S29, similarly to the first embodiment, the reference motor supply current i to the automatic steering motor 16 is obtained by PID control according to the above equation (2) so that the actual steering angle θ matches the target steering angle θ ^*. _M0 is calculated, updated and stored in the reference motor supply current storage area, and then the process proceeds to step S30. In step S30, as in the first embodiment, based on the traveling lane curvature radius ρ read in step S23, the motor supply current limit value i _L is set according to the control map of FIG. Move to step S31.

In step S22, the actual steering angle θ detected by the steering angle sensor 21 and the lateral acceleration sensor 2
After the lateral acceleration G _X detected in step 3 and the vehicle speed detection value V detected by the vehicle speed sensor 18 are read, the process proceeds to step S32. In step S32, the cutoff frequency F _C of the low-pass filter according to the vehicle speed V, the traveling lane curvature radius ρ read at the previous sampling time, or the estimated curvature radius ρ ＾ calculated at the previous sampling time, from the control map of FIG. After setting _-OFF , the process _proceeds to step S33.

At the step S33, at the step S33
The lateral acceleration G _Y read in 22, wherein the step S
After performing the low _- pass filter processing at the cutoff frequency F _C-OFF set in S32, the process proceeds to step S34. In step S34, an estimated radius of curvature ρ ＾ is calculated from the low-pass-filtered lateral acceleration G _Y-LPF and the vehicle speed V read in step S22 according to the following equation (4), and then the process proceeds to step S35.

Ρ ＾ = kV ² / G _Y-LPF + Δρ (4) In step S35, the reference motor supply current i _M0 calculated at the previous sampling time or held at the previous sampling time. And then step S
Move to 36. In the step S36, based on the calculated estimated radius of curvature [rho ^ in step S34, according to the control map of FIG. 5, the motor supply current limit i _L
Is set, and then the flow shifts to the step S31.

At the step S31, at the step S31
It is determined whether or not the motor supply current limit value i _L set in step 30 or step S36 is the relatively small predetermined value i _Lo . If the motor supply current limit value i _L is the predetermined value i _Lo , Shifts to step S37, and if not, shifts to step S38. In the step S38, the motor supply current change rate Hi corresponding to the vehicle speed V is set based on the control map of FIG.
Move to This control map is configured such that the motor supply current change rate Hi linearly increases as the vehicle speed V increases. The gradient of the motor supply current change rate Hi is relatively small.

In step S37, the motor supply current change rate Hi corresponding to the vehicle speed V is set based on the control map shown in FIG. 9B, and then the flow shifts to step S39. This control map is configured such that the motor supply current change rate Hi decreases linearly as the vehicle speed V increases. Note that the gradient of the motor supply current change rate Hi is relatively large.

At the step S39, at the step S39
It is determined whether or not the motor supply current limit value i _L set in step 30 or step S36 is the relatively small predetermined value i _Lo . If the motor supply current limit value i _L is the predetermined value i _Lo , Shifts to step S40, and if not, shifts to step S41. In step S40, the absolute value | i of a value obtained by subtracting the motor supply current limit value i _L set in step S30 or step S36 from the motor supply current i _M set at the previous sampling time.
_M− i _L | is a relatively small predetermined value Δi ₀ set in advance.
To determine a whether or less, a previous motor supply current i _M
The absolute value of the value obtained by subtracting the motor supply current limit i _L from | i
_{If M−} i _L | is equal to or smaller than the predetermined value Δi ₀ , the process shifts to step S43; otherwise, the process shifts to step S42.

At the step S41, at the step S41
The absolute value | i _M0 −i _M | of the value obtained by subtracting the motor supply current i _M set at the previous sampling time from the reference motor supply current i _M0 calculated in 29 is the relatively small predetermined value Δi _0. wherein if is less than a predetermined value .DELTA.i ₀ | determines whether the whether or less, the absolute value of the reference motor current supplied from the i _M0 previous motor supply current i a value obtained by subtracting the _M | i _M0 -i _M The process proceeds to step S43, and if not, the process proceeds to step S42.

In step S42, the motor supply current i _M set at the previous sampling time is changed to the rate of change Hi set in step S37 or S38.
To ascend to the motor supply current limit value i _L , make it a new command value of the motor supply current i _M , and then proceed to step S43. In the step S43, the steps S30 or motor supply current limit i _L set in step S36, it is determined whether the relatively small predetermined value i _Lo, the motor supply current limit i _L is predetermined If the value is i _Lo , the process proceeds to step S44; otherwise, the process proceeds to step S45.

In step S44, the lateral displacement threshold value y _L for determining lane following deviation is set to a relatively small predetermined value y.
_After setting to _LLo , the _{process proceeds} to step S46. In the step S46, an assist torque variation signal is added to the motor supply current, and the process proceeds to step S47. The assist torque fluctuation signal is obtained by, for example, vibrating the steering wheel or changing the motor supply current during asymptote in a stepwise manner, so that the motor supply current limit value i _L is a predetermined value i _Lo . That is, the driver is made to recognize that the steering assist torque tends to be insufficient.

On the other hand, in step S45, the vehicle follows the lane.
Lateral displacement threshold y for determining deviation _LA relatively large place
Fixed value y_LHiAnd then proceed to step S47.
You. In step S47, the read in step S23 is performed.
The absolute value of the relative lateral displacement | y |_L
The absolute value of the relative lateral displacement |
y | is the lateral displacement threshold y_LIf so, step S4
8; otherwise, go to step S49.
I do.

In step S48, an alarm command is output to an alarm device (not shown), and the flow advances to step S49. In step S49, the set motor supply current i _M is output to the motor 16 as a command value, and then the process returns to the main program. In this calculation process, when the traveling lane is not lost, the estimated curvature radius ρ ＾ is calculated from the low-pass filtered lateral acceleration G _Y-LPF and compared with the traveling lane curvature radius ρ obtained from the image information. To calculate the correction coefficient k and the error Δρ. Usually, there is often a steady-state error such as a drift component between the detected lateral acceleration and the radius of curvature calculated therefrom. This error is obtained by comparing with the traveling lane curvature radius ρ obtained from the image information, and when the traveling lane is lost, a more accurate estimated curvature radius ρ ＾ is calculated using the curvature radius error Δρ and the correction coefficient k. It becomes possible.

In this calculation process, the lateral acceleration G
Cutoff frequency F _{C-OFF of} low-pass filter applied to _Y
Is set smaller as the vehicle speed V is smaller or the traveling lane curvature radius ρ is larger, that is, only the lower frequency lateral acceleration G _Y is extracted. In general, the lower the vehicle speed V or the larger the radius of curvature ρ of the traveling lane, the greater the degree of freedom of the steering by the driver, that is, the more easily the driver fluctuates or applies a corrected rudder. Then, a change occurs in the lateral acceleration G _Y , and it is difficult to calculate an accurate estimated radius of curvature ρ ＾. Therefore, in the present embodiment, the cutoff frequency F _C-OFF of the low _- pass filter is set smaller as the vehicle speed V is smaller or the traveling lane curvature radius ρ is larger, so that the lower frequency lateral acceleration G _Y , that is, Only the lateral acceleration having no component due to the corrected steering is extracted, and the estimated radius of curvature ρ ＾ can be calculated more accurately based on the low-pass filtered lateral acceleration G _Y-LPF .

Of course, even when the vehicle is lost in this manner, the motor supply current limit value i _L is set based on the calculated estimated radius of curvature ρ ＾. Fluctuation becomes small. Further, in this calculation processing, it is determined whether the motor supply current limit value i _L is the relatively small predetermined value i _Lo, that is, whether the motor supply current limit value i _L is the predetermined value i _Lo or the predetermined value i _Hi. The motor supply current change rate H depending on the vehicle speed V
i is set. Specifically, when the motor supply current limit value i _L is the relatively small predetermined value i _Lo , a larger decrease gradient Hi is set for the same vehicle speed V, and the motor supply current limit value i _L is set. _{When L} is the relatively large predetermined value i _Hi , a smaller increase gradient Hi is set for the same vehicle speed V.

First, with respect to the vehicle speed V, in a curve at the same place, since the radius of curvature ρ is constant, the motor supply current limit value i _L is always set to the same value. If the rate of change that causes the motor supply current i _M to gradually approach the limit value i _L is constant, the traveling distance until the motor supply current i _M matches or almost matches the limit value i _L according to the vehicle speed V. Different, that is, the position changes. Conversely, if the change rate Hi is increased as the vehicle speed V increases, the travel distance until the motor supply current i _M matches or almost matches the limit value i _L can be made equal, that is, the position can be made the same. It becomes possible. Therefore, it is possible to always perform the same steering torque change at the same position regardless of the vehicle speed V on the same curve at the same place, so that it is possible to prevent a driver traveling in the same place from feeling uncomfortable. It becomes possible.

When the motor supply current limit value i _L is the relatively small predetermined value i _Lo , a larger decreasing rate of change Hi is set for the same vehicle speed V, that is, the steering torque is insufficient. At times, the steering torque can be reduced quickly to prepare for a sudden change in the steering torque during a failure. When the motor supply current limit value i _L is the relatively large predetermined value i _Hi , a smaller change rate Hi of the increasing slope is set for the same vehicle speed V, that is, slowly when the steering torque is increased. By changing the steering torque, it is possible to prevent the fluctuation of the steering torque in the traveling lane in which the turning is alternately repeated.

In this calculation process, when the motor supply current limit value i _L is the relatively small predetermined value i _Lo ,
That is, when the steering torque is insufficient, a relatively small predetermined value y _LLo is set as a lateral displacement threshold value y _L for determining lane-following traveling deviation. This is for generating an alarm in step S48 when the absolute value | y | of the detected relative lateral displacement is equal to or greater than the lateral displacement threshold y _L in step S47 of the arithmetic processing in FIG. Things. As described above, when the steering torque is insufficient, the driver needs to apply the steering torque by himself / herself, or the driver may deviate from the traveling lane. Therefore, in this embodiment, when to insufficient steering torque, a smaller value of the lateral displacement threshold y _L for determining the lane keeping running deviation, so as to recognize the driver in promptly alert when deviating likely I have.

In this calculation process, when the motor supply current limit value i _L is the relatively small predetermined value i _Lo ,
That is, when the steering torque is insufficient, an assist torque variation signal is added to the motor supply current.
As described above, the steering wheel is vibrated or the steering torque is reduced stepwise, so that the driver can quickly determine that the steering torque is reduced, that is, the steering torque is insufficient. Can be recognized.

FIG. 10 is a timing chart of the motor supply current by the calculation processing of FIG. It should be noted that the traveling lane information in the drawing indicates “1” to indicate traveling lane detection and “0” to indicate no traveling lane detection. Here, the state in which the curvature radius [rho is traveling the relatively small predetermined value [rho ₁ or more driving lane, the time t ₂₁ after travels the predetermined value [rho ₁ following the radius of curvature of the traffic lane, then time t ₂₅ after, proceeds to the larger predetermined value [rho ₂ or more the radius of curvature of the traffic lane. Also, until time t ₂₅ from the time t _21, from the time t ₂₃ to the time t _24, and in the time t ₂₅ since, from the time t ₂₆ to time t _27, which lost the driving lane by the camera 25 .

In this timing chart, the time t
Until ₂₁ , the motor supply current limit value i _L is a relatively large predetermined value i _Hi , a relatively small predetermined value i _Lo from time t ₂₁ to time t ₂₅ , and after time t ₂₅ , the motor supply current limit value i _L is again a predetermined value i _Hi . is there. As described above, the relatively large predetermined value i _Hi is a large current value that can cover almost the entire region of the necessary steering assist torque, and conversely, the relatively small predetermined value i _Lo
Is a small current value such that the steering torque does not suddenly change even if a failure occurs and the supply current is stopped.

[0067] Therefore, until the time t _21, the 7 reference motor supply current i _M0 calculated according to the radius of curvature ρ of the traffic lane in step S29 of the arithmetic processing is outputted as a motor supply current i _M intact . Meanwhile, since the motor supply current limit i _L is switched to a relatively small predetermined value i _Lo at time t _21, step through the time t ₂₁ after the step S40 from the step S39 of the arithmetic processing of Fig. 7 S4
2 is repeated, and as a result, the motor supply current i _M changes at the rate of change Hi set in step S37.
In Yuki it is asymptotic to limit i _L (= i _Lo), match or when substantially matches the limit value i _L at time t _22, since it is switched to the flow moves from step S41 in the arithmetic processing of Fig. 7 to step S43 , And thereafter, the motor supply current i _M
Is held at a limit value i _L consisting of a relatively small predetermined value i _Lo . Thereafter, missing the traffic lane from the time t ₂₃ to the time t _24, and proceeds to S22 after step from the step S21 of the arithmetic processing of FIG. 7 in that case, the motor supply current limit corresponding to the estimated radius of curvature [rho ^ The value i _L , that is, the relatively small predetermined value i _Lo continues to be set.

The fact that the motor supply current i _M is held at the relatively small limit value i _L (= i _Lo ) means that
The steering assist torque is insufficient. Therefore, the driver has to steer the steering wheel by himself, but the steering torque does not change suddenly even if a failure occurs. Since the time t ₂₅ in lane curvature radius [rho motor supply current limit i _L from becoming a predetermined value [rho ₂ or is switched to a relatively large predetermined value i _Hi, the time t ₂₅ after, Figure 7 is repeated from step S39 to step S42 via step S41. As a result, the motor supply current i _M is limited to the limit value i _L (= i _Hi at the rate of change Hi set in step S38). )
It is asymptotic toward. Meanwhile, the time from the time t ₂₆ t
To ₂₇ missing the traffic lane, but continue to set the motor supply current limit i _L based on the estimated radius of curvature [rho ^ calculated in the same manner as described above to a relatively large predetermined value i _Hi, the motor supply current i _M also during It keeps asymptotic toward the limit value i _L (= i _Hi ) at the change rate Hi.

The traveling lane was detected again at time t ₂₇ , but at that time, the motor supply current i _M did not match the reference motor supply current i _M0, and the motor supply current increased at time t _28. When the current i _M matches or almost matches the reference motor supply current i _M0 calculated in step S29 of the calculation processing of FIG. 7, step S41 of the calculation processing of FIG.
Is switched to the flow from step to step S43, and thereafter, the reference motor supply current i _M0 calculated according to the radius of curvature ρ of the traveling lane is output as it is as the motor supply current i _M.

As described above, in the lane-following traveling control device of this embodiment, when the detected curvature radius ρ of the traveling lane is smaller than the predetermined value ρ ₁ or the predetermined value ρ ₂ , the motor supply current limit value i _L is compared. Since the predetermined value i _Lo is set to a very small value, it is possible to prevent a sudden change in the steering torque at the time of a failure. As described above, the steering angle sensor 21 and steps S23 and S22 of the calculation processing in FIG. 7 constitute a steering angle detecting means of the present invention, and similarly, the monocular camera 25 constitutes an image information detecting means, and The camera controller 26 and step S23 of the arithmetic processing of FIG. 7 constitute a traveling lane information detecting means, the motor 16 constitutes a steering torque generating means, and the entire arithmetic processing of FIG. 7 and the control unit 10 constitute a steering torque control means. And steps S28 and S2 of the arithmetic processing of FIG.
9 constitutes supply current calculation means, steps S30 and S36 of the calculation processing of FIG. 7 constitute supply current limit value setting means, and steps S31, S37, S38 and S42 of the calculation processing of FIG. The supply current asymptotic means is constituted, the wheel speed sensor 22 and steps S22 and S23 of the calculation processing of FIG. 7 constitute vehicle speed detection means, and the lateral acceleration sensor 23 and steps S22 and S23 of the calculation processing of FIG. Constitutes a lateral acceleration detecting means, and steps S32 to S34 of the arithmetic processing of FIG. 7 constitute a radius of curvature calculating means, and the camera controller 26 and step S23 of the arithmetic processing of FIG.
Constitute the lateral displacement detecting means, steps S43, S44, and S47 of the arithmetic processing in FIG. 7 constitute the deviation determining means, and step S46 of the arithmetic processing in FIG. 7 constitutes the steering torque fluctuation adding means. .

In the above embodiment, the target steering angle θ ^*
Has been described based on the yaw angle Φ, the relative lateral deviation y and the road curvature radius ρ, but the present invention is not limited to this. The target is calculated based on the relative lateral deviation y and the road curvature radius ρ. The steering angle θ ^* may be calculated, and further, the target steering angle θ ^* may be calculated based on the vehicle speed V and the road curvature radius ρ ^.
Or the current steering position may be grasped by using the GPS function, and the target steering angle θ ^* may be calculated by calculating the road curvature radius ρ from the map information of the navigation system.

Further, in the above-described embodiment, the arithmetic processing of the control unit is performed by the microcomputer. However, instead of this, various theoretical circuits may be combined.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing an embodiment of a lane-following traveling control device of the present invention.

FIG. 2 is an explanatory diagram illustrating a control steering direction and a lateral acceleration direction.

FIG. 3 is a flowchart illustrating a first embodiment of a calculation process for lane-following traveling control.

FIG. 4 is a block diagram illustrating an example of a steering servo system.

FIG. 5 is a control map for setting a supply current limit value.

FIG. 6 is a timing chart according to the calculation processing of FIG. 3;

FIG. 7 is a flowchart illustrating a second embodiment of a calculation process for lane-following traveling control.

FIG. 8 is a control map for setting a cutoff frequency of a low-pass filter.

FIG. 9 is a control map for setting a supply current change rate.

FIG. 10 is a timing chart according to the calculation processing of FIG. 3;

[Explanation of symbols]

 2 is a rack 3 is a pinion 4 is a steering wheel 5 is a steering shaft 10 is a control unit 13 is a steering mechanism 16 is an automatic steering motor 21 is a steering angle sensor 22 is a vehicle speed sensor 23 is a lateral acceleration sensor 25 is a monocular camera 26 is a camera controller

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G08G 1/16 G08G 1/16 C 5H301 // B62D 101: 00 B62D 101: 00 111: 00 111: 00 113 : 00 113: 00 F term (reference) 3D032 CC03 CC08 CC32 CC39 CC46 DA03 DA23 DA24 DA27 DA29 DA32 DA84 DA88 DC01 DC02 DC03 DC07 DC08 DC09 DC12 DC21 DC29 DC33 DC34 DD02 DD05 DD10 DD17 DE03 DE05 DE08 EA01 EB11 EC23 EC24 GG01 3D033 CA13 CA17 CA21 CA31 CA33 3D044 AA01 AA24 AA41 AB01 AC26 AC31 AC56 3G093 AA01 BA04 BA23 CB09 CB10 DB05 DB18 5H180 AA01 CC04 LL09 LL15 5H301 AA03 CC06 EE07 EE12 EE27 GG09 GG14 LL11

Claims (10)

[Claims] 1. A steering angle detecting means for detecting a steering angle, an image information detecting means for detecting a road image in front of a host vehicle,
Traveling lane information detecting means for detecting traveling lane information including at least a radius of curvature of the traveling lane from a road image ahead of the host vehicle detected by the image information detecting means; and a steering torque for generating a steering torque according to the supplied current. Generating means, and steering torque control means for outputting a supply current for causing the steering torque generating means to generate a steering torque required to follow the travel lane, wherein the steering torque control means detects at least the travel lane information. Calculating a supply current for causing the steering torque generating means to generate a steering torque necessary for following the travel lane based on the travel lane information detected by the means and the steering angle detected by the steering angle detection means. Supply current calculation means, and supply to the steering torque generation means based on the radius of curvature of the travel lane detected by the travel lane information detection means. Lane following distance control device being characterized in that a supply current limit value setting means for setting a limit value of the current. 2. The supply current limit value setting unit, when the curvature radius of the traveling lane detected by the traveling lane information detection unit is small, sets the supply current limit value small. 5. The lane-following travel control device according to claim 1. 3. The steering torque generating means according to claim 1, wherein said steering torque control means gradually brings the supply current calculated by said supply current calculation means closer to a supply current limit value set by said supply current limit value setting means. Supply current asymptotic means for supplying current to the supply current, the supply current asymptotic means makes it possible to individually adjust the rate of change when decreasing the supply current and the rate of change when increasing the supply current, and The lane-following travel control device according to claim 2, wherein the change rate when the current is decreased is set to be larger than the change rate when the current is increased. 4. A vehicle speed detecting means for detecting a running speed of the own vehicle, wherein the supply current asymptotic means is used when the running speed of the own vehicle detected by the vehicle speed detecting means is high, when the supply current is reduced, and 4. The lane-following travel control device according to claim 3, wherein the rate of change when increasing is increased. 5. The supply current limit value setting means according to claim 1, wherein said supply current limit value is held when said travel lane information detecting means cannot detect a travel lane. The lane following travel control device according to any one of the above. 6. A lateral acceleration detecting means for detecting a lateral acceleration generated in the host vehicle, and said steering torque control means calculates a radius of curvature of a traveling lane from at least the lateral acceleration detected by said lateral acceleration detecting means. The supply current limit value setting means, based on the curvature radius of the traveling lane calculated by the curvature radius calculation means when the traveling lane information detection means cannot detect the traveling lane. The lane-following travel control device according to any one of claims 1 to 5, wherein a limit value of the supply current is set. 7. The method according to claim 7, wherein the curvature radius calculating unit detects the curvature radius of the traveling lane calculated from the lateral acceleration detected by the lateral acceleration detecting unit when the traveling lane information detecting unit detects the traveling lane. The lane-following travel control device according to claim 6, wherein an error from the calculated radius of curvature of the travel lane is calculated. 8. A vehicle, comprising: a vehicle speed detecting means for detecting a traveling speed of the host vehicle; wherein the curvature radius calculating means includes a low-pass filter for performing a low-pass filtering process on the lateral acceleration detected by the lateral acceleration detecting means; 8. The lane-following traveling control device according to claim 6, wherein the cutoff frequency of the low-pass filter is set smaller as the traveling speed of the host vehicle detected by the vehicle speed detecting unit is lower. 9. The driving lane information detecting means includes a lateral displacement detecting means for detecting a lateral displacement of the host vehicle with respect to the driving lane, and the steering torque control means includes a host vehicle detected by the lateral displacement detecting means. When the lateral displacement with respect to the traveling lane is equal to or more than a predetermined value, the traveling lane following traveling is deviated.
The supply current limit value setting means sets a small limit value,
2. The method according to claim 1, wherein when the supply current to the steering torque generating means is limited to a small value, a predetermined value of the lateral displacement for judging the deviation from the traveling lane-following traveling is set small.
The lane-following travel control device according to any one of claims 1 to 8. 10. The steering torque control means provides a change in steering torque when the supply current limit value setting means sets a small limit value and the supply current to the steering torque generation means is limited to a small value. The lane-following travel control device according to any one of claims 1 to 9, further comprising a steering torque variation adding unit.