JP3246424B2 - Lane departure prevention device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of controlling a vehicle by applying a steering control torque that the driver can easily overcome in addition to a steering torque applied by the driver in a direction to prevent the vehicle from deviating from the driving lane. The present invention relates to a lane departure prevention device for guiding lane departure prevention.

[0002]

2. Description of the Related Art In recent years, there has been developed a technology (driving guidance device) for grasping the position and attitude of a vehicle with respect to a traveling road, performing automatic driving control of a vehicle based on the position and guiding the driving of a driver. Is being developed. In the case of automatic cruise control, it is necessary to drive a car without relying on the driver at all, and various conditions such as the development of basic facilities (infrastructure) such as roads are premised on the practical application. Become.

[0003] On the other hand, in the case of a driving guide device, it is the driver who drives the car, and the driving guide device informs the driver of a driver's driving error and assists driving in a direction to eliminate the mistake. It is. Therefore, the driving guidance device has many technologies that can be realized even in the current road environment, and development of a driving guidance device with higher practicality is desired.

[0004] One of such driving guide devices is a lane departure prevention device. As this lane departure prevention device, there is a technology (Japanese Patent Laid-Open No. 63-214900) that issues a warning to a driving vehicle when a vehicle is inadvertently deviating from a driving lane. However, simply issuing a warning may not be effective for a driver who is dozing off, so that the steering control is more positively performed so that the vehicle travels at a certain position (for example, the center position) in the traveling lane. Technology (Japanese
Japanese Patent Application Laid-Open No.-104850) has also been proposed.

Further, in the case where the vehicle is controlled so as to maintain a fixed position in the traveling lane as described above, when the vehicle attempts to protrude from the traveling lane due to a temporary steering abnormality such as careless steering by a driver. If this control works, it may cause buffering with other vehicles. For this reason, in such a case, instead of returning the vehicle to a certain position in the driving lane, a technique of performing steering control so as to maintain a position biased to the side where the vehicle is going to protrude even in the driving lane ( JP-A-5-297939 has also been proposed.

[0006]

By the way, in the case of the lane departure prevention device which is one of the driving guide devices as described above,
In order to prevent the vehicle from deviating from the driving lane, it is necessary to apply a steering control torque through a steering actuator separately from the steering torque applied by the driver.However, the steering control torque to be applied in this case is limited to the vehicle. Should be added to prevent the driver from deviating from the lane in which the vehicle should travel, contrary to the driver's original intention.

That is, the driving guide device informs the driver of a driver's driving operation error or assists driving in a direction to eliminate the error, and the driver mainly performs the steering operation. Therefore, the driver's intention should be respected even in the lane departure prevention device, which is one of the driving guide devices, and it is necessary to suppress the steering control torque to a magnitude that the driver can easily overcome. . Further, the steering control torque must not be applied to prevent the driver from deviating from the driving lane by his / her own intention.
If the steering control torque is applied even in such a case, even if the control torque is large enough for the driver to easily overcome, the driver will feel uncomfortable.

For example, in the case of overtaking a preceding vehicle or avoiding an obstacle ahead, it is necessary to deviate from the driving lane once and change lanes. In such a case, it is necessary to prevent departure from the driving lane. When a proper steering control torque is applied, problems such as the driver's steering operation being hindered and lane change being delayed are caused. As a means for such a case, a technique of allowing a deviation from the traveling lane in the direction indicated by the turn signal (turn signal) (Japanese Patent Laid-Open No.
However, since all drivers do not always operate the turn signal when changing lanes, this technique cannot be used as a fundamental solution.

The vehicle departure prevention device is intended to prevent the danger of the vehicle deviating from the traffic lane. Even if the vehicle deviates from the traffic lane, the driver has normal attention. In this case, that is, when the consciousness level is high, the driver himself / herself returns to the traveling lane, so there is little risk of departure. In such a case, if the steering control torque is applied every time the vehicle departs from the traveling lane, the driver may feel troublesome.

On the other hand, when the driver loses his normal attention, for example, when he has a low level of consciousness, such as when he is drowsy, the vehicle is more likely to deviate from the driving lane. It is necessary to apply a steering control torque that is large enough to notify the driver of the lane departure and to guide the driver to the normal lane.

Therefore, the steering control torque should not always be given a constant magnitude, but should be set in accordance with the possibility of the lane departure, that is, in accordance with the driver's attention. In addition, when such a steering control torque is applied, it is generally considered that the driver responds according to the magnitude of the steering control torque. That is, when the steering control torque is increased, it is considered that the driver performs the steering operation for avoiding the lane departure relatively quickly. For this reason, the magnitude of the steering control torque should be set in accordance with the degree that the vehicle is going to deviate from the traveling lane (for example, the amount of lateral displacement of the vehicle from the reference position of the traveling lane). This is preferable for avoiding promptly and smoothly.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and provides an appropriate steering control torque in accordance with a driver's consciousness level without hindering a driver's intentional steering operation. It is an object of the present invention to provide a lane departure prevention device capable of accurately guiding a driver to avoid a lane departure without giving a sense of discomfort.

[0013]

Therefore, in the lane departure prevention apparatus according to the first aspect of the present invention, the lateral deviation amount calculating means calculates the lateral deviation amount of the traveling position of the vehicle from the reference position of the traveling lane, The control torque calculating means calculates a steering control torque that is large enough for the driver to easily overcome based on the lateral displacement calculated by the lateral displacement calculating means.

At this time, the control gain setting means of the control torque calculating means sets the control gain of the control torque calculated based on the lateral shift amount based on the driving situation of the vehicle detected by the driving situation detecting means. The control means controls the steering actuator of the vehicle such that the control torque set by the control torque calculation means is generated in a direction to reduce the lateral shift amount.

[0015] With this arrangement, the driver can easily overcome the steering torque applied by the driver in a direction to prevent the vehicle from deviating from the traveling lane in a direction to prevent the deviation from the traveling lane. The corresponding steering control torque is applied by the steering actuator to guide the prevention of lane departure of the vehicle. Note that a means (for example, a laser radar) for detecting an obstacle ahead of the vehicle may be provided as the driving state detecting means. In this case, an obstacle in front is detected by a detection means such as a laser radar, and the control gain is reduced according to a margin time until the obstacle is reached, so as to prepare for a deviation from the traveling lane due to the driver's intention. An arousal level detecting means for detecting the arousal level of the driver may be provided as the driving situation detecting means. In this case, as the arousal level detected by the arousal level detection unit is higher, the control gain is reduced, and the steering operation is entrusted to the driver.

Further, a steering torque sensor and / or a steering angle sensor may be provided as the driving condition detecting means. In this case, the steering torque sensor and / or the steering angle sensor detects the steering torque and / or the steering angular velocity input by the driver, and these steering torque and / or
Alternatively, the control gain is reduced according to the steering angular velocity, and deviation from the traveling lane by the driver's intention is allowed.

[0017]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a lane departure prevention device according to an embodiment of the present invention; FIG.
The lane departure prevention device (also referred to as a lane guidance system) is provided to prevent a vehicle from deviating from a driving lane in an automobile. When there is a possibility that the steering torque is different from the steering torque applied by the driver by the steering actuator 21 provided in the vehicle as shown in FIG. 1 (this steering torque is used to distinguish it from the steering torque applied by the driver). Control torque) to warn the driver during steering of a lane departure through a steering wheel (hereinafter, also referred to as a steering wheel) 20.

Of course, the steering control torque itself is also
The main purpose of this steering control torque is to alert the driver through the steering system, and to correct the position of the vehicle that is likely to deviate from the lane. It should be performed by a driver's steering operation that recognizes that the vehicle is likely to depart from the lane due to the application of the control torque.

Therefore, the present lane departure prevention device is shown in FIG.
As shown in FIG. 1, in order to recognize the position of the host vehicle with respect to the traveling lane, a camera 2 serving as an image pickup means for taking an image of a road state ahead of the vehicle 1 and image information from the camera 2 are appropriately processed so as to be on the road ahead. Image information processing means 3 for recognizing the left and right white line positions, and predicts a lateral shift amount ΔY after a predetermined time t from the reference position of the traveling lane (traveling lane) from the white line position image information by the image information processing means 3 And a lateral acceleration calculating means 7 for calculating a lateral acceleration G acting on the vehicle.

It should be noted that the lateral deviation amount ΔY corresponds to a determination parameter relating to the degree that the vehicle 1 is likely to deviate from the lane, and the lateral acceleration G corresponds to a determination parameter relating to the driver's burden on a curved road. Also, the lateral displacement amount calculating means 4A
Are provided as functional elements in the traveling lane estimating means 4 for estimating the relative position of the traveling lane (traveling lane) with respect to the own vehicle, together with the road curvature calculating means 4B for computing the road curvature ρ which is a determination parameter of the lateral acceleration G. ing.

Further, the present lane departure prevention apparatus is provided with a lateral deviation amount (lateral deviation) Δ calculated by the lateral deviation amount calculating means 4A.
Y, that is, a control torque calculating unit that calculates the steering control torque Tc based on the degree of departure from the lane and the lateral acceleration G calculated by the lateral acceleration calculating unit 7, that is, the burden on the driver on a curved road. 5, a steering actuator 21 capable of applying a steering control torque to the steering system separately from the steering torque applied by the driver, and the steering control torque Tc calculated by the control torque calculation means 5 reduces the lateral deviation amount ΔY; , A control means (controller) 6 for controlling the steering actuator 21 so as to be generated in a direction opposing the lateral acceleration G.

Further, a switch (SW) 23 for selecting the operation of the lane departure prevention device is provided. Therefore, if you want to operate this device, turn on the switch 23,
If you do not want to operate this device, turn off switch 23,
It can be selected according to the driver's preference.
Further, for example, in the instrument panel (instrument panel), when the switch 23 is turned on or when a control torque for preventing lane departure is applied, an operation display section 24 for displaying the control torque is provided. I have.

The image information processing means 3, the traveling lane estimating means 4 (lateral displacement amount calculating means 4A, road curvature calculating means 4
B), the lateral acceleration calculation means 7, the control torque calculation means 5, and the controller 6 are a CPU, an input / output interface,
It is configured as an electronic control unit including M, RAM, and the like. First, the position of the host vehicle with respect to the driving lane is recognized,
That is, the calculation of the lateral deviation amount ΔY of the host vehicle will be described.

In the image information processing means 3, first, as shown in FIG. 2, an original image 3A from the camera 2 is fetched, a road white line is extracted from the original image 3A, and an image of the extracted road white line is converted into a vertical image. The image is converted into a planar view image 3B as viewed from above. Next, the recognition of the white lines 12L and 12R is shown in FIG.
This will be described with reference to FIG. Here, the recognition of the white line 12L as the road side line at the left end of the traveling lane will be described. However, the same applies to the case where the white line 12R at the right end of the traveling lane is used as a reference. I will call it.

Next, in the image information recognizing means 3, FIG.
As shown in (a), the camera 2 provided in the vehicle 1 uses a camera 2 in a flat area to cover the area in front of the vehicle (for example, 5 m to 30 m).
m), the monochrome image information is fetched, and a part of the image in the vertical direction on the screen is omitted from the image information. Then, a plurality of horizontal lines 11 are set at regular intervals on this screen. The capture of the black-and-white image information is updated every minute control cycle. As shown in FIG. 3B, on each horizontal line 11, the left and right positions of the white line position on the previous screen are required. (Here, the left and right 50 pixels [do
t]) is set as the white line search area (processing target area) 10. For the first screen, the white line position on the straight road is used as the previous screen data.

Then, as shown in FIG. 3C, the brightness of each horizontal line is differentiated in the horizontal direction from the left. Reference numeral 14 in the drawing is a guardrail. By the way, a normal road surface has low luminance and a small change in luminance. On the contrary,
Since the brightness of the white line 12 is much higher than that of the normal road surface, when the brightness of the road is differentiated in this way, the luminance change is positive at the boundary point from the normal road surface to the white line 12, and the white line 12 changes to the normal road surface. Is obtained at the boundary point of which the luminance change becomes negative. An example of such differential data is shown in FIG.

Then, for each of the data of each horizontal line 11, peaks of the differential values appear in the order of plus and minus from the left, and the interval between the peaks is the white line 12.
Is extracted as a white line candidate as a combination that is considered to be appropriate (the interval from the positive peak to the negative peak is within 30 dots, for example).
As shown in FIG. 3E, the midpoint M is set to the white line candidate point 15.
Save as

Then, among these white line candidate points 15,
Only the point closest to the screen center is left as the final candidate point.
This means that, for example, when the vehicle 1 is traveling on the left side, the search area 1
The right side of 0 is a road surface with little change in normal luminance, and the white line candidate point 15 closest to this normal road surface can be determined as the white line 12. Therefore, further to the left of the white line 12,
Objects that cause noise (for example, guardrails 14)
Is present, the white line 12 can be reliably recognized from the image information captured by the camera 2.

Finally, as shown in FIG. 3F, the vertical continuity of the white line candidate points 15 in each horizontal line data is sequentially verified from the bottom of the screen. First, the inclination between the upper and lower ends of the white line 12 on the previous screen is calculated in advance.
Then, assuming that the lowest point 15A is the white line 12, it is verified whether or not the candidate point 15B on the horizontal line 11 which is only one line above is within the range of ± 50 dots of the inclination of the previous white line 12.

If the candidate point 15B falls within this range, it is regarded as a white line. If not, the candidate point 15B is rejected, and the coordinates interpolated from the above-mentioned inclination are regarded as the white line position. By performing the same operation for each horizontal line for this detection, a continuous white line 12 can be recognized. Such white line recognition work is continuously performed at a required cycle, and the recognition of the white line 12 is updated each time.

White line 12 as the roadside line at the right end of the traveling lane
The recognition of R is performed in the same manner. The driving lane estimating means 4 converts the white lines 12R and 12L on the original image 3A recognized in each recognition cycle as described above into a planar view image 3B, and estimates the road center line LC from the white line 12L at the left end of the driving lane. based on the road centerline LC _R which may be estimated from _L and the traveling lane right edge of the white line 12R, road centerline L
C is estimated. Then, based on the road center line LC, the lateral displacement amount ΔY ₀ and the deviation angle β at the present time are calculated by the lateral displacement amount calculating means 4A.

The declination β is an angle formed between the tangent direction of the curved road center line LC and the traveling direction of the vehicle, as shown in FIG. The tangent direction of the road center line LC is from the road center line position (reference line position) at the first detection point (shown as perigee in the figure) which is the detection level closest to the vehicle in the image information obtained from the camera image. This is a direction toward a road center line position (reference line position) at a second detection point (shown as an apogee in the figure) further away from the vehicle 1 by a predetermined distance L than this perigee, and is calculated from each position information. be able to. Further, the vehicle traveling direction is a direction toward the vehicle position at a point in time when the vehicle is separated from the current vehicle position by a predetermined distance L while maintaining the current steering angle, and can be calculated from information of these two points.

In this example, the center line of the host vehicle at the first detection point which is the closest point to the vehicle (see point P1).
The lateral distance between the road and the road center line LC (see the point LC1) (the distance in the road width direction, that is, the lateral direction of the camera image) is calculated as the current lateral displacement amount (current lateral deviation) ΔY ₀ . Further, the second detection point is a point (LC2, P2) that can be predicted to arrive after a predetermined time t from the first detection point, that is, a distance obtained by multiplying the current vehicle speed V by the predetermined time t from the first detection point. L (= Vt), and the first detection point (LC1) and the second detection point (LC
2) and the traveling direction line of the vehicle 1 (P1P
2) is calculated as the argument β. The vehicle position (P2) that can be predicted to arrive after the predetermined time t is calculated based on the steering angle α detected by the steering angle sensor 27.

The lateral displacement amount calculating means 4A multiplies the declination angle β calculated as described above by the vehicle speed V of the vehicle detected by the vehicle speed sensor 32 and a predetermined time t, and calculates the lateral deviation change amount Δy ( [Delta] y = calculates β × V × t), the predicted lateral deviation by adding the lateral deviation (lateral deviation) [Delta] Y ₀ at the present time to (hereinafter, referred to simply as the lateral shift amount) [Delta] Y (= [Delta] Y
₀ + β × V × t). The predetermined time t is set to an appropriate time in consideration of the driver's general operation speed of the steering wheel 20 and the speed of recognition of road conditions by the image information processing means 3 and the like. Further, it may be variable according to the vehicle speed V, and the predetermined time t may be set so that the distance L from the first detection point to the second detection point is constant.

On the other hand, the road curvature calculating means 4B estimates the curvature (road curvature) ρ of the traveling lane based on the image information of the road center line. First, as shown in FIG. 5, for example, the above-mentioned first detection point (LC1) and second detection point (LC2) are further changed to a second detection point (LC2).
A third detection point (LC3) forward by a distance L from
A first vector LC1LC2 from the first detection point (LC1) to the second detection point (LC2), and a second detection point (LC2)
Vector LC2 from the second detection point (LC3) to the third detection point (LC3)
The angle θ formed with LC3 is calculated as a curvature index (curvature characteristic) at the second detection point (LC2).

Then, the curvature (road curvature) ρ of the driving lane is calculated from the distance L and the curvature index θ by the following equation. ρ = 2 sin (θ / 2) / L (1) In other words, the value of the curvature index θ is the second detection point (LC2)
Is an index representing the degree of curvature of the curve at
Is larger, the curvature ρ of the curve at the second detection point (LC2) is larger, indicating that the curve is steeper.

The lateral acceleration calculating means 7 calculates the lateral acceleration G acting on the vehicle based on the curvature ρ of the traveling lane calculated by the road curvature calculating means 4B in this way. That is, assuming that the magnitude of the traveling speed of the vehicle detected by the vehicle speed sensor 32 is V, the lateral acceleration G is calculated by the following equation. G = ρ × V ² (2) The vehicle 1 has a lateral acceleration sensor 31.
Can be detected.

The control torque calculating means 5 performs steering based on the lateral displacement ΔY of the vehicle with respect to the reference position of the traveling lane (the center position of the road width) thus calculated and the lateral acceleration G acting on the vehicle 1. The control torque Tc is set,
The present device is characterized by the setting of the steering control torque Tc. That is, in the present device, not only the torque for preventing the lateral displacement of the vehicle (lateral displacement preventing torque), but also the torque for facilitating the steering of the steering wheel with respect to the lateral acceleration applied to the vehicle (the steering maintenance assisting torque). The control torque for steering is set based on the torque).

That is, as shown in FIG. 12, the control torque calculating means 5 calculates the side slip prevention torque Ty and multiplies the side slip prevention torque Ty by a predetermined gain Ky (the control torque calculation means for the side slip corresponding steering). 5A) and a function (steering control torque correcting means) 5B for correcting the value Ky · Ty calculated by the calculating means 5A according to the lateral acceleration applied to the vehicle.

The correcting means 5B calculates a steering assist torque Tg and multiplies the steering assist torque Tg by a predetermined gain Kg (correction amount calculating means) 5a, and a value calculated by the correction amount calculating means 5a. A correction amount adding means 5b is provided for performing correction by adding Kg · Tg to the lateral shift corresponding steering control torque Ky · Ty to obtain a corrected steering control torque (Ky · Ty + Kg · Tg).

The correction using the steering assist torque in accordance with the lateral acceleration requires a steering force opposing the lateral acceleration when the vehicle is subjected to the lateral acceleration. This is because the steering control for preventing the lane departure can be performed without a sense of incongruity even on a curved road or the like.
Generally, when the vehicle is traveling on a curved road, the centrifugal force acting in the lateral direction of the vehicle acts in the direction that hinders turning according to the curvature of the curve and the traveling speed of the vehicle. Steering assist torque Tg according to the magnitude
Is added to correct the steering control torque.

Here, the side slip prevention torque Ty will be described. The side slip corresponding steering control torque calculating means 5A sets the side slip prevention torque Ty in proportion to the side slip amount ΔY as shown in FIG. In FIG. 6, the abscissa regarding the lateral deviation amount ΔY indicates a lateral deviation to the right in the right direction, and a lateral deviation to the left in the left direction. The left steering indicates left steering and the downward steering indicates right steering guiding the vehicle to the right side of the lane.

That is, as shown in FIG. 6, when the vehicle deviates from the road center line to the right side, a lateral deviation prevention torque Ty for leading the vehicle to the left side of the lane is set according to the lateral deviation amount ΔY. If the vehicle deviates from the road center line to the left, a lateral deviation prevention torque Ty for right steering that guides the vehicle to the right side of the lane is set in accordance with the lateral deviation ΔY. However, in each case, the magnitude of the lateral displacement prevention torque Ty is limited by a constant value Tym. Here, when the magnitude of the lateral deviation amount ΔY becomes Y1, the magnitude of the lateral deviation prevention torque Ty is limited to a constant value Tym. This is because the side slip prevention torque Ty is different from the steering torque used for automatic steering, and its main purpose is to warn the driver. Since the vehicle position is corrected by the driver's steering operation, the steering control torque is used. Tc is limited to a size that does not hinder the driver's steering operation, that is, a size that the driver can easily overcome.

The correction amount calculating means 5a, which is a functional element of the steering control torque correcting means 5B, sets the steering assist torque Tg in proportion to the lateral acceleration G as shown in FIG. In FIG. 8, the abscissa regarding the lateral acceleration G indicates that the right direction indicates the effect of the lateral acceleration of the vehicle in the right direction and the left direction indicates the effect of the lateral acceleration of the vehicle in the left direction. The ordinate relating to the torque Tg indicates left steering in which the upward direction guides the vehicle to the left side of the lane, and rightward steering in which the downward direction guides the vehicle to the right side of the lane.

As shown in FIG. 8, if lateral acceleration acts on the vehicle in the right direction, a left steering assist torque Tg for guiding the vehicle to the left side of the lane is set in accordance with the lateral acceleration G, and the vehicle is subjected to the lateral acceleration G. If lateral acceleration in the left direction acts, the steering assist torque T for right steering that guides the vehicle to the right side of the lane according to the lateral acceleration G.
Set g. However, in any case, the steering assist torque Tg
Is limited by a constant value Tgm. Here, if the magnitude of the lateral acceleration G becomes G1, the steering assist torque Tg
Is limited to a constant value Tgm. This limits the driver to a size that can be easily overcome, as described above.

The correction amount calculating means 5a multiplies the steering assist torque Tg thus calculated by an appropriate gain Kg. The correction amount adding means 5b performs correction in accordance with the lateral acceleration of the vehicle by adding to the steering control torque Ky · Ty corresponding to the lateral deviation calculated from the lateral deviation amount ΔY, and obtains the corrected steering control torque (Ky × Ty + Kg). × Tg).

In this manner, the steering control torque is calculated based on the lateral displacement amount ΔY and the lateral acceleration G. As shown in FIGS. 1 and 12, the control torque calculating means 5 further controls the steering control torque. Gain setting means 5C is provided;
The control gain is set by the control gain setting means 5C according to the operating condition. That is, the control gain setting means 5C outputs the corrected steering control torque (Ky × Ty + Kg × T) corrected by the steering control torque correction means 5B.
g) includes gains Ka and K corresponding to various driving situations.
b, Kc1, Kc2, and Kd to obtain a final steering control torque Tc [Tc = Ka.Kb.Kc1.K.
c2 · Kd · (Ky × Ty + Kg × Tg)].

First, the control gain setting means 5C sets the gain Ka in accordance with the time to the front obstacle.
That is, when there is an obstacle such as a preceding vehicle on the same lane ahead of the host vehicle, the driver operates the steering wheel to deviate once from the traveling lane and is likely to avoid the obstacle ahead. Even in such a case, if the steering control torque is applied to the deviation from the traveling lane, there is a possibility that a problem such as a delay in the steering operation of the driver may occur. For this reason, if there is an obstacle ahead, it is necessary to allow the driver to operate the steering wheel to avoid this obstacle.However, the possibility that this driver will operate the steering wheel is limited until the vehicle reaches the obstacle. It is considered that the higher the time (the extra time), the higher the time.

Therefore, the vehicle 1 is provided with one of driving condition detecting means.
A laser radar 29 is provided as one obstacle detecting means. The control gain setting means 5C detects an obstacle on the same lane ahead by the laser radar 29, and determines a relative distance between the vehicle 1 and the obstacle. And the relative speed are detected, and a margin time (relative distance / relative speed) until the vehicle 1 reaches an obstacle is obtained.

Then, as shown in FIG. 10A, the setting is made such that the gain Ka is gradually reduced as the margin time is shorter. In FIG. 10 (a), 0 the gain Ka if spare time is t ₁ or less, ie, so that no added steering control torque, which when margin time is t ₁ or less, the driver handle the possibility of performing the operation is for a very high likelihood margin time conversely to perform the steering operation in the case of t ₂ or more is set to 1 very low because the gain Ka.

By decreasing the gain Ka in accordance with the allowance time in this way, it is possible to cope with a deviation from the traveling lane due to the driver's intention. Next, the control gain setting means 5C sets the gain Kb according to the driver's consciousness level (arousal level). In other words, if the driver's awakening degree is high, even if the driver deviates from the driving lane, the risk is low, and the application of the steering control torque may be rather troublesome, whereas if the driver's awakening degree is low, the driving lane is low. Therefore, the setting is made such that the gain Kb increases as the awakening degree of the driver decreases.

The arousal level of the driver is detected by arousal level detection means (driver monitor system) 26 as driving state detection means provided in the vehicle 1. This arousal level detecting means 26 is provided for determining individual differences between drivers,
Any configuration can be used as long as the level of arousal can be detected without depending on physical condition. For example, a technique disclosed in Japanese Patent Application Laid-Open No. 7-9879 may be used. .

According to this technique, the awakening degree detecting means 26 has a lateral deviation standard deviation calculating means and a steering wheel deviation standard deviation calculating means as functional elements. First, the lateral deviation standard deviation calculating means comprises a lateral deviation amount calculating means. The standard deviation of the lateral shift amount ΔY is calculated by statistically processing the lateral shift amount ΔY calculated by 4A. On the other hand, the steering operation deviation standard deviation calculating means firstly comprises the road curvature calculating means 4B.
Based on the information on the road curvature ρ calculated by the above, a reference steering angle when the vehicle 1 traces the traveling lane is calculated from the driver model. Next, the reference steering angle is compared with the steering angle α detected by the steering angle sensor 27, and the standard deviation of the steering operation deviation Δα is calculated by statistically processing the steering operation deviation Δα with respect to the reference steering angle. Has become.

Based on the information on the standard deviation of the lateral deviation ΔY and the standard deviation of the steering wheel deviation Δα, the awakening degree detecting means 26 determines whether or not the traveling lane is straight,
If the calculated standard deviation of the lateral shift amount ΔY is large, it is determined that the driver's awakening degree is low. If the running lane is a curve, the driver's awakening degree is low if the calculated standard deviation of the steering wheel operation deviation amount Δα is large. Is to be determined.

When the awakening degree of the driver is detected in this way, the control gain setting means 5C sets the gain Kb to gradually increase as the awakening degree decreases, as shown in FIG. 10 (b). . In FIG. 10B, the arousal level is a ₁
Although the following cases are a gain Kb and 1, which in the case of the degree of awakening is a ₁ or less, there is a fear such that the driver feels sleepy, the risk when the vehicle is deviating from the driving lane is extremely large This is to prevent the vehicle from deviating from the traveling lane by positively applying the steering control torque. On the other hand, when the arousal level is equal to or more than a ₂ , the driver is considered to have sufficient attention, and the gain Kb is reduced to the predetermined value k _b1 so as not to bother the user. However, even in such a case, there is a possibility that the driver may make an operation error, so that the operation is not reduced below the predetermined value k _b1 .

Further, the control gain setting means 5C sets the gains Kc1 and Kc2 in accordance with the steering torque of the steering wheel and the steering angular velocity, respectively. That is, when the driver intends to deviate from the driving lane due to his / her own intention, it is considered that the steering wheel is steered by a large steering torque and a steering angular velocity as compared with the case where the driver deviates from the driving lane due to falling asleep. It is presumed that the greater the steering angular velocity, the greater the possibility that the driver intends to deviate from the traveling lane by himself.

Therefore, the steering torque of the steering wheel is detected by a steering torque sensor 28 provided as a driving condition detecting means provided on the steering shaft 40 (shown in FIGS. 1 and 13). Further, the steering angular velocity is calculated based on the steering angle α detected by the steering angle sensor 27 as the driving situation detecting means. Then, the control gain setting means 5C outputs a gain K corresponding to the steering torque and the steering angular velocity.
c1 and Kc2 are set.

That is, as shown in FIGS. 10 (c) and 10 (d), the gains Kc1 and Kc2 are set to gradually decrease as the steering torque increases and the steering angular velocity increases, respectively. FIG. 10 (c), the are not exert (d) is in, when the steering torque is T [alpha ₁ or more, and each in the case of the steering angular velocity is V.alpha ₁ or more gain Kc1, Kc2 0, i.e. steering control torque but this is the case of the steering torque T [alpha ₁ or more, and in the case of the steering angular velocity is V.alpha ₁ or more, the driver because it is highly likely doing the deviation operation from the travel lane by its own will.

As described above, by decreasing the gains Kc1 and Kc2 in accordance with the steering torque and the steering angular velocity, a deviation from the traveling lane by the driver's intention is allowed. Further, the control gain setting means 5C sets the gain in accordance with the allowance time, the awakening degree, the steering torque, and the steering angular velocity as described above, and also uses the turn signal information as control information for setting the gain. That is, when the driver intends to change lanes or make a right or left turn by his or her own intention, the driver instructs the direction in which the driver intends to depart from the turn signal 30, although not necessarily. Therefore, when the driver instructs the departure direction with the turn signal 30, the departure in the instructed direction is permitted by setting the gain Kd to 0 only for the steering control torque in the instructed direction.

The steering actuator 21 may be any actuator that can apply a torque to the steering shaft. For example, as shown in FIG. 13, the steering actuator 21 is installed below the torsion bar (not shown) of the steering shaft 40 (on the power steering side). It may be constituted by the small electric torque motor 41 described above. In this case, the motor 4
1 is transmitted to the steering shaft 40 via a worm gear 42 including a worm 42a and a worm wheel 42b.
A torque limiter 43 is interposed between b and the steering shaft 40. The torque limiter 40 allows the driver to easily operate the handle 20 even if the motor 41 is stuck. Further, the maximum torque of the motor 41 is set to a necessary minimum, so that even if a failure occurs in the controller 6, excessive control torque is not transmitted to the driver.

The output of the control torque calculation signal is provided between the control torque calculation means 5 and the controller 6 such that the control torque actually exerted by the steering actuator 21 continues smoothly without a sudden change. A low-pass filter 25 for performing a smoothing process is provided. The lane departure prevention device as one embodiment of the present invention is configured as described above.
This is performed as shown in FIG.

That is, it is determined whether or not the control switch 23 is turned on (step S10). If the control switch 23 is not turned on, the lane departure prevention process is not performed. If the control switch 23 is turned on, step S20 is performed. The following processing is performed. That is, first, a control torque according to the lateral deviation amount is calculated by the lateral deviation corresponding steering control torque calculating means 5A (step S20), and the control torque is corrected by the steering control torque correcting means 5B based on the lateral acceleration (step S20). S
30) Further, the gain of the control torque is set by the control gain setting means 5C according to the operating condition (step S).
40). Then, the controller 6 operates the steering actuator 21 with a control amount corresponding to the control torque corrected based on the lateral acceleration, and outputs a display signal to the operation display unit 24 (step S50).

This process will be described with reference to the block diagram shown in FIG. 12. The driver performs a steering operation by appropriately judging the traveling lane while visually recognizing this. On the other hand, in the present lane departure prevention device (lane guidance system), first, lane recognition for the traveling lane is performed by image recognition through the camera 2, and a predetermined lane from the reference position of the vehicle lane (here, the road center line LC). The lateral shift amount ΔY after a time is calculated, and the lateral shift prevention torque Ty is calculated from the lateral shift amount ΔY. Next, the lateral acceleration G acting on the vehicle is calculated based on the curvature ρ of the traveling lane detected by the lane recognition for the traveling lane, and the steering assist torque Tg is calculated from the lateral acceleration G. Tg is the lateral displacement prevention torque Ty
Is added to. Further, the gains Ka, Kb, Kc1, Kc, and Kd are set based on various driving situations, and the steering actuator 21 is operated based on the steering control torque Tc thus obtained.

As a result, the steering torque of the driver and the control torque for steering by the steering actuator 21 are added and transmitted to the steered wheels 22 via the power steering device to steer the steered wheels 22. is there.
More specifically, when calculating the control torque, it is necessary to first calculate a lateral shift amount ΔY, which is an index of how much the vehicle deviates from the traveling lane after a predetermined time. In this device, first, the traveling lane estimating means 4 estimates the relative position of the traveling lane (traveling lane) with respect to the own vehicle, and calculates the lateral displacement amount calculating means 4A.
Is the current lateral shift amount ΔY ₀ based on the relative position.
Is calculated. Here, based on the image information from the camera 2, the lateral distance (the road width direction, the lateral distance of the camera image) between the vehicle center line and the road center line LC at the point (first detection point) closest to the vehicle based on the image information. Is the lateral deviation (lateral deviation) Δ
It is calculated as Y _0.

When the current lateral shift amount ΔY ₀ is calculated in this manner, the reference line position information at the first detection point separated by a predetermined distance from the vehicle and the distance L from the vehicle 1 further than this perigee are further determined. The tangent direction of the curved road center line LC is calculated from the reference line position information at the second detection point. Further, the vehicle traveling direction is calculated from the current vehicle position information and the vehicle position information at the time when the vehicle is separated by the distance L while maintaining the current steering angle, and the vehicle traveling direction and the tangential direction of the road center line LC are calculated. The deviation angle β to be formed is calculated.

Here, as shown in FIG. 4, the second detection point (LC2) can be predicted to reach the first detection point (LC1) after a predetermined time t, that is, the first detection point (L
These first detection points (L) are located at a distance L obtained by multiplying the current vehicle speed V by a predetermined time t from C1).
The angle between a straight line connecting C1) and the second detection point (LC2) and the traveling direction line of the vehicle 1 is calculated as the declination β.

In this manner, the current lateral displacement amount ΔY
_{When 0} and the deflection angle β are calculated, the lateral shift amount calculation means 4A calculates
Further, the deviation angle β is multiplied by the vehicle speed V of the vehicle detected by the vehicle speed sensor 32 and a predetermined time t to obtain a lateral shift change amount Δy (Δy = β
× V × t) is calculated, and the current lateral shift amount (lateral deviation) ΔY ₀ is added to this to calculate a predicted lateral shift amount ΔY (= ΔY ₀ + β × V × t) after a predetermined time t.

On the other hand, the lateral acceleration G, which is an index of the magnitude of the centrifugal force acting to prevent the vehicle from turning on a curved road, is calculated by the lateral acceleration calculating means 7.
The curvature (road curvature) ρ of the traveling lane is estimated by the road curvature calculating means 4B, which is a functional element of the traveling lane estimation means 4, based on the image information of the road center line LC, and the lateral acceleration G is calculated based on the road curvature ρ. calculate.

That is, as shown in FIG. 5, a first detection point (LC1) and a second detection point (L
With respect to C2), a third detection point (LC3) is taken further by a distance L from the second detection point (LC2), and a first detection point (LC1) extending from the first detection point (LC1) to the second detection point (LC2). The angle θ between the vector LC1LC2 and the second vector LC2LC3 from the second detection point (LC2) to the third detection point (LC3) is calculated as a curvature index (curvature characteristic) at the second detection point (LC2). And these distances L
The curvature (road curvature) ρ of the traveling lane at the second detection point (LC2) is calculated from Equation (1) using the equation (1), and the traveling speed V of the vehicle detected by the vehicle speed sensor 32 is used. Then, the lateral acceleration G is calculated from the equation (2).

When the lateral displacement ΔY and the lateral acceleration G are calculated in this way, the control torque calculating means 5 first
As shown in FIG.
The lateral displacement prevention torque Ty is calculated using a map, a table, or an arithmetic expression as shown in FIG. Side slip prevention torque Ty
Is proportional to the amount of lateral shift ΔY, and its magnitude is limited to a fixed value. That is, as shown in FIG. 6, when the vehicle shifts to the right from the road center line, a left-side steering side slip prevention torque Ty that guides the vehicle to the left side of the lane is set according to the side shift amount ΔY. If the vehicle is deviated to the left, the lateral deviation prevention torque Ty for right steering that guides the vehicle to the right side of the lane is set according to the lateral deviation amount ΔY, but in any case, the magnitude of the lateral deviation prevention torque Ty is limited by a constant value Tym. .

By limiting the side slip prevention torque Ty in this way, the side slip prevention torque Ty does not become excessive, and the magnitude of the side slip prevention torque Ty is maintained to such an extent that the driver can easily overcome. When the lateral displacement prevention torque Ty is applied, the driver senses the lane departure (departure from the road center line) and the direction of correction from the steering feeling of the steering wheel 20 or the like, and the correction of the vehicle position is promptly performed by the driver's steering operation. Will be performed. The side slip prevention torque Ty itself is effective not only for warning the driver, but also for correcting the vehicle position. Further, the warning by the side slip prevention torque Ty is also effective for, for example, a driver of inattentive driving. In this case, the driver is encouraged to prevent inattentive driving while preventing a deviation from the lane.

The side slip prevention torque Ty is calculated not only by the side slip amount ΔY _{0 at} the present time but also by the side slip change amount Δy after a predetermined time t predicted from the vehicle speed V and the declination β at the current side slip amount ΔY _0. Since it is determined on the basis of the predicted lateral shift amount ΔY obtained by the addition, the degree of deviation of the vehicle is estimated in advance, and control can be performed to prevent the vehicle from deviating so that control delay does not occur. Guidance for departure prevention can be given accurately according to the situation.

It should be noted that the control torque calculating means 5 for side-shift steering is provided.
The calculation of the lateral shift prevention torque Ty by A is performed by calculating the lateral shift amount ΔY.
However, the characteristics are not limited to those shown in FIG. In other words, the lateral displacement prevention torque Ty may be any value that acts to reduce the lateral displacement amount ΔY as it increases. In particular, in a region where the lateral displacement amount ΔY is small, the lateral displacement prevention torque Ty is set to 0, and in this region (dead zone) If the magnitude of the lateral deviation amount ΔY is larger than the value of ()), the lateral deviation prevention torque Ty
May be set according to the lateral shift amount ΔY. In this case, the lateral deviation prevention torque Ty may be linearly increased with respect to the lateral deviation amount ΔY, or may be increased stepwise.

Further, as shown in FIG. 7, when the magnitude of the lateral deviation ΔY is larger than that of the dead zone, the lateral deviation Δ
A lateral displacement prevention torque T of a certain magnitude in the direction in which Y decreases
ym may be set. Next, the control torque calculating means 5 uses the steering control torque correcting means 5B to
The steering assist torque Tg is calculated using a map, a table, or an arithmetic expression as shown in FIG. That is, as shown in FIG. 8, when the traveling lane is curved to the left,
Since the lateral acceleration G acting on the vehicle acts in the right direction that hinders the turning of the vehicle, the steering assist torque Tg for left steering for turning the vehicle to the left is set according to the magnitude of the lateral acceleration G, and the driving lane is shifted to the right. If the vehicle is curving in the direction, a steering assist torque Tg for right steering for turning the vehicle to the right is set according to the magnitude of the lateral acceleration G. However, in order to maintain the magnitude of the steering assist torque Tg to such an extent that the driver can easily overcome, when the magnitude of the lateral acceleration G is equal to or more than G1, the magnitude of the steering assist torque Tg is limited to a constant value Tgm.

When the steering assist torque Tg is given,
The driver can reduce the steering force of the steering wheel 20 on a curved road, and can easily perform the steering operation even when a large lateral acceleration G acts. Further, since the steering assist torque Tg predicts in advance the lateral acceleration G that will be exerted on the curve where the vehicle is going to enter, and is determined based on the predicted lateral acceleration G, the driver is required to apply the curve to the curve. The steering assist torque Tg can be added so as to encourage steering along the steering wheel. For this reason, the steering assist torque Tg also has the effect of alerting the driver that the vehicle is approaching a curve, and is effective, for example, for a driver in inattentive driving.

When the lane recognition becomes unstable due to the road surface condition and the lateral acceleration G cannot be calculated, the steering assist torque Tg can be applied based on the lateral acceleration directly detected through the lateral acceleration sensor 31. So
Thus, the lane guidance control can be continued regardless of the road surface condition. That is, robustness can be ensured.

The calculation of the steering assist torque Tg by the steering control torque correcting means 5B is not limited to the characteristic shown in FIG. In other words, the steering assist torque Tg may have a tendency to eliminate this effect as the lateral acceleration G increases. For example, as shown in FIG. Assuming that Tg is 0, the lateral acceleration G is higher than this area (dead zone).
When the magnitude of the steering assist torque Tg increases, the steering assist torque Tg may be set according to the lateral acceleration G.

When the steering control torque is calculated based on the lateral shift amount ΔY and the lateral acceleration G in this manner, the control torque calculating means 5 further sets the gain setting according to the driving condition by the control gain setting means 5C. I do. First, the control gain setting means 5C detects an obstacle on the same lane ahead by the laser radar 29 as an obstacle detecting means, detects a relative distance and a relative speed between the vehicle 1 and the obstacle, and The time to reach the obstacle (relative distance / relative speed) is obtained. Then, the gain Ka is set so as to correspond to the time to the front obstacle and gradually decrease as the time to spare decreases as shown in FIG.

By setting the gain Ka in this way, when the allowance time is short and the urgency of the steering operation is high, the gain Ka is also reduced accordingly, so that the driver can easily operate from the driving lane by his own operation. When the margin time is long and the urgency of the steering wheel operation is low, the gain Ka increases accordingly, so that it is possible to prevent the vehicle from deviating from the traveling lane due to a drowsiness or an operation error. Further, since the gain Ka gradually decreases in accordance with the allowance time, the driver does not feel a sense of incongruity due to a sudden change in the gain Ka.

Note that t ₁ and t in FIG.
₂ can set an appropriate value as long as the lane departure can be sufficiently prevented and the driver does not feel uncomfortable, and is limited to the setting map shown in FIG. Not something. Next, the control gain setting means 5C uses the awakening degree detecting means 26 to set the lateral shift amount ΔY
And the driver's consciousness level (degree of arousal) is detected based on the information on the standard deviation of the steering operation deviation amount Δα. Then, as shown in FIG. 10B, the gain Kb is set so as to gradually increase as the arousal level decreases.

By setting the gain Kb as described above, it is possible to prevent the driver from feeling annoying by applying the steering control torque when the arousal level is high, and to reduce the arousal level with a high danger level. It is possible to prevent lane departure when the vehicle is low. Further, since the gain Kb is gradually reduced in accordance with the arousal level, the driver does not feel a sense of incongruity due to a sudden change in the gain Kb.

The values of a ₁ , a ₂ and the predetermined value k _b1 may be appropriately set as long as both the prevention of the driver's complexity and the prevention of the lane departure can be achieved and the driver does not feel uncomfortable. Can be set, and FIG.
The present invention is not limited to the setting map shown in FIG. Further, the control gain setting means 5C includes the steering torque sensor 2
8 and the steering angle sensor 27 detect the steering torque and the steering angular velocity of the steering wheel, respectively, and FIG. 10 (c) and (d).
As shown in (1), the gains Kc1 and Kc2 are set so as to gradually decrease as the steering torque increases and as the steering angular velocity increases.

By reducing the gains Kc1 and Kc2 in accordance with the steering torque and the steering angular velocity in this manner, when the driver operates the steering wheel by his / her own intention, the driver can easily deviate from the traveling lane and fall asleep. Departure from the traveling lane due to, for example, can be prevented. Further, since the gains Kc1 and Kc2 gradually decrease in accordance with the steering torque and the steering angular velocity, respectively, the gains Kc1 and Kc2 do not suddenly change and the driver does not feel uncomfortable.

Note that Tα in FIGS. 10 (c) and 10 (d)
_1, V.alpha _1, if the range of the degree never driver feel uncomfortable with compatible and the prevention of lane departure by tolerance and doze like lane departure by the driver of the own intention, set the appropriate value FIG. 10
The setting map is not limited to the setting map shown in FIG.

Further, as described above, the control gain setting means 5C sets the gain in accordance with the allowance time, the awakening degree, the steering torque, and the steering angular velocity, and when the driver instructs the departure direction with the turn signal 30, The gain Kd is set to 0 only for the steering control torque in the designated direction, and deviation in the designated direction is permitted. As a result, the driver turns
When the instruction is made at 0, it is possible to change lanes or turn left or right without being hindered by the steering control torque Tc.

As described above, according to the present lane departure prevention device, the control gain setting means 5C allows a time until the vehicle reaches the obstacle ahead, the driver's consciousness level, the steering torque and the steering torque at which the driver steers the steering wheel. angular velocity,
The control gains Ka, Kb, Kc1, and Kc of the steering control torque Tc in accordance with the driving condition of the vehicle, such as a turn signal instruction.
Since 2, Kd can be set, accurate guidance for lane departure prevention according to the situation can be provided without hindering the steering operation by the driver's intention or giving a sense of incongruity.

The steering control torque Tc is smoothed by the low-pass filter 25 and output.
There is also an advantage that the control torque for steering generated by the steering actuator 21 can be smoothly continued without abrupt change, and the control for preventing lane departure can be stabilized. The driving condition detecting means includes the above-mentioned means, that is, the laser radar (obstacle detecting means) 29, the alertness detecting means 26, the steering torque sensor 27, the steering angle sensor 28, the turn signal 30
May not be provided with all of them, and may be provided with only a part of the means as necessary. Further, all means are provided in advance, and when unnecessary, the control gains Ka, Kb, Kc are set in the control gain setting means 5C.
1, Kc2 and Kd may be forcibly set to 1.0.

The obstacle detecting means is a laser radar 2
The camera 2 and the image information processing means 3 may be used as obstacle detection means, for example, if the obstacle can be recognized from the image information.

[0089]

As described above in detail, according to the lane departure prevention device of the present invention, when the host vehicle is about to deviate from the traveling lane, the driver's steering force is set in such a direction as to prevent this. Separately, the steering control torque is applied by the steering actuator, and the steering control torque is set to a magnitude corresponding to the amount of lateral displacement of the vehicle. Control torque can be given, and furthermore, the steering time can be adjusted according to the driving condition of the vehicle, such as the time required for the vehicle to reach the obstacle ahead, the driver's consciousness level, the steering torque at which the driver steers the steering wheel, and the steering angular velocity. The control gain of the control torque can be set, so that the steering operation by the driver's intention is not hindered or uncomfortable, It can be carried out guidance accurate lane departure prevention in accordance with the situation.

[Brief description of the drawings]

FIG. 1 is a block diagram schematically showing a configuration of a lane departure prevention device as one embodiment of the present invention.

FIG. 2 is a diagram illustrating image processing for driving lane recognition according to an embodiment of the present invention.

FIG. 3 is a schematic diagram illustrating traveling lane recognition according to an embodiment of the present invention in the order of (a) to (f).

FIG. 4 is a schematic plan view illustrating travel lane recognition.

FIG. 5 is an explanatory diagram for describing calculation of a curvature of a traveling lane.

FIG. 6 is a diagram showing an example of a map for setting a side slip prevention torque applied to the lane departure prevention device as one embodiment of the present invention.

FIG. 7 is a diagram showing another example of a map for setting a side slip prevention torque applied to the lane departure prevention device as one embodiment of the present invention.

FIG. 8 is a diagram showing an example of a map for setting a steering assist torque according to the lane departure prevention device as one embodiment of the present invention.

FIG. 9 is a diagram showing another example of a setting map of the steering assist torque according to the lane departure prevention device as one embodiment of the present invention.

FIG. 10 is a diagram showing an example of a control gain setting map according to the lane departure prevention device as one embodiment of the present invention, where (a) is a diagram showing a gain Ka setting map, and (b) is a diagram showing the gain Ka setting map.
Is a diagram showing a setting map of the gain Kb, and FIG.
FIG. 3D is a diagram showing a setting map of c1, and FIG. 4D is a diagram showing a setting map of a gain Kc2.

FIG. 11 is a flowchart illustrating an operation of the lane departure prevention device as one embodiment of the present invention.

FIG. 12 is a block diagram illustrating the operation of the lane departure prevention device as one embodiment of the present invention.

FIG. 13 is a diagram showing an example of a configuration of a steering actuator provided in the lane departure prevention device as one embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Vehicle 2 Camera 3 Image information processing means 4 Running lane estimating means 4A Side shift amount calculating means 4B Road curvature calculating means 5 Control torque calculating means 5A Control torque calculating means for side slip corresponding steering 5B Control torque correcting means 5C Control gain setting means 6 Control Means (controller) 7 Lateral acceleration calculating means 21 Steering actuator 26 Arousal level detecting means (driving situation detecting means) 27 Steering angle sensor (driving situation detecting means) 28 Steering torque sensor (driving situation detecting means) 29 Laser radar (driving situation detecting Means) 30 Turn signal 31 Lateral acceleration sensor 32 Vehicle speed sensor LC Road center line

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Takashi Ota 5-33-8 Shiba, Minato-ku, Tokyo Inside Mitsubishi Motors Corporation (56) References JP-A-7-81602 (JP, A) JP JP-A-7-47969 (JP, A) JP-A-7-104850 (JP, A) JP-A-6-255514 (JP, A) JP-A-10-194151 (JP, A) (58) Fields investigated (Int) .Cl. ⁷ , DB name) B62D 6/00

Claims (6)

(57) [Claims] The present invention provides a steering control torque of a degree that can be easily overcome by a driver in addition to a steering torque applied by a driver in a direction to prevent the vehicle from deviating from a traveling lane. A lane departure prevention device that guides prevention of lane departure of the vehicle, comprising: a lateral deviation amount calculating unit that calculates a lateral deviation amount of a traveling position of the vehicle from a reference position of the traveling lane; Control torque calculating means for calculating a control torque based on the calculated lateral displacement amount; and control for controlling the steering actuator such that the control torque calculated by the control torque calculating means is generated in a direction to reduce the lateral displacement amount. Means, and driving condition detecting means for detecting a driving condition of the vehicle, wherein the control torque calculating means detects the driving condition detected by the driving condition detecting means. Wherein the control gain setting means for setting a control gain of the control torque based on the lateral shift amount according to the operating conditions are provided, the lane departure prevention apparatus. (2) Forward of the vehicle as the driving condition detecting means
With forward obstacle detection means for detecting obstacles, The control gain setting means is configured to determine whether the vehicle is in the position of detecting the obstacle ahead of the vehicle.
When there is enough time to reach the front obstacle detected by the step
Is configured to set the control gain in accordance with
The lane departure prevention device according to claim 1, characterized in that:
Place. (3) The driver's awareness as the driving situation detecting means
Arousal level detection means for detecting arousal level is provided, The control gain setting means is detected by the alertness detecting means.
The control gain is set in accordance with the arousal level thus set.
The lane deflecting device according to claim 1, characterized in that it is formed.
Detachment prevention device. (4) As the driving condition detecting means, the driver
Equipped with a steering torque sensor that detects the steering torque The control gain setting means detects by the steering torque sensor.
The control gain is set in accordance with the output steering torque.
Claims characterized by the following: 1 described
Lane departure prevention device. (5) The steering angle is detected as the driving condition detecting means.
Steering angle sensor The control gain setting means detects the control gain detected by the steering angle sensor.
The control gain is set according to the steered angle.
The lane departure according to claim 1, wherein the lane departure is performed.
Prevention device. 6. A blinker finger as the driving condition detecting means
It has a means to detect the indicated direction, The control gain setting means responds to a direction indicated by the turn signal.
That the control gain is set by
The lane departure prevention device according to claim 1, characterized in that: