JP5424111B2 - Lane departure prevention support device - Google Patents

Description

  The present invention relates to a lane departure prevention support device, and more specifically, even when a lane marking is detected only on either the left or right side of the host vehicle, lane departure prevention support can be performed accurately. The present invention relates to a lane departure prevention support apparatus.

  In recent years, Lane Departure Warning System and Lane Keeping Assist System have been developed as automobile lane departure prevention support devices. The lane departure warning device recognizes the lane in which the host vehicle is traveling based on the image captured by the camera, determines whether or not the host vehicle departs from the lane, and issues a warning to the driver if it determines It is a device that alerts and calls attention. The lane keeping assist device recognizes the lane in which the host vehicle travels based on the image captured by the camera, determines whether or not the host vehicle departs from the lane, and determines that the host vehicle deviates, It is a device that applies steering assist torque to a handle for maintaining the vehicle in the lane. In any of the apparatuses, a lane marking represented by a white line is captured by a camera, and it is determined whether or not the host vehicle departs from the lane based on the positional relationship between the captured lane marking and the host vehicle.

  A conventional lane departure prevention support apparatus detects a lane marking on at least one of the left and right sides of the host vehicle, and assists in preventing the host vehicle from departing from the lane based on the detection result of the lane marking. If both the left and right lane lanes are detected and the distance between the lane lane on one side and the lane lane on the other side is a general distance, the detection results for both lane lanes are usually correct. There is no particular problem.

However, the conventional lane departure prevention support device has the following problems.
If a lane line is detected on either the left or right side of the host vehicle and no lane line is detected on the other side, the lane line is far away from the detected lane line. However, if it is within the imaging area of the camera, the detection operation (search) of the other lane marking has been continued. For this reason, a line that is not actually a lane line may be erroneously detected as a lane line on the other side at a position considerably away from the lane line detected on one side. For example, in the United States, a yellow line may be painted along the lane on the side wall of the roadway, and a groove may be formed along the lane on the side wall of the roadway in Europe. These yellow lines and grooves may be erroneously detected as lane markings at positions far away from the detected lane markings. Also, if there is dirt on the road surface along the lane at a position far away from the lane line detected on one side, the dirt may be erroneously detected as the lane line on the other side. . If a lane line is erroneously detected, the lane cannot be accurately recognized, and there is a problem in that lane departure prevention support cannot be performed accurately.

In Patent Document 1, even when image recognition processing cannot be performed on a part of a captured image and only one lane marker (lane marking) on the own vehicle can be detected, the lane marker on one side and the lane width (lane) A vehicle-mounted traveling environment recognition device that issues a lane departure warning based on the standard value of (width) is disclosed.
However, in the technique of Patent Document 1, no countermeasure is taken to prevent the lane marker from being erroneously detected on the other side, and the above-described problem cannot be solved.

JP 2008-197863 A

  The present invention has been made in view of such circumstances, and even when a lane marking is detected only on either the left or right side of the host vehicle, the lane departure prevention support can be accurately performed. An object of the present invention is to provide a lane departure prevention support device.

The first invention is
A lane departure prevention support device that detects lane markings on the left and right sides of the host vehicle, and supports the lane departure prevention of the host vehicle based on the detection result of the lane markings,
Imaging means for imaging the front of the host vehicle including an oblique front;
Lane lane marking detection means for detecting a lane marking based on the front image captured by the imaging means;
Based on the positional relationship between the lane markings detected by the lane marking detection means and the host vehicle, support means for supporting the lane departure prevention of the host vehicle;
Determining means for determining whether the distance between the detected lane line and the own vehicle is less than a predetermined value when the lane line is detected only on either the left or right side by the lane line detection unit; ,
When the determination means determines that the distance is less than a predetermined value, the support means is shifted from the pause mode to the supportable mode, and when the distance is determined to be greater than or equal to the predetermined value, the support means is It is a lane departure prevention assistance apparatus provided with the mode setting means maintained with a rest mode.

According to the first invention, when it is determined that the distance between the detected lane marking and the host vehicle is less than a predetermined value, the support means is shifted from the pause mode to the supportable mode, and the distance is a predetermined value. If it is determined as above, the support means is maintained in the sleep mode.
Therefore, after the lane marking is detected only on one of the left and right sides, even if the lane marking is erroneously detected on the other side, the support means remains stopped. If the lane marking is detected only on one of the left and right sides, and the determination means determines that the distance is less than the predetermined value, the other lane marking is not detected and the support means May be suspended.

According to a second invention, in the first invention,
A lane width calculating means for calculating an interval between the detected lane markings on both the left and right sides when the lane marking detection means detects the lane markings on the left and right sides of the own vehicle;
Storage means for storing the lane width calculated by the lane width calculation means;
And further comprising setting means for setting the predetermined value based on the lane width stored by the storage means when the lane marking is detected only on either the left or right side by the lane marking detection means. It is characterized by.

  According to the second invention, the predetermined value is set based on the stored lane width. For example, the predetermined value can be set large for a wide lane and the predetermined value can be set small for a narrow lane. Therefore, when a lane line is detected only on one of the left and right sides, the possibility that a lane line is erroneously detected on the other side can be reduced.

According to a third invention, in the first invention,
The lane marking detection means detects the type of the detected lane marking,
Setting means for setting the predetermined value based on the type of the lane marking detected by the lane marking detection means when the lane marking is detected only on either the left or right side by the lane marking detection means Is further provided.

  According to the third aspect, the predetermined value is set based on the type of the detected lane marking. For example, it is possible to set a large predetermined value for a normal white line having a large amount of information for lane marking detection, and to set a small predetermined value for a botsdot (smallly used mainly in the United States) having a small amount of information. Therefore, when a lane marking is detected only on one of the left and right sides, the possibility that a lane marking is erroneously detected on the other side can be reduced.

According to a fourth invention, in the first invention,
The vehicle further comprises setting means for setting the predetermined value based on noise generated in the front image of the imaging means when a lane marking is detected only on either the left or right side by the lane marking detection means. It is characterized by.

  According to the fourth invention, the predetermined value is set based on the noise generated in the front image of the imaging means. For example, when the noise is low, the predetermined value can be set large, and when the noise is high, the predetermined value can be set small. Therefore, when a lane line is detected only on one of the left and right sides, the possibility that a lane line is erroneously detected on the other side can be reduced. Note that the noise includes, for example, road surface noise that occurs when there are many dirt and patterns on the road surface, and thermal noise that increases as the temperature increases.

According to a fifth invention, in the first invention,
Curvature detection means for detecting the curvature of the lane in which the host vehicle travels;
When the lane line is detected only on either the left or right side by the lane line detection unit, the vehicle further comprises setting means for setting the predetermined value based on the curvature detected by the curvature detection unit. Features.

  According to the fifth aspect, the predetermined value is set based on the curvature of the lane in which the host vehicle is traveling. The present invention is mainly applied to a lane keeping assist device. In the lane keeping assist device, a control in which feedback control based on the offset amount of the own vehicle with respect to a predetermined position of the lane and the yaw angle of the own vehicle with respect to the lane is combined with feedforward control based on the curve curvature of the lane and the vehicle speed of the own vehicle. Is generally performed. An advantage of applying the first aspect of the present invention to the lane keeping assist device is to suppress a sudden change in the steering assist torque due to the feedback control. In a traveling situation in which the output of the feedforward control is large, the driver does not feel discomfort with respect to the torque fluctuation due to the feedback control. That is, when the front side of the host vehicle is a curved road, the driver tends not to feel uncomfortable with respect to the steering assist torque applied to the inside of the curve. For this reason, when the front is a curved road, the allowable value of torque fluctuation by feedback control becomes large. Therefore, the predetermined value can be set in consideration of the driver's uncomfortable feeling with respect to the steering assist torque. Accordingly, it is possible to perform lane maintenance support that makes it difficult for the driver to feel uncomfortable.

According to a sixth invention, in the first invention,
Vehicle speed detection means for detecting the vehicle speed of the host vehicle;
And a setting means for setting the predetermined value based on the vehicle speed detected by the vehicle speed detecting means when the lane marking is detected only on either the left or right side by the lane marking detecting means. Features.

  According to the sixth aspect, the predetermined value is set based on the vehicle speed. In the feedforward control in the lane keeping assist device, the target steering torque is generally determined based on the vehicle speed of the host vehicle. This is because the steering torque required to turn the curve is proportional to the square of the vehicle speed. Therefore, by appropriately setting the predetermined value based on the vehicle speed, it is possible to perform lane maintenance support that makes it difficult for the driver to feel uncomfortable.

According to a seventh invention, in the first invention,
The support means includes steering assist means for applying assist torque to the steering mechanism so that the host vehicle travels a predetermined position in the lane,
The steering assist means is
Feedforward gain calculating means for calculating a feedforward control gain based on the curve radius of the traveling lane of the host vehicle;
Feedback gain calculation means for calculating a feedback control gain based on a yaw angle formed by the host vehicle with respect to the travel lane and an offset amount of the host vehicle with respect to a predetermined position of the travel lane;
An auxiliary torque calculating means for calculating a target auxiliary torque based on the feedforward control gain and the feedback control gain;
Torque applying means for applying auxiliary torque to the steering mechanism based on the target auxiliary torque calculated by the auxiliary torque calculating means;
The lane departure prevention support device is
It further comprises setting means for setting the predetermined value based on the feedforward control gain when a lane line is detected only on either the left or right side by the lane line detection means.

  According to the seventh aspect, the predetermined value is set based on the feedforward control gain. The feedforward control gain can be made constant, but can also be made variable based on the driving situation. For example, the control gain can be changed according to the type of the detected lane marking. By appropriately setting the predetermined value based on the feedforward control gain, it is possible to perform lane keeping support that makes it difficult for the driver to feel uncomfortable.

  Even when a lane marking can be detected only on either the left or right side of the host vehicle, lane departure prevention support can be performed accurately.

The block diagram which shows the lane departure prevention assistance apparatus which concerns on 1st Embodiment of this invention. The figure which shows the space | interval of a lane line and the own vehicle at the time of detecting a lane line only to either the right or left side of the own vehicle The figure which shows the space | interval of a lane line and the own vehicle at the time of detecting a lane line on the both right and left sides of the own vehicle The flowchart which shows operation | movement of the lane departure prevention assistance apparatus shown by FIG. The block diagram which shows the lane departure prevention assistance apparatus which concerns on 2nd Embodiment of this invention. The figure which shows the distance of the own vehicle and one lane in the narrow lane and the wide lane The block diagram which shows the lane departure prevention assistance apparatus which concerns on 3rd Embodiment of this invention. The block diagram which shows the lane departure prevention assistance apparatus which concerns on 4th Embodiment of this invention. Graph showing the relationship between the amount of noise and the first threshold The block diagram which shows the lane departure prevention assistance apparatus which concerns on 5th Embodiment of this invention. Diagram showing steering force assist control system The figure which shows the relationship between curve curvature and predetermined value The block diagram which shows the lane departure prevention assistance apparatus which concerns on 6th Embodiment of this invention. The block diagram which shows the lane departure prevention assistance apparatus which concerns on 7th Embodiment of this invention.

(First embodiment)
A first embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing a lane departure prevention support apparatus according to a first embodiment of the present invention. FIG. 2 is a diagram illustrating the distance between the lane marking and the host vehicle when the lane marking is detected on both the left and right sides of the host vehicle. FIG. 3 is a diagram illustrating the distance between the lane line and the host vehicle when the lane line is detected only on either the left or right side of the host vehicle. FIG. 4 is a flowchart showing the operation of the lane departure prevention support apparatus shown in FIG.

  The lane departure prevention apparatus 1 according to the first embodiment is an apparatus that detects lane markings 2 on both the left and right sides of the host vehicle 3 and supports the lane departure prevention of the host vehicle 3 based on the detection result of the lane markings 2. is there. The concept of the lane departure prevention support device 1 includes a lane departure warning device and a lane maintenance support device. The lane departure warning device recognizes the lane in which the host vehicle is traveling based on the captured image of the camera, determines whether the host vehicle departs from the lane, and warns the driver when it is determined to depart. It is a device that alerts and calls attention. The lane keeping assist device recognizes the lane in which the host vehicle travels based on the captured image of the camera, determines whether the host vehicle departs from the lane, and determines that the host vehicle deviates, This is a device that applies a steering assist torque to the electric power steering mechanism for maintaining the vehicle in the lane.

  The lane departure prevention apparatus 1 includes an imaging unit 4, a lane marking detection unit 5, a support unit 6, a determination unit 7, and a mode setting unit 8. The lane line detection means 5, the determination means 7, and the mode setting means 8 are functional blocks included in the ECU 100.

  The ECU 100 includes a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and the like. Each function block shown in FIG. 1 operates when the CPU executes a program stored in the ROM. The CPU uses the RAM as a work area during execution of the program.

  The imaging means 4 images the front road surface including the diagonally front of the host vehicle 3. The imaging means 4 is, for example, a CCD camera or a CMOS camera. As shown in FIGS. 2 and 3, the imaging area W of the imaging means 4 has a fan shape. When there are lane markings 2 on both the left and right sides of the host vehicle 3, the lane markings 2 on both sides enter the imaging region W as shown in FIG. The width of the imaging region W is set larger than the interval between the lane markings 2 on both sides.

  The lane line detection unit 5 detects the lane line 2 based on the front image captured by the imaging unit 4. The “lane line” in the present embodiment is a line that defines the travel lane of the vehicle on the road surface, and includes what is generally referred to as a road center line, a road boundary line, a road outer line, and the like. As a form of a lane line, the travel lane line represented by the white line, the road fence, a yellow line, a stone, etc. is included, for example. The white line also has a plurality of forms, for example, a long continuous white line, a white line in which a line of degrees is intermittent as 10 to 10 meters, a white line in which round dots are dotted lines (mainly used in the United States, Called).

  The support means 6 supports the lane departure prevention of the host vehicle 3 based on the positional relationship between the lane marking 2 and the host vehicle 3 detected by the lane marking detection means 5. As a form of support, as described above, when it is determined that the host vehicle 3 departs from the driving lane, a warning is issued to the driver to call attention, and it is determined that the host vehicle 3 departs from the driving lane. In this case, a steering assist torque for maintaining the position of the host vehicle 3 in the lane is applied to the electric power steering mechanism.

When the lane line 2 is detected only on the left or right side of the host vehicle 3 by the lane line detector 5, the determination unit 7 determines that the interval between the detected lane line 2 and the host vehicle 3 is first. It is determined whether it is less than one threshold value α. The first threshold value α corresponds to a “predetermined value” in the claims. The value of the first threshold value α is set to a value that is unlikely to cause erroneous detection of the lane marking 2 on the other side of the host vehicle 3. The value of the first threshold value α is not particularly limited, but is set to 3.5 m, for example. In addition, when the lane line 2 is detected only on the left or right side of the host vehicle 3 by the lane line detector 5, the determination unit 7 determines the interval between the detected lane line 2 and the host vehicle 3. Is greater than or equal to the second threshold value β. The second threshold value β is that the driver feels uncomfortable even if an alarm sounds when the driver turns off the turn signal indicator and then turns off the vehicle 3 before reaching the lane line 2. It is set to a value that does not exist. The second threshold value β is a direction in which the lane change is to be made when the driver performs an OFF operation before the host vehicle 3 reaches the lane marking 2 after the driver performs an ON operation of the direction indicator. Even if the steering assist torque is applied in the opposite direction, the value is set so that the driver does not feel uncomfortable. The value of the second threshold value β is not particularly limited, but is set to 0.2 m, for example.
Further, when the lane marking 2 is detected on the left and right sides of the own vehicle 3 by the lane marking detection means 5, the determination means 7 determines that the interval between the detected lane marking 2 and the own vehicle 3 is the second threshold β It is determined whether it is above.

The mode setting means 8 performs the following operation when the lane marking 2 is detected only on the left or right side of the host vehicle 3 by the lane marking detection means 5. That is, the mode setting means 8 determines that the interval D (DL or DR, see FIG. 2) between the detected lane marking 2 and the host vehicle 3 is less than the first threshold value α by the determination means 7, and When the determination unit 7 determines that the interval D is equal to or greater than the second threshold value β, the support unit 6 is shifted from the pause mode to the supportable mode. Further, the mode setting means 8 determines that the interval D (DL or DR, see FIG. 2) between the detected lane marking 2 and the host vehicle 3 is greater than or equal to the first threshold value α by the determination means 7, or If the distance D is determined by the determination means 7 to be less than the second threshold value β, the support means 6 is maintained in the pause mode.
The mode setting means 8 performs the following operation when the lane marking 2 is detected on both the left and right sides of the host vehicle 3 by the lane marking detection means 5. That is, the mode setting means 8 pauses the support means 6 when it is determined that the distance D (DL and DR, see FIG. 3) between the left and right lane markings 2 and the host vehicle 3 is greater than or equal to the second threshold value β. Transition from mode to supportable mode. Further, when it is determined that the distance D between the lane marking 2 on the left and / or right side and the host vehicle 3 is less than the second threshold value β, the mode setting unit 8 maintains the support unit 6 in the pause mode. .

Next, the characteristic operation of the lane departure prevention apparatus 1 will be described with reference to the flowchart of FIG.
As a step before entering the processing flow of FIG. 4, when the driver's intention to change the lane is confirmed by turning on the direction indicator, the lane departure prevention support device is set to the “pause mode”. Then, it is assumed that the turn indicator is turned off before the host vehicle 3 reaches the lane marking 2. Depending on the state of the vehicle when the turning operation of the direction indicator is performed, it is determined whether to shift from the “pause mode” to the “supportable mode” or to maintain the “pause mode”. The case where the mode changes will be described below. When the turn signal is turned off after the host vehicle 3 reaches the lane marking 2, the “pause mode” is maintained.

  First, it is determined whether left and right lane markings 2 have been detected (step S1). At this point, the support means 6 is in a pause mode. If it is determined in step S1 that the left and right lane markings 2 (2L, 2R) have been detected, whether or not the distance DR between the right lane marking 2R and the host vehicle 3 is greater than or equal to the second threshold β. Determination is made (step S2). On the other hand, if it is determined in step S1 that the left and right lane line 2 (2L, 2R) has not been detected, that is, either the left or right lane line 2 has been detected, or the left or right lane line If the line 2 is not detected, the process proceeds to step 7.

  If it is determined in step S2 that the interval DR is less than the second threshold value β, the positional relationship between the right lane marking 2R and the host vehicle 3 is determined to be inappropriate for the lane departure prevention support, and the sleep mode Is maintained (step S3). On the other hand, if it is determined in step S2 that the interval DR is greater than or equal to the second threshold β, it is determined whether or not the interval DL between the left lane marking 2L and the host vehicle 3 is greater than or equal to the second threshold β. (Step S4).

  When it is determined in step S4 that the interval DR is less than the second threshold value β, it is determined that the positional relationship between the left lane marking 2L and the host vehicle 3 is not appropriate for lane departure prevention support, and the sleep mode Is maintained (step S3). On the other hand, if it is determined in step S4 that the interval DL is greater than or equal to the second threshold value β, the positional relationship between the left lane marking 2L and the host vehicle 3 is determined to be appropriate for lane departure prevention support ( In step S5), the mode is shifted from the pause mode to the supportable mode (step S6). In the supportable mode, it is determined whether or not the host vehicle 3 departs from the traveling lane. When it is determined that the host vehicle 3 departs from the travel lane, the support means 6 alerts the driver to alert the driver or keeps the position of the host vehicle 3 in the travel lane, although not shown. Lane departure prevention operation such as applying steering assist torque for the purpose is performed.

  In step S1, the left and right lane markings 2 (2L, 2R) were not detected (that is, either the left or right lane marking 2 was detected, or the left or right lane marking 2 was detected). If it is determined that the left lane marking 2L has been detected (step S7). If it is determined that the left lane line 2L has been detected, it is determined whether the distance DL between the left lane line 2L and the host vehicle 3 is equal to or greater than the second threshold value β (step S8).

  If it is determined in step S8 that the distance DL is less than the second threshold value β, the positional relationship between the left lane marking 2L and the host vehicle 3 is determined not to be appropriate for lane departure prevention support, and the sleep mode Is maintained (step S3). On the other hand, if it is determined in step S8 that the distance DL is greater than or equal to the second threshold value β, it is determined whether or not the distance DL between the left lane marking 2L and the host vehicle 3 is less than the first threshold value α. (Step S9).

  If it is determined in step S9 that the distance DL is greater than or equal to the first threshold value α, it is determined that the positional relationship between the left lane marking 2L and the host vehicle 3 is not appropriate for the lane departure prevention support, and the pause mode Is maintained (step S3). On the other hand, when it is determined in step S8 that the distance DL is less than the first threshold value α, the positional relationship between the left lane marking 2L and the host vehicle 3 is determined to be appropriate for the lane departure prevention support ( Step S5), the mode is shifted from the pause mode to the supportable mode (step S6).

  If it is determined in step S7 that the left lane line 2L has not been detected, it is determined whether or not the right lane line 2R has been detected (step S10). If it is determined in step S10 that the right lane marking 2R has not been detected, it is determined that the lane departure prevention support is not appropriate and the pause mode is maintained (step S3). On the other hand, if it is determined in step S10 that the right lane line 2R has been detected, it is determined whether or not the distance DR between the right lane line 2R and the host vehicle 3 is equal to or greater than a second threshold value β ( Step S11). If it is determined in step S11 that the distance DR is less than the second threshold value β, it is determined that the distance DR is not appropriate for the lane departure prevention support, and the pause mode is maintained (step S3). On the other hand, if it is determined in step S11 that the distance DR is greater than or equal to the second threshold β, it is determined whether or not the distance DR between the right lane marking 2R and the host vehicle 3 is less than the first threshold α. (Step S12).

  If it is determined in step S12 that the interval DR is greater than or equal to the first threshold value α, it is determined that the interval DR is not appropriate for the lane departure prevention support, and the pause mode is maintained (step S3). On the other hand, if it is determined in step S12 that the interval DR is less than the first threshold value α, the positional relationship between the right lane marking 2R and the host vehicle 3 is determined to be appropriate for lane departure prevention support ( In step S5), the mode is shifted from the pause mode to the supportable mode (step S6). As described above, in the supportable mode, when it is determined that the host vehicle 3 departs from the driving lane, the support unit 6 alerts the driver to call attention, or travels in the position of the host vehicle 3. A lane departure prevention operation such as applying a steering assist torque for maintaining in the lane is performed. The above is the characteristic operation of the lane departure prevention apparatus 1.

According to the lane departure prevention support apparatus 1, in a situation where the lane marking 2 is detected only on either the left or right side of the host vehicle 3, the distance D between the lane marking 2 and the host vehicle 3 is the first threshold value α. When it is determined that the distance is less than the threshold value, the support unit 6 is shifted from the pause mode to the supportable mode, and when it is determined that the interval D is equal to or greater than the first threshold value α, the support unit 6 is maintained in the pause mode.
Therefore, when the lane marking 2 is detected only on one of the left and right sides, the support means 6 remains stopped even if the lane marking 2 is erroneously recognized on the other side. If the lane marking 2 is detected only on either the left or right side, and the determination means 7 determines that the distance D is less than the first threshold value α, the other lane marking 2 is not detected. In this way, the support means 6 may be left paused.

(Second Embodiment)
A second embodiment of the present invention will be described with reference to the drawings. FIG. 5 is a block diagram showing a lane departure prevention support apparatus according to the second embodiment. In addition, about the structure similar to 1st Embodiment, the same referential mark as 1st Embodiment is attached | subjected and the description is abbreviate | omitted.

  The lane departure prevention support apparatus 9 according to the second embodiment is different from the first embodiment in that it includes a lane width calculation means 10, a storage means 11, and a setting means 12, and other configurations. Is the same as in the first embodiment.

  When the lane line detection unit 5 detects the lane line 2 (2L, 2R) on both the left and right sides of the host vehicle 3, the lane width calculation unit 10 detects the detected lane line 2 (2L, 2R) on both the left and right sides. The interval is calculated.

  The storage unit 11 stores the lane width calculated by the lane width calculation unit 10.

  The setting means 12 sets the first threshold value α based on the lane width stored by the storage means 11 when the lane marking 2 is detected only on either the left or right side by the lane marking detection means 5.

  FIG. 6 is a diagram showing the distance between the vehicle 3 and the lane marking 2 on one side in a narrow lane and a wide lane. FIG. 6 shows the case where the left lane line 2L has disappeared due to a part of the lane line 2L on the left side of the host vehicle 3 becoming thin in the narrow lane and the wide lane, respectively. It is assumed that a part of 2L does not exist from the beginning.

  According to the lane departure prevention support device 9, the first threshold value α is set based on the stored lane width. For example, as shown in FIG. 6, the first threshold value α is set small for a narrow lane (lane width 3.0 m) (α = 2.0 (m)), and a wide lane (lane width 4). .0 m), the first threshold value α is set large (α = 3.0 (m)). Therefore, when the lane marking 2 is detected only on either the left or right side, the possibility that the other lane marking 2 is erroneously detected can be reduced.

(Third embodiment)
A third embodiment of the present invention will be described with reference to the drawings. FIG. 7 is a block diagram showing a lane departure prevention support apparatus according to the third embodiment. In addition, about the structure similar to 1st Embodiment, the same referential mark as 1st Embodiment is attached | subjected and the description is abbreviate | omitted.

The lane line detection means 14 in the lane departure prevention support apparatus 13 according to the third embodiment detects the presence and position of the lane line 2 and detects the type of the lane line 2.
The lane departure prevention support device 13 includes a setting unit 15. The setting means 15 sets the first threshold value α based on the type of the detected lane marking 2 when the lane marking 2 is detected only on either the left or right side by the lane marking detection means 14. Other configurations are the same as those of the first embodiment.

  The lane marking 2 includes a solid line, a broken line, a botsdot, and a cat's eye. When recognizing these lane markings 2 from the camera image, the stability of the recognition output is, in descending order, solid line, broken line, botsdots, and cat's eye. This is because the information amount of lane markings (lane markers) decreases in the order of solid line, broken line, botsdots, and cat's eye.

  According to the lane departure prevention support device 13, the first threshold value α is set based on the type of the detected lane marking 2. For example, for a normal white line with a large amount of information for lane line detection (division line recognition), the first threshold value α is set large (for example, α = 4.5 (m)), and a botsdot with a small amount of information (mainly, The first threshold value α can be set small (for example, α = 3 (m)). Therefore, when the lane marking 2 is detected only on either the left or right side, the possibility that the lane marking 2 is erroneously detected on the other side can be further reduced.

(Fourth embodiment)
A fourth embodiment of the present invention will be described with reference to the drawings. FIG. 8 is a block diagram showing a lane departure prevention support apparatus according to the fourth embodiment. FIG. 9 is a graph showing the relationship between the noise amount and the first threshold value α. In addition, about the structure similar to 1st Embodiment, the same referential mark as 1st Embodiment is attached | subjected and the description is abbreviate | omitted.

  The lane departure prevention support apparatus 16 according to the fourth embodiment is different from the first embodiment in that the setting means 17 is provided, and other configurations are the same as those in the first embodiment.

  The setting means 17 sets the first threshold value α based on the amount of noise generated in the front image of the imaging means 4 when the lane marking 2 is detected only on either the left or right side by the lane marking detection means 5. Set. For example, as shown in FIG. 9, the first threshold value α is set large when the amount of noise is small, and the first threshold value α is set small when the amount of noise is large. Note that the noise includes, for example, road surface noise that occurs when there are many dirt and patterns on the road surface, and thermal noise that increases as the temperature increases.

  As the amount of noise on the captured image of the imaging means 4 increases, erroneous detection is more likely to occur due to the detection logic principle of the lane marking 2. Therefore, as described above, the false detection can be effectively suppressed by setting the first threshold value α smaller as the amount of noise increases. The detection logic principle will be briefly described. After extracting a point where the luminance value greatly changes on the captured image of the road surface as an edge point, a white line is detected by linearly approximating the edge point.

  According to the lane departure prevention support device 16, the first threshold value α is set based on the amount of noise generated in the front image of the imaging unit 4. Therefore, when the lane marking 2 is detected only on either the left or right side, the possibility that the lane marking 2 is erroneously detected on the other side can be reduced.

(Fifth embodiment)
A fifth embodiment of the present invention will be described with reference to the drawings. FIG. 10 is a block diagram showing a lane departure prevention support apparatus according to the fifth embodiment of the present invention. FIG. 11 is a diagram showing a steering force assist control system. FIG. 12 is a diagram illustrating the relationship between the curve curvature and the first threshold value α. In addition, about the structure similar to 1st Embodiment, the same referential mark as 1st Embodiment is attached | subjected and the description is abbreviate | omitted.

  The lane departure prevention support apparatus 18 according to the fifth embodiment is different from the first embodiment in that it includes a curvature detection means 19, a setting means 20, and a vehicle speed detection means 22, and the other configurations are the first implementation. It is the same as the form. The lane departure prevention support device 18 mainly functions as a lane maintenance support device.

  The curvature detection means 19 detects the curvature of the lane in which the host vehicle 3 travels.

  The vehicle speed detection means 22 detects the vehicle speed of the host vehicle 3.

  The setting means 20 sets the first threshold value α based on the curvature detected by the curvature detection means 19 when the lane marking is detected only on either the left or right side by the lane marking detection means.

  According to the lane departure prevention support device 18, the first threshold value α is set based on the curvature of the lane in which the host vehicle 3 travels. In general, as shown in FIG. 11, in the lane keeping assist device, feedback control with respect to the offset amount of the own vehicle with respect to a predetermined position of the lane and the yaw angle of the own vehicle based on the lane, the curve curvature of the lane, and the vehicle speed of the own vehicle 3. Control in combination with feedforward control based on is performed. One of the advantages of applying the invention according to the first embodiment to a lane keeping assist device is to suppress sudden steering assist torque fluctuations due to feedback control. When the driving situation in which the output of the feedforward control increases, that is, when the front of the host vehicle is a curved road, the degree of torque fluctuation due to feedback control is relatively small, and the driver does not feel uncomfortable with the torque fluctuation due to feedback control. . For this reason, when the front is a curved road, the allowable value of torque fluctuation by feedback control becomes large. Therefore, the first threshold value α can be set in consideration of the driver's uncomfortable feeling with respect to the steering assist torque. Specifically, as shown in FIG. 12, when the curve curvature of the travel lane is large, the first threshold value α is set large, and when the curve curvature of the travel lane is small, the first threshold value α is set small. . Accordingly, it is possible to perform lane maintenance support that makes it difficult for the driver to feel uncomfortable.

(Sixth embodiment)
A sixth embodiment of the present invention will be described with reference to the drawings. FIG. 13 is a block diagram showing a lane departure prevention support apparatus according to the sixth embodiment of the present invention. In addition, about the structure similar to 1st Embodiment, the same referential mark as 1st Embodiment is attached | subjected and the description is abbreviate | omitted.

  The lane departure prevention support apparatus 21 according to the sixth embodiment is different from the first embodiment in that the vehicle speed detection means 22 and the setting means 23 are provided, and other configurations are the same as those in the first embodiment. Note that the lane departure prevention support device 21 mainly functions as a lane keeping support device.

  The vehicle speed detection means 22 detects the vehicle speed of the host vehicle 3.

  When the lane line 2 is detected only on the left or right side of the host vehicle 3 by the lane line detection unit 5, the setting unit 23 uses the first threshold value α based on the vehicle speed detected by the vehicle speed detection unit 22. Set.

  According to the lane departure prevention support device 21, the first threshold value α is set based on the vehicle speed. In general, the feedforward control in the lane keeping assist device determines a target steering torque based on the vehicle speed of the host vehicle. The steering torque required to turn the curve is proportional to the square of the vehicle speed. Therefore, by appropriately setting the first threshold value α based on the vehicle speed, it is possible to perform lane keeping support that makes it difficult for the driver to feel uncomfortable.

(Seventh embodiment)
A seventh embodiment of the present invention will be described with reference to the drawings. FIG. 14 is a block diagram showing a lane departure prevention support apparatus according to the seventh embodiment of the present invention. The lane departure prevention support device 24 mainly functions as a lane maintenance support device. About the structure similar to 1st Embodiment, the same referential mark as 1st Embodiment is attached | subjected and the description is abbreviate | omitted. Note that FIG. 11 is referred to as a diagram showing a control system of the steering force assist.

  The lane departure prevention support apparatus 24 according to the seventh embodiment is different from the first embodiment in that the support means 25 is provided instead of the support means 6 and the setting means 32 is provided, and other configurations are the first embodiment. It is the same.

  The support unit 25 includes a steering assist unit 26 that applies an assist torque to the steering mechanism so that the host vehicle 3 travels a predetermined position in the lane.

  As shown in FIG. 11, the steering assist unit 26 includes a feed forward gain calculation unit 28, a feedback gain calculation unit 29, a target torque calculation unit 30, and a torque application unit 31.

  The feedforward gain calculating means 28 calculates a feedforward control gain based on the curve radius of the traveling lane of the host vehicle 3 and the vehicle speed.

  The feedback gain calculation means 29 calculates a feedback control gain based on the yaw angle formed by the host vehicle 3 with respect to the travel lane and the offset amount of the host vehicle 3 with respect to a predetermined position on the travel lane.

  The control torque calculation means 30 calculates a target control torque based on the calculated feedforward control gain and feedback control gain.

  The torque applying means 31 applies steering assist torque to the steering mechanism based on the target torque calculated by the control torque calculating means 30.

  The setting unit 32 sets the first threshold value α based on the feedforward control gain when the lane line 2 is detected only on the left or right side of the host vehicle 3 by the lane line detection unit 5.

  According to the lane departure prevention support device 24, the first threshold value α is set based on the feedforward control gain. The feedforward control gain can be made constant, but can also be made variable based on the driving situation. For example, the feedforward control gain can be changed according to the type of the detected lane marking 2. By appropriately setting the first threshold value α based on the feedforward control gain, it is possible to perform lane keeping support that makes it difficult for the driver to feel uncomfortable.

  INDUSTRIAL APPLICABILITY The present invention can be used for a lane departure prevention support device that performs a lane departure warning or performs steering force assist so as to travel while maintaining a lane.

1, 9, 13, 16, 18, 21, 24 Lane departure prevention support device 2 Lane lane 2A Lane on the left side of the vehicle 2A Lane lane on the right side of the vehicle 3A vehicle lane 3 5, 14 Lane marking line detection means 6, 25 Support means 7 Determination means 8 Mode setting means 10 Lane width detection means 11 Storage means 12, 15, 17, 20, 23, 32 Setting means (threshold α)
19 Curvature detecting means 22 Vehicle speed detecting means 26 Steering assist means 28 Feed forward gain calculating means 29 Feedback gain calculating means 30 Control torque calculating means 31 Torque applying means 100 ECU

Claims (5)

A lane departure prevention support device that detects lane markings on the left and right sides of the host vehicle, and supports the lane departure prevention of the host vehicle based on the detection result of the lane markings,
Imaging means for imaging the front of the host vehicle including an oblique front;
Lane lane marking detection means for detecting a lane marking based on the front image captured by the imaging means;
Based on the positional relationship between the lane line detected by the lane line detection unit and the own vehicle, support means for supporting the lane departure prevention of the own vehicle;
A determination unit that determines whether a distance between the detected lane line and the host vehicle is less than a predetermined value when the lane line is detected on only one of the left and right sides by the lane line detection unit; ,
When the determination means determines that the distance is less than a predetermined value, the support means is shifted from the sleep mode to the supportable mode, and when the distance is determined to be greater than or equal to a predetermined value, the support means is Mode setting means for maintaining the sleep mode ,
The lane marking detection means detects the type of the detected lane marking,
Setting means for setting the predetermined value based on the type of the lane line detected by the lane line detection means when the lane line is detected only on either the left or right side by the lane line detection means A lane departure prevention support device further comprising: A lane departure prevention support device that detects lane markings on the left and right sides of the host vehicle, and supports the lane departure prevention of the host vehicle based on the detection result of the lane markings,
Imaging means for imaging the front of the host vehicle including an oblique front;
Lane lane marking detection means for detecting a lane marking based on the front image captured by the imaging means;
Based on the positional relationship between the lane line detected by the lane line detection unit and the own vehicle, support means for supporting the lane departure prevention of the own vehicle;
A determination unit that determines whether a distance between the detected lane line and the host vehicle is less than a predetermined value when the lane line is detected on only one of the left and right sides by the lane line detection unit; ,
When the determination means determines that the distance is less than a predetermined value, the support means is shifted from the sleep mode to the supportable mode, and when the distance is determined to be greater than or equal to a predetermined value, the support means is Mode setting means for maintaining the sleep mode;
Setting means for setting the predetermined value based on noise generated in a front image of the imaging means when a lane marking is detected only on either the left or right side by the lane marking detection means; Lane departure prevention support device. A lane departure prevention support device that detects lane markings on the left and right sides of the host vehicle, and supports the lane departure prevention of the host vehicle based on the detection result of the lane markings,
Imaging means for imaging the front of the host vehicle including an oblique front;
Lane lane marking detection means for detecting a lane marking based on the front image captured by the imaging means;
Based on the positional relationship between the lane line detected by the lane line detection unit and the own vehicle, support means for supporting the lane departure prevention of the own vehicle;
A determination unit that determines whether a distance between the detected lane line and the host vehicle is less than a predetermined value when the lane line is detected on only one of the left and right sides by the lane line detection unit; ,
When the determination means determines that the distance is less than a predetermined value, the support means is shifted from the sleep mode to the supportable mode, and when the distance is determined to be greater than or equal to a predetermined value, the support means is Mode setting means for maintaining the sleep mode;
Curvature detection means for detecting the curvature of the lane in which the host vehicle travels;
A lane comprising setting means for setting the predetermined value based on the curvature detected by the curvature detection means when the lane marking is detected only on either the left or right side by the lane marking detection means; Deviation prevention support device. A lane departure prevention support device that detects lane markings on the left and right sides of the host vehicle, and supports the lane departure prevention of the host vehicle based on the detection result of the lane markings,
Imaging means for imaging the front of the host vehicle including an oblique front;
Lane lane marking detection means for detecting a lane marking based on the front image captured by the imaging means;
Based on the positional relationship between the lane line detected by the lane line detection unit and the own vehicle, support means for supporting the lane departure prevention of the own vehicle;
A determination unit that determines whether a distance between the detected lane line and the host vehicle is less than a predetermined value when the lane line is detected on only one of the left and right sides by the lane line detection unit; ,
When the determination means determines that the distance is less than a predetermined value, the support means is shifted from the sleep mode to the supportable mode, and when the distance is determined to be greater than or equal to a predetermined value, the support means is Mode setting means for maintaining the sleep mode;
Vehicle speed detection means for detecting the vehicle speed of the host vehicle;
A lane comprising setting means for setting the predetermined value based on the vehicle speed detected by the vehicle speed detection means when a lane marking is detected only on either the left or right side by the lane marking detection means; Deviation prevention support device. A lane departure prevention support device that detects lane markings on the left and right sides of the host vehicle, and supports the lane departure prevention of the host vehicle based on the detection result of the lane markings,
Imaging means for imaging the front of the host vehicle including an oblique front;
Lane lane marking detection means for detecting a lane marking based on the front image captured by the imaging means;
Based on the positional relationship between the lane line detected by the lane line detection unit and the own vehicle, support means for supporting the lane departure prevention of the own vehicle;
A determination unit that determines whether a distance between the detected lane line and the host vehicle is less than a predetermined value when the lane line is detected on only one of the left and right sides by the lane line detection unit; ,
When the determination means determines that the distance is less than a predetermined value, the support means is shifted from the sleep mode to the supportable mode, and when the distance is determined to be greater than or equal to a predetermined value, the support means is Mode setting means for maintaining the sleep mode,
The support means includes steering assist means for applying an assist torque to the steering mechanism so that the host vehicle travels a predetermined position in the lane,
The steering assist means includes
Feedforward gain calculating means for calculating a feedforward control gain based on the curve radius of the traveling lane of the host vehicle;
Feedback gain calculation means for calculating a feedback control gain based on a yaw angle formed by the host vehicle with respect to the travel lane and an offset amount of the host vehicle with respect to a predetermined position of the travel lane;
An auxiliary torque calculating means for calculating a target auxiliary torque based on the feedforward control gain and the feedback control gain;
Torque application means for applying auxiliary torque to the steering mechanism based on the target auxiliary torque calculated by the auxiliary torque calculation means;
The lane departure prevention support device includes:
A lane departure prevention support apparatus further comprising setting means for setting the predetermined value based on the feedforward control gain when a lane line is detected only on either the left or right side by the lane line detection unit. .

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