JP4062330B2 - Lane departure prevention device - Google Patents

Description

  The present invention relates to a lane departure prevention apparatus for preventing a departure of a host vehicle from a traveling lane.

Conventionally, as this kind of lane departure prevention device, for example, when the host vehicle tends to deviate from the traveling lane, the steering actuator is controlled so as to avoid the departure from the traveling lane of the own vehicle. Some prevent lane departures.
In such a lane departure prevention device, an image in front of the host vehicle is usually captured by an in-vehicle camera, and a lane marking such as a road white line is detected from the captured image, thereby tending to deviate from the traveling lane. This is detected (for example, see Patent Document 1).
JP-A-9-349833

However, in the above conventional lane departure prevention device, the lane marking is detected from the captured image of the in-vehicle camera. For example, when the sight is not good due to fog, rain, etc., the host vehicle travels. The tendency to deviate from the lane cannot be detected, and as a result, the lane departure avoidance performance may be deteriorated.
The present invention has been made for the purpose of solving the unsolved problems of the conventional lane departure prevention device described above, and provides a traveling lane departure prevention device capable of improving lane departure avoidance performance when the line of sight is not good. This is the issue.

  In order to solve the above-described problem, the lane departure prevention apparatus according to the present invention detects a lane division line from an image ahead of the host vehicle, and detects that the host vehicle tends to depart from the traveling lane based on the detection result. Sometimes, in a lane departure prevention apparatus that performs lane departure avoidance control for avoiding a departure from the traveling lane of the host vehicle, when the lane marking cannot be detected from the image, the host vehicle is provided in the vicinity of the lane marking or on the lane marking. When it is detected that the vehicle is traveling on the uneven road surface, vehicle control is performed so that the host vehicle is directed to the center position of the traveling lane.

  Therefore, in the lane departure prevention apparatus according to the present invention, for example, even when the line of sight is not good due to fog or rain, the vehicle control is performed when the vehicle travels on the road surface unevenness. As a result, the lane departure avoidance performance when the line of sight is not good can be improved.

Hereinafter, an example in which the lane departure prevention apparatus of the present invention is applied to a rear wheel drive vehicle equipped with an automatic transmission and a conventional differential gear, and with a braking device capable of independently controlling the braking force of the left and right wheels for both the front and rear wheels. This will be described with reference to the attached drawings.
FIG. 1 is a schematic configuration diagram showing a first embodiment of a lane departure prevention apparatus according to the present invention.
In the figure, reference numeral 1 is a brake pedal, 2 is a booster, 3 is a master cylinder, and 4 is a reservoir. Normally, the brake fluid pressure increased by the master cylinder 3 in accordance with the amount of depression of the brake pedal 1 by the driver. Is supplied to the wheel cylinders 6FL to 6RR of the wheels 5FL to 5RR. A braking fluid pressure control circuit 7 is interposed between the master cylinder 3 and each wheel cylinder 6FL-6RR. Can be controlled individually.

  The brake fluid pressure control circuit 7 uses, for example, a brake fluid pressure control circuit used for anti-skid control or traction control, and can independently control the brake fluid pressure of each of the wheel cylinders 6FL to 6RR. Although it is possible, when a braking fluid pressure command value is input from a braking / driving force control unit 8 described later, the braking fluid pressure is controlled according to the braking fluid pressure command value.

  Further, in this vehicle, driving torque to the rear wheels 5RL and 5RR which are driving wheels is controlled by controlling the operating state of the engine 9, the selected transmission ratio of the automatic transmission 10, and the throttle opening of the throttle valve 11. A drive torque control unit 12 is provided for control. The operating state of the engine 9 can be controlled by controlling the fuel injection amount and the ignition timing, and can also be controlled by simultaneously controlling the throttle opening. The drive torque control unit 12 can independently control the drive torque of the drive wheels 5RL and 5RR, but when the drive torque command value is input from the braking / driving force control unit 8, the drive torque control unit 12 drives the drive torque. Drive wheel torque is controlled according to the torque command value.

  Further, this vehicle is provided with a CCD camera 13 and a camera controller 14 for detecting the position of the host vehicle in the traveling lane for detecting the lane departure tendency of the host vehicle. The camera controller 14 detects, for example, a road white line that is a lane marking line from the captured image captured by the CCD camera 13 and detects a travel lane, and the travel lane and the longitudinal axis of the own vehicle. And the lateral displacement X from the center of the traveling lane, the traveling lane curvature β, and the like are calculated. If the travel lane cannot be detected, the angle φ between the travel lane and the longitudinal axis of the host vehicle, the lateral displacement X from the center of the travel lane, and the travel lane curvature β are set to “0”.

  The vehicle also includes an acceleration sensor 15 that detects longitudinal acceleration Xg and lateral acceleration Yg generated in the host vehicle, a yaw rate sensor 16 that detects yaw rate φ ′ generated in the host vehicle, an output pressure of the master cylinder 3, so-called master. A master cylinder pressure sensor 17 that detects the cylinder pressure Pm, an accelerator pedal depression amount, that is, an accelerator opening sensor 18 that detects the accelerator opening Acc, a steering angle sensor 19 that detects the steering angle δ of the steering wheel 21, and each wheel 5FL Are provided with wheel speed sensors 22FL to 22RR for detecting a rotational speed of 5RR, so-called wheel speed Vwi (i = FL to RR), and a direction indicating switch 20 for detecting a direction indicating operation by a direction indicator. It is output to the braking / driving force control unit 8.

Further, the angle φ formed between the traveling lane detected by the camera controller 14 and the longitudinal axis of the host vehicle, the lateral displacement X from the center of the traveling lane, the traveling lane curvature β, and the obstacle detected by the radar controller 16 Whether the image of the road white line ahead of the host vehicle could be captured by the CCD camera 13, that is, whether the road white line could be detected by the camera controller 14. And a driving torque Tw controlled by the driving torque control unit 12 are also output to the braking / driving force control unit 8 together. When the detected vehicle traveling state data has left and right directions, the left direction is the positive direction. That is, the yaw rate φ ′, the lateral acceleration Yg, and the yaw angle φ are positive values when turning left, and the lateral displacement X is a positive value when deviating from the center of the traveling lane to the left. When the camera controller 14 cannot detect the road white line, “0” is output as the angle φ formed between the traveling lane and the longitudinal axis of the host vehicle, the lateral displacement X from the center of the traveling lane, and the traveling lane curvature β. The
In addition, this vehicle is provided with an in-vehicle information presentation device 23 having a display and a speaker. When the vehicle has a tendency to deviate from the lane, the vehicle is driven by sound or buzzer sound according to a command from the braking / driving force control unit 8. A warning to the person.

  Next, the logic of the arithmetic processing performed in the braking / driving force control unit 8 will be described with reference to the flowchart of FIG. This calculation process is executed by a timer interrupt every predetermined sampling time ΔT every 20 msec., For example. In this flowchart, no communication step is provided, but information obtained by the arithmetic processing is updated and stored in the storage device as needed, and necessary information is read out from the storage device as needed.

  In this calculation process, first, in step S1, various data are read from each sensor, controller, and control unit. Specifically, the longitudinal acceleration Xg, lateral acceleration Yg, yaw rate φ ′ detected by each sensor, each wheel speed Vwi, steering angle δ, accelerator opening Acc, master cylinder pressure Pm, direction indicating switch signal, and driving The driving torque Tw from the torque control unit 12, the angle φ between the traveling lane and the longitudinal axis of the host vehicle, the lateral displacement X from the center of the traveling lane, the traveling lane curvature β, and the recognition determination signal are read from the camera controller 14. Further, it is determined whether or not the recognition determination signal read from the camera controller 14 indicates that the road white line has been detected. If the signal indicates that the road white line has been detected, the recognition flag Fcamready is determined. Is set to “1”, otherwise the recognition flag Fcamready is set to “0” reset state.

  Next, the process proceeds to step S2, and the traveling speed V of the host vehicle is calculated. Specifically, the average value of the front left and right wheel speeds VwFL and VwFR, which are non-driven wheels, is calculated from the wheel speeds Vwi read in step S1, and the calculation result is used as the traveling speed V of the host vehicle. When the anti-skid control is being performed, the estimated vehicle speed calculated by the anti-skid control is set as the traveling speed V of the host vehicle.

Next, the process proceeds to step S3, where a future estimated lateral displacement XS is calculated. Specifically, the angle φ formed between the travel lane of the host vehicle read in step S1 and the longitudinal axis of the host vehicle, the lateral displacement X from the center of the travel lane, the travel lane curvature β, and the calculation in step S2. Based on the travel speed V of the subject vehicle, a future estimated lateral displacement XS is calculated according to the following equation (1).
XS = Tt × V × (φ + Tt × V × β) + X (1)
However, Tt is the vehicle head time for calculating the forward gaze distance, and becomes the front gaze distance when the vehicle head time Tt is multiplied by the traveling speed V of the host vehicle. That is, the estimated lateral displacement from the center of the traveling lane after the vehicle head time Tt becomes the estimated lateral displacement XS in the future.

Next, the process proceeds to step S4, where it is detected that the front wheels 5FL, 5FR are traveling on the road surface unevenness provided on the road white line. Since such road surface irregularities are usually formed by repeating concave and convex portions at regular intervals, as shown in FIG. 3, the wheel speeds VwFL and VwFR have a substantially constant cycle as shown in FIG. fluctuate. Therefore, here, when the wheel speeds VwFL and VwFR are fluctuating at a constant cycle, it is detected that the front wheels 5FL and 5FR are traveling on the road surface unevenness provided on the road white line. Although only the front left wheel 5FL will be described here, the same processing is performed for the front right wheel 5FR. Specifically, first, the wheel acceleration dVwFL is calculated according to the following equation (2) based on whether or not the wheel speed VwFL of the front left wheel 5FL fluctuates, that is, based on the front left wheel speed VwFL read in step S1. It is determined whether or not the acceleration dVwFL has become larger than the determination threshold value Slimit. When the wheel acceleration dVwFL becomes larger than the judgment threshold value Slimit, whether or not a predetermined time has elapsed since the wheel speed VwFL of the front left wheel 5FL has fluctuated last time, that is, whether or not the counter TsFL is equal to or less than the predetermined value TsL. If the counter TsFL is equal to or smaller than the predetermined value TsL, the counter TsFL is set to the initial set value Tso, and the road surface determination start flag FrsFL is set to “1”. Here, the judgment threshold Slimt and the initial set value Tso are calculated according to the control map of FIG. 4 and the control map of FIG. 5 based on the traveling speed V of the host vehicle calculated in step S2.
dVwFL = Kg × (VwFL20−VwFL) / ΔT (2)
However, VwFL20 is the wheel speed VwFL detected when this calculation process was executed last time, and Kg is a unit conversion coefficient.

  Note that the fluctuation cycle and fluctuation width of the wheel acceleration dVwFL, that is, the fluctuation period and fluctuation width of the wheel speed VwFL change according to the traveling speed V of the host vehicle. For example, when the traveling speed V of the host vehicle is small, fluctuations as shown in FIG. 3 appear for each unevenness. However, when the traveling speed V of the host vehicle is large, the fluctuations shown in FIG. It does not appear. That is, when the traveling speed V of the host vehicle is high, the influence of the tire characteristics and suspension characteristics increases, the fluctuation cycle of the wheel speeds VwFL and VwFR increases, and the fluctuation range of the wheel speeds VwFL and VwFR decreases. Therefore, as shown in FIG. 4, the determination threshold Slimt is a relatively large constant value in a region where the traveling speed V of the host vehicle is relatively low, and is relatively small in a region where the traveling speed V of the host vehicle is relatively large. It is set to a constant value, and is set so as to decrease linearly as the traveling speed V of the host vehicle increases between these areas. Further, as shown in FIG. 5, the initial set value Tso is also a relatively large constant value in a region where the traveling speed V of the host vehicle is relatively low, and a relatively small constant in a region where the traveling speed V of the host vehicle is relatively large. The values are set so as to decrease linearly as the traveling speed V of the host vehicle increases.

When the counter TsFL is larger than the predetermined value TsL, the predetermined value is subtracted from the counter TsFL and the predetermined value is added to the unevenness determination timer TrsFL. When the counter TsFL is “0” or less, the road surface determination start flag FrsFL is reset to “0”, and the unevenness determination timer TrsFL is set to “0”.
On the other hand, when the wheel acceleration dVwFL is equal to or less than the determination threshold value Slimit, or when the wheel acceleration dVwFL calculated when the calculation process was executed last time is larger than the determination threshold value Slimit, the predetermined value is obtained from the counter TsFL. The value is subtracted, and a predetermined value is added to the unevenness determination timer TrsFL. When the counter TsFL is “0” or less, the road surface determination start flag FrsFL is reset to “0”, and the unevenness determination timer TrsFL is set to “0”.

  With this configuration, as shown in section C of FIG. 6, when the wheel acceleration dVwFL becomes larger than the determination threshold value Slimit, the counter TsFL is set to the initial set value Tso and the counter TsFL is gradually decreased. In addition, the unevenness determination timer TrsFL is gradually increased. When the wheel acceleration dVwFL again becomes larger than the judgment threshold value Slimit from when the counter TsFL becomes equal to or less than "0" after the counter TsFL becomes equal to or less than the predetermined value TSL, that is, the wheel speed VwFL becomes substantially constant (Tso-TsL). ), The counter TsFL is set to the initial set value Tso again, and the unevenness determination timer TrsFL continues to increase. Incidentally, when the wheel speed VwFL does not fluctuate at a constant cycle (Tso−TsL), for example, when the wheel speed VwFL, VwFR fluctuates temporarily greatly by stepping on something falling on the road surface, FIG. As shown in sections A and B, the counter TsFL is temporarily set to the initial set value Tso, but the counter TsFL is gradually reduced to “0”, and the unevenness determination timer TrsFL immediately becomes “0”. turn into.

Next, it is determined whether the unevenness determination timer TrsFL is larger than the determination threshold value Trslmt. If the unevenness determination timer Trslmt is larger than the determination threshold value Trslmt, the unevenness determination flag FotFL is set to “1”, that is, the front left wheel 5FL is on the road. A state indicating that the vehicle is traveling on the road surface unevenness provided on the white line is set, and if not, the unevenness determination flag FotFL is set to a reset state of “0”.
As described above, in this embodiment, when the wheel speed VwFL of the host vehicle fluctuates at a substantially constant cycle (Tso−TsL) corresponding to the traveling speed V of the host vehicle, the unevenness determination flag FotFL is set to “1”. Therefore, only when the front left wheel 5FL is on the road surface unevenness that repeats the concave and convex portions at regular intervals, it is detected that the host vehicle is traveling on the road surface unevenness provided on the white road line. The Incidentally, in the method of simply setting the unevenness determination flag FotFL to “1” when the vehicle wheel speed VwFL fluctuates, the unevenness determination flag FotFL is set to “1” even when a simple protrusion or the like is stepped on. May be erroneously detected that the vehicle is traveling on the road surface unevenness provided on the road white line.

  Next, the process proceeds to step S5, and it is detected that the host vehicle is traveling on the left end or the right end of the travel lane. Specifically, it is determined whether only one of the unevenness determination flag FotFL corresponding to the front left wheel 5FL and the unevenness determination flag FotFR corresponding to the front right wheel 5FR is in the set state of “1”. When only one of the unevenness determination flag FotFL corresponding to the left wheel 5FL and the unevenness determination flag FotFR corresponding to the front right wheel 5FR is set to “1”, the unevenness determination flag FotFL corresponding to the front left wheel 5FL is set. Is set to "1". When the unevenness determination flag FotFL corresponding to the front left wheel 5FL is set to “1”, the road edge determination flag Fdw is set to “1”, that is, the host vehicle is traveling on the left end of the driving lane. Otherwise, the road edge determination flag Fdw is set to “−1”, that is, the vehicle is traveling on the right edge of the traveling lane.

Further, when both the unevenness determination flag FotFL corresponding to the front left wheel 5FL and the unevenness determination flag FotFR corresponding to the front right wheel 5FR are in the set state of “1” or the reset state of “0”, the road edge determination flag Fdw is set to a reset state of “0”.
As described above, in the present embodiment, when only one of the unevenness determination flag FotFL corresponding to the front left wheel 5FL and the unevenness determination flag FotFR corresponding to the front right wheel 5FR is set to “1”, the road edge In order to set the determination flag Fdw to “1” or “−1”, the road surface unevenness provided on the road white line only when only one of the front left and right wheels 5FL, 5FR is stepping on the road surface unevenness. It is detected that the vehicle is traveling over the vehicle. In addition, although the example using the unevenness | corrugation judgment flags FotFL and FotFR which will be in the set state of "1" when the wheel speeds VwFL and VwFR fluctuate with a fixed period was shown, it is not restricted to this, For example, just a wheel A flag that is set when the speeds VwFL and VwFR change may be used.

Incidentally, in the method of detecting that the host vehicle is traveling on the road surface unevenness provided on the road white line of the traveling lane of the host vehicle when the wheel speed VwFL of the host vehicle fluctuates, Even when the entire road is uneven, such as when traveling, there is a risk of erroneous detection that the host vehicle is traveling on the road surface unevenness provided on the road white line.
Next, it transfers to step S6 and it is determined whether the driver | operator has changed the lane intentionally. Specifically, the traveling direction (left-right direction) of the host vehicle determined from the direction indicating switch 22 read in step S1 and the sign of the estimated lateral displacement XS calculated in step S3 (positive in the left direction). When the traveling direction of the host vehicle determined from the above is coincident, the lane change determination flag FLC is set to “1”, that is, a state indicating that the driver has intentionally changed the lane. When the two do not coincide, the lane change determination flag FLC is set to a reset state of “0”, that is, a state indicating that the driver has not intentionally changed the lane.

  It should be noted that once the lane change determination flag FLC is set by operating the direction indicating switch 22, even if the operation of the direction indicating switch 22 is released, the set state is maintained for a certain time (for example, 4 seconds). . Thereby, even if the operation of the direction instruction switch 22 is canceled during the lane change by the driving operation, it is possible to prevent the departure avoidance control from being started during the lane change. Even if the direction indicating switch 22 is not operated, the traveling direction of the host vehicle determined from the sign of the estimated lateral displacement XS calculated in step S3 and the sign of the steering angle δ read in step 1 are described. When the steering angle δ and the time change rate Δδ thereof are equal to or greater than a predetermined value, the lane change determination flag FLC is set to “1”, that is, the driver intentionally Is a state indicating that the lane has been changed.

Next, it transfers to step S7 and it is determined whether it warns that the own vehicle is deviating from a driving lane. Specifically, the alarm determination threshold value Xw is calculated according to the following equation (3), the lane change determination flag FLC set in step S6 is in the reset state, and is calculated in step S3. It is assumed that an alarm is issued when the absolute value | XS | of the estimated future lateral displacement thus made is greater than the alarm judgment threshold value Xw, and no alarm is issued otherwise. When the alarm is activated, the alarm is continued until the absolute value | XS | of the estimated lateral displacement in the future becomes equal to or less than (Xw−Xh). Here, Xh is a hysteresis for avoiding alarm hunting. In this embodiment, the alarm is activated based only on the absolute value | XS | of the estimated lateral displacement in the future, and the virtual deviation estimated value XSv is not considered for simplicity.
Xw = Xc-Xm (3)

However, Xm is a constant and is the margin from when the alarm is activated until when the departure prevention control is activated. Further, the lateral displacement limit value Xc is a constant. For example, in Japan, the lane width of the highway is “3.35” m. In the present embodiment, an example in which the lateral displacement limit value Xc is a fixed value has been described. However, the present invention is not limited to this. For example, image processing is performed on a captured image in front of the host vehicle captured by the CCD camera 13. Or by taking in lane width information corresponding to the position of the host vehicle from a so-called car navigation system or infrastructure, and calculating the lane width L of the traveling lane, and based on the lane width L, according to the following equation (4) The lateral displacement limit value Xc may be calculated as needed. Further, when information on the distance (L / 2−XS) from the infrastructure such as a marker embedded in the road to the lane in the departure direction of the host vehicle can be taken in, the information may be used.
Xc = min (L / 2-LC / 2, 0.8) (4)
However, LC is a vehicle width of the own vehicle, and min () is a function for selecting a minimum value from a plurality of values.

  Next, the process proceeds to step S8, in which it is determined whether or not the host vehicle tends to deviate from the traveling lane. Specifically, it is determined whether or not the future estimated lateral displacement XS calculated in step S3 is greater than or equal to the lateral displacement limit value Xc, and the future estimated lateral displacement XS is greater than or equal to the lateral displacement limit value Xc. The departure determination flag FLD is set to “1”, that is, a state indicating that the own vehicle has a tendency to deviate leftward from the driving lane.

  Further, when the estimated future lateral displacement XS is smaller than the lateral displacement limit value Xc, it is determined whether or not the future estimated lateral displacement XS is larger than a value obtained by inverting the sign of the lateral displacement limit value Xc (-Xc). If the estimated lateral displacement XS in the future is larger than the value obtained by inverting the sign of the lateral displacement limit value Xc (−Xc), the departure determination flag FLD is reset to “0”, that is, the host vehicle is moved from the traveling lane. It is assumed that there is no deviation tendency.

  When the estimated lateral displacement XS in the future is equal to or less than the value (-Xc) obtained by inverting the sign of the lateral displacement limit value Xc, the departure determination flag FLD is set to "-1", that is, the host vehicle. Is a state indicating that there is a tendency to deviate from the traveling lane to the right. Note that when the lane change determination flag FLC set in step S6 is in the set state, that is, when the driver intentionally changes the lane, the lane departure avoidance control is not performed, and therefore the future estimated lateral displacement Even if the absolute value | XS | is equal to or greater than the lateral displacement limit value Xc, the departure determination flag FLD is reset to "0". Similarly, lane departure avoidance control is not performed when anti-skid control, traction control, vehicle dynamics control, etc. are performed, that is, when the tire is within the limit range. Even if the absolute value | XS | of the displacement is equal to or greater than the lateral displacement limit value Xc, the departure determination flag FLD is reset to "0".

As described above, in the present embodiment, when the absolute value | XS | of the estimated lateral displacement in the future is equal to or greater than the lateral displacement limit value Xc, the departure determination flag FLD is set to “1” or “−1”. Since it is determined that the host vehicle has a tendency to deviate from the travel lane, the tendency to deviate from the travel lane can be detected appropriately.
Next, the process proceeds to step S9, where it is determined whether the camera controller 14 has detected a road white line, that is, whether the recognition flag Fcamready set in step S1 is set to "1". If it is in a state (Yes), the process proceeds to step S10. If not (No), the process proceeds to step S13.

In step S10, it is determined whether the host vehicle is traveling on the left end or the right end of the travel lane. Specifically, it is determined whether or not the road edge determination flag Fdw set in step S5 is set to “1” or “−1”. If it is set (Yes), step The process proceeds to S12, and if not (No), the process proceeds to Step 11.
In step S11, the control gain Khr is set to the normal value “1”, the control amount offset Moffset is set to “0”, and then the process proceeds to step S16.

On the other hand, in step S12, the control gain Khr is set to a predetermined value Khr1 (> 1), the control amount offset Moffset is set to “0”, and then the process proceeds to step S16.
On the other hand, in the step S13, it is determined whether or not the host vehicle is traveling on the left end or the right end of the travel lane. Specifically, it is determined whether or not the road edge determination flag Fdw set in step S5 is set to “1” or “−1”. If it is set (Yes), the process goes to step S15. If not (No), go to Step 14.

In step S14, the control gain Khr is set to “0”, the control amount offset Moffset is also set to “0”, and then the process proceeds to step S16.
On the other hand, in step S15, the control gain Khr is set to “0”, the control amount offset Moffset is set to a constant value Mo, and then the process proceeds to step S16. The constant value Mo is set so that the fluctuation of the vehicle behavior due to the target yaw rate Ms calculated in step S16 described later becomes moderate.

  As described above, in this embodiment, when the recognition flag Fcamready is in the reset state of “0” and the road edge determination flag Fdw is in the set state of “1” or “−1”, that is, the road white line ahead of the host vehicle. Although it is not detected from the image that the host vehicle tends to deviate from the driving lane, it is detected that the front wheels 5FL, 5FR are traveling on the road surface unevenness provided on the road white line. Since the control amount offset Moffset is set to a constant value Mo, the fluctuation of the vehicle behavior can be made natural for the driver.

Next, the process proceeds to step S16, and the target yaw moment Ms is calculated. Specifically, whether or not the departure determination flag FLD set in step S8 is “1” or the road edge determination flag Fdw calculated in step S5 is “1” or “−1”. When the departure determination flag FLD is “1” or the road edge determination flag Fdw is “1” or “−1”, that is, when the own vehicle has a tendency to deviate from the driving lane, When the vehicle is traveling on the left end or the right end of the travel lane, the target yaw moment Ms is calculated according to the following equation (5). Otherwise, the target yaw moment Ms is set to “0”.
Ms = −Khr × K1 × K2 × (XS−Xc) −Fdw × Moffset (5)

  However, K1 is a proportional coefficient determined from vehicle specifications, K2 is a proportional coefficient calculated according to the control map of FIG. 7 based on the traveling speed V of the host vehicle, and Khr is set in steps S10 to S15. Control gain. As shown in FIG. 7, the proportional coefficient K2 has a relatively large constant value in a region where the traveling speed V of the host vehicle is relatively low, and a relatively small constant value in a region where the traveling speed V of the host vehicle is relatively large. Thus, the area is set so as to decrease linearly as the traveling speed V of the host vehicle increases.

  As described above, in the present embodiment, when the departure determination flag FLD is in the set state, the target yaw moment Ms is calculated so as to avoid the departure from the traveling lane of the own vehicle. When the departure tendency occurs, the yaw moment is generated at an early timing in a direction to avoid the departure of the own vehicle from the traveling lane, and the departure of the own vehicle from the traveling lane is more reliably avoided. At this time, since the target yaw moment Ms is calculated from the difference between the estimated lateral displacement XS and the first lateral displacement limit value Xc in the future, a yaw moment corresponding to the magnitude of the difference is generated, and the vehicle travels. Deviations from the lane are more reliably avoided.

  Next, the process proceeds to step S17, and the target braking fluid pressure Psi for each wheel is calculated. Specifically, when the master cylinder pressure Pm read based on the front / rear braking force distribution is set to PmR with respect to the master cylinder pressure Pm read in step S1, the departure determination flag FLD set in step S3 is “ When the road edge determination flag Fdw set in step S5 is "0" in the reset state in which the vehicle is in a reset state of "0", that is, the host vehicle has no tendency to deviate from the driving lane and the host vehicle is in the driving lane When the vehicle is not traveling at the left end or right end of the vehicle, the target brake fluid pressure PSFL, PSFR to the wheel cylinders 6FL, 6FR of the front left and right wheels 5FL, 5FR is set to the master cylinder pressure Pm, and the wheel cylinder 6RL of the rear left and right wheels 5RL, 5RR is used. , The target brake fluid pressure PSRL and PSRR to 6RR are both set as the rear wheel master cylinder pressure PmR.

Further, when at least one of the departure determination flag FLD and the road end determination flag Fdw is in a set state, that is, when the own vehicle has a tendency to deviate from the traveling lane, the own vehicle travels on the left end or the right end of the traveling lane. If the target yaw moment Ms calculated in step S17 is determined, the case is divided. That is, when the absolute value | Ms | of the target yaw moment is less than the predetermined value Ms1, a difference is generated only in the braking force of the rear left and right wheels 5RL and 5RR, and the absolute value | Ms | of the target yaw moment is the predetermined value Ms1. When this is the case, a difference is generated in the braking force of each of the wheels 5FL to 5RR. That is, when the absolute value | Ms | of the target yaw moment is less than the predetermined value Ms1, the front left and right wheel target braking fluid pressure difference ΔPSF is “0”, and the rear left and right wheel target braking fluid pressure difference ΔPSR is expressed by the following equation (6). Is calculated according to Similarly, the front left and right wheel target braking fluid pressure difference ΔPSF when the absolute value | Ms | of the target yaw moment is equal to or greater than the predetermined value Ms1 is calculated according to the following equation (7). Calculated according to equation (8). In the equation, T is a tread (same for front and rear wheels), KbF and KbR are conversion coefficients for converting braking force into braking fluid pressure, and are determined by brake specifications.
ΔPSR = 2 × KbR × | Ms | / T (6)
ΔPSF = 2 × KbF × (| Ms | −Ms1) / T (7)
ΔPSR = 2 × KbR × Ms1 / T (8)

Therefore, when the target yaw moment Ms is a negative value, that is, when the host vehicle is about to deviate to the left, the target braking fluid pressure Psi to each wheel cylinder 6FL-6RR is calculated according to the following equation (9). Is done.
PSFL = Pm
PSFR = Pm + ΔPSF
PSRL = PmR
PSRR = PmR + ΔPSR (9)

On the other hand, when the target yaw moment Ms is a positive value, that is, when the host vehicle is about to deviate in the right direction, the target braking fluid pressure Psi to each of the wheel cylinders 6FL to 6RR is expressed by the following equation (10). Calculated.
PSFL = Pm + ΔPSF
PSFR = Pm
PSRL = PmR + ΔPSR
PSRR = PmR (10)
Thus, in this embodiment, since the target braking fluid pressures PSFL to PSRR of each wheel are calculated so that the target yaw moment Ms is generated, lane departure avoidance control can be performed regardless of the driver's steering operation. In addition, lane departure avoidance control can be performed with appropriate target braking fluid pressures PSFL to PSRR.

  Next, the process proceeds to step S18, and the target drive torque TrqDS of the drive wheels 5RL and 5RR is calculated. Specifically, when the departure determination flag FLD is “1” or “−1” or the road edge determination flag Fdw is “1” or “−1”, that is, when lane departure avoidance control is performed, the accelerator Even if the operation is being performed, the engine output is reduced to prevent acceleration. That is, the target drive torque TrqDS when the lane departure avoidance control is performed is based on the sum of the target braking fluid pressure differences ΔPSF and ΔPSR of the front and rear wheels from the value corresponding to the accelerator opening Acc read in step S1. Value obtained by subtracting Here, the value according to the accelerator opening Acc is a driving torque for accelerating the host vehicle according to the accelerator opening Acc, and the value according to the sum of the target braking fluid pressure differences ΔPSF and ΔPSR of the front and rear wheels. , A braking torque generated by the sum of the target braking fluid pressure differences ΔPSF and ΔPSR. Therefore, when the lane departure avoidance control is performed, the engine torque is reduced by the amount of braking torque generated by the sum of the target braking fluid pressure differences ΔPSF and ΔPSR. Note that when the departure determination flag FLD is “0” and the departure avoidance control restriction flag Fcancel is in a set state, that is, when lane departure avoidance control is not performed, the target drive torque TrqDS is equal to the accelerator opening Acc. Accordingly, only the driving torque for accelerating the host vehicle is obtained. Further, although an example in which priority is given to the lane departure avoidance control over the driver's accelerator operation is shown, the present invention is not limited to this, for example, the driver's accelerator operation has priority over the lane departure avoidance control, and the accelerator opening degree The absolute value of the target yaw moment Ms may be decreased as Acc increases.

  Next, the process proceeds to step S19, and the target brake fluid pressures PsFL to PsRR of the wheels 5FL to 5RR calculated in step S17 are output to the brake fluid pressure control circuit 7 and calculated in step S18. After the target drive torque TrqDS of the drive wheels 5RL and 5RR is output to the drive torque control unit 12, the program returns to the main program.

Next, the operation of the lane departure prevention apparatus of the present invention will be described based on a specific situation.
First, when the CCD camera 13 can capture an image of the road white line ahead of the host vehicle, a large departure tendency from the traveling lane of the host vehicle to the left occurs due to the driver's side look etc., as shown in FIG. In addition, it is assumed that the front left wheel 5FL is on the road surface unevenness provided on the road white line on the left side of the traveling lane of the host vehicle. Then, in the calculation process of the braking / driving force control unit 8, first, in step S1, various data are read from the respective sensors, controllers, and control units, and fluctuate at a constant cycle as shown in a section D in FIG. The wheel speed VwFL of the front left wheel 5FL is read, the recognition flag Fcamready is set to “1”, the traveling speed V of the host vehicle is calculated in step S2, and based on the traveling speed V and the like in step S3. The estimated future lateral displacement XS is calculated to be larger than the lateral displacement limit value Xc. In step S4, only the unevenness determination flag FotFL corresponding to the front left wheel 5FL is set to "1" based on the wheel speed VwFL. In S5, the road edge determination flag Fdw is set to "1" based on the unevenness determination flag FotFL. In step S6, the lane change determination flag is set. The flag FLC is reset to "0". After step S7, in step S8, the departure determination flag FLD is set to "1" based on the estimated future lateral displacement XS, and the recognition flag Fcamready Based on the road edge determination flag Fdw, the determinations in steps S9 and S10 are “Yes”, the control gain Khr is set to a predetermined value Khr1 (> 1) in step S12, and the control gain Khr is set in step S16. The target yaw moment Ms is set so that a large yaw moment is generated in a direction (right direction) that avoids lane departure of the host vehicle by multiplying by the value obtained by subtracting the lateral displacement limit value Xc from the future estimated lateral displacement XS. In step S17, the target braking fluid pressures PsFR and PsRR to the right wheels 5FR and 5RR are largely calculated based on the target yaw moment Ms, and the process goes through step S18. In step S19, the target braking fluid pressure PsFL~PsRR is output to the brake hydraulic pressure control circuit 7. When the target brake fluid pressures PsFL to PsRR are acquired by the brake fluid pressure control circuit 7, the target brake fluid pressures PsFR and PsRR are output to the right wheels 5FR and 5RR, and a large yaw moment is generated in the right direction. As a result, deviation of the host vehicle from the driving lane is avoided.

  As described above, in this embodiment, it is detected that the host vehicle has a tendency to deviate from the driving lane to the left, and the front left wheel 5FL is detected on the road surface unevenness provided on the road white line. When this is done, the target yaw moment Ms is largely calculated and a large yaw moment is generated in the direction (right direction) that avoids the departure of the host vehicle from the lane, so that the departure of the host vehicle from the traveling lane can be avoided more reliably. By the way, when it is detected from the image of the road white line ahead of the host vehicle that the host vehicle tends to deviate from the driving lane, the yaw moment is simply generated in a direction to avoid the lane departure of the host vehicle. The target yaw moment Ms is calculated to be small due to an error when detecting the departure tendency from the image, and the lane departure avoidance performance from the traveling lane of the host vehicle may be deteriorated.

  Further, when the prospect is poor due to fog, rain, etc. and the CCD camera 13 cannot capture an image of the road white line ahead of the host vehicle, the vehicle tends to deviate from the traveling lane to the left, as shown in FIG. Thus, it is assumed that the front left wheel 5FL is on the road surface unevenness provided on the road white line on the left side of the traveling lane of the host vehicle. Then, in the calculation process of the braking / driving force control unit 8, first, in step S1, as shown in the section D of FIG. 9, the wheel speed VwFL of the front left wheel 5FL, which fluctuates at a constant cycle, is read and “0” is read as the angle φ formed with the longitudinal axis of the vehicle, the lateral displacement X from the center of the travel lane, and the travel lane curvature β, the recognition flag Fcamready is reset to “0”, and after step S2, In step S3, a future estimated lateral displacement XS is set to "0" based on an angle φ formed between the travel lane and the longitudinal axis of the host vehicle. In step S4, the front left wheel 5FL is determined based on the wheel speed VwFL. Only the unevenness determination flag FotFL corresponding to is set to "1". In step S5, the road edge determination flag Fdw is set to "1" based on the unevenness determination flag FotFL. In step S6, the lane change determination flag FotFL is set. The flag FLC is set to “0”, and after step S7, in step S8, the departure determination flag FLD is set to “0” based on the estimated future lateral displacement XS, and the determination in step S9 is performed based on the recognition flag Fcamready. Becomes “No”, the determination in step S13 becomes “Yes” based on the road edge determination flag Fdw, the control amount offset Moffset is set to a constant value Mo in step S15, and the control amount offset in step S16. Based on Moffset, the target yaw moment Ms is calculated so that a constant yaw moment is generated in the direction (right direction) to return to the center position of the traveling lane of the host vehicle, and in step S17, based on the target yaw moment Ms. The target braking fluid pressures PsFR and PsRR for the right wheels 5FR and 5RR are greatly calculated. After step S18, in step S19, the target braking fluid pressures PsFR and PsRR are calculated. Fluid pressure PsFL~PsRR is output to the brake hydraulic pressure control circuit 7. When the target brake fluid pressures PsFL to PsRR are acquired by the brake fluid pressure control circuit 7, the target brake fluid pressures PsFR and PsRR are output to the right wheels 5FR and 5RR, and a constant yaw moment is generated in the right direction. As a result, the host vehicle returns to the center position of the traveling lane, and deviation of the host vehicle from the traveling lane is avoided.

  As described above, in the present embodiment, when it is detected that the front left wheel 5FL is on the road surface unevenness provided on the road white line, a constant target yaw moment Ms is calculated and the vehicle travels. Since a constant yaw moment is generated in the direction toward the center of the lane (to the right), even when the CCD camera 13 cannot capture the image of the road white line ahead of the host vehicle, the vehicle deviates from the driving lane. Can be avoided. In addition, by generating a constant yaw moment in the right direction, the vehicle can be turned faster than the driver notices that the front left wheel 5FL is on the road surface unevenness, and the driver can change the steering direction. By informing the driver, the driver can have a mental margin and a time margin.

  Next, a second embodiment of the lane departure prevention apparatus of the present invention will be described. In this embodiment, the front wheels 5FL and 5FR are traveling on the road surface unevenness of the traveling lane of the host vehicle without detecting that the host vehicle tends to deviate from the traveling lane from the image of the road white line ahead of the host vehicle. The point which performs vehicle control only at the time differs from the said 1st Embodiment. Specifically, steps S3, S7 and S9 to S15 of the calculation process of FIG. 2 performed by the braking / driving force control unit 8 of the first embodiment are deleted, and steps S8 and S16 are the calculation process of FIG. Steps S8 ′ and S16 ′ are changed. The arithmetic processing in FIG. 10 includes many steps equivalent to the arithmetic processing in FIG. 2 of the first embodiment, and the same steps are denoted by the same reference numerals and detailed description thereof is omitted.

  In step S8 ′, it is determined whether or not the host vehicle tends to deviate from the traveling lane. Specifically, it is determined whether or not the lane change determination flag FLC set in step S6 is a reset state of “0”. If the lane change determination flag FLC is in a reset state of “0”, it is determined whether the road edge determination flag Fdw set in step S5 is in a set state of “1”, and the road edge When the determination flag Fdw is set to “1”, the departure determination flag FLD is set to “1”, that is, a state indicating that the host vehicle tends to deviate leftward from the driving lane.

  When the road edge determination flag Fdw is not set to “1”, it is determined whether or not the road edge determination flag Fdw is set to “−1”, and the road edge determination flag Fdw is “−”. If the vehicle is in the 1 "set state, the departure determination flag FLD is set to the" -1 "set state, that is, a state indicating that the host vehicle tends to deviate from the traveling lane to the right. When the road edge determination flag Fdw is in a reset state of “0”, the departure determination flag FLD is set in a reset state of “0”.

  On the other hand, when the lane change determination flag FLC is set to “1”, that is, when the driver intentionally changes the lane, the lane departure avoidance control is not performed, so the departure determination flag FLD is set to “ 0 ". Similarly, the lane departure avoidance control is not performed when anti-skid control, traction control, vehicle dynamics control or the like is performed, that is, when the tire is in the limit range. 0 ".

Next, the process proceeds to step S16 ′ to calculate the target yaw moment Ms. Specifically, it is determined whether or not the departure determination flag FLD set in step S8 ′ is “1” or “−1”, and the departure determination flag FLD is “1” or “−1”. In some cases, that is, when the host vehicle is traveling on the left end or the right end of the travel lane, the target yaw moment Ms is calculated according to the following equation (11). Otherwise, the target yaw moment Ms is set to “0”.
Ms = −Fdw × Mo (11)
Instead of the constant value Mo, a value determined according to the turning state, such as a vehicle speed, a yaw rate, or a lateral acceleration, may be used.

Next, the operation of the lane departure prevention apparatus of the present invention will be described based on a specific situation.
First, when the prospect is not good due to fog, rain, etc., the vehicle tends to deviate to the left from the driving lane of the vehicle, and as shown in FIG. 8, it is provided on the road white line on the left side of the driving lane of the vehicle. Suppose that there is a front left wheel 5FL on the uneven road surface. Then, in the calculation process of the braking / driving force control unit 8, first, in step S1, various data are read from the respective sensors, controllers, and control units, and fluctuate at a constant cycle as shown in a section D in FIG. The wheel speed VwFL of the front left wheel 5FL is read, and after step S2, only the unevenness determination flag FotFL corresponding to the front left wheel 5FL is set to "1" based on the wheel speed VwFL in step S4, and step S5 The road edge determination flag Fdw is set to “1” based on the unevenness determination flag FotFL, the lane change determination flag FLC is set to “0” in step S6, and the lane change determination flag FLC is set in step S8 ′. The departure determination flag FLD is set to “1” based on the road edge determination flag Fdw, and the departure determination flag is set in step S16 ′. Based on the LD, the target yaw moment Ms is calculated so that a constant yaw moment is generated in the direction (right direction) to return to the center position of the traveling lane of the host vehicle. In step S17, the target yaw moment Ms is calculated. The target braking fluid pressures PsFR and PsRR for the right wheels 5FR and 5RR are greatly calculated, and after step S18, the target braking fluid pressures PsFL to PsRR are output to the braking fluid pressure control circuit 7 in step S19. When the target brake fluid pressures PsFL to PsRR are acquired by the brake fluid pressure control circuit 7, the target brake fluid pressures PsFR and PsRR are output to the right wheels 5FR and 5RR, and a constant yaw moment is generated in the right direction. As a result, the host vehicle returns to the center position of the traveling lane, and deviation of the host vehicle from the traveling lane is avoided.

As described above, in the present embodiment, the detection of the wheel speed sensor for anti-skid control is performed in order to detect the presence of the front left wheel 5FL on the road surface unevenness based on the wheel speed VwFL of the host vehicle. By using the result, the lane departure prevention device can be configured at low cost without providing a dedicated sensor or the like.
Next, a third embodiment of the lane departure prevention apparatus of the present invention will be described. In this embodiment, when it is detected that the front wheels 5FL and 5FR are traveling on the road surface unevenness provided on the road white line, a steering torque that causes the host vehicle to move toward the center position of the traveling lane is generated. This is different from the second embodiment.

FIG. 11 is a schematic configuration diagram of a third embodiment of the lane departure prevention apparatus of the present invention.
The front wheels 5FL and 5FR in the drawing are provided with a general rack and pinion type steering mechanism. The steering mechanism includes a rack 24 connected to the steering shafts of the front wheels 5FL and 5FR, a pinion 25 meshing with the rack 24, and a steering shaft 27 that rotates the pinion 25 with a steering torque applied to the steering wheel 26. Yes.

  Further, an automatic steering mechanism 28 that constitutes a steering actuator for automatically steering the front wheels 5FL and 5FR is disposed above the pinion 25 in the steering shaft 27. The automatic steering mechanism 28 includes a driven gear 29 that is coaxially attached to the steering shaft 27, a drive gear 30 that meshes with the driven gear 29, and an automatic steering motor 31 that rotationally drives the drive gear 30. A clutch mechanism 32 is interposed between the automatic steering motor 31 and the drive gear 30. The clutch mechanism 32 is engaged only during automatic steering control, and otherwise the clutch mechanism 32 is not engaged. Thus, the rotational force of the automatic steering motor 31 is prevented from being input to the steering shaft 27.

  Further, in the present embodiment, steps S17 and S18 of the calculation process of FIG. 10 performed by the braking / driving force control unit 8 of the second embodiment are deleted, and steps S16 ′ and S19 are replaced by step S16 ″ of FIG. , S19 ". The arithmetic processing in FIG. 12 includes many steps equivalent to the arithmetic processing in FIG. 10 of the second embodiment, and the same steps are denoted by the same reference numerals and detailed description thereof is omitted.

In step S16 ", the target additional steering torque Tsstr is calculated. Specifically, whether or not the own vehicle has a tendency to deviate from the traveling lane, that is, the deviation determination flag FLD is" 1 "or" -1 ". If the departure determination flag FLD is “1” or “−1”, the target additional steering torque Tsstr is calculated according to the following equation (12). If not, the target additional steering is calculated. The torque Tsstr is set to “0”.
Tsstr = −FLD × Tsstr0 ……… (12)
However, Tsstr0 is a constant value.
Next, the process proceeds to step S19 ", the target additional steering torque Tsstr calculated in step S16" is output to the automatic steering motor 31, and then the process returns to the main program.

Next, the operation of the lane departure prevention apparatus of the present invention will be described based on a specific situation.
First, when the prospect is not good due to fog, rain, etc., the vehicle tends to deviate to the left from the driving lane of the vehicle, and as shown in FIG. 8, it is provided on the road white line on the left side of the driving lane of the vehicle. Suppose that there is a front left wheel 5FL on the uneven road surface. Then, in the calculation process of the braking / driving force control unit 8, in step S 1, various data are read from the respective sensors, controllers, and control units, and as shown in the section D of FIG. The wheel speed VwFL of the left wheel 5FL is read, and after step S2, only the unevenness determination flag FotFL corresponding to the front left wheel 5FL is set to "1" based on the wheel speed VwFL in step S4, and in step S5 Based on the unevenness determination flag FotFL, the road edge determination flag Fdw is set to “1”. In step S6, the lane change determination flag FLC is set to “0”. In step S8 ′, the lane change determination flag FLC The departure determination flag FLD is set to "1" based on the road edge determination flag Fdw, and the departure determination flag FLD is set in step S16 ". Based on this, the target additional steering torque Tsstr is calculated so that the steering angle δ is generated in the direction (right direction) to return the host vehicle to the center position of the traveling lane, and in step S19 ", the target additional steering torque Tsstr is used for automatic steering. Output toward the motor 31. When the target additional steering torque Tsstr is acquired by the automatic steering motor 31, the target additional steering torque Tsstr is output to the steering shaft 27, and a steering angle δ that is directed in the right direction is generated. The vehicle heads toward the center of the traveling lane, and deviation from the traveling lane of the host vehicle is avoided.

  As described above, in this embodiment, a drive signal corresponding to the target additional steering torque Tsstr is output to the automatic steering motor 31, and the vehicle is steered in the direction (right direction) to return to the center position of the traveling lane. In order to generate the angle δ, for example, it is possible to suppress and prevent the feeling of deceleration due to the lane departure avoidance control as compared with the method of controlling the braking force of each of the wheels 5FL to 5RR so as to avoid the departure from the traveling lane.

In the above embodiment, the CCD camera 13 in FIG. 1 constitutes the imaging means described in the claims. Similarly, the camera controller 14 in FIG. 1 constitutes the lane marking detection means, and FIG. Step S8 constitutes a departure tendency detection means, step S16 in FIG. 2 constitutes a lane departure avoidance control means, steps S4 and S5 in FIG. 2 constitute road surface unevenness detection means, and the wheel speed sensors 22FL˜ 22RR constitutes a wheel speed detecting means, and each sensor and camera controller 14 in FIG. 1 constitute a running state detecting means.
Moreover, the said embodiment shows an example of the lane departure prevention apparatus of this invention, and does not limit the structure of an apparatus.

  In the above embodiment, an example is shown in which it is detected that the front wheels 5FL and 5FR pass over the road surface unevenness provided on the white road line based on the wheel speeds VwFL and VwFR of the front left and right wheels 5FL and 5FR. However, the present invention is not limited to this. For example, the front wheels 5FL and 5FR pass above the road surface unevenness based on the vertical movement state of the suspension, that is, the acceleration and stroke amount of the vertical movement of the suspension. You may detect that. By doing so, for example, by using the detection result of the acceleration sensor or the stroke sensor for active suspension provided for improving riding comfort, the lane departure prevention device can be configured at low cost.

  In addition, for example, when it is detected by a car navigation system or the like that the host vehicle is traveling on a road other than the road, the host vehicle is traveling on the road surface unevenness provided on the road white line. Detection may be limited, so that when the vehicle is traveling on a place other than the road, such as a parking lot, the vehicle travels on the road surface unevenness provided on the road white line. It is possible to prevent false detection.

Furthermore, although the example which detects that front-wheel 5FL and 5FR are passing on the road surface unevenness | corrugation provided on the road white line was shown, it is not restricted to this, For example, as shown in FIG. , It may be detected that the vehicle is traveling on road surface unevenness provided outside the travel lane.
Moreover, as shown in FIG. 3, although the example which detects that front-wheel 5FL and 5FR are passing on the road surface unevenness | corrugation formed by providing a convex part on a road white line was shown, it is restricted to this For example, as shown in FIG. 14, it may be detected that the vehicle travels on road surface unevenness formed by providing a recess on the road white line.

  Furthermore, although the example in which the road edge determination flag Fdw is set based on the wheel speeds VFL and VFR of the front wheels 5FL and 5FR has been shown, the present invention is not limited to this. For example, the wheel speeds VRL and VRR of the rear wheels 5RL and 5RR are shown. The road edge determination flag Fdw may be set based on the above. Further, when only one of the left front and rear wheels 5FL and 5RL and the right front and rear wheels 5FR and 5RR is set to “1”, the front and rear wheels are both set. The road edge determination flag Fdw may be set to “1” only in this case, and the reliability of the road edge determination flag Fdw can be improved.

1 is a schematic configuration diagram showing a first embodiment of a vehicle equipped with a lane departure prevention apparatus of the present invention. It is a flowchart which shows the arithmetic processing performed within the braking / driving force control unit of FIG. It is explanatory drawing for demonstrating the fluctuation | variation of a wheel speed. It is a control map used for the arithmetic processing of FIG. It is a control map used for the arithmetic processing of FIG. 3 is a timing chart for explaining the operation of the arithmetic processing in FIG. 2. It is a control map used for the arithmetic processing of FIG. FIG. 3 is an explanatory diagram for explaining the operation of the arithmetic processing in FIG. 2. 3 is a timing chart for explaining the operation of the arithmetic processing in FIG. 2. It is a flowchart which shows the arithmetic processing performed in 2nd Embodiment in the braking / driving force control unit of FIG. It is a schematic block diagram which shows 3rd Embodiment of the vehicle carrying the lane departure prevention apparatus of this invention. It is a flowchart which shows the arithmetic processing performed within the braking / driving force control unit of FIG. It is explanatory drawing for demonstrating the modification of this invention. It is explanatory drawing for demonstrating the modification of this invention.

Explanation of symbols

5FL to 5RR are wheels 6FL to 6RR are wheel cylinders 7 is a braking fluid pressure control circuit 8 is a braking / driving force control unit 9 is an engine 12 is a driving torque control unit 13 is a CCD camera 14 is a camera controller 15 is an acceleration sensor 16 is a yaw rate sensor Reference numeral 17 denotes a master cylinder pressure sensor 18; an accelerator opening sensor 19; a steering angle sensor 20; and direction indication switches 22FL to 22RR.

Claims (13)

A lane marking is detected from an image ahead of the host vehicle, and the lateral displacement of the host vehicle from the center of the driving lane after a predetermined time is estimated based on the detection result. The host vehicle deviates from the driving lane based on the estimated lateral displacement. In the lane departure prevention device for performing lane departure avoidance control for avoiding departure from the traveling lane of the host vehicle when it is detected that the vehicle is in a trend,
When the lane marking cannot be detected from the image, if it is detected that the host vehicle is traveling near the lane marking or on the road surface unevenness provided on the lane marking, the vehicle is moved to the center of the driving lane. There rows vehicle control to direct the position,
When a lane marking can be detected from the image, vehicle control is performed to direct the host vehicle to the center position of the traveling lane with a control amount based on a lateral displacement from the center of the traveling lane of the host vehicle after the estimated predetermined time. When it is detected that the vehicle is traveling on the road surface unevenness, the vehicle control is performed so that the host vehicle is directed toward the center position of the traveling lane than when the road surface unevenness is not detected. A lane departure prevention apparatus characterized by increasing the absolute value of the control amount . Based on the image pickup means for picking up an image ahead of the host vehicle, the lane line detection means for detecting the lane line from the image picked up by the image pickup means, and the lane line detected by the lane line detection means Lateral displacement estimation means for estimating the lateral displacement of the host vehicle from the center of the travel lane after a predetermined time, and detecting that the host vehicle tends to deviate from the travel lane based on the lateral displacement estimated by the lateral displacement estimation means Lane departure avoidance control for avoiding the departure of the own vehicle from the traveling lane when the departure tendency detecting unit detects that the own vehicle is deviating from the traveling lane. Control means, and road surface unevenness detecting means for detecting that the host vehicle is traveling on the road surface unevenness provided near or on the lane line,
The lane departure avoidance control means, when the lane marking detection means cannot detect a lane marking, the road surface unevenness detection means causes the vehicle to move over the road unevenness provided near or on the lane marking. When it is detected that the traveling, have rows vehicle control to direct the vehicle to the center of the traffic lane,
When the lane marking can be detected by the lane marking detection means, the vehicle is placed at the center position of the driving lane with a control amount based on the lateral displacement from the center of the driving lane after the predetermined time estimated by the lateral displacement estimation means. When the vehicle surface control is detected and the road surface unevenness detecting means detects that the vehicle is traveling on the road surface unevenness, it is not detected that the vehicle is traveling on the road surface unevenness. A lane departure prevention apparatus characterized in that the absolute value of the control amount of the vehicle control for directing the host vehicle toward the center position of the traveling lane is increased . Wheel speed detection means for detecting the wheel speed of the host vehicle is provided,
The road surface unevenness detecting means detects that the host vehicle is traveling on the road surface unevenness provided near or on the lane marking based on the wheel speed detected by the wheel speed detecting means. The lane departure prevention apparatus according to claim 2, wherein:   The road surface unevenness detecting means is configured such that when the wheel speed detected by the wheel speed detecting means fluctuates at a constant or substantially constant cycle according to the traveling speed of the host vehicle, the host vehicle is in the vicinity of the lane line or on the lane line. The lane departure prevention apparatus according to claim 3, wherein the lane departure prevention apparatus detects that the vehicle is traveling on a road surface unevenness provided on the road.   The road surface unevenness detecting means is provided near the lane marking line or on the lane marking line when only one of the left and right wheels of the wheel speed detected by the wheel speed detection means fluctuates. 5. The lane departure prevention device according to claim 3, wherein the lane departure prevention device detects that the vehicle is traveling on an uneven road surface. Suspension state detection means for detecting the state of vertical movement of the suspension,
The road surface unevenness detecting means travels on the road surface unevenness provided near the lane marking line or on the lane marking line based on the state of vertical movement of the suspension detected by the suspension state detecting means. The lane departure prevention device according to claim 2, wherein the lane departure prevention device is detected.   Travel position detection means for detecting that the host vehicle is traveling on a road other than the road, and when the travel position detection means detects that the host vehicle is traveling on a road other than the road, the road surface unevenness detection means A lane departure prevention apparatus according to any one of claims 2 to 6, further comprising detection restriction means for restricting a detection operation by the vehicle. A traveling state detecting means for detecting the traveling speed of the own vehicle, the direction of the own vehicle with respect to the traveling lane, the position of the own vehicle with respect to the traveling lane, and the curvature of the traveling lane of the own vehicle;
The departure tendency detection means is based on the travel speed of the host vehicle detected by the travel state detection means, the direction of the host vehicle with respect to the travel lane, the position of the host vehicle with respect to the travel lane, and the curvature of the travel lane of the host vehicle. The lateral displacement of the host vehicle with respect to the traveling lane is calculated, and the host vehicle tends to deviate from the traveling lane when the absolute value of the lateral displacement with respect to the traveling lane of the vehicle in the future is equal to or greater than a predetermined lateral displacement limit value. The lane departure prevention device according to any one of claims 2 to 7 , wherein the lane departure prevention device is detected. The lane departure avoidance control means is configured to avoid the departure of the own vehicle from the traveling lane when the departure tendency detecting means detects that the own vehicle is deviating from the traveling lane as the lane departure avoidance control. According to the first braking / driving force control amount calculating means for calculating the braking / driving force control amount of each wheel so that the yaw moment is generated, and the braking / driving force control amount calculated by the first braking / driving force control amount calculating means. lane departure prevention apparatus according to any one of claims 2 to 8 in which the first braking-driving force control means for controlling the longitudinal force of each wheel, comprising the to Te. A traveling state detecting means for detecting the traveling speed of the own vehicle, the direction of the own vehicle with respect to the traveling lane, the position of the own vehicle with respect to the traveling lane, and the curvature of the traveling lane of the own vehicle;
The first braking / driving force control amount calculating means includes a traveling speed of the own vehicle detected by the traveling state detecting means, a direction with respect to the traveling lane of the own vehicle, a position with respect to the traveling lane of the own vehicle, and a curvature of the traveling lane of the own vehicle. The lateral displacement of the vehicle in the future with respect to the driving lane is calculated, and the target yaw moment to be generated in the vehicle is calculated according to the difference between the lateral displacement of the vehicle in the future with respect to the traveling lane and the lateral displacement limit value. 10. The lane departure prevention apparatus according to claim 9 , wherein a braking / driving force control amount of each wheel is calculated according to a yaw moment. The lane departure avoidance control means, as the vehicle control, of claims 2 to 10, characterized by controlling the braking force of each wheel as the yaw moment to direct the vehicle to the center of the traffic lane occurs The lane departure prevention apparatus according to any one of the preceding claims. The lane departure avoidance control means calculates the braking / driving force control amount of each wheel so as to generate a constant yaw moment that directs the host vehicle toward the center position of the traveling lane as the vehicle control, and the calculated braking control. The lane departure prevention apparatus according to claim 11 , wherein the braking / driving force of each wheel is controlled in accordance with a driving force control amount. The lane departure prevention control means according to any one of claims 2 to 10 , wherein the lane departure avoidance control means generates a steering torque for directing the host vehicle toward a center position of a traveling lane as the vehicle control. apparatus.

Images