JP3941677B2 - Lane departure prevention device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a lane departure prevention apparatus for preventing a departure when a host vehicle is about to depart from a traveling lane during traveling.
[0002]
[Prior art]
Conventionally, as such a lane departure prevention device, for example, it is determined that the host vehicle is likely to deviate from the traveling lane, and the driver can easily perform according to the lateral deviation amount of the traveling position of the host vehicle with respect to the reference position of the traveling lane. There is one that prevents a lane departure by outputting a steering control torque that can be overcome by a steering actuator (see, for example, Patent Document 1).
[0003]
Further, since this lane departure prevention device requires a steering actuator, the braking force or driving force of each wheel is controlled using, for example, an anti-skid control device or a driving force control device, and as a result, a yaw moment is applied to the vehicle. It may be possible to control the traveling direction or the traveling position of the own vehicle by generating it.
In such a lane departure prevention device, it is desired to always detect the lane. Therefore, for example, there is a method in which a steering angle is used as a road parameter, and a lane marker model such as a white line is set from the road parameter (see, for example, Patent Document 2).
[0004]
[Patent Document 1]
Japanese Patent Laid-Open No. 11-96497 [Patent Document 2]
Japanese Patent Laid-Open No. 11-296660
[Problems to be solved by the invention]
By the way, normally, in order to correctly detect a travel lane, it is necessary to detect lane markers such as white lines on both sides of the travel lane (the travel lane exists between two lane markers). Therefore, in the conventional lane departure prevention device, when the lane markers on both sides of the traveling lane cannot be detected, the lane departure prevention control is stopped because the traveling lane is not correctly detected. However, at least when the lane marker in the departure direction can be detected, the departure prevention control itself is established. Therefore, if the control is stopped in such a case, there is a deviation from the driver's feeling, and there is a sense of incongruity. It has become.
[0006]
The present invention has been developed in view of these various problems, and an object thereof is to provide a lane departure prevention device that can eliminate a sense of incongruity and eliminate a deviation from the driver's feeling. It is.
[0007]
[Means for Solving the Problems]
In order to solve the above problem, the lane departure prevention apparatus of the present invention detects the travel lane from the lane markers on both sides of the travel lane of the host vehicle, and detects that the host vehicle tends to depart from the travel lane. In addition, the vehicle behavior is controlled so that the yaw moment is generated in a direction that avoids the departure from the traveling lane of the own vehicle, and only the lane marker on one side of the traveling lane of the own vehicle can be detected, and the detected lane marker is When the lane marker is in the departure direction, behavior control of the vehicle that generates the yaw moment is performed.
[0008]
【The invention's effect】
Thus, according to the lane departure prevention apparatus of the present invention, when the travel lane is detected from the lane markers on both sides of the travel lane of the host vehicle, and when it is detected that the host vehicle tends to depart from the travel lane, The behavior of the vehicle is controlled so that the yaw moment is generated in a direction that avoids the departure from the traveling lane of the own vehicle, and only the lane marker on one side of the traveling lane of the own vehicle can be detected, and the detected lane marker is the departure direction Therefore, when the detected lane marker is in the deviating direction, there is no deviation from the driver's feeling when the lane marker is a lane marker. Can be wiped off.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, a first embodiment of a lane departure prevention apparatus of the present invention will be described with reference to the accompanying drawings.
FIG. 1 is a schematic configuration diagram of a vehicle illustrating an example of a lane departure prevention apparatus according to the present embodiment. This vehicle is a rear wheel drive vehicle equipped with an automatic transmission and a conventional differential gear, and the braking device can control the braking force of the left and right wheels independently of the front and rear wheels.
[0010]
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 boosted by the master cylinder 3 depends on the amount of depression of the brake pedal 1 by the driver. The brake fluid pressure control circuit 7 is interposed between the master cylinder 3 and the wheel cylinders 6FL to 6RR. In the braking fluid pressure control circuit 7, the braking fluid pressures of the wheel cylinders 6FL to 6RR can be individually controlled.
[0011]
The brake fluid pressure control circuit 7 uses a brake fluid pressure control circuit used for, for example, anti-skid control and traction control. In this embodiment, the brake fluid pressures of the wheel cylinders 6FL to 6RR are independently set. It is configured so that the pressure can be increased or decreased. The brake fluid pressure control circuit 7 controls the brake fluid pressures of the wheel cylinders 6FL to 6RR in accordance with a brake fluid pressure command value from a braking / driving force control unit 8 described later.
[0012]
In addition, the vehicle controls the driving torque to the rear wheels 5RL and 5RR, which are driving wheels, 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. The operating state control of the engine 9 can be controlled, for example, by controlling the fuel injection amount and the ignition timing, and can also be controlled by controlling the throttle opening at the same time. The drive torque control unit 12 can independently control the drive torque of the rear wheels 5RL and 5RR that are drive wheels. However, the drive torque command value from the braking / driving force control unit 8 described above can be controlled. When input, the drive wheel torque is controlled with reference to the drive torque command value.
[0013]
In addition, this vehicle includes a CCD camera 13 and a camera controller 14 as an external recognition sensor for detecting the position of the host vehicle in the traveling lane for determining the traveling lane departure prevention of the host vehicle. The camera controller 14 detects, for example, a lane marker such as a white line from a captured image in front of the host vehicle captured by the CCD camera 13 to detect a travel lane, and also the yaw angle φ of the host vehicle with respect to the travel lane, that is, the lane The direction of the host vehicle, the lateral displacement X from the center of the travel lane, the curvature β of the travel lane, the travel lane width L, and the like can be calculated. As will be described later, the camera controller 14 performs travel lane detection using a travel lane detection area for detecting lane markers and the like, and calculates the data for the detected travel lane.
[0014]
Further, the vehicle 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 A master cylinder pressure sensor 17 that detects the master cylinder pressure P _m , 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, rotational speeds of the wheels 5FL-5RR, wheel speed sensors 22FL~22RR for detecting a so-called wheel speed Vw _{i (i} = FL~RR), direction indicating switch 20 that detects a direction indicating operation by the direction indicator is provided, of which The detection signal is output to the braking / driving force control unit 8. Further, the yaw angle φ of the host vehicle with respect to the travel lane detected by the camera controller 14, the lateral displacement X from the center of the travel lane, the curvature β of the travel lane, the travel lane width L, and the like are controlled by the drive torque control unit 12. The driving torque Tw is also output to the braking / driving force control unit 8 together. If 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, the steering angle δ, 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.
[0015]
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 interruption every predetermined sampling time ΔT every 10 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.
[0016]
In this calculation process, first, in step S110, various data from the sensors, the controller, and the control unit are read. Specifically, the longitudinal acceleration Xg, lateral acceleration Yg, yaw rate φ ′ detected by each sensor, each wheel speed Vw _i , accelerator opening Acc, master cylinder pressure P _m , steering angle δ, direction indication switch signal, Further, the driving torque Tw from the driving torque control unit 12 is read. Further, in step S110, the combined, among the wheel speeds Vw _i'm read, before a non-driven wheel left and right wheel speeds Vw _FL, calculates the traveling velocity V of the vehicle from an average value of Vw _FR. At this time, the yaw angle φ of the host vehicle with respect to the travel lane, the lateral displacement X from the center of the travel lane, the curvature β of the travel lane, and the travel lane width L are not yet read from the camera controller 14.
[0017]
Next, the process proceeds to step S120, and a traveling lane detection area, which will be described later, specifically, based on the steering angle δ read in step S110, for example, using the method described in the above-mentioned JP-A-11-296660. Set the lane marker detection area, detect the lane marker on both sides of the lane on which the host vehicle is traveling based on the set lane marker detection area, and detect the lane on which the host vehicle is traveling using the lane marker The camera controller 14 is instructed to calculate the yaw angle φ of the host vehicle relative to the travel lane, the lateral displacement X from the center of the travel lane, the curvature β of the travel lane, and the travel lane width L, and the data Is read.
[0018]
Next, the process proceeds to step S130, where it is determined whether or not lane markers on both sides of the traveling lane of the host vehicle are detected in step S120. If both lane markers are detected, the process proceeds to step S140. Otherwise, the process proceeds to step S150.
In step S150, it is determined whether only one lane marker is detected in one of the traveling lanes of the host vehicle in step S120. If only one lane marker is detected, the process proceeds to step S160. Otherwise, the process proceeds to step S170.
[0019]
In step S160, it is determined whether or not the detected lane marker is a lane marker on the lane departure side of the host vehicle. If the detected lane marker is on the departure side, the process proceeds to step S140. If not, the process proceeds to step S170.
Here, the determination of the lane marker on the departure direction side or the countryside is, for example, determined to be the departure direction side when the following (1) or (2) is established, and otherwise determined not to be the departure direction side. .
[0020]
(1) The left lane marker is detected in step S120, and the estimated lateral displacement Xs calculated in step S190 described later at the time of the previous calculation is a positive value.
(2) The right lane marker is detected in step S120, and the estimated lateral displacement Xs calculated in step S190 described later at the time of the previous calculation is a negative value.
[0021]
In step S170, the departure prevention control permission flag F is set to the reset state “0”, and then the process proceeds to step S180.
In step S140, the departure prevention control permission flag F is set to “1”, and then the process proceeds to step S180.
In step S180, it is determined whether or not the departure prevention control permission flag F is set to “1”. If the departure prevention control permission flag F is set, the process proceeds to step S190. If not, the process proceeds to step S210.
[0022]
In step S190, a future estimated lateral displacement XS is calculated as a deviation estimated value, and then the process proceeds to step S200. Specifically, the yaw angle φ with respect to the traveling lane of the host vehicle, the lateral displacement X from the center of the traveling lane, the curvature β of the traveling lane, and the traveling speed V of the own vehicle calculated in step S110 are read. The estimated lateral displacement XS in the future is calculated according to the following two equations.
[0023]
XS = Tt × V × (φ + Tt × V × β) + X (2)
Here, Tt is the vehicle head time for calculating the forward gaze distance, and when the vehicle head time Tt is multiplied by the traveling speed V of the host vehicle, the front gaze distance is obtained. 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. As will be described later, in the present embodiment, when the estimated lateral displacement XS in the future is equal to or greater than a predetermined lateral displacement limit value, it is determined that the host vehicle may deviate from the driving lane or tend to deviate. It is.
[0024]
In step S200, the process proceeds to step S210 after determining whether or not the host vehicle tends to deviate from the driving lane. Specifically, when the absolute value | XS | of the estimated future lateral displacement as the departure estimated value calculated in step S190 is equal to or greater than the lateral displacement limit value X _C , the host vehicle tends to depart from the traveling lane. If there is, the departure determination flag _FLD is set, and if not, the departure determination flag _FLD is reset, assuming that the host vehicle does not have a departure tendency from the driving lane. When the lane change direction estimated by the input from the direction indicating switch 20 coincides with the departure direction of the host vehicle from the traveling lane, the departure determination flag _FLD is reset. Further, in this step S200, it may be determined whether or not to warn that the host vehicle tends to deviate from the traveling lane. Specifically, the absolute value | XS | of the future estimated lateral displacement as the deviation estimated value calculated in step S190 is calculated from the half value of the travel lane width L read in step S120. A method may be considered in which a warning is issued when the lateral displacement limit value X _{C obtained} by subtracting a half value of ₀ is exceeded, and a warning is not issued otherwise.
[0025]
In step S210, a target yaw moment M _S for preventing lane departure is calculated and set. Here, since only sets a target yaw moment M _S when the departure determination flag F _LD is set, when the departure determination flag F _LD is set, a proportional coefficient K ₁ determined by the vehicle specification Using the proportional coefficient K ₂ set according to the vehicle traveling speed V shown in FIG. 3, the estimated future lateral displacement XS calculated in the step S190, and the lateral displacement limit value X _C , the following 3 A target yaw moment M _S is calculated according to the equation.
[0026]
M _S = −K ₁ × K ₂ × (XS−X _C ) (3)
The target yaw moment M _S is set to “0” when the departure determination flag _FLD is in the reset state.
Next, the process proceeds to step S220, and the target braking fluid pressure P _{Si for} each wheel and the target driving force of the driving wheel are calculated. Specifically, the relative master cylinder pressure P _m read in step S110, when the wheel master cylinder pressure after based on front-rear braking force distribution and P _mR, the departure determination flag F _LD is in the reset state Sometimes, the target braking fluid pressures P _SFL and P _SFR to the wheel cylinders 6FL and 6FR of the front left and right wheels 5FL and 5FR are both the master cylinder pressure P _m , and the target braking to the wheel cylinders 6RL and 6RR of the rear left and right wheels 5RL and 5RR is performed. The fluid pressures P _SRL and P _SRR are both the rear wheel master cylinder pressure P _mR .
[0027]
On the other hand, even when the departure determination flag _FLD is set, the cases are classified according to the magnitude of the target yaw moment M _S calculated in step S210. That is, when the absolute value | M _S | of the target yaw moment is less than the predetermined value M _S0 , a difference is generated only in the braking force of the rear left and right wheels, and the absolute value | M _S | When it is greater than or _{equal to S0} , a difference is generated in the braking force between the front, rear, left and right wheels. Therefore, the front left and right wheel target braking fluid pressure difference ΔP _SF when the absolute value | M _S | of the target yaw moment is less than the predetermined value M _S0 is “0”, and the rear left and right wheel target braking fluid pressure difference ΔP _SR is It is given by equation (4). Similarly, the front left and right wheel target braking fluid pressure difference ΔP _SF when the absolute value | M _S | of the target yaw moment is equal to or greater than the predetermined value M _S0 is the following five equations, and the rear left and right wheel target braking fluid pressure difference ΔP _SR is It is given by the formula. In the equation, T is a tread (the same _applies to front and rear wheels), K _bF and K _bR are conversion coefficients for converting braking force into braking fluid pressure, and are determined by brake specifications.
[0028]
ΔP _SR = 2 × K _bR × | M _S | / T (4)
ΔP _SF = 2 × K _bF × (| M _S | −M _S0 ) / T (5)
ΔP _SR = 2 × K _bR × | M _S0 | / T (6)
Therefore, when the target yaw moment M _S is a negative value, that is, when the host vehicle is about to deviate to the left, the target braking fluid pressure P _Si to the wheel cylinders 6FL to 6RR is given by the following equation (7). .
[0029]
P _SFL = P _m
P _SFR = P _m + ΔP _SF
P _SRL = P _m
P _SRR = P _m + ΔP _SR (7)
On the other hand, when the target yaw moment M _S is a positive value, that is, when the host vehicle is about to deviate in the right direction, the target braking fluid pressure P _Si to the wheel cylinders 6FL to 6RR is expressed by the following eight formulas. Given.
[0030]
P _SFL = P _m + ΔP _SF
P _SFR = P _m
P _SRL = P _m + ΔP _SR
P _SRR = P _m ……… (8)
Further, in the present embodiment, the departure determination flag _FLD is set, and when the lane departure prevention control is performed, even if the accelerator operation is performed, the engine output is reduced so that the engine cannot be accelerated. Accordingly, the target driving torque Trq _DS when divergence determination flag F _LD is set, the value corresponding to the accelerator opening Acc is loaded in step S1, the target brake hydraulic pressure difference [Delta] P _SF of the front and rear wheels, [Delta] P _The value corresponding to the sum of _SR is subtracted. That is, the value according to the accelerator opening Acc is a driving torque for accelerating the host vehicle according to the accelerator opening Acc, and a value according to the sum of the target braking fluid pressure differences ΔP _SF and ΔP _SR of the front and rear wheels. Is a braking torque generated by the sum of the target braking fluid pressure differences ΔP _SF and ΔP _SR . Therefore, when the departure determination flag _FLD is set and the lane departure prevention control is performed, the engine torque is reduced by the braking torque generated by the sum of the target braking fluid pressure differences ΔP _SF and ΔP _SR. Become. The target driving torque Trq _DS when divergence determination flag F _LD is reset, the only driving torque amount for accelerating the vehicle in accordance with the accelerator opening Acc.
[0031]
Next, the process proceeds to step S230, where the target brake fluid pressure of each wheel calculated in step S220 is output to the brake fluid pressure control circuit 7, and the target drive torque of the drive wheels is output to the drive torque control unit. After output to 12, the program returns to the main program.
Here, the operation of the lane marker detection will be described. In this embodiment, for example, as shown in FIG. 4, a lane marker detection area for detecting a lane marker such as a white line is set from an image captured by the CCD camera 13. Specifically, if a lane marker is detected (scanned) over the entire captured image, the calculation load is large and time is required. Therefore, a smaller detection area (so-called window) is set in an area where a lane marker is likely to exist, and the lane marker is detected within the detection area. In general, if the direction of the host vehicle with respect to the lane changes, the position of the lane marker displayed in the image also changes. The detection area is set in the area where the lane marker in the box will be projected. Then, for example, a filtering process that makes the boundary between the lane marker and the road surface stand out is performed. As shown in FIG. 5, a straight line that seems to be the boundary between the lane marker and the road surface is detected in each lane marker detection region, (Lane marker candidate point) is detected as a representative part of the lane marker. In the example of FIG. 5, the highest point of the straight line detection result is detected as a lane marker candidate point. When the number of lane marker candidate points for one lane marker is equal to or greater than a predetermined value set in advance, it is assumed that the detected lane marker is correct. Conversely, when the number of lane marker candidate points is less than the predetermined value, the lane marker is not detected as being incorrect. Furthermore, if the total number of lane marker candidate points of the lane markers on both sides is not equal to or greater than a predetermined value, it is assumed that the lane markers on both sides are not correctly detected.
[0032]
According to the calculation process of FIG. 2, as shown in FIG. 6, when the lane markers on both sides of the traveling lane are detected, the departure prevention control permission flag F is set, and the driver is not intentionally changing the lane. When the estimated lateral displacement XS in the future becomes equal to or greater than the lateral displacement limit value X _C , it is determined that the host vehicle has a tendency to deviate from the driving lane, and the departure determination flag _FLD is set. A target yaw moment M _S is calculated based on the difference between the lateral displacement XS and the lateral displacement limit value X _C, and the braking force of each wheel is controlled so that the target yaw moment M _S is achieved. As a result, for example, when the steering input is small, a yaw moment that prevents the lane departure is generated in the vehicle and the lane departure is prevented, and the traveling speed of the vehicle is reduced by the braking force. Can be prevented. Further, in this embodiment, while the lane departure prevention control is being performed, the engine output torque is reduced and the traveling speed of the host vehicle is reduced. Therefore, it is possible to more safely prevent the lane departure. It becomes.
[0033]
Further, in this embodiment, even when only one lane marker on the traveling lane can be detected, the departure prevention control permission flag F is set when the lane marker is a lane marker on the departure side of the own vehicle. Similarly, lane departure prevention control is performed. Thereby, when only the lane marker in the departure direction can be detected, the lane departure prevention control is continued, which matches the driver's feeling and does not feel strange.
[0034]
From the above, each sensor and camera controller 14 of FIG. 1 and steps S110 and S120 of the calculation process of FIG. 2 constitute the running state detecting means of the present invention. Similarly, step S120 of the calculation process of FIG. 2 constitutes a lane detection means and a lane marker detection means, and steps S190 and S200 of the arithmetic processing of FIG. 2 constitute a departure determination means, and steps S130 to S230 of the arithmetic processing of FIG. 2 and the brake fluid pressure control circuit of FIG. 7 and the drive torque control unit 12 constitute vehicle behavior control means, step S220 of the arithmetic processing of FIG. 2 constitutes braking / driving force control amount calculation means, step S230 of the arithmetic processing of FIG. 2 and braking fluid of FIG. The pressure control circuit 7 and the drive torque control unit 12 constitute braking / driving force control means.
[0035]
Next, a second embodiment of the lane departure prevention apparatus of the present invention will be described. The vehicle schematic configuration in this embodiment is the same as that of FIG. 1 of the first embodiment.
In the present embodiment, the arithmetic processing performed by the braking / driving force control unit 8 is changed from that of FIG. 2 of the first embodiment to that of FIG. The arithmetic processing in FIG. 7 is similar to the arithmetic processing in FIG. 2 and includes equivalent steps. Therefore, the same steps are denoted by the same reference numerals, and detailed description thereof is omitted. As a specific difference, step S161 is interposed between step S160 and step S140.
[0036]
In step S161, it is determined whether or not the number of lane marker candidate points of the lane marker on the side that could not be detected (lost in the figure) is greater than or equal to a predetermined value. The process proceeds to step S140, and if not, the process proceeds to step S170. The predetermined value of the number of lane marker candidate points here is different from the predetermined value for determining that the lane marker is correctly detected, and indicates a smaller value.
[0037]
According to this arithmetic processing, in addition to the operation of the first embodiment, when only one of the lane markers can be detected, if the number of lane marker candidate points that cannot be detected is equal to or greater than a predetermined value, departure prevention control is performed in step S140. The permission flag F is set, and lane departure prevention control is performed as in the first embodiment. Here, when the lane marker is a white dotted line, even if the lane marker is correctly detected, the lane marker candidate point may be less than a predetermined value indicating whether the lane marker is correctly detected. Therefore, even if only one lane marker can be detected correctly, if the number of lane marker candidates on the opposite side is greater than or equal to a predetermined value, that is, if the probability of the lane marker is large, the lane departure prevention control continues and the lane of the host vehicle is continued. Deviations can be reliably suppressed and prevented.
[0038]
In addition to this, the probability of the lane marker can be determined by, for example, the time during which the lane markers on both sides of the traveling lane are detected. That is, for example, when the lane marker on both sides of the traveling lane in which the host vehicle is running is detected, the lane marker detection counter CNT on both sides is incremented, and when only one lane marker can be detected, the lane marker detection counter CNT on both sides is detected. There may be set the departure prevention control permission flag F as long predetermined value CNT ₀ or more. Normally, when the vehicle is about to depart from the traveling lane, as shown in FIG. 4 or FIG. 6, the lane markers on both sides of the traveling lane are detected at first, and only the lane marker in the deviating direction is eventually detected. Become. Therefore, if the detection time of the lane markers on both sides is long and only one of the lane markers can be detected after that, the vehicle is about to deviate in that direction. Can be prevented.
[0039]
From the above, each sensor and camera controller 14 in FIG. 1 and steps S110 and S120 of the calculation process of FIG. 7 constitute the running state detecting means of the present invention. Similarly, step S120 of the calculation process of FIG. 7 constitutes a lane detection means and a lane marker detection means, step S161 of the arithmetic processing in FIG. 7 constitutes a lane marker probability detection means, and steps S190 and S200 of the arithmetic processing in FIG. 7 constitute a departure determination means. Steps S130 to S230 in FIG. 7 and the braking fluid pressure control circuit 7 and the driving torque control unit 12 in FIG. 1 constitute vehicle behavior control means, and step S220 in the arithmetic processing in FIG. 7 constitutes braking / driving force control amount calculation means. 7 and step S230 of the arithmetic processing in FIG. 7 and the brake fluid pressure control circuit 7 in FIG. Dynamic torque control unit 12 constitute a longitudinal force control means.
[0040]
Next, a third embodiment of the lane departure prevention apparatus of the present invention will be described. The vehicle schematic configuration in this embodiment is the same as that of FIG. 1 of the first embodiment.
In the present embodiment, the arithmetic processing performed by the braking / driving force control unit 8 is changed from that of FIG. 2 of the first embodiment to that of FIG. The calculation process of FIG. 8 is similar to the calculation process of FIG. 2 and includes equivalent steps. Therefore, the same steps are denoted by the same reference numerals, and detailed description thereof is omitted. Specifically, step S132 is interposed between step S130 and step S140, step S164 is interposed between step S160 and step S140, and step S210 is changed to step S211. has been edited.
[0041]
In step S132, the target yaw moment proportional coefficient k is set to “1”, and then the process proceeds to step S140.
In step S164, the target yaw moment proportional coefficient k is set to a predetermined value k ₀ smaller than “1”, and then the process proceeds to step S140.
Then, in the step S211, proceeds by multiplying the target yaw moment proportional coefficient k to the target yaw moment M _S calculated by the three equations, set its value to the new target yaw moment M _S in the step S220 To do.
[0042]
According to this calculation processing, in addition to the operation of the first embodiment, when only one of the lane markers can be detected and the lane marker is a lane marker on the departure side, the predetermined value k ₀ smaller than “1” is used. target yaw moment proportional coefficient k is set to become the target yaw moment M _S is set by multiplying the target yaw moment proportional coefficient k. That is, since the target yaw moment M _S is a control output of the lane departure prevention apparatus of the present embodiment, by changing the gain to a small value, the control output when only one lane marker can be detected is used when the lane markers on both sides are detected. It will be adjusted smaller than that. As described above, when only one lane marker on the driving lane can be detected and the lane marker is a lane marker on the departure side, it is desirable to continue the lane departure prevention control. There is no substitute for not detecting completely accurately. Therefore, when detecting a lane marker on one side, it is possible to perform appropriate lane departure prevention control under such circumstances by continuing the lane departure prevention control while reducing the control output as in this embodiment.
[0043]
In the present embodiment, the gain made up of the target yaw moment proportional coefficient k is changed stepwise, but it may be changed continuously.
In addition to this, the control output can be reduced by reducing the number of control executions and the control duration.
From the above, each sensor and camera controller 14 of FIG. 1 and steps S110 and S120 of the arithmetic processing of FIG. 8 constitute the traveling state detecting means of the present invention. Similarly, step S120 of the arithmetic processing of FIG. The lane detecting means and the lane marker detecting means are configured, and steps S190 and S200 of the arithmetic processing in FIG. 8 constitute a departure determining means, and steps S130 to S230 of the arithmetic processing in FIG. 8 and the braking fluid pressure control circuit in FIG. 7 and the drive torque control unit 12 constitute vehicle behavior control means, step S220 of the calculation process of FIG. 8 constitutes braking / driving force control amount calculation means, step S230 of the calculation process of FIG. 8 and braking fluid of FIG. The pressure control circuit 7 and the drive torque control unit 12 constitute braking / driving force control means.
[0044]
Next, a fourth embodiment of the lane departure prevention apparatus of the present invention will be described. The vehicle schematic configuration in this embodiment is the same as that of FIG. 1 of the first embodiment.
In the present embodiment, the arithmetic processing performed by the braking / driving force control unit 8 is changed from that of FIG. 2 of the first embodiment to that of FIG. The arithmetic processing in FIG. 9 is similar to the arithmetic processing in FIG. 2 and includes equivalent steps. Therefore, the same steps are denoted by the same reference numerals, and detailed description thereof is omitted. Specifically, step S133 is interposed between step S130 and step S140, and step S165 is interposed between step S160 and step S140.
[0045]
In step S133, the lateral displacement limit value X _C for determining the departure tendency is set as the lateral displacement limit value X _C as it is, and then the process proceeds to step S140.
In step S165, the lateral displacement limit value X _C for determining the departure tendency is set to a predetermined value X _C0 larger than the lateral displacement limit value X _C , and then the process proceeds to step S140.
[0046]
According to this arithmetic processing, in addition to the operation of the first embodiment, when only one lane marker on the traveling lane can be detected and the lane marker is a lane marker on the departure side, the original lateral displacement limit value X _A predetermined value X _C0 larger than _C is set as a new lateral displacement limit value X _C, and the deviation tendency is determined using the lateral displacement limit value X _C. In this case, the absolute value of future estimated lateral displacement as the deviation estimate | XS | is, the departure flag as the vehicle when the at lateral displacement limit value X _C or more is in a deviation tendency from the traffic lane F _LD Therefore, if the lateral displacement limit value X _C becomes a large value, it is difficult to determine a tendency to deviate, and the intervention timing of the lane departure prevention control is delayed, that is, the target yaw moment M _S becomes “0”. Further, the target yaw moment M _S calculated by the above equation 3 also becomes a small value, and the control output is adjusted to be small as in the third embodiment. That is, since the target yaw moment M _S is a control output of the lane departure prevention apparatus of the present embodiment, the control output when only one side lane marker can be detected can be obtained by changing the threshold greatly when the lane markers on both sides are detected. It will be adjusted smaller than that. As described above, when only one lane marker on the traveling lane can be detected and the lane marker is a lane marker on the departure side, it is desirable to continue the lane departure prevention control. There is no substitute for not detecting completely accurately. Therefore, when detecting a lane marker on one side, it is possible to perform appropriate lane departure prevention control under such circumstances by continuing the lane departure prevention control while reducing the control output as in this embodiment.
[0047]
In the present embodiment, the threshold value of the lateral displacement limit value X _C is changed stepwise, but it may be changed continuously.
In addition to this, the control output can be reduced by reducing the number of control executions and the control duration.
From the above, each sensor and camera controller 14 of FIG. 1 and steps S110 and S120 of the calculation process of FIG. 9 constitute the running state detecting means of the present invention, and similarly, step S120 of the calculation process of FIG. 9 constitutes lane detection means and lane marker detection means, and step S190 and step S200 of the arithmetic processing of FIG. 9 constitute departure judgment means, and steps S130 to S230 of the arithmetic processing of FIG. 9 and the brake fluid pressure control circuit of FIG. 7 and the drive torque control unit 12 constitute vehicle behavior control means, step S220 of the calculation process of FIG. 9 constitutes braking / driving force control amount calculation means, step S230 of the calculation process of FIG. 9 and braking fluid of FIG. The pressure control circuit 7 and the drive torque control unit 12 constitute braking / driving force control means.
[0048]
In the embodiment described above, the lateral displacement limit value X _C that is the threshold for judging the lane departure is calculated from the vehicle width and the traveling lane width. For example, the traveling lane width of a highway in Japan is determined to be 3.35 m. For example, this may be fixed at 0.8 m.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram showing an example of a vehicle equipped with a lane departure prevention apparatus of the present invention.
FIG. 2 is a flowchart showing a first embodiment of information calculation processing executed in the braking / driving force control unit of FIG. 1;
FIG. 3 is a control map used for the arithmetic processing of FIG. 2;
FIG. 4 is an explanatory diagram of the operation of the arithmetic processing in FIG. 2;
FIG. 5 is an explanatory diagram of the operation of the arithmetic processing in FIG. 2;
6 is an explanatory diagram of the operation of the arithmetic processing in FIG. 2. FIG.
FIG. 7 is a flowchart showing a second embodiment of information calculation processing executed in the braking / driving force control unit of FIG. 1;
FIG. 8 is a flowchart showing a third embodiment of information calculation processing executed in the braking / driving force control unit of FIG. 1;
FIG. 9 is a flowchart showing a fourth embodiment of the information calculation process executed in the braking / driving force control unit of FIG. 1;
[Explanation of symbols]
6FL to 6RR are wheel cylinders 7, braking fluid pressure control circuit 8, braking / driving force control unit 9, engine 12, driving torque control unit 13, CCD camera 14, camera controller 15, acceleration sensor 16, yaw rate sensor 17, master cylinder pressure The sensor 18 is an accelerator opening sensor 19, the steering angle sensor 20 is a direction indicator switch 22FL to 22RR, and a wheel speed sensor.

Claims (7)

Travel lane detection means for detecting the travel lane of the host vehicle, travel state detection means for detecting the travel state of the host vehicle, the travel lane detected by the travel lane detection means, and the travel state detected by the travel state detection means Detecting when the vehicle is in a tendency to deviate from the driving lane and when the vehicle is in a tendency to deviate from the driving lane. Vehicle behavior control means for controlling the behavior of the vehicle so that the yaw moment is generated in a direction that avoids the departure of the own vehicle from the travel lane according to the travel state, and the travel lane detection means a lane marker detecting means for detecting a lane marker for detecting a lane marker on either side of the traffic lane of the vehicle, the lane marker detected by the detection means lane marker is the traffic lane of the vehicle And a lane departure direction lane markers detection means for detecting that the lane markers et deviation direction, the vehicle behavior control means, the lane marker and the deviation direction can only be detected one side of the lane markers in the detection means the traffic lane of the vehicle A lane departure prevention apparatus characterized in that, when the lane marker detection means detects that the detected lane marker is a lane marker in a departure direction from the traveling lane of the host vehicle, the behavior control of the vehicle is performed. The vehicle behavior control means comprises a lane marker on one side of the traveling lane of the own vehicle by the lane marker detecting means, comprising lane marker probability detecting means for detecting the likelihood of the lane marker of the traveling lane of the own vehicle detected by the lane marker detecting means. 2. The lane departure prevention apparatus according to claim 1, wherein when the vehicle can only be detected, behavior control of the vehicle is performed based on the likelihood of the lane marker detected by the lane marker probability detection unit. The lane marker detection means detects a lane marker in a plurality of different areas in the captured image and identifies a representative part of the lane marker in each area, and the lane marker probability detection means detects each lane marker detection means detected by the lane marker detection means. 3. The lane departure prevention apparatus according to claim 2, wherein the likelihood of the lane marker is detected based on the number of representative parts of the lane marker in the region. 2. The vehicle behavior control means, when the lane marker detection means can detect only a lane marker on one side of the traveling lane of the host vehicle, makes the control output smaller than when the lane markers on both sides are detected. 4. A lane departure prevention apparatus according to any one of claims 1 to 3. The lane departure prevention apparatus according to claim 4, wherein the vehicle behavior control means reduces the control output by changing a control gain. The lane departure prevention apparatus according to claim 4 or 5, wherein the vehicle behavior control means reduces a control output by changing a control threshold value. The vehicle behavior control means includes a braking / driving force control amount calculating means for calculating a braking / driving force control amount for each wheel so that a yaw moment is generated in a direction that avoids a departure from the traveling lane of the host vehicle, and the braking / driving force control amount calculating means. 7. The braking / driving force control means for controlling the braking / driving force of each wheel according to the braking / driving force control amount calculated by the driving force control amount calculating means. The lane departure prevention apparatus described.

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