JP4423930B2 - Lane departure prevention device - Google Patents

Description

  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.

As a conventional lane departure prevention device, either the distance (lateral deviation amount) from the center of the traveling lane of the vehicle traveling position or the angle (yaw angle deviation amount) formed by the traveling prediction course with respect to the traveling lane has a predetermined value. It is known that a lane departure is determined based on whether or not the vehicle is exceeded, and a yaw moment is given to the vehicle by controlling the brake to prevent the lane departure and a warning is given to the driver through this yaw moment (for example, Patent Document 1).
JP 2000-33860 A (page 3, FIG. 6)

However, in the above conventional lane departure prevention device, since the lane departure is judged from the surrounding environment and the traveling situation, the change in the vehicle behavior due to disturbance on the traveling lane such as unevenness and friction coefficient of the traveling lane. There is an unresolved problem that it is not possible to respond appropriately to the resulting lane departure.
Accordingly, the present invention has been made paying attention to the unsolved problems of the above-described conventional example, and can improve the lane departure prevention performance even when the change in the vehicle behavior due to the disturbance on the traveling lane is taken into consideration. The object is to provide a deviation prevention device.

In order to achieve the above object, a lane departure prevention apparatus according to the present invention detects a traveling state of the host vehicle by a traveling state detection unit, and based on the traveling state detected by the traveling state detection unit by a disturbance influence detection unit. Then, the influence of the disturbance of the road surface on the own vehicle lane of each wheel is detected, and the deviation judgment means detects the running condition detected by the running condition detection means and the disturbance influence of each wheel detected by the disturbance influence detection means. Based on the above, when it is determined that the host vehicle tends to deviate from the traveling lane, and the departure determining means determines that the host vehicle tends to deviate from the traveling lane, The host vehicle is controlled in a direction to avoid a departure according to the running state detected by the running state detecting means and the disturbance influence of each wheel detected by the disturbance influence detecting means.
Further, when the yaw control amount calculation means detects that the own vehicle tends to deviate from the driving lane by the departure determination detection means, the traveling state detected by the traveling state detection means and the disturbance influence detection means The first braking / driving force control amount of each wheel is calculated so that the yaw moment is generated in the direction avoiding the departure from the traveling lane of the own vehicle in accordance with the disturbance influence of each wheel detected in step In the control amount calculation means, the braking force of each wheel is generated so that the braking force is generated in the host vehicle according to the running state detected by the running state detection means and the disturbance influence of each wheel detected by the disturbance influence detection means. A second braking / driving force control amount is calculated, and the braking / driving force control means is responsive to the first and second braking / driving force control amounts calculated by the yaw control amount calculation means and the braking control amount calculation means. Controls the braking / driving force of each wheel.
The braking control amount calculating means generates a larger braking force in the host vehicle when the disturbance influence detecting means detects the disturbance influence of the front and rear wheels than when the disturbance influence of only the front wheels is detected. Thus, the second braking / driving force control amount of each wheel is calculated.
In the lane departure prevention apparatus according to the present invention, the yaw control amount calculation means performs yaw control on the rear wheel that is a non-disturbance influence wheel when the disturbance influence detection means detects a disturbance influence only on the front wheels. Thus, the first braking / driving force control amount of each wheel is calculated.
Further, in the lane departure prevention apparatus according to the present invention, the traveling state detection means calculates an angle formed by the traveling lane and the longitudinal axis of the own vehicle, a lateral displacement of the own vehicle with respect to the traveling lane, and a curvature of the traveling lane of the own vehicle. And the yaw control amount calculating means includes target yaw moment calculating means for calculating a target yaw moment to be generated in the vehicle in accordance with the running state detected by the running state detecting means, and the target yaw moment calculating means The first braking / driving force control amount to be generated in each wheel is calculated according to the target yaw moment calculated in (1).
When the target yaw moment calculating means determines that the lane change determining means determines that there is an intention to change lanes during the influence of disturbance, and the vehicle determines when there is an intention to change lanes before the influence of disturbances, The target yaw moment is calculated so that is returned to the posture before the influence of the disturbance.

According to the present invention, it is determined that the host vehicle tends to deviate from the driving lane according to the change in the vehicle behavior due to the disturbance of the road surface on the driving lane. Even when the vehicle behavior changes due to the disturbance of the vehicle and the vehicle tends to deviate from the vehicle lane, it is possible to appropriately avoid the lane departure and to perform the departure prevention control without causing the driver to feel uncomfortable.
In addition, when the front and rear wheels are affected by disturbance, the braking force in the deceleration control is set larger than when only the front wheels are affected by disturbance, so that lane departure can be prevented accurately.
Furthermore, when only the front wheels are affected by disturbance, yaw control is performed on the rear wheels, which are non-disturbance-affected wheels, so that the wheel to be braked becomes insufficient in grip and the yaw moment in yaw control is insufficient. The resulting lane departure can be prevented.
Furthermore, when there is an intention to change the lane before the influence of the disturbance, the yaw control is performed so that the vehicle is returned to the posture before the influence of the disturbance, so that the lane can be changed smoothly.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a schematic configuration diagram of a first embodiment of the present invention. 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 (braking fluid pressure) of the left and right wheels independently of the front and rear wheels.
In the figure, reference numeral 1 is a brake pedal, 2 is a booster, 3 is a master cylinder, 4 is a reservoir, 9 is an engine, and 10 is an automatic transmission. Normally, the master pedal depends on the amount of depression of the brake pedal 1 by the driver. The brake fluid pressure boosted by the cylinder 3 is supplied to the wheel cylinders 6FL to 6RR of the front wheels 5FL, 5FR and the rear wheels 5RL, 5RR. Further, a braking fluid pressure control circuit 7 is interposed between the master cylinder 3 and each wheel cylinder 6FL-6RR. The braking fluid pressure control circuit 7 includes a braking fluid for each wheel cylinder 6FL-6RR. It is also possible to control the pressure individually.

  The brake fluid pressure control circuit 7 uses a brake fluid pressure control circuit used for, for example, anti-skid control or 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 control unit 8 described later.

  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 a lane marker by detecting a lane marker such as a road marking line from a captured image in front of the host vehicle captured by the CCD camera 13, and further detects the yaw angle Φ of the host vehicle with respect to the lane of travel, The lateral displacement X from the center of the lane, the curvature ρ of the traveling lane, the lane width L, and the like can be calculated, and these calculation signals are output to the control unit 8.

The vehicle includes a navigation system 15 that detects longitudinal acceleration Yg, lateral acceleration Xg, yaw rate φ, and road information generated in the host vehicle, and a master cylinder that detects an output pressure of the master cylinder 3, that is, a so-called master cylinder pressure Pm. A pressure sensor 16, a steering angle sensor 17 for detecting a steering angle δ of the steering wheel 19, wheel speed sensors 21FL to 21RR for detecting a rotation speed of each wheel 5FL to 5RR, that is, a so-called wheel speed Vw _j (j = FL to RR), A direction indicating switch 22 for detecting a direction indicating operation by the direction indicator, and stroke sensors 23FL to 23RR for detecting the vertical stroke amount St _j (j = FL to RR) of each wheel 5FL to 5RR are provided. Output to the control unit 8.

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 Xg, 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.
Further, a warning device 24 is provided in front of the driver's seat to present a warning to the driver in response to an alarm signal AL from the control unit 8 when a deviation from the driving lane is detected. Built-in speaker for generating buzzer sound.

Next, the lane departure prevention control process performed by the control unit 8 will be described with reference to the flowchart of FIG. This lane departure prevention control process is executed by, for example, a timer interrupt process every 10 msec.
In this lane departure prevention control process, first, in step S1, various data from the respective sensors and controllers are read. Specifically, each wheel speed Vw _j detected by each sensor, master cylinder pressure Pm, steering angle δ, direction indicating switch signal WS, stroke amount St _j , vehicle yaw angle Φ with respect to the travel lane from the camera controller 14 The lateral displacement X from the center of the traveling lane and the curvature ρ of the traveling lane are read.

Next, the process proceeds to step S2, and the vehicle speed V of the host vehicle is calculated from the average value of the front left and right wheel speeds Vw _FL and Vw _FR which are non-driven wheels among the wheel speeds Vw _{FL to} Vw _RR read in step S1. calculate.
V = (Vw _FL + Vw _FR ) / 2 (1)
Next, in step S3, the influence by the disturbance on the own vehicle traveling lane is determined. When affected by disturbances on the vehicle lane, yaw moment is generated due to a decrease in grip of a certain wheel, and the traveling direction changes. Here, the disturbance on the traveling lane includes unevenness on the road surface (unpaved portion, etc.) and a low friction coefficient road (wet road surface, manhole in rainy weather, fallen leaves on the road surface, gathering of pebbles, etc.).

Therefore, the presence / absence of a disturbance effect due to unevenness on the road surface is determined based on the stroke amount St _j, and the presence / absence of a disturbance effect due to the low μ road is determined based on the slip rate Sd _j . If it is determined that the vehicle is affected by disturbance on these lanes, it is determined that the subsequent predetermined time is affected by the disturbance.
Next, in step S4, based on the lateral displacement X, the amount of change dX of the lateral displacement X, and the distance to the lane (L / 2-X), the departure until the vehicle departs based on the following equation (2) The predicted time T _out is calculated, and the process proceeds to step S5.
T _out = (L / 2−X) / dX (2)

The departure prediction time T _out may be predicted based on the yaw angle Φ of the host vehicle, the curvature ρ of the traveling lane, the yaw rate φ of the vehicle, the steering angle δ, and the like.
In step S5, the calculated estimated time of departure T _out it is determined whether deviation determination threshold Ts is smaller than in step S4, T _out ≧ when Ts is, the step S6 it is determined that the vehicle is not in the deviation tendency , And the departure determination flag _Fout is reset to “0” which means that there is no departure tendency, and the operation proceeds to step S11 described later.

On the other hand, when the determination result in step S5 is T _out <Ts, it is determined that the host vehicle has a tendency to deviate and the process proceeds to step S7, which means that the deviation determination flag F _out has a tendency to deviate from “1”. Set to step S8.
In step S8, the sign of the lateral displacement X is determined. When X ≧ 0, it is determined that the host vehicle is shifted to the left from the center of the traveling lane, the process proceeds to step S9, and the departure direction _Dout is on the left side. This is set to “1” which means that the process proceeds to step S11 described later.

When the determination result of step S8 is X <0, the process proceeds to step S10, the departure direction _Dout is set to “2” which means the right side, and the process proceeds to step S11.
In this step S11, it is determined whether or not the driver intends to change the lane. This determination is made based on the direction indicating switch signal WS and the steering angle δ, and the direction determined by the sign of the direction indicating switch signal WS when the direction indicating switch 22 is in the on state matches the departure direction D _out. If so, it is determined that the lane change is intentional to the driver.

Further, when the direction indicating switch 22 is in the OFF state, the steering angle δ is equal to or larger than the preset steering angle set value δ _S and the steering angle change amount Δδ is equal to or larger than the preset change amount set value Δδ _S. If the direction and the departure direction match, it is determined that the lane change is intentional to the driver.
Here, a case has been described in which the determination of whether or not the driver intends to change lanes is made based on the steering angle and the amount of change in steering angle, but the intention to change lanes may be determined based on the steering torque. .

If it is determined in step S11 that there is no intention to change lanes, the process proceeds to step S12, and the lane change flag F _ch is set to “0” indicating that the driver does not intend to change lanes. After resetting, the process proceeds to step S13, and it is determined whether or not the departure determination flag F _out is set to “1”. When F _out = 0, the process proceeds to step S18 to be described later, and when F _out = 1, the process proceeds to step S14 to output an alarm signal AL to the alarm device 24 to activate the alarm.

Next, in step S15, the target yaw moment is calculated by the following equation (3), and then the process proceeds to step S21 described later.
Ms = K ₁ · X + K ₂ · dX (3)
Here, K ₁ and K ₂ are gains that vary according to the vehicle speed V.
On the other hand, when it is determined in step S11 that there is an intention to change lanes, the process proceeds to step S16, and the lane change flag F _ch is set to “1” indicating that the driver intends to change lanes. Then, the process proceeds to step S17, which means that the uneven road flag Fr _j or the low μ road flag Fm _j is affected by disturbance on the travel lane in the travel lane situation determination processing in step S3. It is determined whether or not 1 ″ is set.

When the determination result of step S17 is Fr _j ≠ 1 and Fm _j ≠ 1, the process proceeds to step 18 and the departure determination flag _Fout is reset to “0”, and then the process proceeds to step S21 described later. If the determination result in step S17 is Fr _j = 1 or Fm _j = 1, the process proceeds to step S19, and the driver intentionally changes the lane before receiving a disturbance on the traveling lane. It is determined whether it has been.

This determination is made based on whether or not the lane change flag F _ch before the disturbance on the traveling lane is set to “1”, and the lane change flag F _ch before the influence of the disturbance is reset to “0”. Sometimes, it is determined that there is no intention to change the lane, and the process proceeds to step S18.
When the lane change flag F _ch before the influence of the disturbance is set to “1” as a result of the determination at the step S19, it is determined that the intention to change the lane before the influence of the disturbance, and the process proceeds to the step S20. After calculating the target yaw moment by the following equation (4), the process proceeds to step S21.

Ms = K ₃ (Φ ₂ −Φ ₁ ) + K ₄ × X + K ₅ × ρ (4)
Here, K ₃ , K ₄ , and K ₅ are gains that vary according to the vehicle speed V, and Φ ₁ and Φ ₂ are yaw angles before and after being affected by the disturbance.
In step S21, a target brake hydraulic pressure calculation process is performed to calculate a target brake hydraulic pressure Ps _j for each wheel according to the departure determination flag F _out , the target yaw moment Ms, and the master cylinder hydraulic pressure Pm.

Then, the processing proceeds to step S22, to return from the output of the target brake hydraulic pressures Ps _FL ~Ps _RR calculated at step S21 to the brake hydraulic control circuit 7 to end the timer interrupt process to a predetermined main program .
Further, in step S3, performs driving lane on status determination process shown in FIG. 3, first, in step S31, the stroke amount St _j of each wheel detected by the stroke sensor 23, the stroke speed calculated from the stroke amount St _j It is determined whether or not the vehicle is affected by unevenness on the road surface using St _j ′.

This determination is made based on whether or not the stroke amount St _j and the stroke speed St _j ′ are equal to or greater than the preset determination threshold values St _S and Sv _S , and St _j ≧ St _S and St _j ′ ≧ Sv. When it is _S , it is determined that the wheel is affected by unevenness on the road surface, and the process proceeds to step S32.
In step S32, an uneven effect flag Fr _j, means that the disturbed effect while set to "1", and sets deviation judgment threshold Ts in the normal lane departure determination threshold value smaller than Ts1, the braking determination threshold Tr Is set to a value Tr1 smaller than the normal braking determination threshold value, and then the traveling lane situation determination process is terminated, and the process returns to a predetermined main program.

On the other hand, when the determination result in step S31 is St _j <St _S or St _j ′ <Sv _S , the process proceeds to step S33, and the unevenness influence flag Fr _j is set to “1” in the previous sampling. It is determined whether or not.
Then, when Fr _j = 0, the process proceeds to step S36 to be described later, and when Fr _j = 1, the process proceeds to step S34 to determine whether or not a predetermined time has elapsed since the influence of the unevenness on the road surface. judge. When the predetermined time has not elapsed, the traveling lane situation determination process is terminated with Fr _j = 1, and the process returns to the predetermined main program.

On the other hand, when a predetermined time has elapsed, the process proceeds to step S35, the transition from reset to the uneven effect flag Fr _j "0" in step S36.
At step S36, by using a slip ratio Sd _j of each wheel calculated by each wheel speed and the vehicle speed, it determines whether the vehicle is affected by the low friction coefficient road (low μ road).
This determination is performed by determining whether or not the slip ratio Sd _j is preset determination threshold Sd _S above, when a Sd _j ≧ Sd _S, the wheels determines that are affected by low μ road Then, the process proceeds to step S37.

In step S37, the low μ influence flag Fm _j is set to “1” which means that it is affected by a disturbance, and the departure judgment threshold Ts is set to a value Ts2 (Ts2 <Ts1) smaller than the normal departure judgment threshold. Then, after setting the braking determination threshold value Tr to a value Tr2 (Tr2 <Tr1) smaller than the normal braking determination threshold value, the traveling lane situation determination processing is terminated and the routine returns to a predetermined main program.

On the other hand, when the determination result of step S36 is Sd _j <Sd _S , the process proceeds to step S38 to determine whether or not the low μ influence flag Fm _j is set to “1” in the previous sampling. .
Then, when it is Fm _j = 0, exit left traffic lane on status determination process Fm _j = 0 returns to the predetermined main program, when it is Fm _j = 1, the process proceeds to step S39, the low It is determined whether or not a predetermined time has passed since the influence of the μ road.

If the determination result in step S39 is that the predetermined time has not elapsed, the driving lane situation determination process is terminated with Fm _j = 1, the process returns to the predetermined main program, and when the predetermined time has elapsed, the process proceeds to step S40. After the transition, the low μ influence flag Fm _j is reset to “0”, the driving lane situation determination process is terminated, and the process returns to a predetermined main program.
Further, in step S21, performs target brake hydraulic pressure calculation processing shown in FIGS. 4 and 5, firstly, deviation determination flag F _out in step S101, it is determined whether it is set to "1".

The determination result in step S101 is, F when _out = 0, the process proceeds to step S102, the following (5) target braking fluid pressure Ps of the target brake hydraulic pressures Ps _FL and the front right wheel of the front left wheel as shown in the formula _FR is set to the master cylinder hydraulic pressure Pm, and the rear left wheel target brake hydraulic pressure Ps _RL and the rear right wheel target brake hydraulic pressure Ps _RR are calculated from the master cylinder pressure Pm as shown in the following equation (6). After setting the rear wheel master cylinder pressure Pmr in consideration of the front-rear distribution, the target brake fluid pressure calculation process is terminated and the process returns to a predetermined main program.
Ps _FL = Ps _FR = Pm (5)
Ps _RL = Ps _RR = Pmr (6)

On the other hand, when the determination result in step S101 is F _out = 1, the process proceeds to step S103, where it is determined whether or not the target yaw moment Ms is greater than or equal to a preset set value Ms _1. When it is <Ms ₁ , the process proceeds to step S104 and the uneven road flag Fr _j or the low μ road flag Fm _j is affected by disturbance on the travel lane in the travel lane situation determination process of step S3. It is determined whether or not it is set to “1”.

When the determination result in step S104 is not affected by disturbance, the process proceeds to step S105, and the target braking hydraulic pressure differences ΔPs _F and ΔPs _R are calculated based on the following equations (7) and (8). After setting so as to generate a difference only in the braking force of the rear left and right wheels, the process proceeds to step S113 described later.
ΔPs _F = 0 (7)
ΔPs _R = 2 · K _br · | Ms | / T (8)
Here, T is the same tread for the front and rear wheels. _Kbr is a conversion coefficient for converting braking force into braking fluid pressure, and is determined by brake specifications.

If the determination result in step S104 is affected by disturbance, the process proceeds to step S106, and the target braking hydraulic pressure differences ΔPs _F and ΔPs _R are calculated based on the following equations (9) and (10). After setting to zero, the process proceeds to step S113 described later.
ΔPs _F = 0 (9)
ΔPs _R = 0 (10)
On the other hand, when the determination result of step S103 is | Ms | ≧ Ms ₁ , the process proceeds to step S107 to determine whether or not it is affected by disturbance on the traveling lane, similar to step S104. When not affected by the disturbance, the process proceeds to step S108, and the target braking hydraulic pressure differences ΔPs _F and ΔPs _R are calculated based on the following equations (11) and (12), and a difference is generated in the braking force of each wheel. Then, the process proceeds to step S113 described later.

ΔPs _F = 2 · K _bf · (| Ms | −Ms ₁ ) / T (11)
ΔPs _R = 2 · K _br · (| Ms | −Ms ₁ ) / T (12)
Here, K _bf is a conversion coefficient for converting braking force into braking hydraulic pressure, and is determined by brake specifications. In this case, it may be set to ΔPs _F = 2 · K _bf · | Ms | / T by controlling only with the front wheels.
When the determination result in step S107 is affected by disturbance, the process proceeds to step S109 to determine whether or not the departure direction _Dout matches the direction of the affected braking wheel, When the directions do not match, the routine proceeds to step S112, which will be described later, and when the directions match, the routine proceeds to step S110, where it is determined whether only the front braking wheels are affected.

When only the front braking wheel is affected by the disturbance, the process proceeds to step S111, and the target braking hydraulic pressure differences ΔPs _F and ΔPs _R are calculated based on the following formulas (13) and (14) to control the rear left and right wheels. After setting so as to generate only a difference in power, the process proceeds to step S113 described later.
ΔPs _F = 0 (13)
ΔPs _R = 2 · K _br · (| Ms | −Ms ₁ ) / T (14)
On the other hand, when the front and rear braking wheels are affected by disturbance, the process proceeds to step S112, and the target braking hydraulic pressure differences ΔPs _F and ΔPs _R are set to zero based on the following equations (15) and (16), and then described later. The process proceeds to step S113.
ΔPs _F = 0 ……… (15)
ΔPs _R = 0 (16)

In step S113, for the purpose of deceleration, a target braking fluid pressure Pg for generating braking force on both the left and right wheels is calculated based on the following equation (17), and then the process proceeds to step S114 in FIG.
Pg = K _gv · V + K _gx · dX (17)
Here, K _gv and K _gx are conversion coefficients when the braking force set according to the vehicle speed and the lateral displacement amount is converted into the braking hydraulic pressure, respectively. Further, the rear wheel target brake fluid pressure considering the front-rear distribution calculated from the target brake fluid pressure Pg is defined as Pgr.
Next, it is determined whether the braking force is generated on both the left and right wheels for the purpose of decelerating the vehicle based on the determination of the situation on the driving lane and the departure direction, and the master cylinder hydraulic pressure Pm which is a braking operation by the driver is also taken into consideration. Then, the target brake fluid pressure Ps _j for each wheel is calculated.

First, in step S114 of FIG. 5, it is determined whether or not the estimated departure time T _out is equal to or less than a braking determination threshold Tr (Tr <T _S ) set according to the influence of disturbance on the traveling lane. _{When out} > Tr, the process proceeds to step S115, and it is determined whether or not the vehicle is affected by disturbance on the traveling lane as in step S104.

When it is not affected by the disturbance, the routine proceeds to step S116, where it is determined whether or not the target yaw moment Ms is to be generated negatively, that is, leftward. When Ms <0, the following equation (18) is used. The target brake fluid pressure Ps _j for each wheel is calculated. When Ms ≧ 0, the target brake fluid pressure Ps _j for each wheel is calculated based on the following equation (19), and then the target brake fluid pressure calculation process is performed. End and return to a predetermined main program.
Ps _FL = Pm,
Ps _FR = Pm + ΔPs _F ,
Ps _RL = Pmr,
Ps _RR = Pmr + ΔPs _R (18)
Ps _FL = Pm + ΔPs _F ,
Ps _FR = Pm,
Ps _RL = Pmr + ΔPs _R ,
Ps _RR = Pmr ......... (19)

On the other hand, when the determination result of step S115 is affected by disturbance, the process proceeds to step S117, where it is determined whether or not the target yaw moment Ms is equal to or larger than a preset set value Ms _1. When | <Ms ₁ , the process proceeds to step S119 described later, and when | Ms | ≧ Ms ₁ , the process proceeds to step S118.
At step S118, the match with the direction of the impacts and the departure direction D _out braking wheel, and only the front brake wheels determines whether it is affected, when only the direction match and before the braking wheel is affected The process proceeds to step S119.

In step S119, when Ms <0, the target braking fluid pressure Ps _j of each wheel is calculated based on the following equation (20). When Ms ≧ 0, the following equation (21) is used to calculate the target braking fluid pressure of each wheel. After the target braking fluid pressure Ps _j is calculated, the target braking fluid pressure calculation process is terminated, and the process returns to a predetermined main program.
Ps _FL = Pm + Pg / 2
Ps _FR = Pm + ΔPs _F + Pg / 2
Ps _RL = Pmr + Pgr / 2
Ps _RR = Pmr + ΔPs _R + Pgr / 2 (20)
Ps _FL = Pm + ΔPs _F + Pg / 2
Ps _FR = Pm + Pg / 2
Ps _RL = Pmr + ΔPs _R + Pgr / 2
Ps _RR = Pmr + Pgr / 2 (21)

On the other hand, if the determination result in step S118 indicates that the direction mismatch or the front and rear braking wheels are affected, the process proceeds to step S120, and when Ms <0, each wheel is determined based on the following equation (22). The target brake hydraulic pressure Ps _j is calculated. When Ms ≧ 0, the target brake hydraulic pressure Ps _j for each wheel is calculated based on the following equation (23), and then the target brake hydraulic pressure calculation process is terminated. Return to the main program.
Ps _FL = Pm + 2/3 · Pg,
Ps _FR = Pm + ΔPs _F + 2/3 · Pg,
Ps _RL = Pmr + 2/3 · Pg,
Ps _RR = Pmr + ΔPs _R + 2/3 · Pg (22)
Ps _FL = Pm + ΔPs _F + 2/3 · Pg,
Ps _FR = Pm + 2/3 · Pg,
Ps _RL = Pmr + ΔPs _R + 2/3 · Pg,
Ps _RR = Pmr + 2/3 · Pg (23)

When the determination result in step S114 is T _out ≦ Tr, the process proceeds to step S121, where it is determined whether or not the vehicle is affected by disturbance on the traveling lane. The process proceeds to step S122, and after calculating the target braking fluid pressure Ps _j of each wheel based on the above equation (20) or (21) as in step S119, the target braking fluid pressure calculating process is terminated. Return to the predetermined main program.

Determination of the step S121 is, when it is affected by disturbances, the process proceeds to step S123, and determines whether the target yaw moment Ms is set value Ms ₁ or a preset, | Ms | < when a ms _1, the process proceeds to step S125 to be described later, | ms | when a ≧ ms _1, the process proceeds to step S124.
At step S124, the match with the direction of the impacts and the departure direction D _out braking wheel, and only the front brake wheels determines whether it is affected, when only the direction match and before the braking wheel is affected The process proceeds to step S125.

In step S125, as in step S120, the target braking hydraulic pressure Ps _j for each wheel is calculated based on the above formula (22) or (23), and then the target braking hydraulic pressure calculation process is terminated. Return to the program.
If the determination result in step S124 is inconsistent in direction or the front and rear braking wheels are affected, the process proceeds to step S126. When Ms <0, the target of each wheel is calculated based on the following equation (24). The brake fluid pressure Ps _j is calculated. When Ms ≧ 0, the target brake fluid pressure Ps _j for each wheel is calculated based on the following equation (25), and then the target brake fluid pressure calculation process is terminated. Return to the main program.

Ps _FL = Pm + 3/4 · Pg,
Ps _FR = Pm + ΔPs _F + 3/4 · Pg,
Ps _RL = Pmr + 3/4 · Pg,
Ps _RR = Pmr + ΔPs _R + 3/4 · Pg (24)
Ps _FL = Pm + ΔPs _F + 3/4 · Pg,
Ps _FR = Pm + 3/4 · Pg,
Ps _RL = Pmr + ΔPs _R + 3/4 · Pg,
Ps _RR = Pmr + 3/4 · Pg (25)

  In the lane departure prevention control processing of FIGS. 2 to 5, the processing in steps S4 and S5 corresponds to the departure determination means, the processing in steps S31 and S32 corresponds to the unevenness detection means, and the processing in steps S36 and S37 is low μ. Corresponding to the detection means, the processing in step S11 corresponds to the lane change determination means, the processing in steps S15, S17, S19, and S20 corresponds to the target yaw moment calculation means, and the processing in steps S103 to S112 is the yaw control amount calculation. Corresponding to the means, the process of step S113 corresponds to the braking control amount calculating means, and the processes of steps S114 to S126 correspond to the braking / driving force control means.

Accordingly, it is assumed that the host vehicle is traveling straight along the traveling lane without receiving disturbance on the traveling lane. In this case, in the departure prevention control processing of FIG. 2 to FIG. 5, the departure prediction time T _out that satisfies T _out ≧ Ts is calculated in step S4. _out = 0, indicating that there is no tendency to deviate. Accordingly, the process proceeds to step S102 by the determination in step S101 of FIG. 4, and the master cylinder pressures Pm and Pmr corresponding to the driver's braking operation are included in the target braking pressures Ps _{FL to} Ps _RR of the wheels 5FL to 5RR. Each is set, and the running state corresponding to the driver's steering operation is continued.

From this state, it is assumed that the vehicle gradually begins to deviate leftward from the center position of the travel lane due to the driver's sideways look. In this case, since the predicted departure time T _out satisfying T _out <Ts is calculated in step S4, the departure determination flag F _out = 1 in step S7, indicating that there is a tendency toward departure. Since the driver does not intend to change the lane, the lane change flag F _ch = 0 is set in step S11 to step S12, the process proceeds to step S14 through step S13, and the driver is notified of the departure warning. In S15, the target yaw moment Ms in the departure avoidance direction is calculated based on the equation (3). At this time, when the predicted departure time T _out satisfying T _out > Tr is calculated, the departure prevention control is performed only by the yaw moment control so that the target yaw moment Ms is generated in step S116 of FIG. The right target braking fluid pressures Ps _FR and Ps _RR are set to be large based on the equation (18), so that the course in the right direction, which is the departure avoidance direction, is accurately corrected.

On the other hand, when the predicted departure time T _out satisfying T _out ≦ Tr is calculated, it is assumed that the departure prevention control is performed by both the yaw moment control and the deceleration control, based on the target yaw moment Ms and the target brake hydraulic pressure Pg. In step S122, the right target braking fluid pressures Ps _FR and Ps _RR are set to be large on the basis of the equation (20), and the braking force for deceleration control is generated on both the left and right wheels. Correct the course in the right direction.
As described above, since the prevention control is performed by combining the yaw control and the deceleration control according to the departure situation of the vehicle, the wheel to be braked is insufficiently gripped and deviated from the lane due to the insufficient yaw moment in the yaw control. Even in this case, it is possible to prevent deviation accurately by the braking force in the deceleration control.

When the host vehicle MC is traveling straight along the traveling lane, as shown in FIG. 6A, the front right wheel is affected by the unevenness A of the traveling vehicle lane and the vehicle behavior changes, and the vehicle moves to the right. Suppose that there is a tendency to deviate. In this case, the detected stroke amount St _FR serving as St _FR ≧ St _S at a stroke sensor 23, the stroke speed St _FR 'is St _FR' the ≧ Sv _S, uneven effect flag in step S32 in FIG. 3 Fr _FR = 1, indicating that it is affected by unevenness, the departure determination threshold Ts is set to a value Ts1 smaller than the normal departure determination threshold, and the braking determination threshold Tr is a value Tr1 smaller than the normal braking determination threshold. Set to Then, the change amount of the lateral displacement and the estimated time of departure from the distance to the lane T _out is calculated in step S4, by comparing the set departure determination threshold Ts in the step S32 and the estimated time of departure T _out Judgment of lane departure.

In this way, when the vehicle is affected by the unevenness of the traveling lane, the departure determination threshold Ts is set to be smaller than the normal value. For example, the departure determination is made in comparison with the case of the normal lane departure due to the driver's side look. Therefore, it is possible to appropriately perform departure prevention control without causing the driver to feel uncomfortable.
If it is determined in step S5 in FIG. 2 that T _out <Ts, the departure determination flag F _out = 1 is set in step S7, indicating that there is a departure tendency. Since the driver does not intend to change lanes, the lane change flag F _ch = 0 is set from step S11 to step S12, a departure warning is notified to the driver in step S14 via step S13, and the departure avoidance direction is further determined in step S15. The target yaw moment Ms is calculated based on the equation (3).

Since the departure direction is on the right side and the wheel affected by the disturbance is the right front wheel, the departure direction _Dout matches the direction of the affected braking wheel, so the target yaw moment Ms is | Ms | ≧ When Ms ₁ is satisfied, the target braking hydraulic pressure differences ΔPs _F and ΔPs _R for generating a difference in the braking force of the rear left and right wheels are calculated based on the equations (13) and (14) in step S111 of FIG. The Further, when T _out > Tr, the target braking fluid pressure Ps _RL for the left rear wheel is set to be large based on the equation (21) in step S119 of FIG. When the braking force is generated, the course is corrected in the left direction, which is the direction of avoiding the departure.

Further, as shown in FIG. 6 (b), it is assumed that the right front and rear wheels are affected by the unevenness B of the own vehicle travel lane, the vehicle behavior changes, and the vehicle tends to deviate to the right. In this case, it is determined in step S110 of FIG. 4 that the front and rear braking wheels are affected by disturbance on the travel lane, and in step S112, the target braking hydraulic pressure differences ΔPs _F and ΔPs _R are set to (15 ) And (16) are set to zero. Thus, when T _out > Tr, the braking force for deceleration control is generated on both the left and right wheels based on the equation (21) in step S119 of FIG. To prevent lane departure.

As described above, when the target braking fluid pressure difference ΔPs _F and ΔPs _R are calculated in consideration of the affected braking wheel when the vehicle is affected by disturbance on the traveling lane, for example, only the front wheel is affected. By setting the target braking fluid pressure of the rear wheel to a large value by the yaw control and performing the deceleration control, the yaw control is not performed when the front and rear wheels are affected, and the deviation prevention control is performed only by the deceleration control, It is possible to prevent lane departure due to insufficient grip on the wheel to be braked and insufficient yaw moment in yaw control, and to prevent lane departure accurately by increasing braking force in deceleration control. be able to.

In addition, it is assumed that the driver operates the direction instruction switch 22 and the own vehicle MC is about to change the lane to the adjacent lane. In this state, as shown in FIG. 7, when the right front wheel is affected by the unevenness C of the traveling lane and the vehicle behavior changes, and the vehicle tends to deviate to the right side, step S31 to step S32 in FIG. Then, the unevenness influence flag Fr _FR = 1 is set, indicating that the unevenness is affected. Then, in step S11 in FIG. 2, it is determined that the driving vehicle has an intention to change lanes, and in step S16, the lane change flag F _ch = 1 is set and the process proceeds to step S17, where the unevenness influence flag Fr _FR = 1. Therefore, the process proceeds to step S19. Since there was an intention to change the lane before being affected by the disturbance, the process proceeds from step S19 to step S20, and the target yaw moment Ms is calculated based on the equation (4).

As a result, if the lane change is affected by disturbance on the driving lane, and if there is an intention to change the lane before being affected by the disturbance, the degree of return to the vehicle posture before being affected Since the target yaw moment is set, the lane can be changed smoothly and departure prevention control can be performed without causing the driver to feel uncomfortable.
As described above, in the above embodiment, when the vehicle behavior due to the disturbance such as the unevenness of the host vehicle lane or the low friction coefficient is detected and it is determined that the vehicle is affected by the disturbance, the departure determination threshold is changed to determine the departure. Therefore, for example, the departure determination can be suppressed as compared with the case of a normal lane departure due to the driver's aside, and appropriate departure prevention control according to the situation can be performed.

In addition, when it is affected by disturbance on the driving lane, it is determined that the influence continues for a predetermined time, so that it is possible to accurately determine whether the deviation is due to the influence of disturbance, Deviation prevention control can be performed without causing the driver to feel uncomfortable.
Furthermore, when the departure prevention control is performed by combining the yaw control and the deceleration control according to the departure situation of the vehicle, and when it is affected by disturbance on the traveling lane, the target braking hydraulic pressure is determined according to the affected braking wheel. Since the deviation prevention control is performed by calculating the above, it is possible to prevent the departure of the lane due to the insufficiently gripped wheel and insufficient yaw moment in the yaw control.

Also, when affected by disturbances on the driving lane, set the braking force in deceleration control larger than when not affected by disturbances, and when the front and rear wheels are affected by disturbances, Compared with the case where only the front wheels are affected by disturbance, the braking force in the deceleration control is set to be large, so that lane departure can be prevented accurately.
Furthermore, if the lane change is affected by disturbance on the driving lane, it is determined whether the lane change was intended before the influence of the disturbance. If there is an intention, the target yaw moment is set to such an extent that it returns to the vehicle posture before being affected, so the lane can be changed smoothly and departure prevention control that does not make the driver feel uncomfortable. Can do.

In addition, the brake pressures Ps _{FL to} Ps _RR of the wheels 5FL to 5RR are individually controlled to generate the yaw moment Ms in the departure avoidance direction in the own vehicle. It can be corrected accurately.
In the above embodiment, the case where the vehicle speed of the host vehicle is calculated based on each wheel speed detected by the vehicle speed sensor has been described. However, the present invention is not limited to this, and the ABS control or the like is operating. In this case, the estimated vehicle speed estimated in the ABS control may be applied, and if a navigation device is mounted, a value used in the navigation device may be applied.

In the above embodiment, the case where the target yaw moment is calculated based on the equation (3) in step S15 in FIG. 2 is not limited to this. Based on the yaw angle Φ, the lateral displacement X, and the travel lane curvature ρ, the target yaw moment may be calculated based on the following equation.
_{Ms = K a · Φ + K} b · X + K c · ρ ......... (26)
_{Here, K a, K b, K} c is a gain that varies according to each vehicle speed V.

Furthermore, in the above-described embodiment, the case where the target braking hydraulic pressure is calculated based on the equation (17) in step S113 in FIG. 4 is not limited to this, but the vehicle speed V, the host vehicle is not limited thereto. The target braking fluid pressure may be calculated based on the following equation based on the yaw angle Φ and the traveling lane curvature ρ with respect to the traveling lane.
Pg = K _gv · V + K _gf · Φ + K _gr · ρ (27)
Here, K _gf and K _gr are conversion coefficients when the braking force set according to the yaw angle and the traveling lane curvature is converted into the braking hydraulic pressure, respectively.

  Moreover, in the said embodiment, although the case where a driver | operator is not changing lanes and alerting | reporting when it is in a lane departure tendency was demonstrated, it is not limited to this, but alerting | reporting is performed There may be a difference between the timing and the timing at which braking control (yaw control and deceleration control) is performed. Since G is applied to the driver by using the braking control, the braking control itself can have a warning effect.

  Furthermore, in the above-described embodiment, the case where the longitudinal acceleration, the lateral acceleration, and the yaw rate are detected by the navigation system mounted on the vehicle has been described. However, the present invention is not limited to this. Further, a sensor for detecting each of them may be applied, such as detecting a lateral acceleration and installing a yaw rate sensor to detect a yaw rate.

In the above-described embodiment, the configuration in which only the braking pressures Ps _{FL to} Ps _{RR of the} wheels 5FL to 5RR are controlled to generate the yaw moment Ms in the departure avoidance direction in the own vehicle has been described, but the present invention is not limited thereto. If a driving force control device that can control the driving force of each wheel 5FL to 5RR is mounted, the yaw in the departure avoidance direction is controlled by controlling the braking pressure and the driving force of each wheel 5FL to 5RR. A moment Ms may be generated.
Furthermore, although the case where the present invention is applied to a rear wheel drive vehicle has been described in the above embodiment, the present invention can also be applied to a front wheel drive vehicle. In this case, in step S2, among the wheel speeds Vw _FL ~Vw _RR, left and right wheel speeds Vw _RL after a non-driven wheels, may be calculated vehicle speed V of the host vehicle from an average value of Vw _RR.

It is a schematic structure figure showing an embodiment of the present invention. It is a flowchart which shows the lane departure prevention control process performed with the control unit 8 of FIG. 1 in embodiment of this invention. It is a flowchart which shows the driving | running | working lane situation judgment process in the lane departure prevention control process of FIG. 3 is a flowchart showing a target braking fluid pressure calculation process in the lane departure prevention control process of FIG. 2. 3 is a flowchart showing a target braking fluid pressure calculation process in the lane departure prevention control process of FIG. 2. It is a figure explaining operation | movement of embodiment of this invention. It is a figure explaining operation | movement of embodiment of this invention.

Explanation of symbols

6FL to 6RR Wheel cylinder 7 Braking fluid pressure control circuit 8 Control unit 9 Engine 15 Navigation system 16 Master cylinder pressure sensor 17 Steering angle sensor 21FL to 21RR Wheel speed sensor 22 Direction indicator switch 23FL to 23RR Stroke sensor 24 Alarm device

Claims (9)

In a lane departure prevention apparatus for controlling the host vehicle so as to avoid a departure from the traveling lane of the host vehicle,
A traveling state detecting unit for detecting a traveling state of the host vehicle, and a disturbance influence detecting unit for detecting an influence of a disturbance on a road surface on the traveling lane of each wheel based on the traveling state detected by the traveling state detecting unit; A departure determining means for determining that the host vehicle tends to deviate from the traveling lane based on the traveling state detected by the traveling state detecting means and the disturbance influence of each wheel detected by the disturbance influence detecting means; When the departure determining means determines that the host vehicle tends to depart from the traveling lane, the traveling state detected by the traveling state detecting means and the disturbance influence of each wheel detected by the disturbance influence detecting means and a departure prevention control means for controlling the vehicle in a direction to avoid the deviation according to,
The departure prevention control means is detected by the travel state detected by the travel state detection means and the disturbance influence detection means when the departure determination detection means detects that the host vehicle is deviating from the travel lane. Yaw control amount calculation that calculates the first braking / driving force control amount of each wheel so that the yaw moment is generated in a direction that avoids deviation from the traveling lane of the host vehicle according to the disturbance influence of each wheel And a second state of each wheel so that a braking force is generated in the own vehicle according to the traveling state detected by the traveling state detecting unit and the disturbance influence of each wheel detected by the disturbance influence detecting unit. A braking control amount calculating means for calculating a braking / driving force control amount, and a braking control amount of each wheel according to the first and second braking / driving force control amounts calculated by the yaw control amount calculating means and the braking control amount calculating means. Braking / driving force control hand to control driving force It equipped with a door,
The braking control amount calculating means is configured such that when the disturbance influence detecting means detects the disturbance influence of the front and rear wheels, the braking force is generated in the host vehicle larger than when the disturbance influence of only the front wheels is detected. A lane departure prevention apparatus characterized in that a second braking / driving force control amount for each wheel is calculated . In a lane departure prevention apparatus for controlling the host vehicle so as to avoid a departure from the traveling lane of the host vehicle,
A traveling state detecting unit for detecting a traveling state of the host vehicle, and a disturbance influence detecting unit for detecting an influence of a disturbance on a road surface on the traveling lane of each wheel based on the traveling state detected by the traveling state detecting unit; A departure determining means for determining that the host vehicle tends to deviate from the traveling lane based on the traveling state detected by the traveling state detecting means and the disturbance influence of each wheel detected by the disturbance influence detecting means; When the departure determining means determines that the host vehicle tends to depart from the traveling lane, the traveling state detected by the traveling state detecting means and the disturbance influence of each wheel detected by the disturbance influence detecting means And a departure prevention control means for controlling the host vehicle in a direction to avoid the departure according to
The departure prevention control means is detected by the travel state detected by the travel state detection means and the disturbance influence detection means when the departure determination detection means detects that the host vehicle is deviating from the travel lane. Yaw control amount calculation that calculates the first braking / driving force control amount of each wheel so that the yaw moment is generated in a direction that avoids deviation from the traveling lane of the host vehicle according to the disturbance influence of each wheel And a second state of each wheel so that a braking force is generated in the own vehicle according to the traveling state detected by the traveling state detecting unit and the disturbance influence of each wheel detected by the disturbance influence detecting unit. A braking control amount calculating means for calculating a braking / driving force control amount, and a braking control amount of each wheel according to the first and second braking / driving force control amounts calculated by the yaw control amount calculating means and the braking control amount calculating means. Braking / driving force control hand to control driving force It equipped with a door,
The yaw control amount calculating means controls the first braking / driving force control of each wheel so as to perform yaw control on the rear wheel which is a non-disturbance influence wheel when the disturbance influence detection means detects the disturbance influence of only the front wheel. car beam deviation preventing system you and calculates the amount.   3. The disturbance influence detecting means, after detecting the disturbance influence of each wheel based on the running state detected by the running state detecting means, determines that the disturbance influence is occurring for a predetermined time. The lane departure prevention device according to claim 1. The traveling state detecting means detects the vertical stroke amount of each wheel of the host vehicle, and the disturbance influence detecting means is based on the stroke amount detected by the traveling state detecting means, and the unevenness of each vehicle running lane. lane departure prevention apparatus according to any one of claims 1 to 3, characterized in that it comprises a concave-convex detecting means for detecting the disturbance influence. The traveling state detecting means detects the slip ratio of the wheels of the own vehicle, and the disturbance influence detecting means is based on the slip ratio detected by the traveling state detecting means, and each wheel by the low friction coefficient road of the own vehicle traveling lane. lane departure prevention apparatus according to any one of claims 1 to 4, characterized in that it comprises a low μ detecting means for detecting a disturbance effect of. The braking control amount calculating means detects the second braking force of each wheel such that a greater braking force is generated in the host vehicle when the disturbance influence detecting means detects the disturbance influence of the wheels than when no disturbance influence is detected. lane departure prevention apparatus according to any one of claims 1 to 5 is characterized by calculating the longitudinal force control amount.   The travel state detection means detects an angle formed by the travel lane and the longitudinal axis of the host vehicle, a lateral displacement of the host vehicle with respect to the travel lane, and a curvature of the travel lane of the host vehicle. There is a target yaw moment calculating means for calculating a target yaw moment to be generated in the vehicle according to the running state detected by the running state detecting means, and each wheel is applied to each wheel according to the target yaw moment calculated by the target yaw moment calculating means. The lane departure prevention apparatus according to any one of claims 1 to 6, wherein a first braking / driving force control amount to be generated is calculated.   Lane change determining means for determining the driver's intention to change lane, the target yaw moment calculating means is determined that the lane change determining means has an intention to change lane during the influence of the disturbance, and before the influence of the disturbance 8. The lane departure prevention apparatus according to claim 7, wherein when it is determined that there is an intention to change lanes, the target yaw moment is calculated so as to return the vehicle to a posture before the influence of disturbance.   In a lane departure prevention apparatus for controlling the host vehicle so as to avoid a departure from the traveling lane of the host vehicle,
  A traveling state detecting unit for detecting a traveling state of the host vehicle, and a disturbance influence detecting unit for detecting an influence of a disturbance on a road surface on the traveling lane of each wheel based on the traveling state detected by the traveling state detecting unit; A departure determining means for determining that the host vehicle tends to deviate from the traveling lane based on the traveling state detected by the traveling state detecting means and the disturbance influence of each wheel detected by the disturbance influence detecting means; When the departure determining means determines that the host vehicle tends to depart from the traveling lane, the traveling state detected by the traveling state detecting means and the disturbance influence of each wheel detected by the disturbance influence detecting means And a departure prevention control means for controlling the host vehicle in a direction to avoid the departure according to the vehicle, and a lane change determination means for determining the driver's intention to change the lane,
  The departure prevention control means is detected by the travel state detected by the travel state detection means and the disturbance influence detection means when the departure determination detection means detects that the host vehicle is deviating from the travel lane. Yaw control amount calculation that calculates the first braking / driving force control amount of each wheel so that the yaw moment is generated in a direction that avoids deviation from the traveling lane of the host vehicle according to the disturbance influence of each wheel And a second state of each wheel so that a braking force is generated in the own vehicle according to the traveling state detected by the traveling state detecting unit and the disturbance influence of each wheel detected by the disturbance influence detecting unit. A braking control amount calculating means for calculating a braking / driving force control amount, and a braking control amount of each wheel according to the first and second braking / driving force control amounts calculated by the yaw control amount calculating means and the braking control amount calculating means. Braking / driving force control hand to control driving force It equipped with a door,
  The travel state detection means detects an angle formed by the travel lane and the longitudinal axis of the host vehicle, a lateral displacement of the host vehicle with respect to the travel lane, and a curvature of the travel lane of the host vehicle. There is a target yaw moment calculating means for calculating a target yaw moment to be generated in the vehicle according to the running state detected by the running state detecting means, and each wheel is applied to each wheel according to the target yaw moment calculated by the target yaw moment calculating means. Calculating a first braking / driving force control amount to be generated;
  The target yaw moment calculating means disturbs the vehicle when it is determined by the lane change determining means that there is an intention to change lanes during the influence of disturbance, and when it is determined that there is an intention to change lanes before the influence of disturbance. A lane departure prevention apparatus characterized in that a target yaw moment is calculated so as to return to a posture before the influence.

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