JP4007319B2 - Lane change judgment device and lane departure prevention device equipped with the same - Google Patents

Description

  The present invention relates to a lane change determination apparatus that determines a driver's intentional lane change, and a lane departure prevention apparatus including the lane change determination apparatus.

Conventionally, when a vehicle is about to deviate from the driving lane, in a lane keeping support system that determines whether it is an intentional lane change by the driver and prevents the lane departure, Even if the vehicle is not operated, for example, if both the steering angle and the amount of change thereof exceed a predetermined value, it is determined that the driver has intentionally changed the lane (see Patent Document 1).
JP 2003-154910 A

However, when the driver changes lanes without operating the direction indicator, the steering operation is very diverse, and constantly changes depending on the situation such as the driving environment and traffic conditions. Therefore, as in the conventional example described in Patent Document 1, when there is no operation of the direction indicating device, it is determined whether or not the driver intentionally changes the lane based on the steering operation state. However, only a rough judgment result can be obtained.
Therefore, the present invention has been made paying attention to the above points, and provides a lane change determination device that can more accurately determine an intentional lane change by a driver even when the direction indicator is not operated. The challenge is to do.

In order to solve the above-described problems, the lane change determination device according to the present invention reduces the forward view according to at least one of the driving scenes of the vehicle , that is, the surrounding weather condition, the brightness, and the road surface condition. It is determined that the driver is less likely to change the lane without operating the direction indicator, and a predetermined condition for determining that the driver is changing the lane is determined according to the determination result. It is characterized by changing.

According to the lane change determination device of the present invention, the direction of the driver decreases as the forward visibility decreases according to at least one driving environment of the driving scene of the vehicle , that is, the surrounding weather condition, brightness, and road surface condition. By determining that the possibility of changing the lane is low without operating the indicator, and changing the predetermined condition for determining that the driver is changing the lane according to the determination result, at least The intentional lane change by the driver can be more accurately determined according to the driving scene including the driving environment.

Hereinafter, the best mode for carrying out the present invention will be described with reference to the drawings.
FIG. 1 is a schematic configuration diagram showing an embodiment of the present invention. In the figure, 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 according to the amount of depression of the brake pedal 1 by the driver is Supplied to the wheel cylinders 6FL-6RR of the wheels 5FL-5RR.

  A brake fluid pressure control circuit 7 used for anti-skid control (ABS), traction control (TCS), stability control (VDC), etc. is interposed between the master cylinder 3 and each wheel cylinder 6FL-6RR. ing. The brake fluid pressure control circuit 7 is configured to be able to individually control the brake fluid pressures of the wheel cylinders 6FL to 6RR regardless of the driver's brake operation by an actuator such as a proportional solenoid valve. The braking fluid pressure circuit 7 controls the braking fluid pressure in accordance with a braking fluid pressure control command output from the control unit 8.

  The drive torque controller 9 can control the drive torque of the rear wheels 5RL and 5RR by controlling the fuel injection and ignition timing of the engine 10, the gear ratio of the automatic transmission 11, and the throttle opening of the throttle valve 12. It is configured as follows. The drive torque controller 9 controls the drive torque according to the drive torque control command output from the control unit 8.

  In addition, a camera 13 that captures the front of the vehicle is provided above the room mirror, and the captured image is input to the image processing device 14. The image processing device 14 recognizes a lane marker such as a white line from an image in front of the vehicle and detects a travel lane, and also detects the vehicle's yaw angle φ with respect to the travel lane, a lateral displacement X from the center of the travel lane, The lane curvature β is calculated and output to the control unit 8. At this time, if the white line cannot be clearly recognized due to fading of white line or snowfall, the yaw angle φ, lateral displacement X, and curvature β are set to 0 and output. However, when the white line cannot be recognized temporarily due to noise or an obstacle, the previous value is held for each value.

  Further, scanning laser radar devices 15F and 15R are disposed at the front end portion and the rear end portion of the vehicle body. The laser radar devices 15F and 15R emit infrared laser light forward and backward while changing the angle within a predetermined angle range, and the time and scanning angle until the infrared laser is reflected by an object and received. Based on the above, the vertical distance Lx and the horizontal distance Ly with respect to the front and rear vehicles are calculated and output to the control unit 8. Note that not only a laser radar device but also a millimeter wave radar that detects a distance from a frequency difference due to the Doppler effect may be used.

Further, an optical or capacitive raindrop detection sensor 16 detects a waterfall Fa by detecting a waterdrop on the front window shield glass, and a light switch 17 detects ON / OFF of the headlamp. These detection signals are also input to the control unit 8.
Further, the master cylinder pressure sensor 18 detects a master cylinder pressure Pm that is an output pressure of the master cylinder 3, an accelerator sensor 19 detects an accelerator opening Acc that is a depression amount of an accelerator pedal, and a steering angle sensor 20 , The steering angle δ of the steering wheel 21 is detected, the wheel rotation sensors 22FL to 22RR detect the rotational speeds Vw _{FL to} Vw _RR of each wheel, and the direction indicator switch 23 detects the operation state of a direction indicator (not shown). These detection signals are also input to the control unit 8.

When the above-mentioned various data have left and right directions, the left direction is a positive value and the right direction is a negative value. That is, the yaw angle φ and the steering angle δ are positive values when turning left and negative values when turning right, and the lateral displacement X is positive when it is shifted to the left from the center of the driving lane and is shifted to the right. The negative value is when
In the vicinity of the driver's seat, an alarm device 24 for notifying the driver when the vehicle tends to deviate is installed, and a sound and a buzzer sound are generated according to an alarm signal output from the control unit 8. To do.

Next, the lane departure prevention control process executed by the control unit 8 will be described with reference to the flowcharts of FIGS.
First, in step S1, various data are read. Specifically, yaw angle φ, lateral displacement X, curvature β, distances Lx and Ly with front and rear vehicles, rainfall Fa, headlamp operating state, master cylinder pressure Pm, accelerator opening Acc, steering angle δ, The wheel speeds Vw _{FL to} Vw _RR are the operating states of the direction indicator.
In the subsequent step S2, the average wheel speed of the front wheels that are non-driven wheels is calculated as the vehicle speed V as shown in the following equation (1).
V = (Vw _FL + Vw _FR ) / 2 (1)

In subsequent step S3, an estimated deviation value XS from the traveling lane is calculated according to the following equation (2). Here, Tt is the vehicle head time used for calculating the forward gaze distance. That is, in this embodiment, the lateral displacement estimated value from the center of the lane after the vehicle head time Tt is calculated as the deviation estimated value XS. Incidentally, the value obtained by multiplying the vehicle head time Tt by the vehicle speed V is the forward gaze distance.
XS = Tt × V × (φ + Tt × V × β) + X (2)
In the subsequent step S4, an environment mode for quantifying the traveling environment is set based on the headlamp ON / OFF and the rainfall amount Fa with reference to a table as shown in FIG. Here, the table in FIG. 4 divides the environmental mode into stages 1 to 8, the surroundings become dark, the headlamps are turned on, the weather condition changes to rainy weather, and the visibility of the front view is reduced, It is set so that the numerical value of the environmental mode becomes lower as the driving environment gets worse.

  In the subsequent step S5, first, a map as shown in FIG. 5A is referenced, and the degree of separation from the front and rear vehicles is quantified based on the vertical distance Lx and the horizontal distance Ly. Here, the map in FIG. 5A divides the degree of separation from the front and rear vehicles into stages 1 to 4, and is set so that the numerical value increases as the distance from the front and rear vehicles increases. At this time, if there is no front vehicle or rear vehicle, the degree of separation is set to 5. On the other hand, when there are a plurality of front vehicles or rear vehicles, the nearest vehicle is selected (the driving lane may be different), and the degree of separation from the vehicle is set.

Then, referring to a table as shown in FIG. 5B, a road traffic situation mode for quantifying the road traffic situation is set based on the degree of separation from the preceding vehicle and the rear vehicle. Here, the table of FIG. 5B is set so that the road traffic situation mode is divided into stages 1 to 25, and the numerical value of the road traffic situation mode increases as the degree of separation from the preceding and following vehicles increases. .
In the subsequent step S6, first, as shown in the following equation (3), a steering angle δn necessary for the vehicle to travel along the traveling lane is calculated. Here, Ks and A are constants determined from vehicle specifications.
δn = Ks × (1 + A × V ² ) × φ (3)

Then, as shown in the following equation (4), a steering angle deviation Δδ between the above δn and the actual steering angle δ is calculated. When the steering angle deviation Δδ is a positive value, it indicates that the vehicle is steered toward the left side of the lane, and when the value is a negative value, it indicates that the vehicle is steered toward the right side of the lane.
Δδ = δ−δn (4)
Then, referring to a map as shown in FIG. 6, a lateral movement state mode for quantifying the lateral movement state of the host vehicle with respect to the traveling lane is set based on the steering angle deviation Δδn and the lateral displacement X. . Here, in the map of FIG. 6, the value of the lateral movement state mode is in the range of 1 to 4 as the travel position is shifted to the left (or right) from the center of the lane and steered toward the left (or right) lane. It is set to be large. On the other hand, the value of the lateral movement state mode is set to be larger in the range of 5 to 8 as the travel position is shifted to the left (or right) from the center of the lane and steered toward the right (or left) lane. ing.

  In subsequent step S7, the table as shown in FIG. 7 is referred to, and the possibility that the driver changes the lane without operating the direction indicator is changed to the environmental mode, the road traffic condition mode, and the lateral movement state mode. Based on the determination, a determination flag Fj is set. The determination flag Fj is set to any one of 1 to 3, and the higher the value, the higher the possibility that the driver will change the lane without operating the direction indicator. Here, the table of FIG. 7 changes the lane without operating the direction indicator in any driving scene (driving environment, road traffic situation, lateral movement state) or the like through experiments and research. Analyze and create. Of course, the driving situation is usually memorized by the driver, and the table in Fig. 7 is corrected as needed based on the stored data to learn the operating characteristics of the driver. You may let them.

  For example, the driver tends to be more cautious as the driving environment deteriorates due to a decrease in the visibility of the front view, and the driver is likely to operate the direction indicator correctly. That is, when the visibility of the front view is good, it is considered that the driver is more likely to change the lane without operating the direction indicator than when the visibility is low. The higher the mode value, the higher the determination flag Fj is set.

In addition, it is considered that the driver is more likely to change lanes without operating the direction indicator when there is no surrounding vehicle or when the degree of separation from the surrounding vehicle is high. The higher the value, the higher the determination flag Fj is set.
Also, when the driving position is greatly deviated from the center of the lane and is steered greatly toward the outside of the lane, that is, when the vehicle is already straddling the white line and the transition to the adjacent lane is about to be completed, Since it is considered that the person is unlikely to operate the direction indicator, the value of the determination flag Fj is generally set to be higher as the value of the lateral movement state mode is higher in the range of 1 to 4.

In a succeeding step S8, it is determined whether or not the direction indicating switch 23 is ON. Here, when the direction indicating switch 23 is OFF, the process proceeds to step S12 described later, and when the direction indicating switch 23 is ON, the process proceeds to step S9.
In step S9, it is determined whether or not the direction indicated by the direction indicator matches the deviation estimation direction (the sign of the deviation estimation value XS). Here, when the direction indicated by the direction indicator coincides with the estimated departure direction, it is determined that the lane change is intentional, the process proceeds to step S10, and the lane change flag Fc is set to “1”. On the other hand, when the indicated direction of the direction indicator does not match the estimated departure direction, it is determined that the lane change is not intentional, and the process proceeds to step S11 to reset the lane change flag Fc to “0”.

In step S12, it is determined whether or not it is immediately after the direction indicating switch 23 is switched from ON to OFF. Here, when the direction indicating switch 23 is maintained OFF, the process proceeds to step S15 described later, and when immediately after the direction indicating switch 23 is switched from ON to OFF, the process proceeds to step S13.
In step S13, it is determined whether or not a predetermined time (for example, about 4 seconds) has elapsed since the direction indicator was switched from ON to OFF. If the predetermined time has not elapsed, the process proceeds to step S10. On the other hand, when a predetermined time has elapsed since the direction indicator was switched from ON to OFF, the process proceeds to step S14 and the lane change flag Fc is reset to “0”. Here, even if the direction indicator is switched from ON to OFF, the state in which the lane change flag Fc is set to “1” is maintained for a predetermined time only during the lane change by the driver or by the driving operation. This is because the operation of the direction indicator may be canceled.

  In step S15, referring to the maps of FIGS. 8 and 9, the steering angle threshold value δs for determining that the driver is changing the lane without operating the direction indicator, and the steering angle change amount threshold value. dδs is set according to the determination flag Fj. Here, according to the map of FIG. 8, the steering angle threshold δs is set to δ1 when the determination flag Fj = 1, and is set to δ2 smaller than δ1 when the determination flag Fj = 2. When determination flag Fj = 3, δ3 smaller than δ2 is set. Further, according to the map of FIG. 9, the steering angle change amount threshold value dδs is set to dδ1 when the determination flag Fj = 1, and is set to dδ2 smaller than dδ1 when the determination flag Fj = 2. When the determination flag Fj = 3, dδ3 smaller than dδ2 is set. That is, the thresholds δs and dδs are set to be smaller as the driver is more likely to change the lane without operating the direction indicator (the higher the value of the determination flag Fj).

  In the subsequent step S16, it is determined whether or not the steering angle δ is greater than or equal to the threshold value δs and the steering angle change amount dδ is greater than or equal to the threshold value dδs. Here, when δ ≧ δs and dδ ≧ dδs, it is determined that the lane change is intentional by the driver, the process proceeds to step S17, and the lane change determination flag Fc is set to “1”. On the other hand, when δ <δs or dδ <dδs, it is determined that there is no intentional lane change by the driver, the process proceeds to step S18, and the lane change flag Fc is reset to “0”.

When the lane change flag Fc is thus set, the process proceeds to step S19 in FIG. 3, and it is determined whether or not the lane change flag Fc is reset to “0”. When the determination result is Fc = 0, the process proceeds to step S23 described later, and when Fc = 1, the process proceeds to step S20.
In step S20, as shown in the following equation (5), sets the front wheel target brake fluid pressure Ps _FL and Ps _FR to the master cylinder pressure Pm, the target brake hydraulic pressures Ps _RL and Ps _RR master cylinder pressure of the rear wheel The rear wheel master cylinder pressure Pmr is set in consideration of the front / rear distribution calculated from Pm.
Ps _FL = Ps _FR = Pm
Ps _RL = Ps _RR = Pmr (5)

In the subsequent step S21, the target drive torque Trq is calculated as shown in the following equation (6). Here, f (Acc) is a function for calculating the target drive torque in accordance with the accelerator opening Acc.
Trq = f (Acc) (6)
In the subsequent step S22, a braking fluid pressure control command corresponding to the target braking fluid pressures Ps _{FL to} Ps _RR is output to the braking fluid pressure control circuit 7 and a driving torque control command corresponding to the target driving torque Trq is output to the driving torque controller 9. To return to a predetermined main program.

  On the other hand, in step S23, it is determined whether or not the absolute value of the deviation estimated value XS is greater than or equal to the warning threshold value Xw. This alarm threshold value Xw is set to a value (Xc−Xm) obtained by subtracting a predetermined value Xm from the lateral displacement limit value Xc at which departure prevention control is started in order to generate an alarm prior to the start of departure prevention control. Yes. When this determination result is | XS | ≧ Xw, it is determined that a departure warning is necessary, and the process proceeds to step S24. After outputting an alarm signal to the alarm device 24, the process proceeds to step S28 described later. On the other hand, when the determination result is | XS | <Xw, the process proceeds to step S25.

In step S25, it is determined whether the alarm device 24 is operating. When the alarm device 24 is stopped, the process proceeds to step S28, and when the alarm device 24 is in operation, the process proceeds to step S26.
In step S26, it is determined whether or not the absolute value of the deviation estimated value XS is smaller than a value obtained by subtracting the predetermined value Xh from the alarm threshold value Xw (Xw−Xh). Here, the predetermined value Xh is a hysteresis for avoiding the hunting of the departure alarm. When this determination result is | XS | <Xw−Xh, it is determined that there is no need for a departure alarm, the process proceeds to step S27, the alarm signal output to the alarm device 24 is stopped, and then the process proceeds to step S28. To do. On the other hand, when the determination result is | XS | ≧ Xw−Xh, there is a possibility that the estimated deviation value XS has temporarily decreased, and the process proceeds to step S24.

In step S28, it is determined whether or not the absolute value of the estimated deviation value XS is equal to or greater than the lateral displacement limit value Xc (for example, about 0.8 m). The lateral displacement limit value Xc may be a constant or may be changed according to the travel lane width L or the vehicle width Lc as shown in the following equation (7). Incidentally, the lane width L may be calculated from the image data or may be obtained from the road map information of the navigation system. Furthermore, if the information can be acquired from the infrastructure, it may be used.
Xc = min [(L−Lc) / 2, 0.8] (7)

When this determination result is | XS | <Xc, it is determined that the vehicle does not tend to deviate, and the process proceeds to step S20. On the other hand, when the determination result is | XS | ≧ Xc, the vehicle tends to deviate. If it is determined that there is, the process proceeds to step S29.
In step S29, the absolute value | XS (n-1) -XS (n) | obtained by subtracting the current deviation estimated value XS (n) from the previous deviation estimated value XS (n-1) is discontinuous. It is determined whether or not it is equal to or greater than a threshold Ls to be determined. When this determination result is | XS (n−1) −XS (n) | ≧ Ls, it is determined that the departure determination is unstable and the process proceeds to step S20. On the other hand, the determination result is | XS (n− 1) When -XS (n) | <Ls, the process proceeds to step S30.

In step S30, as shown in the following equation (8), the target yaw moment Ms in the departure avoidance direction generated in the host vehicle is calculated according to the departure estimated value XS. Here, K1 is a constant determined by vehicle specifications. K2 is a gain that varies according to the vehicle speed, and is calculated with reference to a control map as shown in FIG. The control map of FIG. 10 is set so that the gain K2 decreases stepwise as the vehicle speed V increases.
Ms = −K1 × K2 × (XS−Xc) (8)

In a succeeding step S31, it is determined whether or not the absolute value of the target yaw moment Ms is smaller than a predetermined value Ms1. When this determination result is | Ms | <Ms1, the process proceeds to step S32, and the left and right wheel braking fluid pressure difference ΔPs _{F of} the front wheel and the left and right wheel braking fluid pressure difference ΔPs _{R of the} rear wheel are calculated according to the following equation (9). . Here, T is the tread that is the same for the front and rear wheels, and K _BR is a conversion coefficient that converts the braking force of the rear wheels into the braking fluid pressure, and is determined by the brake specifications.
ΔPs _F = 0
ΔPs _R = 2 × K _BR × | Ms | / T (9)

On the other hand, when the determination result is | Ms | ≧ Ms1, the process proceeds to step S33, and the left and right wheel braking fluid pressure difference ΔPs _{F of} the front wheel and the left and right wheel braking fluid pressure difference ΔPs _{R of the} rear wheel are calculated according to the following equation (10). To do. K _BF is a conversion coefficient for converting the braking force of the front wheels into the braking fluid pressure.
ΔPs _F = 2 × K _BF × (| Ms | −Ms1) / T
ΔPs _R = 2 × K _BR × Ms1 / T (10)

When the left and right wheel braking fluid pressure differences ΔPs _F and ΔPs _R are thus calculated, the process proceeds to step S34, and whether or not the departure avoidance direction is right (the departure direction is left), that is, whether or not the target yaw moment Ms is a negative value. Determine. Here, when it is determined that the departure avoidance direction is right (the departure direction is left), that is, Ms <0, the process proceeds to step S35, and as shown in the following equation (11), the target braking fluid of the front left wheel The pressure Ps _FL is set to the master cylinder pressure Pm, the front right wheel target braking fluid pressure Ps _{FR is set} to the master cylinder pressure Pm plus the left and right wheel braking fluid pressure difference ΔPs _F , and the rear left wheel target braking fluid pressure is set. Ps _{RL is set} to the rear wheel master cylinder pressure Pmr, and the rear right wheel target brake fluid pressure Ps _RR is set to a value obtained by adding the left and right wheel brake fluid pressure difference ΔPs _R to the rear wheel master cylinder pressure Pmr.
Ps _FL = Pm
Ps _FR = Pm + ΔPs _F
Ps _RL = Pmr
Ps _RR = Pmr + ΔPs _R (11)

On the other hand, the departure avoidance direction is the left (deviation direction is right), i.e. goes to step S36 when it is Ms ≧ 0, as shown in the following equation (12), before the master target brake fluid pressure Ps _FL of the left wheel The cylinder pressure Pm is set to a value obtained by adding the left and right wheel brake fluid pressure difference ΔPs _F , the front right wheel target brake fluid pressure Ps _FR is set to the master cylinder pressure Pm, and the rear left wheel target brake fluid pressure Ps _{RL is set} to the rear wheel. The left master wheel pressure Pmr is set to a value obtained by adding the left and right wheel brake fluid pressure difference ΔPs _R , and the rear right wheel target brake fluid pressure Ps _RR is set to the rear wheel master cylinder pressure Pmr.
Ps _FL = Pm + ΔPs _F
Ps _FR = Pm
Ps _RL = Pmr + ΔPs _R
Ps _RR = Pmr (12)

When the target braking fluid pressures Ps _{FL to} Ps _RR are thus calculated, the process proceeds to step S37, and after calculating the target drive torque Trq according to the following equation (13), the process proceeds to step S22. Here, Ps is a value obtained by adding the left and right wheel braking fluid pressure differences ΔPs _F and ΔPs _R generated by the departure prevention control (= ΔPs _F + ΔPs _R ), and g (Ps) calculates the braking torque expected to be generated. It is a function.
Trq = f (Acc) −g (Ps) (13)

  From the above, the processing of steps S1 to S18 corresponds to the lane change determination device, of which the processing of steps S4 to S6 corresponds to the traveling scene detection means, the processing of step S7 corresponds to the determination means, The process corresponds to the changing means. Further, the process of step S28 corresponds to the departure determination means, and the processes of steps S30 to S36 and the brake fluid pressure control circuit 7 correspond to the departure prevention means.

Next, the operation and effects of the one embodiment will be described.
Now, assume that the driver operates the direction indicator and changes the lane in the indicated direction. At this time, the direction indicating switch 23 is turned ON, and the indicated direction matches the estimated departure direction (both determinations in steps S8 and S9 are “Yes”), so it is easy to determine the intentional lane change by the driver. The lane change flag Fc is set to “1”.
As a result, the departure warning is not notified, and the target brake fluid pressures Ps _{FL to} Ps _{RR of the} wheels are set to the master cylinder pressures Pm and Pmr according to the driver's brake operation, respectively (step S20). A person can smoothly change lanes.

  On the other hand, it is assumed that the driver changes lanes without operating the direction indicator. At this time, whether the steering angle δ exceeds the threshold value δs and the steering angle change amount dδ exceeds the threshold value dδs determines whether it is an intentional lane change or a lane departure (step). S16-S18). However, when the driver changes lanes without operating the direction indicator, the steering operation is very diverse and constantly changes depending on the driving scene.

Therefore, in this embodiment, the driver determines the possibility of changing the lane without operating the direction indicator according to the driving scene, and determines that the driver is changing the lane according to the determination result. The threshold values δs and dδs are changed.
First, in order to grasp the driving scene, according to the environmental mode according to the surrounding weather condition and brightness, the road traffic situation mode according to the degree of separation from the surrounding vehicle, the steering angle deviation Δδn and the lateral displacement X The horizontal movement state mode is set (steps S4 to S6). Next, the determination flag Fj is set by determining the possibility that the driver changes the lane without operating the direction indicator according to the value of each mode (step S7). In this manner, the traveling scene of the vehicle can be grasped by detecting the traveling environment, the road traffic situation, and the lateral movement state of the vehicle.

  The threshold values δs and dδs are reduced as the value of the determination flag Fj is higher, that is, as the driver is more likely to change lanes without operating the direction indicator. Thereby, for example, the degree of separation from surrounding vehicles is high, or the transition to the adjacent lane is about to be completed, and in a driving scene where the driver is likely to change lanes without operating the direction indicator, Even if the direction indicator is not operated, it can be easily determined that the lane change is intentional.

  Conversely, the thresholds δs and dδs are increased as the determination flag Fj is lower, that is, as the driver is more likely to operate the direction indicator accurately. As a result, for example, in a driving scene where the visibility of the front field of view decreases and the driving environment deteriorates, or the degree of separation from the surrounding vehicle is low, and the driver is highly likely to operate the direction indicator accurately. This makes it difficult to determine that the driver is changing lanes. In other words, if there is no operation of the direction indicator in spite of the fact that the driver is highly likely to operate the direction indicator accurately, it is intentional even if the vehicle tends to deviate. Since there is a high possibility of an unconscious lane departure rather than a lane change, it can be easily determined that the lane change is not an intentional lane change.

Therefore, the threshold for determining that the driver is changing the lane without operating the direction indicator from the traveling scene of the vehicle and determining that the driver is changing the lane according to the determination result. By changing δs and dδs, it is possible to more accurately determine the intentional lane change by the driver according to various driving situations such as the driving environment, the road traffic situation, and the lateral movement state.
Thus, when it is determined that the lane change is intentional by the driver even if the direction indicator is not operated, the lane change flag Fc is set to “1”. Lane change can be performed smoothly.

  When it is determined that the lane change is not an intentional lane change, the lane change flag Fc is reset to “0” to determine whether or not the vehicle tends to deviate based on the estimated departure value XS. At this time, when the vehicle is traveling along the traveling lane and the deviation estimated value XS is less than the lateral displacement limit value Xc (determination in Step S28 is “No”), the target braking fluid pressures PsFL to PsRR of the respective wheels. Are set to the master cylinder pressures Pm and Pmr according to the driver's braking operation, respectively, so that the normal traveling state according to the driver's steering operation, accelerator operation, and brake operation is maintained.

From this state, when the vehicle gradually begins to deviate from the center position of the traveling lane and the absolute value of the deviated estimated value XS is equal to or greater than the warning threshold value Xw (determination in step S23 is “Yes”), there is a possibility of deviating from the lane. It is determined that there is a sound, and a sound and a buzzer sound for notifying the fact are notified to the driver (step S24).
By this departure warning, the driver can recognize that the vehicle is in a departure tendency, and can prompt the steering operation in the departure avoidance direction. The driver performs corrective steering in accordance with this, and the departure estimated value XS is If it becomes less than a predetermined value (Xw−Xh) smaller than the alarm threshold value Xw, the departure alarm is stopped.

On the other hand, when the lateral displacement speed of the vehicle is fast or the driver's correction steering is delayed and the estimated deviation value XS further exceeds the lateral displacement limit value Xc (determination in step S28 is "Yes"), the host vehicle Is determined to depart from the lane. Accordingly, the target yaw moment Ms in the deviation avoidance direction necessary for correcting the vehicle course is calculated based on the deviation estimated value XS (step S30), and the left and right wheels necessary for generating the target yaw moment Ms in the vehicle are calculated. A brake fluid pressure difference ΔPs _F and ΔPs _R is calculated. Specifically, when the target yaw moment Ms is smaller than the predetermined value Ms1, the brake fluid pressure difference between the left and right wheels is generated only on the rear wheel side, and when the target yaw moment Ms is greater than or equal to the predetermined value Ms1, The brake fluid pressure differences ΔPs _F and ΔPs _R between the left and right wheels are calculated so that the wheel brake fluid pressure difference occurs on both the front wheel side and the rear wheel side (steps S31 to S33).

Next, in order to generate the brake fluid pressure differences ΔPs _F and ΔPs _R between the left and right wheels on the front and rear wheels on the departure avoidance side, target brake fluid pressures Ps _{FL to} Ps _RR for each wheel cylinder are set (steps S34 to S36). ) And outputs a braking fluid pressure control command corresponding to this to the braking fluid pressure control circuit 7 (step S22).
Further, in order to suppress the driving torque of the vehicle, a target driving torque Trq is obtained by subtracting the braking torque g (Ps) generated by the departure prevention control from the driving torque f (Acc) according to the driver's accelerator operation. The calculation is performed (step S37), and a drive torque control command corresponding to the calculation is output to the drive torque controller 9 (step S44).

In this way, the departure warning prompts the driver to steer in the departure avoidance direction, and further suppresses the driving torque of the vehicle while generating a yaw moment in the departure avoidance direction to correct the own vehicle route, Prevent deviations.
Then, when the estimated deviation XS becomes less than the lateral displacement limit value Xc again due to the driver's own correction steering or the course correction by the yaw moment in the departure avoidance direction, the course correction is finished, and the departure estimated value XS is further alerted. When it becomes less than a predetermined value (Xw−Xh) smaller than the threshold value Xw, the departure warning is stopped.

In this way, when it is determined that the intentional lane change by the driver is accurate, it is determined that there is no intentional lane change, and it is determined that the host vehicle may deviate from the lane, Is corrected in the departure avoidance direction, it is possible to accurately prevent the vehicle from departing from the lane.
Further, a deviation estimated value XS is estimated based on at least the own vehicle speed V, the vehicle yaw angle φ with respect to the traveling lane, the lateral displacement X, and the curvature β of the forward traveling lane, and the deviation estimated value XS is equal to or greater than the lateral displacement limit value Xc. When it becomes, since it is judged that the own vehicle may deviate from the traveling lane, the degree of deviation from the traveling lane can be accurately determined.

Further, since the own vehicle route is corrected in the departure avoidance direction according to the deviation between the estimated departure value XS and the lateral displacement limit value Xc, the own vehicle route can be appropriately corrected.
In addition, the vehicle's course is corrected in the departure avoidance direction by generating a yaw moment in the departure avoidance direction in the own vehicle due to the braking force difference between the left and right wheels, so anti-skid control (ABS), traction control (TCS) If the braking fluid pressure control circuit 7 used for stability control (VDC) or the like is used, the vehicle path can be easily corrected without incurring an increase in cost.

  In the above embodiment, the raindrop detection sensor 16 detects the surrounding weather condition, but the present invention is not limited to this. In addition, the wiper operation state that wipes out water droplets such as the front window, rear window, and headlamps, and the fact that the light reaches wider than the headlamps and has excellent visibility from oncoming vehicles and pedestrians, fog, etc. The fog lamp used when the field of view deteriorates, and the warm air from the air conditioner is blown onto the window glass to evaporate the fog and dew on the inner surface. The ambient weather condition may be detected according to the operating state of a defogger (defroster) that warms the glass and melts frost and ice adhering to the outside.

In the above-described embodiment, the ambient brightness is detected according to ON / OFF of the headlamp, but the present invention is not limited to this. In addition, the ambient brightness may be determined by ON / OFF of the small lamp, or a light receiving sensor that detects the illuminance outside the vehicle on the instrument panel or the like.
In the above embodiment, the environmental mode is set by detecting ambient weather conditions and brightness, but the present invention is not limited to this. In addition, the environmental mode may be set by detecting the road surface condition of the road. In short, the environmental mode should be set by detecting at least one of the surrounding weather conditions, brightness, and road conditions. That's fine. Incidentally, the road surface state may be determined based on the road surface image data and the temperature, detected using a road surface discrimination sensor (GVS: Grand View Censor), or further acquired from the infrastructure.

  Furthermore, in the above-described embodiment, the road traffic situation mode is set by detecting the positional relationship (distance) with the front and rear vehicles, but the present invention is not limited to this. In addition, roads can be detected by detecting the relative speed between the host vehicle and the preceding and following vehicles, or by detecting traffic information such as traffic information or road attributes such as road type and number of lanes using a road traffic information communication system or navigation system. A traffic mode may be set. In short, the road traffic condition mode may be set by detecting at least one road traffic condition of the relative relationship between the own vehicle and the surrounding vehicle, traffic jam information, and road attributes.

Here, for example, when traffic jam information is used, a table as shown in FIG. 11 is referred to and a road traffic mode for quantifying the road traffic situation is set based on the traffic jam information and the vehicle speed V. The table in FIG. 11 may be set so that the road traffic situation mode is divided into stages 1 to 9 and the value of the road traffic situation mode increases as the degree of congestion is lower and the vehicle speed V is lower.
In the above embodiment, the possibility that the driver changes the lane without operating the direction indicator is determined based on the environmental mode, the road traffic condition mode, and the lateral movement state mode. It is not limited to the above, and it may be determined based on at least one mode.

  Further, in the above-described embodiment, when the direction indicator is not operated, the driver's intentional lane change is determined based on the steering angle δ and the steering angle change amount dδ. It is not limited. In addition, a driver's intentional lane change may be determined based on a steering operation state such as a steering torque or a steering angle deviation Δδ, or a driving operation state such as an accelerator operation state or a brake operation state. Furthermore, the intentional lane change of the driver may be determined based on the running state of the vehicle such as the lateral displacement X, the vehicle speed V, and the yaw rate φ. Also in these cases, the driver determines the possibility of changing the lane without operating the direction indicator, and changes the predetermined condition for determining that the lane change is intentional according to the determination result. To do.

  Furthermore, in the above-described embodiment, when it is determined that the vehicle departs from the lane, the yaw moment in the departure avoidance direction is generated to correct the own vehicle route. However, the present invention is not limited to this. That is, when it is determined that the vehicle departs from the lane, as shown in FIG. 12, if the steering actuator 25 applies steering torque in the departure avoidance direction to the steering shaft 26 to correct the own vehicle route, the host vehicle is not decelerated. Deviations can be prevented. In this case, the process of steps S30 to S37 may be omitted, and a new process for calculating the target steering torque Ts in the departure avoidance direction and adding the target steering torque Ts to the steering shaft may be added.

It is a schematic block diagram in the case of correcting the own vehicle course by generating a yaw moment in the departure avoidance direction in the own vehicle. It is a flowchart which shows the first half part of lane departure prevention control processing. It is a flowchart which shows the second half part of a lane departure prevention control process. It is a table used for setting the environmental mode. It is the map and table used for the setting of a road traffic condition mode. It is a map used for the setting of a horizontal movement state mode. It is a table used for the setting of the judgment flag Fj. It is a map used for setting the threshold value δs. It is a map used for setting the threshold value dδs. It is a map used for calculation of the gain K2. This table is used for setting the road traffic condition mode. It is a schematic block diagram in the case of correcting the own vehicle course by adding a steering torque in a departure avoidance direction to the steering system.

Explanation of symbols

6FL to 6RR Wheel cylinder 7 Braking fluid pressure control circuit 8 Control unit 9 Drive torque controller 13 Camera 14 Image processing device 15F / 15R Laser radar device 16 Raindrop sensor 17 Light switch 20 Steering angle sensor 22FL to 22RR Wheel rotation sensor 23 Direction indication Switch 24 Alarm device 25 Steering actuator

Claims (8)

In the lane change determination device that determines that the driver is changing the lane when the driving operation state of the driver or the driving state of the vehicle satisfies a predetermined condition,
A traveling scene detecting means for detecting a traveling scene of the vehicle, and a judging means for determining the possibility of the driver changing the lane without operating the direction indicator according to the traveling scene of the vehicle detected by the traveling scene detecting means When, and a changing means for changing the predetermined condition according to a result of said determination means determines,
The traveling scene detection means detects at least one traveling environment among ambient weather conditions, brightness, and road surface conditions,
The determination means determines that a driver is less likely to change lanes without operating a direction indicator as visibility of a front view decreases according to the driving environment. apparatus. The lane change determination device according to claim 1, wherein the travel scene detection unit detects at least one road traffic situation of a relative relationship between the own vehicle and a surrounding vehicle, traffic jam information, and road attributes. The traveling scene detecting means, the lane change determination device according to claim 1 or 2, characterized in that for detecting the lateral movement state of the vehicle with respect to the traffic lane. A lane change determination device according to any one of claims 1 to 3 , a departure determination means for detecting the degree of departure of the host vehicle relative to the traveling lane and determining the possibility of lane departure, and the lane change determination device When it is not determined that the driver is changing lanes and the departure determination means determines that there is a possibility of departure from the lane, the vehicle course is corrected to the departure avoidance direction to prevent lane departure. A lane departure prevention device comprising: a departure prevention means. The deviation determining means calculates an estimated lateral displacement from the center of the lane of the vehicle in the future based on at least the vehicle speed, the yaw angle and lateral displacement of the vehicle with respect to the traveling lane, and the curvature of the forward traveling lane. The lane departure prevention apparatus according to claim 4 , wherein when the estimated displacement value is equal to or greater than a lateral displacement limit value, it is determined that there is a possibility of lane departure. 6. The lane departure prevention apparatus according to claim 5 , wherein the departure prevention means corrects the own vehicle path in a departure avoidance direction in accordance with a deviation between the lateral displacement estimated value and the lateral displacement limit value. 7. The vehicle according to claim 4 , wherein the departure prevention means is configured to correct the own vehicle path by generating a yaw moment in the departure avoidance direction in the own vehicle by a difference in braking / driving force between the left and right wheels. The lane departure prevention apparatus according to claim 1. The lane departure according to any one of claims 4 to 6 , wherein the departure prevention means is configured to correct the own vehicle course by adding a steering torque in a departure avoidance direction to the steering system. Prevention device.

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