JP4576914B2 - Vehicle lane travel support device - Google Patents

Description

  The present invention relates to a vehicle lane travel support device, and more particularly, a steering control unit that operates according to a steering wheel operation of a driver and can control a steering state according to a road surface traveling state of the vehicle, and a road surface by an imaging unit. The present invention relates to a vehicle lane travel support device that includes travel lane detection means for detecting travel lanes from images that are continuously captured, and that assists the vehicle to travel in the travel lane.

  The vehicle lane travel support device includes steering control means that operates according to the steering wheel operation of the driver and can control the steering state according to the road surface traveling state of the vehicle. Lane maintenance assist that assists in driving inside is basic, but beyond the driving support, steering control is automatically performed regardless of the driver's operation, and the vehicle keeps traveling in the driving lane Devices are also known that can be controlled.

  For example, in Patent Document 1 below, while searching for a traveling route, an optimal target route is set on the traveling route, and vehicle traveling control is performed to assist the vehicle traveling on the target route. An automatic traveling apparatus configured as follows has been proposed. That is, an appropriate target route is set in the travelable area while searching for the travelable area by recognizing the road edge based on the image obtained by capturing the area in the traveling direction of the vehicle by the imaging device. It is described that an optimal control target amount for joining the vehicle to the target route is obtained in accordance with the traveling state of the vehicle, and the vehicle is controlled according to the control target amount.

  Alternatively, in Patent Document 2 below, for example, a white line marked on both sides of the passage is used as a guide band in order to display a safety passage on the floor surface of a plant, factory, etc., and cornering in a narrow space is easy. For the purpose of being able to do so, the white line provided on the floor surface is used as it is as a guide band to show the limit of the safety passage, and the steering amount is calculated from the current direction of the traveling vehicle and the angle of the corner part A traveling vehicle guidance device configured to perform cornering has been proposed.

  Further, Patent Document 3 below proposes an automatic steering apparatus for an automobile that can travel without departing from the front traveling lane even if the driver does not operate the steering wheel. This Patent Document 3 includes a photographing means for photographing a path in the lower right direction of a car, a recognition means for recognizing a line indicating a boundary of an adjacent traveling lane among roads photographed by the photographing means, and this recognition. Distance detecting means for detecting the distance from the reference position of the line recognized by the means, steering angle control means for generating a steering angle control signal corresponding to the distance detected by the distance detecting means, and the steering angle control means A steering angle driving means for changing the traveling direction of the vehicle in response to a steering angle control signal from the vehicle, and a distance detected by the distance detection means by the operation of the steering angle control means by the steering angle control signal is predetermined. It is described that the value is held.

JP-A-2-48704 JP-A-2-27408 JP 60-37011 A

  According to the devices described in the above-mentioned patent documents, it is possible to perform cornering along a traveling lane of a vehicle or the like detected by an image. In this case, as a realistic response, it is not always necessary to automatically steer regardless of the operation of the driver. For example, the vehicle maintains the center of the traveling lane with respect to the steering wheel operation by the driver. By adding the steering torque in this way, the operation load on the steering wheel can be reduced and the cruise operation can be supported.

  In such a lane travel support device, it is important to appropriately and stably detect a travel lane on the road surface from an image captured by a camera. Usually, on the road surface, marking lines (lane marks) are painted according to various purposes including a lane boundary line that identifies the boundary of the driving lane (lane), not only a solid line but also a broken lane mark, There are lane marks of different colors such as white or yellow, and there are also those in which these are combined. In addition, the lane mark is not limited to a straight line, but there is a curved line. In order to obtain a curvature for specifying the lane mark of the curved line, it is necessary to reliably detect the lane mark far away. Therefore, a forward monitoring camera capable of detecting a lane mark with high accuracy to a long distance is required as an imaging unit provided for the lane travel support device.

  By the way, some recent vehicles are equipped with a front monitoring camera and a rear monitoring camera for confirmation of parking in front of or behind the vehicle and for parking assistance. However, these existing front and rear monitoring cameras can only secure a nearby image, and distant images are unclear, so the curvature in the traveling direction cannot be accurately determined for a curved lane mark. Therefore, it is necessary to obtain the curvature from the past travel locus and substitute it, but the existing camera is not diverted to detect such lane marks, and a high-performance front monitoring camera is adopted separately. It was an expensive device.

  On the other hand, although the navigation system is disclosed in the above-mentioned Patent Document 1, the recent progress of the navigation apparatus is remarkable, and the current position of the vehicle is determined with high accuracy by using GPS (Global Positioning System) and inertial navigation. It has become possible to identify. Accordingly, the road shape information in the traveling direction of the vehicle can be detected by such a navigation device, and the position coordinates at a predetermined position in the traveling direction of the vehicle can be detected as the road shape information. However, when the position coordinates in the traveling direction of the vehicle are specified using only the detection information of the navigation device, the place depends on the accuracy of the navigation device, and a high-performance device is required and expensive. In addition, when the above-described high-performance front monitoring camera is required, it becomes a very expensive device, which is not completely worth the cost.

  Therefore, the present invention includes a steering control unit that can control the steering state, and a traveling lane detecting unit that detects a traveling lane from the captured image, and by using these, a vehicle that assists the vehicle to travel in the traveling lane. In the lane driving support device, the road curvature in the vehicle traveling direction is calculated based on the detection information of the navigation device, and the road curvature along the moving track of the vehicle is calculated based on the detection information of the driving lane detecting means, and these are collated. It is an object of the present invention to provide an inexpensive lane travel support device that can perform lane travel support of a vehicle based on the road curvature in the vehicle traveling direction estimated as described above.

In order to achieve the above object, the present invention provides a steering control means that operates in accordance with a steering wheel operation of a driver and can control a steering state in accordance with a road surface traveling state of the vehicle, and a parking assist attached to the vehicle. Including a traveling lane detecting means for detecting a lane mark indicating the traveling lane from an image obtained by continuously capturing a road surface with a front or rear surveillance camera , and position coordinates for a predetermined distance in the traveling direction of the vehicle A navigation device for detecting road shape information, state detection means for detecting the steering state and traveling state of the vehicle including the yaw rate and vehicle speed of the vehicle, detection results of the traveling lane detection means, and steering of the vehicle depending on the state and the traveling state, the vehicle state calculating a state quantity including a relative position index indicating the relative position with respect to the traveling lane of the vehicle And calculating means, the relative position index of said vehicle said vehicle state quantity calculating means is calculated, and based on the yaw rate and the vehicle speed the state detecting unit detects, calculates the position coordinates of the vehicle in the plane coordinates, of the vehicle A position coordinate at the center of the traveling lane is calculated based on the position coordinates and the relative position index of the vehicle, the calculation result is accumulated, the position coordinate at the center of the traveling lane is assumed to be an arc, and the vehicle is based on the radius of the arc. A first road curvature calculating means for calculating a first road curvature which is a road curvature of the traveling locus of the vehicle, and a traveling direction of the vehicle based on position coordinates for a predetermined distance of the traveling direction of the vehicle detected by the navigation device second and second road curvature calculating means for calculating a road curvature, and compares the calculation result of the calculation results and the first road curvature calculating unit of the road curvature calculating means of the second A deviation of a road distance with respect to the second road curvature of the first road curvature is obtained, a position of the vehicle with respect to the second road curvature is identified based on the deviation, and the specific position and the second road Road curvature estimation means for estimating the road curvature in the traveling direction of the vehicle based on the calculation result of the curvature calculation means, the road curvature estimated by the road curvature estimation means, and the steering state and running state of the vehicle detected by the state detection means And a target state quantity setting means for setting a target state quantity for the vehicle based on the result, and according to a comparison result between the target state quantity set by the target state quantity setting means and the state quantity calculated by the vehicle state quantity calculation means The vehicle is configured to support traveling in the travel lane of the vehicle.

As the index representing the state quantity, in addition to the lane position serving lateral position of the vehicle in the traveling within the lane, its a differential value lane position variation speed, a yaw angle of the vehicle, and there is a yaw rate. The steering control means may include an electric power steering system, for example.

  In the vehicle lane travel assistance device, as described in claim 2, the road curvature estimation means may be configured to estimate the road curvature by applying clothoid information of a road on which the vehicle travels.

In the vehicle lane travel assistance device according to each of the above claims, as described in claim 3 , the target state quantity set by the target state quantity setting means and the state quantity calculated by the vehicle state quantity calculating means Provided with a correction steering means for correcting the steering control by the steering control means based on the sum of the feedback control quantity according to the difference between them and the feedforward control quantity according to the road curvature estimated by the road curvature estimation means It is good to do. In addition to or separately from the correction steering means, depending on the comparison result between the target state quantity set by the target state quantity setting means and the state quantity calculated by the vehicle state quantity calculation means, It may be provided with alarm means for alarming.

Since this invention is comprised as mentioned above, there exist the following effects. That is, in the vehicle lane travel support device configured as described in claim 1 , the travel lane is determined from images obtained by continuously capturing the road surface with a front or rear monitoring camera for parking support mounted on the vehicle. Detect the lane mark to be displayed, calculate the position coordinates at the center of the lane based on the yaw rate and the vehicle speed, accumulate the calculation results, assume the position coordinates at the center of the lane as an arc, and based on the radius of the arc a first road curvature of the running path of the computed vehicle, a second road curvature direction of travel of the vehicle calculated based on the traveling direction of the position coordinates of the predetermined distance of the vehicle detected by the navigation device matching to a deviation of the road distance, based on the deviation to identify the position of the vehicle relative to the second road curvature based on the calculation result of the particular position and the second road curvature calculating means Since the traveling direction of the road curvature of the vehicle is accurately estimated without relying heavily on the surveillance camera accuracy, utilizing the detection information of the navigation device, it can also be applied to the lane mark of the curve, Appropriate lane driving assistance can be provided. In particular, an existing inexpensive camera can be used as a parking assistance monitoring camera, and not only the front monitoring camera but also a rear monitoring camera can be used.

  In particular, if the road curvature estimation means is configured as described in claim 2, the road curvature can be easily and appropriately estimated by the clothoid information of the traveling road.

Furthermore, according to the structure as claimed in claim 3, the corrective steering means based on the detection information of the navigation device, it is possible to smoothly perform the lane running support of the vehicle.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows a configuration of a vehicle lane driving support apparatus according to an embodiment of the present invention. A front monitoring camera CMf configured with, for example, a ccd camera as an imaging unit in front of the vehicle (upward in FIG. 1). Is arranged, and a rear monitoring camera CMr is also arranged behind the vehicle. However, any one of the cameras may be provided. Moreover, an electric power steering system EPS is provided as the steering control means of the present embodiment. Such an electric power steering system EPS is already on the market, and the steering torque acting on the steering shaft by the operation of the steering wheel SW by the driver is detected by the steering torque sensor TS, and according to the value of the detected steering torque. The EPS motor (not shown in FIG. 1) is controlled to steer and drive the wheels in front of the vehicle (represented by WH as representative of all wheels in FIG. 1) via a reduction gear and a rack and pinion (not shown). This reduces the operator's steering operation force (steering operation force).

  In the present embodiment, as shown in FIG. 1, an electronic control unit ECU1 for image processing and an electronic control unit ECU2 for steering control are provided, and both are connected via a communication bus. A camera CMf (and CMr) is connected to the electronic control unit ECU1, and an image signal is input to the electronic control unit ECU1. Further, a steering angle sensor SS that detects the steering angle of the wheel WH ahead of the vehicle, a vehicle body speed sensor VS that detects the vehicle body speed, and a yaw rate sensor YS that detects the yaw rate of the vehicle are connected to the electronic control unit ECU1. However, since the electronic control units ECU1 and ECU2 are configured to be able to transmit and receive signals to each other as will be described later, they may be connected to the electronic control unit ECU2. Instead of the vehicle body speed sensor VS, a wheel speed sensor (not shown) for detecting the wheel speed of each wheel may be provided, and the vehicle body speed may be estimated based on the detected wheel speed. On the other hand, the electronic control unit ECU2 is connected to the steering torque sensor TS and the rotation angle sensor RS for detecting the rotation angle of the EPS motor on the input side, and to the EPS motor on the output side.

  Furthermore, a navigation device NAV equipped with GPS and inertial navigation is connected to the electronic control unit ECU1 (or ECU2), and road shape information in the vehicle traveling direction detected thereby is input to the electronic control unit ECU1. . The road shape information at this time includes position coordinates at a predetermined position in the vehicle traveling direction, and the navigation device NAV can use a commercially available device as long as it can extract the position coordinates at the predetermined position in the vehicle traveling direction. Since the basic configuration may be the same as that of a commercially available apparatus, description thereof is omitted.

  FIG. 2 shows a system configuration of the present invention. An image processing system (upper part of FIG. 2) and a steering control system (lower part of FIG. 2) are connected via a communication bus. The image processing system according to this embodiment includes an electronic control unit ECU1 including a CPU for image processing, a frame memory, and the like, a front monitoring camera CMf and a rear monitoring camera CMr, a yaw rate sensor YS, a steering angle sensor SS, and a vehicle body speed sensor VS. And a navigation device NAV. Further, in the steering control system of the present embodiment, a steering torque sensor TS and a rotation angle sensor RS are connected to an electronic control unit ECU2 having a CPU, ROM and RAM for electric power steering control, and a motor drive circuit AC2 is used. An EPS motor MT is connected via Further, in the present embodiment, an alarm device WA that outputs an alarm display and an audio alarm is connected via an alarm electronic control unit ECU3 (not shown in FIG. 1).

  Each of these electronic control units ECU1 to ECU3 is connected to a communication bus via a communication unit including a CPU, ROM and RAM for communication, and transmits information necessary for each control system from other control systems. be able to. Further, although not shown in the figure, an active steering system, a brake control system, a throttle control system, etc. may be connected to the communication bus so that each system can share system information. Good. As shown in FIG. 1, an operation switch OS is connected to the electronic control unit ECU1 (or ECU2), and the driving support control is configured to be started by the operation of the operation switch OS by the driver. .

  In the lane travel support apparatus configured as described above, the lane travel support (lane keep assist) control unit is configured as shown in the control block diagram of FIG. 3 and is captured by the camera CMf (or CMr). The image information is image-processed by the electronic control unit ECU 1 shown in FIG. 2 to detect the traveling lane. The electronic control unit ECU1 includes a lane recognition calculation unit M1 serving as lane detection means. Here, the lateral position y (lane position) of the vehicle in the travel lane and the yaw angle ψ relative to the travel lane are calculated. The In addition, about the detection of the driving | running lane by image processing, any well-known method other than the method described in the above-mentioned patent document 1 may be used.

Based on the calculation result by the lane recognition calculation unit M1 and the detection signals of the yaw rate sensor YS and the steering angle sensor SS, the lane position y and the lane lateral movement speed dy ( The current vehicle state quantity X is estimated and calculated by using the lateral movement speed of the vehicle in the travel lane and the yaw angle ψ and the yaw rate γ as factors. That is, if the vehicle state quantity is X, the state quantity output is Y, and the road model input is U, X = [y, dy, ψ, γ] ^T , Y = [y, dy, ψ, γ] ^T , U = [δf, ρ] ^T. Note that δf is a steering angle detected by the steering angle sensor SS, ρ is a road curvature of the traveling road, and is estimated and calculated from the above-described camera image, for example. When the state quantity estimated value is Xe and the observer gain is L, the following state equation is established, and the state quantity output Y is Y = C · Xe.
dXe / dt = A.Xe + B.U + Rl.L. (X-Xe)

The model constants A, B, and C in the above state equation are as shown below.
A = [a11 a12 a13 a14; a21 a22 a23 a24; a31 a32 a33 a34; a41 a42 a43 a44]
B = [b11 b12; b21 b22; b31 b32; b41 b42]
C = [1 0 0 0; 0 1 0 0; 0 0 1 0; 0 0 0 1]
Rl is a factor indicating the lane detection state of the image recognition result. For example, the state where the traveling lane is detected is “1”, and the state where the lane is not detected is “0”. Thus, the configuration is such that the lateral position of the vehicle in the travel lane is estimated only when the continuous line portion of the lane mark is detected, or the travel lane is only detected when the continuous line portion of the lane mark is detected. The lateral position of the vehicle in the vehicle can be reflected in the estimation result.

  On the other hand, a relative position index representing a relative position of the vehicle with respect to the travel lane is calculated in the state quantity calculation unit M2, and based on the relative position index, the detected yaw rate of the yaw rate sensor YS, and the detected vehicle body speed (vehicle speed Vx) of the vehicle body speed sensor VS. The first road curvature calculation unit M3 calculates the first road curvature. FIG. 5 shows a travel lane center trajectory (solid line) on absolute coordinates and a travel trajectory (broken line) of the vehicle VH. The position coordinates of the lane center are represented by (xlc, ylc), and the vehicle position coordinates are represented by (xv, yv). In the figure, Ca indicates the arc center of the traveling lane center locus.

The first road curvature calculation algorithm in the present embodiment is as follows. That is, the plane lane coordinates (absolute coordinates) shown in FIG. 5 are generated based on the vehicle lane position y obtained on the image as described above, and the vehicle position coordinates are calculated based on the detected yaw rate γ and the vehicle speed Vx. The position coordinate at the center of the lane is calculated based on the calculation result and the lane position y, and this is stored and the curvature is calculated by the method of least squares. Specifically, first, the position coordinates (xv, yv) of the vehicle are obtained as follows based on the detected yaw rate γ and the vehicle speed Vx for each control cycle.
xv = ∫∫Vx · cos (ψ + β) dt dt = ΣVx · Δt · cos (ψ + β)
yv = ∫∫Vx · sin (ψ + β) dt dt = ΣVx · Δt · sin (ψ + β)

The yaw angle ψ in the above equation can be obtained as ψ = ∫γdt based on the yaw rate γ, and the side slip angle (slip angle) β can be obtained by the following equation.
β = [{1- (Mv / 2L) ・ Lf / (Lr ・ Cr)} / (1 + K ・ Vx ² )] ・ (Lr / L) ・ δf
Where Mv is the vehicle body mass, L is the wheel base, Lf and Lr are the distance between the center of gravity of the vehicle and the center of the front wheel axle and the center of the rear wheel axle (L = Lf + Lr), and Cr is the cornering factor of the rear wheel , K is the stability factor, Vx is the vehicle speed, and δf is the steering angle.

Next, every time the lane position y is acquired, the position coordinates of the lane center offset from the position coordinates of the vehicle are obtained. Basically, calculation is performed so that the yaw angle ψ is zero with respect to the vehicle traveling direction, and if the error is large, the measured yaw angle is corrected. That is, the position coordinates (xlc, ylc) at the center of the lane are the offsets in the direction perpendicular to the position coordinates (xv, yv) of the vehicle at the time of measurement of the lane position y (the lane position at the time of measurement is yc). Addition can be obtained as follows.
xlc = xv + (-yc) .cos (ψ + 90deg)
ylc = yv + (-yc) · sin (ψ + 90deg)

  Thus, if a part of the past coordinates of the position coordinates (xlc, ylc) at the center of the lane is taken out and a circle parameter is obtained by the method of least squares assuming that the center locus of the traveling lane is an arc, the radius is calculated. It becomes a road diameter, and the curvature thereof is the first road curvature (ρv (n)).

  Further, among the road shape information detected by the navigation device NAV, position coordinates for a predetermined distance in the traveling direction (front) of the vehicle (VH indicated by a broken line in FIG. 6) are input to the second road curvature calculation unit M4. Here, the second road curvature at a position separated by a predetermined distance in the traveling direction (forward) of the vehicle VH is calculated. Specifically, as shown in FIG. 6, an arc is fitted to several points among a plurality of road coordinate points (position coordinates indicated by black points in FIG. 6) detected by the navigation device NAV. The curvature is calculated. In order to fit the arc to the road position coordinates at this time, for example, a method of obtaining an arc passing through three points or a method of obtaining an arc so as to minimize the square error from the coordinates of four or more points (least square method). Apply. Thus, as the road shape information in the vehicle traveling direction, the second road curvature with respect to a predetermined position in the traveling direction (front) of the vehicle VH is accumulated, and the map shown in FIG. 7 is formed. In FIG. 7, road curvature (ρ) is used.

Then, in the own vehicle position specifying unit M5, as shown in FIG. 8, every time the position coordinates (own vehicle locus coordinates) are measured, the own vehicle locus road curvature data string (first road curvature data string) (ρv ( n), ρv (n-1), ρv (n-2), ρv (n), ..., ρv (nk)) and the navigation road curvature data string (second road curvature data string) The deviation of the road distance (x (n), x (n-1), x (n-2), x (n), ..., x (nk)) is obtained, and the average value (= (1 / k) · Σx (ni), where Σ is i = 1 to k). Thereby, the shift | offset | difference with respect to the 2nd road curvature of a 1st road curvature becomes clear, and the position of the vehicle VH with respect to a 2nd road curvature is pinpointed. Accordingly, as shown in FIG. 9, if the vehicle trajectory road curvature data sequence indicated by the broken line is shifted by the average value (= (1 / k) · Σx (ni)), the navigation road curvature data sequence at that time is changed. Corresponding points can be estimated. Thus, the road curvature estimation unit M6 estimates the clothoid coefficient (A) at that time. The relationship between road curvature (ρ) and clothoid coefficient (A) is ρ = L / A ² (L represents the distance traveled), and estimation of clothoid coefficient (A) is an estimate of road curvature (ρ). means.

When estimating the road curvature (ρ) in the road curvature estimation unit M6, for example, if there is a delay of xd in the road distance, the road curvature (ρ) is calculated as a curvature recognition delay distance as shown in FIG. It is better to replace with the road curvature (ρ ') corrected by (xd). For example, when the vehicle traveling road is formed along a clothoid, ρ ′ is replaced by (ρ + xd / A ² ) (A is a clothoid coefficient). On the contrary, when the road curvature decreases, ρ ′ is replaced with (ρ−xd / A ² ).

  The road curvature (ρ) estimated as described above is input to the target state quantity calculation unit M7. Based on the road curvature (ρ), the target state quantity calculation unit M7 calculates the target state quantity as follows. The That is, based on the road curvature (ρ) estimated by the road curvature estimation unit M6 in addition to the steering angle δf detected by the steering angle sensor SS, the vehicle speed (vehicle speed Vx) detected by the vehicle speed sensor VS, and the like, The target state quantity calculation unit M7 calculates a target state quantity consisting of the following four factors.

  First, the target lane position yt relative to the lateral position (lane position) of the vehicle in the travel lane is set to yt = 0 starting from the center of the travel lane (center between lane boundary lines). Then, with respect to the target lane lateral movement speed dyt, dyt = 0 is set so that the vehicle moves along the center of the travel lane without sideways swinging. Further, the target yaw angle ψt is set to ψt = C · ρ. Note that C is a conversion constant from the road curvature (ρ) to the target yaw angle ψt. Then, based on the vehicle body speed (vehicle speed) Vx and the road curvature (ρ), the target yaw rate γt is set as γt = Vx · ρ.

Thus, the difference between the calculation result (target state quantity) of the target state quantity calculation unit M7 and the calculation result (current state quantity) of the state quantity calculation unit M2 is calculated, and based on this difference, the feedback control calculation unit A torque command value is calculated at M8. That is, in the feedback control calculation unit M4, the difference between the 4-factor target value (t is added) and the estimated value (e is added) representing the target state quantity is weighted by the control gains K1 to K4. An error feedback term for lateral displacement is formed, and a steering angle feedforward term δff (ρ) corresponding to the road curvature (ρ) is added to the sum of these, and the target rotation angle (target steering angle) is as follows: It is set as δswt.
δswt = K1 ・ (yt−ye) + K2 ・ (dyt−dye) + K3 ・ (ψt−ψe) + K4 ・ (γt−γe) + δff (ρ)

The above δff (ρ) is calculated as the steering angle theoretical value in the road curvature (ρ) derived from the two-wheel model as follows (where Vx is the vehicle speed, L is the wheelbase, and K is the stability) Factor).
δff (ρ) = Vx · ρ / Vx · L (1 + K · Vx ² )

Then, according to the difference between the target rotation angle (target steering angle) δswt and the actual rotation angle (actual steering angle) δsw detected by the rotation angle sensor RS, and the additional steering torque feedforward term Tff (ρ) The additional steering torque command value Tadd is calculated as follows (where K5 is a control gain).
Tadd = K5 · (δswt−δsw) + Tff (ρ)
The additional steering torque feedforward term Tff (ρ) is calculated as follows.
Tff (ρ) = fatff (βff (ρ) + δff (ρ))

In the above equation, fatff (α) is a function representing the self-aligning torque with respect to the tire slip angle (α), and has a relationship shown in FIG. 4, for example. Βff (ρ) is a steady vehicle body slip angle at the road curvature (ρ), and is obtained as follows. The steady vehicle body slip angle is the vehicle body slip angle when traveling on a road having a constant road curvature at a constant vehicle speed.
βff (ρ) = [{1− (Mv / 2L) ・ (Lf / (Lr ・ Cr)) ・ Vx ² } / (1 + K ・ Vx ² )] ・ (Lr / L) ・ δff (ρ)
Where Mv is the vehicle body mass, L is the wheel base, Lf is the distance from the center of gravity of the vehicle to the center of the front axle, Lr is the distance from the center of gravity of the vehicle to the center of the rear axle, Cr is the cornering factor of the rear wheel, and Vx is Vehicle speed and K are stability factors.

  The additional steering torque command value Tadd calculated as described above is transmitted to the electronic control unit ECU2 (FIG. 2) for steering control, and the torque command value Tadd is normally set by the electric power steering control unit M9 (FIG. 3). The electric power steering system EPS is controlled by being added to the power steering control amount, and the correction steering according to the present invention is performed. Further, if necessary, the torque command value Tadd is supplied to the alarm output unit M10, and depending on the magnitude of the torque command value Tadd, in other words, the position of the vehicle from the center of the travel lane, A warning indicating fear is output, and the driver is alerted. In addition, it is good also as issuing a warning according to the estimation result (calculation result of the state quantity calculating part M2) of the horizontal position of the vehicle in a driving | running | working lane, without using torque command value Tadd.

Furthermore, as another embodiment of the present invention, among the road shape information detected by the navigation device NAV, position coordinates at a predetermined position in the traveling direction (front) of the vehicle (VH indicated by a broken line in FIG. 11) are obtained. The position coordinates may be used and input to the electronic control unit ECU1. Specifically, as shown in FIG. 11, from a plurality of road coordinate points (position coordinates indicated by black dots in FIG. 11) detected by the navigation device NAV, the least square method or the like is used as described above. The road curvature (ρ) in the vicinity of the own vehicle position is estimated, and the xy coordinates are set with the own vehicle position of the vehicle VH as the origin and the axis parallel to the tangent indicated by the two-dot chain line in FIG. 11 as the x axis. The Then, the x coordinate value (xlt) of the target coordinate point (intersection point x in FIG. 11) in the vehicle traveling direction is set based on the vehicle speed Vx of the vehicle VH, and the y coordinate value (ylt) is further based on the x coordinate value (xlt). ) Is calculated as follows (note that R below is R = 1 / ρ).
ylt = (yt−ye) + R ・ (1−cos (sin ⁻¹ (xlt / R))

Thus, the target steering angle (δswt) is set as follows according to the lateral displacement (ylt−xlt · tan (ψ + Vx · γ)) at the target coordinate point in the vehicle traveling direction (K6 is Control gain).
δswt = K6 ・ (ylt−xlt ・ tan (ψ + Vx ・ γ))

Thereafter, as in the above-described embodiment, the additional steering torque command value Tadd is calculated as follows, and feedback according to the displacement in the lateral direction of the vehicle is performed, and thereafter, the same processing as in the above-described embodiment is performed ( K7 is a control gain).
Tadd = K7 ・ (δswt−δsw)

It is a block diagram which shows one Embodiment of the lane travel assistance control apparatus of the vehicle of this invention. It is a block diagram which shows the structural example of the lane driving assistance control apparatus containing the steering control means in one Embodiment of this invention. It is a block diagram which shows the control aspect in one Embodiment of this invention. In one Embodiment of this invention, it is a graph which shows an example of the characteristic of the self-aligning torque with respect to a tire slip angle. It is a graph explaining the own vehicle locus road curvature data sequence (1st road curvature data sequence) in one embodiment of the present invention. It is a graph explaining a navigation road curvature data sequence (2nd road curvature data sequence) in one embodiment of the present invention. It is a graph which shows the data which accumulate | stored the calculation result of the 2nd road curvature in one Embodiment of this invention using the change of the road curvature with respect to road distance. It is a graph which shows the relationship between the own vehicle locus road curvature data sequence and a navigation road curvature data sequence in one Embodiment of this invention. It is a graph which shows the condition which shifts the own vehicle locus road curvature data sequence in one Embodiment of this invention, and estimates the point corresponding to a navigation road curvature data sequence. In one Embodiment of this invention, it is a graph which shows the correction | amendment condition of a road curvature in case there exists a delay in the estimation of a road curvature. It is a graph explaining the setting of the target coordinate point in other embodiment of this invention.

Explanation of symbols

SW Steering wheel VH Vehicle WH Wheel EPS Electric power steering system NAV Navigation device CMf Front monitoring camera CMr Rear monitoring camera TS Steering torque sensor SS Wheel steering angle sensor RS Rotation angle sensor YS Yaw rate sensor VS Car body speed sensor OS Operation switch

Claims (3)

The road surface is continuously connected by a steering control means that operates according to the steering wheel operation of the driver and can control the steering state according to the road running state of the vehicle, and a front or rear monitoring camera for parking assistance attached to the vehicle. A travel lane detecting means for detecting a lane mark indicating the travel lane from the captured image, and a navigation device for detecting road shape information including position coordinates for a predetermined distance in the traveling direction of the vehicle, state detecting means for detecting the steering state and the running state of the vehicle including the yaw rate and the vehicle body speed of the vehicle based on the steering state and the running state of the detection result and the vehicle of the travel lane detecting unit, wherein the vehicle a vehicle state quantity calculating means for calculating a state quantity including a relative position index indicating the relative position with respect to the travel lane, the said vehicle state quantity calculating means Based on the calculated relative position index of the vehicle, the yaw rate and the vehicle body speed detected by the state detection means, the position coordinate of the vehicle in the plane coordinates is calculated, and based on the position coordinate of the vehicle and the relative position index of the vehicle The position coordinate at the center of the travel lane is calculated, the calculation result is accumulated, the position coordinate at the center of the travel lane is assumed to be an arc, and the road curvature of the travel locus of the vehicle based on the radius of the arc is a first A first road curvature calculating means for calculating a road curvature; and a second road curvature for calculating a second road curvature in the traveling direction of the vehicle based on position coordinates for a predetermined distance in the traveling direction of the vehicle detected by the navigation device. a road curvature calculating means, calculation results and the second road songs calculation result with the collation to the first road curvature of the first road curvature calculating means of the second road curvature calculating means A deviation of the road distance to, on the basis of the deviation locates the vehicle with respect to the second road curvature, the traveling direction of the vehicle based on the calculation result of the specific position and the second road curvature calculating means Road curvature estimation means for estimating the road curvature of the vehicle, and a target state for setting a target state quantity for the vehicle based on the road curvature estimated by the road curvature estimation means and the steering state and running state of the vehicle detected by the state detection means An amount setting unit, and assists the vehicle in traveling in the travel lane according to a comparison result between the target state amount set by the target state amount setting unit and the state amount calculated by the vehicle state amount calculating unit. A vehicle lane travel support apparatus characterized by the above.   2. The vehicle lane travel support apparatus according to claim 1, wherein the road curvature estimation means is configured to estimate the road curvature by applying clothoid information of a road on which the vehicle travels. Feedback control amount according to the difference between the target state quantity set by the target state quantity setting means and the state quantity calculated by the vehicle state quantity calculating means, and feedforward according to the road curvature estimated by the road curvature estimating means based on the sum of the control amount, the steering control unit according to the lane running support system for a vehicle according to claim 1 or 2, characterized in that it comprises a corrective steering means for modifying the steering control.

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