JP4423926B2 - 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. The lane keep assist is basic so that the vehicle can travel inside, but further, the vehicle can maintain the traveling in the traveling lane beyond the driving assistance by automatically performing the steering control regardless of the operation of the driver. Such a control device is also known.

  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 particular, since there is a blank portion in a broken lane mark or a lane mark in which peeling occurs, it is necessary to detect a short solid line portion with high accuracy. Therefore, a high-performance forward monitoring camera is required as an imaging means used for the lane travel support device so that the lane mark can be reliably detected far away.

  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 monitoring cameras and rear monitoring cameras can only secure a nearby image, and distant images are unclear, and therefore, distant lane marks cannot be detected in the blank portion. Therefore, an existing camera is not diverted for detecting such a lane mark, and a high-performance front monitoring camera is separately employed, resulting in an expensive device.

  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. It is an object of the present invention to provide a lane travel support device that can appropriately provide lane travel support for a vehicle even if an existing inexpensive camera is diverted without greatly depending on the accuracy of the imaging means. .

In order to achieve the above object, the present invention provides a steering control means 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 a vehicle, and an imaging means for vehicle vicinity monitoring. A travel lane detecting means for detecting a travel lane from images obtained by continuously imaging the road surface by controlling the steering control means so that the vehicle travels in the travel lane detected by the travel lane detection means, The vehicle lane travel support apparatus for supporting travel of the vehicle in the travel lane includes a vehicle motion model and a road model corresponding to a road curvature, and the vehicle motion model and the road according to claim 1. according based rather state equation model, according to the steering state and the running state of the detection result and the vehicle of the travel lane detecting unit, wherein in said traveling in lane Lateral position of both lateral moving speed, a vehicle state estimation means for estimating a state quantity including the yaw angle and yaw rate, detecting the continuous line portion of the lane mark the travel lane detecting means for marking the driving lane -out based on the detection value when the lateral position of the vehicle in the traveling within the lane containing blank part of the lane mark, always estimated according to the state equation, marking the traveling lane detecting means said traveling lane Vehicle state estimating means configured to reflect the lateral position of the vehicle in the traveling lane in the estimation result only when a continuous line portion of the lane mark to be detected is detected, and to the steering state and the traveling state of the vehicle Target state quantity setting means for setting a target state quantity for the vehicle based on the target state quantity set by the target state quantity setting means and the vehicle state estimation Stage in which is configured to support the travel of the travel in the lane of the vehicle in accordance with the comparison result of the estimated state quantity.

Examples of the index indicating the steering state and traveling state of the vehicle in the vehicle state estimating means include a steering angle and a yaw rate, and the index indicating the steering state and traveling state of the vehicle in the target state quantity setting means is, for example, There are steering angle and body speed . The steering control means may include an electric power steering system, for example.

And, according to claim 2 , by the alarm means for warning the driver based on the estimation result of the lateral position of the vehicle in the travel lane by the vehicle state estimation means and the steering control means It is preferable that at least one of correction steering means for correcting the steering control is provided.

Since this invention is comprised as mentioned above, there exist the following effects. That is, in the vehicle lane travel support apparatus configured as described in claim 1, the state quantity including the lateral position of the vehicle in the travel lane is estimated by the vehicle state estimation means based on the vehicle model and the road model. Therefore, the image pickup means for monitoring the vicinity of the vehicle can be used without largely depending on the accuracy of the image pickup means, and the vehicle lane traveling support can be appropriately performed even with an existing inexpensive camera. Further, not only the front monitoring camera used for vehicle vicinity monitoring but also a rear monitoring camera can be used. In particular, the vehicle state estimating means-out based on the detection value when the traveling lane detecting means detects the continuous line portion of the lane mark marking the driving lane, the vehicle in the travel lane containing blank part of the lane mark The lateral position is always estimated according to the state equation based on the vehicle motion model and the road model, and only when the traveling lane detecting means detects the continuous line portion of the lane mark indicating the traveling lane, the lateral position of the vehicle in the traveling lane is detected. Since it is configured to reflect the direction position in the estimation result, even if there is a blank part such as a broken lane mark or a lane mark with peeling, the lateral position of the vehicle in the driving lane including this Can be estimated with high accuracy.

According to the second aspect of the present invention, a warning is appropriately given, so that the vehicle lane traveling support can be appropriately performed. Alternatively, the vehicle lane travel support by the steering control means can be performed smoothly.

  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. On the other hand, in addition to the steering torque sensor TS described above, the electronic control unit ECU2 includes 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 the yaw rate of the vehicle. A yaw rate sensor YS for detecting the rotation angle, a rotation angle sensor RS for detecting the rotation angle of the EPS motor, and the like are connected, and an EPS motor is connected to the output side. 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.

  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 is connected. 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. In addition, the detection state Rl is determined. This detection state Rl is a factor representing 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 driving lane is not detected is “0”. Accordingly, the configuration is such that the lateral position of the vehicle in the traveling lane is estimated only when the continuous line portion of the lane mark is detected, or as described later, the continuous line portion of the lane mark is detected. Only in some cases, the lateral position of the vehicle in the travel lane can be reflected in the estimation result. 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 vehicle model and road model using the detection signals of the yaw rate sensor YS and the steering angle sensor SS, the lane position y, The current vehicle state quantity X is estimated and calculated with the lane lateral movement speed dy (the lateral movement speed of the vehicle in the traveling lane and the time differential value of the lane position y), 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 can be expressed. Note that δf is a steering angle detected by the steering angle sensor SS, and ρ is a reciprocal of the 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 = [1000; 0100; 0010; 0001]

  On the other hand, based on the steering angle δf detected by the steering angle sensor SS and the vehicle body speed (vehicle speed) Vx detected by the vehicle body speed sensor VS, a target state quantity consisting of the following four factors in the target state quantity calculation unit M3. Is calculated. 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. Here, C is a conversion constant from the road curvature to the target yaw angle, and ρ is the reciprocal of the road curvature. Then, based on the vehicle body speed (vehicle speed) Vx and the reciprocal 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 M3 and the calculation result (current state quantity) of the state estimation calculation unit M2 is calculated, and based on this difference, the feedback control calculation unit A torque command value is calculated at M4. That is, in the feedback control calculation unit M4, the difference between the target value (added t) and the estimated value (added e) of the four factors representing the target state quantities are weighted by the gains K1 to K4. Is set as the target rotation angle (target steering angle) δ swt as follows.
δswt = K1 ・ (yt−ye) + K2 ・ (dyt−dye) + K3 ・ (ψt−ψe) + K4 ・ (γt−γe)

  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, the additional steering torque command value Tadd is Tadd = K0 · Calculated as (δswt−sw). The additional steering torque command value Tadd is transmitted to the steering control electronic control unit ECU2 (FIG. 2), and the electric power steering control unit M6 (FIG. 3) converts the torque command value Tadd into a normal power steering control amount. By adding, the electric power steering system EPS is controlled, and the correction steering according to the present invention is performed. Thus, since the lateral position of the vehicle in the traveling lane is reflected in the estimation result only when the continuous line portion of the lane mark is detected, the detection value when the continuous line portion of the lane mark is detected is used. Based on this, it is possible to appropriately estimate the lateral position of the vehicle in the traveling lane including the blank portion of the lane mark. Further, if necessary, the torque command value Tadd is supplied to the alarm output unit M6, 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 estimation calculation part M2) of the vehicle lateral position in a driving | running | working lane, without using torque command value Tadd.

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 control aspect in one Embodiment 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 and alarm means in one Embodiment of this invention.

Explanation of symbols

SW Steering wheel WH Wheel EPS Electric power steering system 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 (2)

A driving lane from an image obtained by continuously imaging a road surface by a steering control means that operates according to a steering wheel operation of a driver and can control a steering state according to a road surface driving state of the vehicle, and an imaging means for vehicle vicinity monitoring A vehicle lane detecting unit that detects the vehicle lane, and controls the steering control unit so that the vehicle travels in the vehicle lane detected by the vehicle lane detector, thereby assisting the vehicle in traveling in the vehicle lane. in lane running support system for a vehicle, having a road model in accordance with the vehicle motion model and the road curvature, in accordance with based rather state equation in said vehicle motion model and the road model, the travel lane detecting means detecting result of said vehicle Including the lateral position, lateral movement speed, yaw angle and yaw rate of the vehicle in the travel lane according to the steering state and the traveling state The vehicle state estimating means for estimating the state amount-out based on the detection value when the traveling lane detecting means detects the continuous line portion of the lane mark marking the traveling lane, a blank portion of the lane mark Only when the lateral position of the vehicle in the traveling lane is always estimated according to the state equation and the traveling lane detecting means detects a continuous line portion of the lane mark indicating the traveling lane. Vehicle state estimating means configured to reflect the lateral position of the vehicle in the estimation result, and target state quantity setting means for setting a target state quantity for the vehicle based on the steering state and the running state of the vehicle. And the vehicle state of the vehicle according to a comparison result between the target state quantity set by the target state quantity setting means and the state quantity estimated by the vehicle state estimation means. Lane running support system for a vehicle, characterized in that to support the travel of the inner.   Based on the estimation result of the lateral position of the vehicle in the travel lane by the vehicle state estimation means, at least warning means for warning a driver and correction steering means for correcting steering control by the steering control means, The vehicle lane travel support apparatus according to claim 1, further comprising one side.

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