JP6589658B2 - Travel control device - Google Patents

Description

  The present invention relates to a travel control device that provides a function of automatically driving a vehicle.

  Conventionally, a lane marking as a lane boundary can be obtained by analyzing an image captured by an in-vehicle camera that captures a surrounding area of the host vehicle (for example, in front of the vehicle) or by detecting reflected light from the lane marking by a laser radar. Is known, and based on the position of the lane marking in the photographed image, a technique for specifying the travel position in the lane in which the host vehicle is currently traveling (hereinafter, the host vehicle travel lane) is known.

  In addition, the information indicating the travel position in the travel lane of the vehicle thus identified is a process for assisting the steering operation of the driver, or the vehicle is automatically traveled (that is, automatically traveled) along a predetermined travel route. Used for processing. For example, Patent Document 1 discloses a technology for assisting a driver's steering operation so that the host vehicle travels in the vicinity of the center of the lane based on the position of a lane marking identified from a captured image of an in-vehicle camera.

JP 2007-334450 A

  In order to specify the travel position of the host vehicle in the host vehicle travel lane, the in-vehicle camera needs to be able to image a lane line (hereinafter referred to as a travel lane line) indicating the boundary of the host vehicle travel lane. However, the shape of the road is various, and it is not always possible to image a travel lane line while traveling.

  For example, when traveling on a curve, the travel lane marking provided on the inside of the curve tends to be out of the shooting range of the in-vehicle camera. In other words, when traveling on a curve, the amount of the traveling lane marking inside the curve reflected in the captured image of the in-vehicle camera is reduced compared to when traveling on a straight road. Such a tendency becomes stronger as the curvature radius of the curve is smaller. Furthermore, when the travel lane line provided on the inside of the curve is realized by discontinuously arranged objects such as broken lines and botsdots, the amount of the travel lane line reflected in the captured image of the in-vehicle camera is more It is further reduced.

  That is, during the curve traveling, the position of the traveling lane marking inside the curve (hereinafter, the inner lane marking) may not be recognized. Naturally, when the position of the inner lane marking is not recognized, it is difficult to perform support and travel control according to the travel position in the lane.

  Here, the problem to be solved by the present invention has been described by taking as an example the case where an in-vehicle camera is adopted as an apparatus for acquiring information for recognizing the position of a lane marking (hereinafter referred to as an imaging apparatus). Not exclusively. The imaging device may be a laser radar as described at the beginning of the background art. Even when a laser radar is employed as the imaging device, the same problem as in the case where the imaging device is an in-vehicle camera occurs.

  The present invention has been made based on this situation, and an object of the present invention is to provide a travel control device that can reduce the possibility that the travel lane line inside the curve cannot be recognized during curve travel. It is in.

A first invention for achieving the object is a road information acquisition unit (13) that is used in a vehicle and acquires front road information that is information indicating a structure of a road existing in front of the vehicle. An image acquisition unit (111) that acquires a captured image of an imaging device that captures a predetermined range and a current position of the vehicle based on a navigation signal transmitted by a navigation satellite included in the satellite navigation system , and a reception status of the navigation signal Based on the current position specifying unit (12) for determining whether or not the reliability of the position information indicating the current position is low, and the lane line recognition unit (112) for recognizing the position of the lane line in the captured image If, based on predetermined basic orbit determination techniques, in the straight road and the curve, run plan as a basic trajectory running track of the vehicle relative to the traveling lane mark is a division line indicating the boundary of the lane that the vehicle is traveling A trajectory planning unit (14), a vehicle control unit (15) for controlling the vehicle to travel along the travel trajectory planned by the travel trajectory planning unit, and a travel trajectory planned by the travel trajectory planning unit When the vehicle travels on a curve that exists in front of the vehicle, the image pickup amount that the image pickup device can pick up the inner lane marking that is the lane marking on the inner side of the curve is the position of the inner lane marking from the captured image by the lane line recognition unit. A recognition requirement determination unit (143) that determines whether or not the recognition requirement for recognizing the vehicle is satisfied based on the imaging parameter indicating the attachment position and imaging range of the imaging device in the vehicle and the road information ahead The recognition requirement determination unit determines whether or not the imaging amount in the curve satisfies the recognition requirement when the curve travels along the basic trajectory. Is on the curve If that captured amount is determined not to satisfy the recognition criteria, re-plan the inner maintain track is a track traveling curve inward from the base track, the division line recognition unit, during straight section running inside with a curve It is configured to identify the actual imaging amount that is the amount that can be imaged currently of the running lane line that becomes the lane line, and the vehicle control unit is determined to be in a state of low reliability by the current position specifying unit In addition, in the situation where the inner maintenance track is adopted as the traveling track on the curve, when it is detected that the actual imaging amount specified by the lane marking recognition unit starts to decrease, or becomes a predetermined threshold value or less. In this case, the driving position is configured to start to move toward the inside of the curve .
A second invention for achieving the above object is a road information acquisition unit (13) that is used in a vehicle and acquires front road information that is information indicating a structure of a road existing in front of the vehicle; An image acquisition unit (111) that acquires a captured image of an imaging device that captures a predetermined peripheral range, a current position specifying unit (12) that specifies the current position of the vehicle, and a partition that recognizes the position of the lane marking in the captured image Line recognition unit (112), traveling track planning unit (14) for planning a traveling track of a vehicle with respect to a traveling lane line that is a lane marking indicating the boundary of the lane in which the vehicle is traveling, and a traveling track planning unit When the vehicle control part (15) which performs control for a vehicle to drive | work along a running track and the curve which exists ahead of a vehicle runs along the running track planned by the running track plan part, an imaging device Is running inside the curve It is determined whether the imaging amount, which is the amount that can image the inner lane marking, which is the lane marking, satisfies the recognition requirement for the lane marking recognition unit to recognize the position of the inner lane marking from the captured image. A recognition requirement determination unit (143) that is determined based on an imaging parameter that indicates an attachment position and an imageable range and forward road information, and the recognition requirement determination unit has a curvature radius of a curve that is less than a predetermined threshold value And when the inner lane marking on the curve is not a solid line pattern, the recognition trajectory planning unit is configured to determine that the recognition requirement is not satisfied. When it determines with not satisfying, it is characterized by re-planning the driving | running track which changed the driving | running | working position with respect to a driving | running | working division line so that imaging amount may become large.
Furthermore, a third invention for achieving the above object includes a road information acquisition unit (13) that is used in a vehicle and acquires front road information that is information indicating a structure of a road existing in front of the vehicle; An image acquisition unit (111) that acquires a captured image of an imaging device that captures a predetermined peripheral range, a current position specifying unit (12) that specifies the current position of the vehicle, and a partition that recognizes the position of the lane marking in the captured image Line recognition unit (112), traveling track planning unit (14) for planning a traveling track of a vehicle with respect to a traveling lane line that is a lane marking indicating the boundary of the lane in which the vehicle is traveling, and a traveling track planning unit When the vehicle control part (15) which performs control for a vehicle to drive | work along a running track and the curve which exists ahead of a vehicle runs along the running track planned by the running track plan part, an imaging device Is inside the curve An imaging device in a vehicle determines whether or not the imaging amount, which is an amount that can image the inner lane line that is a row lane line, satisfies the recognition requirement for the lane line recognition unit to recognize the position of the inner lane line from the captured image. A recognition requirement determination unit (143) for determining based on the imaging parameter indicating the attachment position and the imageable range and the front road information, and the front road information is a lane in which the vehicle is currently traveling. Including information on whether there is an adjacent lane with the same direction as the traveling lane as the traveling direction, the traveling trajectory planning unit plans a traveling trajectory on a straight road and a curve as a basic trajectory based on a predetermined basic trajectory determination method. In addition, if the recognition requirement determination unit determines that the imaging amount in the curve does not satisfy the recognition requirement in the basic trajectory, it is a trajectory that travels inside the curve from the basic trajectory. It is configured to re-plan the maintenance trajectory, and the traveling trajectory planning unit is determined not to satisfy the recognition requirement even if the inner maintenance trajectory is adopted by the recognition requirement determination unit, and in the curve When there is an adjacent lane in a direction that is on the outside of the curve, it is configured to plan a traveling track that changes lanes before entering the curve to the adjacent lane.

  In the above configuration, the recognition requirement determination unit determines that the imaging amount of the inner lane marking during curve driving does not satisfy the recognition requirement for the lane marking recognition unit to recognize the position of the inner lane marking from the captured image of the camera. In such a case, the traveling trajectory planning unit corrects the traveling trajectory on the curve so that the imaging amount of the inner lane marking is increased. According to such a configuration, it is possible to increase the amount by which the inner lane marking can be imaged during curve traveling. As a result, it is possible to reduce the possibility that the running lane marking inside the curve cannot be recognized during the curve running.

  In addition, the code | symbol in the parenthesis described in the claim shows the correspondence with the specific means as described in embodiment mentioned later as one aspect, Comprising: The technical scope of this invention is limited is not.

1 is a block diagram illustrating a schematic configuration of a travel control system 100. FIG. It is a conceptual diagram which shows an example of the implementation | achievement aspect of the lane marking which shows the boundary of a lane. It is a conceptual diagram which shows an example of the implementation | achievement aspect of the lane marking which shows the boundary of a lane. It is a flowchart corresponding to traveling track planning processing. It is a continuation of the flowchart shown in FIG. It is a conceptual diagram showing the action | operation of a conventional structure. It is a figure for demonstrating the action | operation and effect of this embodiment. It is a figure for demonstrating the action | operation and effect of this embodiment. It is a figure for demonstrating the action | operation of the modification 1. FIG. It is a conceptual diagram showing an example of the running track defined by embodiment. 12 is a flowchart for explaining a procedure of processing executed by a travel control ECU 1 of a third modification. It is a figure for demonstrating the action | operation and effect of the modification 3. It is a block diagram which shows the structure of the traveling control system 100 in the modification 7. FIG. It is a figure for demonstrating the action | operation and effect of traveling control ECU1 in the modification 7. FIG.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a diagram illustrating an example of a schematic configuration of a travel control system 100 to which a travel control device according to the present invention is applied. The travel control system 100 is mounted on a vehicle and includes a travel control ECU 1, an in-vehicle camera 2, a GNSS receiver 3, a map data storage unit 4, a steering ECU 5, a power control ECU 6, and a brake ECU 7, as shown in FIG. . The traveling control ECU 1 corresponds to the traveling control device described in the claims. For convenience, the vehicle on which the traveling control system 100 is mounted will be hereinafter referred to as the own vehicle.

<Overall configuration>
The travel control ECU 1 is connected to each of the in-vehicle camera 2, the GNSS receiver 3, the map data storage unit 4, the steering ECU 5, the power control ECU 6, and the brake ECU 7 so as to be able to communicate with each other. The travel control ECU 1 is an ECU (Electronic Control Unit) that automatically controls the speed and steering angle of the host vehicle based on signals input from each member connected to itself. That is, the travel control ECU 1 provides an automatic travel function. For example, the traveling control ECU 1 controls the steering angle of the own vehicle in cooperation with the steering ECU 5, accelerates the own vehicle in cooperation with the power control ECU 6, or cooperates with the brake ECU 7 in the vehicle speed of the own vehicle. Slow down.

  The travel control ECU 1 is configured as a normal computer, and includes a CPU, a RAM, a flash memory, a ROM, an I / O, and a bus line that connects these configurations. The flash memory stores a program for causing a normal computer to function as the travel control ECU 1 (hereinafter referred to as a travel control program), camera parameters described later, and the like. Details of functions provided by the travel control ECU 1 will be described later.

  The in-vehicle camera 2 is an optical camera, and for example, a CMOS camera or a CCD camera can be used. The in-vehicle camera 2 is installed, for example, at the upper end of the windshield so as to capture a predetermined range in front of the host vehicle. Image data captured by the in-vehicle camera 2 is sequentially provided to the travel control ECU 1. As another aspect, the in-vehicle camera 2 may be an infrared camera, a near infrared camera, or the like. Furthermore, the in-vehicle camera 2 may be a stereo camera.

  Data such as the installation position, mounting orientation, imaging angle of view, lens distortion coefficient, focal length, pixel size, and pixel ratio of the in-vehicle camera 2 in the host vehicle are registered in the flash memory as the camera parameters described above. In addition, among the imaging field angles, an angle of view (hereinafter referred to as an effective field angle) that can be used for the process of recognizing the lane marking described later is also registered as a camera parameter.

  The installation position of the in-vehicle camera 2 may be represented by a position in the vehicle width direction with respect to a predetermined reference point of the vehicle, a position in the front-rear direction, a position in the height direction, and the like. The mounting posture of the in-vehicle camera 2 is represented by, for example, the angles (that is, the roll angle, the pitch angle, and the yaw angle) formed by the optical axis of the in-vehicle camera 2 with respect to the vehicle longitudinal direction, the vehicle width direction, and the vertical direction. Just do it.

  Note that the camera parameters do not have to include all the information described above. It is only necessary to include at least the installation position and the mounting orientation (so-called 6-degree-of-freedom value in which the installation position and orientation are uniquely determined) and the effective angle of view.

  The GNSS receiver 3 receives a navigation signal transmitted from a navigation satellite provided in a GNSS (Global Navigation Satellite System) which is a satellite navigation system, and sequentially calculates a current position based on the received navigation signal. The position information indicating the current position may be represented by, for example, latitude, longitude, and altitude. The current position may be expressed using a predetermined coordinate system. The position information indicating the current position calculated by the GNSS receiver 3 is sequentially provided to the travel control ECU 1.

  The map data storage unit 4 stores road map data indicating road connection relationships, road shapes (in other words, road structures), and the like. The map data storage unit 4 may be realized by a hard disk drive or a memory card. As another embodiment, the map data storage unit 4 may be a database provided in a center provided outside the vehicle. In this case, it is assumed that the travel control ECU 1 is configured to be able to access a database as the map data storage unit 4 via a wide area communication network.

  The road map data includes node data for each node and link data for each link. A node is a point that is set as appropriate for representing the connection relationship of roads, such as a point where a plurality of roads intersect, merge, and branch, and a link is a road that connects nodes.

  The node data includes a node ID, a node coordinate, a node name, a node type, a connection link ID in which link IDs of all links connected to the node are described, a connection angle between connection links, and the like.

  The link data includes a link ID, a link length, a link shape, node coordinates (latitude / longitude) between the start and end of the link, road width, lane information, speed limit, and the like. The lane information includes lane line information indicating information on the number of lanes included in the link, the lane width (hereinafter, lane width), and lane lines for each lane.

  The lane marking here refers to a line or a point sequence arranged on a road for indicating a lane boundary, such as a white line, a yellow line, or a botsdot. The lane marking information represents in what manner the lane marking is realized. As an implementation mode, there are a pattern realized by a yellow or white solid line (hereinafter, a solid line pattern), a pattern realized by a white broken line (hereinafter, a dashed line pattern), a botsdot, a cat's eye, and the like. The lane line information includes information about each lane line on the right side and the left side in the traveling direction of the lane.

  In the present embodiment, as a more preferable aspect, when the lane marking is realized by a broken line pattern or a discontinuous pattern such as botsdots as shown in FIG. 2 or FIG. It is assumed that an interval (hereinafter, clearance) L1 in which elements are arranged along the traveling direction is provided as lane marking information. In addition, when the lane marking is realized in a broken line pattern, the length (hereinafter referred to as paint length) L2 of the portion to which the painting is applied is also included in the lane marking information. Of course, providing these pieces of information as map data is a more preferable aspect and is not essential. The broken line in FIG. 2, FIG. 3 represents the boundary of the lane, and the arrow represents the advancing direction of the lane. A lane refers to a strip-shaped roadway section that is partitioned by a lane marking.

  The steering ECU 5 is an ECU that controls the steering angle of the host vehicle by controlling the steering actuator that rotates the steering shaft. When the steering instruction is received from the travel control ECU 1, the steering ECU 5 determines the steering angle based on the steering instruction. Change.

  The power control ECU 6 is an ECU that controls the power generated by the power source of the host vehicle. There are an engine and a motor as a power source. When an acceleration instruction is received from the travel control ECU 1, the power control ECU 6 increases the power generated by the power source to accelerate the host vehicle. The brake ECU 7 is an ECU that controls the brake actuator, and when receiving a deceleration instruction from the travel control ECU 1, the brake ECU 7 decelerates the host vehicle based on the deceleration instruction.

  In the present embodiment, as an example, the travel control ECU 1 controls the mechanical system such as the steering actuator via another ECU such as the steering ECU 5, but is not limited thereto. As another aspect, the traveling control ECU 1 may directly control the mechanical system.

<About the function of the traveling control ECU 1>
Next, functions provided in the travel control ECU 1 will be described. The travel control ECU 1 includes an image processing unit 11, a current position specifying unit 12, a road information acquisition unit 13, a travel trajectory planning unit 14, and vehicle control as functional blocks realized by the CPU executing the above travel control program. The unit 15 is provided. The image processing unit 11 includes an image acquisition unit 111 and a lane marking recognition unit 112 as finer functional blocks. The traveling trajectory planning unit 14 includes a basic trajectory planning unit 141, an imaging amount prediction unit 142, a recognition requirement determination unit 143, and a trajectory correction unit 144 as finer functional blocks.

  Note that some or all of the functional blocks included in the travel control ECU 1 may be realized in hardware by one or a plurality of ICs. Further, it may be realized by a combination of execution of software by the CPU and hardware members.

  The image acquisition unit 111 sequentially acquires image data captured by the in-vehicle camera 2. The lane marking recognition unit 112 detects (in other words, recognizes) a portion of the captured image that is capturing the lane marking by analyzing the image data acquired by the image acquisition unit 111. That is, the detection of the lane marking in the captured image can be realized using a known method such as an analysis method using an active contour model or an analysis method using Hough transform.

  Then, the lane line recognition unit 112 identifies the position of the lane line relative to the own vehicle based on the position of the lane line in the image and the camera parameter, and recognizes the travel position, posture, etc. of the own vehicle relative to the lane line. . In addition, in order for the lane marking recognition unit 112 to recognize the position of the lane marking, recognition requirements described later need to be satisfied.

  The travel position here is the position of the host vehicle in the vehicle width direction within the lane, and represents the distance from each of the right lane line and the left lane line. The process of specifying the travel position based on the position of the lane marking in the image and the camera parameter may be performed using a known method. In the following, for convenience, of the various lane markings provided on the road, the lane marking indicating the boundary of the traveling lane is also referred to as a traveling lane marking. The travel position specified by the lane marking recognition unit 112 is sequentially provided to the travel trajectory planning unit.

  The current position specifying unit 12 specifies the current position of the host vehicle based on the positioning result obtained by the GNSS receiver 3. The current position specifying unit 12 specifies the traveling lane based on the specified current position and the map data stored in the map data storage unit 4.

  The current position specifying unit 12 corrects the detection result of the GNSS receiver 3 by using detection values of a gyro sensor (not shown) or an acceleration sensor (not shown) mounted on the host vehicle, thereby using the current position and the travel time. A lane may be specified. Furthermore, you may identify a present position and a travel lane by implementing a map matching process using the road map data which the road information acquisition part 13 mentioned later acquires.

  In the map matching process, a vehicle travel locus is obtained from the traveling direction, vehicle speed, and position information of the vehicle at a plurality of time points, and the current position of the vehicle is specified by comparing the vehicle travel locus with the road shape obtained from the map information. It is processing. Since the map matching process is a well-known technique, a detailed description thereof is omitted here.

  In addition to the positioning result of the GNSS receiver 3, the current position specifying unit 12 cooperates with the image processing unit 11 to specify the current position and traveling lane of the host vehicle based on the captured image of the in-vehicle camera 2. May be.

  The road information acquisition unit 13 acquires information (hereinafter, forward road information) indicating the structure of a road existing ahead of the host vehicle (in other words, the traveling direction). The forward road information here includes the width of the lane in which the host vehicle is traveling (hereinafter referred to as the traveling lane), the shape of the traveling lane within a predetermined distance from the current position, and the lane marking information of the traveling lane and the adjacent lane. included. The shape of the traveling lane includes a radius of curvature.

  In the present embodiment, as an example, the road information acquisition unit 13 acquires link data and node data corresponding to a road on which the host vehicle will travel from now on as front road information. Specifically, data of a link on which the host vehicle currently determined from the current position specified by the current position specifying unit 12 and a link connected to the link along the road are acquired.

  That is, the road information acquisition unit 13 reads the map data around the current position specified by the current position specifying unit 12 from the map data storage unit 4. This is because the link data includes road shape and lane information. The road information acquisition unit 13 may identify a road (in other words, link data to be read) on which the host vehicle will travel by referring to information indicating a travel route to the destination.

  Moreover, although it is set as the aspect which acquires front road information from the map data storage part 4 in this embodiment, it is not restricted to this. The road information may be acquired by the image processing unit 11 analyzing the image captured by the in-vehicle camera 2. In that case, the image processing unit 11 functions as the road information acquisition unit 13. Furthermore, the traveling control ECU 1 may acquire the road information ahead by using the map data and the environment recognition based on the captured image of the in-vehicle camera. For example, the lane marking information may be specified by analyzing a captured image of the in-vehicle camera.

  The traveling track planning unit 14 plans the traveling track of the host vehicle based on the forward road information acquired by the road information acquiring unit 13. The travel trajectory here represents which position travels with respect to the lane marking on the road. When it is determined that the lane change to the other lane is necessary as well as the travel position in the current travel lane, the travel path planning unit 14 determines the lane change point or the lane to which the lane is changed. The travel position etc. are also planned. The basic trajectory planning unit 141, the imaging amount prediction unit 142, the recognition requirement determination unit 143, and the trajectory correction unit 144 included in the travel trajectory planning unit 14 will be referred to separately in the description of the read plan related process.

  The vehicle control unit 15 outputs an instruction to the steering ECU 5, the power control ECU 6, and the brake ECU 7 so that the host vehicle travels along the traveling track planned by the traveling track planning unit 14.

  The traveling control ECU 1 provides the automatic traveling function described above by the cooperation of the various functional blocks described above. The travel control ECU 1 includes a standard control mode and a single lane marking reference mode as automatic travel modes. The standard control mode is an operation mode in a state where the lane marking recognition unit 112 can recognize the lane markings on both sides of the host vehicle, and based on the positions of the lane markings on both sides, the posture and the driving position of the host vehicle in the driving lane And various control target amounts are determined.

  The single lane marking reference mode is an operation mode in a state where the lane marking recognition unit 112 cannot recognize the lane marking on one side of the host vehicle. In the single lane marking reference mode, the posture and travel position of the host vehicle are specified based on the position of the recognized lane marking, and various control target amounts are determined. Here, the single lane line reference mode for specifying the posture and the traveling position of the host vehicle with reference to the lane marking outside the curve during the curve traveling is also referred to as an outline line reference mode. The curve here refers to a section where the radius of curvature R is less than a predetermined threshold.

<Travel track planning process>
Next, a series of processing (hereinafter referred to as travel trajectory planning processing) executed by the travel control ECU 1 to plan a travel trajectory will be described using the flowcharts shown in FIGS. 4 and 5. This traveling track planning process may be started periodically at a predetermined cycle.

  First, in step S1, the image acquisition unit 111 acquires a captured image of the in-vehicle camera 2, and proceeds to step S2. In step S2, the current position specifying unit 12 specifies the current position of the host vehicle based on the positioning result of the GNSS receiver 3, and proceeds to step S3. In addition, the road information acquisition part 13 acquires front road information with step S2. In step S3, the current position specifying unit 12 specifies the traveling lane based on the current position specified in the previous step S2, and proceeds to step S4.

  In step S4, the basic trajectory planning unit 141 plans the travel trajectory of the host vehicle based on a preset basic trajectory determination method based on the current position of the host vehicle, the travel lane, and the road information ahead, and proceeds to step S5. . For example, the basic trajectory planning unit 141 uses a central portion in the width direction of the traveling lane (hereinafter, the lane central portion) in a straight section (that is, a straight road) that is a section in which the curvature radius R is equal to or greater than a predetermined threshold. Plan the travel path to travel. Also, on the curve, an out-in-out type track is planned so that the radius of curvature R of the traveling track is maximized in the same lane. In other words, at the start and exit points of the curve, the travel position is moved outside the center of the lane, and near the middle point between the start and exit points of the curve, the travel position is located inside the curve from the center of the lane. Plan the trajectory near the lane line. Thereby, the centrifugal force which acts on a passenger | crew or a vehicle body is suppressed, and stability of vehicle travel is improved.

  The basic trajectory planning unit 141 also sets the travel position outside the curve so as to smoothly connect to the travel trajectory on the curve from a point that is a predetermined distance before the start of the curve even in the straight section. Plan a running track that moves at a width-shifting ratio. A track that gradually approaches the center of the lane from the outside of the curve at a predetermined width-shifting ratio from the point where the curve ends is planned. The width adjustment ratio represents the ratio of the travel distance in the vehicle width direction to the travel distance in the traveling direction, and a specific value may be designed as appropriate.

  The basic trajectory planning unit 141 plans the travel trajectory so that the travel position is more than the minimum margin from the lane line when the travel position on the curve is set closer to the outer lane line or closer to the inner lane line. The minimum margin may be appropriately designed as a parameter for the vehicle to travel safely.

  In addition, what is necessary is just to specify the curvature radius R of the traveling lane used when planning a traveling track | truck by analyzing the road shape shown by front road information. The threshold value for separating the straight section and the curve may be designed as appropriate, for example, 500 meters. A known method may be used as a method for specifying the curvature radius R from the road shape.

  In addition, the range in which the basic trajectory planning unit 141 plans the travel trajectory (hereinafter referred to as the trajectory plan range) may be designed as appropriate. For example, the track planning range may be a fixed distance or a length corresponding to the traveling speed of the host vehicle. When the track plan range is set to a length corresponding to the traveling speed of the host vehicle, the longer the traveling speed, the longer it may be. In the present embodiment, as an example, the basic trajectory planning unit 141 plans a travel trajectory for a road section that passes within one minute from the present time. Of course, the trajectory planning range may be designed as appropriate, and the trajectory planning range may be up to the destination.

  In step S <b> 5, the imaging amount prediction unit 142 determines whether there is a curve ahead of the host vehicle based on the front road information acquired by the road information acquisition unit 13. The range pointed to by the front of the host vehicle here may be appropriately designed, for example, about 500 meters. Further, the length may correspond to the traveling speed of the host vehicle.

  If there is a curve ahead of the host vehicle, an affirmative determination is made in step S5 and the process proceeds to step S6. On the other hand, if there is no curve ahead of the host vehicle, a negative determination is made in step S5, and this flow ends. When there is no curve ahead of the host vehicle, the vehicle control unit 15 performs control so that the host vehicle travels along the traveling track planned by the basic track planning unit 141.

  In step S <b> 6, the imaging amount prediction unit 142 predicts an imaging amount that is the amount of lane markings inside the curve that can be captured by the in-vehicle camera 2 during the forward curve traveling detected in step S <b> 2. Hereinafter, the lane marking inside the curve is also simply referred to as the inner lane marking.

  The prediction of the imaging amount may be performed for each point at a fixed distance on the traveling track, or may be performed only at a point that satisfies a preset condition where the imaging amount is assumed to be reduced. . The point where the imaging amount is assumed to be reduced is a point where the traveling track on the curve is outside the center of the lane, or the optical axis direction of the in-vehicle camera 2 with respect to the tangential direction of the inner lane marking. Should be the point facing the outside of the curve.

  The imaging amount at a certain point on the traveling track may be calculated based on the camera parameters, the lane width W, and the curvature radius R. Specifically, the length of the inner lane line that falls within the effective imaging range of the in-vehicle camera 2 based on the lane width W, the radius of curvature R, and the travel position at that point (in other words, the distance from the inner lane line). (That is, the imaging amount) is specified.

  The effective imaging range here is an imaging range of a road surface corresponding to an effective angle of view, and is determined by camera parameters. The imaging amount may be the length of the road surface area functioning as a lane marking including the clearance area as well as the area where the lane marking is present (paint portion or bots dot). Of course, the imaging amount prediction unit 142 can acquire the lane marking information of the inner lane line as the front road information, and if the inner lane line is realized by a broken line pattern, a botsdot, or the like, It is preferable to specify the imaging amount using the clearance L1 and the paint length L2. In the following description, a road surface area that functions as a lane marking including a clearance portion, in other words, an area where an actual member that indicates the lane marking can exist is also referred to as a lane marking presence area.

  In step S7, the recognition requirement determination unit 143 recognizes that the imaging amount of the inner lane marking during curve traveling predicted by the imaging amount prediction unit 142 is a requirement for the lane marking recognition unit 112 to recognize the position of the lane marking. Determine whether the requirements are met. Here, as an example, it is determined that the recognition requirement is not satisfied when the time during which the state in which the imaging amount is equal to or less than the predetermined detection necessary amount (hereinafter referred to as “lost lost time”) is equal to or longer than the predetermined lost allowable time.

  The necessary detection amount is the length of the lane marking in the image necessary for the lane marking recognition unit 112 to detect the lane marking from the captured image. A state in which the amount of imaging is equal to or less than a predetermined detection required amount (hereinafter referred to as a lost state) means that the length of the lane markings included in the captured image is too short or is not included in the captured image in the first place. This is equivalent to a state in which the lane markings cannot be detected from the captured image. The required amount of detection is determined by an image recognition processing algorithm or the like. The recognition requirement determination unit 143 calculates a lost duration by identifying a section in which the imaging amount is continuously equal to or less than a predetermined detection necessary amount during curve traveling, and dividing by the planned speed when traveling in the section. To do.

  The lost allowable time is an upper limit value of the time that allows the lost state to continue. The lost allowable time is also a value determined by an image recognition algorithm or the like, and may be appropriately designed. The reason for including the lost duration as a recognition requirement is that even if the lane line deviates from the effective imaging range of the in-vehicle camera 2 instantaneously, the location of the lane line can be recognized if the lane line can be captured again within a certain time. This is because there is a high possibility (or a predetermined recognition accuracy can be guaranteed).

  If the recognition requirement determination unit 143 determines in step S7 that the recognition requirement is not satisfied while traveling on a curve, a negative determination is made in step S7, and the process proceeds to step S8. On the other hand, if it is determined that the recognition requirement is satisfied, an affirmative determination is made in step S7, and this flow ends.

  If it is determined that the recognition requirement is satisfied, the travel trajectory planned by the basic trajectory planning unit 141 is adopted as the actual travel trajectory, and the travel trajectory on the curve ahead is a trajectory according to the out-in-out method. .

In step S8, the trajectory correcting unit 144 performs a series of traveling trajectories on the curve planned by the basic trajectory planning unit 141 on the inner side of the curve from the center of the lane and the margin with the inner lane marking is a predetermined value. (hereinafter, the inner side maintain track) proceeds to step S9 and correct to. The margin with the inner lane marking is determined from the effective angle of view of the in-vehicle camera 2 and the detection required dose. The margin with the inner partition line is set to be equal to or larger than a preset minimum margin. In the present embodiment, as an example, the trajectory correcting unit 144 plans a trajectory in which the margin with the inner marking line is the minimum margin value as the inner maintenance trajectory. Of course, the margin with the inner partition line for forming the inner maintenance track may be appropriately designed in a range that is equal to or larger than the minimum margin.

  In step S9, the imaging amount prediction unit 142 predicts the imaging amount of the inner lane marking in the curve when the traveling track corrected by the track correction unit 144 is adopted, and proceeds to step S10. The prediction method is the same as in step S6.

  In step S10, whether or not the recognition requirement determination unit 143 satisfies the recognition requirement for the inner lane marking during curve driving based on the imaging amount of the inner lane marking predicted in the previous step S9, as in step S7. Determine whether or not. If it is determined that the recognition requirement for the inner lane marking is not satisfied, a negative determination is made in step S10 and the process proceeds to step S11. On the other hand, when it determines with recognition requirements being satisfied, step S10 is affirmed and this flow is complete | finished.

  When it is determined in step S10 that the recognition requirement is satisfied, the vehicle control unit 15 adopts the traveling track obtained by the correction by the track correcting unit 144 as the actual traveling track. In other words, the travel trajectory from the start point of the curve ahead to the exit point is a trajectory that is closer to the inside of the curve than the center of the lane in the current travel lane.

  In step S11, the trajectory correcting unit 144 is based on the forward road information acquired by the road information acquiring unit 13, and is adjacent to the direction in which the traveling lane is the same direction as the traveling lane in the direction that is inside the curve as viewed from the current traveling lane. It is determined whether or not there is a lane (hereinafter referred to as an inner adjacent lane). If there is an inside adjacent lane, an affirmative determination is made in step S11 and the process proceeds to step S12. On the other hand, if there is no inner adjacent lane, a negative determination is made in step S12 and the process proceeds to step S16.

  In step S12, the imaging amount prediction unit 142 predicts the imaging amount of the inner lane marking on the forward curve when the lane is changed to the inner lane. Here, the inner lane marking to be predicted is an inner lane marking for the inner adjacent lane.

  The imaging amount of the inner lane marking at the lane change destination may be predicted assuming that the traveling position on the curve at the lane change destination is maintained at the center of the lane. Of course, as another aspect, the imaging amount of the inner lane marking may be predicted using the traveling track on the curve after the lane change as an out-in-out track or an inner maintenance track.

  In step S13, based on the prediction result in the previous step S12, it is determined whether the recognition requirement for the inner lane line is satisfied by changing the lane to one inner lane. If the recognition requirement is satisfied, an affirmative determination is made in step S13 and the process proceeds to step S14. On the other hand, if the recognition requirement is not satisfied, a negative determination is made in step S13 and the process returns to step S11. If the determination in step S13 is negative and the process returns to step S11, steps S11 to S13 are performed for a lane one curve inside the lane that has been assumed as the lane change destination.

  In step S14, it is determined to change the lane to the lane in which the determination result that the recognition requirement is satisfied in step S13 is obtained, and the process proceeds to step S15. In step S15, the trajectory correction unit 144 plans a travel trajectory that incorporates a lane change to the lane determined in the previous step S14 before entering the curve, and ends this flow.

  In step S16, it is determined whether or not it is possible to shift to the contour line reference mode in which the vehicle control is performed only on the outer lane line (hereinafter, contour line) of the current travel lane. Satisfy the requirements (hereinafter referred to as mode transition requirements) required to implement the contour line reference mode based on the amount of image of the contour line at the predicted curve, the legal speed of the road, and the speed and position of the vehicle before and after the host vehicle. If not, it is determined that the transition to the outline reference mode cannot be made, and the process proceeds to step S18. On the other hand, when the imaging amount of the contour line in the curve satisfies the mode transition requirement, it is determined that the contour line reference mode can be transitioned to, and the process proceeds to step S17. The mode transition requirement is a requirement for guaranteeing that the recognition accuracy of the posture of the host vehicle (including the travel position) with respect to the travel lane is sufficient for carrying out the automatic travel. The specific contents of the mode transition requirement may be appropriately designed.

  In step S17, it shifts to the outline reference mode and ends this flow. In step S18, it is decided to transfer the authority of driving operation to the driver, and this flow is finished. Note that the authority transfer to the driver may be executed when an operation indicating that the driver receives the authority of the driving operation is performed.

<Summary of Embodiment>
Next, the operation and effect of the present embodiment described above will be described by introducing a comparative configuration. Here, the comparative configuration is a configuration in which only the out-in-out method is adopted as a traveling track on a curve. In such a comparison configuration, depending on the curvature radius R of the curve and the lane width W as described above, the inner lane marking may not be recognized. As a result, the recognition accuracy of the posture of the host vehicle with respect to the traveling lane may be reduced, and automatic traveling may not be continued. This is because in order to perform automatic traveling, the recognition accuracy of the posture of the host vehicle with respect to the traveling lane needs to be equal to or greater than a predetermined threshold.

  In particular, since the lane marking itself is curved in the curve, it is difficult to accurately recognize the posture of the host vehicle with respect to the lane based on the lane marking only on one side. For this reason, even if automatic driving is continued using only the contour line as a guideline, the recognition accuracy of the posture and driving position of the host vehicle on the lane deteriorates and unnatural acceleration in the vehicle width direction (so-called lateral G). May occur.

  In the comparative configuration, the points where the imaging amount of the inner lane marking is difficult to satisfy the recognition requirement are, for example, a point P1 for entering the curve, a point P2 for exiting, etc. as shown in FIG. In the vicinity of the point P1 or the exit point P2 that enters the curve, the traveling position is closer to the outer side of the curve, or the optical axis of the in-vehicle camera 2 faces the outer side of the curve with respect to the tangential direction of the inner dividing line. This is because the line tends to be outside the effective imaging range.

  On the other hand, in the configuration of the present embodiment, when it is predicted that the imaging amount of the inner lane marking will not satisfy the recognition requirement in the out-in-out traveling track (NO in step S7), a curve as shown in FIG. Re-plan the series of running tracks at the inner maintenance track. In addition, Q1 and Q2 in FIG. 7 represent points corresponding to P1 and P2 in FIG. By adopting the inner maintenance trajectory, the possibility that the inner lane marking is outside the effective imaging range can be suppressed, and the possibility that the imaging amount of the inner lane marking satisfies the recognition requirement can be increased. As a result, it is possible to reduce the possibility that the automatic traveling cannot be continued or the unnatural side G is generated during the curve traveling.

  Further, in the above-described embodiment, when it is determined that the inner lane marking cannot be sufficiently imaged only by adjusting the travel position within the current travel lane (NO in step S10), steps S11 to S14 are performed. Thus, the traveling track for changing the lane to the adjacent lane on the inner side of the curve where the determination result that the recognition requirement is satisfied is obtained is planned. According to such an aspect, the possibility of traveling on a curve can be further increased while maintaining a state in which the inner lane marking can be recognized.

  By the way, the curvature radius R becomes smaller as the lane is inside the curve as shown in FIG. Therefore, if the inner lane marking in the inner adjacent lane is a broken line pattern, the imaging amount is less likely to satisfy the recognition requirement even if the lane is changed from the current travel lane to the inner adjacent lane. In other words, when the lane change to the lane on the inside of the curve changes the imaging amount of the inner lane line to meet the recognition requirement, the inner lane line of the lane that is the lane change destination is provided in a solid line pattern It is the case. This is because, when the inner partition line is a solid line pattern, it is possible to expect an increase in the imaging amount without causing a reduction in the imaging amount derived from the clearance portion.

  FIG. 8 shows a situation where the host vehicle is traveling on the lane Ln1 on the outer side of the curve in a curve on one lane with two lanes Ln1 and Ln2 having the same direction as the traveling direction. In the drawing, R1 represents the radius of curvature R of the lane Ln1, and R2 represents the radius of curvature R of the lane Ln2. The inner lane line of the lane Ln1 is provided in a broken line pattern, and the inner lane line of the lane Ln2 is provided in a solid line pattern.

  In view of such an operation, the series of processing from step S11 to step S14 in the present embodiment may correspond to processing for determining that the inner lane marking is to be changed to a lane provided in a solid line pattern. That is, in the above-described embodiment, when it is determined that the inner lane marking cannot be sufficiently imaged only by adjusting the traveling position in the current lane (NO in step S10), the adjacent lane having the inner lane marking of the solid line pattern. A mode of planning a traveling track for changing lanes is disclosed.

  In the above-described embodiment, when the imaging amount when the lane is changed to the inner adjacent lane is predicted and it is determined that the recognition requirement can be satisfied by changing the lane to the inner adjacent lane, the lane is changed to the lane. Although the aspect which plans the running track to perform was illustrated, it is not restricted to this. As another aspect, for example, the processing of steps S12 to S13 is performed when it is determined whether or not the inner lane marking of the adjacent lane as the lane change destination candidate is provided in a solid line pattern, and provided in the solid line pattern. It is good also as a process which determines changing a lane to the said adjacent lane. Even in such an aspect, when it is determined that the inner lane line cannot be sufficiently imaged only by adjusting the traveling position within the current lane (NO in step S10), the adjacent lane having the inner lane line of the solid line pattern is changed. It is possible to plan a running track to change lanes.

  As mentioned above, although an example of embodiment of this invention was demonstrated, this invention is not limited to the above-mentioned embodiment, The various modifications described below are also contained in the technical scope of this invention. Of course, the various variations described below can be combined with one or more other variations described below. In addition to the following, various modifications can be made without departing from the scope of the invention.

  In addition, about the member which has the same function as the member described in the above-mentioned embodiment, the same code | symbol is attached | subjected and the description is abbreviate | omitted. In addition, when only a part of the configuration is mentioned, the configuration of the above-described embodiment can be applied to the other portions.

[Modification 1]
In the above-described embodiment, as a measure for maintaining a state in which the imaging amount of the inner lane marking satisfies the recognition requirement (hereinafter, recognition state), in addition to adopting the inner maintenance track, changing the lane to the lane inside the curve However, the present invention is not limited to this. When it is determined that the recognition requirement cannot be satisfied even if the inner maintenance track is employed, the process after step S16 may be performed. In other words, it is not essential to consider changing the lane to the lane inside the curve.

[Modification 2]
Further, as a measure for maintaining the recognition state on the curve, as shown in FIG. 9, it may be possible to select to change the lane to the lane outside the curve. This is because, if the lane is changed to the lane outside the curve, the radius of curvature R increases, and the possibility that the inner lane marking can be captured in the effective imaging range increases.

  For example, when it is determined in step S10 that the recognition state cannot be maintained even if the inner maintenance track is adopted in the current traveling lane, the inner lane marking on the forward curve when the lane is changed to one adjacent adjacent lane The imaging amount of is predicted.

  In addition, what is necessary is just to estimate the imaging amount in a lane change destination, for example as the driving | running | working position in the curve in a lane change destination maintains the lane center part. Then, if it is determined that the recognition state in the curve can be maintained by changing the lane to the adjacent lane outside the curve, it may be determined to change the lane to the adjacent lane. Of course, the second modification can be combined with the above-described embodiment and the first modification.

  In addition, according to the above, as a measure for maintaining the recognition state on the curve (hereinafter referred to as the recognition state maintenance measure), the correction of the traveling track in the current traveling lane, the lane change to the adjacent lane inside the curve, A lane change to the adjacent lane outside the curve is proposed. The priority order for examining various recognition state maintenance policies may be designed as appropriate.

  For example, the recognition requirements are set in the following order: correction of the traveling track in the current lane, change of lane to the inner lane, change of lane to the outer lane, change of lane to the inner lane It may be determined whether or not it can be satisfied. The priorities for the various recognition state maintenance policies are preferably set such that the number of lane changes required to maintain the recognition requirements on the curve is reduced.

  In addition, if the configuration is such that both the lane change to the one adjacent lane and the lane change to the one adjacent lane can be adopted as the recognition state maintenance measures, which one is adopted As an aspect in which the imaging amount prediction unit 142 predicts whether or not the imaging amount of the inner lane marking will increase, and the traveling trajectory planning unit 14 plans a traveling trajectory for changing the lane to the lane with the larger imaging amount predicted. Also good.

[Modification 3]
The recognition requirements are satisfied in the second curve of the traveling track from the first curve (hereinafter referred to as the first curve) from which the host vehicle will travel to the next curve (hereinafter referred to as the second curve). It is preferable to plan in consideration of whether or not. For example, as shown in FIG. 10, the use of the inner maintenance track as the running track of the second curve may cause unnecessary lateral G between the first curve and the second curve.

  Specifically, it is as follows. FIG. 10 shows an example in which the first curve C1 and the second curve C2 have a connection structure that can generate an unnecessary lateral G. FIG. In FIG. 10, the first curve C <b> 1 and the second curve C <b> 2 are close to each other, and the respective turning directions are reversed left and right. Further, the curvature radius R of the first curve C1 is sufficiently large so that the recognition state can be continued, whereas the curvature radius R of the second curve C2 is a value that is so small that the recognition state cannot be continued. St in the figure represents a straight section connecting the first curve C1 and the second curve C2.

  In the case of such a road structure, the traveling trajectory planning unit 14 plans an out-in-out traveling trajectory for the first curve C1, so that the host vehicle follows the traveling trajectory according to the first curve. Driving C1 out-in-out and exiting the first curve C1, the host vehicle starts from the right side of the lane toward the center of the lane. However, since the traveling track planning unit 14 plans the inner maintenance track with respect to the second curve C2, the vehicle control unit 15 is in the middle of returning to the center of the lane, or a predetermined time (for example, 5 seconds) has elapsed since returning. Before that, the vehicle starts to move to the right side of the lane corresponding to the inside of the curve.

  As a result, in the straight section St, the movement to return from the right side of the lane to the center of the lane and the movement to move from the center of the lane to the right side of the lane are performed in a relatively short time, and the occupant feels a lateral G. There is a risk of letting it go. Further, such a track is not efficient from the viewpoint of fuel consumption.

  Therefore, when the second curve exists within a predetermined distance from the first curve, the travel trajectory planning unit 14 of the third modification plans a series of travel trajectories up to the second curve as well as the first curve. To do.

  Note that when the first curve and the second curve are separated from each other by a predetermined distance or more, the above-described problem hardly occurs. Further, when the traveling time in the straight section St is relatively long, it is better to return to the center of the lane than to continue traveling while staying on the right side of the lane. Therefore, here, as a condition for planning a series of traveling tracks up to the second curve, it is adopted that the first curve and the second curve are within a predetermined distance. The predetermined distance may be appropriately designed. Of course, as another aspect, a series of traveling tracks up to the second curve may be planned regardless of the distance between the first curve and the second curve.

  The travel control ECU 1 in the third modification may be operated according to the procedure shown in FIG. 11, for example. As a preparation process for the following process, the travel path planning unit 14 includes the first curve information indicating the road structure of the first curve and the second curve information indicating the road structure of the second curve. When the front road information including is acquired, it is determined whether or not the first curve and the second curve are within a predetermined distance. The following process is a process when it is determined that the distance from the first curve to the second curve is within a predetermined distance based on the road information ahead.

  First, in step S100, the first curve trajectory that is the travel trajectory on the first curve is determined by the same procedure as in the above-described embodiment, and the travel position at the first curve exit point is determined. Thereby, it is determined whether the traveling position at the time of exiting the first curve (in other words, the time of entering the straight section) is on the right side or the left side of the lane center. For convenience, the side to which the travel position at the time of exiting the first curve with respect to the center of the lane belongs is referred to as the first curve exit side. The travel position at the time of exiting the first curve corresponds to the first curve exit position described in the claims.

  Next, in step S200, the second curve track, which is the travel track on the second curve, is determined by the same procedure as in the above-described embodiment, and the travel position at the second curve entry point is determined. Thereby, it is determined whether the traveling position at the time of entering the second curve (in other words, at the time of exiting the straight section) is on the right side or the left side of the lane center. For convenience, the direction to which the traveling position at the time when the vehicle enters the second curve with respect to the center of the lane is referred to as the second curve entry side. The travel position at the time of entering the second curve corresponds to the second curve entry position described in the claims.

  In step S300, it is determined whether or not the first curve exit side and the second curve exit side match, and if they match, the process proceeds to step S400. If they do not match, the process proceeds to step S500.

  In step S400, the traveling track of the straight section connecting the first curve and the second curve does not return to the center of the lane, but travels from the traveling position at the time of exiting the first curve to the time of entering the second curve. Plan a trajectory that goes directly to the location. In step S500, as in the case where the second curve does not exist within a predetermined distance from the first curve, a track that smoothly connects with the traveling track on the second curve is planned after returning to the center of the lane.

  According to the above configuration, even if the road structure is as shown in FIG. 10, for example, as shown in FIG. 12, after exiting the first curve, the vehicle enters the second curve. It is possible to plan an efficient trajectory that does not carry out unnecessary lateral movement in the meantime. As a result, it is possible to reduce the risk of causing the occupant to feel the lateral G during traveling in the straight section.

[Modification 4]
When the reception status of the GNSS receiver 3 is poor, the positioning accuracy may be deteriorated, and a detailed vehicle position in the lane may be unknown. When the reliability of the current position is thus lowered and the inner maintenance track is set as the traveling curve of the forward curve, the vehicle control unit 15 starts from the center of the lane at any timing. It becomes difficult to determine whether or not the running position should be started toward the lane marking inside the curve. This is because the exact remaining distance to the curve is unknown.

  The travel control ECU 1 disclosed in the fourth modification corresponds to such a situation, and may be specifically realized as follows.

  First, the current position specifying unit 12 sequentially acquires information serving as an index for evaluating the reliability of the positioning result of the GNSS receiver 3 from the GNSS receiver 3, and determines the reliability of the positioning result of the GNSS receiver 3. evaluate. Information serving as an index for evaluating the reliability of the positioning result of the GNSS receiver 3 is, for example, the number of navigation satellites captured by the GNSS receiver 3, the received signal strength of the navigation signal, the SN ratio, and the like. .

  Then, the current position specifying unit 12 sequentially determines whether or not the reliability of the positioning result is low based on the above-described index, and provides the determination result to the vehicle control unit 15. Note that the current position specifying unit 12 may use, for example, the variation in the vehicle width direction of the positioning result per certain time (for example, several seconds) by the GNSS receiver 3 as an index for evaluating the reliability.

  Also, the lane marking recognition unit 112 sequentially calculates an actual imaging amount that indicates the amount of the inner lane marking that can be recognized in the current captured image, and provides the actual imaging amount to the traveling track planning unit 14 and the vehicle control unit 15.

  The vehicle control unit 15 indicates that the reliability of the positioning result of the GNSS receiver 3 from the current position specifying unit 12 is at a low level in a state where the inner maintenance track is planned by the traveling track planning unit 14. Is provided, the actual imaging amount of the inner lane marking provided from the lane marking recognition unit 112 starts to be monitored.

  Then, when the actual image pickup amount of the inner lane marking starts to decrease or becomes equal to or less than a predetermined threshold, the running position starts to move toward the inside of the curve. The fact that the actual image pickup amount of the inner lane marking has started to decrease suggests that the vehicle has entered the curve.

  It should be noted that even in a situation where the amount of imaging of the inner division line tends to be insufficient, it can be expected that the position of the outline is sufficiently imaged to be recognized. Therefore, the vehicle control unit 15 estimates the position of the inner lane line based on the detected position of the contour line, and sets the travel path based on the recognized position of the contour line and the estimated position of the contour line. What is necessary is just to control a vehicle so that it may become a running position along.

  According to such an aspect, even when the reliability of the current position is at a low level, the travel position can be brought to the inside of the curve at an appropriate timing, and the lane marking recognition state is maintained even during the curve travel. The possibility of being able to be increased can be increased.

[Modification 5]
Whether the imaging amount of the inner lane marking on the curve satisfies the recognition requirement, various parameters such as the curvature radius R, lane width W, and lane marking realization mode are appropriately set for each parameter. It may be determined based on whether or not a predetermined condition (hereinafter referred to as element condition) is satisfied.

  For example, if the radius of curvature R is less than a predetermined threshold Rth and the realization mode of the inner lane marking is other than a solid line pattern, the recognition requirement determination unit 143 has to satisfy the recognition requirement during curve traveling. judge. Moreover, even if the implementation | achievement aspect of an inner side division line is a broken line pattern, when clearance L1 is below a predetermined threshold value, you may determine with recognition requirements being satisfied.

  Various threshold values may be appropriately designed. The recognition element condition set for parameters other than the curvature radius R may be a condition corresponding to the curvature radius R. Information related to the recognition requirement is acquired by the road information acquisition unit 13.

  According to such an aspect, since it is not necessary to calculate a specific numerical value indicating the imaging amount, it is possible to determine whether or not the recognition requirement is satisfied by a simpler process.

[Modification 6]
In the above, the basic trajectory planning unit 141 exemplifies a mode of planning an out-in-out type trajectory as a traveling trajectory (hereinafter referred to as a basic trajectory) based on a preset basic trajectory determination method, but is not limited thereto. For example, the basic trajectory planning unit 141 may be configured to plan a trajectory having a lane center portion as a travel position as a basic trajectory in a curve. In addition, the basic trajectory in the curve may be an in-in-out type or out-in-in type orbit. In other words, the basic trajectory determination method may be any trajectory plan and may be defined in advance.

  The above-mentioned in / out type track is a track in which the travel position is closer to the inside of the lane than the center of the lane from the start point of the curve to the middle point, and the travel position is the center of the lane at the exit point. The trajectory is closer to the lane marking outside the curve. In addition, the out-in-in type track means that the running position is closer to the outside of the curve than the center of the lane at the starting point of the curve, and the driving position is from the center of the lane at the middle and exit points of the curve. Is the trajectory near the lane marking inside the curve.

  Further, even when the basic track is the out-in-out method, the method for determining the actual traveling track is not limited to the method described above. For example, when the traveling trajectory planning unit 14 once plans an out-in-out traveling trajectory in which the curvature radius of the traveling trajectory of the curve is maximized and determines that the recognition state at the time of curve traveling cannot be maintained on the traveling trajectory, Re-plan an out-in-out traveling track with a radius of curvature smaller than the maximum value by a predetermined amount. And it is good also as an aspect which makes the driving | running track in a curve approach the inner side maintenance track | truck gradually by repeating the re-planning of the driving | running track | truck of the out-in-out system which made the curvature radius small predetermined amount. In the process, when a travel track that can maintain the recognition state is obtained, the track may be adopted as an actual travel track.

[Modification 7]
When the periphery of the vehicle is relatively dark, such as when driving at night, in order for the image processing unit 11 to recognize the lane marking from the captured image of the in-vehicle camera 2, the road surface on which the lane marking is arranged is a headlight. Need to be illuminated by light from a light source such as This is because, when the periphery is dark, it is difficult to detect the lane marking that should have been included in the captured image due to insufficient luminance.

  Therefore, when it can be determined that the periphery of the vehicle is dark, it is preferable to determine whether or not the recognition requirement on the curve is satisfied in view of the positional relationship between the irradiation range of the headlight and the lane marking. Whether or not the vehicle periphery is dark may be determined based on the output of a well-known illuminance sensor that detects the brightness and whether or not the headlight is on.

  For example, the traveling control ECU 1 determines that the periphery of the vehicle is dark when the headlight is lit, and determines whether the recognition requirement is satisfied in view of the positional relationship between the irradiation range of the headlight and the lane marking. To do. Specifically, the imaging amount prediction unit 142 predicts the imaging amount of the inner curve line of the curve using a road surface area where the irradiation range of the headlight and the effective imaging range of the in-vehicle camera 2 overlap as a true effective imaging range. Then, the recognition requirement determination unit 143 determines whether the recognition requirement is satisfied based on the imaging amount.

  The irradiation range of the headlight with respect to the vehicle may be specified based on a parameter indicating the irradiation angle range of the headlight. Whether or not the headlight is lit may be determined based on the connection state of a switch that switches the lighting state of the headlight. Note that the irradiation range of the headlight is preferably specified by distinguishing between a high beam and a low beam, which can be provided as a lighting state of the headlight.

[Modification 8]
In relation to the modified example 7, when the irradiation range (hereinafter referred to as the irradiation mode) of the headlight on the road surface is configured to be adjustable in the host vehicle, the traveling control ECU 1 shown in the above-described embodiment and various modified examples You may control the irradiation direction of a headlight so that light can irradiate more inner division lines at the time of driving | running | working. Such an aspect is referred to as a modified example 8.

  This modification 8 may be realized by the system configuration shown in FIG. 13, for example. That is, the travel control ECU 1 is connected to the light control ECU 8 through a communication network (that is, a LAN: Local Area Network) built in the vehicle so that the light control ECU 8 can communicate with the headlight unit 9. They are connected so that they can communicate with each other.

  The headlight unit 9 includes a headlight 91 as a light source and a motor 92 for changing the irradiation direction of the headlight 91 to the vehicle width direction. The motor 92 is driven based on an instruction from the light control ECU 8, and changes the irradiation direction of the headlight 91 in the vehicle width direction (in other words, the horizontal direction).

  As a conventional technique for dynamically controlling the irradiation direction of the headlight, for example, an AFS (Adaptive Front-lighting System) that controls the irradiation direction of the low beam in the vehicle width direction according to the steering angle and the vehicle speed, etc. There is. A specific configuration for changing the irradiation direction of the headlight can also be realized with the aid of a known configuration used in an AFS system or the like.

  The light control ECU 8 is an ECU that controls the operation of the headlight unit 9, and switches on / off the headlight 91 or changes the irradiation direction of the headlight 91 in cooperation with the motor 92.

  The travel control ECU 1 having such a configuration may be operated as follows, for example. In other words, the travel control ECU 1 first, in step S6, based on the forward road information acquired by the road information acquisition unit 13, the travel position in the lane defined as the basic track, and the current irradiation range of the headlight 91. Thus, the length of the lane marking existing area included in the irradiation range of the headlight 91 (hereinafter referred to as irradiation division dose) is calculated.

  When the irradiation section dose is insufficient with respect to the imaging amount necessary to satisfy the recognition requirement, the irradiation direction of the headlight 91 in the direction in which the irradiation section dose increases in cooperation with the light control ECU 8. To change. For example, as shown in FIG. 14, when the forward curve is a right curve, the irradiation direction is set to the right side of the front direction of the vehicle.

  And if the irradiation direction dose alone cannot secure a sufficient irradiation section dose to satisfy the recognition requirements, or the irradiation section dose is sufficient, the imaging amount itself determined from the effective imaging range of the in-vehicle camera 2 is not sufficient. If not, a travel path that satisfies the recognition requirements is planned by performing steps S8 to S15.

  In FIG. 14, an area indicated by a symbol Cmr represents an effective imaging range of the in-vehicle camera 2. Further, the area indicated by the symbol Hdft represents the irradiation range when the front direction of the vehicle is the irradiation direction (in other words, the default irradiation range), and the region indicated by the symbol Hchg represents the irradiation range after the irradiation direction change. Yes. An alternate long and short dash line represents a lane marking area, and a solid line portion on the alternate long and short dash line represents an irradiation division dose obtained by changing the irradiation direction of the headlight 91.

  The angle (hereinafter referred to as the displacement angle) θ that changes the irradiation direction from the front direction of the vehicle is an amount that the predicted irradiation section dose is insufficient with respect to the imaging amount necessary for satisfying the recognition requirement (hereinafter, the insufficient amount). It is preferable to set the angle in accordance with Further, the displacement angle θ may be set in advance according to the curvature of the forward curve and the steering angle.

  According to the above configuration, when the traveling control ECU 1 determines that the overlap between the irradiation range of the headlight 91 and the lane marking area is insufficient, the traveling control ECU 1 adjusts the irradiation direction and tries to increase the irradiation division dose. . If the recognition requirement is not satisfied even if the attempt is made, the traveling track satisfying the recognition requirement is re-planned.

  Therefore, according to the above-described configuration, in the above-described modification example 7, the risk of planning a travel trajectory where the travel position is brought closer to the inside of the curve due to the lack of the irradiation section dose is reduced. Can do.

  In addition, although the aspect which tried to increase an irradiation division dose by adjusting the irradiation direction of the headlight 91 was illustrated above, it is not restricted to this. For example, the headlight unit 9 may include an irradiation angle mechanism that adjusts a range (in other words, an irradiation angle) in which the irradiation light spreads with respect to the optical axis direction of the headlight 91. In such a case, the traveling control ECU 1 may attempt to increase the irradiation section dose by increasing the irradiation angle of the headlight 91. Of course, it is good also as an aspect which tries the increase in irradiation division dose combining the adjustment of an irradiation angle, and the adjustment of an irradiation direction.

[Modification 9]
When the vehicle-mounted camera 2 is configured to be able to adjust the imaging direction (that is, the yaw angle) in the horizontal direction, the travel control ECU 1 performs the above-described various recognition state maintenance policies and the adjustment of the yaw angle of the vehicle-mounted camera 2. A combination may be tried to increase the imaging amount.

  For example, when the forward curve is a right curve, the yaw angle of the in-vehicle camera 2 is directed to the vehicle right side by a predetermined angle. The angle for changing the yaw angle may be a value corresponding to the curvature of the forward curve, the steering angle, or the like. By directing the imaging direction of the in-vehicle camera 2 toward the inside of the curve, an increase in the length (that is, the imaging amount) of the lane marking existing area included in the effective imaging range can be expected.

  Therefore, according to the configuration of the modification 9, by adjusting the yaw angle of the in-vehicle camera 2, the amount of moving the travel position from the travel trajectory planned by the basic trajectory plan unit 141 toward the inner lane line side can be suppressed, It is possible to suppress the frequency of changing the lane to satisfy the recognition requirement.

[Modification 10]
Although the aspect which employs the in-vehicle camera 2 as an apparatus for providing information for recognizing the position of the lane marking to the travel control ECU 1 (imaging apparatus described in claims) is described above, the present invention is not limited thereto. The imaging device may be a laser radar. This is because the received light intensity, detection distance, and the like of the reflected light acquired by the laser radar function as information representing the image of the object existing in the detection range. Data indicating the detection result of the laser radar is also included in the concept of the captured image described in the claims.

  When a laser radar is employed as the imaging device, the image processing unit 11 may analyze the distance to the target detected by the laser radar, the received light intensity of the reflected light, and the like to recognize the position of the lane marking. A known algorithm may be used as an algorithm for recognizing the marking line from the distance to the target detected by the laser radar, the received light intensity of the reflected light, and the like.

[Other variations]
In the above, the aspect in which the radius of curvature R is adopted as an index representing the shape of the road has been exemplified, but naturally, instead of the radius of curvature R, the curvature (= 1 / R) may be adopted as an index representing the shape of the road. Good.

  Moreover, although the aspect which installs the vehicle-mounted camera 2 so that the predetermined range ahead of a vehicle may be imaged above was illustrated, it does not restrict to this. You may install so that the desired range of a vehicle back and a side may be image | photographed. The same applies when a laser radar is employed as the imaging device. What is necessary is just to design the imaging range of the imaging device with respect to a vehicle suitably. However, the imaging device needs to be set so that a lane marking indicating the boundary of the lane in which the host vehicle is traveling can be captured. Specifically, it is preferable that the imaging range includes a range that is within a predetermined distance from the front wheel or the rear wheel.

100 travel control system, 1 travel control ECU, 2 vehicle-mounted camera, 3 GNSS receiver, 4 map data storage unit, 5 steering ECU, 6 power control ECU, 7 brake ECU, 11 image processing unit, 12 current position specifying unit, 13 Road information acquisition unit, 14 traveling track planning unit, 15 vehicle control unit, 111 image acquisition unit, 112 lane marking recognition unit, 141 basic track planning unit, 142 imaging amount prediction unit, 143 recognition requirement determination unit, 144 track correction unit

Claims (9)

Used in vehicles,
A road information acquisition unit (13) for acquiring front road information which is information indicating a structure of a road existing in front of the vehicle;
An image acquisition unit (111) for acquiring a captured image of an imaging device that captures a predetermined range around the vehicle;
Whether the current position of the vehicle is specified based on a navigation signal transmitted by a navigation satellite included in the satellite navigation system, and whether or not the reliability of position information indicating the current position is low based on the reception status of the navigation signal A current position specifying unit (12) for determining whether or not;
A lane marking recognition unit (112) for recognizing the position of the lane marking in the captured image;
Based on a predetermined basic trajectory determination method, a travel trajectory plan that plans a travel trajectory of the vehicle as a basic trajectory with respect to a travel lane marking that is a lane marking indicating a boundary of a lane in which the vehicle is traveling on a straight road and a curve. Part (14);
A vehicle control unit (15) for performing control for the vehicle to travel along the traveling track planned by the traveling track planning unit;
When the vehicle travels on a curve existing ahead of the vehicle along the travel trajectory planned by the travel trajectory planning unit, the imaging device can capture an inner lane marking that is the travel lane marking inside the curve. The imaging amount indicates whether or not the lane marking recognition unit satisfies the recognition requirement for recognizing the position of the inner lane marking from the captured image, indicating the mounting position of the imaging device and the imageable range in the vehicle. A recognition requirement determination unit (143) for determining based on imaging parameters and the road information ahead,
The recognition requirement determination unit determines whether the imaging amount in the curve satisfies the recognition requirement when the curve travels along the basic trajectory,
The traveling trajectory planning unit replans an inner maintenance trajectory that is a trajectory traveling inside the curve from the basic trajectory when the recognition requirement determining unit determines that the imaging amount in the curve does not satisfy the recognition requirement. And
The lane marking recognition unit is configured to identify an actual imaging amount that is an amount that can be imaged currently of the traveling lane line that is the inner lane marking in the curve during traveling in a straight section,
In the situation where the vehicle control unit is determined to be in a state where the reliability is low by the current position specifying unit, and the inner maintenance track is adopted as the traveling track in the curve, the section A travel control device configured to start moving the travel position to the inside of the curve when it is detected that the actual imaging amount specified by the line recognition unit starts to decrease or when the actual image capture amount is equal to or less than a predetermined threshold. Used in vehicles,
A road information acquisition unit (13) for acquiring front road information which is information indicating a structure of a road existing in front of the vehicle;
An image acquisition unit (111) for acquiring a captured image of an imaging device that captures a predetermined range around the vehicle;
A current position specifying unit (12) for specifying the current position of the vehicle;
A lane marking recognition unit (112) for recognizing the position of the lane marking in the captured image;
A travel trajectory planning unit (14) for planning a travel trajectory of the vehicle with respect to a travel lane marking that is the lane marking indicating the boundary of the lane in which the vehicle is traveling;
A vehicle control unit (15) for performing control for the vehicle to travel along the traveling track planned by the traveling track planning unit;
When the vehicle travels on a curve existing ahead of the vehicle along the travel trajectory planned by the travel trajectory planning unit, the imaging device can capture an inner lane marking that is the travel lane marking inside the curve. The imaging amount indicates whether or not the lane marking recognition unit satisfies the recognition requirement for recognizing the position of the inner lane marking from the captured image, indicating the mounting position of the imaging device and the imageable range in the vehicle. A recognition requirement determination unit (143) for determining based on imaging parameters and the road information ahead,
The recognition requirement determination unit is configured to determine that the recognition requirement is not satisfied when the curvature radius of the curve is less than a predetermined threshold and the inner division line in the curve is not a solid line pattern. And
When the recognition requirement determination unit determines that the imaging amount in the curve does not satisfy the recognition requirement, the traveling trajectory planning unit changes the traveling position with respect to the traveling lane line so that the imaging amount increases. A travel control device characterized by replanning a travel track. Used in vehicles,
A road information acquisition unit (13) for acquiring front road information which is information indicating a structure of a road existing in front of the vehicle;
An image acquisition unit (111) for acquiring a captured image of an imaging device that captures a predetermined range around the vehicle;
A current position specifying unit (12) for specifying the current position of the vehicle;
A lane marking recognition unit (112) for recognizing the position of the lane marking in the captured image;
A travel trajectory planning unit (14) for planning a travel trajectory of the vehicle with respect to a travel lane marking that is the lane marking indicating the boundary of the lane in which the vehicle is traveling;
A vehicle control unit (15) for performing control for the vehicle to travel along the traveling track planned by the traveling track planning unit;
When the vehicle travels on a curve existing ahead of the vehicle along the travel trajectory planned by the travel trajectory planning unit, the imaging device can capture an inner lane marking that is the travel lane marking inside the curve. The imaging amount indicates whether or not the lane marking recognition unit satisfies the recognition requirement for recognizing the position of the inner lane marking from the captured image, indicating the mounting position of the imaging device and the imageable range in the vehicle. A recognition requirement determination unit (143) for determining based on imaging parameters and the road information ahead,
The forward road information includes information on whether or not there is an adjacent lane that has the same direction as the traveling lane that is the lane in which the vehicle is currently traveling,
The traveling track planning unit
Based on a predetermined basic trajectory determination method, the traveling trajectory on a straight road and a curve is planned as a basic trajectory,
When the recognition requirement determination unit determines that the imaging amount in the curve does not satisfy the recognition requirement in the basic track, the internal maintenance track that is a track traveling inside the curve from the basic track is re-planned. Is configured to
Further, the travel trajectory planning unit is determined not to satisfy the recognition requirement even if the inner maintenance track is adopted by the recognition requirement determination unit, and the adjacent in the direction of the curve outside the curve. A travel control device configured to plan the travel track to change lanes before entering the curve to the adjacent lane when a lane exists. In claim 3 ,
The traveling track planning unit
Determining again whether or not the imaging amount on the traveling track obtained by re-planning the traveling position in the traveling lane so that the imaging amount becomes large satisfies the recognition requirement;
If it is determined that the imaging amount on the re-planned traveling track does not satisfy the recognition requirement, the adjacent lane exists in both the direction of the curve outside and the direction of the curve inside the curve. Whether or not
When the adjacent lane exists in both the direction outside the curve and the direction inside the curve in the curve, the imaging amount of the inner division line is larger when the lane is changed to the adjacent lane in which direction. Determine whether
A travel control device that plans the travel track to change lanes before entering the curve to the adjacent lane where the imaging amount of the inner lane line increases. In claim 3 or 4 ,
The road information ahead is
Information on whether there is an adjacent lane that has the same direction as the travel lane that is the lane in which the vehicle is currently traveling, and
Lane marking information indicating whether or not the lane marking provided in the travel lane and the adjacent lane is provided by a solid line pattern,
The traveling track planning unit includes the adjacent lane in a direction inside the curve in the curve, the inner division line of the traveling lane in the curve is not a solid line pattern, and an inner side of the adjacent lane. When the lane marking has a solid line pattern, the travel control device plans the travel track to change lanes to the adjacent lane before entering the curve. In any one of Claim 2 to 5 ,
The traveling track planning unit
Planning the traveling trajectory on a straight road and a curve based on a predetermined basic trajectory determination method,
The recognition requirement determination unit, when the curve travels along the basic trajectory that is the travel trajectory planned based on the basic trajectory determination method, the imaging amount in the curve satisfies the recognition requirement Determine whether or not to
The travel trajectory planning unit re-plans a trajectory that travels inside the curve from the basic trajectory when the recognition requirement determination unit determines that the imaging amount in the curve does not satisfy the recognition requirement. A traveling control device. In claim 6 ,
The road information acquisition unit includes, as the front road information, first curve information about a first curve that is a first curve that the vehicle will travel from and second information about a second curve that is a curve that travels next. Curve information and
The traveling track planning unit
By planning a first curve track that is the travel track of the first curve, a first curve exit position that is a travel position at the time of exiting the first curve is determined,
By planning a second curve trajectory that is the travel trajectory of the second curve, a second curve entry position that is a travel position at the time of entering the second curve is determined,
When the first curve exit position and the second curve entry position are on the same side with respect to the lane center, the straight section existing between the first curve and the second curve A travel control apparatus that plans a trajectory that travels straight from the first curve exit position to the second curve entry position as a travel trajectory. In claim 6 or 7 ,
The current position specifying unit is
Identifying the current position of the vehicle based on a navigation signal transmitted by a navigation satellite provided in the satellite navigation system,
Based on the reception status of the navigation signal, determine whether or not the reliability of the position information indicating the current position is low,
The lane marking recognition unit identifies an actual imaging amount that is an amount that is currently captured of the traveling lane marking that is the inner lane marking in the curve during traveling in a straight section,
The vehicle control unit is determined to be in a state where the reliability is low by the current position specifying unit, and a track closer to the inside of the curve than the basic track is adopted as the traveling track in the curve. In this situation, when it is detected that the actual imaging amount specified by the lane marking recognition unit has started to decrease, or when the detected amount becomes equal to or less than a predetermined threshold, the running position starts to move toward the inside of the curve. A travel control device. In any one of Claim 1 to 8 ,
An imaging amount prediction unit (142) that predicts the imaging amount of the inner lane marking on the curve based on an imaging parameter indicating the mounting position of the imaging device in the vehicle, the front road information, and the traveling track. A travel control device comprising:

Images