JP2012233713A - Road shape estimation device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a road shape estimation device that estimates a shape of a road on which a vehicle travels, with higher accuracy.SOLUTION: The road shape estimation device mounted on a vehicle to estimate the shape of a road on which the vehicle travels includes: an object detecting part that detects locations of stationary objects around the vehicle as a plurality of detection points; a connection line forming part that sequentially connects the detection points with line segments using a first connection method to form a connection line indicating the shape of the road; a duplex section recognizing part that recognizes a part or all of the sections of the connection line whose shape satisfies a predetermined condition, as a duplex road-side object arrangement section where road-side stationary objects are arranged in a duplex manner along the road; a connection line correcting part that connects the detection points included in the duplex road-side object arrangement section again using a second connection method when the duplex road-side object arrangement section is detected, to correct the connection line; and a road shape estimation part that estimates the shape of the road on the basis of the connection line.

Description

  The present invention relates to a road shape estimation apparatus, and more particularly to a road shape estimation apparatus that is mounted on a vehicle and estimates the shape of a road on which the vehicle is traveling.

  2. Description of the Related Art Conventionally, an in-vehicle system has been developed that estimates the shape of a road on which a vehicle travels, controls the steering of the vehicle according to the road shape, and notifies the danger of a vehicle collision. In the in-vehicle system as described above, it is necessary to accurately estimate the shape of the road in order to appropriately control the vehicle. An apparatus for estimating such a road shape is disclosed in, for example, Patent Document 1.

  The forward object detection device disclosed in Patent Literature 1 detects the position and shape of a roadside stationary object (road structure) such as a guardrail based on a plurality of detection points obtained from a radar device. Specifically, the front object detection device calculates a connection line formed by connecting adjacent detection points by a line among a plurality of detection points obtained by the radar device, and the connection line is stationary on a roadside such as a guardrail. Detect as an object. Generally, a roadside stationary object such as a guardrail is arranged along a road on which a vehicle travels, and has a shape similar to the road. Therefore, the forward object detection device can estimate and calculate the road shape based on the shape of the detection point group representing the roadside stationary object such as the guardrail detected as described above.

JP 2004-271513 A

  However, in the conventional device disclosed in Patent Document 1 and the like, there are cases where the shape of the roadside stationary object cannot be accurately detected. For example, as shown in FIG. 11, along the road on which the host vehicle 101 travels, the inner guard rail 53 and the outer guard rail 54 are arranged so as to overlap each other as a roadside stationary object when viewed from the host vehicle 101. Suppose. In addition, FIG. 11 is a figure which shows a mode that the shape of roadside stationary objects, such as a guardrail, is detected accidentally by the conventional apparatus.

  As shown in FIG. 11, when a plurality of guard rails are arranged so as to overlap, detection points indicating the positions of different guard rails may be erroneously connected. More specifically, a detection point Pa1 indicating the inner guard rail 53 and a detection point Pb1 indicating the outer guard rail 54 are connected, and a detection point Pb1 indicating the outer guard rail 54 and a detection point Pa2 indicating the inner guard rail 53 are connected. May end up. The connection line LD obtained by sequentially connecting the detection points in this way has, for example, a triangular wave shape (zigzag shape), which is a shape far from the actual guard rail shape. That is, in the conventional apparatus, when the guard rails are arranged in double along the road, the shape of the guard rail cannot be accurately detected, and the road shape may not be accurately estimated.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a road shape estimation device that can accurately estimate the shape of a road on which the host vehicle travels.

  In order to solve the above problems, the present application adopts the following configuration. That is, the first invention is a road shape estimation device that is mounted on a host vehicle and estimates the shape of the road on which the host vehicle travels, and detects the positions of stationary objects around the host vehicle as a plurality of detection points. A connecting line forming unit that forms a connecting line indicating the shape of the road by sequentially connecting a plurality of detection points with a line segment by the first connecting method, and a part or all of the connecting line A section that recognizes the section as a double roadside object arrangement section in which roadside stationary objects are arranged twice along the road, When a double roadside object arrangement section is detected, a connection line correction unit that corrects the connection line by reconnecting a plurality of detection points included in the double roadside object arrangement section by the second connection method, and a connection line A road shape estimation unit for estimating the shape of the road based on Comprising a road shape estimating device.

  In a second aspect based on the first aspect, the predetermined condition includes a first condition that an angle formed by a continuous line segment through each detection point is within a predetermined range. It is characterized by.

  In a third aspect based on the second aspect, the predetermined condition includes a second condition that the lengths of a plurality of line segments continuous through the respective detection points are within a predetermined range. The double section recognizing unit recognizes a part or all of the connection line as a double roadside object arrangement section on condition that at least either the first condition or the second condition is satisfied. It is characterized by that.

  According to a fourth aspect of the present invention, in any one of the first to third aspects of the present invention, when the part of or all of the connection lines have a triangular wave shape, the double section recognition unit It is recognized as a double roadside object arrangement section.

  In a fifth aspect based on the fourth aspect, at least one of the first condition and the second condition is determined in advance for the plurality of continuously connected line segments. In the case where it is continuously satisfied more than the number of times, a part or all of the connection line composed of the plurality of line segments is recognized as a double roadside object arrangement section.

  A sixth invention is the invention according to any one of the first to fifth inventions, wherein the connection line correction unit is configured to connect a plurality of detection points previously connected by the connection line forming unit in the double road side object arrangement section. A reconnection line forming unit that forms a plurality of reconnection lines by reconnecting every other connection based on the order in which they are connected, and a reconnection line that exists relatively inside the road among the plurality of reconnection lines. And a reconnection line selection unit that uses the connection line as a corrected connection line.

  According to a seventh aspect based on the sixth aspect, the reconnection line selection unit is configured to make relative movement along the road based on the position in the vehicle width direction of the own vehicle of the detection point that is the starting point of each of the plurality of reconnection lines. It is characterized in that a reconnection line existing inside is identified.

  According to an eighth aspect based on the sixth or seventh aspect, the reconnection line selection unit is arranged along the road based on the average value of the positions in the vehicle width direction of the own vehicle of the detection points constituting each reconnection line. It is characterized in that a reconnection line existing relatively inside is discriminated.

  According to a ninth invention, in any one of the first to eighth inventions, a reliability calculation unit that calculates a reliability indicating the possibility that the connecting line is a roadside stationary object arranged along a road, and an object An area that is a blind spot as viewed from the detection unit is detected, and a blind spot connection part that connects the detection points with line segments by the third connection method is further provided in the area, and the number of detection points that configure the connection line is The vehicle from the detection point that is the starting point of the connection line to the host vehicle is defined as Condition A that is less than or equal to a predetermined connection hierarchy threshold, and Condition B that the reliability is less than or equal to a predetermined reliability threshold. If the distance in the traveling direction is longer than a predetermined distance threshold, the ratio of the number of detection points connected by the third connection method out of the total number of detection points constituting the connection line is It must be greater than the specified ratio threshold If the D, conditions A, condition B, condition C, if any one of the conditions D is satisfied, characterized in that the dual segment recognition unit does not perform the detection of the double roadside object placement section.

  According to the first invention, the shape of the road on which the host vehicle travels can be estimated more accurately than in the past. Specifically, for example, a section (double roadside object placement section) in which roadside stationary objects such as guardrails are doubled and the connection line is not formed correctly is detected, and the connection of the section is detected. By correcting the line, it is possible to obtain an accurate connection line according to the roadside stationary object. By such processing, it is possible to accurately estimate the shape of the road on which the host vehicle travels based on an accurate connection line that matches the roadside stationary object.

  According to the second invention, the double roadside object arrangement section can be recognized more accurately. For example, if the length of the connecting line, that is, the length between detection points, is extremely long or extremely short compared to the interval between guard rails that are generally arranged in double, it is constituted by the line. There is a high possibility that the section is not a double roadside arrangement section. Therefore, the double roadside object arrangement section can be detected more accurately by not recognizing such a shape as the double roadside object arrangement section.

  According to the third invention, the double roadside object arrangement section can be recognized more accurately. Specifically, when the angle formed by the line segments constituting the connection line is relatively large, that is, when the connection line has a relatively linear shape, the shape is in line with the roadside stationary object and is double There is a high possibility that it is not a roadside arrangement section. Therefore, the double roadside object arrangement section can be detected more accurately by not recognizing such a shape as the double roadside object arrangement section.

  According to the fourth invention, it is possible to easily recognize a section in which roadside stationary objects such as guardrails are arranged in a double manner. When a connection line is formed on a road on which roadside stationary objects such as guardrails are doubled, detection points indicating different roadside stationary objects may be alternately connected to form a triangular wave shape. Therefore, by detecting such a triangular wave-shaped section, it is possible to easily detect a section in which roadside stationary objects are arranged twice.

  According to the fifth invention, when a plurality of conditions are continuously satisfied, the section can be recognized more accurately by recognizing the double roadside object arrangement section.

  According to the sixth invention, the connection line can be corrected to a shape along the roadside stationary object by a simple correction process.

  According to the seventh and eighth inventions, among the plurality of connection lines obtained when the connection lines are corrected, the connection lines existing inside can be identified by a simple process.

  According to the ninth aspect, the conditions A to D indicating that the connection line is unlikely to be formed based on the detection point indicating the roadside stationary object arranged along the road such as the guardrail. When it is satisfied, the process of recognizing the double roadside object arrangement section can be omitted. Therefore, the load on the processing apparatus can be reduced.

The block diagram which shows an example of a structure of the road shape estimation apparatus 1 which concerns on embodiment of this invention. The figure which shows an example of the detection point which the radar apparatus 11 which concerns on embodiment of this invention detected directly An example of the flowchart which shows the detail of the process which ECU12 which concerns on embodiment of this invention performs An example of the flowchart which shows the detail of the connection line formation process which ECU12 which concerns on embodiment of this invention performs The figure which shows a mode that the connection line was formed by the connection line formation process An example of the flowchart which shows the detail of the recognition target determination process which ECU12 which concerns on embodiment of this invention performs An example of the flowchart which shows the detail of the double guardrail recognition process which ECU12 which concerns on embodiment of this invention performs Partial enlarged view of the connecting line JT shown in FIG. The figure which shows a mode that the detection point in double guardrail area WA was reconnected by ECU12 which concerns on embodiment of this invention. The figure which shows the connecting wire corrected by ECU12 which concerns on embodiment of this invention The figure which shows a mode that the shape of roadside stationary objects, such as a guardrail, is detected accidentally by the conventional apparatus.

  Hereinafter, a road shape estimation apparatus 1 according to an embodiment of the present invention will be described. The road shape estimation device 1 according to the present invention is a device that is mounted on the host vehicle 100 and estimates the shape of the road on which the host vehicle 100 travels. Hereinafter, the road on which the host vehicle 100 travels is referred to as the host vehicle traveling road.

  First, the hardware configuration of the road shape estimation apparatus 1 will be described with reference to FIG. FIG. 1 is a block diagram showing an example of the configuration of the road shape estimation apparatus 1 according to the embodiment of the present invention. As shown in FIG. 1, the road shape estimation device 1 includes a radar device 11 and an ECU 12. The ECU 12 is electrically connected to a vehicle control device 50 mounted on the host vehicle 100.

  The radar device 11 is a device that detects the positions of stationary objects existing around the host vehicle 100 as a plurality of detection points, for example, as shown in FIG. FIG. 2 is a diagram illustrating an example of detection points directly detected by the radar apparatus 11 according to the embodiment of the present invention. In FIG. 2, detection points Pa1 to Pa4 (indicated by ● in FIG. 2) indicating the inner guard rail 51, detection points Pb1 to Pb6 (indicated by □ in FIG. 2) indicating the outer guard rail 52, and a detection point Pc1 indicating the preceding vehicle 200. An example is shown in which the radar device 11 detects (Δ mark in FIG. 2). The radar device 11 is mounted on the front end of the host vehicle 100 and detects an object existing in front of the host vehicle 100. The radar device 11 is typically an FM-CW radar device that transmits and receives electromagnetic waves in the millimeter wavelength band. For example, the radar device 11 irradiates a detection wave signal such as an electromagnetic wave in front of the host vehicle 100. Then, the position of the reflection point is detected as a detection point based on the reflected wave of the detection wave signal reflected by the object.

  As shown in FIG. 2, when the radar apparatus 11 has the front end of the host vehicle 100 as the origin and the host vehicle 100 is viewed in plan, the axis indicating the front-rear direction of the host vehicle 100 is the Y axis, and the Y axis and the horizontal plane The position information of the detection point is acquired in the XY coordinate system with the axis that intersects perpendicularly and indicates the vehicle width direction of the vehicle 100 as the X axis. Further, the radar device 11 determines whether each detection point indicates a stationary object or an object indicating another vehicle such as a preceding vehicle or an oncoming vehicle. The radar apparatus 11 may determine whether each detection point indicates a stationary object or another vehicle using a conventionally known method. Hereinafter, a detection point indicating a stationary object is referred to as a stationary object detection point, and a detection point indicating another vehicle is referred to as an other vehicle detection point. The radar device 11 transmits position information (XY coordinates) of each detection point detected in this way to the ECU 12. The radar device 11 may extrapolate the detection points using any conventionally known method. Extrapolation is the prediction of the position of the detection point at the current sampling from the position and relative speed of the detection point captured at the past sampling, and when the detection point is not captured near the predicted position. This is a technique that assumes that a detection point actually exists at the specified position. The radar apparatus 11 also transmits information regarding the detection points obtained by extrapolation in this way to the ECU 12 in the same manner as the detection points directly detected.

  The ECU 12 is typically an electronic control device that includes an information processing device such as a CPU (Central Processing Unit), a storage device such as a memory, an interface circuit, and the like. The ECU 12 is electrically connected to the vehicle control device 50.

  The vehicle control device 50 is a control device such as a brake control device, a steering control device, and an alarm device. The brake control device, the steering control device, and the alarm device each control the travel of the host vehicle 100 according to the shape of the host vehicle travel road acquired from the ECU 12. For example, the brake control device and the steering control device control the traveling direction and traveling speed of the host vehicle 100 so that the host vehicle 100 does not deviate from the host vehicle traveling road. Further, the alarm device predicts a collision between a roadside stationary object such as a guardrail that is expected to be present at the end of the traveling road of the host vehicle and the host vehicle 100 and notifies the driver of the host vehicle 100 of the danger of the collision by voice or the like. Raise an alarm. That is, when the road shape estimation device 1 correctly detects the shape of the vehicle traveling road, the vehicle control device 50 can execute appropriate vehicle control.

  Next, a process executed by the ECU 12 will be described with reference to FIG. FIG. 3 is an example of a flowchart showing details of processing executed by the ECU 12 according to the embodiment of the present invention. For example, when the IG power supply of the host vehicle 100 is set to the on state, the ECU 12 starts the process of the flowchart of FIG. When the process of the flowchart of FIG. 3 is started, the ECU 12 first executes the process of step S1. Note that the ECU 12 repeatedly executes these processes with the processes from step S1 to step S9 shown below as one cycle.

  In step S <b> 1, the ECU 12 acquires detection point information from the radar device 11. When the ECU 12 completes the process of step S1, the process proceeds to step S2.

  In step S2, the ECU 12 executes a connection line forming process. The connection line forming process is a process of forming a connection line by sequentially connecting a plurality of detection points acquired in step S1 with line segments. The connection line forming process is the same as the process proposed by the present applicant in Japanese Patent Application No. 2011-021965 (unpublished at the time of the present application). For details, refer to the gazette according to the application. The details of the connection line forming process will be described below with reference to FIG. FIG. 4 is an example of a flowchart showing details of the connection line forming process executed by the ECU 12 according to the embodiment of the present invention. When the ECU 12 starts the connecting line forming process shown in FIG. 4, the ECU 12 first executes a process of step S21.

  In step S21, the ECU 12 calculates a blind spot area DA. The blind spot area DA is an area that becomes a blind spot when viewed from the radar device 11. The ECU 12 may calculate the blind spot area DA using any conventionally known method. For example, the ECU 12 calculates the blind spot area DA based on the detection point indicating the position of the preceding vehicle 200 (see FIG. 2). More specifically, the ECU 12 considers that the preceding vehicle 200 exists in the rectangular area VA calculated based on a detection point (for example, the detection point Pc1 in FIG. 2) indicating the position of the preceding vehicle 200. Then, the ECU 12 calculates, as a blind spot area DA, an area beyond the rectangular area VA when viewed from the radar apparatus 11 among areas surrounded by a straight line passing from the radar apparatus 11 through the contour end point of the rectangular area VA. Note that the ECU 12 does not calculate the blind spot area when there is no detection point indicating the position of the preceding vehicle 200. When the ECU 12 completes the process of step S21, the process proceeds to step S22.

  In step S22, the ECU 12 executes a detection point connection process. The detection point connection process is a process of connecting detection points existing outside the blind spot area DA with line segments. ECU12 may connect detection points using the conventionally well-known arbitrary methods. For example, the ECU 12 sets a predetermined connection range on the basis of the detection point serving as the connection source, and uses the detection points existing within the connection range as the connection destination detection points, thereby detecting the connection source detection points and the connection destinations. Connect points with line segments. Then, the connection destination detection point is set as a new connection source detection point. The ECU 12 sequentially connects the connection points starting from a detection point (for example, the detection point Pa1 in FIG. 2) whose Y coordinate is closest to the host vehicle 100. In addition, ECU12 memorize | stores the connection order of each detection point which comprises a connection line in a memory | storage device. When the ECU 12 completes the process of step S22, the process proceeds to step S23.

  In step S23, the ECU 12 determines whether or not the blind spot area DA has been calculated by the above-described processing. If the ECU 12 has calculated the blind spot area DA, the process proceeds to step S24, and the detection points in the blind spot area DA are connected. On the other hand, when the blind spot area DA is not calculated, the ECU 12 advances the process to step S3 in FIG.

  In step S24, the ECU 12 executes blind spot detection point connection processing. The blind spot detection point connection process is a process of connecting the detection points existing in the blind spot area DA with line segments. Specifically, for the detection points existing in the blind spot area DA, the ECU 12 sets the connection range larger than the connection range used in the process of step S22 described above and connects the detection points. When the ECU 12 completes the process of step S24, the process proceeds to step S25.

  In step S25, the ECU 12 executes a reconnection process. Specifically, the ECU 12 connects the connection line outside the blind spot area DA formed in step S22 and the connection line inside the blind spot area DA formed in step S24. In addition, ECU12 memorize | stores the connection order of each detection point which comprises the connection line after a reconnection process in a memory | storage device. When the ECU 12 completes the process of step S25, the process proceeds to step S3 of FIG.

  An example of the connection line JT formed by the connection line formation process described above is shown in FIG. FIG. 5 is a diagram illustrating a state in which the connection line JT is formed by the connection line formation process. More specifically, FIG. 5 shows the connection line JT obtained when the connection line forming process is performed on the detection points shown in FIG. As shown in FIG. 5, detection points Pa1 to Pa4 indicating the inner guard rail 51 and detection points Pb1 to Pb4 indicating the outer guard rail 52 are alternately connected, and a part of the connection line JT forms a triangular wave shape. Yes. Note that the connection line JT is configured such that each detection point is connected in the order of Pa1, Pb1, Pa2, Pb2, Pa3, Pb3, Pa4, Pb4, Pb5, and Pb6, and the ECU 12 stores the connection order of these detection points. Hereinafter, detection points constituting the connection line JT are referred to as configuration detection points.

  In step S3, the ECU 12 executes a recognition target determination process. The recognition target determination process is a process for determining whether or not the connection line JT formed in step S2 is a target for performing the double guardrail recognition process in step S5 described later. The double guardrail recognition process is a process for determining whether or not a double guardrail section exists in the road section represented by the connection line JT. In addition, a double guardrail section refers to the section where the strip | belt-shaped roadside stationary objects, such as a guardrail, are arrange | positioned double along the road. Details of the recognition target determination process will be described below with reference to FIG. FIG. 6 is an example of a flowchart showing details of the recognition target determination process executed by the ECU 12 according to the embodiment of the present invention. When the recognition target determination process shown in FIG. 6 is started, the ECU 12 first executes the process of step S31.

  In step S31, the ECU 12 calculates the connection hierarchy number K. The connection hierarchy number K is a value indicating the number of detection points constituting the connection line. When the ECU 12 completes the process of step S31, the process proceeds to step S32.

  In step S32, the ECU 12 determines whether or not the connection layer number K is equal to or less than the connection layer threshold value Kth. The connection hierarchy threshold value Kth is a threshold value for determining whether or not the connection line is a target for performing the double guardrail recognition process based on the connection hierarchy number K. The connection hierarchy threshold value Kth is a constant stored in advance in the storage device of the ECU 12 and is, for example, 6. If the ECU 12 determines that the connection hierarchy number K is equal to or less than the connection hierarchy threshold Kth, the ECU 12 advances the process to step S40. On the other hand, if the ECU 12 determines that the number K of connection layers is greater than the connection layer threshold Kth, the process proceeds to step S33.

  In step S33, the ECU 12 calculates the reliability R. The reliability R is a numerical value indicating the high possibility that the connection line indicates a roadside stationary object such as a guardrail. The ECU 12, for example, according to whether or not the detection points constituting the connection line are extrapolation points and / or whether or not the detection points constituting the connection line have been detected in the previous processing cycle. Thus, the reliability R is calculated by changing the magnitude. The reliability R is the same as the total reliability ΣR proposed by the applicant in Japanese Patent Application No. 2011-021965 (unpublished at the time of this application). For details of the calculation method, refer to the gazette related to the application. I want to be. Note that the ECU 12 may calculate the reliability R using any conventionally known method. When the ECU 12 completes the process of step S33, the process proceeds to step S34.

  In step S34, the ECU 12 determines whether or not the reliability R is equal to or less than the reliability threshold Rth. The reliability threshold value Rth is a threshold value for determining whether or not the connection line is a target for performing the double guardrail recognition process based on the reliability R. The reliability threshold value Rth is a constant stored in the storage device of the ECU 12 in advance. If the ECU 12 determines that the reliability R is equal to or less than the reliability threshold value Rth, the ECU 12 proceeds with the process to step S40. On the other hand, when the ECU 12 determines that the reliability R is greater than the reliability threshold Rth, the ECU 12 proceeds with the process to step S35.

  In step S35, the ECU 12 acquires the starting point distance Py. The start point distance Py is a distance in the Y-axis direction (the front-rear direction of the host vehicle 100) from the detection point that is the start point of the connection line JT to the host vehicle 100. For example, in FIG. 5, the Y coordinate of the detection point Pa1 corresponds to the start point distance Py. When the ECU 12 completes the process of step S35, the process proceeds to step S36.

  In step S36, the ECU 12 determines whether or not the starting point distance Py is equal to or greater than the starting point distance threshold value Pyth. The starting point distance threshold value Pyth is a threshold value for determining whether or not the connection line is a target for performing the double guardrail recognition process based on the starting point distance Py. The starting point distance threshold value Pyth is a constant stored in advance in the storage device of the ECU 12, and is a value corresponding to 60 (m), for example. If the ECU 12 determines that the starting point distance Py is greater than or equal to the starting point distance threshold value Pyth, the ECU 12 advances the process to step S40. On the other hand, if the ECU 12 determines that the start point distance Py is not greater than or equal to the start point distance threshold value Pyth, the ECU 12 advances the process to step S37.

  In step S37, the ECU 12 calculates a blind spot detection point ratio D. The blind spot detection point ratio D is a ratio of the number of detection points included in the blind spot area DA to the total number of detection points constituting the connection line JT. The ECU 12 may calculate the blind spot detection point ratio D using any conventionally known method. When the ECU 12 completes the process of step S37, the process proceeds to step S38.

  In step S38, the ECU 12 determines whether the blind spot detection point ratio D is greater than or equal to the ratio threshold value Dth. If the ECU 12 determines that the blind spot detection point ratio D is equal to or greater than the ratio threshold value Dth, the ECU 12 advances the process to step S40. On the other hand, if the ECU 12 determines that the blind spot detection point ratio D is smaller than the ratio threshold Dth, the process proceeds to step S39.

  In step S40, the ECU 12 sets the double guardrail recognition target flag stored in the storage device of the ECU 12 to an off state. The double guardrail recognition target flag is flag data indicating whether or not the connection line JT is a target for performing the double guardrail recognition processing in step S5 described later. When the double guardrail recognition target flag is set to the on state, it indicates that the connection line JT is a target for performing the double guardrail recognition process. When the double guardrail recognition target flag is set to the off state, the connection line JT is Indicates that it is not subject to double guardrail recognition processing. When the ECU 12 completes the process of step S40, the process proceeds to step S4 of FIG.

  In step S39, the ECU 12 sets the double guardrail recognition target flag to the on state. When the ECU 12 completes the process of step S39, the process proceeds to step S4 of FIG.

  Returning to the description of FIG. 3, in step S <b> 4, the ECU 12 determines whether or not the connection line JT is a target to be subjected to double guardrail recognition processing. Specifically, the ECU 12 determines whether or not the double guardrail recognition target flag is on. If the double guardrail recognition target flag is on, the ECU 12 determines that the connection line JT is a double guardrail recognition target, and proceeds to step S5. On the other hand, when the ECU 12 determines that the double guardrail recognition target flag is in the OFF state and is not a double guardrail recognition target, the ECU 12 proceeds with the process to step S8.

  According to the processing of step S3 and step S4 described above, when it is unlikely that the connection line JT represents a roadside stationary object arranged along a road such as a guardrail, the connection line JT is subject to double guardrail recognition processing. Excluded from. Specifically, when the number K of connection layers is relatively small, the reliability R is relatively low, the start point distance Py is relatively long, or the blind spot detection point ratio D is relatively large, the connection line JT is excluded from the object of the double guardrail recognition process. According to such processing, unnecessary processing can be omitted and the load on the ECU 12 can be reduced.

  In step S5, the ECU 12 executes a double guardrail recognition process. As described above, the double guardrail recognition process is a process for determining whether or not there is a double guardrail section in which the guardrails are disposed twice in the road section represented by the connection line JT. The details of the double guardrail recognition process will be described below with reference to FIG. FIG. 7 is an example of a flowchart showing details of the double guardrail recognition process executed by the ECU 12 according to the embodiment of the present invention. When the ECU 12 starts the double guardrail recognition process shown in FIG. 7, it first executes the process of step S51.

  In step S51, the ECU 12 selects a detection point (detection point Pb1 in FIG. 5) connected to the start point of the connection line JT. Hereinafter, the detection point selected by the ECU 12 in the double guardrail recognition process is referred to as a selection detection point. When the ECU 12 completes the process of step S51, the process proceeds to step S52.

  In step S52, the ECU 12 calculates the connection angle θ. The connection angle θ is an angle formed by a continuous line segment through the selection detection point. FIG. 8 is a partially enlarged view of the connection line JT shown in FIG. For example, when the detection point Pb1 is a selection detection point, the ECU 12 forms a line segment T1 connecting the detection point Pb1 and the detection point Pa1, and a line segment T2 connecting the detection point Pb1 and the detection point Pa2. The angle θ1 is calculated as the connection angle θ. Note that any conventionally known method may be used as a method for the ECU 12 to calculate the connection angle θ. When the ECU 12 completes the process of step S52, the process proceeds to step S53.

  In step S53, the ECU 12 determines whether or not the connection angle θ is equal to or smaller than the angle threshold θth. The angle threshold value θth is a threshold value for determining whether or not a part of the connection line JT has a shape indicating a double guardrail section based on the connection angle θ. The angle threshold θth is an arbitrary constant stored in advance in the storage device of the ECU 12, and is 45 (°), for example. If the ECU 12 determines that the connection angle θ is equal to or smaller than the angle threshold θth, the ECU 12 advances the process to step S54. On the other hand, when the ECU 12 determines that the connection angle θ is larger than the angle threshold θth, the ECU 12 advances the process to step S62.

  In step S54, the ECU 12 calculates a line segment length Lα indicating the length of the line segment connected via the selection detection point. For example, when the detection point Pb1 is selected as the selection detection point in FIG. 8, the line segment length Lα1 of the line segment T1 and the line segment length Lα2 of the line segment T2 are calculated. The ECU 12 may calculate the line segment length Lα using any conventionally known method. When the ECU 12 completes the process of step S54, the process proceeds to step S55.

  In step S55, the ECU 12 determines whether or not the line segment length Lα is included in a predetermined range. Specifically, it is determined whether or not the line segment length Lα is larger than the lower limit line segment length Lαth1 and the line segment length Lα is smaller than the upper limit line segment length Lαth2 (Lαth1 ≦ Lα ≦ Lαth2). The lower limit line segment length Lαth1 and the upper limit line segment length Lαth2 are threshold values for determining whether or not a part of the connection line JT has a shape indicating a double guardrail section based on the line segment length Lα. . The lower limit line segment length Lαth1 and the upper limit line segment length Lαth2 are both constants stored in advance in the storage device of the ECU 12. For example, the lower limit line segment length Lαth1 is set to 1 (m), and the upper limit line segment length Lαth2 is 3 (m) is set. When the detection point Pb1 is selected as the selection detection point in FIG. 8, the ECU 12 includes both the line segment length Lα1 of the line segment T1 and the line segment length Lα2 of the line segment T2 within the above range. Determine whether or not. If the ECU 12 determines that Lαth1 ≦ Lα ≦ Lαth2, the process proceeds to step S56. On the other hand, if the ECU 12 determines that Lαth1 ≦ Lα ≦ Lαth2, the process proceeds to step S62.

  In step S56, the ECU 12 calculates a corrected line segment length Lβ. The corrected line segment length Lβ is a length indicating the distance between detection points connected when the connecting line JT is corrected. Specifically, the ECU 12 calculates a distance between two detection points connected to the selected detection point as a corrected line segment length Lβ. When the detection point Pb1 is selected as the selected detection point in FIG. 8, the ECU 12 calculates the distance Lβ1 from the detection point Pa1 to the detection point Pa2 as the corrected line segment length Lβ. When the ECU 12 completes the process of step S56, the process proceeds to step S57.

  In step S57, it is determined whether or not the corrected line segment length Lβ is included in a predetermined range. Specifically, it is determined whether or not the corrected line segment length Lβ is larger than the lower limit corrected line segment length Lβth1 and the corrected line segment length Lβ is smaller than the upper limit corrected line segment length Lβth2 (Lβth1 ≦ Lβ ≦ Lβth). . Each of the lower limit correction line segment length Lβth1 and the upper limit correction line segment length Lβth2 is for determining whether a part of the connecting line JT has a shape indicating a double guardrail section based on the correction line segment length Lβ. It is a threshold value. The lower limit correction line segment length Lβth1 and the upper limit correction line segment length Lβth2 are both constants stored in advance in the storage device of the ECU 12. For example, the lower limit correction line segment length Lβth1 is set to 0.5 (m), and the upper limit The corrected segment length Lβth2 is set to 2 (m). If the ECU 12 determines that Lβth1 ≦ Lβ ≦ Lβth2, the process proceeds to step S58. On the other hand, if the ECU 12 determines that Lβth1 ≦ Lβ ≦ Lβth2, the process proceeds to step S62.

  In step S58, the ECU 12 increments the establishment counter C. The establishment counter C is a count value indicating the number of times that the conditions shown in steps S53, S55, and S57 are satisfied. The initial value of the establishment counter C is, for example, zero. In step S58, the ECU 12 adds, for example, 1 to the establishment counter C as a predetermined constant value, and stores the value after the addition in the storage device. When the ECU 12 completes the process of step S58, the process proceeds to step S59.

  In step S59, the ECU 12 determines whether or not the value of the establishment counter C is 1. That is, it is determined whether or not the conditions shown in steps S53, S55, and S57 are satisfied for the first time. If the value of the establishment counter C is 1, the ECU 12 advances the process to step S60. On the other hand, when the value of the establishment counter C is not 1, the ECU 12 advances the process to step S61.

  In step S60, the ECU 12 sets the currently selected selection detection point as the start point of the double guardrail section. When the ECU 12 completes the process of step S60, the process proceeds to step S61.

  In step S61, the ECU 12 selects one of the configuration detection points in the currently connected order. Specifically, as shown in FIG. 8, when the detection points are connected in the order of Pa1, Pb1, Pa2, and Pb2, and the detection point Pb1 is selected as the selection detection point, the ECU 12 skips the detection point Pa2. Thus, the detection point Pb2 is selected as the next selected detection point. By repeating such processing, the ECU 12 sequentially selects the detection points Pb1, Pb2, and Pb3 as selection detection points in FIG. When the ECU 12 completes the process of step S61, the process returns to step S52.

  In step S62, the ECU 12 determines whether or not the establishment counter C is greater than or equal to the counter threshold value Cth. The counter threshold value Cth is a threshold value for determining the presence / absence of a double guardrail section based on the value of the establishment counter C. The counter threshold value Cth is a constant stored in advance in the storage device of the ECU 12, and is a value such as 6, for example. If the ECU 12 determines that the establishment counter C is equal to or greater than the counter threshold value Cth, the ECU 12 advances the process to step S63. On the other hand, if the ECU 12 determines that the establishment counter C is less than the counter threshold value Cth, the ECU 12 initializes information on the start point of the double guardrail section stored in the storage device, and advances the process to step S64.

  In step S63, the ECU 12 sets the currently selected selection detection point as the terminal point of the double guardrail section. When the ECU 12 completes the process of step S63, the process proceeds to step S64.

  In step S64, the ECU 12 resets the establishment counter C. Specifically, the ECU 12 returns the value of the establishment counter C to the initial value and stores it overwritten. When the ECU 12 completes the process of step S64, the process proceeds to step S65.

  In step S65, the ECU 12 determines whether or not the end of the connection line has been reached. Specifically, the ECU 12 determines whether there is a next selectable configuration detection point. If there is no selectable configuration detection point, the ECU 12 determines that the end of the connection line has been reached, and proceeds to step S6 in FIG. On the other hand, when there is a selectable configuration detection point, the ECU 12 determines that the end of the connection line has not been reached, and advances the process to step S61.

  According to the above double guardrail recognition processing, when a triangle shape whose line segment length Lα is within a predetermined range and the angle formed by the line segment is equal to or smaller than a predetermined value is continuously detected a predetermined number of times, the line segment L The section is recognized as a double guardrail section. In the section where the guardrails are doubly arranged, it is easy to obtain such a zigzag connecting line JT with a continuous triangular shape. By recognizing such a shape, the double guardrail section can be accurately recognized. can do.

  Returning to the description of FIG. 3, in step S <b> 6, the ECU 12 determines whether or not the double guardrail section is included in the connection line JT. Specifically, it is determined whether or not the start point and the end point of the double guardrail section are set in the double guardrail recognition process in step S5. When the start point and the end point of the double guardrail section are set, the ECU 12 determines that the double guardrail section is included in the connection line JT, and advances the process to step S7. On the other hand, when the start point and the end point of the double guardrail section are not set, the ECU 12 determines that the double guardrail section is not included in the connection line JT, and advances the process to step S8.

  In step S7, the ECU 12 corrects the connection of the detection points in the double guardrail section. Specifically, first, the ECU 12 once deletes a line segment connected to the detection points constituting the double guardrail section. Next, every other detection point in the double guardrail section is reconnected by a line segment in the order in which it was originally connected.

  For example, in FIG. 5, it is assumed that the detection point Pa1 is set as the start point of the double guardrail section WA and the detection point Pb4 is set as the end point of the double guardrail section WA. First, the ECU 12 once deletes the line segments connecting the detection points Pa1, Pb1, Pa2, Pb2, Pa3, Pb3, Pa4, and Pb4 in the double guardrail section WA. Next, the ECU 12 skips the detection point Pb1 and reconnects the detection point Pa1 and the detection point Pa2 with a new line segment. Similarly, the ECU 12 connects the detection point Pa2 and the detection point Pa3, and connects the detection point Pa3 and the detection point Pa4. By such processing, a connection line JA indicating the inner guard rail 51 is formed as shown in FIG. FIG. 9 is a diagram illustrating a state in which the detection points in the double guardrail section WA are reconnected by the ECU 12 according to the embodiment of the present invention. On the other hand, the ECU 12 skips the detection point Pa2 and reconnects the detection point Pb1 and the detection point Pb2 with a new line segment. Similarly, the ECU 12 connects the detection point Pb2 and the detection point Pb3, and connects the detection point Pb3 and the detection point Pb4. By such processing, a connection line JB indicating the outer guard rail 52 is formed as shown in FIG.

  Next, the ECU 12 determines which of the connection line JA and the connection line JB is located inside the road on which the host vehicle 100 travels. Specifically, the ECU 12 determines that, of the connection line JA and the connection line JB, the X coordinate of the detection point that is the start point is closer to the host vehicle on the road inner side. Note that this process is an example, and the ECU 12 determines that the average value of the X coordinates of the detection points constituting each of the connection line JA and the connection line JB is closer to the host vehicle 100 on the inside of the road. It doesn't matter.

  Next, the ECU 12 leaves the connection line JA existing inside the road as a connection line in the double guardrail section among the connection lines JA and JB, and deletes the connection line JB existing outside (see FIG. 10). . FIG. 10 is a diagram showing connection lines corrected by the ECU 12 according to the embodiment of the present invention. When the ECU 12 completes the process of step S7, the process proceeds to step S8.

  As shown in FIG. 10, according to the processing from step S <b> 5 to step S <b> 7 described above, by correcting the connection line in the section where the guardrails are doubly arranged, the road area where the host vehicle 100 can actually travel is changed. A suitable connection line can be formed.

  In step S8, the ECU 12 outputs the connection line JA finally left as shown in FIG. 10 as the shape of the road on which the host vehicle 100 travels. In addition, ECU12 outputs as the shape of the road where the own vehicle 100 drive | works similarly about connection line JB2 outside a double guardrail area. When the ECU 12 completes the process of step S8, the process proceeds to step S9.

  In step S9, the ECU 12 determines whether or not the IG power source is set to off. If the ECU 12 determines that the IG power source is set to OFF, the ECU 12 proceeds with the process to step SEND. On the other hand, if the ECU 12 determines that the IG power source is not set to OFF, the ECU 12 returns the process to step S1.

  As described above, according to the road shape estimation apparatus according to the embodiment of the present invention, when the host vehicle 100 is traveling on a road on which roadside stationary objects such as guardrails are doubled, the road Can be estimated more accurately than in the past.

  In the above embodiment, the example in which the detection point (the detection point Pb1 in FIG. 5) connected to the start point of the connection line JT is selected as the selection detection point in step S51 has been described. However, the start point of the connection line JT is described. The third detection point (detection point Pa2 in FIG. 5) connected from the third point may be selected as the selected detection point. When performing such processing, the ECU 12 can sequentially select the detection points Pa1, Pa2, and Pa3 shown in FIG. 5 as selection detection points and recognize the presence or absence of the double guardrail section.

  The road shape estimation apparatus according to the present invention is useful as a road shape estimation apparatus that can accurately estimate the shape of the road on which the host vehicle is traveling.

1 Road shape estimation device 11 Radar device 12 ECU
DESCRIPTION OF SYMBOLS 50 Vehicle control apparatus 51, 53 Inner guard rail 52, 54 Outer guard rail 100, 101 Own vehicle 200 Prior vehicle

Claims (9)

A road shape estimation device that is mounted on a host vehicle and estimates a shape of a road on which the host vehicle travels,
An object detection unit for detecting the position of a stationary object around the vehicle as a plurality of detection points;
A connection line forming unit that forms a connection line indicating the shape of the road by sequentially connecting a plurality of the detection points with line segments by the first connection method;
When a part or all of the connecting line has a shape that satisfies a predetermined condition, the section is defined as a double roadside object arrangement section in which roadside stationary objects are arranged twice along the road. A double section recognition unit for recognizing;
A connection line correction unit that corrects the connection line by reconnecting the plurality of detection points included in the double roadside object arrangement section by the second connection method when the double roadside object arrangement section is detected; ,
A road shape estimation device comprising: a road shape estimation unit that estimates the shape of the road based on the connection line.   The first condition according to claim 1, wherein the predetermined condition includes a first condition that an angle formed by the continuous line segment through each of the detection points is within a predetermined range. The road shape estimation apparatus described. The predetermined condition includes a second condition that the lengths of the plurality of line segments continuous through the detection points are each within a predetermined range,
The double section recognition unit recognizes a part or all of the connection line as a double roadside object arrangement section on condition that at least one of the first condition and the second condition is satisfied. The road shape estimation apparatus according to claim 2, wherein:   The double section recognizing unit recognizes the section as the double roadside object arrangement section when a part or all of the connection line has a triangular wave shape. The road shape estimation apparatus according to any one of 1 to 3.   The double section recognizing unit is configured such that at least one of the first condition and the second condition is continuously satisfied for a predetermined number of times with respect to the plurality of continuously connected line segments. 5. The road shape estimation apparatus according to claim 4, wherein a part or all of the connection line composed of the plurality of line segments is recognized as a double roadside object arrangement section. The connection line correction unit is
In the double roadside object arrangement section, a plurality of reconnection lines are reconnected by reconnecting the plurality of detection points previously connected by the connection line forming unit based on the current connection order. A reconnection line forming part to be formed;
The reconnection line selection part which makes the said reconnection line which exists relatively inside along the said road among several said reconnection lines the said connection line after correction | amendment is characterized by the above-mentioned. The road shape estimation apparatus according to any one of 1 to 5.   The reconnection line selection unit is configured to detect the reconnection line that is located relatively inward along the road based on a position of the detection point, which is a starting point of each of the plurality of reconnection lines, in the vehicle width direction of the host vehicle. The road shape estimation apparatus according to claim 6, wherein a connection line is discriminated.   The reconnection line selection unit is configured so that the reconnection line is located on the inner side along the road based on an average value of positions of the detection points constituting the reconnection lines in the vehicle width direction of the host vehicle. The road shape estimation device according to any one of claims 6 to 7, wherein a connection line is discriminated. A reliability calculation unit for calculating a reliability indicating the possibility that the connection line is a roadside stationary object arranged along the road;
An area that becomes a blind spot as seen from the object detection unit is further provided, and a blind spot connection unit that connects the detection points with a line segment by a third connection method in the area is further provided,
The condition A is that the number of the detection points constituting the connection line is equal to or less than a predetermined connection layer threshold value, and the condition B is that the reliability is equal to or less than a predetermined reliability threshold value. Condition C is that the distance in the traveling direction of the host vehicle from the detection point that is the starting point of the line to the host vehicle is longer than a predetermined distance threshold, and the total number of the detection points constituting the connection line When the condition D is that the ratio of the number of detection points connected by the third connection method is greater than a predetermined ratio threshold, the condition A, the condition B, the condition C, the condition The road according to any one of claims 1 to 8, wherein when any one of D is satisfied, the double section recognition unit does not detect a double roadside object arrangement section. Shape estimation device.

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