JP2012103970A - Road shape estimating device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a road shape estimating device capable of estimating a road shape accurately.SOLUTION: A road shape estimating device, which is mounted on a vehicle and estimates a shape of the road on which the vehicle traveling, comprises: an object detection part for detecting positions of motionless objects around the vehicle as multiple detecting points; a connection path line forming part for forming multiple connection path lines by connecting the detecting points sequentially; a driving course candidate selection part for selecting the connection path lines that meet the prescribed conditions as the driving course candidates from the multiple connection path lines formed by the connection path line forming part; and a road shape estimating part for estimating the shape of the road based on the lines of the driving course candidates.

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 vehicle road shape recognition device disclosed in Patent Document 1 detects the position and shape of a roadside stationary object such as a guardrail based on a plurality of detection points obtained from a radio wave radar. Specifically, the vehicle road shape recognition device extracts a detection point group composed of adjacent detection points among a plurality of detection points obtained by a radio wave radar, and the detection point group is used as a roadside stationary object such as a guardrail. Detect as. 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 vehicle road shape recognition 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 2007-161162 A

  In the vehicular road shape recognition device as in Patent Document 1, detection points existing within a predetermined distance range within a fixed direction are simply connected and grouped. In such a simple process, when there are a plurality of detection points within the predetermined distance range, the shape of the group of connected detection points may be circular. In other words, the shape indicated by the group of detection points may be different from the shape of the roadside stationary object. In other words, the conventional technology may not be able to accurately detect the shape of the roadside stationary object. In such a case, it is difficult to accurately estimate the shape of the road.

  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 capable of accurately estimating a road shape.

  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 vehicle and estimates a shape of a road on which the vehicle travels, and detects an object position around a vehicle as a plurality of detection points. A connection route line forming unit that forms a plurality of connection route lines by sequentially connecting the detection point and the detection point, and a connection that satisfies a predetermined condition among the plurality of connection route lines formed by the connection route line formation unit A road shape estimation device comprising: a road candidate selection unit that selects a route line as a road candidate line; and a road shape estimation unit that estimates a road shape based on the road candidate line.

In a second aspect based on the first aspect, the connection route line forming unit forms a connection route line group including a plurality of connection route lines by sequentially connecting the detection points, and the runway candidate selection unit is connected Of the connection route lines included in the route line group, a connection route line that satisfies a predetermined condition is selected as a runway candidate line.

  According to a third aspect, in the second aspect, the connection route line forming unit includes a connection range setting unit that sets a connection range with reference to a detection point that is a connection source, and a plurality of detection points in the connection range. A route ship group forming a connection route line group by connecting each of a plurality of detection points existing in the connection range as a connection destination to a detection point as a connection source and a detection point as a connection destination. Part.

  According to a fourth aspect of the present invention, in any one of the first to third aspects, the runway candidate selection unit calculates the number of connections of the detection points constituting the connection route line for each connection route line, and the number of connections is the largest. Many connection route lines are selected as runway candidate lines.

  According to a fifth invention, in any one of the first to fourth inventions, the runway candidate selection unit determines a runway candidate line based on a position in the left-right direction viewed from the vehicle of the vehicle from a detection point constituting the connection route line. It is characterized by selecting.

  A sixth invention is characterized in that, in the fifth invention, the runway candidate selection unit selects, as the runway candidate line, the connection route line including the detection point whose left-right position as viewed from the vehicle is closest to the vehicle. To do.

  According to a seventh invention, in any one of the second to sixth inventions, the invention further includes a start point selection unit that selects a plurality of start points from a plurality of detection points, and the connection route line formation unit is configured to start from the start point. By connecting the detection points sequentially, a plurality of connection route line groups are formed for each start point, the runway candidate selection unit selects a plurality of runway candidate lines for each of the plurality of connection route line groups, and the road shape estimation device The road shape estimation unit further includes a road line selection unit that selects a road candidate line satisfying a predetermined condition as a road line, and the road shape estimation unit estimates the shape of the road based on the road line To do.

  The eighth invention is characterized in that, in the seventh invention, the runway line selection unit selects a runway candidate line including a start point whose position in the front-rear direction viewed from the vehicle is closest to the vehicle as the runway line.

  According to a ninth invention, in any one of the seventh and eighth inventions, based on the information on the past detection points stored in the storage unit, the present position of the past detection points is extrapolated as a detection point. An extrapolation processing unit, and the runway line selection unit detects a reliability that indicates a high possibility that the runway candidate line is a roadside stationary object arranged along the road. According to whether or not the point is an extrapolation point, calculation is made for each runway candidate line, and any of the runway candidate lines is selected as a runway line based on the magnitude of the reliability.

  According to the first invention, the road shape can be accurately estimated as compared with the conventional one. Specifically, a plurality of connection route lines are formed by connecting the detection points, and a shape along the roadside stationary object is selected by uniquely selecting a runway candidate line from these connection route lines based on a predetermined condition. A group of linear detection points that will form can be formed and selected. Then, the shape of the roadside stationary object can be accurately detected based on such a group of detection points, and the shape of the road on which the host vehicle travels can be accurately estimated based on the shape of the roadside stationary object.

According to the second invention, when connecting the detection points, a plurality of connection route lines that are likely to represent the shape of the roadside stationary object can be formed in order to form a connection route line group branched into a plurality of routes. it can. That is, a correct runway candidate line can be calculated. In addition, since it is possible to suppress the formation of connection route lines that are unlikely to represent the shape of a roadside stationary object, it is possible to reduce the amount of calculation processing and the storage area required for formation of connection route lines and selection of runway candidate lines. it can.

  According to the third aspect, the effect of the second aspect can be obtained with a simple process.

  According to the fourth aspect of the present invention, a connection route line that is considered to have a shape that matches the shape of the roadside stationary object can be selected as a running route candidate line. Specifically, when the connection route lines with a relatively small number of connected detection points are compared by trial and error of the inventors, the higher the number of connection of the detection points constituting the connection route line, the more the roadside stationary object. It was discovered that there is a high probability that the shape conforms to the shape. Therefore, it is possible to select a connection route line that is considered to form a shape in accordance with the shape of the roadside stationary object by selecting a route candidate line based on the number of connections of the detection points constituting the connection route line. it can.

  According to the fifth aspect, it is possible to estimate a road shape capable of appropriate vehicle control. Specifically, the road shape calculated by the road shape estimation apparatus according to the present invention may be finally used for prediction of deviation from the lane of the host vehicle, prediction of collision with a roadside stationary object, and the like. In this case, a connection route line including a detection point existing at a position close to the left and right direction from the vehicle (inside the road) and a connection route line including a detection point existing at a position far from the vehicle in the left and right direction (outside the road). Assume that it exists. Here, although the connection route line inside the road actually indicates the presence of a roadside stationary object such as a guardrail, the end of the road on which the vehicle travels is identified based on the connection route line outside the road In such a case, a collision between the guardrail and the host vehicle may not be predicted. In that respect, according to the fifth invention, it is assumed that a roadside stationary object exists relatively on the inner side of the road, for example, by using a connection route line including a detection point existing near the vehicle as a runway candidate line. Can do. Therefore, the road shape suitable for safe vehicle control can be estimated.

  According to the sixth aspect, it is possible to estimate a road shape suitable for safest vehicle control.

  According to the seventh aspect, the road shape can be estimated more accurately. Specifically, when a plurality of runway candidate lines are obtained, it is possible to select a group of detection points that form a shape along the roadside stationary object by uniquely selecting an appropriate runway line from among them. it can. Therefore, it is possible to detect a running route that accurately represents the shape of the roadside stationary object and accurately estimate the shape of the road on which the host vehicle travels based on the shape of the roadside stationary object.

  According to the eighth aspect, the effects of the seventh aspect can be obtained with a simple process.

The block diagram which shows an example of a structure of the road shape estimation apparatus 1 The figure which shows an example of the detection point which the radar apparatus 11 detected directly An example of a flowchart showing details of processing executed by the ECU 12 The figure which shows a mode that the extrapolation point was extrapolated in addition to the detection point detected in FIG. An example of a flowchart showing details of detection point connection processing executed by the ECU 12 An example of a flowchart showing details of a connection range setting process executed by the ECU 12 Diagram showing how the connection range is set The figure which shows the connection route line group formed by the detection point connection process based on the detection point shown in FIG. An example of a flowchart showing the details of the runway candidate line selection process executed by the ECU 12 The figure which shows a mode that a part of connection route line shown in FIG. 8 is excluded from the selection object of a runway candidate line by the process of step S61 and step S62. The figure which shows a mode that a runway candidate line is selected by the process of step S63 to step S69 from the connection route line shown in FIG. An example of a flowchart showing details of a route selection process executed by the ECU 12 An example of a flowchart showing details of a total reliability calculation process executed by the ECU 12 The figure which shows a mode that a track line is selected by the track line selection process from the track candidate line shown in FIG.

  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. 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, the radar apparatus 11 uses the front end O of the host vehicle 100 as the origin, the axis indicating the traveling direction of the host vehicle 100 as the Y axis, and the axis that intersects the Y axis perpendicularly on the horizontal plane as the X axis. The position information of the detection point is acquired in the XY coordinate system. Further, the radar apparatus 11 determines whether or not each detection point indicates a stationary object. The radar apparatus 11 may determine whether or not the detection point indicates a stationary object using a conventionally known method. For example, first, the radar apparatus 11 detects the relative speed of each detection point with respect to the host vehicle 100. And the radar apparatus 11 determines with the said detection point showing a stationary object, when a relative speed and the running speed of the own vehicle 100 are substantially the same value. The radar device 11 transmits the position information (XY coordinates) of the detection point determined to indicate a stationary object in this way to the ECU 12. Note that the radar device 11 may supplement the detection point at a position where no stationary object exists due to the influence of noise or the like.

  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. 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.

  In step S <b> 1, the ECU 12 acquires stationary object detection point information from the radar device 11. The ECU 12 stores the acquired position information of the detection points in the storage device in association with the acquired (sampled) time T (n). Note that the time T (n) indicates the latest time as the subscript n in parentheses () is larger. When the ECU 12 completes the process of step S1, the process proceeds to step S2.

  In step S <b> 2, the ECU 12 extrapolates the current position of the detection point based on the history information of the detection points detected in the past stored in the storage device of the ECU 12. 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 ECU 12 may extrapolate the position of the detection point using any known technique. Hereinafter, the detection points extrapolated by the process of step S2 are referred to as extrapolation points. On the other hand, a detection point directly detected by the radar device 11 is referred to as a direct detection point. The position information of the detection points extrapolated by the process of step S2 is stored in the storage device of the ECU 12 together with extrapolation flag data indicating that the detection points are extrapolation points. The extrapolation point is also stored in association with the sampled time T (n) in the same manner as the detection point. When the ECU 12 completes the process of step S2, the process proceeds to step S3.

  FIG. 4 illustrates how extrapolation points are extrapolated by the process of step S2. FIG. 4 is a diagram illustrating a state in which extrapolation points are extrapolated in addition to the direct detection points detected in FIG. 2. In FIG. 4, P8, P21, and P23 are extrapolated as extrapolation points. According to the process of step S2, even if the detection point of the stationary object that has been continuously detected is not temporarily detected due to the influence of noise or the like, the position of the detection point at the present time is estimated, It can be handled as being detected. Therefore, the shape of the roadside stationary object can be detected more accurately.

  In step S3, the ECU 12 sets a starting point. The start point determination process is a process for determining a start point from a plurality of detection points. The start point is a point that becomes a start point of a connection line formed by continuously connecting detection points. Based on the positional relationship between each of the plurality of detection points detected by the radar device 11 and the host vehicle 100, the ECU 12 determines a start point from among the plurality of detection points (for example, P1 to P7 in FIG. 2). The ECU 12 may determine the starting point using any method. For example, the ECU 12 preferably determines the starting point as described in International Application No. PCT / JP2010 / 006489. When the ECU 12 completes the process of step S3, the process proceeds to step S4.

  In step S4, the ECU 12 sets the starting point as the connection source. When the process of ECU 12 step S4 is completed, the process proceeds to step S5.

In step S5, the ECU 12 executes a detection point connection process. The detection point connection process is a process of connecting the detection points to form a connection route line group including a plurality of connection route lines. Hereinafter, the detection point connection process executed by the ECU 12 will be described with reference to FIG. FIG.
It is an example of the flowchart which shows the detail of the detection point connection process which CU12 performs. When the process of the flowchart of FIG. 5 is started, the ECU 12 first executes the process of step S51.

  In step S51, the ECU 12 executes a connection range setting process. The connection range setting process is a process of setting a range (hereinafter referred to as a connection range) for searching for a connection destination detection point from a connection source detection point when the detection points are sequentially connected. Hereinafter, a connection range setting process executed by the ECU 12 will be described with reference to FIG. FIG. 6 is an example of a flowchart showing details of the connection range setting process executed by the ECU 12. When the ECU 12 starts the process of the flowchart of FIG. 6, first, the ECU 12 executes a process of step S511.

  A state in which the connection range is set by the ECU 12 is shown in FIG. FIG. 7 is a diagram illustrating how the connection range is set. As shown in FIG. 7, the connection range is a rectangular area set with the connection source as a reference.

  In step S511, the ECU 12 calculates the vertical dimension Ly (see FIG. 7) of the connection range. Specifically, the ECU 12 calculates the vertical dimension Ly such that the vertical dimension Ly increases as the distance from the host vehicle 100 to the detection point that is the connection source increases. When the ECU 12 completes the process of step S511, the ECU 12 advances the process to step S512.

  In step S512, the ECU 12 calculates a lateral dimension Lx (see FIG. 7) of the connection range. Specifically, the ECU 12 calculates the lateral dimension Lx such that the lateral dimension Lx increases as the distance from the host vehicle 100 to the detection point that is the connection source increases. When the ECU 12 completes the process of step S512, the process proceeds to step S513.

  According to the processing in steps S511 and S512, the connection range is set to a wider range as the distance from the connection source detection point serving as a reference for setting the connection range to the host vehicle 100 is longer. Here, it is considered that a general radar device such as the radar device 11 tends to have a lower angular resolution as an object located farther away. That is, it is considered that the distance between the detection points becomes wider at a relatively long distance. Therefore, when connecting detection points that are relatively far away, it is preferable to search for detection points that are connection destinations in a wider range than when detecting detection points that are relatively close to each other. Therefore, if the size of the search range is changed according to the distance from the connection source to the vehicle as in steps S511 and S512, the detection points can be suitably connected.

In step S513, the ECU 12 calculates the connection range rotation angle θ. The connection range rotation angle θ is a rotation amount used when rotating the connection range. The ECU 12 calculates the connection range rotation angle θ according to the direction indicated by the line segment connected to the connection source. For example, as shown in FIG. 6, it is assumed that the ECU 12 calculates θc as the connection range rotation angle θ when an arbitrary detection point Pc is set as the connection source and the connection range Tc is set as the connection range. The detection point Pc is connected in advance to the detection point Pb via the line segment Qb based on the processing in step S8 described later. First, the ECU 12 calculates an angle ωbc formed by the line segment Qb and the Y axis based on the coordinates (cx, cy) of the detection point Pc, the coordinates (bx, by) of the detection point Pb, and the equation (1). .
ωbc = arctan {(cx−bx) / (cy−by)} (1)
Next, assuming that the connection range rotation angle θ calculated when the connection range Tb was previously set with the detection point Pb as a reference is θb, the ECU 12 calculates θc based on ωbc, θb, and Equation (2). .
θc = ωbc × α + (1−α) × θb (2)
Note that the coefficient α in Equation (2) is an arbitrary constant between 0 and 1. The ECU 12 calculates the value of the coefficient α as a smaller value as the number of detection points connected up to the connection source increases. When the ECU 12 completes the process of step S513, the process proceeds to step S514.

  It is considered that a detection point existing in the vicinity of an extension line of a connection line formed by sequentially connecting detection point groups is likely to be a part of the same stationary object as the detection point group. Therefore, by setting the connection range according to the direction indicated by the previously connected line segment as in step S513, it becomes easier to connect detection points that are highly likely to be the same stationary object, and the shape of the roadside stationary object is changed. It can be detected accurately.

  In step S514, the ECU 12 sets a connection range. Specifically, as shown in FIG. 6, the ECU 12 first sets a side in the lateral direction having a length of the lateral dimension Lx on the left and right with the detection point at the connection source as the center. Next, the ECU 12 sets a side in the longitudinal direction having a length of the vertical dimension Ly in the Y-axis direction from the connection source detection point. The ECU 12 sets the connection range by rotating the rectangular region surrounded by the four sides in the longitudinal direction and the lateral direction set in this way by the connection range rotation angle θ around the detection point of the connection source. To do. When the ECU 12 completes the process of step S514, the process proceeds to step S52 of FIG.

  Even if the stationary roadside object such as a guardrail is curved along the curve of the own vehicle traveling road by setting the connection range by appropriately rotating as shown in the connection range setting process, the detection point Can be connected well. In the above-described embodiment, an example in which the connection range is set as a rectangular area has been described. However, the present invention is not limited to the rectangular area and may have an arbitrary shape.

  Returning to the description of FIG. 4, in step S <b> 52, the ECU 12 determines whether or not a detection point exists within the connection range. If the ECU 12 determines that a detection point exists within the connection range, the ECU 12 proceeds with the process to step S53. On the other hand, if the ECU 12 determines that the detection point does not exist within the connection range, the ECU 12 completes the detection point connection process and advances the process to step S6 in FIG.

  In step S53, the ECU 12 selects a detection point having the shortest distance to the connection source among the detection points existing within the connection range as the connection destination. When the ECU 12 completes the process of step S53, the process proceeds to step S54.

  In step S54, the ECU 12 connects the connection source and the connection destination with a line segment. The ECU 12 may connect the connection source and the connection destination with a curve. When the ECU 12 completes the process of step S54, the process proceeds to step S55.

  In step S55, the ECU 12 sets the connection destination connected in step S8 as a new connection source. When the ECU 12 completes the process of step S55, the process returns to step S51.

According to the detection point connection process described above, a plurality of connection route lines are formed. Some of the plurality of connection route lines are branched from a common starting point. That is, according to the detection point connection process, a route line including a plurality of connection route lines is formed for each start point (hereinafter referred to as a connection route line group). FIG. 8 is a diagram showing a connection route line group formed by the detection point connection process based on the detection points shown in FIG. In FIG. 8, the connection point line group A including a connection route line starting from the detection point P1 and having the detection points P6, P10, and P11 as end points, and the detection point P6, P10, and P11 starting from the detection point P7. A connection path line group B including a connection path line group including a connection path line having a detection point P13 as a starting point and a connection path line group C including a connection path line having a detection point P13 as a termination point. A connection route line group D including connection route lines starting from the detection point P20 and starting from the detection points P19, P21, and P22 is formed. Thus, according to the detection point connection process described above, the connection route line group is formed in a tree shape as shown in FIG. 8, for example. The ECU 12 selects one runway candidate line from each of the connection route line groups in the following process. Further, the ECU 12 estimates the shape of the own vehicle traveling road by selecting the total route indicating the shape of the own vehicle traveling road from the selection of candidate traveling routes.

  In addition, according to the above-described detection point connection processing, it is possible to suppress the formation of a connection route line in which the detection point is not considered to represent the shape of a roadside stationary object such as an annular shape. That is, a correct runway candidate line can be calculated. Further, it is possible to reduce the calculation processing amount and storage area of the ECU 12 required for forming the connection route line and selecting the running route candidate line.

  Returning to the description of FIG. 3, in step S <b> 6, the ECU 12 executes a runway candidate line selection process. The runway candidate line selection process is a process of selecting a runway candidate line from a plurality of connection route lines included in the connection route line group. The ECU 12 selects a runway candidate line for each connection route line group. Hereinafter, with reference to FIG. 9, the candidate road line selection process executed by the ECU 12 will be described. FIG. 9 is an example of a flowchart showing details of the runway candidate line selection process executed by the ECU 12. When the ECU 12 starts the process of the flowchart of FIG. 9, first, the ECU 12 executes a process of step S61.

  In step S61, the ECU 12 determines whether or not there is a connection route line with the connection number J equal to or greater than the connection threshold value Jth. The connection number J is the number of detection points constituting the connection route line. The connection threshold value Jth is a threshold value for determining whether or not a connection route line is a target for selecting a runway candidate line according to the value of the number of connections J. The connection threshold Jth is an arbitrary constant stored in advance in the storage device of the ECU 12, for example, 6. If the ECU 12 determines that there is a connection route line with the connection number J equal to or greater than the connection threshold value Jth, the ECU 12 proceeds to step S62. On the other hand, if the ECU 12 determines that there is no connection route line having the connection number J equal to or greater than the threshold, the process proceeds to step S68.

  In step S62, the ECU 12 excludes the connection route line having the connection number J less than the connection threshold value Jt from the selection targets of the runway candidate lines. When the ECU 12 completes the process of step S62, the process proceeds to step S63.

  FIG. 10 is a diagram illustrating a state in which a part of the connection route lines illustrated in FIG. 8 is excluded from the selection targets of the runway candidate lines by the processing of Step S61 and Step S62. The value of the connection number J of the connection route lines starting from the detection point P1 or P7 shown in FIG. 8 and having the detection point P10 as the end point is 5, which is less than the connection threshold value Jt. Similarly, the value of the connection number J of connection path lines starting from the detection point P13 or P20 and ending at the detection point P21 is 5, which is less than the connection threshold value Jt. Therefore, these connection route lines are excluded from the selection targets of the runway candidate lines as shown in FIG. 10 by the processing of step S61 and step S62.

  Returning to the description of FIG. 9, in step S <b> 63, the ECU 12 selects a connection route line group that has not yet selected a runway candidate line. Hereinafter, the connection route line group selected in step S63 is referred to as a selected route line group. When the ECU 12 completes the process of step S63, the process proceeds to step S64.

In step S64, the ECU 12 determines whether or not the starting point of the selected route line group exists in the right road area AR. The right road side area AR is an area predetermined on the right front side of the host vehicle 100. For example, the right road area AR is a rectangular area where X = 1.4 to X = 15 and Y = 0 to Y = 60 (see FIG. 11). Note that the unit of the XY coordinate system when representing the area is meters (m). If the ECU 12 determines that the start point exists in the right road side area AR, the ECU 12 proceeds with the process to step S66. On the other hand, if the ECU 12 determines that the start point does not exist in the right road area AR, the ECU 12 advances the process to step S65.

  In step S65, the ECU 12 determines whether or not the starting point of the selected route line group exists in the left road area AL. The left road side area AL is a predetermined area on the left front side of the host vehicle 100. For example, the left road area AR is a rectangular area where X = −1.4 to X = −15 and Y = 0 to Y = 60 (see FIG. 11). If the ECU 12 determines that the start point exists in the left road area AL, the ECU 12 proceeds with the process to step S67. On the other hand, if the ECU 12 determines that the start point does not exist in the left road side area AL, the ECU 12 advances the process to step S68.

  In step S66, the ECU 12 selects a connection route line formed by sequentially connecting the leftmost detection points among the connection route lines included in the selected route line group as a running route candidate line. When the ECU 12 completes the process of step S66, the process proceeds to step S69.

  In step S67, the ECU 12 selects a connection route line formed by sequentially connecting the detection points located on the rightmost among the connection route lines included in the selected route line group as a running route candidate line. When the ECU 12 completes the process of step S67, the process proceeds to step S69.

  In step S68, the ECU 12 selects a connection route line having the maximum number of connections J among the connection route lines included in the selected route line group as a running route candidate line. When the ECU 12 completes the process of step S68, the process proceeds to step S69.

  In step S69, the ECU 12 determines whether or not all connection route line groups have been selected in step S63. If the ECU 12 determines that all the connection route line groups have not yet been selected, the ECU 12 returns the process to step S63. On the other hand, if the ECU 12 determines that all the connection route line groups have been selected, the process returns to step S7 in FIG.

  Here, with reference to FIG. 11, a description will be given of a situation in which the runway candidate line is selected by the processing from step S63 to step S69. Note that FIG. 11 is a diagram illustrating a state in which a runway candidate line is selected by the processing from step S63 to step S69 from the connection route line illustrated in FIG.

  The connection route line group A starting from the detection point P1 shown in FIG. 10 includes a connection route line having the detection point P6 as a termination point and a connection route line having the detection point P11 as a termination point. Yes. Here, the start point P1 exists in the left road area AL, and the detection point P6 exists on the right side of the detection point P11. Therefore, according to the processing from step S63 to step S69, as shown in FIG. 11, the connection route line having the detection point P1 as the start point and the detection point P6 as the end point is used as the runway candidate line of the connection route line group A. Selected. Similarly, in the connection route line group B starting from the detection point P7, a connection route line starting from the detection point P7 and ending at the detection point P6 is selected as a runway candidate line (see FIG. 11). ).

  On the other hand, the connection route line group C starting from the detection point P13 shown in FIG. 10 includes a connection route line having the detection point P19 as a termination point and a connection route line having the detection point P22 as a termination point. It is. Here, the start point P13 exists in the right road area AR, and the detection point P22 exists on the left side of the detection point P19. Therefore, by the processing from step S63 to step S69, as shown in FIG. 11, a connection route line having the detection point P13 as a start point and the detection point P22 as a termination point is selected as a runway candidate line of the connection route line group C. The Similarly, in the connection route line group D having the detection point P20 as the start point, a connection route line having the detection point P20 as the start point and the detection point P22 as the end point is selected as the runway candidate line (see FIG. 11). ).

  That is, according to the processing from step S63 to step S69, a route line that passes through the inside of the host vehicle travel road among the connection route lines included in the selected route line group is selected as a travel route candidate. Therefore, the road shape suitable for safe vehicle control can be estimated. Specifically, the road candidate line calculated by the ECU 12 may be used in the vehicle control device 50 for prediction of a collision between the host vehicle 100 and a roadside stationary object, or the like. At this time, the connection route line that passes relatively outside the host vehicle road is selected as the candidate route, and in fact, if there is a stationary roadside object such as a guardrail inside the connection route line, A collision with a stationary roadside object may not be predicted. In that regard, according to the processing from step S63 to step S69, a route line passing through the inside of the host vehicle traveling road is selected as a traveling route candidate. Therefore, in the processing of the vehicle control device 50, a roadside stationary object is located relatively inside the road. Can be considered to exist. Therefore, a road shape suitable for safe vehicle control can be estimated.

  Further, according to the runway candidate line selection process, for the connection lines having the connection number J less than the connection threshold Jth, the connection route line having the largest connection number J is selected as the runway candidate line. In this regard, according to the trial and error of the inventors, when connection route lines having a small number of connections J are compared, the more the number of connections J of the detection points constituting the connection, the more closely the shape of the roadside stationary object. It was discovered that there is a high probability that the shape is the same. Therefore, selecting a connection route line that is considered to form a shape that conforms to the shape of the roadside stationary object by selecting a road candidate line based on the number of connections J of the detection points constituting the connection route line. Can do.

  Returning to FIG. 3, in step S <b> 7, the ECU 12 executes a route selection process. The travel route selection process is a process of selecting a travel route that indicates the shape of the host vehicle travel road from a plurality of candidate travel lines. Hereinafter, the route line selection process executed by the ECU 12 will be described with reference to FIG. FIG. 12 is an example of a flowchart showing details of the route line selection process executed by the ECU 12. When the ECU 12 starts the process of the flowchart of FIG. 7, first, the ECU 12 executes a process of step S71.

  In step S71, the ECU 12 executes a total reliability calculation process. The total reliability calculation process is a process for calculating the total reliability ΣR of each track candidate line. The total reliability ΣR is a numerical value indicating a high possibility that the candidate road line indicates a roadside stationary object. ECU12 calculates total reliability (SIGMA) R based on the information regarding the detection point which comprises a lane candidate line. Hereinafter, the total reliability calculation process executed by the ECU 12 will be described with reference to FIG. FIG. 13 is an example of a flowchart showing details of the total reliability calculation process executed by the ECU 12. When the ECU 12 starts the process of the flowchart of FIG. 13, first, the ECU 12 executes a process of step S710.

  In step S710, the ECU 12 selects one track candidate line whose total reliability ΣR has not been calculated. In the following, the track candidate line selected in step S710 is referred to as a selected track candidate line. When the ECU 12 completes the process of step S711, the ECU 12 advances the process to step S711.

  In step S711, the ECU 12 selects one detection point that constitutes the selected runway candidate selection. Hereinafter, the detection point selected in step S711 is referred to as a selection detection point. The reliability R of the selected detection point is calculated by the processing from step S712 to step S724 described below. When the ECU 12 completes the process of step S711, the process proceeds to step S712.

In step S712, the ECU 12 determines whether there is a detection history of selected detection points. Specifically, it is determined whether there is an object that indicates the same object as the selected detection point from past detection point information stored in the storage device of the ECU 12. If the selected detection point is a stationary object, its position changes with time according to the traveling speed of the host vehicle 100. Therefore, for example, the ECU 12 estimates the position where the selection detection point would have existed at the time of the previous sampling based on the current position of the selection detection point and the traveling speed of the host vehicle 100. Then, when the history in which the detection points are supplemented in the vicinity of the estimated position at the time of the previous sampling is stored in the storage device of the ECU 12, the ECU 12 determines the history as the detection history of the selected detection points. Note that the ECU 12 is not limited to the above method, and may determine whether or not there is a detection history of the selected detection points using any conventionally known method. If it is determined that there is a detection history of the selected detection point, the ECU 12 advances the process to step S713. On the other hand, if the ECU 12 determines that there is no detection history of the selected detection point, the ECU 12 advances the process to step S720.

  In step S713, the ECU 12 determines whether or not the selection detection point at the current time T (n) is an extrapolation point. Specifically, determination is made based on whether extrapolation flag data is stored in the storage device of the ECU 12 for the selected detection point at the current time T (n). If the ECU 12 determines that the selected detection point at the current time T (n) is an extrapolation point, the ECU 12 advances the process to step S714. On the other hand, if the ECU 12 determines that the selected detection point is a direct detection point, the ECU 12 advances the process to step S717.

  In step S714, the ECU 12 determines whether or not the selection detection point is an extrapolation point in the past history. Specifically, the ECU 12 determines whether or not the selection detection point is an extrapolated point at the previous sampling time T (n−1). More specifically, the ECU 12 determines whether or not extrapolation flag data is stored for the selected detection point at the previous sampling T (n−1) with reference to the storage device of the ECU 12. When the ECU 12 determines that the selected detection point is an extrapolation point even at the previous sampling time T (n−1), that is, when it is determined that the selection detection point is a point extrapolated continuously in time, Advances to step S715. On the other hand, if the ECU 12 determines that the selected detection point is a direct detection point at the previous sampling time T (n−1), the ECU 12 advances the process to step S716.

  In step S715, the ECU 12 subtracts the constant α from the reliability R of the selected detection point. The constant α is an arbitrary positive constant determined in advance. The constant α is preset to 20, for example. The initial value of the reliability R may be an arbitrary numerical value such as 0, for example. When the ECU 12 completes the process of step S715, the process proceeds to step S721.

  In step S716, the ECU 12 subtracts the constant β from the reliability R. The constant β is an arbitrary positive constant smaller than α. The constant β is preset to 10, for example. When the ECU 12 completes the process of step S716, the process proceeds to step S721.

  In step S717, the ECU 12 determines whether or not the selected detection point is an extrapolation point at the previous sampling time T (n-1), as in step S714 described above. If the ECU 12 determines that the selected detection point is an extrapolated point at the previous sampling time T (n−1), the ECU 12 advances the process to step S718. On the other hand, if the ECU 12 determines that the selected detection point is a direct detection point even at the previous sampling time T (n−1), the ECU 12 advances the process to step S719.

  In step S718, the ECU 12 adds a constant β to the reliability R. When the ECU 12 completes the process of step S718, the process proceeds to step S721.

  In step S719, the ECU 12 adds a constant α to the reliability R. When the ECU 12 completes the process of step S719, the process proceeds to step S721.

In step S720, the ECU 12 adds a constant γ to the reliability R. The constant γ is
Any positive constant greater than α. The constant γ is preset to 30, for example. When the ECU 12 completes the process of step S720, the process proceeds to step S721.

  In step S721, the ECU 12 determines whether or not the value of the reliability R is equal to or greater than the reliability maximum value Rmax. The reliability maximum value Rmax is a maximum value that the reliability R can take. The reliability maximum value Rmax is a predetermined constant, and is set to 200, for example. If the ECU 12 determines that the value of the reliability R is equal to or greater than the reliability maximum value Rmax, the ECU 12 advances the process to step S722. On the other hand, if the ECU 12 determines that the value of reliability R is smaller than the reliability maximum value Rmax, the process proceeds to step S723.

  In step S722, the ECU 12 sets the value of the reliability R to the same value as the reliability maximum value Rmax. When the ECU 12 completes the process of step S722, the process proceeds to step S725.

  In step S723, it is determined whether or not the value of reliability R is equal to or less than reliability minimum value Rmin. The reliability minimum value Rmin is the minimum value that the reliability R can take. The reliability minimum value Rmin is a predetermined constant, and is set to 0, for example. If the ECU 12 determines that the value of the reliability R is equal to or less than the reliability minimum value Rmin, the ECU 12 advances the process to step S724. On the other hand, if the ECU 12 determines that the value of the reliability R is greater than the reliability minimum value Rmin, the process proceeds to step S725.

  In step S725, the ECU 12 sets the value of the reliability R to the same value as the reliability minimum value Rmin. When the ECU 12 completes the process of step S725, the process proceeds to step S726.

  According to the processing from step S711 to step S720, when the host vehicle 100 is stopped, the value of the reliability R may increase or decrease indefinitely. When the reliability R value increases or decreases infinitely in this way, the reliability R does not function as an index when selecting a track line in threshold determination using the reliability R in the processing described later. There is a fear. Therefore, the value of the reliability R is appropriately limited by clamping the reliability R so that the value of the reliability R is not less than the reliability minimum value Rmin and not more than the reliability maximum value Rmax by the processing from step S721 to step S724. The reliability R can be effectively functioned as an index when selecting a route.

  In step S725, the ECU 12 determines whether or not all detection points constituting the selected runway candidate line have been selected as selection detection points. If the ECU 12 determines that all the detection points constituting the selected runway candidate line have been selected as the selection detection points, the process proceeds to step S726. On the other hand, if the ECU 12 determines that all the detection points constituting the selected runway candidate line have not yet been selected, the process returns to step S711.

  In step S726, the ECU 12 adds the reliability R of each detection point to calculate the total reliability ΣR. When the ECU 12 completes the process of step S726, the process proceeds to step S727.

  According to the processing from step S711 to step S726, the ECU 12 sequentially switches the detection points that constitute the runway candidate line, and determines whether each of the detection points is an extrapolation point or a direct detection point. Increase or decrease the value of the total reliability ΣR. More specifically, when the selected detection point is an extrapolation point, the total reliability ΣR is calculated to be smaller than when the selected detection point is a direct detection point. In addition, when the selected detection points are extrapolated continuously in time, the value of the total reliability ΣR is further reduced.

  In step S727, the ECU 12 determines whether or not the calculation of the total reliability ΣR has been completed for all the runway candidate lines. If there is a runway candidate line for which the total reliability ΣR has not been calculated, the ECU 12 returns the process to step S711. On the other hand, if the ECU 12 determines that the total reliability ΣR of all the runway candidate lines has been calculated, the process proceeds to step S72 in FIG.

  Returning to the description of FIG. 12, in step S72, the ECU 12 selects either the left road area AL or the right road area AR. Note that the ECU 12 selects an unselected area when any area has already been selected. When the ECU 12 completes the process of step S72, the process proceeds to step S73.

  In step S73, the ECU 12 sets the runway candidate line having the highest reliability total as the reference runway candidate line in the roadside region selected in step S72. When the ECU 12 completes the process of step S73, the process proceeds to step S74.

  In step S74, the ECU 12 selects a comparison target road candidate line. Specifically, the ECU 12 selects, as the comparison target runway, the runway candidate lines in the roadside region selected in step S72 and not yet selected as the comparison target runway and the reference runway candidate line. When the ECU 12 completes the process of step S74, the process proceeds to step S75.

  In step S75, the ECU 12 determines whether or not the difference value ΔR of the total reliability ΣR is equal to or less than the difference threshold value ΔRth. The difference threshold ΔRth is an arbitrary constant stored in advance in the storage device of the ECU 12, for example, 500. If the ECU 12 determines that the difference value ΔR of the total reliability ΣR is equal to or less than the difference threshold value ΔRth, the ECU 12 advances the process to step S76. On the other hand, when the ECU 12 determines that the difference value ΔR of the total reliability ΣR is larger than the difference threshold value ΔRth, the ECU 12 proceeds with the process to step S79.

  In step S76, the ECU 12 determines whether or not the number of connections J of the reference runway candidate lines is the same as the number of connections J of the comparison target runway candidate lines. If the ECU 12 determines that the number of connections J is the same, the ECU 12 advances the process to step S77. On the other hand, if the ECU 12 determines that the number of connections J is not the same, the process proceeds to step S78.

  In step S77, the reference runway candidate line and the comparison runway candidate line having the smaller start point distance pyF are set as a new reference runway candidate line. The starting point distance py represents the Y coordinate of the starting point. That is, the ECU 12 selects a runway candidate line having a short vertical distance to the start point as the runway line. When the ECU 12 completes the process of step S76, the process proceeds to step S80.

  In step S78, the ECU 12 sets, as a new reference runway candidate line, one having a larger number of connections J between the reference runway candidate line and the comparison runway candidate line. When the ECU 12 completes the process of step S77, the process proceeds to step S80.

  In step S79, the ECU 12 sets, as a new reference runway candidate line, a reference runway candidate line or a comparative control runway candidate line that has a larger reliability total R. When the ECU 12 completes the process of step S78, the process proceeds to step S80.

In step S80, the ECU 12 determines whether or not the selection of all the runway candidate lines in the selected roadside region has been completed. If the ECU 12 determines that the selection of all runway candidate lines has been completed, the ECU 12 advances the process to step S81. On the other hand, if the ECU 12 determines that an unselected track candidate line remains in the selected roadside region, the process returns to step S74.

  In step S81, the ECU 12 determines whether or not both the left road area AL and the right road area AR have been selected in the process of step S73. If the ECU 12 determines that the left and right roadside areas have been selected, the ECU 12 proceeds to step S8 in FIG. On the other hand, if the ECU 12 determines that either the left or right roadside area has not been selected yet, the ECU 12 returns the process to step S73, and selects a track line in the roadside area that has not yet been selected.

  With reference to FIG. 14, the manner in which the route line is selected by the route line selection process will be described. In addition, FIG. 14 is a figure which shows a mode that a track line is selected by a track line selection process from the track candidate line shown in FIG.

  First, it is assumed that the right road area AR is selected in step S72. In FIG. 11, the right road side area AR includes a runway candidate line starting from the detection point P13 and having the detection point P22 as the end point, and a runway candidate line having the detection point P20 as the start point and the detection point P22 as the end point. Exists. If the difference value ΔR of the total reliability ΣR of these runway candidate lines is equal to or less than the difference threshold value ΔRth (Yes in step S75), it is determined whether or not the number of connections J is the same (step S76). Here, the number of connections of the runway candidate lines starting from the detection point P13 and starting from the detection point P22 based on the value J of the connection numbers J of the runway candidate lines starting from the detection point P20 and starting from the detection point P22. Since the value of J is larger (No in step S76), as shown in FIG. 14, the runway candidate line having the detection point P13 as the start point and the detection point P22 as the end point is selected as the right runway line. .

  Next, it is assumed that the left road area AL is selected in step S72. In FIG. 11, the left road area AL includes a runway candidate line having the detection point P1 as a start point and a detection point P6 as a termination point, and a runway candidate line having the detection point P7 as a start point and the detection point P6 as a termination point. Exists. If the difference value ΔR of the total reliability ΣR of these runway candidate lines is equal to or less than the difference threshold value ΔRth (Yes in step S75), it is determined whether or not the number of connections J is the same (step S76). Here, the connection number J of the runway candidate lines having the detection point P1 as the start point and the detection point P6 as the end point, and the connection number of the runway candidate lines having the detection point P7 as the start point and the detection point P6 as the end point Since the value of J is the same number (Yes in step S76), the route line is selected according to the position of the start point with respect to the host vehicle 100. Here, since the Y coordinate py1 of the detection point P1 is smaller than the Y coordinate py7 of the detection point P7, as shown in FIG. 14, the runway candidate line having the detection point P1 as the start point and the detection point P6 as the end point. Is selected as the left track.

  According to the above-mentioned track line selection process, when a plurality of track line candidate lines are obtained, a group of detection points that form a shape along the roadside stationary object can be obtained by uniquely selecting an appropriate track line from among them. It can be selected as a track line. Therefore, it is possible to detect a running route that accurately represents the shape of the roadside stationary object and accurately estimate the shape of the road on which the host vehicle travels based on the shape of the roadside stationary object.

  Returning to the description of FIG. 3, in step S <b> 8, the ECU 12 outputs the position and shape information of the reference road candidate line selected for each of the left and right roadside regions to the vehicle control device 50 as the position and shape information of the own vehicle traveling road. 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 vehicle IG power is off. If the ECU 12 determines that the IG power of the vehicle is off, the ECU 12 ends the process of the flowchart of FIG. On the other hand, when the ECU 12 determines that the IG power supply of the vehicle remains on, the ECU 12 returns the process to step S1 and repeats the above process.

  As described above, according to the road shape estimation device 1 according to the embodiment of the present invention, a candidate road line is uniquely selected based on a predetermined condition from a plurality of connection route lines formed by connecting detection points. Thus, a group of detection points that will form a shape along the roadside stationary object can be formed and selected. Therefore, it is possible to accurately detect the shape of the roadside stationary object and accurately estimate the shape of the road on which the host vehicle travels based on the shape of the roadside stationary object.

  The road shape estimation apparatus according to the present invention is useful as a road shape estimation apparatus that can accurately estimate the road shape.

1 Road shape estimation device 11 Radar device 12 ECU
50 Vehicle control device 100 Own vehicle

Claims (9)

A road shape estimation device that is mounted on a vehicle and estimates a shape of a road on which the vehicle travels,
An object detection unit for detecting the presence positions of roadside stationary objects around the vehicle as a plurality of detection points;
A connection path line forming unit that forms a plurality of connection path lines by sequentially connecting the detection points;
Among the plurality of connection route lines formed by the connection route line forming unit, a runway candidate selection unit that selects the connection route line satisfying a predetermined condition as a runway candidate line,
A road shape estimation device comprising: a road shape estimation unit that estimates the shape of the road based on the runway candidate line. The connection path line forming unit forms a connection path line group including a plurality of the connection path lines by sequentially connecting the detection points,
The said runway candidate selection part selects the said connection route line which satisfy | fills predetermined conditions among the said connection route lines contained in the said connection route line group as the said runway candidate line, The Claim 1 characterized by the above-mentioned. Road shape estimation device. The connection path line forming part is
A connection range setting unit that sets a connection range based on the detection point that is a connection source; and
When there are a plurality of detection points in the connection range, each of the plurality of detection points existing in the connection range is set as a connection destination, and the detection point that is the connection source and the detection point that is the connection destination are The road shape estimation apparatus according to claim 2, further comprising a route ship group forming unit that forms the connection route line group by connecting.   The runway candidate selection unit calculates the number of connections of the detection points constituting the connection path line for each connection path line, and selects the connection path line having the largest number of connections as the runway candidate line. The road shape estimation apparatus according to any one of claims 1 to 3, wherein the road shape estimation apparatus is characterized.   The said runway candidate selection part selects the said runway candidate line based on the position of the left-right direction seen from the said vehicle of the said vehicle from the said detection point which comprises the said connection route line. 5. The road shape estimation apparatus according to any one of 4 above.   The said runway candidate selection part selects the said connection route line containing the said detection point with the position of the left-right direction seen from the said vehicle nearest to the said vehicle as said runway candidate line, It is characterized by the above-mentioned. Road shape estimation device. Further comprising a start point selection unit for selecting a plurality of start points from the plurality of detection points;
The connection route line forming unit forms a plurality of the connection route line groups for each start point by sequentially connecting the detection points from the start point,
The runway candidate selection unit selects a plurality of the runway candidate lines for each of the plurality of connection route line groups,
The road shape estimation device further includes a runway line selection unit that selects a runway candidate line that satisfies a predetermined condition among the plurality of runway candidate lines as a runway line,
The road shape estimation device according to any one of claims 2 to 6, wherein the road shape estimation unit estimates the shape of the road based on the running route.   The said runway line selection part selects the said runway candidate line containing the said starting point with the position of the front-back direction seen from the said vehicle nearest to the said vehicle as the said runway line, The characterized by the above-mentioned. Road shape estimation device. Based on the information on the past detection points stored in the storage unit, further includes an extrapolation processing unit that extrapolates the present position of the past detection points as the detection points,
The runway line selection unit has a reliability indicating a high possibility that the runway candidate line is a roadside stationary object arranged along the road, and the detection points constituting the runway candidate line are extrapolation points. It calculates for every said runway candidate line according to whether it is or, and based on the magnitude | size of the said reliability, either of the said runway candidate lines is selected as said runway line, It is characterized by the above-mentioned. The road shape estimation apparatus according to any one of 8.

Images