Travel route generation device and travel route generation method

Abstract

To generate a travel route which can realize a safe and smooth vehicle behavior on the basis of a traffic lane center point line acquired from map information and image information.SOLUTION: A travel route generation device generates a traffic lane center point line based on boundary line information, divides the traffic lane center point line into a plurality of sections, generates a travel route as a curve passing through a plurality of control points provided at positions corresponding to traffic lane center points on both ends of the sections, divides a maximum error section in each section of the travel route sectioned by the control points into two sections when the matching degree between the travel route and the traffic lane center point line is equal to or less than a threshold, generates the travel route as a curve passing through the control points provided at positions corresponding to the traffic lane center point on both ends of the divided sections, and repeats the division of the maximum error section and the generation of the travel route until the matching degree becomes larger than the threshold. The curve of each section of the travel route is expressed by a quintic function, and the quintic function is determined such that a tangent vector and a curvature vector continue at each control point.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a driving route generation device and a driving route generation method for generating a driving route for a vehicle. [Background technology]

[0002] Conventionally, technologies have been developed that set a driving route for a vehicle to travel based on the circumstances around the vehicle and the state of the vehicle, and perform driving assistance for the vehicle (specifically, driving assist control or automatic driving control) based on this driving route. For example, Patent Documents 1 and 2 disclose technologies that generate a vehicle's driving trajectory or driving route using a cubic function or a clothoid curve. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 6739881 Specification [Patent Document 2] Patent Publication No. 2021-160625 Summary of the Invention [Problem to be solved by the invention]

[0004] Generally, to allow a vehicle to safely travel within a lane, a driving route is generated along a virtual center line (lane center line) located in the center of the lane in the width direction. The lane center line is acquired as a sequence of points at the center of the lane detected based on, for example, position information of boundary lines (e.g., road dividing lines and road edges) included in map information or image information of boundary lines recognized by an on-board camera. The driving route is generated so as to follow this sequence of lane center points.

[0005] If the position information or image information of road boundary lines contains noise, or if the boundary lines themselves contain discontinuities (such as intersections, forks, or points where lane widths change), the lane center point sequence generated based on that position information and image information will also contain points with noise or large displacements. In this case, to ensure smooth vehicle travel, it is necessary to generate a driving path by smoothing the lane center point sequence. However, using a moving average or B-spline curve, for example, would smooth not only the noise but also the displacement of the lane center point sequence, which reflects the shape of the lane, and the generated driving path may not follow the actual shape of the lane. On the other hand, it is possible to generate a driving path using an interpolated curve or approximate curve that follows all points in the lane center point sequence. However, in this case, the noise and discontinuities will be reflected in the driving path, which may cause discomfort to occupants when vehicle driving assistance is provided based on that driving path.

[0006] The present invention has been made to solve the above-mentioned problems, and aims to provide a driving route generation device and a driving route generation method that can generate a driving route that can achieve safe and smooth vehicle behavior based on a sequence of lane center points obtained from map information and image information. [Means for solving the problem]

[0007] In order to achieve the above object, the present invention provides a driving route generation device that generates a driving route for a vehicle, the driving route generation device comprising: a boundary line information acquisition device that acquires boundary line information for identifying the boundary lines of the lane on which the vehicle is traveling; and a calculation device configured to generate a driving route based on the boundary line information, the calculation device generating a sequence of lane center points aligned along the center of the lane in the width direction based on the boundary line information, dividing the sequence of lane center points into a plurality of sections, generating a driving route as a curve passing through a plurality of control points provided at positions corresponding to the lane center points at both ends of each section, and calculating a degree of coincidence between the generated driving route and the sequence of lane center points. If the degree of agreement is equal to or less than a threshold, the maximum error section, within each section of the travel route divided by the control points, where the sum of the squares of the residuals from the sequence of lane center points within that section is the largest, is divided into two sections, and a travel route is generated as a curve that further passes through control points located at positions corresponding to the lane center points at both ends of each divided section. The division of the maximum error section and the generation of the travel route are repeated until the degree of agreement becomes greater than the threshold, and the curve of each section of the travel route is represented by a quintic function, and the quintic function is determined so that the tangent vector and curvature vector of the curve are continuous at the control points that divide each section. In the present invention configured as described above, the calculation device represents the curve of each section that constitutes the driving route using a quintic function and determines the coefficients of the quintic function that represents the curve of each section so that the tangent vector of the curve at the control points that form the boundary of each section and the curvature vector obtained by differentiating the tangent vector are continuous, thereby making it possible to generate a driving route that ensures smooth vehicle behavior at each control point.In addition, by repeating the division of the section with the largest error and the generation of driving routes until the degree of match exceeds a threshold, it is possible to generate a safe driving route that follows the actual shape of the lane on which the vehicle 1 will travel.

[0008] In the present invention, the boundary line information acquisition device is preferably a camera, and acquires image information including images of road dividing lines and road edges as boundary line information. According to the present invention configured as described above, it is possible to generate a driving route that enables safe and smooth vehicle behavior to be achieved based on image information acquired by the camera.

[0009] In the present invention, the boundary line information acquisition device is preferably a navigation system, and acquires map information including the positions of road dividing lines and road edges as boundary line information. According to the present invention configured as described above, it is possible to generate a driving route that allows safe and smooth vehicle behavior to be achieved based on map information acquired by the navigation system.

[0010] In the present invention, the calculation device preferably calculates a coefficient of determination adjusted for degrees of freedom as the degree of agreement. According to the present invention configured as described above, it is possible to determine the degree of coincidence between a travel route and a sequence of lane center points without using a specific physical quantity (for example, distance) as a threshold value.

[0011] In another aspect, the present invention provides a driving route generation method, which uses a computing device to generate a driving route for a vehicle to travel, in which the computing device acquires boundary line information for identifying boundary lines of a lane along which the vehicle is traveling, generates a sequence of lane center points aligned along the center of the lane in the width direction based on the boundary line information, divides the sequence of lane center points into a plurality of sections, generates a driving route as a curve passing through a plurality of control points provided at positions corresponding to the lane center points at both ends of each section, calculates a degree of coincidence between the generated driving route and the sequence of lane center points, and if the degree of coincidence is equal to or less than a threshold, generates a driving route as a curve passing through a plurality of control points provided ... and calculates a degree of coincidence between the generated driving route and the sequence of lane center points. In this case, among each section of the travel route divided by control points, the maximum error section where the sum of squares of the residuals from the sequence of lane center points within that section is the largest is divided into two sections, and a travel route is generated as a curve that further passes through control points located at positions corresponding to the lane center points at both ends of each divided section.The division of the maximum error section and the generation of the travel route are repeated until the degree of match becomes greater than a threshold, and the curve of each section of the travel route is represented by a quintic function, and the quintic function is determined so that the tangent vector and curvature vector of the curve are continuous at the control points that divide each section. [Effects of the Invention]

[0012] According to the driving route generation device and driving route generation method of the present invention, a driving route that can achieve safe and smooth vehicle behavior can be generated based on a sequence of lane center points obtained from map information or image information. [Brief explanation of the drawings]

[0013] [Figure 1] 1 is a system block diagram showing a schematic configuration of a vehicle driving assistance system to which a driving route generation device according to an embodiment of the present invention is applied. [Figure 2] FIG. 2 is an explanatory diagram illustrating input and output of a driving route generation device according to an embodiment of the present invention. [Figure 3] 3 is a flowchart of a driving route generation process executed by a driving route generation device according to an embodiment of the present invention. [Figure 4] 1 is an explanatory diagram illustrating a sequence of lane center points and a driving route generated by a driving route generation device according to an embodiment of the present invention; [Figure 5] 1 is a diagram illustrating an example of a driving route generated by a driving route generation device according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0014] Hereinafter, a driving route generation device and a driving route generation method according to an embodiment of the present invention will be described with reference to the accompanying drawings.

[0015] [System Configuration] First, the configuration of a vehicle driving assistance system to which a driving route generation device according to an embodiment of the present invention is applied will be described with reference to Fig. 1. Fig. 1 is a block diagram showing a schematic configuration of a vehicle driving assistance system to which a driving route generation device according to an embodiment of the present invention is applied.

[0016] The vehicle driving assistance system 100 has a function as a driving route generation device that generates a driving route for the vehicle 1 to travel based on map information and image information, and is configured to perform driving assistance control (driving assist control and automatic driving control) so that the vehicle 1 travels along this driving route. As shown in Fig. 1, the vehicle driving assistance system 100 has an ECU (Electronic Control Unit) 10 as a calculation device and a control device, a plurality of sensors, and a plurality of control systems.

[0017] Specifically, the multiple sensors include a camera 21, a radar 22, and a vehicle speed sensor 23, an acceleration sensor 24, a yaw rate sensor 25, a steering angle sensor 26, an accelerator sensor 27, and a brake sensor 28 for detecting the behavior of the vehicle 1 and driving operations by the occupants. Furthermore, the multiple sensors include a positioning system 29 and a navigation system 30 for detecting the position of the vehicle 1. The multiple control systems include a driving force control system 31, a brake control system 32, and a steering control system 33.

[0018] Other sensors may include a peripheral sonar that measures the distance and position of surrounding structures relative to vehicle 1, a corner radar that measures the approach of surrounding structures at the four corners of vehicle 1, and an inner camera that photographs the interior of vehicle 1.

[0019] The ECU 10 performs various calculations based on signals received from a plurality of sensors, and transmits control signals to a driving force control system 31, a brake control system 32, and a steering control system 33 to appropriately operate the engine system, the brake system, and the steering system, respectively. The ECU 10 is configured by a computer equipped with one or more processors (typically a CPU), memory (ROM, RAM, etc.) for storing various programs, input / output devices, etc. The ECU 10 corresponds to an example of the "calculation device" in the present invention.

[0020] The camera 21 captures images of the surroundings of the vehicle 1 and outputs image information. The ECU 10 identifies objects (for example, dividing lines (lane boundaries, white lines, yellow lines, etc.), road edges, stop lines, traffic signals, traffic signs, intersections, obstacles, leading vehicles (vehicles ahead), following vehicles (vehicles behind), parked vehicles, pedestrians, etc.) based on the image information received from the camera 21. The ECU 10 may obtain information about objects from an external source, such as through traffic infrastructure or vehicle-to-vehicle communication. This allows the type, relative position, moving direction, etc. of the object to be identified.

[0021] The camera 21 corresponds to an example of a "boundary line information acquisition device" in the present invention. The "boundary line information" is information for identifying the boundary line of the lane in which the vehicle 1 is traveling, and includes, for example, information on division lines, road edges, etc.

[0022] The radar 22 measures the position and speed of an object (particularly, a preceding vehicle, a following vehicle, a parked vehicle, a pedestrian, an object fallen on the road, etc.). For example, a millimeter wave radar can be used as the radar 22. Note that instead of the radar 22, a laser radar, an ultrasonic sensor, etc. may be used.

[0023] The vehicle speed sensor 23 detects the absolute speed of the vehicle 1. The acceleration sensor 24 detects the acceleration of the vehicle 1. This acceleration includes acceleration in the longitudinal direction and acceleration in the lateral direction (i.e., lateral acceleration). Note that the acceleration includes not only the rate of change of speed in the direction in which the speed increases, but also the rate of change of speed in the direction in which the speed decreases (i.e., deceleration).

[0024] The yaw rate sensor 25 detects the yaw rate of the vehicle 1. The steering angle sensor 26 detects the rotation angle (steering angle) of the steering wheel of the vehicle 1. The ECU 10 can obtain the yaw rate of the vehicle 1 by performing a predetermined calculation based on the absolute speed detected by the vehicle speed sensor 23 and the steering angle detected by the steering angle sensor 26. The accelerator sensor 27 detects the amount of depression of the accelerator pedal. The brake sensor 28 detects the amount of depression of the brake pedal.

[0025] The positioning system 29 is a GPS system and / or a gyro system, and detects the position of the vehicle 1 (current vehicle position information). The navigation system (navigation system) 30 provides the ECU 10 with map information stored internally and / or map information acquired from an external source. The ECU 10 identifies roads, intersections, traffic signals, buildings, etc. that exist around the vehicle 1 (particularly in the direction of travel) based on the map information and the current vehicle position information. The navigation system 30 also corresponds to an example of the "boundary information acquisition device" in the present invention.

[0026] The driving force control system 31 controls the driving force source (for example, an engine or an electric motor) of the vehicle 1. The driving force control system 31 includes, for example, an engine spark plug, a fuel injection valve, a throttle valve, a variable valve mechanism that changes the opening and closing timing of the intake and exhaust valves, an inverter that controls the power supplied to the electric motor, etc. When it is necessary to accelerate or decelerate the vehicle 1, the ECU 10 sends a control signal to the driving force control system 31 to change the output.

[0027] The brake control system 32 controls the brake device of the vehicle 1. The brake control system 32 is a component that can adjust the braking force of the brake device, and includes, for example, a hydraulic pump, a valve unit, etc. When it is necessary to decelerate the vehicle 1, the ECU 10 sends a control signal to the brake control system 32 to generate braking force.

[0028] The steering control system 33 controls the steering device of the vehicle 1. The steering control system 33 is a component that can adjust the steering angle of the vehicle 1, and includes, for example, an electric motor of an electric power steering system. When it is necessary to change the traveling direction of the vehicle 1, the ECU 10 transmits a control signal to the steering control system 33 to change the steering direction.

[0029] [Input / output of the driving path generation device] Next, input and output of the driving route generation device according to the embodiment of the present invention will be described with reference to Fig. 2. Fig. 2 is an explanatory diagram showing input and output of the driving route generation device. Specifically, Fig. 2 shows that the ECU 10 processes information input from sensors and outputs driving route information to the control system.

[0030] The sensors continuously transmit the acquired information to the ECU 10. The ECU 10 performs the following calculations based on the acquired information.

[0031] The ECU 10 calculates the position and azimuth of the vehicle 1 based on the position information from the positioning system 29 , the vehicle speed information from the vehicle speed sensor 23 , and the yaw rate information from the yaw rate sensor 25 .

[0032] Furthermore, the ECU 10 identifies the boundary lines of the lane in which the vehicle 1 is traveling, based on map information from the navigation system 30 and the calculated position and azimuth of the vehicle 1. Furthermore, the ECU 10 identifies the boundary lines of the lane in which the vehicle 1 is traveling, based on image information from the camera 21. These boundary lines are identified, for example, by expressing the position of each point of a sequence of points (sequence of boundary line points) arranged at a predetermined interval (for example, 0.5 m) on the boundary line, in coordinates in a coordinate system based on the vehicle 1 (vehicle-referenced coordinate system), and are identified up to a predetermined distance (for example, 100 m) ahead in the traveling direction from the current position of the vehicle 1.

[0033] Furthermore, ECU 10 generates a sequence of points on lane center lines (a sequence of lane center points) based on either lane boundary lines identified based on map information and the position and azimuth of vehicle 1, or lane boundary lines identified based on image information. The sequence of lane center points is generated as coordinates in a vehicle-referenced coordinate system representing the positions of each point in the sequence of points arranged at predetermined intervals (e.g., 0.5 m) on the lane center line (e.g., a line connecting the midpoints between the boundary lines located on the left and right sides of vehicle 1), and is generated from the current position of vehicle 1 to a predetermined distance (e.g., 100 m) ahead in the traveling direction.

[0034] Furthermore, the ECU 10 generates a driving route based on the generated sequence of lane center points. The ECU 10 sets a plurality of control points based on the sequence of lane center points, and calculates a curve function that satisfies the constraints defined by the control points, thereby generating the driving route.

[0035] Furthermore, the ECU 10 calculates the degree of coincidence between the generated driving route and the sequence of lane center points based on the generated driving route and the sequence of lane center points. If the calculated degree of coincidence is equal to or less than a predetermined threshold, the ECU 10 adds control points based on the sequence of lane center points and generates a new driving route based on the multiple control points including the added control points. If the calculated degree of coincidence is greater than the predetermined threshold, the ECU 10 confirms the driving route and outputs driving route information related to the confirmed driving route to the control system. The control system executes driving assistance control based on the driving route information to cause the vehicle 1 to travel along the driving route.

[0036] [Route generation process] Next, a flow of a driving route generation process executed by a driving route generation device according to an embodiment of the present invention will be described with reference to Figures 3 and 4. Figure 3 is a flowchart of the driving route generation process, and Figure 4 is an explanatory diagram illustrating an example of a sequence of lane center points and a driving route generated by the driving route generation device. For example, after the ignition switch of the vehicle 1 is turned on and a request to execute driving assistance control is received, the ECU 10 repeatedly executes the driving route generation process at a predetermined cycle (for example, every 0.05 to 0.2 seconds).

[0037] First, in step S1, the ECU 10 acquires various pieces of information from the multiple sensors shown in FIG. 1 (particularly, the camera 21, the positioning system 29, the navigation system 30, etc.).

[0038] Next, in step S2, the ECU 10 calculates the vehicle position (for example, latitude and longitude) and azimuth angle based on the position information, vehicle speed information, yaw rate information, etc. acquired in step S1.

[0039] Next, in step S3, the ECU 10 determines whether the map information acquired in step S1 includes information on a high-precision map. Here, a high-precision map is one in which the accuracy of position information of objects (particularly lane lines and road edges) included in the map is centimeter-level or higher.

[0040] If the map information includes high-precision map information (step S3: YES), the process proceeds to step S4, where the ECU 10 searches the high-precision map for a sequence of boundary line points around the vehicle that includes a predetermined distance (e.g., 100 m) ahead of the vehicle position in the traveling direction, based on the vehicle position and azimuth angle calculated in step S2.

[0041] Also, if the map information does not include high-precision map information (step S3: NO), the process proceeds to step S5, where ECU 10 uses known image analysis technology to detect white lines around the vehicle, including a predetermined distance (e.g., 100 m) ahead of the vehicle's position in the direction of travel, from the image information acquired in step S1.

[0042] Next, in step S6, the ECU 10 generates a sequence of boundary line points around the vehicle based on the white lines detected in step S5. As the sequence of boundary line points, the ECU 10 can use, for example, the sequence of points on the white lines detected in step S5 as is, or can use the sequence of points after applying a predetermined smoothing process to the sequence of points on the white lines.

[0043] After step S4 or S6, in step S7, the ECU 10 generates a sequence of lane center points based on the sequence of boundary line points searched in step S4 or the sequence of boundary line points generated in step S6. For example, the ECU 10 generates, as the sequence of lane center points, a sequence of midpoints between the boundary lines on both the left and right sides of the vehicle, which are represented by the sequence of boundary line points at a predetermined distance (e.g., 100 m) ahead from the vehicle position in the traveling direction.

[0044] Next, in step S8, the ECU 10 divides the sequence of lane center points generated in step S7 into two sections. For example, as shown in Fig. 4, the ECU 10 selects lane center points that are the boundaries between the two sections so that the number of lane center points included in each of the two sections is equal.

[0045] Next, in step S9, ECU 10 generates a driving route based on the sequence of lane center points generated in step S7. As shown in FIG. 4, the driving route is represented as a curve that passes through a plurality of control points. The control points are provided at positions corresponding to the lane center points at both ends of each section divided in step S8 and step S13 (described later), and each curve connecting adjacent control points is represented by a quintic function. By determining the coefficients of the quintic function that represents the curve of each section so that the tangent vector of the curve at the control point that forms the boundary of each section and the curvature vector obtained by differentiating the tangent vector are continuous, a driving route is generated that ensures smooth vehicle behavior when passing through each control point.

[0046] The derivation of the quintic function that represents the curve of each section that constitutes the travel route will be explained below. In a vehicle-based coordinate system with orthogonal x- and y-axes, the tangent vector dy / dx at (x0, y0) passes through two points (x0, y0) and (x1, y1), and the curvature vector d 2 y / dx 2 is κ0, the tangent vector dy / dx at (x1,y1) is θ1, and the curvature vector d 2 y / dx 2 The quintic function of the curve with κ1 is expressed as follows:

[0047] TIFF0007752831000001.tif4087...Formula (1)

[0048] where: The file is TIFF0007752831000002.tif141111.

[0049] ECU10 determines a quintic function representing the curve of each section of the driving route (i.e., generates a driving route) by optimizing each section and the entire route so that the sum of squares J of the residuals between the curve of each section and the sequence of lane center points within that section is minimized, under the constraint that the tangent vector and curvature vector of the curve of each section expressed by the above formula (1) are continuous (i.e., have the same value) at the control points that form the boundary of each section.

[0050] Focusing on the x-coordinate, the sum of squares of the residuals is expressed by the following equation using the parameter t: TIFF0007752831000003.tif1859...(2) where i is the number of control points (i.e., the number of sections + 1), and p i , q i represent the first lane center point and the last lane center point included in each section, respectively. Also, S i (t k ) is a quintic function that expresses x using the parameter t. TIFF0007752831000004.tif9167...(3) is.

[0051] The Lagrange multiplier method is used to calculate the sum of squares of the residuals J under the constraint that the coefficients at the control points that form the boundaries of each interval are consistent. x A normal equation is obtained that gives the minimum value of (i.e., the partial derivative of each parameter is set to 0). By solving this equation, a quintic function that represents the curve of each section is obtained. For the control point at the end point of the last section, other parameters (i.e., y coordinate, tangent vector, curvature vector) can be determined by, for example, setting the x coordinate of the control point at the end point of the last section to the x coordinate of the lane center point sequence.

[0052] Next, in step S10, the ECU 10 calculates the degree of coincidence between the sequence of lane center points generated in step S7 and the driving path generated in step S9. The ECU 10 calculates, for example, a coefficient of determination with degrees of freedom adjustment as the degree of coincidence. Alternatively, the coefficient of determination or the sum of squares of residuals may be used as the degree of coincidence.

[0053] Next, in step S11, the ECU 10 determines whether the degree of match calculated in step S10 is greater than a threshold value. The threshold value can be determined depending on the accuracy of the map information and image information, the response characteristics of the control system of the vehicle 1, and the like. For example, when a degree-of-freedom-adjusted coefficient of determination is used as the degree of match, the threshold value can be a value between 0 and 1, for example, 0.8.

[0054] If the degree of match is greater than the threshold in step S11, the process proceeds to step S12, where ECU 10 finally determines the driving route generated in step S9 as the driving route to be ultimately used, and outputs driving route information including information about the driving route (for example, a quintic function representing the curves of each section that makes up the driving route) to the control system.

[0055] On the other hand, if the degree of match is equal to or less than the threshold in step S11, the process proceeds to step S13, where the ECU 10 divides the section (maximum error section) that has the largest error (the largest sum of squares of the residuals from the lane center point sequence within the section) into two sections. For example, the ECU 10 selects lane center points that are the boundary between the two sections so that the number of lane center points included in each of the two sections after division is equal.

[0056] Next, returning to step S9, ECU 10 generates a travel route by determining again the coefficients of the quintic function that represents the curve of each section so that the tangent vectors of the curve at the control points that form the boundaries of each section, including the divided sections, and the curvature vectors obtained by differentiating the tangent vectors are continuous. Thereafter, ECU 10 repeats steps S9 to S11 and S13 until it is determined in step S11 that the degree of match is greater than the threshold value.

[0057] [Action and effect] Next, the operation and effects of the embodiment of the present invention will be described.

[0058] Fig. 5 is a diagram showing an example of a driving route generated by a driving route generation device according to an embodiment of the present invention. In Fig. 5, solid lines indicate lines connecting sequences of lane center points, dotted lines indicate driving routes generated by conventional technology, and dashed lines indicate driving routes generated by this embodiment. Fig. 5(b) is an enlarged view of the range from x=100 to x=150 in Fig. 5(a), and Fig. 5(c) is an enlarged view of the range from x=140 to x=190 in Fig. 5(a).

[0059] As is clear from Figure 5, in the embodiment of the present invention, a driving path is generated that more closely matches the lane centerline compared to the comparative example, regardless of whether the lane centerline is straight or sharply curved. Furthermore, particularly with reference to the range of x = 120 to 150 in Figure 5(b), it can be seen that the curvature of the driving path changes more smoothly in the embodiment compared to the comparative example. In other words, when vehicle 1 is driven along the driving path in the embodiment, the behavior of vehicle 1 can be made smoother compared to the comparative example.

[0060] In this embodiment, the ECU 10 generates a sequence of lane center points based on boundary information acquired from the camera 21, the navigation system 30, or the like, divides the sequence of lane center points into multiple sections, and generates a driving route as a curved line passing through multiple control points located at positions corresponding to the lane center points at both ends of each section. If the degree of match between the generated driving route and the sequence of lane center points is equal to or less than a threshold, the ECU 10 divides each section of the driving route divided by the control points into two sections, where the maximum error section has the largest sum of squared residuals from the sequence of lane center points within that section. The ECU 10 then generates a driving route as a curved line passing through control points located at positions corresponding to the lane center points at both ends of each divided section. The ECU 10 repeats dividing the maximum error section and generating the driving route until the degree of match exceeds the threshold. The ECU 10 also determines the quintic function so that the curve of each section of the driving route is represented by a quintic function and the tangent vector and curvature vector of the curve are continuous at the control points that divide each section. In this way, the curve of each section constituting the driving route is represented by a quintic function, and the coefficients of the quintic function representing the curve of each section are determined so that the tangent vector of the curve at the control points forming the boundary of each section and the curvature vector obtained by differentiating the tangent vector are continuous, making it possible to generate a driving route that ensures smooth behavior of vehicle 1 at each control point.In addition, since the division of the section with the maximum error and the generation of driving routes are repeated until the degree of match exceeds a threshold, it is possible to generate a safe driving route that follows the actual shape of the lane on which vehicle 1 will travel.

[0061] In this embodiment, the boundary line information acquisition device is the camera 21, which acquires image information including images of road dividing lines and road edges as boundary line information. Therefore, based on the image information acquired by the camera 21, a driving route that enables safe and smooth vehicle behavior to be generated.

[0062] In this embodiment, the boundary line information acquisition device is the navigation system 30, which acquires map information including the positions of road dividing lines and road edges as boundary line information. Therefore, based on the map information acquired by the navigation system 30, a driving route that enables safe and smooth vehicle behavior can be generated.

[0063] In this embodiment, the ECU 10 calculates the degree of coincidence as a coefficient of determination adjusted for the degrees of freedom, and can therefore determine the degree of coincidence between the travel path and the sequence of lane center points without using a specific physical quantity (e.g., distance) as a threshold. [Explanation of symbols]

[0064] 1 vehicle 10 ECU 21 Camera 29 Positioning System 30 Navigation System 31 Driving Force Control System 32 Brake Control System 33 Steering Control System 100 Vehicle driving assistance system (driving route generation device)

Claims

1. A driving route generation device that generates a driving route for a vehicle, a boundary line information acquisition device that acquires boundary line information for identifying a boundary line of a lane on which the vehicle is traveling; a computing device configured to generate the travel route based on the boundary information, The computing device generating a sequence of lane center points aligned along the center of the lane in the width direction based on the boundary line information; Dividing the sequence of lane center points into a plurality of sections; generating the driving route as a curve passing through a plurality of control points provided at positions corresponding to lane center points at both ends of each of the sections; calculating a degree of coincidence between the generated travel route and the sequence of lane center points; If the degree of agreement is equal to or less than a threshold, among each section of the travel route divided by the control points, a maximum error section in which the sum of squares of residuals from the sequence of lane center points within that section is maximum is divided into two sections, and the travel route is generated as a curve that further passes through control points provided at positions corresponding to the lane center points at both ends of each of the divided sections, and the division of the maximum error section and the generation of the travel route are repeated until the degree of agreement becomes greater than a threshold; the curve of each section of the travel route is represented by a quintic function, and the quintic function is determined so that tangent vectors and curvature vectors of the curve are continuous at the control points that divide each section. It is configured as follows: Driving route generation device.

2. 2. The driving route generation device according to claim 1, wherein the boundary line information acquisition device is a camera, and acquires image information including images of road dividing lines and road edges as the boundary line information.

3. 2. The driving route generation device according to claim 1, wherein the boundary line information acquisition device is a navigation system, and acquires map information including road division lines and road edge positions as the boundary line information.

4. The driving route generation device according to claim 1 , wherein the calculation device calculates a degree-of-freedom adjusted coefficient of determination as the degree of coincidence.

5. A driving route generation method for generating a driving route for a vehicle by a computing device, comprising: The computing device acquiring boundary line information for identifying a boundary line of a lane in which the vehicle is traveling; generating a sequence of lane center points aligned along the center of the lane in the width direction based on the boundary line information; Dividing the sequence of lane center points into a plurality of sections; generating the driving route as a curve passing through a plurality of control points provided at positions corresponding to lane center points at both ends of each of the sections; calculating a degree of coincidence between the generated travel route and the sequence of lane center points; If the degree of agreement is equal to or less than a threshold, among each section of the travel route divided by the control points, a maximum error section in which the sum of squares of residuals from the sequence of lane center points within that section is maximum is divided into two sections, and the travel route is generated as a curve that further passes through control points provided at positions corresponding to the lane center points at both ends of each of the divided sections, and the division of the maximum error section and the generation of the travel route are repeated until the degree of agreement becomes greater than a threshold; the curve of each section of the travel route is represented by a quintic function, and the quintic function is determined so that tangent vectors and curvature vectors of the curve are continuous at the control points that divide each section. A driving route generation method.

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