Path generation device and path generation method

Abstract

The path generation device (100) includes a passing point setting section (13) that sets a target passing point on a travel lane at the time of travel of a host vehicle (1), a path generation section (14) that generates a target travel path from a current point to the target passing point set by the passing point setting section (13), and a speed information acquisition section that acquires speed information of the host vehicle (1). The passing point setting section (13) sets a target passing point after a prescribed time when the travel speed of the host vehicle (1) is equal to or higher than a prescribed value, and sets the target passing point at a prescribed distance from the current point when the travel speed of the host vehicle (1) is lower than the prescribed value, based on the speed information acquired by the speed information acquisition section.

Description

TECHNICAL FIELD

[0001] The present application relates to a path generating device and a path generating method that generate a target travel path of a host vehicle having an automatic driving function and a driving assistance function. BACKGROUND

[0002] In the past, a device that generates a target travel path of an automatic driving vehicle is known (see, for example, Patent Literature 1). In the device described in Patent Literature 1, a target passing point through which the host vehicle should pass at a prescribed time is set, and a passing point per unit time is set between the current point and the target passing point, and the target travel path is generated by sequentially connecting each passing point.

[0003] By popularizing vehicles having an automatic driving function and a driving assistance function, it is possible to improve the safety and convenience of the entire traffic society and realize a sustainable transport system. In addition, by improving the efficiency and smoothness of transport, it is possible to reduce CO2 emissions and reduce environmental load.

[0004] However, if the target travel path from the current point to the target passing point after the prescribed time is generated as in the device described in Patent Literature 1, the target passing point will be too close to the current point in the case where the vehicle speed is reduced due to congestion or the like, and it will be difficult to generate an appropriate target travel path.

[0005] PRIOR ART DOCUMENTS

[0006] PATENT LITERATURE

[0007] Patent Literature 1: Japanese Patent Application Publication No. 2019-086038 (JP 2019-086038 A). SUMMARY

[0008] The path generating device according to one aspect of the present application includes a passing point setting section that sets a target passing point on a travel lane at the time of travel of a host vehicle, a path generating section that generates a target travel path from a current point to the target passing point set by the passing point setting section, and a speed information acquiring section that acquires speed information of the host vehicle. The passing point setting section sets the target passing point after a prescribed time in accordance with the speed information acquired by the speed information acquiring section when the travel speed of the host vehicle is equal to or greater than a prescribed value, and sets the target passing point at a prescribed distance from the current point when the travel speed of the host vehicle is less than the prescribed value.

[0009] Another aspect of the application is a path generation method for generating a target travel path of a host vehicle, including: setting a target passing point on a travel lane at which the host vehicle travels, generating a target travel path from a current point to the target passing point, and acquiring speed information of the host vehicle. The setting of the target passing point includes: setting the target passing point after a prescribed time when the speed of the host vehicle is equal to or higher than a prescribed value, and setting the target passing point at a prescribed distance from the current point when the speed of the host vehicle is lower than the prescribed value. BRIEF DESCRIPTION OF DRAWINGS

[0010] The objects, features and advantages of the present application will be made clearer by the following description of the embodiments with reference to the accompanying drawings.

[0011] Figure 1 is a diagram for explaining a target travel path.

[0012] Figure 2A is a diagram for explaining a change in a target travel path generated in high-speed travel.

[0013] Figure 2B is a diagram for explaining a change in a target travel path generated in low-speed travel.

[0014] Figure 3A is a diagram for explaining a target travel path generated in high-speed travel.

[0015] Figure 3B is a diagram for explaining a target travel path generated in low-speed travel.

[0016] Figure 4 is a block diagram schematically showing an example of a main part configuration and a processing flow of a path generation device of an embodiment of the present application.

[0017] Figure 5 is a diagram for explaining a cubic function representing a center line of a travel lane derived from a recognition result of a front recognition section according to Figure 4

[0018] Figure 6 is a diagram for explaining a target passing point set by a passing point setting section of Figure 4

[0019] Figure 7 is a diagram for explaining a change in a target travel path generated in low-speed travel by a path generation section of Figure 4

[0020] Figure 8 is a diagram for explaining a target travel path generated in low-speed travel by a path generation section of Figure 4 ​​​​

[0021] Figure 9A is a diagram for explaining a target travel path generated in travel on a gentle curve.

[0022] Figure 9B is a diagram for explaining a target travel path generated in travel on a sharp curve. DETAILED DESCRIPTION

[0023] Hereinafter, referring to Figures 1-9B An embodiment of the present application will be described. The path generation device of the embodiment of the present application is applied to a vehicle having a driving assistance function that controls a travel actuator to perform driving assistance for a driver of the vehicle or to automatically drive the vehicle. The "driving assistance" in the present embodiment includes driving assistance that assists a driving operation of the driver and automatic driving that automatically drives the vehicle regardless of the driving operation of the driver, and corresponds to Level 1 to Level 4 automatic driving defined by SAE, and the "automatic driving" corresponds to Level 5 automatic driving.

[0024] Figure 1 is a diagram for explaining a target travel path, showing an example of a travel scene in which the host vehicle 1 travels along the center line 2C of the travel lane 2. The target travel path 3 is generated based on a recognition result of the travel lane 2 and a surrounding vehicle 4 and the like ahead of the vehicle by a camera or the like, and the host vehicle 1 is controlled to travel along the generated target travel path 3. In Figure 1 In the example of

[0025] The target travel path 3 is generated by connecting, in time series, the passage points Pm of every unit time Δt (for example, 0.1 seconds) from the current location O of the host vehicle 1 to the target passage point Pt that should be passed at a predetermined prediction time tp (for example, about 3.1 seconds) from the current time. The target travel path 3 is updated at a predetermined period.

[0026] Figure 2A is a diagram for explaining a change in the target travel path 3 generated in high-speed travel, Figure 2B is a diagram for explaining a change in the target travel path 3 generated in low-speed travel. In addition, Figure 3A is a diagram for explaining the target travel path 3 generated in high-speed travel, Figure 3B is a diagram for explaining the target travel path 3 generated in low-speed travel.

[0027] As Figures 2A-3BAs shown, if the prediction time tp is constant, the prediction distance Xp to the travel position after the prediction time tp varies depending on the travel speed (vehicle speed) V of the host vehicle 1. In this case, the higher the speed, the farther the target passing point Pt is set, thereby enabling generation of an appropriate target travel path 3 corresponding to the vehicle speed V, but in the case where the vehicle speed V is significantly reduced due to congestion or the like, the target passing point Pt is too close to the current position O, making it difficult to generate an appropriate target travel path 3.

[0028] In Figure 2A and Figure 2B , the target travel path 3 is generated in such a manner as to follow the preceding vehicle 4a based on the recognition result of the preceding vehicle 4a traveling ahead of the host vehicle 1 on the travel lane 2. In this case, when the preceding vehicle 4a to be followed by the host vehicle 1 moves in the vehicle width direction, the target passing point Pt moves in the vehicle width direction (Pt1→Pt2), the target travel path 3 is changed and updated, and the host vehicle 1 is controlled to turn along the updated target travel path 3.

[0029] In particular, as shown in Figure 2B , in the case where the host vehicle 1 is at an extremely low speed (for example, less than 10 km / h), the prediction distance Xp becomes extremely short, and the variation (turning angle θ) of the travel direction required for the movement amount of the target passing point Pt becomes extremely large. As shown in Figure 1 , in the travel scenario where the host vehicle 1 travels along the center line 2C of the travel lane 2, such an adverse situation also occurs in the case where the left and right road markings 2L, 2R are not smooth or the like.

[0030] In Figure 3A and Figure 3B , a parallel vehicle 4b approaching the travel road of the host vehicle 1 for overtaking, cutting in, crossing, or the like between the host vehicle 1 and the preceding vehicle 4a in congestion is recognized. In this case, as shown in Figure 3A , when the parallel vehicle 4b is recognized within the prediction distance Xp, in order to alleviate the feeling of unease of the occupant, the target travel path 3 is generated so as to be offset in the direction away from the parallel vehicle 4b based on the recognition result. On the other hand, as shown in Figure 3B , in the case where the parallel vehicle 4b is recognized beyond the prediction distance Xp, it is not possible to generate the target travel path 3 taking into account the parallel vehicle 4b approaching the travel road of the host vehicle 1.

[0031] Therefore, in the present embodiment, the path generation device is configured so as to be able to generate an appropriate target travel path 3 even at a low vehicle speed by setting an appropriate prediction distance Xp in accordance with the vehicle speed V.

[0032] Figure 4This is a block diagram that schematically illustrates an example of the main components and processing flow of a path generation apparatus (hereinafter referred to as apparatus) 100 according to an embodiment of the present invention. Figure 4 As shown, the device 100 is mainly composed of an electronic control unit (ECU) 10. The ECU 10 is a computer that includes a CPU (central processing unit) and other (processor), RAM (random access memory), ROM (read-only memory) and other storage units (memory), I / O interfaces, and other peripheral circuits. For example, the ECU 10 is configured as part of a group of multiple ECUs mounted on the vehicle 1 and controlling the operation of the vehicle 1. Figure 4 The process, for example, begins when vehicle 1 is started and ECU 10 is activated, and is repeated at a predetermined interval.

[0033] The driving actuator 5, vehicle speed sensor 6, and external sensor 7 mounted on the vehicle 1 are connected to the ECU 10. The driving actuator 5 includes a steering mechanism such as a steering gear that steers the vehicle 1. The vehicle speed sensor 6 is, for example, a wheel speed sensor that detects the rotational speed of the wheels, and detects the vehicle speed V.

[0034] External sensor 7 detects the external conditions in front of the vehicle 1, centered on the direction of travel of the vehicle 1. External sensor 7 includes a camera 8 with imaging elements such as a CCD (charge-coupled device) or CMOS (complementary metal-oxide-semiconductor) to capture images of the area in front of the vehicle 1, and a distance sensor 9 that detects the inter-vehicle distance from the vehicle 1 to the preceding vehicle 4a. The distance sensor 9 may be, for example, a millimeter-wave radar that illuminates millimeter waves (radio waves) and determines the distance and direction to an object based on the time it takes for the illuminated wave to return after hitting an object. The distance sensor 9 may also be a lidar (LiDAR) system that illuminates a laser beam and determines the distance and direction to an object based on the time it takes for the laser light to return after hitting an object.

[0035] The ECU 10 has a functional structure that includes a forward recognition unit 11, a radius of curvature calculation unit 12, a passing location setting unit 13, a path generation unit 14, and a driving control unit 15 as its arithmetic unit. That is, the arithmetic unit of the ECU 10 functions as the forward recognition unit 11, the radius of curvature calculation unit 12, the passing location setting unit 13, the path generation unit 14, and the driving control unit 15.

[0036] The front recognition unit 11 recognizes the positions of road markings, curbs, guardrails, and the like on the road ahead of the vehicle in the center of the advancing direction of the host vehicle 1 based on the signals from the external sensor 7, thereby recognizing the travel lane 2 in which the host vehicle 1 is traveling. In addition, the positions of the surrounding vehicles 4 on the road ahead of the vehicle in the center of the advancing direction of the host vehicle 1 are also recognized. A general road shape is designed using a clothoid curve in which the curvature changes at a certain ratio, and a portion of the clothoid curve corresponding to the road shape can be approximated using a higher-order function such as a cubic function.

[0037] Figure 5 is a graph for illustrating a cubic function F(X) representing the center line 2C of the travel lane 2 derived from the recognition result of the front recognition unit 11. As shown in Figure 5 , the advancing direction of the host vehicle 1 with respect to the travel lane 2 can be determined based on the recognition result of the front recognition unit 11, and a cubic function F(X) representing the center line 2C of the travel lane 2 can be derived with the current position O of the host vehicle 1 as the origin and the determined advancing direction as the X axis. That is, using a curve fitting method such as the least squares method, a cubic function F(X), F(X) of the following equations (i), (ii) that approximates the left and right road markings (or curbs, guardrails, and the like) 2L, 2R recognized by the front recognition unit 11 is derived. L (X), F R (X).

[0038] F L (X) = C 3L X 3 + C 2L X 2 + C 1L X + C 0L (i)

[0039] F R (X) = C 3R X 3 + C 2R X 2 + C 1R X + C 0R (ii)

[0040] Next, based on the cubic functions F(X), F(X) corresponding to the left and right road markings 2L, 2R, a cubic function F(X) of the following equation (iii) corresponding to the center line 2C of the travel lane 2 is derived. L (X), F R (X).

[0041] F(X) = C3X 3 + C2X 2 + C1X + C0(iii)

[0042] C3= (C 3L+C 3R ) / 2, C2 = (C 2L +C 2R ) / 2

[0043] C1 = (C 1L +C 1R ) / 2, C0 = (C 0L +C 0R ) / 2

[0044] The curvature radius calculating section 12 calculates the curvature radius R of the travel lane 2 on which the host vehicle 1 travels. For example, the curvature radius R of the center line 2C of the travel lane 2 at the travel position by the look-ahead distance Xp is calculated using the following equation (iv).

[0045] R = {1 + (3C3Xp 2 + 2C2Xp + C1) 2} 1 . 5 / (6C3Xp + 2C2) (iv)

[0046] The passing point setting section 13 sets the look-ahead distance Xp in accordance with the vehicle speed V detected by the vehicle speed sensor 6, and sets the target passing point Pt at the travel position by the look-ahead distance Xp from the current position O. Figure 6 is a diagram for explaining the setting of the target passing point Pt by the passing point setting section 13, and is a diagram for explaining the setting of the look-ahead distance Xp when the target passing point Pt is set.

[0047] As shown in Figure 6 , the passing point setting section 13 sets the distance to the travel position after the predetermined look-ahead time tp as the look-ahead distance Xp (the following equation (v)) when the vehicle speed V detected by the vehicle speed sensor 6 is equal to or greater than a predetermined value Vo (for example, about 11.6 km / h). On the other hand, the passing point setting section 13 sets a predetermined distance X0 (for example, about 10 m) as the look-ahead distance Xp (the following equation (vi)) when the vehicle speed V detected by the vehicle speed sensor 6 is less than the predetermined value Vo.

[0048] Xp = Vtp (V ≥ Vo) (v)

[0049] Xp = X0 (V < Vo) (vi)

[0050] The predetermined distance X0 is set to an average inter-vehicle distance in congestion, for example, to about twice the average vehicle length (for example, about 5 m). The passing point setting section 13 can also set the actual inter-vehicle distance from the host vehicle 1 to the preceding vehicle 4a detected by the distance sensor 9 as the predetermined distance X0.

[0051] The path generation section 14 generates a target travel path 3 from the current position O to the target passing position Pt set by the passing position setting section 13. For example, the target travel path 3 from the current position O to the target passing position Pt is generated along the center line 2C of the travel lane 2 represented by the cubic function F(X) derived from the recognition result of the front recognition section 11. In addition, when a parallel vehicle 4b approaching the subject vehicle 1 is recognized in a range within the preview distance Xp, the target travel path 3 is generated so as to be offset in a direction away from the parallel vehicle 4b, based on the recognition result.

[0052] Figure 7 is a view for explaining a change in the target travel path 3 generated by the path generation section 14 in low-speed travel. Unlike the case of Figure 2B , the preview distance Xp of the prescribed distance X0 can be ensured even at a low vehicle speed, so the variation in the travel direction (the turning angle θ) due to a change in the target travel path 3 as the target passing position Pt1, Pt2 is reached can be suppressed, so that an appropriate target travel path 3 can be generated.

[0053] Figure 8 is a view for explaining a change in the target travel path 3 generated by the path generation section 14 in low-speed travel. Unlike the case of Figure 3B , the preview distance Xp of the prescribed distance X0 can be ensured even at a low vehicle speed, so the variation in the travel direction (the turning angle θ) due to a change in the target travel path 3 as the target passing position Pt1, Pt2 is reached can be suppressed, so that an appropriate target travel path 3 can be generated.

[0054] Figure 9A is a view for explaining the target travel path 3 generated in travel on a gentle curve, Figure 9B is a view for explaining the target travel path 3 generated in travel on a sharp curve. As Figure 9A indicated, on a gentle curve or a straight road with a large radius of curvature R, the front can be easily seen, the travel lane 2 at the travel position of the set-out preview distance Xp according to the vehicle speed V can be accurately recognized, and an appropriate target passing position Pt can be set. On the other hand, as Figure 9B indicated, in a sharp curve with a small radius of curvature R, the front is difficult to see, and it can be impossible to accurately recognize the travel lane 2 at the travel position of the set-out preview distance Xp according to the vehicle speed V, so it can be impossible to set an appropriate target passing position Pt.

[0055] Therefore, the location setting unit 13 sets the prediction distance Xp based not only on the vehicle speed V detected by the vehicle speed sensor 6, but also on the radius of curvature R calculated by the radius of curvature calculation unit 12, and sets the target passing point Pt. More specifically, referring to the characteristics of the storage unit pre-stored in the ECU 10, the prediction distance Xp when the target passes point Pt is set based on the vehicle speed V detected by the vehicle speed sensor 6 and the radius of curvature R calculated by the radius of curvature calculation unit 12.

[0056] In this case, the prediction distance Xp at the same vehicle speed is set according to the radius of curvature R to accurately identify the range of the driving lane 2. For example, when the radius of curvature R = 100m, the prediction distance Xp is set to 50m, and when the radius of curvature R = 2000m, the prediction distance Xp is set to 150m. By setting the prediction distance Xp to the target passage point Pt according to the radius of curvature R to accurately identify the range of the driving lane 2, an appropriate target driving path 3 can be generated.

[0057] The driving control unit 15 controls the driving actuator 5 based on the target driving path 3 generated by the path generation unit 14 to provide driving assistance to the driver of the vehicle 1 or to enable the vehicle 1 to drive automatically. As a result, the vehicle 1 can travel along the appropriate target driving path 3 even at low speeds.

[0058] The following effects can be achieved by adopting this implementation method.

[0059] (1) The device 100 includes: a location setting unit 13, which sets a target passing point Pt on the driving lane 2 when the vehicle 1 is traveling; a path generation unit 14, which generates a target driving path 3 from the current location O to the target passing point Pt set by the location setting unit 13; and a vehicle speed sensor 6, which acquires the speed information of the vehicle 1. Figure 4 Based on the speed information obtained by the vehicle speed sensor 6, the location setting unit 13 sets the target passing point Pt after a prediction time tp when the vehicle speed V is above a predetermined value V0, and sets the target passing point Pt at a predetermined distance X0 from the current location O when the vehicle speed V is below the predetermined value V0. Figure 6 ).

[0060] Therefore, even at low vehicle speeds, the predicted distance Xp of the specified distance X0 can be ensured, thus suppressing the change in travel direction that accompanies the change in the target travel path 3 to reach the target passing point Pt, thereby enabling the generation of an appropriate target travel path 3. Figure 2B , Figure 7 Additionally, it can also consider the identification results of parallel vehicles 4b, etc., that are passing by vehicle 1 within a specified distance X0 from vehicle 1, and generate an appropriate target driving path 3.Figure 3B 、 Figure 8 )。

[0061] (2) The device 100 is further provided with a distance sensor 9 that detects an inter-vehicle distance D from the host vehicle 1 to a preceding vehicle 4a that travels in front of the host vehicle 1 on the travel lane 2 on which the host vehicle 1 travels. Figure 4 ) The inter-vehicle distance D detected by the distance sensor 9 is set as a prescribed distance X0 by the point setting section 13. Thereby, the target travel path 3 can be generated appropriately while taking into account the recognition result of a parallel vehicle 4b that overtakes, cuts in, or weaves between the host vehicle 1 and the preceding vehicle 4a in a traffic jam. Figure 3B 、 Figure 8 ).

[0062] (3) The device 100 is further provided with a curvature radius calculation section 12 that calculates a curvature radius R of the travel lane 2 on which the host vehicle 1 travels. Figure 4 ) The target passing point Pt is set by the point setting section 13 also in accordance with the curvature radius R calculated by the curvature radius calculation section 12. That is, by setting the foresight distance Xp to the target passing point Pt within a range in which the travel lane 2 can be recognized with high accuracy in accordance with the curvature radius R, the target travel path 3 can be generated appropriately.

[0063] (4) The device 100 is further provided with a travel control section 15 that controls the travel actuators 5, performs driving assistance to a driver of the host vehicle 1, or causes the host vehicle 1 to be driven automatically. Figure 4 ) The travel control section 15 controls the travel actuators 5 in accordance with the target travel path 3 generated by the path generation section 14. Thereby, the host vehicle 1 can be caused to travel along the appropriate target travel path 3 even at a low vehicle speed.

[0064] In the above-described embodiment, an example in which the vehicle speed V is detected by the vehicle speed sensor 6 such as a wheel speed sensor is described, but the speed information acquisition section that acquires speed information of the host vehicle is not limited thereto. For example, the vehicle position can be determined from a positioning signal from a positioning satellite, and the vehicle speed can be calculated from a temporal change in the vehicle position.

[0065] In the above-described embodiment, an example in which the device 100 is provided with the travel control section 15 is described, but the path generation device is not limited thereto. For example, a display control section that controls a display section such as a head-up display to superimpose and display the target travel path 3 generated by the path generation section 14 on a road ahead of the vehicle can be provided.

[0066] In the above-described embodiments, an example in which the inter-vehicle distance from the host vehicle 1 to the preceding vehicle 4a is detected using the distance sensor 9 such as a millimeter wave radar or a laser radar is described, but the inter-vehicle distance from the host vehicle 1 to the preceding vehicle 4a can also be detected from image data of the front of the vehicle taken by the camera 8. In this case, the external sensor 7 can also be constituted only by the camera 8.

[0067] One or more of the above-described embodiments and modified examples can be arbitrarily combined, and each modified example can be combined with each other.

[0068] With the present application, an appropriate target travel path can be generated even at a low vehicle speed.

[0069] The present application has been described above in connection with preferred embodiments, but it will be understood by those skilled in the art that various modifications and changes can be made without departing from the scope of the disclosure as set forth in the following claims.

Claims

1. A route generating apparatus (100), characterized by, Possessing: An external sensor (7) mounted on the host vehicle (1) that detects an external condition centered on a traveling direction of the host vehicle (1); A passing point setting section (13) that sets a target passing point on a travel lane at the time of travel of the host vehicle (1) in accordance with the external condition detected by the external sensor (7); A path generating section (14) that generates a target travel path from a current point to the target passing point set by the passing point setting section (13); And A speed information obtaining section that obtains speed information of the host vehicle (1), The passing point setting section (13) sets the target passing point so that an X-axis coordinate, which indicates a distance in the traveling direction from the current point to the target passing point, is equal to a product of the traveling speed of the host vehicle (1) and a predetermined time period when the traveling speed of the host vehicle (1) is equal to or greater than a predetermined value, and sets the target passing point so that the X-axis coordinate is equal to a predicted distance when the traveling speed of the host vehicle (1) is less than the predetermined value, in accordance with the speed information obtained by the speed information obtaining section.

2. The path generating device (100) according to claim 1, characterized by Further comprising a distance detecting section (9) that detects an inter-vehicle distance from the host vehicle (1) to a preceding vehicle that travels ahead of the host vehicle (1) on a travel lane on which the host vehicle (1) travels.

3. The path generating device (100) according to claim 1 or 2, characterized by Further comprising a curvature radius calculating section (12) that calculates a curvature radius of the travel lane on which the host vehicle (1) travels, The passing point setting section (13) further sets the target passing point in accordance with the curvature radius calculated by the curvature radius calculating section (12).

4. The path generating device (100) according to claim 1 or 2, characterized by Further comprising a travel control section (15) that controls a travel actuator (5) to perform driving assistance for a driver of the host vehicle (1) or to automatically drive the host vehicle (1), The travel control section (15) controls the travel actuator (5) in accordance with the target travel path generated by the path generating section (14).

5. The path generating device (100) according to claim 1 or 2, characterized in that The external sensor (7) includes a camera.

6. The path generating device (100) according to claim 2, characterized in that The distance detecting section (9) is any one of a camera, a millimeter wave radar, and a laser radar.

7. A path generation method of generating a target travel path of a host vehicle (1), characterized by, Including: Setting a target passing point on a travel lane at the time of travel of the host vehicle (1) in accordance with an external condition centered on a traveling direction of the host vehicle (1) detected by an external sensor (7) mounted on the host vehicle (1); Generating the target travel path from a current point to the target passing point; Obtaining speed information of the host vehicle (1), The setting of the target passing point includes: according to the speed information, when the traveling speed of the host vehicle (1) is equal to or greater than a predetermined value, setting the target passing point such that the X-axis coordinate, which represents the distance in the traveling direction from the current position to the target passing point, is equal to the product of the traveling speed of the host vehicle (1) and a predetermined time period; and when the traveling speed of the host vehicle (1) is less than the predetermined value, setting the target passing point such that the X-axis coordinate is equal to the predicted distance.

8. The path generation method according to claim 7, wherein The setting of the target passing point includes: detecting, by a distance detection unit (9), the inter-vehicle distance from the host vehicle (1) to a preceding vehicle traveling ahead of the host vehicle (1) on a travel lane on which the host vehicle (1) travels.

9. The path generation method according to claim 7, wherein Further comprising calculating the radius of curvature of the travel lane on which the host vehicle (1) travels, The setting of the target passing point further includes setting the target passing point in accordance with the radius of curvature.

10. The path generation method according to claim 7, wherein Further comprising controlling a travel actuator (5) to perform driving assistance for a driver of the host vehicle (1) or to automatically drive the host vehicle (1), The control includes controlling the travel actuator (5) in accordance with the target travel path.

11. The path generation method according to claim 7, wherein The external sensor (7) includes a camera.

12. The path generation method according to claim 8, wherein The distance detection unit (9) is any one of a camera, a millimeter wave radar, and a laser radar.

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