Route generation method and vehicle

Abstract

To enable the generation of a travel route where a shock or vibration coming from a road surface to a vehicle can be effectively reduced in a case where there is irregularity on a road surface ahead of the vehicle.SOLUTION: A route generation method generates a travel route where shock or vibration coming from a road surface to a vehicle can be reduced. The method includes: recognizing height distribution of a road surface ahead of the vehicle; calculating, from the height distribution, a grand total of absolute values of extreme values of change rate of road heights along a vehicle proceeding direction per road position in a vehicle width direction; and generating the travel route so that wheels pass road positions that make the grand total a minimum.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present disclosure relates to a route generation method suitable for rough roads and a vehicle. [Background technology]

[0002] Patent Document 1 discloses a vehicle control device that, upon detecting a depression on the road on which the vehicle is traveling, if the vehicle cannot be driven without both wheels coming into contact with the depression, causes the vehicle to travel in a manner that is biased toward a more gradual rate of change in the height of the depression in the vehicle width direction. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2020-147139 Summary of the Invention [Problem to be solved by the invention]

[0004] The slope of the road surface relative to the vehicle's travel direction has a large effect on the vibrations that a moving vehicle experiences from the road surface. For this reason, the method described in Patent Document 1, in which the vehicle is driven so that the rate of change in height of the depression relative to the vehicle's width is more gradual, does not necessarily generate a driving route that can sufficiently reduce the vibrations that the vehicle experiences from the road surface when passing over a depression.

[0005] The present disclosure has been made in consideration of the above-mentioned problems, and its purpose is to make it possible to generate a driving route that can effectively reduce the shaking that the vehicle experiences from the road surface when the road surface ahead of the vehicle is uneven. [Means for solving the problem]

[0006] A route generation method according to the present disclosure generates a driving route that reduces vibrations that a vehicle receives from a road surface. The route generation method includes: recognizing a height distribution of a road surface ahead of the vehicle; calculating, for each road surface position in the vehicle width direction, from the height distribution, a sum of absolute values of extreme values of a rate of change of road surface height along the vehicle traveling direction; and generating a driving route such that the wheels pass through the road surface position where the sum is minimum.

[0007] The generation of the travel route may be performed so that the sum of the total sums at road surface positions passed by the left and right wheels included in the wheels is minimized.

[0008] A route generation device according to the present disclosure generates a driving route that reduces vibrations that a vehicle receives from a road surface, and includes a recognition sensor and one or more processors. The recognition sensor recognizes the situation around the vehicle. The one or more processors execute the following processes: a process of recognizing the height distribution of the road surface ahead of the vehicle using the recognition sensor; a process of calculating, for each road surface position in the vehicle width direction, from the height distribution, the sum of the absolute values of the extreme values of the rate of change of road surface height along the vehicle traveling direction; and a generation process of generating a driving route so that the wheels pass through the road surface position where the sum is minimum.

[0009] In the generation process, the one or more processors may execute the generation of the travel route so that the sum of the total sums at road surface positions passed by the left and right wheels included in the wheels is minimized. [Effects of the Invention]

[0010] The vibrations that a vehicle receives from the road surface when passing over an uneven portion of the road surface are proportional to the sum of the absolute values of the extreme values of the rate of change of the road surface height along the vehicle's traveling direction. According to the present disclosure, a driving route is generated so that the wheels pass through the road surface position where this sum is minimum. Therefore, when the road surface ahead of the vehicle is uneven, it is possible to generate a driving route that can effectively reduce the vibrations that the vehicle receives from the road surface. [Brief explanation of the drawings]

[0011] [Figure 1]1 is a block diagram showing an example of the configuration of a vehicle control system mounted on a vehicle according to an embodiment; [Figure 2] FIG. 1 is a diagram illustrating a vehicle traveling on a rough road. [Figure 3] FIG. 2 is a diagram for explaining a height distribution h(X, Y) used in the embodiment. [Figure 4] 1A shows a cross-section of the road surface (including depression Z) ahead of the vehicle along the vehicle travel direction D1 at a certain road surface position X, and FIG. 1B shows the rate of change dh / dy of road surface height h along the vehicle travel direction D1. [Figure 5] FIG. 10 is a diagram for explaining an example of a specific method for acquiring a shaking distribution. [Figure 6] 4 is a flowchart showing the process of the route generation method according to the embodiment and the process of steering control for realizing the generated travel route. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. In the embodiments described below, when the number, quantity, amount, range, etc. of each element is mentioned, the technical idea of the present disclosure is not limited to the mentioned number unless otherwise specified or clearly specified in principle.

[0013] 1. Example of vehicle configuration 1 is a block diagram showing an example of the configuration of a vehicle control system 10 mounted on a vehicle 1 according to an embodiment. The vehicle control system 10 is mounted on the vehicle 1 and controls the automatic driving of the vehicle 1. The vehicle control system 10 includes a vehicle state sensor 20, a recognition sensor 30, a position sensor 40, a communication device 50, a driving device 60, and an electronic control unit (ECU) 70.

[0014] The vehicle state sensor 20 detects the state of the vehicle 1. The vehicle state sensor 20 includes, for example, a wheel speed sensor, an acceleration sensor, a yaw rate sensor, a steering angle sensor, and the like.

[0015] The recognition sensor (external sensor) 30 recognizes (detects) the situation around the vehicle 1. Examples of the recognition sensor 30 include a camera, a LIDAR (Laser Imaging Detection and Ranging), and a radar.

[0016] The position sensor 40 detects the position and orientation of the vehicle 1. For example, the position sensor 40 includes a GNSS (Global Navigation Satellite System) receiver.

[0017] The communication device 50 communicates with the outside of the vehicle 1 .

[0018] The traveling device 60 includes a steering device 61, a drive device 62, and a braking device 63. The steering device 61 steers the wheels 2 (see FIG. 2). For example, the steering device 61 includes an electric power steering (EPS) device. The drive device 62 is a power source that generates driving force. Examples of the drive device 62 include an engine, an electric motor, and an in-wheel motor. The braking device 63 generates braking force.

[0019] The ECU 70 is a computer that controls the vehicle 1. The ECU 70 includes one or more processors 71 (hereinafter simply referred to as processors 71) and one or more storage devices 72 (hereinafter simply referred to as storage devices 72). The processor 71 executes various processes. For example, the processor 71 includes a CPU (Central Processing Unit). The storage device 72 stores various information required for processing by the processor 71. Examples of the storage device 72 include a volatile memory, a non-volatile memory, an HDD (Hard Disk Drive), an SSD (Solid State Drive), etc. There may be multiple ECUs 70.

[0020] The vehicle control program 80 is a computer program executed by the processor 71. When the processor 71 executes the vehicle control program 80, vehicle driving control (including automatic driving control) is realized by the ECU 70. The vehicle control program 80 is stored in the storage device 72. Alternatively, the vehicle control program 80 may be recorded on a computer-readable recording medium.

[0021] The driving environment information 90 is information indicating the driving environment of the vehicle 1 and is stored in the storage device 72. The driving environment information 90 includes map information, vehicle state information, surrounding situation information, and position information. More specifically, the vehicle state information is information indicating the state of the vehicle 1, such as the wheel speed (vehicle speed), yaw rate, lateral acceleration, and steering angle, and is acquired using the vehicle state sensor 20. The surrounding situation information is information indicating the situation around the vehicle 1 and is acquired using the recognition sensor 30. The surrounding situation information includes, for example, image information captured by a camera. The position information is information indicating the position and orientation (vehicle traveling direction) of the vehicle 1 and is acquired from the measurement results by the position sensor 40.

[0022] 2. Basic configuration example of vehicle driving control First, the ECU 70 executes "vehicle driving control" to control the driving of the vehicle 1. The vehicle driving control includes steering control, acceleration control, and deceleration control. The ECU 70 executes vehicle driving control by controlling the driving device 60. Specifically, the ECU 70 executes steering control by controlling the steering device 61. The ECU 70 also executes acceleration control by controlling the drive device 62. The ECU 70 also executes deceleration control by controlling the braking device 63.

[0023] The vehicle driving control includes automatic driving control that controls automatic driving of the vehicle 1. The ECU 70 performs automatic driving control based on driving environment information 90. The automatic driving here is assumed to be one that does not necessarily require the driver to concentrate 100% on driving (for example, so-called level 3 or higher automatic driving).

[0024] When performing the automatic driving control, the ECU 70 performs a recognition process to recognize the situation around the vehicle 1 using the recognition sensor 30. Then, the ECU 70 executes the automatic driving control based on the result of the recognition process.

[0025] More specifically, the ECU 70 generates a driving plan for the vehicle 1 based on the driving environment information 90. Examples of the driving plan include maintaining the current driving lane, changing lanes, and avoiding obstacles. The ECU 70 generates a target trajectory required for the vehicle 1 to travel in accordance with the driving plan based on the driving environment information 90. Generating a driving plan includes generating a target route and generating a speed plan. In other words, the target trajectory includes a target position and a target speed of the vehicle 1 within the road on which the vehicle 1 is traveling.

[0026] As an example, the target route is basically set to the center position of the lane L (see FIG. 2) of the vehicle 1. The lane L is an area sandwiched between left and right white lines WL, and the relative positions of the white lines WL are obtained from the surrounding situation information. The target route may also be set to avoid obstacles. The relative positions of the obstacles are obtained from the surrounding situation information. The ECU 70 performs vehicle driving control so that the vehicle 1 follows the target trajectory.

[0027] 3. Route generation method for rough roads FIG. 2 is a diagram showing a vehicle 1 traveling on a rough road. The vehicle 1 may travel on a rough road such as an uneven road. FIG. 2 shows, as an example, a scene in which a depression Z exists ahead of the vehicle on a travel lane L. The width D2 of this depression Z in the vehicle width direction is greater than the distance between the inner sides of the left and right wheels 2 of the vehicle 1.

[0028] Uneven portions such as a depression Z present in front of the vehicle 1 are recognized by a recognition sensor 30. More specifically, examples of the recognition sensor 30 for recognizing uneven portions include a camera that captures images in front of the vehicle, a radar such as a millimeter wave radar, etc. The camera used to recognize uneven portions may be, for example, a camera mounted to recognize targets in front of the vehicle, or a camera mounted to estimate the vehicle 1's own position.

[0029] When the ECU 70 recognizes an uneven portion on the road surface ahead, if the vehicle 1 can cross over the uneven portion within the driving lane L, the ECU 70 generates a driving path (target path) so that the vehicle 1 can cross over the uneven portion. On the other hand, if an uneven portion that the vehicle 1 cannot cross over, such as the depression Z shown in Fig. 2, exists on the driving lane L, it is impossible to keep the vehicle 1 within the driving lane L without the left and right wheels 2L and 2R running over the uneven portion.

[0030] Therefore, in this embodiment, in order to effectively reduce the shaking that the vehicle 1 receives from the road surface even when the wheels 2 need to pass over uneven areas, a driving route is generated according to the following route generation method.

[0031] The route generation method of this embodiment includes: recognizing a height distribution of a road surface ahead of the vehicle; calculating from the height distribution a sum of absolute values of extreme values of the rate of change of road surface height along the vehicle traveling direction D1 for each road surface position in the vehicle width direction D2; and generating a travel route such that the wheels 2 pass through a road surface position where the sum is minimum. Then, as an example, the travel route is generated so that the sum of the sums at the road surface positions where the left and right wheels 2L and 2R of the vehicle 1 pass is minimum.

[0032] 3 is a diagram for explaining the height distribution h(X, Y) used in the embodiment. The up-down direction on the paper surface of FIG. 3 is parallel to the vehicle traveling direction D1, and the left-right direction on the paper surface is parallel to the vehicle width direction D2. As an example, the position X in the vehicle width direction (hereinafter also simply referred to as "width direction position X") is zero at the position of the white line WL on the left side of the vehicle 1, and the position Y in the vehicle traveling direction D1 (hereinafter also simply referred to as "traveling direction position Y") is zero at the front end of the vehicle 1.

[0033] 3 shows the height distribution h(X, Y) of the depression Z shown in FIG. 2 as an example of the height distribution of an uneven portion of the road surface ahead of the vehicle. Since the depression Z is an example of an uneven portion with a concave shape, the height distribution h(X, Y) corresponds to the depth distribution h(X, Y). In the example of the depression Z, as shown in FIG. 3, the depression Z becomes deeper toward the inside of the depression Z. The height distribution h(X, Y) is recognized by the recognition sensor 30.

[0034] Fig. 4(A) shows a cross section (cross section along line AA) of the road surface (including depression Z) ahead of the vehicle along the vehicle travel direction D1 at a certain road surface position X. The vertical axis of Fig. 4(A) is road surface height (road surface depth) h, and the horizontal axis is travel direction position Y. Fig. 4(B) shows the rate of change dh / dy of the road surface height h along the vehicle travel direction D1.

[0035] When the vehicle 1 (wheel 2) passes through a portion of the depression Z where the height (depth) along the vehicle travel direction D1 is gentle, the vehicle 1 experiences less vibration from the depression Z when passing over the depression Z. The gentleness of the gradient is determined by the magnitude of the extreme value of the rate of change dh / dy of the road surface height h along the vehicle travel direction D1 (in other words, the amount of change in the gradient of the road surface height h). The vibration that the vehicle 1 experiences from the depression Z when traversing the depression Z at a road surface position X in the vehicle width direction D2 is proportional to the sum v(X) of the absolute values of the extreme values, as shown in FIG. 4(B). In other words, the larger the sum v(X), the greater the vibration. In other words, if the lateral position of the vehicle 1 can be determined so that the left and right wheels 2L and 2R pass through a point where the sum v(X) is minimum, it is believed that the vibration that the vehicle 1 experiences from the depression Z when the wheels 2 need to pass over the depression Z can be minimized.

[0036] Therefore, in this embodiment, the road surface position X k For each time, the sum of the absolute values of the extreme values of the rate of change dh / dy of the road surface height h is v(X k ) is calculated from the height distribution h(X, Y). k The sum v(X k ) is also called the wobble distribution for the depression Z.

[0037] FIG. 5 is a diagram for explaining an example of a specific method for obtaining the shaking distribution. In the example shown in FIG. 5, each sum v(X k ) the road surface position X in the vehicle width direction D2 associated with k are specified at intervals equal to the wheel width w. In this example, the sway distribution is acquired within the lane width W of the driving lane L. Specifically, the road surface position X k When the lane width W is divided by the wheel width w, the quotient is n, and the road surface positions X1 to X n It should be noted that when the lane width W is divided by the wheel width w, a remainder may occur, but this remainder can be ignored, for example.

[0038] In the vehicle travel direction D1, as shown in FIG. 5(A), the road surface of a predetermined length Y0 in front of the vehicle including the depression Z has a total of v(X k ) is calculated. This length Y0 has a predetermined value. In an example where a camera is used as the recognition sensor 30, the length Y0 is determined according to, for example, the angle of view (vertical angle of view) of the camera.

[0039] The sum v(X k ) is calculated by the process shown in FIG. 6, which will be described later. k ) for k, a natural number between 1 and n, the distribution of the sum v(X) (vibration distribution) as shown in FIG. 5(B) is obtained. As shown in FIG. 5(A), the sum v(X k ) is, for example, the road surface position X k-1 From road surface position X k is associated with the section up to

[0040] Fig. 5(B) shows the vibration distribution obtained for the road surface ahead including the depression Z shown in Fig. 5(A). As can be seen from Fig. 5(A) and Fig. 5(B), the vibration distribution indicates that large vibrations occur in areas where the depression Z is deep.

[0041] In this embodiment, the travel path of the vehicle 1 is generated based on the obtained swing distribution as shown in FIG. 5(B). Specifically, the sum v(X k ) and v(X k +d) is set as the target lateral position. An example of such a target lateral position is shown in FIG. 5(B). The lateral position of the vehicle 1 corresponds to the position of the vehicle 1 in the vehicle width direction D2 (for example, the center position of the vehicle 1 in the vehicle width direction D2) relative to a reference point (for example, road surface position X0 corresponding to the position of the white line WL on the left side of the driving lane L).

[0042] 6 is a flowchart showing the process of the route generation method according to the embodiment and the process of steering control for realizing the generated travel route. The process of this flowchart is repeatedly executed while the vehicle 1 is traveling. As an example, the ECU 70 is assumed to constantly recognize (generate) the height distribution h(X, Y) of the road surface ahead of the vehicle as shown in FIG. 3 based on surrounding situation information obtained from the recognition sensor 30. Alternatively, the recognition of the height distribution h(X, Y) may be executed only when, for example, an uneven portion such as a depression is detected on the road surface ahead of the vehicle.

[0043] In step S100 of FIG. 6, the ECU 70 calculates the road surface position X k The number k used to identify the vehicle 1 is set to zero. The road surface position X0 is assumed to be zero (for example, the position of the white line WL on the left side of the vehicle 1 shown in FIG. 2). The sum v(X0) is also assumed to be zero.

[0044] Next, in step S102, the ECU 70 calculates the final sum V(X k ) starts a loop process (steps S104 to S110).

[0045] First, in step S104, the ECU 70 counts up the number k to k+1. Next, in step S106, the ECU 70 calculates the road surface position X k―1 and the wheel width w, the road surface position X kIdentify as:

[0046] Next, in step S108, the ECU 70 calculates the sum v(X k ) and the sum v(X k +d) and the sum V(X k ) is calculated. Here, the sum v(X k ) is used as an index showing the magnitude of the vibration that the left wheel 2L receives from the road surface, and the sum v(X k +d) is used as an index showing the magnitude of vibration that the right wheel 2R receives from the road surface. k ) and v(X k +d) is calculated, for example, using the following formula (1):

number

[0047] The function h(Y|X) on the right side of equation (1) corresponds to the height distribution h(X, Y) shown in Figure 3. For example, if X in the function h(Y|X) is the road surface position X k When is substituted, the function h(Y|X k ) is the road surface position X k represents the height distribution along the vehicle travel direction D1 at the point. Then, in order to obtain the sum v(X) of the absolute values of the extreme values of the rate of change of the road surface height h along the vehicle travel direction D1, the right side of equation (1) differentiates the function h(Y|X) twice, expresses it as an absolute value, and then integrates it with respect to the position Y in the travel direction. The "0.5" included in the right side is a coefficient for calculating the sum. The integration interval corresponds to the length Y0 (see FIG. 5(A)).

[0048] According to the above formula (1), the road surface position X is added to the right side of the formula k By substituting, the sum v(X k ) can be calculated, and similarly, the road surface position X can be calculated by adding X to the right side. k By substituting +d, the sum v(X k +d) can be calculated. Then, the calculated sum v(X k ) and v(X k +d) to get the final sum V(Xk ) can be calculated.

[0049] Next, in step S110, the ECU 70 determines whether the number k is equal to a natural number 1. This natural number 1 is expressed by the following equation (2) using the lane width W, the width d between the left and right wheels, and the wheel width w, all of which are shown in FIG.

number

[0050] More specifically, the lane width W used to determine the natural number l can be obtained, for example, based on position information of the left and right white lines WL of the driving lane L detected by the recognition sensor 30. The left and right wheel-to-wheel distance d and wheel width w are known. The natural number l corresponds to the number of times that the positions of the left and right wheels 2L and 2R can be moved in the vehicle width direction D2 within the lane width W by the unit of wheel width w.

[0051] If the result of the determination in step S110 is No (i.e., the number k has not reached the natural number 1), the processing from step S104 onwards is repeatedly executed. On the other hand, if the result of the determination is Yes (i.e., the number k has reached the natural number 1), the processing proceeds to step S112, where the "final sum V(X k The loop process for calculating "(x,y)" is then terminated.

[0052] Next, in step S114, the ECU 70 calculates the sum v(X k ) and the sum v(X k +d) and the sum V(X k ) is the road surface position X where k A target lateral position of the vehicle 1 is determined so that the left wheel 2L passes through the intersection. In other words, a target route of the vehicle 1 is determined.

[0053] Next, in step S116, the ECU 70 executes steering control based on the target lateral position determined in step S114. Specifically, the ECU 70 calculates a steering amount corresponding to the target lateral position, and reflects the calculated steering amount in the steering control by the steering device 61.

[0054] 3.Effects As described above, according to the route generation method of this embodiment, a travel route is generated so that the wheels 2 pass through the road surface position where the sum of the absolute values of the extreme values of the rate of change dh / dy of the road surface height h along the vehicle traveling direction D1 is minimum. More specifically, the travel route is generated by determining the road surface position X through which the left and right wheels 2L and 2R of the vehicle 1 pass, respectively. k and X k +d in the sum v(X k ) and (X k +d) sum V(X k ) is minimized. The vibration that the vehicle 1 receives from the road surface when passing over an uneven portion of the road surface is proportional to the sum v(X) of the absolute values of the rate of change of the road surface height h. Therefore, according to the route generation method of this embodiment, when the road surface ahead of the vehicle is uneven, it is possible to generate a driving route that can effectively reduce the vibration that the vehicle 1 receives from the road surface.

[0055] 4. Other embodiments In the above-described embodiment, the driving route (target lateral position) for reducing sway of the vehicle 1 is determined so that the vehicle 1 can stay within the driving lane L. Therefore, the vehicle 1 can effectively reduce sway when traveling on a rough road while maintaining the driving lane L. However, the "route generation method" according to the present disclosure does not necessarily have to determine the driving route so that the vehicle 1 can stay within the driving lane L. That is, for example, the driving route generated by the route generation method may be generated so that sway received from uneven portions as the vehicle 1 crosses lanes is reduced. More specifically, the width of the sway distribution in the vehicle width direction D2 may be determined arbitrarily within the range of the forward road surface recognizable by the recognition sensor 30. In addition, the road for which a driving route is generated by the route generation method is not limited to a paved road, and may be, for example, an unpaved road.

[0056] In the above-described embodiment, each sum v(X) constituting the distribution of the sum v(X) (vibration distribution) k ) the road surface position X in the vehicle width direction D2 associated with k are specified at intervals equal to the wheel width w. However, the road surface position Xk The spacing between the wheels does not necessarily have to be equal to the wheel width w, that is, it may be narrower or wider than the wheel width w.

[0057] In the above-described embodiment, the travel route is defined as a road surface position X k and X k +d in the sum v(X k ) and (X k +d)'s "SuV(X k However, the "route Generate The driving route generated by the "method" does not necessarily have to take into account the vibrations that both the left and right wheels 2L and 2R receive from the road surface. That is, for example, if one of the left and right wheels can avoid unevenness on the road surface but the other wheel cannot, the driving route (target lateral position) may be generated taking into account only the other wheel. More specifically, the driving route may be generated so that the other wheel passes through the road surface position where the sum v(X) is minimum. [Explanation of symbols]

[0058] 1 vehicle 2, 2L, 2R wheels 10 Vehicle Control System 20 Vehicle condition sensor 30 Recognition Sensor 40 Position Sensor 61 Steering gear 70 Electronic Control Unit (ECU) 71 processors 72 Storage device

Claims

1. A route generation method for generating a driving route that reduces vibrations that a vehicle receives from a road surface, comprising: Recognizing the height distribution of the road surface ahead of the vehicle; calculating, from the height distribution, a sum of absolute values of extreme values of the rate of change of road surface height along the vehicle traveling direction for each road surface position in the vehicle width direction; generating a travel route such that the wheels pass through a road surface position where the sum is minimum; Contains Route generation method.

2. 2. The route generation method according to claim 1, The generation of the travel route is executed so that the sum of the total sums at road surface positions where the left and right wheels included in the vehicle pass is minimized. Contains Route generation method.

3. A route generation device that generates a driving route that reduces vibrations that a vehicle receives from a road surface, a recognition sensor that recognizes the surrounding situation of the vehicle; one or more processors; Equipped with the one or more processors: a process of recognizing a height distribution of a road surface ahead of a vehicle using the recognition sensor; calculating, from the height distribution, a sum of absolute values of extreme values of the rate of change of road surface height along the vehicle traveling direction for each road surface position in the vehicle width direction; a generation process for generating a travel path such that the wheels pass through a road surface position where the sum is minimum; Run Route generation device.

4. The route generation device according to claim 3, The wheels include left and right wheels of the vehicle, In the generation process, the one or more processors generate the travel route so that the sum of the total sums at road surface positions where left and right wheels included in the vehicle pass is minimized. Route generation device.

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