Vehicle control device, vehicle control method, and program

Abstract

A vehicle control device that performs automatic driving of a vehicle based on a detection result of a LiDAR mounted on the vehicle, the vehicle control device calculating a road surface equivalent height that corresponds to a height of a road surface on which the vehicle is traveling, based on reflection points detected by the LiDAR, calculating a number of reflection points that are within a prescribed range from the road surface equivalent height, calculating a region in which a density of the reflection points that are within the prescribed range from the road surface equivalent height is less than a prescribed value, calculating a shortest distance from the vehicle to the region in which the density of the reflection points is less than the prescribed value as a detection limit distance, and determining an upper limit vehicle speed of the vehicle based on the detection limit distance.

Description

Technical Field

[0001] This invention relates to a vehicle control device, a vehicle control method, and a program. Background Technology

[0002] Japanese Patent Application Publication No. 2022-146522 discloses a vehicle control device for performing autonomous driving. In the technology disclosed in Japanese Patent Application Publication No. 2022-146522, it is determined based on dynamic map data whether the detection capability of surrounding monitoring sensors falls below a predetermined requirement level within a predicted timeframe. Summary of the Invention

[0003] In the technology described in Japanese Patent Application Publication No. 2022-146522, map data is used to perform autonomous driving of a vehicle. However, in places such as mines where the terrain changes frequently, map data cannot be used to perform autonomous driving of a vehicle. Furthermore, in places such as mines where the external environment of the vehicle is constantly changing, there are no terrain features (landmarks) that are usually used to monitor the status of the surrounding monitoring sensors mounted on the vehicle, so it is impossible to use terrain features to monitor the status of the surrounding monitoring sensors.

[0004] Typically, when a vehicle is in an environment with external interference that degrades the detection performance of surrounding monitoring sensors, such as rain or fog, it is determined to be outside the Operating Design Domain (ODD). Driving authority is then delegated from the system to the human (driver), and the system-based vehicle operation is halted. In autonomous driving systems designed for unmanned operation, if the vehicle is determined to be in adverse conditions and unmanned operation based on the autonomous driving system frequently stops, the operational rate of the unmanned service will decrease.

[0005] For example, there is a desire for a technology that can suppress the decline in the operating rate of autonomous vehicles in environments such as mines.

[0006] In view of the above, the object of the present invention is to provide a vehicle control device, vehicle control method and program that can suppress the decline in the operating rate of autonomous driving even in environments such as mines.

[0007] One aspect of the present invention is a vehicle control device that performs autonomous driving of the vehicle based on detection results from a LiDAR system mounted on the vehicle. The vehicle control device comprises:

[0008] The road surface equivalent height calculation unit calculates the equivalent height of the road surface when the vehicle is traveling, based on the reflection points detected by the LiDAR.

[0009] The reflection point count calculation unit calculates the number of reflection points located at a height within a specified range from the equivalent height of the road surface, i.e., the number of reflection points at the equivalent height of the road surface.

[0010] The low-density reflection point zoning calculation unit calculates the zoning of the road surface where the density of reflection points at a certain height is less than a specified value, i.e., the low-density reflection point zoning.

[0011] The road surface detection limit distance calculation unit calculates the shortest distance between the low-density area of ​​the reflection point on the target travel track of the vehicle and the vehicle as the detection limit distance; and

[0012] The upper limit speed determination unit determines the upper limit speed of the vehicle based on the detection limit distance.

[0013] In the vehicle control device of the present invention, the reflection point number calculation unit can calculate the number of reflection points located at a height within a predetermined range from the equivalent height of the road surface, assuming that the road surface where the vehicle is traveling exists, i.e., the theoretical value of the number of reflection points.

[0014] The low-density zoning calculation unit for reflection points can determine that the density of reflection points at a given height of the road surface is less than the predetermined value if the ratio of the number of reflection points at a given height to the theoretical value of the number of reflection points is less than a predetermined ratio.

[0015] In the vehicle control device of the present invention, the low-density reflection point zoning calculation unit can determine whether the ratio of the number of reflection points at a comparable height of the road surface to the theoretical value of the number of reflection points is less than a predetermined ratio for each of a plurality of grid-like zoning defined in the planar coordinate system under the view of the vehicle.

[0016] One aspect of the present invention is a vehicle control method in which a vehicle control device performs autonomous driving of the vehicle based on the detection results of a LiDAR system mounted on the vehicle.

[0017] The vehicle control method includes:

[0018] The road surface equivalent height calculation step involves the vehicle control device calculating the equivalent height of the road surface while the vehicle is traveling, i.e., the road surface equivalent height, based on the reflection points detected by the LiDAR.

[0019] The vehicle control device calculates the number of reflection points at a height within a specified range from the equivalent height of the road surface, i.e., the number of reflection points at the equivalent height of the road surface.

[0020] The low-density reflection point zoning calculation step involves the vehicle control device calculating the zoning where the density of reflection points at a certain height of the road surface is less than a specified value, i.e., the low-density reflection point zoning.

[0021] The road surface detection limit distance calculation step involves the vehicle control device calculating the shortest distance between the low-density area of ​​the reflection point on the target travel track of the vehicle and the vehicle as the detection limit distance; and

[0022] In the step of determining the upper limit speed, the vehicle control device determines the upper limit speed of the vehicle based on the detection limit distance.

[0023] One aspect of the present invention is a program for causing a processor that performs autonomous driving of a vehicle based on detection results from a LiDAR mounted on the vehicle to execute the following steps:

[0024] The equivalent height of the road surface is calculated based on the reflection points detected by the LiDAR to determine the equivalent height of the road surface during vehicle travel, i.e., the equivalent height of the road surface.

[0025] The step of calculating the number of reflection points is to calculate the number of reflection points located at a height within a specified range from the equivalent height of the road surface, i.e., the number of reflection points at the equivalent height of the road surface.

[0026] The calculation steps for low-density reflection point zoning are as follows: the zoning of the road surface with a density of reflection points at a certain height that is less than a specified value is the low-density reflection point zoning.

[0027] The road surface detection limit distance calculation step involves calculating the shortest distance between the low-density area of ​​the reflection point on the target travel track of the vehicle and the vehicle as the detection limit distance; and

[0028] The upper limit speed determination step determines the upper limit speed of the vehicle based on the detection limit distance.

[0029] According to the present invention, for example, the decline in the operating rate of autonomous driving can be suppressed even in environments such as mines. Attached Figure Description

[0030] Hereinafter, with reference to the accompanying drawings, the features, advantages, and technical and industrial significance of exemplary embodiments of the present invention will be described, in which the same reference numerals denote the same elements, and wherein:

[0031] Figure 1 This is a diagram showing an example of a vehicle 1 to which the vehicle control device 14 of the first embodiment is applied.

[0032] Figure 2 This is a diagram illustrating an example of the target travel trajectory of vehicle 1.

[0033] Figure 3 This is a flowchart illustrating an example of the processing performed by the processor 143 of the vehicle control device 14 of the first embodiment. Detailed Implementation

[0034] Hereinafter, with reference to the accompanying drawings, embodiments of the vehicle control device, vehicle control method, and program of the present invention will be described.

[0035] Implementation Method 1

[0036] Figure 1 This is a diagram showing an example of a vehicle 1 to which the vehicle control device 14 of the first embodiment is applied.

[0037] exist Figure 1 In the example shown, vehicle 1 includes a Light Detection and Ranging (LiDAR) device 11, a Human Machine Interface (HMI) 12, a location information acquisition device 13, a vehicle control device 14, a steering actuator 14A, a brake actuator 14B, and a drive actuator 14C.

[0038] The LiDAR 11 measures the distance between the reflection point of the laser emitted from the LiDAR 11 and the LiDAR 11, as well as the direction of the reflection point. That is, the LiDAR 11 detects the reflection point of the laser emitted from the LiDAR 11 and sends the detection results (sensor data indicating the distance between the reflection point and the LiDAR 11, the direction of the reflection point, etc.) to the vehicle control unit 14.

[0039] HMI12 is capable of accepting various operations from the user of vehicle 1 (e.g., inputting the target travel trajectory of vehicle 1 (reference)). Figure 2 The system performs functions such as operation of the vehicle 1 and sends signals indicating the user's operation to the vehicle control unit 14.

[0040] Figure 2 This is a diagram illustrating an example of the target travel trajectory of vehicle 1.

[0041] exist Figure 2 In the example shown, vehicle 1 is directed towards Figure 2 The track for traveling only a specified distance to the left (e.g., westward) is set as the target travel track for vehicle 1.

[0042] exist Figure 1 In the example shown, the location information acquisition device 13 acquires information indicating the driving position of vehicle 1 (e.g., latitude, longitude, orientation (i.e., the position and orientation of vehicle 1)) and sends the information indicating the driving position of vehicle 1 to the vehicle control device 14. The location information acquisition device 13 includes, for example, a Global Positioning System (GPS) sensor.

[0043] The vehicle control unit 14 performs automatic driving of the vehicle 1 based on the detection results of the LiDAR 11, information indicating the target travel trajectory of the vehicle 1, and the vehicle 1's travel position (latitude, longitude, orientation (position and direction of the vehicle 1), etc.). More specifically, the vehicle control unit 14 controls the steering actuator 14A, the brake actuator 14B, and the drive actuator 14C. For example, if the LiDAR 11 detects an obstacle on the target travel trajectory of the vehicle 1, the vehicle control unit 14 executes control to make the vehicle 1 avoid the obstacle. The obstacle recognition device 14 is composed of a microcomputer equipped with a communication interface (I / F) 141, a memory 142, and a processor 143.

[0044] The communication interface 141 has an interface circuit for connecting the vehicle control device 14 to the LiDAR 11, HMI 12 and location information acquisition device 13.

[0045] The memory 142 stores the programs and various data used in the processing executed by the processor 143.

[0046] The processor 143 functions as an acquisition unit 3A, a detection unit 3B, a zoning definition unit 3C, and a road surface height calculation unit 3D. The processor 143 also functions as a reflection point quantity calculation unit 3E, a reflection point low-density zoning calculation unit 3F, a road surface detection limit distance calculation unit 3G, an upper limit vehicle speed determination unit 3H, and a control unit 3I.

[0047] The acquisition unit 3A acquires the detection results of LiDAR 11 (sensor data indicating the distance between the reflection point and LiDAR 11, the direction of the reflection point, etc.). Furthermore, the acquisition unit 3A acquires signals transmitted from HMI 12 indicating the user's actions on vehicle 1 (e.g., signals indicating the target travel trajectory of vehicle 1, etc.). Additionally, the acquisition unit 3A acquires information indicating the travel position of vehicle 1 transmitted from position information acquisition device 13.

[0048] The inspection department 3B uses the LiDAR11 test results to inspect the road structure and obstacles on the road surface when the vehicle 1 is in motion.

[0049] The zoning definition section 3C is defined in a planar coordinate system as seen from above by vehicle 1 (i.e., Figure 2 Multiple grid-like zones are defined in the plane coordinate system shown. Figure 2 In the example shown, each zone is a square (i.e., the two orthogonal sides that make up the zone are of equal length), but in other examples, each zone can also be a rectangle (i.e., the two orthogonal sides that make up the zone can be of different lengths).

[0050] exist Figure 1 In the example shown, the road surface equivalent height calculation unit 3D calculates the equivalent height of the road surface for which vehicle 1 is traveling, based on the reflection points detected by LiDAR 11. Specifically, the road surface equivalent height calculation unit 3D calculates the average height of multiple reflection points (reflection points detected by LiDAR 11) included in each of the multiple zones defined by the zone definition unit 3C within a predetermined range in the height direction as the road surface equivalent height of that zone. That is, reflection points with abnormal heights are excluded when calculating the road surface equivalent height of the zone.

[0051] In other examples, the road surface equivalent height calculation unit 3D can also calculate the average height of the multiple reflection points included in each of the multiple zones defined by the zone definition unit 3C (i.e., the average height of reflection points including those with abnormal heights) as the road surface equivalent height of that zone.

[0052] exist Figure 1 In the example shown, the reflection point number calculation unit 3E calculates the number of reflection points located at a height within a specified range from the road surface equivalent height calculated by the road surface equivalent height calculation unit 3D, i.e., the number of road surface equivalent height reflection points. Furthermore, the reflection point number calculation unit 3E calculates the number of reflection points (virtual reflection points) located at a height within a specified range from the road surface equivalent height, assuming the vehicle 1 is traveling on the road surface at a road surface equivalent height position, i.e., the theoretical value of the number of reflection points.

[0053] exist Figure 2 In the example shown, in the "low-density reflection point zone" within the area where the LiDAR reflection point set is obtained, the road surface where vehicle 1 is traveling is not at a position equivalent to the road surface height. For example, there are terrain features that are raised or sunken above the road surface height, or obstacles are present. On the other hand, in zones within the area where the LiDAR reflection point set is obtained that are not "low-density reflection point zones," the road surface where vehicle 1 is traveling is at a position equivalent to the road surface height. That is, vehicle 1 can travel in these zones.

[0054] exist Figure 1 In the example shown, the reflection point number calculation unit 3E calculates the theoretical value of the reflection point number by using, for example, the angle (beam angle) of the laser irradiating from LiDAR 11 to each of the multiple zones, the distance between LiDAR 11 and each of the multiple zones, and the height of the virtual reflection point included in each of the multiple zones. That is, the reflection point number calculation unit 3E uses the equivalent height of the road surface to calculate the theoretical value of the reflection point number.

[0055] In other examples, the reflection point number calculation unit 3E can also calculate the theoretical value of the reflection point number by using parameters different from those described above.

[0056] exist Figure 1 In the example shown, the low-density reflection point zoning calculation unit 3F calculates a low-density reflection point zoning zone where the density of reflection points at the equivalent height of the road surface is less than a specified value. Specifically, the low-density reflection point zoning calculation unit 3F determines whether the ratio of the number of reflection points at the equivalent height of the road surface to the theoretical value of the number of reflection points in each of the multiple zoning zones defined by the zoning definition unit 3C is less than a specified ratio.

[0057] Sometimes the ratio of the number of reflection points at a given road surface height to the theoretical value of the number of reflection points is less than a specified ratio. In this case, the low-density reflection point zoning calculation unit 3F determines that the density of reflection points at a given road surface height in that zoning area is less than a specified value. Then, the low-density reflection point zoning calculation unit 3F calculates that zoning area as a low-density reflection point zoning area. Figure 2 (The administrative divisions are indicated by shaded lines in the text).

[0058] The ratio of the number of road surface reflection points at a certain height to the theoretical value of the number of reflection points is sometimes greater than a predetermined ratio. In this case, the low-density reflection point zoning calculation unit 3F determines that the density of road surface reflection points at a certain height in the zoning is greater than or equal to a predetermined value. Then, the low-density reflection point zoning calculation unit 3F calculates the zoning as a zoning that is not a low-density reflection point zoning (in... Figure 2 In the example shown, the zoning corresponds to the area in the region where the LiDAR reflectance point group was obtained without shaded lines.

[0059] The road surface detection limit distance calculation unit 3G calculates the target travel trajectory of vehicle 1 (reference). Figure 2 Low-density zoning of reflection points on (reference) Figure 2 The shortest distance between vehicle 1 and vehicle 2 is used as the detection limit distance (reference). Figure 2 ).

[0060] exist Figure 2 In the example shown, the road surface detection limit distance calculation unit 3G calculates the distances between the three low-density reflection point areas with the shortest distance to vehicle 1 from the 60 low-density reflection point areas on the target travel track of vehicle 1 as the detection limit distance.

[0061] exist Figure 1 In the example shown, the upper limit speed determination unit 3H determines the upper limit speed of vehicle 1 based on the detection limit distance calculated by the road surface detection limit distance calculation unit 3G. Specifically, the shorter the detection limit distance calculated by the upper limit speed determination unit 3H, the lower the speed is calculated as the upper limit speed of vehicle 1.

[0062] The control unit 3I performs speed control of vehicle 1 based on the upper limit speed determined by the upper limit speed determination unit 3H.

[0063] Therefore, in Figure 1 In the example shown, the vehicle control device 14 can perform controls such as safely stopping the vehicle 1 within the detection limit distance.

[0064] That is, in Figure 1 In the example shown, the autonomous driving of vehicle 1 based on vehicle control device 14 can be immediately stopped when there are bumps, depressions, obstacles or other obstacles on the target driving track of vehicle 1 that prevent vehicle 1 from driving, thereby causing a decrease in the operation rate of autonomous driving.

[0065] Figure 3 This is a flowchart illustrating an example of the processing performed by the processor 143 of the vehicle control device 14 of the first embodiment.

[0066] exist Figure 3 In the example shown, processing for each zone is performed in S10 to S18.

[0067] Specifically, in S10, processing for each zone begins.

[0068] In S11, the zoning definition unit 3C defines the zoning in the planar coordinate system viewed from above by vehicle 1.

[0069] In S12, the road surface equivalent height calculation unit 3D calculates the road surface equivalent height of the zone defined in S11 based on the reflection points detected by LiDAR11 (multiple reflection points included in the zone defined in S11).

[0070] In S13, the reflection point number calculation unit 3E calculates the number of reflection points, i.e., road surface equivalent height reflection points, that are located within a specified range of the road surface equivalent height (calculated in S12) of the zone defined in S11.

[0071] The reflection point number calculation unit 3E sometimes indicates that a vehicle 1 within the zone defined in S11 is traveling on the road surface at a position equivalent to the road surface height calculated in S12. In this case, in S14, the number of reflection points (virtual reflection points included in the zone defined in S11) located at a height within a specified range from this equivalent road surface height is calculated, which is the theoretical value of the reflection point number.

[0072] In S15, the low-density zoning calculation unit 3F determines whether the ratio of the number of road surface reflection points at the equivalent height of the zoning defined in S11 to the theoretical value of the number of reflection points is less than a predetermined ratio. If the ratio is less than the predetermined ratio, the process proceeds to step S16. If the ratio is greater than or equal to the predetermined ratio, the process proceeds to step S17.

[0073] In S16, the low-density zoning calculation unit 3F determines that the zoning defined in S11 is a low-density zoning of reflection points.

[0074] In S17, the low-density zoning calculation unit 3F determines that the zoning defined in S11 is not a low-density zoning of reflection points.

[0075] If the processing of S11 to S17 is completed for all zones of the grid-like multiple zones defined in the planar coordinate system under the view of vehicle 1, then in S18, the processing for each zone is completed.

[0076] In S19, the road surface detection limit distance calculation unit 3G calculates the shortest distance between the low-density area of ​​the reflection point on the target travel track of vehicle 1 and vehicle 1 as the detection limit distance.

[0077] In S20, the upper limit speed determination unit 3H determines the upper limit speed of vehicle 1 based on the detection limit distance calculated in S19.

[0078] In S21, the control unit 3I performs speed control of vehicle 1 based on the upper limit vehicle speed determined in S20.

[0079] As described above, in the vehicle 1 to which the vehicle control device 14 of the first embodiment is applied, the shortest distance between the low-density area of ​​the reflection point on the target travel track of the vehicle 1 and the vehicle 1 is calculated as the detection limit distance, and the speed control of the vehicle 1 is performed based on the upper limit speed of the vehicle 1 determined based on this detection limit distance. Therefore, even if there is an obstacle at a position greater than the detection limit distance from the vehicle 1, when the distance between the vehicle 1 and the obstacle is less than the detection limit distance, the vehicle control device 14 can appropriately avoid collisions between the vehicle 1 and the obstacle, and continue the autonomous driving of the vehicle 1. As a result, when the vehicle 1 to which the vehicle control device 14 of the first embodiment is applied is used for unmanned operation services, the unmanned operation service can continue without causing unmanned operation to stop as much as possible.

[0080] Implementation Method 2

[0081] The vehicle 1 using the vehicle control device 14 of the second embodiment is configured in the same way as the vehicle 1 using the vehicle control device 14 of the first embodiment, except for the points described later.

[0082] As mentioned above, in Figure 1 In the example shown, the road surface equivalent height calculation unit 3D calculates the average height of the multiple reflection points included in each of the multiple zones defined by the zone definition unit 3C as the road surface equivalent height of that zone.

[0083] On the other hand, in an example of a vehicle 1 to which the vehicle control device 14 of the second embodiment is applied, the road surface equivalent height calculation unit 3D calculates a value other than the average value of the height of the multiple reflection points included in each of the multiple zones defined by the zone definition unit 3C as the road surface equivalent height of that zone.

[0084] As described above, embodiments of the vehicle control device, vehicle control method, and program of the present invention will be described with reference to the accompanying drawings. However, the vehicle control device, vehicle control method, and program of the present invention are not limited to the above embodiments, and can be appropriately modified without departing from the spirit of the present invention. The structures of the various examples of the above embodiments can be appropriately combined. In the examples of the above embodiments, the processing performed in the vehicle control device 14 is described as software processing performed by executing a program. However, the processing performed in the vehicle control device 14 can also be hardware processing. Alternatively, the processing performed in the vehicle control device 14 can be a combination of software and hardware processing. Furthermore, the program stored in the memory 142 of the vehicle control device 14 (the program that implements the functions of the processor 143 of the vehicle control device 14) can be recorded in a computer-readable storage medium such as a semiconductor memory, magnetic recording medium, or optical recording medium and provided or distributed.

Claims

1. A vehicle control device that performs autonomous driving of the vehicle based on detection results from a LiDAR mounted on the vehicle, the vehicle control device being characterized by comprising: The road surface equivalent height calculation unit calculates the equivalent height of the road surface when the vehicle is traveling, based on the reflection points detected by the LiDAR. The reflection point count calculation unit calculates the number of reflection points located at a height within a specified range from the equivalent height of the road surface, i.e., the number of reflection points at the equivalent height of the road surface. The low-density reflection point zoning calculation unit calculates the zoning of the road surface where the density of reflection points at a certain height is less than a specified value, i.e., the low-density reflection point zoning. The road surface detection limit distance calculation unit calculates the shortest distance between the low-density area of ​​the reflection point on the target travel track of the vehicle and the vehicle as the detection limit distance; and The upper limit speed determination unit determines the upper limit speed of the vehicle based on the detection limit distance.

2. The vehicle control device according to claim 1, characterized in that, The reflection point number calculation unit calculates the theoretical value of the number of reflection points located within a specified range from the equivalent height of the road surface, assuming the road surface where the vehicle is traveling exists. If the low-density zoning calculation unit determines that the density of reflection points at a given height of the road surface is less than the specified value when the ratio of the number of reflection points at a given height to the theoretical value of the number of reflection points is less than a specified ratio.

3. The vehicle control device according to claim 2, characterized in that, The low-density zoning calculation unit determines, for each of the multiple grid-like zoning defined in the planar coordinate system under the view of the vehicle, whether the ratio of the number of reflection points at a certain height of the road surface to the theoretical value of the number of reflection points is less than the specified ratio.

4. A vehicle control method, wherein a vehicle control device performs autonomous driving of the vehicle based on detection results from a LiDAR mounted on the vehicle, the vehicle control method being characterized by comprising: The road surface equivalent height calculation step involves the vehicle control device calculating the equivalent height of the road surface while the vehicle is traveling, i.e., the road surface equivalent height, based on the reflection points detected by the LiDAR. The vehicle control device calculates the number of reflection points at a height within a specified range from the equivalent height of the road surface, i.e., the number of reflection points at the equivalent height of the road surface. The low-density reflection point zoning calculation step involves the vehicle control device calculating the zoning where the density of reflection points at a certain height of the road surface is less than a specified value, i.e., the low-density reflection point zoning. The road surface detection limit distance calculation step involves the vehicle control device calculating the shortest distance between the low-density area of ​​the reflection point on the target travel track of the vehicle and the vehicle as the detection limit distance; and In the step of determining the upper limit speed, the vehicle control device determines the upper limit speed of the vehicle based on the detection limit distance.

5. A program, characterized in that, The program is used to cause the processor that performs autonomous driving of the vehicle based on the detection results of the LiDAR mounted on the vehicle to perform the following steps: The equivalent height of the road surface is calculated based on the reflection points detected by the LiDAR to determine the equivalent height of the road surface during vehicle travel, i.e., the equivalent height of the road surface. The step of calculating the number of reflection points is to calculate the number of reflection points located at a height within a specified range from the equivalent height of the road surface, i.e., the number of reflection points at the equivalent height of the road surface. The calculation steps for low-density reflection point zoning are as follows: the zoning of the road surface with a density of reflection points at a certain height that is less than a specified value is the low-density reflection point zoning. The road surface detection limit distance calculation step involves calculating the shortest distance between the low-density area of ​​the reflection point on the target travel track of the vehicle and the vehicle as the detection limit distance; and The upper limit speed determination step determines the upper limit speed of the vehicle based on the detection limit distance.

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