Vehicle control device, vehicle control method, and program

Abstract

This helps to suppress the decline in the operating rate of automated driving systems, even in environments such as mines. [Solution] A vehicle control device 14 that performs automatic driving of vehicle 1 based on the detection results of a LiDAR 11 mounted on vehicle 1 calculates the road surface equivalent height, which is the height corresponding to the road surface on which vehicle 1 is traveling, based on the reflection points detected by the LiDAR 11, calculates the number of road surface equivalent height reflection points, which are reflection points located at a height within a predetermined range from the road surface equivalent height, calculates the low-density reflection point area, which is an area where the density of road surface equivalent height reflection points is less than a predetermined value, calculates the shortest distance between the low-density reflection point area on the target driving trajectory of vehicle 1 and vehicle 1 as the detection limit distance, and determines the upper limit speed of vehicle 1 based on the detection limit distance.

Description

Technical Field

[0001] The present disclosure relates to a vehicle control device, a vehicle control method, and a program.

Background Art

[0002] Patent Document 1 describes a vehicle control device that executes autonomous driving. In the technology described in Patent Document 1, it is determined based on dynamic map data whether the detection ability of the surrounding monitoring sensor falls below a predetermined required level within a prediction time.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the technology described in Patent Document 1, map data is used to execute autonomous driving of a vehicle. However, for example, in a mine where the terrain frequently changes, map data cannot be used to execute autonomous driving of the vehicle. Further, in a mine or the like where the external environment of the vehicle constantly changes, there is no landmark generally used for monitoring the state of the surrounding monitoring sensors mounted on the vehicle, so the state of the surrounding monitoring sensors cannot be monitored using landmarks. Generally, when a vehicle is in a disturbed environment such as rain or fog that causes a decrease in the detection performance of the surrounding monitoring sensors, it is determined that the vehicle is outside the ODD (Operational Design Domain), and the driving authority is delegated from the system to a person (driver), and the vehicle running by the system is stopped. When the autonomous driving system is applied to an unmanned operation service, if it is determined that the vehicle is in a bad environment and the unmanned operation by the autonomous driving system is frequently stopped, the operation rate of the unmanned operation service will decrease. For example, there is a need for technology that can suppress the decline in the operating rate of autonomous vehicles in environments such as mines.

[0005] In view of the above, the purpose of this disclosure is to provide a vehicle control device, a vehicle control method, and a program that can suppress a decrease in the operating rate of automated driving even in environments such as mines. [Means for solving the problem]

[0006] (1) One aspect of the present disclosure is a vehicle control device that performs automatic driving of a vehicle based on the detection results of a LiDAR mounted on the vehicle, comprising: a road surface equivalent height calculation unit that calculates a road surface equivalent height which is the height corresponding to the road surface on which the vehicle is traveling based on the reflection points detected by the LiDAR; a reflection point number calculation unit that calculates the number of road surface equivalent height reflection points which are reflection points located at a height within a predetermined range from the road surface equivalent height; a reflection point low density area calculation unit that calculates a reflection point low density area which is an area in which the density of the road surface equivalent height reflection points is less than a predetermined value; a road surface detection limit distance calculation unit that calculates the shortest distance between the reflection point low density area on the target driving trajectory of the vehicle and the vehicle as the detection limit distance; and an upper limit vehicle speed determination unit that determines the upper limit vehicle speed of the vehicle based on the detection limit distance.

[0007] (2) In the vehicle control device of (1), the reflection point calculation unit calculates a theoretical value of reflection points, which is the number of reflection points located at a height within the predetermined range from the road surface height, assuming that the road surface on which the vehicle is traveling is at a height equivalent to the road surface. The low-density reflection point area calculation unit may determine that the density of reflection points at road surface height is less than the predetermined value if the ratio of the number of reflection points at road surface height to the theoretical value of reflection points is less than the predetermined ratio.

[0008] (3)(2) In the vehicle control device, the low-density reflection point section calculation unit may determine whether the ratio of the number of reflection points at road surface equivalent height to the theoretical value of the number of reflection points for each of the grid-like sections defined in the planar coordinate system of the top view of the vehicle is less than the predetermined ratio.

[0009] (4) One aspect of the present disclosure is a vehicle control method in which a vehicle control device performs automatic driving of the vehicle based on the detection results of a LiDAR mounted on the vehicle, comprising: a road surface equivalent height calculation step in which the vehicle control device calculates a road surface equivalent height which is the height corresponding to the road surface on which the vehicle is traveling, based on the reflection points detected by the LiDAR; a reflection point number calculation step in which the vehicle control device calculates the number of road surface equivalent height reflection points which are reflection points located at a height within a predetermined range from the road surface equivalent height; a reflection point low density area calculation step in which the vehicle control device calculates a reflection point low density area which is an area in which the density of the road surface equivalent height reflection points is less than a predetermined value; a road surface detection limit distance calculation step in which the vehicle control device calculates the shortest distance between the reflection point low density area on the target driving trajectory of the vehicle and the vehicle as the detection limit distance; and an upper limit vehicle speed determination step in which the vehicle control device determines the upper limit vehicle speed of the vehicle based on the detection limit distance.

[0010] (5) One aspect of the present disclosure is a program for causing a processor that performs autonomous driving of a vehicle based on the detection results of a LiDAR mounted on the vehicle to perform the following steps: a road surface equivalent height calculation step for calculating a road surface equivalent height which is the height corresponding to the road surface on which the vehicle is traveling, based on the reflection points detected by the LiDAR; a reflection point number calculation step for calculating the number of road surface equivalent height reflection points which are reflection points located at a height within a predetermined range from the road surface equivalent height; a reflection point low density area calculation step for calculating a reflection point low density area which is an area where the density of the road surface equivalent height reflection points is less than a predetermined value; a road surface detection limit distance calculation step for calculating the shortest distance between the reflection point low density area on the target driving trajectory of the vehicle and the vehicle as the detection limit distance; and an upper limit speed determination step for determining the upper limit speed of the vehicle based on the detection limit distance. [Effects of the Invention]

[0011] According to this disclosure, for example, it is possible to suppress the decline in the operating rate of automated driving even in environments such as mines. [Brief explanation of the drawing]

[0012] [Figure 1] This figure shows an example of a vehicle 1 to which the vehicle control device 14 of the first embodiment is applied. [Figure 2] This diagram illustrates an example of the target trajectory of vehicle 1. [Figure 3] This is a flowchart illustrating an example of processing performed by the processor 143 of the vehicle control device 14 of the first embodiment. [Modes for carrying out the invention]

[0013] Hereinafter, embodiments of the vehicle control device, vehicle control method, and program of this disclosure will be described with reference to the drawings.

[0014] <First Embodiment> Figure 1 shows an example of a vehicle 1 to which the vehicle control device 14 of the first embodiment is applied. In the example shown in Figure 1, vehicle 1 is equipped with a LiDAR (Light Detection and Ranging) 11, an HMI (Human Machine Interface) 12, a position information acquisition device 13, a vehicle control device 14, a steering actuator 14A, a braking actuator 14B, and a drive actuator 14C. The LiDAR 11 measures the distance between the reflection point that reflects the laser light emitted from the LiDAR 11 and the LiDAR 11, as well as the direction of the reflection point. In other words, the LiDAR 11 detects the reflection point that reflects the laser light emitted from the LiDAR 11 and transmits the detection result (sensor data indicating the distance between the reflection point and the LiDAR 11, the direction of the reflection point, etc.) to the vehicle control device 14. The HMI 12 has functions such as receiving various operations from the user of vehicle 1 (for example, operations to input the target travel trajectory of vehicle 1 (see Figure 2)), and transmits signals indicating the user's operations to the vehicle control device 14.

[0015] Figure 2 is a diagram illustrating an example of the target trajectory of vehicle 1. In the example shown in Figure 2, the target trajectory for vehicle 1 is set as a path in which vehicle 1 travels a predetermined distance to the left (for example, west) in Figure 2.

[0016] In the example shown in Figure 1, the location information acquisition device 13 acquires information indicating the vehicle's position (e.g., latitude, longitude, and direction (i.e., the position and orientation of the vehicle)) and transmits the information indicating the vehicle's position to the vehicle control device 14. The location information acquisition device 13 includes, for example, a GPS (Global Positioning System) sensor. The vehicle control device 14 performs automatic driving of the vehicle 1 based on information such as the detection results of the LiDAR 11, the target driving trajectory of the vehicle 1, and the driving position of the vehicle 1 (latitude, longitude, bearing (position and orientation of the vehicle 1), etc.). (Specifically, it controls the steering actuator 14A, the braking actuator 14B, and the drive actuator 14C.) For example, if an obstacle on the target driving trajectory of the vehicle 1 is detected by the LiDAR 11, the vehicle control device 14 performs control to cause the vehicle 1 to avoid the obstacle. The vehicle control device 14 is composed of a microcomputer equipped with a communication interface (I / F) 141, memory 142, and processor 143. The communication interface 141 has an interface circuit for connecting the vehicle control device 14 to the LiDAR 11, HMI 12, and position information acquisition device 13. Memory 142 stores programs and various data used in processing performed by processor 143. The processor 143 has the functions of an acquisition unit 3A, a detection unit 3B, a section definition unit 3C, a road surface equivalent height calculation unit 3D, a reflection point number calculation unit 3E, a reflection point low density section 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.

[0017] The acquisition unit 3A acquires the detection results of the LiDAR 11 (sensor data indicating the distance between the reflection point and the LiDAR 11, the direction of the reflection point, etc.). Further, the acquisition unit 3A acquires a signal indicating the operation of the user of the vehicle 1 transmitted from the HMI 12 (for example, a signal indicating the target travel trajectory of the vehicle 1, etc.). Furthermore, the acquisition unit 3A acquires information indicating the travel position of the vehicle 1 transmitted from the position information acquisition device 13. The detection unit 3B detects the structure of the road surface on which the vehicle 1 is traveling and obstacles on the road surface based on the detection results of the LiDAR 11. The section definition unit 3C defines a plurality of grid-shaped sections in the plane coordinate system of the top view of the vehicle 1 (that is, the plane coordinate system shown in FIG. 2). In the example shown in FIG. 2, each section is square (that is, the lengths of the two orthogonal sides constituting the section are equal), but in other examples, each section may be rectangular (that is, the lengths of the two orthogonal sides constituting the section may be different).

[0018] In the example shown in FIG. 1, the road surface equivalent height calculation unit 3D calculates the road surface equivalent height, which is the height corresponding to the road surface on which the vehicle 1 is traveling, based on the reflection points detected by the LiDAR 11. Specifically, the road surface equivalent height calculation unit 3D calculates the average value of the heights of a plurality of reflection points included within a predetermined range in the height direction among the plurality of reflection points (reflection points detected by the LiDAR 11) included in each of the plurality of sections defined by the section definition unit 3C as the road surface equivalent height of that section (that is, reflection points having abnormal heights are excluded and the road surface equivalent height of that section is calculated). In other examples, the road surface equivalent height calculation unit 3D may calculate the average value of the heights of the plurality of reflection points included in each of the plurality of sections defined by the section definition unit 3C (that is, the average value including reflection points having abnormal heights) as the road surface equivalent height of that section.

[0019] In the example shown in Figure 1, the reflection point calculation unit 3E calculates the number of road surface equivalent height reflection points, which are reflection points located at a predetermined height from the road surface equivalent height calculated by the road surface equivalent height calculation unit 3D. Furthermore, the reflection point calculation unit 3E calculates a theoretical value of reflection points, which is the number of reflection points (virtual reflection points) located at a predetermined height from the road surface equivalent height, assuming that the road surface on which the vehicle 1 is traveling is at the road surface equivalent height. In the example shown in Figure 2, in the "low-density reflection point area" within the region where LiDAR reflection point cloud data is obtained, the road surface on which vehicle 1 is traveling is not at the equivalent height of the road surface (for example, the terrain is higher or lower than the equivalent height of the road surface, or there are obstacles). On the other hand, in the areas within the region where LiDAR reflection point cloud data is obtained that are not the "low-density reflection point area," the road surface on which vehicle 1 is traveling is at the equivalent height of the road surface. In other words, vehicle 1 can travel through those areas. In the example shown in Figure 1, the reflection point calculation unit 3E uses, for example, the angle of the laser beam (beam angle) emitted from the LiDAR 11 to each of the multiple sections, the distance between the LiDAR 11 and each of the multiple sections, and the height of the virtual reflection point included in each of the multiple sections (i.e., the height equivalent to the road surface) to calculate the theoretical value of the reflection points. In other examples, the reflection point calculation unit 3E may calculate the theoretical value of the reflection points by using parameters different from those described above.

[0020] In the example shown in Figure 1, the low-density reflection point area calculation unit 3F calculates a low-density reflection point area, which is an area where the density of reflection points at road surface equivalent height is less than a predetermined value. Specifically, the low-density reflection point area calculation unit 3F determines whether the ratio of the number of road surface equivalent height reflection points to the theoretical value of the number of reflection points is less than a predetermined ratio for each of the multiple areas defined by the area definition unit 3C. If the ratio of the number of road surface equivalent height reflection points to the theoretical value of reflection points is less than a predetermined ratio, the low-density reflection point area calculation unit 3F determines that the density of road surface equivalent height reflection points in that area is less than a predetermined value and calculates that area as a low-density reflection point area (areas shown by hatching in Figure 2). If the ratio of the number of road surface equivalent height reflection points to the theoretical value of reflection points is equal to or greater than a predetermined ratio, the low-density reflection point area calculation unit 3F determines that the density of road surface equivalent height reflection points in that area is equal to or greater than a predetermined value, and calculates that area as an area that is not a low-density reflection point area (in the example shown in Figure 2, the area corresponding to the area in which the LiDAR reflection point group is obtained that is not hatched).

[0021] The road surface detection limit distance calculation unit 3G calculates the shortest distance between the vehicle 1 and the low-density reflection point area (see Figure 2) on the target travel trajectory of the vehicle 1 (see Figure 2) as the detection limit distance (see Figure 2). In the example shown in Figure 2, the road surface detection limit distance calculation unit 3G calculates the detection limit distance as the distance between the vehicle 1 and the three low-density reflection point areas with the shortest distance from the vehicle 1 out of 60 low-density reflection point areas on the target travel trajectory of the vehicle 1.

[0022] In the example shown in Figure 1, the upper limit vehicle speed determination unit 3H determines the upper limit vehicle speed of vehicle 1 based on the detection limit distance calculated by the road surface detection limit distance calculation unit 3G. More specifically, the upper limit vehicle speed determination unit 3H calculates a lower upper limit vehicle speed for vehicle 1 the shorter the detection limit distance calculated by the road surface detection limit distance calculation unit 3G. The control unit 3I performs speed control of the vehicle 1 based on the upper limit vehicle speed determined by the upper limit vehicle speed determination unit 3H. Therefore, in the example shown in Figure 1, the vehicle control device 14 can perform control such as safely stopping the vehicle 1 within the detection limit distance. In other words, in the example shown in Figure 1, if there is a bump, depression, obstacle, etc. on the target driving path of vehicle 1 that vehicle 1 cannot travel on, the vehicle control device 14 will immediately stop the automatic driving of vehicle 1, thereby suppressing the risk of a decrease in the operational rate of the automatic driving system.

[0023] Figure 3 is a flowchart illustrating an example of processing performed by the processor 143 of the vehicle control device 14 in the first embodiment. In the example shown in Figure 3, processing is performed for each section in steps S10 to S18. Specifically, in step S10, the execution of processing for each section begins. In step S11, the section definition unit 3C defines a section in the planar coordinate system of the top view of vehicle 1. In step S12, the road surface equivalent height calculation unit 3D calculates the road surface equivalent height of the section defined in step S11 based on the reflection points detected by the LiDAR 11 (multiple reflection points included in the section defined in step S11). In step S13, the reflection point calculation unit 3E calculates the number of road surface equivalent height reflection points, which are reflection points located at a height within a predetermined range from the road surface equivalent height of the section defined in step S11 (road surface equivalent height calculated in step S12). In step S14, the reflection point calculation unit 3E calculates a theoretical value of reflection points, which is the number of reflection points (virtual reflection points included in the section defined in step S11) located within a predetermined range of height from the equivalent road surface height, assuming that the road surface on which the vehicle 1 traveling within the section defined in step S11 is traveling is at the equivalent road surface height calculated in step S12.

[0024] In step S15, the low-density reflection point area calculation unit 3F determines whether the ratio of the number of reflection points at road surface equivalent height to the theoretical value of reflection points for the area defined in step S11 is less than a predetermined ratio. If the ratio of the number of reflection points at road surface equivalent height to the theoretical value of reflection points is less than the predetermined ratio, the process proceeds to step S16. If the ratio of the number of reflection points at road surface equivalent height to the theoretical value of reflection points is equal to or greater than the predetermined ratio, the process proceeds to step S17. In step S16, the reflection point low-density area calculation unit 3F determines that the area defined in step S11 is a reflection point low-density area. In step S17, the reflection point low-density area calculation unit 3F determines that the area defined in step S11 is not a reflection point low-density area. When the processing in steps S11 to S17 is completed for all of the grid-like sections defined in the planar coordinate system of the top view of vehicle 1, the execution of the processing for each section is completed in step S18.

[0025] In step S19, the road surface detection limit distance calculation unit 3G calculates the shortest distance between the low-density reflection point area on the target driving trajectory of the vehicle 1 and the vehicle 1 as the detection limit distance. In step S20, the upper limit vehicle speed determination unit 3H determines the upper limit vehicle speed of vehicle 1 based on the detection limit distance calculated in step S19. In step S21, the control unit 3I performs speed control of the vehicle 1 based on the upper limit vehicle speed determined in step S20.

[0026] As described above, in a vehicle 1 to which the vehicle control device 14 of the first embodiment is applied, the shortest distance between the low-density reflection point area on the target driving trajectory 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 vehicle speed of the vehicle 1 determined based on the detection limit distance. Therefore, even if an obstacle exists at a distance greater than the detection limit distance from the vehicle 1, when the distance between the vehicle 1 and the obstacle becomes less than the detection limit distance, the vehicle control device 14 can continue the automatic driving of the vehicle 1 while appropriately avoiding collisions between the vehicle 1 and the obstacle. As a result, when a vehicle 1 to which the vehicle control device 14 of the first embodiment is applied is used in an unmanned operation service, the unmanned operation service can be continued with minimal interruption of the unmanned operation.

[0027] <Second Embodiment> A vehicle 1 to which the vehicle control device 14 of the second embodiment is applied is configured in the same way as a vehicle 1 to which the vehicle control device 14 of the first embodiment is applied, except for the points described later.

[0028] As described above, in the example shown in Figure 1, the road surface equivalent height calculation unit 3D calculates the average of the heights of multiple reflection points included in each of the multiple sections defined by the section definition unit 3C as the road surface equivalent height of that section. 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, such as the median or mode, of the heights of multiple reflection points included in each of the multiple sections defined by the section definition unit 3C, as the road surface equivalent height of that section.

[0029] As described above, embodiments of the vehicle control device, vehicle control method, and program of this disclosure have been explained with reference to the drawings. However, the vehicle control device, vehicle control method, and program of this disclosure are not limited to the embodiments described above, and can be modified as appropriate without departing from the spirit of this disclosure. The configurations of each example of the embodiments described above may be combined as appropriate. In each example of the embodiments described above, the processing performed by the vehicle control device 14 was described as software processing performed by executing a program, but the processing performed by the vehicle control device 14 may also be hardware processing. Alternatively, the processing performed by the vehicle control device 14 may be a combination of both software and hardware processing. Furthermore, the program stored in the memory 142 of the vehicle control device 14 (a program that realizes the functions of the processor 143 of the vehicle control device 14) may be recorded on a computer-readable storage medium such as a semiconductor memory, magnetic recording medium, or optical recording medium and provided and distributed. [Explanation of Symbols]

[0030] 1...Vehicle, 11...LiDAR, 12...HMI, 13...Location information acquisition device, 14...Vehicle control device, 141...Communication interface, 142...Memory, 143...Processor, 3A...Acquisition unit, 3B...Detection unit, 3C...Area definition unit, 3D...Road surface equivalent height calculation unit, 3E...Reflection point number calculation unit, 3F...Reflection point low density area calculation unit, 3G...Road surface detection limit distance calculation unit, 3H...Upper limit vehicle speed determination unit, 3I...Control unit, 14A...Steering actuator, 14B...Brake actuator, 14C...Drive actuator

Claims

1. A vehicle control device that performs automatic driving of the vehicle based on the detection results of a LiDAR mounted on the vehicle, A road surface equivalent height calculation unit calculates a road surface equivalent height, which is the height of the road surface on which the vehicle is traveling, based on the reflection points detected by the LiDAR. A reflection point number calculation unit that calculates the number of reflection points, which are reflection points located at a height within a predetermined range from the aforementioned road surface equivalent height, A low-density reflection point area calculation unit calculates a low-density reflection point area which is an area where the density of reflection points at the road surface equivalent height is less than a predetermined value, A road surface detection limit distance calculation unit calculates the shortest distance between the low-density reflection point area on the target travel trajectory of the vehicle and the vehicle as the detection limit distance, A vehicle control device comprising: an upper limit speed determination unit that determines the upper limit speed of the vehicle based on the detection limit distance.

2. The reflection point calculation unit calculates a theoretical value of reflection points, which is the number of reflection points located within a predetermined range from the road surface height while the vehicle is traveling, assuming that the road surface is at a height equivalent to the road surface. The vehicle control device according to claim 1, wherein the low-density reflection point area calculation unit determines that the density of reflection points at road surface equivalent height is less than a predetermined value when the ratio of the number of reflection points at road surface equivalent height to the theoretical value of the number of reflection points is less than a predetermined ratio.

3. The vehicle control device according to claim 2, wherein the low-density reflection point area calculation unit determines whether the ratio of the number of reflection points at road surface equivalent height to the theoretical value of the number of reflection points is less than the predetermined ratio for each of a plurality of grid-like areas defined in a planar coordinate system of the top view of the vehicle.

4. A vehicle control method comprising a vehicle control device that performs automatic driving of the vehicle based on the detection results of a LiDAR mounted on the vehicle, The vehicle control device performs a road surface equivalent height calculation step, which calculates a road surface equivalent height, which is the height of the road surface on which the vehicle is traveling, based on the reflection points detected by the LiDAR. The vehicle control device performs a reflection point calculation step of calculating the number of reflection points, which are reflection points located at a height within a predetermined range from the road surface equivalent height, The vehicle control device performs a low-density reflection point area calculation step, which calculates a low-density reflection point area, which is an area where the density of reflection points at the road surface equivalent height is less than a predetermined value. The vehicle control device performs a road surface detection limit distance calculation step in which it calculates the shortest distance between the low-density reflection point area on the target travel trajectory of the vehicle and the vehicle as the detection limit distance, A vehicle control method comprising: a vehicle control device; a vehicle control device; and a vehicle control device;

5. A processor that performs autonomous driving of the vehicle based on the detection results of the LiDAR installed in the vehicle, A road surface equivalent height calculation step calculates the road surface equivalent height, which is the height corresponding to the road surface on which the vehicle is traveling, based on the reflection points detected by the LiDAR, A step of calculating the number of reflection points, which are reflection points located at a height within a predetermined range from the aforementioned road surface equivalent height, A low-density reflection point area calculation step for calculating a low-density reflection point area, which is an area where the density of reflection points at the road surface equivalent height is less than a predetermined value, A road surface detection limit distance calculation step, which calculates the shortest distance between the low-density reflection point area on the target travel trajectory of the vehicle and the vehicle as the detection limit distance, A program for performing a step of determining the upper limit speed of the vehicle based on the detection limit distance.

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