Method for determining the condition of an aircraft and road surface

Abstract

The present invention provides an aircraft that can reflect the results of its road surface condition assessment into the operation of a vehicle. [Solution] Light 21 shines light onto the road surface. Polarization camera 22 individually detects S-polarized and P-polarized light contained in the reflected light of the light shining onto the road surface. Road surface sensor 26 acquires the direction and degree of the road surface's inclination. Angle adjustment mechanism 24 changes the angle of the light that at least Light 21 shines onto the road surface according to the direction and degree of the road surface's inclination acquired by the road surface sensor 26. Road surface condition determination unit 25 determines the condition of the road surface based on the detected values ​​of S-polarized and P-polarized light detected by the polarization camera.

Description

Technical Field

[0001] The present invention relates to a flying object and a road surface condition determination method.

Background Art

[0002] Patent Document 1 describes mounting a measuring device for measuring the condition of the road surface in front of a vehicle. The measuring device irradiates light from a light projecting unit onto the road surface of the road, and a light receiving unit receives S-polarized light and P-polarized light of scattered light or reflected light from the road surface to determine the condition of the road surface.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] As described in Patent Document 1, the vehicle equipped with the measuring device travels on a road for grasping the condition of the road surface, and the measuring device determines the condition of the road surface directly below the front of the vehicle. Since it does not determine the condition of the road surface dozens of meters ahead of the vehicle, even if the measuring device determines that the road surface is wet or frozen, the determination result cannot be reflected in the driving of the vehicle.

[0005] An object of the present invention is to provide a flying object and a road surface condition determination method capable of reflecting the determination result of the road surface condition in the driving of a vehicle.

Means for Solving the Problems

[0006] The present invention provides an aircraft comprising: a light that illuminates a road surface; a polarization camera that individually detects S-polarized light and P-polarized light contained in the reflected light of the light illuminated on the road surface; a road surface sensor that acquires the direction and degree of the inclination of the road surface; an angle adjustment mechanism that changes at least the angle of the light that illuminates the road surface according to the direction and degree of the inclination of the road surface acquired by the road surface sensor; and a road surface condition determination unit that determines the condition of the road surface based on the detected values ​​of S-polarized light and P-polarized light detected by the polarization camera.

[0007] The present invention provides a road surface condition determination method comprising: flying an aircraft in front of a vehicle traveling on a road at the same speed as the vehicle; illuminating the road surface with a light mounted on the aircraft; detecting S-polarized and P-polarized light contained in the reflected light from the road surface using a polarizing camera mounted on the aircraft; acquiring the direction and degree of the road surface's inclination using a road surface sensor mounted on the aircraft; changing at least the angle of the light illuminating the road surface using an angle adjustment mechanism according to the direction and degree of the road surface's inclination acquired by the road surface sensor; determining the condition of the road surface using a road surface condition determination unit mounted on the aircraft based on the detected values ​​of S-polarized and P-polarized light detected by the polarizing camera; and transmitting the determination result of the road surface condition to an in-vehicle device mounted on the vehicle. [Effects of the Invention]

[0008] According to the present invention, the aircraft and road surface condition determination method make it possible to reflect the determination results of the road surface condition in the operation of the vehicle. [Brief explanation of the drawing]

[0009] [Figure 1] Figure 1 shows an aircraft according to one embodiment flying in front of a vehicle traveling on a road. [Figure 2] Figure 2 is a block diagram showing an aircraft according to one embodiment. [Figure 3]Figure 3 is a plan view of the aircraft as seen from above, with only the main body portion of the aircraft according to one embodiment as a cross-section. [Figure 4] Figure 4 shows the mounting angles of the camera and polarizing camera on an aircraft according to one embodiment. [Figure 5] Figure 5 is a characteristic diagram showing the relationship between the angle of incidence of light incident on the road surface and the reflectance of S-polarized and P-polarized light contained in the reflected light. [Figure 6A] Figure 6A shows the default state when the road surface is a horizontal plane, and the angle adjustment mechanism rotates the mounting body on which the camera and polarizing camera are attached. [Figure 6B] Figure 6B shows a state where the road surface is sloped and the angle adjustment mechanism is rotating the mounting unit. [Figure 7] Figure 7 is a flowchart showing the operation of an aircraft according to one embodiment and a method for determining road surface conditions according to one embodiment. [Modes for carrying out the invention]

[0010] The following describes an aircraft and road surface condition determination method according to one embodiment, with reference to the attached drawings. As shown in Figure 1, vehicle 50 is traveling on road 60. In front of vehicle 50, a drone 100, as an example of an aircraft according to one embodiment, is flying at the same speed as the vehicle 50.

[0011] Figure 2 shows the specific configuration of the drone 100. The drone 100 includes a control unit 10, a memory unit 11, a communication unit 12, a flight sensor 13, motors 14a to 14d, and propellers 15a to 15d. The drone 100 also includes a battery (not shown). These configurations are the basic configuration of a typical drone. The drone 100 further includes a light 21, a polarizing camera 22, a mounting body 23 for attaching the light 21 and the polarizing camera 22, an angle adjustment mechanism 24, a road surface condition determination unit 25, and a road surface sensor 26.

[0012] The vehicle 50 is equipped with an on-board unit 51. The on-board unit 51 includes a communication unit 52 that communicates wirelessly with the communication unit 12. The communication unit 12 and the communication unit 52 communicate with each other according to a predetermined short-range wireless communication standard. When an instruction signal to instruct the drone 100 to fly is input to the communication unit 52, the communication unit 52 transmits the instruction signal to the communication unit 12. The communication unit 12 supplies the received instruction signal to the control unit 10. The control unit 10 controls the motors 14a to 14d to make the drone 100 fly.

[0013] The communication unit 52 also receives information indicating the vehicle's speed and steering angle, and transmits this information to the communication unit 12. The communication unit 12 supplies the received information indicating the vehicle's speed and steering angle to the control unit 10. The control unit 10 controls the motors 14a to 14d so that the drone 100 flies at the same speed as the vehicle 50 and in the direction the vehicle 50 is moving.

[0014] The control unit 10 can be configured as a microprocessor. The memory unit 11 stores a control program that controls each part in order to control the flight of the drone 100 and determine the road surface conditions. The memory unit 11 also temporarily stores the results of the road surface condition determination. The memory unit that stores the control program and the memory unit that temporarily stores the results of the road surface condition determination may be provided separately. In this case, the former and the latter memory units may be of different types.

[0015] The flight sensor 13 includes various sensors such as an acceleration sensor, a gyro sensor, an air pressure sensor, and a magnetic azimuth sensor. The flight sensor 13 may further include a position sensor that receives GNSS signals transmitted from a plurality of satellites for a global navigation satellite system (GNSS (Global Navigation Satellite System)) and calculates the position of the drone 100 based on the received GNSS signals. The flight sensor 13 may further include a sensor called a TOF (Time Of Flight) sensor or LiDAR (Light Detection And Ranging) for maintaining the distance between the drone 100 and the vehicle 50 at a predetermined distance.

[0016] FIG. 3 is a plan view of the drone 100 as seen from above with only a portion of the main body 101 of the drone 100 taken as a cross-section. As shown in FIG. 3, the propellers 15a to 15d are attached to the tip ends of the arms 16a to 16d protruding from the main body 101. The motors 14a to 14d rotate the propellers 15a to 15d according to the control by the control unit 10.

[0017] The mounting body 23 is, for example, a bar, and the lights 21 and the polarized camera 22 are fixed to both ends of the mounting body 23. The angle adjustment mechanism 24 is, for example, a motor. The angle adjustment mechanism 24 adjusts the angles of the lights 21 and the polarized camera 22 with respect to the road surface of the road 60 by rotating the mounting body 23 about the rotation axis 231. In a state where the drone 100 is flying in front of the vehicle 50, the length direction of the mounting body 23 is oriented in a direction orthogonal to the traveling direction of the vehicle 50 (the width direction of the road 60). Therefore, the lights 21 and the polarized camera 22 are arranged side by side in a direction orthogonal to the traveling direction of the vehicle 50.

[0018] As shown in FIG. 4, the light 21 irradiates the road surface of the road 60 with light at an incident angle θ. The light irradiated by the light 21 onto the road surface is, for example, near-infrared laser light. The polarization camera 22 receives the reflected light on the road surface. When the angle adjustment mechanism 24 rotates the mounting body 23, the incident angle θ is adjusted. FIG. 5 shows the relationship between the incident angle of the light incident on the road surface and the reflectance of the S polarization and P polarization included in the reflected light. The solid line is the S polarization, and the broken line is the P polarization.

[0019] Since the reflectances of the S polarization and P polarization differ depending on whether the road surface is dry, wet with rain, or frozen, the characteristics shown in FIG. 5 are characteristics that vary depending on the state of the road surface. The incident angle θ is preferably set to the Brewster angle at which the P polarization becomes zero. If the characteristics shown in FIG. 5 change depending on the state of the road surface, the Brewster angle also changes. In the default state before the angle adjustment mechanism 24 rotates the mounting body 23, assuming that the road surface is a horizontal plane, the incident angle θ may be set within an angular range of ±10 degrees from the Brewster angle based on the Brewster angle in the state where the road surface is dry. In this way, even if the state of the road surface changes, the incident angle θ can be set to an angle near the Brewster angle.

[0020] By the way, the road surface is not necessarily a horizontal plane and may be inclined. Suppose the mounting body 23 to which the light 21 and the polarization camera 22 are fixed is attached to the vehicle 50 in the same manner as in Patent Document 1, and the mounting body 23 is parallel to the horizontal plane of the road surface. Since the vehicle 50 inclines in accordance with the inclination of the road surface even when the road surface is inclined, the mounting body 23 becomes parallel to the inclined road surface. However, when the drone 100 is flying in front of the vehicle 50, the mounting body 23 attached to the drone 100 does not automatically become parallel to the inclined road surface.

[0021] Therefore, the control unit 10 controls the angle adjustment mechanism 24 as follows: The road surface sensor 26 is a TOF sensor or LiDAR, which irradiates a predetermined area of ​​the road surface with light and measures the shape of the predetermined area of ​​the road surface in three dimensions based on the reflected light from the road surface in that predetermined area. As a result, the road surface sensor 26 acquires the direction and degree of the road surface inclination. The control unit 10 controls the angle adjustment mechanism 24 to rotate the mounting body 23 according to the direction and degree of the road surface inclination acquired by the road surface sensor 26.

[0022] Figure 6A shows the default state when the road surface is horizontal and the angle adjustment mechanism 24 rotates the mounting body 23. The mounting body 23 is parallel to the horizontal surface of the road. At this time, the incident angle θ is set within the angle range of Brewster angle ± 10 degrees. Figure 6B shows the state when the road surface is inclined. Here, the inclination of the road surface is exaggerated to make it easier to understand. The control unit 10 controls the angle adjustment mechanism 24 to rotate the mounting body 23 so that it is parallel to the inclined road surface. In Figure 6B, the incident angle θ is maintained within the angle range of Brewster angle ± 10 degrees.

[0023] Returning to Figure 2, the road surface condition determination unit 25 determines the road surface condition based on the detected values ​​of S-polarized light and P-polarized light detected by the polarization camera 22, in accordance with the control by the control unit 10. The road surface condition determination unit 25 has a calculation unit 250. As an example, the calculation unit 250 calculates the P / S ratio by dividing the detected value of P-polarized light by the detected value of S-polarized light. The P / S ratio when the road surface is a puddle or frozen surface where light is specularly reflected will be smaller than the P / S ratio when the road surface is dry asphalt where light is diffusely reflected. The road surface condition determination unit 25 can determine the road surface condition based on the P / S ratio.

[0024] The road surface condition determination unit 25 can be configured as a microprocessor. The control unit 10 and the road surface condition determination unit 25 may be configured as a single microprocessor. The road surface condition determination unit 25 stores the road surface condition determination result in the storage unit 11. The communication unit 12 transmits the determination result stored in the storage unit 11 to the communication unit 52. The in-vehicle unit 51 notifies the driver of the determination result received by the communication unit 52 by displaying it on a display (not shown) or by generating a sound indicating the determination result through a speaker.

[0025] If the drone 100 is flown, for example, several tens of meters in front of the vehicle 50, the driver can reflect the road surface condition determination results in the driving of the vehicle 50. The control unit 10 should control the drone 100 so that the distance between the vehicle 50 and the drone 100 increases as the vehicle 50's speed increases. For example, if the driver is notified that the road surface is frozen and the determination result is that the road surface is frozen, the driver can reduce the speed or make the vehicle 50 move slowly.

[0026] In the configurations shown in Figures 2 and 3, the light 21 and the polarizing camera 22 are fixed to the mounting body 23. By changing the angle of the mounting body 23 using the angle adjustment mechanism 24, the angle of the light that the light 21 shines on the road surface and the angle at which the reflected light enters the polarizing camera 22 are changed. The light 21 and the polarizing camera 22 may be fixed to separate mounting bodies, and the angle of the light that the light 21 shines on the road surface and the angle at which the reflected light enters the polarizing camera 22 may be adjustable separately.

[0027] Since the polarizing camera 22 has a predetermined field of view, it can receive reflected light from the light 21 that shines on the road surface even if the angle of the polarizing camera 22 is slightly off. Therefore, the angle of the polarizing camera 22 may be fixed, and the angle adjustment mechanism 24 may be configured to adjust only the angle of the light that the light 21 shines on the road surface. The angle adjustment mechanism 24 only needs to change the angle of the light that the light 21 shines on the road surface.

[0028] The operation of the drone 100 and the method for determining road surface conditions using the drone 100 will be further explained using the flowchart shown in Figure 7. In Figure 7, the drone 100 starts operating in accordance with instructions from the on-board device 51, and, in accordance with the control of the control unit 10, the drone 100 flies in front of the vehicle 50 traveling on the road 60 at the same speed as the vehicle 50.

[0029] In step S1, the light 21 shines light onto the road surface. In step S2, the polarization camera 22 receives the reflected light. At this time, the polarization camera 22 individually detects the S-polarized and P-polarized light contained in the reflected light of the light shining on the road surface. In step S3, the road surface sensor 26 acquires the direction and degree of the road surface's inclination. In step S4, the control unit 10 adjusts the angle of the mounting body 23 according to the direction and degree of the road surface's inclination acquired by the road surface sensor 26. The control unit 10 only needs to change the angle of the light that the light 21 shines on the road surface.

[0030] In step S5, the road surface condition determination unit 25 determines the road surface condition. In step S6, the storage unit 11 temporarily stores the road surface condition determination result. In step S7, the communication unit 12 transmits the road surface condition determination result to the in-vehicle device 51. In step S8, the control unit 10 determines whether or not to terminate the road surface condition determination. If the road surface condition determination is not terminated (NO), the processes in steps S3 to S8 are repeated. If the road surface condition determination is terminated (YES), the control unit 10 terminates the road surface condition determination by the drone 100.

[0031] As described above, according to the drone 100 as an aerial object and the road surface condition determination method using the drone 100 according to one embodiment, it is possible to reflect the determination result of the road surface condition in the operation of the vehicle 50. One embodiment is suitable for use in a patrol vehicle that patrols the condition of roads where no normal vehicles are driving in advance.

[0032] The present invention is not limited to the embodiments described above, and various modifications are possible without departing from the spirit of the invention. [Explanation of symbols]

[0033] 10 Control Unit 11 Storage section 12,52 Communications Department 13. Flight sensors 14a~14d Motor 15a~15d Propeller 21 Light 22 Polarizing Cameras 23. Wearable body 24 Angle adjustment mechanism 25 Road surface condition determination unit 26 Road surface sensors 50 vehicles 51 Onboard equipment 60 road 100 Drones (Aircraft) 250 Calculation Department

Claims

1. Lights that illuminate the road surface, A polarization camera that separately detects S-polarized and P-polarized light contained in the reflected light of light irradiated onto the road surface, A road surface sensor that acquires the direction and degree of the road surface inclination, An angle adjustment mechanism that changes at least the angle of light that the light emits onto the road surface according to the direction and degree of the road surface inclination acquired by the road surface sensor, A road surface condition determination unit determines the condition of the road surface based on the detected values ​​of S-polarization and P-polarization detected by the polarization camera, An aircraft equipped with [a specific feature / equipment].

2. The light and the polarizing camera are fixed to the mounting body. The angle adjustment mechanism changes the angle of the mounting body, thereby changing the angle of the light that the light shines on the road surface and the angle at which the reflected light enters the polarizing camera. The flying object according to claim 1.

3. The flying object according to claim 1 or 2, wherein the road surface sensor is a sensor that irradiates a predetermined area of ​​the road surface with light and measures the shape of the predetermined area of ​​the road surface in three dimensions based on the reflected light from the road surface in the predetermined area.

4. The aircraft according to claim 1 or 2, wherein the angle adjustment mechanism adjusts the angle of incidence of the light emitted from the light to the road surface within an angle range of the Brewster angle ± 10 degrees.

5. A flying object is made to fly in front of a vehicle traveling on a road at the same speed as the vehicle. The lights mounted on the aircraft illuminate the road surface, A polarization camera mounted on the aircraft detects S-polarized and P-polarized light contained in the reflected light of the light illuminating the road surface separately. The direction and degree of the slope of the road surface are obtained by the road surface sensor mounted on the aircraft. Depending on the direction and degree of the road surface inclination acquired by the road surface sensor, the angle adjustment mechanism changes at least the angle of the light that the light shines on the road surface. The road surface condition determination unit mounted on the aircraft determines the condition of the road surface based on the detected values ​​of S-polarized and P-polarized light detected by the polarization camera. The result of determining the road surface condition is transmitted to the in-vehicle device installed in the vehicle. Method for determining road surface conditions.

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