Underground tube interior surveying device

Abstract

To provide an underground tube interior surveying device that is solved in or is to solve the problem with a water navigation body type surveying device.SOLUTION: A flight drone 1 comprises a plurality of propeller devices 5, a surveying camera 9, a tracking camera 13, and a plurality of obstacle sensors 15. A disk-like target 19 is prepared. The target 19 is floated on sewage in a sewage pipe and flows downstream. The tracking camera 13 of the flight drone 1 tracks the target 19 and the flight drone 1 flies downstream in the sewage pipe while tracking the movement of the target 19. The surveying camera 9 films an internal wall surface of the sewage pipe during flight.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an inspection device or inspection system for photographing and inspecting the inner wall surface of an underground pipe such as a sewer pipe. [Background technology]

[0002] When photographing and investigating the state of damage inside sewer pipes where water constantly flows, it is often not possible to use an investigation device equipped with wheels. In such cases, if an investigator enters the sewer pipe and attempts to investigate the inside of the pipe using a portable VTR or by visual inspection, the investigation work becomes extremely dangerous due to lack of ventilation and the effects of running water.

[0003] Therefore, as shown in Patent Document 1, an investigation device is constructed by mounting a filming television camera on a surface vehicle, and this investigation device is floated on the flowing water in the sewer pipe and moved inside the pipe while photographing the inner wall surface of the sewer pipe with the filming television camera, and the location and size of cracks occurring in the inner wall of the sewer pipe are investigated based on the photographed results. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 07-216972 Summary of the Invention [Problem to be solved by the invention]

[0005] However, with a surface vehicle-type survey device such as that described in Patent Document 1, there is a risk that the images from the filming television camera will be blurred due to the survey device shaking caused by waves on the water surface, or that water droplets will adhere to the filming surface of the filming television camera, making the images unclear. There is also a risk that the survey device and the filming television camera will capsize due to the impact of waves.

[0006] SUMMARY OF THE PRESENT EMBODIMENTS An object of the present invention is to provide an underground pipe investigation device or investigation system which solves or aims to solve the problems associated with such surface vehicle type investigation devices. [Means for solving the problem]

[0007] To achieve this object, the present invention provides an underground pipe investigation device or system, which is an underground pipe investigation device or system with water flowing inside, and includes a target that moves in the underground pipe in the longitudinal direction, and a flying drone that moves in the underground pipe in the longitudinal direction following the target, the flying drone having a flight propulsion device, an investigation camera for the underground pipe, and a flight control unit that drives and controls the propulsion device, and the flight control unit drives and controls the flight propulsion device so that the flying drone tracks or automatically tracks the target. The flying drone can fly or fly autonomously inside the underground pipe by tracking or automatically tracking the target.

[0008] The target can be configured to move downstream by floating on water and being carried away, and the flight control unit can be configured to drive and control the flight propulsion device so that the flying drone tracks or automatically tracks the target and moves downstream or moves autonomously within the underground pipe.

[0009] The flying drone has a tracking camera that photographs the target, and the flight control unit can drive and control the flight drive device so that the tracking camera continues to photograph the target. The tracking camera continues to photograph the target, so that the flying drone flies inside the underground pipe while following the target.

[0010] The flying drone may have sensors for obstacle avoidance that allow it to fly or fly autonomously within an underground pipe, for example downstream, without coming into contact with or colliding with the inner wall surface of the underground pipe.

[0011] A wire or string may be connected between the target and the flying drone to prevent the flying drone from losing sight of the target or from temporarily losing sight of the target and becoming uncontrollable.

[0012] The wire or strand may be a power supply wire or strand.

[0013] The target may include a light for illuminating the inner wall surface of an underground pipe.

[0014] The flying drone has a drone-side battery and the target has a target-side battery, and the drone-side battery can be configured to be wirelessly charged by the target-side battery. Effect of the Invention

[0015] According to the present invention, it is possible to prevent or improve the influence of flowing water on an investigative camera, or to prevent the camera from being significantly affected by flowing water. [Brief description of the drawings]

[0016] [Figure 1] 1 is a perspective view showing a flying drone and a target that constitute a sewer pipe inspection device or inspection system according to the present invention. FIG. [Diagram 2] FIG. 1 is a schematic diagram of a flying drone and a target moving within a sewer pipe. [Diagram 3] FIG. 1 is a block diagram showing the configuration of a flying drone. [Figure 4] FIG. 13 illustrates another configuration of the target. [Diagram 5] FIG. 1 is a diagram for explaining an outline of the introduction process of the first research method. [Figure 6] FIG. 13 is a diagram for explaining an outline of the investigation process of the first investigation method. [Figure 7] FIG. 13 is a diagram for explaining the collection process of the first research method. [Figure 8] FIG. 13 is a diagram for explaining the introduction process of the second research method. [Figure 9]FIG. 13 is a diagram for explaining an outline of the investigation process of the second investigation method. [Figure 10] FIG. 2 is a schematic diagram illustrating another configuration of an inspection device or system within a sewer pipe. [Figure 11] FIG. 2 is a schematic diagram illustrating a particular inspection aspect of an inspection device or system of another configuration within a sewer pipe. [Figure 12] FIG. 13 is a schematic diagram illustrating another specific inspection aspect of an inspection device or system in another configuration within a sewer pipe. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0018] First, with reference to Figures 1 and 2, a flying drone (unmanned) and a target constituting a sewer pipe inspection device or inspection system according to the present invention will be described.

[0019] The flying drone 1 includes a flying body 3, a plurality of propeller devices (propulsion devices) 5 provided on the flying body 3, an investigation camera 9 with an LED lighting light 7 provided on the front side of the upper surface of the flying body 3, a tracking camera 13 attached to a support device 11 provided on the front side of the lower surface of the flying body 3, a plurality of obstacle sensors 15 provided on the front, upper surface, both sides and lower surface of the flying body 3, and a drone battery 17 that supplies power to each part of the flying drone 1. Four propeller devices 5 are provided here, and each of the obstacle sensors 15 can be an ultrasonic sensor or an infrared sensor, or can be a distance sensor. In addition, the obstacle sensors 15 on the front are provided on both sides in the width direction of the front, and the two obstacle sensors 15 on the front can be configured to function as stereo cameras. Furthermore, a stereo camera may also be provided on the lower surface of the flying body 3. The investigation camera 9 can be, for example, an omnidirectional camera.

[0020] The tracking camera 13 is attached to the support device 11 and is configured to be rotatable up and down (pitch angle direction) and left and right (yaw angle direction) (see arrows). That is, the tracking camera 13 can be driven by the support device 11 to swing up and down, and can be swung left and right by the rotation of the support device 11. Note that the support device 11 can also be configured to swing the tracking camera 13 in the yaw angle direction, pitch angle direction, and roll angle direction.

[0021] The target 19 is, for example, a plastic disk, and the upper surface 21 is formed, for example, in a flat shape, and a triple circle tracking target mark 23 with a quadrant for identifying the target as a tracking target is displayed on the upper surface 21. The target 19 is configured to have a specific gravity of less than 1 so that it floats on the sewage (water) 27 in a sewer pipe (underground pipe) 25.

[0022] The flying drone 1 and the target 19 are introduced into the sewer pipe 25 from the upstream manhole 29, and the flying drone 1 floats in the sewer 27, for example as shown in Fig. 2a, and follows the target 19 moving downstream ahead of it with a tracking camera 13 at a distance from behind, and flies downstream. Alternatively, the flying drone 1 floats in the sewer 27, for example as shown in Fig. 2b, and follows the target 19 moving downstream, and flies downstream, while photographing it with the tracking camera 13 from above or directly above.

[0023] The inspection camera 9 of the flying drone 1 photographs the inner wall surface 31 of the sewer pipe 25 illuminated by the LED lighting light 7 during flight, and the captured image is linked to, for example, location information and recorded in a memory provided in the inspection camera 9.

[0024] After completing the photographing of the inner wall surface 31 of the sewer pipe 25, the flying drone 1 and the target 19 are retrieved from the downstream manhole 33. The recorded survey photographed images can be confirmed after the flying drone 1 is retrieved, for example, by displaying them on a personal computer.

[0025] FIG. 3 is a block diagram showing the configuration of the flying drone 1.

[0026] The flying drone 1 is equipped with a flight control unit 35 consisting of a CPU and RAM or a microcomputer, a memory unit 37, a propeller device 5, a support device 11 for the tracking camera 13, a GPS 39, a barometer 41, a magnetic compass 43, an IMU 45, a communication unit 47, the tracking camera 13, an obstacle sensor 15, and other sensors (not shown).

[0027] The memory unit 37 stores a flight program executed by the flight control unit 35, such as an autonomous flight program. More specifically, the memory unit 37 stores a drive control program for the propeller device 5, a drive control program for the support device 11 of the tracking camera 13, and a program for estimating the movement of the target 19 from the images captured by the tracking camera 13.

[0028] For example, the GPS 39 detects the position of the flying drone 1 outside the sewer pipe 25, the barometer 41 detects, for example, the altitude of the flying drone 1, the magnetic compass 43 detects, for example, the direction of movement of the flying drone 1, and the IMU 45 detects, for example, the attitude and travel distance of the flying drone 1. The flight control unit 35 executes various programs based on the detection results of the GPS 39, the barometer 41, the magnetic compass 43, the IMU 45, etc.

[0029] The communication unit 47 communicates with the controller (proportional system) 49, and in particular receives flight control signals for the flying drone 1 from the controller 49 during the introduction and retrieval processes. The flight control unit 35 executes various programs based on the received flight control signals. The controller 49 has a display 51, and the display 51 displays, for example, an image captured by the tracking camera 13.

[0030] As shown in FIG. 4, if an LED illumination light 53 is provided on, for example, the upper surface 21 of the target 19, the LED illumination light 7 of the flying drone 1 can be omitted. Alternatively, an investigation camera 9 without an LED illumination light 7 can be attached to the flying drone 1. In this case, the upper surface 21 can be bulged, for example, in a cross section of an arc, and a battery 55 for the LED illumination light 53 is attached to the target 19. Here, the triple circle tracking target mark 23 with a quadrant can be displayed on the opposite side of the upper surface 21 of the target 19 from the position where the LED illumination light 53 is arranged. For example, the LED illumination light 53 can be arranged in the front half of the upper surface 21 of the target 19, and the tracking target mark 23 can be displayed in the rear half of the upper surface 21.

[0031] Next, a first inspection method for the inner wall surface 31 of the sewer pipe 25 using the flying drone 1 will be described with reference to Figures 5 to 8.

[0032] (Introduction process) FIG. 5 shows the introduction process. The target 19 is held floating on the sewage 27 near the connection port 57 of the downstream sewer pipe 25 connected to the upstream manhole 29. The controller 49 is connected to the flying drone 1 for communication. The flying drone 1 is controlled by operating the controller 49 to drive and control the propeller device 5 while turning on the power of the investigation camera 9 and checking the display 51 of the controller 49 on which the image captured by the tracking camera 13 is displayed, and the target 19 is moved downward to the lower side of the manhole 29 and put into a hovering state. The target 19 is placed, for example, in the center of the width of the sewer pipe 25. Hovering or hovering and attitude control is performed so that the flying drone 1 is located, for example, in the center of the width of the sewer pipe 25 between the sewer 27 and the upper part of the sewer pipe 25, and the nose of the flying drone 1 (investigation camera 9) faces downstream, for example, in the axial direction (length direction) of the sewer pipe 25 or approximately in the axial direction (length direction).

[0033] The flying drone 1 is positioned in the manhole 29 so as to look into, for example, the sewer pipe 25 (the tracking camera 13 is swung as necessary), and when the target 19 is photographed by the tracking camera 13, the target 19 photographed by the tracking camera 13 and displayed on the display 51 of the controller 49, more precisely, the tracking target mark 23 of the target 19 is identified as the tracking target by surrounding it with a frame 59 on the display 51 (see the enlarged view of the display 51 in FIG. 5). The flying drone 1 stores the identified tracking target mark 23 in, for example, the RAM of the flight control unit 35. The tracking target mark 23 can also be stored in advance in the storage unit 37.

[0034] (Investigative process) Once the tracking target is identified and stored, the controller 49 is operated to switch to automatic (autonomous) flight of the flying drone 1. In automatic flight, the flight control unit 35 controls the propeller device 5 so that the flying drone 1 tracks the tracking target mark 23 of the target 19 from a distance behind while maintaining the distance between the flying drone 1 or the tracking camera 13 and the target 19 and the height of the flying drone 1 when the tracking target is identified, and flies through the sewer pipe 25. The distance between the flying drone 1 and the target 19 can be estimated or detected, for example, by the size of the tracking target mark 23 of the target 19 in the image captured by the tracking camera 13. In addition, the height of the flying drone 1 can be maintained, for example, by the detection result of the barometer 41 and the obstacle sensor 15 arranged on the underside of the flying main body 3. Tracking of the target 19 can be performed by an optical flow sensor system that estimates the movement position of the flying drone 1 or the tracking camera 13 from the movement vector of the tracking target mark 23 in the image captured by the tracking camera 13 and controls the flight. Alternatively, the tracking of the target 19 can be performed by controlling the flight of the flying drone 1 or by controlling the swing of the tracking camera 13 so that the tracking target mark 23 or the center of the tracking target mark 23 is located at the center of the image captured by the tracking camera 13. The flight control unit 35 determines whether the recorded tracking target mark 23 is the same as the mark being tracked.

[0035] The flying drone 1 can fly without touching both sides of the inner wall surface 31 of the sewer pipe 25 by the obstacle sensor 15. The flying drone 1 is controlled to fly inside the sewer pipe 25 while maintaining a constant altitude, but the obstacle sensor 15 provided on the upper surface of the flying body 3 also enables it to fly without touching the upper surface of the inner wall surface 31 of the sewer pipe 25, and the obstacle sensor 15 provided on the lower surface of the flying body 3 also enables it to fly without getting too close to the water surface of the sewer 27 in the sewer pipe 25.

[0036] The obstacle sensor 15 measures the distance to the inner wall surface 31 of the sewer pipe 25, the water surface of the sewer 27, and other obstacles. The flight control unit 35 controls the drive of the propeller device 5 so that the distance measured by the obstacle sensor 15 does not fall below a predetermined value.

[0037] The tracking flight of the flying drone 1 can be performed by the flight control unit 35 controlling the propeller device 5 so that the nose (inspection camera 9) faces the pipe axis direction of the sewer pipe 25 or a direction parallel to the pipe axis. Therefore, as shown in FIG. 6a, even if the position of the target 19 changes or moves from A to B not only in the length direction but also in the width direction, the direction in which the nose of the flying drone 1 faces can be kept parallel to the pipe axis. Also, if the target 19 changes or moves to position C so as to get closer to the inner wall surface 31 of the sewer pipe 25, the measurement distance between the obstacle sensor 15 and the inner wall surface 31 of the sewer pipe 25 becomes shorter, so that the flying drone 1 cannot fly directly behind the target 19. Here, the flight control unit 35 controls the drive of the propeller device 5 and the swing of the tracking camera 13 so that the flying drone 1 flies a certain distance away from the inner wall surface 31 and keeps the direction of its nose parallel to the axis of the sewer pipe 25, and can control the flight of the flying drone 1 so that it tracks the target 19.

[0038] Alternatively, as shown in Figure 6b, the flight control unit 31 may drive and control the propeller device 5 so that the direction in which the nose of the flying drone 1 faces is at an angle to the axis of the sewer pipe 25 without swinging the tracking camera 13, and the flying drone 1 flies in an inclined state, for example, in the direction of the pipe axis or parallel to the pipe axis.

[0039] (Recovery process) When the flying drone 1 finishes photographing and inspecting the inner wall surface 31 of the sewer pipe 25 and the target 19 moves to the downstream manhole 33, the target 19 is pulled up to the ground and collected by, for example, a pulling tool (not shown), as shown in Fig. 7a. During the collection operation of the target 19, the flying drone 1 is connected to the controller 49 and waits in a hovering state near the connection port 57 of the sewer pipe 25 by the controller 49.

[0040] Once the target 19 has been recovered on the ground, as shown in FIG. 7b, the flying drone 1 in a hovering state is controlled by operating the controller 49 while checking the image captured by the tracking camera 13 displayed on the display 51 of the controller 49, and the drone is moved from the manhole 33 to the ground and recovered.

[0041] A second inspection method for the inner wall surface 31 of the sewer pipe 25 using the flying drone 1 will be described with reference to Figures 8, 9 and 7.

[0042] (Introduction process) The target 19 is held floating on the sewage 27 of the upstream manhole 29. The controller 49 is connected to the flying drone 1 for communication. The power of the investigation camera 9 is turned on, and the controller 49 is operated while checking the display 51 of the controller 49 on which the image captured by the tracking camera 13 is displayed, to drive and control the propeller device 5, and the flying drone 1 is moved downward to the lower side of the manhole 29 to hover over the target 19. The target 19 is placed, for example, in the center of the width of the sewer pipe 25. Hovering or hovering and attitude control is performed so that the flying drone 1 is positioned, for example, in the center of the width of the sewer pipe 25 between the target 19 and the upper part of the sewer pipe 25, and the nose of the flying drone 1 (investigation camera 9) faces downstream, for example, in the axial direction (length direction) of the sewer pipe 25 or approximately in the axial direction (length direction) of the sewer pipe 25.

[0043] The flying drone 1 also hovers by swinging the tracking camera 13 downward, for example, so that it faces vertically downward, and by operating the controller 49 while checking the display 51 on which the captured image of the tracking camera 13 is displayed, so that the flying drone 1 or the tracking camera 13 is positioned directly above the target 19. Then, the target 19 captured by the tracking camera 13 and displayed on the display 51 of the controller 49, more precisely, the tracking target mark 23 of the target 19, is specified as the tracking target by surrounding it with a frame 59 on the display 51 (see the enlarged view of the display 51 in FIG. 8). The flying drone 1 stores the specified tracking target mark 23 in, for example, the RAM of the flight control unit 35. The tracking target mark 23 can also be stored in advance in the storage unit 37.

[0044] (Investigative process) When the tracking target is identified, the operation of the controller 49 is switched to automatic (autonomous) flight of the flying drone 1. In automatic flight, the flight control unit 35 drives and controls the propeller device 5 so that the flying drone 1 or the tracking camera 13 is located directly above the target 19, tracks the tracking target mark 23 of the target 19 while maintaining the height of the flying drone 1 from the target 19 when the tracking target is identified, and flies inside the sewer pipe 25. In order to control the flying drone 1 or the tracking camera 13 to fly while being located directly above the target 19, an optical flow sensor system can be used that estimates the moving position of the flying drone 1 or the tracking camera 13 from the moving vector of the tracking target mark 23 in the image captured by the tracking camera 13 facing downward, here vertically downward, and controls the flight. Alternatively, the propeller device 5 is driven and controlled so that the tracking target mark 23 or the center of the tracking target mark 23 is located at the center of the image captured by the tracking camera 13, and the flight of the flying drone 1 is controlled. To maintain the height of the flying drone 1 from the target 19, for example, the flight of the flying drone 1 is controlled so that the size of the tracking target mark 23 of the target 19 in the image captured by the tracking camera 13 is constant. The height of the flying drone 1 can also be maintained by the detection results of the barometer 41 and the obstacle sensor 15 arranged on the underside of the flying body 3. The flight control unit 35 judges whether the recorded tracking target mark 23 is the same as the mark being tracked.

[0045] In addition, when a target 19 capable of generating magnetic force is used and the flying drone 1 is positioned directly above the target 19 to fly in pursuit of the target 19, the drone side battery 17 can be configured to be wirelessly charged by electromagnetic induction in the flying drone 1 due to the magnetic force from the target 19. In this case, the drone side battery 17 can be made small.

[0046] The obstacle sensor 15 enables the flying drone 1 to fly without touching both sides of the inner wall surface 31 of the sewer pipe 25. The flying drone 1 is controlled to fly inside the sewer pipe 25 while maintaining a constant altitude, but the obstacle sensor 15 provided on the upper surface of the flying body 3 also enables it to fly without touching the upper surface of the inner wall surface 31 of the sewer pipe 25, and the obstacle sensor 15 provided on the lower surface of the flying body 3 also enables it to fly without getting too close to the target 19.

[0047] The obstacle sensor 15 measures the distance to the inner wall surface 31 of the sewer pipe 25, the target 19, and other obstacles. The flight control unit 35 controls the drive of the propeller device 5 so that the distance measured by the obstacle sensor 15 does not fall below a predetermined value.

[0048] The tracking flight control of the flying drone 1 can be performed by the flight control unit 35 driving and controlling the propeller device 5 so that the nose (inspection camera 9) faces the pipe axis direction of the sewer pipe 25 or a direction parallel to the pipe axis. Therefore, as shown in FIG. 9a, even if the position of the target 19 changes or moves from A to B not only in the length direction but also in the width direction, the direction in which the nose of the flying drone 1 faces can be kept parallel to the pipe axis. Also, if the target 19 changes or moves to position C so as to get closer to the inner wall surface 31 of the sewer pipe 25, the measurement distance between the target 19 and the inner wall surface 31 of the sewer pipe 25 by the obstacle sensor 15 becomes shorter, so that the flying drone 1 cannot fly directly above the target 19. Here, the flight control unit 35 controls the drive of the propeller device 5 and the swing of the tracking camera 13 so that the flying drone 1 flies a certain distance away from the inner wall surface 31 and keeps the direction of its nose parallel to the axis of the sewer pipe 25, and can switch the flight control of the flying drone 1 so that the flying drone 1 tracks the target 19 from diagonally behind.

[0049] Alternatively, as shown in FIG. 9b, the flight control unit 35 may control the propeller device 5 so that the direction in which the nose of the flying drone 1 faces is at an angle to the axis of the sewer pipe 25 without swinging the tracking camera 13, and the flying drone 1 flies in an inclined state, for example, in the direction of the pipe axis or parallel to the pipe axis.

[0050] (Recovery process) When the flying drone 1 finishes photographing and inspecting the inner wall surface 31 of the sewer pipe 25 and the target 19 and the flying drone 1 move downstream toward the manhole 33, the flying drone 1 communicates with the controller 49 and waits in a hovering state near the connection port 57 of the sewer pipe 25 by the controller 49, as shown in FIG. 7a. Then, when the target 19 that has flown into the manhole 33 is collected on the ground, the flying drone 1 in a hovering state is controlled by operating the controller 49, and is moved from the manhole 33 to the ground and collected, as shown in FIG. 7b.

[0051] Further, another configuration of the investigation device or investigation system in the sewer pipe will be described with reference to Figures 10 to 12. In this modified example, the flying drone 1 or flying body 3 and the target 19 are connected by a wire or string-like body 61, but the other configurations are the same or almost the same as the investigation device before the modification.

[0052] In the investigation device of the modified example, the distance to be maintained between the flying drone 1, flying main body 3, or tracking camera 13 and the target 19 is set by operating the controller 49 to a distance shorter than the length of the wire or string-like body 61. Therefore, as shown in Fig. 10, during normal investigation, the flying drone 1 tracks the target 19 with the wire or string-like body 61 in a slack state. The distance to be maintained between the flying drone 1, flying main body 3, or tracking camera 13 and the target 19 can also be recorded in advance in the memory unit 37.

[0053] In addition, in the investigation device of the modified example, the flying drone 1 is configured to automatically enter a hovering state when the tracking camera 13 loses sight of the tracking target mark 23. With this configuration, for example, as shown in FIG. 11, even if there is a large step between the upstream sewer pipe 63 and the downstream sewer pipe 65 via the manhole 33, the flying drone 1 can continuously investigate the upstream sewer pipe 63 and the downstream sewer pipe 65. That is, when the flying drone 1 finishes investigating the upstream sewer pipe 63, the target 19 and the flying drone 1 jump out from the upstream sewer pipe 63 into the manhole 33, but at this time the tracking camera 13 loses sight of the tracking target mark 23 (for example, the tracking target mark 23 falls out of the shooting range of the tracking camera 13), so the flying drone 1 enters a hovering state. After that, if the weight of the target 19 is sufficient, the flying drone 1 will not be able to maintain the hovering state and will gradually descend inside the manhole 33, and the target 19 will land in the sewer 27 and move downstream. During this time, the tracking camera 13 of the flying drone 1 is driven and controlled, and the position of the flying drone 1 is adjusted to capture the tracking target mark 23 (see the flying drone 1 and target 19 shown by the virtual lines in FIG. 11), and the flying drone 1 is configured to track the target 19 again, allowing the investigation of the downstream sewer pipe 65 to continue.

[0054] Furthermore, if a power supply cable is used as the wire or string-like body 61 and power is supplied from the battery 29 of the target 19 to the flying drone 1, the battery 17 of the flying drone 1 can be omitted.

[0055] 12, if the target 19 moves instantaneously from position (A) to position (B) where the wire or string-like body 61 is stretched and taut due to the influence of muddy water or strong currents, the tracking camera 13 will lose sight of the tracking target mark 23, and the flying drone 1 will enter a hovering state. If the tracking camera 13 of the flying drone 1 is driven and controlled and the position of the flying drone 1 is adjusted to capture the tracking target mark 23, the flying drone 1 will be configured to track the target 19 again, and the investigation of the sewer pipe 25 can be continued. [Explanation of symbols]

[0056] 1. Flying drone 5 Propeller device 9. Survey Camera 19 Target 25 Sewer pipe 27 Sewer 31 Inner wall surface 35 Flight Control Unit

Claims

1. An investigation device for an underground pipe through which water flows, a target moving longitudinally within the underground pipe; a flying drone that moves longitudinally within the underground pipe following the target; The flying drone has a flight propulsion device, an investigation camera for the underground pipe, and a flight control unit that drives and controls the propulsion device, An investigation device for underground pipes, characterized in that the flight control unit drives and controls the flight propulsion device so that the flying drone tracks the target.

2. The target moves downstream by floating on water, 2. The underground pipe investigation device according to claim 1, wherein the flying drone moves downstream within the underground pipe while tracking the target.

3. The flying drone has a tracking camera that photographs the target, 3. The underground pipe investigation device according to claim 1, wherein the flight control unit drives and controls the flight drive device so that the tracking camera continues to photograph the target.

4. 3. The underground pipe investigation device according to claim 1 or 2, wherein the flying drone has a sensor for obstacle avoidance.

5. 3. An underground pipe investigation device as described in claim 1 or 2, characterized in that a wire or string-like object is connected between the target and the flying drone to prevent the flying drone from losing sight of the target or temporarily losing sight of the target and becoming uncontrollable.

6. 6. The underground pipe investigation device according to claim 5, wherein the wire or string-like member is a wire or string-like member for supplying electric power.

7. 3. The underground pipe investigation device according to claim 1, wherein the target has a light for illuminating an inner wall surface of the underground pipe.

8. The flying drone has a drone-side battery, and the target has a target-side battery; 3. The underground pipe investigation device according to claim 1 or 2, wherein the drone-side battery is wirelessly charged by the target-side battery.

Images