Investigation system

Abstract

To provide a method of upgrading hovering precision of a flying body even on a floor which is under a non GPS environment, and has no feature point, or has an identical pattern repeated.SOLUTION: An investigation system that flies a flying body under a non GPS environment and performs an environmental investigation includes a flying body that controls flight using information on a shot image taken by a downward camera mounted on a main unit, and a moving body that travels on the ground surface and can tow a cable. The cable is provided with a marker. The flying body controls flight using the marker in the shot image, which is taken by the downward camera, as a feature point.SELECTED DRAWING: Figure 6

Description

[Technical field]

[0001] The present invention relates to a survey system using an aircraft and a mobile object. [Background technology]

[0002] There are inspection / survey methods that use unmanned aerial vehicles to replace inspection and survey work at high risk areas and to improve work efficiency. In environments such as outdoors where GPS position information is available, it is relatively easy to hover an aerial vehicle in the air, that is, to control the flight to keep it in place (horizontal position and altitude). On the other hand, in non-GPS environments such as inside buildings, tunnels, utility tunnels, and sewer pipes, in order to stably hover an aerial vehicle, it is necessary to detect the amount of movement deviation of the aerial vehicle itself and feed it back to the position control system. As a conventional technology for detecting the amount of movement deviation of an aerial vehicle, optical flow technology is known, which captures the ground or floor surface with a camera and detects the amount of movement deviation from the feature points of the captured image.

[0003] For example, a technology such as that described in Patent Document 1 has been disclosed. This is a flying device equipped with a flight propulsion unit and a processing unit, and is equipped with a downward shooting unit that shoots an image in the direction of the ground or floor surface, and a flight sensor unit that detects at least the attitude of the flying device or the altitude relative to the ground or floor surface, and the processing unit performs a trimming process or a reduction process on the image shot by the shooting unit according to the attitude or altitude of the flying device detected by the flight sensor unit, and calculates the horizontal movement amount of the flying device from the image after the trimming process or reduction process. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2019-114008 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, conventional technology is based on the premise that the aircraft flies on a ground or floor with characteristics. Therefore, in a non-GPS environment and on a floor surface without characteristics or with a repeating pattern, it is difficult to detect the amount of deviation in the aircraft's movement using optical flow technology, and there was an issue that the hovering accuracy of the aircraft could not be improved.

[0006] In consideration of the above problems, the present invention aims to provide a method for improving the hovering accuracy of an aircraft even in a non-GPS environment and on a floor surface that has no characteristic points or repeats the same pattern. [Means for solving the problem]

[0007] In view of the above, the present invention is described as "a survey system for conducting environmental surveys by flying an aircraft in a non-GPS environment, comprising an aircraft whose flight is controlled using information from an image captured by a downward camera mounted on the main body, and a mobile body that runs on the ground surface by being able to tow a cable, wherein markers are attached to the cable, and the aircraft's flight is controlled using the markers in the image captured by the downward camera as feature points." Effect of the Invention

[0008] According to the indoor survey system using the flying object and the moving object configured as above, it is possible to improve the hovering accuracy of the flying object even in a non-GPS environment and on a floor surface that has no characteristic points or repeats the same pattern. Problems, configurations, and effects other than those described above will become clear from the description of the following embodiment. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a diagram showing an example of a schematic configuration of an aircraft 100. [Diagram 2] FIG. 1 is a diagram showing an example of the system configuration of an aircraft 100. [Diagram 3]4 is a flowchart showing the flow of horizontal position control (optical flow control) of the aircraft 100. [Figure 4] A diagram showing an aircraft flying over a floor 2 having feature points. [Diagram 5] A figure showing an aircraft flying over a floor 3 that has no feature points. [Figure 6] 1 is a diagram showing a schematic configuration example of an investigation system using an aircraft 100 and a moving body 200 according to a first embodiment. [Figure 7] 2 is a diagram showing an example of an image captured by the downward camera 106 of the flying object 100 when the flying object 100 flew directly above the cable 204. FIG. [Figure 8] FIG. 1 is a configuration diagram of a survey system according to a first embodiment. [Figure 9] 4 is a flowchart showing an investigation procedure of the investigation system according to the first embodiment. [Figure 10] FIG. 13 shows a cable 204 with markers 210 of different colors attached thereto, as described in Example 2. [Figure 11] FIG. 13 is a diagram showing a cable 204 with a marker 211 to which distance information is added, as described in the third embodiment. [Figure 12] FIG. 13 is a diagram showing a configuration example of an investigation system in which a moving body 200 according to a fourth embodiment is capable of moving underwater or on the water surface. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] The indoor survey system using the flying object and the mobile object will be described below with reference to the drawings. In each drawing, the same components are given the same reference numerals, and if the description is repeated, the description may be omitted. In addition, the various components of the present invention do not necessarily have to be independent of each other, and it is acceptable for one component to be made up of multiple parts, for multiple components to be made up of one part, for one component to be a part of another component, or for a part of one component to overlap with a part of another component. EXAMPLES

[0011] First, a basic configuration example of the flying object 100 will be described. Fig. 1 is a diagram showing a schematic configuration example of the flying object 100. The flying object 100 is generally composed of an attitude detection unit 101 such as an IMU (inertial measurement unit), an altitude detection unit 102 such as an air pressure sensor, a laser distance sensor, an ultrasonic sensor, a millimeter wave sensor, etc. that detects the altitude relative to the ground or floor surface, a control unit 103 including a microcomputer that performs signal processing and calculations, a thrust unit 104 consisting of a motor, a propeller, etc., a power source (battery) 105, and a downward camera 106. The downward camera 106 is attached facing downward so as to capture an image of the floor surface 1, and acquires a floor surface image within a downward camera imaging range 107.

[0012] 2 shows an example of the system configuration of the aircraft 100. In addition to the above-mentioned components, the aircraft 100 is equipped with a communication unit 108, which wirelessly communicates with a base station (pilot) operation inputs to the aircraft 100, aircraft status data such as the attitude, altitude, and remaining battery level of the aircraft 100, survey data, and the like.

[0013] Next, the flow of horizontal position control (optical flow control) of the flying object 100 will be explained using the flowchart in Fig. 3. During the horizontal position control, the altitude of the flying object 100 is controlled based on information from the altitude detection unit 102 and is maintained at a constant altitude. These controls are executed by the control unit 103, which is composed of a computer.

[0014] In the flow of Fig. 3, first, the control unit 103 acquires a current image using the lower camera 106 (processing step S1). Next, feature points are extracted from the acquired image (processing step S2). At this time, the presence or absence of feature points is determined (processing step S3), and if there are no feature points in the acquired image, the process returns to processing step S1. If there are feature points in the determination process of processing step S3, the image and the feature points are saved (processing step S4).

[0015] Next, in process step S5, the feature points of the captured image one frame before are compared with the feature points of the current image captured in process step S4, and the horizontal movement amount is calculated in process step S6. After that, in process step S7, it is confirmed whether the horizontal movement amount is equal to or less than the set target value. If the horizontal movement amount is equal to or less than the set target value, horizontal position control is not necessary.

[0016] If the horizontal movement amount is not equal to or less than the set target value (No in process step S7), the difference between the target value and the horizontal movement amount is input to the control unit 103 (process step S8), and the thrust is adjusted (process step S9). For hovering, after the hydraulic adjustment in process step S9, the hovering state is maintained by continuously repeating process steps S1 to S9 during flight. This is the basic flow of horizontal position control of the aircraft 100.

[0017] Fig. 4 is a diagram showing an aircraft flying over a floor 2 having characteristic points. As described above, in order to achieve horizontal position control (optical flow control) in a non-GPS environment, it is essential that there are characteristic points on the floor surface.

[0018] Fig. 5 is a diagram showing an aircraft flying over a floor 3 with no feature points. However, as shown in Fig. 5, when flying over a floor 3 with no feature points, there is no difference in feature points between the image one frame before and the current image, so the horizontal movement amount cannot be calculated, making horizontal position control difficult. Furthermore, in a narrow space surrounded by walls 4 or structures as shown in Fig. 5, the wind emitted by the aircraft 100 itself hits the structures and becomes turbulent, so the attitude of the aircraft tends to be easily shaken or swept away (drift).

[0019] Fig. 6 is a schematic diagram of an indoor survey system using an aircraft 100 and a moving body 200 according to the first embodiment. In this embodiment, the above problem is solved by an indoor survey system using the aircraft 100 and a moving body 200 that is separate from the aircraft 100 shown in Fig. 6. The basic configuration of the present invention is shown in Fig. 6, the system configuration in Fig. 8, and the survey procedure in Fig. 9. The survey environment is an indoor non-GPS environment.

[0020] The flying object 100 has the same configuration as described above, so a description thereof will be omitted. The moving object 200 is generally composed of a crawler 201, a communication unit 202, a camera 203, a cable 204 connected to the moving object 200, a marker 205 attached to or painted on the surface of the cable 204, and a control unit 206 (not shown). The cable 204 includes a power line for the moving object 200, a communication line for the moving object 200, and a communication line for the flying object 100. The marker 205 may be a light such as an LED. As shown in FIG. 6, a cable 204 with a marker 205 towed by the moving object 200 is laid on a floor 3 that does not have a feature point, thereby adding a feature point to the floor 3 that does not have a feature point.

[0021] Fig. 7 is an example of an image captured by the downward camera 106 of the flying object 100 when the flying object 100 flies directly above the cable 204. By using an image having a characteristic point, that is, a cable with a marker, as in Fig. 7, it becomes possible to control the horizontal position of the flying object 100 even on the floor 3, which has no characteristic points.

[0022] 8 is a diagram showing an example of the configuration of an investigation system according to an embodiment of the present invention. The investigation system is composed of a base station 10 with a pilot, a moving body 200, and an aircraft 100.

[0023] Base station 10 has pilot 110A who remotely controls aircraft 100, and pilot 110B who remotely controls moving body 200, and each is equipped with controller 109A and monitor 111A for controlling aircraft 100, and controller 109B and monitor 111B for controlling moving body 200.

[0024] The signal lines of controller 109A and controller 109B and the power line of moving body 200 are bundled together to form cable 204 that is pulled by moving body 200. In moving body 200, control unit 206 controls travel using crawler 201 in response to power and signals from cable 204, and at that time, detects its own position using camera 203. Control unit 206 also communicates with communication unit 108 in flying body 100 via communication unit 202. The flying object 100 is remotely controlled by a pilot 110A via wireless communication with a communication unit 109 of the flying object 100 via a communication unit 202 in the moving object 200. The moving object 200 is also remotely controlled by a pilot 110B via a cable 204.

[0025] With this configuration, when direct wireless communication with the flying object 100 is not possible from the base station 10 due to an obstacle or the like, wireless communication becomes possible via the moving object 200.

[0026] Fig. 9 is a flowchart showing an investigation procedure of the investigation system according to the first embodiment. Next, the investigation procedure will be described with reference to the flowchart in Fig. 9. First, the mobile body 200 departs from the base station 10 (processing step S11). Next, the mobile body 200 is moved to an investigation point (processing step S12). At this time, the cable 204 connected to and pulled by the mobile body 200 is laid on the moving path of the mobile body 200 (processing step S13).

[0027] After the moving body 200 arrives at the investigation point, the flying body 100 takes off from the base station 10 (processing step S4). After taking off, the flying body 100 is moved to a position where the cable 204 laid by the moving body 200 is within the imaging range 107 (FIG. 6) of the downward camera 106 of the flying body 100, and is made to hover over the cable 204 (processing step S15). Thereafter, the flying body 100 is made to fly over the area where the cable 204 is laid (processing step S16), and is made to move to the investigation point (processing step S17). In this way, the cable 204 of the moving body 200 is utilized as a movement path index for the flying body 100.

[0028] The flying object 200 is operated at the investigation point to conduct the investigation (processing step S18). After the investigation, as on the outward journey, it is flown over the cable 204 and moved to the base station 10 (processing step S19), and when the flying object 100 returns to the base station, it is landed (processing step S20). Thereafter, the base station 10 moves the mobile object 200 towards the base station 10 while reeling in the cable 204 of the mobile object 200 (processing step S21). When the mobile object 200 returns to the base station 10 (processing step S22), the investigation is completed. This is the basic investigation procedure.

[0029] In the above-mentioned first embodiment, it is assumed that the aircraft 100 is remotely controlled from the base station 10 by the controller 109 of the pilot 110. However, the aircraft 100 may be provided with a control function to fly autonomously by tracing (line tracing) the cable 204 laid by the moving body 200.

[0030] In addition, the downward camera 106 of the flying object 100 may be an infrared camera in addition to a general camera. In this case, it is possible to capture an image of the heat source of the LED light attached to the cable 204 of the moving object 200 as a characteristic point, and use the image to control the horizontal position of the flying object 100.

[0031] According to the indoor survey system using the aircraft 100 and moving body 200 configured as described above, it is possible to improve the hovering accuracy of the aircraft even in a non-GPS environment and on a floor surface that has no characteristic points or repeats the same pattern. EXAMPLES

[0032] In the first embodiment, as shown in FIG. 6, the cable 204 with the same marker 205 was used. FIG. 10 is a diagram showing the cable 204 with the markers 210 of different colors attached, as described in the second embodiment. In the second embodiment, the markers 205 are markers 210 of different colors as shown in FIG. 10, so that the orientation of the upper and lower ends of the cable 204 can be identified. This makes it possible to determine whether the flying object 100 is currently heading toward the moving object 200 or toward the base station 10, based on the image captured by the downward camera 106. Note that, when the marker 210 is an LED, the orientation of the upper and lower ends of the cable 204 may be identified by changing the color or blinking pattern of the light. EXAMPLES

[0033] When the flying object 100 flies and moves on the cable 204 of the moving object 200, there are cases where it is desired to know the distance to the moving object 200 or the distance to the base station. FIG. 11 is a diagram showing the cable 204 with the marker 211 to which the distance information described in the third embodiment is added. In the third embodiment, as shown in FIG. 11, by using the cable 204 with the marker 211 to which the distance information is added, it is possible to know the distance to the moving object 200 or the base station 10. FIG. 11 shows an example of the cable 204 on which a one-line mark is drawn at a point 10 m from the moving object 200, a two-line mark is drawn at a point 20 m from the moving object 200, and a three-line mark is drawn at a point 30 m from the moving object 200. Instead of such line marks, the cable length information may be indicated by another means, such as a red LED at a point 10 m from the moving object 200 and a blue LED at a point 20 m from the moving object 200. EXAMPLES

[0034] In the first embodiment, an example of the ground-running mobile body 200 is given, but the mobile body 200 may be in a form capable of moving underwater or on the water surface. FIG. 12 is a diagram showing a configuration example of an investigation system in the case where the mobile body 200 described in the fourth embodiment is in a form capable of moving underwater or on the water surface. For example, as shown in FIG. 12, when investigating the inside of a storage tank 5, the mobile body 200 and the flying body 100 are inserted from an insertion port 6, and by using the mobile body 200 capable of moving on the liquid surface 7 and a cable 204 with a buoy (float) 212 connected to the mobile body 200, it is possible to add a feature point on the liquid surface 7 where there is no feature point, and it is possible to realize stable horizontal position control of the flying body 100.

[0035] The survey system of the present invention described above is "a survey system for conducting environmental surveys by flying an aircraft in a non-GPS environment, comprising an aircraft that controls flight using information on images captured by a downward camera mounted on the main body, and a mobile body that travels on the ground surface by being able to pull a cable, a marker is attached to the cable, and the aircraft controls flight using the marker in the images captured by the downward camera as characteristic points." In this case, the ground surface includes not only floors and ground surfaces, but also water surfaces. [Explanation of symbols]

[0036] 1...floor surface, 2...floor with characteristic points, 3...floor without characteristic points, 4...wall surface, 5...storage tank, 6...inlet, 7...liquid level, 10...base station, 100...aircraft vehicle, 101...attitude detection unit, 102...altitude detection unit, 103...control unit, 104...thrust unit, 105...power supply, 106...downward camera, 107...downward camera imaging range, 108...communication unit, 109A, 109B...controller, 110A, 110B...pilot, 111A, 111B...monitor, 112...acquired image, 200...mobile body, 201...crawler, 202...communication unit, 203...camera, 204...cable, 205...marker, 206...control unit, 210...marker of different color, 211...marker with added distance information, 212...buoy

Claims

1. A survey system for conducting environmental surveys by flying an aircraft in a non-GPS environment, comprising: The system includes an aircraft that controls flight using information on images captured by a downward camera mounted on the main body, and a mobile body that travels on the ground surface by being capable of towing a cable. A survey system characterized in that markers are attached to the cables, and the flying object controls flight using the markers as feature points in the images obtained by the downward camera.

2. The survey system of claim 1, An investigation system characterized in that the marker is a distinctive pattern or a plurality of LED lights attached to the surface of a cable of the moving object.

3. The survey system of claim 1, An investigation system characterized in that the flying vehicle identifies the orientation of the upper and lower ends of the cable from the marker.

4. The survey system of claim 1, The survey system is characterized in that the flying vehicle identifies the length of the cable from the marker.

5. The survey system of claim 1, An investigation system characterized in that, prior to flying an aircraft to conduct an environmental investigation, the moving body lays the cable on the ground surface, and the cable of the moving body is used as a movement path indicator for the subsequent aircraft.

6. The survey system of claim 1, The survey system is characterized in that the aircraft has a control function that enables it to fly autonomously by line tracing the cable laid by the moving body.

7. The survey system of claim 1, The downward camera of the flying object is an infrared camera, An investigation system characterized by using the heat source of an LED light attached to the surface of the cable as a feature point.

8. The survey system of claim 1, The survey system is characterized in that the aircraft calculates the horizontal movement amount of the aircraft using the marker in the image captured by the downward camera as a feature point and uses the calculated amount of horizontal movement to control the hovering of the aircraft.

9. The survey system of claim 1, A survey system characterized in that the mobile object is connected to a base station via the cable including a power line and a control signal line, and is supplied with power and remotely controlled to run.

10. The survey system of claim 9, An investigation system characterized in that the mobile body and the aircraft are capable of communicating with each other via a communication unit, and the aircraft flies under remote control from the base station via the cable and the communication unit.

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