AU2016102409A4

AU2016102409A4 - Local Positioning System for an Unmanned Aerial Vehicle

Info

Publication number: AU2016102409A4
Application number: AU2016102409A
Authority: AU
Inventors: Jaeho Lee
Original assignee: Smart Infrastructure Asset Management Australia Res And Development Pty Ltd
Current assignee: Smart Infrastructure Asset Management Australia Research And Development Pty Ltd
Priority date: 2015-02-27
Filing date: 2016-02-29
Publication date: 2019-05-16
Anticipated expiration: 2024-02-29
Also published as: AU2016201290A1

Abstract

The present invention relates to an unmanned aerial vehicle (UAV) for inspecting infrastructure. The UAV includes a drone, and a navigation system including one or more sensors for sensing the infrastructure. The navigation system navigates the drone relative to the sensed infrastructure. The UAV further includes an inspection system transported by the navigated drone and for inspecting the infrastructure. Advantageously, the UAV can maneuver to and inspect hard-to-reach locations of the infrastructure.

Description

LOCAL POSITIONING SYSTEM FOR AN UNMANNED AERIAL VEHICLE

2016102409 29 Feb 2016

TECHNICAL FIELD [0001] The present invention relates to an unmanned aerial vehicle for inspecting infrastructure. The present invention has particular, although not exclusive application to inspecting bridges.

BACKGROUND [0002] The reference to any prior art in this specification is not, and should not be taken as an acknowledgement or any form of suggestion that the prior art forms part of the common general knowledge.

[0003] Bridges such as those used on roadways are periodically inspected for defects by responsible authorities. Many bridge authorities have implemented a Bridge Information System (BIS) or a Bridge Management System (BMS) to manage their routine inspection information. The success of a BIS/BMS is highly dependent on the quality of the bridge inspection results and accurate estimation of future bridge condition ratings.

[0004] Although current routine bridge inspections and Australia’s visual-based inspection method requires a certified inspector to carry out a condition assessment, several limitations have been identified with this manual approach. These limitations include: (1) visual inspections being subjective, depending upon the particular inspector and not always reliable; (2) the entire manual process being costly and time-consuming; (3) a number of safety risks are associated with field inspectors and; (4) an inspection requiring experienced and highly trained personnel. At present, most bridge authorities face the issue of a shortage of inspectors that meet the required level of expertise.

[0005] Furthermore, inspectors are often impeded from reliably inspecting hard-toreach locations such as the underside of bridges. Additionally, bridge defects such as cracks, corrosion, spalling are not measured accurately over time which leads to an imprecise inspection history.

2016102409 29 Feb 2016 [0006] The preferred embodiment provides a means to inspect hard-to-reach locations with greater reliability and consistency.

SUMMARY OF THE INVENTION [0007] According to one aspect of the present invention, there is provided an unmanned aerial vehicle (UAV) for inspecting infrastructure, the UAV including: a drone;

a navigation system including one or more sensors for sensing the infrastructure, and for navigating the drone relative to the sensed infrastructure; and an inspection system transported by the navigated drone and for inspecting the infrastructure.

[0008] Advantageously, the UAV can maneuver to and inspect hard-to-reach locations of the infrastructure. The drone may be accurately and repeatedly navigated relative to the sensed infrastructure during inspection using the onboard sensors, and preferably need not rely on GPS signals which are often unreliable in hard-to-reach locations and less accurate than the sensors. Preferably, the navigation is automated thereby improving inspection accuracy and repeatability.

[0009] Preferably, the navigation system uses the infrastructure as a navigation reference. The sensors may scan the infrastructure for creating a model. The navigation system may navigate by tracking a path derived from the model.

[00010] The inspection system may include a camera for capturing images of the infrastructure. The camera may be rotatably mounted to the drone. The camera may be able to rotate in two axes. The inspection system may capture images at predetermined locations along a navigation path.

[00011] The sensors may include one or more scanners for scanning the infrastructure. The scanners may include laser scanners or sonar scanners. The scanners may include two laser scanners rotating in respective planes. The scanners may rotate up to 270°.

[00012] The UAV may include a flight control system including the navigation system.

The flight control system may further include a collision avoidance system for avoiding

2016102409 29 Feb 2016 collision with objects. The collision avoidance system may include one or more sonar sensors, or the laser sensors, for measuring distance to objects. The flight control system may include a GPS, telemetry and a radio frequency (RF) receiver.

[00013] According to another aspect of the present invention, there is provided an infrastructure inspection system, the inspection system including:

the UAV; and a control system for controlling the UAV.

[00014] Preferably, the control system is in wireless communication with the UAV. The control system may receive scanned infrastructure information from the UAV and create a navigation model using the scanned information. The scanned information may include the distance from the infrastructure to the UAV. The control system may derive a navigation path from the model which is uploaded to the UAV. The navigation system may track the path.

[00015] The drone may be a quadcopter. The drone may include a chassis from which a quartet of arms bearing respective propellers extends. The chassis may bear the flight control system, camera, laser scanners and sonar sensors.

[00016] According to another aspect of the present invention, there is provided an inspection method for inspecting infrastructure using an unmanned aerial vehicle (UAV), the method involving:

sensing the infrastructure;

navigating a drone relative to the sensed infrastructure; and inspecting the infrastructure using an inspection system transported by the navigated drone.

[00017] The step of sensing may involve scanning the infrastructure. The step of navigating may involve navigating using a navigation model created using scanned information. The step of navigating may involve tracking a path derived from the model. The step of inspecting may involve capturing images at predetermined waypoints along a navigation path.

2016102409 29 Feb 2016 [00018] Any of the features described herein can be combined in any combination with any one or more of the other features described herein within the scope of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS [00019] Preferred features, embodiments and variations of the invention may be discerned from the following Detailed Description which provides sufficient information for those skilled in the art to perform the invention. The Detailed Description is not to be regarded as limiting the scope of the preceding Summary of the Invention in any way. The Detailed Description will make reference to a number of drawings as follows:

[00020] Figure 1 is a perspective view of a bridge inspection system in accordance with an embodiment of the present invention;

[00021] Figure 2a is a top view of an unmanned aerial vehicle (UAV) of the system of Figure 1;

[00022] Figure 2b is a bottom view of the UAV of Figure 2a; and [00023] Figure 3 is a flowchart of an inspection method performed using the system of Figure 1.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS [00024] According to an embodiment of the present invention, there is provided a bridge (i.e. infrastructure) inspection system 100 for inspecting a tall bridge 102 as shown in Figure 1. The inspection system 100 includes an unmanned aerial vehicle (UAV) 104 and a remote ground control system 106 for controlling the UAV 104.

[00025] The ground control system 106 is in wireless communication with the UAV 104 via a radio frequency link 108. The ground control system 106 receives scanned bridge information from the UAV 104 and then creates a three-dimensional (3D) navigation model using the scanned information. The scanned information includes the distance from the bridge 102 to the UAV 104. The ground control system 106 derives a navigation path 110, including path waypoints 112 (i.e. 3D co-ordinates), from the model

2016102409 29 Feb 2016 which are uploaded to the UAV 104. The UAV 104 autonomously tracks the path waypoints 112 and captures images of the bridge 102 at predetermined waypoints 112 along the path 110. The UAV 104 moves 50cm horizontally and 30cm vertically between waypoints 112, and advantageously has not more than 10cm drift along the path 110.

[00026] Figure 2 shows the unmanned aerial vehicle (UAV) 104 for inspecting the bridge 102. The UAV 104 includes a drone 200 (e.g. quadcopter) which is able to precisely hover in close proximity to the bridge 102. The drone 200 carries a flight control system 202 including a navigation system 204. The navigation system 204 includes two laser scanners (i.e. sensors) 206, 208 for scanning the bridge 102. The navigation system 204 navigates the drone 200 relative to the scanned bridge 102 along the path 110. A camera inspection system 210 is transported by the navigated drone 200 and includes a high-resolution camera 212 for inspecting the bridge 102.

[00027] Advantageously, the drone 200 can maneuver to and inspect hard-to-reach locations of the bridge 102. The drone 200 is accurately and repeatedly navigated along the path 110 relative to the sensed bridge 102 during inspection using the onboard scanners 206, 208, and need not rely on global positioning system (GPS) signals which are often unreliable in hard-to-reach locations and less accurate than the scanners 206, 208. The navigation is automated along the path 110 thereby improving inspection accuracy and repeatability.

[00028] The camera 212 incrementally captures high-resolution images of the bridge 102 at each predetermined waypoint 112 along the navigation path 110. The camera is rotatably mounted to the top of the drone 200 on a gimbal 214, and can rotate in two axes (i.e. pitch and roll). The pitch can be used when the UAV 104 inspects under the bridge 102 by viewing bridge components vertically upwardly. The roll is used to compensate for the rolling movements of the flying UAV 104 as the camera 212 captures images when pointing level. The camera 212 is further configured to capture images which are streamed, in real time, for display on the ground control system 106 so that an operator can manually inspect the bridge 102 based upon the displayed images.

[00029] The two laser scanners 206, 208 rotate in respective planes, with a horizontal scanner 206 rotating horizontally and a vertical scanner 208 rotating vertically. Each

2016102409 29 Feb 2016 scanner 206, 208 can rotate up to 270° which allows scanning in all directions (i.e. up, down, left, right, front and back). The navigation scanners include the laser scanners 206, 208 and/or sonar scanners 216 described below.

[00030] The flight control system 202 also includes an automated collision avoidance system for avoiding collision with objects. The collision avoidance system includes six distributed sonar sensors 216 for measuring distance to objects. The sensors 216 are located at the chassis corners, top and bottom of the drone 200 to produce reliable measurements. The collision avoidance system may alternatively incorporate the laser sensors 206, 208 for measuring distance to objects, although the sonar sensors 216 advantageously enable signal reflection on water as the UAV 104 passes a river or lake. The sonar sensors 216 can also be used in place of the laser sensors 206, 208 when scanning the bridge102 to form the model and when navigating.

[00031] The flight control system 202 includes the main processor of the UAV 104 for processing all sensor information, and flight commands to achieve precise movement. The flight control system 202 includes a GPS, telemetry and a radio frequency (RF) transceiver in communication with the ground control system 106. The flight control system 202 associates real-time path waypoints 112 with the captured images taken by the camera 212.

[00032] The drone 200 includes a central chassis 217 (or body) from which a quartet of arms 218 extends. Each arm 218 terminates in a motor 220 driving a propeller 222. The chassis 217 bears the flight control system 202, camera 212, laser scanners 206, 208 and sonar sensors 216.

[00033] An inspection method 300 performed using the system 100 of Figure 1 is now described with reference to Figure 3. The method 300 generally involves: step 302 of pre-scanning and modelling the bridge 102; step 304 of configuring the navigation path 110; and step 306 of acquiring images of the bridge 102.

[00034] At step 302, the UAV 104 is initially at a known home location in close proximity to the bridge 102. The operator uses the ground control system 106 to manually navigate the UAV 104 around the bridge. Concurrently, the laser scanners

206, 208 scan the bridge and create scanned information relating to the UAV 104 distance from the bridge 102 at various 3D co-ordinates. The scanned information is

2016102409 29 Feb 2016 transmitted to the ground control system 106 which, in turn, uses the information to form a 3D model of the bridge 102 using simultaneous localization and mapping (SLAM).

[00035] During creation of the 3D model and associated map, the UAV 104 uses its laser scanners 206, 208 to analyse the shapes and sizes of its surrounding components and obstacles in the bridge 102 using triangulation and pulse length modulation. The resulting model allows accurate precision control and hovering along the path 110.

[00036] At step 304, the ground control system 106 uses the 3D model to generate a 3D navigation pathl 10, including 3D path waypoints 112, around the bridge 102. As previously mentioned and shown in Figure 1, the waypoints 112 are the path coordinates where the UAV hovers to capture a bridge portion image using camera 212, and are 50cm horizontally and 30cm vertically spaced apart. The path 110 including waypoints 112 are uploaded from the ground control system 106 to the UAV 104.

[00037] At step 306, the flight control system 202 automatically navigates the drone 200 relative to the bridge 102, sequentially along the path 110 and using the waypoints 112, using real-time information from the lasers 206, 208 for guidance. The flight control system 202 automatically inspects the bridge 102 by capturing images at the waypoints 112 using the camera 212, and associates the waypoint 112 with each image. The collision avoidance system automatically ensures that the UAV 104 does not collide with any objects.

[00038] At step 308, the captured images are exported from the UAV 104 for manual visual inspection by the operator or for further image processing inspection to detect any bridge faults.

[00039] Advantageously, the navigation of the UAV 104 relative to the bridge 102, and using the bridge as a navigation reference, is highly accurate and reliable when compared with using GPS or other known localization techniques. The navigation system can automatically navigate the UAV 104 to any given waypoint 112 with a high degree of repeatability so that the bridge 102 can be accurately monitored over time (e.g. annually). The UAV 104 can reliably inspect bridge locations which are difficult to manually monitor, which is not only safer but avoids the use of expensive equipment (e.g. cranes, scaffolding) which is time consuming to put in place.

2016102409 29 Feb 2016 [00040] A person skilled in the art will appreciate that many embodiments and variations can be made without departing from the ambit of the present invention.

[00041] The present invention can be used for inspecting various types of infrastructure including high rise buildings, tall towers, electricity transmission towers, gantry structures, dams and reservoirs.

[00042] The inspection system of the preferred embodiment visually inspected the infrastructure with a camera.

[00043] In compliance with the statute, the invention has been described in language more or less specific to structural or methodical features. It is to be understood that the invention is not limited to specific features shown or described since the means herein described comprises preferred forms of putting the invention into effect.

[00044] Reference throughout this specification to One embodiment’ or ‘an embodiment’ means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, the appearance of the phrases ‘in one embodiment’ or ‘in an embodiment’ in various places throughout this specification are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more combinations.

Claims

The claims defining the invention are as follows:

1. An unmanned aerial vehicle (UAV) for inspecting infrastructure, the UAV including:

a drone;

a navigation system including one or more sensors for sensing the infrastructure, and for navigating the drone relative to the sensed infrastructure; and an inspection system transported by the navigated drone and for inspecting the infrastructure.
2. An UAV as claimed in claim 1, wherein the drone can be accurately and repeatedly navigated relative to the sensed infrastructure during inspection using the onboard sensors, and preferably need not rely on GPS signals which are often unreliable in hard-to-reach locations and less accurate than the sensors.
3. An UAV as claimed in claim 1 of claim 2, wherein the navigation is automated thereby improving inspection accuracy and repeatability.
4. An UAV as claimed in any one of the preceding claims, wherein the navigation system uses the infrastructure as a navigation reference.
5. An UAV as claimed in any one of the preceding claims, wherein the sensors scan the infrastructure for creating a model.
6. An UAV as claimed in claim 5, wherein the navigation system navigates by tracking a path derived from the model.
7. An UAV as claimed in any one of the preceding claims, further including a camera for capturing images of the infrastructure.
8. An UAV as claimed in claim 7, wherein the camera is rotatably mounted to the drone.
9.

An UAV as claimed in claim 8, wherein the camera is able to rotate in two axes.

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2016102409 29 Feb 2016
10. An UAV as claimed in any one of claims 7 to 9, wherein the inspection system captures images at predetermined locations along a navigation path.
11. An UAV as claimed in any one of the preceding claims, wherein the sensors include one or more scanners for scanning the infrastructure.
12. An UAV as claimed in claim 11, wherein the scanners include laser scanners or sonar scanners.
13. An UAV as claimed in claim 11, wherein the scanners include two laser scanners rotating in respective planes, preferably the scanners can rotate up to 270°.
14. An UAV as claimed in any one of the preceding claims, further including a flight control system including the navigation system.
15. An UAV as claimed in claim 14, wherein the flight control system further includes a collision avoidance system for avoiding collision with objects.
16. An UAV as claimed in claim 15, wherein the collision avoidance system includes one or more sonar sensors, or one or more laser sensors, for measuring distance to objects.
17. An infrastructure inspection system, the inspection system including:

a UAV as claimed in any one of claims 1 to 16; and a control system for controlling the UAV.
18. An infrastructure inspection system as claimed in claim 17, wherein the control system receives scanned infrastructure information from the UAV and create a navigation model using the scanned information.
19. An infrastructure inspection system as claimed in claim 18, wherein the control system derives a navigation path from the model which is uploaded to the UAV so that the navigation system can track the path.
20. An inspection method for inspecting infrastructure using an unmanned aerial vehicle (UAV), the method involving:

π

2016102409 29 Feb 2016 sensing the infrastructure;

navigating a drone relative to the sensed infrastructure; and inspecting the infrastructure using an inspection system transported by the navigated drone.

Dated this 29^th day of February 2016

SMART INFRASTRUCTURE ASSET MANAGEMENT AUSTRALIA RESEARCH AND DEVELOPMENT PTY LTD