{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,12]],"date-time":"2025-10-12T04:24:06Z","timestamp":1760243046998,"version":"build-2065373602"},"reference-count":51,"publisher":"MDPI AG","issue":"9","license":[{"start":{"date-parts":[[2015,9,2]],"date-time":"2015-09-02T00:00:00Z","timestamp":1441152000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>This paper presents an algorithm and a system for vertical infrastructure inspection using a vertical take-off and landing (VTOL) unmanned aerial vehicle and shared autonomy. Inspecting vertical structures such as light and power distribution poles is a difficult task that is time-consuming, dangerous and expensive. Recently, micro VTOL platforms (i.e., quad-, hexa- and octa-rotors) have been rapidly gaining interest in research, military and even public domains. The unmanned, low-cost and VTOL properties of these platforms make them ideal for situations where inspection would otherwise be time-consuming and\/or hazardous to humans. There are, however, challenges involved with developing such an inspection system, for example flying in close proximity to a target while maintaining a fixed stand-off distance from it, being immune to wind gusts and exchanging useful information with the remote user. To overcome these challenges, we require accurate and high-update rate state estimation and high performance controllers to be implemented onboard the vehicle. Ease of control and a live video feed are required for the human operator. We demonstrate a VTOL platform that can operate at close-quarters, whilst maintaining a safe stand-off distance and rejecting environmental disturbances. Two approaches are presented: Position-Based Visual Servoing (PBVS) using an Extended Kalman Filter (EKF) and estimator-free Image-Based Visual Servoing (IBVS). Both use monocular visual, inertia, and sonar data, allowing the approaches to be applied for indoor or GPS-impaired environments. We extensively compare the performances of PBVS and IBVS in terms of accuracy, robustness and computational costs. Results from simulations Sensors 2015, 15 22004 and indoor\/outdoor (day and night) flight experiments demonstrate the system is able to successfully inspect and circumnavigate a vertical pole.<\/jats:p>","DOI":"10.3390\/s150922003","type":"journal-article","created":{"date-parts":[[2015,9,3]],"date-time":"2015-09-03T03:10:43Z","timestamp":1441249843000},"page":"22003-22048","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":17,"title":["Inspection of Pole-Like Structures Using a Visual-Inertial Aided VTOL Platform with Shared Autonomy"],"prefix":"10.3390","volume":"15","author":[{"given":"Inkyu","family":"Sa","sequence":"first","affiliation":[{"name":"Science and Engineering Faculty, Queensland University of Technology, Brisbane 4000, Australia"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Stefan","family":"Hrabar","sequence":"additional","affiliation":[{"name":"CSIRO Digital Productivity, Brisbane 4069, Australia"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Peter","family":"Corke","sequence":"additional","affiliation":[{"name":"Science and Engineering Faculty, Queensland University of Technology, Brisbane 4000, Australia"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2015,9,2]]},"reference":[{"key":"ref_1","unstructured":"Echelon Monitored Outdoor Lighting. Available online: http:\/\/info.echelon.com\/Whitepaper-Monitored-Outdoor-Lighting.html."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"636","DOI":"10.1002\/rob.20304","article-title":"CONOPS and autonomy recommendations for VTOL small unmanned aerial system based on Hurricane Katrina operations","volume":"26","author":"Pratt","year":"2009","journal-title":"J. Field Robot."},{"key":"ref_3","unstructured":"Consumer Reports Magazine. Available online: http:\/\/www.consumerreports.org\/cro\/magazine-archive\/may-2009\/may-2009-toc.htm."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"157","DOI":"10.1007\/s10514-005-0723-0","article-title":"Climbing Robots\u2019 Mobility for Inspection and Maintenance of 3D Complex Environments","volume":"18","author":"Balaguer","year":"2005","journal-title":"Auton. Robot."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"65","DOI":"10.1109\/TRO.2007.909786","article-title":"Smooth Vertical Surface Climbing With Directional Adhesion","volume":"24","author":"Kim","year":"2008","journal-title":"IEEE Trans. Robot."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"441","DOI":"10.1002\/rob.20390","article-title":"Cable inspection robot for cable-stayed bridges: Design, analysis, and application","volume":"28","author":"Xu","year":"2011","journal-title":"J. Field Robot."},{"key":"ref_7","doi-asserted-by":"crossref","unstructured":"Haynes, G.C., Khripin, A., Lynch, G., Amory, J., Saunders, A., Rizzi, A.A., and Koditschek, D.E. (2009, January 12\u201317). Rapid Pole Climbing with a Quadrupedal Robot. Proceedings of the IEEE International Conference on Robotics and Automation, Kobe, Japan.","DOI":"10.1109\/ROBOT.2009.5152830"},{"key":"ref_8","doi-asserted-by":"crossref","unstructured":"Parness, A., Frost, M., King, J., and Thatte, N. (2012, January 14\u201318). Demonstrations of gravity-independent mobility and drilling on natural rock using microspines. Proceedings of the IEEE International Conference on Robotics and Automation, Saint Paul, MN, USA.","DOI":"10.1109\/ICRA.2012.6224692"},{"key":"ref_9","doi-asserted-by":"crossref","unstructured":"Ahmadabadi, M., Moradi, H., Sadeghi, A., Madani, A., and Farahnak, M. (2010, January 5\u20137). The evolution of UT pole climbing robots. Proceedings of the 2010 1st International Conference on Applied Robotics for the Power Industry (CARPI), Montreal, QC, Canada.","DOI":"10.1109\/CARPI.2010.5624422"},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"315","DOI":"10.1002\/rob.20414","article-title":"Survey of advances in guidance, navigation, and control of unmanned rotorcraft systems","volume":"29","author":"Kendoul","year":"2012","journal-title":"J. Field Robot."},{"key":"ref_11","doi-asserted-by":"crossref","unstructured":"Voigt, R., Nikolic, J., Hurzeler, C., Weiss, S., Kneip, L., and Siegwart, R. (2011, January 25\u201330). Robust embedded egomotion estimation. Proceedings of the IEEE International Conference on Intelligent Robots and Systems, San Francisco, CA, USA.","DOI":"10.1109\/IROS.2011.6048855"},{"key":"ref_12","doi-asserted-by":"crossref","unstructured":"Burri, M., Nikolic, J., Hurzeler, C., Caprari, G., and Siegwart, R. (2012, January 11\u201313). Aerial service robots for visual inspection of thermal power plant boiler systems. Proceedings of the International Conference on Applied Robotics for the Power Industry, Zurich, Switzerland.","DOI":"10.1109\/CARPI.2012.6473374"},{"key":"ref_13","doi-asserted-by":"crossref","unstructured":"Nikolic, J., Burri, M., Rehder, J., Leutenegger, S., Huerzeler, C., and Siegwart, R. (2013, January 2\u20139). A UAV system for inspection of industrial facilities. Proceedings of the IEEE Aerospace Conference, Big Sky, MT, USA.","DOI":"10.1109\/AERO.2013.6496959"},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"151","DOI":"10.1007\/s10846-013-9852-4","article-title":"Vessel Inspection: A Micro-Aerial Vehicle-based Approach","volume":"76","author":"Ortiz","year":"2013","journal-title":"J. Intell. Robot. Syst."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"319","DOI":"10.1002\/rob.21498","article-title":"A Robot Application for Marine Vessel Inspection","volume":"31","author":"Eich","year":"2014","journal-title":"J. Field Robot."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"644","DOI":"10.1002\/rob.20400","article-title":"RANGE\u2013Robust autonomous navigation in GPS-denied environments","volume":"28","author":"Bachrach","year":"2011","journal-title":"J. Field Robot."},{"key":"ref_17","doi-asserted-by":"crossref","unstructured":"Shen, S., Michael, N., and Kumar, V. (2011, January 9\u201313). Autonomous Multi-Floor Indoor Navigation with a Computationally Constrained MAV. Proceedings of the IEEE International Conference on Robotics and Automation, Shanghai, China.","DOI":"10.1109\/ICRA.2011.5980357"},{"key":"ref_18","unstructured":"Sa, I., and Corke, P. (2013, January 2\u20134). Improved line tracking using IMU and Vision for visual servoing. Proceedings of the Australasian Conference on Robotics and Automation, University of New South Wales, Sydney, Australia."},{"key":"ref_19","unstructured":"Sa, I., Hrabar, S., and Corke, P. (2013, January 9\u201311). Outdoor Flight Testing of a Pole Inspection UAV Incorporating High-Speed Vision. Proceedings of the International Conference on Field and Service Robotics, Brisbane, Australia."},{"key":"ref_20","doi-asserted-by":"crossref","unstructured":"Sa, I., Hrabar, S., and Corke, P. (2014, January 14\u201318). Inspection of Pole-Like Structures Using a Vision-Controlled VTOL UAV and Shared Autonomy. Proceedings of the IEEE International Conference on Intelligent Robots and Systems, Chicago, IL, USA.","DOI":"10.1109\/IROS.2014.6943247"},{"key":"ref_21","doi-asserted-by":"crossref","unstructured":"Sa, I., and Corke, P. (2014, January 27\u201330). Close-quarters Quadrotor flying for a pole inspection with position based visual servoing and high-speed vision. Proceedings of the IEEE International Conference on Unmanned Aircraft Systems, Orlando, FL, USA.","DOI":"10.1109\/ICUAS.2014.6842306"},{"key":"ref_22","unstructured":"Video demonstration. Available online: http:\/\/youtu.be\/ccS85_EDl9A."},{"key":"ref_23","unstructured":"Hough, P. (1959, January 14\u201319). Machine Analysis of Bubble Chamber Pictures. Proceedings of the International Conference on High Energy Accelerators and Instrumentation, Geneva, Switzerland."},{"key":"ref_24","unstructured":"Shi, D., Zheng, L., and Liu., J. (2010). Advanced Hough Transform Using A Multilayer Fractional Fourier Method. IEEE Trans. Image Process."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"23","DOI":"10.1006\/cviu.1997.0586","article-title":"X vision: A portable substrate for real-time vision applications","volume":"69","author":"Hager","year":"1998","journal-title":"Comput. Vis. Image Understand."},{"key":"ref_26","unstructured":"Bartoli, A., and Sturm, P. (2001, January 8\u201314). The 3D line motion matrix and alignment of line reconstructions. Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition, Kauai, USA."},{"key":"ref_27","doi-asserted-by":"crossref","unstructured":"Hartley, R., and Zisserman, A. (2003). Multiple View Geometry in Computer Vision, Cambridge University Press.","DOI":"10.1017\/CBO9780511811685"},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"416","DOI":"10.1016\/j.cviu.2005.06.001","article-title":"Structure-from-motion using lines: Representation, triangulation, and bundle adjustment","volume":"100","author":"Bartoli","year":"2005","journal-title":"Comput. Vis. Image Understand."},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"227","DOI":"10.1109\/TRO.2004.835446","article-title":"Image-based visual servo control of aerial robotic systems using linear image features","volume":"21","author":"Mahony","year":"2005","journal-title":"IEEE Trans. Robot."},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"339","DOI":"10.1007\/s11263-011-0492-5","article-title":"Impact of Landmark Parametrization on Monocular EKF-SLAM with Points and Lines","volume":"97","author":"Civera","year":"2012","journal-title":"Int. J. Comput. Vis."},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"82","DOI":"10.1109\/MRA.2006.250573","article-title":"Visual servo control. I. Basic approaches","volume":"13","author":"Chaumette","year":"2006","journal-title":"IEEE Robot. Autom. Mag."},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"381","DOI":"10.1145\/358669.358692","article-title":"Random sample consensus: A paradigm for model fitting with applications to image analysis and automated cartography","volume":"24","author":"Fischler","year":"1981","journal-title":"Commun. ACM"},{"key":"ref_33","unstructured":"Durrant-Whyte, H. (2001). Introduction to Estimation and the Kalman Filter, The University of Sydney. Technical Report."},{"key":"ref_34","doi-asserted-by":"crossref","unstructured":"Mahony, R., Kumar, V., and Corke, P. (2012). Modeling, Estimation and Control of Quadrotor Aerial Vehicles. IEEE Robot. Autom. Mag.","DOI":"10.1109\/MRA.2012.2206474"},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"28","DOI":"10.1109\/MCS.2013.2287362","article-title":"Quadrotors and Accelerometers: State Estimation with an Improved Dynamic Model","volume":"34","author":"Leishman","year":"2014","journal-title":"IEEE Control Syst."},{"key":"ref_36","unstructured":"Corke, P. (2011). Robotics, Vision & Control: Fundamental Algorithms in MATLAB, Springer."},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"507","DOI":"10.1109\/70.954764","article-title":"A new partitioned approach to image-based visual servo control","volume":"17","author":"Corke","year":"2001","journal-title":"IEEE Trans. Robot. Autom."},{"key":"ref_38","unstructured":"Malis, E., and Rives, P. (2003, January 14\u201319). Robustness of image-based visual servoing with respect to depth distribution errors. Proceedings of the IEEE International Conference on Robotics and Automation, Taipei, Taiwan."},{"key":"ref_39","doi-asserted-by":"crossref","first-page":"313","DOI":"10.1109\/70.143350","article-title":"A new approach to visual servoing in robotics","volume":"8","author":"Espiau","year":"1992","journal-title":"IEEE Trans. Robot. Autom."},{"key":"ref_40","unstructured":"Pissard-Gibollet, R., and Rives, P. (1995, January 21\u201327). Applying visual servoing techniques to control a mobile hand-eye system. Proceedings of the IEEE International Conference on Robotics and Automation, Nagoya, Japan."},{"key":"ref_41","doi-asserted-by":"crossref","unstructured":"Briod, A., Zufferey, J.C., and Floreano, D. (2012, January 14\u201318). Automatically calibrating the viewing direction of optic-flow sensors. Proceedings of the IEEE International Conference on Robotics and Automation, St Paul, MN, USA.","DOI":"10.1109\/ICRA.2012.6225011"},{"key":"ref_42","unstructured":"Corke, P., and Hutchinson, S. (2012, January 14\u201318). Real-time vision, tracking and control. Proceedings of the IEEE International Conference on Robotics and Automation, Saint Paul, MN, USA."},{"key":"ref_43","doi-asserted-by":"crossref","first-page":"691","DOI":"10.1109\/70.88086","article-title":"Vision-guided servoing with feature-based trajectory generation [for robots]","volume":"5","author":"Feddema","year":"1989","journal-title":"IEEE Trans. Robot. Autom."},{"key":"ref_44","unstructured":"Hosoda, K., and Asada, M. (1994, January 12\u201316). Versatile visual servoing without knowledge of true Jacobian. Proceedings of the IEEE International Conference on Intelligent Robot Systems, Munich, Germany."},{"key":"ref_45","doi-asserted-by":"crossref","unstructured":"Omari, S., and Ducard, G. (2013, January 17\u201319). Metric Visual-Inertial Navigation System Using Single Optical Flow Feature. Proceedings of the European Contol Conference, Zurich, Switzerland.","DOI":"10.23919\/ECC.2013.6669273"},{"key":"ref_46","doi-asserted-by":"crossref","unstructured":"Quigley, M., Conley, K., Gerkey, B., Faust, J., Foote, T.B., Leibs, J., Wheeler, R., and Ng, A.Y. (2009, January 12\u201317). ROS: An open-source Robot Operating System. Proceedings of the IEEE International Conference on Robotics and Automation Workshop on Open Source Software, Kobe, Japan.","DOI":"10.1109\/MRA.2010.936956"},{"key":"ref_47","unstructured":"O\u2019Sullivan, L., and Corke, P. (June, January 31). Empirical Modelling of Rolling Shutter Effect. Proceedings of the IEEE International Conference on Robotics and Automation, Hong Kong, China."},{"key":"ref_48","doi-asserted-by":"crossref","unstructured":"Achtelik, M., Achtelik, M., Weiss, S., and Siegwar, R. (2011, January 9\u201313). Onboard IMU and Monocular Vision Based Control for MAVs in Unknown In- and Outdoor Environments. Proceedings of the IEEE International Conference on Robotics and Automation, Shanghai, China.","DOI":"10.1109\/ICRA.2011.5980343"},{"key":"ref_49","unstructured":"Leica TS30. Available online: http:\/\/www.leica-geosystems.com\/en\/Engineering-Monitoring-TPS-Leica-TS30_77093.htm."},{"key":"ref_50","doi-asserted-by":"crossref","unstructured":"Bachrach, A.G. (2009). Autonomous Flight in Unstructured and Unknown Indoor Environments. [Master\u2019s Thesis, MIT].","DOI":"10.1260\/175682909790291492"},{"key":"ref_51","doi-asserted-by":"crossref","unstructured":"Abbeel, P., Coates, A., Montemerlo, M., Ng, A.Y., and Thrun, S. (2005, January 8\u201311). Discriminative Training of Kalman Filters. Proceedings of the Robotics: Science and Systems, Cambridge, MA, USA.","DOI":"10.15607\/RSS.2005.I.038"}],"container-title":["Sensors"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1424-8220\/15\/9\/22003\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T20:47:53Z","timestamp":1760215673000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1424-8220\/15\/9\/22003"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2015,9,2]]},"references-count":51,"journal-issue":{"issue":"9","published-online":{"date-parts":[[2015,9]]}},"alternative-id":["s150922003"],"URL":"https:\/\/doi.org\/10.3390\/s150922003","relation":{},"ISSN":["1424-8220"],"issn-type":[{"type":"electronic","value":"1424-8220"}],"subject":[],"published":{"date-parts":[[2015,9,2]]}}}