{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,4,15]],"date-time":"2026-04-15T00:32:05Z","timestamp":1776213125642,"version":"3.50.1"},"reference-count":33,"publisher":"MDPI AG","issue":"5","license":[{"start":{"date-parts":[[2023,9,29]],"date-time":"2023-09-29T00:00:00Z","timestamp":1695945600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Robotics"],"abstract":"<jats:p>To deploy Unmanned Aerial Vehicles (UAVs) inside heterogeneous GPS-denied confined (potentially unknown) spaces, such as those encountered in mining and Urban Search and Rescue (USAR), requires the enhancement of numerous technologies. Of special interest is for UAVs to identify collision-freeSafe Flight Corridors (SFC+) within highly cluttered convex- and non-convex-shaped environments, which requires UAVs to perform advanced flight maneuvers while exploiting their flying capabilities. Within this paper, a novel auxiliary occupancy checking process that augments traditional 3D flight corridor generation is proposed. The 3D flight corridor is established as a topological structure based on a hand-crafted path either derived from a computer-generated environment or provided by the human operator, which captures humans\u2019 preferences and desired flight intentions for the given space. This corridor is formulated as a series of interconnected overlapping convex polyhedra bounded by the perceived environmental geometries, which facilitates the generation of suitable 3D flight paths\/trajectories that avoid local minima within the corridor boundaries. An occupancy check algorithm is employed to reduce the search space needed to identify 3D obstacle-free spaces in which their constructed polyhedron geometries are replaced with alternate convex polyhedra. To assess the feasibility and efficiency of the proposed SFC+ methodology, a comparative study is conducted against the Star-Convex Method (SCM), a prominent algorithm in the field. The results reveal the superiority of the proposed SFC+ methodology in terms of its computational efficiency and reduced search space for UAV maneuvering solutions. Various challenging confined-environment scenarios, each with different obstacle densities (confined scenarios), are utilized to verify the obtained outcomes.<\/jats:p>","DOI":"10.3390\/robotics12050134","type":"journal-article","created":{"date-parts":[[2023,9,29]],"date-time":"2023-09-29T05:48:13Z","timestamp":1695966493000},"page":"134","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":6,"title":["Three-Dimensional Flight Corridor: An Occupancy Checking Process for Unmanned Aerial Vehicle Motion Planning inside Confined Spaces"],"prefix":"10.3390","volume":"12","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-6468-2587","authenticated-orcid":false,"given":"Sherif","family":"Mostafa","sequence":"first","affiliation":[{"name":"Department of Electrical and Software Engineering, University of Calgary, Calgary, AB T2N 1N4, Canada"}]},{"given":"Alejandro","family":"Ramirez-Serrano","sequence":"additional","affiliation":[{"name":"Department of Mechanical and Manufacturing Engineering, University of Calgary, Calgary, AB T2N 1N4, Canada"}]}],"member":"1968","published-online":{"date-parts":[[2023,9,29]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","unstructured":"Shahmoradi, J., Talebi, E., Roghanchi, P., and Hassanalian, M. (2020). A comprehensive review of applications of drone technology in the mining industry. Drones, 4.","DOI":"10.3390\/drones4030034"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"320","DOI":"10.1007\/s40789-019-00264-5","article-title":"A review of UAV monitoring in mining areas: Current status and future perspectives","volume":"6","author":"Ren","year":"2019","journal-title":"Int. J. Coal Sci. Technol."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"748","DOI":"10.1016\/j.proeng.2017.06.129","article-title":"The use of UAV\u2019s for search and rescue operations","volume":"192","author":"Ptak","year":"2017","journal-title":"Procedia Eng."},{"key":"ref_4","unstructured":"Neubauer, M., G\u00fcnther, G., and F\u00fcllhas, K. (2007). Structural Design Aspects and Criteria for Military UAV, European Aeronautic Defence and Space (EADS). Technical Report."},{"key":"ref_5","first-page":"1646","article-title":"Review of unmanned aircraft system (UAS)","volume":"2","author":"Gupta","year":"2013","journal-title":"Int. J. Adv. Res. Comput. Eng. Technol. (IJARCET)"},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"80","DOI":"10.1016\/j.jocs.2019.04.009","article-title":"Self-organising swarms of firefighting drones: Harnessing the power of collective intelligence in decentralised multi-robot systems","volume":"34","author":"Innocente","year":"2019","journal-title":"J. Comput. Sci."},{"key":"ref_7","unstructured":"CSIRO Head Office, and Westwick-Farrow Pty Ltd. (2023, September 24). Researchers Deploy Autonomous Drone to Improve Operations for Mining Industry. November 2017. Available online: https:\/\/www.processonline.com.au\/content\/business\/news\/researchers-deploy-autonomous-drone-to-improve-operations-for-mining-industry-1267356273."},{"key":"ref_8","unstructured":"Coldewey, D. (2023, September 24). Subterranean Drone Mapping Startup Emesent Raises $2.5 M to Autonomously Delve the Deep. TechCrunch; November 2018. Available online: https:\/\/techcrunch.com\/2018\/11\/05\/subterranean-drone-mapping-startup-emesent-raises-2-5m-to-autonomously-delve-the-deep\/."},{"key":"ref_9","unstructured":"Reporter, S. (2023, September 24). Mapping the Underground with Drones, Legged Robots. Aspermont Media Ltd. October 2018. Available online: https:\/\/www.miningmagazine.com\/innovation\/news\/1347934\/mapping-the-underground-with-drones-legged-robots."},{"key":"ref_10","doi-asserted-by":"crossref","unstructured":"Liang, H., Lee, S.C., Bae, W., Kim, J., and Seo, S. (2023). Towards UAVs in Construction: Advancements, Challenges, and Future Directions for Monitoring and Inspection. Drones, 7.","DOI":"10.3390\/drones7030202"},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"1688","DOI":"10.1109\/LRA.2017.2663526","article-title":"Planning dynamically feasible trajectories for quadrotors using safe flight corridors in 3-d complex environments","volume":"2","author":"Liu","year":"2017","journal-title":"IEEE Robot. Autom. Lett."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"3334","DOI":"10.1109\/LRA.2023.3263376","article-title":"3D-Online Generalized Sensed Shape Expansion: A Probabilistically Complete Motion Planner in Obstacle-Cluttered Unknown Environments","volume":"8","author":"Zinage","year":"2023","journal-title":"IEEE Robot. Autom. Lett."},{"key":"ref_13","unstructured":"Chen, J., Liu, T., and Shen, S. (2016, January 16\u201321). Online generation of collision-free trajectories for quadrotor flight in unknown cluttered environments. Proceedings of the 2016 IEEE International Conference on Robotics and Automation (ICRA), Stockholm, Sweden."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"1526","DOI":"10.1109\/TRO.2020.2993215","article-title":"Teach-repeat-replan: A complete and robust system for aggressive flight in complex environments","volume":"36","author":"Gao","year":"2020","journal-title":"IEEE Trans. Robot."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"1493","DOI":"10.1109\/LRA.2019.2895110","article-title":"Optimal trajectory generation for quadrotor teach-and-repeat","volume":"4","author":"Gao","year":"2019","journal-title":"IEEE Robot. Autom. Lett."},{"key":"ref_16","doi-asserted-by":"crossref","unstructured":"Lien, J.M., and Amato, N.M. (2004, January 9\u201311). Approximate convex decomposition of polygons. Proceedings of the Twentieth Annual Symposium on Computational Geometry, Brooklyn, NY, USA.","DOI":"10.1145\/997817.997823"},{"key":"ref_17","doi-asserted-by":"crossref","unstructured":"Liu, H., Liu, W., and Latecki, L.J. (2010, January 13\u201318). Convex shape decomposition. Proceedings of the 2010 IEEE Computer Society Conference on Computer Vision and Pattern Recognition, San Francisco, CA, USA.","DOI":"10.1109\/CVPR.2010.5540225"},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"654","DOI":"10.1137\/S0097539702405139","article-title":"An approximation algorithm for minimum convex cover with logarithmic performance guarantee","volume":"32","author":"Eidenbenz","year":"2003","journal-title":"SIAM J. Comput."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"636","DOI":"10.1109\/T-C.1975.224276","article-title":"Decomposition of polygons into simpler components: Feature generation for syntactic pattern recognition","volume":"100","author":"Feng","year":"1975","journal-title":"IEEE Trans. Comput."},{"key":"ref_20","doi-asserted-by":"crossref","unstructured":"Deits, R., and Tedrake, R. (2015, January 3\u20135). Computing large convex regions of obstacle-free space through semidefinite programming. Proceedings of the Algorithmic Foundations of Robotics XI: Selected Contributions of the Eleventh International Workshop on the Algorithmic Foundations of Robotics, Istanbul, Turkey.","DOI":"10.1007\/978-3-319-16595-0_7"},{"key":"ref_21","doi-asserted-by":"crossref","unstructured":"Deits, R., and Tedrake, R. (2015, January 26\u201330). Efficient mixed-integer planning for UAVs in cluttered environments. Proceedings of the 2015 IEEE International Conference on Robotics and Automation (ICRA), Washington, DC, USA.","DOI":"10.1109\/ICRA.2015.7138978"},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"53","DOI":"10.1016\/j.ins.2014.09.029","article-title":"Agent-based simulation of building evacuation: Combining human behavior with predictable spatial accessibility in a fire emergency","volume":"295","author":"Tan","year":"2015","journal-title":"Inf. Sci."},{"key":"ref_23","doi-asserted-by":"crossref","unstructured":"Mamou, K., and Ghorbel, F. (2009, January 7\u201310). A simple and efficient approach for 3D mesh approximate convex decomposition. Proceedings of the 2009 16th IEEE International Conference on Image Processing (ICIP), Cairo, Egypt.","DOI":"10.1109\/ICIP.2009.5414068"},{"key":"ref_24","unstructured":"Sarmientoy, A., Murrieta-Cidz, R., and Hutchinsony, S. (2005, January 18\u201322). A sample-based convex cover for rapidly finding an object in a 3-D environment. Proceedings of the 2005 IEEE International Conference on Robotics and Automation, Barcelona, Spain."},{"key":"ref_25","doi-asserted-by":"crossref","unstructured":"Savin, S. (2017, January 29\u201330). An algorithm for generating convex obstacle-free regions based on stereographic projection. Proceedings of the 2017 International Siberian Conference on Control and Communications (SIBCON), Astana, Kazakhstan.","DOI":"10.1109\/SIBCON.2017.7998590"},{"key":"ref_26","unstructured":"Zhong, X., Wu, Y., Wang, D., Wang, Q., Xu, C., and Gao, F. (2020). Generating large convex polytopes directly on point clouds. arXiv."},{"key":"ref_27","unstructured":"Jansen, F., and Ramirez-Serrano, A. (2011, January 12). Extended MPC Strategy for Maneuvering Unmanned Vehicles in Restricted 3D Environments. Proceedings of the Unmanned Systems Canada Conference, Montreal, QC, Canada."},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"119","DOI":"10.1260\/1756-8293.3.3.119","article-title":"Ground\/wall effects on a tilting ducted fan","volume":"3","author":"Hosseini","year":"2011","journal-title":"Int. J. Micro Air Veh."},{"key":"ref_29","unstructured":"Jansen, F. (2011). Manoeuvring Unmanned Vehicles through Confined 3D Environments Using Model Predictive Control. [Master\u2019s Thesis, University of Calgary]."},{"key":"ref_30","unstructured":"Lay, S.R. (2007). Convex Sets and Their Applications, Courier Corporation."},{"key":"ref_31","doi-asserted-by":"crossref","unstructured":"Boyd, S.P., and Vandenberghe, L. (2004). Convex Optimization, Cambridge University Press.","DOI":"10.1017\/CBO9780511804441"},{"key":"ref_32","unstructured":"Cherney, M. (2023, September 24). Drones Are Now Operating Underground: Mining Companies Look to Automation to Help Companies Dig Out More Ore and Save Lives. Kathryn Report Company. Available online: http:\/\/www.kathrynsreport.com\/2017\/11\/drones-are-now-operating-underground.html."},{"key":"ref_33","unstructured":"Hannah Beech, R.C.P., and Suhartono, M. (The New York Times, 2018). Still Can\u2019t Believe It Worked\u2019: The Story of the Thailand Cave Rescue, The New York Times."}],"container-title":["Robotics"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2218-6581\/12\/5\/134\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,10]],"date-time":"2025-10-10T21:01:54Z","timestamp":1760130114000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2218-6581\/12\/5\/134"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2023,9,29]]},"references-count":33,"journal-issue":{"issue":"5","published-online":{"date-parts":[[2023,10]]}},"alternative-id":["robotics12050134"],"URL":"https:\/\/doi.org\/10.3390\/robotics12050134","relation":{},"ISSN":["2218-6581"],"issn-type":[{"value":"2218-6581","type":"electronic"}],"subject":[],"published":{"date-parts":[[2023,9,29]]}}}