{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,3]],"date-time":"2026-09-03T22:12:22Z","timestamp":1788473542938,"version":"build-2803163510"},"reference-count":15,"publisher":"MDPI AG","issue":"3","license":[{"start":{"date-parts":[[2026,3,5]],"date-time":"2026-03-05T00:00:00Z","timestamp":1772668800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100003710","name":"Ministry of Health & Welfare, Republic of Korea","doi-asserted-by":"publisher","award":["RS-2023-00302154"],"award-info":[{"award-number":["RS-2023-00302154"]}],"id":[{"id":"10.13039\/501100003710","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Micromachines"],"abstract":"<jats:p>A capsule endoscope (CE) provides noninvasive access to the gastrointestinal tract, offering diagnostic information that cannot be obtained through external imaging alone. However, during the examination inside the stomach, the CE\u2019s posture may change rapidly as it moves within a dynamically deforming organ, making it difficult to determine its orientation using only the onboard camera feedback. To address this problem, this study proposes a method that employs an external array of Hall Effect Sensors (HES) to estimate the capsule\u2019s position and orientation in real time, based on the magnetic field generated by a permanent magnet (PM) embedded inside the capsule, without the need for any additional internal sensors. This approach introduces a unified magnetic actuation and localization framework that enables real-time 5-degree-of-freedom posture estimation using only the internal PM of the capsule. Furthermore, the proposed system features an integrated architecture capable of simultaneous actuation and localization. To enhance system practicality, the sensor module and communication board were combined into a single unit that employs a digital serial communication scheme, eliminating the need for analog to digital conversion of sensing signals. By avoiding additional onboard sensors and employing a PM-based actuation system, the proposed system simplifies hardware configuration by preserving capsule miniaturization and by eliminating the high power consumption and thermal issues associated with electromagnet-based actuation, while maintaining accurate real-time tracking performance. Through an optimization process, the system achieved a position error of less than 2 mm and an angular error within 2\u00b0 over a sensing range of up to 60 mm. Repeated experiments further validated the system\u2019s effectiveness and reliability under realistic operating conditions, demonstrating its feasibility for compact and clinically applicable active capsule endoscopy systems.<\/jats:p>","DOI":"10.3390\/mi17030327","type":"journal-article","created":{"date-parts":[[2026,3,5]],"date-time":"2026-03-05T11:52:11Z","timestamp":1772711531000},"page":"327","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":1,"title":["Posture Tracking of Active Capsule Endoscopes Integrated with Magnetic Actuation Using Hall-Effect Sensors"],"prefix":"10.3390","volume":"17","author":[{"given":"Junho","family":"Han","sequence":"first","affiliation":[{"name":"Department of Mechanical Engineering, Chonnam National University, Gwangju 61186, Republic of Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-1260-3610","authenticated-orcid":false,"given":"Kim Tien","family":"Nguyen","sequence":"additional","affiliation":[{"name":"Korea Institute of Medical Microrobotics, Gwangju 61011, Republic of Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0006-3549-2561","authenticated-orcid":false,"given":"Eui-Sun","family":"Kim","sequence":"additional","affiliation":[{"name":"Korea Institute of Medical Microrobotics, Gwangju 61011, Republic of Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jong-Oh","family":"Park","sequence":"additional","affiliation":[{"name":"Korea Institute of Medical Microrobotics, Gwangju 61011, Republic of Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Eunho","family":"Choe","sequence":"additional","affiliation":[{"name":"Korea Institute of Medical Microrobotics, Gwangju 61011, Republic of Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-9991-6614","authenticated-orcid":false,"given":"Chang-bae","family":"Moon","sequence":"additional","affiliation":[{"name":"Department of Mechanical Engineering, Chonnam National University, Gwangju 61186, Republic of Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jayoung","family":"Kim","sequence":"additional","affiliation":[{"name":"Department of Biosystems Engineering, Chungbuk National University, Cheongju 28644, Republic of Korea"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2026,3,5]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"169","DOI":"10.1007\/s10776-017-0342-7","article-title":"Fundamental Limits of TOA\/DOA and Inertial Measurement Unit-Based Wireless Capsule Endoscopy Hybrid Localization","volume":"24","author":"Jeong","year":"2017","journal-title":"Int. J. Wirel. Inf. Netw."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"669","DOI":"10.1016\/j.gie.2013.11.022","article-title":"Computerized 3-Dimensional Localization of a Video Capsule in the Abdominal Cavity: Validation by Digital Radiography","volume":"79","author":"Marya","year":"2014","journal-title":"Gastrointest. Endosc."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"23","DOI":"10.1109\/MPRV.2008.17","article-title":"Swallowable-Capsule Technology","volume":"7","author":"McCaffrey","year":"2008","journal-title":"IEEE Pervasive Comput."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"381","DOI":"10.1080\/17434440.2019.1608182","article-title":"Localization strategies for robotic endoscopic capsules: A review","volume":"16","author":"Bianchi","year":"2019","journal-title":"Expert Rev. Med. Devices"},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"357","DOI":"10.1055\/s-0028-1119640","article-title":"Swallowable Capsule Technology: Current Perspectives and Future Directions","volume":"41","author":"Twomey","year":"2009","journal-title":"Endoscopy"},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"11204","DOI":"10.1038\/s41598-021-90523-w","article-title":"A localization method for wireless capsule endoscopy using side wall cameras and IMU sensor","volume":"11","author":"Vedaei","year":"2021","journal-title":"Sci. Rep."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"3819","DOI":"10.1109\/JSEN.2014.2342720","article-title":"DOA-Based Endoscopy Capsule Localization and Orientation Estimation via Unscented Kalman Filter","volume":"14","author":"Goh","year":"2014","journal-title":"IEEE Sens. J."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"1500","DOI":"10.1017\/S0263574722001849","article-title":"Calibrated Analytical Model for Magnetic Localization of Wireless Capsule Endoscope Based on Onboard Sensing","volume":"41","author":"Li","year":"2023","journal-title":"Robotica"},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"708","DOI":"10.1109\/TMECH.2015.2488361","article-title":"A 5-D localization method for a magnetically manipulated untethered robot using a 2-D array of Hall-effect sensors","volume":"21","author":"Son","year":"2015","journal-title":"IEEE\/ASME Trans. Mechatron."},{"key":"ref_10","doi-asserted-by":"crossref","unstructured":"He, M., Zhu, A., and Yang, L. (2025). Electromagnetic Tracking System for Medical Micro Devices: A Review. Micromachines, 16.","DOI":"10.3390\/mi16101175"},{"key":"ref_11","first-page":"7501411","article-title":"A 5-D large-workspace magnetic localization and actuation system based on an eye-in-hand magnetic sensor array and mobile coils","volume":"72","author":"Zhang","year":"2023","journal-title":"IEEE Trans. Instrum. Meas."},{"key":"ref_12","doi-asserted-by":"crossref","unstructured":"Kim, M.-C., Kim, E.-S., Park, J.-O., Choi, E., and Kim, C.-S. (2020). Robotic Localization Based on Planar Cable Robot and Hall Sensor Array Applied to Magnetic Capsule Endoscope. Sensors, 20.","DOI":"10.3390\/s20205728"},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"13424","DOI":"10.1109\/JSEN.2022.3175919","article-title":"6-D Spatial Localization of Wireless Magnetically Actuated Capsule Endoscopes Based on the Fusion of Hall Sensor Array and IMU","volume":"22","author":"Zhang","year":"2022","journal-title":"IEEE Sens. J."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"811","DOI":"10.1109\/TMAG.2012.2205014","article-title":"Optimal Permanent-Magnet Geometries for Dipole Field Approximation","volume":"49","author":"Petruska","year":"2012","journal-title":"IEEE Trans. Magn."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"870","DOI":"10.1109\/TBME.2003.813533","article-title":"Biological Tissue Characterization by Magnetic Induction Spectroscopy (MIS): Requirements and Limitations","volume":"50","author":"Scharfetter","year":"2003","journal-title":"IEEE Trans. Biomed. Eng."}],"container-title":["Micromachines"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2072-666X\/17\/3\/327\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,3,5]],"date-time":"2026-03-05T12:00:33Z","timestamp":1772712033000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2072-666X\/17\/3\/327"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,3,5]]},"references-count":15,"journal-issue":{"issue":"3","published-online":{"date-parts":[[2026,3]]}},"alternative-id":["mi17030327"],"URL":"https:\/\/doi.org\/10.3390\/mi17030327","relation":{},"ISSN":["2072-666X"],"issn-type":[{"value":"2072-666X","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,3,5]]}}}