{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,2,16]],"date-time":"2026-02-16T16:03:03Z","timestamp":1771257783773,"version":"3.50.1"},"reference-count":47,"publisher":"MDPI AG","issue":"21","license":[{"start":{"date-parts":[[2021,10,26]],"date-time":"2021-10-26T00:00:00Z","timestamp":1635206400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Ministry of Education","award":["NRF-2019R1D1A3A03103528"],"award-info":[{"award-number":["NRF-2019R1D1A3A03103528"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>In this paper, a robust observer-based control strategy for n-DOF uncertain robot manipulators with fixed-time stability was developed. The novel fixed-time nonsingular sliding mode surface enables control errors to converge to the equilibrium point quickly within fixed time without singularity. The development of the novel fixed-time disturbance observer based on a uniform robust exact differentiator also allows uncertain terms and exterior disturbances to be proactively addressed. The designed observer can accurately approximate uncertain terms within a fixed time and contribute to significant chattering reduction in the traditional sliding mode control. A robust observer-based control strategy was formulated, according to a combination of the fixed-time nonsingular terminal sliding mode control method and the designed observer, to yield global fixed time stability for n-DOF uncertain robot manipulators. The proposed controller proved definitively that it was able to obtain global stabilization in fixed time. The approximation capability of the proposed observer, the convergence of the proposed sliding surface, and the effectiveness of the proposed control strategy in fixed time were fully confirmed by simulation performance on an industrial robot manipulator.<\/jats:p>","DOI":"10.3390\/s21217084","type":"journal-article","created":{"date-parts":[[2021,10,26]],"date-time":"2021-10-26T23:54:33Z","timestamp":1635292473000},"page":"7084","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":20,"title":["A Robust Observer-Based Control Strategy for n-DOF Uncertain Robot Manipulators with Fixed-Time Stability"],"prefix":"10.3390","volume":"21","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-9361-3919","authenticated-orcid":false,"given":"Anh Tuan","family":"Vo","sequence":"first","affiliation":[{"name":"Department of Electrical, Electronic and Computer Engineering, University of Ulsan, Ulsan 44610, Korea"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-6341-767X","authenticated-orcid":false,"given":"Thanh Nguyen","family":"Truong","sequence":"additional","affiliation":[{"name":"Department of Electrical, Electronic and Computer Engineering, University of Ulsan, Ulsan 44610, Korea"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-9121-5442","authenticated-orcid":false,"given":"Hee-Jun","family":"Kang","sequence":"additional","affiliation":[{"name":"Department of Electrical, Electronic and Computer Engineering, University of Ulsan, Ulsan 44610, Korea"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-9616-6061","authenticated-orcid":false,"given":"Mien","family":"Van","sequence":"additional","affiliation":[{"name":"School of Electronics, Electrical Engineering and Computer Science, Queen\u2019s University Belfast, Belfast BT7 1NN, UK"}]}],"member":"1968","published-online":{"date-parts":[[2021,10,26]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"989","DOI":"10.1016\/S0005-1098(03)00035-9","article-title":"Semiglobal stability of saturated linear PID control for robot manipulators","volume":"39","author":"Kelly","year":"2003","journal-title":"Automatica"},{"key":"ref_2","first-page":"1280","article-title":"Global asymptotic saturated PID control for robot manipulators","volume":"18","author":"Su","year":"2009","journal-title":"IEEE Trans. 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