{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,8,4]],"date-time":"2026-08-04T04:45:28Z","timestamp":1785818728991,"version":"3.56.0"},"reference-count":31,"publisher":"MDPI AG","issue":"15","license":[{"start":{"date-parts":[[2026,8,2]],"date-time":"2026-08-02T00:00:00Z","timestamp":1785628800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100002969","name":"Technology Agency of the Czech Republic","doi-asserted-by":"publisher","award":["TQ15000023"],"award-info":[{"award-number":["TQ15000023"]}],"id":[{"id":"10.13039\/501100002969","id-type":"DOI","asserted-by":"publisher"}]},{"award":["TQ15000023"],"award-info":[{"award-number":["TQ15000023"]}],"id":[{"id":"https:\/\/ror.org\/04v0fk911","id-type":"ROR","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100013855","name":"European Union","doi-asserted-by":"publisher","award":["CZ.10.03.01\/00\/22\\_003\/0000048"],"award-info":[{"award-number":["CZ.10.03.01\/00\/22\\_003\/0000048"]}],"id":[{"id":"10.13039\/501100013855","id-type":"DOI","asserted-by":"publisher"}]},{"award":["CZ.10.03.01\/00\/22\\_003\/0000048"],"award-info":[{"award-number":["CZ.10.03.01\/00\/22\\_003\/0000048"]}],"id":[{"id":"https:\/\/ror.org\/019w4f821","id-type":"ROR","asserted-by":"publisher"}]},{"name":"Student Grant System, VSB-TU Ostrava","award":["SP2025\/019"],"award-info":[{"award-number":["SP2025\/019"]}]},{"DOI":"10.13039\/501100008530","name":"European Regional Development Fund","doi-asserted-by":"crossref","award":["CZ.02.1.01\/0.0\/0.0\/17_049\/0008425"],"award-info":[{"award-number":["CZ.02.1.01\/0.0\/0.0\/17_049\/0008425"]}],"id":[{"id":"10.13039\/501100008530","id-type":"DOI","asserted-by":"crossref"}]},{"award":["CZ.02.1.01\/0.0\/0.0\/17_049\/0008425"],"award-info":[{"award-number":["CZ.02.1.01\/0.0\/0.0\/17_049\/0008425"]}],"id":[{"id":"https:\/\/ror.org\/01rkhv978","id-type":"ROR","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>This article presents a sensorless method for cycle-level payload mass estimation in industrial robots using internal motor-current signals only. The approach is based on automated KUKA Trace acquisition of six-axis current traces from a KUKA KR3 controller, followed by statistical feature extraction and regression using a multilayer perceptron (MLP). Experiments were conducted on two nominally identical KUKA KR3 R540 manipulators under a repeatable handling motion with payloads ranging from approximately 0.4 kg to 2.6 kg, enabling the systematic engineering validation of controller-based current acquisition, feature-based payload regression, and cross-robot validation. This study investigated whether motor-current signals could serve as a reliable virtual sensing source without external force or weight sensors. Under repeated operating conditions, the most accurate MLP configuration achieved a testing mean absolute error (MAE) of 6.75 g and a mean squared error (MSE) of 68.28 g2. With mixed-source training, using data from both robots, the testing MAE decreased to 5.37 g, and the accuracy within a \u00b115 g tolerance reached 96.88%. In contrast, direct transfer to another nominally identical robot increased the MAE to 80.54 g, revealing a clear cross-robot generalization gap. Overall, this study demonstrates the feasibility of motor-current-based payload verification during repeated single-axis motion under controlled conditions and indicates its potential for gripping validation and missing-part detection in industrial handling applications.<\/jats:p>","DOI":"10.3390\/s26154867","type":"journal-article","created":{"date-parts":[[2026,8,3]],"date-time":"2026-08-03T11:50:21Z","timestamp":1785757821000},"page":"4867","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Sensorless Payload Estimation in an Industrial Robot Using Internal Motor-Current Signals"],"prefix":"10.3390","volume":"26","author":[{"ORCID":"https:\/\/orcid.org\/0009-0009-2590-7737","authenticated-orcid":false,"given":"Adam","family":"B\u00e1trla","sequence":"first","affiliation":[{"name":"Department of Cybernetics and Biomedical Engineering, Faculty of Electrical Engineering and Computer Science, VSB\u2014Technical University of Ostrava, 708 00 Ostrava, Czech Republic"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-8657-275X","authenticated-orcid":false,"given":"Ojan","family":"Majidzadeh Gorjani","sequence":"additional","affiliation":[{"name":"Department of Cybernetics and Biomedical Engineering, Faculty of Electrical Engineering and Computer Science, VSB\u2014Technical University of Ostrava, 708 00 Ostrava, Czech Republic"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-5641-4670","authenticated-orcid":false,"given":"Radek","family":"Byrtus","sequence":"additional","affiliation":[{"name":"Department of Cybernetics and Biomedical Engineering, Faculty of Electrical Engineering and Computer Science, VSB\u2014Technical University of Ostrava, 708 00 Ostrava, Czech Republic"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-8292-225X","authenticated-orcid":false,"given":"Radim","family":"Herc\u00edk","sequence":"additional","affiliation":[{"name":"Department of Cybernetics and Biomedical Engineering, Faculty of Electrical Engineering and Computer Science, VSB\u2014Technical University of Ostrava, 708 00 Ostrava, Czech Republic"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2026,8,2]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"1915","DOI":"10.1007\/s41315-025-00478-8","article-title":"Real-time monitoring and prediction applications of industrial robots using machine learning","volume":"9","author":"Zheng","year":"2025","journal-title":"Int. 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