{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,28]],"date-time":"2026-09-28T23:50:21Z","timestamp":1790639421934,"version":"4.1.0"},"reference-count":55,"publisher":"MDPI AG","issue":"6","license":[{"start":{"date-parts":[[2026,5,29]],"date-time":"2026-05-29T00:00:00Z","timestamp":1780012800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Bioengineering"],"abstract":"<jats:p>Stroke is the second leading cause of death globally and a major contributor to lower-limb disability, affecting gait, balance, and functional independence in elderly populations. While robot-assisted rehabilitation has demonstrated effectiveness in motor recovery, access remains limited due to high costs and geographic barriers, particularly in Latin America. This study presents ExoKnee, a low-cost knee exoskeleton designed through biomimetic principles and 3D-printed fabrication as a proof-of-concept device targeting gait rehabilitation in elderly adults. The system integrates a single-degree-of-freedom pneumatic actuator controlled by electromyography (EMG) signals from the quadriceps muscle, enabling knee flexion and extension (90\u00b0 to 180\u00b0). The design was evaluated through finite element analysis and dynamic simulations in MATLAB\/Simulink R2024a under constant, stepwise, and sinusoidal reference inputs in a digital-twin environment. Expert validation using the Content Validity Coefficient yielded a mean score of 0.8747, reflecting preliminary expert agreement on the conceptual design\u2019s coherence and relevance. The prototype demonstrated controlled movements through a 6-bar pneumatic system with EMG-triggered relay activation, validated at the proof-of-concept level through simulation and single-subject threshold calibration. ExoKnee addresses critical gaps by offering an anthropometrically informed, biosignal-driven, and locally manufacturable rehabilitation platform for low- and middle-income countries, pending clinical validation. Future work will focus on clinical trials and adaptive EMG control strategies.<\/jats:p>","DOI":"10.3390\/bioengineering13060644","type":"journal-article","created":{"date-parts":[[2026,6,3]],"date-time":"2026-06-03T07:58:38Z","timestamp":1780473518000},"page":"644","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":3,"title":["Mechatronic Design and Development of a Lower-Limb Exoskeleton System Based on Knee Joint Biomechanical Principles Using Electro-Pneumatic Actuation with an Embedded EMG Controller for Experimental Validation in Elderly Gait Rehabilitation Support"],"prefix":"10.3390","volume":"13","author":[{"ORCID":"https:\/\/orcid.org\/0009-0000-1151-761X","authenticated-orcid":false,"given":"Adrian","family":"Nacarino","sequence":"first","affiliation":[{"name":"Instituto de Investigaciones en Ciencias Biom\u00e9dicas, Universidad Ricardo Palma, Lima 15039, Peru"},{"name":"Research Group of Advanced Robotics and Mechatronics (GI-ROMA), Ricardo Palma University, Lima 15039, Peru"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Bryan","family":"Sanchez","sequence":"additional","affiliation":[{"name":"Instituto de Investigaciones en Ciencias Biom\u00e9dicas, Universidad Ricardo Palma, Lima 15039, Peru"},{"name":"Professional School of Mechatronics Engineering, Ricardo Palma University, Lima 15039, Peru"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Sandra","family":"Charapaqui","sequence":"additional","affiliation":[{"name":"Instituto de Investigaciones en Ciencias Biom\u00e9dicas, Universidad Ricardo Palma, Lima 15039, Peru"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Renzo","family":"Charapaqui","sequence":"additional","affiliation":[{"name":"Instituto de Investigaciones en Ciencias Biom\u00e9dicas, Universidad Ricardo Palma, Lima 15039, Peru"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0004-5895-3557","authenticated-orcid":false,"given":"Renzo R.","family":"Maldonado-G\u00f3mez","sequence":"additional","affiliation":[{"name":"Instituto de Investigaciones en Ciencias Biom\u00e9dicas, Universidad Ricardo Palma, Lima 15039, Peru"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Leslie M.","family":"Mendoza-Arias","sequence":"additional","affiliation":[{"name":"Instituto de Investigaciones en Ciencias Biom\u00e9dicas, Universidad Ricardo Palma, Lima 15039, Peru"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0007-2986-9243","authenticated-orcid":false,"given":"Daira","family":"de la Barra","sequence":"additional","affiliation":[{"name":"Instituto de Investigaciones en Ciencias Biom\u00e9dicas, Universidad Ricardo Palma, Lima 15039, Peru"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-0328-6895","authenticated-orcid":false,"given":"Cristina","family":"Ccellcaro","sequence":"additional","affiliation":[{"name":"Instituto de Investigaciones en Ciencias Biom\u00e9dicas, Universidad Ricardo Palma, Lima 15039, Peru"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ricardo","family":"Palomares","sequence":"additional","affiliation":[{"name":"Research Group of Advanced Robotics and Mechatronics (GI-ROMA), Ricardo Palma University, Lima 15039, Peru"},{"name":"Professional School of Mechatronics Engineering, Ricardo Palma University, Lima 15039, Peru"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-4096-9337","authenticated-orcid":false,"given":"Jose","family":"Cornejo","sequence":"additional","affiliation":[{"name":"Instituto de Investigaciones en Ciencias Biom\u00e9dicas, Universidad Ricardo Palma, Lima 15039, Peru"},{"name":"Research Group of Advanced Robotics and Mechatronics (GI-ROMA), Ricardo Palma University, Lima 15039, Peru"},{"name":"Space Generation Advisory Council, 1010 Vienna, Austria"},{"name":"Biomimetic Engineering and Aerospace Mechatronics (BEAM) Laboratory, Betta International Corporation, Lima 15026, Peru"},{"name":"Center for Space Systems (C-SET), Betta Aerospace, Betta International Corporation, Lima 15026, Peru"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-9155-9904","authenticated-orcid":false,"given":"Mariela","family":"Vargas","sequence":"additional","affiliation":[{"name":"Instituto de Investigaciones en Ciencias Biom\u00e9dicas, Universidad Ricardo Palma, Lima 15039, Peru"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Robert","family":"Castro","sequence":"additional","affiliation":[{"name":"Professional School of Mechatronics Engineering, Ricardo Palma University, Lima 15039, Peru"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-9703-3340","authenticated-orcid":false,"given":"Jorge","family":"Cornejo","sequence":"additional","affiliation":[{"name":"Mayo Clinic, Jacksonville, FL 32224, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2026,5,29]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","unstructured":"Gobezie, M., Kassa, T., Suliman, J., Eriku, G.A., Takele, M.D., Bitew, D.A., Wubante, S.M., and Kibret, A.K. 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