A Wearable Isokinetic Training Robot for Enhanced Bedside Knee Rehabilitation

Knee pain is prevalent in over 20% of the popula- tion, limiting the mobility of those affected. In turn, isokinetic dy- namometers and robots have been used to facilitate rehabilitation for those still capable of ambulation. However, there are at most only a few wearable robots capable of delivering isokinetic training for bedridden patients. Here, we developed a wearable robot that provides bedside isokinetic training by utilizing a variable stiffness actuator and dynamic energy regeneration. The efficacy of this de- vice was validated in a study involving six subjects with debilitating knee injuries. During two courses of rehabilitation over a total of three weeks, the average peak torque, average torque, and average work produced by their affected knees increased significantly by 81.0%, 101.4%, and 117.6%, respectively. Furthermore, the de- vice’senergyregenerationfeatureswerefoundcapableofextending its operating time to 198 days under normal usage, representing a 57.8% increase over the same device without regeneration. These results suggest potential methodologies for delivering isokinetic joint rehabilitation to bedridden patients in areas with limited infrastructure. Received 31 October 2024; revised 20 January 2025; accepted 11 March 2025. Date of publication 18 March 2025; date of current version 7 April 2025. This work was supported in part by the National Key Research and Development ProgramofChinaunderGrant2022YFB4701200,inpartbytheNationalNatural Science Foundation of China under Grant T2121003 and Grant 62073038, in part by the Innovation & Transfer Fund of Peking University Third Hospital under Grant BYSYZHZB110, in part by the Beijing Institute of Technology Research Funds for High-Level Talents, in part by the Fundamental Research Funds for the Central Universities under Grant YWF-23-L-1205, and in part by the “Scientific Innovation Yongjiang 2035” Key Technology Breakthrough Plan Projects in Ningbo City under Grant 2024Z199. This article was recommended for publication by Associate Editor Z. Li and Editor D. Kulic upon evaluation of the reviewers’ comments. (Yanggang Feng and Xingyu Hu contributed equally to this work.) (Corresponding authors: Yanggang Feng; Liu Wang; Qining Wang; Wuxiang Zhang; Xilun Ding.) This work involved human subjects or animals in its research. Approval of all ethical and experimental procedures and protocols was granted by the Local Ethics Committee of Beihang University, Application No. BM20240173, and performed in line with the Declaration of Helsinki. Yanggang Feng, Xingyu Hu, Yuebing Li, Ke Ma, Jiaxin Ren, Wuxiang Zhang, and Xilun Ding are with the School of Mechanical Engineering and Automation, Beihang University, Beijing 100191, China (e-mail: yang- gangfeng@buaa.edu.cn; zhangwuxiang@buaa.edu.cn; xlding@buaa.edu.cn). Zhihao Zhou and Qining Wang are with the College of Engineering, Peking University, Beijing 100871, China (e-mail: qiningwang@pku.edu.cn). Fuzhen Yuan is with the Department of Sports Medicine, Peking University Third Hospital, Institute of Sports Medicine of Peking University, Beijing 100871, China. Yan Huang is with the School of Mechatronical Engineering, Beijing Institute of Technology, Beijing 100081, China. Liu Wang is with the Department of Modern Mechanics, University of Science and Technology of China, Hefei 230027, China (e-mail: wan- gliu05@ustc.edu.cn). This article has supplementary downloadable material available at https://doi.org/10.1109/TRO.2025.3552332, provided by the authors. Digital Object Identifier 10.1109/TRO.2025.3552332