{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,21]],"date-time":"2026-09-21T14:48:59Z","timestamp":1790002139595,"version":"4.0.1"},"reference-count":45,"publisher":"MDPI AG","issue":"2","license":[{"start":{"date-parts":[[2026,2,1]],"date-time":"2026-02-01T00:00:00Z","timestamp":1769904000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Shanghai Sailing Program","award":["23YF1414000"],"award-info":[{"award-number":["23YF1414000"]}]},{"DOI":"10.13039\/501100012226","name":"Fundamental Research Funds for the Central Universities","doi-asserted-by":"crossref","award":["020414380195"],"award-info":[{"award-number":["020414380195"]}],"id":[{"id":"10.13039\/501100012226","id-type":"DOI","asserted-by":"crossref"}]},{"name":"State Key Laboratory of Acoustics, Chinese Academy of Sciences","award":["SKLA202411"],"award-info":[{"award-number":["SKLA202411"]}]},{"name":"horizontal project \u201cDevelopment of Garbage Fine Sorting Equipment Based on Machine Vision\u201d","award":["2025620001004278"],"award-info":[{"award-number":["2025620001004278"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Biomimetics"],"abstract":"<jats:p>Upper limb rehabilitation exoskeletons form a spatial closed kinematic chain with the human arm, where inevitable joint-center and axis misalignment can generate hyperstatic interaction forces and torques. Passive degrees of freedom (DOF) are widely introduced to improve kinematic compatibility, yet different compatible configurations may exhibit distinct wearable performance. This study experimentally compares three compatible four-degree-of-freedom exoskeleton configurations derived from the synthesis of Li et al. using a single reconfigurable rehabilitation robot. The platform is assembled into each configuration through modular passive units and instrumented with two six-axis force\u2013torque sensors at the upper-arm and forearm interfaces. Interaction forces and torques are measured in passive training mode during eating and combing trajectories. For each configuration, tests are performed with passive joints released and with passive joints locked to quantify the effect of passive motion accommodation. Directional and resultant metrics are computed using mean and peak values over movement cycles. Results show that releasing passive joints consistently reduces interaction loading, and Category 2 achieves the lowest forces and torques with the strongest peak suppression, indicating the best practical compatibility.<\/jats:p>","DOI":"10.3390\/biomimetics11020097","type":"journal-article","created":{"date-parts":[[2026,2,3]],"date-time":"2026-02-03T12:46:11Z","timestamp":1770122771000},"page":"97","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":2,"title":["Experimental Evaluation of Kinematic Compatibility in Three Upper Limb Exoskeleton Configurations Using Interface Force and Torque"],"prefix":"10.3390","volume":"11","author":[{"given":"Hui","family":"Zeng","sequence":"first","affiliation":[{"name":"School of Bailie Mechanical Engineering, Lanzhou City University, No. 572, Anning East Road, Anning District, Lanzhou 730070, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Hao","family":"Liu","sequence":"additional","affiliation":[{"name":"School of Bailie Mechanical Engineering, Lanzhou City University, No. 572, Anning East Road, Anning District, Lanzhou 730070, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Longfei","family":"Fu","sequence":"additional","affiliation":[{"name":"School of Electrical Engineering, Lanzhou Institute of Technology, No. 1942, East Section of Changjiang Avenue, Lanzhou New Area, Lanzhou 730050, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Qiang","family":"Cao","sequence":"additional","affiliation":[{"name":"School of Mechanical Engineering, Shanghai DianJi University, 300 Shuihua Road, Pudong District, Shanghai 201306, China"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2026,2,1]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","unstructured":"Wang, Y., Han, X., Xin, B., and Zhao, P. (2025). Innovations in upper limb rehabilitation robots: A review of mechanisms, optimization, and clinical applications. Robotics, 14.","DOI":"10.3390\/robotics14060081"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"883","DOI":"10.1007\/s11517-023-02974-0","article-title":"Design and analysis of a compatible exoskeleton rehabilitation robot system based on upper limb movement mechanism","volume":"62","author":"Ning","year":"2023","journal-title":"Med. Biol. Eng. Comput."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"104701","DOI":"10.1016\/j.robot.2024.104701","article-title":"Compensation-corrective adaptive control strategy for upper-limb rehabilitation robots","volume":"177","author":"Cai","year":"2024","journal-title":"Robot. Auton. Syst."},{"key":"ref_4","doi-asserted-by":"crossref","unstructured":"Mahfouz, D.M., Shehata, O.M., Morgan, E.I., and Arrichiello, F. (2024). A comprehensive review of control challenges and methods in end-effector upper-limb rehabilitation robots. Robotics, 13.","DOI":"10.3390\/robotics13120181"},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"174","DOI":"10.1016\/j.cogr.2024.09.001","article-title":"Emerging trends in human upper extremity rehabilitation robot","volume":"4","author":"Hasan","year":"2024","journal-title":"Cogn. Robot."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"2337735","DOI":"10.1080\/07853890.2024.2337735","article-title":"Portable robots for upper-limb rehabilitation after stroke: A systematic review and meta-analysis","volume":"56","author":"Tseng","year":"2024","journal-title":"Ann. Med."},{"key":"ref_7","doi-asserted-by":"crossref","unstructured":"Diaz, F.H., Borr\u00e1s Pinilla, C., and Cena, C.E.G. (2025). Exploring robotic technologies for upper limb rehabilitation: Current status and future directions. J. Sens. Actuator Netw., 14.","DOI":"10.3390\/jsan14030048"},{"key":"ref_8","doi-asserted-by":"crossref","unstructured":"Zhang, Y., Li, T., Tao, H., Liu, F., Hu, B., Wu, M., and Yu, H. (2024). Research on adaptive impedance control technology of upper limb rehabilitation robot based on impedance parameter prediction. Front. Bioeng. Biotechnol., 11.","DOI":"10.3389\/fbioe.2023.1332689"},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"4849","DOI":"10.1109\/TMECH.2025.3567128","article-title":"Optimizing design and control methods for using collaborative robots in upper limb rehabilitation","volume":"30","author":"Onfiani","year":"2025","journal-title":"IEEE\/ASME Trans. Mechatron."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"69","DOI":"10.1186\/s10033-024-01056-y","article-title":"Assistive robotics for upper limb physical rehabilitation: A systematic review and future prospects","volume":"37","author":"Guatibonza","year":"2024","journal-title":"Chin. J. Mech. Eng."},{"key":"ref_11","doi-asserted-by":"crossref","unstructured":"Guo, B., Li, Z., Huang, M., Li, X., and Han, J. (2024). Patient\u2019s healthy-limb motion characteristic-based assist-as-needed control strategy for upper-limb rehabilitation robots. Sensors, 24.","DOI":"10.20944\/preprints202401.1235.v1"},{"key":"ref_12","first-page":"303","article-title":"Soft robotics in upper limb neurorehabilitation and assistance: Current clinical evidence and recommendations","volume":"12","author":"Tanczak","year":"2024","journal-title":"Soft Robot."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"164","DOI":"10.1186\/s12984-025-01662-4","article-title":"Upper limb robotic rehabilitation following stroke: A systematic review and meta-analysis investigating efficacy and the influence of device features and program parameters","volume":"22","author":"Boardsworth","year":"2025","journal-title":"J. Neuroeng. Rehabil."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"25476","DOI":"10.1038\/s41598-024-77137-8","article-title":"Upper limb exoskeleton rehabilitation robot inverse kinematics modeling and solution method based on multi-objective optimization","volume":"14","author":"Ning","year":"2024","journal-title":"Sci. Rep."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"035044","DOI":"10.1088\/1361-665X\/ad2b1c","article-title":"Design and feasibility analysis of magnetorheological flexible joint for upper limb rehabilitation","volume":"33","author":"Li","year":"2024","journal-title":"Smart Mater. Struct."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"697","DOI":"10.1109\/TRO.2011.2178151","article-title":"Connecting a human limb to an exoskeleton","volume":"28","author":"Jarrasse","year":"2011","journal-title":"IEEE Trans. Robot. IEEE Trans. Robot."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"1729881417710796","DOI":"10.1177\/1729881417710796","article-title":"A number synthesis method of the self-adapting upper-limb rehabilitation exoskeletons","volume":"14","author":"Li","year":"2017","journal-title":"Int. J. Adv. Robot. Syst."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"432","DOI":"10.1161\/STROKEAHA.122.042022","article-title":"Burden of stroke in Europe: An analysis of the Global Burden of Disease Study findings from 2010 to 2019","volume":"55","author":"Prendes","year":"2024","journal-title":"Stroke A J. Cereb. Circ."},{"key":"ref_19","doi-asserted-by":"crossref","unstructured":"Ito, D., Fukuda, M., Hosoi, Y., Hirose, R., Teramae, T., Kamimoto, T., Yamada, Y., Tsuji, T., Noda, T., and Kawakami, M. (2024). Optimizing shoulder elevation assist rate in exoskeletal rehabilitation based on muscular activity indices: A clinical feasibility study. BMC Neurol., 24.","DOI":"10.1186\/s12883-024-03651-x"},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"1471","DOI":"10.1111\/ans.18475","article-title":"Rehabilitation for total shoulder replacement: An Australian perspective","volume":"93","author":"Mousley","year":"2023","journal-title":"ANZ J. Surg."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"481","DOI":"10.1016\/j.pmr.2023.01.001","article-title":"Muscular retraining and rehabilitation after shoulder muscle tendon transfer","volume":"34","author":"Ahmed","year":"2023","journal-title":"Phys. Med. Rehabil. Clin. N. Am."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"553","DOI":"10.1007\/s13534-023-00324-5","article-title":"Robot-assisted orthopedic surgeries around the shoulder joint: Where we are?","volume":"13","author":"Ryul","year":"2023","journal-title":"Biomed. Eng. Lett."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"e141","DOI":"10.1097\/PHM.0000000000002242","article-title":"Shoulder pain after influenza vaccine administration","volume":"102","author":"Zeldin","year":"2023","journal-title":"Am. J. Phys. Med. Rehabil."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"e49","DOI":"10.1016\/j.apmr.2022.12.142","article-title":"Reliability and validity of the Quick Disabilities of the Arm, Shoulder, and Hand questionnaire in Taiwan","volume":"104","author":"Chao","year":"2023","journal-title":"Arch. Phys. Med. Rehabil."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"pzae029","DOI":"10.1093\/ptj\/pzae029","article-title":"Application of the staged approach for rehabilitation classification systems and associated improvements in patient-reported outcomes following rehabilitation for shoulder pain","volume":"104","author":"Podschun","year":"2024","journal-title":"Phys. Ther."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"408","DOI":"10.1109\/TMECH.2007.901934","article-title":"Upper-limb powered exoskeleton design","volume":"12","author":"Perry","year":"2007","journal-title":"IEEE\/ASME Trans. Mechatron."},{"key":"ref_27","doi-asserted-by":"crossref","unstructured":"Reinkensmeyer, D.J., Zondervan, D.K., Andr\u00e9s, M., and Comellas, M. (2022). Upper-extremity movement training with mechanically assistive devices. Neurorehabilitation Technology, Springer International Publishing.","DOI":"10.1007\/978-3-031-08995-4_28"},{"key":"ref_28","doi-asserted-by":"crossref","unstructured":"Nef, T., Klamroth-Marganska, V., Keller, U., and Riener, R. (2022). Three-dimensional multi-degree-of-freedom arm therapy robot (ARMin). Neurorehabilitation Technology, Springer International Publishing.","DOI":"10.1007\/978-3-031-08995-4_27"},{"key":"ref_29","first-page":"41","article-title":"Comparison between radial pressure wave therapy and stretching on shoulder range of motion of horizontal flexion and internal rotation","volume":"14","author":"Miyauchi","year":"2023","journal-title":"Sci. Res. Phys. Ther."},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"1448","DOI":"10.1016\/j.medengphy.2012.02.003","article-title":"An intrinsically compliant robotic orthosis for treadmill training","volume":"34","author":"Hussain","year":"2012","journal-title":"Med. Eng. Phys."},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"256","DOI":"10.1016\/j.gaitpost.2010.11.016","article-title":"A cable-driven locomotor training system for restoration of gait in human SCI","volume":"33","author":"Wu","year":"2011","journal-title":"Gait Posture"},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"838","DOI":"10.1109\/TRO.2013.2256309","article-title":"Rehabilitation exoskeleton design: Exploring the effect of the anterior lunge degree of freedom","volume":"29","author":"Stegall","year":"2013","journal-title":"IEEE Trans. Robot."},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"490","DOI":"10.1109\/TNSRE.2012.2225073","article-title":"Developing a multi-joint upper limb exoskeleton robot for diagnosis, therapy, and outcome evaluation in neurorehabilitation","volume":"21","author":"Ren","year":"2012","journal-title":"IEEE Trans. Neural Syst. Rehabil. Eng."},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"011016","DOI":"10.1115\/1.4048428","article-title":"A double-layered EL exoskeleton interface with 3-PRR planar parallel mechanism for axis self-alignment","volume":"13","author":"Awad","year":"2020","journal-title":"J. Mech. Robot."},{"key":"ref_35","doi-asserted-by":"crossref","unstructured":"Florian, G., Georgios, N., and Alireza, G. (2016). Compensation or restoration: Closed-loop feedback of movement quality for assisted reach-to-grasp exercises with a multi-joint arm exoskeleton. Front. Neurosci., 10.","DOI":"10.3389\/fnins.2016.00280"},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"2285","DOI":"10.1109\/TMECH.2014.2375272","article-title":"LIMPACT: A hydraulically powered self-aligning upper limb exoskeleton","volume":"20","year":"2015","journal-title":"IEEE\/ASME Trans. Mechatron."},{"key":"ref_37","doi-asserted-by":"crossref","unstructured":"Mishra, S., Narayan, J., Nikum, A.K., and Singh, R. (2022). Design and modeling of a novel exoskeleton suit for load-bearing augmentation. Revolutions in Product Design for Healthcare: Advances in Product Design and Design Methods for Healthcare, Springer.","DOI":"10.1007\/978-981-16-9455-4_4"},{"key":"ref_38","doi-asserted-by":"crossref","first-page":"104146","DOI":"10.1016\/j.mechmachtheory.2020.104146","article-title":"Compatibility evaluation of a 4-DOF ergonomic exoskeleton for upper limb rehabilitation","volume":"156","author":"Li","year":"2021","journal-title":"Mech. Mach. Theory"},{"key":"ref_39","doi-asserted-by":"crossref","unstructured":"Dehez, B., and Sapin, J. (July, January 29). ShouldeRO, an alignment-free two-DOF rehabilitation robot for the shoulder complex. Proceedings of the 2011 IEEE International Conference on Rehabilitation Robotics, Zurich, Switzerland.","DOI":"10.1109\/ICORR.2011.5975339"},{"key":"ref_40","doi-asserted-by":"crossref","first-page":"041008","DOI":"10.1115\/1.4040132","article-title":"Kinematic analysis and design of a novel shoulder exoskeleton using a double parallelogram linkage","volume":"10","author":"Christensen","year":"2018","journal-title":"J. Mech. Robot."},{"key":"ref_41","doi-asserted-by":"crossref","first-page":"031006","DOI":"10.1115\/1.4052446","article-title":"Design of the wearable spatial gravity balance mechanism","volume":"14","author":"Peng","year":"2022","journal-title":"J. Mech. Robot."},{"key":"ref_42","doi-asserted-by":"crossref","first-page":"23","DOI":"10.1007\/s10846-023-01963-7","article-title":"Adaptive gait trajectory and event prediction of lower limb exoskeletons for various terrains using reinforcement learning","volume":"109","author":"Yang","year":"2023","journal-title":"J. Intell. Robot. Syst. Theory Appl."},{"key":"ref_43","doi-asserted-by":"crossref","first-page":"692","DOI":"10.1007\/s41315-024-00345-y","article-title":"Research on compliant human\u2013robot interaction based on admittance control strategy for shoulder rehabilitation exoskeleton with CGH self-alignment function","volume":"8","author":"Shen","year":"2024","journal-title":"Int. J. Intell. Robot. Appl."},{"key":"ref_44","doi-asserted-by":"crossref","first-page":"992","DOI":"10.1007\/s42235-022-00299-6","article-title":"Designing unpowered shoulder complex exoskeleton via contralateral drive for self-rehabilitation of post-stroke hemiparesis","volume":"20","author":"Li","year":"2022","journal-title":"J. Bionic Eng."},{"key":"ref_45","doi-asserted-by":"crossref","unstructured":"Cao, Q., Shan, W., Liu, Y., and Yuan, Y. (2025). Enhancing Human-Robot Compatibility in Shoulder Exoskeletons: Passive Joint Optimization of PPRRRP vs. RRRUP Configurations. Biomimetics, 10.","DOI":"10.3390\/biomimetics10120795"}],"container-title":["Biomimetics"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2313-7673\/11\/2\/97\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,2,4]],"date-time":"2026-02-04T05:13:08Z","timestamp":1770181988000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2313-7673\/11\/2\/97"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,2,1]]},"references-count":45,"journal-issue":{"issue":"2","published-online":{"date-parts":[[2026,2]]}},"alternative-id":["biomimetics11020097"],"URL":"https:\/\/doi.org\/10.3390\/biomimetics11020097","relation":{},"ISSN":["2313-7673"],"issn-type":[{"value":"2313-7673","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,2,1]]}}}