{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,7,30]],"date-time":"2026-07-30T10:31:38Z","timestamp":1785407498900,"version":"3.56.0"},"reference-count":22,"publisher":"MDPI AG","issue":"5","license":[{"start":{"date-parts":[[2026,5,3]],"date-time":"2026-05-03T00:00:00Z","timestamp":1777766400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Postdoctoral Fellowship Program of the China Postdoctoral Science Foundation","award":["GZC20231284"],"award-info":[{"award-number":["GZC20231284"]}]},{"DOI":"10.13039\/501100002858","name":"China Postdoctoral Science Foundation","doi-asserted-by":"crossref","award":["2024M751643"],"award-info":[{"award-number":["2024M751643"]}],"id":[{"id":"10.13039\/501100002858","id-type":"DOI","asserted-by":"crossref"}]},{"award":["2024M751643"],"award-info":[{"award-number":["2024M751643"]}],"id":[{"id":"https:\/\/ror.org\/0426zh255","id-type":"ROR","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Biomimetics"],"abstract":"<jats:p>Soft robotic hands are well suited for handling fragile and geometrically diverse objects, yet many existing designs still rely on fixed finger layouts, which limits grasping adaptability when object size varies substantially. To address this issue, this study proposes a four-finger pneumatic soft robotic hand with a synchronous variable-stroke base mechanism. The design combines a rigid reconfigurable base with compliant soft fingers, allowing the radial positions of the fingers to be adjusted before grasping. A system-level kinematic model is established to describe the relationship between base stroke, finger bending, and the reachable workspace of the hand. A prototype is fabricated, and comparative grasping experiments are conducted under fixed-stroke and variable-stroke configurations using objects with different grasping cross-sections. The results show that the proposed mechanism achieves stable geometric reconfiguration and improves grasping performance when the initial finger spacing is matched to the object size. In particular, the variable-stroke configuration provides better grasp stability and a wider usable grasping range than the fixed-stroke configuration. These findings indicate that geometric reconfiguration at the hand level is an effective way to enhance the adaptability of multi-finger soft robotic hands.<\/jats:p>","DOI":"10.3390\/biomimetics11050318","type":"journal-article","created":{"date-parts":[[2026,5,4]],"date-time":"2026-05-04T01:12:09Z","timestamp":1777857129000},"page":"318","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["A Synchronous Variable-Stroke Mechanism for Workspace Enhancement of a Four-Finger Soft Robotic Hand"],"prefix":"10.3390","volume":"11","author":[{"ORCID":"https:\/\/orcid.org\/0009-0009-5028-9424","authenticated-orcid":false,"given":"Hui","family":"Chen","sequence":"first","affiliation":[{"name":"Department of Mechanical Engineering, Faculty of Engineering, Universiti Malaya, Kuala Lumpur 50603, Malaysia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-0531-014X","authenticated-orcid":false,"given":"Zhenya","family":"Wang","sequence":"additional","affiliation":[{"name":"Department of Mechanical Engineering, Tsinghua University, Beijing 100084, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Shikai","family":"Zhang","sequence":"additional","affiliation":[{"name":"Department of Mechanical Engineering, Faculty of Engineering, Universiti Malaya, Kuala Lumpur 50603, Malaysia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-7183-7794","authenticated-orcid":false,"given":"Ligang","family":"Yao","sequence":"additional","affiliation":[{"name":"School of Mechanical Engineering and Automation, Fuzhou University, Fuzhou 350108, China"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2026,5,3]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","unstructured":"Chi, C., Sun, X., Xue, N., Li, T., and Liu, C. (2018). Recent Progress in Technologies for Tactile Sensors. Sensors, 18.","DOI":"10.3390\/s18040948"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"102893","DOI":"10.1016\/j.rcim.2024.102893","article-title":"Design Synthesis, Modeling, Control Strategies, and Fabrication Methods of Compliant Grippers for Micromanipulation and Micromanipulator: A Comprehensive Review","volume":"92","author":"Le","year":"2025","journal-title":"Robot. Comput.-Integr. Manuf."},{"key":"ref_3","doi-asserted-by":"crossref","unstructured":"Li, X., Chen, W., Li, X., Hou, X., Zhao, Q., Meng, Y., and Tian, Y. (2023). An Underactuated Adaptive Microspines Gripper for Rough Wall. Biomimetics, 8.","DOI":"10.3390\/biomimetics8010039"},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"297","DOI":"10.1146\/annurev-control-100819-063206","article-title":"Recent Advances in Robot Learning from Demonstration","volume":"3","author":"Ravichandar","year":"2020","journal-title":"Annu. Rev. Control Robot. Auton. Syst."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"1707035","DOI":"10.1002\/adma.201707035","article-title":"Soft Robotic Grippers","volume":"30","author":"Shintake","year":"2018","journal-title":"Adv. Mater."},{"key":"ref_6","doi-asserted-by":"crossref","unstructured":"Wu, C., Liu, H., Lin, S., Li, Y., and Chen, Y. (2023). Investigation of Fluidic Universal Gripper for Delicate Object Manipulation. Biomimetics, 8.","DOI":"10.3390\/biomimetics8020209"},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"107094","DOI":"10.1016\/j.ijmecsci.2022.107094","article-title":"Soft Robotic Surface Enhances the Grasping Adaptability and Reliability of Pneumatic Grippers","volume":"219","author":"Xiao","year":"2022","journal-title":"Int. J. Mech. Sci."},{"key":"ref_8","doi-asserted-by":"crossref","unstructured":"Yumbla, F., Quinones Yumbla, E., Mendoza, E., Lara, C., Pagalo, J., Ter\u00e1n, E., Algabri, R., Doh, M., Luong, T., and Moon, H. (2025). An Open-Source 3D Printed Three-Fingered Robotic Gripper for Adaptable and Effective Grasping. Biomimetics, 10.","DOI":"10.3390\/biomimetics10010026"},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"2163","DOI":"10.1002\/adfm.201303288","article-title":"Pneumatic Networks for Soft Robotics That Actuate Rapidly","volume":"24","author":"Mosadegh","year":"2014","journal-title":"Adv. Funct. Mater."},{"key":"ref_10","doi-asserted-by":"crossref","unstructured":"Galloway, K.C., Polygerinos, P., Walsh, C.J., and Wood, R.J. (2013). Mechanically Programmable Bend Radius for Fiber-Reinforced Soft Actuators. Proceedings of the 2013 16th International Conference on Advanced Robotics (ICAR), IEEE.","DOI":"10.1109\/ICAR.2013.6766586"},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"507","DOI":"10.1089\/soro.2018.0112","article-title":"A Fully Multi-Material Three-Dimensional Printed Soft Gripper with Variable Stiffness for Robust Grasping","volume":"6","author":"Zhu","year":"2019","journal-title":"Soft Robot."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"767","DOI":"10.1039\/D5LP00022J","article-title":"Multifunctional Soft Actuator Hybrids: A Review","volume":"3","author":"Lee","year":"2025","journal-title":"RSC Appl. Polym."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"161","DOI":"10.1177\/0278364915592961","article-title":"A Novel Type of Compliant and Underactuated Robotic Hand for Dexterous Grasping","volume":"35","author":"Deimel","year":"2016","journal-title":"Int. J. Robot. Res."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"267","DOI":"10.1016\/j.robot.2017.11.005","article-title":"A Novel Underactuated Multi-Fingered Soft Robotic Hand for Prosthetic Application","volume":"100","author":"Devi","year":"2018","journal-title":"Robot. Auton. Syst."},{"key":"ref_15","doi-asserted-by":"crossref","unstructured":"Sun, J., King, J.P., and Pollard, N.S. (2021). Characterizing Continuous Manipulation Families for Dexterous Soft Robot Hands. Front. Robot. AI, 8.","DOI":"10.3389\/frobt.2021.645290"},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"115380","DOI":"10.1016\/j.sna.2024.115380","article-title":"Soft Robotic Grippers: A Review on Technologies, Materials, and Applications","volume":"372","author":"AboZaid","year":"2024","journal-title":"Sens. Actuators A Phys."},{"key":"ref_17","first-page":"146","article-title":"A Two-Finger Soft-Robotic Gripper with Enveloping and Pinching Grasping Modes","volume":"26","author":"Liu","year":"2020","journal-title":"IEEE\/ASME Trans. Mechatron."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"011001","DOI":"10.1088\/1748-3190\/ad0b8c","article-title":"Variable Stiffness Soft Robotic Gripper: Design, Development, and Prospects","volume":"19","author":"Shan","year":"2024","journal-title":"Bioinspir. Biomim."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"708","DOI":"10.1109\/TIE.2023.3243294","article-title":"MCSG: A Morphology Configurable Soft Gripper With Self-Adaption Modular Composite Finger","volume":"71","author":"Huang","year":"2024","journal-title":"IEEE Trans. Ind. Electron."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"103456","DOI":"10.1016\/j.rineng.2024.103456","article-title":"Performance Optimizing of Pneumatic Soft Robotic Hands Using Wave-Shaped Contour Actuator","volume":"25","author":"Chen","year":"2025","journal-title":"Results Eng."},{"key":"ref_21","doi-asserted-by":"crossref","unstructured":"Tawk, C., Gao, Y., Mutlu, R., and Alici, G. (2019). Fully 3D Printed Monolithic Soft Gripper with High Conformal Grasping Capability. Proceedings of the 2019 IEEE\/ASME International Conference on Advanced Intelligent Mechatronics (AIM), IEEE.","DOI":"10.1109\/AIM.2019.8868668"},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"7706","DOI":"10.1109\/LRA.2021.3098803","article-title":"A Soft Robotic Gripper With an Active Palm and Reconfigurable Fingers for Fully Dexterous In-Hand Manipulation","volume":"6","author":"Pagoli","year":"2021","journal-title":"IEEE Robot. Autom. Lett."}],"container-title":["Biomimetics"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2313-7673\/11\/5\/318\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,5,16]],"date-time":"2026-05-16T04:17:03Z","timestamp":1778905023000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2313-7673\/11\/5\/318"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,5,3]]},"references-count":22,"journal-issue":{"issue":"5","published-online":{"date-parts":[[2026,5]]}},"alternative-id":["biomimetics11050318"],"URL":"https:\/\/doi.org\/10.3390\/biomimetics11050318","relation":{},"ISSN":["2313-7673"],"issn-type":[{"value":"2313-7673","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,5,3]]}}}