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1. Numerical Finger Kinematic Models Derived From Virtual Grasping of Various Cylindrical Objects With the Family of Conic Sections

   https://doi.org/10.1115/1.4048257  

   Won, Jong-Seob; Langari, Reza; Robson, Nina (February 2021, Journal of Mechanisms and Robotics)

   null (Ed.)

   Abstract In this study, a numerical framework for joint rotation configuration models of a finger is proposed. The basic idea is to replicate the finger’s geometric posture observed when the human hand grasps a cylindrical object with various cross sections. In the model development, objects with the cross section adopted from the curves of order two (the family of conic sections) are taken into consideration to realize various finger postures. In addition, four different grasp styles, which simulate the individual-specific contact pattern between the surfaces of object and finger, are modeled and applied for the formulation of numerical models. An idea on how to change flexion/extension patterns in the middle of excursion of movement is proposed and discussed. Series of numerical studies have been conducted and analyzed to evaluate the proposed models. From the results, one can see the models’ feasibility and viability as a solution to describing finger’s flexion/extension movements (FEMs) for grasping patterns. 

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2. Flexion and Extension Capable Motor Tendon Actuated Exosuit Glove with Open Palm

   Patterson, G.; Zell, T.; Parker, D.; Grieve, J.; Watson, S.; Vikas, V. (August 2019, Proceedings of the ASME 2019 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference)

   Patients suffering from medical conditions resulting in hand impairment experience difficulty in performing simple daily tasks, like getting dressed or using a pencil, resulting in a poorer quality of life. Rehabilitation attempts to help such individuals regain a sense of control and normalcy. In this context, recent advances in robotics have manifested in multiple designs of hand exoskeletons and exosuit gloves for assistance and rehabilitation. These designs are typically actuated using pneumatic, shape memory alloys and motor-tendon actuators. The proposed Motor Tendon Actuated Exosuit Glove (MTAEG) with an open palm is a soft material glove capable of both flexion and extension of all four fingers of the human hand. Its minimally invasive design maintains an open palm to facilitate haptic and tactile interaction with the environment. The MTAEG achieves flexion-extension motion with joint angles of 45° at the metacarpal joint which is 57% of the desired motion; 90° at the proximal interphalangeal joint which is 100% of the desired motion; and 50° at the distal interphalangeal joint which is 96% of the desired motion. The paper discusses the challenges in achieving the desired motion without the ability to directly model human tendons, and the inability to actuate joints individually. 

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3. STAR–2: A Soft Twisted-string-actuated Anthropomorphic Robotic Gripper: Design, Fabrication, and Preliminary Testing

   https://doi.org/10.1109/AIM46323.2023.10196149  

   Baker, Aaron; Foy, Claire; Swanbeck, Steven; Konda, Revanth; Zhang, Jun (June 2023, IEEE)

   While numerous studies have been conducted, developing a compliant robotic gripper capable of replicating human hand grasping and manipulation capabilities is still challenging. This paper presents the design, fabrication, and preliminary testing of an anthropomorphic soft robotic gripper driven by twisted string actuators (TSAs). Termed as STAR–2, it is a second generation TSA-driven soft gripper from the Smart Robotics Laboratory at the University of Nevada, Reno. The novel design facilitated a monolithic structure comprising of a 3-degrees-of-freedom (DOF) thumb and four fingers each with 2-DOFs. On account of using tendon-based actuation and the large footprint required for the thumb, the design employed meticulously planned tendon routing within the monolithic structure. Preliminary results showed STAR–2’s enhanced ability to demonstrate grasp taxonomies and dexterity over STAR–1. 

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4. Transcriptome profiling of tendon fibroblasts at the onset of embryonic muscle contraction reveals novel force-responsive genes

   https://doi.org/10.7554/eLife.105802  

   Nayak, Pavan K; Subramanian, Arul; Schilling, Thomas F (March 2025, eLife)

   Mechanical forces play a critical role in tendon development and function, influencing cell behavior through mechanotransduction signaling pathways and subsequent extracellular matrix (ECM) remodeling. Here, we investigate the molecular mechanisms by which tenocytes in developing zebrafish embryos respond to muscle contraction forces during the onset of swimming and cranial muscle activity. Using genome-wide bulk RNA sequencing of FAC-sorted tenocytes we identify novel tenocyte markers and genes involved in tendon mechanotransduction. Embryonic tendons show dramatic changes in expression ofmatrix remodeling associated 5b(mxra5b),matrilin 1(matn1), and the transcription factorkruppel-like factor 2a(klf2a), as muscles start to contract. Using embryos paralyzed either by loss of muscle contractility or neuromuscular stimulation we confirm that muscle contractile forces influence the spatial and temporal expression patterns of all three genes. Quantification of these gene expression changes across tenocytes at multiple tendon entheses and myotendinous junctions reveals that their responses depend on force intensity, duration, and tissue stiffness. These force-dependent feedback mechanisms in tendons, particularly in the ECM, have important implications for improved treatments of tendon injuries and atrophy. 

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5. Design and Control of Foam Hands for Dexterous Manipulation

   https://doi.org/10.1142/S0219843619500336  

   Bauer, Dominik; Bauer, Cornelia; King, Jonathan P.; Moro, Daniele; Chang, Kai-Hung; Coros, Stelian; Pollard, Nancy (February 2020, International Journal of Humanoid Robotics)

   null (Ed.)

   There has been great progress in soft robot design, manufacture, and control in recent years, and soft robots are a tool of choice for safe and robust handling of objects in conditions of uncertainty. Still, dexterous in-hand manipulation using soft robots remains a challenge. This paper introduces foam robot hands actuated by tendons sewn through a fabric glove. The flexibility of tendon actuation allows for high competence in utilizing deformation for robust in-hand manipulation. We discuss manufacturing, control, and design optimization for foam robots and demonstrate robust grasping and in-hand manipulation on a variety of different physical hand prototypes. 

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