Twisted string actuation with sliding surfaces

Palli, Gianluca; Hosseini, Mohssen; Melchiorri, Claudio

doi:10.1109/iros.2016.7759064

Cited by 11 publications

(9 citation statements)

References 11 publications

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“…This was done to prevent any twisting of the strings within the silicone hand itself. As suggested by previous studies [47], [48], early experiments revealed that friction between the twisted strings and the inside of the hand would prevent the strings from fully untwisting. This phenomenon resulted in significant creep in the actuation of the hand between cycles.…”

Section: A Designmentioning

confidence: 67%

“…This problem persisted even when the PTFE tubes were introduced, but was greatly reduced when the twisted regions were moved completely out of the hand. The bending of the twisted regions while inside the hand would have also made them more difficult to model [47], [48].…”

Section: A Designmentioning

confidence: 99%

“…The nonlinearities consisted of hysteresis with lonely stroke behavior and also a small amount of creep. These nonlinearities could be due to multiple reasons including (1) the inherent material properties of the silicone [25] and (2) the frictional force between the strings and the PTFE tubes [47], [48]. Readers are encouraged to read [48], where the force outputs of a TSA are modelled while sliding on a surface with friction.…”

Section: A Usage Of Soft Materialsmentioning

confidence: 99%

“…These nonlinearities could be due to multiple reasons including (1) the inherent material properties of the silicone [25] and (2) the frictional force between the strings and the PTFE tubes [47], [48]. Readers are encouraged to read [48], where the force outputs of a TSA are modelled while sliding on a surface with friction. Although all the fingers exhibited acceptable consistency in their respective motor angle-fingertip angle correlations under different orientations, the presence of the aforementioned nonlinearities could complicate the physics-based modeling process.…”

Section: A Usage Of Soft Materialsmentioning

confidence: 99%

See 3 more Smart Citations

Anthropomorphic Twisted String-Actuated Soft Robotic Gripper with Tendon-Based Stiffening

Bombara¹,

Konda²,

Swanbeck³

et al. 2022

Preprint

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Realizing high-performance soft robotic grippers is challenging because of the inherent limitations of the soft actuators and artificial muscles that drive them. Although existing soft robotic grippers exhibit acceptable performance, their design and fabrication are still an open problem. This paper explores twisted string actuators (TSAs) to drive a soft robotic gripper. TSAs have been widely used in numerous robotic applications, but their inclusion in soft robots has been limited. The proposed design of the gripper was inspired by the human hand, with four fingers and a thumb. Tunable stiffness was implemented in the fingers by using antagonistic TSAs. The fingers' bending angles, actuation speed, blocked force output, and stiffness tuning were experimentally characterized. The gripper was able to achieve a score of 6 on the Kapandji test, and was also to achieve 31 of the 33 grasps of the Feix GRASP taxonomy. A comparison study revealed that the proposed gripper exhibited equivalent or superior performance compared to other similar grippers.

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Section: A Designmentioning

confidence: 67%

Section: A Designmentioning

confidence: 99%

Section: A Usage Of Soft Materialsmentioning

confidence: 99%

Section: A Usage Of Soft Materialsmentioning

confidence: 99%

See 2 more Smart Citations

Anthropomorphic Twisted String-Actuated Soft Robotic Gripper with Tendon-Based Stiffening

Bombara¹,

Konda²,

Swanbeck³

et al. 2022

Preprint

View full text Add to dashboard Cite

show abstract

“…The literature survey indicates some similar approaches that allow wires to contact and/or slide against one another. For instance the Twisted String Actuator generates a compression force by twisting two or more synthetic fiber strings [7] [8]. Nakamoto et al designed a 7-DoF wire-driven humanoid arm, and the wires for distal joints were squeezed at a proximal link in order to locate them close to the endorotation axis in the arm [9].…”

Section: Proposal Of Bundled Wire Drivementioning

confidence: 99%

Bundled Wire Drive: Proposal and Feasibility Study of a Novel Tendon-Driven Mechanism Using Synthetic Fiber Ropes

Endo

Wakabayashi

Nabae

et al. 2019

IEEE Robot. Autom. Lett.

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This paper proposes a new wire-driven mechanism in order to relay many ropes very simply and compactly. Ropes pass through in a joint while bundled. Synthetic fiber rope can slide and twist, exploiting its low friction coefficient. In order to use this mechanism, it is necessary to investigate the influence of sliding on tension transmission efficiency and rope strength. The results of this study reveal that it is feasible for a robot arm using this mechanism to have more than 15 joints. Sliding has little influence on rope strength. The feasibility of this system was studied through hardware experiments and its mechanical performance was evaluated by constructing a horizontally extendable manipulator with three degrees of freedom.

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Overtwisting and Coiling Highly Enhance Strain Generation of Twisted String Actuators

Konda,

Bombara,

Zhang

2023

Soft Robotics

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Twisted string actuation with sliding surfaces

Cited by 11 publications

References 11 publications

Anthropomorphic Twisted String-Actuated Soft Robotic Gripper with Tendon-Based Stiffening

Anthropomorphic Twisted String-Actuated Soft Robotic Gripper with Tendon-Based Stiffening

Bundled Wire Drive: Proposal and Feasibility Study of a Novel Tendon-Driven Mechanism Using Synthetic Fiber Ropes

Overtwisting and Coiling Highly Enhance Strain Generation of Twisted String Actuators

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