Design of a variable-stiffness robotic hand using pneumatic soft rubber actuators

Nagase, Jun Ya; Wakimoto, Shuichi; Satoh, Toshiyuki; Saga, Norihiko; Suzumori, Koichi

doi:10.1088/0964-1726/20/10/105015

Cited by 69 publications

(28 citation statements)

References 20 publications

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“…Tendon‐driven is also able to achieve variable stiffness through antagonistic configurations . However, since little work has been done with soft materials, we focus on the others technologies listed above …”

Section: Gripping By Controlled Stiffnessmentioning

confidence: 99%

Soft Robotic Grippers

et al. 2018

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Advances in soft robotics, materials science, and stretchable electronics have enabled rapid progress in soft grippers. Here, a critical overview of soft robotic grippers is presented, covering different material sets, physical principles, and device architectures. Soft gripping can be categorized into three technologies, enabling grasping by: a) actuation, b) controlled stiffness, and c) controlled adhesion. A comprehensive review of each type is presented. Compared to rigid grippers, end-effectors fabricated from flexible and soft components can often grasp or manipulate a larger variety of objects. Such grippers are an example of morphological computation, where control complexity is greatly reduced by material softness and mechanical compliance. Advanced materials and soft components, in particular silicone elastomers, shape memory materials, and active polymers and gels, are increasingly investigated for the design of lighter, simpler, and more universal grippers, using the inherent functionality of the materials. Embedding stretchable distributed sensors in or on soft grippers greatly enhances the ways in which the grippers interact with objects. Challenges for soft grippers include miniaturization, robustness, speed, integration of sensing, and control. Improved materials, processing methods, and sensing play an important role in future research.

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Section: Gripping By Controlled Stiffnessmentioning

confidence: 99%

Soft Robotic Grippers

et al. 2018

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“…Theoretical and FEM studies done by [8] and [11] have proven that contraction ratio is 0 % when the fiber angle at both sides is modeled to be 54.8°. The actuator braided with fiber angle of 54.8° around the chamber will only show changes in stiffness but not in expansion nor contraction.…”

Section: The Proposed Design and Its Working Principlementioning

confidence: 98%

3-D finite-element analysis of fiber-reinforced soft bending actuator for finger flexion

Nordin

Razif

Faudzi

et al. 2013

2013 IEEE/ASME International Conference on Advanced Intelligent Mechatronics

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Towards the development of a safe, small, lightweight and human-friendly finger exoskeleton, device made from high elasticity material driven by pneumatic source; or simply known as soft actuator is currently being paid to attention. The study is to determine the optimum fiber reinforced elastic soft actuator model to be employed in an exoskeleton for finger rehabilitation. Bending motion anticipated from a 3-D finite element actuator model is verified in the nonlinear finite element software, MARCTM. The effectiveness of the proposed model is discussed based on the displacement data obtained from the large strain finite element analysis. Specific geometric properties, material properties, contact and boundary conditions related to the real experimental testing were applied to the analysis. Based on the results, the proposed model shows a good presentation of bending motion at applied pressure of 150 kPa. The behavior of bending motion which is greatly influenced by the angle of the fiber reinforced to the actuator is also discussed.978-1-4673-5320-5/13/$31.00 ©2013 IEEE

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“…This feature enables us to grab lightweight objects avoiding force peak and uncertain impulse to ensure safe interaction and hold heavier objects effectively and reliably. It is also desirable that the gripper can move flexibly and adapt the complex environments at low stiffness and increase stiffness to apply force or lift heavy objects when needed, like human hands, such as bidirectional antagonistic variable stiffness (BAVS) joint of the deutsches zentrum für Luft-und raumfahrt (DLR) hand, 37,38 the variable stiffness device made by silicone rubber, 39 and the variable stiffness mechanism using two motors. 40 Stiffness represents a material or structure to resist elastic deformation when subjected to external forces.…”

Section: Variable Stiffness Performancementioning

confidence: 99%

A novel design of shape-memory alloy-based soft robotic gripper with variable stiffness

Liu

Hao

Zhang

et al. 2020

International Journal of Advanced Robotic Systems

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Soft robotic grippers with compliance have great superiority in grabbing objects with irregular shape or fragility compared with traditional rigid grippers. The main limitations of such systems are small grasping force resulted from properties of soft actuators and lacking variable stiffness of soft robotic grippers, which prevent them from a larger wide range of applications. This article proposes a shape-memory alloy (SMA)-based soft gripper with variable stiffness composed of three robotic fingers for grasping compliantly at low stiffness and holding robustly at high stiffness. Each robotic finger mainly consisted of stiff parts and two variable stiffness joints is installed on the base with a specific angle. The paraffin as a variable stiffness material in the joint can be heated or cooled to change the stiffness of the robotic fingers. Results of experiments have shown that a single robotic finger can approximately achieve 18-fold stiffness enhancement. Each finger with two joints can actively achieve multiple postures by both changing the corresponding stiffness of joints and actuating the SMA wire. Based on these principles, the gripper can be applied to grasp objects with different shapes and a large range of weights, and the maximum grasping force of the gripper is increased to about 10 times using the variable stiffness joints. The final experiment is conducted to validate variable stiffness of the proposed soft grippers grasping an object.

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Design of a variable-stiffness robotic hand using pneumatic soft rubber actuators

Cited by 69 publications

References 20 publications

Soft Robotic Grippers

Soft Robotic Grippers

3-D finite-element analysis of fiber-reinforced soft bending actuator for finger flexion

A novel design of shape-memory alloy-based soft robotic gripper with variable stiffness

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