Development of a Miniature Robot Finger with a Variable Stiffness Mechanism Using Shape Memory Alloy

2004 ◽  
Vol 2004 (0) ◽  
pp. 108 ◽  
Author(s):  
T Hino ◽  
T Maeno
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Variable Stiffness ◽  
Miniature Robot

A shape memory alloy–actuated soft crawling robot based on adaptive differential friction and enhanced antagonistic configuration

2020 ◽  
Vol 31 (16) ◽  
pp. 1920-1934 ◽  
Author(s):  
Chen Liang ◽  
Yongquan Wang ◽  
Tao Yao ◽  
Botao Zhu
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Stride Length ◽  
Parametric Design ◽  
Thermoplastic Polyurethane ◽  
Interaction Mechanism ◽  
Experimental Tests ◽  
The Body ◽  
3D Printed ◽  
Miniature Robot

This article presents a soft crawling robot prototype with a simple architecture inspired by inchworms. The robot functionally integrates the torso (body) and feet in a monolithic curved structure that only needs a single shape memory alloy coil and differential friction to actuate it. A novel foot configuration is proposed, which makes the two feet, with an anti-symmetrical friction layout, can be alternately anchored, to match the contraction–recovery sequence of the body adaptively. Based on the antagonistic configuration between the shape memory alloy actuator and the elastic body, a vertically auxiliary spring was adopted to enhance the interaction mechanism. Force and kinematic analysis was undertaken, focusing on the parametric design of the special foot configuration. A miniature robot prototype was then 3D-printed (54 mm in length and 9.77 g in weight), using tailored thermoplastic polyurethane elastomer as the body material. A series of experimental tests and evaluations were carried out to assess its performance under different conditions. The results demonstrated that under appropriate actuation conditions, the compact robot prototype could accomplish a relative speed of 0.024 BL/s (with a stride length equivalent to 27% of its body length) and bear a load over five times to its own weight.

scholarly journals Shape Memory Alloy-Based Soft Finger with Changeable Bending Length Using Targeted Variable Stiffness

Soft Robotics ◽  
2020 ◽  
Vol 7 (3) ◽  
pp. 283-291 ◽  
Author(s):  
Wei Wang ◽  
Chak Yuk Yu ◽  
Pablo Antonio Abrego Serrano ◽  
Sung-Hoon Ahn
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Variable Stiffness ◽  
Bending Length ◽  
Soft Finger

A novel variable-stiffness flexible manipulator actuated by shape memory alloy for minimally invasive surgery

2018 ◽  
Vol 232 (11) ◽  
pp. 1098-1110 ◽  
Author(s):  
Yanfei Cao ◽  
Feng Ju ◽  
Lei Zhang ◽  
Dongming Bai ◽  
Fei Qi ◽  
...  
Keyword(s):  
Minimally Invasive Surgery ◽  
Shape Memory Alloy ◽  
Minimally Invasive ◽  
Shape Memory ◽  
Invasive Surgery ◽  
Variable Stiffness ◽  
Flexible Manipulator ◽  
Phase Transformation Temperature ◽  
Shape Memory Alloy Wire ◽  
Alloy Wire

This article presents a novel variable-stiffness flexible manipulator for minimally invasive surgery. Each module of the proposed manipulator contains a variable-stiffness mechanism actuated by proactive deformation of shape memory alloy. Due to low driving current, apparent mechanical deformation, suitable phase transformation temperature and biocompatibility of shape memory alloy wire actuation, it is well suited for the manipulator applied in minimally invasive surgery, where variable stiffness is urgently required. In this article, the conceptual design, elastic modulus model, thermo-electric model, stiffness controlling method and finite element method simulation for a single module of the proposed variable-stiffness flexible manipulator are presented. Moreover, the memory shape setting experiment of shape memory alloy wire and fabrication of the single module are carried out. Finally, stiffness characterizations of the mechanism and the single module are studied separately, theoretically and experimentally.

Synergistically configured shape memory alloy for variable stiffness translational actuation

2019 ◽  
Vol 30 (6) ◽  
pp. 844-854 ◽  
Author(s):  
D Nalini ◽  
K Dhanalakshmi
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Variable Stiffness ◽  
Large Displacement ◽  
Linear Actuator ◽  
Shape Memory Alloy Wire ◽  
Alloy Wire ◽  
Active Compliance ◽  
Wide Range ◽  
Stiffness Profile

The structural composition of two elastic elements, shape memory alloy wire (active actuating element) and spring (the passive bias), offers variable stiffness actuation. Based on this principle, a variable stiffness linear actuator is conceptually designed and developed. It is electromechanical by nature, that is, it is electrically activated and creates translational/linear motion. The variable stiffness linear actuator engages shape memory alloy wire(s) along with a passive compression spring to work synergistically. The biasing element offers recovery force to the shape memory alloy wire as well as compliance to the whole structure. The synergistic configuration exhibits an aiding force, thereby allowing an actuation with large displacement and a wide range of stiffness. The actuator mechanism is implemented through parallel action and further proposes two different modes of operation: pull mode (i.e. the disc moving along a fixed shaft) and push mode (i.e. linear reciprocating motion of the pushrod). The shape memory alloy configured actuator mechanism is analysed theoretically; the working model of the variable stiffness linear actuator is developed and investigated experimentally. The results apprise that the variable stiffness linear actuator is capable of offering large displacement and in reproducing the stiffness profile for active compliance control applications.

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