Intergrated Shape Memory Alloys Soft Actuators with Periodic and Inhomogeneous Deformations by Modulating Elastic Tendon Structures

Abstract

The soft actuators similar to the periodic motion of biological organisms are accomplished based on assembling multiple unidirectional memory effect shape memory alloys (SMAs) components or introducing biasing elements, which give rise to the complex structure and difficult control of soft actuators. Herein, inspired by the power‐amplified biological systems, beneficial with the advantages of 3D integrated molding technology, an integrated SMA‐polydimethylsiloxane (PDMS) composite structure (SPCS) is proposed, which can achieve periodic heterogeneous actuation only by controlling the SMA phase transformation and the PDMS strain potential energy distribution states. To test the feasibility of the mechanism, a theoretical model of SPCS deformation is conducted. The results of numerical feasibility analysis show that the factors affecting SPCS deformation mainly involve the excitation current strength of SMA, PDMS structure thickness and its distribution state. The experimental results show that the current intensity mainly affects the deformation rate of SPCS, and the thickness of PDMS is not only the key to realize the periodic deformation of SPCS but also the orderly arrangement of PDMS structure thickness is helpful for SPCS to achieve periodic heterogeneous deformation. These demonstrate that the proposed mechanism can inspire the design of soft actuators, smart wearable equipment, and medical devices.