THERMO-MECHANICAL BEHAVIOUR OF SMA WIRE EMBEDDED PDMS ACTUATOR TOWARDS SOFT ROBOTICS APPLICATIONS

M. Muralidharan,∗ K. Aishwarya,∗∗ R. Mithun,∗∗∗ and I.A. Palani∗

Keywords

Soft actuator, shape memory alloy, PDMS

Abstract

The actuation behaviour of the shape memory alloy (SMA) wire- embedded polydimethylsiloxane (PDMS) based soft robotic actuator has been investigated. The fabricated soft robotic actuator has been actuated through resistive heating under varying input current. The soft actuator has showed a maximum displacement of 7.5 mm at 2 A input current. To widen the displacement capabilities of the soft actuator, the SMA wire was pre-strained in the range 1%–8% before being embedded in the soft matrix. The pre- straining of the wire has improved the actuation behaviour and notably 8% pre-strained SMA wire-embedded PDMS actuator has showed a maximum displacement of 21 mm. Life cycle analysis has been carried out and the soft actuator has maintained an average displacement of 6 mm even after 200 cycles. The thermal behaviour of the proposed actuator has been studied using COMSOL Multiphysics software. The proposed actuator can be used in soft robotic devices such as soft gripper, soft robotic manipulator, soft tentacles in biomimetic devices such as jellyfish, starfish, etc.

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