A miniaturized soft actuator based on liquid crystal elastomer with temperature-compensated self-sensing capability
Journal
Sensors and Actuators A: Physical
Journal Volume
370
Date Issued
2024-05-01
Author(s)
Abstract
This work presents a miniaturized, electrothermally driven soft actuator that is capable of generating large forces and deformations but also possesses temperature-compensated self-sensing capability. The proposed device comprises an active liquid crystal elastomer (LCE) layer and a conductive composite layer (CCL), and it can easily be realized by simple micromachining techniques with a novel vacuum filtration process. The CCL, consisting of carbon nanotubes (CNTs) and graphite microparticles, functions not only as an electrothermal heater for LCE actuation but also as a piezoresistive sensing material for strain detection. By optimizing the weight percentages of conductive particles, the temperature dependence of the piezoresistive effect of the CCL was minimized, and therefore accurate sensing of LCE deformation can be carried out while actuating LCE electrothermally. A miniaturized two-finger gripper was also implemented by assembling two identical actuators. The gripper was capable of grasping and lifting heavy objects. The payload-to-weight ratio is more than 100 thanks to the phase transition phenomenon of LCE for generating large deformation, while the required actuation voltage is relatively low (i.e., 12 V). In addition, it was also demonstrated to utilize the gripper for measuring the weight of a grasped object with the proposed self-sensing mechanism.
Subjects
Liquid crystal elastomers | Miniaturized soft robots | Self-sensing actuators | Temperature-compensated strain sensing | Vacuum filtration process
Type
journal article