Date of Award

Spring 1-1-2018

Document Type

Thesis

Degree Name

Master of Science (MS)

First Advisor

Jianliang Xiao

Second Advisor

Yifu Ding

Third Advisor

Mark Rentschler

Abstract

Soft robotics are most inspired from animals harnessing soft structures to move on ground or even harsh topological surface. Soft materials are the primary composition of soft robotics. Although they are not as durable and strong as ceramics and metals, soft materials stand out for their reversibility of deformation, response to stimuli and bio-compatibility. In this dissertation, liquid crystalline elastomer(LCE) combined with patterned flexible electronics and liquid metal have been used as soft robotics that simulating different kinds of worm-like movement. Besides, the impressive bendability of LCE finds itself a lot of potential in nature-camouflage area.

First of all, the conception of soft robotics was deeply dug out through references about smart materials, for example, shape memory alloy(SMA), shape memory polymer(SMP), liquid crystalline elastomer(LCE) and etc. In this dissertation, LCE, as an advanced smart material, is used to fabricate soft robots, simulating inchworm movement. Another key point is the designation of actuator, in the research, flexible electronics were integrated onto LCE strip, when voltage was applied, the electronics increased temperature of specific part on one side of strip. Temperature difference between top and bottom surface induced LCE bending to approach anticipated location. Several cycles of inchworm movement were achieved, change in actuation sequence induces an inverse movement direction.

Secondly, an improvement was carried out for crawling robots with combination of liquid metal(LM). Different from flexible electronics which are actually solid, “liquid electronics” suits more in the term “flexible”. Liquid metal was introduced into the research due to elevated requirement of bending curvature for its freely and reversibly transition between solid and liquid. New attachment approach was carried out using passive PDMS layer embedding to solidify contact between liquid metal and LCE. As consequence, the soft robotics could grasp a stick and move itself towards bi-direction. Repeatability test was conducted for the composite bending, twisting and shrinking.

Last but not the least, the LCE/LM system patterned in different shape could easily camouflage itself as black agaric, seaweed and origami pentagram, in another word, the potential application in camouflage of this structure was developed. In specific parts of passive eco-flex layer, LCE segments were embedded and connected by liquid metal channels. For example, to simulate black agaric, four or five spots of the system were expected to bend, when external input was applied, LM in these areas generate and conduct heat around causing bending and maintaining the system at a specific shape, also, black paints were cast onto composite in advance. Repeatability test was conducted and reported.

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