An Underwater Bionic Snake Soft Robot with Tunable Deformation and Motion Based on Composite Materials

Abstract

in underwater object manipulation and marine environment monitoring. Aquatic organisms and amphibians in nature provide great inspiration for the design and manufacture of novel underwater soft robots, which has attracted increased attention from the research community. [9][10][11][12][13] However, the controllability of the driving force still faces great challenges. Existing driving methods mainly include optical drive, [14][15][16][17] magnetic drive, [18,19] and electric drive. [20,21] Among them, optical drive has the highest controllability and tunability, so it is widely used to drive bionic soft robots in underwater operations. In addition, the use of soft smart materials increases the flexibility of bionic robots, reducing the need for heavy, and traditional rigid materials and sensing and actuation components. Most light-driven soft robots are made of liquid crystals [22][23][24][25][26][27] and hydrogels [19] that can undergo various deformations. Mechanical swing is important for converting input energy into continuous motion. Wang et al. reported a light-driven swing actuator composed of polyimide (Kapton) and azobenzene containing liquid crystal polymers. [28] The photoactive bilayer films were prepared with benzene-carboxylic acid containing monomer (M 6 BCOOH) and azobenzene-containing monomer (M 6 ABOC 2 ). When exposed to ultraviolet light, the double-layer film bends. The high modulus of the Kapton layer gives the film great resistance, so the film quickly returns to its resting position after UV light is removed. The double-layer strip exhibits mechanical swing behavior under continuous UV irradiation. Ma et al. also made a light-driven swimmer based on the above double-layer structure. [29] The swimmer bends quickly under UV light and recovers immediately after removing the light. When placed on a liquid surface, swimmers beat the liquid rhythmically, constantly propelling themselves forward.Snake is a kind of amphibian. Despite its simple body structure, it can realize a variety of locomotion forms, such as concertina locomotion and serpentine locomotion, to adapt to the changeable environment. So far, many researchers have studied the movement of snakes. For example, Yang et al. reported a snake-like biomimetic soft robot synthesized by three layers of graphene oxide (GO) and polydopamine. [13,[30][31][32][33] The soft material is capable of bidirectional deformation when near-infrared many researchers have studied the movement of snakes. [34] Wang et al. reported a snake-like soft robot consisting of a

A fast-response SMA artificial muscle integrated with hydrogel and thermoelectric materials

“…Furthermore, the excellent biocompatibility and flexibility of soft robots avoid the limitations of rigid counterparts. Consequently, many researchers have studied a wide range of soft robots with various modes of locomotion, e.g., crawling [2] , rolling, jumping, and underwater robots [3] .…”