Untethered soft robotic jellyfish

Abstract

Inspired by natural creatures, soft robots possess the unique advantages of large actuation and excellent adaptability. Untethered designs of soft robots are drawing more attention to researchers, but current research is limited. Also, there is an increasing need to improve the performance of bio-mimetic robots. This work describes an untethered soft robotic jellyfish with high mobility that can mimic a natural jellyfish’s performance. The electrode of the robotic jellyfish is made by sandwiching carbon grease between two layers of dielectric elastomer film. The frame of the material, where six plastic paddles are attached, is made from a silicone elastomer. The robotic jellyfish has a maximum recorded swim speed of up to 1 cm s−1, with a peak thrust force of 0.000 12 N. A finite element simulation is developed to study the performance of the robotic jellyfish in a theoretical manner. By embedding a compact remote-controlled power source, the robotic jellyfish is made autonomous. In this case, the max peak speed is around 0.5 cm s−1. Ultimately, the working principles of the bio-mimetic robotic jellyfish can be useful in field studies and to guide the design of soft robots and flexible devices.

Multi-functional soft-bodied jellyfish-like swimming

“…The ability to utilize the fluidic flow to achieve multiple functions and tasks is independent of the magnetic field since the incurred flow structures only rely on the interplay between the robot body and the fluid. Therefore, the above design and swimming modes may potentially be realized by current or future jellyfish-like soft robots built with other on-board or off-board actuation methods 48 such as biological muscle cells 30 , shape memory alloys 5 , hydraulic actuators 1 , dielectric elastomers 2,49 , hydrogels 50 , and liquid crystal elastomers 51 .…”

“…Inspired by ephyra, we propose an untethered jellyfish-like soft millirobot, which could realize multiple functionalities by producing diverse controlled fluidic flows around its body using its lappets, which are actuated by magnetic composite elastomer and bent by remote magnetic fields. Using this experimental setup, we study five distinct swimming modes to particularly investigate the interaction between the robot’s soft body and incurred fluidic flows due to the robot’s body motion and utilize such physical interaction for predation-inspired object manipulation capability of the robot, in addition to the robot’s swimming propulsion, which has been the only focus of previous jellyfish-like robot studies 1,2,5,30 . The proposed soft robot’s different lappet motion kinematics are used to conduct four different robotic tasks: selectively trap and transport objects of two different sizes, burrow into granular media consisting of fine beads to either camouflage or search a target object, enhance the local mixing of two different chemicals, and generate a desired concentrated chemical path.…”

“…The magnetic composite elastomer is chosen here because it can be actuated and controlled wirelessly and fast by remote magnetic fields, which have minimal effects on the fluidic flow under investigation. Existing robots, including other jellyfish-like robots 1,2,5,30 , could also complete the same tasks if they generate the same proposed lappet kinematics and local flow structures at the same length and time scale. Moreover, the proposed soft robotic platform, which has similar size and fluidic flow generating behaviors as an ephyra, could be used to study the impacts of changing their morphology and kinematics, which can happen due to pollutants, ionic changes, and temperature variation, to their survivability and habitat 24,31–34 .…”

Jellyfish-Inspired Soft Robot Driven by Fluid Electrode Dielectric Organic Robotic Actuators

“…Their work demonstrated the ability to effectively swim and transport cargo, but required an external field for propulsion. Recently, Cheng et al demonstrated an untethered soft robotic jellyfish that was powered by dielectric elastomer actuators (DEAs) that swam with a maximum speed of 1 cm s −1 (Cheng et al, 2019 ). While the work of Cheng et al was the first demonstration of an untethered jellyfish-inspired robot powered by DEAs, their work relies upon a prestretched membrane and hydrogel electrodes.…”

Bioinspired Electromechanically Active Polymer-Based Robotics

“…19 Example of a bimorph bending DEA with oriented carbon fibers to constrain the defor-mation along predefined directions and therefore generate different actions (courtesy from Prof. David Clarke, Harvard University, USA) However, in this case, one of the two compliant electrodes required for actuation was replaced by the surrounding (conductive) water and the control electronics was embedded on board, obtaining an untethered (i.e., fully autonomous) robot. Plastic extensions were added to increase the thrust force (Cheng et al 2019).…”