Jellyfish Inspired Underwater Systems and Technologies

Abstract

Unmanned underwater vehicles (UUVs) have long been in use but increasingly there has been a wave of biomimetic robots taking over the duties and functions of traditional vehicles. A robotic jellyfish, inspired by the species Aurelia aurita was developed and characterized. In addition to the body of the main robotic vehicle, supporting technologies were developed including polymeric artificial muscles, hydrogel-based artificial mesoglea, and an inclinometer inspired by the jellyfish statocyst organ. Through multiple versions, the vehicle was able to attain an order of magnitude increase in proficiency from 0.022 s?? to 0.21 s?? and robustness not found in initial prototypes. A polyvinyl alcohol hydrogel reinforced with ferritin nanoparticles was found to accurately mimic the stress and strain characteristics of natural Aurelia mesoglea while maintaining a high water content similar to the animal. In addition, the optical properties were shown to be controlled by water to DMSO ratio. A five layer PPy-Au-PVDF-Au-PPy actuator stored in 0.5M KCl solution actuated at 4 VDC potential and produced an impressive 90% tip deflection. In addition, the rate of change was extremely high at 50% deflection of initial actuator length per second. The artificial jellyfish statocyst was found to produce the required highly linear voltage divider output. This sensor will provide the vehicle with biomimetic self-awareness of its own body position. Future directions are proposed for the biomimetic robotic jellyfish such as on-board power and computing, multi-material mesoglea with a dermal layer, a MEMS-based statocyst, and polymeric muscles with increased force production and time response.