A jellyfish-inspired jet propulsion robot actuated by an iris mechanism

Kenneth Marut, Colin Stewart, Tyler Michael, Alex Villanueva, Shashank Priya

Research output: Contribution to journalArticlepeer-review

25 Citations (SciVal)


A jellyfish-inspired jet propulsion robot (JetPRo) is designed, fabricated, and characterized with the objective of creating a fast-swimming uncrewed undersea vehicle. JetPRo measures 7.9 cm in height, 5.7 cm in diameter and is designed to mimic the proficient jetting propulsion mechanism used by the hydromedusa Sarsia tubulosa, which measures approximately 1 cm in diameter. In order to achieve the uniform-bell contraction used by S. tubulosa, we develop a novel circumferential actuation technique based on a mechanical iris diaphragm. When triggered, this mechanism induces a volumetric change of a deformable silicone cavity to expel a jet of fluid and produces positive thrust. A theoretical jetting model is used to optimize JetPRo's gait for maximum steady-state swimming velocity, a result achieved by minimizing the timing between the contraction and relaxation phases. We validate this finding empirically and quantify the swimming performance of the robot using video tracking and time resolved digital particle image velocimetry. JetPRo was able to produce discrete vortex rings shed before pinch off and swim upwards with a maximum steady-state velocity of 11.6 cm s-1, outperforming current state-of-the-art robotic jellyfish in velocity as well as diameter-normalized velocity.

Original languageEnglish (US)
Article number094021
JournalSmart Materials and Structures
Issue number9
StatePublished - Sep 1 2013

All Science Journal Classification (ASJC) codes

  • Signal Processing
  • Electrical and Electronic Engineering
  • Atomic and Molecular Physics, and Optics
  • Civil and Structural Engineering
  • Condensed Matter Physics
  • Mechanics of Materials
  • Materials Science(all)


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