Flagellate Underwater Robotics at Macroscale: Design, Modeling, and Characterization

Costanza Armanini, Madiha Farman, Marcello Calisti, Francesco Giorgio-Serchi, Cesare Stefanini, Federico Renda

Research output: Contribution to journalArticlepeer-review

19 Scopus citations


Prokaryotic flagellum is considered as the only known example of a biological 'wheel,' a system capable of converting the action of rotatory actuator into a continuous propulsive force. For this reason, flagella are an interesting case study in soft robotics and they represent an appealing source of inspiration for the design of underwater robots. A great number of flagellum-inspired devices exists, but these are all characterized by a size ranging in the micrometer scale and mostly realized with rigid materials. Here, we present the design and development of a novel generation of macroscale underwater propellers that draw their inspiration from flagellated organisms. Through a simple rotatory actuation and exploiting the capability of the soft material to store energy when interacting with the surrounding fluid, the propellers attain different helical shapes that generate a propulsive thrust. A theoretical model is presented, accurately describing and predicting the kinematic and the propulsive capabilities of the proposed solution. Different experimental trials are presented to validate the accuracy of the model and to investigate the performance of the proposed design. Finally, an underwater robot prototype propelled by four flagellar modules is presented.

Original languageBritish English
Pages (from-to)731-747
Number of pages17
JournalIEEE Transactions on Robotics
Issue number2
StatePublished - 1 Apr 2022


  • biologically-inspired robots
  • marine robotics
  • modeling, control, and learning for soft robots
  • Soft robot applications


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