A laser-microfabricated electrohydrodynamic thruster for centimeter-scale aerial robots

PLoS One. 2020 Apr 29;15(4):e0231362. doi: 10.1371/journal.pone.0231362. eCollection 2020.

Abstract

To date, insect scale robots capable of controlled flight have used flapping-wings for generating lift, but this requires a complex and failure-prone mechanism. A simpler alternative is electrohydrodynamic (EHD) thrust, which requires no moving mechanical parts. In EHD, corona discharge generates a flow of ions in an electric field between two electrodes; the high-velocity ions transfer their kinetic energy to neutral air molecules through collisions, accelerating the gas and creating thrust. We introduce a fabrication process for EHD thruster based on 355 nm laser micromachining, which potentially allows for greater materials selection, such as fiber-based composites, than is possible with semiconductor-based lithographic processing. Our four-thruster device measures 1.8 × 2.5 cm and is composed of steel emitters and a lightweight carbon fiber mesh. We measured the electrical current and thrust of each thruster of our four-thruster design, showing agreement with the Townsend relation. The peak thrust of our device, at 5.2 kV, was measured to be 3.03 times its 37 mg (363.0 μN) mass using a precision balance. In free flight, we demonstrated liftoff at 4.6 kV.

Publication types

  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Electric Conductivity
  • Electrodes
  • Electronics*
  • Equipment Design
  • Lasers
  • Robotics

Grants and funding

This work partially supported by the Air Force Office of Scientific Research under grant no. FA9550-14-1-0398. There was no additional external funding received for this study. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.