Research ArticleBIOMIMETICS

Consecutive aquatic jump-gliding with water-reactive fuel

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Science Robotics  11 Sep 2019:
Vol. 4, Issue 34, eaax7330
DOI: 10.1126/scirobotics.aax7330
  • Fig. 1 Mission profile, robot operation, and design.

    (A) Proposed mission stages showcasing the transition from a floating state to an airborne jetting phase and back to floating. (B) 3D model render of the underside of the robot highlighting key features. (C) Section of fuel container, with fuel for one mission cycle, showing a water drop about to react with the calcium carbide.

  • Fig. 2 Jetting phase analysis.

    (A) Combustion during static jetting tests with transparent chamber (movie S5). (B) Volume of air (blue) and water (red) in the combustion chamber shown at 0, 100, and 160 ms during the water jetting phase. (C) Evolution of the water level and volume during jetting, showing that CFD and analytical predictions compare well. (D) Surface plot of analytical model output showing the effect of nozzle diameter and volume fraction on the height achieved by the robot when launched vertically. (E) Internal chamber pressure and thrust evolution for the jetting phase.

  • Fig. 3 Overview of the aerial-aquatic robot systems.

    (A) Bottom view schematics of the aircraft with the electronics on top of the combustion chamber. (B) Static pressure contours on robot body, and streamlines colored by velocity magnitude for a simulation at 8° angle of attack and freestream velocity of 10 m/s. (C) System diagram of the onboard electronics and transducers. (D) Side view photograph of the assembled jetting system showing the electronics under their transparent waterproof cover. (E) 1, water intake; 2, water pumping into fuel tank; 3, reaction to produce acetylene gas; 4, ignition; 5, water jetting, showing choked needle.

  • Fig. 4 Laboratory tests.

    (A) Time lapse of the landing process, refilling process, and subsequent launch. (B) Comparison of position and velocity profiles for the experiment and the analytical model. (C) Evolution of the position of the center of gravity as the robot empties, moving ahead of the center of lift. (D) Capture of a high-powered launch in the flight arena at the end of the water jetting phase (movie S2). (E) Robot during water escape (movie S3).

  • Fig. 5 Outdoor flight tests.

    (A) Composite image of the robot in floating, jetting, and flying mode (movie S4). A bystander on the sidewalk was edited out for clarity. (B) Pressure evolution of indoor and outdoor flights aligned at pressure peak. (C). Flight trajectory of a pond-to-grass launch.

Supplementary Materials

  • robotics.sciencemag.org/cgi/content/full/4/34/eaax7330/DC1

    Text S1. Analytic model derivation

    Text S2. Physics model implementation

    Text S3. Ignition study

    Text S4. Transparent static model development

    Text S5. Floating stability

    Fig. S1. Embedded code structure.

    Fig. S2. Laboratory setup.

    Fig. S3. Flight performance.

    Fig. S4. Buoyancy stability.

    Fig. S5. Possible launch range in waves.

    Fig. S6. Robot behavior in waves.

    Fig. S7. Inclination and expected performance in waves.

    Fig. S8. Tracked laboratory fight trajectory.

    Fig. S9. Animal and robot water-jumping height comparison.

    Table S1. Animal and robot water-jumping height comparison.

    Movie S1. Assembly.

    Movie S2. Laboratory flight tests at different angles.

    Movie S3. Demonstration of impulsive water escape.

    Movie S4. Demonstration of outdoor flights.

    Movie S5. Acetylene combustion tests.

    Movie S6. Demonstration of indoor flight with a launcher.

    Movie S7. Demonstration of landing and relaunching.

    Movie S8. Wave tests.

  • Supplementary Materials

    The PDF file includes:

    • Text S1. Analytic model derivation
    • Text S2. Physics model implementation
    • Text S3. Ignition study
    • Text S4. Transparent static model development
    • Text S5. Floating stability
    • Fig. S1. Embedded code structure.
    • Fig. S2. Laboratory setup.
    • Fig. S3. Flight performance.
    • Fig. S4. Buoyancy stability.
    • Fig. S5. Possible launch range in waves.
    • Fig. S6. Robot behavior in waves.
    • Fig. S7. Inclination and expected performance in waves.
    • Fig. S8. Tracked laboratory fight trajectory.
    • Fig. S9. Animal and robot water-jumping height comparison.
    • Table S1. Animal and robot water-jumping height comparison.

    Download PDF

    Other Supplementary Material for this manuscript includes the following:

    • Movie S1 (.mp4 format). Assembly.
    • Movie S2 (.mp4 format). Laboratory flight tests at different angles.
    • Movie S3 (.mp4 format). Demonstration of impulsive water escape.
    • Movie S4 (.mp4 format). Demonstration of outdoor flights.
    • Movie S5 (.mp4 format). Acetylene combustion tests.
    • Movie S6 (.mp4 format). Demonstration of indoor flight with a launcher.
    • Movie S7 (.mp4 format). Demonstration of landing and relaunching.
    • Movie S8 (.mp4 format). Wave tests.

    Files in this Data Supplement:

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