Research ArticleSOFT ROBOTS

Electro-ribbon actuators and electro-origami robots

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Science Robotics  19 Dec 2018:
Vol. 3, Issue 25, eaau9795
DOI: 10.1126/scirobotics.aau9795
  • Fig. 1 Electro-origami and electro-ribbon actuator concept.

    (A) Diagrams of actuated electro-origami fold, with charge distribution. (B) Photographs of actuated electro-origami fold. (C) Effect of droplet volume on pull-in voltage for a zipping electro-origami fold. (D) Diagram of electro-ribbon actuator. (E) Voltage, current, and displacement during isotonic actuation of an electro-ribbon actuator. (F) Manufacture of standard electro-ribbon actuators. (G) Photographs of standard electro-ribbon actuator, which is made from thin steel electrodes and PVC tape: plan view and lifting a 20-g mass. Scale bars, 10 mm.

  • Fig. 2 Electro-ribbon actuator characterization.

    (A) Isometric tensile force at 0.1-mm actuator extension. (Insets) Electro-origami zipping. (B) Isometric tensile force at an applied voltage of 6 kV, with inset diagrams showing extension state. Points in (A) and (B) are averages of five trials for one sample, and error bars show SD between trials; intersample variance was low (fig. S4, D and E). (C) Bandwidth testing, showing full-amplitude contraction at 0.125 Hz and partial-amplitude oscillation at 5 and 10 Hz. (D) Cyclic testing over 100 thousand cycles. (E) Voltage, current, and electrical power traces during an experiment to measure efficiency. (F) Mechanical power output testing. The peak and average specific powers were 103.51 and 51.45 W kg−1, respectively. (G to I) Electro-ribbon actuator maximum stroke and load lifted variation with electrode thickness, length, and width, respectively. Scale bar, 10 mm.

  • Fig. 3 Electro-ribbon actuators made with different stiffness and from different materials.

    (A) A high-stress actuator lifting 410 g. (B) A high-stroke actuator lifting 10.75 g. (C) Electro-ribbon actuator made from ITO-coated PET lifting a 5-g mass. (D) A 3D printed electro-ribbon actuator, featuring 3D-printed graphene-loaded PLA conductors and a 3D-printed pure PLA insulator. (E) Electro-ribbon actuator made from pencil and paper lifting a 3-g mass. Scale bars, 10 mm.

  • Fig. 4 Electro-ribbon actuators integrated into multiactuator structures.

    Series (A), parallel (B), and lattice (C) configurations of electro-ribbon actuators. Scale bars, 20 mm.

  • Fig. 5 Other electro-origami actuators.

    (A) Prebent electro-ribbon actuator that does not require preloading before actuation. (B) Electro-origami spiral that wraps around itself when actuated. (C) Electro-origami actuator inspired by spider silk, spooling around a central cylinder in the same manner that spider silk spools around liquid droplets [inset photographs provided by authors of (32)]. Scale bars, 20 mm.

  • Fig. 6 Electro-origami devices.

    (A) Multifunctional electro-origami design, which can be used to make four unique functional devices. (B) Electro-origami solenoid actuator. (C) Electro-origami adaptive gripper, which also benefits from electroadhesive forces. (D) Electro-origami cilium structure, which drives a beam tip along a ciliate motion path. (E) Electro-origami locomotion robot, which can move left or right depending on the direction of sequential electrode charging. (F) Electro-origami fan that closes when activated. (G) Electro-origami muscle inspired by paper springs. (H) Electro-origami crane that flaps its wings when actuated. Scale bars, 10 mm.

  • Table 1 Dimensions, masses, actuator contractions, and descriptions of steel PVC electro-ribbon actuators.

    In all electro-ribbon actuators, the electrode width was 12.7 mm, and the insulator consisted of two layers of 130-μm-thick PVC tape.

    Electrode
    length (mm)
    Electrode
    thickness (mm)
    Conductor and
    insulator mass (g)
    Actuator
    contraction (%)
    Description
    Standard100502.2899.38
    High force10010002523.93Actuator force: 12.91 N
    High stress101000.933.91Stress: 40.77 kPa
    High contraction200202.9599.84Contraction: 99.84%
    High-contraction rate10050013.281.48Average contraction rate: 1161% s−1
    Peak contraction rate: 1985% s−1
    High specific force10500.3617.05Specific force: 10164.25 N kg−1
    High specific energy100502.2899.38Specific energy: 6.8809 J kg−1
    High specific power10050013.281.48Average specific power: 51.45 W kg−1
    Peak specific power: 103.41 W kg−1
    High energy density10500.6368.97Energy density: 44.17 kJ m−3
    High power density10050013.281.48Average power density: 424.45 kW m−3
    Peak power density: 853.83 kW−1
    Prebent70702.2496.30

Supplementary Materials

  • robotics.sciencemag.org/cgi/content/full/3/25/eaau9795/DC1

    Materials and Methods

    Fig. S1. Manufacture, field strength distribution, and experimental test setup of electro-origami fold.

    Fig. S2. Models used to derive electrostatic force.

    Fig. S3. Flowchart showing structure of a recursive MATLAB script.

    Fig. S4. Characterization and analysis of electro-ribbon actuator.

    Fig. S5. Results from electro-origami fold simulation.

    Fig. S6. Effect of material properties on performance of electro-origami fold.

    Table S1. Summary of materials used for electro-origami.

    Movie S1. An electro-origami fold.

    Movie S2. Isotonic and isometric actuation of a standard electro-ribbon actuator.

    Movie S3. Bandwidth testing of a standard electro-ribbon actuator.

    Movie S4. High-stress and high-contraction electro-ribbon actuators.

    Movie S5. High-power electro-ribbon actuator.

    Movie S6. Manufacture and testing of electro-ribbon actuators made from different materials.

    Movie S7. Series, parallel, and lattice arrangements of standard electro-ribbon actuators.

    Movie S8. Electro-origami actuators.

    Movie S9. Four electro-origami devices from one electro-origami design.

    Movie S10. Complex electro-origami devices.

  • Supplementary Materials

    The PDF file includes:

    • Materials and Methods
    • Fig. S1. Manufacture, field strength distribution, and experimental test setup of electro-origami fold.
    • Fig. S2. Models used to derive electrostatic force.
    • Fig. S3. Flowchart showing structure of a recursive MATLAB script.
    • Fig. S4. Characterization and analysis of electro-ribbon actuator.
    • Fig. S5. Results from electro-origami fold simulation.
    • Fig. S6. Effect of material properties on performance of electro-origami fold.
    • Table S1. Summary of materials used for electro-origami.
    • Legends for movies S1 to S10

    Download PDF

    Other Supplementary Material for this manuscript includes the following:

    • Movie S1 (.mp4 format). An electro-origami fold.
    • Movie S2 (.mp4 format). Isotonic and isometric actuation of a standard electro-ribbon actuator.
    • Movie S3 (.mp4 format). Bandwidth testing of a standard electro-ribbon actuator.
    • Movie S4 (.mp4 format). High-stress and high-contraction electro-ribbon actuators.
    • Movie S5 (.mp4 format). High-power electro-ribbon actuator.
    • Movie S6 (.mp4 format). Manufacture and testing of electro-ribbon actuators made from different materials.
    • Movie S7 (.mp4 format). Series, parallel, and lattice arrangements of standard electro-ribbon actuators.
    • Movie S8 (.mp4 format). Electro-origami actuators.
    • Movie S9 (.mp4 format). Four electro-origami devices from one electro-origami design.
    • Movie S10 (.mp4 format). Complex electro-origami devices.

    Files in this Data Supplement:

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