Improved electromechanical behavior in castable dielectric elastomer actuators

Akbari, Samin; Rosset, Samuel; Shea, Herbert

doi:10.1063/1.4793420

Cited by 66 publications

(60 citation statements)

References 19 publications

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“…There is significant potential to improve the robots swimming performance by optimizing mechanical parameters. Optimal pre-stretch and thickness of the DEAs increase actuation strokes and forces (e.g., [9], [20]), and hence speed and thrust. In the jellyfish robot, the pre-stretch also modifies the bell shape, linked to drag, and can lead to higher locomotion speed.…”

Section: Discussionmentioning

confidence: 99%

“…Further characterization of swimming speed, thrust, and tail amplitude as a function of the drive voltage and frequency should be performed for different device geometries. Modeling the robots can establish stronger design principles, using analytical and finite element methods based on hyperelastic material models that are often used for modeling DEAs (e.g., [9], [20]). …”

Section: Discussionmentioning

confidence: 99%

“…DEAs exhibit high compliance (∼1 MPa of elastic modulus), large actuation strokes (e.g., 85 % of linear strain [9]), fast response time (less than 200 µs [10]), and theoretically high electromechanical efficiency (max. 90 % [6]).…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Biomimetic underwater robots based on dielectric elastomer actuators

Shintake

Shea

Floreano

2016

2016 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS)

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Abstract-Dielectric elastomer actuators (DEAs), a soft actuator technology, hold great promise for biomimetic underwater robots. The high-voltages required to drive DEAs can however make them challenging to use in water. This paper demonstrates a method to create DEA-based biomimetic swimming robots that operate reliably even in conductive liquids. We ensure the insulation of the high-voltage DEA electrodes without degrading actuation performance by laminating silicone layers. A fish and a jellyfish were fabricated and tested in water. The fish robot has a length of 120 mm and a mass of 3.8 g. The jellyfish robot has a 61 mm diameter for a mass of 2.6 g. The measured swimming speeds for a periodic 3 kV drive voltage were ∼8 mm/s for the fish robot, and ∼1.5 mm/s for the jellyfish robot.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

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Biomimetic underwater robots based on dielectric elastomer actuators

Shintake

Shea

Floreano

2016

2016 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS)

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“…The later being a more suitable approach for DEAs since it affects only t m , unlike pre-stretching which also modifies Y. 17 Typical DEAs have membranes in the 20 to 100 lm-range. Below those thicknesses, the fabrication becomes challenging and membrane quality is critical given the very large electric fields applied.…”

mentioning

confidence: 99%

Printing low-voltage dielectric elastomer actuators

Poulin

Rosset

Shea

2015

Applied Physics Letters

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136

126

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We demonstrate the fabrication of fully printed thin dielectric elastomer actuators (DEAs), reducing the operation voltage below 300 V while keeping good actuation strain. DEAs are soft actuators capable of strains greater than 100% and response times below 1 ms, but they require driving voltage in the kV range, limiting the possible applications. One way to reduce the driving voltage of DEAs is to decrease the dielectric membrane thickness, which is typically in the 20–100 μm range, as reliable fabrication becomes challenging below this thickness. We report here the use of pad-printing to produce μm thick silicone membranes, on which we pad-print μm thick compliant electrodes to create DEAs. We achieve a lateral actuation strain of 7.5% at only 245 V on a 3 μm thick pad-printed membrane. This corresponds to a ratio of 125%/kV2, by far the highest reported value for DEAs. To quantify the increasing stiffening impact of the electrodes on DEA performance as the membrane thickness decreases, we compare two circular actuators, one with 3 μm- and one with 30 μm-thick membranes. Our experimental measurements show that the strain uniformity of the 3 μm-DEA is indeed affected by the mechanical impact of the electrodes. We developed a simple DEA model that includes realistic electrodes of finite stiffness, rather than assuming zero stiffness electrodes as is commonly done. The simulation results confirm that the stiffening impact of the electrodes is an important parameter that should not be neglected in the design of thin-DEAs. This work presents a practical approach towards low-voltage DEAs, a critical step for the development of real world applications.

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“…Among the different existing hyperelastic models, the Gent model is often used in theoretical analyses of DEAs, [3][4][5][6][7][8] because it can model the limiting stretch that an elastomer can sustain, when its chains are completely stretched. Some other common models, such as neo-Hookean or Yeoh, do not show the existance of a maximal stretch.…”

Section: Introductionmentioning

confidence: 99%

An instrument to obtain the correct biaxial hyperelastic parameters of silicones for accurate DEA modelling

et al. 2014

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The analytical formulas describing the behaviour of dielectric elastomer actuators (DEAs) are based on hyperelastic strain energy density functions. The analytical modelling of a DEA will only lead to meaningful results if the dielectric elastomer can be accurately represented by the chosen hyperelastic model and if its parameters are carefully matched to the elastomer. In the case of silicone elastomers, we show that the strain energy density of a thin elastomeric membrane depends on the maximum deformation the membrane was previously submitted to (Mullins effect). We also show that using model parameters coming from an uniaxial pull-test to predict the behaviour of the elastomer in an equi-biaxial configuration leads to erroneous results. We have therefore built a measurement setup, which allows testing thin elastomeric membranes under equi-biaxial stress by inflating them with a pressure source. When modelling a DEA under equi-biaxial stretch, the measurement data can be used directly, without the need of an hyperelastic model, leading to voltage-stretch prediction closer the the measured stress-stretch behaviour of the dielectric membrane.

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Improved electromechanical behavior in castable dielectric elastomer actuators

Cited by 66 publications

References 19 publications

Biomimetic underwater robots based on dielectric elastomer actuators

Biomimetic underwater robots based on dielectric elastomer actuators

Printing low-voltage dielectric elastomer actuators

An instrument to obtain the correct biaxial hyperelastic parameters of silicones for accurate DEA modelling

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