Dielectric Elastomer Generators: How Much Energy Can Be Converted?

Koh, Soo Jin Adrian; Keplinger, Christoph; Li, Tiefeng; Bauer, Siegfried; Suo, Zhigang

doi:10.1109/tmech.2010.2089635

Cited by 325 publications

(301 citation statements)

References 29 publications

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“…102 Using a similar approach, but with four failure modes, the additional one being "loss of tension" in the membrane, Koh et al tracked potential energy cycles on voltage-charge and stress-stretch planes to identify cycles of maximum energy conversion. 103,104 Their plots can be used for defining permissible and safe energy harvesting cycles for natural rubber and VHB acrylic (Fig. 21).…”

Section: Energy Harvestingmentioning

confidence: 99%

Multi-functional dielectric elastomer artificial muscles for soft and smart machines

Anderson

Gisby²,

McKay³

et al. 2012

Journal of Applied Physics

559

314

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Dielectric elastomer (DE) actuators are popularly referred to as artificial muscles because their impressive actuation strain and speed, low density, compliant nature, and silent operation capture many of the desirable physical properties of muscle. Unlike conventional robots and machines, whose mechanisms and drive systems rapidly become very complex as the number of degrees of freedom increases, groups of DE artificial muscles have the potential to generate rich motions combining many translational and rotational degrees of freedom. These artificial muscle systems can mimic the agonist-antagonist approach found in nature, so that active expansion of one artificial muscle is taken up by passive contraction in the other. They can also vary their stiffness. In addition, they have the ability to produce electricity from movement. But departing from the high stiffness paradigm of electromagnetic motors and gearboxes leads to new control challenges, and for soft machines to be truly dexterous like their biological analogues, they need precise control. Humans control their limbs using sensory feedback from strain sensitive cells embedded in muscle. In DE actuators, deformation is inextricably linked to changes in electrical parameters that include capacitance and resistance, so the state of strain can be inferred by sensing these changes, enabling the closed loop control that is critical for a soft machine. But the increased information processing required for a soft machine can impose a substantial burden on a central controller. The natural solution is to distribute control within the mechanism itself. The octopus arm is an example of a soft actuator with a virtually infinite number of degrees of freedom (DOF). The arm utilizes neural ganglia to process sensory data at the local “arm” level and perform complex tasks. Recent advances in soft electronics such as the piezoresistive dielectric elastomer switch (DES) have the potential to be fully integrated with actuators and sensors. With the DE switch, we can produce logic gates, oscillators, and a memory element, the building blocks for a soft computer, thus bringing us closer to emulating smart living structures like the octopus arm. The goal of future research is to develop fully soft machines that exploit smart actuation networks to gain capabilities formerly reserved to nature, and open new vistas in mechanical engineering.

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Section: Energy Harvestingmentioning

confidence: 99%

Multi-functional dielectric elastomer artificial muscles for soft and smart machines

Anderson

Gisby²,

McKay³

et al. 2012

Journal of Applied Physics

559

314

View full text Add to dashboard Cite

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“…5 Theoretical estimates show a huge specific electrical energy generated per cycle up to 1:7 J=g with off-the-shelf materials. 6 DEGs have been employed in the heel of shoes for energy harvesting from walking. Durability in sea water environment and impedance matching of ocean waves and elastomer membranes make DEGs a promising candidate for off-shore wave energy harvesting.…”

mentioning

confidence: 99%

“…The experiment determines the specific electrical energy generated per cycle, the specific average power, and the mechanical to electrical energy conversion efficiency. Following suggestions made in our previous theoretical work, 2,6 we operate the generator between two charge reservoirs of different voltages and describe the cycle of energy conversion in work-conjugate planes.…”

mentioning

confidence: 99%

Method for measuring energy generation and efficiency of dielectric elastomer generators

Kaltseis¹,

Keplinger²,

Baumgartner³

et al. 2011

Applied Physics Letters

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113

155

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Dielectric elastomer generators convert mechanical into electrical energy at high energy density, showing promise for large and small scale energy harvesting. We present an experiment to monitor electrical and mechanical energy flows separately and show the cycle of energy conversion in work-conjugate planes. A specific electrical energy generated per cycle of 102mJ/g, at a specific average power of 17mW/g, is demonstrated with an acrylic elastomer in a showcase generation cycle. The measured mechanical to electrical energy conversion efficiency is 7.5%. The experiment may be used to assess the aptitude of specifically designed elastomers for energy harvesting.

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“…The energy harvesting cycle produced using the circuit is schematically described on the voltage charge plane in figure 5. The greater the area of the energy harvesting cycle, the more energy is harvested [5,16,17]. We were interested in optimizing the amount of energy that we can harvest from a specific generator.…”

Section: Methodsmentioning

confidence: 99%

Dielectric elastomer generators that stack up

McKay¹,

Rosset²,

Anderson³

et al. 2014

Smart Mater. Struct.

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This paper reports the design, fabrication, and testing of a soft dielectric elastomer power generator with a volume of less than 1 cm 3 . The generator is well suited to harvest energy from ambient and from human body motion as it can harvest from low frequency (sub-Hz) motions, and is compact and lightweight. Dielectric elastomers are highly stretchable variable capacitors. Electrical energy is produced when the deformation of a stretched, charged dielectric elastomer is relaxed; like-charges are compressed together and opposite-charges are pushed apart, resulting in an increased voltage. This technology provides an opportunity to produce soft, high energy density generators with unparalleled robustness. Two major issues block this goal: current configurations require rigid frames that maintain the dielectric elastomer in a prestretched state, and high energy densities have come at the expense of short lifetime. This paper presents a selfsupporting stacked generator configuration which does not require rigid frames. The generator consists of 48 generator films stacked on top of each other, resulting in a structure that fits within an 11 mm diameter footprint while containing enough active material to produce useful power. To ensure sustainable power production, we also present a mathematical model for designing the electronic control of the generator which optimizes energy production while limiting the electrical stress on the generator below failure limits. When cyclically compressed at 1.6 Hz, our generator produced 1.8 mW of power, which is sufficient for many low-power wireless sensor nodes. This performance compares favorably with similarly scaled electromagnetic, piezoelectric, and electrostatic generators. The generator's small form factor and ability to harvest useful energy from low frequency motions such as tree swaying or shoe impact provides an opportunity to deliver power to remote wireless sensor nodes or to distributed points in the human body without the need for costly periodic battery replacement.

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Dielectric Elastomer Generators: How Much Energy Can Be Converted?

Cited by 325 publications

References 29 publications

Multi-functional dielectric elastomer artificial muscles for soft and smart machines

Multi-functional dielectric elastomer artificial muscles for soft and smart machines

Method for measuring energy generation and efficiency of dielectric elastomer generators

Dielectric elastomer generators that stack up

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