Finite element modelling of dielectric elastomer minimum energy structures

O’Brien, Benjamin; McKay, Thomas; Calius, Emilio P.; Xie, Shane; Anderson, Iain A.

doi:10.1007/s00339-008-4946-8

Cited by 100 publications

(82 citation statements)

References 15 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%

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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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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%

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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“…Examples include a mini-gripper 54 that opens when the voltage is on (Fig. 10), or an array of touchsensitive actuators for a conveyor, as developed by O'Brien et al 55 The latter device is described further in Sec. III.…”

Section: Multi-degree-of-freedom De Actuationmentioning

confidence: 99%

“…16) that enabled the use of planar membrane elements by including the electrostatic energy in the strain energy function. 55 Each actuator, when touched, produced a capacitance change that triggered actuation, and this resulted in a wave of motion from one end of the device to the other that pushed a cylindrical object supported on parallel rails forward (Fig. 17).…”

Section: Mechano-sensitivity Cyber-proprioception Cyber-pain mentioning

confidence: 99%

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

Anderson

Gisby²,

McKay³

et al. 2012

Journal of Applied Physics

548

307

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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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“…Until now, several different DEMES including modeling have been reported [16][17][18][19], and some attempts of developing robots have been presented [20,21]. However, currently there is no result regarding DEMES using PDMS, and, actuation performance such as actuation stroke, output force, and their relation on mechanical parameters to construct actuators have not fully investigated.…”

Section: Introductionmentioning

confidence: 99%

Effect of mechanical parameters on dielectric elastomer minimum energy structures

et al. 2013

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Soft robotics may provide many advantages compared to traditional robotics approaches based on rigid materials, such as intrinsically safe physical human-robot interaction, efficient/stable locomotion, adaptive morphology, etc. The objective of this study is to develop a compliant structural actuator for soft a soft robot using dielectric elastomer minimum energy structures (DEMES). DEMES consist of a pre-stretched dielectric elastomer actuator (DEA) bonded to an initially planar flexible frame, which deforms into an out-of-plane shape which allows for large actuation stroke. Our initial goal is a one-dimensional bending actuator with 90 degree stroke. Along with frame shape, the actuation performance of DEMES depends on mechanical parameters such as thickness of the materials and pre-stretch of the elastomer membrane. We report here the characterization results on the effect of mechanical parameters on the actuator performance. The tested devices use a cm-size flexible-PCB (polyimide, 50 µm thickness) as the frame-material. For the DEA, PDMS (approximately 50 µm thickness) and carbon black mixed with silicone were used as membrane and electrode, respectively. The actuators were characterized by measuring the tip angle and the blocking force as functions of applied voltage. Different pre-stretch methods (uniaxial, biaxial and their ratio), and frame geometries (rectangular with different width, triangular and circular) were used. In order to compare actuators with different geometries, the same electrode area was used in all the devices. The results showed that the initial tip angle scales inversely with the frame width, the actuation stroke and the blocking force are inversely related (leading to an interesting design trade-off), using anisotropic pre-stretch increased the actuation stroke and the initial bending angle, and the circular frame shape exhibited the highest actuation performance.

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Finite element modelling of dielectric elastomer minimum energy structures

Cited by 100 publications

References 15 publications

Biomimetic underwater robots based on dielectric elastomer actuators

Biomimetic underwater robots based on dielectric elastomer actuators

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

Effect of mechanical parameters on dielectric elastomer minimum energy structures

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