A dynamic electrically driven soft valve for control of soft hydraulic actuators

Xu, Siyi; Chen, Yufeng; Hyun, Nak-seung Patrick; Becker, Kaitlyn P.; Wood, Robert J.

doi:10.1073/pnas.2103198118

Cited by 40 publications

(25 citation statements)

References 52 publications

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“…The maximum energy and power output densities of PHDE are superior to those of natural muscles and DEAs developed in recent years (Fig. 2D) (2,24,(27)(28)(29)(30)(31), which enable lightweight, energy-dense actuation systems. A PHDE film was demonstrated to toss an aluminum ball, which is 20 times as heavy as itself, to 12.1 cm high (Fig.…”

mentioning

confidence: 99%

A processable, high-performance dielectric elastomer and multilayering process

Shi

Askounis

Plamthottam

et al. 2022

Science

137

107

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Dielectric elastomers (DEs) can act as deformable capacitors that generate mechanical work in response to an electric field. DEs are often based on commercial acrylic and silicone elastomers. Acrylics require prestretching to achieve high actuation strains and lack processing flexibility. Silicones allow for processability and rapid response but produce much lower strains. In this work, a processable, high-performance dielectric elastomer (PHDE) with a bimodal network structure is synthesized, and its electromechanical properties are tailored by adjusting cross-linkers and hydrogen bonding within the elastomer network. The PHDE exhibits a maximum areal strain of 190% and maintains strains higher than 110% at 2 hertz without prestretching. A dry stacking process with high efficiency, scalability, and yield enables multilayer actuators that maintain the high actuation performance of single-layer films.

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mentioning

confidence: 99%

A processable, high-performance dielectric elastomer and multilayering process

Shi

Askounis

Plamthottam

et al. 2022

Science

137

107

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“…We constructed the DEAs using a low-viscoelasticity and high–dielectric strength silicone material, Elastosil P7670 (Wacker Chemical). From a previous study ( 45 ), a multilayer rolled DEA made from P7670 silicone exhibited a large quality factor of six and a high breakdown field of 66 V μm −1 under AC excitation. Owing to the material properties of silicone, these DEAs reached an estimated energy density of 4.9 J kg −1 and had sufficient bandwidth (600 Hz or higher) for the pump goals ( 45 ).…”

Section: Resultsmentioning

confidence: 82%

“…S1). A DEA structure contained two rolled DEAs combined in parallel, with each DEA consisting of sequentially layered carbon nanotube electrodes and elastomer sheets ( 44 , 45 ). Two or more DEAs were aligned in parallel and mounted to the top plate of the mechanical frame, with their free ends in contact with the channel via indenters.…”

Section: Resultsmentioning

confidence: 99%

A compact DEA-based soft peristaltic pump for power and control of fluidic robots

Nunez

Souri

et al. 2023

Sci. Robot.

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Fluid-driven robotic systems typically use bulky and rigid power supplies, considerably limiting their mobility and flexibility. Although various forms of low-profile soft pumps have been demonstrated, they either are limited to specific working fluids or generate limited flow rates or pressures, making them ill-suited for widespread robotics applications. In this work, we introduce a class of centimeter-scale soft peristaltic pumps for power and control of fluidic robots. An array of high power density robust dielectric elastomer actuators (DEAs) (each weighing 1.7 grams) were adopted as soft motors, operated in a programmed pattern to produce pressure waves in a fluidic channel. We investigated and optimized the dynamic performance of the pump by analyzing the interaction between the DEAs and the fluidic channel with a fluid-structure interaction finite element model. Our soft pump achieved a maximum blocked pressure of 12.5 kilopascals and a run-out flow rate of 39 milliliters per minute with a response time of less than 0.1 second. The pump can generate bidirectional flow and adjustable pressure through control of drive parameters such as voltage and phase shift. Furthermore, the use of peristalsis makes the pump compatible with various liquids. To illustrate the versatility of the pump, we demonstrate mixing a cocktail, powering custom actuators for haptic devices, and performing closed-loop control of a soft fluidic actuator. This compact soft peristaltic pump opens up possibilities for future on-board power sources for fluid-driven robots in a variety of applications, including food handling, manufacturing, and biomedical therapeutics.

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“…To define the target ranges for output and input pressures, we surveyed soft actuators and microfluidic circuits. The ranges of values noted here and in the remainder of this section will be used to define the ranges of our targets for the metrics mentioned; despite quoted data for these measurements being sparse in the literature, we found that a common command input for soft actuators is 103.4 kPa [22][23][24][25][26][27][28] while microfluidic output signals vary from 3.4 to 34.5 kPa due to the large resistances of the narrow channels which cause a large pressure drop limiting the output pressure at flow rates relevant to typical soft fluidic actuators. [29] Therefore, a gain range that guarantees that all microfluidic output signal magnitudes can be amplified to drive the largest soft robotic loads is 3-30.…”

Section: Performance Metricsmentioning

confidence: 99%

High‐Gain Microfluidic Amplifiers: The Bridge between Microfluidic Controllers and Fluidic Soft Actuators

Hevia

McCann

Bell

et al. 2022

Advanced Intelligent Systems

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Soft fluidic robots are typically controlled using manifolds containing large and rigid electromechanical valves. These bulky controllers limit scalability and hinder motion, in particular for untethered soft robots. There has been recent interest in using fluidic controllers analogous to electrical logic gates and microcontrollers to replace rigid valve systems. However, these microfluidic networks typically operate with small volumes, low flow rates, and low pressures relative to what is needed to power fluidic soft actuators. This article presents the design, fabrication, and analysis of a soft, fluidic amplifier as the “missing link” between microfluidic analogies of microcontrollers and the high fluidic power loads representative of soft actuators. The article demonstrates amplification gains of pressure signals up to a factor of four. The amplifier is a step toward fully autonomous soft robots by allowing designers to develop control strategies from soft materials with minimal additional rigid components or tethering.

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A dynamic electrically driven soft valve for control of soft hydraulic actuators

Cited by 40 publications

References 52 publications

A processable, high-performance dielectric elastomer and multilayering process

A processable, high-performance dielectric elastomer and multilayering process

A compact DEA-based soft peristaltic pump for power and control of fluidic robots

High‐Gain Microfluidic Amplifiers: The Bridge between Microfluidic Controllers and Fluidic Soft Actuators

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