Bistable Actuation in Multi-DoF Soft Robotic Modules Driven by Rolled Dielectric Elastomer Actuators

Prechtl, Johannes; Kunze, Julian; Bruch, Daniel; Seelecke, Stefan; Rizzello, Gianluca

doi:10.1109/robosoft51838.2021.9479246

Cited by 9 publications

(20 citation statements)

References 14 publications

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“…As a final remark, we point out that the RDEA must be axially pre-loaded in order to generate a stroke. The pre-load can be supplied, e.g., through a biasing mechanism, e.g., a mass, a spring, or a nonlinear mechanism [14,35]. The choice of the biasing element turns out to be highly critical for the performance of the overall actuator system.…”

Section: System Descriptionmentioning

confidence: 99%

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Modeling and experimental validation of thin, tightly rolled dielectric elastomer actuators

Prechtl¹,

Kunze²,

Moretti³

et al. 2021

Smart Mater. Struct.

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Due to their large deformation, high energy density, and high compliance, dielectric elastomer actuators (DEAs) have found a number of applications in several areas of mechatronics and robotics. Among the many types of DEAs proposed in the literature, rolled DEAs (RDEAs) represent one of the most popular configurations. RDEAs can be effectively used as compact muscle-like actuators for soft robots, since they allow eliminating the need for external motors or compressors while providing at the same time a flexible and lightweight structure with self-sensing capabilities. To effectively design and control complex RDEA-driven systems and robots, accurate and numerically efficient mathematical models need to be developed. In this work, we propose a novel lumped-parameter model for silicone-based, thin and tightly rolled RDEAs. The model is grounded on a free-energy approach, and permits to describe the electro-mechanically coupled response of the transducer with a set of nonlinear ordinary differential equations. After deriving the constitutive relationships, the model is validated by means of an extensive experimental campaign, conducted on three RDEA specimens having different geometries. It is shown how the developed model permits to accurately predict the effects of several parameters (external load, applied voltage, actuator geometry) on the RDEA electro-mechanical response, while maintaining an overall simple mathematical structure.

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Section: System Descriptionmentioning

confidence: 99%

“…This way, a thin artificial muscle actuator is obtained, capable to respond to an applied voltage with an increase of its length. The lack of a hollow core makes these type of actuators particularly compact, and attractive for applications where high-density linear actuation is required, such as soft robotic tentacle arms [35].…”

Section: System Descriptionmentioning

confidence: 99%

Modeling and experimental validation of thin, tightly rolled dielectric elastomer actuators

Prechtl¹,

Kunze²,

Moretti³

et al. 2021

Smart Mater. Struct.

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show abstract

Section: Resultsmentioning

confidence: 99%

“…In previous studies of DEAs with bistable structures, additional flexible elements were used to overcome the singularities, critically increasing the weight and size of the robot. [29][30][31] The lightweight design of the Hub (Figure 2D) holds two SCRs while flying with sufficient stiffness to withstand the landing impact. The Hub has three components that include 1) a Core with two side arms to hold the SCRs during the flight; 2) an Adhesive pad for perching onto the target surface and acting as a shock absorber during perching; and 3) a Skirt that works as a pressure chamber (i.e., piston) for launching the robot to a distant surface.…”

Section: Design Of the Tasering Twin Soft Robotmentioning

confidence: 99%

Tasering Twin Soft Robot: A Multimodal Soft Robot Capable of Passive Flight and Wall Climbing

Sriratanasak

Axinte

Dong

et al. 2022

Advanced Intelligent Systems

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The application of Soft Crawling Robots (SCRs) to real‐world scenarios remains a grand challenge due to their limited deployment time to reach the target and accessibility to difficult‐to‐reach environments by any obstacles. To overcome these limitations, a novel multimodal Tasering Twin Soft Robot (TTSR), carrying two SCRs, capable of 1) passive flight and 2) wall climbing to a desired location by deploying SCRs once reached the target is proposed. For satisfying both tasks, reconfigurable design of SCRs using a novel bistable mechanism and detaching mechanism based on a shape‐memory alloy for deploying SCRs is proposed. Each SCR is driven by two dielectric elastomer actuators (DEA) and three electroadhesive (EA) feet. To demonstrate multimodality, the TTSR with two SCRs is launched by pneumatic pressure and flown over an obstacle. While flying, the SCRs are folded compactly to reduce the air drag and perch on a wall 3 m away (50 times of body length) within 0.64 s. After perching, the SCRs reconfigure themselves for crawling and separated from each other. After that, the SCRs crawl, performing planar motion, and reach predefined locations on the wall. Moreover, the SCR can move across 15°‐slope dihedral surfaces and inverted surface.

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“…Many different types of soft actuators are available for soft robotic systems [9,10]. Among them, and bi-stable movement [19][20][21][22]. Furthermore, DEAs can also self-sense their deformations [23].…”

Section: Introductionmentioning

confidence: 99%

Characterization of slide ring materials for dielectric elastomer actuators

Shintake

Matsuno

Baba

et al. 2022

Smart Mater. Struct.

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This paper investigates the characteristics of sliding ring materials (SRMs), which are promising elastomeric materials for dielectric elastomer actuators (DEAs). Two different types of SRMs with Young's modulus of 0.8 MPa and 3.3 MPa, respectively, are prepared, and their material and mechanical properties and electro-mechanical performances at electric fields of up to 30 V/um are characterized. For comparison, the same tests are also performed on several commercially available elastomers: Elastosil 2030, Ecoflex 00-30, CF19-2186, and VHB 4905. The results reveal that SRMs demonstrate negligible Mullins effect and hysteresis, while their dielectric strength (62.4‒112.4 V/µm) and viscoelasticity (tan⁡δ 0.07‒0.24 at 10 Hz) are comparable or even superior to those of other elastomers. In addition, elongation at break is found to be 163.8‒172.1%. SRMs exhibit excellent electro-mechanical performance; for instance, one of the two types has an actuation force 293.2 mN at 24.9 V/µm and a strain of 5.2% at 22.3 V/µm. These values are the largest or larger than most of the tested elastomers. The high performance of SRMs results from their dielectric constant, which ranges from 10.3‒13.4, leading to an electro-mechanical sensitivity of up to 15.3 MPa-1. These results illustrate SRMs as attractive material options for DEAs.

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Bistable Actuation in Multi-DoF Soft Robotic Modules Driven by Rolled Dielectric Elastomer Actuators

Cited by 9 publications

References 14 publications

Modeling and experimental validation of thin, tightly rolled dielectric elastomer actuators

Modeling and experimental validation of thin, tightly rolled dielectric elastomer actuators

Tasering Twin Soft Robot: A Multimodal Soft Robot Capable of Passive Flight and Wall Climbing

Characterization of slide ring materials for dielectric elastomer actuators

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