Electromechanics of planar HASEL actuators

Kirkman, Sophie; Rothemund, Philipp; Acome, Eric; Keplinger, Christoph

doi:10.1016/j.eml.2021.101408

Cited by 11 publications

(5 citation statements)

References 38 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Specifically, this force is known as the Maxwell stress, which is found to be a fundamental principle for soft electrohydraulic actuators in the literature. [ 58 ] Short distance results in larger electrostatic forces, leading to more actuation strain. The amount of dielectric liquid determines the distance between the electrodes and hence the actuation strain, which can be seen in the data shown in Figure 6a,b, where different amounts of liquid (2 and 4 mL) are employed.…”

Section: Resultsmentioning

confidence: 99%

Biodegradable Electrohydraulic Soft Actuators

Kanno

Caruso

Takai

et al. 2023

Advanced Intelligent Systems

View full text Add to dashboard Cite

Biodegradable materials decompose and return to nature. This functionality can be applied to derive robotic systems that are environmentally friendly. This study presents a fully biodegradable soft actuator, which is one of the key elements in “green” soft robotics. The working of the actuator is based on an electrohydraulic principle, which is similar to that of hydraulically amplified self‐healing electrostatic actuators. The actuator developed in this study consists of a dielectric film made of polylactic acid (PLA) and polybutylene adipate‐co‐terephthalate (PBAT), with soybean oil as the dielectric liquid and electrodes made from a mixture of gelatin, glycerol, and sodium chloride (NaCl). The synthesized biodegradable electrode material exhibits a Young's modulus of 0.06 MPa and resistivity of 258 Ω·m when the mass fraction of NaCl relative to the amount of gelatin and glycerol is 10 wt%. The softness and resistivity of the electrode material results in actuation strain values of 3.2% (at 1 kV, corresponding to 1.2 kV mm−1) and 18.6% (at 10 kV, corresponding to 9.6 kV mm−1) for the linear‐type and circular‐type actuators, respectively. These values obtained for the biodegradable electrohydraulic soft actuators are comparable to those of nonbiodegradable actuators of the same type, representing the successful implementation of the concept.

show abstract

Section: Resultsmentioning

confidence: 99%

Biodegradable Electrohydraulic Soft Actuators

Kanno

Caruso

Takai

et al. 2023

Advanced Intelligent Systems

View full text Add to dashboard Cite

show abstract

“…The required actuation voltage of HASEL actuator designs can be decreased by reducing the thickness or by increasing the permittivity of the dielectric material (19,(27)(28)(29). Flexible polymers with high permittivity like polyvinylidene fluoride (PVDF) terpolymers have been successfully used to achieve high Maxwell stresses [>70 mN cm −2 V −1 (30)] at low voltages (<300 V) in compact electrostatic devices for haptic applications (30)(31)(32)(33).…”

Section: Background and Related Workmentioning

confidence: 99%

Low-voltage electrohydraulic actuators for untethered robotics

Gravert,

Varini,

Kazemipour

et al. 2024

Sci. Adv.

View full text Add to dashboard Cite

Rigid robots can be precise but struggle in environments where compliance, robustness to disturbances, or energy efficiency is crucial. This has led researchers to develop biomimetic robots incorporating soft artificial muscles. Electrohydraulic actuators are promising artificial muscles that perform comparably to mammalian muscles in speed and power density. However, their operation requires several thousand volts. The high voltage leads to bulky and inefficient driving electronics. Here, we present hydraulically amplified low-voltage electrostatic (HALVE) actuators that match mammalian skeletal muscles in average power density (50.5 watts per kilogram) and peak strain rate (971% per second) at a 4.9 times lower driving voltage (1100 volts) compared to the state of the art. HALVE actuators are safe to touch, are waterproof, and exhibit self-clearing properties. We characterize, model, and validate key performance metrics of our actuator. Last, we demonstrate the utility of HALVE actuators on a robotic gripper and a soft robotic swimmer.

show abstract

“…The discussion of a study reveals a different type of material used instead of polymer which is known as BOPP (Biaxially Oriented Polypropylene) [29]. Upon voltage activation, the potential difference creates an electric field in between the hydrogel electrodes that causes a Maxwell stress in the surface [30] and the contraction takes place as a result. The contraction can be varied depending on how the structure of the actuator is designed.…”

Section: Materials Selectionmentioning

confidence: 99%

“…Similar to the donut HASELs, the planar HASEL actuators are made of stretchable dielectric shell which has compliant electrode coatings on its surface and surrounded by a layer of dielectric liquid. A study shows that they can generate greater specific energy and a linear strain of 124% than natural muscle [30]. Upon electrical activation, they can expand in-plane.…”

Section: Planar Haselmentioning

confidence: 99%

The HASEL actuator’s muscle mimicking mechanism for enacting an upper limb smart prosthesis: A review on recent progress and challenges for future implementation

Anjum

2022

Preprint

View full text Add to dashboard Cite

Biomimicry is the method of adapting concepts from nature to produce more sustainable technologies for mankind. It is of particular interest to the biomedical soft robotic field specifically applied to smart prostheses. Unlike the typical prostheses that employs metal and geared actuators, a biomimicking smart prosthesis emphasizes on the use of highly complaint soft biocompatible materials. A recent advancement in this field is a biomimicking soft actuator known as the HASEL (Hydraulically Amplified Self-healing ELectrostatic) actuator. They represent a leap forward in the soft robotics field as they showcase many similarities with human muscles to the point that the actuator could easily be extended while in place. This paper reviews the susceptibility of the HASEL actuators for upper-limb smart prosthesis. We first reviewed the structural analysis of HASELs followed by their prevailing control system mechanisms. Finally, we concluded the paper by discussing the challenges for HASEL to be used as a smart prosthesis limiting to the upper-limb scenario.

show abstract

Electromechanics of planar HASEL actuators

Cited by 11 publications

References 38 publications

Biodegradable Electrohydraulic Soft Actuators

Biodegradable Electrohydraulic Soft Actuators

Low-voltage electrohydraulic actuators for untethered robotics

The HASEL actuator’s muscle mimicking mechanism for enacting an upper limb smart prosthesis: A review on recent progress and challenges for future implementation

Contact Info

Product

Resources

About