A Multistable Linear Actuation Mechanism Based on Artificial Muscles

In this paper, we report on a multistable linear actuation mechanism articulated with electroactive polymer actuators, widely known as artificial muscles. These actuators, which can operate both in wet and dry media under as small as 1.0 V potential difference, are fundamentally cantilever beams made of two electroactive polymer layers (polypyrrole) and a passive polyvinylidene fluoride substrate in between the electroactive layers. The mechanism considered is kinematically analogous to a four-bar mechanism with revolute-prismatic-revolute-prismatic pairs, converting the bending displacement of a polymer actuator into a rectilinear movement of an output point. The topology of the mechanism resembles that of bistable mechanisms operating under the buckling effect. However, the mechanism proposed in this paper can have many stable positions depending on the input voltage. After demonstrating the feasibility of the actuation concept using kinematic and finite element analyses of the mechanism, experiments were conducted on a real mechanism articulated with a multiple number (2, 4, or 8) of electroactive polymer actuators, which had dimensions of 12×2×0.17 mm3. The numerical and experimental results demonstrate that the angular displacement of the artificial muscles is accurately transformed into a rectilinear motion by the proposed mechanism. The higher the input voltage, the larger the rectilinear displacement. This study suggests that this multistable linear actuation mechanism can be used as a programmable switch and/or a pump in microelectromechanical systems (MEMS) by adjusting the input voltage and scaling down the mechanism further.

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Conjugated Polymer Actuators

MRS Bulletin ◽

10.1557/mrs2008.45 ◽

2008 ◽

Vol 33 (3) ◽

pp. 197-204 ◽

Cited By ~ 59

Author(s):

Elisabeth Smela

Keyword(s):

Conjugated Polymer ◽

Low Voltage ◽

High Strength ◽

Electroactive Polymer ◽

Artificial Muscles ◽

Polymer Actuators ◽

Actuation Mechanism ◽

Conjugated Polymer Actuators

AbstractConjugated polymer artificial muscles fill a unique niche in the electroactive polymer portfolio. They combine high strength, low voltage, and reasonable speed with versatile fabrication and design. This article reviews the actuation mechanism in these materials and presents some of the designs that have been developed for applications such as Braille displays, catheters, and bioMEMS devices.

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Electroactive polymer actuators as artificial muscles: are they ready for bioinspired applications?

Bioinspiration & Biomimetics ◽

10.1088/1748-3182/6/4/045006 ◽

2011 ◽

Vol 6 (4) ◽

pp. 045006 ◽

Cited By ~ 118

Author(s):

Federico Carpi ◽

Roy Kornbluh ◽

Peter Sommer-Larsen ◽

Gursel Alici

Keyword(s):

Electroactive Polymer ◽

Artificial Muscles ◽

Polymer Actuators

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Hysteresis in a Carbon Nanotube Based Electroactive Polymer Microfiber Actuator: Numerical Modeling

Journal of Nanoscience and Nanotechnology ◽

10.1166/jnn.2007.072 ◽

2007 ◽

Vol 7 (11) ◽

pp. 3974-3979 ◽

Cited By ~ 5

Author(s):

Kiwon Sohn ◽

Su Ryon Shin ◽

Sang Jun Park ◽

Seon Jeong Kim ◽

Byung-Ju Yi ◽

...

Keyword(s):

Carbon Nanotube ◽

Numerical Model ◽

Electrical Potential ◽

Hysteretic Behavior ◽

Electroactive Polymer ◽

Single Wall Carbon Nanotubes ◽

Micro Scale ◽

Polymer Actuators ◽

Electrical Potentials ◽

Polymer Actuator

Hysteretic behavior is an important consideration for smart electroactive polymer actuators in a wide variety of nano/micro-scale applications. We prepared an electroactive polymer actuator in the form of a microfiber, based on single-wall carbon nanotubes and polyaniline, and investigated the hysteretic characteristics of the actuator under electrical potential switching in a basic electrolyte solution. For actuation experiments, we measured the variation of the length of the carbon-nanotube-based electroactive polymer actuator, using an Aurora Scientific Inc. 300B Series muscle lever arm system, while electrical potentials ranging from 0.2 V to 0.65 V were applied. Based on the classical Preisach hysteresis model, we presented and validated a numerical model that described the hysteretic behavior of the carbon-nanotube-based electroactive polymer actuator. Inverse hysteretic behavior was also simulated using the model to demonstrate its capability to predict an input from a desired output. This numerical model of hysteresis could be an effective approach to micro-scale control of carbon-nanotube-based electroactive polymer actuators in potential applications.

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Development and modeling of a new ionogel based actuator

Journal of Intelligent Material Systems and Structures ◽

10.1177/1045389x16682841 ◽

2017 ◽

Vol 28 (15) ◽

pp. 2036-2050 ◽

Cited By ~ 5

Author(s):

Zhipeng Wang ◽

Bin He ◽

Xinhua Liu ◽

Qigang Wang

Keyword(s):

Electromechanical Coupling ◽

Chemical Properties ◽

Input Voltage ◽

Electrical Circuit ◽

Electroactive Polymer ◽

Beam Model ◽

Driving Voltage ◽

Polymer Actuators ◽

Driving Mechanisms ◽

Polymer Metal

Ionic electroactive polymer actuators are expected to be one of the most promising driving mechanisms in the future due to their extraordinary features such as their lightweight, flexibility, and low-energy consumption. Traditional ionic electroactive polymer actuators for example, ionic-polymer metal composites have a problem with durability in open air due to the evaporation of water contained in the polymer electrolytes, resulting in a corresponding loss of performance. Electrolysis of the water at relatively low operating voltages may cause deterioration of these materials. Ionic liquids are more thermally and electrochemically stable than water, with unique advantages including negligible volatility, low melting point and high ionic conductivity, therefore they can be used in the application of ionic electroactive polymer actuators. In this work, a new ionic electroactive polymer actuator based on ionogel is developed, which can be operated at low driving voltage with high electrochemical stability. In order to investigate the actuation mechanism of the actuator, a general model consisting of an equivalent electrical circuit, an electromechanical coupling term and a mechanical beam model is built up to characterize its interrelated electrical, mechanical, and chemical properties. This model explains the relationship between input voltage and bending displacement of the actuator. Theoretical and experimental results are demonstrated and documented to validate the conclusion that the model can effectively predict the actuation response of the material. The geometric scalability of the model is also investigated, giving support to the design of the soft mechanism based on ionogel.

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A Kirigami Approach of Patterning Membrane Actuators

Polymers ◽

10.3390/polym13010125 ◽

2020 ◽

Vol 13 (1) ◽

pp. 125

Author(s):

Harti Kiveste ◽

Rudolf Kiefer ◽

Rain Eric Haamer ◽

Gholamreza Anbarjafari ◽

Tarmo Tamm

Keyword(s):

Computer Simulations ◽

Polyvinylidene Fluoride ◽

Electroactive Polymers ◽

Electroactive Polymer ◽

Limiting Factor ◽

Polymer Actuators ◽

Membrane Type ◽

Membrane Actuators

Ionic electroactive polymer actuators are typically implemented as bending trilayer laminates. While showing high displacements, such designs are not straightforward to implement for useful applications. To enable practical uses in actuators with ionic electroactive polymers, membrane-type film designs can be considered. The significantly lower displacement of the membrane actuators due to the lack of freedom of motion has been the main limiting factor for their application, resulting in just a few works considering such devices. However, bioinspired patterning designs have been shown to significantly increase the freedom of motion of such membranes. In this work, we apply computer simulations to design cutting patterns for increasing the performance of membrane actuators based on polypyrrole doped with dodecylbenzenesulfonate (PPy/DBS) in trilayer arrangements with a polyvinylidene fluoride membrane as the separator. A dedicated custom-designed device was built to consistently measure the response of the membrane actuators, demonstrating significant and pattern-specific enhancements of the response in terms of displacement, exchanged charge and force.

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Electroactive Polymer Deformable Micromirrors (EAPDM) for Biomedical Optics

MRS Proceedings ◽

10.1557/proc-820-o8.12 ◽

2004 ◽

Vol 820 ◽

Author(s):

Cheng Huang ◽

Bo Bai ◽

Baojun Chu ◽

Jim Ding ◽

Q.M. Zhang

Keyword(s):

Electric Fields ◽

High Performance ◽

Electromechanical Coupling ◽

Microelectromechanical Systems ◽

Vinylidene Fluoride ◽

Low Cost ◽

Biomedical Optics ◽

Electroactive Polymer ◽

Polymer Actuator ◽

Potential Applications

AbstractElectroactive polymers (EAPs) are capable of converting energy in the form of electric charge and voltage to mechanical force and movement and vice versa. Several electroactive polymer actuator materials whose responses are controlled by external electric fields, e.g. poly(vinylidene fluoride-trifluoroethylene) based fluoroterpolymers, have generated considerable interest for use in applications such as artificial muscles, sensors, parasitic energy capture, integrated bio-microelectromechanical systems (BioMEMS) and microfluidic devices due to their high electric-field induced strain, high elastic modulus, high electromechanical coupling and high frequency operation, etc. Scaling the EAP down into microsystems is one of the promising trends of EAP actuators and sensors especially for biomedical engineering. The combination of micro-optics and integrated BioMEMS, referred to as bio-micro-opto-electromechanical systems (BioMOEMS), makes a new opportunity for innovation in the EAP field. We present an approach to the fabrication of low-cost, large-stroke deformable micromirrors based on high performance electroactive polymer film microactuator arrays. Integrated Optic-BioMEMS based on electroactive polymer deformable micromirror (EAPDM) technology provide potential applications in biomedical optics such as ophthalmology (retinal imaging and vision care) and cancer detection and treatment.

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Surface-Controlled Molecular Self-Alignment in Polymer Actuators for Flexible Microrobot Applications

Polymers ◽

10.3390/polym11040736 ◽

2019 ◽

Vol 11 (4) ◽

pp. 736 ◽

Cited By ~ 1

Author(s):

Minsu Jang ◽

Jun Sik Kim ◽

Ji-Hun Kim ◽

Do Hyun Bae ◽

Min Jun Kim ◽

...

Keyword(s):

Mechanical Properties ◽

Strain Gradient ◽

Microelectromechanical Systems ◽

Large Strain ◽

Molecular Control ◽

Polymer Actuators ◽

Maximum Angle ◽

Polymer Actuator ◽

Azobenzene Mesogens ◽

Micromechanical Systems

Polymer actuators are important components in lab-on-a-chip and micromechanical systems because of the inherent properties that result from their large and fast mechanical responses induced by molecular-level deformations (e.g., isomerization). They typically exhibit bending movements via asymmetric contraction or expansion with respect to changes in environmental conditions. To enhance the mechanical properties of actuators, a strain gradient should be introduced by regulating the molecular alignment; however, the miniaturization of polymer actuators for microscale systems has raised concerns regarding the complexity of such molecular control. Herein, a novel method for the fabrication of micro-actuators using a simple molecular self-alignment method is presented. Amphiphilic molecules that consist of azobenzene mesogens were located between the hydrophilic and hydrophobic surfaces, which resulted in a splayed alignment. Thereafter, molecular isomerization on the surface induced a large strain gradient and bending movement of the actuator under ultraviolet-light irradiation. Moreover, the microelectromechanical systems allowed for the variation of the actuator size below the micron scale. The mechanical properties of the fabricated actuators such as the bending direction, maximum angle, and response time were evaluated with respect to their thicknesses and lengths. The derivatives of the polymer actuator microstructure may contribute to the development of novel applications in the micro-robotics field.

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Back-Relaxation of Carbon-Based Ionic Electroactive Polymer Actuators

Volume 1: Development and Characterization of Multifunctional Materials; Modeling, Simulation and Control of Adaptive Systems; Structural Health Monitoring ◽

10.1115/smasis2012-8127 ◽

2012 ◽

Author(s):

Veiko Vunder ◽

Andres Punning ◽

Alvo Aabloo

Keyword(s):

Ionic Liquid ◽

Excited State ◽

Side Effect ◽

Electroactive Polymer ◽

Initial Shape ◽

Polymer Actuators ◽

Water Based ◽

Polymer Actuator ◽

Carbon Based

Back-relaxation — a phenomenon, where the ionic electro-active polymer actuator in its excited state decays back towards its initial shape — is commonly associated with the aqueous IPMC and explained with leak of water. Regardless of the absence of the fluent liquid, the dry actuators with electrodes made of carbon and ionic liquid as electrolyte, exhibit similar side effect. We show that by means of their long-term transient spatial actuation, moment of force, and back-relaxation, the behavior of the carbon-based actuators is comparable to the water-based IPMC actuators.

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