Electroactive Polymer Artificial Muscles Research Articles

Toward long and strong electroactive supercoiled polymer artificial muscles: Fabrication with constant-load springs

Toward long and strong electroactive supercoiled polymer artificial muscles: Fabrication with constant-load springs

Effect of Temperature on Electrical Resistance-Length Characteristic of Electroactive Supercoiled Polymer Artificial Muscle

Effect of Temperature on Electrical Resistance-Length Characteristic of Electroactive Supercoiled Polymer Artificial Muscle

S-Shaped Nonlinearity in Electrical Resistance of Electroactive Supercoiled Polymer Artificial Muscle

S-Shaped Nonlinearity in Electrical Resistance of Electroactive Supercoiled Polymer Artificial Muscle

4-34 人工筋肉(EPAM)の駆動性能,発電性能の評価((9)エネルギーシステム2,Session 4 新エネルギー)

4-34 人工筋肉(EPAM)の駆動性能,発電性能の評価((9)エネルギーシステム2,Session 4 新エネルギー)

Toward Energetically Autonomous Foraging Soft Robots

Abstract A significant goal of robotics is to develop autonomous machines, capable of independent and collective operation free from human assistance. To operate with complete autonomy robots must be capable of independent movement and total energy self-sufficiency. We present the design of a soft robotic mouth and artificial stomach for aquatic robots that will allow them to feed on biomatter in their surrounding environment. The robot is powered by electrical energy generated through bacterial respiration within a microbial fuel cell (MFC) stomach, and harvested using state-of-the-art voltage step-up electronics. Through innovative exploitation of compliant, biomimetic actuation, the soft robotic feeding mechanism enables the connection of multiple MFC stomachs in series configuration in an aquatic environment, previously a significant challenge. We investigate how a similar soft robotic feeding mechanism could be driven by electroactive polymer artificial muscles from the same bioenergy supply. This wo...

Ionic electroactive polymer artificial muscles in space applications

A large-scale effort was carried out to test the performance of seven types of ionic electroactive polymer (IEAP) actuators in space-hazardous environmental factors in laboratory conditions. The results substantiate that the IEAP materials are tolerant to long-term freezing and vacuum environments as well as ionizing Gamma-, X-ray, and UV radiation at the levels corresponding to low Earth orbit (LEO) conditions. The main aim of this material behaviour investigation is to understand and predict device service time for prolonged exposure to space environment.

Consistent ocean wave energy harvesting using electroactive polymer (dielectric elastomer) artificial muscle generators

An energy transduction technology that operates efficiently over a range of frequencies is important for practical energy harvesting devices such as ocean wave power generators. Dielectric elastomer is based on the change in capacitive energy of a deformable dielectric and is a candidate for such applications. A simple scale model of EPAM-based wave energy harvesting system was tested in a wave tank over a range of wave periods from 0.7 to 3s and wave heights from 2cm to 6cm. The energy output was found to be largely independent of wave period.

Artificial Muscle for Reanimation of the Paralyzed Face

Current management of permanent facial paralysis centers on nerve grafting and muscle transfer; however, limitations of those procedures call for other options. To determine the durability and biocompatibility of implanted artificial muscle in a gerbil model and the degree of inflammation and fibrosis at the host tissue–artificial muscle interface. Electroactive polymer artificial muscle (EPAM) devices engineered in medical-grade silicone were implanted subcutaneously in 13 gerbils. The implanted units were stimulated with 1 kV at 1 Hz, 24 h/d via a function generator. Electrical signal input/output was recorded up to 40 days after implantation. The animals were euthanized between 23 and 65 days after implantation, and the host tissue–implant interface was evaluated histologically. The animals tolerated implantation of the EPAM devices well, with no perioperative deaths. The muscle devices created motion for a mean of 30.3 days (range, 19-40 days), with a mean of 2.6 × 106 cycles (range, 1.6 × 106 to 3.5 × 106 cycles). Histologic examination of the explanted devices revealed the development of a minimal fibrous capsule surrounding the implants, with no evidence of bacterial infection or inflammatory infiltrate. No evidence of device compromise, corrosion, or silicone breakdown was noted. Artificial muscle implanted in this short-term animal model was safe and functional in this preliminary study. We believe that EPAM devices will be a safe and viable option for restoration of facial motions in patients with irreversible facial paralysis. Ledgerwood et al examine the durability and biocompatibility of implanted electroactive polymer artificial muscle devices in an animal model.

Biomimetic chromatophores for camouflage and soft active surfaces

Chromatophores are the pigment-containing cells in the skins of animals such as fish and cephalopods which have chromomorphic (colour-changing) and controllable goniochromic (iridescent-changing) properties. These animals control the optical properties of their skins for camouflage and, it is speculated, for communication. The ability to replicate these properties in soft artificial skin structures opens up new possibilities for active camouflage, thermal regulation and active photovoltaics. This paper presents the design and implementation of soft and compliant artificial chromatophores based on the cutaneous chromatophores in fish and cephalopods. We demonstrate artificial chromatophores that are actuated by electroactive polymer artificial muscles, mimicking the radially orientated muscles found in natural chromatophores. It is shown how bio-inspired chromomorphism may be achieved using both areal expansion of dielectric elastomer structures and by the hydrostatic translocation of pigmented fluid into an artificial dermal melanophore.

Current status and future prospects of power generators using dielectric elastomers

Electroactive polymer artificial muscle (EPAM), known collectively as dielectric elastomersin the literature, has been shown to offer unique capabilities as an actuator and is nowbeing developed for a wide variety of generator applications. EPAM has severalcharacteristics that make it potentially well suited for wave, water current, wind, humanmotion, and other environmental energy harvesting systems including a high energy densityallowing for minimal EPAM material quantities, high energy conversion efficiencyindependent of frequency of operation and non-toxic and low-cost materials notsusceptible to corrosion. Experiments have been performed on push-button andheel-mounted generator devices powered by human motion, ocean wave power harvestersmounted on buoys and water turbines. While the power output levels of suchdemonstration devices is small, the performance of these devices has supportedthe potential benefits of EPAM. For example, an electrical energy conversionefficiency of over 70% was achieved with small wave heights. The ability of EPAM toproduce hydrogen fuel for energy storage was also demonstrated. Because theenergy conversion principle of EPAM is capacitive in nature, the performanceis largely independent of size and it should eventually be possible to scale upEPAM generators to the megawatt level to address a variety of electrical powerneeds.

Electrically Tunable Polymer DFB Laser

Soft optical components based on flexible polymers or fluids can be coupled to electroactive polymer artificial muscles for monolithically integrated optical elements with voltage controlled properties. A flexible polymer distributed feedback (DFB) dye laser is combined with an electroactive dielectric elastomer actuator to afford continuous voltage-controlled wavelength shift.

Dielectric-elastomer actuators deliver clean energy

Last year marked the 10th anniversary of the Stanford Research Institute’s landmark Science paper on deformable capacitors based on elastomeric insulators with highly compliant electrodes.1 It showed that attractive electrostatic forces between positive and negative charges on compliant electrodes lead to high-speed, giant-strain, electrically controlled actuators, which have now exceeded the performance of natural muscles in terms of strain, stress, and elastic-energy density. The perspectives of the field are discussed in a recent Science article,2 showing that such dielectric-elastomer actuators (or electroactive-polymer artificial muscle) have become areas of both intense academic research and industrial development. Electrically controlled optical lenses and phase gratings are already on the market,3 while a first mass-market application has been announced for mobile phones, providing users with vibrotactile feedback.4 Key factors promoting the success of the technology are the simple physics behind the actuation (attractive electrostatic forces acting on soft, deformable dielectrics) and its cost-effective implementation with inexpensive materials. The idea that a solid material deforms when stimulated by electricity originated in the late 18th Century, as documented in a letter by Alessandro Volta discussing observations of Felice Fontana on volume changes in electrified Leyden jars, the first electrical capacitors.2 In the late 19th Century, Wilhelm Conrad Rontgen designed an experiment, which is seen today as a beautiful description of the dielectric-elastomer-actuation principle.2 A rubber strip, when electrified by a corona discharge (which sprays opposite electrical charges on either side of the strip), shrinks in thickness and increases in length. Figure 1 shows a sketch of the experiment and a demonstration using simple household materials. We replicated Rontgen’s experiment with modern materials,5 showing that such charge-controlled actuation overcomes the electromechanical pull-in effect, i.e., the mechanical collapse of Figure 1. (top) Dielectric-elastomer-actuation principle anticipated by Rontgen in 1880 and (bottom) demonstration of the elongation of a stretched rubber strip after corona charging. HV: High voltage.

Force Requirements for Artificial Muscle to Create an Eyelid Blink With Eyelid Sling

To determine the force requirements, optimal vector, and appropriate materials of a novel eyelid sling device that will be used to rehabilitate eyelid closure (blink) in congenital or acquired permanent facial paralysis with an artificial muscle. The force required to close the eyelids in human cadavers (n = 6) were measured using a load cell system. The eyelid sling using either expanded polytetrafluoroethylene (ePTFE) or temporalis muscle fascia was implanted. The ideal vector of force and placement within the eyelid for a natural eyelid closure were compared. The eyelid sling concept was successful at creating eyelid closure in a cadaver model using an upper eyelid sling attached to the distal tarsal plate. Less force was necessary to create eyelid closure using a temporalis muscle fascia sling (627 ± 128 mN) than for the ePTFE eyelid sling (1347 ± 318 mN). The force and stroke required to close an eyelid with the eyelid sling are well within the attainable range of the electroactive polymer artificial muscle (EPAM). This may allow the creation of a realistic and functional eyelid blink that is symmetric and synchronous with the contralateral, normally functioning blink. Future aims include consideration of different sling materials and development of both the EPAM device and an articulation between the EPAM and sling. The biocompatibility and durability studies of EPAM in a gerbil model are under way. The successful application of artificial muscle technology to create an eyelid blink would be the first of many potential applications.

Force Requirements for Artificial Muscle to Create an Eyelid Blink With Eyelid Sling

To determine the force requirements, optimal vector, and appropriate materials of a novel eyelid sling device that will be used to rehabilitate eyelid closure (blink) in congenital or acquired permanent facial paralysis with an artificial muscle. The force required to close the eyelids in human cadavers (n = 6) were measured using a load cell system. The eyelid sling using either expanded polytetrafluoroethylene (ePTFE) or temporalis muscle fascia was implanted. The ideal vector of force and placement within the eyelid for a natural eyelid closure were compared. The eyelid sling concept was successful at creating eyelid closure in a cadaver model using an upper eyelid sling attached to the distal tarsal plate. Less force was necessary to create eyelid closure using a temporalis muscle fascia sling (627 +/- 128 mN) than for the ePTFE eyelid sling (1347 +/- 318 mN). The force and stroke required to close an eyelid with the eyelid sling are well within the attainable range of the electroactive polymer artificial muscle (EPAM). This may allow the creation of a realistic and functional eyelid blink that is symmetric and synchronous with the contralateral, normally functioning blink. Future aims include consideration of different sling materials and development of both the EPAM device and an articulation between the EPAM and sling. The biocompatibility and durability studies of EPAM in a gerbil model are under way. The successful application of artificial muscle technology to create an eyelid blink would be the first of many potential applications.

A thin membrane artificial muscle rotary motor

Desirable rotary motor attributes for robotics include the ability to develop high torque in a low mass body and to generate peak power at low rotational speeds. Electro-active polymer artificial muscles offer promise as actuator elements for robotic motors. A promising artificial muscle technology for use as a driving mechanism for rotary motion is the dielectric elastomer actuator (DEA). We present a membrane DEA motor in which phased actuation of electroded sectors of the motor membrane impart orbital motion to a central drive that turns a rotor. The motor is inherently scalable, flexible, flat, silent in operation, amenable to deposition-based manufacturing approaches, and uses relatively inexpensive materials. As a membrane it can also form part of the skin of a robot.

Restoration of Eyelid Closure in Facial Paralysis Using Artificial Muscle: Preliminary Cadaveric Analysis

Electroactive polymer artificial muscle is an emerging technology that has the potential to be used in rehabilitating facial movement in patients with paralysis. These electroactive polymers act like human muscles by expanding and contracting based on variable voltage input levels. The authors seek to establish a reproducible eyelid blink with artificial muscle. The aim of this proof of concept study is to determine whether eyelid closure can be created with a novel eyelid sling model. A human cadaver study was performed. With use of four cadaver heads, an extended upper and lower blepharoplasty incision was used to secure an upper and lower expanded polytetrafluoroethylene implant in the medial orbital wall and tarsal plates. The slings were passed through a hole drilled in the lateral orbital wall or around a titanium screw. Lateral pull on the sling created eyelid closure, and the necessary distance of pull was measured. The eyelid sling mechanism functioned to achieve complete eyelid closure. Less tension was required for eyelid closure when the sling was placed in both eyelids (3 mm of pull instead of 6 mm). The application of artificial muscle to a range of problems that affect both patient morbidity and quality of life is promising. Eyelid closure was created in a cadaver model using a novel sling, but future studies will need to address the feasibility of a prototype artificial muscle eyelid device in humans.

Robots will be of service with muscles, not motors

PurposeAims to project how electroactive polymer will replace conventional electromagnetic motor driven solutions for service and industrial robots.Design/methodology/approachPresents the ability of electro active polymer to provide higher power density for robot actuation over conventional approaches. Laboratory tests by DARPA compared electroactive polymer with conventional electromagnetic methodologies as well as shape memory alloy and piezo solutions.FindingsTests by DARPA and SRI International showed significant power density advantages for electroactive polymer artificial muscles (EPAM). Robot prototypes and well as early commercial prototypes developed by Artificial Muscle, Inc. in pumps, valves, and actuators prove superior performance over other actuation solutions.Originality/valueIntroduces a new low cost, low power consumption, light weight, and silent method for actuation for robots and other motion control devices.

Medical Applications of New Electroactive Polymer Artificial Muscles

Medical Applications of New Electroactive Polymer Artificial Muscles

Ionomeric Electroactive Polymer Artificial Muscle for Naval Applications

Specialized propulsors for naval applications have numerous opportunities in terms of research, design, and fabrication of an appropriate propulsor. One of the most important components of any propulsor is the actuator that provides the mode of locomotion. ionomeric electroactive polymer may offer an attractive solution for locomotion of small propulsors. A common ionomeric electroactive polymer, ionic polymer-metal composites (IPMCs) give large true bending deformations under low driving voltages, operate in aqueous environments, are capable of transduction, and are relatively well understood. IPMC fabrication and operation are presented to further elucidate the use of the material for a propulsor. Various materials, including IPMCs, are investigated and a simplified propulsor model is explored.

Ultra-High Strain Response of Elastomeric Polymer Dielectrics

AbstractThe strain response of dielectric elastomers sandwiched between compliant electrodes was studied. These electroactive polymer artificial muscle (EPAM) materials show excellent overall performance and appear more attractive than many competing actuator technologies. Based on the available data, the actuation mechanism is due to the free charge interaction of the compliant electrodes, enhanced by the dielectric properties of the elastomer (Maxwell stress). Strains over 200%, actuation pressures up to 8 MPa, and energy densities up to 3.4 J/cm3have been demonstrated with silicone rubber and acrylic elastomers. Response time is rapid, and the potential efficiency is high. The fabrication of EPAM actuators can be simple and low cost. A wide range of small devices have been made, to demonstrate the potential of the technology and reveal more about performance and fabrication issues. These devices include bending beam actuators for scanners and clamps, diaphragm actuators for pumps and valves, stretched-film actuators for electro-optics, and bow actuators for muscle-like actuators for small robots and other micro machines.