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In this paper, we propose a soft vibrotactile actuator made by mixing silicon dioxide \mathrm(SiO2) nanoparticles and plasticized PVC gel. The effect of the silicon dioxide nanoparticles in the plasticized PVC gel for the haptic performance is investigated in terms of electric, dielectric, and mechanical properties. Furthermore, eight soft vibrotactile actuators are prepared as a function of the \mathrmSiO2 content. Experiments are conducted to examine the haptic performance of the prepared eight soft vibrotactile actuators and to find the best weight ratio of the plasticized PVC gel to the \mathrmSiO2 nanoparticles. The experiments should show that the plasticized PVC gel with silicon dioxide nanoparticles improves the haptic performance of the plasticized PVC gel-based vibrotactile actuator, and the proposed vibrotactile actuator can create a variety of haptic sensations in a wide frequency range. [ABSTRACT FROM PUBLISHER]

This paper reports soft actuator based tactile stimulation interfaces applicable to wearable devices. The soft actuator is prepared by multi-layered accumulation of thin electro-active polymer (EAP) films. The multi-layered actuator is designed to produce electrically-induced convex protrusive deformation, which can be dynamically programmable for wide range of tactile stimuli. The maximum vertical protrusion is ${{650}}\,\mu {\mathrm{m}}$ and the output force is up to 255 mN. The soft actuators are embedded into the fingertip part of a glove and front part of a forearm band, respectively. We have conducted two kinds of experiments with 15 subjects. Perceived magnitudes of actuator's protrusion and vibrotactile intensity were measured with frequency of 1 Hz and 191 Hz, respectively. Analysis of the user tests shows participants perceive variation of protrusion height at the finger pad and modulation of vibration intensity through the proposed soft actuator based tactile interface. [ABSTRACT FROM PUBLISHER]

We report a flexible visuo-haptic display that allows for interactive haptic feedback on the visual display. The visuo-haptic display is fabricated by integrating a dielectric elastomer (DE) based thin film actuator array into a flexible display and pressure sensors. The DE actuator array consists of nine active cells, which generate thickness-mode deformation in response to voltage signal. The flexible display presents images of the aligned three alphabet characters at each section in 3 × 3 matrix during light propagation via optical multiwaveguide. The pressure sensors are placed on the bottom of the DE actuator array for haptic feedback. The performance of the DE actuators is proved to be capable of realizing sufficient vibro-tactile sensation in the perceivable range of human touch sense. The integrated system enables the visual display to provide interactive haptic feedback such as key pressing, contact vibration sensations, etc., in accordance with user input. [ABSTRACT FROM PUBLISHER]

We report a film-type haptic actuator made with two cellulose acetate active membranes and an air gap. Two different configurations of the actuators, double cellulose acetate membranes and single cellulose acetate membrane, are investigated. Due to the intensified electrostatic attraction force between chargeable cellulose acetate membranes, the double cellulose acetate membrane case shows over 300% displacement enhancement. Under a bias electric field, the displacement can be 200% improved comparing with no bias case. When the actuator performance of the cellulose acetate membrane is compared with polyethylene terephthalate and polyvinyl chloride membranes, the cellulose acetate membrane shows superior displacement output due to its high dielectric property. The cellulose acetate double membrane actuator has a great potential as kinesthetic actuator of haptic devices. [ABSTRACT FROM AUTHOR]

Abstract: Covalently bonded multi-walled carbon nanotubes (MWNTs) to cellulose were used to fabricate electro-active paper (EAPap) and its mechanical properties as well as actuator performance were investigated. A cellulose solution was prepared by dissolving cotton pulp in LiCl/N,N-dimethylacetamide (DMAc) solution. MWNTs were covalently bonded to cellulose by reacting MWNTs-imidazolides with cellulose solution. Using this, MWNTs/cellulose (M/C) EAPap was fabricated with different weight percents of MWNTs. This EAPap was analyzed by Fourier-transform IR, X-ray diffraction and X-ray photoelectron spectroscopy and their Young''s modulus was measured. The actuator performance of M/C EAPap was evaluated in terms of bending displacement, resonance frequency and electrical power consumption depending on the weight percent of MWNTs and humidity levels. Due to the presence of covalent bonds between MWNTs and cellulose, the Young''s modulus of M/C EAPap was remarkably enhanced more than the MWNTs blended EAPap. The enhanced Young''s modulus was strongly associated with the crystallinity change of cellulose. The actuator performance of M/C EAPap was improved also. More explanation about the characteristics, actuation principle and actuator performance of M/C EAPap actuator is addressed. [Copyright &y& Elsevier]

Abstract: Functionalized multi-walled carbon nanotubes (F-MWNTs) were blended with cellulose solution to fabricate F-MWNTs/cellulose electro-active paper (EAPap) actuators. Cellulose was dissolved in LiCl/N,N-dimethylacetamide (DMAc) solution by solvent exchange process and blended with F-MWNTs to make F-MWNTs/cellulose EAPap actuators. Their characteristics were investigated by taking X-ray diffractometer (XRD), SEM, Young''s modulus measurement and water retention measurement. Actuator performance of F-MWNT/cellulose EAPap was evaluated in terms of bending displacement, resonance frequency, output force and electrical power consumption. A large bending displacement of 4.5mm and improved output force of the actuator were obtained. The actuation principle of cellulose EAPap was more likely based on ion migration effect, especially in humid condition. More explanation about the characteristics, actuation principle and performance of actuator is introduced. [Copyright &y& Elsevier]

The article discusses research done on the impact of lithium ions (Li+) on the actuation, properties, and structure of cellulose electro-active paper (EAPap) actuator. The researchers dissolved cellulose fibers using a solution of lithium chloride in N,N-dimethylacetamide. Results indicated the significance of the elimination of ions to increase the piezoelectric impact in EAPap.

Abstract: This paper investigates the performance of electro-active paper (EAPap) actuators with thickness variation. EAPap made with cellulose paper, is attractive for biomimetic actuators due to its characteristics in terms of lightweight, biodegradable, dry condition, large displacement output, low actuation voltage and low power consumption. EAPap actuators exhibit a bending deformation in the presence of electric field. However, the performance is sensitive to the thickness of the EAPap material because the thickness is associated with the bending stiffness that strongly affects the bending deformation and the force output of the actuator. Thus, the performance of EAPap actuators that have three different samples of 20, 30, and 40μm thicknesses is tested in terms of tip displacement, blocked force, electrical power consumption, and the efficiency. The sample preparation and the test methods are addressed. The resonance frequency and the bending stiffness are associated with the thickness of the EAPap actuator, and there is an optimum thickness for the best performance of the EAPap actuators. The mechanical output power and the efficiency at an optimal thickness are drastically improved comparing with the previous thickness case. [Copyright &y& Elsevier]

In this paper, we proposed a novel light-driven polymer actuator that could produce remotely controllable tensile stroke in response to near infrared (NIR) light. The light-driven polymer actuator was composed of a twisted and coiled nylon-6 fiber (TCN) and a thin poly(3,4-ethylenedioxythiophene) doped with p-toluenesulfonate (PEDOT-Tos) layer. By adopting dip-coating methodology with thermal polymerization process, we constructed a thin and uniform PEDOT-Tos layer on the surface of the three-dimensional TCN structure. Thanks to the PEDOT-Tos layer with excellent NIR light absorption characteristic, the NIR light illumination via a small LEDs array allowed the multiple PEDOT-Tos coated TCN actuators to be photo-thermally heated to a fairly consistent temperature and to simultaneously produce a contractile strain that could be modulated as high as 8.7% with light power. The actuation performance was reversible without any significant hysteresis and highly durable during 3000 cyclic operations via repetitive control of the LEDs. Together with its simple structure and facile fabrication, the light-driven actuator can lead to technical advances in artificial muscles due to its attractive benefits from remote controllability without complex coupled instruments and electromagnetic interference. [ABSTRACT FROM AUTHOR]

We propose a monolithic focus-tunable lens structure based on the dielectric-elastomer actuator (DEA) technology. In our focus-tunable lens, a soft lens and radial in-plane actuator mimicking the ocular focal-tuning mechanism are constructed in a single body of an optimized dielectric-elastomer film. We provide device fabrication methods including elastomer synthesis, structure formation, and packaging process steps. Performance test measurements show 93% focal tunability and 7 ms response time under static and dynamic electrical driving conditions, respectively. These performance characteristics are substantially enhanced from the previous polylithic DEA tunable lens by a factor 1.4 for the focal tunability and a factor 9.4 for the dynamic tuning-speed limit. Therefore, we obtain greatly enhanced focal tuning control in a remarkably simple and compact device structure. [ABSTRACT FROM AUTHOR]

We demonstrate a robust flexible tactile actuator that is capable of working under high external pressures. The tactile actuator is based on a pyramidal microstructured dielectric elastomer layer inducing variation in both mechanical and dielectric properties. The vibrational performance of the actuator can be modulated by changing the geometric parameter of the microstructures. We evaluated the performance of the actuator under high-pressure loads up to 25 kPa, which is over the typical range of pressure applied when humans touch or manipulate objects. Due to the benefit of nonlinearity of the pyramidal structure, the actuator could maintain high mechanical output under various external pressures in the frequency range of 100–200 Hz, which is the most sensitive to vibration acceleration for human finger pads. The responses are not only fast, reversible, and highly durable under consecutive cyclic operations, but also large enough to impart perceivable vibrations for haptic feedback on practical wearable device applications. [ABSTRACT FROM AUTHOR]

Abstract: This paper presents a blocked force measurement of electro-active paper (EAPap) with a simple configuration and high accuracy. Blocked force is a force at the tip of a bending actuator when the tip is fixed. A micro-balance with a fixture is used to measure the blocked force of EAPap bending actuator. The measurement is conducted with dc electric fields. A theoretical blocked force is calculated by using the cantilever beam model, and the measured blocked force is compared with the calculated result. Comparing the measured blocked force with the calculated result shows a good agreement. This force measurement method is simple and accurate, and can be applied for measuring blocked forces of EAP actuators. [Copyright &y& Elsevier]