Most of the current market demand is for EAP (Electro Active Polymers) power suits, EAP motors, EAP muscles for robots, and systems that drive them in reverse to generate electricity efficiently. We believe that Dielectric Elastomer (DE) transducers are the most suitable for those purposes. To meet these demands, the elasticity of the elastomer is extremely important. We conducted SS (strain stress) curves and viscoelasticity tests on several DE materials (including HNBR: Hydrogenated nitrile rubber) to examine DE’s elongations and their relationships. We discuss important factors (such as cross-linking agents and double bond cleavage) in this paper, based on the research results. In addition, recent attempts have been made to use new carbon foam materials such as single-wall carbon nanotubes (SWCNTs) and multi-wall nanotubes (MWCNTs) as electrodes for DEs. These electrodes could bring a higher performance for DEs. Those possibilities are also discussed in the paper.
A CNT has a very low light density, about half that of aluminum, but its strength is about 20 times that of steel. Its current density resistance is more than 1000 times that of copper, and it also has higher thermal conductivity than copper. Although it is an excellent material that can be expected to be used in various fields, using it effectively proves to be a difficult task. We have succeeded in developing a flexible and stretchable CNT paint with the aim of applying this excellent material to DEA electrodes. This CNT paint can be easily applied to various materials by using a spray or other methods and since it can expand and contract, it can be applied to easily deformable materials such as polymers, wood, paper, and resin. It is possible to add the characteristics of CNTs to various materials. One of the characteristics of CNTs that has been attracting attention in recent years is the radio wave absorption effect. As the understanding of this process is expected to grow ever more important, the purpose of this paper is to verify the effect of radio wave absorption, one of the methods of utilizing CNTs, in the range from single to high double digit GHz bands.
By using a dielectric elastomer (DE) sensor and observing the change in capacitance due to the amount of water, the amount of change in water can be measured more accurately. Further, since it is flexible, it offers excellent wearability as a sensor attached to the body, or is excellent comfort as an unobtrusive sensor attached to a chair. Also, since this sensor does not use metal leads, there is no risk of rust or metal allergies. The principle is simple; the frequency changes due to the change in the capacitance of DE (capacitor), making it is possible to measure moisture by the change. An inexpensive elastomer can be used for the dielectric, and carbon black, CNT, or the like can be used for the stretchable electrode.
A DE capable of the high speed and high output required for driving robots and automobiles is still under study. Chiba et al succeeded in raising and lowering a 4kg weight by about 1mm at a speed of 97msec using a total DE weight of 0.98g last year. The DEA used a VHB4910 and SWCNTs. For the above purposes mentioned above, however, the current weight able to lifted is insufficient. We examined various elastomers (including materials newly developed) and various electrode materials, and we succeeded in lifting a weight of 8 kg quickly. We also considered the potential of this DEA as a drive source for electric vehicles and a potential for power generation from the vehicle’s movement.
KEYWORDS: Dielectrics, Device simulation, Power supplies, Capacitance, Field effect transistors, Chemical elements, Wind energy, Capacitors, Switching, Renewable energy
Dielectric elastomer generation is a power generation method that converts various mechanical energies into electric energy by using a dielectric elastomer. Dielectric elastomer generation can harvest electric energy from renewable energy sources such as sea wave power, hydraulic power (Karman vortex), and wind power. Practical application of dielectric elastomer generation faces various issues; however, this paper will focus on an electrical problem of a dielectric elastomer generation circuit. The dielectric elastomer generation circuit needs an external power supply to charge the dielectric elastomer before starting the electric generation. Additionally, the dielectric elastomer generation circuit requires a high DC voltage. In this paper, we propose a self-excited dielectric elastomer generation circuit using piezoelectric elements. The proposed circuit consists of piezoelectric elements, the Cockcroft-Walton circuit, the dielectric elastomer, and the ringing choke converter. In the proposed circuit, the piezoelectric element is vibrated to generate a voltage, and the generated voltage is boosted to a high voltage value for charging the dielectric elastomer by the Cockcroft-Walton circuit. After the dielectric elastomer generation is completed, the ringing choke converter circuit steps down the generated voltage to a predetermined value, and the generated power is the output to a load. Furthermore, operations of the circuit are confirmed by the simulation and experimental results. The experimental results are obtained by using a test bench. The test bench uses a piston machine driven by a DC motor for the purpose of stretching and shrinking the dielectric elastomer.
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