A CNT spray can impart conductivity to various materials through simple application alone, not re... more A CNT spray can impart conductivity to various materials through simple application alone, not requiring any special equipment or techniques. The sprayed CNTs are flexible after drying and remain conductive and connected even when bent or stretched. In addition, because of its excellent adhesiveness, it does not easily peel off or scatter after drying. It is very easy to use, able to be applied with a special CNT paint spray. Expensive dispersing equipment and special coating equipment are not required, doing away with troublesome dispersion work. With a CNT sprayer and dielectric elastomer, it is possible to make a DE easily, which can further promote DE research and trial production. It is possible to change the content of CNTs according to the purpose. By simply applying CNT spray, the following can be easily achieved: DE electrodes, wiring of electronic circuits that require flexibility, mounting of electronic components on flexible PCBs, and rubber that requires flexibility. It is also possible to easily add conductivity to a sponge.
Electroactive polymer transducers have many features that are desirable for various devices. An e... more Electroactive polymer transducers have many features that are desirable for various devices. An especially attractive type of electroactive polymer is dielectric elastomer (DE). Our recent progress is a DE actuator having only 0.1 g of DE that lifted a weight of 2 kg using carbon system electrodes. We also developed a ribbon form DE actuator having a sensor function that can be used to measure force, or pressure, as well as motion at the same time. This actuator can assist human and robot motions. At the same time, it can work as a motion feedback sensor. We hope that it may be useful for smart rehabilitation equipment for hands, legs, and fingers. DE has also been shown to operate in reverse as a generator. Experiments have been performed on portable DE generators/wearable generators powered by human motion, ocean wave power harvesters mounted on buoys, solar heat generators, and water turbines. While the power output levels of such demonstration devices is small, the performance o...
Human-Robot Interaction - Perspectives and Applications [Working Title], 2022
Most of the conventional sensors used for measuring deformation, pressure, etc., use metal, ceram... more Most of the conventional sensors used for measuring deformation, pressure, etc., use metal, ceramics, piezo, or the like. Many of them are very rigid, and when the object is deformed or when the pressure on the object changes currently, it is necessary to arrange a large number of sensors with different conditions side by side. However, it is still difficult to measure all changes over time. With the newly developed dielectric elastomer sensor, even a very thin (0.1–0.2 mm) elastomer thickness could be deformed in difficult environments (e.g., places with large temperature changes or large vibrations), and it would be possible to measure any pressure changes due to its deformation. By applying this sensor, it can be used as a position sensor (including a three-dimensional sensor) or an acceleration sensor, so that it could be applied to the control of the arms and legs of a robot, smart shoes, and the like.
Energy generation using dielectric elastomers (DE) has received a great deal of attention due to ... more Energy generation using dielectric elastomers (DE) has received a great deal of attention due to their light weight, low cost, and high efficiency. This method is an environmentally friendly system that generates electricity without emitting carbon dioxide and without using rare earths, and can contribute to the reduction of global warming. However, this DE system is expected to be used for wearables, such as shoe power generation, because it is not yet possible to make an energy generation element of a very large size. The problem is that this small DE generator can only generate a small amount of energy at one time. Therefore, in order to increase energy generation efficiency, it is necessary to use a material with higher conductivity for the DE electrode. Moreover, since DE energy generation is output at a high voltage, a circuit capable of stepping down with high efficiency is required in order to use this power for ordinary electric appliances. In addition to this, a circuit th...
Dielectric Elastomers (DE) can be excellent transducers for actuators, sensors and generators. Th... more Dielectric Elastomers (DE) can be excellent transducers for actuators, sensors and generators. Therefore, a lot of research on DE applications has been done. Actuators, sensors and generators for small devices will be coming to the market very soon. However, much of the market demand is for heavier applications such as DE power suits, DE motors, DE muscles for robots, and larger DE power systems. In order to meet such requirements, attempts have recently been made to use new carbon foam materials such as SWCNTs or MWCNTs as electrodes for DEs. As a result, using SWCNT electrodes, a DE actuator with only 0.96 g of DE material can easily lift a 41N weight. Furthermore, a transparent diaphragm actuator can be manufactured by using super purified SWCNTs. This paper shows that the performance of DE varies significantly depending on the type of electrode materials used. When carbon black, MWCNT and SWCNT were used as electrode materials for DE, we investigated how much weight could be lif...
Electro active polymers (EAPs) are used for actuators that can electrically control their motions... more Electro active polymers (EAPs) are used for actuators that can electrically control their motions to resemble those of actual muscles. Thus, they are called artificial muscles. In addition, since EAPs are often made of flexible materials, they have also come to be called “soft actuators” in recent years. There are many types of EAPs such as dielectric elastomers (Perline & Chiba, 1992a), ionic polymer-metal composites (Oguro et al., 1999), electroconductive Polymers (Otero & Sansinera, 1998), and ion polymer gels (Osada et al., 1992b). Figure 1 shows typical EAPs.
Electroactive Polymer Actuators and Devices (EAPAD) XXII
The conductivity of DE can be further improved by using single-wall CNT (SWCNT), which has higher... more The conductivity of DE can be further improved by using single-wall CNT (SWCNT), which has higher conductivity than carbon black. Electrodes using SWCNTs can be easily created by packing the CNTs in a spray can. This method was most recently developed by Zeon Corporation under the direction of Chiba et al. In the CNT dispersion, the CNT and 2% by weight sodium cholate were first added to the dispersion medium, and then dispersed using an ultrasonic homogenizer. When DE was produced using this CNT spray electrode on 3M acrylic, it was 2.2 times better than DE produced using the carbon.
An important issue concerning the safe use of hydrogen powered fuel cell vehicles is the possibil... more An important issue concerning the safe use of hydrogen powered fuel cell vehicles is the possibility of accidents occurring within a tunnel. Such accidents might result in the release and deflagration of hydrogen from a vehicle’s storage tanks or possibly from a hydrogen transport vehicle such as a tube trailer or tank car on a freight train. A total of ten experiments have been performed to examine the effects of confined deflagrations that could occur after a release of hydrogen in a tunnel. Release rates were scaled to match possible leak scenarios from fuel cell vehicles and hydrogen transports. Possible enhancement of the deflagration due to obstacles in the tunnel was studied by performing experiments with scale model buses in the tunnel. A system of evacuated sampling bottles was used to measure hydrogen concentration throughout the tunnel prior to ignition, and at various times during the release. All releases produced lean hydrogen concentrations. The releases that were ign...
Power generation using dielectric elastomer (DE) artificial muscle is attracting attention becaus... more Power generation using dielectric elastomer (DE) artificial muscle is attracting attention because of its light weight, low cost, and high-efficiency. Since this method is a system that produces electricity without emitting carbon dioxide nor using rare earths, it would contribute to the goal of environmental sustainability. In this paper, the background of DEs, the associated high efficiency wave energy generation (WEG) systems that we developed using DEs, as well as the latest development of its material are summarized. By covering both the challenges and achievements, this paper discusses the opportunities to build the foundation of an energy recycling society through the usage of these WEGs. To make these possibilities commercially successful, the advantages of DEs need to be integrated with traditional technologies. To achieve this, the method of using DEs alone and a system used in combination with an oscillating water column were also considered. Finally, the current status a...
Using a sample coated with three types of carbon-based paints, namely single-wall carbon nanotube... more Using a sample coated with three types of carbon-based paints, namely single-wall carbon nanotube (SWCNTs), carbon black, and graphite, the amount of radio wave absorption for each was measured. SWCNTs proved to have the superior radio wave absorption effect in the millimeter band. Considering the change in the amount of radio wave absorption depending on the coating amount, three different coating thicknesses were prepared for each test material. The measurement frequency was set to two frequency bands of 28 GHz and 75 GHz, and the measurement method was carried out based on Japanese Industrial Standard (JIS) R1679 “Radio wave absorption characteristic measurement method in the millimeter wave band of the radio wave absorber.” As for the amount of radio wave absorption in the 28 GHz band, a maximum amount of radio wave absorption of about 6 dB was obtained when 35 m of CNT spray paint was applied. It was confirmed that the carbon black paint came to about 60% that of the SWCNT, and...
A Mars airplane has been in development. This airplane requires lightweight and powerful actuator... more A Mars airplane has been in development. This airplane requires lightweight and powerful actuators to fly in the rare Martian atmosphere. A dielectric elastomer actuator (DEA) is a possible candidate for the actuator controlling the airplane since it has high power, and high efficiency. A structural model of a wing having a control surface, a DEA, and a linkage was built and a wind tunnel test of a control surface actuation using a DE actuator was carried out. It is feasible to use the DEA for controlling the Mars airplane under wind speeds of 65m/s in the Martian atmosphere.
Dielectric elastomer generation is a power generation method that converts various mechanical ene... more 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...
A CNT spray can impart conductivity to various materials through simple application alone, not re... more A CNT spray can impart conductivity to various materials through simple application alone, not requiring any special equipment or techniques. The sprayed CNTs are flexible after drying and remain conductive and connected even when bent or stretched. In addition, because of its excellent adhesiveness, it does not easily peel off or scatter after drying. It is very easy to use, able to be applied with a special CNT paint spray. Expensive dispersing equipment and special coating equipment are not required, doing away with troublesome dispersion work. With a CNT sprayer and dielectric elastomer, it is possible to make a DE easily, which can further promote DE research and trial production. It is possible to change the content of CNTs according to the purpose. By simply applying CNT spray, the following can be easily achieved: DE electrodes, wiring of electronic circuits that require flexibility, mounting of electronic components on flexible PCBs, and rubber that requires flexibility. It is also possible to easily add conductivity to a sponge.
Electroactive polymer transducers have many features that are desirable for various devices. An e... more Electroactive polymer transducers have many features that are desirable for various devices. An especially attractive type of electroactive polymer is dielectric elastomer (DE). Our recent progress is a DE actuator having only 0.1 g of DE that lifted a weight of 2 kg using carbon system electrodes. We also developed a ribbon form DE actuator having a sensor function that can be used to measure force, or pressure, as well as motion at the same time. This actuator can assist human and robot motions. At the same time, it can work as a motion feedback sensor. We hope that it may be useful for smart rehabilitation equipment for hands, legs, and fingers. DE has also been shown to operate in reverse as a generator. Experiments have been performed on portable DE generators/wearable generators powered by human motion, ocean wave power harvesters mounted on buoys, solar heat generators, and water turbines. While the power output levels of such demonstration devices is small, the performance o...
Human-Robot Interaction - Perspectives and Applications [Working Title], 2022
Most of the conventional sensors used for measuring deformation, pressure, etc., use metal, ceram... more Most of the conventional sensors used for measuring deformation, pressure, etc., use metal, ceramics, piezo, or the like. Many of them are very rigid, and when the object is deformed or when the pressure on the object changes currently, it is necessary to arrange a large number of sensors with different conditions side by side. However, it is still difficult to measure all changes over time. With the newly developed dielectric elastomer sensor, even a very thin (0.1–0.2 mm) elastomer thickness could be deformed in difficult environments (e.g., places with large temperature changes or large vibrations), and it would be possible to measure any pressure changes due to its deformation. By applying this sensor, it can be used as a position sensor (including a three-dimensional sensor) or an acceleration sensor, so that it could be applied to the control of the arms and legs of a robot, smart shoes, and the like.
Energy generation using dielectric elastomers (DE) has received a great deal of attention due to ... more Energy generation using dielectric elastomers (DE) has received a great deal of attention due to their light weight, low cost, and high efficiency. This method is an environmentally friendly system that generates electricity without emitting carbon dioxide and without using rare earths, and can contribute to the reduction of global warming. However, this DE system is expected to be used for wearables, such as shoe power generation, because it is not yet possible to make an energy generation element of a very large size. The problem is that this small DE generator can only generate a small amount of energy at one time. Therefore, in order to increase energy generation efficiency, it is necessary to use a material with higher conductivity for the DE electrode. Moreover, since DE energy generation is output at a high voltage, a circuit capable of stepping down with high efficiency is required in order to use this power for ordinary electric appliances. In addition to this, a circuit th...
Dielectric Elastomers (DE) can be excellent transducers for actuators, sensors and generators. Th... more Dielectric Elastomers (DE) can be excellent transducers for actuators, sensors and generators. Therefore, a lot of research on DE applications has been done. Actuators, sensors and generators for small devices will be coming to the market very soon. However, much of the market demand is for heavier applications such as DE power suits, DE motors, DE muscles for robots, and larger DE power systems. In order to meet such requirements, attempts have recently been made to use new carbon foam materials such as SWCNTs or MWCNTs as electrodes for DEs. As a result, using SWCNT electrodes, a DE actuator with only 0.96 g of DE material can easily lift a 41N weight. Furthermore, a transparent diaphragm actuator can be manufactured by using super purified SWCNTs. This paper shows that the performance of DE varies significantly depending on the type of electrode materials used. When carbon black, MWCNT and SWCNT were used as electrode materials for DE, we investigated how much weight could be lif...
Electro active polymers (EAPs) are used for actuators that can electrically control their motions... more Electro active polymers (EAPs) are used for actuators that can electrically control their motions to resemble those of actual muscles. Thus, they are called artificial muscles. In addition, since EAPs are often made of flexible materials, they have also come to be called “soft actuators” in recent years. There are many types of EAPs such as dielectric elastomers (Perline & Chiba, 1992a), ionic polymer-metal composites (Oguro et al., 1999), electroconductive Polymers (Otero & Sansinera, 1998), and ion polymer gels (Osada et al., 1992b). Figure 1 shows typical EAPs.
Electroactive Polymer Actuators and Devices (EAPAD) XXII
The conductivity of DE can be further improved by using single-wall CNT (SWCNT), which has higher... more The conductivity of DE can be further improved by using single-wall CNT (SWCNT), which has higher conductivity than carbon black. Electrodes using SWCNTs can be easily created by packing the CNTs in a spray can. This method was most recently developed by Zeon Corporation under the direction of Chiba et al. In the CNT dispersion, the CNT and 2% by weight sodium cholate were first added to the dispersion medium, and then dispersed using an ultrasonic homogenizer. When DE was produced using this CNT spray electrode on 3M acrylic, it was 2.2 times better than DE produced using the carbon.
An important issue concerning the safe use of hydrogen powered fuel cell vehicles is the possibil... more An important issue concerning the safe use of hydrogen powered fuel cell vehicles is the possibility of accidents occurring within a tunnel. Such accidents might result in the release and deflagration of hydrogen from a vehicle’s storage tanks or possibly from a hydrogen transport vehicle such as a tube trailer or tank car on a freight train. A total of ten experiments have been performed to examine the effects of confined deflagrations that could occur after a release of hydrogen in a tunnel. Release rates were scaled to match possible leak scenarios from fuel cell vehicles and hydrogen transports. Possible enhancement of the deflagration due to obstacles in the tunnel was studied by performing experiments with scale model buses in the tunnel. A system of evacuated sampling bottles was used to measure hydrogen concentration throughout the tunnel prior to ignition, and at various times during the release. All releases produced lean hydrogen concentrations. The releases that were ign...
Power generation using dielectric elastomer (DE) artificial muscle is attracting attention becaus... more Power generation using dielectric elastomer (DE) artificial muscle is attracting attention because of its light weight, low cost, and high-efficiency. Since this method is a system that produces electricity without emitting carbon dioxide nor using rare earths, it would contribute to the goal of environmental sustainability. In this paper, the background of DEs, the associated high efficiency wave energy generation (WEG) systems that we developed using DEs, as well as the latest development of its material are summarized. By covering both the challenges and achievements, this paper discusses the opportunities to build the foundation of an energy recycling society through the usage of these WEGs. To make these possibilities commercially successful, the advantages of DEs need to be integrated with traditional technologies. To achieve this, the method of using DEs alone and a system used in combination with an oscillating water column were also considered. Finally, the current status a...
Using a sample coated with three types of carbon-based paints, namely single-wall carbon nanotube... more Using a sample coated with three types of carbon-based paints, namely single-wall carbon nanotube (SWCNTs), carbon black, and graphite, the amount of radio wave absorption for each was measured. SWCNTs proved to have the superior radio wave absorption effect in the millimeter band. Considering the change in the amount of radio wave absorption depending on the coating amount, three different coating thicknesses were prepared for each test material. The measurement frequency was set to two frequency bands of 28 GHz and 75 GHz, and the measurement method was carried out based on Japanese Industrial Standard (JIS) R1679 “Radio wave absorption characteristic measurement method in the millimeter wave band of the radio wave absorber.” As for the amount of radio wave absorption in the 28 GHz band, a maximum amount of radio wave absorption of about 6 dB was obtained when 35 m of CNT spray paint was applied. It was confirmed that the carbon black paint came to about 60% that of the SWCNT, and...
A Mars airplane has been in development. This airplane requires lightweight and powerful actuator... more A Mars airplane has been in development. This airplane requires lightweight and powerful actuators to fly in the rare Martian atmosphere. A dielectric elastomer actuator (DEA) is a possible candidate for the actuator controlling the airplane since it has high power, and high efficiency. A structural model of a wing having a control surface, a DEA, and a linkage was built and a wind tunnel test of a control surface actuation using a DE actuator was carried out. It is feasible to use the DEA for controlling the Mars airplane under wind speeds of 65m/s in the Martian atmosphere.
Dielectric elastomer generation is a power generation method that converts various mechanical ene... more 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...
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