Papers by Keyword: Electro Active Polymer

Abstract: Transparent conducting Al doped ZnO films have been deposited by dc magnetron sputtering on glass and polymer substrates at room temperature. Depositions have been carried out from an AZOY (contains a small amount of Y2O3 in addition to Al2O3 and ZnO) target under different conditions such as working pressure, substrate bias voltage and oxygen flow rate. The crystallinity of the Al doped ZnO films has been improved by using low-energy-ion bombardment. Likewise, the use of either the rotation or the static mode of the substrate during deposition influences the crystallinity and therefore the optical parameters and the electrical resistance of the films. Increasing the thickness of the films reduces the threshold strain at which the films can be deformed without provoking significant changes on their electrical properties.

Abstract: The robot industry of the 21st century is focused on humanoid robot. It has more intelligence and is able to move dexterously like a biological organ than existing sequence robot. The key technology of this robot is the design of the actuator. To realize the anthropomorphic motion, artificial muscles, such as shape memory alloy and electro active polymer are used. The SMA actuator has good power density and simple structure, but the control scheme of the actuator is difficult. The electro active polymer has good elasticity, but it is difficult to get the required power. In this paper, the performance according to the motion control of segmented SMA wire is evaluated. SMA wire is segmented by thermoelectric modules. The displacement of SMA wire according to load is measured and its hysteresis is surveyed.

Abstract: In recent years, as the robot technology is developed, the researches on the artificial muscle actuator that enables robot to move dexterously like biological organ become active. Actuators are one of the key technologies underpinning robotics. Particularly breakthroughs of power-to-weight ratio or energy-density in actuator technology have significant impacts upon the design and the control of robotic systems. The widely used materials for artificial muscle are the shape memory alloy and electro-active polymer. These actuators have the higher energy density than the electromechanical actuators such as the electric motor. However, there are some drawbacks because these actuators have the hysteretic dynamic characteristics. In this paper, the segment control for reducing the hysteresis of SMA is proposed and the simulation of an anthropomorphic robotic hand is performed using ADAMS. A new approach to design and control of SMA actuators is presented. SMA wire is divided into many segments and their thermal states are controlled individually in a binary manner(ON/OFF). The basic experiment for evaluating the dynamic characteristics of SMA wire actuator is performed.

Abstract: The application of electroactive polymer devices requires the availability of their properties at various operating conditions. This in turn necessitates a structure-property relationship based on an in-depth understanding of the underlying mechanism responsible for their strain-field response. Cellulose-based Electro-Active Paper (EAPap) has been studied as an attractive Electro Active Polymer (EAP) material for artificial muscles. The feasibility of EAPap material as an actuator/sensor application is greatly dependant on piezoelectric effect. In this paper, converse and di rect piezoelectric ef fect s of Electro-Active Paper materials are studied to characterize piezoelectric effects of EAPap. All experiments were conducted in an environmental chamber that can control temperature and humidity.

Abstract: This paper presents a new design of an artificial muscle actuator called tube-spring actuator (TSA) that is fabricated with dielectric elastomer. The new actuator construction includes two steps: the first is that a cylindrical actuator is manufactured with dielectric elastomer with multi-layer lamination process. Then a compressed spring is inserted to inside the tube as the second step of the process. The inner spring is used to maximize the axial deformation while constraining the radial contraction. This design enables effective linear actuation with largest amount strain. The monitored strain of active length is up to 15 percents. The manufactured actuator is applied to a robot hand as an example of the actual application.

Abstract: The IPMC, one of new sensing and actuating materials is known for the fast and flexible bending actuation upon electric fields. In this paper, we investigated the dynamic deformation characteristics of the novel IPMC according to several fabrication methods. First we studied the effect of the surface modification of metallic electrodes on the large deformation. Present results show that the sandblasting method can give more reliable and large deflections than the sandpapering method under the same control voltage because the platinum electrode can be infiltrated into the ionic-polymer by the sandblasting method. Second, the IPMC with Li+ counter ions shows more large deformation than that with any other counter ions. Also, present results show the dynamic hysteresis according to driving voltages.

Abstract: Biomimetic actuators that can produce soft-actuation but large force generation capability are of interest. NafionTM, an effective ionomeric material from DuPont, has been shown to produce large deformation under low electric fields (<10V/mm). In this effort, multi-walled carbon nanotube (M-CNT)/NafionTM nanocomposites were prepared by casting in order to investigate the effect of M-CNT loading in the range of 0 to 7 wt% on electromechanical properties of the MCNT/ NafionTM nanocomposites. The measured elastic modulus and actuation force of the MCNT/ NafionTM nanocomposites are drastically different, showing larger elastic modulus and improved electromechanical coupling, from the one without M-CNT. In this work, we attempted to incorporate an equivalent circuit analysis to address the effect of capacitance and resistance of such M-CNT/NafionTM nanocomposites that would differ from conventional IPMCs.

Abstract: One of the main problems for the use of ferroelectric materials for sensor applications, especially for tactile sensors, is the separation of the pyro- and piezoelectric responseproduced by temperature and pressure changes, respectively. We present two different approaches to achieve this goal. The first approach is based on the study of the signal in the frequency domain and uses a signal processing to separate the approach is based on a double layer configuration of electroactive polymers. In this case, the piezoelectric response is equal in each layer, whereas, the pyroelectric response dominates in the layer exposed to the temperature variations. The pyro- and piezoelectric responses are separated by estimating the diference between the signals of two layers and the signal from one of the layers, correspondingly.

Abstract: Biomimetic actuators that can produce soft-actuation but large force generation capability are of interest. Nafion, an effective ionomeric material from DuPont, has been shown to produce large deformation under low electric fields (<10V/mm). This response is caused by a direct electro-osmotic effect due to the existence and mobility of cations and subsequent swelling and deswelling of the material. In this effort, multiwalled carbon nanotube (MWNT)/Nafion nanocomposites were prepared by a casting in order to investigate the effect of MWNT loading in the range of 0 to 7 wt% on electromechanical properties of the MWNT/Nafion nanocomposites. The measured elastic modulus and actuation force of the MWNT/Nafion nanocomposites are drastically different, showing larger elastic modulus and improved electromechanical coupling, from the one without MWNT, implying that the effective MWNT loading is crucial to develop high-performance biomimetic actuators.