• Proceedings of the Korean Fiber Society Conference
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• 2003.04a
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• pp.303-304
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• 2003

Conducting polymers show several unique features, wherein electrical and optical properties change drastically during electrochemical reaction. By making use of these phenomena, several electronic devices have been fabricated, for instance, electrochromic displays, rechargeable batteries and electroplasticity memory devices. Electromechanical actuators using conducting polymers have been proposed by Baughman et. al [1]. (omitted)

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2014.04a
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• pp.374-378
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• 2014

The piezoelectric materials convert from mechanical energy to electrical energy. The piezoelectric materials are used in various engineering applications such as piezoelectric ultrasonic actuators. Since the piezoelectric coupling characteristics of the actuator systems should be considered at the initial design stage, it is essential to analyze the piezoelectric coupling characteristics of the ultrasonic actuators. In this study, we analyzed the electromechanical characteristics of piezoelectric stacked actuator using the equivalent circuit model with modal mass stiffness parameters. It was compared the admittance of piezoelectric stack actuators with the analytical circuit model and the finite element model. Also, the coupling coefficient of piezoelectric stack actuator was discussed according to the number of stacks of actuators.

• Smart Structures and Systems
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• v.16 no.1
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• pp.27-46
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• 2015

Active surface adjustment of cable net structures is becoming significant when large-size cable net structures are widely applied in various fields, especially in satellite antennas. A general-duty adjustment method based on active cables is proposed to achieve active surface adjustment or surface profile reconfiguration of cable net structures. Piezoelectric actuators and voice coil actuators are selected for constructing active cable structures and their simplified mechanical models are proposed. A bilevel optimization model of active surface adjustment is proposed based on the nonlinear static model established by the direct stiffness method. A pattern search algorithm combined with the trust region method is developed to solve this optimization problem. Numerical examples of a parabolic cable net reflector are analyzed and different distribution types of active cables are compared.

• Composites Research
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• v.18 no.5
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• pp.40-46
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• 2005

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.11a
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• pp.731-734
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• 2005

Generally, characteristics of electromechanical actuators are coupled with the mechanical and the electrical properties. Important mechanical parameters of these actuators are the achievable force and displacement in the presence of electric field. These mechanical parameters are related to the stress and strain of the materials and the actuator geometry. This paper presents how to measure the blocked force by using the micro-balance. The blocked force is defined as the force produced by the transducer under an applied voltage when the tip is constrained to zero motion. Also, a theoretical force by using the cantilever beam model is calculated under elastic domain. From the sample of 4 cm $\times$ 1 cm $\times$ 20 $\mu$m, the blocked farce measured from the equipment is 20.3 $\mu$N at 8 V$_{DC}$. By comparing it with the theoretical value, 24.9 $\mu$N, the blocked force measurement is acceptable. The furce measurement is also investigated with different AC electric fields and the frequency.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2009.10a
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• pp.316-317
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• 2009

The ion-exchange membrane, Nafion, remains as the benchmark for a majority of research and development in IPMC technology. In this research, we employed a novel ionomer named by sulfonated poly(styrene-ran-ethylene) (SPSE) that is crosslinked by UV irradiation. The sulfonic acid groups were stable during the UV irradiation crosslinking process. Water uptake, ion exchange capacity, and proton conductivity are characterized for both pure SPSE and crosslinked SPSE membrane. The bending responses of SPSE actuators under both direct current (DC) and alternating current (AC) excitations were investigated. The voltage-current behaviors of the actuators under AC excitations are also measured. Results showed the crosslinked SPSE actuators have better electromechanical performance than that of pure SPSE actuator with regard to tip displacement as a novel smart material.

• Smart Structures and Systems
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• v.5 no.5
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• pp.547-564
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• 2009

Based on the theory of piezoelasticity, an analytical solution for a typical multilayer piezoelectric composite cantilever is obtained by the Airy function method. The piezoelectric cantilever may consist of any number of layers. Moreover, the material and thickness for different layers may be different. The solution obtained in the present paper is concise and can be easily applied for the bending analysis of multilayer piezoelectric actuators considering the effect of bonding layers and electrodes. At last, a comprehensive parametric study is conducted to show the influence of electromechanical coupling (EMC), the number of piezoelectric layers, the elastic modulus of elastic layer and the thickness ratio on the bending behavior of actuators. Some interesting results for the design of multilayer piezoelectric actuators are presented.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2007.06a
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• pp.637-638
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• 2007

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.26 no.5
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• pp.360-366
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• 2013

For conventional electrical actuators, the materials are mainly made up of metals, which mean they are prone to corrosion and electrical sparking. Replacing these systems with polymer metal composite based materials can be solved both problems. Considering their excellent electromechanical property, low device fabrication cost, light weight, and good electrical conductivity, the actuator based on ionic polymer metal composite (IPMC) was fabricated using Nafion film, NaOH 0.1 molar solution, and Au electrode. IPMCs exhibit good electrostatic property which means they can in principle be used in making actuators based on electromechanical motions. The resistance measurements of Nafion film after soaking in NaOH and deionized water were demonstrated and compared each other. The result of sample soaked in NaOH showed better electrical conductivity than in deionized water. The fabricated IPMC actuator exhibits a large deformation of bending displacement of approximately 9 mm with applied low AC voltage 6.89 V at 2.84 Hz. The result of computer simulation was also very similar and shown as a bending displacement of 8.6085 mm.

• Journal of Mechanical Science and Technology
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• v.20 no.11
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• pp.1914-1919
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• 2006

Recently, the microrobots powered by biological muscle actuators were proposed. Among the biological muscle actuators, frog muscle is well known as a good muscle actuator and has a large displacement, actuation forces and piezoelectric properties. Therefore, for the application of the biomimetic microrobot, this paper reports the electromechanical properties of frog muscle. First of all, the experimental setup has been established for measuring generative force of the frog muscle. Through the various electrical stimulating inputs to the frog muscle, we measured the contractile force of the frog muscle. From the measuring results, we found that the actuating contractile force responses of the frog muscle are determined by the amplitude, frequency, duty ratio, and wave form of the stimulation signal. This study will be beneficial for the development of the microrobot actuated by frog muscle.