• Proceedings of the Korean Society For Composite Materials Conference
• /
• 2004.10a
• /
• pp.9-14
• /
• 2004

An approximate relationship of the strain and applied potential was derived for SWNTs and conductive polymer composite actuator. During the deriving process, we used an electrochemical system to model the electromechanical actuation of the composite film. This relationship can give us a direct understanding to the actuation of a nanoactuator

• International Journal of Control, Automation, and Systems
• /
• v.4 no.6
• /
• pp.748-755
• /
• 2006

In this paper, a trade-off design and fabrication of IPMC(Ionic Polymer Metal Composites) as an actuator for a flapping device have been described. Experiments for the internal solvent loss of IPMCs have been conducted for various combinations of cation and solvent in order to find out the best combination of cation and solvent for minimal solvent loss and higher actuation force. From the experiments, it was found that IPMCs with heavy water as their solvent could operate longer. Relations between length/thickness and tip force of IPMCs were also quantitatively identified for the actuator design from the tip force measurement of 200, 400, 640, and $800{\mu}m$ thick IPMCs. All IPMCs thicker than $200{\mu}m$ were processed by casting $Nafion^{TM}$ solution. The shorter and thicker IPMCs tended to generate higher actuation force but lower actuation displacement. To improve surface conductivity and to minimize solvent evaporation due to electrically heated electrodes, gold was sputtered on both surfaces of the cast IPMCs by the Physical Vapor Deposition(PVD) process. For amplification of a short IPMC's small actuation displacement to a large flapping motion, a rack-and-pinion type hinge was used in the flapping device. An insect wing was attached to the IPMC flapping mechanism for its flapping test. In this test, the wing flapping device using the $800{\mu}m$ thick IPMC. could create around $10^{\circ}{\sim}85^{\circ}$ flapping angles and $0.5{\sim}15Hz$ flapping frequencies by applying $3{\sim|}4V$.

• Structural Monitoring and Maintenance
• /
• v.5 no.2
• /
• pp.297-311
• /
• 2018

Plate and shell structure is widely applied in engineering, i.e. building roofs, aircraft wings, ship platforms, and satellite solar arrays. Its vibration problem has become increasingly prominent due to the tendency of lightening, upsizing and flexibility. As a new smart material with great actuating force and toughness, macro-fiber composite (MFC) is composed of piezoelectric fiber and epoxy resin basal body, which can be directly pasted onto the surface of plate and shell and is suitable for vibration control. This paper deduces the actuation equation of MFC coupled plate in different boundary conditions, an equivalent finite element modeling method is proposed which uses MFC actuating force as the applied excitation, and on this basis the active control simulation and experiment of MFC over plate and shell structure vibration are accomplished. The results indicate that MFC is able to implement effective control over plate and shell structure vibration in multi-band range. The comparison between experiment and simulation proves that the actuation equation deduced herein, effective and practicable, can be applied into the simulation calculation of MFC vibration control over plate and shell structure.

• Journal of the Korean Society of Propulsion Engineers
• /
• v.19 no.1
• /
• pp.68-75
• /
• 2015

In this paper, unsteady characteristics of pressure in solid rocket motor were analyzed by using response of pintle actuation, pressure and thrust data from ground test. Pressure and thrust in solid rocket motor can be controlled in real time by varying nozzle throat area with pintle, installed in the valve. Unsteady characteristics of pressure can be observed in this system occurred by various reasons. Two critical reasons, error of pintle actuation and ablation of center tube, are found and effects of each reason can be analyzed individually by re-prediction of pressure with response of pintle actuation and analyzing thrust to pressure ratio.

• Applied Chemistry for Engineering
• /
• v.17 no.6
• /
• pp.586-590
• /
• 2006

As one of electro active polymers for soft smart materials, the ionic polymer metal composites (IPMC) are easy to produce through chemical reduction processing and show high displacements at low voltage. When the IPMC actuates, the deformation depends on a few factors including the structure of based membrane, species and morphology of the metal electrodes, the nature of cations and the level of hydration. As previously published, we have been studying on improvement of actuation through surface electrode modification of IPMC to grasp the effect of electrode morphology on actuation. This study is comparative experiments through the chemical reaction and deposition by ion beam assisted deposition (IBAD) in order to prepare the very thin and homogeneous surface electrode of IPMC. The IPMCs were prepared with different surface roughness of polymer membrane, and the influence of the surface roughness on the actuation was studied. By investigating the electrical properties and driving displacement, the actuating properties of IPMC with different surface roughness were studied.

• Journal of Sensor Science and Technology
• /
• v.7 no.4
• /
• pp.271-278
• /
• 1998

A ISFET-based glucose sensor has inherent problems such as low sensitivity, drift effect and long response time. For that reason, a amperometric actuation technique was introduce to make a highly sensitivity of the ISFET glucose sensor with a Pt actuator, which electrolyzes $H_2O_2$, one of the by a by-products of the oxidation reaction of glucose. Moreover, a potential-step measurement method detecting response by only the electrolysis of $H_2O_2$ was developed for eliminating a drift problem. The operation characteristics of ISFET-based glucose sensor was improved by using the amperometric actuation and a measurement techniques. The fabricated ISFET glucose sensor is shown good operation such as characteristics(30mM PBS, about 26mV/decade) and linearity. A portable glucose meter with a highly resolution by using the fabricated ISFET-based glucose sensor with Pt actuation was developed and its characteristics investigated.

• Journal of Aerospace System Engineering
• /
• v.15 no.3
• /
• pp.57-64
• /
• 2021

In the study, to minimize the error on guided control of the KV (Kill Vehicle) and to secure the hit-to-kill performance, a position accuracy inspection for the DACS (Divert and Attitude Control System) actuation system was proposed. The accuracy performance of the DACS actuation system is one of the most important factors in the interception of ballistic missiles. In order to validate actuation control accuracy of DACS system, an inspection item was set for position accuracy, and the inspection system was designed for DACS pintle. To measure the absolute position value of the DACS pintle, an external measurement system was developed using laser displacement sensors. The inspection system was designed so that it can be compared with the actuation command in real time. The proposed position accuracy inspection system can be inspected not only in a DACS system but also in missile system level. The position accuracy inspection was performed using the designed inspection system, and analysis of the inspection result.

• Journal of the Korean Society for Precision Engineering
• /
• v.30 no.6
• /
• pp.658-664
• /
• 2013

Bending actuators composed of cellulose with an electrically conducting polymer (CP) are fabricated and their performance is characterized in the air. Two different counter ions, perchlorate and tetrafluoroborate are used as dopant ions in the polyaniline CP processing. CP-cellulose-CP trilayer and CP-cellulose bilayer samples are fabricated with different dopant ions, and their actuation performance is evaluated in terms of tip displacement, blocked force and electrical power consumption along with the humidity level and actuation frequency. The trilayer samples substantially enhanced the tip displacement compared to the bilayer ones. The actuation performance of the trilayer actuator is three times better than that of original cellulose electro-active paper (EAPap) actuator. The displacement and blocked force of CP-EAPap actuators are dependent on the humidity and frequency.

• Proceedings of the IEEK Conference
• /
• 2005.11a
• /
• pp.147-150
• /
• 2005

Low actuation voltage and no contact stiction are the important factors to apply MEMS RF switches to mobile devices. Conventional electrostatic MEMS RF switches require several tens of voltages for actuation. In this paper we propose PAS MEMS RF switch which adopt PZT actuators and seesaw cantilevers to meet the above requirements. The fundamental structures of PAS MEMS switch were designed, optimized, and fabricated. Through the developed processes PAS SPDT MEMS RF switches were successfully fabricated on 4" wafers and they showed good electrical properties. The driving voltage was less than 5 volts. And the insertion loss was -0.5dB and the isolation was 35dB at 5GHz. The switching speed was about 5kHz. So these MEMS RF switches can be applicable to mobile communication devices or wireless multi-media devices at lower than 6GHz.

• International Journal of Aerospace System Engineering
• /
• v.4 no.1
• /
• pp.13-21
• /
• 2017

In this paper, we present some results on performance analysis for flap actuation system of aircraft. For this, by utilizing MATLAB/Simulink solution, which is widely used physical model-based design tool, we particularly construct the architecture of the analysis model consisting of the main three phases: 1)commanding and outer-controlling the flap angle through flight control computer; 2)generating hydraulic/mechanical power through control module and power drive unit; 3)transmitting torque and actuating the flap through torque tube and rotary geared actuators. For mimicking the motion of the actual flap, we apply each mechanical component, which is already being used in actual aircraft, to our performance analysis model so that it guarantees the congruency of the simulation results. That is, we reflect the actual specifications of flap hardware and software as parameters of the model. Finally, simulation results are presented to illustrate the model.