• International Journal of Control, Automation, and Systems
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• v.2 no.3
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• pp.343-353
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• 2004

This paper presents the survivability, mobility, and functionality of a rover as part of a radar system for polar regions. Rovers can provide autonomy and precision for radars used to measure ice thickness and other characteristics of ice sheets in Greenland and Antarctica. These rovers can be used to move radar antennas in precise patterns for synthetic aperture radars while providing environmental protection and power to the onboard radar equipment. This paper describes the mobility, actuation, sensing, winterization, control, and virtual prototyping of a polar rover. The rover has been successfully tested in Greenland.

• Journal of Sensor Science and Technology
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• v.18 no.5
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• pp.353-358
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• 2009

Ionic polymer metal composite(IPMC) has been used as a promising material for various actuator applications. The IPMC actuator is difficult to be fabricated with complicated 3-dimensional shape. We propose a simple heat treatment process that can fabricate IPMC actuator with various shapes. Experimental results show the pre-shaped IPMC actuator by heat treatment does not show any degradation of its actuation abilities such as bending displacement, generation force and reliability in bending motion.

• Journal of Electrical Engineering and Technology
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• v.2 no.2
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• pp.263-266
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• 2007

We report a nickel optical MEMS switch, being able to rotate through a large angle and to accommodate multiple channels. The proposed optical switch consists of a thin nickel mirror and two torsion springs supporting the mirror. The torsion springs are designed using a finite element method (FEM) such that plastic deformation of the thin nickel is avoided during the large torsion actuation. For switching speed improvement, transient vibration of the released mirror is suppressed by optimizing the mirror design and a fast switching response of $200\;{\mu}s\;(pull-down)/300\;{\mu}s\;(pull-up)$ is demonstrated.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2005.04a
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• pp.226-230
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• 2005

This paper presents the actuation performance of a conducting shape memory polyurethane (CSMPU) actuator. We introduced a concept of shape memory polyurethane activated by electric power while conventional shape memory polyurethanes are activated by external heat source. A conducting shape memory polyurethane actuator was manufactured by adding cabon nano-tube to conventional shape memory polyurethane. The main problem of the previous CSMPU was bad dispersion of carbon nano-tubes in polyurethane. In this paper, we have tried to find manufacturing method to solve the dispersion problem. With a lot of elaborative works, we have developed conducting shape memory polyurethane actuator with good electrical performance. The actuation performance of the developed conducting shape memory polyurethane actuator was measured and assessed.

• Journal of the Korean Society for Precision Engineering
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• v.33 no.3
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• pp.173-181
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• 2016

This paper reports on the development of a roller-cam clutch mechanism. This mechanism can transfer bidirectional torque with high backdrivability, as well as increase actuation energy efficiency, in electrical exoskeleton robots. The developed mechanism was installed at the robot knee joint and unclutched during the swing phase which uses less metabolic energy, thereby functioning as a passive joint. The roller-cam clutch aimed to increase actuation energy efficiency while also producing high backdrivability by generating zero impedance for users during the swing phase. To develop the mechanism, mathematical modeling of the roller-cam clutch was conducted, with the design having more than three safety factors following optimization. Titanium (Ti-6AL-4V) material was used. Finally, modeling verification was done using ANSYS software.

• Polymer(Korea)
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• v.25 no.6
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• pp.826-832
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• 2001

In this study, PPy/gold/mylar type electroactive bi-layer actuator was prepared by the electrochemical polymerization of pyrrole onto the gold/mylar film and the actuation characteristics were studied using bending beam method. Conducting polymer-based actuators undergo volumetric changes due to the movement of dopant ions into the film during the electrical oxidation process. The bilayer films exhibited different actuation characteristics depending on dopant ion size. It was observed that the relatively small dopant ion (i.e. toluene sulfonate) moved into the PPy film at oxidized state, so volume expanded to result in bending motion. In case of the film having large dopant ion (i.e. dodecylbenzenesulfonate), volume expansion was observed at reduced state. This is due to the incorporation of $Na^+$ counterion with water molecules, while the large dopant ion was fixed in the film due to the limited mobility during tile redox process.

• Journal of computational fluids engineering
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• v.10 no.2
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• pp.48-53
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• 2005

This work discusses the numerical analysis, the design and experimental test of the SMA actuator along with its capabilities and limitations. Convective heating and cooling using water actuate the SMA(Shape memory alloy) element of the actuator. The fuel such as propane, having a high energy density, is used as the energy source for the SMA actuator in order to increase power and energy density of the system, and thus in order to obviate the need for electrical power supplies such as batteries. The system is composed of a pump, valves, bellows, a heater(burner), control unit and a displacement amplification device. The experimental test of the SMA actuator system results in 150 MPa stress(force : 1560 N) with $3\%$ strain and 0.5 Hz. actuation frequency. The actuation frequency is compared with the prediction obtained from numerical analysis. For the designed SMA actuator system, the results of numerical analysis were utilized in determining design parameters and operating conditions.

• Journal of Sensor Science and Technology
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• v.23 no.3
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• pp.165-169
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• 2014

An existing infrared (IR) analysis system is generally composed of infrared source, IR focusing lenses, IR detector, and optical chopper. An optical chopper is widely used in combination with lock-in amplifier to improve the signal-to-noise ratio by periodically interrupting incident light beam. During recent years, a few researches on miniaturized optical chopper have been reported to apply to micro-scaled optical systems. In this paper, a micro optical chopper operated by electromagnetic actuation is proposed and applied to a miniaturized micro-scaled optical system operating in IR spectral range. Additionally, the fabrication method of the proposed micro chopper is demonstrated. The proposed micro optical chopper is composed of the polydimethylsiloxane (PDMS) membrane, solenoid, and permanent magnet. The permanent magnet is bonded on the PDMS membrane using an ultraviolet-activated adhesive. The operation of the chopper is based on the attractive and repulsive forces between permanent magnet and solenoid induced by an electrical current flowing through the solenoid. The fabricated micro optical chopper could operate up to 200 Hz of frequency. The maximum operating distance of the chopper with 7mm diameter membrane was $750{\mu}m$ at 100 Hz of frequency.

• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.1211-1214
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• 2004

In this paper, we propose to use variable inlet guide vane as a means of active surge control to solve above problems. There is some advantage. For example, since the inlet guide vanes are already present in POSCO, no additional actuation device is required. We can collect all data easily which is related to the test and can simulate new model using our compressors. We can obtain the result that blow-off valve is opened less 5% and can operate air compressor automatically and more efficiently. Through a simulation example, the effectiveness of the proposed schemes is illustrated.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2006.11a
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• pp.444-450
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• 2006

IPMC actuators have been developed with multi-walled carbon nanotubes(MWNT) and $Nafion^{\circledR}$ ionic polymers. MWNT with different diameters of $3{\sim}5,\;4{\sim}6$ and $10{\sim}15$ nm and length of $10{\sim}20{\mu}m$ were used to enhance the mechanical and electrical performances of IPMC actuators. Ultrasonic treatment and high speed mixing were used to disperse MWNT homogeneously in $Nafion^{\circledR}$ solution. The electroless plating technique is used to make electrodes on the both side of the composite membrane. SEM and TEM images were taken to characterize the surface and micro-structures of the composite actuators. In this study, improved IPMC actuators were developed and compared with respect to bending actuation performance and electrical power consumptions.