• Journal of the Korean Society of Manufacturing Technology Engineers
• /
• v.26 no.1
• /
• pp.89-99
• /
• 2017

This paper describes the development of a thigh wearable robot for power assistance during stair climbing. In the wearable robot developed in this study, high-power BLDC motors and high-capacity harmonic reduction gears are used to effectively assist the thigh muscle during stair climbing. In particular, normal ground and stair are distinguished accurately by using wireless smart shoes, and the stair climbing assistance is performed by activating the actuators at an appropriate time. Impedance of the hip joint was effectively reduced by performing friction compensation of the gears, and a wearing adjustment mechanism was designed to fit the robot to the thigh by conveniently modifying the width and tilting angle of the robot using set collars. Consequently, the performance of the developed thigh wearable robot was verified through stair climbing experiments with EMG measurement.

• Journal of Sensor Science and Technology
• /
• v.8 no.1
• /
• pp.80-88
• /
• 1999

This paper deals with the position determination problem of stereo camera systems used as a sensor for 3D robotic manipulation. Stereo cameras having parallel rays of sight and been set up on the same baseline are assumed. The distance between the sensor and the space measured is determined so as to get insensitive parameters to the uncertainty of control points used for calibration and to satisfy the error condition set by considering the repeatability of the robot. The baseline width is determined by minimizing the mutual effect of 3D positional error and stereo image coordinate error. Unlike existing techniques, the technique proposed here is developed without complicated constraints and modelling process of the object to be observed. Thus, the technique of this paper is more general and its effectiveness is proved by simulation.

• Laser Solutions
• /
• v.16 no.4
• /
• pp.17-23
• /
• 2013

The research for the development of roll-to-roll printing process is actively underway on behalf of the existing semiconductor process. The roll-to-roll printing system can make the electronic devices to low-cost mass production. This study is performed for developing the manufacturing technology of the printing roll used in the printing process of electronic devices. The indirect laser engraving technology is used to create printable roll and the printable roll is made out of the chrome coated roll after coating copper and polymer on the surface of steel roll, ablating the polymer on the surface of roll and etching the roll. The 3 dimensional laser scanner and roll rotating systems are constructed and the system control program is developed. We have used the fiber laser of 100 W grade, the 3 dimensional laser scanner and the 3 axes moving stage system with a rotating axis. We have found the optimal conditions by performing the laser patterning experiments and can make the minimum line width of $24{\mu}m$ by using the developed 3 dimensional laser scanner system.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.38 no.10
• /
• pp.966-972
• /
• 2010

Damping characteristics of a Helmholtz resonator to passively control the combustion instability were investigated by linear acoustic analysis and atmospheric acoustic tests. Its orifice length and diameter were selected as the design parameters and supplied SPL(sound pressure level) effect on damping characteristics were investigated. Damping capacity is improved by decreasing the orifice length as well as by increasing the orifice diameter. Also, the results showed that the damping capacity of the resonator decreased nonlinearly about above 110 dB and instabilities in the nonlinear region were more effectively suppressed by increasing the orifice diameter.

• Proceedings of the Korean Society for Agricultural Machinery Conference
• /
• 2000.11c
• /
• pp.744-748
• /
• 2000

The characteristics of $CO_2$ exchange between plant and human modules, absorption rate of NO$_2$, and growth of lettuce were examined in an urban-type plant factory(UPF). With 150 lettuce plants, $CO_2$ concentrations of plant module were 600 ~ 700$\mu$mol mol$^{-1}$ at average leaf weight of 130g.plant$^{-1}$ and 900~1100$\mu$mol.mol$^{-1}$ at 75g.plant$^{-1}$ for one and two persons' stay in the human module, respectively. When the air of 0.13, 0.30 and 0.45 $\mu$molㆍmol$^{-1}$ NO$_2$ in a human module was circulated ON/OFF 10/20min between the human and plant modules, $NO_2$ decrement in the chamber during 10 min was 0.040, 0.109, and 0.149 $\mu$mol, respectively. The lettuces grown at 0.45 $\mu$molㆍmol$^{-1}$ $NO_2$ during experimental period showed no significant differences in growth factors such as leaf width, leaf length, leaf area and fresh weigh, and in the quality between treated and control.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2005.06a
• /
• pp.1181-1185
• /
• 2005

Microstereolithography has evolved from the stereolithography technique, and is also based on a light-induced layer-stacking manufacturing. Integral microstereolithography is proposed for building a 3D microstructure rapidly, which allows the manufacture of a complete layer by one irradiation only. In this study, we developed the integral microstereolithography apparatus based on the use of $DMD^{TM}$ as dynamic pattern generator. It is composed of Xenon-Mercury lamp, optical devices, pattern generator, precision stage, controllers and the control program. Also, we estimated curing characteristics in photopolymer. The relationship between the viscosity of diluent-oligomer solutions and curing width, irradiation time and curing property has been studied.

• Korean Journal of Applied Biomechanics
• /
• v.13 no.3
• /
• pp.15-26
• /
• 2003

This study was conducted to investigate the performance times, CM position and CM speed, pole chord length and pole chord angle, whole body angular momentum(X axis), and grip width in pole vault event according to the event and phase; touch down, pole plant, take-off, maximum pole bending pole straight, pole release, peak height, and foot contact, pole contact, free flight. The pole vaulting of four male elite vaulters including six trial were filmed using two video digital cameras at 60 Hz at 56th national athletic match, and data were collected through the DLT method of three dimensional cinematography. In general the better jumper is, the longer the performance time is. And the greater CM speed is, and the better his transformation ability of CM horizontal speed into vertical speed is. As he uses a longer pole, his grip is higher, and it is a enough for him to rock back his body, so that he pulls and pushes the pole well keeping his hips close to. An greater maximum angular momentum and early positioning of the hips parallel to the bar makes his body far side of the bar and his bar clearance easier. Specially our national jumper needs to have more powerful braking force during foot contact phase, and take his body on the pole after maximum pole bending, and pull and push the pole strongly keeping his hips close to. Also he needs to have stronger muscular strength in order to control the longer pole and use the pole of proper tension more efficiently.

• Journal of Korea Multimedia Society
• /
• v.4 no.1
• /
• pp.75-81
• /
• 2001

A EBCOT(Embedded Block Coding with Optimized Truncation) is image compression codec using in JPEG2000, currently the new standard for still image coding. this paper proposes multi-channel video transfer system with EBCOT using a single codec to transfer video to difference band-width channel. This parer testify that compression rate of EBCOT higher than ordinary VLC using RLC and Huffman codec and apply EBCOT to JPEG structure. this structure increases parallelism and error resilience using black coding method. finally it looks into difficult to apply MPEG structure to multi channel video transfer system, and proposes solution using EBCOT.

• Proceedings of the Korean Society of Near Infrared Spectroscopy Conference
• /
• 2001.06a
• /
• pp.1252-1252
• /
• 2001

The aim of this study was to evaluate the possibility to characterize and classify waxes applied on some type of cheeses to obtain good stability during handling and transportation. Generally, waxes are obtained from the petrochemical industry, nowadays there is the possibility to also use biodegradable waxes produced from microorganisms. Preliminary studies were carried out to optimize sample presentation in NIR analysis, such as melting conditions (influence of temperature) and coat thickness of wax. 12 waxes (biodegradable or not) were analysed by using an InfraAlyzer 500 (Bran+Luebbe). The sample size was performed cutting pieces of 1.5 cm (height) x 1.5 cm (width) x 1.5 mm (thickness), previously melted at 9$0^{\circ}C$. NIR spectra were collected at room temperature, and data were processed by Sesame Software (Bran+Luebbe) to evaluate qualitative differences among samples by cluster analysis. Waxes were gathered on the basis of their origin (petrochemical or microbial). To better understand the significance of the NIRS bands discriminating among waxes, a two-dimensional correlation with FT-IR spectra, collected by a FT-IR/ATR 420 (JASCO) instrument, was made using 2DCORR program (Galactic Industries). On the basis of its classification power, NIRS appears to be a promising tool when used in routine analysis for a qualitative control of raw materials.

• Journal of the Korean Institute of Telematics and Electronics D
• /
• v.35D no.8
• /
• pp.8-14
• /
• 1998

A new process is developed to improve the electrical characteristics of high .beta. and low saturation voltage power transistor for lamp solenoid driver application. To prevent punch-through breakdown, appropriate combination of base doping and base width is necessary in the range of operating voltage of the circuit. The optimum values of base doping and sheet resistance are $Q_{D}$= $1.5{\times}10^{14}$atoms/$\textrm{cm}^2$ and $R_{s}$= 350 $\Omega/\square$ base wodtj $W_{B}$= $2.5{\mu}m$respectively. Under this condition it is possible to control $\beta$ of the transistor to 1500, maintaining $VB_{CBO}$ =200V. To reduce scattered distribution of .beta. of the devices on the wafer, it is necessary to improve emittter predeposition process. As a result, scattered distribution of .beta. of the devices on the wafer was reduced to 1/6 by using the new process. To improve collector to emitter forward voltage drop, $V_{ECF}$ of damper diode, an additional silicon etching process is used, which resulted in improving the value of $V_{eCF}$ from 2.8 V to 1.8V. With the suggested process superior device performance and higher yield are achieved.