• 제어로봇시스템학회:학술대회논문집
• /
• 2004.08a
• /
• pp.1786-1790
• /
• 2004

The main objective of this paper is to analyze the performance of various force control algorithms in improving and adjusting the compliance of industrial robots in contact with their environment. Some of fundamental force control algorithms such as sensorless control, impedance control and hybrid position/force control are theoretically analyzed and simulated for various situations of an environment, and then a series of experiments using them were performed. In this paper, a control scheme to use position control in implementing the impedance control was investigated in order to nullify the effect of joint friction. The new reference trajectory is generated using contact force feedback and original desired trajectory. And an inner position control loop is designed to provide accurate position tracking for the new reference trajectory and good disturbance rejection. Experiments to insert a peg in a hole (so-called the peg-in-a-hole task) were performed with HILS (hardware-in-theloop simulation) system based on the results of the analyses and simulations on the characteristics of each control algorithm. The experiments showed that various force control methods improved the performance of robots in close contact with the environment by adjusting their compliance with respect to an arbitrary set of coordinates.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
• /
• 2006.04a
• /
• pp.393-398
• /
• 2006

Currently, 54 kinds of digital maps are provided by National Geographic Information Clearinghouse and the majority of those maps are based on aerial photographs or satellite image. The digital maps which symbolize and simplifies the topography and objects from ortho-photos does not reflect the objects 'shapes and facilities' changes. Especially, underground structures and complex building shapes are not correctly identifies by ortho-photos. Furthermore, the 1/1,000 and 1/500-1/2,500 maps for urban area produced by some local government or public organizations have detailed information with high precision, it is not easy to update the information due to the frequent changes of structures in the city. Although some efforts to solve this problem such as conducting field survey and shorten the survey period were tried, it is not the fundamental solution due to the high cost. Therefore, in this study, a realtime renewal and update of digital map using general survey are suggested. By assigning absolute coordinates to the general survey products and matching with digital maps, it is possible to update the digital map economically and rapidly. In addition, it is suggested that the construction of DB for general survey and sharing among survey companies to solve the duplicated survey.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.59 no.12
• /
• pp.2240-2244
• /
• 2010

We have studied white OLED using two types of Zn-complexes as a emitting layer. We synthesized new emissive materials $Zn(HPQ)_2$ as a yellow emitting material and $Zn(HPB)_2$ as a blue emitting material. Zn-complexes have a low molecular compound and thermal stability. The fundamental structures of the fabricated OLED was ITO / NPB (40nm) / $Zn(HPB)_2$ (30nm) / $Zn(HPQ)_2$ / LiF / Al. We varied the thickness of the $Zn(HPQ)_2$ layer 20, 30 40 nm. When the thickness of the $Zn(HPQ)_2$ layer was 20 nm, white emission was achieved. The maximum luminance was 12,000 cd/$m^2$ at a current density of 800 mA/$cm^2$. The CIE coordinates of the white emission was (0.319. 0.338) at an applied voltage of 10 V.

• Proceedings of the KIEE Conference
• /
• 2008.05a
• /
• pp.167-168
• /
• 2008

Organic light emitting diodes (OLEDs) show a lot of advantages for display purposes. Because OLEDs provide white light emission with a high efficiency and stability, it is desirable to apply OLEDs as an illumination light source and back light in LCD displays. We synthesized new emissive materials, namely $Zn(HPB)_2$ and Zn(HPB)q, which have a low molecular compound and thermal stability. We studied white OLEDs using $Zn(HPB)_2$ and $Zn(PQ)_2$. The fundamental structures of the white OLEDs were ITO / NPB (40 nm) / $Zn(HPB)_2$ (40 nm) / $Zn(PQ)_2$ (20 nm) / LiAl (120 nm). As a result, we obtained a maximum luminance of $4200cd/m^2$ at a current density of $440mA/cm^2$. The CIE (Commission International de l'Eclairage) coordinates are (0.319, 0.338) at an applied voltage of 10 V.

• Advances in Computational Design
• /
• v.1 no.1
• /
• pp.1-25
• /
• 2016

Domes are architectural and elegant structures which cover a vast area with no interrupting columns in the middle, and with suitable shapes can be also economical. Domes are built in a wide variety of forms and specialized terms are available to describe them. According to their form, domes are given special names such as network, lamella, Schwedler, ribbed, and geodesic domes. In this paper, an optimum topology design algorithm is performed using the enhanced colliding bodies optimization (ECBO) method. The network, lamella, ribbed and Schwedler domes are studied to determine the optimum number of rings, the optimum height of crown and tubular sections of these domes. The minimum volume of each dome is taken as the objective function. A simple procedure is defined to determine the dome structures configurations. This procedure includes calculating the joint coordinates and element constructions. The design constraints are implemented according to the provision of LRFD-AISC (Load and Resistance Factor Design-American Institute of Steel Constitution). The wind loading act on domes according to ASCE 7-05 (American Society of Civil Engineers). This paper will explore the efficiency of various type of domes and compare them at the first stage to investigate the performance of these domes under different kind of loading. At the second stage the wind load on optimum design of domes are investigated for Schwedler dome. Optimization process is performed via ECBO algorithm to demonstrate the effectiveness and robustness of the ECBO in creating optimal design for domes.

• IEIE Transactions on Smart Processing and Computing
• /
• v.3 no.4
• /
• pp.226-233
• /
• 2014

This paper presents an external light evasion method that rectifies the problem of misrecognition due to external lighting. The fundamental concept underlying the proposed method involves recognition of the differences between two images and elimination of the desynchronized external light by synchronizing the image sensor and inner light source of the optical touch screen. A range of artificial indoor light sources and natural sunlight are assessed. The proposed system synchronizes with a Vertical Synchronization (VSYNC) signal and the light source drive signal of the image sensor. Therefore, it can display synchronized light of the acquired image through the image sensor and remove external light that is not from the light source. A subtraction operation is used to find the differences and the absolute value of the result is utilized; hence, the order is irrelevant. The resulting image, which displays only a touched blob on the touchscreen, was created after image processing for coordination recognition and was then supplied to a coordination extraction algorithm.

• Current Industrial and Technological Trends in Aerospace
• /
• v.6 no.2
• /
• pp.80-89
• /
• 2008

Photogrammetry is a non-direct 3-dimensional coordinate measurement technique using 2-dimensional photographic images. For reconstruction 3-dimensional data from the 2-dimensional photos, photogrammetry uses the fundamental principle of triangulation. Digital photogrammetry solve for the camera location and coordinates simultaneously through the mapping, scaling and bundle processing in software processing. In this paper, several applications for photogrammetry measurement are introduced, such as 'photogrammetric measurement of the gravity deformation of a cassegrain type antenna', 'analysis of photogrammetry data from ISIM mockup', 'underwater photogrammetric verification of nuclear fuel assemblies', 'spacecraft optical bench measurement' and 'spacecraft ground support equipment measurement'.

• Journal of Institute of Control, Robotics and Systems
• /
• v.14 no.4
• /
• pp.353-360
• /
• 2008

The LGP with nanometer structures resulted in enhancement of optical efficiency. Its fundamental mechanism is to recycle the polarized light via one round-trip through QWP(Quarter-Wave Plate) but the maximum efficiency to reach with this method is limited up to 2. To get the larger efficiency than this limited one a LGP with nanometer-patterned grating is suggested. For its optimum design the computer simulation is performed and suggests a grating that the spatial frequency between adjacent patterns is 500nm, its height 250nm, duty cycle 50%, and its cross section is rectangular. On the basis of simulation results the LGP with nanometer-patterned grating is fabricated and its optical properties such as angular intensity distribution and CIE color coordinates are characterized. The angles of transmitted light are nearly the same as the results expected from the generalized Snell's law. Thus the Mathematica code, developed in this experiment, will be applied to designing the optimized LGP. The LGP with nanometer-patterened grating shows the enhancement of transmitted intensity distribution up to 4.9 times.

• Nuclear Engineering and Technology
• /
• v.41 no.10
• /
• pp.1347-1360
• /
• 2009

A multi-dimensional component for the thermal-hydraulic system analysis code, MARS, was developed for a more realistic three-dimensional analysis of nuclear systems. A three-dimensional and two-fluid model for a two-phase flow in Cartesian and cylindrical coordinates was employed. The governing equations and physical constitutive relationships were extended from those of a one-dimensional version. The numerical solution method adopted a semi-implicit and finite-difference method based on a staggered-grid mesh and a donor-cell scheme. The relevant length scale was very coarse compared to commercial computational fluid dynamics tools. Thus a simple Prandtl's mixing length turbulence model was applied to interpret the turbulent induced momentum and energy diffusivity. Non drag interfacial forces were not considered as in the general nuclear system codes. Several conceptual cases with analytic solutions were chosen and analyzed to assess the fundamental terms. RPI air-water and UPTF 7 tests were simulated and compared to the experimental data. The simulation results for the RPI air-water two-phase flow experiment showed good agreement with the measured void fraction. The simulation results for the UPTF downcomer test 7 were compared to the experiment data and the results from other multi-dimensional system codes for the ECC delivery flow.

• Journal of Institute of Control, Robotics and Systems
• /
• v.17 no.5
• /
• pp.436-443
• /
• 2011

Recognition of structures in urban environments is a fundamental ability for unmanned ground vehicles. In this paper we propose the geometrical featured voxel which has not only 3-D coordinates but also the type of geometrical properties of point cloud. Instead of dealing with a huge amount of point cloud collected by range sensors in urban, the proposed voxel can efficiently represent and save 3-D urban structures without loss of geometrical properties. We also provide an urban structure classification algorithm by using the proposed voxel and machine learning techniques. The proposed method enables to recognize urban environments around unmanned ground vehicles quickly. In order to evaluate an ability of the proposed map representation and the urban structure classification algorithm, our vehicle equipped with the sensor system collected range data and pose data in campus and experimental results have been shown in this paper.