• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.138-138
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• 2000

In this paper, a methodology for designing a controller based on inverse dynamics for speed control of DC motors is presented. The proposed controller consists of a prefilter, the inverse dynamic model of a system and a fuzzy logic controller. The prefilter prevents high frequency effects from the inverse dynamic model. The model of the system is characterized by a nonlinear equation with coulomb friction. The fuzzy logic controller regulates the error between the set-point and the system output which may be caused by disturbances and it simultaneously traces the change o( the reference input. The parameters of the model are estimated by a genetic a]gorithm. An experimental work on a DC motor system is carried out to illustrate the performance of the proposed controller

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.05a
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• pp.842-847
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• 2002

One of the challenging problems with bicycle simulators is to deal with the inherent unstable bicycle dynamics that is coupled with rider's motion. For the bicycle dynamics calculation and the real time simulation, it is necessary to identify the control inputs from the rider as well as the virtual environments. The six control forces of the Stewart platform-based motion system are used for estimation of the rider's action force, which is one of the important control inputs, but of which the direct measurement is impractical. For the effective estimation of the rider's action force, the dynamics model of the motion system is derived incorporated with both analytical and experimental methods and the sliding mode controller with perturbation estimation is developed.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.10a
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• pp.624-627
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• 2002

Experimental study showed that the existing mathematical model doesn't fully describe the lateral motion of a moving web fur different operating conditions. So, a physically interpretable model of lateral motion of a moving web in a typical web guidance system, operated at Konkuk Univ., was developed using the system identification technique. A well-known Least Square Method based on ARX model was used for the system identification. Lateral displacement of the web was measured at the exit of each span by infrared sensors. The model obtained from identifying a linear time-invariant system for a typical operating condition yields an improved prediction capability of the lateral dynamics of the moving web compared to other mathematical models proposed in literature.

• International Journal of Automotive Technology
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• v.7 no.2
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• pp.121-128
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• 2006

The interaction between adherent molecules and gas molecules was modeled in the molecular scale and simulated by the molecular dynamics method in order to understand evaporation and removal processes of adherent molecules on metallic surface using high temperature gas flow. Methanol molecules were chosen as adherent molecules to investigate effects of adhesion quantity and gas molecular collisions because the industrial oil has too complex structures of fatty acid. Effects of adherent quantity, gas temperature, surface temperature and adhesion strength for the evaporation rate of adherent molecules and the molecular removal mechanism were investigated and discussed in the present study. Evaporation and removal rates of adherent molecules from metallic surface calculated by the molecular dynamics method showed the similar dependence on the surface temperature shown in the experimental results.

• Proceeding of EDISON Challenge
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• 2015.03a
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• pp.163-166
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• 2015

Intramolecular energy migration in a cyclic porphyrin array is spontaneous transfer of energy from one excited site to another. Since the efficiency of energy migration is inversely proportional to distance, the energy migration is occurred on their adjacent sites more often than distant ones. Therefore, the energy migration in the cyclic porphyrin array is largely dependent on their conformational characters. However, evaluation of conformational information by means of experimental tools is ambiguous since their limited resolution. In this work, we calculate the internal angle and distance distributions of cyclic porphyrin arrays using molecular dynamics simulations to obtain conformational information. To evaluate the angle and distance distributions respect to molecular size, we constructed molecules with n porphyrin dimers (n=1,3,7) in implicit solvent environment. Performing molecular dynamics simulations, we modulated alkyl groups to investigate additional conformational effects of the system.

• Journal of Information Display
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• v.5 no.1
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• pp.34-40
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• 2004

Time resolved infrared IR absorption spectroscopy is carried out to investigate the dynamics of electric field induced reorientation of the biphenyl molecular core and alkyl tail sub-fragments of the nematic liquid crystal 5CB (4-pentyl-4-cyano-biphenyl). The planar to homeotropic transition for high pre-tilt planar aligned cells, is studied for switching times ranging from 200 ${\mu}sec$ down to 80 ${\mu}sec$, the latter a factor of 1000 times faster than any previous nematic IR study. The reorientation rates of the core and tail are found to be the same to within experimental error and scale inversely with applied field squared, as expected for the balance of field and viscous torques. Thus any molecular conformation change during switching must relax on a shorter time scale. A simple model shows that no substantial differences exist between the reorientational dynamics of the tails and cores on the time scales longer than on the order of 10 ${\mu}s$.

• Nuclear Engineering and Technology
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• v.41 no.10
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• pp.1293-1306
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• 2009

In this paper, an infinite impulse response locally recurrent neural network (IIR-LRNN) is employed for modelling the dynamics of the Lead Bismuth Eutectic eXperimental Accelerator Driven System (LBE-XADS). The network is trained by recursive back-propagation (RBP) and its ability in estimating transients is tested under various conditions. The results demonstrate the robustness of the locally recurrent scheme in the reconstruction of complex nonlinear dynamic relationships.

• Clean Technology
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• v.8 no.2
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• pp.93-99
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• 2002

Adsorption dynamics for toluene and trichloroethylene with an isothermal fixed bed of activated carbon fiber were investigated. Equilibrium isotherms were measured by a static method for toluene and trichloroethylene onto activated carbon fiber at temperatures of 298, 323, and 348 K and pressure up to 3 kPa for toluene and 6 kPa for trichloroethylene, respectively. These results were correlated by the Toth equation. And dynamic experiments in an isothermal condition of 298 K were examined. Breakthrough curves reflected the effects of the experimental variables such as partial pressures for adsorbate and interstitial bulk velocities of gas flow. To present the column dynamics, a dynamic model based on the linear driving force (LDF) mass transfer model was applied.

• Bulletin of the Korean Chemical Society
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• v.34 no.10
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• pp.2931-2936
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• 2013

This paper presents results for the calculation of transport properties of noble gases (He, Ne, Ar, Kr, and Xe) at 273.15 K and 1.00 atm using equilibrium molecular dynamics (EMD) simulations through a Lennard-Jones (LJ) intermolecular potential. We have utilized the revised Green-Kubo formulas for the stress (SAC) and the heat-flux auto-correlation (HFAC) functions to estimate the viscosities (${\eta}$) and thermal conductivities (${\lambda}$) of noble gases. The original Green-Kubo formula was employed for diffusion coefficients (D). The results for transport properties (D, ${\eta}$, and ${\lambda}$) of noble gases at 273.15 and 1.00 atm obtained from our EMD simulations are in a good agreement with the rigorous results of the kinetic theory and the experimental data. The radial distribution functions, mean square displacements, and velocity auto-correlation functions of noble gases are remarkably different from those of liquid argon at 94.4 K and 1.374 $g/cm^3$.

• International Journal of Naval Architecture and Ocean Engineering
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• v.7 no.1
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• pp.41-55
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• 2015

This study is proposed a new hybrid mount having a moving-magnet type electromagnetic actuator to reduce the vibration transmitted from naval shipboard equipment to the structure of the ship's hull. Optimal design specifications are determined through experimental analysis. The detailed design of the hybrid mount is determined through several design steps with electromagnetic numerical analysis using Maxwell Software(S/W). The hybrid mount that combines a rubber mount and an electromagnetic actuator has a fail-safe function for shock resistance. The mount is fabricated and tested using a universal testing machine to evaluate the design specifications. Finally, numerical simulation of the hybrid mount is performed to confirm control performance and applicability.