• The Transactions of the Korean Institute of Electrical Engineers D
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• v.50 no.9
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• pp.423-429
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• 2001

This paper proposes adaptive impedance control algorithm using fuzzy inference when robot contacts with its environments. The characteristics of the adaptive impedance controller is to adapt with parametric uncertainty and nonlinear conditions. The control algorithm is to join impedance controller with fuzzy inference engine. The proposed control method overcomes the problem of impedance controller using gain-tuning algorithm of fuzzy inference engine. We implemented an experimental set-up consisting of environment-generated one-link robot system and DSP system for controller development. We apply the adaptive fuzzy impedance controller to one-link root system, and it shows the good performance on regulating the interactive force in case of contacting with arbitrary environment.

• Smart Structures and Systems
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• v.30 no.5
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• pp.463-477
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• 2022

In this paper, a hybrid vibration-impedance-based damage monitoring approach is experimentally evaluated for prestressed concrete (PSC) structures with local strand breakage. Firstly, the hybrid monitoring scheme is designed to alert damage occurrence from changes in vibration characteristics and to localize strand breakage from changes in impedance signatures. Secondly, a full-scale PSC anchorage is experimented to measure global vibration responses and local impedance responses under a sequence of simulated strand-breakage events. Finally, the measured data are analyzed using the hybrid monitoring framework. The change of structural condition (i.e., damage extent) induced by the local strand breakage is estimated by changes in a few natural frequencies obtained from a few accelerometers in the structure. The damaged strand is locally identified by tomography analysis of impedance features measured via an array of PZT (lead-zirconate-titanate) sensors mounted on the anchorage. Experimental results demonstrate that the strand breakage in the PSC structure can be accurately assessed by using the combined vibration and impedance features.

• Journal of information and communication convergence engineering
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• v.7 no.2
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• pp.113-118
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• 2009

This paper is about design broadband impedance matching circuit for Coupler to improve power transfer efficiency in the power line communication (PLC) system. The Tchebycheff gain function algorithm is represented to design broadband matching circuit. A practical PLC Coupler impedance matching circuit is designed, and the characteristics for S11 and S21 of PLC coupler are enhanced comparing with unmatched one. This is done by maximizing the power transfer gain from modem to the load.

• Journal of information and communication convergence engineering
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• v.8 no.3
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• pp.258-262
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• 2010

This paper represents design broadband impedance matching circuit for Coupler to improve power transfer efficiency in the broadband power line communication(BPLC) systems. The Butterworth gain function equalizer is used to design broadband matching circuit. A practical PLC Coupler impedance matching circuit is designed, and the characteristics for S11 and S21 of PLC Coupler are enhanced comparing with unmatched one. This is done by maximizing the power transfer gain from modem to the load.

• Proceedings of the KOSOMBE Conference
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• v.1991 no.11
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• pp.98-100
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• 1991

We studied the characteristics of the compound electrode and found that the compound electrode provides the four-electrode method in a compact form. We developed a new method of measuring the skin impedance using simple electrodes at low frequencies. At high frequencies where the effect of internal tissue impedance is not negligible, we used the compensation method using compound electrodes since they measure the voltage right under the skin. At 50 kHz, we measured the real part of the skin impedance of less than $80\;{\Omega}$ on the thorax.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2003.11a
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• pp.33-44
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• 2003

This paper introduces attempts to obtain the'representative'characteristics of the apparent mass and mechanical impedance of seated Korean subjects under vertical vibration. Individual responses of the apparent mass and driving-point mechanical impedance obtained from forty-one Korean subjects are illustrated. Four kinds of vibration levels and three different sitting postures are selected to collect the responses of each subject. Those individual responses are used to estimate the 'mean' mechanical impedance, which may be expected to be a representative model to Korean subjects. Several interesting features of the estimated mechanical impedance are suggested and compared to those of ISO 5982.

• 전기의세계
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• v.14 no.1
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• pp.26-34
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• 1965

The radiation patterns and impedance of the half wave solt on the wide side of rectangular wave guide are analyzed. The measuring methods and procedures are described. And that the experimental data of the pattern and impedance of the slot are presented which are consistent with the theoretical values. The causes of error are also considered and are believed to be tolerable for the pattern and input impedance measurements. The usefulness of the slot antenna tested are also described.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.60 no.4
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• pp.267-271
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• 2011

The insulating characteristics and temperature rise behaviors of porcelain suspension insulators were investigated. The testing insulators had used in the distribution systems normally and were sampled. Firstly, leakage current was measured and its impedance was calculated. The leakage current of good insulators is 0.2 mA and its impedance is 66 $M{\Omega}$. The worse insulators have lower impedance and the insulators having below 15 $M{\Omega}$ take place flashover at the high frequency voltage flashover test. Secondly, the temperature rise characteristics were analyzed depending on leakage current and its impedance. Surface temperature of insulators was measured for 30 minutes and until its saturation after voltage was applied. The temperature rise of insulators having 15 $M{\Omega}$ is about $14.5^{\circ}C$ above the ambient temperature. Lastly, the heating behaviors of 3 insulators in a string was analyzed. Any insulator in the string does not generate heat so far as it has at least one sound insulator. On the other hand, all the insulators in the string are bad if the string have any heating insulator.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1997.04a
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• pp.35-41
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• 1997

Viscoelastic materials shows the characteristics of elasticity and viscosity. Unlike metals which show negligible damping value, the damping characteristics of viscoelastic materials like rubber mounts is very important in the analysis of the dynamic system. So there has been a great interest in measuring the damping characteristics of viscoelastic materials. There are two kinds of methods which the damping characteristics can be measured. One is the resonant method where loss factor can be measured only in the resonant frequency. The other is the nonresonant method which is characterized by the impedance method are introduced. The impedance test results, the loss factor by the impedance method are compared to the results of the resonant method and recommendations in the experimental setup are suggested.

• Proceedings of the IEEK Conference
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• 2002.07a
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• pp.440-442
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• 2002

The electrical characteristics of biologically active points (BAPs) compared with those of the surrounding human skins are studied. And we confirm that BAPs have lower resistance and higher capacitance than the surrounding skins do. We also find that BAPs have higher characteristic frequency than surrounding skins and the impedance spectra of BAPs sometimes have two semicircles on the complex impedance plane. We propose the skin impedance model that is proper to the BAPs and this circuit describes our experimental results sufficiently well.