• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.18 no.9
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• pp.913-919
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• 2008

Dynamic characteristics of a wrist power transmission of an industrial robot are studied. The wrist power transmission has complex structure characteristics, because it is composed with several shafts and gear system. We used an analytical method to investigate the dynamic characteristics. An analytical model is a rigid model which is composed with masses and springs. Both bearing and gear contact model represent equivalent stiffness springs which are determined by the experiment. In order to investigate the dynamic tendency of the robot wrist power transmission, we simulate the analytical model. There is a dynamic analysis tool which is called the RecurDyn. To verify the analytic results, we experiment a signal analysis which is an overall noise level of the robot. By the parametric study of the element of the robot, we study an improvement method of dynamic characteristics.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.11b
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• pp.166-171
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• 2002

The transmission loss coefficient is very important acoustic property in parallel with absorption and acoustic impedance categorizing the acoustical materials, which can control the acoustical problems. At the same time, the transmission loss coefficient is a key parameter to choose the optimum material for the analysis of acoustical characteristics of material using SEA(Statistical Energy Analysis). In this paper, the transmission loss coefficient measurement system using 4-microphone impedance tube is proposed, based on the idea calculating the full transfer matrix of the acoustical sample to test. The theoretical background and measurement system are introduced, and finally the measurement results are verified.

• Journal of the Korean Society for Precision Engineering
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• v.18 no.9
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• pp.204-209
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• 2001

The finite element model for automotive muffler analysis is improved by modifying the boundary condition of outlet and the mesh of finite element model. The model minimizes the difference between transmission loss from analysis and that from experiment. Four different boundary conditions and the four types of finite element model are tested to find out the best one of those. From the case study it is verified that the bevel of transmission loss can be changed by the variation of radiation impedance value. Also the resonance or anti-resonance frequencies of transmission loss can be shifted by the variation of finite element mesh. An improved finite element model of muffler is proposed in consideration with the accuracy and the computing time of analysis.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.11a
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• pp.323.1-323
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• 2002

The transmission loss coefficient is very important acoustic property in parallel with absorption and acoustic impedance categorizing the acoustical materials, which can control the acoustical problems. At the same time, the transmission loss coefficient is a key parameter to choose the optimum material for the analysis of acoustical characteristics of material using SEA(Statistical Energy Analysis). In this paper, the transmission loss coefficient measurement system usiong 4-microphone impedance tube is proposed, based on the idea calculating the full transger matrix of the acoustical sample to test. The theoretical backgroung and measurement system are introduced, and finally the measurement results are verified.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2003.05a
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• pp.658-661
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• 2003

The transmission loss coefficient is very important acoustic property in parallel with absorption and acoustic impedance categorizing the acoustical materials, which can control the acoustical problems. At the same time, the transmission loss coefficient is a key parameter to choose the optimum material for the analysis of acoustical characteristics of material using SEA(Statistical Energy Analysis). In this paper, the transmission loss coefficient measurement system using 4-microphone impedance tube is proposed, based on the idea calculating the full transfer matrix of the acoustical sample to test. The theoretical background and measurement system are introduced, and finally the measurement results are verified.

• Proceedings of the KIEE Conference
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• 2004.05a
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• pp.65-67
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• 2004

Change of state of Channel between two wireless terminals which is caused by noise and multiple environmental conditions for happens frequently from the Wireles Network. So, When it is like that planning a wireless network protocol or performance analysis, it follows to change of state of time-varying channel and packet the analysis against a transmission efficiency is necessary. In this paper, analyzes transmission time of a packet and a packet in a time-varying and packet based Wireless Network. To reflecte the feature of the time-varying channel, we use a Signal Flow Graph model. From the model the mean of transmission time and the mean of queue length of the packet are analyzed in terms of the packet distribution function, the packet transmission service time, and the PER of the time-varying channel.

• Transactions of the Korean Society of Automotive Engineers
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• v.22 no.4
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• pp.89-97
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• 2014

As the digital control technologies in automotive industry have advanced, electronic control units(ECUs) play a key-role to improve system performance. Transmission control unit(TCU) is a shifting controller for automatic transmission of which major functions are to determine the shift and manage the shifting process considering the various sensor signal on transmission and driver's commands. As with any ECU in vehicle, TCU performs complex algorithms such as shift control, diagnostic and failsafe functions. However, firmware design analysis is hardly possible by the reverse engineering due to code protection. Transmission simulator is a hardware-in-the-loop simulator which enables TCU to work in normal mode by simulating the electrical signal of TCU interface. In this research, diagnosis and failsafe algorithm implemented on commercialized TCU is analyzed by using the transmission simulator that is developed for wheel loader construction vehicle. This paper gives various experimental results on the proportional solenoid current trajectories for different operating modes, error detection criterion and limphome mode gears for all the possible cases of clutch malfunction. The derived results for conventional TCU can be applied to the development of inherent TCU algorithms and the transmission simulator can also be utilized for the test of TCU to be developed.

• Journal of Power Electronics
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• v.19 no.1
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• pp.211-219
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• 2019

In magnetically coupled resonant (MCR) wireless power transfer (WPT) systems, the introduction of additional intermediate coils is an effective means of improving transmission characteristics, including output power and transmission efficiency, when the transmission distance is increased. However, the position of intermediate coils in practice influences system performance significantly. In this research, a three-coil MCR WPT system is adopted as an exemplification for determining how the spatial position of coils affects transmission characteristics. With use of the fundamental harmonic analysis method, an equivalent circuit model of the system is built to reveal the relationship between the output power, the transmission efficiency, and the spatial scales, including the axial, lateral, and angular misalignments of the intermediate and receiving coils. Three cases of transmission characteristics versus different spatial scales are evaluated. Results indicate that the system can achieve relatively stable transmission characteristics with deliberate adjustments in the position of the intermediate and receiving coils. A prototype of the three-coil MCR WPT system is built and analyzed, and the experimental results are consistent with those of the theoretical analysis.

• Earthquakes and Structures
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• v.17 no.6
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• pp.635-647
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• 2019

Tests and theoretical studies for seismic responses of a transmission tower-line system under coupled horizontal and tilt (CHT) ground motion were conducted. The method of obtaining the tilt component from seismic motion was based on comparisons from the Fourier spectrum of uncorrected seismic waves. The collected data were then applied in testing and theoretical analysis. Taking an actual transmission tower-line system as the prototype, shaking table tests of the scale model of a single transmission tower and towers-line systems under horizontal, tilt, and CHT ground motions were carried out. Dynamic equations under CHT ground motion were also derived. The additional P-∆ effect caused by tilt motion was considered as an equivalent horizontal lateral force, and it was added into the equations as the excitation. Test results were compared with the theoretical analysis and indicated some useful conclusions. First, the shaking table test results are consistent with the theoretical analysis from improved dynamic equations and proved its correctness. Second, the tilt component of ground motion has great influence on the seismic response of the transmission tower-line system, and the additional P-∆effect caused by the foundation tilt, not only increases the seismic response of the transmission tower-line system, but also leads to a remarkable asymmetric displacement effect. Third, for the tower-line system, transmission lines under ground motion weaken the horizontal displacement and acceleration responses of transmission towers. This weakening effect of transmission lines to the main structure, however, will be decreased with consideration of tilt component.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.5
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• pp.847-853
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• 2010

This paper describes switching surge analysis for reclosing decision in 345kV combined transmission line with XLPE power cable. Reclosing operation should be decided based on the detailed technical analysis in combined transmission line because this line includes power cable section which is week on insulation. Insulation of power cable can be breakdown at the week point in case of reclosing moment. Therefore the detailed analysis has to be carried out by considering several conditions such as length ratio of power cable section, arrestor, inserting resistance, charging rate, grounding resistance, etc.. On the other hand sheath voltage on IJ(Insulated Joint) is analyzed to check dangerous condition on cable cover. Analysis is performed by EMTP/ATP. Analysis results show that reclosing can be operated as the single line-to-ground fault occurs on overhead line in 345kV combined transmission line, if the inserting resistance is considered before the operation of main circuit breaker.