• Journal of the Korean Society for Heat Treatment
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• v.36 no.5
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• pp.311-317
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• 2023

An autofilter is a device that removes impurities contained in heavy fuel oil used in diesel engines of ships or power plants, and also automatically removes impurities accumulated in the filter through a reverse washing function. The reducer-integrated motor serves to rotate the filter at low speed to enable reverse automatic cleaning in the autofilter device. To achieve a low speed of 0.65 to 0.75 rpm in a reducer-integrated motor, a small motor that can operate at 97rpm at a rated voltage of 110 V and 112.5 rpm at 220 V is required. Additionally, a large gear ratio of 1/150 is required. To ensure the durability and reliability of these reducers, the strength of the gear must be evaluated at the design stage. In general, there is a limit to evaluating the stress and strain state according to the vibration characteristics acting on each gear in the driving state of the reducer through quasi-static analysis. Therefore, in this study, the operation characteristics of the auto filter's reducer-integrated motor were first analyzed using the rigid body dynamics analysis method. Then, this rigid body dynamics analysis model was extended to a flexible multibody dynamics analysis model to analyze the stress and strain states acting on each gear and evaluate the design feasibility of the gear.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.64 no.5
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• pp.739-745
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• 2015

In this paper, a flexible wireless power receiving system is proposed for wearable device applications. The proposed system is designed with printable component configuration to be integrable to textile material. While the defected ground structures(DGSs) are utilized for planar printable filter designs, direct impedance matching technique is considered for flexible circuit performance. The proposed system has been implemented on a flexible substrate with a thickness of 5 mils, and experimented for power conversion efficiencies and converted voltages. In order to evaluate the hardware flexibility, the system performance are measured a bended circuit board at a radius of curvature of 5 cm. The system performance is analyzed for the degradation due to the curvature. The proposed system has shown the excellent capability of far-field wireless power transfer systems in flexible device environments.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.40 no.3
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• pp.18-24
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• 2003

The resonator using two layer microstrip structure was proposed and the bandpass filter was designed using this resonator in this paper. The proposed resonator structure is constructed by placing a U-shape of resonator in the first layer and then placing a broadside coupling strip in the second layer just above of the U-shape of resonator's edge part. Because these structure has various design parameters than general single layer coupled line structure, filter design is more flexible. In this paper, the narrow band filter was designed using multi-layer structure that had been applied to broadband filter because it's high coupling nature. The filter was designed to have 4MHz center frequency and 3 % fractional bandwidth, and finally confirmed that can be realizable narrow band filter by using multi-layer structure through fabrication and measurement.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2002.11a
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• pp.339-342
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• 2002

In the industrial motor drive system which is composed of a motor and load connected with a flexible shaft, a torsional vibration is often generated because of the elastic elements in torque transmission. To solve this problem H$_{\infty}$ controller was designed. In this paper, H$_{\infty}$ control of 2-mass system using H$_{\infty}$ filter for compensating shaft torque is proposed. Pole-zero maps show the validity of proposed controller.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.130.5-130
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• 2001

This paper presents a discrete-time sliding mode control method for linear time-invariant systems with matched uncertainties. In this paper, we suggest a method of adding a command generator using input shaping filter to a discrete-time sliding mode controller. We design the number of steps required to reach the sliding layer and the magnitude of a control input, respectively using the shaping filter. Therefore we can minimize the excitation of the resonance mode and increase the tracking performance of a system. Simulation results are included to show its effectiveness.

• 제어로봇시스템학회:학술대회논문집
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• 1992.10b
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• pp.187-192
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• 1992

There are several potential error sources that can affect the estimation of the position of an object using combined vision and acceleration measurements. Two of the major sources, accelerometer dynamics and random noise in both sensor outputs, are considered. Using a second-order model, the errors introduced by the accelerometer dynamics are reduced by the smaller value of damping ratio and larger value of natural frequency. A Kalman filter approach was developed to minimize the influence of random errors on the position estimate. Experimental results for the end-point movement of a flexible beam confirmed the efficacy of the Kalman filter algorithm.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.20 no.11
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• pp.3549-3559
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• 1996

In this study, the effect of parameter and modal filter errors on the vibration control characteristics of flexible structures is analyzed for IMSC ( Independent Modal Space Control). If the control force is designed on the basis of the mathematical model with the parameter and modal filter errors, the closed-loop performance of the vibration control system will be degraded depending on the magnitude of the errors. An asymptotic stability condition of the system with parameter and modal filter errors has more significant effect on the stability condition of the system with parameter and modal filter errors has been drived using Lyapunov approach. It has been found that modal filter error has more significant effect on the stability of closed-loop system than parameter error does. The extent of the response deviation of the closed-loop system is also derived and evaluated using operator thchniques.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.2A
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• pp.167-173
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• 2008

In this paper, the flexible narrow bandpass filters (BPFs) with ${\lambda}$g/4 short and ${\lambda}$g/2 open stubs by microstrip line on duroid substrate are suggested. These BPFs with narrow bandwidth show flexible bandwidth with variation of the position of the stubs using the Qe (external quality factor) without changing the impedance value at microwave range. On the other hand, by replacing the series quarter-wavelength connecting lines with the equivalent T-shaped line of bandstop filter(BSF), the compact stub bandpass filter with harmonics suppression can be realized. The BPF with ${\lambda}$g/4 short stubs shows the insertion loss of 2.1 dB and the return loss of 18 dB and BPF with ${\lambda}$g/2 open stubs shows the insertion loss of 1.2 dB and the return loss of 21.9 dB at the center frequency of 5.8 GHz and the bandwidth of 10 %.

• Journal of the Korean Society for Precision Engineering
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• v.18 no.8
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• pp.79-86
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• 2001

A method for actively minimizing dynamic reaction forces in a flexible structure subject to persistent excitations is presented. One difficulty with the method, however, is that forces and moments do not converge as quickly as displacements in mathematical discretization of continuous systems, so a controller based on a truncated model of a continuous system can produce poor results. A technique using residual flexibility matrix is presented for correcting the truncated force representation. A controller designed for reaction force minimization, using the residual flexibility matrix, is applied to a model of a flexible structure, and the results are presented. Implications of various reaction force penalty combinations on the resulting control performance are also discussed.

• Educational Technology International
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• v.6 no.1
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• pp.65-79
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• 2005

In a widely distributed environment, many occasions arise when people need to filter informationwith email clients. The existing information agents such as Maxims and Message Assistant have capabilities of filtering email messages either by an autonomous agent or by user-defined rules. FlexMA, a variation of FAMES (Flexible Asynchronous Messaging System) is proposed as an information filtering agent. Agents in our system can be scaled up to adapt user's various demands by controlling messages delivered among heterogeneous email clients. Several functionalities are split into each agent in terms of component configuration with the addition of multiple agents'cooperation and negotiation. User-defined rules are collected and executed by these agents in a semi-autonomous manner. This paper demonstrates how this design is feasible in a flexible message system.