• Proceedings of the IEEK Conference
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• 2000.06d
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• pp.62-65
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• 2000

In order to reconstruct a high resolution image, it is important to reconstruct frames from fields. A number of approaches have been developed in making frames. In this paper, we propose a new deinterlacing algorithm based on local motion compensation, which is performed based on statistical property. The proposed algorithm achieves faster processing speed than block matching algorithm and higher resolution than inter-field interpolation. The effectiveness of the proposed algorithm is demonstrated experimentally.

• 제어로봇시스템학회:학술대회논문집
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• 1993.10b
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• pp.245-250
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• 1993

In this paper we propose two feedfroward unbalance compensation algorithms, they accommodate changes of rotor dynamics including rotating speed. The first one determine the compensating signals by identifying system dynamics successively. Whereas, the second one is more primitive like PID algorithm without identifying system dynamics.

• Journal of the Korean Institute of Telematics and Electronics D
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• v.35D no.8
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• pp.1-7
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• 1998

This paper reports a dispersion compensation technique to implement tje distortionless transmission line by satisfying the heaviside conditon. Because of the skin depth for aconductor, compensation condition is dependent on the freuqncy variation. For this reason, first, the resistance have been chaacterized in awide range of frequencies, and then found the effective conductivity of the substrate which satisfied the heaviside condition. The phase velocity and the characteristics impedance are prresented nearly constant over a wideband frequency range.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.32 no.1
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• pp.59-66
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• 1996

This paper considers robust stability and transient behavior of the Two - Degree - of - Freedom(2DOF) servosystem. A class of uncertainties allowed in the plant model is obtained, to which the servosystem is robustly stable for any gain of the integral compensator. This result implies that if the plant uncertainty is the allowable set defined by the condition, a high - gain compensation can be carried out preserving stability to achieve a high - speed tracking response. The transient behavior attainable by the limit of the high - gain compensation is calculated using the singular perturbation approach.

• Journal of Power Electronics
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• v.14 no.1
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• pp.125-134
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• 2014

This paper presents a robust and speed-sensorless stator flux estimation for induction motor direct torque control. The proposed observer is based on sliding mode approach. Stator electrical equations are used in the rotor orientation reference frame to eliminate the observer dependence on rotor speed. Lyapunov's concept for systems stability is adopted to confine the observer gain. Furthermore, the sensitivity of the observer to parameter mismatch is recovered with an adaptation technique. The nonlinearities of the pulse width modulation voltage source inverter are estimated and compensated to enhance stability at low speeds. Therefore, a new method based on the model reference adaptive system is proposed. Simulation and experimental results are shown to verify the feasibility and effectiveness of the proposed algorithms.

• Proceedings of the KIEE Conference
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• 1991.11a
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• pp.140-143
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• 1991

This paper describes a compensation method for the rotor resistance variation of induction machines in speed sensor-less vector control system using MRAS(model reference adaptive system). In case of rotor resistance variation, the analysis of the conventional speed sensor-less vector control system using MRAS is presented and the compensation method for rotor resistance variation using Fuzzy logic is proposed. In order to confirm the performance of the proposed algorithm, computer simulation is performed.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2001.04a
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• pp.71-73
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• 2001

The requirements for higher productivity call for high speed of the machine tool axes. Iron core type linear DC motor is growly accepted for a viable candidate of the high speed machine tool feed unit. LDM, however, has inherent disturbance force components: cogging and force ripple. These disturbance force directly affects the carrage tracking accuracy and must be eliminated or reduced. Reducing motor ripple, this paper adapted the feed forward compensation method. Experiments carried out on the linear motor test setup show that this compensation method is usable in order to reduce the motor ripple.

• International Journal of Precision Engineering and Manufacturing
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• v.6 no.1
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• pp.31-35
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• 2005

Higher productivity requires high-speed motion of machine tool axes. The iron core linear DC motor (LDM) is widely accepted as a viable candidate for high-speed machine tool feed unit. LDM, however, has two inherent disturbance force components, namely cogging and thrust force ripple. These disturbance forces directly affect the tracking accuracy of the feeding system and must be eliminated or reduced. In order to reduce motor ripple, this research adapted the feedforward compensation method and neural network control. Experiments carried out with the linear motor test setup show that these control methods are effective in reducing motor ripple.

• Journal of Power System Engineering
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• v.19 no.4
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• pp.89-96
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• 2015

This paper investigates some strategies to overcome the chattering problem of the conventional sliding mode observer (SMO) and to improve the rotor position estimation performance for full range sensorless control of a PMSM. An adaptive observer gain based on the Lyapunov's stability criterion and a cascade low pass filter with advanced phase delay compensation were proposed to reduce the chattering problem and to strengthen the filtering capability of the SMO. Several cases studies through experiments were carried out to confirm conventional SMO's problems and effectiveness of the proposed strategies. The experimental results show that the proposed method gives precise estimation on speed and rotor position when the motor rotates on 2% of its rated speed.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2004.10a
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• pp.358-362
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• 2004

Higher productivity requires high-speed motion of machine tool axes. The iron core linear DC motor (LDM) is widely accepted as a viable candidate for high-speed machine tool feed unit. LDM, however, has two inherent disturbance force components, namely cogging and thrust force ripple. These disturbance forces directly affect the tracking accuracy of the feeding system and must be eliminated or reduced. In order to reduce motor ripple, this research adapted the feedforward compensation method and neural network control. Experiments carried out with the linear motor test setup show that these control methods are effective in reducing motor ripple.