• Proceedings of the KIEE Conference
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• 2006.10b
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• pp.131-135
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• 2006

In this paper, a new estimation algorithm for the rotor speed for SRM drives is described. The algorithm is implemented by the binary observer. The stability and robustness of the binary observer for the parameter variations of the SRM are Proved by variable structure control theory. Variable speed control of the SRM is accomplished by the estimated speed. Experiment results verify that the MRAS observer is able to estimate the speed.

• Proceedings of the KIPE Conference
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• 1996.06a
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• pp.1-4
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• 1996

The purpose of this treatise is to estimate speed of an induction motor and realize a robust speed control system with estimated speed in field-weakening region. A speed estimation is based on Model Reference Adaptive System(MRAS) technique and two flux estimator are designed to be robust against parameter variation. The MRAS-based overall control scheme has been implemented on 7.5kW Spindle induction motor control system. And it is verified that the proposed control scheme is very stable and robust in field-weakening region.

• Proceedings of the KIEE Conference
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• 2004.07e
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• pp.33-36
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• 2004

In this paper, a new estimation algorithm for the rotor speed for SRM drives is described. The algorithm is implemented by the sliding mode observer. The stability and robustness of the sliding observer for the parameter variations of the SRM are proved by variable structure control theory. Variable speed control of the SRM is accomplished by the estimated speed. Experiment results verify that the sliding mode observer is able to estimate the speed.

• Proceedings of the KIEE Conference
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• 2005.10a
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• pp.161-164
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• 2005

In this paper, a new estimation algorithm for the rotor speed for SRM drives is described. The algorithm is implemented by the binary observer. The stability and robustness of the binary observer for the parameter variations of the SRM are proved by variable structure control theory. Variable speed control of the SRM is accomplished by the estimated speed. Experiment results verify that the binary observer is able to estimate the speed.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.05a
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• pp.1104-1109
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• 2002

High speed railroad noise is one of the main causes of environmental impact. An estimate of the relevant noise levels is usually required in order to evaluate the noise barrier and the anti-noise trailer. This paper introduce the test procedure and the estimate for HST noise. The aim of this is to measure, by means of a test, the level of acoustic pressure present during the passing of a KTX(Korea Train Express), in order to satisfy the contractual requirements and the noise criteria. A number of measurements are carried out in order to estimate noise impact by HST along test track.

• Proceedings of the KSME Conference
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• 2001.06b
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• pp.181-186
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• 2001

High speed railroad noise is one of the main causes of environmental impact. An estimate of the relevant noise levels is usually required in order to evaluate the noise barrier and the anti-noise trailer. This paper introduce the test procedure and the estimate for HST noise. The aim of this is to measure, by means of a test, the level of acoustic pressure present during the passing of a KTX(Korea Train Express), in order to satisfy the contractual requirements and the noise criteria. A number of measurements are carried out in order to estimate noise impact by HST along test track.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.41 no.4
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• pp.284-290
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• 2013

The authors propose a nonlinear unknown input observer to estimate the angular speed of a satellite and to detect faults of reaction wheels. Input values are necessary to estimate the angular speed. Therefore, estimation errors are inevitable if faults occur in actuators or reaction wheels. Unknown input observers are useful to estimate the states of a system without being affected by unknown faults. The authors have designed a nonlinear unknown input observer by using the SDRE method and verified the proposed observer via numerical simulations. In spite of various and simultaneous faults, we have estimated the states and detected faults exactly by the proposed nonlinear unknown input observer.

• Journal of the Korean Society for Precision Engineering
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• v.21 no.5
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• pp.99-105
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• 2004

Internet provides the useful method to monitor the current states of the machine tool no matter where a personnel monitors it. In this paper, a monitoring method of the torque of the machine tool's spindle induction motor using interne is suggested. To estimate the torque accurately, spindle driving system of an CNC lathe is divide into two parts, induction motor part and mechanical part attached to the induction motor spindle. Magnetizing current is calculated from the measured 3 phase currents without speed sensor used to estimate the torque generated by an induction motor. In mechanical part of the system, some of the torque is used to overcome friction and remaining torque is used to overcome cutting force. An equation to estimate friction torque is drawn as a function of cutting torque and rotation speed. Graphical programming is used to implement the suggested algorithm. to monitor the torque of an induction motor in real time and to make the estimated torque monitored on client computers. Torque of the spindle induction motor is well monitored on the client computers in about 3% error range under various cutting conditions.

• Journal of the Society of Naval Architects of Korea
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• v.43 no.1 s.145
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• pp.32-42
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• 2006

This study aims at establishing a technique for sailing yachts model tests with sailing condition. It is very important to estimate a ship's potential speed performance before building a real ship. Several methods are used to estimate a ship's potential speed performance such as using parent ship data, standard vessel chart and model test. Model test is the most precise among these options. In korea. model testing is widely used with general vessels but not with sailing yachts. Because sailing yachts are propelled with heeling and leeway. using the wind. another method is needed to estimate their speed. The new model test. which is different from tests for upright general vessels, is in a great demand. In this paper. we describe a test method for the sailing yacht model test. based on Masuyama's equation of motion. And we describe choosing scale ratio. production process and materials of the model. Also. various ways of measuring instruments. attaching jigs and adjusting calibration are described so that they can be utilized as useful data for model testing.

• Transactions of the Korean Society of Automotive Engineers
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• v.15 no.5
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• pp.174-179
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• 2007

The transient brake time or distance is one of very important factors to guess the vehicle speed to inspect an automobile accident. But, it is usual that the vehicle speed is estimated by using only skid mark without considering the transient brake distance. Deceleration and the friction coefficients of tire and road surface play an important role in calculating the brake distance. In this paper, a scheme is presented to estimate more accurate automobile speed. The scheme contains the effect of the transient brake distance on the speed. Experiment was carried out on the asphalt, unpacked road to get relationships between the speeds and the skid mark distances, and to get the transient brake time. The experimental results were utilized to construct the equation to approximate more realistic vehicle speeds.