• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2006년도 하계종합학술대회
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• pp.1005-1006
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• 2006

This paper proposes a method of position estimating through compensating the autonomous mobile robot's noise. Proposed method is that estimated position error by modified Kalman filter method using neural network. We use a neural network for measurement noise covariance and system noise covariance. In order to verify the effectiveness of the proposed method, we performed experiments for position estimation. The results show that convergence and position error is reduced than the Kalman filter method.

• 전기학회논문지
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• 제62권6호
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• pp.756-761
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• 2013

This paper propose the new demodulation method that can detect resolver signal's peak at the time of position estimation when the position information is required during current controller period. The proposed method is performed in a synchronous demodulation way with exciting signal and also cover a capability which can compensate the lag element of exciting signal caused by the resolver's inductive component and filter circuit. This paper carried out the experiment to investigate the validity and performance of the suggested method by using the test board made up of DSP and demodulation circuit. The test results show that the proposed method is theoretically clear and work completely as expected from making sure of sampling resolver signal's peak at the time of position estimation. In addition, Software position tracking algorithm is executed with the demodulated signals generated by the suggested method and an exact position can be estimated.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2005년도 전력전자학술대회 논문집
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• pp.578-580
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• 2005

This paper proposes the algorithm for the initial pole-position estimation of a surface PM-LSM, which is carried out under the pseudo-position control with-out a pole sensor and is insensitive to the motor parameters. This algorithm is based on the principle that the initial pole-position is calculated by the reverse trigonometric-function using the two reference currents, which are informed from the speed controller. The effectiveness of the proposed algorithm is confirmed by the arithmetical analysis and the experiment. IPP is well estimated within a satisfied moving-distance and a shorter estimation taken-time even if large disturbance such as cogging and friction are existed.

• 한국수자원학회논문집
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• 제44권2호
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• pp.85-96
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• 2011

연최대수문량의 도시적 분석에 주로 이용되어 온 확률도시위치는 표본자료와 적정 확률분포형의 적합도를 표시하여 초과확률을 산정할 수 있도록 하며, 일부 적합도 검정에도 사용되기도 한다. 확률도시위치를 결정하는 도시위치공식은 오래 전부터 꾸준히 연구되어 왔는데, 특히 빈도해석에 널리 사용되는 GEV 분포에 대한 연구는 다른 분포형보다 더욱 활발히 이루어져 왔다. 본 연구에서는 GEV 분포에 적합한 도시위치공식을 추정하고자 GEV 분포의 순서통계량의 평균 개념을 이용하여 이론적 축소변량을 유도하였다. 또한 다양한 표본크기와 형상 매개변수와 연관이 있는 왜곡도 계수를 고려한 다양한 형태의 도시위치공식을 적용하고, 유전자 알고리즘을 적용하여 도시위치공식의 매개변수를 추정하였다. 유도된 도시위치공식의 정확성을 알아보기 위해 이론적 축소변량과 금회 유도된 도시위치공식을 포함한 다양한 도시위치공식에 의해 계산되는 축소변량 사이의 오차를 비교하였다. 그 결과, 본 연구에서 제안한 도시위치공식은 GEV 분포의 형상 매개변수가 -0.25~0.10의 범위를 가질 때 이론적 축소변량과 가장 작은 오차를 보이는 것으로 나타났다.

• 센서학회지
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• 제32권4호
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• pp.232-237
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• 2023

This paper presents a system for estimating the position of a magnet using a magnetic sensor. An algorithm is presented to analyze the waveform and output voltage values of the magnetic field generated at each position when the magnet moves and to estimate the position of the magnet based on the analyzed data. Here, the magnet is sufficiently small to be inserted into a blood vessel and has a micro-magnetic field of hundreds of nanoteslas owing to the small size and shape of the guide wire. In this study, a highly sensitive magneto-impedance (MI) sensor was used to detect these micro-magnetic fields. Nine MI sensors were arranged in a 3×3 configuration to detect a magnetic field that changes according to the position of the magnet through the MI sensor, and the voltage value output was polynomially regressed to specify a position value for each voltage value. The accuracy was confirmed by comparing the actual position value with the estimated position value by expanding it from a 1D straight line to a 3D space. Additionally, we could estimate the position of the magnet within a 3% error.

• Journal of Power Electronics
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• 제15권3호
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• pp.721-729
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• 2015

A sensorless control method was recently investigated in the robot and automation industry. This method can solve problems related to the rise of manufacturing costs and system volume. In a vector control method, the rotor position estimated in the sensorless control method is generally used. This study is based on a conventional full-order flux observer. The proposed full-order flux observer estimates both currents and fluxes. Estimated d- and q-axis currents and fluxes are used to estimate the rotor position. In selecting the gains, the proposed full-order flux observer substitutes gain k for the speed information in the denominator of the gain for fast convergence. Therefore, accurate speed control in a low-speed region can be obtained because gains do not influence the estimation of the rotor position. The stability of the proposed full-order flux observer is confirmed through a root-locus method, and the validity of the proposed observer is experimentally verified using a surface permanent-magnet synchronous motor.

• ETRI Journal
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• 제32권6호
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• pp.891-900
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• 2010

In this paper, a map-matching (MM) algorithm which combines an estimated position with digital road data is proposed. The presented algorithm using a virtual track is appropriate for a MEMS-based pedestrian dead reckoning (PDR) system, which can be used in mobile devices. Most of the previous MM algorithms are for car navigation systems and GPS-based navigation system, so existing MM algorithms are not appropriate for the pure DR-based pedestrian navigation system. The biggest problem of previous MM algorithms is that they cannot determine the correct road segment (link) due to the DR characteristics. In DR-based navigation system, the current position is propagated from the previous estimated position. This means that the MM result can be placed on a wrong link when MM algorithm fails to decide the correct link at once. It is a critical problem. Previous algorithms never overcome this problem because they did not consider pure DR characteristics. The MM algorithm using the virtual track is proposed to overcome this problem with improved accuracy. Performance of the proposed MM algorithm was verified by experiments.

• 한국생산제조학회지
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• 제19권1호
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• pp.15-25
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• 2010

The objective of this study is to investigate the optimal arrangement of cameras used for the robot's vision control scheme. The used robot's vision control scheme involves two estimation models, which are the parameter estimation and robot's joint angle estimation models. In order to perform this study, robot's working region is divided into three work spaces such as left, central and right spaces. Also, cameras are positioned on circular arcs with radius of 1.5m, 2.0m and 2.5m. Seven cameras are placed on each circular arc. For the experiment, nine cases of camera arrangement are selected in each robot's work space, and each case uses three cameras. Six parameters are estimated for each camera using the developed parameter estimation model in order to show the suitability of the vision system model in nine cases of each robot's work space. Finally, the robot's joint angles are estimated using the joint angle estimation model according to the arrangement of cameras for robot's point-position control. Thus, the effect of camera arrangement used for the robot's vision control scheme is shown for robot's point-position control experimentally.

• 한방재활의학과학회지
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• 제24권3호
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• pp.149-155
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• 2014

Objectives This study was designed to investigate the correlation between the difference of pelvic height and difference of gait balance. Methods 62 cases of patients who received treatment from January 2011 to March 2014 for abnormal postures were analyzed. Their difference of pelvic height were estimated by whole spine X-ray analysis and gait balance were estimated by Treadmill Gait Analysis system. The data were analyzed to find out correlation between difference of pelvic height and difference of gait balance, and correlation between the position of pelvic tilt and gait balance higher side. Pearson correlation and Chi-square analysis were used. Results Pelvic height heigher side were more left than right side, and gait balance higher side were also more left than right side. Difference of pelvic height and difference of gait balance had a positive linear relationship, but there was no significant correlation. The position of pelvic tilt had significant correlation with gait balance higher side. Conclusions The position of pelvic tilt had significant correlation with gait balance higher side and difference of pelvic height had no significant correlation with difference of gait balance.

• 전력전자학회논문지
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• 제18권6호
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• pp.523-529
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• 2013

A sensorless speed control of a permanent magnet synchronous motor(PMSM) which utilizes MRAS based scheme to estimate rotor speed and position is presented. Considering an error between real and estimated rotor position values, a state equation of PMSM in the synchronous d-q reference frame is represented. A state equation of model system which uses estimated speed and nominal parameter values is expressed. To minimize the errors between the derivatives of d-q axis currents of real and model system, MRAS based adaptation mechanisms for the estimation of rotor speed and position are derived. On the other hand, for the acceleration stage of motor just before the sensorless operation, an acceleration scheme using only d-axis current control is proposed. To show the validity of the proposed scheme, experimental works are carried out and evaluated. During acceleration stage, the acceleration scheme using only d-axis current command shows good acceleration performance and controlled current level. For the sensorless operation, at low speed (5% of rated speed), a good performance is observed.