• 제어로봇시스템학회논문지
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• 제20권12호
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• pp.1284-1289
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• 2014

In this Paper, outdoor position estimation system was implemented using GPS (Global Positioning System) and INS (Inertial Navigation System). GPS position information has lots of errors by interference from obstacles and weather, the surrounding environment. To reduce these errors, multiple GPS system is used. Also, the Discrete Wavelet Transforms was applied to INS data for compensation of its error. In this paper, position estimation of the mobile robot in the straight line is conducted by EKF (Extended Kalman Filter). However, curve running position estimation is less accurate than straight line due to phase change in rotation. The curve is recognized through the rate of change in heading angle and the position estimation precision of the initial curve was improved by UPF (Unscented Particle Filter). In the case of UPF, if the number of particle is so many that big memory gets size is needed and processing speed becomes late. So, it only used the position estimation in the initial curve. Thereafter, the position of mobile robot in curve is estimated through switching from UPF to EKF again. Through the experiments, we verify the superiority of the system and make a conclusion.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2000년도 추계종합학술대회 논문집(4)
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• pp.167-170
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• 2000

In this paper, we present a fast algorithm for the motion estimation using the efficient selection of an initial search position. In the method, we select the initial search position using the motion vector from the subsmpled images, the predicted motion vector from the neighbor blocks, and the (0,0) motion vector. While searching the candidate blocks, we use the spiral search pattern with the successive elimination algorithm(SEA) and the partial distortion elimination(PDE). The experiment results show that the complexity of the proposed algorithm is about 2∼3 times faster than the three-step search(TSS) with the PSNR loss of just 0.05［dB］∼0.1［dB］ than the full search algorithm PSNR. The search complexity can be reduced with quite a few PSNR loss by controling the number of the depth in the spiral search pattern.

• International Journal of Ocean System Engineering
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• 제1권3호
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• pp.165-170
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• 2011

In this paper, for the accurate estimation of the position and orientation of the UUV (unmanned underwater vehicle), an AHRS (Attitude Heading Reference System) was developed using the IMU (inertial measurement unit) sensor which provides information on acceleration and orientation in the object coordinate and the initial alignment algorithm and the E-KF (extended Kalman Filter). The initial position and orientation of the UUV are estimated using the initial alignment algorithm with 3-axis acceleration and geomagnetic information of the IMU sensor. The position and orientation of the UUV are estimated using the AHRS composed of 3-axis acceleration, velocity, and geomagnetic information and the E-KF. For the performance test of the orientation estimation of the AHRS, a testbed using IMU sensor(ADIS16405) and DSP28335 coded with an E-KF algorithm was developed and its performance was verified through tests.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2007년도 하계학술대회 논문집
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• pp.328-330
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• 2007

This paper deals with the estimation method on the initial pole position of a z-axis permanent magnet linear synchronous motor(PMLSM) without magnetic pole sensors such as Hall sensors. The proposed method takes account of the z-axis conditions such as the gravitational force and also the load conditions. The algorithm consists of two steps. The first step is to estimate the initial q-axis approximately by monitoring the movements at predefined different test q-axes. The second step is to estimate the real q-axis as accurately as possible based on the results at three different test q-axes. Experimental results on the z-axis PMLSM show good estimation characteristics of the proposed method.

• 전기전자학회논문지
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• 제23권2호
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• pp.622-627
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• 2019

본 논문에서는 비대칭 공극을 갖는 단상 영구자석 동기 전동기의 센서리스 운전을 위한 초기 회전자 위치 검출 알고리즘을 제안한다. 일반적인 센서리스 운전 기법 중 역기전력 기반의 센서리스 제어는 영속 및 저속운전에서 역기전력 정보를 추정하기 어렵다. 이를 위해 오픈 루프 기동 기법이 필수적으로 요구되고 일정한 방향으로의 회전을 위해서는 회전자의 초기 위치 검출이 반드시 필요하다. 본 논문에서는 단상 영구자석 동기 전동기의 자기적 특성을 이용하여 고주파 전압 주입 신호에 옵셋 전압을 추가하여 회전자 자극을 검출하는 기법을 제안한다. 다수의 실험 결과를 통하여 제안된 알고리즘의 유효성과 유용성을 검증하였다.

• 전기학회논문지
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• 제60권10호
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• pp.1915-1923
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• 2011

For automated guidance control of a magnetically guided-all wheel steered vehicle, it is necessary to have information about position and orientation of the vehicle, and deviations from the reference path in real time. The magnet reference system considered here consists of three magnetic sensors mounted on the vehicle and magnetic markers, which are non-equidistantly buried in the road. This paper presents an observer to estimate such position and orientation at the center of gravity of the vehicle. This algorithm is based on the simple kinematic model of vehicle and uses the data of wheel velocity, steering angle, and the discrete measurements of marker positions. Since this algorithm requires the exact values of initial states, we have also proposed an algorithm of determining the initial position and orientation from the 16 successive magnet pole data, which are given by the magnetic measurement system(MMS). The proposed algorithm is capable of continuing to estimate for the case that the magnetic sensor fail to measure up to three successive magnets. It is shown through experimental data that the proposed algorithm works well within permissible error range.

• 한국항공우주학회지
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• 제36권7호
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• pp.680-687
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• 2008

본 논문에서는 광학방식 헤드 트랙커를 위한 맵 생성 알고리즘과 초기자세 추정기법을 제안한다. 제안한 광학방식 헤드 트랙커는 적외선 스테레오 카메라와 특징점으로 사용되는 적외선 다이오드가 부착된 헬멧으로 구성된다. 광학방식 헤드 트랙커의 경우 발광된 특징점의 중심점을 추적하여 조종사 머리의 자세 및 위치를 추정하기 때문에 이를 고려한 특징점의 정확한 위치정보가 요구된다. 제안한 맵 생성 알고리즘은 적외선 다이오드의 방사 형태를 고려하여 정밀한 특징점의 위치 정보가 포함된 맵 데이터와 머리 좌표계를 생성한다. 또한 초기자세 추정 기법은 헬멧에 부착된 특징점의 패턴을 이용하여 카메라와 머리 사이의 초기 자세와 위치를 빠르게 추정하며 이를 바탕으로 동체인 전투기를 기준으로 하는 머리 움직임을 정확하게 추정할 수 있다.

• 대한전기학회논문지:시스템및제어부문D
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• 제54권1호
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• pp.26-32
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• 2005

Rotor position information is essential in the operation of the switched reluctance motor(SRM) drive for generation the phase current switching signals. When an incremental encoder is used as a rotor position sensor, the initial rotor position can not be detected. Some sensorless rotor position estimation methods also have the same problem. In these systems, to initially align the rotor, the forced alignment method has a delay and reverse rotation before the motor can start. Therefore it can not be acceptable for unidirectional drive systems. So the forced alignment method is not desirable in all drive systems and the research on the SRM drives should be directed to a system without rotor alignment. In this paper, a new detection method of initial rotor position using the rate of change of current is suggested. Firstly, di/dt versus θ/sub R/ reference table, which is the relation between the rate of change of current and rotor position, is generated and then the squared Euclidean distance method is used to estimate the rotor position based on the table. The simulated and experimental results are presented demonstrating the feasibility and accuracy of this method.

• Journal of Power Electronics
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• 제10권4호
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• pp.396-404
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• 2010

This paper presents simple schemes used to estimate the initial rotor position and the d- and q-axis inductances for effective Maximum Torque per Ampere (MTPA) operation in a wind-power system using an IPMSM (Interior Permanent Magnet Synchronous Machine). An IPMSM essentially requires an exact coordinate transformation and accurate inductance values to use a reluctance torque caused by the saliency characteristic. In the proposed high-frequency voltage testing method, there is no voltage drop caused by the resistance and the electromotive force. The initial rotor position and the inductance can be measured through an analysis of the stator current without turning the rotor. The experimental results are presented in order to illustrate the feasibility of the proposed method.

• Journal of Power Electronics
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• 제11권6호
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• pp.856-863
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• 2011

In this paper a novel method of the Ant Colony Optimization algorithm for rotor position estimation in Switched Reluctance Motors is presented. The data provided by the initial assumptions is one of the important aspects used to solve the problems relative to an Ant Colony algorithm. Considering the nature of a real ant colony, it was found that the ants have no primary data for deducing which is the shortest path in their initial iteration. They also do not have the ability to see the food sources at a distance. According to this point of view, a novel method is presented in which the rotor pole position relative to the corresponding stator pole in a switched reluctance motor is estimated with high accuracy using the active and inactive phase parameters. This new method gives acceptable results such as a desirable convergence together with an optimized and stable response. To the best knowledge of the authors, such an analysis has not been carried out previously.