• The Transactions of The Korean Institute of Electrical Engineers
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• v.62 no.6
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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.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.38 no.7
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• pp.693-701
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• 2010

In this paper, it is proposed that an attitude and position estimation algorithm based on a stereo camera system for a helmet tracker. Stereo camera system consists of two CCD camera, a helmet, infrared LEDs and a frame grabber. Fifteen infrared LEDs are feature points which are used to determine the attitude and position of the helmet. These features are arranged in triangle pattern with different distance on the helmet. Vision-based the attitude and position algorithm consists of feature segmentation, projective reconstruction, model indexing and attitude estimation. In this paper, the attitude estimation algorithm using UQ (Unit Quaternion) is proposed. The UQ guarantee that the rotation matrix is a unitary matrix. The performance of presented algorithm is verified by simulation and experiment.

• Journal of Electrical Engineering and Technology
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• v.11 no.4
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• pp.931-938
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• 2016

Application of vector control scheme for consumer products is enlarging to improve control performance. For the field-oriented control, accurate position detection is essential and generally requires expensive sensors. On the other hand, cost-reduction is important in home appliances, so that binary-type Hall-effect sensors are commonly used rather than using an expensive sensor such as an encoder. The control performance is directly influenced by the accuracy of the position information, and there exist non-uniformities related to Hall sensors in electrical and mechanical aspects, which result in distorted position information. Therefore, to get high-precision position information from low-resolution Hall sensors, this paper proposes a new position estimator consisting of a Kalman filter and feedforward compensation scheme, which generates a linearly changing position signal. The efficacy of the proposed scheme is verified by simulation and experimental results carried out with a 48-pole permanent magnet motor.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2001.10a
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• pp.204-208
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• 2001

Position control of the electro-hydraulic servo indexing system in a flexible forging machine was investigated Flexible forging machine forges an axial type workpiece in the radial direction as well as in the axial direction. The role of the indexing system is to rotate a workpiece fast and accurately to a desired position for continuous shaping. Since the inertia of a workpiece changes during each forging step, a control technique which is robust to inertia variation should be adopted to the position control of the workpiece. In this study, time delayed control technique is applied to the servo system. Time delayed control method does not depend on estimation of specific parameters. Rather, it depends on the direct estimation of a function representing the effect of uncertainties. Direct estimation is accomplished using time delay and the gathered information is used to cancel the unknown dynamics is accomplished using disturbances simultaneously. Experimental result show that the time delayed controller is robust to inertia variation of the load, and satisfactory performance on the sposition accuracy is obtained compared to the contentional feedback control.

• Journal of Electrical Engineering and Technology
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• v.12 no.3
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• pp.1166-1176
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• 2017

Estimation errors of the rotor speed and position in sensorless control systems of Permanent Magnet Synchronous Motors (PMSM) will lead to low efficiency and dynamic-performance degradation. In this paper, a parallel-type extended nonlinear observer incorporating the nominal parameters is constructed in the stator-fixed reference frame, with rotor position, speed, and the load torque simultaneously estimated. The stability of the extended nonlinear observer is analyzed using the indirect Lyapunov's method, and observer gains are selected according to the transfer functions of the speed and position estimators. Taking into account the parameter inaccuracies issue, explicit estimation error equations are derived based on the error dynamics of the closed-loop sensorless control system. An equivalent flux error is defined to represent the back Electromotive Force (EMF) error caused by the inaccurate motor parameters, and a compensation strategy is designed to suppress the estimation errors. The effectiveness of the proposed method has been validated through simulation and experimental results.

• Journal of Institute of Control, Robotics and Systems
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• v.14 no.8
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• pp.752-759
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• 2008

In this paper, we propose a high accurate geo-location system based on a single base station, where its location is obtained by Time-of-Arrival(ToA) and Direction-of-Arrival(DoA) of the radio signal. For estimating accurate ToA and DoA information, a MUltiple SIgnal Classification(MUSIC) is adopted. However, the estimation of ToA and DoA using MUSIC algorithm is a time-consuming process. The position tracking bias is occurred by the time delay caused by the estimation process. In order to mitigate the bias error, we propose the estimation method of the position tracking bias and compensate the location error produced by the time delay using the position tracking bias mitigation. For accurate self-localization of mobile robot, the Unscented Kalman Filter(UKF) with position tracking bias is applied. The simulation results show the efficiency and accuracy of the proposed geo-location system and the enhanced performance when the Unscented Kalman Filter is adopted for mobile robot application.

• The Journal of the Korea institute of electronic communication sciences
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• v.6 no.5
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• pp.775-781
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• 2011

For the measurement of absolute position of mobile robot in indoor environments, the ultrasonic positioning systems using ultrasound have been researched for several years. Most of these ultrasonic positioning systems to avoid interference between the ultrasound are used for sequential transmitting. However, due to the use of sequential transmitting, the positions of transmitter to receive an ultrasound will change when the mobile robot moves. Therefore the accuracy of positioning is reduced. In this paper, the new position estimation algorithm with weighting factor according to the time of receipt is proposed. By applying the proposed algorithm to existing Ultrasonic Satellite System(USAT), the improved USAT is configured. The positioning performance of the improved USAT with the proposed position estimation algorithm are verified by experiments.

• Journal of Institute of Control, Robotics and Systems
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• v.21 no.12
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• pp.1185-1192
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• 2015

In this paper, a study of advanced sound source localization is conducted by eliminating the noise of the sound source using the discrete wavelet transform. And experiments are conducted to evaluate the performance of the proposed system that the mobile robot follows sound source stably. In addition, we compare the position estimation performance by applying a discrete wavelet transform to improve the reliability of the sound signal. The experimental results reveal that the de-nosing filter which removes the noise component in sound source can make the performance of position estimation more precisely and help the mobile robot distinguish the objective sound source clearly.

• Proceedings of the KIEE Conference
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• 1988.11a
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• pp.310-313
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• 1988

It is an important thing to detect the Pole position for vector control of permanent magnet synchronous motor. In this paper, traditional position sensor is removed with the estimation of the pole position by using adaptive identification. Also, the proposed algorithm is simulated and the results are very good performance.

• Journal of Power Electronics
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• v.14 no.6
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• pp.1243-1253
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• 2014

The phase inductance of a switch reluctance motor (SRM) is significantly nonlinear. With different saturation conditions, the phase inductance shape is clearly changed. This study focuses on the relationship between coefficient and current in an inductance model with ignored harmonics above the order of 3. A position estimation method based on the variable coefficient inductance model is proposed in this paper. A four-quadrant sensorless control system of the SRM drive is constructed based on the relationship between variable coefficient inductance and rotor position. The proposed algorithms are implemented in an experimental SRM test setup. Experimental results show that the proposed method estimates position accurately in operating two/four-quadrants. The entire system also has good static and dynamic performance.