• Title/Summary/Keyword: Real-time parameter estimation

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Fault Detection and Identification of Uninhabited Aerial Vehicle using Similarity Measure (유사측도를 이용한 무인기의 고장진단 및 검출)

  • Park, Wook-Je;Lee, Sang-Hyuk
    • Journal of the Korean Society for Aviation and Aeronautics
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    • v.19 no.2
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    • pp.16-22
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    • 2011
  • It is recognized that the control surface fault is detected by monitoring the value of the coefficients due to the control surface deviation. It is found out the control surface stuck position by comparing the trim value with the reference value. To detect and isolate the fault, two mixed methods apply to the real-time parameter estimation and similarity measure. If the scatter of aerodynamic coefficients for the fault and normal are closing nearly, fault decision is difficult. Applying similarity measure to decide for fault or not, it makes a clear and easy distinction between fault and normal. Low power processor is applied to the real-time parameter estimator and computation of similarity measure.

Prediction of Ozone Formation Based on Neural Network and Stochastic Method (인공신경망 및 통계적 방법을 이용한 오존 형성의 예측)

  • Oh, Sea Cheon;Yeo, Yeong-Koo
    • Clean Technology
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    • v.7 no.2
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    • pp.119-126
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    • 2001
  • The prediction of ozone formation was studied using the neural network and the stochastic method. Parameter estimation method and artificial neural network(ANN) method were employed in the stochastic scheme. In the parameter estimation method, extended least squares(ELS) method and recursive maximum likelihood(RML) were used to achieve the real time parameter estimation. Autoregressive moving average model with external input(ARMAX) was used as the ozone formation model for the parameter estimation method. ANN with 3 layers was also tested to predict the ozone formation. To demonstrate the performance of the ozone formation prediction schemes used in this work, the prediction results of ozone formation were compared with the real data. From the comparison it was found that the prediction schemes based on the parameter estimation method and ANN method show an acceptable accuracy with limited prediction horizon.

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An algorithm for real time blood flow estimation of LDF (LDF의 실시간 혈류추정을 위한 알고리즘)

  • Kim, Jong-Weon;Ko, Han-Woo
    • Proceedings of the KOSOMBE Conference
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    • v.1998 no.11
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    • pp.78-79
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    • 1998
  • This paper describes a real time algorithm for blood flow estimation of LDF(laser Doppler flowmeter). Many algorithms for blood flow estimation are using power spectral density of Doppler signal by blood flow. In these research, the fast Fourier transformation is used to estimate power spectral density. This is a block processing procedure rather than real time processing. The algorithm in this paper used parametric spectral estimation. This has real time capability by estimation of AR(autoregressive) parameters sample by sample, and has smoothing power spectrum. Also, the frequency resolution is not limited by number of samples used to estimate AR parameter. Another advantage of this algorithm is that AR model enhance SNR.

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SPMSM Mechanical Parameter Estimation Using Sliding-Mode Observer and Adaptive Filter (슬라이딩 모드 관측기와 적응 필터를 이용한 SPMSM 기계 파라미터 추정)

  • Kim, Hyoung-Woo;Choi, Joon-Young
    • The Transactions of the Korean Institute of Power Electronics
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    • v.24 no.1
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    • pp.33-39
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    • 2019
  • We propose a mechanical parameter estimation algorithm for surface-mounted permanent magnet synchronous motors (SPMSMs) using a sliding-mode observer (SMO) and an adaptive filter. The SMO estimates system disturbances in real time, which contain the information on mechanical parameters. A desirable feature that distinguishes the proposed estimation algorithm from other existing mechanical parameter estimators is that the adaptive filter estimates electromagnetic torque to improve the estimation performance. Moreover, the SMO acts as a low-pass filter to suppress the chattering effect, which enables the smooth output signals of the SMO. We verify the mechanical parameter estimation performance for SPMSM by conducting extensive experiments for the proposed algorithm.

Real-Time Identification and Estimation of Transformer Tap Ratios Containing Errors

  • Kim, Hongrae;Kwon, Hyung-Seok
    • KIEE International Transactions on Power Engineering
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    • v.2A no.3
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    • pp.109-113
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    • 2002
  • This paper addresses the issue of parameter error identification and estimation in electric power systems. Parameter error identification and estimation is carried out as a part of the state estimation. A two stage estimation procedure is used to detect and identify parameter errors. Suspected parameters are identified by the WLAV state estimator in the first stage. A new WLAV state estimator adding suspected system parameters in the state vector is used to estimate the exact values of parameters. Supporting examples are given by using the IEEE 14 bus system.

Real-time Robotic Vision Control Scheme Using Optimal Weighting Matrix for Slender Bar Placement Task (얇은 막대 배치작업을 위한 최적의 가중치 행렬을 사용한 실시간 로봇 비젼 제어기법)

  • Jang, Min Woo;Kim, Jae Myung;Jang, Wan Shik
    • Journal of the Korean Society of Manufacturing Technology Engineers
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    • v.26 no.1
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    • pp.50-58
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    • 2017
  • This paper proposes a real-time robotic vision control scheme using the weighting matrix to efficiently process the vision data obtained during robotic movement to a target. This scheme is based on the vision system model that can actively control the camera parameter and robotic position change over previous studies. The vision control algorithm involves parameter estimation, joint angle estimation, and weighting matrix models. To demonstrate the effectiveness of the proposed control scheme, this study is divided into two parts: not applying the weighting matrix and applying the weighting matrix to the vision data obtained while the camera is moving towards the target. Finally, the position accuracy of the two cases is compared by performing the slender bar placement task experimentally.

A Study on the Vehicle Dynamics and Road Slope Estimation (차량동특성 및 도로경사도 추정에 관한 연구)

  • Kim, Moon-Sik
    • Journal of the Korean Society of Industry Convergence
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    • v.22 no.5
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    • pp.575-582
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    • 2019
  • Advanced driving assist system can support safety of driver and passengers which may require vehicle dynamics states as well as road geometry. It is essential to have in real-time estimation of related variables and parameters. Among the road geometry parameters, road slope angle which can not be measured is essential parameter in pose estimation, adaptive cruise control and others on sag road. In this paper, Kalman filter based method for the estimation of the vehicle dynamics and road slope angle using a nonlinear vehicle model is proposed. It uses a combination of Kalman filter as Cascade Extended Kalman Filter. CEKF uses measured vehicle states such as yaw rate, longitudinal/lateral acceleration and velocity. Unknown vehicle parameters such as center of gravity and inertia are obtained by 2 D.O.F lateral model and experimentally. Simulation and Experimental tests conducted with commercialized vehicle dynamics model and real-car.

The Parameter Estimation of Linear System via Walsh(Cal, Sal) Functions (WALSH(CAL, SAL) 함수(函數)를 이용(利用)한 선형계(線形系)의 파라미터 추정(推定)에 관(關)한 연구(硏究))

  • Chae, Young-Moo;Park, Jun-Hoon;Kim, Jong-Boo;Kim, Min-Hyung
    • Proceedings of the KIEE Conference
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    • 1991.07a
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    • pp.695-698
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    • 1991
  • In this paper tried the estimation of parameter using of Cal-Sal functions. System equation given by the linear differential equation is converted into the integral equation, operation matrix for integral of Cal-Sal functions is used to find the estimation of parameter on the given system. Converting linear differential equation to linear algebraic equation, the method presented here computing time and required memory size can be reduced. Therefore real time data process can be possible.

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Maximum penalized likelihood estimation for a stress-strength reliability model using complete and incomplete data

  • Hassan, Marwa Khalil
    • Communications for Statistical Applications and Methods
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    • v.25 no.4
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    • pp.355-371
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    • 2018
  • The two parameter negative exponential distribution has many practical applications in queuing theory such as the service times of agents in system, the time it takes before your next telephone call, the time until a radioactive practical decays, the distance between mutations on a DNA strand, and the extreme values of annual snowfall or rainfall; consequently, has many applications in reliability systems. This paper considers an estimation problem of stress-strength model with two parameter negative parameter exponential distribution. We introduce a maximum penalized likelihood method, Bayes estimator using Lindley approximation to estimate stress-strength model and compare the proposed estimators with regular maximum likelihood estimator for complete data. We also introduce a maximum penalized likelihood method, Bayes estimator using a Markov chain Mote Carlo technique for incomplete data. A Monte Carlo simulation study is performed to compare stress-strength model estimates. Real data is used as a practical application of the proposed model.

A Novel Sensorless Low Speed Vector Control for Synchronous Reluctance Motors Using a Block Pulse Function-Based Parameter Identification

  • Ahmad Ghaderi;Tsuyoshi Hanamoto;Teruo Tsuji
    • Journal of Power Electronics
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    • v.6 no.3
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    • pp.235-244
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    • 2006
  • Recently, speed sensorless vector control for synchronous reluctance motors (SYRMs) has deserved attention because of its advantages. Although rotor angle calculation using flux estimation is a straightforward approach, the DC offset can cause an increasing pure integrator error in this estimator. In addition, this method is affected by parameter fluctuation. In this paper, to control the motor at the low speed region, a modified programmable cascaded low pass filter (MPCPLF) with sensorless online parameter identification based on a block pulse function is proposed. The use of the MPCLPF is suggested because in programmable, cascade low pass filters (PCLPF), which previously have been applied to induction motors, the drift increases vastly wl)en motor speed decreases. Parameter identification is also used because it does not depend on estimation accuracy and can solve parameter fluctuation effects. Thus, sensorless speed control in the low speed region is possible. The experimental system includes a PC-based control with real time Linux and an ALTERA Complex Programmable Logic Device (CPLD), to acquire data from sensors and to send commands to the system. The experimental results show the proposed method performs well, speed and angle estimation are correct. Also, parameter identification and sensorless vector control are achieved at low speed, as well as, as at high speed.