• Title/Summary/Keyword: parameter projection method

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Online Parameter Estimation of SPMSM using Affine Projection Algorithm (Affine Projection 알고리즘을 이용한 표면 부착형 영구자석 전동기의 온라인 파라미터 추정)

  • Moon, Byung-Hun;Kim, Hyoung-Woo;Choi, Joon-Young
    • The Transactions of the Korean Institute of Power Electronics
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    • v.23 no.1
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    • pp.66-71
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    • 2018
  • We propose an online parameter estimation method for surface-mounted permanent-magnet synchronous motor (SPMSM) using an affine projection algorithm (APA). The proposed method estimates parameters with two APAs based on the discrete-time model equation of SPMSM during motor operation. The first APA is designed to estimate inductance, and the second APA is designed to estimate resistance and flux linkage. However, in case when the d-axis current is controlled to 0A, the second APA cannot estimate resistance and flux linkage simultaneously because the matrix rank in APA becomes deficient. To overcome this problem, we temporarily inject a negative reference current input to the d-axis control loop, and the matrix in the APA then becomes full rank, which enables the simultaneous estimation of resistance and flux linkage. The proposed method is verified by PSIM simulation and an actual experiment, and the results reveal that SPMSM parameters can be estimated online during motor operation.

Method and Apparatus for Digital Auto Convergence of Projection Video Display

  • Tai, Wen-Chih;Mo, Chi-Neng;Juan, Chang-Jung;Tsai, Ming-Jong
    • 한국정보디스플레이학회:학술대회논문집
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    • 2005.07b
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    • pp.1171-1174
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    • 2005
  • This thesis provides a new digital convergence method and apparatus which uses area photo sensor and new analog to digital algorithmic to identify the correct digital pattern position factor of the projection system. This method and apparatus can be applied to the convergence correction in a TV receiver with a display that comprises a display screen with photo sensors positioned adjacent to screen edges. It also can be applied to the manufacture process detection of the projection system to adjust the associative convergence parameter. In this paper, demonstrate how this convergence detecting algorithmic was implemented with four area photo sensors of special designed pattern to the rear projection CRT TV.

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Adaptive Fuzzy Sliding Mode Control for Nonlinear Systems without Parameter Projection Method (파라미터 투영 기법이 필요 없는 비선형 시스템의 적응 퍼지 슬라이딩 모드 제어)

  • Seo, Sam-Jun
    • Journal of the Korean Institute of Intelligent Systems
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    • v.21 no.4
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    • pp.499-505
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    • 2011
  • In this paper, we proposed an adaptive fuzzy sliding mode control for nonlinear systems without parameter projection method. By modifying the controller structure, the parameters of the estimated input gain function are guaranteed not being identically zero and it is shown that the control scheme will not cause any implementation problem even if the estimated value of input gain function is zero at any moment during on-line operations. Except for the input gain function which an approximate estimate for its lower bound is needed, the proposed control scheme does not assume a priori the exact values of the bounding parameters. Based on Lyapunov synthesis methods, the overall control system guarantees that the tracking error asymptotically converges to zero and that all signals involved in controller are uniformly bounded. This can be illustrated by the simulation results for an inverted pendulum system.

Correction of the Refraction Effect on the Real-Time Nonlinear Parameter Tomogram (초음파 비선형 단층영상에 나타나는 굴절의 영향 보정법)

  • 이현주;이강호;최종호;최종수
    • Journal of the Korean Institute of Telematics and Electronics B
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    • v.28B no.5
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    • pp.335-342
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    • 1991
  • A real-tme nonlinear parameter tomography is pumping wave method. This tomorgraphy has a merit which requires no 180$^{\circ}$ projection datum, while the ray-bending effect is remrkably remained on the reconstructed image. In this paper we intend to compensate this ray-bending effect using the perturbation method. Impulsive pumping wave makes derived compensative term simple form, nad the compensative image is easily obtained. We perform computer simulation to confirm the improvement of corrected imate.

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A Quasi-Likelihood Approach to Nonlinear Filtering Problems

  • Kim, Yoon-Tae
    • Journal of the Korean Statistical Society
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    • v.27 no.2
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    • pp.221-235
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    • 1998
  • Suppose that an observed process can be written as the additive model of the signal process and the noise process with unknown parameters. In practice the signal process is not directly observed. We consider the problem of estimating parameter from the observation process using the quasi-likelihood method.

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SUPERCONVERGENCE OF HYBRIDIZABLE DISCONTINUOUS GALERKIN METHOD FOR SECOND-ORDER ELLIPTIC EQUATIONS

  • MOON, MINAM;LIM, YANG HWAN
    • Journal of the Korean Society for Industrial and Applied Mathematics
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    • v.20 no.4
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    • pp.295-308
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    • 2016
  • We propose a projection-based analysis of a new hybridizable discontinuous Gale-rkin method for second order elliptic equations. The method is more advantageous than the standard HDG method in a sense that the new method has higher-order accuracy and lower computational cost, and is more flexible. Notable distinctions of our new method, when compared to the standard HDG emthod, are that our method uses $L^2$-projection and suitable stabilization parameter depending on a mesh size for superconvergence. We show that the error for the solution of the equation converges with order p + 2 when we only use polynomials of degree p + 1 as a finite element space without postprocessing. After establishing the theory, we carry out numerical tests to demonstrate and ensure that the proposed method is effective and accurate in practice.

ITERATIVE FACTORIZATION APPROACH TO PROJECTIVE RECONSTRUCTION FROM UNCALIBRATED IMAGES WITH OCCLUSIONS

  • Shibusawa, Eijiro;Mitsuhashi, Wataru
    • Proceedings of the Korean Society of Broadcast Engineers Conference
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    • 2009.01a
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    • pp.737-741
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    • 2009
  • This paper addresses the factorization method to estimate the projective structure of a scene from feature (points) correspondences over images with occlusions. We propose both a column and a row space approaches to estimate the depth parameter using the subspace constraints. The projective depth parameters are estimated by maximizing projection onto the subspace based either on the Joint Projection matrix (JPM) or on the the Joint Structure matrix (JSM). We perform the maximization over significant observation and employ Tardif's Camera Basis Constraints (CBC) method for the matrix factorization, thus the missing data problem can be overcome. The depth estimation and the matrix factorization alternate until convergence is reached. Result of Experiments on both real and synthetic image sequences has confirmed the effectiveness of our proposed method.

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Crack growth life model for fatigue susceptible structural components in aging aircraft

  • Chou, Karen C.;Cox, Glenn C.;Lockwood, Allison M.
    • Structural Engineering and Mechanics
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    • v.17 no.1
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    • pp.29-50
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    • 2004
  • A total life model was developed to assess the service life of aging aircraft. The primary focus of this paper is the development of crack growth life projection using the response surface method. Crack growth life projection is a necessary component of the total life model. The study showed that the number of load cycles N needed for a crack to propagate to a specified size can be linearly related to the geometric parameter, material, and stress level of the component considered when all the variables are transformed to logarithmic values. By the Central Limit theorem, the ln N was approximated by Gaussian distribution. This Gaussian model compared well with the histograms of the number of load cycles generated from simulated crack growth curves. The outcome of this study will aid engineers in designing their crack growth experiments to develop the stochastic crack growth models for service life assessments.

Leader-following Approach Based Adaptive Formation Control for Mobile Robots with Unknown Parameters (미지의 파라미터를 갖는 이동 로봇들을 위한 선도-추종 방법 기반 적응 군집 제어)

  • Moon, Ssurey;Park, Bong-Seok;Choi, Yoon-Ho;Park, Jin-Bae
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.60 no.8
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    • pp.1592-1598
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    • 2011
  • In this paper, a formation control method based on the leader-following approach for nonholonomic mobile robots is proposed. In the previous works, it is assumed that the followers know the leader's velocity by means of communication. However, it is difficult that the followers correctly know the leader's velocity due to the contamination or delay of information. Thus, in this paper, an adaptive approach based on the parameter projection algorithm is proposed to estimate the leader's velocity. Moreover, the adaptive backstepping technique is used to compensate the effects of a dynamic model with the unknown time-invariant and time-varying parameters. From the Lyapunov stability theory, it is proved that the errors of the closed-loop system are uniformly ultimately bounded. Simulation results illustrate the effectiveness of the proposed control method.

3D Reconstruction using three vanishing points from a single image

  • Yoon, Yong-In;Im, Jang-Hwan;Kim, Dae-Hyun;Park, Jong-Soo
    • Proceedings of the IEEK Conference
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    • 2002.07b
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    • pp.1145-1148
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    • 2002
  • This paper presents a new method which is calculated to use only three vanishing points in order to compute the dimensions of object and its pose from a single image of perspective projection taken by a camera and the problem of recovering 3D models from three vanishing points of box scene. Our approach is to compute only three vanishing points without this information such as the focal length, rotation matrix, and translation from images in the case of perspective projection. We assume that the object can be modeled as a linear function of a dimension vector ν. The input of reconstruction is a set of correspondences between features in the model and features in the image. To minimize each the dimensions of the parameterized models, this reconstruction of optimization can be solved by the standard nonlinear optimization techniques with a multi-start method which generates multiple starting points for the optimizer by sampling the parameter space uniformly.

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