• Title/Summary/Keyword: Tracking Error

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MPPT Control of Photovoltaic using Variable IC Method (가변 IC 방법을 이용한 태양광 발전의 MPPT 제어)

  • Ko, Jae-Sub;Chung, Dong-Hwa
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.26 no.8
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    • pp.27-34
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    • 2012
  • This paper proposes variable incremental conductance(IC) algorithm for maximum power point tracking(MPPT) control of photovoltaic. The conventional perturbation & observation(PO) and IC MPPT control algorithm generally uses fixed step size. A small step size reduces a tracking error in the steady state but slows a tracking speed in the transient state. Also, a large step size is fast a tracking speed but increases a tracking error. Therefore, this paper proposes variable IC MPPT algorithm that adjust automatically step size according to operating conditions. To improve a tracking speed and accuracy, when operating point is far from the maximum power point(MPP), the step size uses maximum value and when a operating point is near from the MPP, the step size uses variable step size that adjust according to slope of P-V curve. The validity of MPPT algorithm proposed in this paper prove through compare with conventional PO and IC MPPT algorithm.

Regularized Zero-Forcing Beam Design under Time-Varying Channels

  • Yu, Heejung;Kim, Taejoon
    • ETRI Journal
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    • v.38 no.3
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    • pp.435-443
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    • 2016
  • In this paper, an efficient beam tracking algorithm for a regularized zero-forcing (RZF) approach in slowly fading multiple-input and single-output (MISO) broadcast channels is considered. By modifying an RZF equation, an RZF beam tracking algorithm is proposed using matrix perturbation theory. The proposed algorithm utilizes both beams from the previous time step and channel difference (between the previous and current time steps) to calculate the RZF beams. The tracking performance of the proposed algorithm is analyzed in terms of the mean square error (MSE) between a tracking approach and an exact recomputing approach, and in terms of the additional MSE caused by the beam tracking error at the receiver. Numerical results show that the proposed algorithm has almost the same performance as the exact recomputing approach in terms of the sum rate.

Performance of PN Code Tracking Loop for a DS/CDMA System with Imperfect Power Control and Shadowing

  • Kim, Jin-Young
    • Proceedings of the IEEK Conference
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    • 2000.07a
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    • pp.501-504
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    • 2000
  • In this paper, performance of a pseudonoise (PN) code tracking loop is analyzed and simulated for a direct-sequence/code-division multiple access ( DS/CDMA) system with imperfect power control in a multipath fading channel. A noncoherent first-order delay-locked loop (DLL) is considered as a PN code tracking loop. Power control error is modeled as a log-normally distributed random variable. From the simulation results, it is shown that for smaller discriminator offset, tracking jitter performance is improved while MTLL performance is degraded. It is shown that large power control error and heavy shadowing substantially degrade the PN tracking performance. The analysis in this paper can be applicable to design of PN code tracking loop for a DS/CDMA system.

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Walking Pattern Analysis for Reducing Trajectory Tracking Error in a Biped Robot (이족보행로봇의 궤적 추종 오차 감소를 위한 걸음새 분석)

  • 노경곤;공정식;김진걸
    • Journal of Institute of Control, Robotics and Systems
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    • v.8 no.10
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    • pp.890-897
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    • 2002
  • This paper deals with the reduction of trajectory tracking error by changing the initial postures of a biped robot. Gait of a biped robot depends on the constraints of mechanical kinematics and the initial states including the posture. Also the dynamic walking stability in a biped robot system is analyzed by zero moment point(ZMP) among the stabilization indices. Path trajectory, in which knee joint is bent forward like human's cases, is applied to most cases considered with above conditions. A new initial posture, which is similar to bird's gait, is proposed to decrease trajectory tracking error and it is verified through real experimental results.

Two axis control characteristics of linear motor feed system (리니어모터 이송시스템의 2축제어특성에 관한 연구)

  • 유송민;신관수
    • Proceedings of the Korean Society of Machine Tool Engineers Conference
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    • 2002.10a
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    • pp.405-410
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    • 2002
  • Linear motor food system control algorithm was extended to the two axis system. Among several factors considered, overshoot of the response was the most important one in minimizing position tracking error. Balance between overshoot and settling time has to be adjusted to guarantee to best tracking performance. Tracking route was carefully executed to eliminate the possible error during the machining process. Even though there exists slight discrepancy between desired mute and cutting track at the corner, precision machining could be implemented using the cutting scheme introduced.

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Relationship Between GPS Code and Carrier Tracking Performance for GPS Receivers (GPS 수신기에서 코드 추적 성능와 반송파 추적 성능의 관계)

  • 임영재;박찬식
    • 제어로봇시스템학회:학술대회논문집
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    • 2000.10a
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    • pp.56-56
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    • 2000
  • In this paper, the relationship between GPS code and carrier tracking performance is given. Through the error analysis and experiments, the performance of code tracking loop can be improved using narrow correlation. The performance of code tracking loop can be also improved if the better carrier tracking loop is used. On the other hand, the performance of carrier tracking loop is independent of that of code tracking loop.

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Analysis of Tracking Accuracy with Consideration of Fighter Radar Measurement Characteristics (전투기 레이다 측정 특성을 고려한 추적정확도 분석)

  • Seo, Jeongjik
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.29 no.8
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    • pp.640-647
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    • 2018
  • This study analyzes the tracking accuracy(tracking errors) of fighter radar. Measurement error, detection failure, and radar cross section(RCS) fluctuation in radar measurements degrade the measurement quality and hence affect the tracking accuracy. Therefore, these radar measurement characteristics need to be considered when analyzing the tracking accuracy. In this paper, a method for analyzing the tracking accuracy is proposed; this method considers the detection error, detection probability, and RCS fluctuation. Results from experiments conducted with the proposed method show that the detection probability and RCS fluctuation affect tracking accuracy.

Performance Analysis of Tactical Ballistic Missile Tracking Filters in Phased Array Multi-Function Radar (위상 배열 다기능 레이더의 탄도탄 추적 필터 성능 분석)

  • Jung, Kwang-Yong
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.23 no.8
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    • pp.995-1001
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    • 2012
  • This paper compares the performance of several tracking filters, namely, alpha-beta filter, Kalman filter and TBM tracking filter for ballistic target tracking problem using multi-function radar. Every of three tracking filters suggested was tested on simulator developed in accordance with TBM trajectory and MFR RSP measurement. The result shows the method using TBM tracking filter gives 75.3 % decreased velocity RMS error than alpha-beta filter. After initialization, the RMS error of range and velocity of the proposed filter is also smaller than the Kalman filter. Finally the proposed filter is suitable for high-speed TBM tracking due to the stable angle tracking accuracy.

Receiver Design for Satellite Navigation Signals using the Tiered Differential Polyphase Code

  • Jo, Gwang Hee;Noh, Jae Hee;Lim, Deok Won;Son, Seok Bo;Hwang, Dong-Hwan;Lee, Sang Jeong
    • Journal of Positioning, Navigation, and Timing
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    • v.10 no.4
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    • pp.307-313
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    • 2021
  • Modernized GNSS signal structures tend to use tiered codes, and all GNSSs use binary codes as secondary codes. However, recently, signals using polyphase codes such as Zadoff-Chu sequence have been proposed, and are expected to be utilized in GNSS. For example, there is Tiered Differential Polyphase Code (TDPC) using polyphase code as secondary code. In TDPC, the phase of secondary code changes every one period of the primary code and a time-variant error is added to the carrier tracking error, so carrier tracking ambiguity exists until the secondary code phase is found. Since the carrier tracking ambiguity cannot be solved using the general GNSS receiver architecture, a new receiver architecture is required. Therefore, in this paper, we describe the carrier tracking ambiguity and its cause in signal tracking, and propose a receiver structure that can solve it. In order to prove the proposed receiver structure, we provide three signal tracking results. The first is the differential decoding result (secondary code sync) using the general GNSS receiver structure and the proposed receiver structure. The second is the IQ diagram before and after multiplying the secondary code demodulation when carrier tracking ambiguity is solved using the proposed receiver structure. The third is the carrier tracking result of the legacy GPS (L1 C/A) signal and the signal using TDPC.

Useful evaluation of 3D target location correction by using Xsight spine tracking system in CyberKnife (사이버나이프에서 Xsight spine tracking system을 이용한 3D 표적위치보정의 유용성 평가)

  • Jeong, Young-Joon;Kim, Sang-Hyun
    • Journal of Digital Convergence
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    • v.13 no.1
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    • pp.331-339
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    • 2015
  • The purpose of this study is to evaluate utility of rotating adjustment using Xsight spine tracking system in 3D DOF location adjusting method, to minimize error between 6D DOF and 3D DOF in fiducial tracking system. In this study, the result of 6D DOF target location error is $0.124{\pm}0.058mm$, using fiducial inside tumor 3D DOF $0.673{\pm}0.142mm$, outside tumor $1.126{\pm}0.253mm$, apply with Xsight spine tracking system 3D DOF $0.542{\pm}0.103mm$. As the experiment shows, it was demonstrated that rotating adjustment through Xsight spine tracking system is valuable in case of treatment in 3D DOF location error that makes increasing accuracy and dose distribution each approximately 48% and 3%. In accordance with result of this study is useful rotation.