• Title/Summary/Keyword: Surface tracking

Search Result 532, Processing Time 0.039 seconds

The Characteristics of Tracking Phenomena and Surface Discharge Using Various Types of Electrode Arrangement in LN2 at the Atmospheric Pressure (대기압하의 액체질소중 전극배치에 따른 고체유전체 표면의 연면방전 및 Tracking현상)

  • 박광서;신호영;최병주;박원주;이광식
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
    • /
    • v.17 no.3
    • /
    • pp.49-55
    • /
    • 2003
  • This paper studied characteristics of surface discharge and tracking phenomena on the surface of solid insulators in Liquid Nitrogen(LN2) noticed as a cooling medium of high temperature superconductor. In order to investigate the bubble effect which have much influence on electric surface discharge in Liquid Nitrogen, knife type electrode and plane electrode were formed oppositely with A-mode, B-mode and C-mode configuration. It is considered that these result are fundamental data for electric insulation design of superconductor and cryogenic application machinery which will be studied and developed in the future.

Double Sliding Surfaces based on a Sliding Mode Control for a Tracking Control of Mobile Robots (이동 로봇의 추종 제어를 위한 이중 슬라이딩 표면에 기반한 슬라이딩 모드 제어)

  • Lee, Jun Ku;Choi, Yoon Ho;Park, Jin Bae
    • Journal of Institute of Control, Robotics and Systems
    • /
    • v.19 no.6
    • /
    • pp.495-500
    • /
    • 2013
  • This paper proposes a double sliding surfaces based on a sliding mode control for a tracking control of nonholonomic mobile robots in the Cartesian coordinates. In order to remove sliding surface constraints, we design the additional sliding surface for the heading angle with respect to the newly defined coordinates. Then, we define the switching law based on the posture error to combine the designed sliding surface with the previous one. By using the double sliding surfaces and the switching law, we obtain the control law for arbitrary trajectories. It is proved that the position tracking error and the heading direction error asymptotically converge to zero, respectively, with the Lyapunov stability theory. Finally, through computer simulations, we demonstrate the effectiveness of the proposed control system.

Visual Object Tracking using Surface Fitting for Scale and Rotation Estimation

  • Wang, Yuhao;Ma, Jun
    • KSII Transactions on Internet and Information Systems (TIIS)
    • /
    • v.15 no.5
    • /
    • pp.1744-1760
    • /
    • 2021
  • Since correlation filter appeared in the field of object tracking, it plays an increasingly vital role due to its excellent performance. Although many sophisticated trackers have been successfully applied to track the object accurately, very few of them attaches importance to the scale and rotation estimation. In order to address the above limitation, we propose a novel method combined with Fourier-Mellin transform and confidence evaluation strategy for robust object tracking. In the first place, we construct a correlation filter to locate the target object precisely. Then, a log-polar technique is used in the Fourier-Mellin transform to cope with the rotation and scale changes. In order to achieve subpixel accuracy, we come up with an efficient surface fitting mechanism to obtain the optimal calculation result. In addition, we introduce a confidence evaluation strategy modeled on the output response, which can decrease the impact of image noise and perform as a criterion to evaluate the target model stability. Experimental experiments on OTB100 demonstrate that the proposed algorithm achieves superior capability in success plots and precision plots of OPE, which is 10.8% points and 8.6% points than those of KCF. Besides, our method performs favorably against the others in terms of SRE and TRE validation schemes, which shows the superiority of our proposed algorithm in scale and rotation evaluation.

Tracking Propagation Mechanism on the Surface of Polyvinyl-Chloride-Sheathed Flat Cord based on Electric Field Analysis and Gas Discharge Physics (전계해석과 기체방전 이론을 기반으로 한 Polyvinyl-Chloride-Sheathed Flat Cord 표면의 트래킹 진전 메커니즘)

  • Lim, Dong-Young;Park, Herie;Jee, Seung-Wook
    • Fire Science and Engineering
    • /
    • v.33 no.2
    • /
    • pp.30-38
    • /
    • 2019
  • Tracking, which is one of the main causes of electrical fires, is perceived as a physical phenomenon of electrical discharge. Hence tracking should be explained based on electric field analysis, conduction path by electron generation, and gas discharge physics. However, few papers have considered these details. This paper proposes a tracking mechanism including their effects on tracking progress. In order to prove this mechanism, a tracking experiment, an electric field analysis for the carbonization evolution model, and an explanation of the tracking process by gas discharge physics were conducted. From the tracking experiment, the current waveforms were measured at each stage of the tracking progress from corona discharge to tracking breakdown. The electric field analysis was carried out in order to determine the electric field on the surface of a dry-band and the high electric field region for electron generation during the generation and progress of carbonization. In this paper, the proposed tracking mechanism consisted of six stages including electron avalanche by corona discharge, accumulation of positive ions, expansion of electron avalanche, secondary electron emission avalanche, streamer, and tracking by conductive path. The pulse current waveforms measured in the tracking experiment can be explained by the proposed tracking mechanism. The results of this study will be used as the technical data to detect tracking phenomenon, which is the cause of electric fire, and to improve the proof tracking index.

An Improved Tracking Servo System in Optical Disk Drives (광디스크 드라이브의 개선된 트래킹 서보 시스템)

  • Lee, Tae-Gyu;Jeong, Dong-Seul;Chung, Chung-Choo
    • Journal of the Institute of Electronics Engineers of Korea SC
    • /
    • v.44 no.4 s.316
    • /
    • pp.67-73
    • /
    • 2007
  • An optical pick up generally has coupled dynamics between focusing and tracking servos. The coupled dynamics reduces tracking performance of optical disk drives. A conventional control method is holding the previous tracking control command in the presence of surface defect. The method has a long settling time. If the defective area is getting larger, objective lens will get away from the following track. In order to overcome this problem, this paper proposed a new control method for optical disk drives based on a prediction of tracking error and focusing error. We present how to compensate the coupled dynamics so that reduced setting time is achieved. It is verified by experiments that the proposed method brings an improved performance in the presence of surface defect as well as in the normal operating condition.

A New VOF-based Numerical Scheme for the Simulation of Fluid Flow with Free Surface(I)-New Free Surface Tracking Algorithm and Its Verification- (자유 표면이 존재하는 유체 유동 해석을 위한 VOF방법의 기반의 새로운 수치 기법(I)-새로운 자유 표면 추적 알고리즘 및 검증-)

  • Kim, Min-Su;Sin, Su-Ho;Lee, U-Il
    • Transactions of the Korean Society of Mechanical Engineers B
    • /
    • v.24 no.12
    • /
    • pp.1555-1569
    • /
    • 2000
  • Numerical simulation of fluid flow with moving free surface has been carried out. For the free surface flow, a VOF(Volume of Fluid)-based algorithm utilizing a fixed grid system has been investigated. In order to reduce numerical smearing at the free surface represented on a fixed grid system, a new free surface tracking algorithm based on the donor-acceptor scheme has been presented. Novel features of the proposed algorithm are characterized as two numerical tools; the orientation vector to represent the free surface orientation in each cell and the baby-cell to determine the fluid volume flux at each cell boundary. The proposed algorithm can be easily implemented in any irregular non-uniform grid systems that are usual in finite element method (FEM). Moreover, the proposed algorithm can be extended and applied to the 3-D free surface flow problem without additional efforts. For computation of unsteady incompressible flow, a finite element approximation based on the explicit fractional step method has been adopted. In addition, the SUPG(streamline upwind/Petrov-Galerkin) method has been implemented to deal with convection dominated flows. Combination of the proposed free surface tracking scheme and explicit fractional step formulation resulted in an efficient solution algorithm. Validity of the present solution algorithm was demonstrated from its application to the broken dam and the solitary wave propagation problems.

Trajectory tracking control of underactuated USV based on modified backstepping approach

  • Dong, Zaopeng;Wan, Lei;Li, Yueming;Liu, Tao;Zhang, Guocheng
    • International Journal of Naval Architecture and Ocean Engineering
    • /
    • v.7 no.5
    • /
    • pp.817-832
    • /
    • 2015
  • This paper presents a state feedback based backstepping control algorithm to address the trajectory tracking problem of an underactuated Unmanned Surface Vessel (USV) in the horizontal plane. A nonlinear three Degree of Freedom (DOF) underactuated dynamic model for USV is considered, and trajectory tracking controller that can track both curve trajectory and straight line trajectory with high accuracy is designed as the well known Persistent Exciting (PE) conditions of yaw velocity is completely relaxed in our study. The proposed controller has further been enriched by incorporating an integral action additionally for enhancing the steady state performance and control precision of the USV trajectory tracking control system. Global stability of the overall system is proved by Lyapunov theory and Barbalat's Lemma, and then simulation experiments are carried out to demonstrate the effectiveness of the controller designed.

A New Improved Continuous Variable Structure Tracking Controller For BLDD Servo Motors (브러쉬없는 직접구동 전동기를 위한 새로운 개선된 연속 가변구조 추적제어기)

  • Lee, Jung-Hoon
    • Journal of IKEEE
    • /
    • v.9 no.1 s.16
    • /
    • pp.47-56
    • /
    • 2005
  • A new improved robust variable structure tracking controller is presented to provide an accurately prescribed tracking performance for brushless direct drive(BLDD) servo motors(SM) under uncertainties and load variations. A special integral sliding surface suggested for removing the reaching phase problems can define its ideal sliding mode and virtual ideal sliding trajectory from an initial position of SM. The tracking error caused by the nonzero value of the sliding surface is derived. A corresponding continuous control input with the disturbance observer is suggested to track a predetermined virtual ideal sliding trajectory within a prescribed value under all the uncertainties and load variations. The usefulness of the proposed algorithm is demonstrated through the comparative simulations for a BLDD SM under load variations.

  • PDF

Simulation Study on the Multipath Tracking Errors (다중경로 추적오차 모사 알고리즘 연구)

  • Kim, Min-Nyun;Lim, Joong-Soo;Chae, Gyoo-Soo;Ye, Sung-Hyuck;Ryu, Chung-Ho
    • Journal of the Korea Academia-Industrial cooperation Society
    • /
    • v.10 no.9
    • /
    • pp.2274-2279
    • /
    • 2009
  • This paper describes the radar tracking errors due to the presence of surface reflected waves. We investigate the previous studies on tracking errors and developed a tracking error estimation program using Matlab. We suggest an accurate error prediction method by considering the antenna beamwidth and surface reflection coefficient. The presented results well agree with theoretical predictions.