• Title/Summary/Keyword: Angle tracking observer

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Attitude Maneuver Control of Flexible Spacecraft by Observer-based Tracking Control

  • Hyochoong Bang;Oh, Choong-Seok
    • Journal of Mechanical Science and Technology
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    • v.18 no.1
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    • pp.122-131
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    • 2004
  • A constraint equation-based control law design for large angle attitude maneuvers of flexible spacecraft is addressed in this paper The tip displacement of the flexible spacecraft model is prescribed in the form of a constraint equation. The controller design is attempted in the way that the constraint equation is satisfied throughout the maneuver. The constraint equation leads to a two-point boundary value problem which needs backward and forward solution techniques to satisfy terminal constraints. An observer-based tracking control law takes the constraint equation as the input to the dynamic observer. The observer state is used in conjunction with the state feedback control law to have the actual system follow the observer dynamics. The observer-based tracking control law eventually turns into a stabilized system with inherent nature of robustness and disturbance rejection in LQR type control laws.

Software Resolver-to-Digital Converter for Compensation of Amplitude Imbalances using D-Q Transformation

  • Kim, Youn-Hyun;Kim, Sol
    • Journal of Electrical Engineering and Technology
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    • v.8 no.6
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    • pp.1310-1319
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    • 2013
  • Resolvers are transducers that are used to sense the angular position of rotational machines. The analog resolver is necessary to use resolver to digital converter. Among the RDC software method, angle tracking observer (ATO) is the most popular method. In an actual resolver-based position sensing system, amplitude imbalance dominantly distorts the estimate position information of ATO. Minority papers have reported position error compensation of resolver's output signal with amplitude imbalance. This paper proposes new ATO algorithm in order to compensate position errors caused by the amplitude imbalance. There is no need premeasured off line data. This is easy, simple, cost-effective, and able to work on line compensation. To verify feasibility of the proposed algorithm, simulation and experiments are carried out.

Development of an Automatic Steering-Control Algorithm based on the MPC with a Disturbance Observer for All-Terrain Cranes (외란 관측기를 이용한 모델 예견 기반의 전지형 크레인 자동조향 제어알고리즘 개발)

  • Oh, Kwangseok;Seo, Jaho
    • Journal of Drive and Control
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    • v.14 no.2
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    • pp.9-15
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    • 2017
  • The steering systems of all-terrain cranes have been developed with various control strategies for the stability and drivability. To optimally control the input steering angle, an accurate mathematical model that represents the actual crane dynamics is required. The derivation of an accurate mathematical model to optimally control the steering angle, however, is difficult since the steering-control strategy generally varies with the magnitude of the crane's longitudinal velocity, and the postures of the crane's working parts vary while it is being driven. To address this problem, this paper proposes an automatic steering-control algorithm that is based on the MPC (model predictive control) with a disturbance observer for all-terrain cranes. The designed disturbance observer of this study was used to estimate the error between the base steering model and the actual crane. A model predictive controller was used for the computation of the optimal steering angle, along with the use of the base steering model with an estimated uncertainty. Performance evaluations of the designed control algorithms were conducted based on a curved-path scenario in the Matlab/Simulink environment. The performance-evaluation results show a sound reference-path-tracking performance despite the large uncertainties.

Trajectory Tracking Controller for Semiconductor Equipment Motors based on PI Observer (PI 관측기 기반 반도체 장비 모터의 궤적 추종 제어기 설계)

  • Yun Seong Cho;Hyeon Jun Choi;Sang Min Jeon;Ji Hoon Shin;Jae Young Lee;Bum Joo Lee;Young Ik Son
    • Journal of the Semiconductor & Display Technology
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    • v.22 no.2
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    • pp.96-103
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    • 2023
  • This paper presents a robust position tracking controller for a motor used in semiconductor equipment, utilizing the motor angle measurement. Precise position control is challenging due to the presence of uncertainties in various motor applications. The proposed controller consists of a PD (Proportional-Derivative) controller and a PIO (Proportional-Integral Observer) to estimate the system's state and equivalent disturbance compensating for the uncertainties. Since the stability alternates as the observer gain increases, we have investigated it through the closedloop root locus under the system parameters change. The analysis has showed that the inertia of the motor is the main parameter that affects it, and by adjusting the control gain appropriately, the system can be rendered to be stable even when the inertia of the motor changes. The effectiveness of the proposed control algorithm is validated through computer simulations, followed by a comparison of its performance with the results of a previous study.

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Viewing Angle-Improved 3D Integral Imaging Display with Eye Tracking Sensor

  • Hong, Seokmin;Shin, Donghak;Lee, Joon-Jae;Lee, Byung-Gook
    • Journal of information and communication convergence engineering
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    • v.12 no.4
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    • pp.208-214
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    • 2014
  • In this paper, in order to solve the problems of a narrow viewing angle and the flip effect in a three-dimensional (3D) integral imaging display, we propose an improved system by using an eye tracking method based on the Kinect sensor. In the proposed method, we introduce two types of calibration processes. First process is to perform the calibration between two cameras within Kinect sensor to collect specific 3D information. Second process is to use a space calibration for the coordinate conversion between the Kinect sensor and the coordinate system of the display panel. Our calibration processes can provide the improved performance of estimation for 3D position of the observer's eyes and generate elemental images in real-time speed based on the estimated position. To show the usefulness of the proposed method, we implement an integral imaging display system using the eye tracking process based on our calibration processes and carry out the preliminary experiments by measuring the viewing angle and flipping effect for the reconstructed 3D images. The experimental results reveal that the proposed method extended the viewing angles and removed the flipping images compared with the conventional system.

Design of a Robust Position Tracking Controller for Flexible Joint Manipulator Using Motor Angle (모터 각도를 이용한 유연 관절 머니퓰레이터의 강인한 위치 추종 제어기 설계)

  • Lee, Sang-Myung;Kim, In-Hyuk;Son, Young Ik
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.63 no.9
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    • pp.1245-1247
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    • 2014
  • This paper presents a robust position tracking controller for motor-driven flexible joint manipulators using only the motor angle measurement. The control problem is not easy because the link position is hard to estimate in the presence of parameter uncertainties. The proposed controller consists of a feedback linearization controller (FLC) and two proportional-integral observers (PIOs) that estimate both system states including the link position and an equivalent disturbance for compensating the parameter uncertainties. Comparative computer simulations are conducted to demonstrate the effectiveness of the proposed control algorithm.

Seamless Viewing Control by User Movement Between Pyramid Sections in Desktop 3D Hologram Pyramid (데스크톱 3D 홀로그램 피라미드에서 피라미드 단면 사이 사용자 이동에 따른 끊김 없는(seamless viewing control) 뷰 생성)

  • Hwang, Sun-Ju;Nam, Yang-Hee
    • The Journal of the Korea Contents Association
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    • v.21 no.3
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    • pp.1-9
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    • 2021
  • The hologram pyramid is an application of floating holograms, allowing the observer to see three-dimensional holograms from various angles without wearing wearable devices. Due to the low cost and ease of manufacturing, it has been used in a wide variety of fields as diverse as education, prototyping, showcase, and etc. But, when the observer looks at the hologram from the place where each side of the hologram pyramid is connected, the hologram looks cut and distorted. Also, the observer can see the only hologram of angles viewed head-on from each side. In this paper, we propose a method of generating a hologram image corresponding to the observer's gaze angle by tracking the observer's position and conducting reverse distortion. It provide a hologram of the angle viewed by the observer without cutting and distortion. In addition, the existing method and the proposed method were applied and compared in the hologram pyramid.

Multimachine Stabilizer using Sliding Mode Observer-Model Following including CLF for Measurable State Variables

  • Lee, Sang-Seung;Park, Jong-Keun
    • Journal of Electrical Engineering and information Science
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    • v.2 no.4
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    • pp.53-58
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    • 1997
  • In this paper, the power system stabilizer(PSS) using the sliding mode observer-model following(SMO-MF) with closed-loop feedback (CLF) for single machine system is extended to multimachine system. This a multimachine SMO-MF PSS for unmeasureable plant state variable is obtained by combining the sliding mode-model following(SM-MF) including closed-loop feedback(CLF) with the full-order observer(FOO). And the estimated control input for unmeasurable plant sate variables is derived by Lyapunov's second method to determine a control input that keeps the system stable. Time domain simulation results for the torque angle and for the angular velocity show that the proposed multimachine SMO-MF PSS including CLF for unmeasurable plant sate variables is able to damp out the low frequency oscillation and to achieve asymptotic tracking error between the reference model state at different initial conditions and at step input.

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A Design of Model Predictive Control and Nonlinear Disturbance Observer-based Backstepping Sliding Mode Control for Terrain Following (지형 추종을 위한 모델 예측제어와 비선형 외란 관측기를 이용한 백스테핑 슬라이딩 모드 제어기법 설계)

  • Dongwoo Lee;Kyungwoo Hong;Chulsoo Lim;Hyochoong Bang;Dongju Lim;Daesung Park;Kihoon Song
    • Journal of the Korea Institute of Military Science and Technology
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    • v.27 no.4
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    • pp.495-506
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    • 2024
  • In this study, we propose the terrain following algorithm using model predictive control and nonlinear disturbance observer-based backstepping sliding mode controller for an aircraft system. Terrain following is important for military missions because it helps the aircraft avoid detection by the enemy radar. The model predictive control is used to replace the generating trajectory and guidance with the flight path angle constraint. In addition, the aircraft is affected to the parameter uncertainty and unknown disturbance such as wind near the mountainous terrain. Therefore, we suggest the nonlinear disturbance-based backstepping sliding mode control method for the aircraft that has highly nonlinearity to enhance flight path angle tracking performance. Through the numerical simulation, the proposed method showed the better tracking performance than the traditional backstepping method. Furthermore, the proposed method presented the terrain following maneuver maintaining the desired altitude.

INTEGRATED CONTROL SYSTEM DESIGN OF ACTIVE FRONT WHEEL STEERING AND FOUR WHEEL TORQUE TO IMPROVE VEHICLE HANDLING AND STABILITY

  • Wu, J.Y.;Tang, H.J.;Li, S.Y.;Zheng, S.B.
    • International Journal of Automotive Technology
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    • v.8 no.3
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    • pp.299-308
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    • 2007
  • This study proposes a two-layer hierarchical control system that integrates active front wheel steering and four wheel braking torque control to improve vehicle handling performance and stability. The first layer is a robust model matching controller (R-MMC) based on linear matrix inequalities (LMIs), which optimizes an active front steering angle compensation and a desired yaw moment control, and calculates reference wheel slip for the target wheel according to the desired yaw moment. The second layer is a moving sliding mode controller (MSMC) that can track the reference wheel slip in a predetermined time by commanding proper braking torque on the target wheel to achieve the desired yaw moment. Since vehicle sideslip angle measurement is difficult to achieve in practice, a sliding mode observer (SMO) that requires only vehicle yaw rate as the measured input is also developed in this study. The performance and robustness of the SMO and the integrated control system are demonstrated through comprehensive computer simulations. Simulation results reveal the satisfactory tracking ability of the SMO, and the superior improved vehicle handling performance, stability and robustness of the integrated control vehicle.