• Title/Summary/Keyword: Closed-Loop Pitch System

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Position Control of a 3 dof Closed -loop Cylinder System Using ER Valve Actuators

  • Park, Seug-Bok;Cho, Myung-Soo
    • International Journal of Precision Engineering and Manufacturing
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    • v.2 no.2
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    • pp.48-56
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    • 2001
  • This paper presents the position tracking control of a closed-loop cylinder system using electro-rheological (ER) valve actuators. After manufacturing three sets of cylindrical ER valves on the basis of Bingham model of ER fluid, a 3 dof(degree-freedom) closed-loop cylinder system having the heave, roll and pitch motions is constructed. The governing equations of motion are derived using Lagrange's equation and a control model is formulated by considering nonlinear characteristics of the system, Sliding mode controllers are the designed for these ER valve actuators in order to achieve position tracking control. The effectiveness of trajectory tracking control performance of the proposed cylinder system is demonstrated through computer simulation and experimental implementation of the sliding mode controller.

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Position Control of a 3 dof Closed-loop Cylinder System Using ER Valve Actuators (ER 밸브 작동기를 이용한 3자유도 폐회로 실린더 시스템의 위치제어)

  • 최승복;조명수
    • Journal of the Korean Society for Precision Engineering
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    • v.17 no.3
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    • pp.165-173
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    • 2000
  • This Paper presents the position tracking control of a closed-loop cylinder system using electro-rheological(ER) valve actuators. After manufacturing three sets of cylindrical ER valves on the basis of Bingham model of ER fluid, a 3 dof(degree-of-freedom) closed-loop cylinder system having the heave, roll and pitch motions is constructed. The governing equations of motion are derived using Lagrange's equation and a control model is formulated by considering nonlinear characteristics of the system. Sliding mode controllers are then designed fer these ER valve actuators in order to achieve position tracking control. The effectiveness of trajectory tracking control performance of the proposed cylinder system is demonstrated through computer simulation and experimental implementation of the sliding mode controller.

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Power Regulation of Variable Speed Wind Turbines using Pitch Control based on Disturbance Observer

  • Joo, Young-Jun;Back, Ju-Hoon
    • Journal of Electrical Engineering and Technology
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    • v.7 no.2
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    • pp.273-280
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    • 2012
  • Most variable speed wind turbines have pitch control mechanisms and one of their objectives is to protect turbines when the wind speed is too high. By adjusting pitch angles of wind turbine, the inlet power and the torque developed by the turbine are regulated. In this paper, the difference between the real wind speed and its rated value is regarded as a disturbance, and a component called disturbance observer (DOB) is added to the pre-designed control loop. The additional DOB based controller estimates the disturbance and generates a compensating signal to suppress the effect of disturbance on the system. As a result, the stability and the performance of the closed loop system guaranteed by an outer-loop controller (designed for a nominal system without taking into account of disturbances) are approximately recovered in the steady state. Simulation results are presented to verify the performance of the proposed control scheme.

Study on Properties of Pitch Control for Wind Turbine (풍력터빈의 피치 PI 제어기 특성 고찰)

  • Lim, Chae-Wook
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.35 no.1
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    • pp.59-65
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    • 2011
  • The aerodynamic power and torque of wind turbines are extremely nonlinear. Therefore, the overall dynamic behavior of a wind turbine exhibits nonlinear characteristics that are dependent on the magnitude of the wind speed. The nonlinear aerodynamic characteristics of the wind turbine also affect the characteristics of the control system of the wind turbine. Therefore, the analysis of the nonlinear aerodynamic characteristics of wind turbine is essential in designing the wind-turbine controller. In this study, the nonlinear aerodynamic characteristics and the effects of these characteristics on the closed-loop pitch system with PI controller for an 1-mass model of the wind turbine are investigated above rated power.

A study on the 3-axis attitude stabilization of Koreasat (무궁화 방송통신 위성의 3축 자세 안정화 장치에 관한 연구)

  • 진익민;백명진;김진철
    • 제어로봇시스템학회:학술대회논문집
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    • 1993.10a
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    • pp.793-798
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    • 1993
  • In this study the attitude control of the KOREASAT is investigated. The KOREASAT is a geostationary satellite and its 3 attitude angles, namely, roll, pitch and yaw angles, are stabilized by using the 3-axis stabilization technique. In the pitch control loop, the pitch attitude angle received from the earth sensor is processed in the attitude processing electronics by using PI type control logic, and the control command is sent to the momentum wheel assembly to generate the control torque by varying the wheel rate. The roll/yaw attitude control is performed by activating a magnetic torquer or by firing appropriate thrusters. The magnetic torquer interacts with the earth magnetic field to produce the control torque, and the thrusters are used to control the larger roll attitude errors. In this study dynamic modelling of the satellite is performed. And the earth sensor, the momentum wheel, and the magnetic torquer are mathematically modelled. The 3-axis attitude control logic is implemented to make the closed-loop system and simulations are carried out to verify the implemented control laws.

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Integrated Roll-Pitch-Yaw Autopilot via Equivalent Based Sliding Mode Control for Uncertain Nonlinear Time-Varying Missile

  • AWAD, Ahmed;WANG, Haoping
    • International Journal of Aeronautical and Space Sciences
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    • v.18 no.4
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    • pp.688-696
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    • 2017
  • This paper presents an integrated roll-pitch-yaw autopilot using an equivalent based sliding mode control for skid-to-turn nonlinear time-varying missile system with lumped disturbances in its six-equations of motion. The considered missile model are developed to integrate the model uncertainties, external disturbances, and parameters perturbation as lumped disturbances. Moreover, it considers the coupling effect between channels, the variation of missile velocity and parameters, and the aerodynamics nonlinearity. The presented approach is employed to achieve a good tracking performance with robustness in all missile channels simultaneously during the entire flight envelope without demand of accurate modeling or output derivative to avoid the noise existence in the real missile system. The proposed autopilot consisting of a two-loop structure, controls pitch and yaw accelerations, and stabilizes the roll angle simultaneously. The Closed loop stability is studied. Numerical simulation is provided to evaluate performance of the suggested autopilot and to compare it with an existing autopilot in the literature concerning the robustness against the lumped disturbances, and the aforesaid considerations. Finally, the proposed autopilot is integrated in a six degree of freedom flight simulation model to evaluate it with several target scenarios, and the results are shown.

Wind Turbine Performance for Eigen Value Change of Closed-Loop System for PI-Controller (피치제어기 폐루프 시스템의 고유치 변화에 따른 풍력발전기의 성능)

  • Kim, Jong-Hwa;Moon, Seok-Jun;Shin, Yun-Ho;Won, Moon-Cheol
    • Journal of Wind Energy
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    • v.4 no.2
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    • pp.17-24
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    • 2013
  • Idealized PID-controlled rotor-speed error for blade pitch control of wind turbines responds as a second-order system with natural frequency and damping ratio for closed-loop system. RISO National Laboratory has recommended specific natural frequency(=0.6 rad/s) and damping ratio(=0.7) for 2 MW wind turbine. The baseline controller for 5 MW wind turbine of NREL(National Renewable Energy Laboratory) is designed based on the same values of RISO recommendation. This study investigates the effect of the natural frequency and damping ratio of the controller for NREL 5 MW wind turbine. It is confirmed that RISO recommendation shall be tuned for each wind turbine.

Position Control of 3 D.O.F. Cylinder Systems Using ER Valve Aetuators (ER밸브 작동기를 이용한 3자유도 실린더 시스템의 위치제어)

  • 조명수;조명수;김재환;정재천
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 1995.10a
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    • pp.565-568
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    • 1995
  • This paper presents the position control of a closed-loop cylinder system using ER(electro-rheological)valve actuators. Following the field-dependent pressure analysis of the ER valve actuators on the basis of Bingham model of ER fluids, a 3 d.o.f. close-loop sylinder system having the heave, roll and pitch motions is proposed. The governing equations of motion are derived using Lagrange's equation, and a control model is established by considering system uncertain parameters such as load conditions. A sliding mode controller which has inherent robustness to system uncertainties is adopted to achieve robust tracking control performance. Tracking control results for sinusoidal trajectory were presented in order to demonstrate the effectiveness of the proposed control system.

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Pitch-axis Maneuver of UAVs by Adaptive Control Approach (무인항공기의 적응제어 법칙을 이용한 피치 기동 연구)

  • Bang, Hyo-Choong
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.38 no.12
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    • pp.1170-1176
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    • 2010
  • This study addresses adaptive control of UAVs(Unmanned Aerial Vehicles) pitch-axis maneuver. The MRAC(Model Referenced Adaptive Control) approach is employed to accommodate uncertainties which are introduced by feedback linearization of pitch attitude control by elevator input. The model uncertainty is handled by adaptation laws which update model parameters while the UAV is under control by the feedback control law. Steady-state pitch attitude achieved by the stabilizing control law is derived to provide insight on the closed-loop behavior of the controlled system. The proposed idea is free of linearization, gain-scheduling procedures, so that one can design high maneuverability of UAVs for pitching motion in the presence of significant model uncertainty.

Adaptive Sliding Mode Control based on Feedback Linearization for Quadrotor with Ground Effect

  • Kim, Young-Min;Baek, Woon-Bo
    • Journal of Advanced Information Technology and Convergence
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    • v.8 no.2
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    • pp.101-110
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    • 2018
  • This paper introduces feedback linearization (FL) based adaptive sliding mode control (ASMC) effective against ground effects of the quadrotor UAV. The proposed control has the capability of estimation and effective rejection of those effects by adaptive mechanism, which resulting stable attitude and positioning of the quadrotor. As output variables of quadrotor, x-y-z position and yaw angle are chosen. Dynamic extension of the quadrotor dynamics is obtained for terms of roll and pitch control input to be appeared explicitly in x-y-z dynamics, and then linear feedback control including a ground effect is designed. A sliding mode control (SMC) is designed with a class of FL including higher derivative terms, sliding surfaces for which is designed as a class of integral type of resulting closed loop dynamics. The asymptotic stability of the overall system was assured, based on Lyapunov stability methods. It was evaluated through some simulation that attitude control capability is stable under excessive estimation error for unknown ground effect and initial attitude of roll, pitch, and yaw angle of $30^{\circ}$ in all. Effectiveness of the proposed method was shown for quadrotor system with ground effects.