• Title/Summary/Keyword: Moment Compensator

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Development of Membrane Type Liquid Variable Compensator

  • Takahashi, Seiji;Ochiai, Makoto;Hayakawa, Yoshinori
    • Proceedings of the Korean Society of Medical Physics Conference
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    • 2002.09a
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    • pp.183-185
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    • 2002
  • Heavy ion and proton therapy necessitate range weeks, which are time consuming. Three types of variable compensator, membrane type liquid variable compensator, are proposed by some of the authors to overcome the difficulties, by those arbitrarily thickness distribution of compensator obtained from treatment planning is created at the site of treatment. None of the ideas, however, is yet realized. In this research, we are trying to construct prototype membrane-type liquid variable compensator. This variable compensator partitions air and liquid with elasticity membrane and changes the surface of the elasticity membrane with the thread. The air and oil move through holes to and from the out of beam side of two boxes in which they are contained. The boxes are made of Plexiglas(PMMA), the thread which is made of nylon, the elasticity film which is made from latex for the moment.

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A Study on the Reduction of the Torsional Angular Acceleration on Chain Drive Wheel of Marine Diesel Engine

  • Kim, Sang-Jin;Kim, Jung-Ryul
    • Journal of Advanced Marine Engineering and Technology
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    • v.31 no.3
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    • pp.215-223
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    • 2007
  • When the propulsion shafting system of marine diesel engine is designed. the vibratory stresses on shafts should be reviewed and be satisfied with limits which are laid down by classification societies In addition. the torsional vibration aspects for crankshaft of main engine are requested to be checked by engine designers. Especially. for the 4, 5, and 6-cylinder engines. the 2nd order moment compensator(s) may be installed to compensate the external moments of engine and not to excite the hull girder vibration. This moment compensator which is mounted on fore and/or after-end of engine is driven by the roller chain drive for some of MAN 2-stroke diesel engines. While the engine is running, the roller chain Is worn down, which causes the extension of roller chain. The chain therefore should be checked and tightened by periods in order to keep its functionality. However. when the torsional angular acceleration of chain drive exceeds the certain limit. the chain will suffer the excessive slack and transverse vibration. This may cause fatigue, wear or damage on the chain and the chain ultimately may be broken. The research object of this thesis is to review factors which affect the angular acceleration of chain drive and to find out how to decrease the angular acceleration of driving chain by checking factors which have a major contribution to acceleration reduction using the statistical method of DOE(design of experiment), correlation analysis and regression analysis methods.

An Optimal Design Study of an Equilibrating-Mechanism for the Unbalanced Elevation-Drive System (정적 불균형 모멘트가 존재하는 고저구동장치의 평형 메카니즘 최적설계 연구)

  • Park, Keun-Kuk;Lee, Man-Hyung;Kim, Dong-Hyun;Ahn, Rae-Young
    • Journal of Institute of Control, Robotics and Systems
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    • v.6 no.11
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    • pp.1033-1038
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    • 2000
  • The unbalanced heavy-loaded elevation-drive system is composed of a hydraulic cylinder, a driving link-mechanism and an equilibrating-mechanism which compensate the static unbalanced moment of the elevation load. The Compensator for the unbalanced moment is composed of a hydrau-pneumatic accumulator and a hydraulic cylinder which act with the elevation cylinder together. Compensation of the variable static-unbalanced moment for the elevation-drive system is very difficult because these mechanisms imply highly nonlinear properties due to air conditioning characteristics and mechanical rotation of the link-mechanism. In this study, through the analysis of the already designed equilibrating-mechanism, the optimal design parameters of the equilibrating-mechanism is suggested.

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A Sliding Mode Controller Using Neural Network for Underwater Robot Manipulator (해저작업 로봇 매니퓰레이터를 위한 신경회로망을 이용한 슬라이딩 모드 제어기)

  • Lee, Min-Ho;Choi, Hyung-Sik
    • Journal of Institute of Control, Robotics and Systems
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    • v.6 no.4
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    • pp.305-312
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    • 2000
  • This paper presents a new control scheme using a sliding mode controller with a multilayer neural network for the robot manipulator operating under the sea which has large uncertainties such as the buoyancy and the added mass/moment of inertia. The multilayer neural network using the error back propagation loaming algorithm acts as a compensator of the conventional sliding mode controller to improve the control performance when the initial assumptions of uncertainty bounds are not valid. Computer simulation results show that the proposed control scheme gives an effective path way to cope with the unexpected large uncertainties in the underwater robot manipulator.

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Design of a Fuzzy Compensator for Balancing Control of a One-wheel Robot

  • Lee, Sangdeok;Jung, Seul
    • International Journal of Fuzzy Logic and Intelligent Systems
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    • v.16 no.3
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    • pp.188-196
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    • 2016
  • For the balancing control of a one-wheel mobile robot, CMG (Control Moment Gyro) can be used as a gyroscopic actuator. Balancing control has to be done in the roll angle direction by an induced gyroscopic motion. Since the dedicated CMG cannot produce the rolling motion of the body directly, the yawing motion with the help of the frictional reaction can be used. The dynamic uncertainties including the chattering of the control input, disturbances, and vibration during the flipping control of the high rotating flywheel, however, cause ill effect on the balancing performance and even lead to the instability of the system. Fuzzy compensation is introduced as an auxiliary control method to prevent the robot from the failure due to leaning aside of the flywheel. Simulation studies are conducted to see the feasibility of the proposed control method. In addition, experimental studies are conducted for the verification of the proposed control.

A Robust Neural Control of Robot Manipulator Operated Under the Sea (해저작업 로봇 매니퓰레이터의 강건한 신경망 제어기)

  • 박예구;최형식;이민호
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 1995.10a
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    • pp.337-341
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    • 1995
  • This paper presents a robust control scheme using a multilayer network for the robot manipulator operating under the sea which has large uncertainties such as the buoyancy and the added mass/moment of inertia. The multilayer neural network acts as a compensator of the conventional sliding mode controller to maintain the control performance when the initial assumptions of uncertainty bounds are not valid. By the computer simulation results, the proposed control scheme dose not effectively compensate large uncertainties, but also reduces the steady stare error of the conventional sliding mode controller.

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Disturbance Compensation Control Design far 2-DOF Gun Stabilization System with Gear Stiffness by Using FXLMS Algorithm (기어강성을 갖는 2-자유도 포신 안정화시스템에서 FXLMS 알고리즘을 이용한 외란 보상 제어기 설계)

  • Lim, Jae-Keun;Kang, Min-Sig
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2005.05a
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    • pp.488-493
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    • 2005
  • In gun stabilization systems, the torque comes from the unbalance mass of gun and the base acceleration is an important source of disturbance which degrades stabilization performance. Fatigue of gear train is another important factor affecting structural safety problems. In this paper, a feedback control gain is designed by optimal control weighting to difference between motor and gun velocity, and a feedforward controller using FXLMS algorithm is adopted to investigate those problems. Experimental results show that the feedforward compensator based on FXLMS can reduce the disturbance effects. The directional convergence property according to initial conditions of the FXLMS is also shown through experiments.

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Optimal Design Analysis of Link-Mechanism and Development of Control Performance Estimation Program for Unbalanced Heavy-Loaded Drive System (구동 링크기구 최적설계 분석 및 대부하 구동제어 성능추정 프로그램 개발)

  • Choi, Keun-Kug;Lee, Man-Hyung;Ahn, Tae-Young
    • Journal of the Korean Society for Precision Engineering
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    • v.16 no.6
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    • pp.7-13
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    • 1999
  • The unbalanced heavy-loaded elevation-driving system is composed of link-mechanism, hydraulic cylinder and compensator for the static unbalanced moment of the load. Control and compensation of elevation-driving system is very difficult because these mechanisms imply highly nonlinear properties due to hydraulic fluid characteristics and mechanical rotation of link-mechanism. In this study, through the analysis of the link-mechanism, the optimal design of the link-mechanism is suggested. Also to estimate the control performance of the unbalanced, heavy-loaded servo-controlled system, modeling and simulation of nonlinear system are carried out. To prove the validity of performance estimation program, simulation results are compared with the experimental results. Both results are similar, therefore this program will be helpful to study the improvement of the system control performance.

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A Study On Moment Estimator Using Disturbance Feedforward Compensator And Effective Disturbance Observer (외란 전향 보상기를 이용한 관성 추정기 및 효율적인 외란 관측기에 대한 연구)

  • Cho, Yong-Gyu;Kim, Min-Young;Kim, Joohn-Sheok
    • Proceedings of the KIEE Conference
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    • 2006.07b
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    • pp.976-977
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    • 2006
  • 선형전동기와 같은 선형운동을 하는 기기에서 원형운동을 하는 경우 속도가 0 이되는 부분에서 비선형적인 마찰력이 작용하며 이로 인한 운동괘적의 외곡 현상이 발생한다. 본 연구에서는 이러한 마찰력을 비롯한 모든 외란을 하나의 비선형적인 외란으로 간주하여 실용적으로 사용할 수 있는 간단한 형태의 외란 관측기를 제시한다. 또한 모든 외란 관측기에서 피할수 없는 문제의 하나인 전동기 관성(모멘트)의 변동 문제를 해결하기 위하여 제한적이지만 매우 효과적으로 관성을 추정해낼 수 있는 새로운 방법을 제안한다.

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