• Title/Summary/Keyword: Fluid feedback

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Trajectory Tracking Control of Injection Molding Cylinder Driven by Speed Controlled Hydraulic Pump (속도제어-유압펌프에 의하여 구동되는 사출성형 실린더의 궤적추적제어)

  • Cho, S.H.
    • Transactions of The Korea Fluid Power Systems Society
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    • v.4 no.2
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    • pp.21-27
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    • 2007
  • This paper deals with the issue of trajectory tracking control of a clamping cylinder for injection moulding machine, which is directly driven by speed controlled hydraulic pump in combination with AC servomotor. As a fundamental step prior to tracking controller design, feedback control system is developed by implementing a position control loop parallel with a system pressure control loop. A sliding mode controller combining velocity feedforward scheme is developed for enhancing the tracking performance. Consequently a significant reduction in tracking error is achieved for both position and pressure control applications.

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Development of Control System of Twin-Fluid Nozzles for Controlling Spraying Rate and Droplet Size (이류체노즐을 이용한 분무량과 분무입경 제어시스템 개발)

  • 이중용;안형철;정창주
    • Journal of Biosystems Engineering
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    • v.25 no.1
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    • pp.11-18
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    • 2000
  • In precision chemical application increment of biological efficacy with less chemical is the virtue. spraying rate and droplet size is closely related to biological efficacy. this study was performed to develope a spray-control-system that could control spraying rate and droplet size independently. Twin-fluid nozzles were selected and tested to certify if the nozzles were suitable for the objective of this study. Characteritics of the nozzles i.e., spraying rte and droplet size change u8nder the changes of spraying pressure and air pressure were statistically modeled. The model had I to 1 matching property between dependent variables and independent variables. Using the property and the model, inverse relationship could be determined between variables. A feedback spray control system was developed and tested with predetermined error of 5 % in pressure. The system showed 4 % error in spraying rate and 9 % error in droplets size. Performance of the system could be upgraded by fine tuning but, in practical sense keeping air pressure in the field sprayer was the bottle neck of commercialization of the spray system.

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Path Control with Energy-Saving Load-Sensing for a Cylinder-Load System Using Speed-Controlled Fixed Displacement Pump (속도제어-정용량 펌프를 사용하는 실린더-부하계의 에너지절약-부하감지형 경로제어)

  • Cho, S.H.
    • Transactions of The Korea Fluid Power Systems Society
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    • v.6 no.3
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    • pp.16-22
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    • 2009
  • This paper deals with the issue of robust position tracking control and energy-saving control for a valve-controlled cylinder system using speed-controlled fixed displacement pump. The whole feedback control system is composed of a pair of interconnected subsystems, that is, valve-controlled cylinder system and load-sensing control system. From experiments it is shown that position tracking control in the load sensing control system can accomplish significant reduction in input energy to pump comparing to a conventional valve-controlled cylinder system, while exhibiting the same position tracking control accuracy.

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Dynamics and control of molten-salt breeder reactor

  • Singh, Vikram;Lish, Matthew R.;Chvala, Ondrej;Upadhyaya, Belle R.
    • Nuclear Engineering and Technology
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    • v.49 no.5
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    • pp.887-895
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    • 2017
  • Preliminary results of the dynamic analysis of a two-fluid molten-salt breeder reactor (MSBR) system are presented. Based on an earlier work on the preliminary dynamic model of the concept, the model presented here is nonlinear and has been revised to accurately reflect the design exemplified in ORNL-4528. A brief overview of the model followed by results from simulations performed to validate the model is presented. Simulations illustrate stable behavior of the reactor dynamics and temperature feedback effects to reactivity excursions. Stable and smooth changes at various nodal temperatures are also observed. Control strategies for molten-salt reactor operation are discussed, followed by an illustration of the open-loop load-following capability of the molten-salt breeder reactor system. It is observed that the molten-salt breeder reactor system exhibits "self-regulating" behavior, minimizing the need for external controller action for load-following maneuvers.

The Experiment of the Robust Multi-Variable Controller and the LQG/LTR Controller for the Stewart Platform

  • Joon, Heo-Seong;Woo, Ko-Dong;Chul, Han-Myung
    • 제어로봇시스템학회:학술대회논문집
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    • 2001.10a
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    • pp.147.4-147
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    • 2001
  • This work presents the robust controller and the LQG/LTR controller for the stewart platform. To simplify the dynamics we combine equation of the stewart platform and linearized one of hydraulic actuators not considered condensability of the fluid. Through the connection of two dynamic equations we can omit force feedback process of actuators and design controllers for the whole system. We applied two controllers on the stewart platform and show the adequacy controllers through the result of simulation and experiment.

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Modeling and Control of a Hydraulic Semiactive Vibration Absorber (유압식 반능동 진동 흡수기의 모델링과 제어)

  • 모창기
    • Journal of KSNVE
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    • v.8 no.4
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    • pp.700-705
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    • 1998
  • Recent past work has demonstrated that hydraulic semiactive vibration absorbers hold the promise of providing an ideal means of mitigating structural vibration. This paper examines a factor that must be treated when designing a hydraulic semiactive vibration absorber for application to a full scale structure; fluid compressibility. An expanded and consistent dynamic model of the flow process is first established. A simple feedback control is then tested on a single degree of freedom laboratory structure to verify the findings.

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The Method of Automathic Operation of Coagulant Dosage by the quality of water (수질에 따른 응집제 주입 자동운영 방안)

  • Jun, Uk-Pyo
    • 유체기계공업학회:학술대회논문집
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    • 2005.12a
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    • pp.278-283
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    • 2005
  • Generally Jar-Test is available to determine the coagulant dosage rate. Disadventages associated with Jar-Test are that regular samples have to be taken requiring manual intervention and the limitation to feedback control. To deal with this difficulty, determined optimized dosage rates of coagulant to investigates the union operation method of the statistical equation which uses the multi-regression method and the SCD.

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The Method of Optimum Operation of Coagulant Dosage Facility (응집제 주입설비 최적 운영방안)

  • Jun, Uk-Pyo;Oh, Sueg-Young
    • 유체기계공업학회:학술대회논문집
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    • 2004.12a
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    • pp.275-281
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    • 2004
  • Generally Jar-Test is available to determine the coagulant dosage rate. Disadventages associated with Jar-Test are that regular samples have to be taken requiring manual intervention and the limitation to feedback control. To deal with this difficulty, determined optimized dosage rates of coagulant to Investigates the union operation method of the statistical equation which uses the multi-regression method and the SCD.

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Vibration Control of Flexible Rotor Systems Using an Electro-rheological Fluid Damper (ER 유체 감쇠기를 이용한 유연 회전축 계의 진동제어)

  • Lim, Seung-Chul;Chae, Jeong-Jae;Park, Sang-Min;Yun, Eun-Gyu
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.12 no.5
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    • pp.365-373
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    • 2002
  • This paper concerns the design and application of an electro-rheological (ER) fluid damper to semiactive vibration control of rotor systems. In particular, the system under present study is constructed structurally flexible in order to explore multiple critical speeds within operation range. To this end, the dynamic models of the proposed ER damper and its associated amplifier are derived in the first place. Subsequently entire rotor system model is assembled along with the dynamics of the end effector based on a finite element method enabling prediction as to its free and forced vibration characteristics. Next, an artificial intelligent (AI) feedback controller is synthesized taking into account the peculiarity of Coulomb damping effect in rotor applications. Finally, computational and experimental results are presented including model validation and control performances. In practice, such an AI control proved effective whether the spin speed was either before or after critical speeds.

A Study on the Development of Mathematical Model of Three-stage Flow Control Valve

  • Khan, Haroon Ahmad;Kang, Chang Nam;Yun, So Nam
    • Journal of Drive and Control
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    • v.15 no.2
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    • pp.38-45
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    • 2018
  • In this study, the theory of fluid mechanics and dynamics is used to build a mathematical model for a three-stage flow control valve. The significance of the study is that the mathematical model can easily be used to study the effect of different design parameters on the performance of the valve. The geometry of the valve and the properties of the fluid were used in this study to determine the variation in the performance of the valve when varying the magnetic force on the pilot spool. While a linearization technique is not used to solve the developed model, the solution of the mathematical model is found in the time domain by simulation of the equations using a software package. The results indicate that if the developed mathematical model is solved for the different values of magnetic force, the valve behaves linearly; the valve is thus called the proportional flow control valve.