• Title/Summary/Keyword: single rod hydraulic system

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Control Characteristics Improvement of Single Rod Hydraulic Cylinder Subjected to Varying Load (가변하중을 받는 유압실린더의 제어특성개선)

  • Yum, Man-Oh
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.2 no.4
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    • pp.46-52
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    • 2003
  • For position control of electro-hydraulic servo system, single rod cylinders and double rod cylinders are used. Single rod cylinders have simple structure for manufacturing but different volume ratio of two sides induce to non-linearity in process of then mathematical modeling. So only with conventional PID control method it is difficult to control single rod cylinders precisely. For mole precise position control of single rod cylinders, a controller which is inserted a velocity feedback PID controller and MRAC controller are proposed. With experiment control performances of three control methods are compared. In case of experiment, for external varying load to the system, a hydraulic cylinder and a pressure control valve are used. In conclusion a MRAC is considered a suitable control method for external varying load.

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Study for the Actuation of Lifter by the Bi-Directional Pump and Single-Rod Cylinder (양방향펌프와 편로드실린더에 의한 리프터의 구동에 관한 연구)

  • Lee, Seong-Rae;Kim, Je-Min
    • Transactions of the Korean Society of Automotive Engineers
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    • v.15 no.4
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    • pp.139-145
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    • 2007
  • The motion of single-rod cylinder is typically controlled by the directional control valve. In some case, the hydraulic system should be energized by the man power and at the same time the motion of a cylinder is controlled manually. It may be confusing for a man to do two things at the same time. The solution is to make up the closed hydraulic circuit with the bi-directional pump and single-rod cylinder without using a directional control valve. In the case of single-rod cylinder, the flows at the rod side and head side are so different that several valves should be installed to make the motion of single-rod cylinder possible. The hydraulic system is composed of a bi-directional pump, a single-rod cylinder, pilot operated check valves, a check valve and a counter balance valve for the purpose of actuating the lifter. The characteristics of a suggested system are analysized mathematically and numerically.

[ $H_{\infty}$ ] Optimal Control for Single-Rod Hydraulic Servo-System with DSP (DSP를 이용한 편로드 유압서보시스템의 $H_{\infty}$ 최적제어)

  • Jung, Gyu-Hong
    • Proceedings of the KSME Conference
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    • 2001.11a
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    • pp.515-520
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    • 2001
  • Due to the high power to weight ratio and fast response under heavy load, the hydraulic systems are still applied to the development of many industrial facilities such as heavy duty construction vehicles, aerospace/military weapon actuating systems and motion simulators. Unlike the other actuators, single-rod hydraulic cylinder exhibits a lot different dynamic characteristics between the extending and retracting stroke because of the difference in pressure acting areas. In this research, in order to overcome this nonlinear feature, $H_{\infty}$ optimal controller was designed and implemented with DSP board that was specifically developed for the experiment. From the experimental result, we could confirm that the overall performance of single-rod hydraulic servo system is similar with the results as we expected in the design stage.

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A Study on the Robust Position Control of Single-rod Hydraulic System (편로드 유압시스템의 강인 위치제어에 관한 연구)

  • Cho, Taik-Dong;Seo, Song-Ho;Yang, Sang-Min
    • Journal of the Korean Society for Precision Engineering
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    • v.16 no.3 s.96
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    • pp.128-135
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    • 1999
  • A driving simulators of aircraft and vehicle may consist of hydraulic power systems with many single-rod cylinders. The single-rod hydraulic systems are convenient but need more robust control scheme in order to achieve a reliable performance against the wide range of operating disturbances and the inherent model uncertainties. $H_{\infty}$ control scheme was implemented to the 2 degree-of-freedom hydraulic device similar to the simple driving simulator. With the reasonable disturbances from sensor, base and pump and also with the linearization of model, the simulation and experimental results showed good agreements.

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Improvement of a Hydraulic Circuit for an Electro-Hydrostatic Actuator Equipped with a Single Rod Cylinder (편로드 실린더 구동 EHA의 유압 회로 개선)

  • Hong, Yeh-Sun;Kim, Sang-Seok;Kim, Dae-Hyun;Kim, Sang-Beom;Park, Sang-Joon;Choi, Kwan-Ho
    • Journal of Aerospace System Engineering
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    • v.8 no.1
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    • pp.1-6
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    • 2014
  • The conventional hydraulic circuits for electro-hydrostatic actuators equipped with a single-rod cylinder can oscillate under overrunning load conditions. In this paper the oscillation problem encountered in the conventional hydraulic circuits for EHAs is analyzed and it is shown by simulation results that this problem can be solved by employing a counter balance valve instead of a pilot-operated check valve generally used in the conventional hydraulic circuits.

Study for the Energy Efficiency of Hydraulic System of Turnover-Type Sluice Gate (전도 수문용 유압장치의 에너지 효율에 관한 연구)

  • Lee, Seong-Rae
    • Proceedings of the KSME Conference
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    • 2007.05a
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    • pp.1225-1230
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    • 2007
  • The turnover-type sluice gate is typically actuated by the hydrauic system. The hydraulic system may be a open circuit type or a closed circuit type. The open circuit type hydraulic system is composed of a uni-directional pump, a directional control valve, pilot operated check valves, flow control valves, single-rod cylinders. The closed circuit type hydraulic system is composed of a bi-directional pump, pilot operated check valves, check valves, a counter balance valve, single-rod cylinders. The energy efficiencies of two hydraulic systems for the turnover-type sluice gate are compared here.

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Study for the Operational Characteristics of Closed Circuit Hydraulic System of Turnover-Type Sluice Gate (전도 수문용 폐회로형 유압장치의 작동 특성에 관한 연구)

  • Lee, Seong-Rae
    • Proceedings of the KSME Conference
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    • 2007.05a
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    • pp.897-902
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    • 2007
  • The turnover-type sluice gate is typically actuated by the open circuit hydrauic system since the single-rod cylinder is used rather than the double-rod cylinder. However, here the closed circuit hydrauic system is applied for the operation of turnover-type sluice gate for the purpose of convenient operation. The closed circuit hydraulic system of turnover-type sluice gate is composed of a bi-directional pump, single-rod cylinders, pilot operated check valves, check valves and a counter balance valve. The usefulness of the closed circuit hydraulic system is verified for the several operational conditions by the computer simulations.

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A study on digital control of the single-rod hydraulic cylinder using variable (가변구조이론을 이용한 편로드 유압실린더의 디지탈제어)

  • 이교일;김동춘
    • 제어로봇시스템학회:학술대회논문집
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    • 1991.10a
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    • pp.1133-1138
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    • 1991
  • A control of nonlinear system is motivated by the fact that all real plants are nonlinear systems and model identification introduces parameter errors. The purpose of this study is to design a Discrete Variable Structure Controller(DVSC) for single-rod hydraulic cylinder system. The model contains uncertain parameters which we known to lie upper and lower bounds. In the design of DVSC, the boundary layer concept was adopted to reduce cattering. The DVSC was evaluated through digital computer simulation and compared with a VSC (analog controller).

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Hybrid Self-Tuning Control of a Single rod Hydraulic Cylinder with Varying Payload (가변 하중을 갖는 편로드 유압 실린더의 합성 자기동조 제어)

  • Kim, M.S.;Kim, J.T.;Han, K.B.
    • Journal of the Korean Society for Precision Engineering
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    • v.14 no.12
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    • pp.174-181
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    • 1997
  • A proposed hybrid self-tuning control scheme for single rod hydraulic cylinder which has varying loads is presented here. An adaptive controller is developed for the system that use feedforward and P feedback control for simultaneous parameter identification and tracking control. Through experimental results, the performance comparison of the hybrid self-tuning controller with a constant gain P contro- ller clearly shows its superior ability in handling load changes in quiescent states.

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Self-Tuning Controller design for the motion control of a Single Rod Hydraulic Cylinder (편로드 유압실린더의 운동제어를 위한 자기동조 제어기설계)

  • 김정태;김문생
    • Journal of KSNVE
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    • v.8 no.3
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    • pp.441-449
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    • 1998
  • A self-tuning control scheme, incorporated with the simplified 1st-order ARMAX(Auto-Regressive Moving Average eXogenous) model, for single rod hydraulic cylinder which has varying dynamic characteristics is presented here. An adaptive controller is developed for the system that uses feedforward and optimal feedback control for simultaneous parameter identification and tracking control. Through experimental results, the performance comparison of the self-tuning controller with a fixed gain proportional controller clearly shows its superior ability in handling load changes in quiescent states.

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