• Title/Summary/Keyword: 서보실린더

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A Study on the Oil Inertia Effect and Frequency Response Characteristics of a Servo Valve-Metering Cylinder System (서보밸브-미터링 실린더 시스템의 오일 관성효과와 주파수 응답 특성에 관한 연구)

  • Yun, Hongsik;Kim, SungDong
    • Journal of Drive and Control
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    • v.18 no.2
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    • pp.9-19
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    • 2021
  • The spool displacement signal of a directional control valve, including the servo valve, can be considered as the standard signal to measure dynamic characteristics. When the spool displacement signal is not available, the velocity signal of a metering cylinder piston can be used. In this study, the frequency response characteristics of the metering cylinder are investigated for the spool displacement input. The transfer functions of the servo valve-metering system are derived taking into consideration the oil inertia effect in the transmission lines. The theoretical results of the transfer functions are verified through computer simulations and experiments. The oil inertia effect in the transmission lines was found to have a very significant effect on the bandwidth frequency of the servo valve-metering cylinder system. In order to more precisely measure the dynamic characteristics of a servo valve, the metering cylinder should be set up to minimize the oil inertia effect by increasing the inner diameters of the transmission lines or shortening their lengths.

A study on the force control of a servo actuator with built-in MR Valve (MR 밸브 내장형 서보 액추에이터의 힘 제어에 관한 연구)

  • Ahn K.K.;Song J.Y.;Kim J.S.;Ahn Y.K.;Park J.H.
    • Transactions of The Korea Fluid Power Systems Society
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    • v.3 no.1
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    • pp.1-6
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    • 2006
  • A servo actuator with a valve using MR (Magneto-Rheological) fluid is proposed for fluid control systems. The MR fluid is well known as a functional fluid whose apparent viscosity is controlled by the applied magnetic field strength. The pressure in the MR cylinder can be controlled by the applied magnetic field strength. Good points of the MR cylinder are more simple, compact and reliable structure than a conventional oil hydraulic cylinder. The experimental results show that the MR cylinder could be used as a servo actuator.

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A Study on In-Process Performance Diagnosis of Hydraulic Servovalves - First Report : Position Control System - (유압서보밸브의 인-프로세스 성능 진단에 관한 연구 I - 유압실린더 위치제어계의 경우 -)

  • Kim S.D.;Kim K.H.;Song J.S.;Ham Y.B.;Lee J.C.
    • Transactions of The Korea Fluid Power Systems Society
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    • v.3 no.1
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    • pp.7-14
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    • 2006
  • In this paper, an in-process diagnosis method for performance of position control servo system was studied, which was based upon null bias, slew-rate ratio and delay time measurement. Slew-rate ratio and delay time were analyzed by theoretical analysis, computer simulation and experiment. As a result of these analysis, when spool of servovalve was weared, slew-rate ratio was decreased and delay time was increased.

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In-Process Diagnosis of Servovalve wear in Hydraulic Force Control Systems (유압실린더 힘 제어계의 인-프로세스 서보밸브 마모진단에 관한 연구)

  • Kim, S.D.;Jeon, S.H.;Chang, Y.
    • Transactions of The Korea Fluid Power Systems Society
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    • v.6 no.2
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    • pp.22-30
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    • 2009
  • An in-process method of diagnosing the spool wear of hydraulic servovalves was explored. The diagnostic method discussed in this paper is for force-control hydraulic servo systems. The key principle used is that pressure sensitivity of a servovalve drops as the valve spool wears out so that it is possible to determine the spool condition by monitoring pressure sensitivity. A diagnostic algorithm was developed and evaluated through numerical simulation and experiments. Two major steps of diagnosis are the evaluation of null bias of the servovalve and the approximation of pressure sensitivity, both of which could be successfully done during normal operation of a servo system. The difference between a new servovalve and a worn valve could be clearly detected in-process, and the diagnostic test was found to be repeatable.

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Study on Bandwidth Frequency of Servovalve based on Metering Cylinder (실린더를 이용한 서보 밸브 대역폭 주파수의 측정에 관한 연구)

  • Kim, S.D.;An, Wen-Long;Jeon, S.H.
    • Journal of Drive and Control
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    • v.12 no.3
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    • pp.44-51
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    • 2015
  • In this study, a metering cylinder was constructed, and the velocity obtained from the linear velocity transducer (LVT) of the cylinder piston was used to evaluate the dynamic performance of an electro-hydraulic servovalve. Frequency response experiments involving the spool displacement and piston velocity (LVT signal) were conducted with different input signal amplitudes, hydraulic pipe diameters, and supply pressures. The spool displacement signal accurately reflected the performance of the servovalve. Meanwhile, the -3 dB bandwidth frequency of the LVT signal was similar to the spool displacement signal, except for a small-amplitude input signal, and the $-90^{\circ}$ phase lag bandwidth frequency showed some differences.

A study on the position control of single rod cylinder servosystem using VSS (가변구조에 의한 편로드실린더서보계의 위치제어에 관한 연구)

  • 권기수;하석홍;허준영;이진걸
    • 제어로봇시스템학회:학술대회논문집
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    • 1989.10a
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    • pp.266-271
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    • 1989
  • In eliminating the nonliner charateristics such as piston displacement drift and difference in speeds of the reciprocating motion due to their nonsymetrical structure of single rod cylinder, modelling was carried out by additional outside disturbance, suggest the position control of single rod cylinder servosystem using VSS and compared with PD control of fixed structure system.

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A study on the position control of single rod cylinder servosystem using VSS (가변구조에 의한 편로드 실린더 서보계의 위치제어에 관한 연구)

  • 권기수;하석홍;허준영;이진걸
    • Journal of Advanced Marine Engineering and Technology
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    • v.16 no.1
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    • pp.27-34
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    • 1992
  • In eliminating the nonlinear characteristics such as piston displacement dift and difference in speeds of the reciprocating motion due to their nonsymetrical structure of single rod cylinder, the linear model can be given by equivalent outside disturbance, etc. The position control method of single rod cylinder servosystem using the sliding mode control of VSS was suggested and the good results without off-set are compared with PD control of fixed structure system.

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Development of the Hybrid Type Robot Using a Pneumatic Actuator For Physical Therapy Of Ankylosis (관절 경직 환자의 물리 치료를 위한 공압 구동형 하이브리드 로봇 개발)

  • 최현석;최철우;한창수;한정수
    • Journal of Biomedical Engineering Research
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    • v.24 no.2
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    • pp.127-132
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    • 2003
  • In this paper. the pneumatic service robot with a hybrid type is developed. A pneumatic has the advantages of good compliance , high Payload-to-weight and payload-to-volume ratios. high speed and force capabilities. Using pneumatic actuators. which have low stiffness. the service robot can guarantee safety. By suggesting a new serial-parallel hybrid type for the service robot which separates into Positioning motion and orienting motion, we can achieve large workspace and high strength-to-moving-weight ratio at the same time. A sliding mode controller can be designed for tracking the desired output using the Lyapunov stability theory and structural properties of pneumatic servo systems. Through many experiments of circular trajectory. the Pneumatic service robot is evaluated and verified.

Fault Diagnosis for High Pressure Turbine Valve using Fuzzy Logic (퍼지 논리를 이용한 원자력 발전소 고압터빈 밸브 고장진단)

  • Kim Yeon-Tae;Jeong Byeong-Uk;Baek Gyeong-Dong;Kim Seong-Sin
    • Proceedings of the Korean Institute of Intelligent Systems Conference
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    • 2006.05a
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    • pp.79-82
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    • 2006
  • 본 논문은 원자력 발전소의 주요 제어계통 중에서 터빈 조속기 제어계통에 관련한 성능평가를 목적으로 한다. 터빈 조속기 계통은 고압의 유압계통으로 구성되어 있어 구동설비가 복잡하다. 복잡한 기계설비는 운전 중 많은 오동작에 의한 고장을 일으키고, 유지보수에 어려움이 있다. 이러한 복잡한 기계설비에 있어 운전원에 의한 기계성능 평가는 불리한 점이 많다. 예를 들어 서로 다른 시간에서 일어나는 같은 상황에 대해 다른 판단을 내릴 수 있다는 점이다. 터빈 조속기 계통의 기계설비에 있어서 터빈 밸브 유압공급 및 구동장치는 각 터빈벨브 자체에 부착되어 있어 터빈벨브를 동작시킨다. 터빈벨브들은 구동기 유압 서보실린더(Actuator Hydraulic Servo Cylinder)에 의해 열리고 압축된 스프링에 의해 닫힌다. 이러한 시스템을 진단하기 위해서 본 논문에서는 밸브의 내부 압력의 특징정보를 입력으로 하는 퍼지이론을 적용하여 터빈 밸브 구동설비의 성능을 판단하고자 한다. 퍼지이론에 적용하기위해 터빈 조속기 제어계통의 고압 터빈 조절 벨브와 고압 터빈 정지 밸브의 압력변화 데이터를 이용한다. 퍼지이론의 적용과정에서 퍼지 Rule은 실제 운전원이 압력변화 데이터에 대한 판단기준을 근거로 하여 정하기로 한다. 그리고 퍼지이론에 적용한 결과를 분석하고 실제 터빈 조속기 계통의 전문가가 판단 결과와 비교하였다.

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A Study on a Development of the Grinding Robot to Remove Welding-bid of Working Pieces (취부용 피스(piece)제거 및 사상 작업 자동화장비 개발에 관한 연구)

  • Noh, Hyo-Won;Kim, Ki-Jung;Leem, Rae-Soo;Kim, Ho-Kyoung
    • Special Issue of the Society of Naval Architects of Korea
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    • 2008.09a
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    • pp.136-143
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    • 2008
  • This paper presents the application of a robot which aims at grinding automatically welding-bead remained in the removal job of working pieces for shipbuilding. In specific, the investigation on this application is composed of two parts; one topic is on the development of a robot platform vertically movable on a steel plate of hull, while the other topic is of the development of a grinding tool mechanism in order to remove welding-beads by using a diamond wheel installed on a servo cylinder (which can result in high working pressure on the grinding wheel). Besides, the development of a vision system for tracking welding-beads as well as recognizing welding surfaces is added for the convenience of this robot application to the removal of welding-beads remained in the working pieces for shipbuilding.

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