• 제목/요약/키워드: hydraulic dead-zone

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사역대가 포함된 유압 위치 시스템의 LQG/LTR 제어 (LQG/LTR Control of Hydraulic Positioning System with Dead-zone)

  • 김인수;김영식;김기범
    • 한국소음진동공학회논문집
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    • 제22권8호
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    • pp.729-735
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    • 2012
  • A LQG/LTR(linear quadratic Gaussian/loop transfer recovery) controller with an integrator is designed to control the electro-hydraulic positioning system. Without considering the nonlinearity in the dead-zone, computer simulations are performed and show good performances and tracking abilities with the feedback controller based on the linear system model. However, the performance of the closed loop hydraulic positioning system shows big steady-state error in real system because of the dead-zone. In this paper, the feedback controller with a nonlinear compensator is introduced to overcome the dead-zone phenomenon in hydraulic systems. The inverse dead-zone as a nonlinear compensator is used to cancel out the dead-zone phenomenon. Experimental tests are performed to verify the performance of the controller.

사역대가 포함된 유압 위치 시스템의 LQG/LTR 제어 (LQG/LTR Control of Hydraulic Positioning System with Dead-zone)

  • 김기범;김영식;김인수
    • 한국소음진동공학회:학술대회논문집
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    • 한국소음진동공학회 2012년도 춘계학술대회 논문집
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    • pp.614-619
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    • 2012
  • A LQG/LTR(Linear Quadratic Gaussian/Loop Transfer Recovery) controller with an integrator is designed to control the electro-hydraulic positioning system. Without considering the nonlinearity in the dead-zone, computer simulations are performed and show good performances and tracking abilities with the feedback controller based on the linear system model. However, the performance of the closed loop hydraulic positioning system shows big steady-state error in real system because of the dead-zone. In this paper, the feedback controller with a nonlinear compensator is introduced to overcome the dead-zone phenomenon in hydraulic systems. The inverse dead-zone as a nonlinear compensator is used to cancel out the dead-zone phenomenon. Experimental tests are performed to verify the performance of the controller.

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정수지내 사류지역이 수리학적 효율에 미치는 영향 연구 (The Effect of Dead Zone on Hydraulic Efficiency in Clearwell)

  • 이승재;신은허;김성훈;박희경
    • 상하수도학회지
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    • 제21권2호
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    • pp.177-185
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    • 2007
  • Hydraulic efficiency($T_{10}/T$) in clearwell is often estimated by L/W ratio. However, this estimation is not accurate because other factors which give an effect on hydraulic efficiency such as shape of basin, diffuser wall and intra-basin is ignored. Therefore, in this research, hydraulic efficiency is predicted by the quantitative analysis of dead zone using CFD simulation in a pilot scale clearwell. The results show that the reason why higher L/W ratio increase the hydraulic efficiency is to decrease the dead zone of linear region which is located between baffles. Diffuser wall or intra-basin also affects on hydraulic efficiency with this process. Also, we conclude that hydraulic efficiency can not be reached to 0.8 or higher.

인공습지 기본형상에서 전산유체역학을 이용한 사류구간 및 입자제거율 평가 (Evaluation of hydraulic dead-zone and particle removal efficiency in the base frame of a constructed wetland using computational fluid dynamics)

  • 최영균;박민철
    • 상하수도학회지
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    • 제27권4호
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    • pp.495-502
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    • 2013
  • Hydraulic dead-zone and particle removal efficiency in the base frame of a constructed wetland was evaluated with computational fluid dynamics (CFD). The fraction of hydraulic dead-zone was estimated to be 1.2-2.1 % (v/v) and it was attributed to the artificial islands developed in the constructed wetland. Solids deposition rate could be increased with higher hydraulic retention time (HRT, ranged from 2.2 to 4.2 hr) of the wetland and larger particle size (ranged from 10 to $50{\mu}m$) in the influent. Experimental results showed that the volume concentration of the particles smaller than $10{\mu}m$ in diameter was varied from $1.99{\times}10^3{\mu}m^3/ml$ (HRT 12.8 hr) to $3.92{\times}10^3{\mu}m^3/ml$(HRT 2.2 hr) in the influent of the constructed wetland. With the effluent volume concentration data, removal efficiency of those particles was calculated to be 71.2 and 24.7 % when the HRT was 12.8 and 2.2 hr, respectively. Similar trend with the HRT variation could be identified with CFD analysis.

유전 알고리즘을 이용한 유압 위치계의 PID 제어기 동조 (Tuning of PID Controller for Hydraulic Positioning System Using Genetic Algorithm)

  • 김기범;박승민;김인수
    • 한국기계가공학회지
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    • 제15권3호
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    • pp.93-101
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    • 2016
  • This study presents a simple genetic algorithm to systematically design a PID controller for a hydraulic positioning system operated by a proportional solenoid valve. The inverse dead-zone compensator with nonlinear characteristics is used to cancel out the dead-zone phenomenon in the hydraulic system. The object function considering overshoot, settling time, and control input is adopted to search for optimal PID gains. The designed PID controller is compared with the LQG/LTR controller to check the performance of the hydraulic positioning system in the time and frequency domains. The experimental results show that the hydraulic servo system with the proposed PID controller responds effectively to the various types of reference input.

Adaptive Control of a Single Rod Hydraulic Cylinder - Load System under Unknown Nonlinear Friction

  • Lee Myeong-Ho;Park Hyung-Bae
    • Journal of Advanced Marine Engineering and Technology
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    • 제29권3호
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    • pp.251-259
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    • 2005
  • A discrete time model reference adaptive control has been applied in order to compensate the nonlinear friction characteristics in a hydraulic proportional position control system. As nonlinear friction, static and coulomb friction forces are considered and modeled as dead zone and external disturbance respectively. The model reference adaptive control system consists of a cascade combination of the dead zone. external disturbance and linear dynamic block. For adaptive control experiment. the DSP(Digital Signal Processor) board has been interfaced the hydraulic proportional position control system. The experimental results show that the MRAC(Model Reference Adaptive Control) for compensation of static and coulomb friction are very effective.

유공벽을 이용한 우류식 염소접촉조 사류 저감 방안 연구 (Study on Methodology for Reducing Dead Zone Flow within Chlorine Contactor Installing Porous Baffles)

  • 박현오;박노석;차민환;김사동;원찬희
    • 상하수도학회지
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    • 제24권5호
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    • pp.519-525
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    • 2010
  • From the results of tracer test for the existing chlorine contactor in Y water treatment plant, $T_{10}$ and $T_{10}$/T were calculated as 130 min and 0.16, respectively. Therefore it required the modification schemes for improving hydraulic efficiency, surrogated by T10 and $T_{10}$/T, and disinfection performance. In this study, in order to reduce dead zone within contactor, the installation of porous baffles in the near of each corner was suggested and verified using transient CFD(Computational Fluid Dynamics) simulation technique and tracer tests on dynamic condition. From the results of simulation and tracer tests, it was revealed that porous baffles installed have been effective to reduce dead zone within contactor, and increase plug flow fraction.

주파수역 성능을 고려한 유압 위치시스템의 강인 적응 제어 (Robust Adaptive Control of Hydraulic Positioning System Considering Frequency Domain Performance)

  • 김기범;김인수
    • 한국생산제조학회지
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    • 제23권2호
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    • pp.157-163
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    • 2014
  • In this paper, a robust MRAC (model reference adaptive control) scheme is applied to control an electrohydraulic positioning system under various loads. The inverse dead-zone compensator in the control system cancels out the dead-zone response, and an integrator added to the controller provides good position-tracking ability. LQG/LTR (linear quadratic Gaussian control with loop transfer recovery) closed-loop model is used as the reference model for learning the MRAC system. LQG/LTR provides a systematic technique to design the linear controller that optimizes the objective function using some compromise between the control effort and the system performance in the frequency domain. Different external load tests are performed to investigate the effectiveness of the designed MRAC system in real time. The experimental results show that the tracking performance of the proposed system is highly accurate, which offers considerable robustness even with a large change in the load.

Simulator for Hydraulic Excavator

  • Lim, Tae-Hyeong;Lee, Hong-Seon;Yang, Soon-Yong
    • 제어로봇시스템학회:학술대회논문집
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    • 제어로봇시스템학회 2005년도 ICCAS
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    • pp.2071-2075
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    • 2005
  • Hydraulic excavators have been popular devices in construction field because of its multi-workings and economic efficiency. The mathematical models of excavators have many nonlinearities because of nonlinear opening characteristics and dead zone of main control valve, oil temperature variation, etc. The objective of this paper is to develop a simulator for hydraulic excavator using AMESim. Components and whole circuit are expressed graphically. Parameters and nonlinear characteristics are inputted in text style. The simulator can be used to forecast excavator behavior when new components, new mechanical attachments, hydraulic circuit changes, and new control algorithm are applied. The simulator could be a kind of development platform for various new excavators.

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굴삭기용 Hardware In the Loop System(HILS) 개발 (Development of Hardware In the Loop System(HILS) for Hydraulic Excavator)

  • 임태형;조현철;안태규;양순용;이홍선
    • 한국공작기계학회:학술대회논문집
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    • 한국공작기계학회 2004년도 추계학술대회 논문집
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    • pp.468-473
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    • 2004
  • This paper deal with basic concept of Hardware In the Loop System(HILS) for hydraulic excavator. Hydraulic excavator has many nonlinearities because of P-Q diagram, dead zone and saturation of valve, single acting cylinder, heavy manipulator. So, actual test is needed when new component or control algorithm is developed but many restrictions exist. Hydraulic circuit of excavator is too complex to model mathematically but dynamic equation of manipulator has made good progress in previous studies. Basic concept of HILS and AMESim model of hydraulic components is contained in this paper.

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