• Title/Summary/Keyword: Fluid feedback

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Force-feedback Control of an Electrorheological Haptic Device in MIS Virtual Environment (전기유변 유체를 이용한 햅틱 마스터와 가상의 최소침습수술 환경과의 연동제어)

  • Kang, Pil-Soon;Han, Young-Min;Choi, Seung-Bok
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.16 no.12 s.117
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    • pp.1286-1293
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    • 2006
  • This paper presents force-feedback control performance of a haptic device in virtual environment of minimally invasive surgery(MIS). As a first step, based on an electrorheological (ER) fluid and spherical geometry, a new type of master device is developed and integrated with a virtual environment of MIS such as a surgical tool and human organ. The virtual object is then mathematically formulated by adopting the shape retaining chain linked(S-chain) model. After evaluating reflection force, computational time, and compatibility with real time control, the virtual environment of MIS is formulated by interactivity with the ER haptic device in real space. Tracking control performances for virtual force trajectory are presented in time domain.

A Study on Control Characteristics of Fluid Power Elevator (유압식 엘리베이터의 제어특성에 관한 연구)

  • Yum, Man-Oh
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.2 no.3
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    • pp.41-47
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    • 2003
  • In this study an elevator plant model is made with an electro-hydraulic servo valve and a single rod cylinder. A PID controller, a velocity feedback PID controller and a MRAC controller ate designed. Experimental apparatus including an elevator plant model and these controllers are constructed. In case of experiment, external load which is made with a hydraulic cylinder and a pressure control valve burdens varying load to the elevator plant model being driven. With experiment, the control performances of three proposed control methods are compared.

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Force Control of a Pneumatic Driving System With a Long Transmission Line (전달관로를 고려한 공기압 구동장치의 힘 제어에 관한 연구)

  • Jang, J.S.
    • Transactions of The Korea Fluid Power Systems Society
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    • v.8 no.3
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    • pp.8-13
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    • 2011
  • In the present study, a robust controller has been designed to control force for a pneumatic driving system considering the effect of a transmission line. Transfer characteristics of pneumatic transmission line should be changed according to the velocity of the air going through the transmission line. The designed controller is composed of two parts. The one is a feedback controller, which is composed of a stabilizing filter, a compensating filter of modelling error and a nominal model of the force control system, to compensate the influence of transmission line and improve the feedback characteristics of the control system, and, the other is a feedforward controller to achieve the control performance. Control results with the designed controller show that the robustness and performance of the control system are improved compared to the control results with a fixed gain controller.

Position Control of a 1/4 Car Suspension Simulator using a Feedback Linearization Controller (피드백 선형화 제어기를 사용한 1/4 차량 현가장치 시뮬레이터의 위치 제어)

  • Kim, T.H.;Lee, I.Y.
    • Journal of Drive and Control
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    • v.9 no.3
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    • pp.8-15
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    • 2012
  • In the study, a control strategy using a feedback linearization compensator and a disturbance observer was suggested and applied to a hydraulic control system for a vehicle suspension simulator. Although the hydraulic system has comparatively big external loads composed by constant and varying loads, it is ascertained that excellent control performances are obtained with the suggested control strategy.

Closed-loop active vibration control of a typical nose landing gear with torsional MR fluid based damper

  • Sateesh, B.;Maiti, Dipak K.
    • Structural Engineering and Mechanics
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    • v.31 no.1
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    • pp.39-56
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    • 2009
  • Vibration is an undesirable phenomenon in a dynamic system like lightly damped aerospace structures and active vibration control has gradually been employed to suppress vibration. The objective of the current investigation is to introduce an active torsional magneto-rheological (MR) fluid based damper for vibration control of a typical nose landing gear. They offer the adaptability of active control devices without requiring the associated large power sources. A torsional damper is designed and developed based on Bingham plastic shear flow model. The numerical analysis is carried out to estimate the damping coefficient and damping force. The designed damper is fabricated and an experimental setup is also established to characterize the damper and these results are compared with the analytical results. A typical FE model of Nose landing gear is developed to study the effectiveness of the damper. Open loop response analysis has been carried out and response levels are monitored at the piston tip of a nose landing gear for various loading conditions without damper and with MR-damper as semi-active device. The closed-loop full state feedback control scheme by the pole-placement technique is also applied to control the landing gear instability of an aircraft.

Pressure Control of a Pneumatic Conrol system with a long Transmission Line (긴 전달관로를 갖는 공압제어계의 압력 제어)

  • Jang, Ji-Seong;Lee, Kwang-Kuk;Choi, Myung-Soo
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.27 no.4
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    • pp.567-576
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    • 2003
  • In this study, a robust controller to control pressure in a pneumatic pressure vessel with a long transmission line is proposed. Frequency response of transmission line using compressible fluid is changed by the flowing state of the fluid. So, it a fixed gain controller designed based on a model supposed the flowing state to a specific state, the performance of the control system could be degraded because of the modelling error. The controller designed in this study is composed of two parts. One is a feedback controller to improve a feedback characteristics and to compensate the influence of the variation of transfer characteristics of a transmission line owing to the change of flowing state and the other is a feedforward controller to regulate command fallowing performance. The experimental results with the designed controller show that the robustness of the control system is achieved regardless of the change of the model or the transmission line. Therefore, the designed controller can be utilized for the Performance improvement of a Pressure control system with a long transmission line using compressible fluid.

Vibration Control of Hybrid Smart Structure Using ER Fluids and Piezoelectric Ceramics (전기점성유체와 압전세라믹을 이용한 복합지능구조물의 진동제어)

  • 윤신일;박근효;한상보
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.13 no.8
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    • pp.612-618
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    • 2003
  • A hybrid vibration control scheme using ER fluid and PZT patches is proposed. Dynamic characteristics of the beam embedded with the ER fluid can be controled by changing the strength of the electric field applied on the ER fluid, thus provides a mean to avoid the resonance. It was found that active vibration control of the structure embedded with ER fluid failed to suppress the vibration excited with broad band frequency due to the limited change of the dynamic characteristics of the structure. To compensate this limited effect of the control scheme with ER fluid alone, PPF control using PZT patches as sensors and actuators is added to construct a hybrid controller. Experimental results suggests that proposed hybrid controller is effective to suppress the additional resonance vibration that appears when each controller is used alone.

Role of Mass Inflow and Supernova Feedback on Nuclear Ring Star Formation

  • Moon, Sanghyuk;Kim, Woong-Tae;Kim, Chang-Goo;Ostriker, Eve C.
    • The Bulletin of The Korean Astronomical Society
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    • v.46 no.2
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    • pp.37.1-37.1
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    • 2021
  • Observations suggest the star formation in nuclear rings of barred galaxies proceeds episodically in time and sometimes asymmetrically in space. Existing theories and numerical simulations suggest that the episodic star formation is perhaps due to either supernova feedback combined with fluid instabilities or time-varying mass inflow rate. However, it has been challenging to discern what dominates in shaping the star formation history because the effects of the inflow and feedback are blended in global simulations of nuclear rings. To understand their effects separately, we construct semi-global models of nuclear rings, which treat the mass inflow rate as a model parameter. By running simulations with the inflow rates kept constant or oscillating in time, we find that the star formation rate (SFR) of the rings varies coherently with the inflow rate, while the feedback is responsible only for stochastic fluctuations of the SFR within a factor of two. The feedback instead plays an important role in maintaining the vertical dynamical equilibrium and setting the depletion time. While the asymmetry in the inflow does not necessarily lead to the asymmetry in the star formation, we find that the rings undergo a transient period of lopsided star formation when the inflow rate of only one dust lane is suddenly increased.

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