• Title/Summary/Keyword: Fluid feedback

Search Result 104, Processing Time 0.02 seconds

The design of low-power MR damper using permanent magnet (영구자석을 이용한 저전력형 MR 감쇠기의 설계)

  • Kim, Jung-Hoon;Oh, Jun-Ho
    • Proceedings of the KSME Conference
    • /
    • 2000.04a
    • /
    • pp.433-439
    • /
    • 2000
  • Lots of semi-active control devices have been developed in recent years because they have the best features of passive and active system. Especially, controllable magneto-rheological(MR) fluid devices have received significant attention in these area of research. The MR fluid is the material that reversibly changes from a free-flowing, linear viscous fluid to a semisolid with a controllable yield strength in milliseconds when exposed to a magnetic field. If the magnetic field is induced by moving a permanent magnet instead of applying current to a solenoid, it is possible to design a MR damper consuming low power because the power consumption is reduced at steady state. This paper proposes valve mode MR damper using permanent magnetic circuit that has wide range of operation with low power consumption and small size. To design a MR damper that has a large maximum dissipating torque and a low damping coefficient, a design parameter is adopted. The magnetic circuit, material of choke and choke type are selected experimentally with the design parameter. The behaviors of the damper are examined and torque tracking control using PID feedback controller is performed for step, ramp and sinusoidal trajectories.

  • PDF

Analysis of the Axisymmetric Hydro-Mechanical Deep Drawing Process by Using the Finite Element Method (유한 요소법을 이용한 축대칭 하이드로 미케니칼 디프 드로잉 공정의 해석)

  • 양동열;김한경;이항수;김경웅
    • Transactions of the Korean Society of Mechanical Engineers
    • /
    • v.16 no.5
    • /
    • pp.873-882
    • /
    • 1992
  • The study is concerned with the rigid-plastic element analysis for axisymmetric hydromechanical deep drawing in which the fluid flow influences the metal deformation. Due to the fluid pressure acting on the sheet material hydromechanical deep drawing is distinguished from the conventional deep drawing processes. In considering the pressure effect, the governing equation for fluid pressure is solved and the result is reflected on the global stiffness matrix. The solution procedure consists of two stages ; i.e., initial bulging of the sheet surface before the initiation of steady fluid flow in the flange and fluid-lubricated stage. The problem is decoupled between fluid analysis and analysis of solid deformation by deformation by iterative feedback of mutual computed results. The corresponding experiments are carried out for axisymmetric hydro-mechanical deep drawing of annealled aluminium sheet as well as for deep drawing. It has been shown from the experiments that the limit drawing ratio for hydro-mechanical deep drawing is improved as compared with deep drawing. The computed results are in good agreement with the experiment for variation of punch head and chamber pressure with respect to the punch travel and for distribution of thicknees strain. It is thus shown that the present method of analysis can be effectively applied to the analysis of axisymmetric hydro-mechanical deep drawing processes.

Vibration isolation with smart fluid dampers: a benchmarking study

  • Batterbee, D.C.;Sims, N.D.
    • Smart Structures and Systems
    • /
    • v.1 no.3
    • /
    • pp.235-256
    • /
    • 2005
  • The non-linear behaviour of electrorheological (ER) and magnetorheological (MR) dampers makes it difficult to design effective control strategies, and as a consequence a wide range of control systems have been proposed in the literature. These previous studies have not always compared the performance to equivalent passive systems, alternative control designs, or idealised active systems. As a result it is often impossible to compare the performance of different smart damper control strategies. This article provides some insight into the relative performance of two MR damper control strategies: on/off control and feedback linearisation. The performance of both strategies is benchmarked against ideal passive, semi-active and fully active damping. The study relies upon a previously developed model of an MR damper, which in this work is validated experimentally under closed-loop conditions with a broadband mechanical excitation. Two vibration isolation case studies are investigated: a single-degree-of-freedom mass-isolator, and a two-degree-of-freedom system that represents a vehicle suspension system. In both cases, a variety of broadband mechanical excitations are used and the results analysed in the frequency domain. It is shown that although on/off control is more straightforward to implement, its performance is worse than the feedback linearisation strategy, and can be extremely sensitive to the excitation conditions.

Static Analysis of Dedicated Proportional Flow Control Valve for IMV (굴삭기 IMV용 비례 유량제어밸브 정특성 해석)

  • Jung, Gyuhong
    • Journal of Drive and Control
    • /
    • v.15 no.4
    • /
    • pp.39-47
    • /
    • 2018
  • Recently, as environmental regulations for earth-moving equipment have been tightening, advanced systems such as electronic control, have been introduced for energy savings. An IMV (Independent Metering Valve) consisting of four 2-way valves, is an electro-hydraulic control systems that provides more flexible controllability, and potential for energy savings in excavators, when compared to the conventional 4-way spool valve system. To fully maximize use of an IMV, the bi-directional flow control valve that can regulate a large amount of flow in both directions, should be adopted. The hydraulic circuit of an IMV applied to an excavator from an overseas construction equipment company, reveals the flow control valve with the compound of proportional solenoid valve for first stage, and 2-way spool valve for the second stage. Moreover, the two spools are interconnected by a feedback spring, presumed to compensate for flow force acting on the second stage spool. This paper addresses the static analysis of flow control valve in an IMV to investigate the improvement of robustness, against flow force by the feedback spring. From the steady-state analysis of flow control valve model, it can be concluded that the feedback spring facilitates maintaining linearity of spool displacement for control input, and relatively constant flow for load disturbance.

Position control fo a flexible gantry robot arm using smart actuators (스마트 작동기를 이용한 갠트리형 유연로봇팔의 위치제어)

  • 한상수;최승복
    • 제어로봇시스템학회:학술대회논문집
    • /
    • 1997.10a
    • /
    • pp.1800-1803
    • /
    • 1997
  • This paper presents new feedback actuators to achieve an accurate position control of a flexible gnatry robot arm. the translational motion in the plane is generated by two d.c.motors and controlled by emplying elecor-rheological(ER) clutch acutators. The generated motion can be continuously controlled by controlling the intensity of lectric field imposed to the ER fluid domain which tunes the transmitted torque of the ER clutch. n the other hand, during control action of the translational motion a flexible arm attached to the moving mass produces undesirable oscillatins due to its inherent flexibility. The oscillations are actively suppressed by applying feedback voltages to piezoceramic acutators bonded on the surface of the flexible arm. The control electric fields to be applied to the ER clutch and the control voltage for the piezoceramic actuator are determined via the loop shaping esign procedures(LSDP) in the H.inf. control technique. Comsequently, an accuate positiion control at the end-point of the flexible am is achieved during planar motion.

  • PDF

Trajectory Tracking Control of Pneumatic Artificial Muscle Driving Apparatus based on the Linearized Model (공압 인공근육 구동장치의 선형화 모델 기반 궤적추적제어)

  • Jang, J.S.;Yoo, W.S.
    • Journal of Power System Engineering
    • /
    • v.10 no.3
    • /
    • pp.97-103
    • /
    • 2006
  • In this study, a position trajectory tracking control algorithm is proposed for a pneumatic artificial muscle driving apparatus composed of a actuator which imitates the muscle of human, a position sensor and a control valve. The controller applied to the driving apparatus is composed of a state feedback controller and disturbance observer. The feedback controller which feeds back position, velocity and acceleration is derived from the linear model of pneumatic artificial muscle driving apparatus. The disturbance observer is designed to improve trajectory tracking performance and to reduce the effect of model discrepancy. The effectiveness of the designed controller is proved by experiments and the experimental results show that the pneumatic artificial muscle driving apparatus with the proposed control algorithm tracks given position reference inputs accurately.

  • PDF

The use of load pressure feedback in designing the high performance electro-hydraulic speed controller for large inertia system (대부하 전기유압시스템의 부하압력 피이드백에 관한 연구)

  • 김영대;이대옥;심재운
    • 제어로봇시스템학회:학술대회논문집
    • /
    • 1987.10b
    • /
    • pp.358-363
    • /
    • 1987
  • It is widely noted that pressure feedback systems have been devised to damp the fluid resonance effectively in precision speed control-for large inertia system. A compensation technique preserving the natural output disturbance discrimination characteristics at lower frequencies is proposed The load pressure across positive displacement acceleration. The technique involves feeding back load differential pressure, sensed by pressure transducers, though a simple analog compensatory circuit (high pass filter). The effectiveness of the damping is determined by the filter time donstant and loop gain. Nonlinear total hydraulic simulation results verify the possibility of linear model predictions of extending the closed loop bandwidth beyond the uncompensated frequency.

  • PDF

Development of device measuring very high torque via torque arm with attached load cells (로드셀과 토크암을 이용한 대용량 토크 측정장치 개발에 관한 연구)

  • Lee, Y.B.;Han, S.H.
    • Transactions of The Korea Fluid Power Systems Society
    • /
    • v.7 no.1
    • /
    • pp.6-10
    • /
    • 2010
  • A measurement of very high torque for track drive unit in construction equipment is usually in difficulties due to the requirement of a torque meter with high capacity, and the limitation of geometry for an experimental set-up. To improve the troublesome problem, a new device was proposed, where a torque transmitted through the torque arm can be measured by load cells attached at each torque arm. The experimental set-up of the new device was carried out in order to measure the torque values for a mechanical feedback type planetary gear box, in which the power flow circulates itself in a closed-loop. The new device enables to measure torque values of 60,000Nm. Additionally, the measured values were estimated statistically in the aspect of their repeatability and reproducibility, so that an acceptable behaviour as a measuring device can be confirmed.

  • PDF

Position Control of an Electro Hydraulic Actuator Using Adaptive Control Method (적응제어 기법을 이용한 전기-유압 액츄에이터의 위치제어)

  • Cho, S.H.
    • Transactions of The Korea Fluid Power Systems Society
    • /
    • v.7 no.3
    • /
    • pp.1-6
    • /
    • 2010
  • This paper deals with the issue of simple adaptive position control for a pump-controlled cylinder system. A fixed displacement pump is utilized instead of servo valve and its speed is controlled by AC motor. The whole control system is composed of a pair of interconnected subsystems, that is, a feedback control system and a feedforward control system. From experiments it is shown that position control using simple adaptive control can accomplish significant reduction in position tracking error comparing to a conventional PID control.

  • PDF

A Study on the Damping Characteristics of a Hybrid Smart Structure Using Electrorheological Fluids and PZT (전기유동유체와 압전세라믹을 이용한 복합지능구조물의 감쇠특성 연구)

  • 윤신일;박근효;한상보;최윤대
    • Proceedings of the Korean Society of Machine Tool Engineers Conference
    • /
    • 2003.04a
    • /
    • pp.382-387
    • /
    • 2003
  • Many type of smart materials and control laws are available to actively adjust the structure from various external disturbances. Usually, a certain type of control law to activate a specific smart material is tell established, but the effectiveness of the control scheme is limited by the choice of the smart materials and the responses of the structure. ER fluid is adequate to provide small but arbitrary control forces at any point along the structure. It was found that active vibration control of the structure embedded with ER fluids fluidly to suppress the vibration excited with broad band frequency due to the limited change of the structure characteristics. To compensate this limited effect of the control scheme with ER fluid alone, PPF control using PZT as an actuator is added to construct a hybrid controller.

  • PDF