• Title/Summary/Keyword: Hydraulic machine

Search Result 337, Processing Time 0.025 seconds

Elasto-plastic Stress Analysis for Hydraulic Cylinders Tube of Thick wall (후벽 유압실린더 튜브의 탄소성 응력해석)

  • 김옥삼;김중현
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
    • /
    • 2000.10a
    • /
    • pp.647-652
    • /
    • 2000
  • This paper was utilized the STKM13C tubes for machine structural purposes model, inner radius was 100 mm and outer radios was 140 mm, axial length was semi-infinite and the isoparametric element was used. Radial, tangential and shearing stress occured the maximum stresses(-20, 52 and 26 MPa) at the inner radius and the minimum stresses at the outer radius. of the hydraulic actuator cylinders for an industrial systems. But negative signs have meaning compressive stress and stress diminution ratio was about 0.15 MPa/mm And then coincidence between the simulation and exact results(Lame' equation) is found to be fairly good, showing that the proposed analytical by BEM are reliable.

  • PDF

Capacity Design of Accumulator in Hydraulic Hybrid Drive Brake System (유압 하이브리드 구동 시스템의 축압기 용량 설계)

  • 이재구;김정현;김성동
    • Proceedings of the Korean Society of Machine Tool Engineers Conference
    • /
    • 2001.04a
    • /
    • pp.15-21
    • /
    • 2001
  • An accumulator in hydraulic systems stores kinetic energy during braking action, and then that controls hasty surge pressure. An energy recovery system using accumulator seems to be advantageous for ERBS due to its high energy density. This study suggests a method to decide suitable accumulator volume for ERBS. The method is based upon energy conservation between kinetic energy of moving inertia and elastic energy of accumulator. The energy conversion was analyzed and a simple formula was derived. A series of computer simulation was done to verify effectiveness of the formula. The results of the simulation work were compared with those of experiments and these results show that the proposed design is effective for decision accumulator volume in ERBS.

  • PDF

A Study on Morphological Analysis of the Rubbed Surface far Hydraulic Driving Material (유압구동 습동재의 마찰면 형상특징 해석에 관한 연구)

  • 전성재;조연상;김동호;박흥식
    • Transactions of the Korean Society of Machine Tool Engineers
    • /
    • v.11 no.1
    • /
    • pp.77-82
    • /
    • 2002
  • It is known that fractal theory has recently been used as a useful in the characterization of surface texture and the understanding of tribological phenomena such as friction wear and lubrication The fractal based method for describing the rubbed surface texture has aroused great interest In this paper the fractal descriptors was applied to rubbed surface of hydraulic driving material with image processing system in order to describe morphology of the rubbed surface The results showed that the fractal dimension can be determined by sum of intensity difference of surface pixel. The two step size to get fractal dimension is similar to surface roughness Ra. Fractal dimensions of the rubbed surfaces increase with an increase of applied load Morphology of the rubbed surface driving in lubricant can be effectively obtained by fractal dimensions.

Capacity Design of Accumulator in Hydraulic Regenerative Brake System (유압 재생 브레이크 시스템의 축압기 용량 설계)

  • 이재구;이재천;김정현;김성동
    • Transactions of the Korean Society of Machine Tool Engineers
    • /
    • v.11 no.1
    • /
    • pp.104-113
    • /
    • 2002
  • An accumulator in hydraulic systems stores kinetic energy during braking action and then that controls hasty surge pressure. An energy recovery system using accumulator seems to be advantageous far ERBS due to its high energy density. This study suggests a method to decide suitable accumulator volume far ERBS. The method is based upon energy conservation between kinetic energy of moving inertia and elastic energy of accumulator. The energy conversion was analyzed and a simple formula was derived. A series of computer simulation was done to verify effectiveness of the formu1a. The results of the simulation work were compared with those of experiments and these results show that the proposed design is effective far decision of accumulator volume in ERBS.

Trajectory Control of a Hydraulic Excavator using Adaptive-Robust Control Method (적응-강인 제어기법을 이용한 유압 굴삭기의 궤적 제어)

  • 최종환;김용석;김승수;양순용
    • Proceedings of the Korean Society of Machine Tool Engineers Conference
    • /
    • 2003.10a
    • /
    • pp.186-194
    • /
    • 2003
  • This paper proposes a combined controller frame of the adaptive robust control(ARC) and the sliding mode control(SMC) for the trajectory tracking control of the excavator to preserve the advantages of the both methods while overcoming their drawbacks, namely, asymptotic stability of adaptive system fir parametric uncertainties and guaranteed transient performance of sliding mode control for both parametric uncertainties and external disturbance. The suggested control technique is applied for the tracking of a straight-line motion of end-effector of manipulators, and through computer simulations, its trajectory tracking performances and the robustness to payload variation and uncertainties are illustrated.

  • PDF

Design of An Adaptive Force Control System for the Strip Caster (박판주조의 적응제어 시스템 설계)

  • 윤두형;허건수;변철울
    • Proceedings of the Korean Society of Precision Engineering Conference
    • /
    • 1997.04a
    • /
    • pp.766-771
    • /
    • 1997
  • In this strip casting,size of the roll separating force is a index representing the solidifying status of the melt. Rolling forces at the start of the casting process can change abruptly due to the overcooling of the leader strip. This inconsistensy leads to machine damage or deficient solidification which results in the failure of the casting. In this study, a mathematical model is derived for the hydraulic servo pressure control system for the twin roll strip caster and its parameters are estimated by the RLS algorithm. Based on the identified model, an one-step ahead predictive control method is applied in order to minimize the transient fluctuation of the rolling force. Its simulation results are compared with those of the conventional PI controllers.

  • PDF

Bucket Actuator Pressure Control by Independent Metering Valve for Excavator (독립제어 밸브에 의한 굴삭기 버켓 액추에이터 압력제어)

  • Yang, Joo-Ho;Jung, Tae-Rang
    • Journal of Power System Engineering
    • /
    • v.20 no.3
    • /
    • pp.36-42
    • /
    • 2016
  • A cylinder control system of the conventional construction machine has been controlled by hydraulic spool valves. This system is low-cost but system efficiency is not high. Recently, to improve this, all valves are controlled electronically and independently. Bu and Yao suggested four way electronic hydraulic control valve system. It is called IMVT(Independent Metering Valve Technology). The purpose of the study is to find proper IMV pressure control method for excavator and to validate excavator's bucket regeneration energy effect by controlling the IMV system. In this paper, we mathematically describe the bucket system of excavator first. And then, based on these results, we design the control system which is divided into two operations(none regeneration or regeneration).The results of the experiment show the desirable performance and usefulness of the designed control system.

Flow and Pressure Ripple Characteristics of Hydrostatic Transmissions (유압전동장치의 유량 압력맥동 특성)

  • 김도태;윤인균
    • Transactions of the Korean Society of Machine Tool Engineers
    • /
    • v.10 no.1
    • /
    • pp.120-126
    • /
    • 2001
  • This study deals with a flow and pressure ripple characteristics for a hydrostatic transmission(HST) consisting of a vari-able axial piston pump connected in an open loop to a fixed displacement axial piston motor. These flow ripples produced by pump and motor in HST interacts with the source impedances of the pump or motor and dynamic characteristics of the connected pipeline, and results in a pressure ripples, Pressure ripples. Pressure ripples in HSP is major source of vibration, which can lead to fatigue failure of components and cause noise. In this paper, the flow ripples generated by a swash plate type axial piston pump or motor in HST are measured by making use of hydraulic pipeline dynamics and the measured pressure data at two points along the pipeline. By using the self-checking functions, the validity of the method us investigated by comparison with the measured and estimated pressure ripples at the halfway section of the pipeline, and good agreement is achieved.

  • PDF

A Study on Stability of Excavator using ZMP (ZMP를 이용한 굴삭기의 안정성에 관한 연구)

  • Choi, Jong-Hwan;Um, Hyuk;Lim, Tae-Hyeong;Kim, Sung-Su;Yang, Soon-Yong;Lee, Byung-Ryong;Ahn, Kyung-Kwan
    • Proceedings of the Korean Society of Machine Tool Engineers Conference
    • /
    • 2003.04a
    • /
    • pp.86-92
    • /
    • 2003
  • The hydraulic excavator has been a popular research object for automation because of its multi-workings and economic efficiency. When it works crane tasks, most of disasters happen. The stability of the excavator having crane function has a close relation with excavators posture, motion and load. In this paper, the stability of tipping-over has been analysed using zero Moment point(ZMP)

  • PDF

전기 유압식 서어보 인덱싱 시스템의 위치 제어에 관한 연구

  • 안경관;진성무;이정오
    • Proceedings of the Korean Society of Precision Engineering Conference
    • /
    • 1992.04a
    • /
    • pp.385-389
    • /
    • 1992
  • The position control of the electro-hydraulic servo indexing system in a flexible forging machine was investigated. The role of an Electro-hydraulic servoindexing system is to rotate a workpiect fast and accurately to a desired position. Since the inertia of a workpiece changes during each forging step, an adapt control scheme could be adopted to the position control of the workpiece. A generalized predictive control method which depends on predicting the plant output over several steps ahead based on the assumption about future control actions is proposed. The perormance of the proposed GPC algorithm is investigated experimentally and compared with that of PID control. Experimental results show that the proposed GPC algorithm is satisfactory for the position control of the workpiece of an electrohydraulic indexing system.