• 제목/요약/키워드: Hydraulic measurement

검색결과 408건 처리시간 0.021초

수위관측과 수리학적 하도추적에 의한 수위-유량 관계식작성 (Determination of Stage-discharge Relations by Hydraulic Channel Routing and Stage Measurement)

  • 이상호
    • 한국수자원학회논문집
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    • 제34권5호
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    • pp.551-560
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    • 2001
  • 낙동강의 화원-교령교-현풍 수위관측소 구간에 대하여 수리학적 하도추적을 통하여 조도계수를 추정하였다. 세 관측소의 연속 수위자료와 하천 종횡단 측량자료만이 이에 사용되었다. 하도추적에 의해 계산된 유량자료로부터 수위-유량 관계식을 작성하였으며 이는 기존의 수위-유량 관계식보다 나은 결과를 보였다. 수위측정 오차가 유량계산에 미치는 영향에 대하여 분석하였으며, 측방유입류를 억제할 수 있도록 하도길이를 제한하는 방법도 제시하였다.

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플로우 펌프기법을 이용한 포천지역 화강 풍화토의 함수특성곡선 (Soil-Water Characteristic Curve of Weathered Granite Soils in Pocheon Area using Flow Pump Technique)

  • 이강일;이준용;백원진
    • 한국농공학회논문집
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    • 제51권1호
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    • pp.11-20
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    • 2009
  • Flow pump technique was used in order to determine the soil-water characteristic curve of weathered granite soils in Pocheon area. This technique enables measurement to be more convenient and accurate as it is based on the CU condition of triaxial compression test. Besides, it is also able to measure dry and moisture curves continuously since the test is controled by means of a computer automatically. In this study, not only a hydraulic conductivity of weathered granite soils at fully saturated state in Pocheon area, but also a soil-water characteristic curve throughout unsaturate flow tests were determined. In addition, Brooks and Corey's model and Genuchten's model were used to simulate the soil-water characteristic curve. On the basis of the simulation an unsaturate hydraulic conductivity was predicted.

전기 유압 서보 시스템의 비선형 외란 관측기 기반피드백 선형화 제어 (Disturbance Observer based Feedback Linearization Control for Electro-Hydraulic Servo Systems)

  • 원대희;김원희;정정주
    • 전기학회논문지
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    • 제64권2호
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    • pp.297-303
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    • 2015
  • We propose a disturbance observer(DOB) based feedback linearization control to improve position tracking performance in the presence of disturbance. The proposed method consists of a disturbance observer and a feedback linearization controller. The disturbance observer is designed to estimate the load force disturbance in electro-hydraulic systems. An auxiliary state variable is proposed in order to avoid amplification of the measurement noises in the disturbance observer. Using the estimated disturbance enables the Electro-hydraulic servo systems(EHS) dynamics to be changed into feedback linearization from. In order to compensate for the disturbance and to track the desired position, the feedback linearization based controller is proposed. The proposed method has a simple structure which can easily be implemented in practice. As a result, the proposed method improves the position tracking performance in the presence of disturbance. Its performance is validated via simulations.

Measurement of Fluid Film Thickness on the Valve Plate in Oil Hydraulic Axial Piston rumps (I) - Bearing Pad Effects -

  • Kim, Jong-Ki;Jung, Jae-Youn
    • Journal of Mechanical Science and Technology
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    • 제17권2호
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    • pp.246-253
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    • 2003
  • The tribological mechanism between the valve plate and the cylinder block in oil hydraulic axial piston pumps plays an important role on high power density. In this study, the fluid film thickness between the valve plate and the cylinder block was measured with discharge pressure and rotational speed by use of a gap sensor, and a slip ring system in the operating period. To investigate the effect of the valve plate shapes, we designed two valve plates with different shapes . the first valve plate was without a bearing pad, while the second valve plate had a bearing pad. It was found that both valve plates behaved differently with respect to the fluid film thickness characteristics. The leakage flow rates and the shaft torque were also experimented in order to clarify the performance difference between the valve plate without a bearing pad and the valve plate with a bearing pad. From the results of this study, we found out that in the oil hydraulic axial piston pumps, the valve plate with a bearing pad showed better film thickness contours than the valve plate without a bearing pad.

전달함수와 진동응답 측정에 의한 원심펌프에서의 유체력 특성에 관한 연구 (A Study on the Hydraulic Excitation Forces Using Transfer Function and Operational Measured Data for the Centrifugal Pump)

  • 최복록;박진무;김광은
    • 대한기계학회논문집A
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    • 제24권8호
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    • pp.1931-1939
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    • 2000
  • Operating excitation forces of the linear vibratory system are normally determined by direct measurement techniques using load cells, strain gauges, etc. But, hydraulic forces of the rotating turbomachinery such as centrifugal pumps are exerted on an impeller due to asymmety of the flow by the interaction between pump impeller and volute. So, investigations of wide range of hydraulic designs and geometric deviations are difficult by direct method. This paper presents a hybrid approach for fourier transformed operational excitation forces, which uses pseudo-inverse matrix of the transfer matrix for the system and the measured vibrational data with standard installed pump. The determination of the transfer function matrix is based on a linear rotor/stationary system and steady state harmonic response in finite element analysis. And, vibrational data is collected in both vertical and horizontal directions at inboard and outboard bearing housings. The results of the process may be enhanced by making acceleration measurements at many more locations than there are forces to be determined.

전립선 진단을 위한 수압 측정 방식의 새로운 요 유량 계측기법 (New uroflowmetry technique measuring hydraulic pressure for prostate diagnostics)

  • 김경아;최성수;차은종
    • 센서학회지
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    • 제16권3호
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    • pp.179-186
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    • 2007
  • Uroflowmetry is non-invasive and easily performed to diagnose benign prostate hypertrophy (BPH) frequent in aged men. Weight change during urination is usually measured to estimate the urinary flow rate by a load cell, but sensitive to any impacts against the bottom of the container, leading to unnecessary noise generation. Moreover, load cells are relatively expensive raising the production cost. The present study proposed a new technique, measuring hydraulic pressure on the bottom of the urine container to evaluate the urinary flow rate. Low cost pressure transducer enabled almost perfectly linear relationship between the urine volume and the hydraulic pressure. During both the simulated and human urination experiment, variance of the pressure signal was more than 50 % smaller than the weight signal acquired by a load cell, which demonstrated that the impact noise was decreased to a great degree by pressure compared to weight measurement.

DEVELOPMENT OF A FLOOD PROTECTION SYSTEM BY THE USE OF MODEL TESTS

  • Knoblauch Helmut;Goekler Gottfried;Heigerth Guenther
    • Water Engineering Research
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    • 제3권1호
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    • pp.45-55
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    • 2002
  • The Szentgotthard Flood Protection Project is located in the southeasters part of Austria, very close to the Hungarian border and to the Hungarian town of Szentgotthard situated near the Junction of the rivers Lafnitz and Raab. During heavy rainstorms, this area has always been liable to severe floodings, affecting the town itself and upstream reaches, where major industrial and commercial development is planned. In order to solve these problems, several solutions have been developed by means of a series of model tests performed at the hydraulic laboratory of the Technical University of Graz, Austria. The model was constructed to scales 1:75 (lengths) and 1:25 (heights). This trebled scale allowed greater accuracy in the measurement of discharge depths. The results from the model tests have led to the following proposals: - Construction of a flood relief trough with an inflow section 3.5 km upstream of the junction of the rivers Lafnitz and Raab. - Use of a former river bed for the flood relief trough. - Design of a lowered embankment crest section to pass one-third of the maximum flood flow of the river Lafnitz. - Connection of the flood relief trough to the Lahnbach stream, a tributary of the river Raab.

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Impact performance for high frequency hydraulic rock drill drifter with sleeve valve

  • Guo, Yong;Yang, Shu Yi;Liu, De Shun;Zhang, Long Yan;Chen, Jian Wen
    • International Journal of Fluid Machinery and Systems
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    • 제9권1호
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    • pp.39-46
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    • 2016
  • A high frequency hydraulic rock drill drifter with sleeve valve is developed to use on arm of excavator. In order to ensure optimal working parameters of impact system for the new hydraulic rock drill drifter controlled by sleeve valve, the performance test system is built using the arm and the hydraulic source of excavator. The evaluation indexes are gained through measurement of working pressure, supply oil flow and stress wave. The relations of working parameters to impact system performance are analyzed. The result demonstrates that the maximum impact energy of the drill drifter is 98.34J with impact frequency of 71HZ. Optimal pressure of YZ45 rock drill is 12.8 MPa-13.6MPa, in which the energy efficiency reaches above 58.6%, and feature moment of energy distribution is more than 0.650.

A data fusion method for bridge displacement reconstruction based on LSTM networks

  • Duan, Da-You;Wang, Zuo-Cai;Sun, Xiao-Tong;Xin, Yu
    • Smart Structures and Systems
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    • 제29권4호
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    • pp.599-616
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    • 2022
  • Bridge displacement contains vital information for bridge condition and performance. Due to the limits of direct displacement measurement methods, the indirect displacement reconstruction methods based on the strain or acceleration data are also developed in engineering applications. There are still some deficiencies of the displacement reconstruction methods based on strain or acceleration in practice. This paper proposed a novel method based on long short-term memory (LSTM) networks to reconstruct the bridge dynamic displacements with the strain and acceleration data source. The LSTM networks with three hidden layers are utilized to map the relationships between the measured responses and the bridge displacement. To achieve the data fusion, the input strain and acceleration data need to be preprocessed by normalization and then the corresponding dynamic displacement responses can be reconstructed by the LSTM networks. In the numerical simulation, the errors of the displacement reconstruction are below 9% for different load cases, and the proposed method is robust when the input strain and acceleration data contains additive noise. The hyper-parameter effect is analyzed and the displacement reconstruction accuracies of different machine learning methods are compared. For experimental verification, the errors are below 6% for the simply supported beam and continuous beam cases. Both the numerical and experimental results indicate that the proposed data fusion method can accurately reconstruct the displacement.

기록치 오차와 유역모형의 검정(I) - 기록치 내의 측정 오차 분석 - (Errors in Recorded Information and Calibration of a Catchment Modelling System(I) - Analysis of Measurement Errors in Recorded Information -)

  • Kyung Sook Choi;James E. Ball
    • 한국농공학회지
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    • 제45권5호
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    • pp.110-116
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    • 2003
  • A catchment modelling system is the summation of the numerous hydrologic, hydraulic and other process models necessary to simulate the response of a catchment to a storm event. Differences between the recorded catchment response and that predicted by a catchment modelling system can arise from structural errors within the catchment modelling system, evaluation errors in the control parameters, or measurement errors in the recorded data being used to assess the reliability of the evaluation of the control parameters. Presented herein is an investigation of the potential measurement errors within the recorded information, which was considered to occur from instrument error in the ultra sonic flow monitor. This investigation was undertaken using three available rating curves at the Musgrave Avenue Stormwater System in Centennial Park, Sydney, developed by Abustan (1997), Water Board (1994), and using Manning's equation.