• Title, Summary, Keyword: Displacement

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A Basic Study of Displacement Measurement of Magnetic Bearing System Using Hall Effect Sensor (자기베어링 시스템에서의 변위측정을 위한 홀 효과 센서의 기초 연구)

  • Yang, J.H.;Jeong, G.G.;Jeong, H.H.;Son, S.K.
    • Journal of the Korea Society For Power System Engineering
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    • v.11 no.2
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    • pp.72-76
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    • 2007
  • Since the magnetic bearing system has unstability inherently it is necessary to measure the displacement for stable operation. Normally the displacement measurement is implemented by using sensors. The sensor for the displacement measurement is selected by precision, installation space, effect of magnetic field and response speed. And the cost of displacement measurement sensor also is considered. At the cost the hall effect sensor has a large advantage comparing with the others. Therefore this study concern about the basis experimental test for the displacement measurement of the magnetic bearing system that uses the hall effect sensor coupled with a tiny permanent magnet. The experimental results confirm the validity and practicability for this displacement measurement sensor.

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Disturbance Observer-Based Hybrid Control of Displacement and Force in a Medical Tele-Analyzer

  • Suebsomran Anan;Parnichkun Manukid
    • International Journal of Control, Automation, and Systems
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    • v.3 no.1
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    • pp.70-78
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    • 2005
  • This paper presents hybrid control of displacement and force in a Medical Tele-Analyzer by disturbance observer-based controller which is robust to internal and external disturbances; model uncertainty, load, and friction for instances. The developed Medical Tele-Analyzer consists of 2 subsystems; doctor-side subsystem and patient-side subsystem. In the doctor side subsystem, an array of displacement sensor is equipped to detect movement of doctor's hand and fingers. The detected information is transmitted to the patient side to be used in medical analysis. On the other hand, the patient-side subsystem consists of an array of displacement actuators, which is used to follow displacement of doctor's hand and fingers. An array of force sensors is used to detect forces between patient and the equipment. Since displacement control in patient side is coupled with force control in doctor side and vice-versa, design of the controller has to take into account this coupling. Not only using in medical tele-analysis, the proposed system can also be used in any tele-displacement-force controls of industrial processes.

An application of large displacement limit analysis to frame structures

  • Challamel, Noel
    • Structural Engineering and Mechanics
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    • v.33 no.2
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    • pp.159-177
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    • 2009
  • The aim of this paper is to give a rigorous framework for the interpretation of limit analysis results including large displacements. The presentation is oriented towards unidimensional media (beams) but two-dimensional (plates) or three-dimensional media are also concerned. A single-degree-of-freedom system is first considered: it shows the basic phenomena of large displacement limit analysis or second-order limit analysis. The results are compared to those of a continuous system and the differences between both systems are discussed. Theoretical results are obtained using the kinematical approach of limit analysis. An admissible load-displacement plane is then defined, according to the yield design theory. The methodology used is applied to frame structures. The presented results are nevertheless different from those already published in the literature, as the virtual displacement field can be distinguished from the displacement field at collapse. The simplicity of large displacement limit analysis makes it attractive for practical engineering applications. The load-displacement upper bound can be used for instance in the optimal design of steel frames in seismic areas.

Residual displacement estimation of simple structures considering soil structure interaction

  • Aydemir, Muberra Eser;Aydemir, Cem
    • Earthquakes and Structures
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    • v.16 no.1
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    • pp.69-82
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    • 2019
  • As the residual displacement and/or drift demands are commonly used for seismic assessment of buildings, the estimation of these values play a very critical role through earthquake design philosophy. The residual displacement estimation of fixed base structures has been the topic of numerous researches up to now, but the effect of soil flexibility is almost always omitted. In this study, residual displacement demands are investigated for SDOF systems with period range of 0.1-3.0 s for near-field and far-field ground motions for both fixed and interacting cases. The elastoplastic model is used to represent non-degrading structures. Based on time history analyses, a new simple yet effective equation is proposed for residual displacement demand of any system whether fixed base or interacting as a function of structural period, lateral strength ratio and spectral displacement.

Progressive fracture analysis of concrete using finite elements with embedded displacement discontinuity

  • Song, Ha-Won;Shim, Byul;Woo, Seung-Min;Koo, Ja-Choon
    • Structural Engineering and Mechanics
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    • v.11 no.6
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    • pp.591-604
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    • 2001
  • In this paper, a finite element with embedded displacement discontinuity which eliminates the need for remeshing of elements in the discrete crack approach is applied for the progressive fracture analysis of concrete structures. A finite element formulation is implemented with the extension of the principle of virtual work to a continuum which contains internal displacement discontinuity. By introducing a discontinuous displacement shape function into the finite element formulation, the displacement discontinuity is obtained within an element. By applying either a nonlinear or an idealized linear softening curve representing the fracture process zone (FPZ) of concrete as a constitutive equation to the displacement discontinuity, progressive fracture analysis of concrete structures is performed. In this analysis, localized progressive fracture simultaneous with crack closure in concrete structures under mixed mode loading is simulated by adopting the unloading path in the softening curve. Several examples demonstrate the capability of the analytical technique for the progressive fracture analysis of concrete structures.

Approximate seismic displacement capacity of piles in marine oil terminals

  • Goel, Rakesh K.
    • Earthquakes and Structures
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    • v.1 no.1
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    • pp.129-146
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    • 2010
  • This paper proposes an approximate procedure to estimate seismic displacement capacity - defined as yield displacement times the displacement ductility - of piles in marine oil terminals. It is shown that the displacement ductility of piles is relatively insensitive to most of the pile parameters within ranges typically applicable to most piles in marine oil terminals. Based on parametric studies, lower bound values of the displacement ductility of two types of piles commonly used in marine oil terminals - reinforced-concrete and hollow-steel - with either pin connection or full-moment-connection to the deck for two seismic design levels - Level 1 or Level 2 - and for two locations of the hinging in the pile - near the deck or below the ground - are proposed. The lower bound values of the displacement ductility are determined such that the material strain limits specified in the Marine Oil Terminal Engineering and Maintenance Standard (MOTEMS) are satisfied at each design level. The simplified procedure presented in this paper is intended to be used for preliminary design of piles or as a check on the results from the detailed nonlinear static pushover analysis procedure, with material strain control, specified in the MOTEMS.

Clinical Studies on Abomasal Displacement of Dairy Cows (유우제사위전위증에 관한 임상적 조사연구)

  • Cheong Chang-Kook;Jo Choong-Ho;Sung Jai-ki;Choi Hee-In;Hwang Woo-Suk;Nam Tchi-Chou
    • Journal of Veterinary Clinics
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    • v.1 no.1
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    • pp.11-23
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    • 1984
  • Epizootiolosical factors of 166 cows with abomasal displacement were studied and in 21 out of 166 cows, the functions of liver and kidney were also tested. 1. Incidence of abomasal displacement was perdominant in small sized dairy herd less than 15 cows, using area of paddock below 165㎡. 2. Out of 166 cows with abomasal displacement, 116 cows (70%) were found left sided displacement and 50 cows (30%) were right. 3. Generally, one to two weeks were taken before treatment of veterinarian following onset of sign of the diseases. Therefore many cases were found to be severe in their illness. 4, Incidence rate of abomasal displacement was predominant in summer season (June, July and Au-gust). However, occurence of the disease was continuous throughout the year. About 80 percent of abomasal displacement was distributed from first to third purturition. 5. High milk production and feeding with high concentrates and low roughage showed a tendendy to occurs the disease. 6. Approximately 75% of abomasal displacement was distributed within 1 month pre and post partum. 7. Cows with abomasal displacement consumed little concetrates and 75% of cows with abomasal displacement passed abnormal fecal material. 8. Sixty six out of 166 cows with abomsal displacement were coincident with diseases such as retained placenta, metritis, traumatic reticulo-peritonitis and mastitis. 9. In many cass of abomasal displacement, abomasum was extended with gas. 10. Activities of AST ana LDH showed the trends to reduce after surgical intervention comparing with pre-surgery. Bilirubin concentration markedly decreased after surgical treatment comparing with pre-surgery. 11. The concentration of BUN and creatinine moderatly decreased after surgery compared with pre-surgery.

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A CLINICAL STUDY OF TEMPOROMANDIBULAR JOINT DISORDERS BY USING ARTHROGRAPHY (측두하악관절조영술을 이용한 측두하악관절장애의 임상적 연구)

  • Lee Seung-Hyun;Hwang Eui-Hwan;Lee Sang-Rae
    • The Journal of Korean Academy of Maxillofacial Radiology
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    • v.28 no.1
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    • pp.155-169
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    • 1998
  • The purpose of this study was to prove the relationship between arthrographic and clinical features in temporomandibular joint disorders. In order to carry out this study, ninety-eight arthrographic examinations of temporomandibular joints were performed on eighty-two patients who had the temporomandibular joint disorders. As the arthrographic examination, the cases were classified in three groups, disk displacement with reduction, disk displacement without reduction, within normal limit. After this, the cases were clinically examined, and the results were compared and analyzed in each other group. The obtained results were as follows; 1. As the classification by arthrographic examination, three groups (disc displacement with reduction, disc displacement without reduction, within normal limit) were 41 %, 54%, 5% of total cases in this study, respectively. 2. The third decade(65%) was most frequent in this study. The average age of each group (disc displacement with reduction, disc displacement without reduction, within normal limit) was 24, 28, 21, and disc displacement without reduction group was higher than any other group. 3. In the chief complaint, pain was the most frequent in all three groups. Joint sound was also frequent in disc displacement with reduction group, but in disc displacement without reduction group, limitation of mouth opening was more frequent. 4. Of the various pain, the movement pain was most frequent ( 61 %) in this study. In joint sound, click(63%) was the most frequent in disc displacement with reduction group, but sound history(42%) and no sound (31 %) were more frequent in disc displacement without reduction group. 5. The average maximum opening of each group (disc displacement with reduction, disc displacement without reduction, within normal limit) was 44mm, 32.9mm, 44mm, and disc displacement without reduction group was less than any other group. 6. The masticatory disturbance of each group (disc displacement with reduction, disc displacement without reduction, within normal limit) was 53%, 79%, 40%, and the trauma history of each group was 50%, 40%,60%.

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CHANCE OF JOINT SPACE ACCORDING TO ANTERIOR DISC DISPLACEMENT OF TMJ (악관절원판의 전방변위에 따른 관절간극의 변화)

  • Bae Jung-Soo;Kim Joon-Bae;Kim Hyung-Soon
    • The Journal of Korean Academy of Prosthodontics
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    • v.39 no.4
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    • pp.410-416
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    • 2001
  • Objective: Disc displacement may affect the joint space narrowing between condylar head and glenoid fossa. This study was designed to evaluate the correlation between the joint space change and the severity of anterior disc displacement. Materials and Methods: Two hundreds temporomandibular joints MR images of TMD patients(170 joints) and asymptomatic volunteers(30 joints) were evaluated for this purpose. Anterior disc displacement was divided into 3 stages(normal, little to mild, and moderate to severe displacement) based on sagittal images, then joint spaces were measured at medial, central and lateral parts of condyle head on coronal MR images, respectively The joint spaces of 3 groups divided according to the severity of anterior disc displacement were compared. Results: The reduction of joint space was related to the severity of the anterior disc displacement at lateral, medial side and especially at center Conclusion: The temporomandibular joint space was affected by the severity of the anterior disc displacement.

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Incremental Displacement Estimation Algorithm for Real-Time Structural Displacement Monitoring (실시간 구조물 변위 모니터링을 위한 증분형 변위 측정 알고리즘)

  • Jeon, Hae-Min;Shin, Jae-Uk;Myeong, Wan-Cheol;Myung, Hyun
    • Journal of Institute of Control, Robotics and Systems
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    • v.18 no.6
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    • pp.579-583
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    • 2012
  • The purpose of this paper is to suggest IDE (Incremental Displacement Estimation) algorithm for the previously proposed visually servoed paired structured light system. The system is composed of two sides facing with each other, each with one or two lasers with a 2-DOF manipulator, a camera, and a screen. The 6-DOF displacement between two sides can be estimated by calculating the positions of the projected laser beams and rotation angles of the manipulators. In the previous study, Newton-Raphson or EKF (Extended Kalman Filter) has been used as an estimation algorithm. Although the various experimental tests have validated the performance of the system and estimation algorithms, the computation time is relatively long since aforementioned algorithms are iterative methods. Therefore, in this paper, a non-iterative incremental displacement estimation algorithm which updates the previously estimated displacement with a difference of the previous and the current observed data is introduced. To verify the performance of the algorithm, experimental tests have been performed. The results show that the proposed non-iterative algorithm estimates the displacement with the same level of accuracy compared to the EKF with multiple iterations with significantly less computation time.