• Title/Summary/Keyword: Vibration Isolator

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Design Parameter Study on the Isolation Performance of the HSLDS Magnetic Vibration Isolator (HSLDS 마그네틱 진동절연체의 절연성능에 대한 설계 파라미터 분석)

  • Shin, Ki-Hong
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2009.10a
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    • pp.473-477
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    • 2009
  • In general, the softer the stiffness of a linear vibration isolator the better the performance of isolation can be achieved. However, the stiffness of the isolator cannot be made too soft because it needs a sufficient stiffness to hold the load. This is the most critical limitation of a linear vibration isolator. Recently, a HSLDS (High-Static-Low-Dynamic-Stiffness) magnetic vibration isolator was proposed to overcome this fundamental limitation. The suggested isolator utilizes two pairs of attracting magnets that that introduces negative stiffness. Previously, this new type of vibration isolator was merely introduced and showed a possibility of practical use. In this paper, detailed dynamics of the HSLDS magnetic isolator are studied using computer simulations. Then, the isolation performance is examined for various design parameters to aid the practical use.

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Design Parameter Study on the Isolation Performance of the HSLDS Magnetic Vibration Isolator (HSLDS 마그네틱 진동절연체의 절연성능에 대한 설계 파라미터 분석)

  • Shin, Ki-Hong
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.20 no.1
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    • pp.92-97
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    • 2010
  • In general, the softer the stiffness of a linear vibration isolator the better the performance of isolation can be achieved. However, the stiffness of the isolator cannot be made too soft because it needs a sufficient stiffness to hold the load. This is the most critical limitation of a linear vibration isolator. Recently, a HSLDS(high-static-low-dynamic-stiffness) magnetic vibration isolator was proposed to overcome this fundamental limitation. The suggested isolator utilizes two pairs of attracting magnets that introduces negative stiffness. Previously, this new type of vibration isolator was merely introduced and showed a possibility of practical use. In this paper, detailed dynamics of the HSLDS magnetic isolator are studied using computer simulations. Then, the isolation performance is examined for various design parameters to aid the practical use.

Using Numerical Solutions of the Vibration Measurement Accelerometers attached Vibration Isolator (수치 해법을 이용하여 제진대에 부착된 가속도 센서의 진동 측정)

  • Shin, Dong-Ho;Lee, Jung-Woo;Lee, Jong-Won;Oh, Jae-Eung;Lee, Jung-Youn
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2012.04a
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    • pp.875-880
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    • 2012
  • According to the fixation detailed drawing and lightweight anger tendency of the product the vibration control of precision equipments is essential and establishes under the equipments. so It is important to know vibration characteristics of vibration isolator. For this reason the accelerometer attaches in vibration isolator and measures an acceleration response. The acceleration response which is measured will lead double integral and will be able to predict a displacement of vibration isolator. However, in compliance with the effect of the accelerometer can not be accurately. From this paper, mass, damping ratio and natural frequency of the accelerometers by changing the vibration isolator to predict the acceleration response and the results were compared.

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Micro-vibration Isolation Performance Verification for the Passive Vibration Isolator using SMA Mesh Washer (SMA 메쉬 와셔를 적용한 수동형 진동절연기의 미소진동 절연성능 검증)

  • Kwon, Sung-Cheol;Jeon, Su-Hyeon;Oh, Hyun-Ung
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2014.10a
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    • pp.900-903
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    • 2014
  • Fly-wheel, Gimbal antenna, CMG, Spaceborne cyrocooler generate micro-vibration during their on-orbit operation as well as implementing their own function. To comply with the mission requirement of high resolution observation satellite, additional technical efforts have been required to isolate the micro-vibration derived from such payloads by applying the vibration isolator. In this study, we proposed a passive isolator using SMA mesh washer, which guarantees the structural safety of both micro-vibration disturbance source and itself under harsh launch vibration loads without an additional holding mechanism and the micro-vibration isolation performance on orbit environment. To verify the micro-vibration isolation performance of the proposed vibration isolator, we performed the micro-vibration isolation measurement test using the dedicated micro-vibration measurement device proposed in this study.

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Nonlinear vibration characteristics of a vertical passive zero stiffness isolator (수직방향 수동 영강성 제진기의 비선형 진동 특성)

  • Kim, Kyoung-Hong;Ahn, Hyeong-Joon
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2007.11a
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    • pp.1259-1265
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    • 2007
  • This paper presents nonlinear vibration characteristics of a vertical passive zero stiffness isolator. The passive isolator can achieve zero stiffness through buckling of notched flexure caused by a compressive force. First, a simulation model of the isolator was built based on elastic beam theory. As increasing the compression force, time and frequency responses of the isolator were simulated. In addition, further nonlinear vibration characteristics were investigated through a bifurcation diagram and a Poincare's map, which shows that even chaostic vibration could happen. The simulations show that as the compressive force increases, the stiffness goes close to zero and the nonlinear characteristic becomes stronger to have a great effect on the isolation performance.

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Verification of Launch Vibration and Shock Isolation Performance for Spaceborne Compressor Vibration Isolator with SMA Mesh Washer (형상기억합금 메쉬 와셔를 이용한 우주용 냉각기 진동절연기의 발사 진동 및 충격 저감 성능검증)

  • Lee, Myeong-Jae;Han, Je-Heon;Oh, Hyun-Ung
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.24 no.7
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    • pp.517-524
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    • 2014
  • Micro-vibration induced by on-board equipments such as fly-wheel and cryogenic cooler with mechanical moving parts affects the image quality of high-resolution observation satellite. Micro-vibration isolation system has been widely used for enhancing the pointing performance of observation satellites. In general, the micro-vibration isolation system requires a launch locking mechanism additionally to guarantee the structural safety of mission payloads supported by the isolation system with low stiffness under launch environment. In this study, we propose a passive launch and on-orbit vibration isolation system using shape memory alloy mesh washers for the micro-vibration isolation of spaceborne compressor, which does not require the additional launch locking mechanism. The basic characteristics of the isolator were measured in static and free vibration tests of the isolator, and a simple equivalent model of the isolator was proposed. The effectiveness of the isolator design in a launch environment was demonstrated through sine vibration, random vibration and shock tests.

Derivation of Numerical Equivalent Model of Vibration Isolator using Pseudoelastic SMA Mesh Washer (의탄성 형상기억합금 메쉬 와셔가 적용된 수동형 진동절연기의 수학적 등가모델 도출)

  • Kwon, Sung-Cheol;Jeon, Su-Hyeon;Oh, Hyun-Ung
    • Journal of Aerospace System Engineering
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    • v.8 no.3
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    • pp.6-13
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    • 2014
  • A passive launch and on-orbit vibration isolator using SMA(Shape Memory Alloy) washer for both the structural safety of the micro-vibration source by attenuating the transmitted force under launch loads and the micro-vibration isolation during their on-orbit operation has been proposed, which does not require the additional launch locking mechanism. To measure the characteristics of SMA mesh washer, we performed compressive loading tests with a single SMA mesh washer and a vibration isolator using SMA mesh washer. The numerical equivalent model of vibration isolator using SMA mesh washer composed of two spring and viscous damping elements has been verified that both stiffness and viscous damping varied with respect to compressed deformations. In addition, the effectiveness of launch loads and micro-vibration reduction has been investigated through the dynamic characteristics measurement test of cooler assembly combined with passive vibration isolator.

A Study on the Active Vibration Isolator PID Auto-tuning Using PSO Algorithm (PSO알고리즘을 활용한 능동 제진 시스템 PID 오토 튜닝에 관한 연구)

  • An, Il Kyun;Huh, Heon;Kim, Hyo-Young;Kim, Kihyun
    • Journal of the Semiconductor & Display Technology
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    • v.21 no.4
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    • pp.59-64
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    • 2022
  • Vibration is one of the factors that degrades the performance of equipment and measurement equipment used in high-tech industries such as semiconductors and display. The vibration isolator is classified into passive type and active type. The passive vibration isolator has the weakness of insufficient vibration isolation performance in the low frequency band, so an active vibration control system that can overcome these problems is used recently. In this paper, PID controller is used to control the active vibration isolator. Methods for setting the gain of the PID controller include the Zeigler-Nichols method, the pole placement method. These methods have the disadvantage of requiring a lot of time or knowing the system model accurately. This paper proposes the gain auto tuning method of the active vibration isolator applied with the PSO algorithm, which is an optimization algorithm that is easy to implement and has stable convergence performance with low calculations. It is expected that it will be possible to improve vibration isolation performance and reduce the time required for gain tuning by applying the proposed PSO algorithm to the active vibration isolator.

Performance Evaluation of Hybrid Vibration Isolator using FxLMS algorithm (FxLMS 알고리즘을 적용한 하이브리드 미소진동 절연장치의 절연성능 평가)

  • Lee, Dae-Oen;Park, Geeyong;Han, Jae-Hung
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2014.10a
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    • pp.173-174
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    • 2014
  • Vibration disturbances generated by reaction wheels may cause serious problems in high precision pointing spacecraft missions. Implementation of vibration isolator is a practical solution to meet the high pointing stability requirement placed on precision payloads. In this paper, development of hybrid vibration isolator that combines passive and active component is described. Vibration isolation performance of the developed isolator is evaluated using reaction wheel disturbance model. Hybrid isolation results obtained using FxLMS algorithm show clear improvement compared to the results obtained using only passive means.

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Performance Test of Isolator for Reaction Wheel Micro-Vibration (인공위성 반작용휠 미소진동 감쇠기의 성능 측정)

  • Oh, Shi-Hwan;Seo, Hyun-Ho;Yim, Jo-Ryeong;Rhee, Seung-Wu
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2006.05a
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    • pp.376-379
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    • 2006
  • Reaction Wheel Assembly (RWA) is one of the major disturbance sources that have influence upon the Line of Sight (LOS) of payload. A micro-vibration induced by RWA is propagated through the satellite structure and decrease the LOS stability performance of payload. This effect shall be analyzed through the jitter analysis. If a requirement or specification of payload jitter level is found to be not satisfied according to the jitter analysis campaign, some modification or redesign should be done on the satellite structure or a couple of isolator should be attached on the RWA interface in order to reduce the transmitted vibration level of RWA. The purpose of ???RWA isolator test? is to roughly evaluate the performance of vibration suppression level with a passive RWA isolator made of rubber. For this test, actual RWA is used as a vibration source and a couple of cube-shaped rubber mount designed for satellite is used as a passive isolator. There may be several considerations in order to accommodate RWA isolator to spacecraft such as not only vibration reduction performance but also thermal conduction problem, mechanical size, RWA alignment problem, etc. But in this report the feasibility of RWA isolator is analyzed only in a vibration suppression point of view. As a result, high frequency vibration of RWA above 50Hz is perfectly attenuated with isolators, however, first harmonic components below 50Hz became larger due to the additional low frequency resonance modes of roll, pitch, yaw rigid body motion of RWA+bracket.

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