• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.17 no.1 s.118
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• pp.72-79
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• 2007

As environmental vibration requirements on precision equipment become more stringent, use of pneumatic isolators has become more popular and their performance is subsequently required to be further improved. Dynamic performance of passive pneumatic isolators is related to various design parameters in a complicated manner and, hence, is very limited especially in low frequency range by volume of chambers. In this study, an active control technique, so called time delay control which is considered to be adequate for a low frequency or nonlinear system, is applied to a single chamber pneumatic isolator. The procedure of applying the tine delay control law to the pneumatic isolator is presented and its effectiveness in enhancement of transmissibility performance is shown based on simulation and experiment. Comparison between passive and active pneumatic isolators is also presented.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.23 no.1
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• pp.17-24
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• 2013

The process of producing high precision and light weight product is always exposed to impact load or shock. Because of this, isolator device is required. To measure the response of the isolator, accelerometer is practically used. However, the measured response of the accelerometer is different to the response of the isolator. To predict the response of the accelerometer and the isolator, 2-DOF damped system with an input shock is modeled using numerical analysis. 1-DOF damped system with a base excitation is also used to predict the response of the isolator. The mass ratio, damping ratio, and natural frequency ratio are then varied. The predicted responses from the two modeling approaches are compared and large errors are found.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.1
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• pp.25-31
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• 2009

The anti-vibration tables that use air suspensions as dampers have been widely used due to their high anti-vibration performance in wide frequency band. However, they face a problem of easily accelerating the vibration when triggered by external force because their air suspensions have low rigidity and dampness. In response, there has been a study on active/semi-active dampers that use only the passive components like air suspensions to complement the passive-control format. Thus, we have dynamically analyzed the active/semi-active control of such passive anti-vibration tables. To demonstrate the anti-vibration table's control system, we have also constructed a kinetic model based on the physical characteristics of an anti-vibration table with 6 degrees of freedom and verified its applicability through analysis and experiments.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.16 no.11 s.116
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• pp.1100-1107
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• 2006

As environmental vibration requirements on precision equipment become more stringent, use of pneumatic isolators has become more popular and their performance is subsequently required to be further improved. Performance of passive pneumatic isolators is related to various design parameters in a complicated manner and, hence, is very limited especially in low frequency range by chamber volume. In this study, transmissibility behavior of the pneumatic isolators depending on frequency and dynamic amplitude are presented. Then, an active control technique, time delay control, which is adequate for a low frequency nonlinear system, is applied. A procedure of applying the time delay control law to a pneumatic isolator is presented and it's effectiveness in the transmissibility performance is shown. Comparison between passive and active pneumatic isolators is made based on simulation.

• 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.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2006.05a
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• pp.837-843
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• 2006

As environmental vibration requirements on precision equipment become more stringent, use of pneumatic isolators has become more popular and their performance is subsequently required to be further improved. Performance of passive pneumatic isolators is related to various design parameters in a complicated manner and, hence, is very limited especially in low frequency range by chamber volume. In this study, transmissibility behavior of the pneumatic isolators depending on frequency and dynamic amplitude are presented. Then, an active control technique, time delay control, which is adequate for a low frequency nonlinear system, is applied. A procedure of applying the time delay control law to a pneumatic isolator is presented and it's effectiveness in the transmissibility performance is shown. Comparison between passive and active pneumatic isolators is made based on simulation.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2011.04a
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• pp.560-561
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• 2011

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2010.10a
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• pp.114-115
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• 2010

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2012.05a
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• pp.619-620
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• 2012

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2012.10a
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• pp.350-351
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• 2012