Vibration Control of Scanning Electron Microscopes with Experimental Approaches for Performance Enhancement

Shin, Yun Ho; Moon, Seok‐Jun; Kim, Yong-Ju; Oh, Ki‐Yong

doi:10.3390/s20082277

Cited by 7 publications

(5 citation statements)

References 20 publications

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“…An impact hammer (PCB 086E80, USA, sensitivity: 24.0 mV/g) with a steel tip was used to exert an impulse force to the base. Impulse force in the time domain has a flat amplitude spectrum in the frequency domain; therefore, the entire frequency range was excited with the impulse force [22]. Specifically, the coherence function (Equation ( 24)) during the modal testing showed that coherence was above 0.8 until 160 Hz.…”

Section: Modal Testingmentioning

confidence: 99%

Vibration Isolation of a Surveillance System Equipped in a Drone with Mode Decoupling

et al. 2021

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Vibration isolation with mode decoupling plays a crucial role in the design of an intelligent robotic system. Specifically, a coupled multi-degree-of-freedom (multi-DOF) model accurately predicts responses of system dynamics; hence, it is useful for vibration isolation and control with mode decoupling. This study presents a vibration isolation method with mode decoupling based on system identification, including a coupled multi-DOF model to design intelligent robotic systems. Moreover, the entire procedure is described, including the derivation of the governing equation of the coupled multi-DOF model, estimation of the frequency response function, and parameter estimation using least squares approximation. Furthermore, the suggested methods were applied for a mobile surveillance system suffering from resonances with mode coupling; it made the monitoring performance of the surveillance camera deteriorate. The resonance problem was mitigated by installing vibration isolators, but limited to eliminate the coupling effects of natural frequency deterioration performances of vibration isolation. More seriously, system identification with a simple decoupled model limits the prediction of this phenomenon. Hence, it is difficult to enhance the performance of vibration isolators. In contrast, the presented method can accurately predict the vibration phenomenon and plays a critical role in vibration isolation. Therefore, dynamic characteristics were predicted based on a vibration isolator using the coupled three-DOF model, and a final suggestion is presented here. The experiments demonstrated that the suggested configuration decreased vibration up to 98.3%, 94.0%, and 94.5% in the operational frequency range, i.e., 30–85 Hz, compared to the original surveillance system in the fore-after, side-by-side, and vertical directions, respectively. The analysis suggests that the present method and procedure effectively optimize the vibration isolation performances of a drone containing a surveillance system.

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Section: Modal Testingmentioning

confidence: 99%

Vibration Isolation of a Surveillance System Equipped in a Drone with Mode Decoupling

et al. 2021

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“…Thus, it is necessary to isolate or suppress unexpected vibrations and control them in a reasonable and acceptable range to avoid irreparable loss to the system (Song et al 2022). To address these issues, various vibration isolation systems were developed to suppress the external vibrations and have been widely utilized in various engineering fields including aerospace, precision manufacturing (Wang et al 2013), and scanning microscopy instruments (Shin et al 2020). Referring to the proposed vibration suppression systems, these can be classified into active, semi-active, and passive vibration isolators in terms of the different isolation approaches.…”

Section: Introductionmentioning

confidence: 99%

Modular quasi-zero-stiffness isolator based on compliant constant-force mechanisms for low-frequency vibration isolation

Ding

Xuan

Chen

et al. 2023

Journal of Vibration and Control

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To effectively isolate low-frequency vibrations, we present a rigid–flexible coupling quasi-zero-stiffness (QZS) vibration isolator with high-static-low-dynamic stiffness (HSLDS) characteristics. Specifically, the QZS isolator is realized by the development of a compliant constant-force mechanism, formed by parallelly combining a diamond-shape mechanism and a nonlinear bi-stable beam in parallel. To evaluate performance of the QZS isolator, we derived an analytical force–displacement model and dynamic model based on pseudo-rigid body method and Lagrange’s equations. Then, finite element analysis was performed in Workbench to verify theoretical analysis and identify the optimal design parameters. Furthermore, the dynamic responses of the QZS isolator are established with the harmonic balance method. Finally, the relationships among displacement transmissibility and factors including damping, BSB, payload mass, and material property are discussed. The results have shown that our QZS isolator design can effectively isolate vibrations in low frequency.

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“…The passive PVI usually maintains high vibration isolation performance for vibration disturbances above 10 Hz, but below 10 Hz vibration isolation performance will decrease and resonance will occur near the system's natural frequency [18]. Active PVI keeps the system stable by using precision servo valves to control the gas in and out of the air spring [19][20][21][22]. However, these precision pneumatic servo systems are usually very expensive.…”

Section: Introductionmentioning

confidence: 99%

Research on the Pressure Regulator Effect on a Pneumatic Vibration Isolation System

Shi

Sun

et al. 2022

Chin. J. Mech. Eng.

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The pneumatic vibration isolator (PVI) plays an increasingly important role in precision manufacturing. In this paper, aiming to detect the performance of the pressure regulator in the PVI system, a PVI testing system with a pressure regulator is designed and developed. Firstly, the structure of the pneumatic spring is presented and analyzed, and the nonlinear stiffness is obtained based on the ideal gas model and material mechanics. Then, according to the working principle and continuity equations of ideal airflow, a dynamic model of the PVI system with a pressure regulator is established. Through the simulation analysis, the vibration isolation performance is improved with the efficient and precise pressure regulator. The average values of both the vibration velocity and transmission rate decrease when the vibration is set to 4, 10, 20 and 40 Hz, respectively. The experiments demonstrate the reliability and effectiveness of the pressure regulator. This achievement will become an important basis for future research concerning precision manufacturing.

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Vibration Control of Scanning Electron Microscopes with Experimental Approaches for Performance Enhancement

Cited by 7 publications

References 20 publications

Vibration Isolation of a Surveillance System Equipped in a Drone with Mode Decoupling

Vibration Isolation of a Surveillance System Equipped in a Drone with Mode Decoupling

Modular quasi-zero-stiffness isolator based on compliant constant-force mechanisms for low-frequency vibration isolation

Research on the Pressure Regulator Effect on a Pneumatic Vibration Isolation System

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