We present a passive vibration compensation approach in scanning white-light interferometry (SWLI). A pointwise distance measuring interferometer (DMI) obtains fast temporal distance changes during the white-light depth-scan of an aerial-measuring Michelson white-light interferometer for topography measurement. Both interferometers share a part of the optical path so that the measurement spot of the DMI is within the field of view of SWLI. With the real positions of the interferometer with respect to the measuring object during the depth scan known from DMI measurements, we can compensate for the influence of unintentional distance changes caused by environmental vibrations or scanner nonlinearities. By reordering of the captured image frames and improved correlogram interpolation, we are able to reconstruct correct signals from completely distorted (and unusable) SWLI signals. Although the basic idea of the system already has been published, we improved the signal reconstruction technique so that the specimen's topography measurement can be obtained with the same accuracy as without any vibrations or scan distortions influence. In addition, we demonstrate the feasibility of the approach by different practical measurements with and without vibrations.
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http://dx.doi.org/10.1364/AO.55.006172 | DOI Listing |
Materials (Basel)
January 2025
Department of Civil Engineering, University of Texas Rio Grande Valley, Edinburg, TX 78539, USA.
This paper focuses on the theoretical and analytical modeling of a novel seismic isolator termed the Passive Friction Mechanical Metamaterial Seismic Isolator (PFSMBI) system, which is designed for seismic hazard mitigation in multi-story buildings. The PFSMBI system consists of a lattice structure composed of a series of identical small cells interconnected by layers made of viscoelastic materials. The main function of the lattice is to shift the fundamental natural frequency of the building away from the dominant frequency of earthquake excitations by creating low-frequency bandgaps (FBGs) below 20 Hz.
View Article and Find Full Text PDFJ Funct Morphol Kinesiol
January 2025
Institute of Human Movement Science, Sport and Health, University of Graz, 8010 Graz, Austria.
: Increasing exercise intensity and performance output with superimposed vibration gains interest, especially in high-performance training. However, the additional benefit of vibration in passive stretching exercises and its mechanisms remain unclarified. : Passive stretching with (ST+V) and without (ST) vibration (20 Hz) was performed in male Olympic youth skiing athletes ( = 8, age: 17.
View Article and Find Full Text PDFPLoS One
January 2025
Faculty of Mechanical Engineering, Thuyloi University, Hanoi, Vietnam.
Road surface roughness is the cause of vehicle vibration, which is considered a system disturbance. Previous studies on suspension system control often ignore the influence of disturbances while designing the controller, leading to system performance degradation under severe vibration conditions. In this work, we propose a control method to improve active suspension performance that reduces vehicle vibration by eliminating the influence of road disturbances.
View Article and Find Full Text PDFSensors (Basel)
December 2024
Institute of Railway Research, University of Huddersfield, Huddersfield HD1 3DH, UK.
Conventional floating bridge systems used during emergency repairs, such as during wartime or after natural disasters, typically rely on passive rubber bearings or semi-active control systems. These methods often limit traffic speed, stability, and safety under dynamic conditions, including varying vehicle loads and fluctuating water levels. To address these challenges, this study proposes a novel Hydraulic Self-Adaptive Bearing System (HABS).
View Article and Find Full Text PDFSpace payloads in orbit are vulnerable to small vibrations from satellite platforms, which can degrade their performance. Traditional methods typically involve installing a passive vibration isolation system between the platform and the payload. However, such systems are usually effective only for high-frequency, large-amplitude vibrations and perform poorly in isolating low-frequency vibrations and resonances below 10 Hz.
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