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Vibrations Analysis of the Fruit-Pedicel System of Coffea arabica var. Castillo Using Time-Frequency and Wavelets Techniques
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SYSNO ASEP 0560545 Document Type J - Journal Article R&D Document Type Journal Article Subsidiary J Článek ve WOS Title Vibrations Analysis of the Fruit-Pedicel System of Coffea arabica var. Castillo Using Time-Frequency and Wavelets Techniques Author(s) Cardona, C. I. (CO)
Tinoco Navaro, Hector Andres (UFM-A) ORCID
Perdomo-Hurtado, L. (CO)
Lopez-Guzman, J. (CO)
Pereira, Daniel A. (BR)Number of authors 5 Article number 9346 Source Title Applied Sciences-Basel. - : MDPI
Roč. 11, č. 19 (2021)Number of pages 17 s. Language eng - English Country CH - Switzerland Keywords vibration analysis ; coffee ; Coffea arabica ; wavelet ; time-frequency analysis Subject RIV JR - Other Machinery OECD category Applied mechanics Method of publishing Open access Institutional support UFM-A - RVO:68081723 UT WOS 000707025300001 EID SCOPUS 85116748741 DOI 10.3390/app11199346 Annotation Colombian coffee production is well-known, and selective manual harvesting plays a vital task in guaranteeing high ripe coffee fruit rates in this process, leading to its known worldwide aroma and flavor. To maintain this quality approach, selective harvesting methods based on mechanical vibrations are a promising alternative for developing technologies that could accomplish the challenging Colombian coffee production context. In this study, a vibrations analysis in coffee fruits at three ripening stages was carried out to evaluate the dynamic behavior at two frequency windows: 10 to 100 Hz and 100 to 1000 Hz. Two groups of fruits previously classified in the CIELab color space were chosen for the vibration test study samples. Time and frequency signals were characterized via FFT (fast Fourier transform), and bump wavelets were determined to obtain the frequency-time magnitude scalograms. The measurements were obtained in three degrees of freedom over the fruits: one for measuring the input force (computed in voltage way) and the other two measured by the velocity. The results revealed frequency ranges with specific resonant peaks between 24 and 45 Hz, and close to 700 Hz, where the ripe fruits presented higher magnitudes in the calculated parameters. FFT of the velocity and scaled mechanical impedance were used to estimate these frequency ranges. This work is an important step to identify a vibrational fingerprint of each Coffea arabica var. Castillo fruit-ripening stage. However, we consider that more experiments should be performed to reconstruct the modal shape in each resonance. In future studies, fatigue analysis could show which are the most effective frequency ranges to detach the ripe fruits from the perspective of a real selective coffee-harvesting scenario./p Workplace Institute of Physics of Materials Contact Yvonna Šrámková, sramkova@ipm.cz, Tel.: 532 290 485 Year of Publishing 2023 Electronic address https://www.mdpi.com/2076-3417/11/19/9346
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