ANN-based estimation of MEMS diaphragm response: An application for three leaf clover diaphragm based Fabry-Perot interferometer

In this study, an artificial neural network (ANN) based model is developed for MEMS diaphragm analysis, which does not require difficult and time-consuming FEM processes. ANN-based estimator is generated for static pressure response (d) and dynamic pressure response (f) analysis of TLC (three leaf clover) diaphragms for Fabry-Perot interferometers as an example. TLC is one of the unsealed MEMS design diaphragms formed by three leaves of equal angles. The diaphragms used to train ANNs are designed with SOLIDWORKS and analyzed with ANSYS. A total of 1680 TLC diaphragms are simulated with eight diaphragm parameters (3 for SiO2 material, 4 for geometry, and 1 for pressure) to create a data pool for ANN's training, validation, and testing processes. 80% of the data is used for training, 15% for validation, and the remaining for testing. Only four geometric parameters are used as input in the ANN estimator, and the material parameters are added to the model with an analytical multiplier. Thus, network models that estimate d and f values for all kinds of diaphragm materials are proposed, with a material-independently trained ANN structure. The performance of the ANN model is compared with the empirical equation suggested in the literature, and its superiority is demonstrated. In addition, the d and f parameters of TLC diaphragms designed with five different materials (Si, In2Se3, Ag, EPDM, Graphene) are estimated to be very close to the real ones. By using the proposed method, analyses of TLC diaphragms are quickly performed without the need for time-consuming and costly design and analysis programs. © 2022 Elsevier Lt

THE EFFECT OF MESA DIMENSIONS ON MEMS DIAPHRAGMS FOR FABRY-PEROT INTERFEROMETER-BASED FIBER OPTIC SENSORS

In this study, the effects of mesa dimensions on sensor response in diaphragm-based FabryPerot fiber optic sensors (FOSs) were investigated in detail. Mesa diaphragms, also called centerembossed diaphragms, have been discussed sufficiently in the literature, but the effect of mesa thickness on sensor performance has not been discussed in detail. Moreover, there is no precise analytical solution for such diaphragms. For this reason, diaphragms with different thicknesses and radii were selected, and the deflection and frequency responses of the diaphragm according to the applied acoustic pressure were analyzed using the ANSYS software, depending on whether the mesa is thinner or thicker than the diaphragm. If the thickness of the mesa is smaller than the thickness of the diaphragm, the center deflection changes drastically. However, if the thickness of the mesa is two times greater than the thickness of the diaphragm, there is no significant change in the deflection results. Similarly, if the mesa thickness is thinner than the diaphragm, the sensor’s frequency response changes drastically with increasing mesa radius. In cases where the mesa thickness is larger than the diaphragm thickness, the frequency response changes less. According to the results, mesa dimensions should be considered when designing a mesa diaphragm-based Fabry-Perot FOS

Fiber Optik Fabry-Perot Akustik Sensörler için Yeni Bir Diyafram Malzemesi Olarak 2D GaSe Benzetimi

Algılanacak akustik/basınç sinyalinin şiddet ve frekans değerine duyarlı uçlar üretmek diyafram tasarımının doğru yapılmasıyla sağlanır. Kullanılan diyafram malzemesinin hem geometrik boyutları hem de yapısal özellikleri (yoğunluk, Young modülü, Poisson oranı gibi) sensör performansını etkileyen unsurlardır. Bu durumdan ötürü literatürde farklı tipte diyafram malzemeleri araştırılmaktadır. Bu çalışmada diyafram tabanlı fiber optik Fabry-Perot (FP) akustik sensörlerde kilit rol oynayan diyafram performansı üzerine hesaplamalar verilmiştir. Hesaplamalarda diyafram olarak grafen benzeri iki boyutlu (2D) Galyum Selenit (GaSe) kullanılmıştır. 2D malzemeler sınıfına ait GaSe malzemesi fiber optik FP akustik sensör uç tasarımında diyafram olarak ilk defa hesaplanmış ve benzetim yoluyla sensör ucunun performansı teorik olarak elde edilmiştir. Teorik hesaplamalar ve benzetimler neticesinde 2D GaSe malzemesi fiber optik FP akustik sensör uç üretiminde diyafram olarak kullanılabileceği öngörülmüştür. Oluşturulan uçların frekans cevapları ve akustik basınca duyarlılığı teorik olarak hesaplanmış ve literatürde kullanılan diğer geleneksel malzemelerden elde edilen sonuçlar ile karşılaştırılarak verilmiştir. Sensör görünürlüğü ve frekansı açısından GaSe malzemesinin kullanım alanına göre alternatifler sunduğu görülmüştür

Analytical analysis and experimental validation of optical power estimation in V-grooved polymer optical fibers

In this study, analytical and experimental research of V-grooved polymer optical fibers (POFs)' optical power loss characteristics is carried out. A simple mathematical model that can determine the optical output power and loss in the V-grooved structure depending on the groove angle and depth has been developed using geometric optic approaches. This model is used to analyze the effects of groove parameters and fiber diameter on optical output power in detail. Then, a low-cost and efficient groove fabrication process is performed, and V-grooves with 45 degrees half-angle and 200 mu m groove depth are created on POFs with diameters of 1 mm, 2 mm, and 3 mm to be used in the experiment. When the effect of groove numbers ranging from 5 to 25 on the optical output power is examined, the behavior obtained from the experimental results is compatible with the analytical results. Output power can be estimated with greater than 95% accuracy for V-groove POF structures, optimizing the ratio of groove depth to fiber core radius for a specific groove angle

Fiber Optic Sensor Design and Prototyping for Humidity Detection in Biogas Reactors

In biogas reactors, it is vital to monitor the condensation of water vapor with increasing humidity. The use of fiber optic-based sensors that allow this control to be done online quickly and reliably facilitates the process. In this study, a fiber-optic water vapor and condensation sensor was designed and implemented for biogas reactors. It enables the detection of water due to water vapor and condensation that will increase humidity level based on the combination of fiber reflection losses and longitudinal alignment losses. By creating a very low-cost sensor mechanism that can react quickly and is not affected by environmental variables other than the parameter to be detected, the increasing water vapor and the initial moment of the condensation can be detected with high precision and speed

Fiber optic tactile sensor for surface roughness recognition by machine learning algorithms

In this study, a sensor tip with a metallic hemispherical nozzle tip (MHNT) design based on the Fabry-Perot interferometer was developed for surface roughness recognition (SRR). Sandpaper samples with ten different arithmetical mean deviations of the surface (Sa) values were used as surfaces to be recognized. The feature vectors were found by applying the discrete wavelet transform (DWT) to the analog signals obtained from the sandpaper samples. Machine learning (ML) algorithms K-nearest neighbor (KNN) and support vector machine (SVM) were used for classification. An in-depth recognition process was carried out using the classifiers’ different length criteria and kernel types. In the test process, each category consists of two sub-categories as testing within the training dataset (TWITD) and testing without the training dataset (TWOTD). The experiments were carried out in a controlled manner with the conveyor belt system (CBS) and manual. As a result of the experimental studies, the average recognition rates (Rave) for CBS were found as 84.2% and 81.6% for TWITD and TWOTD, while the Rave for the manual are found as 80% and 77.5% for TWITD and TWOTD, respectivel

Milimetre Altı Ölçümler İçin Fiber Optik Yer Değiştirme Sensörü

Bu çalışma milimetre altı yer değiştirmenin algılanması için birden fazla fiber kayıp mekanizmasının aynı anda değerlendirilip sensör parametrelerinin elde edilmesine dayanmaktadır. Bu kapsamda fiber hizalama kayıplarından olan boyuna yanlış hizalama kayıplarına ilaveten Fresnel yansıma kayıplarının da birlikte değerlendirildiği bir sensör sistemi incelenmiştir. Her iki kayıp mekanizmasının etkisi tek bir eşitlik ile ifade edilip sensör sisteminde kullanılacak fiber tiplerinin etkileri araştırılmıştır. Böylelikle plastik optik fiberle oluşturulacak yer değiştirme sensörünün milimetre altı ölçüm yapabilmesinin incelenen fiber parametrelerinde en uygun değerler belirlenmiştir. Hesaplamalar sonucunda birbirinden farklı çap değerlerine sahip olan fiber tipleri için 1 mm’nin altında yer değiştirme ölçümlerinde kullanılacak en uygun fiber tipinin mümkün olan en düşük çapa sahip olması sonucuna ulaşılmıştır. Fiberlerin tipik çap değerleri dikkate alındığında bu durum için en uygun adayın 980/1000 (öz/yelek) µm çapa sahip olan fiber olduğu belirlenmiştir. Bu fiberin hassasiyetlik derecesi giriş fiberine uygulanan güç 100 µW olduğunda 32,05 µW/mm olarak bulunmuştur. Bu sonuçlar 1960 µm ve 2944 µm öz çapına sahip olan diğer fiberler için sırasıyla, 16,02 µm/mm ve 10,67 µm/mm olarak bulunmuştur.</p

U-Shaped POF Sensor for Ethanol/Methanol Determination

In this study, U-shaped fiber optic sensor tips sensitive to refractive index(RI) change were produced, and its performance analyses were carried out. Threesensor tips were used to measure ethanol/methanol-water mixtures inconcentrations from 0% to 16.66%. The ethanol sensor tip was able to detect the RIchange of 4×10-4 RIU. Its maximum sensitivity is 7.71 mV/RIU, and its linearity is0.9985. The methanol sensor tip was able to detect the RI change of 1×10-4 RIU. Itsmaximum sensitivity is 28.49 mV/RIU, and its linearity is 0.9969. Each sensor tipsdetermine the change of 1.41% concentration in the mixtures. Moreover, the resultsshow that it can provide high precision in the measurement of ethanol/methanolwater mixtures and achieve satisfying stability and repeatability</p

Analyzing the effect of dynamic properties of materials and operating medium on sensor parameters to increase the performance of diaphragm-based static/dynamic pressure sensors

© 2021, The Author(s), under exclusive licence to Springer Science+Business Media, LLC part of Springer Nature.In the design of a high-performance diaphragm-based static/dynamic pressure sensor (DB-S/DPS), researchers have mostly carried out studies on static deflection and frequency analysis without including diaphragm vibration damping and the effect of the operating medium (OM). However, diaphragms and OM usually contain dynamic processes where vibration damping occurs with constantly changing frequency parameters. Therefore, to design a sensor that will work in such an OM, the effect of the dynamic pressure performance of the diaphragm materials on the sensor parameters (sensitivity, bandwidth, linearity) becomes even more important. In this study, for the first time in the literature, the effect of many different parameters on sensor parameters at the same time was analyzed by theoretically examining the dynamic deflection and static deflection expressions that the researchers did not consider in the pressure sensor design. Also, for the first time in the literature, the analysis of the dynamic parameters of many diaphragm materials and sensor operating media was carried out with this study. In order to determine the effect of the dynamic pressure performance of the diaphragms on sensor parameters in high-performance DB-S/DPS design, multiple parameter implementation (MPI) was carried out with MATLAB software. MPI has been realized considering various diaphragm materials, alternative operating media, and all the dynamic parameters (the damping ratio of the medium, added virtual mass incremental factor). In the work, metallic (Al, Au), polymer (cellulose triacetate), semiconductor (Si), glass derivative (SiO2), and two-dimensional (graphene) materials which are frequently reported in the literature were chosen as the diaphragm. The effects of these selected materials and OMs (air, water, mineral oil) on sensor parameters were examined in detail. To the best of our knowledge, there is no comprehensive study in the literature involving such dynamic pressure parameters. With this valuable research, considering the forced oscillations and damping, valuable and interesting results are presented that can guide DB-S/DPS designers

BÜKÜLMÜŞ POLİMER OPTİK FİBER SENSÖR İLE SU İÇERİNDEKİ ALKOL KONSANTRASYONU VE TÜR TAYİNİ

Inthis study, U-shaped bending fiber optic sensor tips based on bending lossesand sensitivity to the medium’s refractive index changes were designed andproduced. U-1, U-2, and U-3 sensing tips were produced by using bare polymerfibers with three different fiber diameters of 1, 2, and 3 mm, respectively.Since all the fibers have a high numerical aperture value of 0.5, thissituation facilitates the light’s guiding into the fiber easily. Tips’responses during the transition between air and water were considered andobtained sensitivity degrees. Three sensor tips were used to measureethanol-water and methanol-water mixtures. The tip named U-2 was found to bemost suitable for the detection of ethanol concentration. This sensor tip wasable to detect the change in the refractive index of Δn&lt;5×10-4RIU with the linearity of 0,999 in ethanol concentrations. Similarly, the sensor tip named U-3 was the most appropriate tip for thedetection of methanol concentration. This sensor tip was able to detect thedifference in the refractive index of Δn&lt;2×10-4 RIU with thelinearity of 0,997. Both sensor tips were able todetect with high precision, stability, and repeatability up to 15% alcohol concentrationin the mixtures. Besides, the sensors produced very simple, easy, and cheap canbe benefited to recognize alcohol type in water.&nbsp;</p