scholarly journals Influence of Two-Plane Position and Stress on Intensity-Variation-Based Sensors: Towards Shape Sensing in Polymer Optical Fibers

Sensors ◽  
2021 ◽  
Vol 21 (23) ◽  
pp. 7848
Author(s):  
Vitorino Biazi ◽  
Letícia Avellar ◽  
Anselmo Frizera ◽  
Arnaldo Leal-Junior
Keyword(s):  
Optical Fibers ◽  
Angular Position ◽  
Intensity Variation ◽  
Shape Reconstruction ◽  
Coefficient Of Determination ◽  
Polymer Optical Fiber ◽  
Linear Calibration ◽  
Calibration Curves ◽  
Angular Velocities ◽  
Shape Sensing

Shape reconstruction is growing as an important real-time monitoring strategy for applications that require rigorous control. Polymer optical fiber sensors (POF) have mechanical properties that allow the measurement of large curvatures, making them appropriate for shape sensing. They are also lightweight, compact and chemically stable, meaning they are easy to install and safer in risky environments. This paper presents a sensor system to detect angles in multiple planes using a POF-intensity-variation-based sensor and a procedure to detect the angular position in different planes. Simulations are performed to demonstrate the correlation between the sensor’s mechanical bending response and their optical response. Cyclic flexion experiments are performed at three test frequencies to obtain the sensitivities and the calibration curves of the sensor at different angular positions of the lateral section. A Fast Fourier Transform (FFT) analysis is tested as a method to estimate angular velocities using POF sensors. The experimental results show that the prototype had high repeatability since its sensitivity was similar using different test frequencies at the same lateral section position. The proposed approach proved itself feasible considering that all linear calibration curves presented a coefficient of determination (R2) higher than 0.9.

scholarly journals Performance Analysis of a Lower Limb Multi Joint Angle Sensor Using CYTOP Fiber: Influence of Light Source Wavelength and Angular Velocity Compensation

Sensors ◽  
2020 ◽  
Vol 20 (2) ◽  
pp. 326 ◽  
Author(s):  
Letícia Avellar ◽  
Arnaldo Leal-Junior ◽  
Carlos Marques ◽  
Anselmo Frizera
Keyword(s):  
Angular Velocity ◽  
Light Source ◽  
Intensity Variation ◽  
Maximum Error ◽  
Angular Error ◽  
Polymer Optical Fiber ◽  
Angle Sensor ◽  
Sensor Performance ◽  
Angular Velocities ◽  
Curvature Sensor

This paper presents the analysis of an intensity variation polymer optical fiber (POF)-based angle sensor performance, i.e., sensitivity, hysteresis and determination coefficient ( R 2 ), using cyclic transparent optical polymer (CYTOP) fiber. The analysis consisted of two approaches: influence of different light source central wavelengths (430 nm, 530 nm, 660 nm, 870 nm and 950 nm) and influence of different angular velocities ( 0.70 rad/s, 0.87 rad/s, 1.16 rad/s, 1.75 rad/s and 3.49 rad/s). The first approach aimed to select the source which resulted in the most suitable performance regarding highest sensitivity and linearity while maintaining lowest hysteresis, through the figure of merit. Thereafter, the analysis of different angular velocities was performed to evaluate the influence of velocity in the curvature sensor performance. Then, a discrete angular velocity compensation was proposed in order to reduce the root-mean-square error (RMSE) of responses for different angular velocities. Ten tests for each analysis were performed with angular range of 0 ∘ to 50 ∘ , based on knee and ankle angle range during the gait. The curvature sensor was applied in patterns simulating the knee and ankle during the gait. Results show repeatability and the best sensor performance for λ = 950 nm in the first analysis and show high errors for high angular velocities ( w = 3.49 rad/s) in the second analysis, which presented up to 50 % angular error. The uncompensated RMSE was high for all velocities ( 6.45 ∘ to 12.41 ∘ ), whereas the compensated RMSE decreased up to 74 % ( 1.67 ∘ to 3.62 ∘ ). The compensated responses of application tests showed maximum error of 5.52 ∘ and minimum of 1.06 ∘ , presenting a decrease of mean angular error up to 30 ∘ when compared with uncompensated responses.

scholarly journals Design and analysis of a fiber-optic sensing system for shape reconstruction of a minimally invasive surgical needle

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Aizhan Issatayeva ◽  
Aida Amantayeva ◽  
Wilfried Blanc ◽  
Daniele Tosi ◽  
Carlo Molardi
Keyword(s):  
Performance Analysis ◽  
Minimally Invasive ◽  
Optical Fibers ◽  
Single Mode ◽  
Spectral Shift ◽  
Shape Reconstruction ◽  
Minimally Invasive Surgical ◽  
Working Principle ◽  
Doped Fibers ◽  
Distributed Measurement

AbstractThis paper presents the performance analysis of the system for real-time reconstruction of the shape of the rigid medical needle used for minimally invasive surgeries. The system is based on four optical fibers glued along the needle at 90 degrees from each other to measure distributed strain along the needle from four different sides. The distributed measurement is achieved by the interrogator which detects the light scattered from each section of the fiber connected to it and calculates the strain exposed to the fiber from the spectral shift of that backscattered light. This working principle has a limitation of discriminating only a single fiber because of the overlap of backscattering light from several fibers. In order to use four sensing fibers, the Scattering-Level Multiplexing (SLMux) methodology is applied. SLMux is based on fibers with different scattering levels: standard single-mode fibers (SMF) and MgO-nanoparticles doped fibers with a 35–40 dB higher scattering power. Doped fibers are used as sensing fibers and SMFs are used to spatially separate one sensing fiber from another by selecting appropriate lengths of SMFs. The system with four fibers allows obtaining two pairs of opposite fibers used to reconstruct the needle shape along two perpendicular axes. The performance analysis is conducted by moving the needle tip from 0 to 1 cm by 0.1 cm to four main directions (corresponding to the locations of fibers) and to four intermediate directions (between neighboring fibers). The system accuracy for small bending (0.1–0.5 cm) is 90$$\%$$ % and for large bending (0.6–1 cm) is approximately 92$$\%$$ % .

Electrospray Mass Spectrometry as a Technique for Elemental Analysis: Quantitative Aspects

1994 ◽  
Vol 48 (6) ◽  
pp. 649-654 ◽  
Author(s):  
George R. Agnes ◽  
Gary Horlick
Keyword(s):  
Mass Spectrometry ◽  
Electrospray Mass Spectrometry ◽  
Dynamic Range ◽  
Internal Standard ◽  
Linear Calibration ◽  
Constant Amount ◽  
Factors Affecting ◽  
Analyte Signal ◽  
Calibration Curves ◽  
Electrospray Process

The quantitative aspects of elemental electrospray mass spectrometry are investigated with particular emphasis on the factors affecting the ability to establish linear calibration curves. It is shown that linear calibration curves can be obtained for trace elements if the analyte signal is ratioed to the signal from a constant amount of a similarly charged electrolyte species. Linear calibration curves can be established over a concentration dynamic range of at least four orders of magnitude. The added component seems to function as a stabilizer and monitor of the electrospray process and as an internal standard. In certain cases, species generated by acidification of the solvent may be used as electrospray stabilizers.

Shape sensing of an epidural needle through a network of nanoparticles-doped optical fibers

2021 ◽  
Author(s):  
Aizhan Issatayeva ◽  
Aida Amantayeva ◽  
Wilfried Blanc ◽  
Carlo Molardi ◽  
Daniele Tosi
Keyword(s):  
Optical Fibers ◽  
Epidural Needle ◽  
Shape Sensing

Flexible porphyrin doped polymer optical fibers for rapid and remote detection of trace DNT vapor

The Analyst ◽  
2020 ◽  
Vol 145 (15) ◽  
pp. 5307-5313
Author(s):  
Huan Lin ◽  
Xin Cheng ◽  
Ming-Jie Yin ◽  
Zhouzhou Bao ◽  
Xunbin Wei ◽  
...  
Keyword(s):  
Optical Fiber ◽  
Optical Fibers ◽  
Remote Detection ◽  
Polymer Optical Fiber ◽  
Highly Sensitive ◽  
Polymer Optical Fibers ◽  
Doped Polymer

A flexible porphyrin doped polymer optical fiber was developed for fast and highly sensitive monitoring of DNT vapors.

Shape sensing and feedback control of the catheter robot for interventional surgery

2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Fei Qi ◽  
Bai Chen ◽  
Shigang She ◽  
Shuyuan Gao
Keyword(s):  
Feedback Control ◽  
Control Strategy ◽  
Kinematic Model ◽  
Shape Reconstruction ◽  
Reconstruction Method ◽  
Content Type ◽  
Feedback Control Strategy ◽  
Shape Sensing ◽  
Control Accuracy ◽  
Reconstruction Model

Purpose This paper aims to present a shape sensing method and feedback control strategy based on fiber Bragg grating (FBG) sensor to improve the control accuracy of the robot and ensure the safety of the cardiac interventional surgery. Design/methodology/approach To theoretically describe the shape of the catheter robot, the kinematic model is established by the geometric analysis method. And to obtain the actual shape, a large curvature assemble sensor based on FBG is adopted and a novel simple shape reconstruction model is proposed, which can provide the shape curve and distal position. In addition, the influence of external load on the bending deformation is investigated by experiments. To improve the shape accuracy of the robot, a shape feedback control method is presented to control the catheter robot, which can control the robot to bend into the pre-given desired shape. Findings Experiment results verify the effectiveness of the shape sensing method and the reconstruction model, and the correlation coefficients of three sets of curve in different coordinate directions are 0.9986, 0.9992 and 0.9999. Results of the shape feedback experiment show that the curvature error and direction angle error are 1.42% and 10.3%, respectively. The continuum catheter robot can be controlled to achieve the desired bending shape. Originality/value The shape reconstruction method and feedback control strategy proposed in this paper can improve the control accuracy of the robot to avoid the risk of the collision with the surrounding blood vessels, the tissues and organs.

scholarly journals Properties of Fibrous Concrete Made with Plastic Optical Fibers from E-Waste

Materials ◽  
2020 ◽  
Vol 13 (10) ◽  
pp. 2414 ◽  
Author(s):  
Zbigniew Suchorab ◽  
Małgorzata Franus ◽  
Danuta Barnat-Hunek
Keyword(s):  
Optical Fibers ◽  
Experimental Studies ◽  
Waste Utilization ◽  
Salt Crystallization ◽  
Polymer Optical Fiber ◽  
Bending Tests ◽  
Transition Zones ◽  
Reinforced Beams ◽  
Fibrous Concrete ◽  
Plastic Optical Fibers

This article presents research results relating to the potential for waste utilization in the form of polymer optical fiber (POF) scraps. This material is difficult to recycle due to its diverse construction. Three different volumes of POF were used in concrete in these tests: 1%, 2%, and 3%. The experimental studies investigated the basic properties of the concrete, the elastic and dynamic moduli, as well as deformation and deflection of reinforced beams. The microstructures, including the interfacial transition zones (ITZs), were recorded and analyzed using a scanning electron microscope. It was observed that 180 freezing–thawing cycles reduced the concrete frost resistance containing 3% POFs by half compared to the control concrete. The resistance to salt crystallization of this concrete decreased by about 55%. POFs have significant effects on the splitting tensile and flexural strengths compared to the compressive strength. The control beams were destroyed during the four-point static bending tests at half the force applied to the beams that were reinforced with POFs.

scholarly journals Vortex Polymer Optical Fiber with 64 Stable OAM States

Polymers ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 2776
Author(s):  
José A. Borda-Hernández ◽  
Claudia M. Serpa-Imbett ◽  
Hugo E. Hernandez Figueroa
Keyword(s):  
Optical Fiber ◽  
Optical Fibers ◽  
Communication Systems ◽  
Low Cost ◽  
Higher Order ◽  
Coupling Coefficients ◽  
Polymer Optical Fiber ◽  
Optical Polymer ◽  
Polymer Optical Fibers ◽  
Low Dispersion

This research introduces a numerical design of an air-core vortex polymer optical fiber in cyclic transparent optical polymer (CYTOP) that propagates 32 orbital angular momentum (OAM) modes, i.e., it may support up to 64 stable OAM-states considering left- and right-handed circular polarizations. This fiber seeks to be an alternative to increase the capacity of short-range optical communication systems multiplexed by modes, in agreement with the high demand of low-cost, insensitive-to-bending and easy-to-handle fibers similar to others optical fibers fabricated in polymers. This novel fiber possesses unique characteristics: a diameter of 50 µm that would allow a high mechanical compatibility with commercially available polymer optical fibers, a difference of effective index between neighbor OAM modes of around 10−4 over a bandwidth from 1 to 1.6 µm, propagation losses of approximately 15 × 10−3 dB/m for all OAM modes, and a very low dispersion for OAM higher order modes (±l = 16) of up to +2.5 ps/km-nm compared with OAM lower order modes at a telecom wavelength of 1.3 µm, in which the CYTOP exhibits a minimal attenuation. The spectra of mutual coupling coefficients between modes are computed considering small bends of up to 3 cm of radius and slight ellipticity in the ring of up to 5%. Results show lower-charge weights for higher order OAM modes.

scholarly journals E-Knitted Textile with Polymer Optical Fibers for Friction and Pressure Monitoring in Socks

Sensors ◽  
2019 ◽  
Vol 19 (13) ◽  
pp. 3011 ◽  
Author(s):  
Claire Guignier ◽  
Brigitte Camillieri ◽  
Michel Schmid ◽  
René M. Rossi ◽  
Marie-Ange Bueno
Keyword(s):  
Mechanical Properties ◽  
Optical Fiber ◽  
Optical Fibers ◽  
Knitted Fabric ◽  
Bending Rigidity ◽  
Pressure Monitoring ◽  
Polymer Optical Fiber ◽  
Bending Radius ◽  
Polymer Optical Fibers ◽  
Knitted Structure

The objective of this paper is to study the ability of polymer optical fiber (POF) to be inserted in a knitted fabric and to measure both pressure and friction when walking. Firstly, POF, marketed and in development, have been compared in terms of the required mechanical properties for the insertion of the fiber directly into a knitted fabric on an industrial scale, i.e. elongation, bending rigidity, and minimum bending radius before plastic deformation. Secondly, the chosen optical fiber was inserted inside several types of knitted fabric and was shown to be sensitive to friction and compression. The knitted structure with the highest sensitivity has been chosen for sock prototype manufacturing. Finally, a feasibility study with an instrumented sock showed that it is possible to detect the different phases of walking in terms of compression and friction.

The Dynamic Calibration of Tipping-Bucket Raingauges

1986 ◽  
Vol 17 (3) ◽  
pp. 203-214 ◽  
Author(s):  
Janusz Niemczynowicz
Keyword(s):  
Rainfall Intensity ◽  
Nordic Countries ◽  
Dynamic Calibration ◽  
Calibration Function ◽  
Linear Calibration ◽  
Calibration Curves ◽  
Non Linear ◽  
Rainfall Volume

The dynamic calibration of three types of tipping-bucket raingauges extensively used in the Nordic countries was performed. The tested and calibrated gauges were: “LTH gauge”, PLUMATIC gauge and RIMCO gauge. It was found that with regard to all tested gauges, the volume of water which tips the bucket is not a constant characteristic for the gauge; it depends on rainfall intensity. Thus, in order to avoid errors, a calculation of the rainfall intensity or of rainfall volume from tipping-bucket registrations must go through empirical, usually non-linear calibration function. The procedure involved in the dynamic calibration of the tipping-bucket raingauges is described in the paper. Examples of typical calibration curves are provided. The magnitude of errors, in respect of measured rainfall intensity, which occur when linear gauge calibration is used is stated too.

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