scholarly journals Polymer Optical Fiber Goniometer: A New Portable, Low Cost and Reliable Sensor for Joint Analysis

Sensors ◽  
2018 ◽  
Vol 18 (12) ◽  
pp. 4293 ◽  
Author(s):  
Andressa Rezende ◽  
Camille Alves ◽  
Isabela Marques ◽  
Marco Silva ◽  
Eduardo Naves
Keyword(s):  
Optical Fiber ◽  
Electromagnetic Interference ◽  
Joint Angle ◽  
Low Cost ◽  
Measurement Unit ◽  
Joint Analysis ◽  
Polymer Optical Fiber ◽  
Important Indicator ◽  
Feedback Information ◽  
Novel Method

The quantitative measurement of an articular motion is an important indicator of its functional state and for clinical and pathology diagnoses. Joint angle evaluation techniques can be applied to improve sports performance and provide feedback information for prostheses control. Polymer optical fiber (POF) sensors are presented as a novel method to evaluate joint angles, because they are compact, lightweight, flexible and immune to electromagnetic interference. This study aimed to characterize and implement a new portable and wearable system to measure angles based on a POF curvature sensor. This study also aimed to present the system performance in bench tests and in the measurement of the elbow joint in ten participants, comparing the results with a consolidated resistive goniometer. Results showed high repeatability of sensors between cycles and high similarity of behavior with the potentiometer, with the advantage of being more ergonomic. The proposed sensor presented errors comparable to the literature and showed some advantages over other goniometers, such as the inertial measurement unit (IMU) sensor and over other types of POF sensors. This demonstrates its applicability for joint angle evaluation.

scholarly journals Polymer Optical Fiber-Based Respiratory Sensors: Various Designs and Implementations

2019 ◽  
Vol 2019 ◽  
pp. 1-6
Author(s):  
A. Arifin ◽  
Nelly Agustina ◽  
Syamsir Dewang ◽  
Irfan Idris ◽  
Dahlang Tahir
Keyword(s):  
Optical Fiber ◽  
Measurement System ◽  
Output Voltage ◽  
Low Cost ◽  
Optical Fiber Sensor ◽  
Digital Signal ◽  
Analog Signal ◽  
Fiber Sensor ◽  
Polymer Optical Fiber ◽  
Arduino Uno

This research discusses the polymer optical fiber sensor for respiratory measurements. The infrared LED that produces light will propagate along the polymer optical fiber which will be received by the phototransistor and the differential amplifier. The output voltage in the form of an analog signal will be converted to a digital signal by the Arduino Uno microcontroller and displayed on the computer. The polymer optical fiber sensor is installed on the corset using a variety of configuration (straight, sinusoidal, and spiral), placed in the abdomen, and a variety of positions (abdomen, chest, and back) using only a spiral configuration. While doing the inspiration, the stomach will be enlarged so that the optical fiber sensor will have strain. The strain will cause loss of power, the resulting light intensities received by the phototransistor are reduced, and the output voltage on the computer decreases. The result shows that the highest voltage amplitudes were in the spiral configuration placed in the abdominal position for slow respiration measurements with the highest range, sensitivity, and resolution which are 0.119 V, 0.238 V/s, and 0.004 s, respectively. The advantages of our work are emphasized on measurement system simplicity, low cost, easy fabrication, and handy operation and can be connected with the Arduino Uno microcontroller and computer.

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.

Low-cost fused taper polymer optical fiber (LFT-POF) splitters for environmental and home-networking solution

2017 ◽  
Author(s):  
Latifah S. Supian ◽  
Mohammad Syuhaimi Ab-Rahman ◽  
Hadi Guna ◽  
Hazwan Harun ◽  
Malik Sulaiman ◽  
...  
Keyword(s):  
Optical Fiber ◽  
Low Cost ◽  
Polymer Optical Fiber ◽  
Home Networking

Design considerations, analysis, and application of a low-cost, fully portable, wearable polymer optical fiber curvature sensor

2018 ◽  
Vol 57 (24) ◽  
pp. 6927 ◽  
Author(s):  
Arnaldo G. Leal-Junior ◽  
Anselmo Frizera ◽  
Leticia M. Avellar ◽  
Maria José Pontes
Keyword(s):  
Optical Fiber ◽  
Low Cost ◽  
Polymer Optical Fiber ◽  
Design Considerations ◽  
Curvature Sensor

A Novel Method for Large Area Graphene Transfer on the Polymer Optical Fiber

2012 ◽  
Vol 12 (5) ◽  
pp. 3918-3921 ◽  
Author(s):  
Atul Kulkarni ◽  
Hyeongkeun Kim ◽  
Rashid Amin ◽  
Sung Ha Park ◽  
Byung Hee Hong ◽  
...  
Keyword(s):  
Optical Fiber ◽  
Polymer Optical Fiber ◽  
Large Area ◽  
Novel Method ◽  
Graphene Transfer

Research on Non-Gyro Projectile’s Attitude Measurement Based on Improved Unscented Kalman Filter

2011 ◽  
Vol 480-481 ◽  
pp. 1111-1116
Author(s):  
Zhao Hua Liu ◽  
Jia Bin Chen ◽  
Yong Wang ◽  
Chun Lei Song ◽  
Jun Wang ◽  
...  
Keyword(s):  
Kalman Filter ◽  
Unscented Kalman Filter ◽  
Low Cost ◽  
State Equation ◽  
Measurement Unit ◽  
Attitude Measurement ◽  
Good Precision ◽  
Measurement Equation ◽  
Novel Method ◽  
Linear State

Considering the control requirements of guided projectile, a novel method is studied that using three low-cost MEMS accelerometers as inertial measurement unit to construct state equation and measurement equation of system, using improved unscented Kalman filter (IUKF) to estimate the state of system. For the system characteristic of linear state equation and nonlinear measurement equation, the improved UKF nonlinear filter algorithm which combines KF and UKF was proposed. At the same time, utilizing minimal skew simplex sampling to reduce the number of sigma points, computational efficiency is enhanced. The simulation experimental results show that using IUKF algorithm can obtains good precision of estimation.

scholarly journals A Novel Micro-Displacement Sensor Based on Double Optical Fiber Probes Made through Photopolymer Materials

Materials ◽  
2020 ◽  
Vol 13 (23) ◽  
pp. 5475
Author(s):  
Fuzheng Zhang ◽  
Qijing Lin ◽  
Liangquan Zhu ◽  
Na Zhao ◽  
Feng Han ◽  
...  
Keyword(s):  
Optical Fiber ◽  
Correlation Coefficient ◽  
Electromagnetic Interference ◽  
Low Cost ◽  
Optical Power ◽  
High Sensitivity ◽  
Response Speed ◽  
Displacement Sensor ◽  
Optical Fiber Probes ◽  
Fiber Probes

In this paper, a novel micro-displacement sensor with double optical fiber probes is proposed and designed, which can realize the highly sensitive sensing of longitudinal or lateral micro-displacements. The optical fiber probes are made through photopolymer formulation, and the effects of reaction time and optical power on the growth length of the probe are illustrated. The relationship between light intensity and longitudinal micro-displacement is a power function in the range of 0–100 μm at room temperature with a correlation coefficient of 98.92%. For lateral micro-displacement, the sensitivity is −2.9697 dBm/μm in the range of 0–6 μm with a linear fit of 99.61%. In addition, the linear correlation coefficient decreases as the initial longitudinal distance increases, and the function of these correlation coefficients is also linear with a linearity of 96.14%. This sensor has a simple manufacturing process, low cost, high sensitivity, and fast response speed. It is suitable for harsh environments such as strong electromagnetic interference and corrosivity, and has a broad application prospect in the field of micro-displacement sensing.

scholarly journals Polycarbonate mPOF-Based Mach–Zehnder Interferometer for Temperature and Strain Measurement

Sensors ◽  
2020 ◽  
Vol 20 (22) ◽  
pp. 6643
Author(s):  
Xiaoyu Yue ◽  
Haijin Chen ◽  
Hang Qu ◽  
Rui Min ◽  
Getinet Woyessa ◽  
...  
Keyword(s):  
Optical Fiber ◽  
Temperature Measurement ◽  
Temperature Sensitivity ◽  
Strain Measurement ◽  
Linear Response ◽  
Force Measurement ◽  
Low Cost ◽  
Unit Length ◽  
Polymer Optical Fiber ◽  
Increasing Temperature

In this paper, an endlessly single mode microstructured polymer optical fiber (mPOF) in a Mach–Zehnder (M–Z) interferometer configuration is demonstrated for temperature and strain measurement. Because there is no commercial splicer applied for POF-silica optical fiber (SOF) connectorization, prior to the M–Z interferometric sensing, we introduce an imaging projecting method to align a polycarbonate mPOF to a SOF and then the splice is cured permanently using ultraviolet (UV) glue. A He-Ne laser beam at 632.8 nm coupled in a SOF is divided by a 1 × 2 fiber coupler to propagate in two fiber arms. A piece of mPOF is inserted in one arm for sensing implementation and the interference fringes are monitored by a camera. For non-annealed fiber, the temperature sensitivity is found to be 25.5 fringes/°C for increasing temperature and 20.6 fringes/°C for decreasing temperature. The converted sensitivity per unit length is 135.6 fringes/°C/m for increasing temperature, which is twice as much as the silica fiber, or 852.2 rad/°C/m (optical phase change versus fiber temperature), which is more than four times as much as that for the PMMA fiber. To solve the sensitivity disagreement, the fiber was annealed at 125 °C for 36 h. Just after the thermal treatment, the temperature measurement was conducted with sensitivities of 16.8 fringes/°C and 21.3 fringes/°C for increasing and decreasing process, respectively. One month after annealing, the linear response was improved showing a temperature sensitivity of ~20.7 fringes/°C in forward and reverse temperature measurement. For the strain measurement based on non-annealed fiber, the sensitivity was found to be ~1463 fringes/%ε showing repeatable linear response for forward and reverse strain. The fiber axial force sensitivity was calculated to be ~2886 fringes/N, showing a force measurement resolution of ~3.47 × 10−4 N. The sensing methodology adopted in this work shows several advantages, such as very low cost, high sensitivity, a straightforward sensing mechanism, and ease of fabrication.

scholarly journals Reference Frame Unification of IMU-Based Joint Angle Estimation: The Experimental Investigation and a Novel Method

Sensors ◽  
2021 ◽  
Vol 21 (5) ◽  
pp. 1813
Author(s):  
Chunzhi Yi ◽  
Feng Jiang ◽  
Chifu Yang ◽  
Zhiyuan Chen ◽  
Zhen Ding ◽  
...  
Keyword(s):  
Reference Frame ◽  
Reference Frames ◽  
Joint Angle ◽  
Human Subjects ◽  
Local Magnetic Field ◽  
Estimation Accuracy ◽  
Measurement Unit ◽  
Time Varying ◽  
Angle Estimation ◽  
Novel Method

Inertial measurement unit (IMU)-based joint angle estimation is an increasingly mature technique that has a broad range of applications in clinics, biomechanics and robotics. However, the deviations of different IMUs’ reference frames, referring to IMUs’ individual orientations estimating errors, is still a challenge for improving the angle estimation accuracy due to conceptual confusion, relatively simple metrics and the lack of systematical investigation. In this paper, we clarify the determination of reference frame unification, experimentally study the time-varying characteristics of reference frames’ deviations and accordingly propose a novel method with a comprehensive metric to unify reference frames. To be specific, we firstly define the reference frame unification (RFU) and distinguish it with drift correction that has always been confused with the term RFU. Secondly, we design a mechanical gimbal-based experiment to study the deviations, where sensor-to-body alignment and rotation-caused differences of orientations are excluded. Thirdly, based on the findings of the experiment, we propose a novel method to utilize the consistency of the joint axis under the hinge-joint constraint, gravity acceleration and local magnetic field to comprehensively unify reference frames, which meets the nonlinear time-varying characteristics of the deviations. The results on ten human subjects reveal the feasibility of our proposed method and the improvement from previous methods. This work contributes to a relatively new perspective of considering and improving the accuracy of IMU-based joint angle estimation.

scholarly journals A Comparative Study of Markerless Systems Based on Color-Depth Cameras, Polymer Optical Fiber Curvature Sensors, and Inertial Measurement Units: Towards Increasing the Accuracy in Joint Angle Estimation

Electronics ◽  
2019 ◽  
Vol 8 (2) ◽  
pp. 173 ◽  
Author(s):  
Nicolas Valencia-Jimenez ◽  
Arnaldo Leal-Junior ◽  
Leticia Avellar ◽  
Laura Vargas-Valencia ◽  
Pablo Caicedo-Rodríguez ◽  
...  
Keyword(s):  
Optical Fiber ◽  
Correlation Coefficient ◽  
Joint Angle ◽  
Vision System ◽  
Inertial Measurement Units ◽  
Polymer Optical Fiber ◽  
Angle Estimation ◽  
Inertial Measurement ◽  
Non Invasive ◽  
Measurement Units

This paper presents a comparison between a multiple red green blue-depth (RGB-D) vision system, an intensity variation-based polymer optical fiber (POF) sensor, and inertial measurement units (IMUs) for human joint angle estimation and movement analysis. This systematic comparison aims to study the trade-off between the non-invasive feature of a vision system and its accuracy with wearable technologies for joint angle measurements. The multiple RGB-D vision system is composed of two camera-based sensors, in which a sensor fusion algorithm is employed to mitigate occlusion and out-range issues commonly reported in such systems. Two wearable sensors were employed for the comparison of angle estimation: (i) a POF curvature sensor to measure 1-DOF angle; and (ii) a commercially available IMUs MTw Awinda from Xsens. A protocol to evaluate elbow joints of 11 healthy volunteers was implemented and the comparison of the three systems was presented using the correlation coefficient and the root mean squared error (RMSE). Moreover, a novel approach for angle correction of markerless camera-based systems is proposed here to minimize the errors on the sagittal plane. Results show a correlation coefficient up to 0.99 between the sensors with a RMSE of 4.90 ∘ , which represents a two-fold reduction when compared with the uncompensated results (10.42 ∘ ). Thus, the RGB-D system with the proposed technique is an attractive non-invasive and low-cost option for joint angle assessment. The authors envisage the proposed vision system as a valuable tool for the development of game-based interactive environments and for assistance of healthcare professionals on the generation of functional parameters during motion analysis in physical training and therapy.

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