Polymer Optical Fiber for Angle and Torque Measurements of a Series Elastic Actuator's Spring

Leal‐Junior, Arnaldo; Frizera, Anselmo; Marques, Carlos; Sanchez, Manuel R.; Santos, Wilian M. dos; Siqueira, Adriano A. G.; Segatto, Marcelo E. V.

doi:10.1109/jlt.2017.2789192

Cited by 76 publications

(23 citation statements)

References 21 publications

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“…The use of this technique allows the sensitivity control through the length and depth of the sensitive zone, as well as the roughness of its surface area [16]. The sensitive zone is on the convex side of the fiber, thus, with its curvature there is a reduction of reflections on the concave side, so that the rays escape, causing a signal attenuation, which increases with the curvature rise [17]. With different bending, it is possible to change the angle between the sensitive zone and the incident ray, changing the photodiode reading.…”

Section: Introductionmentioning

confidence: 99%

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

Rezende

Alves

Marques

et al. 2018

Sensors

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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.

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Section: Introductionmentioning

confidence: 99%

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

Rezende

Alves

Marques

et al. 2018

Sensors

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“…Referring to Figure 3 , the response’s transitions around 280 s and 400 s were related to the process of applying the torque on the fiber and were due to its viscoelastic behavior, which led to a non-constant response of the polymer with stress or strain [ 33 ]. The polymer viscoelasticity caused the transient behavior of the response around 280 s and 420 s, at which times there were sudden increases followed by polymer relaxation when the torque was applied, as characterized in [ 34 , 35 ]. It is worth mentioning that polymer relaxation is an intrinsic behavior of the POF used, which occurred for all of the torques tested.…”

Section: Resultsmentioning

confidence: 99%

Measurement of Temperature and Relative Humidity with Polymer Optical Fiber Sensors Based on the Induced Stress-Optic Effect

Leal‐Junior

Frizera

Marques

et al. 2018

Sensors

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This paper presents a system capable of measuring temperature and relative humidity with polymer optical fiber (POF) sensors. The sensors are based on variations of the Young’s and shear moduli of the POF with variations in temperature and relative humidity. The system comprises two POFs, each with a predefined torsion stress that resulted in a variation in the fiber refractive index due to the stress-optic effect. Because there is a correlation between stress and material properties, the variation in temperature and humidity causes a variation in the fiber’s stress, which leads to variations in the fiber refractive index. Only two photodiodes comprise the sensor interrogation, resulting in a simple and low-cost system capable of measuring humidity in the range of 5–97% and temperature in the range of 21–46 °C. The root mean squared errors (RMSEs) between the proposed sensors and the reference were 1.12 °C and 1.36% for the measurements of temperature and relative humidity, respectively. In addition, fiber etching resulted in a sensor with a 2 s response time for a relative humidity variation of 10%, which is one of the lowest recorded response times for intrinsic POF humidity sensors.

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“…POF-based sensing techniques can be classified on intensity modulation sensing, Brillouin scattering, and wavelength sensitivity grating devices. Bilro et al [28] presented a review paper about intensity modulation sensing, where all sensors include a light source, an optical fiber, and an optical spectrum analyzer or a photodetector when the accuracy is not so critical, such as structural health monitoring [27,29], deformation monitoring [30], medical instrument [31][32][33][34], environment monitoring [35,36], mechanical measurement [37][38][39], and chemical detection [40,41]. The second technique, based on Brillouin scattering in POFs [26], is mainly focused towards distributed sensing, such as structural health monitoring by POF strain sensor technology [42], according to the fundamental properties of Brillouin scattering in POF as reviewed by Mizuno et al [43].…”

Section: Introductionmentioning

confidence: 99%

Latest Achievements in Polymer Optical Fiber Gratings: Fabrication and Applications

2019

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Polymer Optical Fiber for Angle and Torque Measurements of a Series Elastic Actuator's Spring

Cited by 76 publications

References 21 publications

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

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

Measurement of Temperature and Relative Humidity with Polymer Optical Fiber Sensors Based on the Induced Stress-Optic Effect

Latest Achievements in Polymer Optical Fiber Gratings: Fabrication and Applications

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