Polymer Optical Fiber Sensors in Wearable Devices: Toward Novel Instrumentation Approaches for Gait Assistance Devices

Leal‐Junior, Arnaldo; Frizera, Anselmo; Vargas-Valencia, Laura; Santos, Wilian M. dos; Bó, Antônio Padilha Lanari; Siqueira, Adriano A. G.; Pontes, María José

doi:10.1109/jsen.2018.2852363

Cited by 64 publications

(35 citation statements)

References 37 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…However, possibility of assessing gait symmetry in real-life conditions depend on using an uncomplicated wearable sensor to estimate vertical CoM displacement. For instance, joint kinematics may be estimated using both inertial sensors [32] or optical fiber [33]. Instrumented insoles may also be used, including for controlling lower-limbs prosthesis [34].…”

Section: Discussionmentioning

confidence: 99%

Symmetry Analysis of Amputee Gait Based on Body Center of Mass Trajectory and Discrete Fourier Transform

Ochoa-Diaz

Bó

2020

Sensors

Self Cite

View full text Add to dashboard Cite

The calculation of symmetry in amputee gait is a valuable tool to assess the functional aspects of lower limb prostheses and how it impacts the overall gait mechanics. This paper analyzes the vertical trajectory of the body center of mass (CoM) of a group formed by transfemoral amputees and non-amputees to quantitatively compare the symmetry level of this parameter for both cases. A decomposition of the vertical CoM into discrete Fourier series (DFS) components is performed for each subject’s CoM trajectory to identify the main components of each pattern. A DFS-based index is then calculated to quantify the CoM symmetry level. The obtained results show that the CoM displays different patterns along a gait cycle for each amputee, which differ from the sine-wave shape obtained in the non-amputee case. The CoM magnitude spectrum also reveals more coefficients for the amputee waveforms. The different CoM trajectories found in the studied subjects can be thought as the manifestation of developed compensatory mechanisms, which lead to gait asymmetries. The presence of odd components in the magnitude spectrum is related to the asymmetric behavior of the CoM trajectory, given the fact that this signal is an even function for a non-amputee gait. The DFS-based index reflects this fact due to the high value obtained for the non-amputee reference, in comparison to the low values for each amputee.

show abstract

Section: Discussionmentioning

confidence: 99%

Symmetry Analysis of Amputee Gait Based on Body Center of Mass Trajectory and Discrete Fourier Transform

Ochoa-Diaz

Bó

2020

Sensors

Self Cite

View full text Add to dashboard Cite

show abstract

“…Among many optical fiber-based sensing approaches, e.g. nonlinear effects [8], intensity variations [9], interferometers [10] and reflectometry [11], fiber Bragg gratings (FBGs) are popularly employed to the measurement of diverse industrial and structural parameters, such as strain, pressure, liquid level, temperature, humidity and even detection of specific chemical compounds [12]. The reason for such widespread use is its high resolution, sensitivity and reliability of such sensing scheme, which is mainly related to their wavelength-encoded data that can be also be used to provide multiplexing capabilities (i.e., the possibility of inscribing dozens of sensors in the same fiber) [13].…”

Section: Introductionmentioning

confidence: 99%

Optimizing Linearity and Sensitivity of 3D-Printed Diaphragms With Chirped FBGs in CYTOP Fibers

et al. 2020

Self Cite

View full text Add to dashboard Cite

We report the development of an optimization approach for diaphragm-embedded optical fiber sensors, which was applied on the pressure, force and liquid level assessment using chirped fiber Bragg gratings (CFBGs) inscribed in cyclic transparent optical polymer (CYTOP) fibers. The inscription was performed using the plane-by-plane method with a femtosecond laser, whereas the diaphragm optimization was performed through the multi-objective particle swarm optimization (MOPSO). The objective functions for the optimization were obtained from numerical simulation using the finite element method of diaphragms with different thickness and diameters. The MOPSO resulted in a set of solutions with thickness and diameter aiming the optimization of sensitivity and linearity of diaphragm-embedded CFBG sensors. Three configurations were chosen with different values sensitivity and linearity. Experimental analysis was performed in each configuration for temperature and pressure variations, where the results confirmed the different sensitivity and linearity levels for each chosen configuration. Two applications were analyzed for the proposed configurations with higher sensitivity and linearity: one for force estimation over a 200-N range and the other for sub-millimeter assessment of liquid level over a 50-cm range. In order to obtain a highly reliable and accurate system, a novel data integration method for chirped FBGs was proposed. In this case, the estimation of force, pressure or liquid level was performed considering the contributions of both wavelength shift and full width half maximum (FWHM) variations. The proposed approach resulted in error improvement of 60% for all cases and for all parameters analyzed.

show abstract

“…However, their necessity for frequent calibration is a drawback in many applications [7]. It is also worth mentioning that all the aforementioned sensing technologies have sensitivity to electromagnetic fields, which is especially undesirable in robotic applications, where there is a constant activation of electric actuators [8]. The sensitivity to electromagnetic fields is also a drawback for the sensors commonly used in the human-robot interaction force assessment (strain gauges, capacitive sensors and piezoelectric sensors) [6].…”

Section: Introductionmentioning

confidence: 99%

Polymer Optical Fiber-Based Integrated Instrumentation in a Robot-Assisted Rehabilitation Smart Environment: A Proof of Concept

Leal‐Junior

Avellar

Jaimes

et al. 2020

Sensors

Self Cite

View full text Add to dashboard Cite

Advances in robotic systems for rehabilitation purposes have led to the development of specialized robot-assisted rehabilitation clinics. In addition, advantageous features of polymer optical fiber (POF) sensors such as light weight, multiplexing capabilities, electromagnetic field immunity and flexibility have resulted in the widespread use of POF sensors in many areas. Considering this background, this paper presents an integrated POF intensity variation-based sensor system for the instrumentation of different devices. We consider different scenarios for physical rehabilitation, resembling a clinic for robot-assisted rehabilitation. Thus, a multiplexing technique for POF intensity variation-based sensors was applied in which an orthosis for flexion/extension movement, a modular exoskeleton for gait assistance and a treadmill were instrumented with POF angle and force sensors, where all the sensors were integrated in the same POF system. In addition, wearable sensors for gait analysis and physiological parameter monitoring were also proposed and applied in gait exercises. The results show the feasibility of the sensors and methods proposed, where, after the characterization of each sensor, the system was implemented with three volunteers: one for the orthosis on the flexion/extension movements, one for the exoskeleton for gait assistance and the other for the free gait analysis using the proposed wearable POF sensors. To the authors’ best knowledge, this is the first time that optical fiber sensors have been used as a multiplexed and integrated solution for the simultaneous assessment of different robotic devices and rehabilitation protocols, where such an approach results in a compact, fully integrated and low-cost system, which can be readily employed in any clinical environment.

show abstract

Polymer Optical Fiber Sensors in Wearable Devices: Toward Novel Instrumentation Approaches for Gait Assistance Devices

Cited by 64 publications

References 37 publications

Symmetry Analysis of Amputee Gait Based on Body Center of Mass Trajectory and Discrete Fourier Transform

Symmetry Analysis of Amputee Gait Based on Body Center of Mass Trajectory and Discrete Fourier Transform

Optimizing Linearity and Sensitivity of 3D-Printed Diaphragms With Chirped FBGs in CYTOP Fibers

Polymer Optical Fiber-Based Integrated Instrumentation in a Robot-Assisted Rehabilitation Smart Environment: A Proof of Concept

Contact Info

Product

Resources

About