A flexible micromachined optical sensor for simultaneous measurement of pressure and shear force distribution on foot

Wang, Wei‐Chih; Panergo, Reynold R.; Galvanin, Christopher M.; Ledoux, William R.; Sangeorzan, Bruce J.; Reinhall, Per G.

doi:10.1117/12.483932

Cited by 6 publications

(6 citation statements)

References 6 publications

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“…Study shows that plantar ulceration of the foot is closely related to the diabetic foot and can lead to amputation with increased mortality rate [2]. Many studies report that shear combined with pressure is associated with ulcer incidences [3][4][5][6][7][8][9][10]. However, the exact relationship between stresses and ulcer formation is still a mist.…”

Section: Introductionmentioning

confidence: 99%

An offset multilayered optic sensor for shear and pressure measurement

Liu

Chou

Lyu

et al. 2008

Health Monitoring of Structural and Biological Systems 2008

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Simultaneous recording of shear and pressure is an important requirement for study the causes of foot ulceration. In order to obtain a more robust and meaningful picture of what is occurring on the plantar surface of the foot, we have developed a multi-layered optical bend loss sensor that can be accommodated for shear and pressure measurement of an extended area. The sensor is made of two layers of crisscross fiberoptic sensor array separated by an elastomeric layer.Each sensing layer has multiple fibers molded into a thin polydimethylsiloxane (PDMS) substrate to form a mesh array.The top layer uses 6 fibers to create a 3 by 3 mesh with 9 intersection points and the bottom layer uses 8 fibers to create a 4 by 4 mesh with 16 intersection points. The space between the adjacent fibers is 0.5cm. Measuring changes of light intensity transmitted through the fiber provides information about the force induced changes of the fiber's radius of curvature. Pressure is measured based on the force induced light loss from the two affected crossing fibers divided by each sensing area. Shear was measured based on the relative position changes on these pressure points between the two fiber mesh layers. The design is an offset layout because the intersection points of the top and bottom layer are offset by 0.25 cm which can increase the shear sensing sensitivity. For testing the sensor with various loading condition, a neural network algorithm is induced to identify the loading pattern and the shear direction. Three loading patterns with 5 different loading directions were tested and a >90% accuracy was obtained using an algorithm using 2 neural networks.

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Section: Introductionmentioning

confidence: 99%

An offset multilayered optic sensor for shear and pressure measurement

Liu

Chou

Lyu

et al. 2008

Health Monitoring of Structural and Biological Systems 2008

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“…A flexible high-resolution sensor capable of measuring the distribution of both shear and pressure at the plantar interface are needed to study the actual distribution of this force during daily activities, and the role that shear plays in causing plantar ulceration [1][2][3][4][5][6][7]. We have previously developed a novel means of transducing plantar shear and pressure stress via a new microfabricated optical system [1][2][3].…”

Section: Introductionmentioning

confidence: 99%

“…We have previously developed a novel means of transducing plantar shear and pressure stress via a new microfabricated optical system [1][2][3]. The uniqueness of the system is in its batch fabrication process, which involves an injection molding technique with Polydimethylsiloxane (PDMS) as the optical medium.…”

Section: Introductionmentioning

confidence: 99%

<title>Developments of a force image algorithm for micromachined optical bend loss sensor</title>

et al. 2005

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A flexible high-resolution sensor capable of measuring the distribution of both shear and pressure at the plantar interface are needed to study the actual distribution of this force during daily activities, and the role that shear plays in causing plantar ulceration. We have previously developed a novel means of transducing plantar shear and pressure stress via a new microfabricated optical system. However, a force image algorithm is needed to handle the complexity of construction of two-dimensional planar pressure and shear images. Here we have developed a force image algorithm for a micromachined optical bend loss sensor. A neural network is introduced to help identify different load shapes. According to the experimental result, we can conclude that once the neural network has been well trained, it can correctly identify the loading shape. With the neural network, our micromachined optical bend loss Sensor is able to construction the two-dimensional planar force images.

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“…For the resistive and piezoelectric based shear sensors, these sensors suffer from the same problems as the capacitive sensors in lack of proper electronics support. It also suffers from thermal drift, electrical and mechanical hysteresis, and electromagnetic interference problems that plague most electromagnetic sensors, which we have discussed in our previous papers [3,4,5]. To prevent electromagnetic interference caused by the surroundings and also by the human body, Missinne [10], has reported an optical tactile sensors similar to the current capacitive sensors design, where shear and normal displacement is observed by the relative change in the displacement between the top and bottom sensing layer.…”

Section: Introductionmentioning

confidence: 99%

“…Previously, we have reported a distributive pressure/shear sensor using bend loss sensor [3,4,5,6,7,11,12]. The sensor is composed of two optic fiber meshes which are embedded into a PDMS pad so that fibers' radius of curvatures change when the sensor is pressed.…”

Section: Introductionmentioning

confidence: 99%

Platform-based Shear Force Sensor

Wang

Chang

Tsui

2015

MATEC Web of Conferences

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Abstract. In this paper, we will present the development of a flexible fiber optic bend loss sensor for the measurement of plantar pressure and shear stress for diabetic patients. The sensor will allow the measurement of shear stress on the foot, which is a critical parameter in studying diabetic foot ulcers. The basic configuration of the optical sensor systems incorporates a mesh that is comprised of two sets of parallel optical waveguide planes; the planes are configured so the parallel rows of waveguides of the top and bottom planes are perpendicular to each other. The planes are sandwiched together creating one sensing sheet. Two-dimensional information is determined by measuring the loss of light from each of the waveguide to map the overall pressure distribution. The shifting of the layers relative to each other produces different patterns of the sensor output, and shear force information is characterized through repeated training of the sensor and analysis of the training data. The latest development and improvement in the sensors design is presented. Fabrication and sensor characterization results will be presented.

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A flexible micromachined optical sensor for simultaneous measurement of pressure and shear force distribution on foot

Cited by 6 publications

References 6 publications

An offset multilayered optic sensor for shear and pressure measurement

An offset multilayered optic sensor for shear and pressure measurement

<title>Developments of a force image algorithm for micromachined optical bend loss sensor</title>

Platform-based Shear Force Sensor

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