Experimental investigation on optical spectral deformation of embedded FBG sensors

this paper presents a low profile stretch sensor for integration into soft structures, robots and wearables. The sensor mechanism uses a single piece of highly flexible and light weight optical fibre and is based on the notion that bending an optical fibre modulates the intensity of the light transmitted through the fibre, a technique often referred as macrobending light loss. In this arrangement, the optical fibre originates from sensor's electronic unit, passes through a stretchable encasing structure in a macrobend pattern, and then loop back to the same unit resulting in a simplified electrical and optical design; the closed optical loop allows for no electronics at one end of the sensor making it safe for human robotics applications, and no optical interference with the external environment eliminating the need for complex conditioning circuitries. Of particular interest of the soft robotics community, the ability of this custom macrobend stretch sensor to flexibly adapt its configuration allows preserving the inherent softness and compliance of the robot which it is installed on. Our experimental results indicate that the optical fibre's bending radius is the dominant design parameter for sufficiently complex patterns, a finding that can facilitate generalisation of the sensing methods across different scales. The measurement performance of the mechanism and its impact on the stiffness of the encasing structure is benchmarked against a custom calibration and testing system. I.

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“…strain conditions. If they are subjected to a non-uniform strain field, the strain compensation is complex [23].…”

Section: Low Profile Stretch Sensor For Soft Wearable Roboticsmentioning

confidence: 99%

Low profile stretch sensor for soft wearable robotics

Sareh

Noh

2018

2018 IEEE International Conference on Soft Robotics (RoboSoft)

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“…Applied stress on the fiber Bragg grating in the direction of the fiber axis results in the extension of its physical dimensions and in the change of the periodic variation; however, the influence of temperature also affects physical dimensions due to thermal expansion. Mathematically, the shift in the Bragg wavelength λ Bragg due to an applied strain and temperature change is given by [ 27 ]:

22

where l is the FBG length and T is temperature. Similar deformation tests with FBGs were published in [ 28 ].…”

Section: Sensor Designmentioning

confidence: 99%

Design of a Pressure Sensor Based on Optical Fiber Bragg Grating Lateral Deformation

Urban

Kadlec

Vlach

et al. 2010

Sensors

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This paper describes steps involved in the design and realization of a new type of pressure sensor based on the optical fiber Bragg grating. A traditional pressure sensor has very limited usage in heavy industrial environments, particularly in explosive or electromagnetically noisy environments. Utilization of optics in these environments eliminates all surrounding influences. An initial motivation for our development was the research, experimental validation, and realization of a complex smart pressure sensor based on the optical principle. The main benefit of this solution consists of increasing sensitivity, resistance to electromagnetic interference, dimensions, and potential increased accuracy.

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“…The FBG sensors are highly sensitive to the change in environmental temperature and strain. In the case of a non-uniform strain field the strain compensation is complex [13], [14]. Shape sensing based on FBG is not suitable for extensible systems.…”

Section: Introductionmentioning

confidence: 99%

A 7.5mm Steiner chain fibre-optic system for multi-segment flex sensing

Sareh

Noh

Ranzani

et al. 2015

2015 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS)

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this paper presents an extensible highly compact fiber-optic system for multi-segment flex sensing. This fiber-optic arrangement is 7.5 mm in diameter and is comprised of a flexible and stretchable Steiner chain (n=12) housing at the top which accommodates passive cables used for sensing, followed by a basal rigid fiber-optic sensing unit. The U-shape loopback design of the sensing system allows integration of electronics on one side and away from the sensing region. A low-friction retractable distance modulation array is designed and implemented to reduce the hysteresis and recover reference sensor values when the arm returns to its original straight configuration. This sensing system is able to measure the dynamic flex patterns of the actuation system to which it conforms. This sensing system can also be embedded inside soft robotic manipulators for multi-segment flex sensing independent of actuation systems, temperature or external load from the environment. This arrangement can also be used as a complete manipulation system when actuating tendons are attached. I.

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Experimental investigation on optical spectral deformation of embedded FBG sensors

Cited by 16 publications

References 6 publications

Low profile stretch sensor for soft wearable robotics

Low profile stretch sensor for soft wearable robotics

Design of a Pressure Sensor Based on Optical Fiber Bragg Grating Lateral Deformation

A 7.5mm Steiner chain fibre-optic system for multi-segment flex sensing

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