Distributed Measurement of Deformation Magnitude and Location with a Pair of Soft Sensors

AbstractThis paper presents the performance analysis of the system for real-time reconstruction of the shape of the rigid medical needle used for minimally invasive surgeries. The system is based on four optical fibers glued along the needle at 90 degrees from each other to measure distributed strain along the needle from four different sides. The distributed measurement is achieved by the interrogator which detects the light scattered from each section of the fiber connected to it and calculates the strain exposed to the fiber from the spectral shift of that backscattered light. This working principle has a limitation of discriminating only a single fiber because of the overlap of backscattering light from several fibers. In order to use four sensing fibers, the Scattering-Level Multiplexing (SLMux) methodology is applied. SLMux is based on fibers with different scattering levels: standard single-mode fibers (SMF) and MgO-nanoparticles doped fibers with a 35–40 dB higher scattering power. Doped fibers are used as sensing fibers and SMFs are used to spatially separate one sensing fiber from another by selecting appropriate lengths of SMFs. The system with four fibers allows obtaining two pairs of opposite fibers used to reconstruct the needle shape along two perpendicular axes. The performance analysis is conducted by moving the needle tip from 0 to 1 cm by 0.1 cm to four main directions (corresponding to the locations of fibers) and to four intermediate directions (between neighboring fibers). The system accuracy for small bending (0.1–0.5 cm) is 90$$\%$$ % and for large bending (0.6–1 cm) is approximately 92$$\%$$ % .

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The effect of net latency on the uncertainty in distributed measurement systems

IMTC/2002. Proceedings of the 19th IEEE Instrumentation and Measurement Technology Conference (IEEE Cat. No.00CH37276) ◽

10.1109/imtc.2002.1007139 ◽

2003 ◽

Cited By ~ 3

Author(s):

L. Cristaldi ◽

A. Ferrero ◽

C. Muscas ◽

S. Salicone ◽

R. Tinarelli

Keyword(s):

Measurement Systems ◽

Distributed Measurement Systems ◽

Distributed Measurement

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A Soft Resistive Sensor with a Semicircular Cross-Sectional Channel for Soft Cardiac Catheter Ablation

Sensors ◽

10.3390/s21124130 ◽

2021 ◽

Vol 21 (12) ◽

pp. 4130

Author(s):

Eric Rasmussen ◽

Daniel Guo ◽

Vybhav Murthy ◽

Rachit Mishra ◽

Cameron Riviere ◽

...

Keyword(s):

Catheter Ablation ◽

Liquid Metal ◽

Force Feedback ◽

Applied Force ◽

Medical Community ◽

Soft Robotics ◽

Soft Sensors ◽

Cross Sectional ◽

Cardiac Catheter ◽

Specific Loading

The field of soft robotics has attracted the interest of the medical community due to the ability of soft elastic materials to traverse the abnormal environment of the human body. However, sensing in soft robotics has been challenging due to the sensitivity of soft sensors to various loading conditions and the nonlinear signal responses that can arise under extreme loads. Ideally, soft sensors should provide a linear response under a specific loading condition and provide a different response for other loading directions. With these specifications in mind, our team created a soft elastomeric sensor designed to provide force feedback during cardiac catheter ablation surgery. Analytical and computational methods were explored to define a relationship between resistance and applied force for a semicircular, liquid metal filled channel in the soft elastomeric sensor. Pouillet’s Law is utilized to calculate the resistance based on the change in cross-sectional area resulting from various applied pressures. FEA simulations were created to simulate the deformation of the sensor under various loads. To confirm the validity of these simulations, the elastomer was modeled as a neo-Hookean material and the liquid metal was modeled as an incompressible fluid with negligible shear modulus under uniaxial compression. Results show a linearly proportional relationship between the resistance of the sensor and the application of a uniaxial force. Altering the direction of applied force results in a quadratic relationship between total resistance and the magnitude of force.

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A Multiplexed Optical Fiber Sensor System For Distributed Measurement Of Structural Strains

MRS Proceedings ◽

10.1557/proc-503-119 ◽

1997 ◽

Vol 503 ◽

Author(s):

F. Ansari ◽

Z. Chen ◽

Q. Li

Keyword(s):

Optical Fiber ◽

Optical Switch ◽

Optical Fiber Sensor ◽

Fiber Material ◽

Smart Structure ◽

Sensor System ◽

Fiber Sensor ◽

Fiber Sensors ◽

Large Structures ◽

Distributed Measurement

ABSTRACTStructurally integrated optical fiber sensors form the basis for smart structure technology. Over the past decade a variety of sensor configurations have been developed for measurement of strains and deformations in structures. Strains and deformations alter the refractive index and the geometry of the optical fiber material. These changes perturb the intensity, phase, and polarization of the light-wave propagating along the probing fiber. The optical perturbations are detected for the determination of strain. The research presented here describes the development of a new optical fiber sensor system for measurement of structural strains based on white light interferometry. An optical switch provides for multiplexing of strain signals from various locations in the structure. Redundant Bragg grating type fiber optic sensors as well as strain gauges were employed for comparison and verification of strain signals as measured by the new system. The system provides capability for distributed sensing of strains in large structures.

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