Frictional resistance model for tissue-capsule endoscope sliding contact in the gastrointestinal tract

Sliker, Levin J.; Ciuti, Gastone; Rentschler, Mark E.; Menciassi, Arianna

doi:10.1016/j.triboint.2016.06.003

Cited by 47 publications

(30 citation statements)

References 36 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Since the experiments last limited times, we may assume that t 0 equal the elapsed time t e of the experiments. The results of data fittings available in the literature [5,48,49,76,87,92,94,129,133,134,137,145] reveal that the relaxation times form two groups: relaxation times less than the elapsed time τ i < t e ⇒ τ i /t e < 1 and relaxation time greater than the elapsed time τ i > t e ⇒ τ i /t e > 1. Consequently, there are two groups of fractional orders α i , namely: (i) For τ i /t e < 1, we have α i ∈ [0.5, 1] related to fast relaxations and (ii) for τ i /t e > 1, we have α i ∈ (0.5, 1] modelling slow relaxations.…”

Section: Fractional Parameters: Relation To the Relaxation Time Spectrummentioning

confidence: 99%

See 1 more Smart Citation

Response functions in linear viscoelastic constitutive equations and related fractional operators

Hristov

2019

Math. Model. Nat. Phenom.

View full text Add to dashboard Cite

This study addresses the stress–strain relaxation functions of solid polymers in the framework of the linear viscoelasticity with aim to establish the adequate fractional operators emerging from the hereditary integrals. The analysis encompasses power-law and non-power-law materials, thus allowing to see the origins of application of the tools of the classical fractional calculus with singular memory kernels and the ideas leading towards fractional operators with non-singular (regular) kernels. A step ahead in modelling with hereditary integrals is the decomposition of non-power-law relaxation curves by Prony series, thus obtaining discrete relaxation kernels with a finite number of terms. This approach allows for seeing the physical background of the newly defined Caputo–Fabrizio time fractional derivative and demonstrates how other constitutive equations could be modified with non-singular fading memories. The non-power-law relaxation curves also allow for approximations by the Mittag–Leffler function of one parameter that leads reasonably into stress–strain hereditary integrals in terms of Atangana–Baleanu fractional derivative of Caputo sense. The main outcomes of the analysis done are the demonstrated distinguishes between the relaxation curve behaviours of different materials and are therefore the adequate modelling with suitable fractional operators.

show abstract

Section: Fractional Parameters: Relation To the Relaxation Time Spectrummentioning

confidence: 99%

“…According to Drozdov [49], short-term relaxation tests can be successfully approximated by 2-4 terms of truncated Prony series (see also [5,87,92,94,137]). For long-term relaxation tests, 10-15 terms are needed to fit the experimental data [43,48,76,89,115].…”

Section: Discrete Relaxation Spectrum By Prony Series Decompositionmentioning

confidence: 99%

Response functions in linear viscoelastic constitutive equations and related fractional operators

Hristov

2019

Math. Model. Nat. Phenom.

View full text Add to dashboard Cite

show abstract

“…The number of the exponential terms in Equation (39) depends on the accuracy of data fitting. Commonly fourth-order Prony series fit adequately the stress-relaxation data in cases of non-linear viscoelastic behaviors [62,[87][88][89][90][91][92][93], while long-term relaxation tests need 10-15 terms [76,85,[94][95][96][97][98][99][100]. In general, the problem corresponds to identifications of the kernel of an integral Fredholm equation which, actually, is ill-posed problem [68,[101][102][103] requiring Tikhonov regularization [104].…”

Section: Prony Series Decompositionsmentioning

confidence: 99%

Linear Viscoelastic Responses: The Prony Decomposition Naturally Leads Into the Caputo-Fabrizio Fractional Operator

Hristov

2018

Front. Phys.

View full text Add to dashboard Cite

The study addresses the physical background and modeling of linear viscoelastic response functions and their reasonable relationships to the Caputo-Fabrizio fractional operator via the Prony (Dirichlet series) series decomposition. The problem of interconversion with power-law and exponential (single and multi-term functions) has been discussed. Special attentions have been paid on the Prony series decomposition approach, the related interconversion problems and the expression of the viscoelastic constitutive equations in terms of Caputo-Fabrizio fractional operator.

show abstract

“…On the other hand, the endoscope applies on the top wall a combination of magnetic force, reaction force from the endoscope body's bending stiffness, and forces from friction and tissue deformation. Although effects of tissue deformation are not considered here, they have been investigated in [28]. Note that the aforementioned negligible distributed load and the reaction force on the endoscope from the endoscope body's bending are similar in magnitude; however, the loads are distributed differently.…”

Section: Validationmentioning

confidence: 99%

Autonomous Retroflexion of a Magnetic Flexible Endoscope

Slawinski

Taddese

Musto

et al. 2017

IEEE Robot. Autom. Lett.

View full text Add to dashboard Cite

Retroflexion during colonoscopy is typically only practiced in the wider proximal and distal ends of the large intestine owing to the stiff nature of the colonoscope. This inability to examine the proximal side of the majority of colon folds contributes to today's suboptimal colorectal cancer detection rates. We have developed an algorithm for autonomous retroflexion of a flexible endoscope that is actuated magnetically from the tip. The magnetic wrench applied on the tip of the endoscope is optimized in real-time with data from pose detection to compute motions of the actuating magnet. This is the first example of a completely autonomous maneuver by a magnetic endoscope for exploration of the gastrointestinal tract. The proposed approach was validated in plastic tubes of various diameters with a success rate of 98.8% for separation distances up to 50 mm. Additionally, a set of trials was conducted in an excised porcine colon observing a success rate of 100% with a mean time of 19.7 s. In terms of clinical safety, the maximum stress that is applied on the colon wall with our methodology is an order of magnitude below what would damage tissue.

show abstract

Frictional resistance model for tissue-capsule endoscope sliding contact in the gastrointestinal tract

Cited by 47 publications

References 36 publications

Response functions in linear viscoelastic constitutive equations and related fractional operators

Response functions in linear viscoelastic constitutive equations and related fractional operators

Linear Viscoelastic Responses: The Prony Decomposition Naturally Leads Into the Caputo-Fabrizio Fractional Operator

Autonomous Retroflexion of a Magnetic Flexible Endoscope

Contact Info

Product

Resources

About