Modeling of a Flexible Instrument to Study its Sliding Behavior Inside a Curved Endoscope

2012 ◽  
Vol 8 (3) ◽  
Author(s):  
Jitendra P. Khatait ◽  
Dannis M. Brouwer ◽  
Ronald G. K. M. Aarts ◽  
Just L. Herder
Keyword(s):  
Static Friction ◽  
Surgical Instrument ◽  
Bending Rigidity ◽  
Stick Slip ◽  
Multibody Modeling ◽  
Beam Elements ◽  
Flexible Instrument ◽  
The Coefficient Of Friction ◽  
Flexible Instruments

Flexible instruments are increasingly used to carry out surgical procedures. The instrument tip is remotely controlled by the surgeon. The flexibility of the instrument and the friction inside the curved endoscope jeopardize the control of the instrument tip. Characterization of the surgical instrument behavior enables the control of the tip motion. A flexible multibody modeling approach was used to study the sliding behavior of the instrument inside a curved endoscope. The surgical instrument was modeled as a series of interconnected planar beam elements. The curved endoscope was modeled as a rigid curved tube. A static friction-based contact model was implemented. The simulations were carried out both for the insertion of the flexible instrument and for fine manipulation. A computer program (SPACAR) was used for the modeling and simulation. The simulation result shows the stick-slip behavior and the motion hysteresis because of the friction. The coefficient of friction has a large influence on the motion hysteresis, whereas the bending rigidity of the instrument has little influence.

Flexible Multibody Modeling of a Surgical Instrument Inside an Endoscope

2013 ◽  
Vol 9 (1) ◽  
Author(s):  
Jitendra P. Khatait ◽  
Dannis M. Brouwer ◽  
J. P. Meijaard ◽  
Ronald G. K. M. Aarts ◽  
Just L. Herder
Keyword(s):  
Surgical Instrument ◽  
Force Transmission ◽  
Positional Accuracy ◽  
Multibody Modeling ◽  
Multibody Model ◽  
Beam Elements ◽  
Spatial Beam ◽  
Flexible Multibody ◽  
Input Motion ◽  
Flexible Instruments

The implementation of flexible instruments in surgery necessitates high motion and force fidelity and good controllability of the tip. However, the positional accuracy and the force transmission of these instruments are jeopardized by the friction, the clearance, and the inherent compliance of the instrument. The surgical instrument is modeled as a series of interconnected spatial beam elements. The endoscope is modeled as a rigid curved tube. The stiffness, damping, and friction are defined in order to calculate the interaction between the instrument and the tube. The effects of various parameters on the motion and force transmission behavior were studied for the axially-loaded and no-load cases. The simulation results showed a deviation of 1.8% in the estimation of input force compared with the analytical capstan equation. The experimental results showed a deviation on the order of 1.0%. The developed flexible multibody model is able to demonstrate the characteristic behavior of the flexible instrument for both the translational and rotational input motion for a given set of parameters. The developed model will help us to study the effects of various parameters on the motion and force transmission of the instrument.

scholarly journals Modelling and Simulation of a Flexible Endoscopic Surgical Instrument in a Tube

2011 ◽  
Author(s):  
J. P. Khatait ◽  
M. Krijnen ◽  
J. P. Meijaard ◽  
R. G. K. M. Aarts ◽  
D. M. Brouwer ◽  
...  
Keyword(s):  
Circular Cross Section ◽  
The Body ◽  
Modelling And Simulation ◽  
Analysis Tool ◽  
Surgical Instrument ◽  
Bending Rigidity ◽  
Stick Slip ◽  
Friction Forces ◽  
Flexible Instrument ◽  
Access Channel

Flexible instruments are increasingly used to carry out complex procedures in many surgical interventions. The instrument tip is remotely controlled by the surgeon. The inherent flexibility of the instrument, coupled with the friction inside the endoscope access channel and the convoluted shape of the endoscope inside the body, makes the control of the instrument tip difficult and complicated. The objective of this paper is to model and to simulate a flexible endoscopic surgical instrument inside a tube and characterize its behaviour. The surgical instrument is modelled as a series of interconnected beam elements. The endoscope channel is modelled as a rigid tube of uniform circular cross-section. A planar model of the flexible instrument with friction is considered in this paper. Normal reaction and friction forces are calculated at the nodes. A Stribeck based continuous friction model with increased friction at low velocity is implemented in the model. Simulations are carried out both for the insertion of the flexible instrument and for fine manipulation. SPACAR, an analysis tool for flexible multibody dynamic systems, has been used for the modelling and simulation. The nodal displacement and force acting at the various nodes have been obtained depending on position and time. The simulation for the fine tip manipulation shows the stick-slip behaviour and hysteresis. The simulation results show the effect of bending rigidity and friction on motion hysteresis.

Frictional Vibrations

1955 ◽  
Vol 22 (2) ◽  
pp. 207-214
Author(s):  
David Sinclair
Keyword(s):  
Coefficient Of Friction ◽  
Equations Of Motion ◽  
Static Friction ◽  
Uniform Motion ◽  
Friction Characteristic ◽  
Stick Slip ◽  
The Coefficient Of Friction ◽  
Brake Lining ◽  
Solid Bodies ◽  
Frictional Vibrations

Abstract Frictional vibrations, such as stick-slip motion and automobile-brake squeal, which occur when two solid bodies are rubbed together, are analyzed mathematically and observed experimentally. The conditions studied are slow uniform motion and relatively rapid simple harmonic motion of brake lining over a cast-iron base. The equations of motion show and the observations confirm that frictional vibrations are caused primarily by an inverse variation of coefficient of friction with sliding velocity, but their form and occurrence are greatly dependent upon the dynamical constants of the mechanical system. With a constant coefficient of friction, the vibration initiated whenever sliding begins is rapidly damped out, not by the friction but by the “natural” damping of all mechanical systems. The coefficient of friction of most brake linings and other organic materials was essentially invariant with velocity, except that the static coefficient was usually greater than the sliding coefficient. Most such materials usually showed a small decrease in coefficient with increasing temperature. The persistent vibrations resulting from the excess static friction were reduced or eliminated by treating the rubbing surfaces with polar organic compounds which produced a rising friction characteristic.

scholarly journals Effect of Stick - Slip Phenomena between Human Skin and UHMW Polyethylene

2021 ◽  
Vol 29 (3) ◽  
Author(s):  
Emad Kamil Hussein ◽  
Kussay Ahmed Subhi ◽  
Tayser Sumer Gaaz
Keyword(s):  
Friction Coefficient ◽  
Human Skin ◽  
Coefficient Of Friction ◽  
Normal Load ◽  
Static Friction ◽  
Time Interval ◽  
Dynamic Friction ◽  
Sliding Velocity ◽  
Stick Slip ◽  
The Coefficient Of Friction

The present paper investigates experimentally effect of applied load and different velocity on the coefficient of friction between two interacting surfaces (human skin and Ultra-high-molecular-weight polyethylene (UHMW- polyethylene) at static and dynamic friction. It is possible to conclude specific point based on the above practical part and frictional analysis of this investigation as the most important mechanical phenomenon was creep has been observed a stick time interval where the static friction force is significantly increased during this stroke. The analytical model for stick-slip of skin and UHMWPE is proposed. The difference between static and kinetic friction defines the amplitude of stick-slip phenomena. The contact pressure, the sliding velocity, and rigidity of system determine the stability conditions of the movement between skin and UHMWPE. Experiments were carried out by developing a device (friction measurement). Variations of friction coefficient during the time at different normal load 4.6 and 9.2 N and low sliding velocity 4, 5, 6 and 7 mm/min were experimentally investigated. The results showed that the friction coefficient varied with the normal load and low sliding velocity. At static friction, the coefficient of friction decreased when the time increases, whereas, at dynamic friction, the coefficient of friction decreased when the time increased at normal load 4.6 and 9.2 N.

Experimental Characterization of a Flexible Two-Link Manipulator Arm

1993 ◽  
Author(s):  
Randall L. Mayes ◽  
G. Richard Eisler
Keyword(s):  
Element Model ◽  
Input Voltage ◽  
Analytical Models ◽  
Experimental Characterization ◽  
Frequency Range ◽  
Flexible Links ◽  
Beam Elements ◽  
Output Torque ◽  
Manipulator Arm

Abstract Experiments were performed to verify the analytical models for a robotic manipulator with two flexible links. A finite element model (FEM) employing two-dimensional beam elements was used to model the structure. A proportional model relating input voltage to output torque was used for both hub and elbow joint motors. With some minor adjustments to the link stiffness, the FEM modal frequencies matched the experimentally extracted frequencies within 1.5%. However the voltage-torque relationship for the hub motor was found to exhibit dynamics in the frequency range of interest.

Micro/Nano-Tribological Behavior of Octadecyltrichlorosilane on Silicon as a Coating for MEMS

2005 ◽  
Author(s):  
J. Barriga ◽  
B. Ferna´ndez ◽  
E. Abad ◽  
B. Coto
Keyword(s):  
Liquid Phase ◽  
Vapour Phase ◽  
Stick Slip ◽  
Force Microscopy ◽  
Angle Measurements ◽  
Atomic Force ◽  
Contact Angle Measurements ◽  
Assembled Monolayers ◽  
The Coefficient Of Friction ◽  
Semicontact Mode

Despite progresses achieved in the technology of MEMS, the tribological problem continues being an unresolved matter. Wear and stick-slip phenomena are many times the origin of failure of these devices. The application of self-assembled monolayers (SAMs) in liquid phase seems to be a solution to this problems. SAMs of octadecyltrichlorosilane (CH3(CH2)17SiCl3, OTS) were attached to Si(100) oxidized in liquid phase. Contact angle measurements were used for characterizing the grade of hydrophobicity. The topography of the coating was obtained with an Atomic Force Microscopy (AFM) in semicontact mode. The images showed the presence of particles related to the polymerization of the precursor molecule during the formation process of the SAMs. Creating the film of lubricant in vapour phase would avoid this undesirable effect. Tribological tests were carried out with a microtribometer in linear reciprocating movement with a ball of 2 mm of diameter (100Cr6 and Si3N4) and load of some milinewtons. Results were compared with those obtained for silicon oxidized without any coating. The coefficient of friction (COF) and wear (substrate and ball) were studied under different test conditions.

Static Friction Models for Vehicle Simulation Study

2006 ◽  
Author(s):  
Xubin Song ◽  
Daniel G. Smedley
Keyword(s):  
Simulation Study ◽  
Static Friction ◽  
Friction Modeling ◽  
Stick Slip ◽  
Vehicle Simulation ◽  
Engineering Software ◽  
Variable Step ◽  
History Of ◽  
Friction Models ◽  
Smooth Dynamics

The history of the challenge of friction modeling is briefly reviewed. Then this paper focuses on the modeling and simulation study of the friction related dynamics in the Simulink® environment, because Matlab®/Simulink® are popular engineering software tools for both industry and academia. Matlab® and Simulink® are the proprietary products of MathWorks, Inc. In this paper, the static friction models are studied through Simulink® by applying fixed and variable step sizes. The comparison shows that the static Karnopp model is not only numerically tractable but also can be inclusive of the fundamental friction characteristics of both stick slip and correct friction predictions. Finally this paper presents an improved Karnopp model for clutch modeling with the use of Simulink®, and the simulation shows that this model is computationally tractable with smooth dynamics.

Stick-Slip Compensation of Micro-Positioning Using Elastic-Plastic Static Friction Model

2008 ◽  
Vol 47-50 ◽  
pp. 246-249
Author(s):  
Min Gyu Jang ◽  
Chul Hee Lee ◽  
Seung Bok Choi
Keyword(s):  
Static Friction ◽  
Friction Model ◽  
Smart Structure ◽  
Asperity Contact ◽  
Stick Slip ◽  
Elastic Plastic ◽  
Highly Nonlinear ◽  
Bridge Type ◽  
Structural Parts ◽  
Rough Surface Contact

In this paper, a stick-slip compensation for the micro-positioning is presented using the statistical rough surface contact model. As for the micro-positioning structure, PZT (lead(Pb) zirconia(Zr) Titanate(Ti)) actuator is used to drive the load for precise positioning with its high resolution incorporating with the PID (Proportional Integral Derivative) control algorithm. Since the stick-slip characteristics for the micro structures are highly nonlinear and complicated, it is necessary to incorporate more detailed stick-slip model for the applications involving the high precision motion control. Thus, the elastic-plastic static friction model is used for the stick-slip compensation considering the elastic-plastic asperity contact in the rough surfaces statistically. Mathematical model of the system for the positioning apparatus was derived from the dynamic behaviors of structural parts. Since the conventional piezoelectric actuator generates the short stroke, a bridge-type flexural hinge mechanism is introduced to amplify the linear motion range. Using the proposed smart structure, simulations under the representative positioning motion were conducted to demonstrate the micro-positioning under the stick-slip friction.

scholarly journals Experimental Study on the Transition between Static and Kinetic Frictions of Steel/Shale Pairs

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Qin Lian ◽  
Chunxu Yang ◽  
Jifei Cao
Keyword(s):  
Friction Coefficient ◽  
Normal Load ◽  
Critical Distance ◽  
Dynamic Friction ◽  
Stick Slip ◽  
Dynamic Friction Coefficient ◽  
The Coefficient Of Friction ◽  
The Difference ◽  
Stick Slip Motion ◽  
Insight Into

The transition between static and kinetic frictions of steel/shale pairs has been studied. It was found that the coefficient of friction decreased exponentially from static to dynamic friction coefficient with increasing sliding displacement. The difference between static and dynamic friction coefficients and the critical distance Dc under the dry friction condition is much larger than that under the lubricated condition. The transition from static to dynamic friction coefficient is greatly affected by the normal load, quiescent time, and sliding velocity, especially the lubricating condition. Maintaining continuous lubrication of the contact area by the lubricant is crucial to reduce or eliminate the stick-slip motion. The results provide an insight into the transition from static to dynamic friction of steel/shale pairs.

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