3-D Multibody Modeling of a Flexible Surgical Instrument Inside an Endoscope

2012 ◽  
Author(s):  
J. P. Khatait ◽  
D. M. Brouwer ◽  
J. P. Meijaard ◽  
R. G. K. M. Aarts ◽  
J. L. Herder
Keyword(s):  
Interaction Force ◽  
Tangential Direction ◽  
Rotational Behavior ◽  
Surgical Instrument ◽  
Force Transmission ◽  
Multibody Model ◽  
Wall Stiffness ◽  
Set Up ◽  
D Model ◽  
Flexible Instruments

Modern surgical procedures involve flexible instruments for both diagnostic and therapeutic purposes. 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 and clearance inside the endoscope, and the compliance of the instrument. The objective of this paper is to set up a 3-D flexible multibody model for a surgical instrument inside an endoscope to study its translational and rotational behavior. The 3-D model incorporates all the deformations—axial, torsion, and bending—due to its interaction with the surroundings. The interaction due to the contact is defined along the normal and tangential direction at the contact point. The wall stiffness and damping are defined in the normal direction. Friction is defined along the tangential direction. The calculation of the interaction force and moment is explained with an example. Various simulations were performed to study the behavior of the instrument inside a curved rigid tube. The simulations for the insertion into a 3-D tube defined in a plane were compared for both 2-D and 3-D model. The simulation results from the 3-D model give the same results as the 2-D model. A simulation was carried out for the insertion in a 3-D tube using the 3-D model and the total interaction force on the instrument was analyzed. A 3-D multibody model was set up for the simulation offline rotation. A motion hysteresis of 5° was observed for the chosen configuration. The 3-D multibody model is able to demonstrate the characteristic behavior of the flexible instrument under different scenarios. Both translational and rotational behavior of the instrument can be characterized for the given set of parameters. The developed model will help us to study the effect of various parameters on the motion and force transmission of the instrument.

Design of an Experimental Set-Up to Study the Behavior of a Flexible Surgical Instrument Inside an Endoscope

2013 ◽  
Vol 7 (3) ◽  
Author(s):  
Jitendra P. Khatait ◽  
Dannis M. Brouwer ◽  
Herman M. J. R. Soemers ◽  
Ronald G. K. M. Aarts ◽  
Just L. Herder
Keyword(s):  
Modular Design ◽  
Interaction Force ◽  
Surgical Instrument ◽  
Force Transmission ◽  
Multibody Model ◽  
Displacement Sensors ◽  
Flexible Multibody ◽  
Cell Modules ◽  
Set Up

The success of flexible instruments in surgery requires high motion and force fidelity and controllability of the tip. However, the friction and the limited stiffness of such instruments limit the motion and force transmission of the instrument. In a previous study, we developed a flexible multibody model of a surgical instrument inside an endoscope in order to study the effect of the friction, bending and rotational stiffness of the instrument and clearance on the motion hysteresis and the force transmission. In this paper, we present the design and evaluation of an experimental setup for the validation of the flexible multibody model and the characterization of the instruments. A modular design was conceived based on three key functionalities: the actuation from the proximal end, the displacement measurement of the distal end, and the measurement of the interaction force. The exactly constrained actuation module achieves independent translation and rotation of the proximal end. The axial displacement and the rotation of the distal end are measured contactless via a specifically designed air bearing guided cam through laser displacement sensors. The errors in the static measurement are 15 μm in translation and 0.15 deg in rotation. Six 1-DOF load cell modules using flexures measure the interaction forces and moments with an error of 0.8% and 2.5%, respectively. The achieved specifications allow for the measurement of the characteristic behavior of the instrument inside a curved rigid tube and the validation of the flexible multibody model.

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 Direct observation of a coil-to-helix contraction triggered by vinculin binding to talin

2020 ◽  
Vol 6 (21) ◽  
pp. eaaz4707 ◽  
Author(s):  
Rafael Tapia-Rojo ◽  
Alvaro Alonso-Caballero ◽  
Julio M. Fernandez
Keyword(s):  
Focal Adhesions ◽  
Interaction Force ◽  
Magnetic Tweezers ◽  
Feedback Mechanism ◽  
Force Transmission ◽  
Mechanical Coupling ◽  
Negative Feedback Mechanism ◽  
The Reformation ◽  
Energy Penalty ◽  
First Time

Vinculin binds unfolded talin domains in focal adhesions, which recruits actin filaments to reinforce the mechanical coupling of this organelle. However, it remains unknown how this interaction is regulated and its impact on the force transmission properties of this mechanotransduction pathway. Here, we use magnetic tweezers to measure the interaction between vinculin head and the talin R3 domain under physiological forces. For the first time, we resolve individual binding events as a short contraction of the unfolded talin polypeptide caused by the reformation of the vinculin-binding site helices, which dictates a biphasic mechanism that regulates this interaction. Force favors vinculin binding by unfolding talin and exposing the vinculin-binding sites; however, the coil-to-helix contraction introduces an energy penalty that increases with force, defining an optimal binding regime. This mechanism implies that the talin-vinculin-actin association could operate as a negative feedback mechanism to stabilize force on focal adhesions.

Research on the Flow Character of Regenerative Heating Furnace Affected by the Switching Model

2011 ◽  
Vol 383-390 ◽  
pp. 6210-6214
Author(s):  
Kun Can Zheng ◽  
Zhi Wen ◽  
Xun Liang Liu ◽  
Wen Fei Wu ◽  
Xia Lan Huang ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Heating Furnace ◽  
Design And Optimization ◽  
Switching Model ◽  
The Law ◽  
Set Up ◽  
Regenerative Furnace ◽  
D Model

On the basis of wholly analyzing the mechanism of the heat transfer in the 1880 regenerative furnace, the physical and mathematical 3-D model was set up to describe the heat transfer and combustion in the furnace, and the CFD software was used to simulate the whole combusting process in detail. From this, the law of the flow affected by four classical switching modes was studied in emphasis. The conclusions in the study were helpful to the reasonably design and optimization controlling of such furnaces.

Research on Tractor of Coal Mine Horizontal Belt Extension Transfer Machine

2013 ◽  
Vol 791-793 ◽  
pp. 750-753
Author(s):  
Ping Huai Mao ◽  
Bing Zhai ◽  
Jing Xi Li
Keyword(s):  
Coal Mine ◽  
Frame Structure ◽  
Main Function ◽  
Working Process ◽  
Loading Problem ◽  
Use Efficiency ◽  
Set Up ◽  
D Model ◽  
Direct Use ◽  
Machine Structure

Coal mine horizontal belt extension transfer machine is designed in order to solve the mine loading efficiency is not high; especially the most loading mechanical failed to solve continuous loading problem. This machine can also load a whole column tramcars and tramcars without modification with direct use, efficiency improve obviously. This paper first introduces transfer machine structure and working process, and introduces its important part tractor, structure and main function; Then as the main force of tractor parts, we frame for stress analysis, and set up the frame of 3-D model; Finally put the model into ANSYS of its structure statics analysis, and according to the result of analysis frame structure optimization. We will use the same approach to the design of tractor other components, finally complete the complete tractor. Through the study of tractor, summarizes the design methods for other similar mechanical similar provide a theory basis for the design.

Soil - Structure Interaction Effects on the Bridge Isolation System

2011 ◽  
Vol 374-377 ◽  
pp. 2375-2378
Author(s):  
Hai Qing Liu ◽  
Ya Bing Wang
Keyword(s):  
Comparative Analysis ◽  
Soil Structure ◽  
Soil Structure Interaction ◽  
Structural System ◽  
Isolation System ◽  
Structure Interaction ◽  
Rubber Bearing ◽  
Laminated Rubber Bearing ◽  
Set Up ◽  
D Model

Isolation technology has been applied to bridges more than before, and soil-structure interaction on structural system is gradually attracted people's attention, but combine the two is also considered very few especially in the bridge. In this paper, we combine the two cases, and set up 3-D model by ANSYS, do comparative analysis in three cases. The first is no bearing and no soil-structure interaction, the second is with laminated rubber bearing but not considering the soil - structure interaction, and the last one is considering both laminated rubber bearing and soil - structure interaction. Ultimately it proves that soil - structure interaction on the structure does produce effects what can not be ignored.

Optimizing surgical instrument sets for cases involving breast and plastic surgeons.

2016 ◽  
Vol 34 (7_suppl) ◽  
pp. 33-33
Author(s):  
Abigail Suzanne Caudle ◽  
Jason B. Fleming ◽  
Brian M Garcia ◽  
Marina Lozano ◽  
Darryl Rigby ◽  
...  
Keyword(s):  
Cancer Care ◽  
Breast Surgery ◽  
Cost Savings ◽  
High Volume ◽  
Median Number ◽  
Surgical Instrument ◽  
Independent Observer ◽  
Set Up ◽  
Instrument Processing ◽  
Standard Sets

33 Background: Processing operative instrumemt sets is a major cost for surgical cancer care. Optimizing standard sets requires availability of instruments reflecting varied surgeon preferences while minimizing unnecessary instruments. Additionally, increasing utilization of oncoplastic reconstruction after mastectomy and lumpectomy requiring breast and plastic surgery sets further expands the number of instruments required. The goal of our study was to optimize standard sets used for cases combining breast and plastic surgeons and to determine cost savings Methods: Baseline data was recorded over a 2 week period (13 cases) including number of instruments available and number unused for non- flap breast-plastics combo (BPC) cases. An independent observer timed instrument set-up times. 22 breast and 14 plastic surgeons were polled for their requested instruments for designated cases. A BPC set was designed based on this data and reviewed with surgeons to update preference cards. After a 6 week implamentation/education period, repeat data was recorded (18 cases). Cost of instrument processing was based on labor and supply cost of $0.22/instrument. Results: Two breast surgery sets (65 and 97 instruments) and one plastics set ( 93 instruments) were used at baseline. The median number of available instrumeets was 172.5/case, with median 126.5 instruments unused. A mean of 3.8 separately packaged instruments were required per case with mean set-up time of 4m46s. The new BPC set contains 103 instruments. A median of 106.5 instruments were available after implementation. The median number of unused was reduced by 53% to 59.5, with a drop in number of separately processed instruments to 2.5. Mean set-up time was reduced to 2m16s. Reducing the size of of standard sets reduced processing costs by $12.10 or $19.14/case (depending on the breast set used for comparison). Combining sets resulted in an additional cost savings of $6.56/case by reducing extra packaging costs. Conclusions: combining breast and plastic sets and eliminating unnecessary instruments resulted in cost savings of $18.66-$25.70/case. It also reduced OR instrument set-up time by 2.5 minutes/case which has significant impact at high volume centers.

Control of a Helicopter Main Gearbox Active Suspension System

2014 ◽  
Author(s):  
Jonathan Rodriguez ◽  
Luc Gaudiller ◽  
Simon Chesne ◽  
Paul Cranga
Keyword(s):  
Disturbance Rejection ◽  
Control Algorithm ◽  
Narrow Band ◽  
Active Suspension ◽  
Frequency Bandwidth ◽  
Active System ◽  
Multibody Model ◽  
Suspension Systems ◽  
Set Up ◽  
New Generation

This paper considers the control of a helicopter gearbox electromagnetic suspension for a complete multibody model of the structure. As the new generation of helicopters includes variable engine RPM during flight, it becomes relevant to add active control in their suspension systems. Most of active system performances derive directly from the controller construction, its optimization to the system controlled and the disturbances expected. An investigation on a FXLMS control algorithm has been made to optimize it in terms of narrow band disturbance rejection. In this paper an active suspension based on DAVI principle is evaluated. Firstly, a multibody model is set up to estimate realistic acceleration levels inside the cabin. Then multiple controllers are tested, minimizing vibrations on different parts of the helicopter structure. The simulations tend to prove that it is possible to implement an effective active suspension with a low power actuator and obtain a significant vibration reduction level for a frequency bandwidth centered at the natural frequency of the original DAVI.

Study of a Major Mechanism for Self-Loosening of Bolted Joints

2006 ◽  
Author(s):  
Ziqin Wang ◽  
Yanyao Jiang
Keyword(s):  
Contact Pressure ◽  
Three Dimensional ◽  
Bending Moment ◽  
Tangential Direction ◽  
Relative Displacement ◽  
Bolted Joints ◽  
Major Mechanism ◽  
Fe Simulations ◽  
Local Slip ◽  
D Model

A recent three-dimensional (3-D) finite element (FE) investigation on self-loosening of bolted joints revealed that two major mechanisms were responsible for the second-stage (nut rotation) self-loosening of bolted joints. One of the mechanisms is the slip-stick contact of the thread surfaces under the combined contact pressure and reversed bending moment exerted from the reversed transverse loading. The current investigation is a detailed study of the slip-stick contact of the thread surfaces with models that mimic the bolt loading condition. The contact pressure and the reversed bending moment are obtained from an earlier simulation for an M12 bolt. The FE simulations indicate that, with the contact pressure on the thread surface of the bolt and nut, the alternating bending moment results in the gradual motion between the contact thread surfaces. A detailed look at the contact surfaces reveals that localized slip along the tangential direction occurs in part of the contact area and the accumulation of this local slip is responsible for the gradual relative motion between bolt and nut. The FE simulations also indicate that the amplitude of the bending moment greatly influences the relative displacement between the bolt and the nut. There exists a threshold below which local slip will not occur. Results from a two-dimensional (2-D) model are discussed and compared with those obtained from a 3-D model.

Virtual Manipulation of Multi-Wall Carbon Nanotubes with Atomic Force Microscope

2012 ◽  
Vol 263-266 ◽  
pp. 468-471
Author(s):  
Zhan Gao ◽  
Shu You Zhang ◽  
Jie Hua Wang
Keyword(s):  
Carbon Nanotubes ◽  
Atomic Force Microscope ◽  
Interaction Force ◽  
Multi Wall Carbon Nanotubes ◽  
Force Modeling ◽  
Atomic Force ◽  
Current State ◽  
Deformation Simulation ◽  
Set Up ◽  
Vr Simulator

This paper describes a virtual reality (VR) simulator for the manipulation of carbon multi-wall nanotubes with atomic force microscope (AFM). Major challenges in interfacing a human operator with tasks of manipulating nanotubes via a haptic VR interface are outlined. After a review of our previous efforts, we present the current state of our VR simulator for multi-wall nanotube manipulation. The collision detection, interaction force modeling, deformation simulation and haptic rendering of nanotubes are then discussed. Results of virtual manipulation of carbon nanotubes are presented within an immersive VR set-up.

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