Computational Modeling of a Dynamic Knee Simulator for Reproduction of Joint Loading

2003 ◽  
Author(s):  
Trent M. Guess ◽  
Lorin P. Maletsky
Keyword(s):  
Computational Modeling ◽  
Computational Model ◽  
Three Dimensional ◽  
Joint Loading ◽  
Knee Simulator ◽  
Joint Forces ◽  
Five Axis ◽  
Five Axes

A three-dimensional dynamic computational model was developed for the dual purposes of predicting and replicating joint loading generated by a five-axis dynamic knee simulator. The model was verified through an analog knee that was constrained for accurate modeling and instrumented to directly measure joint forces. The verified model was then used to generate control profiles to the five axes of the simulator for replication of desired joint loading. Reproduction of a walking profile is demonstrated.

Computational Modeling of a Dynamic Knee Simulator for Reproduction of Knee Loading

2005 ◽  
Vol 127 (7) ◽  
pp. 1216-1221 ◽  
Author(s):  
Trent M. Guess ◽  
Lorin P. Maletsky
Keyword(s):  
Computational Modeling ◽  
Computational Model ◽  
Sagittal Plane ◽  
Three Dimensional ◽  
Joint Loading ◽  
Load Prediction ◽  
Prosthetic Knee ◽  
Knee Simulator ◽  
Knee Loading ◽  
Future Work

As a first step towards reproducing desired three-dimensional joint loading and motion on a dynamic knee simulator, the goal of this study was to develop and verify a three-dimensional computational model that generated control profiles for the simulator using desired knee loading and motion as model inputs. The developed model was verified by predicting tibio-femoral loading on an instrumented analog knee for given actuator forces and the ability to generate simulator control profiles was demonstrated using a three-dimensional walking profile. The model predicted axial tibia loading for a sagittal-plane dual-limb squat within 1% of measured peak loading. Adding out-of-sagittal-plane forces decreased the accuracy of load prediction. The model generated control profiles to the simulator that produced axial tibia loading within 16% of desired for walking. Discrepancies in predicted and measured quadriceps forces influenced the accuracy of the generated control profiles. Future work will replace the analog knee in both the model and machine with a prosthetic knee.

Three-Dimensional Knee Joint Loading in Alpine Skiing: A Comparison Between a Carved and a Skidded Turn

2012 ◽  
Vol 28 (6) ◽  
pp. 655-664 ◽  
Author(s):  
Miriam Klous ◽  
Erich Müller ◽  
Hermann Schwameder
Keyword(s):  
Knee Joint ◽  
Inverse Dynamics ◽  
Small Sample Size ◽  
Three Dimensional ◽  
Small Sample ◽  
High Rate ◽  
Joint Loading ◽  
Joint Forces ◽  
Inverse Dynamics Analysis ◽  
Knee Joint Loading

Limited data exists on knee biomechanics in alpine ski turns despite the high rate of injuries associated with this maneuver. The purpose of the current study was to compare knee joint loading between a carved and a skidded ski turn and between the inner and outer leg. Kinetic data were collected using Kistler mobile force plates. Kinematic data were collected with five synchronized, panning, tilting, and zooming cameras. Inertial properties of the segments were calculated using an extended version of the Yeadon model. Knee joint forces and moments were calculated using inverse dynamics analysis. The obtained results indicate that knee joint loading in carving is not consistently greater than knee joint loading in skidding. In addition, knee joint loading at the outer leg is not always greater than at the inner leg. Differentiation is required between forces and moments, the direction of the forces and moments, and the phase of the turn that is considered. Even though the authors believe that the analyzed turns are representative, results have to be interpreted with caution due to the small sample size.

scholarly journals Three-Dimensional Lower Extremity Joint Loading in a Carved Ski and Snowboard Turn: A Pilot Study

2014 ◽  
Vol 2014 ◽  
pp. 1-13 ◽  
Author(s):  
Miriam Klous ◽  
Erich Müller ◽  
Hermann Schwameder
Keyword(s):  
Knee Joint ◽  
Lower Extremity ◽  
Kinetic Data ◽  
Three Dimensional ◽  
Longitudinal Axis ◽  
Joint Loading ◽  
Inverse Dynamic ◽  
Kinematic Data ◽  
Joint Forces ◽  
Anterior Posterior

A large number of injuries to the lower extremity occur in skiing and snowboarding. Due to the difficulty of collecting 3D kinematic and kinetic data with high accuracy, a possible relationship between injury statistic and joint loading has not been studied. Therefore, the purpose of the current study was to compare ankle and knee joint loading at the steering leg between carved ski and snowboard turns. Kinetic data were collected using mobile force plates mounted under the toe and heel part of the binding on skies or snowboard (KISTLER). Kinematic data were collected with five synchronized, panning, tilting, and zooming cameras. An extended version of the Yeadon model was applied to calculate inertial properties of the segments. Ankle and knee joint forces and moments were calculated using inverse dynamic analysis. Results showed higher forces along the longitudinal axis in skiing and similar forces for skiing and snowboarding in anterior-posterior and mediolateral direction. Joint moments were consistently greater during a snowboard turn, but more fluctuations were observed in skiing. Hence, when comparing joint loading between carved ski and snowboard turns, one should differentiate between forces and moments, including the direction of forces and moments and the turn phase.

Computational Modeling of Finger Swipe Gestures on Touchscreen

2016 ◽  
Vol 60 (1) ◽  
pp. 1721-1725 ◽  
Author(s):  
Heejin Jeong ◽  
Yili Liu
Keyword(s):  
Computational Modeling ◽  
Computational Model ◽  
Human Subject ◽  
Movement Time ◽  
Cognitive Architecture ◽  
Three Dimensional ◽  
Finger Movement ◽  
Queuing Network ◽  
3D Space ◽  
Model Human Processor

Although swiping (also called flicking) is one of the commonly used touchscreen gestures, few modeling studies have been conducted. In this paper, a computational model that focuses on touchscreen swipe gestures was developed by extending the QN-MHP (Queuing Network-Model Human Processor) architecture. The model assumed that the swiped-route follows a three-dimensional path. To model the finger swipe gesture, an operator (i.e., “ Swipe-with-finger”) for the Queuing Network Cognitive Architecture was developed using an existing regression equation for predicting the finger movement time in 3D space (Cha and Myung, 2013). The model was validated with two corresponding experimental results in the literature. As a result, the swiping times generated by the model were well fit with the human subject data.

The new CM-Series TEMs: integration of a five-axis motorized, fully computer-controlled goniometer

1993 ◽  
Vol 51 ◽  
pp. 258-259
Author(s):  
Marc J.C. de Jong ◽  
P. Emile S.J. Asselbergs ◽  
Max T. Otten
Keyword(s):  
Mechanical Design ◽  
Computer Control ◽  
Objective Lens ◽  
Access Port ◽  
Vibration Stability ◽  
Transmission Electron ◽  
Computer Controlled ◽  
High Degree ◽  
Five Axis ◽  
Five Axes

A new step forward in Transmission Electron Microscopy has been made with the introduction of the CompuStage on the CM-series TEMs: CM120, CM200, CM200 FEG and CM300. This new goniometer has motorization on five axes (X, Y, Z, α, β), all under full computer control by a dedicated microprocessor that is in communication with the main CM processor. Positions on all five axes are read out directly - not via a system counting motor revolutions - thereby providing a high degree of accuracy. The CompuStage enters the octagonal block around the specimen through a single port, allowing the specimen stage to float freely in the vacuum between the objective-lens pole pieces, thereby improving vibration stability and freeing up one access port. Improvements in the mechanical design ensure higher stability with regard to vibration and drift. During stage movement the holder O-ring no longer slides, providing higher drift stability and positioning accuracy as well as better vacuum.

scholarly journals The five axes of the Turtle: symmetry and asymmetry in NGC 6210

2021 ◽  
Author(s):  
William J Henney ◽  
J A López ◽  
Ma T García-Díaz ◽  
M G Richer
Keyword(s):  
Planetary Nebula ◽  
Morphological Study ◽  
Three Dimensional ◽  
Dimensional Structure ◽  
Line Of Sight ◽  
Velocity Mapping ◽  
High Ionization ◽  
Motion Measurements ◽  
Five Axes ◽  
Triple Star

Abstract We carry out a comprehensive kinematic and morphological study of the asymmetrical planetary nebula: NGC 6210, known as the Turtle. The nebula’s spectacularly chaotic appearance has led to proposals that it was shaped by mass transfer in a triple star system. We study the three-dimensional structure and kinematics of its shells, lobes, knots, and haloes by combining radial velocity mapping from multiple long-slit spectra with proper motion measurements from multi-epoch imaging. We find that the nebula has five distinct ejection axes. The first is the axis of the bipolar, wind-blown inner shell, while the second is the axis of the lop-sided, elliptical, fainter, but more massive intermediate shell. A further two axes are bipolar flows that form the point symmetric, high-ionization outer lobes, all with inclinations close to the plane of the sky. The final axis, which is inclined close to the line of sight, traces collimated outflows of low-ionization knots. We detect major changes in outflow directions during the planetary nebula phase, starting at or before the initial ionization of the nebula 3500 years ago. Most notably, the majority of redshifted low-ionization knots have kinematic ages greater than 2000 years, whereas the majority of blueshifted knots have ages younger than 2000 years. Such a sudden and permanent 180-degree flip in the ejection axis at a relatively late stage in the nebular evolution is a challenge to models of planetary nebula formation and shaping.

scholarly journals How Computational Modeling Can Force Theory Building in Psychological Science

2021 ◽  
pp. 174569162097058
Author(s):  
Olivia Guest ◽  
Andrea E. Martin
Keyword(s):  
Computational Modeling ◽  
Computational Model ◽  
Process Modeling ◽  
Theory Building ◽  
Formal Modeling ◽  
Inference Process ◽  
Experimental Practice ◽  
Psychological Science ◽  
Scientific Inference ◽  
And Behaviors

Psychology endeavors to develop theories of human capacities and behaviors on the basis of a variety of methodologies and dependent measures. We argue that one of the most divisive factors in psychological science is whether researchers choose to use computational modeling of theories (over and above data) during the scientific-inference process. Modeling is undervalued yet holds promise for advancing psychological science. The inherent demands of computational modeling guide us toward better science by forcing us to conceptually analyze, specify, and formalize intuitions that otherwise remain unexamined—what we dub open theory. Constraining our inference process through modeling enables us to build explanatory and predictive theories. Here, we present scientific inference in psychology as a path function in which each step shapes the next. Computational modeling can constrain these steps, thus advancing scientific inference over and above the stewardship of experimental practice (e.g., preregistration). If psychology continues to eschew computational modeling, we predict more replicability crises and persistent failure at coherent theory building. This is because without formal modeling we lack open and transparent theorizing. We also explain how to formalize, specify, and implement a computational model, emphasizing that the advantages of modeling can be achieved by anyone with benefit to all.

A Computational Analysis of Flow Field in Twin-Track Subway Tunnel to Improve Air Quality

2013 ◽  
Vol 319 ◽  
pp. 599-604
Author(s):  
Makhsuda Juraeva ◽  
Kyung Jin Ryu ◽  
Sang Hyun Jeong ◽  
Dong Joo Song
Keyword(s):  
Air Quality ◽  
Computational Model ◽  
Stokes Equations ◽  
Ventilation System ◽  
Three Dimensional ◽  
Aerodynamic Characteristics ◽  
Navier Stokes ◽  
Subway Tunnel ◽  
Air Supply ◽  
And Performance

A computational model of existing Seoul subway tunnelwas analyzed in this research. The computational model was comprised of one natural ventilationshaft, two mechanical ventilationshafts, one mechanical airsupply, a twin-track tunnel, and a train. Understanding the flow pattern of the train-induced airflow in the tunnel was necessary to improve ventilation performance. The research objective wasto improve the air quality in the tunnel by investigating train-induced airflow in the twin-track subway tunnel numerically. The numerical analysis characterized the aerodynamic behavior and performance of the ventilation system by solving three-dimensional turbulent Reynolds-averaged Navier-Stokes equations. ANSYS CFX software was used for the computations. The ventilation and aerodynamic characteristics in the tunnel were investigated by analyzing the mass flowrateat the exits of the ventilation mechanicalshafts. As the train passed the mechanical ventilation shafts, the amount of discharged-air in the ventilationshafts decreased rapidly. The air at the exits of the ventilation shafts was gradually recovered with time, after the train passed the ventilation shafts. The developed mechanical air-supply for discharging dusty air and supplying clean airwas investigated.The computational results showed that the developed mechanical air-supplycould improve the air quality in the tunnel.

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