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Rainer Bader - One of the best experts on this subject based on the ideXlab platform.
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dynamical analysis of dislocation associated factors in total hip replacements by hardware in the loop simulation
Journal of Orthopaedic Research, 2017Co-Authors: A Geier, Daniel Kluess, R Grawe, Sven Herrmann, Darryl D Dlima, Christoph Woernle, Rainer BaderAbstract:Since dislocation of total hip replacements (THR) remains a clinical problem, its mechanisms are still in the focus of research. Previous studies ignored the impact of soft tissue structures and dynamic processes or relied on simplified joint contact mechanics, thus, hindered a thorough understanding. Therefore, the purpose of the present study was to use hardware-in-the-loop (HiL) simulation to analyze systematically the impact of varying implant positions and designs as well as gluteal and posterior muscle function on THR instability under physiological-like loading conditions during dynamic movements. A musculoskeletal Multibody Model emulated the in situ environment of the lower extremity during deep sit-to-stand with femoral adduction maneuver while a six-axis robot moved and loaded a THR accordingly to feed physical measurements back to the Multibody Model. Commercial THRs with hard-soft bearings were used in the simulation with three different head diameters (28, 36, 44 mm) and two offsets (M, XL). Cup inclination of 45°, cup anteversion of 20°, and stem anteversion of 10° revealed to be outstandingly robust against any instability-related parameter variation. For the flexion motion, higher combined anteversion angles of cup and stem seemed generally favorable. Total hip instability was either deferred or even avoided even in the presence of higher cup inclination. Larger head diameters (>36 mm) and femoral head offsets (8 mm) deferred occurrence of prosthetic and bone impingement associated with increasing resisting torques. In summary, implant positioning had a much higher impact on total hip stability than gluteal insufficiency and impaired muscle function. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:2557-2566, 2017.
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dynamic analysis of dislocation associated factors in total hip replacement by hardware in the loop simulation
Journal of Bone and Joint Surgery-british Volume, 2016Co-Authors: A Geier, Daniel Kluess, R Grawe, Christoph Woernle, Rainer BaderAbstract:Introduction The purpose of this study was to experimentally evaluate impingement and dislocation of total hip replacements while performing dynamic movements under physiological-like conditions. Therefore, a hardware-in-the-loop setup has been developed, in which a physical hip prosthesis actuated by an industrial robot interacts with an in situ-like environment mimicked by a musculoskeletal Multibody simulation-Model of the lower extremity. Methods The Multibody Model of the musculoskeletal system comprised rigid bone segments of the lower right extremity, which were mutually linked by ideal joints, and a trunk. All bone geometries were reconstructed from a computed tomography set preserving anatomical landmarks. Inertia properties were identified based on anthropometric data and by correlating bone density to Hounsfield units. Relevant muscles were Modeled as Hill-type elements, passive forces due to capsular tissue have been neglected. Motion data were captured from a healthy subject performing dislocation-associated movements and were fed to the musculoskeletal Multibody Model. Subsequently, the robot moved and loaded a commercially available total hip prosthesis and closed the loop by feeding the physical contact information back to the simulation Model. In this manner, a comprehensive parameter study analyzing the impact of implant position and design, joint loading, soft tissue damage and bone resection was implemented. Results The parameter study revealed a generally high dislocation risk for the seating-to-rising with adduction scenarios. Improper implant positioning or design could be compensated by adjusting prosthesis components correspondingly. Gluteal insufficiency or lower joint loading did not result in higher impingement or dislocation risk. However, severe malfunction of the artificial joint was found for proximal bone resection. Discussion Previous testing setups ignored the impact of active muscles or relied on simplified contact mechanics. Herein, total hip replacement stability has been investigated experimentally by using a hardware-in-the-loop simulation. Thereby, several influencing factors such as implant position and design as well as soft tissue insufficiency and imbalance could be systematically evaluated with the goal to enhance joint stability.
A Geier - One of the best experts on this subject based on the ideXlab platform.
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dynamical analysis of dislocation associated factors in total hip replacements by hardware in the loop simulation
Journal of Orthopaedic Research, 2017Co-Authors: A Geier, Daniel Kluess, R Grawe, Sven Herrmann, Darryl D Dlima, Christoph Woernle, Rainer BaderAbstract:Since dislocation of total hip replacements (THR) remains a clinical problem, its mechanisms are still in the focus of research. Previous studies ignored the impact of soft tissue structures and dynamic processes or relied on simplified joint contact mechanics, thus, hindered a thorough understanding. Therefore, the purpose of the present study was to use hardware-in-the-loop (HiL) simulation to analyze systematically the impact of varying implant positions and designs as well as gluteal and posterior muscle function on THR instability under physiological-like loading conditions during dynamic movements. A musculoskeletal Multibody Model emulated the in situ environment of the lower extremity during deep sit-to-stand with femoral adduction maneuver while a six-axis robot moved and loaded a THR accordingly to feed physical measurements back to the Multibody Model. Commercial THRs with hard-soft bearings were used in the simulation with three different head diameters (28, 36, 44 mm) and two offsets (M, XL). Cup inclination of 45°, cup anteversion of 20°, and stem anteversion of 10° revealed to be outstandingly robust against any instability-related parameter variation. For the flexion motion, higher combined anteversion angles of cup and stem seemed generally favorable. Total hip instability was either deferred or even avoided even in the presence of higher cup inclination. Larger head diameters (>36 mm) and femoral head offsets (8 mm) deferred occurrence of prosthetic and bone impingement associated with increasing resisting torques. In summary, implant positioning had a much higher impact on total hip stability than gluteal insufficiency and impaired muscle function. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:2557-2566, 2017.
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dynamic analysis of dislocation associated factors in total hip replacement by hardware in the loop simulation
Journal of Bone and Joint Surgery-british Volume, 2016Co-Authors: A Geier, Daniel Kluess, R Grawe, Christoph Woernle, Rainer BaderAbstract:Introduction The purpose of this study was to experimentally evaluate impingement and dislocation of total hip replacements while performing dynamic movements under physiological-like conditions. Therefore, a hardware-in-the-loop setup has been developed, in which a physical hip prosthesis actuated by an industrial robot interacts with an in situ-like environment mimicked by a musculoskeletal Multibody simulation-Model of the lower extremity. Methods The Multibody Model of the musculoskeletal system comprised rigid bone segments of the lower right extremity, which were mutually linked by ideal joints, and a trunk. All bone geometries were reconstructed from a computed tomography set preserving anatomical landmarks. Inertia properties were identified based on anthropometric data and by correlating bone density to Hounsfield units. Relevant muscles were Modeled as Hill-type elements, passive forces due to capsular tissue have been neglected. Motion data were captured from a healthy subject performing dislocation-associated movements and were fed to the musculoskeletal Multibody Model. Subsequently, the robot moved and loaded a commercially available total hip prosthesis and closed the loop by feeding the physical contact information back to the simulation Model. In this manner, a comprehensive parameter study analyzing the impact of implant position and design, joint loading, soft tissue damage and bone resection was implemented. Results The parameter study revealed a generally high dislocation risk for the seating-to-rising with adduction scenarios. Improper implant positioning or design could be compensated by adjusting prosthesis components correspondingly. Gluteal insufficiency or lower joint loading did not result in higher impingement or dislocation risk. However, severe malfunction of the artificial joint was found for proximal bone resection. Discussion Previous testing setups ignored the impact of active muscles or relied on simplified contact mechanics. Herein, total hip replacement stability has been investigated experimentally by using a hardware-in-the-loop simulation. Thereby, several influencing factors such as implant position and design as well as soft tissue insufficiency and imbalance could be systematically evaluated with the goal to enhance joint stability.
Wim Desmet - One of the best experts on this subject based on the ideXlab platform.
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A Discrete-Time Extended Kalman Filter Approach Tailored for Multibody Models: State-Input Estimation
'MDPI AG', 2021Co-Authors: Rocco Adduci, Martijn Vermaut, Frank Naets, Jan Croes, Wim DesmetAbstract:Model-based force estimation is an emerging methodology in the mechatronic community given the possibility to exploit physically inspired high-fidelity Models in tandem with ready-to-use cheap sensors. In this work, an inverse input load identification methodology is presented combining high-fidelity Multibody Models with a Kalman filter-based estimator and providing the means for an accurate and computationally efficient state-input estimation strategy. A particular challenge addressed in this work is the handling of the redundant state-description encountered in common Multibody Model descriptions. A novel linearization framework is proposed on the time-discretized equations in order to extract the required system Model matrices for the Kalman filter. The presented framework is experimentally validated on a slider-crank mechanism. The nonlinear kinematics and dynamics are well represented through a rigid Multibody Model with lumped flexibilities to account for localized interaction phenomena among bodies. The proposed methodology is validated estimating the input torque delivered by a driver electro-motor together with the system states and comparing the experimental data with the estimated quantities. The results show the stability and accuracy of the estimation framework by only employing the angular motor velocity, measured by the motor encoder sensor and available in most of the commercial electro-motors
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Multibody Model based estimation of multiple loads and strain field on a vehicle suspension system
Mechanical Systems and Signal Processing, 2019Co-Authors: Tommaso Tamarozzi, Wim Desmet, Enrico Risaliti, Martijn Vermaut, Bram CornelisAbstract:Abstract This work proposes an augmented extended Kalman filter based state-input estimator for mechanical systems defined by implicit equations of motion which is then applied to estimate the six wheel center loads and the strain field on a vehicle suspension test rig. Implicit equations of motion typically arise in the definition of flexible Multibody Models and also in their time resolution, because implicit time-discretization schemes are normally employed to obtain a stable solution. The presented methodology can be applied to such case and analytical expressions are derived for the necessary linearizations, providing the means for a computationally efficient estimation procedure. The six wheel center loads and the strain field on a vehicle suspension system are valuable quantities during the vehicle design phase (e.g. for durability analysis), hence they are often directly measured during elaborate full vehicle testing campaigns. This work demonstrates that a flexible Multibody Model representation allows to accurately reconstruct the time domain signals of the six loads and of the full strain field, starting from a minimal set of six measured strains, hence providing an appealing alternative to direct measurement methods. The experimental validation on the suspension test rig shows that all estimated quantities can be accurately reconstructed, given that the system simulation Model incorporates an adequate level of accuracy.
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static modes switching in gear contact simulation
Mechanism and Machine Theory, 2013Co-Authors: Tommaso Tamarozzi, Pascal Ziegler, Peter Eberhard, Wim DesmetAbstract:Abstract Contact Modeling is an active research area in the field of Multibody dynamics. Despite the important research effort, two main challenging issues, namely accuracy and speed, are not yet jointly solved. One main issue remains which is the lack of Model order reduction schemes capable to efficiently treat systems where multiple, a priori unknown, input–output locations are present. This work first analyzes the importance of including the necessary residual attachment modes by numerical simulation of two gears meshing in an ad-hoc flexible Multibody Model. Given the large number of residual attachment modes needed, the methodology named static modes switching is extended and successfully applied to improve efficiency. The method proposes an on-line selection of residual attachment modes for accurate local deformation prediction. The applicability to impact problems is discussed through numerical experiments and the automatic selection strategy is based purely on geometrical information. Results show that the method can be applied to gear meshing simulation, obtaining a high level of accuracy while preserving computational efficiency. Comparisons are made between modally reduced Models, full non-linear finite element and the proposed strategy.
Daniel Kluess - One of the best experts on this subject based on the ideXlab platform.
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dynamical analysis of dislocation associated factors in total hip replacements by hardware in the loop simulation
Journal of Orthopaedic Research, 2017Co-Authors: A Geier, Daniel Kluess, R Grawe, Sven Herrmann, Darryl D Dlima, Christoph Woernle, Rainer BaderAbstract:Since dislocation of total hip replacements (THR) remains a clinical problem, its mechanisms are still in the focus of research. Previous studies ignored the impact of soft tissue structures and dynamic processes or relied on simplified joint contact mechanics, thus, hindered a thorough understanding. Therefore, the purpose of the present study was to use hardware-in-the-loop (HiL) simulation to analyze systematically the impact of varying implant positions and designs as well as gluteal and posterior muscle function on THR instability under physiological-like loading conditions during dynamic movements. A musculoskeletal Multibody Model emulated the in situ environment of the lower extremity during deep sit-to-stand with femoral adduction maneuver while a six-axis robot moved and loaded a THR accordingly to feed physical measurements back to the Multibody Model. Commercial THRs with hard-soft bearings were used in the simulation with three different head diameters (28, 36, 44 mm) and two offsets (M, XL). Cup inclination of 45°, cup anteversion of 20°, and stem anteversion of 10° revealed to be outstandingly robust against any instability-related parameter variation. For the flexion motion, higher combined anteversion angles of cup and stem seemed generally favorable. Total hip instability was either deferred or even avoided even in the presence of higher cup inclination. Larger head diameters (>36 mm) and femoral head offsets (8 mm) deferred occurrence of prosthetic and bone impingement associated with increasing resisting torques. In summary, implant positioning had a much higher impact on total hip stability than gluteal insufficiency and impaired muscle function. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:2557-2566, 2017.
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dynamic analysis of dislocation associated factors in total hip replacement by hardware in the loop simulation
Journal of Bone and Joint Surgery-british Volume, 2016Co-Authors: A Geier, Daniel Kluess, R Grawe, Christoph Woernle, Rainer BaderAbstract:Introduction The purpose of this study was to experimentally evaluate impingement and dislocation of total hip replacements while performing dynamic movements under physiological-like conditions. Therefore, a hardware-in-the-loop setup has been developed, in which a physical hip prosthesis actuated by an industrial robot interacts with an in situ-like environment mimicked by a musculoskeletal Multibody simulation-Model of the lower extremity. Methods The Multibody Model of the musculoskeletal system comprised rigid bone segments of the lower right extremity, which were mutually linked by ideal joints, and a trunk. All bone geometries were reconstructed from a computed tomography set preserving anatomical landmarks. Inertia properties were identified based on anthropometric data and by correlating bone density to Hounsfield units. Relevant muscles were Modeled as Hill-type elements, passive forces due to capsular tissue have been neglected. Motion data were captured from a healthy subject performing dislocation-associated movements and were fed to the musculoskeletal Multibody Model. Subsequently, the robot moved and loaded a commercially available total hip prosthesis and closed the loop by feeding the physical contact information back to the simulation Model. In this manner, a comprehensive parameter study analyzing the impact of implant position and design, joint loading, soft tissue damage and bone resection was implemented. Results The parameter study revealed a generally high dislocation risk for the seating-to-rising with adduction scenarios. Improper implant positioning or design could be compensated by adjusting prosthesis components correspondingly. Gluteal insufficiency or lower joint loading did not result in higher impingement or dislocation risk. However, severe malfunction of the artificial joint was found for proximal bone resection. Discussion Previous testing setups ignored the impact of active muscles or relied on simplified contact mechanics. Herein, total hip replacement stability has been investigated experimentally by using a hardware-in-the-loop simulation. Thereby, several influencing factors such as implant position and design as well as soft tissue insufficiency and imbalance could be systematically evaluated with the goal to enhance joint stability.
R Grawe - One of the best experts on this subject based on the ideXlab platform.
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dynamical analysis of dislocation associated factors in total hip replacements by hardware in the loop simulation
Journal of Orthopaedic Research, 2017Co-Authors: A Geier, Daniel Kluess, R Grawe, Sven Herrmann, Darryl D Dlima, Christoph Woernle, Rainer BaderAbstract:Since dislocation of total hip replacements (THR) remains a clinical problem, its mechanisms are still in the focus of research. Previous studies ignored the impact of soft tissue structures and dynamic processes or relied on simplified joint contact mechanics, thus, hindered a thorough understanding. Therefore, the purpose of the present study was to use hardware-in-the-loop (HiL) simulation to analyze systematically the impact of varying implant positions and designs as well as gluteal and posterior muscle function on THR instability under physiological-like loading conditions during dynamic movements. A musculoskeletal Multibody Model emulated the in situ environment of the lower extremity during deep sit-to-stand with femoral adduction maneuver while a six-axis robot moved and loaded a THR accordingly to feed physical measurements back to the Multibody Model. Commercial THRs with hard-soft bearings were used in the simulation with three different head diameters (28, 36, 44 mm) and two offsets (M, XL). Cup inclination of 45°, cup anteversion of 20°, and stem anteversion of 10° revealed to be outstandingly robust against any instability-related parameter variation. For the flexion motion, higher combined anteversion angles of cup and stem seemed generally favorable. Total hip instability was either deferred or even avoided even in the presence of higher cup inclination. Larger head diameters (>36 mm) and femoral head offsets (8 mm) deferred occurrence of prosthetic and bone impingement associated with increasing resisting torques. In summary, implant positioning had a much higher impact on total hip stability than gluteal insufficiency and impaired muscle function. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:2557-2566, 2017.
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dynamic analysis of dislocation associated factors in total hip replacement by hardware in the loop simulation
Journal of Bone and Joint Surgery-british Volume, 2016Co-Authors: A Geier, Daniel Kluess, R Grawe, Christoph Woernle, Rainer BaderAbstract:Introduction The purpose of this study was to experimentally evaluate impingement and dislocation of total hip replacements while performing dynamic movements under physiological-like conditions. Therefore, a hardware-in-the-loop setup has been developed, in which a physical hip prosthesis actuated by an industrial robot interacts with an in situ-like environment mimicked by a musculoskeletal Multibody simulation-Model of the lower extremity. Methods The Multibody Model of the musculoskeletal system comprised rigid bone segments of the lower right extremity, which were mutually linked by ideal joints, and a trunk. All bone geometries were reconstructed from a computed tomography set preserving anatomical landmarks. Inertia properties were identified based on anthropometric data and by correlating bone density to Hounsfield units. Relevant muscles were Modeled as Hill-type elements, passive forces due to capsular tissue have been neglected. Motion data were captured from a healthy subject performing dislocation-associated movements and were fed to the musculoskeletal Multibody Model. Subsequently, the robot moved and loaded a commercially available total hip prosthesis and closed the loop by feeding the physical contact information back to the simulation Model. In this manner, a comprehensive parameter study analyzing the impact of implant position and design, joint loading, soft tissue damage and bone resection was implemented. Results The parameter study revealed a generally high dislocation risk for the seating-to-rising with adduction scenarios. Improper implant positioning or design could be compensated by adjusting prosthesis components correspondingly. Gluteal insufficiency or lower joint loading did not result in higher impingement or dislocation risk. However, severe malfunction of the artificial joint was found for proximal bone resection. Discussion Previous testing setups ignored the impact of active muscles or relied on simplified contact mechanics. Herein, total hip replacement stability has been investigated experimentally by using a hardware-in-the-loop simulation. Thereby, several influencing factors such as implant position and design as well as soft tissue insufficiency and imbalance could be systematically evaluated with the goal to enhance joint stability.