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Articles 1 - 30 of 305
Full-Text Articles in Mechanical Engineering
Introduction To Data-Driven Systems For Plastics And Composites Manufacturing, Saeed Farahani, Srikanth Pilla, Yun Zhang, Fausto Tucci
Introduction To Data-Driven Systems For Plastics And Composites Manufacturing, Saeed Farahani, Srikanth Pilla, Yun Zhang, Fausto Tucci
Mechanical Engineering Faculty Publications
Applications of high-performance plastics and composites have widely been expanded to various industries due to their superior properties, such as high strength-to-weight ratio, chemical resistance, and thermal/electrical insulation. However, the numerous possible combinations of polymers and reinforcements/fillers, the variability of these materials, and their complex manufacturing processes pose challenges in terms of efficiently developing new plastics and composites, accurately modeling their properties, and effectively monitoring and controlling their manufacturing processes. Integrating data-driven techniques, such as machine learning, artificial intelligence, and big data analytics, is a promising pathway to overcome these challenges as it is demonstrated by the state-of-the-art research works …
Hybrid Fes-Exoskeleton Control: Using Mpc To Distribute Actuation For Elbow And Wrist Movements, Nathan Dunkelberger, Jeffrey Berning, Eric M. Schearer, Marcia K. O'Malley
Hybrid Fes-Exoskeleton Control: Using Mpc To Distribute Actuation For Elbow And Wrist Movements, Nathan Dunkelberger, Jeffrey Berning, Eric M. Schearer, Marcia K. O'Malley
Mechanical Engineering Faculty Publications
Introduction: Individuals who have suffered a cervical spinal cord injury prioritize the recovery of upper limb function for completing activities of daily living. Hybrid FES-exoskeleton systems have the potential to assist this population by providing a portable, powered, and wearable device; however, realization of this combination of technologies has been challenging. In particular, it has been difficult to show generalizability across motions, and to define optimal distribution of actuation, given the complex nature of the combined dynamic system. Methods: In this paper, we present a hybrid controller using a model predictive control (MPC) formulation that combines the actuation of both …
Coaxial Jets With Disparate Viscosity: Mixing And Laminarization Characteristics, Mustafa Usta, M. R. C. Ahmad, G. Pathikonda, I. Khan, P. Gillis, D. Ranjan, C. K. Aidun
Coaxial Jets With Disparate Viscosity: Mixing And Laminarization Characteristics, Mustafa Usta, M. R. C. Ahmad, G. Pathikonda, I. Khan, P. Gillis, D. Ranjan, C. K. Aidun
Mechanical Engineering Faculty Publications
Mixing of fluids in a coaxial jet is studied under four distinct viscosity ratios, m = 1, 10, 20 and 40, using highly resolved large-eddy simulations (LES), particle image velocimetry and planar laser-induced fluorescence. The accuracy of predictions is tested against data obtained by the simultaneous experimental measurements of velocity and concentration fields. For the highest and lowest viscosity ratios, standard RANS models with unclosed terms pertaining to viscosity variations are employed. We show that the standard Reynolds-averaged Navier-Stokes (RANS) approach with no explicit modelling for variable-viscosity terms is not applicable whereas dynamic LES models provide high-quality agreement with the …
Data-Driven Dynamic Motion Planning For Practical Fes-Controlled Reaching Motions In Spinal Cord Injury, Derek N.N. Wolf, Antonie J. Van Den Bogert, Eric M. Schearer
Data-Driven Dynamic Motion Planning For Practical Fes-Controlled Reaching Motions In Spinal Cord Injury, Derek N.N. Wolf, Antonie J. Van Den Bogert, Eric M. Schearer
Mechanical Engineering Faculty Publications
Functional electrical stimulation (FES) is a promising technology for restoring reaching motions to individuals with upper-limb paralysis caused by a spinal cord injury (SCI). However, the limited muscle capabilities of an individual with SCI have made achieving FES-driven reaching difficult. We developed a novel trajectory optimization method that used experimentally measured muscle capability data to find feasible reaching trajectories. In a simulation based on a real-life individual with SCI, we compared our method to attempting to follow naive direct-to-target paths. We tested our trajectory planner with three control structures that are commonly used in applied FES: feedback, feedforward-feedback, and model …
Predictions Of Indentation Stiffness Of Musculoskeletal Regions Using Ultrasound, Sean Doherty
Predictions Of Indentation Stiffness Of Musculoskeletal Regions Using Ultrasound, Sean Doherty
ETD Archive
Tissue indentation response is an important metric for understanding how different musculoskeletal regions respond to loading and is a function of the tissue’s form. Modem imaging techniques provide information about the internal structures of human tissue. Ultrasound remains one of the most common imaging techniques performed, given its portability and low costs. Prior work and data collection on 100 patients involved the collection of ultrasound images at eight different locations across the musculoskeletal extremities. Given the tissue structure information that the medical imaging provided, it was hypothesized that the mechanical properties of the tissue could be predicted from this data. …
Strengthening Effects Of Carbon Nanotubes And Graphene Nanoplatelets Reinforced Nickel Metal Matrix Composites, Amit Patil
ETD Archive
Carbon nanotubes (CNTs) and graphene nanoplatelets (GNPs) with superior mechanical, thermal, chemical, and electrical properties are appealing reinforcements for the fabrication of lightweight, high-strength, and wear-resistant metal matrix composites with outstanding mechanical and tribological performance. The nickel-carbon nanotube composites (Ni-CNT) and nickel-graphene nano-platelet composites (Ni-GNP) were processed using two separate ball milling methods, namely dry ball milling (DM) and solution ball milling (SBM), and then sintered using the spark plasma sintering (SPS) technique. The influence of the premixing process, milling time, reinforcement morphology, and concentration on matrix grain size, microstructure, dispersion in the nickel matrix, mechanical properties, and tribological performance …
3d-Printed Piezoelectric Porous Bioactive Scaffolds And Clinical Ultrasonic Stimulation Can Help In Enhanced Bone Regeneration, Prabaha Sikder, Phaniteja Nagaraju, Harsha P.S. Naganaboyina
3d-Printed Piezoelectric Porous Bioactive Scaffolds And Clinical Ultrasonic Stimulation Can Help In Enhanced Bone Regeneration, Prabaha Sikder, Phaniteja Nagaraju, Harsha P.S. Naganaboyina
Mechanical Engineering Faculty Publications
This paper presents a comprehensive effort to develop and analyze first-of-its-kind design-specific and bioactive piezoelectric scaffolds for treating orthopedic defects. The study has three major highlights. First, this is one of the first studies that utilize extrusion-based 3D printing to develop design-specific macroporous piezoelectric scaffolds for treating bone defects. The scaffolds with controlled pore size and architecture were synthesized based on unique composite formulations containing polycaprolactone (PCL) and micron-sized barium titanate (BaTiO3) particles. Second, the bioactive PCL-BaTiO3 piezoelectric composite formulations were explicitly developed in the form of uniform diameter filaments, which served as feedstock material for the fused filament fabrication …
Mechanistic Understanding Of Phase Stability, Transformation, And Strengthening Mechanisms In Lightweight High Entropy Alloys And High Entropy Ceramics, Ganesh Walunj
ETD Archive
High-entropy alloys (HEAs) are a novel family of solid-solution alloys that have gained international interest due to their exceptional characteristics. Because of the need from the transportation and defense sectors, lightweight HEAs have attracted researcher’s curiosity as prospective advanced materials. Low-weight high entropy alloy synthesizes using arc melting with a mass ratio of AlCrFeMnTix(0.1,0.15,0.2). The synthesized HEA is comprised of a mixture of body center cubic (bcc) and ordered bcc (L21) solid solution phases. The synthesized HEAs have heat treated at 650C, 800C, and 1150C for 1hr, 4hr after solutionized at 1150C for 2 hr to understand the effect of …
Estimation Of Joint Moments During Turning Maneuvers In Alpine Skiing Using A Three Dimensional Musculoskeletal Skier Model And A Forward Dynamics Optimization Framework, Dieter Heinrich, Antonie J. Van Den Bogert, Werner Nachbauer
Estimation Of Joint Moments During Turning Maneuvers In Alpine Skiing Using A Three Dimensional Musculoskeletal Skier Model And A Forward Dynamics Optimization Framework, Dieter Heinrich, Antonie J. Van Den Bogert, Werner Nachbauer
Mechanical Engineering Faculty Publications
In alpine skiing, estimation of the joint moments acting onto the skier is essential to quantify the loading of the skier during turning maneuvers. In the present study, a novel forward dynamics optimization framework is presented to estimate the joint moments acting onto the skier incorporating a three dimensional musculoskeletal model (53 kinematic degrees of freedom, 94 muscles). Kinematic data of a professional skier performing a turning maneuver were captured and used as input data to the optimization framework. In the optimization framework, the musculoskeletal model of the skier was applied to track the experimental data of a skier and …
Mechanistic Undrestanding Of Amorphization In Iron-Based Soft Magnetic Materials, Taban Larimian
Mechanistic Undrestanding Of Amorphization In Iron-Based Soft Magnetic Materials, Taban Larimian
ETD Archive
Iron-based magnetic alloys possess very good magnetic and mechanical properties. Among these alloys Fe-Si-B-based alloys show outstanding saturation magnetization and coercivity which makes them great candidates for many industrial applications. Addition of certain elements to the Fe-Si-B base is proven to improve the homogeneity and fineness of microstructure as well as enhance the magnetic behavior of these alloys. In this research work, we have studied the effect of adding copper and niobium to the Fe-Si-B base alloy. Previous studies have shown that magnetic alloys show better magnetic properties when their microstructure consists of nanocrystals embedded in an amorphous matrix. In …
Viability And Accessibility Of Urban Heat Island And Lake Microclimate Data Over Current Tmy Weather Data For Accurate Energy Demand Predictions., Irena A. Weclawiak
Viability And Accessibility Of Urban Heat Island And Lake Microclimate Data Over Current Tmy Weather Data For Accurate Energy Demand Predictions., Irena A. Weclawiak
ETD Archive
Building Energy Simulations (BES) are necessary for designing energy-efficient systems. Open-source simulation software developed by the Department of Energy (DOE), EnergyPlus (EP) provides Typical Meteorological Year (TMY) weather data that consists of a 15-year average. Two major concerns about this data are the inability to detect extreme conditions and limited data locations. There is a greater number of Microclimate (MC) stations that can be used for simulations, but it involves time-consuming data preparation to match the EP format. This study investigated the effects of Urban Heat Island (UHI) and the MC of Lake Erie. A comparison of the MC data …
An Evaluation And Economic Analysis Of A Water Main Geothermal System In A Residential Space, Brian L. Kohut
An Evaluation And Economic Analysis Of A Water Main Geothermal System In A Residential Space, Brian L. Kohut
ETD Archive
Iron-based magnetic alloys possess very good magnetic and mechanical properties. Among these alloys Fe-Si-B-based alloys show outstanding saturation magnetization and coercivity which makes them great candidates for many industrial applications. Addition of certain elements to the Fe-Si-B base is proven to improve the homogeneity and fineness of microstructure as well as enhance the magnetic behavior of these alloys. In this research work, we have studied the effect of adding copper and niobium to the Fe-Si-B base alloy. Previous studies have shown that magnetic alloys show better magnetic properties when their microstructure consists of nanocrystals embedded in an amorphous matrix. In …
Antagonistic Co-Contraction Can Minimize Muscular Effort In Systems With Uncertainty, Anne D. Koelewijn, Antonie J. Van Den Bogert
Antagonistic Co-Contraction Can Minimize Muscular Effort In Systems With Uncertainty, Anne D. Koelewijn, Antonie J. Van Den Bogert
Mechanical Engineering Faculty Publications
Muscular co-contraction of antagonistic muscle pairs is often observed in human movement, but it is considered inefficient and it can currently not be predicted in
simulations where muscular effort or metabolic energy are minimized. Here, we investigated the relationship between minimizing effort and muscular co-contraction
in systems with random uncertainty to see if muscular co-contraction can minimize effort in such system. We also investigated the effect of time delay in the muscle, by varying the time delay in the neural control as well as the activation time constant.We solved optimal control problems for a one-degree-of-freedom pendulum actuated by two identical …
A Model-Based Approach To Predict Neuromuscular Control Patterns That Minimize Acl Forces During Jump Landing, Dieter Heinrich, Antonie J. Van Den Bogert, Robert Csapo, Werner Nachbauer
A Model-Based Approach To Predict Neuromuscular Control Patterns That Minimize Acl Forces During Jump Landing, Dieter Heinrich, Antonie J. Van Den Bogert, Robert Csapo, Werner Nachbauer
Mechanical Engineering Faculty Publications
Jump landing is a common situation leading to knee injuries involving the anterior cruciate ligament (ACL) in sports. Although neuromuscular control is considered as a key injury risk factor, there is a lack of knowledge regarding optimum control strategies that reduce ACL forces during jump landing. In the present study, a musculoskeletal model-based computational approach
is presented that allows identifying neuromuscular control patterns that minimize ACL forces during jump landing. The approach is demonstrated for a jump landing maneuver in downhill skiing, which is one out of three main injury mechanisms in competitive skiing.
Efficient Trajectory Optimization For Curved Running Using A 3d Musculoskeletal Model With Implicit Dynamics, Marlies Nitschke, Eva Dorschky, Dieter Heinrich, Heiko Schlarb, Bjoern M. Eskofier, Anne D. Koelewijn, Antonie J. Van Den Bogert
Efficient Trajectory Optimization For Curved Running Using A 3d Musculoskeletal Model With Implicit Dynamics, Marlies Nitschke, Eva Dorschky, Dieter Heinrich, Heiko Schlarb, Bjoern M. Eskofier, Anne D. Koelewijn, Antonie J. Van Den Bogert
Mechanical Engineering Faculty Publications
Trajectory optimization with musculoskeletal models can be used to reconstruct measured movements and to predict changes in movements in response to environmental changes. It enables an exhaustive analysis of joint angles, joint moments, ground reaction forces, and muscle forces, among others. However, its application is still limited to simplified problems in two dimensional space or straight motions. The simulation of movements with directional changes, e.g. curved running, requires detailed three dimensional models which lead to a high-dimensional solution space. We
extended a full-body three dimensional musculoskeletal model to be specialized for running with directional changes. Model dynamics were implemented implicitly …
Achieving Practical Functional Electrical Stimulation-Driven Reaching Motions In An Individual With Tetraplegia, Derek Nathaniel Wolf
Achieving Practical Functional Electrical Stimulation-Driven Reaching Motions In An Individual With Tetraplegia, Derek Nathaniel Wolf
ETD Archive
Functional electrical stimulation (FES) is a promising technique for restoring the ability to complete reaching motions to individuals with tetraplegia due to a spinal cord injury (SCI). FES has proven to be a successful technique for controlling many functional tasks such as grasping, standing, and even limited walking. However, translating these successes to reaching motions has proven difficult due to the complexity of the arm and the goaldirected nature of reaching motions. The state-of-the-art systems either use robots to assist the FES-driven reaching motions or control the arm of healthy subjects to complete planar motions. These controllers do not directly …
Cnn-Based Estimation Of Sagittal Plane Walking And Running Biomechanics From Measured And Simulated Inertial Sensor Data, Eva Dorschky, Marlies Nitschke, Christine F. Martindale, Antonie J. Van Den Bogert, Anne D. Koelewijn, Bjoern M. Eskofier
Cnn-Based Estimation Of Sagittal Plane Walking And Running Biomechanics From Measured And Simulated Inertial Sensor Data, Eva Dorschky, Marlies Nitschke, Christine F. Martindale, Antonie J. Van Den Bogert, Anne D. Koelewijn, Bjoern M. Eskofier
Mechanical Engineering Faculty Publications
Machine learning is a promising approach to evaluate human movement based on wearable sensor data. A representative dataset for training data-driven models is crucial to ensure that the model generalizes well to unseen data. However, the acquisition of sufficient data is time-consuming and often infeasible. We present a method to create realistic inertial sensor data with corresponding biomechanical variables by 2D walking and running simulations. We augmented a measured inertial sensor dataset with simulated data for the training of convolutional neural networks to estimate sagittal plane joint angles, joint moments, and ground reaction forces (GRFs) of walking and running. When …
An Extensive Set Of Kinematic And Kinetic Data For Individuals With Intact Limbs And Transfemoral Prosthesis Users, Seyed Abolfazl Fakoorian, Arash Roshanineshat, Poya Khalaf, Vahid Azimi, Daniel J. Simon, Elizabeth Hardin
An Extensive Set Of Kinematic And Kinetic Data For Individuals With Intact Limbs And Transfemoral Prosthesis Users, Seyed Abolfazl Fakoorian, Arash Roshanineshat, Poya Khalaf, Vahid Azimi, Daniel J. Simon, Elizabeth Hardin
Electrical and Computer Engineering Faculty Publications
This paper introduces an extensive human motion data set for typical activities of daily living. These data are crucial for the design and control of prosthetic devices for transfemoral prosthesis users. This data set was collected from seven individuals, including five individuals with intact limbs and two transfemoral prosthesis users. These data include the following types of movements: (1) walking at three different speeds; (2) walking up and down a 5-degree ramp; (3) stepping up and down; (4) sitting down and standing up. We provide full-body marker trajectories and ground reaction forces (GRFs) as well as joint angles, joint velocities, …
Estimation Of Gait Kinematics And Kinetics From Inertial Sensor Data Using Optimal Control Of Musculoskeletal Models, Eva Dorschky, Marlies Nitschke, Ann-Kristin Seifer, Antonie J. Van Den Bogert, Bjoern M. Eskofier
Estimation Of Gait Kinematics And Kinetics From Inertial Sensor Data Using Optimal Control Of Musculoskeletal Models, Eva Dorschky, Marlies Nitschke, Ann-Kristin Seifer, Antonie J. Van Den Bogert, Bjoern M. Eskofier
Mechanical Engineering Faculty Publications
Inertial sensing enables field studies of human movement and ambulant assessment of patients. However, the challenge is to obtain a comprehensive analysis from low-quality data and sparse measurements. In this paper, we present a method to estimate gait kinematics and kinetics directly from raw inertial sensor data performing a single dynamic optimization. We formulated an optimal control problem to track accelerometer and gyroscope data with a planar musculoskeletal model. In addition, we minimized muscular effort to ensure a unique solution and to prevent the model from tracking noisy measurements too closely. For evaluation, we recorded data of ten subjects walking …
Design And Analysis Of Novel Actuation Mechanism With Controllable Stiffness, Erivelton Gualter Dos Santos, Hanz Richter
Design And Analysis Of Novel Actuation Mechanism With Controllable Stiffness, Erivelton Gualter Dos Santos, Hanz Richter
Mechanical Engineering Faculty Publications
Actuators intended for human–machine interaction systems are usually designed to be mechanically compliant. Conventional actuators are not suitable for this purpose due to typically high stiffness. Advanced powered prosthetic and orthotic devices can vary their stiffness during a motion cycle and are power-efficient. This paper proposes a novel actuator design that modulates stiffness by means of a flexible beam. A motorized drive system varies the active length of the cantilever beam, thus achieving stiffness modulation. New large deflection formulation for cantilever beams with rolling contact constraints is used to determine the moment produced by the actuator. To validate the proposed …
Design, Control, And Optimization Of Robots With Advanced Energy Regenerative Drive Systems, Poya Khalaf
Design, Control, And Optimization Of Robots With Advanced Energy Regenerative Drive Systems, Poya Khalaf
ETD Archive
We investigate the control and optimization of robots with ultracapacitor based regenerative drive systems. A subset of the robot joints are conventional, in the sense that external power is used for actuation. Other joints are energetically self-contained passive systems that use ultracapacitors for energy storage. An electrical interconnection known as the star configuration is considered for the regenerative drives that allows for direct electric energy redistribution among joints, and enables higher energy utilization efficiencies. A semi-active virtual control strategy is used to achieve control objectives. We find closed-form expressions for the optimal robot and actuator parameters (link lengths, gear ratios, …
Advanced Processing Of Nickel-Titanium-Graphite Based Metal Matrix Composites, Amit K. Patil
Advanced Processing Of Nickel-Titanium-Graphite Based Metal Matrix Composites, Amit K. Patil
ETD Archive
A new class of in situ titanium carbide (TiC)/graphite (C) reinforced nickel matrix composites with variation in composition particularly varying C/Ti ratio have been processed using two different processing techniques. Firstly, via mechanical alloying (MA) followed by spark plasma sintering (SPS), i.e. solid-state processing. Secondly, using Laser engineered net shaping (LENSTM) technique, i.e. metal additive manufacturing technique. Mechanical alloying has gained special attention as a powerful non-equilibrium process for fabricating amorphous and nanocrystalline materials, whereas spark plasma sintering is a unique technique for processing dense and near net shape bulk alloys with homogeneous microstructure. Laser engineered net shaping (LENSTM) is …
A Reticulation Of Skin-Applied Strain Sensors For Motion Capture, Christopher A. Schroeck
A Reticulation Of Skin-Applied Strain Sensors For Motion Capture, Christopher A. Schroeck
ETD Archive
The purpose of this research is to develop a system of motion capture based on skin-applied strain sensors. These elastic sensors are of interest because they can be applied to the body without restricting motion and are well suited to operate in more practical environments, such as sports fields, gymnasiums, and outdoor areas. This combination is currently not available in the field of motion capture. The current issues with strain sensor motion capture technology is the accurate is not sufficient for motion analysis and axial rotation monitoring of joints is not available. This project will build and test a sensor …
Robust Impedance Control Of A Four Degree Of Freedom Exercise Robot, Santino Joseph Bianco
Robust Impedance Control Of A Four Degree Of Freedom Exercise Robot, Santino Joseph Bianco
ETD Archive
The CSU 4OptimX exercise robot provides a platform for future research into advanced exercise and rehabilitation. The robot and its control system will autonomously modify reference trajectories and impedances on the basis of an optimization criterion and physiological feedback. To achieve this goal, a robust impedance control system with trajectory tracking must be implemented as the foundational control scheme. Two control laws will be compared, sliding mode and H-infinity control. The above robust control laws are combined with underlying impedance control laws to overcome uncertain plant model parameters and disturbance anomalies affecting the input signal. The sliding mode control law …
Metabolic Cost Calculations Of Gait Using Musculoskeletal Energy Models, A Comparison Study, Anne D. Koelewijn, Dieter Heinrich, Antonie J. Van Den Bogert
Metabolic Cost Calculations Of Gait Using Musculoskeletal Energy Models, A Comparison Study, Anne D. Koelewijn, Dieter Heinrich, Antonie J. Van Den Bogert
Mechanical Engineering Faculty Publications
This paper compares predictions of metabolic energy expenditure in gait using seven metabolic energy expenditure models to assess their correlation with experimental data. Ground reaction forces, marker data, and pulmonary gas exchange data were recorded for six walking trials at combinations of two speeds, 0.8 m/s and 1.3 m/s, and three inclines, -8% (downhill), level, and 8% (uphill). The metabolic cost, calculated with the metabolic energy models was compared to the metabolic cost from the pulmonary gas exchange rates. A repeated measures correlation showed that all models correlated well with experimental data, with correlations of at least 0.9. The model …
State Estimation For An Agonistic‐Antagonistic Muscle System, Thang Tien Nguyen, Holly Warner, Hung La, Hanieh Mohammadi, Daniel J. Simon, Hanz Richter
State Estimation For An Agonistic‐Antagonistic Muscle System, Thang Tien Nguyen, Holly Warner, Hung La, Hanieh Mohammadi, Daniel J. Simon, Hanz Richter
Electrical and Computer Engineering Faculty Publications
Research on assistive technology, rehabilitation, and prosthetics requires the understanding of human machine interaction, in which human muscular properties play a pivotal role. This paper studies a nonlinear agonistic‐antagonistic muscle system based on the Hill muscle model. To investigate the characteristics of the muscle model, the problem of estimating the state variables and activation signals of the dual muscle system is considered. In this work, parameter uncertainty and unknown inputs are taken into account for the estimation problem. Three observers are presented: a high gain observer, a sliding mode observer, and an adaptive sliding mode observer. Theoretical analysis shows the …
Opensim Versus Human Body Model: A Comparison Study For The Lower Limbs During Gait, Antoine Falisse, Sam Van Rossom, Johannes Gijsbers, Frans Steenbrink, Ben J. Van Basten, Ilse Jonkers, Antonie J. Van Den Bogert, Friedl De Groote
Opensim Versus Human Body Model: A Comparison Study For The Lower Limbs During Gait, Antoine Falisse, Sam Van Rossom, Johannes Gijsbers, Frans Steenbrink, Ben J. Van Basten, Ilse Jonkers, Antonie J. Van Den Bogert, Friedl De Groote
Mechanical Engineering Faculty Publications
Musculoskeletal modeling and simulations have become popular tools for analyzing human movements. However, end users are often not aware of underlying modeling and computational assumptions. This study investigates how these assumptions affect biomechanical gait analysis outcomes performed with Human Body Model and the OpenSim gait2392 model. The authors compared joint kinematics, kinetics, and muscle forces resulting from processing data from 7 healthy adults with both models. Although outcome variables had similar patterns, there were statistically significant differences in joint kinematics (maximal difference: 9.8 degrees {[}1.5 degrees] in sagittal plane hip rotation), kinetics (maximal difference: 0.36 {[}0.10] N.m/kg in sagittal plane …
Capturing The Competing Influence Of Thermal And Mechanical Loads On The Strain Of Turbine Blade Coatings Via High Energy X-Rays, Albert Manero, Kevin Knipe, Janine Wischek, Carla Meid, John Okasinski, Jonathan Almer, Anette M. Karlsson, Marion Bartsch, Seetha Raghavan
Capturing The Competing Influence Of Thermal And Mechanical Loads On The Strain Of Turbine Blade Coatings Via High Energy X-Rays, Albert Manero, Kevin Knipe, Janine Wischek, Carla Meid, John Okasinski, Jonathan Almer, Anette M. Karlsson, Marion Bartsch, Seetha Raghavan
Mechanical Engineering Faculty Publications
This paper presents findings of synchrotron diffraction measurements on tubular specimens with a thermal barrier coating (TBC) system applied by electron beam physical vapor deposition (EB-PVD), having a thermally grown oxide (TGO) layer due to aging in hot air. The diffraction measurements were in situ while applying a thermal cycle with high temperature holds at 1000 °C and varying internal air cooling mass flow and mechanical load. It was observed that, during high temperature holds at 1000 °C, the TGO strain approached zero if no mechanical load or internal cooling was applied. When applying a mechanical load, the TGO in-plane …
Compensation For Inertial And Gravity Effects In A Moving Force Platform, Sandra K. Hnat, Ben J.H. Van Basten, Antonie J. Van Den Bogert
Compensation For Inertial And Gravity Effects In A Moving Force Platform, Sandra K. Hnat, Ben J.H. Van Basten, Antonie J. Van Den Bogert
Mechanical Engineering Faculty Publications
Force plates for human movement analysis provide accurate measurements when mounted rigidly on an inertial reference frame. Large measurement errors occur, however, when the force plate is accelerated, or tilted relative to gravity. This prohibits the use of force plates in human perturbation studies with controlled surface movements, or in conditions where the foundation is moving or not sufficiently rigid. Here we present a linear model to predict the inertial and gravitational artifacts using accelerometer signals. The model is first calibrated with data collected from random movements of the unloaded system and then used to compensate for the errors in …
Optimal Mixed Tracking/Impedance Control With Application To Transfemoral Prostheses With Energy Regeneration, Gholamreza Khademi, Hanieh Mohammadi, Hanz Richter, Daniel J. Simon
Optimal Mixed Tracking/Impedance Control With Application To Transfemoral Prostheses With Energy Regeneration, Gholamreza Khademi, Hanieh Mohammadi, Hanz Richter, Daniel J. Simon
Mechanical Engineering Faculty Publications
We design an optimal passivitybased tracking/impedance control system for a robotic manipulator with energy regenerative electronics, where the manipulator has both actively and semi-actively controlled joints. The semi-active joints are driven by a regenerative actuator that includes an energy-storing element. Method: External forces can have a large influence on energy regeneration characteristics. Impedance control is used to impose a desired relationship between external forces and deviation from reference trajectories. Multi-objective optimization (MOO) is used to obtain optimal impedance parameters and control gains to compromise between the two conflicting objectives of trajectory tracking and energy regeneration. We solve the MOO problem …