Biomedical Engineering and Bioengineering Commons^™

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. …

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 …

Neuromuscular Reflex Control For Prostheses And Exoskeletons, Sandra K. Hnat

ETD Archive

Recent powered lower-limb prosthetic and orthotic (P/O) devices aim to restore legged mobility for persons with an amputation or spinal cord injury. Though various control strategies have been proposed for these devices, specifically finite-state impedance controllers, natural gait mechanics are not usually achieved. The goal of this project was to invent a biologically-inspired controller for powered P/O devices. We hypothesize that a more muscle-like actuation system, including spinal reflexes and vestibular feedback, can achieve able-bodied walking and also respond to outside perturbations. The outputs of the Virtual Muscle Reflex (VMR) controller are joint torque commands, sent to the electric motors …

Predictive Simulations Of Gait And Their Application In Prosthesis Design, Anne D. Koelewijin

ETD Archive

Predictive simulations predict human gait by solving a trajectory optimization problem by minimizing energy expenditure. These simulations could predict the effect of a prosthesis on gait before its use. This dissertation has four aims, to show the application of predictive simulations in prosthesis design and to improve the quality of predictive simulations. Aim 1 was to explain joint moment asymmetry in the knee and hip in gait of persons with a transtibial amputation (TTA gait). Predictive simulations showed that an asymmetric gait required less effort. However, a small effort increase yielded a gait with increased joint moment symmetry and reduced …

Advanced Manufacturing Of Titanium Alloys For Biomedical Applications, Nicholas C. Mavros

ETD Archive

In metallurgy, Titanium has been a staple for biomedical purposes. Its low toxicity and alloying versatility make it an attractive choice for medical applications. However, studies have shown the difference in elastic modulus between Titanium alloys (116 GPa) and human bone (40-60 GPa) contribute to long term issues with loose hardware fixation. Additionally, long term studies have shown elements such as Vanadium and Aluminum, which are commonly used in Ti-6Al-4V biomedical alloys, have been linked to neurodegenerative diseases like Alzheimers and Parkinsons. Alternative metals known to be less toxic are being explored as replacements for alloying elements in Titanium alloys. …

Development And Verification Of A Mechanical Loading Device For Microfluidics, Stefan Habean, Erin Tesny

Undergraduate Research Posters 2017

Establishing the role that mechanics play in nerve cell (e.g. neurons) function requires experimental testing. Microfluidic based experiments are commonly used to study neuron growth and function, and studies have found mechanics to play an important role in neuron health. External loads can be applied to a microfluidic device using a motor, which presumably influences the mechanical environment of the cells. While a motor can easily apply known displacements, a “load cell” is necessary to measure corresponding forces. In an existing prototype microfluidic loading device, a load cell was integrated and verified. The manufacturer's calibration of the load cell was …

Design And Control Of A Powered Rowing Machine With Programmable Impedance, Jose Humberto De La Casas Zolezzi

ETD Archive

Due to the rise of obesity, diabetes and cardiovascular disease, research in human performance and physical activity has received increased attention. Rowing machines are used for performance improvements through concentric exercises, however a combination of concentric and eccentric actions is known to improve the effectiveness of training. In this work, a conventional rowing machine was modified to include an electric motor and a robust impedance control system, enabling programmable impedance with concentric and eccentric capabilities. Eccentric exercises are known to contribute significantly to the efficacy of training and to diminish the detrimental effects of humans operating in microgravity for long …

Real-Time Simulation Of Three-Dimensional Shoulder Girdle And Arm Dynamics, Edward K. Chadwick, Dimitra Blana, Robert F. Kirsch, Antonie J. Van Den Bogert

Antonie J. van den Bogert

Electrical stimulation is a promising technology for the restoration of arm function in paralyzed individuals. Control of the paralyzed arm under electrical stimulation, however, is a challenging problem that requires advanced controllers and command interfaces for the user. A real-time model describing the complex dynamics of the arm would allow user-in-the-loop type experiments where the command interface and controller could be assessed. Real-time models of the arm previously described have not included the ability to model the independently controlled scapula and clavicle, limiting their utility for clinical applications of this nature. The goal of this study therefore was to evaluate …

Personal Navigation Via High-Resolution Gait-Corrected Inertial Measurement Units, Özkan Bebek, Michael A. Suster, Srihari Rajgopal, Michael J. Fu, Xuemei Huang, M. Cenk Çavu¸So˘Glu,, Darrin J. Young, Mehran Mehregany, Antonie J. Van Den Bogert, Carlos H. Mastrangelo

Mechanical Engineering Faculty Publications

In this paper, a personal micronavigation system that uses high-resolution gait-corrected inertial measurement units is presented. The goal of this paper is to develop a navigation system that uses secondary inertial variables, such as velocity, to enable long-term precise navigation in the absence of Global Positioning System (GPS) and beacon signals. In this scheme, measured zerovelocity duration from the ground reaction sensors is used to reset the accumulated integration errors from accelerometers and gyroscopes in position calculation. With the described system, an average position error of 4 m is achieved at the end of half-hour walks.

An Analytical Model For Rotator Cuff Repairs, A. Aurora, Jorge E. Gatica, Antonie J. Van Den Bogert, J. A. Mccarron, Kathleen A. Derwin

Mechanical Engineering Faculty Publications

Background

Currently, natural and synthetic scaffolds are being explored as augmentation devices for rotator cuff repair. When used in this manner, these devices are believed to offer some degree of load sharing; however, no studies have quantified this effect. Furthermore, the manner in which loads on an augmented rotator cuff repair are distributed among the various components of the repair is not known, nor is the relative biomechanical importance of each component. The objectives of this study are to (1) develop quasi-static analytical models of simplified rotator cuff repairs, (2) validate the models, and (3) predict the degree of load …

A Real-Time, 3-D Musculoskeletal Model For Dynamic Simulation Of Arm Movements, Edward K. Chadwick, Dimitra Blana, Antonie J. Van Den Bogert, Robert F. Kirsch

Mechanical Engineering Faculty Publications

Neuroprostheses can be used to restore movement of the upper limb in individuals with high-level spinal cord injury. Development and evaluation of command and control schemes for such devices typically require real-time, ldquopatient-in-the-looprdquo experimentation. A real-time, 3-D, musculoskeletal model of the upper limb has been developed for use in a simulation environment to allow such testing to be carried out noninvasively. The model provides real-time feedback of human arm dynamics that can be displayed to the user in a virtual reality environment. The model has a 3-DOF glenohumeral joint as well as elbow flexion/extension and pronation/supination and contains 22 muscles …

Comment On "Quadriceps Protects The Anterior Cruciate Ligament", Antonie J. Van Den Bogert

Mechanical Engineering Faculty Publications

No abstract provided.