Engineering Commons^™

Generalizable Methods For Modeling Lumbar Spine Kinematics, Craig Joseph Simons

Electronic Theses and Dissertations

A more complete understanding of lumbar spine kinematics could improve diagnoses and treatment of low back pathologies and may advance the development of biomechanical models. Kinematics describes motion of the five lumbar vertebrae without consideration for the forces that cause the motion. Despite considerable attention from researchers and clinicians, lumbar spine kinematics are not fully understood because the anatomy is not accessible for direct observation and the complex governing biomechanics produce small magnitude, coupled intervertebral movements.

The overall goal of this project was to develop a descriptive model of intervertebral lumbar spine kinematics that is applicable to a generalizable subject …

Investigation Of In-Vivo Hindfoot And Orthotic Interactions Using Bi-Planar X-Ray Fluoroscopy, Kristen M. Bushey

Electronic Thesis and Dissertation Repository

A markerless RSA method was used to determine the effect of orthotics on the normal, pes planus and pes cavus populations. Computed tomography (CT) was used to create bone models that were imported into the virtual environment. Joint coordinate systems were developed to measure kinematic changes in the hindfoot during weight-bearing gait and quiet standing. The objectives of this thesis were to (1) implement a fluoroscopy-based markerless RSA system on the foot, (2) determine the effect of various orthotics at midstance of fully weight-bearing dynamic gait, and (3) determine the effect of orthotics as measured using three different techniques. Every …

Multistable Shape-Shifting Surfaces (Mssss), Paul Joseph Montalbano

USF Tampa Graduate Theses and Dissertations

This paper presents designs for Multistable Shape-Shifting Surfaces (MSSS) by introducing bistability into the Shape-Shifting Surface (SSS). SSSs are defined as surfaces that retain their effectiveness as a physical barrier while undergoing changes in shape. The addition of bistability to the SSS gives the surface multiple distinct positions in which it remains when shifted to, i.e. by designing bistability into a single SSS link, the SSS unit cell can change into multiple shapes, and stabilize within the resulting shape, while maintaining integrity against various forms of external assaults normal to its surface. Planar stable configurations of the unit cell include, …

Dynamics, Electromyography And Vibroarthrography As Non-Invasive Diagnostic Tools: Investigation Of The Patellofemoral Joint, Filip Leszko

Doctoral Dissertations

The knee joint plays an essential role in the human musculoskeletal system. It has evolved to withstand extreme loading conditions, while providing almost frictionless joint movement. However, its performance may be disrupted by disease, anatomical deformities, soft tissue imbalance or injury. Knee disorders are often puzzling, and accurate diagnosis may be challenging. Current evaluation approach is usually limited to a detailed interview with the patient, careful physical examination and radiographic imaging. The X-ray screening may reveal bone degeneration, but does not carry sufficient information of the soft tissue conditions. More advanced imaging tools such as MRI or CT are available, …

Development Of A Rigid Body Forward Solution Physiological Model Of The Lower Leg To Predict Non Implanted And Implanted Knee Kinematics And Kinetics, John Kyle Patrick Mueller

Doctoral Dissertations

This dissertation describes the development and results of a physiological rigid body forward solution mathematical model that can be used to predict normal knee and total knee arthroplasty (TKA) kinematics and kinetics. The simulated activities include active extension and weight-bearing deep knee bend. The model includes both the patellofemoral and tibiofemoral joints. Geometry of the normal or implanted knee is represented by multivariate polynomials and modeled by constraining the velocity of lateral and medial tibiofemoral and patellofemoral contact points in a direction normal to the geometry surface.

Center of mass, ligament and muscle attachment points and normal knee geometry were …

Design And Analysis Of A Positively Engaged Continuously Variable Transmission, Brandon Levi Haupt

Theses and Dissertations

With energy demands at an all time high, mechanical power systems are under great scrutiny. Substantial efforts are being made throughout the world to reduce energy use in common mechanical systems such as the internal combustion engine and transmission system. Eliminating or reducing efficiency losses in the transmission is a potential source of improving the efficiency of the system. To do so, various alternative types of transmissions are being investigated. At Brigham Young University, development of a Positively Engaged Continuously Variable Transmission (PECVT) is progressing. In addition to the efficiency increases that would occur as a result of operating the …

Achieving Complex Motion With Fundamental Components For Lamina Emergent Mechanisms, Brian Geoffrey Winder

Theses and Dissertations

Designing mechanical products in a competitive environment can present unique challenges, and designers constantly search for innovative ways to increase efficiency. One way to save space and reduce cost is to use ortho-planar compliant mechanisms which can be made from sheets of material, or lamina emergent mechanisms (LEMs). This thesis presents principles which can be used for designing LEMs. Pop-up paper mechanisms use topologies similar to LEMs, so it is advantageous to study their kinematics. This thesis outlines the use of planar and spherical kinematics to model commonly used pop-up paper mechanisms. A survey of common joint types is given, …

Dynamic Response Of A Collidant Impacting A Low Pressure Airbag, Peter A. Dreher

Theses and Dissertations

There are many uses of low pressure airbags, both military and commercial. Many of these applications have been hampered by inadequate and inaccurate modeling tools. This dissertation contains the derivation of a four degree-of-freedom system of differential equations from physical laws of mass and energy conservation, force equilibrium, and the Ideal Gas Law. Kinematic equations were derived to model a cylindrical airbag as a single control volume impacted by a parallelepiped collidant. An efficient numerical procedure was devised to solve the simplified system of equations in a manner amenable to discovering design trends. The largest public airbag experiment, both in …

A Mechanized Horseback Riding Simulator As An Aid To Physical Therapy, Jennifer Lott

USF Tampa Graduate Theses and Dissertations

Equine-assisted therapy is a nontraditional form of physical therapy that involves riding horses as a form of rehabilitation. Limited access to these riding programs justifies a need to develop a horseback riding simulator capable of simulating the gaits, bend, and collection of the horse. Research involving the development of horseback riding simulators is limited, but the available research does show promising results in the ability to aid in physical therapy.

A two-dimensional model and simulation was developed using MATLAB. Using the results from the simulation, a horseback riding simulator was designed, fabricated and tested. The physical simulator was capable of …

The Design Of Adjustable Spherical Mechanisms Using Plane-To-Sphere And Sphere-To-Plane Projections, Wen-Tzong Lee

Dissertations

The spherical mechanism is a particular type of spatial mechanism. Due to the orientation of its joint axes and the curvature of its links, the workspaces of spherical mechanisms (whether line segments, closed loops or area regions) are spherical in curvature. This characteristic of spherical mechanisms makes them quite effective and practical in motion path and function generation applications requiring spherical rigid body kinematics.

Although there are design methods available for spherical mechanisms, most of these methods do not consider the design of a single adjustable spherical mechanism. With an adjustable spherical mechanism, the user could for example, relocate the …

Kinematic Analysis Of A Swash-Plate Mechanism Using Transformation Matrices, David Edgar Evans

Theses

The swash-plate mechanism is used to transfer rotational motion into translational motion and vice versa. Using transformation matrices to describe each joint, the displacements of the swash-plate mechanism were analyzed. The general transformation matrix model for the plane joint, not previously developed using transformation matrices, was presented. The solution was tested using a computer program. Examples of three different swash-plate angles; 10, 45, and 25' were considered. The solution was found to agree with previous solutions while offering a more complete description of the mechanism. Future work in this area could include a complete static, velocity, and/or dynamic analysis of …

Forward Kinematics Solution Of A Special Class Of General Stewart Platforms, Jian Li

Theses

A Stewart platform is a fully parallel, six-degree-of-freedom manipulator mechanism. A platform manipulator has a fixed platform acting as base, a mobile platform on which end-effector is mounted, and in-parallel kinematics chains (legs) between the two platforms. Although some direct position kinematics solutions for Stewart platforms of simplified geometry have been represented, to the best of our knowledge, no close-form direct kinematics solution for the general Stewart platform is available yet.

A common feature of six-degree-of-freedom Stewart platform of simplified geometry is the use of pairs of concentric ball joints. Due to inevitable manufacturing and assembly errors, practically there are …

Kinematic Synthesis Of Deployable-Foldable Truss Structures Using Graph Theory, Dirk B. Warnaar

Mechanical & Aerospace Engineering Theses & Dissertations

A graph theoretic approach is applied to the conceptual design of deployable truss structures. The characteristics that relate to the inter-connectivity of the elements of a deployable truss structure can be captured in a schematic representation, called a graph. A procedure is presented that enables the exhaustive generation of these graphs for structures of any given number of nodes and links and which are foldable onto a plane or onto a line.

A special type of truss structures, called truss modules, is presented. Graphs of this class of structures form a subset of the graphs of truss structures. Two procedures …