Mechanical Engineering Commons^™

Force And Motion Based Methods For Planar Human-Robot Co-Manipulation Of Extended Objects, Erich Allen Mielke

Theses and Dissertations

As robots become more common operating in close proximity to people, new opportunities arise for physical human-robot interaction, such as co-manipulation of extended objects. Co-manipulation involves physical interaction between two partners where an object held by both is manipulated in tandem. There is a dearth of viable high degree-of-freedom co-manipulation controllers, especially for extended objects, as well as a lack of information about how human-human teams perform in high degree-of-freedom tasks. One method for creating co-manipulation controllers is to pattern them off of human data. This thesis uses this technique by exploring a previously completed experimental study. The study involved …

Adaptive Control For Inflatable Soft Robotic Manipulators With Unknown Payloads, Jonathan Spencer Terry

Theses and Dissertations

Soft robotic platforms are becoming increasingly popular as they are generally safer, lighter, and easier to manufacture than their more rigid, heavy, traditional counterparts. These soft platforms, while inherently safer, come with significant drawbacks. Their compliant components are more difficult to model, and their underdamped nature makes them difficult to control. Additionally, they are so lightweight that a payload of just a few pounds has a significant impact on the manipulator dynamics. This thesis presents novel methods for addressing these issues. In previous research, Model Predictive Control has been demonstrably useful for joint angle control for these soft robots, using …

A Comparative Analysis Of Computer-Aided Collaborative Design Tools And Methods, Keenan Louis Eves

Theses and Dissertations

Collaboration has always been critical to the success of new product development teams, and the advent of geographically dispersed teams has significantly altered the way that team members interact. Multi-user computer-aided design (MUCAD) and crowdsourcing are two results of efforts to enable collaboration between geographically dispersed individuals. In this research, a study was done to investigate the differences in performance between MUCAD and single-user CAD teams, in which teams competed to create the best model of a hand drill. This was done across a three-day period to recreate the scenario found in industry. It was found that MUCAD increases awareness …

Total Hemispherical Apparent Radiative Properties Of The Infinite V-Groove With Specular Reflection, Rydge B. Mulford, Nathan S. Collins, Michael S. Farnsworth, Matthew R. Jones, Brian D. Iverson

Faculty Publications

Multiple reflections in a cavity geometry augment the emission and absorption of the cavity opening relative to a flat surface in a phenomenon known as the cavity effect. The extent of the cavity effect is quantified using apparent absorptivity and apparent emissivity. Analysis of complicated thermal systems is simplified through application of apparent radiative properities to cavity geometries. The apparent radiative properties of a specularly-reflecting, gray, isothermal V-groove have been derived analytically, but these results have not been validated experimentally or numerically. Additionally, the model for apparent absorptivity of an infinite V-groove subjected to partial illumination in the presence of …

Toward A Production Ready Fbj Process For Joining Dissimilar Combinations Of Gadp 1180 Steel And Aa 7085-T76, Kevin Alexander Shirley

Theses and Dissertations

Friction Bit Joining (FBJ) is a new technology that can be used to join dissimilar materials together. This ability makes it a good candidate for creating light weight structures for the automotive industry by combining lightweight materials such as aluminum to stronger materials like advanced high-strength steels. The automotive industry and many other industries have great interest in reducing structure weight to increase fuel efficiency. The purpose of this research is to make FBJ of GADP 1180 to AA 7085-T76 a production ready process by (1) better understanding the effects of process parameters, bit design and tool design on joint …

Symmetric Equations For Evaluating Maximum Torsion Stress Of Rectangular Beams In Compliant Mechanisms, Guimin Chen, Larry L. Howell

Faculty Publications

There are several design equations available for calculating the torsional compliance and the maximum torsion stress of a rectangular cross-section beam, but most depend on the relative magnitude of the two dimensions of the cross-section (i.e., the thickness and the width). After reviewing the available equations, two thickness-to-width ratio independent equations that are symmetric with respect to the two dimensions are obtained for evaluating the maximum torsion stress of rectangular cross-section beams. Based on the resulting equations, outside lamina emergent torsional joints are analyzed and some useful design insights are obtained. These equations, together with the previous work on symmetric …

A Method For Characterizing Essential Tremor From The Shoulder To The Wrist, Daniel W. Geiger, Dennis Eggett, Steven K. Charles

Faculty Publications

Background

Despite the pervasive and devastating effect of Essential Tremor (ET), the distribution of ET throughout the upper limb is unknown. We developed a method for characterizing the distribution of ET and performed a preliminary characterization in a small number of subjects with ET.

Methods

Using orientation sensors and inverse kinematics, we measured tremor in each of the seven major degrees of freedom (DOF) from the shoulder to the wrist while ten patients with mild ET assumed 16 different postures. We described the tremor in each DOF in terms of power spectral density measures and investigated how tremor varied between …

Improving And Predicting The Effectiveness Of Dispersed, Multi-Disciplinary Design Teams, Matthew Oliver Wald

Theses and Dissertations

The use of dispersed (virtual) teams is growing rapidly in the engineering profession. To help prepare students for work in this type of industry, university engineering courses are requiring students to work in teams. Industry leaders and university faculty are interested in improving and measuring the performance of these distributed teams. Surveys, interviews, and observations from the AerosPACE Partners for the Advancement of Collaborative Engineering (AerosPACE) capstone design course are examined to demonstrate how different collaboration tools can be used to best enhance a distributed design team's effectiveness. Collaboration tools to which distributed design teams should give extra consideration at …

Distributed Electric Propulsion Effects On Traditional Aircraft Through Multidisciplinary Optimization, Kevin Moore, Andrew Ning

Faculty Publications

Electric aircraft face a steep tradeoff between the demand for runway performance and range. While fuel based propulsion technologies typically increase in specific power with increasing size, electric propulsion is typically much more scalable. This system scalability enables alternative designs including distributed propulsion, optionally powered propulsion units, and vectored thrust, which can all contribute to better runway performance and range. In this paper, we explore how continuously powered distributed propulsion can reduce takeoff distance while still satisfying range constraints. We use a combination of a blade element momentum method, a vortex lattice method, experimental data, and nonlinear optimization techniques to …

Multidisciplinary Design Optimization Of Flexible Solar-Regenerative High-Altitude Long-Endurance Aircraft, Taylor Mcdonnell, Judd Mehr, Andrew Ning

Faculty Publications

Solar-Regenerative High-Altitude Long-Endurance (SR-HALE) aircraft are designed to sustain year-round flight at high altitudes indefinitely. No SR-HALE aircraft has yet accomplished this task due to the complex network of environmental, solar, structural, and aerodynamic trade-offs, among which aircraft flexibility plays a key role. A comprehensive SR-HALE aircraft multidisciplinary design optimization framework is developed in which the flexible aircraft analysis tool ASWING is incorporated in order to constrain nonlinear aeroelasticity. Energy, battery, ply thickness, material failure, local buckling, aerodynamic stall, longitudinal stability, and general stability (including flutter) constraints are applied in order to reasonably constrain the optimized SR-HALE aircraft design. An …

Benefits Of Two Turbine Rotor Diameters And Hub Heights In The Same Wind Farm, Andrew Pj Stanley, Andrew Ning, Katherine Dykes

Faculty Publications

Significant turbine-wake interactions greatly reduce power output in a wind farm. If different turbine hub heights and rotor diameters are included in the same wind farm, the wake interference in the farm will be reduced, resulting in a lower cost of energy (COE) than a farm with identical turbines. In this paper, we present a method to model wind farm COE in farms with hub heights and rotor diameters that vary across the wind farm. We also demonstrate how to optimize these wind farms to minimize COE. The results show that COE can be greatly reduced in wind farms with …

Large-Scale Multidisciplinary Optimization Of An Electric Aircraft For On-Demand Mobility, John Hwang, Andrew Ning

Faculty Publications

Distributed electric propulsion is a key enabling technology for on-demand electric aircraft concepts. NASA’s X-57 Maxwell X-plane is a demonstrator for this technology, and it features a row of high-lift propellers distributed along the leading edge of its wing to enable better aerodynamic efficiency at cruise and improved ride quality in addition to less noise and emissions. This study applies adjoint- based multidisciplinary design optimization to this highly coupled design problem. The propulsion, aerodynamics, and structures are modeled using blade element momentum theory, the vortex lat- tice method, and finite element analysis, respectively, and the full mission profile is discretized …

Controlling Normal Stiffness In Droplet-Based Linear Bearings, Qi Ni, Nathan B. Crane

Faculty Publications

While Capillary forces are negligible relative to gravity at the macroscale, they provide adequate force to effectively manipulate millimeter to micro meter objects. The fluidic actuation can be accomplished using droplets that also act as bearings. While rotary droplet bearings have been previously demonstrated, this paper considers the performance potential of discrete droplets acting as linear bearings. Specifically, it addresses the positioning accuracy of a droplet-based bearing consisting of a droplet between a moving plate and a stationary substrate with constrained wetting region under a normal load using both closed form analytical solutions and numerical simulations. The vertical force and …

Impact Of Vapor Polishing On Surface Quality And Mechanical Properties Of Extruded Abs, Clayton Neff, Matthew Trapuzzano, Nathan B. Crane

Faculty Publications

Purpose — Additive manufacturing (AM) is readily capable of producing models and prototypes of complex geometry and is advancing in creating functional parts. However, AM processes typically underperform traditional manufacturing methods in mechanical properties, surface roughness, and hermeticity. Solvent vapor treatments (vapor polishing) are commonly used to improve surface quality in thermoplastic parts, but the results are poorly characterized.

Design/methodology/approach — This work quantifies the surface roughness change and also evaluates the effect on hermeticity and mechanical property impacts for “as-printed” and acetone vapor-polished ABS tensile specimens of 1, 2, and 4 mm thicknesses produced by material extrusion (FDM).

Findings …

Investigation Into Integrated Free-Form And Precomputational Approaches For Aerostructural Optimization Of Wind Turbine Blades, Ryan Timothy Barrett

Theses and Dissertations

A typical approach to optimize wind turbine blades separates the airfoil shape design from the blade planform design. This approach is sequential, where the airfoils along the blade span are pre-selected or optimized and then held constant during the blade planform optimization. In contrast, integrated blade design optimizes the airfoils and the blade planform concurrently and thereby has the potential to reduce cost of energy (COE) more than sequential design. Nevertheless, sequential design is commonly performed because of the ease of precomputation, or the ability to compute the airfoil analyses prior to the blade optimization. This research investigates two integrated …