MEMS Functional Validation Using the Configuration Space Approach to Simulation and Analysis

We have developed an interactive computer-aided design program that supports mechanical design of devices fabricated in surface micro-machining processes. The program automates kinematic analysis via a novel configuration space computation code, performs real-time simulation, and supports functional parametric design. Designers can visualize system function under a range of operating conditions, can find and correct design flaws, and can optimize performance. We used the program to detect and correct a design flaw in a micro-mechanical indexing mechanism fabricated at Sandia with the SUMMiT process

Computing global configuration-space maps using multidimensional set-theoretic modelling

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Flexible Object Manipulation

Flexible objects are a challenge to manipulate. Their motions are hard to predict, and the high number of degrees of freedom makes sensing, control, and planning difficult. Additionally, they have more complex friction and contact issues than rigid bodies, and they may stretch and compress. In this thesis, I explore two major types of flexible materials: cloth and string. For rigid bodies, one of the most basic problems in manipulation is the development of immobilizing grasps. The same problem exists for flexible objects. I have shown that a simple polygonal piece of cloth can be fully immobilized by grasping all convex vertices and no more than one third of the concave vertices. I also explored simple manipulation methods that make use of gravity to reduce the number of fingers necessary for grasping. I have built a system for folding a T-shirt using a 4 DOF arm and a fixed-length iron bar which simulates two fingers. The main goal with string manipulation has been to tie knots without the use of any sensing. I have developed single-piece fixtures capable of tying knots in fishing line, solder, and wire, along with a more complex track-based system for autonomously tying a knot in steel wire. I have also developed a series of different fixtures that use compressed air to tie knots in string. Additionally, I have designed four-piece fixtures, which demonstrate a way to fully enclose a knot during the insertion process, while guaranteeing that extraction will always succeed

Manufacturability analysis for non-feature-based objects

This dissertation presents a general methodology for evaluating key manufacturability indicators using an approach that does not require feature recognition, or feature-based design input. The contributions involve methods for computing three manufacturability indicators that can be applied in a hierarchical manner. The analysis begins with the computation of visibility, which determines the potential manufacturability of a part using material removal processes such as CNC machining. This manufacturability indicator is purely based on accessibility, without considering the actual machine setup and tooling. Then, the analysis becomes more specific by analyzing the complexity in setup planning for the part; i.e. how the part geometry can be oriented to a cutting tool in an accessible manner. This indicator establishes if the part geometry is accessible about an axis of rotation, namely, whether it can be manufactured on a 4th-axis indexed machining system. The third indicator is geometric machinability, which is computed for each machining operation to indicate the actual manufacturability when employing a cutting tool with specific shape and size. The three manufacturability indicators presented in this dissertation are usable as steps in a process; however they can be executed alone or hierarchically in order to render manufacturability information. At the end of this dissertation, a Multi-Layered Visibility Map is proposed, which would serve as a re-design mechanism that can guide a part design toward increased manufacturability

Imaging of vertical seismic profiling data using the common-reflection-surface stack. Abbildungsverfahren für seismische Daten aus Bohrlochmessungen mit der Common-Reflection-Surface Stapelung

Diese Dissertation beschäftigt sich mit der Entwicklung eines automatisierten, datenorientierten Abbildungsverfahrens, das auf der sogenannten Common-Reflection-Surface (CRS) Stapelung basiert. Durch die Miteinbeziehung von benachbarten Experimenten bei der Rekonstruktion eines Einzelexperiments ergibt sich ein verbessertes Signal-zu-Rauschen Verhältnis und eine starke Bereinigung von Mehrdeutigkeiten. Hauptaugenmerk liegt auf der Adaption der Methode für Bohrloch- und Mehrkomponentendaten