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The objective of the work described in this thesis is the development of a configuration estimation scheme for quasi soft-bodied robots, with the end goal being accurate soft-robot proprioception to enable robotic manipulation of unknown external loads. The first chapter introduces the problem and state-of-the-art modeling methods. The second chapter presents work we did building on previous research on a novel sensing scheme for soft-bodied robotic configuration estimation. The third chapter discusses the development of a geometric shape-sensing model based on overlapping tendon-length measurements. This model is geometrically exact for a body composed of two constant curvature segments in bending. The next chapter discusses our implemention of this model on a real world system and tested in two and three dimensions. We estimated the shape of a 215 mm long robotic segment with less then 3 mm of median error for a set of 50 configurations causing motion in two dimensions and approximately 27 mm of median translational error in three dimensions. The final chapter draws conclusions and proposes future work to allow for full robotic proprioception.

Let X be a planar or one-dimensional Peano continuum. Let E be a Hawaiian Earring with fundamental group H. We show that every homomorphism from H to the fundamental group of X is conjugate to a homomorphism which is induced by a continuous function.

Continuum robots, with the capability of bending and extending at any point along their length mimic the abilities of an octopus arm or an elephant trunk. These manipulators present a number of exciting possibilities. While calculating a static solution for the system has been proven with certain models to produce satisfactory results [1], this approach ignores the significant effects a dynamics solution captures. However, adding time and studying the physical effects produced on a continuum robot involves calculation of the robot’s shape at a number of discrete points. Typically, the separation between points will be very small and thus a solution requires large amounts of computational power. We present a method to improve calculation speed for dynamic problems with the use of CUDA, a framework for parallel GPU computing. GPUs are ideally suited for massively parallel computations because of their multi-processor architecture. Our dynamics solution will take advantage of this parallel environment.

Continuum robots are the biologically inspired robots that mimic the behaviors of mammalian tongues, elephant trunks, and octopus arms. These robots feature a backboneless structure similar to their biological counterparts, such as termed muscular hydrostats. The drawbacks of two existing designs are examined and a new mechanical design that uses a single latex rubber tube as the central member is proposed, providing a design that is both simple and robust. Next, a novel verification procedure is applied to examine the validity of the proposed model in two different domains of applicability. A two-level electrical control scheme enables rapid prototyping and can be used to control the continuum robot remotely with a joystick via a Local Area Network (LAN). Next, a new geometrical approach to solve inverse kinematics for continuum type robot manipulators is introduced. Given the tip of a three-section robot, end-points of section 1 and section 2 are computed, and a complete inverse kinematics solution for a multisection continuum robot is then achieved by applying inverse kinematics to each section continuum trunk. Moreover, the algorithm provides a solution space rather than a single valid solution. Finally, the techniques involved in visualization of AirOctor/OctArm in 3D space in real-time are discussed.The algorithm has been tested with several system topologies.

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An important part of an aerodynamic design process is optimizing designs to maximize quantities such as lift and the lift-to-drag ratio, in a process known as shape optimization. It is the goal of this thesis to develop and apply understanding of mixed finite element method and sensitivity analysis in a way that sets the foundation for shape optimization. The open-source Incompressible Flow Iterative Solution Software (IFISS) mixed finite element method toolbox for MATLAB developed by Silvester, Elman, and Ramage is used. Meshes are produced for a backward-facing step problem, using built-in tools from IFISS as well as the mesh generation software Gmsh, and grid convergence studies are performed for both sets of meshes along a sampled data line to ensure that the simulations converge asymptotically with increasing mesh resolution. As a preliminary study of sensitivity analysis, analytic sensitivities of velocity components along the backward-facing step data line to inflow velocity parameters are determined and verified using finite difference and complex step sensitivity values. The method is then applied to pressure drag calculated by integrating the pressure over the surface of a circular cylinder in a freestream flow, and verified and validated using published simulation data and experimental data. The sensitivity analysis study is extended to shape optimization, wherein the shape of a circular cylinder is altered and the sensitivities of the pressure drag coefficient to the changes in the cylinder shape are determined and verified. / Master of Science

Cellular core structures are the state-of-the-art technology for light weight structures in the aerospace industry. In an aerospace product, sandwich panels with cellular core represent the primary structural component as a given aerospace product may contain a large number of sandwich panels. This reveals the necessity of understanding the mechanical behavior of the cellular core and the impact of that behavior on the overall structural behavior of the sandwich panel, and hence the final aerospace product. As the final aerospace product must go through multiple qualification tests to achieve a final structure that is capable of withstanding all environments possible, analyzing the structure prior to testing is very important to avoid any possible failures and to ensure that the final design is indeed capable of withstanding the loads. To date, due to the lack of full understanding of the mechanical behavior of cellular cores and hence the sandwich panels, there still remains a significant lack of analytical capability to predict the proper behavior of the final product and failures may still occur even with significant effort spent on pre-test analyses. Analyzing cellular core to calculate the equivalent material properties of this type of structure is the only way to properly design the core for sandwich enhanced stiffness to weight ratio of the sandwich panels. A detailed literature review is first conducted to access the current state of development of this research area based on experiment and analysis. Then, one of the recently developed homogenization schemes is chosen to investigate the mechanical behavior of heavy, non-corrugated square cellular core with a potential application in marine structures. The mechanical behavior of the square cellular core is then calculated by applying the displacement approach to a representative unit cell finite element model. The mechanical behavior is then incorporated into sandwich panel finite element model and in an in-house code to test the predicted mechanical properties by comparing the center-of-panel displacement from all analyses to that of a highly detailed model. The research is then expanded to cover three cellular core shapes, hexagonal cores made of corrugated sheets, square cores made of corrugated sheets, and triangular cores. The expansion covers five different cell sizes and twenty one different core densities for each of the core shapes considering light cellular cores for space applications, for a total of 315 detailed studies. The accuracy of the calculated properties for all three core shapes is checked against highly detailed finite element models of sandwich panels. Formulas are then developed to calculate the mechanical properties of the three shapes of cellular cores studied for any core density and any of the five cell sizes. An error analysis is then performed to understand the quality of the predicted equivalent properties considering the panel size to cell size ratio as well as the facesheet thickness to core thickness ratio. The research finally expanded to understand the effect of buckling of the unit cell on the equivalent mechanical property of the cellular core. This part of the research is meant to address the impact of the local buckling that may occur due to impact of any type during the manufacturing, handling or assembly of the sandwich panels. The variation of the equivalent mechanical properties with the increase in transverse compression load, until the first folding of the unit cell is complete, is calculated for each of the three core shapes under investigation. / Ph. D.

This thesis is about a potential trade-off between integrity and long-term usability in the choice of file formats for preservation of text documents. Five common formats are discussed: plain text, PDF/A, Office Open XML Document, Open Document Text, and Markdown. The formats are compared with respect to four criteria related to integrity and usability and to the records continuum model: support by widely used software, stability, rendering of contents and reusability. It is concluded that no single format is optimal with respect to all four criteria, when it comes to preserving typical documents in a modern environment, with more or less complex formatting and document structure. Therefore, the feasiblity of using two or more formats for preservation of a single document (e.g. PDF/A combined with Markdown and/or Office Open XML) is discussed. It is necessary to weigh the importance of integrity and long-term usability against the costs of preserving documents in multiple formats. This is a two years master's thesis in Archival Science, Library and Museum studies.

Par définition, les intérimaires ne sont liés que par des contrats temporaires et pourtant on constate que 165 000 personnes ont travaillé pendant plus de six mois en intérim chaque année entre 1998 et 2002. L’existence de ces intérimaires longue-durée est ici interrogée en partant de l’hypothèse que leur maintien dans cette forme d’emploi est lié à l’état de la norme salariale qui perd peu à peu sa place de principe organisateur de la société française. Plusieurs éléments permettent de comprendre ce maintien. Le premier est un rapport de confiance activement entretenu entre l’intérimaire et l’agence d’intérim. Deuxièmement, il est nécessaire pour les intérimaires longue-durée, de posséder des attaches familiales ou immobilières. Enfin, au sein des entreprises utilisatrices, les rapports entre intérimaires et embauchés sont facilités par l’affaiblissement du sentiment de sécurité lié au contrat à durée indéterminée.Les bonnes raisons du maintien en intérim sont donc liées à la crainte du chômage mais aussi à l’abandon du compromis entre sphères politiques et économiques de l’Etat assurantiel. La sécurité qu’apporte l’emploi stable est remise en cause alors qu’il est nécessaire pour obtenir les prêts qui mènent à la propriété immobilière. Or, cette dernière semble reprendre sa place de garant et permet à ceux qui y ont accès de sortir du continuum salarial sans subir de sanctions et de participer à son affaiblissement. / By definition, temporary workers are only bound by temporary contracts, yet we find that, between 1998 and 2002, 165 000 people have been employed as temporary workers each year for more than six months.In this research, we raise the question of the existence of these long term temporary workers through the presumption that their existence is linked to the state of the wage continuum that is gradually losing its place as the organizing principle of French society. Through a qualitative survey, we highlight the importance of several elements. First, trust is actively maintained between the temporary worker and the agency. Secondly, the long-term temporary workers rely on family or estate to secure their position. In addition to these prerequisites, we find that, when sent on a mission, temporary workers benefit from the weakening of the security feeling that permanent contracts used to provide.Good reasons behind long term-temporary work are related to the fear of unemployment and to the resignation of the trade-off between political and economic spheres that gave birth to the insurance-State. The security of steady employment is now being questioned while it is needed to obtain loans necessary to purchase home ownership. At the same time, the latter seems to take its place as guarantor and allows home owners to deviate from the continuum wage without repercussion while participating in its weakening.