Browsing by Subject "Three-dimensional"

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    Development of a Three-Dimensional Least Squares Adjustment Program
    (1994-12) Johnson, Gerald W.
    In the past horizontal position (X and Y coordinates) and vertical position (elevation) have been measured and computed in separate surveying operations. In order to take full advantage of the three-dimensional measurement capability of their "total station" surveying instruments, Mn/DOT wanted a user friendly least squares adjustment program that would simultaneously incorporate all three measurements - distance, horizontal angle and vertical angle in a common adjustment procedure. The only practical way to do this is to use a least squares adjustment program that can determine both horizontal and vertical components in the same adjustment procedure. There are commercial and government adjustment programs available that will do a three dimensional least squares adjustment, and the new program is not unique in that sense. It is unique, however, in that it satisfies special Mn/DOT requirements, particularly with respect to input and output format which is the SDMS (Survey Data Management System) format. In addition the program incorporates a simplified weighting procedure which allows the user to alter the weighting parameters if that should be necessary. Although not a part of the original agreement, it became apparent during program testing that a field test facility would benefit the project and also provide a site for on-going equipment testing and performance checking. Thus the idea for a permanent three-dimension test site came into being.
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    Pantomeshes: kinematics, synthesis, and applications of closed pantograph-style linkage systems.
    (2010-12) Larson, Blake Timothy
    This research describes the kinematics, analysis, and synthesis of a pantomesh. A pantomesh is a patchwork assembly of pantograph elements (known elsewhere as scissor pairs or duplets) that obey certain mobility requirements. A pantomesh, as described in this thesis, has scissor-like elements connected to one another by spherical joints to allow a wide variety of motions. Previous pantograph-style linkages, such as the Hoberman Sphere, use special geometry restrictions and have elements joined with gussets, thereby limiting the variety of shapes possible. The thesis begins with examining the kinematics of pantomeshes and their constituent parts. First, the kinematics of the individual pantograph elements are detailed for further use. The mobility of a closed pantomesh is ensured by the mobility of its constituent pantopatches, two-wide by two-high sub-assemblies of pantograph elements that must be mobile themselves for the entire pantomesh to be mobile. A new method for mobility of spatial linkages is presented relating the use of polygonal elements. Next, two methods for pantomesh synthesis are presented. A graphical method is presented to use a computer-aided design system to create a mobile pantomesh that meets specified requirements. A computational method for synthesis is also presented, using a numerical optimization method to create pantomeshes to certain specifications. Practical considerations of manufacturing are considered in the discussion of multi-link spherical joints, including past work and new approaches. The new approaches include a compliant multi-link spherical joint and a crossed-tendon system that acts a a spherical joint. Finally, an application is presented: a new linkage which provides radial pressure for the purpose of stabilizing a human breast during cancer-related diagnosis and treatment procedures.