This thesis concerns parallel, platform mechanisms, consisting of two distal links that are connected to each other by a set of open kinematic chains, called legs. Particularly, mechanisms with redundant loops, kinematically quite challenging, are investigated. Existing methods of analysis and their shortcomings are outlined and alternatives which help to overcome them are developed. / Definitions and analyses of platform mechanisms, mobility and degree-of-freedom are reviewed. Kinematic analysis and workspace determination of platform mechanisms are thoroughly investigated. / An algebraic method, based on the functional matrix of mechanisms, as defined by Freudenstein, is applied to determine their degree of freedom (DOF). It is shown with examples that this method unambiguously yields the DOF for mechanisms where other methods fail. / The effects of extra legs, and hence, redundant loops, are discussed. The statics, differential and positional kinematics of these mechanisms are investigated. Kinematic-mapping techniques are used to analyze the constraints applied by individual legs to the platform. Current methods of workspace analysis of platform mechanisms are reviewed. A novel technique, which contains both position and orientation information, is introduced. It is shown that this method successfully treats platform mechanisms, with or without redundant loops. However, it may be computationally expensive for some mechanisms, such as spherical wrist mechanisms. An alternative technique, based on the Euler-Rodrigues parameters of a rotation, is also introduced for spherical mechanisms, of both serial and platform types. / The features of some of the methods introduced here are applied to a novel mechanism introduced elsewhere, namely, the double-tetrahedral mechanism (DTM), which it is a paradigm of closed-loop mechanisms with redundant loops.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:QMM.34706 |
| Date | January 1998 |
| Creators | Bulca, Ferhan. |
| Contributors | Angeles, Jorge (advisor), Zsombor-Murray, Paul J. (advisor) |
| Publisher | McGill University |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Format | application/pdf |
| Coverage | Doctor of Philosophy (Department of Mechanical Engineering.) |
| Rights | All items in eScholarship@McGill are protected by copyright with all rights reserved unless otherwise indicated. |
| Relation | alephsysno: 001618620, proquestno: NQ44374, Theses scanned by UMI/ProQuest. |
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