Path planning of parallel manipulators in configuration space
thesisposted on 01.03.2017 by Au, Wesley John Kin-Wai
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Path planning for parallel manipulators, especially for manipulators greater than three degrees of freedom (DOF) is a challenging task for many reasons. Due to the complicated nature of their kinematics and the dangerous effects of parallel singularities, path planning of these manipulators can be computationally expensive and often the side-effect is that the overall reachable workspace is constrained to a very small operational area. To compound the issue, the workspace of parallel manipulators greater than three DOF can no longer be represented in 3D space, which hinders the ability to understand the workspace we are planning a trajectory in. The aim of our research is to develop a systematic way to perform trajectory planning on a wide range of non-redundant parallel manipulators of higher DOFs. By introducing novel concepts such as the global workspace roadmap to enhance the overall reachable workspace and the rotary disk search and efficient flood-fill algorithms to handle higher-dimensional spaces, we have been able to perform path planning on a variety of parallel manipulators efficiently of up to 6-DOF. We have successfully applied our novel path planning scheme on the 2-DOF 5R, 3-DOF 3-RPR and 3-RRR parallel manipulators, and the 6-DOF Stewart-Gough platform.