70 research outputs found
Self-motions of pentapods with linear platform
We give a full classification of all pentapods with linear platform
possessing a self-motion beside the trivial rotation about the platform. Recent
research necessitates a contemporary and accurate re-examination of old results
on this topic given by Darboux, Mannheim, Duporcq and Bricard, which also takes
the coincidence of platform anchor points into account. For our study we use
bond theory with respect to a novel kinematic mapping for pentapods with linear
platform, beside the method of singular-invariant leg-rearrangements. Based on
our results we design pentapods with linear platform, which have a simplified
direct kinematics concerning their number of (real) solutions.Comment: 28 pages, 5 figure
Liaison Linkages
The complete classification of hexapods - also known as Stewart Gough
platforms - of mobility one is still open. To tackle this problem, we can
associate to each hexapod of mobility one an algebraic curve, called the
configuration curve. In this paper we establish an upper bound for the degree
of this curve, assuming the hexapod is general enough. Moreover, we provide a
construction of hexapods with curves of maximal degree, which is based on
liaison, a technique used in the theory of algebraic curves.Comment: 40 pages, 6 figure
Mobile Icosapods
Pods are mechanical devices constituted of two rigid bodies, the base and the platform, connected by a number of other rigid bodies, called legs, that are anchored via spherical joints. It is possible to prove that the maximal number of legs of a mobile pod, when finite, is 20. In 1904, Borel designed a technique to construct examples of such 20-pods, but could not constrain the legs to have base and platform points with real coordinates. We show that Borel’s construction yields all mobile 20-pods, and that it is possible to construct examples where all coordinates are real
A new line-symmetric mobile infinity-pod
We construct parallel manipulators with one degree of freedom and admitting
infinitely many legs lying on a curve of degree ten and genus six. Our
technique relies upon a duality between the spaces parametrizing all the
possible legs and all the possible configurations of a manipulator. Before
describing our construction, we show how this duality helps explaining several
known phenomena regarding mobility of parallel manipulators.Comment: 14 page
Kinematics and Robot Design I, KaRD2018
This volume collects the papers published on the Special Issue “Kinematics and Robot Design I, KaRD2018” (https://www.mdpi.com/journal/robotics/special_issues/KARD), which is the first issue of the KaRD Special Issue series, hosted by the open access journal “MDPI Robotics”. The KaRD series aims at creating an open environment where researchers can present their works and discuss all the topics focused on the many aspects that involve kinematics in the design of robotic/automatic systems. Kinematics is so intimately related to the design of robotic/automatic systems that the admitted topics of the KaRD series practically cover all the subjects normally present in well-established international conferences on “mechanisms and robotics”. KaRD2018 received 22 papers and, after the peer-review process, accepted only 14 papers. The accepted papers cover some theoretical and many design/applicative aspects
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