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Three and Six Degree of Freedom Double Triangular Manipulators

The advantages of greater speed, rigidity and payload-to-mass ratio, peculiar to parallel manipulators with respect to their serial counterparts, are well known and have been often stated. However it is usually difficult to analyze the forward kinematics and dynamics of six degree of freedom parallel architectures. Recently we have resumed the investigation of a class platform manipulators, called double triangular and based on the results of H.R.M. Daniali (Ph.D. '95). Of particular interest is the simplest, planar version(PDTM) which is being constructed as a machine tool platform. This architecture should lead to superior machine tool designs. Consider that the usual x-y-z milling table, with three orthogonal, serial slide-ways, lacks rotational capacity and the drives are serially mounted. The PDTM has full planar mobility, and the three lead-screws are base-driven and constitute the structural support as well. Coupled with a PR machining head, a full five DOF milling machine may be thus realized. This is believed to be a better design than the new, radically unconventional inverted Stewart-Gough platform milling machines which have enjoyed limited success but have also been prone to singularities which lead to destructive failures. It is also felt that the PDTM architecture will provide greater dexterity than existing millers and will, like x-y-z positioners, be singularity-free within their substantial workspace.

J.C.F. Shum, N. Tilson, P.J. Zsombor-Murray
 


Annual Report

Mon Jun 26 21:22:20 GMT 2000