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Three Degree of Freedom, Two Loop Spatial Manipulators

P. Gervasi, M. Husty (MU-Leoben), P.J. Zsombor-Murray 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 begun to investigate a class of three degree of freedom platform manipulator with three R*-S-R legs in roughly octahedral configuration with (*) indicating the actuated, basal joint. This manipulator offers attractive solution for tasks requiring reduced mobility. Furthermore, their kinematic analysis is quite simple and by adding a second actuated joint near the base in each leg, say R*-P*-S-R, a six degree of freedom platform, whose direct kinematic equations are identical to those formulated for the three legged, three degree of freedom, R*-S-R variety, is obtained. This architecture should lead to more economical and easily controlable vehicle simulator designs than existing ones based on the conventional six U-P*-S legged Stewart-Gough platform

Thierry Baron
Mon Apr 7 12:54:24 EDT 1997