Rigid 6/spl times/6 parallel platform for precision 3-D micromanipulation: theory and design application

A new type of 6/spl times/6 parallel platform mechanism-designated a "rigid platform"-characterized by very high stiffness and a high degree of accuracy is described. Two new structural concepts are proposed for obtaining high stiffness and accuracy. 1) The joints between the changeable links and the platform and between the changeable links and the base are designed as welded joints. 2) Microactuators for controlled elongation of the legs use controlled longitudinal elastic deformations of the legs. Four possible approaches for analysis of the kinematics of this mechanism are described: infinitesimal kinematics of a classical platform and of a modified classical platform, the finite-elements method, and an identification procedure. Experimental investigations of a pilot setup of the proposed platform confirmed the predictions concerning the accuracy and stiffness of the proposed device.