Closed form solution of forward position analysis for a 6-DOF 3-PPSP parallel mechanism of general geometry

A closed-form solution of both forward and reverse position analyses for a 6 degree-of-freedom parallel mechanism of general geometry is derived. The mechanism consists of a top plate, a base, three PPSP serial subchains connecting these two plates. In the position analysis, it is assumed that the first two prismatic joints of each of the three serial subchains are actuated and that the last passive prismatic joint of each of the three subchains are constrained to move in parallel to the top plate, and axes of those three prismatic joints intersect at a common point. Then, the workspace variations of mechanism with respect to joint limitations are investigated. It is concluded that the mechanism studied in this paper has a great advantage over the other parallel mechanism in aspects of analytical simplicity