Kinematic Analysis of a Four Degreed-of-Freedoms Hybrid Machine Tool

On one hand, parallel machine tool enjoys many advantages over conventional serial counterpart, on the other hand, it also suffers from the disadvantages of coupled position and orientation, difficulty in kinematic modeling, strict requirements for components and difficulty in manufacturing of the spherical joint adopted in some limbs. Hybrid mechanism, however, will serve the turn in some cases. By using a three degree-of-freedoms parallel mechanism and a slide worktable which will fulfill one movement, a novel four degree-of-freedoms hybrid machine tool is put forward. The kinematic solutions are analyzed and closed-form kinematic solutions are given. The methods and theories adopted here can be used for design of other types of hybrid machine tools.