Analysis and design of a novel 4-axis hybrid machine tool based on a 2-DOF parallel mechanism

Based on the characters of simple mechanics analysis, calibration and structure, the parallel or hybrid machine tool of less than 6 degrees of freedom (DOF) become one of the development trends of manufacturing equipment. In this paper, a planar two degrees of freedom parallel mechanism is investigated. Closed-form solutions are developed for both the inverse and direct kinematics. The singularity and workspace for the mechanism are analyzed systematically. The velocity output ratio and the global velocity output ratio about the mechanism are defined. And the dimensional design based on workspace and velocity indices is presented. In the end, a concept design for a new 4-axis hybrid machine tool is proposed.