Structural parameter optimization of a crossbar parallel machine tool

Abstract

Increasing workspace and improving dexterity are important taskes for the design of parallel machine tool. On the basis of inverse kinematics, workspace of the crossbar parallel machine tool with constraints was obtained via three-dimensional search method. New Jacobian matrix of the machine was also deduced by using the natural coordinate method. Dexterity distribution of the machine was acquired as well based on the workspace and new Jacobian matrix. Then, the impacts of structural parameters on workspace and global dexterity index were analyzed, then least square method was applied to curve fitting and the optimization of these structural parameters were carried out by introducing workspace value index and global dexterity index as the global optimization goals. Compared with the original data, each of them increases by 0.40 and 0.26 times respectively, achieving the aim of mechanism optimization.