Optimization of a crossbar parallel machine tool based on workspace and dexterity

Abstract

Increasing workspace and improving dexterity are important tasks for the design of parallel machine tools. The workspace of a crossbar parallel machine tool with constraints is obtained by using a 3D search method based on inverse kinematics. The new Jacobian matrix of the machine is also derived by using the natural coordinate method. Dexterity distribution of the machine tool is obtained on the basis of the workspace and the new Jacobian matrix. Influences of the structural parameters on the workspace volume index (WVI) and global dexterity index (GDI) are analyzed. Structural optimization is conducted by treating the WVI and GDI as the global optimization goals. Unlike the initial data, the optimized results increased by 0.43 and 0.34 times.

Dimensional Synthesis of Kinematic Dexterity and Workspace for 3-DOF Parallel Manipulator

“…Condition number of Jacobian matrix at the point is used to measure the dexterity [17], which can be calculated as follows:…”

“…Dexterity is one of the most important performances to evaluate the parallel kinematic machines (PKM) good or bad [5]- [7], which reflects on the dexterous capability over the task workspace. Meanwhile, dimensional synthesis aims to improve the performance of a mechanical robotic system and is an important procedure of parallel manipulators from their schematic diagram to the structural design, in which two challenging issues associated with kinematic performance index and optimal design method are involved [8].…”

Workspace Performance Investigation of a Multi-DOF Parallel Robot Manipulator

“…Dexterity is one of the most important performances of parallel kinematic machines. Meanwhile, dimensional optimization is to improve the performance of a mechanical robotic system and is an important procedure of parallel manipulators from their schematic diagram to the structural design, in which two challenging issues associated with kinematic performance index and optimal design method are involved [9]. Therefore, it is quite necessary to perform the dexterity analysis and to conduct optimal design of the parallel kinematic machines in the early design stage.…”