Stiffness of 5-axis machines with serial, parallel, and hybrid kinematics: Evaluation and comparison

Introduction of parallel kinematics mechanisms in structures of modern machine tools results in resumed development and investigation of stiffness performance indexes. In this paper, a new stiffness-related engineering index – minimum collinear stiffness value (CSV) – is applied for stiffness evaluation of machine tools with different kinematics types. The evaluation embraces both local stiffness values in a given configuration and global stiffness features over all workspace. A dimensionless form is entered as the ratio of the CSV to the stiffness value of a single actuator. Stiffness features of 5-axis machines with serial, parallel, and tripod-based hybrid kinematics are simulated using the developed approach.