A machine tool global static stiffness modeling method based on layer-by-layer decoupling of overall machine deformation

Abstract

This invention discloses a method for modeling the global static stiffness of a machine tool based on layer-by-layer decoupling of overall deformation. The method includes: decoupling the overall deformation of the machine tool layer by layer into tool chain deformation and workpiece chain deformation, and further decomposing these into deformations at several equivalent load points; constructing a surrogate model by performing finite element analysis on discrete experimental points and combining it with Kriging interpolation to establish a parametric compliance response surface model with the travel of each axis as input; synthesizing the compliance matrices of the drive system and the total compliance matrix of the motion system based on the actual series and parallel connections between components; and applying coordinate transformation matrices, force transformation matrices, and point transformation matrices to transfer and aggregate the deformations at each equivalent load point, ultimately synthesizing the overall compliance matrix of the entire machine tool, thereby constructing a global static stiffness space characterizing the tool tip relative to the workpiece. This invention features high computational efficiency and good model fidelity, and can analyze the static stiffness characteristics of a machine tool in any posture throughout the entire workspace.

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