The application of a regularization method to the estimation of geometric errors of a three-axis machine tool using a double ball bar

Abstract

Geometric accuracy is crucially important for machine tools. Identification of geometric errors, especially position-dependent geometric errors, is still a challenging issue. This paper presents a systematic and fast approach to identify the geometric error components of a precision machine tool using double ball bar (DBB). The approach can be implemented in three steps: (1) polynomial based error modeling that relates the DBB radius error directly to the geometric error parameters of machine tool; (2) spatial measurement trajectory planning with a single installation of DBB in order to avoid producing extra setup errors; (3) error identification with regularization method that can solve the ill-posed identification problem effectively. Simulations and experiments show the accuracy and effectiveness of the proposed identification approach. The results of the DBB test show that, utilizing the proposed identification method, the roundness errors of the three circular paths in xy-, yz- and xz-plane are reduced from 27.3 μm, 20.7 μm and 24.1 μm to 9.2 μm, 12.3 μm and 7.8 μm, respectively, with error compensation.