Extension of Machine Tool Kinematic Model to Direction- and
Velocity-dependent Error Motions and Their Cross-talk
Soichi Ibaraki, Mashu Hiruya, Isao Oshita, Kazuya Fujimoto
Abstract
The conventional volumetric error compensation for a machine tool is based on the machine's kinematic model, which kinematically formulates the tool center point (TCP) position based on the assumption of rig-id-body motion. Particularly in large-sized machine tools, error motions that do not satisfy this rigid-body assumption may have a significant impact on the machine's overall volumetric accuracy. This study pro-poses a new kinematic model including the influence of three factors; 1) direction- and 2) veloci-ty-dependent error motions, and 3) quasi-static cross-talk between the axes. The paper presents a scheme to assess all the error motions by using a two-dimensional digital scale (cross grid encoder). It is experimentally demonstrated on a large-sized horizontal machine tool.
Keywords: Machine tool, Volumetric accuracy, Measurement, Two-dimensional digital scale, Kinematic model
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