AN ADAPTIVE ERROR-CORRECTION METHOD USING FEATURE-BASED ANALYSIS TECHNIQUES FOR MACHINE PERFORMANCE IMPROVEMENT .1. THEORY DERIVATION

An adaptive error correction method using a feature-based analysis tec hnique for improving the accuracy of CNC machine tools is presented. T he method described in this paper emphasizes the integration of the pr ocess-intermittent gauging and analysis techniques with information fr om pre-process characterization and post-process inspection. The propo sed method utilizes the information from pre-process characterization, process-intermittent gauging, and post-process inspection to improve machine performance automatically. Algorithms are derived for analyzin g the post-process and process-intermittent inspection data to decoupl e process-related errors from machine errors and for identifying the r esidual systematic errors. A feature-based analysis technique is devel oped to relate the dimensional and form errors of manufactured feature s to the systematic machine tool errors. Inverse kinematics and statis tical methods are used to identify and characterize the contribution o f each residual error component on imperfect features. Also a recursiv e tuning algorithm is developed for fine tuning the geometric-thermal model.