Geometric-error analysis of three-axis machine tools using displacement information relative to single location

摘要

To achieve rapid and automatic analysis of linear-positioning and squareness errors of three-axis machines, a method requiring a single tracking interferometer placed at a single location is proposed. A kinematic model of a three-axis machine was first devised. Subsequently, an optimization algorithm was applied to solve the inverse kinematic problem by defining reasonable initial and boundary conditions. Simulation parameters included geometric errors of the machine, instrument locations, and repeatability of measurement results (definition derived from the ISO 230-1 standard). Results obtained via simulations demonstrate that considering a repeatability of 4 μm, the maximum differences in linear-positioning and squareness are observed to be -0.9 μm/m and 0.2 arcs, respectively, whereas the corresponding maximum standard deviations are 0.28 μm/m and 0.01 arcs. The method has further been verified using a coordinate-measuring machine. Experimental results demonstrate that analyzed parameters show reasonable agreement with simulation results, wherein maximum differences in linear positioning and squareness errors were observed to be 0.7 μm/m and 0.3 arcs, respectively. The total measuring time of a thrice-divided spatial grid was approximately 10 min. The results of the study demonstrate the feasibility of the proposed method in rapidly analyzing geometric errors In three-axis machines.