Analysis of 5-DOF Motion Errors Influenced by the Guide Rails of an Aerostatic Linear Motion Stage

This paper presents an estimation method for five-degrees-of-freedom (5-DOF) motion errors, which are influenced by the profiles of guide rails of an aerostatic linear motion stage. The transfer function, which is the relationship between the magnitude of the rail form error and the reaction force of a bearing pad, was introduced to simplify and systematize the estimation of the motion errors. The motion errors were calculated from the equilibrium conditions for the forces and moments of the stage using the geometrical relationships between the bearing pads, the transfer function, and rail form errors. Experimental verification of the rail form error was carried out using a porous aerostatic linear motion stage and the mixed sequential two-probe method. The aerostatic feed table of the experimental stage, on which sensors were mounted, was also used as the feed unit for measuring the rail profiles. The 5-DOF motion errors were estimated from the measured rail form errors using the transfer function method. The estimated results were in good agreement with the experiments.