Motion error estimation of slide table on the consideration of guide parallelism and pad deflection

This paper presents a motion error estimation method for a slide table using a transfer function method, which calculates motion errors due to the rail straightness of a slide guide stage. The proposed transfer function method uses a new reaction force-moment model with a double spring system to consider the effect of the reaction moment resulting from a pad pitch error. This paper also proposes a new straightness measurement method, which takes guideway parallelism error in account. Guideway straightness data were measured using a stage suspended by porous air pads. Over a working distance of 1,620 mm, stage motion errors were measured each 20 mm. Measured straightness data were used as input to the motion error analysis of the slide guide table. The estimated motion errors were compared with both the measured data and the estimated motion errors by the existing transfer function method. The estimated results agreed with the experiment results. Moreover, the estimation errors of pitch and yaw of the proposed reaction force-moment model were smaller than those of the existing reaction force-moment model.