This study details the development of an ultra-precision air-bearing stage that integrates real-time motion error measurement and compensation features. The motion errors addressed include horizontal and vertical straightness errors, as well as roll, pitch, and yaw errors. These errors are measured by an embedded system that incorporates five capacitive sensors and a reference mirror within the stage. A key advantage of this stage is its capability to perform real-time compensation using the internal measurement system and on-stage pneumatic regulators, eliminating the need for external measurement and compensation devices. Experimental results show a significant reduction in motion errors, with horizontal and vertical straightness errors decreasing from 3.09 and 1.95 μm to 0.29 and 0.25 μm, respectively. Additionally, roll, pitch, and yaw errors were reduced from 3.18, 3.45, and 4.93 arcsec to 0.35, 0.41, and 0.49 arcsec, respectively. These results clearly demonstrate the effectiveness of the proposed approach.

In ultra-precision processes, such as aerospace parts and precision mold machining, the accuracy of a feed drive system should be secured to achieve sufficient form accuracy. Dual-Servo stages, which compensate for multi-DOF motion errors, are being developed depending on the applied processes. This paper deals with the fine stage of a dual-servo stage to compensate for 6-DOF motion errors of a linear stage. The proposed fine stage measured 6-DOF errors of the linear stage motion with capacitive sensors, a reference mirror, and an optical encoder. It compensated for the errors using the flexure hinge mechanism with piezo actuators. The error equations and the inverse kinematics were derived to calculate the 6- DOF errors and displacements of piezo actuators for 6-DOF motions, respectively. Performance evaluation was implemented to verify feasibility of the developed fine stage of the fabricated dual-servo stage. Through the step response test of the fine stage, compensation resolutions for the translational and the rotational motion were confirmed to be less than 10 nm and 1/3 arcsec, respectively. The 6-DOF motion errors in the verification test were reduced by 73% on average.

In this research, a precise on-machine line-profile measuring system that compensates for the motion-error from the linear-guide, which can influence the accuracy of the measurement of the profile was developed. For this purpose, the principle of measuring the system model was used to analyze the compensating motion error component for line-profile and 3 types of MPES method (Integration-Method, the Fourier-Model-Method, and the Sequential-Method). The multi-probe-error-separation-method (MPES) was applied to calculate the motion-error, which in turn was used to compensate for the measured linear-profile of the specimen. Lastly, the simulation conditions involving a multi-probe measurement system consisting of a reference-artifact, capacitive-sensor, and three displacement-sensors were designed and Monte-Carlo simulation was implemented for the evaluation of the 3 types of MPES method. Also, the simulation results obtained from the conventional measuring system and the proposed system were compared for the verification of the performance of the latter. Consequently, efficient compensation of the motion error appeared as possible and the applicability of the multi-probe measurement system was confirmed.