Automatic straightness measurement of a linear guide using a real-time straightness self-compensating scanning stage

Abstract In this paper a method is developed for straightness measurement of a linear guide by using a straightness self-compensating stage with an optical straightness measuring system, an eddy current sensor, and a cross-roller type compensation stage. Both the compensation stage and the optical straightness system were set up on a scanning stage to measure the straightness error of the scanning stage. The measured straightness error was fed back to the control system to compensate directly in real time. Thus, straightness of a linear guide without the added straightness error of the scanning stage could be measured. The Hewlett Packard laser straightness calibration system was used to verify the real-time compensated results. Straightness error of the scanning stage was compensated from the worst straightness error of 20 μm/150 mm to 0.9 μm/150 mm. The eddy current sensor measured straightness of the linear guide and the measured result matched the result obtained by the coordinate measuring machine.