Hybrid optical measurement system for evaluation of precision two-dimensional planar stages

Measurement of six-degree-of-freedom geometric errors of a translation stage using three absolute position encoders

“…where, ∆x Si , ∆y Si , and ∆z Si represent the variations of the ideal axial positions of the PEBS from the initial position at each measurement point of the ith encoder (P i ), which are represented in the fixed coordinate system. Since precision translation stages usually have small geometric errors, the 6-DOF posture variations of the moving platform at the central measurement point can be calculated by applying the encoder readout variations to equations ( 4)- (9), which are derived from geometric relations. ∆y Ec = ∆y E1 + ∆y E2 + 2∆y E3 4…”

“…where L is the measured displacement. The reference geometric errors of the other axes were evaluated by re-configuring two hybrid sensor modules [9] for the measurement of straightness errors of horizontal and vertical axes, respectively. Since the sensor module consists of a scanning interferometer and an autocollimator part, it can measure the surface profile of a reference mirror and two-axis angular motions, simultaneously.…”

“…This adaptability is crucial to overcome challenges such as restricted installation space and potential interference with other components of the stage system. Furthermore, if these measuring instruments can accurately measure multiple key performance indices using a single configuration, the efficiency of on-site evaluations would be further enhanced [3][4][5][6][7][8][9][10].…”

“…Furthermore, a complex analysis or compensation model for the imperfections in the reflectors was necessary. A hybrid measurement system was developed to simultaneously evaluate the straightness error of a reference mirror and multiaxis motion errors of a two-dimensional (2D) stage [9], but its applicability is limited to special configurations due to the requirement of an L-shaped mirror. A commercial laser interferometer is available, capable of measuring the motion of a precision stage in up to six axes by combining three-axis laser interferometer and other optical sensors [10], but its extensive use is constrained by its high cost.…”

An Autocollimator Axial Measurement Method Based on the Strapdown Inertial Navigation System

“…At present, precision measurement is usually not limited to one kind of equipment, and multi-device cooperative work is one of the hot topics in current research [ 24 , 25 ]. With the improvement of the accuracy of laser gyro, fiber-optic gyro, and micro-electromechanical system (MEMS) inertial guidance technology, as well as the decrease in the cost and volume, inertial guidance has been employed in a large number of applications for the solution of position and navigation under multi-sensors.…”