Self-calibration interferometric stitching test method for cylindrical surfaces

Abstract

The surface figure accuracy requirement of cylindrical surfaces widely used in rotors of gyroscope, spindles of ultra-precision machine tools and high-energy laser systems is nearly 0.1 µm. Cylindricity measuring instrument that obtains 1-D profile result cannot be utilized for deterministic figuring methods. Interferometric stitching test for cylindrical surfaces utilizes a CGH of which the system error will accumulated to unacceptable extent for large aperture/angular aperture that require many subapertures. To this end, a self-calibration interferometric stitching method for cylindrical surfaces is proposed. The mathematical model of cylindrical surface figure and the completeness condition of self-calibration stitching test of cylindrical surfaces were analyzed theoretically. The effects of shear/stitching motion error and the subapertures lattice on the self-calibration test results were analyzed. Further, a self-calibration interferometric stitching algorithm that can theoretically recover all the necessary components of the system error for testing cylindrical surfaces was proposed. Simulations and experiments on a shaft were conducted to validate the feasibility.