Error Analysis And Optimization Of Three-Dimensional Absolute Displacement Measurement System Based On Point-Diffraction Interferometry

A three-dimensional absolute displacement measurement system based on point-diffraction interferometry(ADM-PDI)has been proposed,as a portable and quick way to measure in this paper.On the premise of the system being realized,some error analysis and optimization method for this system has been proposed.Firstly,a modified mathematical model of the ADM-PDI has been proposed to upgrade the computational efficiency of the system,because the modified mathematical model classifies the 6 unknowns into 3 group.The layout and the principle of the hardware of ADM-PDI has been presented.And a new point diffraction fiber with a submicron-aperture(SMA fiber)and its production method have been proposed.Secondly,many algorithms has been introduced to solve the mathematical model.Newton's method and Levenberg-Marquardt least squares optimization method,which are nonlinear iterative algorithm,are low success rate and low efficiency in the actual operation with large noise and large numbers of sample points.A particle swarm optimization(PSO)with a modified quick search method has been presented to solve this problem(QS-PSO).The QS-PSO greatly improve computational efficiency and convergence speed by nonlinear growing the equation numbers.Thirdly,the finite difference time domain(FDTD)simulation method and calibration experiment method has been presented to estimate the point-diffraction wavefront error of the SMA fiber.The basic theory of point-diffraction wavefront retrieval is based on differential Zemike polynomials fitting method and the rigorous model for systematic error calibration.Fourthly,the error in the AMD-PDI system has been analyzed.The size of the error has been estimated by modeling,simulation,analysis and compound all of the error term.Finally,the hardware platform of this system has been set up,and the console center software based on MFC has been compiled at the same time.The calibration SMA fiber experiment method and proposed ADM-PDI system has been proved to be effective.The work has been summarized and prospected.