Simultaneous Measurement Methods Research Of Angle And Displacement Based On Optical Path Difference

During high technological and industrial development in modern time,high-precision two-dimensional micro-angular displacement and line displacementtracking measurement has important theoretical and practical significance, especially inmany areas of precision test and measurement. Therefore, the paper combined withMichelson interferometry method to design a measurement system based on the angle anddisplacement of the optical path difference modulation synchronization. The paper hascarried out a systematic analysis experimental form the aspects as interference principle,the modulation of the optical path, photoelectric signal conversion, and hardware andsoftware implementation. The concrete contents are as follows:First, in principle based on the Michelson interferometer, through the analysis ofinterference fringes shape and the light angle, the simulation analysis of the relationshipbetween fringes shape and the measurement two-dimensional deflection angle has beenrealized, verifying the theoretical calculation relationship of the two-dimensionalmicro-angle and stripe shape, meanwhile established in this paper in order to obtainaccurate interference fringe shape information as the core research purposes.Secondly, a method of modulating optical-path differences through a optical wedgeis put forward. The drive circuit has been designed which is utilizing voice coil motordriving a wedge, and the motion equation of interference fringes is obtained by opticaltheoretical analysis, including the solution of the transfer coefficient of transmission viathe flexible hinge, then to make the experimental results analysis for the dynamiccharacteristics of the voice coil motor at the same time.Thirdly, in the analysis of experimental results of the wedge modulating theoptical-path difference, using the PZT directly modulating the optical-path to improveprogram design. Simulation analysis each quadrant phase-difference of circularphotocell compared to Tian-shaped photoelectric tube, which is used to receive motionstripes, then coming to phase change information of the fringe. Through real-timeacquisition of PZT linearity characteristic curve analysis, the improvement of theaccuracy of the measurement results has been predicted by the program improved.Fourthly, design analog circuit to obtain adjacent quadrant phase-difference ofinterference fringes, and obtain errors of hardware circuit itself introducing to throughthe analysis of experimental data, so to obtain the realization of fringe phase-differenceby the way of software. The thinking of software to obtain phase-difference is using theclassic ellipse fitting algorithm to obtain the two signals which are independent offrequency difference. Handling the details of the simultaneous acquisition and signalfiltering, the experimental results show that it access to good effect for obtainingphase-difference.Fifthly, under the platform of two-dimensional angular displacement measurementsystem, using the original Michelson displacement measurement principle to achievethe simultaneous measurement of linear displacement. The four segments of the FPGAhardware logic circuits was used to achieve the improvement of measurement accuracy.Finally, many simultaneous measurement experiments comparison have been donebetween the measurement system of this paper and commercial photoelectricautocollimator ELCOMAT3000made in German MOLLER company and MJS5Cmodels of dual-frequency laser interferometer made in Chengdu Tool Research Institute, then obtaining the accuracy of the measuring system and stability, giving the erroranalysis of the measurement system combined with the theory and reality environment.