| In order to satisfy the requirements of different precise manufacture and measurement, the precise platforms are being developed by many countries in the world and made great progress. As a kind of 2D platform, X-Y stages with metrology, long rang and high precise own great potential. For these requirements, the core contents of this paper involve in two aspects: measurement of 2D displacements and structure and drive of precise platform. Main research contents and creative points in the dissertation are as follows: The measurement principle and methods of the cross grating are introduced. The optical layout of metrology system is designed based on grating vector equations that are more suitable for analyzing diffraction light beams. Mathematical models between grating deflection and light beams'change.is built up and with help of computer simulation, the relation of interference fringes and grating's direction is demostrated. According to metrological characteristics of diffraction grating, the measurement error models are built up and the equations between installation and measurement errors of grating are deduced. Effective range of detection signal is analyzed and proposes a means of ellipse fit that revises and compensates measurement result to improve measurement precision. Considering the interference fringes produced by diffraction grating have inferior quality, the measurement's key technologies are the methods of fringes photoelectric detection and process. Two new methods of layout of photoelectirc cells, including zero space difference cells and 'ç”°'shape, are proposed to receive firnges'signal, and achived a good effect. The integration method is applied to analyze the amplitude and phase difference of signal and the theoretical model between the amplitude, phase differenc and width, rotation angle of fringes are built up. Comparing to the traditional direct phase analysis, the integration one can reflect the relation between signal and light intensity, receiving area more accurately. With application of fringes'noise model, the SNR (signal noise ratio) analysis for new and traditional layout of photoelectric cells testifies the new ones own higher SNR and can dramatically restrain DC adrift. Ellipse fit algorithm is presentd to process the interference fringes by linear CCD. The principle and realization of the algorithm are explained. The computation results for simulation fringes show that this method owns high precision, high speed of computation and high resistance to noise. The plane cross diffraction grating is used as measurement standard, the 2D platform with mutual measurement and base level is designed and developed, and it has been granted a pantent No.02138704.4. The stages adopt alternate servo motor and piezoelectric actuator to realize coarse and fine positioning. The coarse drive uses point touching mode with flexibility and magnetism, and the objective table touched tightly on a planar wafer to enhance its motion flatness. The target table is linked together with plane grating, and plane grating is placed to the below of platform to record its displacements. The structure and driving errors are analyzed and some static parameters are computed. These provided basis of dynamic analysis. Some circuits are designed and realized. They are the PZT power supply, photoelecric transform and a multi-function circuit using counting interference fringes'number and driving motor etc. On basis of software and hardware developed by ourselve, experiments have studied on static and dynamic characteristics. According to different properties of different parts composed of driven system including coarse and fine actuators, the dynamic test methods are designed, and the dynamic parameters are resolved by using different algorithms. On basis of comparison measurement results of double-frequency laser interference and grating, the measurement precision and potential application of the cross diffraction grating is disscussed.
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