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To improve the work performance of a 2;d mirror gimbal for the lunar;based telescope, the thermal;structural coupled analysis was carried out, and the analysis results were verified by thermal and onboard tests. according to the given input conditions, thermal loads and the thermal boundary, the finite element model was established to calculate the temperature fields of the mirror gimbal and main heating components. through inputting the temperature loads, preloads and the boundary conditions into the finite element model, the thermal deformation and stress of the u;shape structure, precision moving shafting systems and the worm gears were obtained. then, the expressions of friction moment were derived, and analytical data were used to the expressions to achieve the friction moment of shafting systems. on the basis of the friction moment, a proper moment motor was chosen. after calculation, the results show that the left shafting system has a larger friction moment at the low temperature condition of ;25, and the maximal one is up to 14.163 n·mm; while the friction moment is smaller under high temperature condition 55, and the maximal one is 4.796 n·mm. the results also show friction moment of the azimuth shafting systems at a low temperature condition of ;25 is 16.45 n·mm. moreover, the vertical shaft system shows its friction moment to be 16.45 n·mm at the low temperature condition of ;25, while it is zero at the high temperature condition because of shafting system unloading. the results indicate the reflection mirror gimbal works well between ;25 to 55. finally, the thermal and onboard tests were carried out to demonstrate the rationality and validity of the analysis results. © 2016, science press. all right reserved.

A new type nanometer Coordinate Measuring Machine(CMM) stage which meets the Abbe principle in three-dimensional directions is proposed to avoid the Abbe error in conventional CMMs and reduce the guide motion error that influences on the nano-CMM measurement uncertainty.The stage can move in three dimensional directions and its x guide and y guide are in a coplanar structure.The three measuring lines of the stage are orthogonal and intersect at one point which coincides with the center of a probe.Moreover,the measuring lines of x measurement system and y measurement system are coplanar with the plane of the xy stage.According to the characteristics of this stage,the impacts of various errors on the stage are analyzed,the main source errors to the measurement uncertainty are given and new correction methods for those errors are proposed.Finally,two pieces of first gauge block are measured on the developed stage.Measurement results show that the standard deviation of flatness error of first gauge block working surface is 11 nm,and that of step height is about 21 nm and the difference between the average of step heights and the calibrated value is about 1 nm.The theoretical analysis and experiment show that the nano-CMM avoids the impact of various error sources,especially the impact of Abbe error,and can be used in high-precision three-dimensional measurement.