【作者】 张俊杰；

【导师】 叶声华； 孙方金；

【作者基本信息】 天津大学 ， 测试计量技术及仪器， 2010， 博士

【摘要】 自准直仪经历了目视式、光电指零式和数显式三个发展阶段,其中光电指零式的技术进步点是采用了模拟量光电对线,其读数方式仍为目视、手动,性能并没有质的飞跃,因此只是个过渡阶段。当前作为通用计量器具的数显式自准直仪的发展方向为提高分辨力与示值稳定性。高分辨力是高准确度的保证,高稳定性是高分辨力的保证。而自准直技术的发展趋势是扩大应用范围,由静态测量向动态测量发展,由通用计量器具向专用设备发展,以满足各行业的特殊需求。依据对自准直仪国内外情况和发展趋势的分析,确定论文以研究自准直仪分辨力和示值稳定性为中心,对相关问题进行机理分析、措施探讨和实验验证。提高分辨力采用了独特的方法:在自准直光路的基础上增加光学放大,从而大幅度提高了当量焦距,在国内外首次把光学放大应用于数显式自准直仪,其难度为:对自准直像的位移量进行放大的同时,把准直物镜的像差和气流影响的跳字量也进行了放大,为此,采用了相对孔径较小的准直物镜,把“畸变”作为消减的主要像差,并采取多种减小跳字量的措施。数显式自准直仪的示值稳定性分为瞬时稳定性即跳字量与短期稳定性即漂移,瞬时稳定性以可分为本机跳字量(内因)及气流引起跳字(外因),外因跳字是常见又难办的现象,形成机理是空气的折射率随温度、压强和湿度而变化,气流使其折射率为变数,按折射定律,反射光产生角度变化由自准直仪感受产生跳字。加隔离罩是简单、有效、常用的方法,但是要求罩内的设备具有自动或遥控功能,否则会影响减小气流跳字量的效果,为此对不能加隔离罩的情况提出了“差动反光镜”法:当一块固定反光镜、一块运动反光镜安装在同一轴线上、反光面积相同时受气流的影响相近,相减后可减小气流跳字量。采用正弦臂差动式激光小角度校准装置作为检测设备,对自准直仪进行综合定标,并用分段线性补偿对示值误差进行补偿,有效地提高了自准直仪的准确度。在研究分辨力和示值稳定性的基础上研制了高分辨力数显式自准直仪,最小显示值0.001",分辨力<0.005",在±10"测量范围内示值误差为±0.01",除总的测量范围较小外,达到了当前国际上最高档的德国M?LLER公司HR型自准直仪的水平。更多还原

【Abstract】 The evolution of autocollimator experienced visual type stage, photoelectric null-indication type stage and digital display type stage. The technological advance of photoelectric null-indication type stage was the usage of analog photoelectric line-to-line type, which means the way reading is still visual and manual. There was no qualitative leap in the stage and it is only a transitional stage. The digital display type autocollimator is used as a universal measuring instrument. The direction of evolution is to improve the resolution and the indicating stability. High stability guarantees high resolution, which ensures high accuracy. The autocollimator technology trend is to expand the scope of application to meet the special needs of various industries, such as measuring from the static to dynamic measurement, and from common measuring instruments to the special equipment. Based on an autocollimator situation at home and abroad and development trend analysis, the subject of the thesis is meaning to study the resolution and indicating stability of autocollimator, analyze relevant issues, explore measures and experiment.A unique approach is adopted to improve the resolution: an optical zoom path is added on the optical path of autocollimator, which substantially increased the equivalent focal length. The optical zoom path is added on digital type autocollimator at home and abroad for the first time. The difficulty is: the shift of autocollimating image is enlarged, while the aberrations of the collimating lens and the rising space affected are also enlarged. So the collimating lenses with relatively small aperture are used. The "distortion" as a major aberration is reduced, and various measures are taken to reduce the rising space.The indicating stability of the digital display type autocollimator includes the transient indicating stability (the rising space) and the short-term indicating stability (the drift). The transient indicating stability can be divided into the native rising space (internal) and the rising space caused by airflow (external). External causes are common but difficult to handle. The mechanism of the rising space is that the refractive index of air changes with the change of temperature, pressure and humidity. So the refractive index is variable for the air flow. The rising space is produced by the changes of reflection angle which affects the autocollimator, according to law of refraction. Using isolating shield is simple, effective, common method, but the equipment in the shield requires automatic or remote controlling. Otherwise the effect of reducing the rising space for the air flow will be affected. So "differential mirror" method is proposed to cover the situation where the shield can not be used. If a fixed mirror and a movable mirror are installed in accordance with the same axis and the same reflecting area, the effect of the air flow is similar. Then the rising space for the air flow can be reduced by subtracting.Differential sine bar small angle laser measurement instrument as standard equipment is used to comprehensively calibrate the autocollimator. A piecewise linear compensation is used to compensate indicating error, which improves the accuracy of the autocollimator effectively.A high resolution digital display type autocollimator is developed based on the study of resolution and indicating stability. The minimum display value is 0.001", resolution <0.005", the indicating error in measuring range of±10" is±0.01". The autocollimator reaches the current world’s most high-end level like HR-type autocollimator made by M?LLER Company in German; except the total measurement range is smaller.更多还原