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本文讨论用棱镜干涉仪(Twyman-Green 干涉仪)精确测量角度的原理、公式、方法及精度,并举出实例进行分析。讨论是以分析锥体棱镜(角反射器)两面角(直角)测量为例,然后推广到测量屋脊棱镜屋脊角,长方体的直角等等。这是一种既方便而又精确的方法。 相似文献
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讨论了插齿刀的几何角度对其耐用度与构形误差的影响,分析了在磨齿机上对插齿刀侧后刀面进行特殊刃磨以减小插齿刀构形误差的工艺原理,在显著提高刀具构形精度的同时通过增大刀具几何角度提高了其耐用度并通过了试验验证。 相似文献
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抛物面反射器的表面精度是衡量天线制造水平的重要指标,也是影响天线增益的主要因素。在相同口径及相同表面精度条件下,工作频率愈高,表面误差对天线的增益影响愈明显。随着更高频率的开发及启用,对反射器表面制造精度的要求也不断提高。在实际设计中,我们可以由给定的增益折减系数来分配反射器表面误差值并提供制造、检验依据,采用 相似文献
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激光跟踪测量系统跟踪转镜的误差分析 总被引:4,自引:1,他引:3
激光跟踪测量系统是目前最新型的便携式空间大尺寸坐标测量系统,可对空间运动目标进行跟踪并实时测量其三维空间坐标,具有精度高、范围大、实时快速等特点。然而,激光跟踪测量系统中跟踪转镜的几何误差严重影响了其测量精度;所以激光跟踪测量系统在使用前必须对其进行建模和误差分析。在全面研究了激光跟踪测量系统结构和工作原理的基础上,建立了系统运动学模型和跟踪转镜中心偏移数学模型。详细分析了系统测量中基点位置变动误差、转镜跟踪目标反射器跟踪误差和转镜反射面与激光束不垂直误差等。结果表明跟踪转镜中心偏移、回转轴不对称、基点位置变动、光束反射点与基点不重合是导致测量误差的主要原因。因此,在跟踪转镜结构设计中,为保证激光束反射点与基点位置重合及转镜旋转跟踪目标反射器时基点空间位置保持不变,应尽量减少跟踪转镜旋转点与镜面之间的距离。 相似文献
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王明 《机械工人(冷加工)》1983,(4)
五、空间角度的误差分析前面的讨论只解决了夹具角度名义值的计算。但在实际工作中某些零件图中所给出的角度公差较严,这时就要进一步解决夹具角度调整的精度问题。即是解决夹具的θ和φ角按照什么精度调整能满足图纸要求。为此,有必要对夹具所产生的角度误差进行定量分析。 相似文献
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Determination of the reflector type from an image reconstructed using echo signals measured with ultrasonic antenna arrays 总被引:1,自引:0,他引:1
E. G. Bazulin 《Russian Journal of Nondestructive Testing》2014,50(3):141-149
The application of the digital image focusing (DFA) method to the determination of the types of detected reflectors is considered. For this purpose two antenna arrays (AAs) are used, which are placed on opposite sides of the reflector and using which echo signals are recorded in three acoustic channels in the double-scanning mode. The first and second acoustic channels transmit and receive echo signals using the first and second AA, respectively, and the third channel is tuned so that the first AA transmits pulses and the second AA receives echo signals. Using signals in each channel, many partial images can be reconstructed in a common coordinate system according to different acoustic schemes with allowance for both multiple reflections from irregular boundaries of a tested object and effects of transformation of the wave types. Combining partial images makes it possible to obtain a high-quality image, in which the entire boundary of the reflector is seen and using which an attempt to automate the procedure of evaluating the reflector size and determining its type was made. Such an approach allows one to reduce the subjective influence of an operator on the testing results. It is shown that in order to increase the image resolution, the spectrum of echo signals can be extrapolated by the spectrum splitting method jointly with the construction of an AR model of their spectrum. The results of model experiments that confirm the possibility of determining the reflector type are presented. 相似文献
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《Measurement》2014
A simple and fire safe gasoline level sensor has been designed based on displacement sensor using fiber coupler. The sensing principle is to detect displacement of reflector, which is attached to membrane (reflector displacement device), due to the change of gasoline hydrostatic pressure. The displacement of reflector can be detected using fiber coupler from the change of optical power light reflected by the reflector. Three kinds of reflector displacement device used in this experiment are one-layer, two-layer, and three-layer membrane. The experimental results are 0–180 cm of dynamic range, 100–140 cm of linear range, 3.2 mV/cm of sensitivity, and 0.6 cm of resolution for reflector displacement device with one-layer membrane for emptying the tank process. The hysteresis data for emptying and filling the tank process yields the mean of difference 20% for one-layer membrane. 相似文献
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A simple mirror holder which permits the use of locally damaged laser morrors by allowing the undamaged areas of the reflector to be aligned along the laser optic axis is described. The mirror holder has an eccentric step for housing the mirror and a concentric aperture through which the undamaged surface of the reflector is utilised. By varying the eccentricity and by rotating the mirror inside the step the entire surface area of the reflector can be used successively. 相似文献
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针对传统固体反射面机构主反射面型面精度和收拢率较低的问题,设计了一种可展开固体反射面机构。首先,提出4种固体反射面机构可展单元构型并对其机构自由度进行分析,对比分析构型方案优缺点确定构型方案4作为可展单元基础构型,并对其结构和展开原理进行详细设计。通过D-H坐标变换建立该机构可展单元的运动学模型,根据几何约束条件建立机构位置矢量方程,利用向量封闭投影法解出各回转角间的关系,结合MATLAB软件编程对机构的位置、速度和加速度进行分析。应用ADAMS软件建立机构仿真模型,验证了机构运动学分析的正确性。最后根据机构中回转角的限制条件和结构尺寸关系,分析回转角和结构尺寸对可展开固体反射面机构收拢率的影响,确定2.2m可展开固体反射面机构的回转角和旋转角分别为78°和30°,中心圆盘半径、铰支座一孔纵向尺寸、切换连杆横向尺寸、纵向尺寸分别为245,8,40,18mm,收拢率为0.326,从而为可展开固体反射面机构的设计提供参考。 相似文献
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Large reflector antennas are widely used in radars, satellite communication, radio astronomy, and so on. The rapid developments in these fields have created demands for development of better performance and higher surface accuracy. However, low accuracy and low efficiency are the common disadvantages for traditional panel alignment and adjustment. In order to improve the surface accuracy of large reflector antenna, a new method is presented to determinate panel adjustment values from far field pattern. Based on the method of Physical Optics (PO), the effect of panel facet displacement on radiation field value is derived. Then the linear system is constructed between panel adjustment vector and far field pattern. Using the method of Singular Value Decomposition (SVD), the adjustment value for all panel adjustors are obtained by solving the linear equations. An experiment is conducted on a 3.7 m reflector antenna with 12 segmented panels. The results of simulation and test are similar, which shows that the presented method is feasible. Moreover, the discussion about validation shows that the method can be used for many cases of reflector shape. The proposed research provides the instruction to adjust surface panels efficiently and accurately. 相似文献
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天线罩内空间紧凑,无法使用大型施工设备对大型部件进行施工改造。为了解决这一难题,文中研究了更换天线罩内大型天线副反射面及馈源的技术。提出了利用天线自身的俯仰运动进行吊装,并结合电葫芦长距离提升的优点,实现在天线罩内进行大型天线顶端吊装更换副反射面及馈源的施工方法。通过优化施工流程,分析关键位置的受力情况,形成了一套可行的施工方法,成功完成了大型副反射面及馈源的更换工作,且最终天线的各项结构和电气技术指标均满足要求。该方法首次应用于罩内大型天线副反射面及馈源的改造,可为后续该类大型天线的现场改造提供指导。 相似文献
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天线反射面板的成形方法对面板精度有着重要的影响。根据具有大面积、主动反射面的毫米波天线对面板的成形要求,提出了一种基于高精度模具、蒙皮开缝、真空负压和胶粘背筋的成形方法。建立了该成形过程的有限元模型,并利用接触算法实现了该过程的数值仿真。研究发现蒙皮开缝后能有效降低蒙皮内的应力水平。面板回弹引起背筋的不均匀变形是面板成形误差产生的主因。分析了面板形面曲率、蒙皮开缝长度和背筋高度等面板结构参数对面板成形精度的影响规律,为合理设计该工艺过程和提高面板的成形质量提供了重要依据。 相似文献