第六章 角度及角位移的测量资料

6.1 Overvi源自文库w
Unit and standard transfer of angle
Natural standard of angle & circle closed principle
Material standard of angle & properties of indexing error
The indexing precision of grating circle is ±0.2″ and higher. The resolution is 10″or 20″. Usually used to high precision and highintelligence instrument and machine.
Units of angle
International system of units
Radian(rad)，The radian is the angle subtended by an arc of a circle that has the same length as the circle's radius. 弧的 长度与半径之比
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School of mechanical and power engineering/Henan polytechnic university
Chapter Six Angle & Angular Displacement Measurement
Contents 6.1 Overview 6.2 Measurement of a Single Angle 6.3 Measurement of Circular Indexing Error 6.4 Measurement of angular displacement
milliradian(mrad). A milliradian is 1/1000 of a radian.
Non-international system of units
Degree system：second of arc(")minute of arc(′)degree(°)
Conversion
Material reference & property of indexing error
Circular grating
Similar to linear grating principle
Line error has little influence on the result because of averaging effect
The angle indexing of circle is 5′, 10′ and 1°, and high resolution is got by subdivision.
Usually used in static measurement of angle and the circular indexing error.
标尺光栅 指示光栅
Material reference & property of indexing error
Polygonal Prism
High-accuracy angular standard appliance, used to check accurately dividing device installed already
Natural standard of angle & circle closed principle
The natural standard of angle: the circular angle of 360°. It is a standard with no error.
Circle closed principle A circumference is equally divided into several angles, and each division is not an ideal value and is of error. But, the sum of all angle indexing error on the whole circle is zero.
Up to ±0.5″～±1 ″ of indexing precision after verification Usually in concert with reading system of auto-collimation
1°= 60´, 1´= 60" 1rad = 180/π°≈ 57.296°
Standard transfer of angle
Similar with length, angle quantity is also transferred. That is, angle reference with low accuracy is checked using angle reference with high accuracy gradually.
0 grade(±3 " )； 1 grade(±10 " )； 2 grade(±30")；
Material reference & property of indexing error
High-accuracy dial
在圆盘的某一圆周上刻有一系列的等分刻线以实现 圆周等分的器件称为度盘。
The dial is a standard for many angle-measuring instruments and dial checking instruments.
Material reference & property of indexing error
Angular gauge block
I type(one operating angle) and II type(four operating angles)
A set is used usually consisting of several angular gauge blocks with different operating angle.