The calibration of circular scales and precision polygons

Cook, Andrew

doi:10.1088/0508-3443/5/10/308

Cited by 10 publications

(12 citation statements)

References 6 publications

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“…Some descriptions of the angular calibration are presented [8][9][10][11]. The calibration can be performed using the Moore's 1440 Precision Index as angle standard and angle polygon prism of 12 sides with the autocollimator.…”

Section: The Methods Of Circular Scale Calibrationmentioning

confidence: 99%

Research of the Angular Positioning Accuracy of the Experimental Test Bench

Giniotis

Bručas

2012

Geodesy and Cartography

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Most geodetic instruments are based on measurement of angular values. Such instruments as digital theodolites, total stations etc are used in geodesy, building structure, surveying, in machine engineering etc. Preliminary research of the accuracy of the test rig created for precise angular measurements is presented here. Visual angular scale accuracy measurements are given and some statistical parameters of measuring data are evaluated. Conclusions for further development of the test rig are formulated.

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Section: The Methods Of Circular Scale Calibrationmentioning

confidence: 99%

Research of the Angular Positioning Accuracy of the Experimental Test Bench

Giniotis

Bručas

2012

Geodesy and Cartography

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“…In Troughton's work, the artifact is a roller which is roughly matched to roll an integral number of times around the circle to be calibrated, but which is never exact and which he then proceeds to show how circle closure can be used to correct it to make a much better full-circle scale. Much more recently, Cook [5] describes calibrating an optical polygon by exactly solving a set of equations for angular differences between its faces.…”

Section: Brief Historymentioning

confidence: 99%

A simple method for high-precision calibration of long-range errors in an angle encoder using an electronic nulling autocollimator

et al. 2015

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We describe a simple method for high-precision rotary angle encoder calibration for longrange angular errors. By using a redesigned electronic nulling autocollimator, an opticalpolygon artifact is calibrated simultaneously with determining the encoder error function over a rotation of 2π rad. The technique is applied to the NIST vacuum double crystal spectrometer, which depends on precise measurement of diffraction angles to determine absolute x-ray wavelengths. By oversampling, the method returned the encoder error function with an expanded uncertainty (k = 2) of 0.004 s of plane angle. Knowledge of the error function permits the instrument to make individual encoder readings with an accuracy of 0.06 s (k = 2), which is limited primarily by the least count and noise of the encoder electronics. While the error function lay within the nominal specifications, it differed from the intrinsic factory curve, indicating the need for in situ calibration in high-precision applications.

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“…The methods of circular scales calibration were created and developed by such famous scientists as H. Bruns, G. Schreiber, A. Perard, H. Wielde, Heiwelynk, S. Yeliseyev, etc. [1,2,[4][5][6]. The "diameters" errors are determined by using those methods at angle intervals applying the control angles equal, for example, to 10°, 20°, 30°.…”

Section: Measurement Of Circular Scalesmentioning

confidence: 99%

Investigations Into the Accuracy of Angle Calibration

Giniotis

Rybokas

Petroškevičius

2012

Geodesy and Cartography

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Technical possibilities to create equipment for the calibration of flat angles are discussed in the article. The angular standard measure, the radian, has not been realised as a standard unit until now. Nevertheless, the unit of angular measure in degrees is used as the geometric measure of length in geodesy, machine engineering and other branches of industry – by multiangular prisms – polygons with an autocollimator, rotary tables, circular scales, etc. It should be noted that these angle measures are calibrated against the upper level measures (etalons) only at the several intervals depending on the number of sides (angles) of the polygon or the other standard measure. The methods of calibration of constant angle value in full circle are used as well. At the same time geodetic instruments, rotary tables of metal cutting tools and instruments, rotary encoders have a great number of discrete values. These values between the calibrated points remain unknown during calibration. The information received during calibration relative to all the information available can be evaluated using information entropy. The equipment of calibration permitting to select significantly more information would be essential for better accuracy assurance of instruments used in machine engineering, geodesy, building structures. Theoretical and technical background for justifying and developing such equipment for angular accuracy calibration is presented here. A modern scientific and technical background validates this concept.

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The calibration of circular scales and precision polygons

Cited by 10 publications

References 6 publications

Research of the Angular Positioning Accuracy of the Experimental Test Bench

Research of the Angular Positioning Accuracy of the Experimental Test Bench

A simple method for high-precision calibration of long-range errors in an angle encoder using an electronic nulling autocollimator

Investigations Into the Accuracy of Angle Calibration

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