Investigations into the accuracy of angle calibration

Abstract

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.

Kampų kalibravimo tikslumo tyrimas

Santrauka. Straipsnyje nagrinejamos technines galimybes sukurti plokščioj o kampo kalibravimo irengini tiksliems kampu matams kalibruoti. Plokščiojo kampo vienetas radianas iki šiol nera laikomas kampo mato etalonu. Kampo matas laipsniais gali būti nesunkiai sukuriamas ir atkartojamas geodezijoje taikant geometrinius ilgio matus, o mašinu gamybos ir kt. pramones šakose – naudojant daugiakampes prizmes (poligonus) su autokolimatoriais, pasukamuosius optinius stalus, apskritimines skales ir pan. Reikia pažymeti, kad plokščiuju kampu matai kalibruojami tik retais intervalais, tiek, kiek turi briaunu daugiakampe prizme arba kitas pirminis matas, taikomas kaip etalonas. Taip pat šiam tikslui yra taikomi pastovaus kampo kalibravimo visame apskritime metodai. Geodeziniams prietaisams, stakliu pasukamiesiems stalams ir keitikliams būdinga didelis rodmenu diskretumas. Ju tarpine verte bei paklaidos lieka nenustatytos, taip pat išlieka daug nežinomos informacijos vertinant informacines entropijos metodu. Didesnio diskretumo ir reikiamo tikslumo plokščiojo kampo kalibravimo irenginys padetu užtikrinti didesni gaminiu, statybiniu darbu bei geodeziniu matavimu tiksluma ir informatyvuma. Čia pateikiamas teorinis ir techninis plokščiojo kampo kalibravimo irenginio tikslingumo pagrindimas ir, remiantis turimu techniniu bei moksliniu potencialu, aptariamos jo sukūrimo galimybes.

Raktažodžiai: kalibravimas, apskritiminė skalė, etalonas, kampas, tikslumas.

First published online: 03 Aug 2012

Keyword : calibration, circular scale, etalon, angle, accuracy