Mindaugas Rybokas

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 rece...

ANALYSIS OF MEASUREMENT SYSTEM AS THE MECHATRONICS SYSTEM

The paper deals with the mechatronic arrangement for angle measuring system application. The objects to be measured are the circular raster scales, rotary encoders and coded scales. The task of the measuring system is to determine the bias of angle measuring standard as the circular scale and to use the results for the error correction and accuracy improvement of metal cutting machines, coordinate measuring machines, robots, etc. The technical solutions are given with the application of active materials for smart piezoactuators implemented into the several positions of angular measuring equipment. Mechatronic measuring system is analysed as complex integrated system and some of its elements can be used as separate units. All these functional elements are described and commented in the paper with the diagrams and graphs of errors and examples of microdisplacement devices using the mechatronic elements.

Assumptions of Centering – Leveling Device Application in Mechatronic Angle Measuring System

This paper deals with the presentation of the new centering – leveling device developed in Vilnius Gediminas Technical University. Precision angle measuring systems are always combined of many mechanisms and devices which influence angle measurement accuracy. Therefore, every one of them has to be investigated separately. This device can be used as a separate device to perform a slight movement of measured object or it can be used as a part of mechatronic angle measuring system. This paper presents preliminary results of centering – leveling device minimum pitch determination and analysis of further development of this device as a part of mechatronic angle measuring system.

POLYNOMIAL ERROR APPROXIMATION OF A PRECISION ANGLE MEASURING SYSTEM

Abstract The paper deals with the calibration of a flat angle measuring system. The article describes a comparative method for using a multi-angular prism (polygon) with autocollimator along with an angle measuring system. The components of angle measuring system is analysed in the paper. The article also presents polynomial error approximation and the obtained results of calibrating the precision angle measuring system as well as discusses preliminary assumptions for further research.

Analysis of angle measurements and a new approach to vertical angle calibation

Abstract Testing and calibrating geodetic instruments is an important metrological procedure for precise instrumentation used in industry and geodesy. Electronic geodetic measuring instruments consist, among other elements, of circular scales and angular encoders for angle determination in two perpendicular horizontal and vertical planes. The accuracy of the instrument mostly depends on the accuracy of angle standards used for angle calibration in the horizontal plane. Although many methods are developed for angle calibration, the majority of those are not available for calibrating angles in the vertical plane. The method described in the International Standards of vertical angle calibration validates field testing geodetic instruments by taking precise angle readings between the calibrated points placed at long distance and height. Difficulties in creating such calibration basis and inconveniencies in proceeding with this field at long distances may appear. Also, the traceability of length and angle meas...

PECULIARITIES OF PRODUCING AND MEASURING CIRCULAR SCALES

Abstract The paper deals with investigation into manufacturing circular scales and its accuracy evaluation methods and means considering the new development of production and measurement methods based on advancing laser instruments. The article describes the results of recently conducted analysis and presents initial trials of applying them in practice.