REDUCING ERRORS OF A ROTARY DEVICE, IN PARTICULAR FOR THE DETERMINATION OF COORDINATES OF A WORKPIECE OR THE MACHINING OF A WORKPIECE

摘要

A method and apparatus for reducing errors of a rotary device of a coordinate measuring machine or a machine tool. The rotary device comprises first and second parts rotatable relative to one another about an axis of rotation of the rotary device, and a rotational position measuring device for measuring rotational positions of the first part and the second part relative to one another. Errors of the rotary device due to deviations between actual positions and axial alignments relative to ideal positions and an ideal axial alignment are measured over a range of rotary angles. Expected variations in the position of the first part or second part resulting from a deviation of the rotational movement of the rotary device from an ideal rotational movement are established from the error measurements. Rotational position measurement locations of the rotational position measuring device are established in accordance with the expected variations.

主权项

1. A method for reducing errors of a rotary device, which comprises a first part and a second part which is rotatable relative to the first part about an axis of rotation of the rotary device, and a rotational position measuring device for measuring rotational positions of the first part and the second part relative to one another, wherein the rotational position measuring device comprises a rotational position sensor and a measurement body interacting with the rotational position sensor for measuring the rotational position, wherein the rotational position sensor is connected to one of the first part and the second part and the measurement body is connected to the other of the first part and the second part, and wherein the method comprises the following steps:
determining error measurement values for measured errors of the rotary device due to deviations between, firstly, actual positions and actual alignments of the axis of rotation and, secondly, corresponding ideal positions and an ideal alignment of an ideal axis of rotation of the rotary device over a range of rotary angles corresponding to a plurality of different rotational positions of the first part and the second part relative to one another, establishing expected variations in a radial position of the first part or of the second part of the rotary device and/or expected variations in a position of the first part or of the second part relative to a direction tangential to the rotational direction of the rotary device which variations are expected as a result of a deviation of the rotational movement of the rotary device from an ideal rotational movement about the ideal axis of rotation, from the error measurement values for a plurality of rotational position measurement locations of the rotational position sensor at which rotational position measurement locations the rotational position sensor can measure the rotational position of the rotary device, and establishing at least one rotational position measurement location of the rotational position sensor in accordance with the expected variations, for which expected variations relative to the direction tangential to the rotational direction of the rotary device
are smaller than for other possible rotational position measurement locations and/orsatisfy a predetermined condition.