20-04-2010, 03:30 PM
Abstract
The accuracy of the precise machines (e.g. Coordinate measuring machines) is of micrometer range and even less. The play of the bearings, the change of the position of moving parts, wear, environment influence, etc. reduce the final accuracy. The existing methods to increase the accuracy of precise equipment are complicated and of high cost. The authors present a new concept in the design of error compensating systems - active frames and structures for precision technological equipment and measuring machines. It is proposed to insert into the structure active elements (e.g. piezoceramic or TERFENOL-D plates or components) and control their displacements with electric or magnetic fields, thus compensating the various errors. Piezomechanic correction systems are used for raster scale error correction, in photoelectric or other types of transducers and for final correction of 3-D machine elements position. Active error compensation covers not only measurement systems, but also opens new ways of increasing the accuracy of such typical components of technological machines as beddings, slideways, fixing and datum keeping surfaces. New structure units of precise correction mechanisms - active kinematic pairs, are presented. Equations for calculation of correctional displacement are derived. Examples and possible areas of application are shown.