Three laser beams monitoring method for linear movement error of datum cylindricity measuring instrument

The analyses of the effect of influence factors on cylindricity measuring instruments(CMI) measurement accuracy indicates that the reference guidance movement error is the technical bottleneck which hinder the further improvement of CMI accuracy In order to reduce the effect of the error on CMI measurement accuracy an interaction model has been established for the five kinds of guidance movement errors in space by following the general theory of guidance movement error. And furthermore, a three laser beams monitoring method based on the model above is proposed to monitor CMI linear movement error, which uses three detectors placed optimally on a movement guidance to monitor the translation displacement of a movement guidance with respect to the datum beam in x and y directions, uses the six translation displacements monitored by the three detectors to obtain the movement error of the movement guidance through modeling and calculation. The method proposed uses coordinate transformation to obtain the amount of guidance movement error in sensor's measuring direction, and eliminates the movement error from the measurement results, so it can be used to monitor and compensate the action errors of CNR linear movement guidance. It is therefore concluded that the method proposed is an effective technological approach to monitoring and compensating linear movement error in ultra-precision CMI.