Research On Dynamic Error Sources Analysis And Modeling Of Coordinate Measuring Machines

Modern manufacturing technology has put forward more exacting demand of speed and accuracy on Coordinate Measuring Machines (CMMs). High speed has become a new trend in CMM technology. However, with the increase of speed, the dynamic accuracy will decrease since dynamic errors will have a great impact on the accuracy and act as a barrier to the measuring cycle time. In this paper, the impact of velocity parameters on dynamic performance of CMMs is studied. And process of touch-trigger probing is studied experimentally and different DCC(direct computer control)parameters, which influence the dynamic probe errors, are also tested. The main dynamic error sources of CMMs are identified and analyzed in detail whist the influence of velocity parameters and position factors are taken into account.As for the probing system, the composition of dynamic probing error is studied. A new concept of functional diameter of tip is put forward and impact of DCC parameters on functional diameter is modeled. As for the machine loop, the dynamic deformation is studied. The relationship between dynamic deformation of machine structure and displacement error at the position of probe is modeled which validates the place-related characteristics of machine deformation.Besides, a method for evaluating the positioning accuracy under different dynamic conditions using a laser interferometer on a moving bridge type CMM is designed and analyzed, which might be utilized for the purpose of dynamic calibration and dynamic error compensation of coordinate measuring machines.