Investigation On Precision Measuring Technologies For Profiles Of Complex Rotary Bodies

Three dimensional profile measuring machines for large rotary workpieces are urgently needed in precision engineering. In order to achieve high accuracy, several essential measuring components including precision length gage with accuracy of tens of nanometers and air bearing rotary table are applied.A precision system is built for measuring the profiles of the complex rotary bodies.Error separation is critical for improving the accuracy of the system. In order to obtain higher accuracy, the random and systematic errors are analyzed and separated. In the measuring system, roll and pitch caused by the probe tilt violate the Abbe principle. Roll is removed by using two probes and pitch is separated by the autocollimator method. The radial run-out and the perpendicularity error between the probe and the spindle axis are compensated by a two-probe-two-step method carried out on a standard hemisphere artifact. As the form error of the artifact is mixed with the perpendicularity error, the least squares method is applied to fit the hemisphere and work out the perpendicularity error and the form error of the hemisphere. Finally, numerical validation is presented using the Matlab program to demonstrate the effectiveness and correctness of the proposed method. The measurement for the calibrated hemisphere is carried out, and error separation techniques are also employed to achieve more precise and more complete results.Uncertainty evaluation is important for assessing the performances of the measuring systems. The multiple-try Metropolis (MTM) algorithm is applied for sampling and uncertainty propagation for error sources due to its advantage in dealing with large dimensional problems.Finally, a summary of the whole work is presented and further improvements in the future work are suggested.