Quadric Surface Fitting And Error Analysis In Industrial Measurement

In industrial manufacturing,we often come into contact with the measurement and inspection of products with regular geometric shapes.The manufacturing accuracy of these products is to a certain extent a measure of a country's industrial manufacturing strength.A large part of these products are standard cylindrical and rotating paraboloid,such as rocket body and communication radar antenna.At present,there are many methods for fitting spatial cylindrical surface and rotating parabolic surface;unfortunately,there is no special research and Discussion on the local cylindrical surface and rotating parabolic point cloud data which are often encountered in industrial testing.In this paper,according to the fitting problem of point cloud data of local cylindrical surface and rotating paraboloid,which are often encountered in industrial measurement,combined with the geometric characteristics of cylindrical surface and rotating paraboloid,the fitting algorithm is studied.The main contents are as follows:1 This paper describes the principle of cylindrical surface fitting and several representative methods of spatial cylindrical surface fitting,and puts forward a parameter initial value search algorithm for local cylindrical point cloud fitting.By searching for more accurate initial parameters,the local cylindrical point cloud data can be fitted with the same accuracy as the current software SA.2 This paper describes a variety of rotating paraboloid fitting algorithms,and proposes a variety of initial value search algorithms for local rotating paraboloid point cloud data fitting.Experiments show that the prediction of fitting local rotating parabolic point clouds can be achieved.3 The three parts of industrial measurement and manufacturing,quadric surface fitting and error theory analysis are organically integrated together.Based on the knowledge of probability theory,a method of accuracy comparison between instruments with the same accuracy is proposed,and the accuracy of least squares estimator in surface iteration process is theoretically estimated by the indefinite multiplier method.