Calibration method of non-orthogonal nonlinear 3D scanning probe under cylindrical coordinate measuring machine

Abstract

The invention provides a non-orthogonal nonlinear three-dimensional scanning probe calibration method under a cylindrical coordinate measuring machine, which includes: using a standard sphere as a calibration reference, constructing multiple scanning trajectories, establishing an optimization problem with spherical constraints as the objective function, and For the coefficient of the third-order item is too small, the coefficient estimation is adjusted to obtain a spherical constraint objective function suitable for optimization, and the Levenberg-Marquardt algorithm is used to realize the optimization. The third-order nonlinear optimization model of non-orthogonal 3D scanning probe is established by multivariate Taylor function expansion theory, which is the extension of orthogonal 3D scanning probe, and the model has wide applicability. The optimization is carried out twice, the first optimization of low-order coefficients, based on which the third-order coefficients are estimated, the order of magnitude of the coefficients is adjusted to the same order of magnitude in the second optimization, and the objective function is fine-tuned synchronously, directly optimizing all third-order coefficients, avoiding the When the third-order optimization is performed directly, the third-order coefficient cannot be optimized due to the large difference in magnitude.

Description

technical field [0001] The invention belongs to the field of precision measurement, and in particular relates to a method for calibrating a non-orthogonal nonlinear three-dimensional scanning probe under a cylindrical coordinate measuring machine. Background technique [0002] Coordinate measuring machines can detect the size, shape and position of parts, and are widely used in industrial production. Its measurement accuracy is not only related to the precision of coordinate axis motion control, but more importantly, it is closely related to the accuracy of the probe used. With the development of sensor technology and measurement technology, the 3D scanning probe plays an increasingly important role in scanning measurement due to its high precision. Three-dimensional scanning probes can be divided into orthogonal probes and non-orthogonal probes. For orthogonal probes, the three-dimensional output is independent of each other, so the calibration of the probe parameters is r...

AI Technical Summary

Problems solved by technology

[0004] In order to overcome the shortcomings of many non-orthogonal 3D scanning probe calibration parameters and difficulty in optimization, the present invention proposes a non-orthogonal nonlinear 3D scanning probe calibration method under a cylindrical coordinate measuring machine, using a high-precision standard sphere as a calibration reference. Construct multiple scanning trajectories, establish an optimization problem with spherical constraints as the objective function, and adjust the coefficient estimation for the coefficient of the third-order item is too small, obtain a spherical constraint objective function suitable for optimization, and use the Levenberg-Marquardt algorithm to achieve optimization

Images