High precision real-time contour error estimation method

Abstract

The invention relates to a high precision real-time contour error estimation method, belongs to the precise high efficiency numerical control processing technology field and particularly relates to the high precision real-time contour error estimation method on the basis of an initial value regeneration Newton iterative method in a numerical control parameter curve interpolation processing process. The method comprises steps that firstly, before each step of iterative calculation, according to present interpolation point parameters and actual cutter location points, an iteration parameter initial value on a parameter curve for Newton iterative calculation perpendicular foot points is calculated on the basis of a first order Taylor series expansion method; secondly, a Newton iterative method is utilized, a single step iteration parameter final value is calculated according to the iteration initial value; thirdly, for avoiding greatly increasing the algorithm calculation time, iteration is ended through double constraints of an iteration termination condition and a largest iteration frequency condition, a perpendicular foot point parameter estimate is acquired, and a contour error vector estimate is further calculated. Through the method, iteration divergence can be effectively avoided, contour error estimation precision is improved, and the method has great signification for guaranteeing contour control precision during parameter curve interpolation processing.

Description

technical field [0001] The invention belongs to the technical field of precision and high-efficiency numerical control machining, and in particular relates to a high-precision real-time contour error estimation method based on an initial value regeneration Newton iteration method in the process of numerical control parameter curve interpolation. Background technique [0002] With the rapid development of major engineering fields such as aerospace, energy and power, the requirements for the machining accuracy of CNC machine tools for processing complex curved surface parts are constantly increasing. Due to the existence of factors such as servo hysteresis, nonlinear links, external disturbances, and dynamic characteristic mismatches in the CNC system, deviations between the actual machining trajectory and the ideal contour often occur, affecting machining accuracy. Therefore, it is the key to ensure the machining accuracy of CNC machine tools to consider the multi-axis coupli...

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Problems solved by technology

[0003] Document "A Novel Contour Error Estimation for Position Loop-Based Cross-Coupled Control", Yang et al., IEEE / ASME Transactions on Mechatronics, 2011, 16(4): 643-655, this document proposes a method based on close arc approximation Contouring error estimation method, however, this method is only applicable to two-dimensional plane contours, and the estimation accuracy is low when the following error is large; the literature "A Real-time contouring errorestimation for multi-axis motion systems using the second-orderapproximation" , Zhu et al., International Journal of Machine Tools and Manufacture, 2013, 68: 75-80, this document proposes a real-time estimation method for the second-order approximate space contour error based on the point-to-curve distance formula. When the value is large, the estimation accuracy is also low, and the estimation algorithm obtains the distance value from the actual point to the ideal curve, not the contour error vector value

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