Spline curve interpolation parameter calculation method

Abstract

The invention belongs to the precision and efficient numerical control machining technical field and relates to a spline curve interpolation parameter calculation method, in particular, an interpolation point curve parameter calculation method capable of decreasing speed fluctuation in a spline curve interpolation process. The method includes the following steps that: instruction parameter values of interpolation cycles are written into a function relative to time, and a two-order Runge-Kutta method is utilized to calculate the instruction parameter initial value of a next interpolation cycle; feed speed which is calculated based on the parameter initial value is compared with ideal feed speed, so that a parameter compensation value can be calculated; and the curve parameter value of a next interpolation point is determined according to the parameter initial value and the parameter compensation value, so that low-speed fluctuation spline curve real-time interpolation can be realized. With the method of the invention adopted, speed fluctuation in a curve interpolation process can be effectively suppressed under the premise that iterative calculation is not carried out. The method has a practical value in the improvement of spline curve interpolation machining quality.

Description

technical field [0001] The invention belongs to the technical field of precision and high-efficiency numerical control processing, and in particular relates to a method for calculating interpolation point curve parameters for reducing speed fluctuations in a spline curve interpolation process. Background technique [0002] Complex surface parts with complex surface structures are more and more widely used in aerospace, energy and power fields. With the rapid development of the high-end equipment field, the manufacturing industry has continuously improved the processing quality and processing efficiency requirements for such complex curved surface parts. In view of the fact that the machining tool paths of complex curved surface parts are mostly curves with complex geometric features, there are many defects when using traditional linear and circular interpolation CNC machining, such as the approximation error generated when using tiny straight lines and circular arc segments ...

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Problems solved by technology

[0003] The document "Parametric interpolator versus linear interpolator for precision CNCmachining", Yang et al., Computer-Aided Design, 1994, 26(3): 225-234, this document proposes a second-order Taylor technique expansion parameter calculation method, however, this method requires Calculate the second-order derivative of the curve, and there is a large rounding error; the literature "A real-time predictor-corrector interpolator for CNC machining", Tsai et al., Journal of Manufacturing Science and Engineering, 2003, 125(3): 449-460 , this document proposes a closed-loop curve interpolation parameter calculation method based on parameter estimation-correction. However, when calculating the curve parameters in this method, an iterative cycle is required, and the parameter value cannot be output until the accuracy condition is met, and the calculation time cannot be predicted. Not conducive to real-time imputation

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