Spline curve interpolation algorithm for high quality processing

Abstract

The invention discloses a spline curve interpolation algorithm for high quality processing, and the spline curve interpolation algorithm for high quality processing comprises the following steps: quickly pre-interpolating the numerical control machining curve, recording the length of the interpolation path and the maximum / minimum value of the acceleration / deceleration process; calculating the maximum acceleration and most much acceleration of the acceleration / deceleration process, having subsection on the acceleration / deceleration process, calculating quadratic polynomial speed equations of each section; obtaining the speed equation according to the pre-interpolating stage at the real time interpolating stage, adopting the strategy that the theory chord length is close to the practical chord length for building the construction function, estimating the initial value of the interpolation parameter and building the parabolic interpolation polynomial, using the Newton iteration method for exactly calculating the interpolation parameter. The speed plan adopts five-section S curve acceleration / deceleration control algorithm for guaranteeing continuous change of the speed and accelerated speed, the bounded change of the accelerated acceleration speed and the running stability of the machine tool; the calculation of the interpolation parameter adopts the combination of parabolic interpolation method and Newton iteration method for controlling the feeding speed fluctuation of the real time interpolation in the ideal level and satisfying the high quality processing requirement.

Description

technical field [0001] The invention relates to speed planning and interpolation parameter calculation of spline interpolation in high-quality machining, and belongs to the technical field of numerical control machining. Background technique [0002] For the processing of complex surfaces and curves, the traditional numerical control system uses discretized tiny straight line segments or arc segments to approach the curves. This method is easy to cause the discontinuity and fluctuation of the feed speed profile, destroying the smoothness of the workpiece surface, and the large number of programs generated increases the communication burden between CAD / CAM and the computer numerical control system CNC, which affects the real-time interpolation sex. Spline curve is the CAD / CAM data exchange standard stipulated by the International Organization for Standardization. It is widely used in CAD systems, but its development in CNC systems is relatively lagging behind. Only some high...

AI Technical Summary

Problems solved by technology

The uniform parameter interpolation algorithm treats the interpolation parameter increment as a constant for real-time interpolation. Although the control is simple, it is easy to cause vibration of the machine tool because it cannot control the feed speed.

Taylor expansion method and Newton iteration method realize constant feed speed interpolation, improve calculation accuracy, and reduce speed fluctuations, but do not consider the speed change requirements during acceleration and deceleration, it is difficult to guarantee interpolation accuracy, and there are errors that are difficult to control question

The adaptive speed interpolation algorithm automatically adjusts the feed speed according to the requirements of machining accuracy, so that the string height error is controlled within the allowable range of accuracy, but it does not consider the actual acceleration and deceleration capabilities of the machine tool, and excessive acceleration and jerk during machining It will cause a great impact on the machine tool, thus affecting the processing quality

The acceleration control interpolation algorithm, which takes the acceleration constraint into consideration, reduces the vibration of the CNC machine tool during the machining process, but this method is complicated to implement.

Images