NURBS curve high-speed prospective interpolation method

Abstract

The invention relates to velocity planning technologies for numerical control systems, in particular to an NURBS curve high-speed prospective interpolation method. The method comprises the steps that on the basis of the curve self-adaptive interpolation technology, S-type velocity planning is adopted, and the kinematics formulas of the jerk, the acceleration, the feedrate and the interpolation distance of a self-adaptive deceleration area in the interpolation process are obtained; a data structure of data stored in a prospective window in the interpolation process is obtained; the prospective window is established, and the minimum value of the prospective window is obtained; the length of the backtracking distance in the prospective process is determined, and expressions of the acceleration and the jerk in the backtracking process are established; a curve is interpolated, and the data in the prospective window are adjusted dynamically after interpolation every time until interpolation is completed. By the adoption of the method, fluctuation of the acceleration and the jerk can be effectively controlled, the processing quality is ensured, the length of the backtracking distance can be accurately determined, the interpolation time is shortened, and the interpolation efficiency is improved.

Description

technical field [0001] The invention relates to a speed planning technology of a numerical control system, specifically a high-speed forward-looking interpolation method for NURBS curves. Background technique [0002] NURBS curve interpolation technology is the key technology of PC-based open CNC platform. In the NURBS curve interpolation process, in order to ensure the processing quality, it is necessary to limit the bow height error within the specified range through adaptive interpolation, but the acceleration and deceleration requirements in the adaptive interpolation process may exceed the maximum capacity of the machine tool, resulting in The jerk not only affects the processing quality of the machine tool, but also vibrates the tool and affects the tool life. Therefore, it is very important to effectively control the jerk in the processing process to improve the processing quality. [0003] Most of the existing interpolation algorithms control the jerk through forwa...

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Problems solved by technology

[0003] Most of the existing interpolation algorithms control the jerk through forward-looking interpolation, but in the existing forward-looking algorithms, when the acceleration or jerk in the adaptive deceleration zone exceeds the limit, it needs to interpolate again, and The average speed of the re-interpolation process is reduced, so the re-interpolation process approximates the arc length of the parameter curve more accurately, causing the backtracking distance determined in the algorithm to be longer than the actual backtracking distance, therefore, the re-interpolation process may be slow in the last part A low-speed operation area appears, resulting in an increase in interpolation time and a decrease in interpolation efficiency

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