Speed ​​Planning Method for Constant Speed ​​Curve Interpolation in Speed ​​Sensitive Interval

Abstract

The invention discloses a speed-sensitive section constant-speed curve interpolation speed planning method, belongs to the technical field of precision high efficiency numerical control machining, and especially relates to a speed-sensitive section constant-speed adaptive processing feeding speed planning method in a parameter curve interpolation process. The method comprises steps of: determining, at preset feeding speed, a parameter section on a curve which does not satisfy geometric accuracy and machine tool driving capability constraint so as to determine speed-sensitive sections; by using the machine tool driving capability as constraint, determining the feeding speed value of each speed-sensitive section by inverse scanning speed decrease process speed planning and forward scanning speed increase process speed planning; by using the machine tool driving capability as constraint, determining the curve parameters of speed increase initial point and end point and the curve parameters of speed decrease initial point and end point of a transition area between the speed-sensitive sections and inputting the curve parameters into a interpolator to achieve section constant-speed parameter curve interpolation satisfying geometric and driving constraint. The speed-sensitive section constant-speed curve interpolation speed planning method is convenient and reliable, and has practical value to precision high-efficiency numerical control 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 feed speed planning method for constant-speed adaptive machining in a speed-sensitive interval in a parameter curve interpolation process. Background technique [0002] At present, the rapid development of high-end equipment manufacturing has posed severe challenges to digital control processing technology. For traditional linear and circular interpolation CNC machining, there are many defects when processing complex curves and curved surfaces, for example, the approximation error generated when using tiny straight lines and arc segments instead of curves, and the processing code file consumes a large amount of storage , frequent acceleration and deceleration caused by first-order discontinuities at the corners, etc. Therefore, parametric curve interpolation techniques have been extensively studied in recent years. ...

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Problems solved by technology

[0003] Consult the prior art documents and find that the document "Real-time NURBS command generators for CNCservo controllers", M.-Y.Cheng etc., International Journal of Machine Tools and Manufacture, 2002, 42 (7): 801-813, this document adopts a constant The machining feed rate is used for parameter curve interpolation. However, if the feed rate is too high, it will easily lead to bow height error at the position with large curvature of the curve, and the acceleration and jerk of the feed axis will be too large; if the feed rate is too low, it will affect Machining efficiency at positions with less curvature of the curve

The document "A real-time configurable NURBS interpolator with bounded acceleration, jerk and corder error", Annoni et al., Computer-Aided Design, 2012, 44(6): 509-521, this document proposes a method based on acceleration, jerk and bow height error Constrained non-uniform rational B-spline curve interpolation speed planning method, however, the feed speed planned by this method changes in real time during the interpolation process, that is, the speed fluctuates greatly, which is not conducive to the improvement of the machining surface quality. In addition, the method Real-time calculation of the feed speed value at each interpolation point requires forward-looking and interpolation preprocessing, which consumes a large amount of storage and calculation. Once the calculation amount exceeds the performance limit of the controller, it is easy to cause vibration or even damage to the machine tool

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