Akima spline fitting based look-ahead interpolation method

Abstract

The invention provides an Akima spline fitting based look-ahead interpolation method. The method is characterized in that the Akima spline fitting is that the parameters corresponding to each interpolation point are calculated by the centripetal parameterization method, and then the data points are fitted into a smooth Akima spline by the Akima five-point interpolation method; the look-ahead interpolation is that different values are returned for real-time interpolation by the look-ahead interpolation calculation according to the processing precision requirement, the programming speed of a numerical control system and the maximum speed information; the real-time interpolation is that the real-time feeding speed is adjusted according to the look-ahead interpolation returning value, then a structural equation is created according to the known Akima spline equation and interpolation cycle and other information, then the primary iteration value of the next interpolation method is predicated, and finally the interpolation parameters are accurately calculated by the newton iteration method. According to the method, the data points to be processed are fitted through the Akima spline, so that the actuating efficiency is increased, the smoothness is high, the fitting precision is improved while the interpolation real-time performance is ensured, the accuracy and flexibility are improved, and the actual state of a workpiece can be restored to the maximum.

Description

technical field [0001] The invention belongs to the technical field of numerical control processing, and in particular relates to a forward-looking interpolation method based on Akima spline curve fitting. Background technique [0002] At present, the production and manufacture of components with complex curved surfaces is of particular importance in industries such as aerospace, automobiles, ships, cutting tools and molds. For the processing of complex curved surfaces and curves, the traditional CNC system uses discrete small straight line segments or arc segments to approach the processing curves. This method is likely to cause discontinuity and fluctuations in the feed speed profile, destroying the smoothness of the workpiece surface, and causing A large number of programs increase the communication burden between CAD / CAM and computer numerical control system CNC, which affects the real-time performance of interpolation. Although spline curves are widely used in CAD syst...

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Problems solved by technology

However, the fitting process and mathematical calculation of NURBS curves are relatively complicated, and it is difficult to meet the real-time performance of interpolation.

Another method is to fit the processing path specified by the continuous tiny line segment into a Bézier curve, and improve the processing quality of the workpiece surface by interpolating the Bézier spline curve, but this method needs to calculate additional Bézier curve control points. also more complicated

Another method is to use the Cubic spline curve to fit the tool trajectory for interpolation, but the Cubic spline curve itself has a tendency to swing, and changing one data point may affect many parts

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