Parameter curve cutter path oriented numerical control system contour error control method

Abstract

The invention provides a parameter curve cutter path oriented numerical control system contour error control method which comprises the following steps of: 1) calculation of the contour error; 2) calculation and control of the contour error compensation quantity, and is characterized in that: in the step 1), in each sampling period for performing curve interpolation on the parameter curve cutter path, the contour error epsilon is calculated according to the current actual cutter location point and the interpolation point on the tracked parameter curve cutter path, namely the shortest distancefrom the current actual cutter location point to the tracked parameter curve cutter path is calculated; in the step 2), the components of the contour error epsilon along the X axis, Y axis and Z axisare calculated, and the contour error compensation quantities are obtained by proportional control and superposed with the location control quantities for the following error on the X axis, Y axis and Z axis respectively; and then the result is output to a servo execution mechanism to perform contour error compensation control. The method provided by the invention has the advantages that: the contour error calculation precision is high, the contour error compensation method is simple and effective, and the contour precision can be obviously improved.

Description

technical field [0001] The invention relates to an error compensation control method, in particular to a contour error control method of a numerical control system oriented to a parameter curve tool trajectory. Background technique [0002] In the machinery manufacturing industry, the contours of many complex parts can be described by parametric curves (such as spline curves, Bezier curves, B-spline curves, NURBS curves, etc.), and correspondingly, parameter curves can be used to describe the tool paths for processing these parts . For the parameter curve tool path, the advanced CNC system mostly adopts the curve interpolation method. Compared with using a straight line segment to approach the parameter curve tool path and then performing linear interpolation, when using the curve interpolation method, all interpolation points are on the parameter curve tool path, and theoretically, the machining accuracy and processing speed can be improved at the same time. On the other ...

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Problems solved by technology

The problem with this method is that the Newton iterative method has high requirements for the initial value and a large amount of calculation, and sometimes it is difficult to meet the real-time requirements of the numerical control system.

Myung-Hoon LEE also proposed in this paper that in addition to the following error PID position controller of each axis, for the contour error obtained by approximate calculation, another set of PID controller is designed to calculate the contour error compensation, but the control parameters of the PID controller are very small. Difficult to tune

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