Research On The Control Algorithm Of Two Points Of Constant Distance And Error Analysis

CO2 laser cutting controls a laser point’s position and a cooling point’s position to finish processing at the same time.The feature of the two controlled points is that they move along the same trajectory,and the distance between them stays constant in a single processing.The existing control strategy can not meet these demands.The feature of machine tool is using two linear axes and one axis to finish process.This topic has built a workpiece rotation processing mode mathematical model and a two points of constant distance rotation mathematical model to finish the design of an algorithm of controlling two points of constant distance due to machine tool’s feature.Calculation process has been proposed.Detailed calculation process of frequent machining trajectory such as straight line,circle,straight line and arc tangent has been researched in this paper.Reducing workpiece contour error needs to study rotation center positioning error and position error of two control-points’ affection on the two control-points’ position,this topic has build mathematical models for each error source’s affection on one control-point,derived formulas of each error source’s affection on control-point’s machining trajectory and use the formulas to build computer modeling and calculate trajectory of error.Tests have been done on real machine tool.Affection on the two control-points’ position has been summarized by comparing machining trajectory different of the two control-points.To test the correctness of error study,real contour error and theoretical error needs to be compared and real contour information should be measured.This topic uses scanning method to record workpiece’s information and edge detection to extracting workpiece contour.According to the error equation summarized in this paper,Using the iterative approximation approach way to calculate error number and direction.Using the result to adjust machine tool and the two kind of errors’ affection on processing progress.The control algorithm of two points of constant distance has been applied in a domestic NC system and relative application interface has been designed.Automatically parametric generating code function has been developed.It can generate processing code using input data.Tests of a real product have been done on real machine tool and the product’s size is correct with design size.The result has show the correctness of the algorithm and error analysis.