Contour error estimation method based on H-shaped precision movement platform

Abstract

The invention belongs to the technical field of precise and efficient numerical control machining, and provides a contour error estimation method based on an H-shaped precision movement platform. By means of the method, for free curves with different curvature changes, the contour error estimation accuracy can be effectively improved, and then contour errors generated in contour tracking movementare reduced. The method comprises the following steps that 1, the curvature rho and the curvature radius r at any one reference point R1(t) on an expected machining contour of the H-shaped precision movement platform; 2, the angle alpha between the tangent line at the reference point R1(t) on the expected machining contour of the H-shaped precision movement platform and the X axis is calculated; 3, according to a geometrical relationship, the coordinates (Ox, Oy) of the center of the internally tangent circle is calculated; 4, the central angle beta and the arc length l corresponding to the central angle beta are calculated by using the triangle area; 5, through the arc length l, the movement time deltat from R2(t) to R1(t) is calculated; 6, by using the second-order Taylor series expansion equation, the coordinates (R2x, R2y) of the R2(t) are calculated; 7, by using the triangle area, the estimated contour error Ec of any one path is calculated.

Description

technical field [0001] The invention belongs to the technical field of precision and high-efficiency numerical control processing, and relates to a contour error estimation method based on an H-type precision motion platform. Background technique [0002] In modern CNC machine tools, the contour following motion of multi-axis servo system is an important application and is widely used in various types of machining. Therefore, how to reduce the error in the process of contour tracking movement is the key development technology, and the indicators mainly used for contour tracking accuracy today are tracking error and contour error, where tracking error is defined as the distance from the expected position point to the actual position point; and the contour The error is defined as the shortest distance from the actual position point to the entire expected trajectory, so the contour error is an important basis for judging that the machining contour deviates from the expected tra...

AI Technical Summary

Problems solved by technology

When the distance from the actual position point to the approximate contour error occurrence point is used as the estimated value, if the desired contour is a free curve, the approximate trajectory will deviate from the actual command trajectory, resulting in inaccurate approximate contour error occurrence points and increasing the estimation error

However, the iterative comparison method takes a long time to calculate. If you want to obtain a more accurate contour error, the number of iterations and the time used may exceed the load of the contour tracking system. less suitable for contour-following motion control with compensation

Images