System and method for numerical control (NC) workbench error self correction based on machine vision

Abstract

The invention provides a system for numerical control (NC) workbench error self correction based on machine vision. The system comprises an X-Y-Z-coordinate motion workbench, an image collecting system is arranged on a motion body of the X-Y-Z-coordinate motion workbench, a calibration plate is arranged on an objective table of the X-Y-Z-coordinate motion workbench, and an industrial computer is connected with the image collecting system. The invention further provides a method for NC workbench error self correction based on the machine vision. The method comprises the following steps: controlling the motion body and a high-resolution industrial camera to move, and collecting sequential images; obtaining a current absolute coordinate according to the imaging data of the motion body at different positions, comparing with a movement directive the encoder feedback value of a servo motor, and obtaining positioning error compensation values; and continuously conducting positioning detecting at different positions, and enabling the positioning error compensation values of all positions to be stored into a databank. According to the system and the method for NC workbench error self correction based on the machine vision, the defects of the prior art are overcome, self calibration and compensation can be conducted to the X-Y positioning error of the whole workbench, and positioning accuracy is markedly improved.

Description

technical field [0001] The invention relates to a machine vision-based self-correction system and method for X-Y plane positioning errors of a numerical control workbench, belonging to the technical field of three-coordinate motion workbenches. Background technique [0002] Three-coordinate motion workbenches are generally used as automation devices in modern manufacturing, and the positioning accuracy of its X-Y plane motion determines the performance of the device and the accuracy of processing and testing. The traditional method to ensure positioning accuracy is to use a rotary encoder as a positioning feedback device, but it cannot compensate errors due to uneven lead screw lead and backlash. The use of linear grating feedback can make up for this loss of accuracy to a certain extent, but due to the expansion or contraction of the workbench or grating affected by temperature, or the perpendicularity of the X-axis and Y-axis during installation, positioning errors will be...

AI Technical Summary

Problems solved by technology

The traditional method to ensure positioning accuracy is to use a rotary encoder as a positioning feedback device, but it cannot compensate errors due to uneven lead screw lead and backlash.

The use of linear grating feedback can make up for this loss of accuracy to a certain extent, but due to the expansion or contraction of the workbench or grating affected by temperature, or the perpendicularity of the X-axis and Y-axis during installation, positioning errors will be introduced into the system. Cannot be effectively compensated by grating or encoder

[0003] The traditional method of correcting the above errors is to use a laser interferometer for correction. The correction work is very cumbersome, and due to system handling or other reasons, repeated corrections are required, and the accuracy is difficult to guarantee.

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