Correction Method of Repeated Positioning Error of 3D Worktable

Abstract

The invention provides a correction method for a three-dimensional worktable repositioning error. The correction method includes the steps: mounting an image acquisition system in a z-axis direction, keeping the position of a three-dimensional worktable in the z-axis direction fixed, and keeping the mounting position and the shooting angle of the image acquisition system unchanged; horizontally moving the three-dimensional worktable on an XY plane to a P1 point under control of a control host; acquiring an image P1 of the P1 point by the image acquisition system; transmitting a command of moving to the P1 point on the XY plane again by the control host when repositioning operations are needed; acquiring an image P2 of a repositioned actual arrival point by the image acquisition system; computing pixel position offset (delta a and delta b) of the image P1 and the image P2 by a rapid image matching method, and transforming the pixel position offset into position offset (delta x and delta y) according to the sizes of the images; acquiring position compensation instructions according to the position offset, and performing position compensation to correct the repositioning error. The correction method has the advantages of low cost and high repositioning error correction accuracy.

Description

technical field [0001] The invention belongs to the technical field of repeated positioning error correction, and in particular relates to a correction method for repeated positioning errors of a three-dimensional workbench. Background technique [0002] At present, the position control system of the three-dimensional workbench is mainly: the control host is connected with the actuator through the driving parts, and the actuator is directly linked with the controlled three-dimensional workbench; at the same time, the position detection device is directly installed on the three-dimensional workbench as the actual position. Detection and feedback device; its working process is: the control host issues an instruction to position the three-dimensional workbench to the theoretical position coordinates, so that the actuator is driven by the driving parts to move the three-dimensional workbench; then, the three-dimensional workbench is detected by the position detection device The ...

AI Technical Summary

Problems solved by technology

[0005] This method can correct errors caused by factors such as drive motor out of step. However, using a grating encoder as a position detection device, on the one hand, the cost of the grating encoder is relatively high; There will also be a problem of decreased accuracy in detecting the position offset of the detector, thereby reducing the repeat positioning accuracy of the entire 3D workbench position control system

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