Micro circular path measurement of two-axis stage using a machine vision system and the application

摘要

Usually, verifying the 2D positioning accuracy of a multi-axes stage is not easy. This is because there is little such a device to measure the 2D path directly in micron accuracy. This paper studies on a measuring method for a micro circular 2D path precisely. A machine vision technique is used to trace the moving path of two-axis stage. This method is compared with the ball-bar system, which is commonly using in CNC machine tool companies for inspecting the performance of circular motion movement. However, it is not common to measure a small circular moving path as less than 0.1 mm diameter. The machine vision system is used to trace a target on the two-axis stage moving. To improve the target imaging quality and resolution, a zoom lens is used in this test. The accuracy of this method depends on the CCD resolution and the lens optics. This technique will be useful to trace a small object in the 2D micropath in real time accurately. Also, this method can be one of those that measure the positioning error vector in the working volume of CNC machine tool.