Research Of Measuring Technique For Planar Worktable Based On Laser Inferometer

The two-dimensional displacement stage is an essential part of manufacturing and inspection industry.Its motion accuracy determines manufacturing and detection capability.However,two-dimensional displacement station manufacturing technology is insufficient to meet the market demand.In actual use,the accuracy the two-dimensional displacement stage shall be improved by compensating for its motion error.In this paper,a two-dimensional displacement measuring system was designed based on 13 geometric motion errors in the ISO-230-1 standard.(1)The interferometer was considered as the measurement standard of displacement.A small part of the measurement light was used for angle measurement according to the principle of self-collimation.Thus,the angle and displacement were measured at the same time.The three-way time-sharing and split measurement was then designed using pentaprisms and reflectors.In this way,all the 13 geometric motion errors were measured.(2)Environmental parameter compensation and Abbe compensation for displacement were used to improve the accuracy of displacement measurement.(3)The drive control and data acquisition circuit box was set up using the MP451 USB card,MP422 E board and SH20403 stepper motor driver.The measurement value of the laser interferometer was considered as trigger signal of the acquisition system.All the data was collected under the continuous motion of the stage,which significantly improved measurement efficiency(4)In the Visual Studio environment,a two-dimensional precision stage automatic measurement program was written in C# language to achieve fast measurement.(5)Comparison tests were carried out for the measurement accuracy of the system under the ambient temperature of 20 ± 0.5 ℃,humidity of 50% to 60% and measuring range of 300 mm × 300 mm.The results showed that the measurement accuracy was better than 0.7μm and angle measurement accuracy was better than 0.4seconds.In addition,actual measurement was carried out for the existing two-dimensional stage.