A Method Of Establishments Of Angular Coordinates For Clustered Revolving Rays Based On Precise Time Interval Measurement

In the field of high-end equipment manufacturing,seldom measuring methods can meet the command of large-size(especially inside dimension),high precision,on-machine,automatic methods.A practical,high precision,on-machine,automatic measuring method based on clustered revolving laser rays was proposed by our research group.After further research,the key to improve the precision and measurement capability of clustered revolving laser rays is to get angular coordinates for every displacement value,has been found.Requirements about system to get angle coordinates for clustered revolving laser rays are proposed in this article.Optical encoder is one of the most commonly used tools in getting angle coordinates.Optical encoder gets angle information by relative rotation of stator and rotator.It's almost impossible to provide relative rotation for stator and rotator of optical encoder in current system.Meanwhile,axiality error is inevitable when using optical encoder.Other traditional angle measurement methods are not suitable for clustered revolving laser rays due to their complicated system or other reason.WMPS and Time-Grating are methods getting angle information based on time interval measurement.WMPS needs interaction system.Time-Grating method need devices precisely divided.They are not suitable for clustered revolving laser rays.A new method of establishing angle coordinates for clustered revolving laser rays based on precise time interval measurement is proposed in this article.With no precisely divided tools and other cooperative tools,angle measurement is transformed into time interval measurement.Based on displacement value itself,getting precise angle coordinates for every rotating displacement value through time interval measurement.A machine probe with power supply and wireless data transfer system is fabricated based on this method.The machine probe can be easily installed on machine tool.Two work pieces is made to verify the practicability of this method.They are a work piece with two dihedrals and an equilateral polygon hole with 28 sides.With machine tool and the tool probe,rotating measurements of these two word piece is carried on.Comparing with the standard data getting from Hexagon coordinates measurement machine,the error of dihedrals measurement results is about 10?,relative measurement error is about 0.028%.Comparing with the standard data getting from video measuring machine,the error of angle in equilateral polygon hole with 28 sides is below 3?,in the meantime,the error of side length in equilateral polygon hole with 28 sides is below 50 ?m.The accuracy of the measurement results is able to verify this method.