Study On Circle Optical Grating Encoder Error And Spatial Error Of ACMM

ACMM(articulated coordinate measuring machine) belongs to multistage tandem polar coordinate measurement system, its measurement error will be progressively transferred and enlarged, which made its measurement accuracy is several or even dozen times lower than the orthogonal measuring instrument, which restricted its application in practical engineering.The angle combination of the six circle optical grating encoders and circle optical grating encoder error is different at different measurement postures of ACMM, so does the measurement error create by circle optical grating encoder error when measuring different measurement points in the space or a fixed point in different postures. If we can find a relatively small area of the measurement error namely optimal measurement area and place the measured piece in optimal measurement area to measure, obvious can we improve the measurement accuracy. However, there are so many error sources of ACMM so that it is difficult for us to separately analyze the measurement error generated by circle optical grating encoder error, the paper establishes virtual prototype of ACMM by application virtual prototyping technology and analyzes the relationship between circle optical grating encoder error and distribution of the measurement error which lays the foundation for the future research, main research contents of this paper are as follows:1. Acquiring the mathematical expressions of circle optical grating encoder error and giving out the image display;2. Establishing virtual prototype of ACMM by application virtual prototyping technology and the virtual prototype eliminates most of the error sources so that can we separately analyze the measurement error generated by circle optical grating encoder error;3. Proposing a method to collect lots of points in the space by collecting points in a plane, the method solves the large workload and high complexity of collecting a large number of uniformly points in the space;4. Establishing the platform based on matlab and vectorized programming idea for analysing the measurement error generated by circle optical grating encoder error to analyze the measurement error of a fixed point、a plane and the whole measurement space, finding out the optimal measurement area and analyzing how can we reduce the whole measurement error by changing initial installation angle of the circle optical grating encoders.