In order to realize mass and center of gravity measurement of large-sized rotating parts, a set of combined measurement system for center of gravity measurement was developed to adjust the distance according to the length and supporting position of the parts to adapt to different lengths of the measured parts. The study focused on the center of gravity synthesis, error factors and error separation within the system. Firstly, two sets of center of gravity measuring equipment based on multi-point weighing method were used to conduct a joint test on the large-sized measured parts, and the center of gravity measuring model was analyzed. Secondly, the measurement error and its influence on the measurement result are were analyzed when the two sets of measuring equipment were not parallel. Finally, error signals were separated using the multi-step method, Fourier transform and inverse Fourier transform. Simulation experiments show that the residual center of gravity error of Y axis and Z axis is less than 0.3 mm when the tilt angle between two sets of equipment is below 0.3 degrees. The test results demonstrate that the center of gravity measurement error along the X axis is less than 2 mm, which indicates the measurement accuracy better than 0.02% as the length of the test object is about 10 000 mm, and the center of gravity measurement error along the Y axis and Z axis is less than 0.5 mm, which also indicates the measurement accuracy better than 0.02%. These findings indicate that the system enables high-precision measurement of the center of gravity for large-sized rotary products.
