Abstract: In order to reduce the centrifugal force affecting the big arm and decrease outer axis attitude error, the unloading system of the precision centrifuge is designed. This system comprises one loading vehicle instrument, “birdcage”, four draw bars, the upper indexing table, the lower indexing table and eight force sensors. According to the messages from the eight force sensors, unloading balance block is moved to realize unloading balance and to keep the engagement force of indexing table as a constant. The vehicle instrument moved automatically along the direction of centrifugal force when the centrifuge speeded up. The centrifugal forces of the vehicle instrument and the “birdcage” are same, and they only affect the draw bars instead of the big arm. So auto-unloading of the big arm is realized. By using computer, the data processing, acquisition and controlling the mechanism of unloading balance system, and the high precision on-line auto-unloading is realized.

Key words: Indexing table engagement, Computer control, Force sensor, On-line auto-unloading, Precision centrifuge