New type optical fiber positioning unit device for LAMOST

This paper proposes an optical fiber positioning unit device for LAMOST(Large Area Multi-Object Fiber Spectroscope Telescope), It consists of a central shaft revolving mechanism, and eccentric shaft revolving mechanism relative to central shaft. The central shaft turns round at the range of -180degrees to +180degrees and the eccentric shaft turns round at the range of -90degrees to +90degrees driving by each control motor. When positioning, the optical fiber end moves on the focal plate throughout, and can never deviate from focal plane. It has simple structure, could be machined and assembled and taken down easily and could be ensured machining practices easily, so could be reduced manufacture costs. The unit sets mechanical electrical zero position detecting device to reduce the accumulate error of multi-positioning. Testing result have demonstrated this new double revolving optical fiber positioning unit device can accord with the demand of LAMOST entirely.