A dynamic angle metrology system based on fibre-optic gyroscope and rotary table

Dynamic angle measurement (DAM) plays an important role in precision machining, aerospace, military and artificial intelligence.Because of its advantages including high sensitivity, solid state and miniaturization, fibre-optic gyroscope (FOG) has great application prospects in the field of DAM.In this paper, we propose a dynamic angle metrology method based on FOG and a rotary table to evaluate the DAM accuracy with FOG.The system synchronously collects data from the FOG and rotary table, and analyses the DAM accuracy of the FOG for different sway conditions compared with that of the angle obtained from the rotary table.An angle encoder in the rotary table provides absolute or incremental angular displacement output with angular displacement measurement accuracy of 10 ′′ (0.0028 • ) and angular displacement repeat positioning accuracy of 3 ′′ (0.00083 • ), and can be used as an angle reference.The experimental results show that the DAM accuracy of the FOG is better than 0.0028 • obtained with the angular encoder, and the absolute DAM accuracy of the FOG is better than 0.0048 • for given conditions.At the same time, for the multi-path signal synchronization problem in the metrology field, this paper proposes a signal delay measurement method combining test and algorithm procedures, which can control a delay within 25 µs.