Development Of The Hybrid Opto-electrical Rotary Joint

Rotary joint, which is a necessary outfit for transmitting signals between two equipments rotating oppositely, can be used to transmit many signals and energy. With the appearance of the combination of electrical slip rings and fiber optical rotary joints, both original demands of high power transmitting and large information bandwidth for video signal delivery become possible and feasible. Therefore, the hybrid Opto-electrical rotary joints will become the prospective focus and widely used in the future.Based on the single channel fiber optical rotary joint combined with the electric slip ring, which has been developed in our laboratory, a hybrid opto-electrical rotary joint is designed. It can be used to transmit both high-speed optical signal and original electrical signal, so as to satisfy the requirement for special working condition.Firstly, according to the analysis of the origin and character of the signals transmitted through rotary joints, an optical transmission system is established in this dissertation. After the introduction of several parts of the system, mainly concerning the function, principle as well as the theoretical analysis and practical application of the system, the optoelectronic devices that fit for the combined rotary joints are chosen.Secondly, according to the structure of electrical slip ring, the structure of original single channel fiber optical rotary joint in our laboratory is improved and optimized, which can lessen the size of fiber optical rotary joint to assemble with electrical slip ring with rare influence of the function of rotary joint. Meanwhile, two kinds of structure of the optical transmission system are designed for different complex practical application, based on the analysis of the working condition.Furthermore, utilizing the characters of CAN bus and RS-485 bus, a bus circuit is designed for converting the electric bus signal into optical one and transmitting them through fiber optical rotary joint. At the meantime, some problems in signal transmission are resolved in the case of variable baud rate.Finally, the experiments are carried out to validate and testify the performance of hybrid rotary joint, and good agreements with the foregoing theoretical analysis are achieved.