Design For Control Circuit Of Mechanically Dithered Ring Laser Gyro And Research On Gyro Signal Processing

As an ideal part of inertia navigation, the mechanically dithered ring laser gyroscope (MDRLG)has been moving towards maturity overseas, in comparison, its development in our country is not assuccessful yet; as a result, deeper investigation on control circuit of MDRLG is necessary for us tograsp key technology as well as to improve its characteristics such as precision, reliability, ability ofanti-atrocious environments and so on. Based on a type of MDRLG, the control circuit and digitalsignal processing method of MDRLG were researched and designed.In the aspect of frequency stabilization control circuit: Based on the analysis of scale factormodified model of MDRLG, demands to precision of frequency stabilization were deduced;Characteristics of control circuit were analyzed, and through analyzing the influence of outsideinterference on frequency stabilization, causes of “mode hopping” were found. Path length controlmethods based on laser gain curve were investigated, and then a digital DC frequency stabilizationcontrol method was introduced.In the aspect of dither control circuit: Firstly, Fundamental theory of dither bias was introduced;Secondly, Basic principles of dither noise injection were investigated, and a noise injection systemwas designed to eliminate dynamic locks. Thirdly, Math model of dither mechanism was establishedand it was proved through harmonics analysis that square wave and its1st harmonic wave areequivalent for driving effects. Finally, a digital dither control scheme was designed which implementsfunctions of dither control and noise injection successfully.In the aspect of Digital signal processing: based on modeling and research on the RLG signaloutput channel, a design method of digital filter was put forward which takes both the noise filteringeffect and the frequency characteristic into account.The experimental results prove that the new control circuit implements functions of dithercontrol and noise injection successfully, and it also solves the problem of “mode hopping” efficiently,it also proved that the gyro works normally. The method of digital filter design takes both theefficiency of noise filtering and frequency characteristic into account, which has good applicationvalue in engineering.