Research On Deadband Suppression Of Fiber Optic Gyroscope Based On Random Over-modulation

Inertial technology is the core technology of all kinds of motion carrier inertial navigation,guidance control,positioning orientation and attitude stability,and it contains a good autonomy,comprehensive information,real-time continuous,strong anti-interference carrier movement information perception technology.As new inertial sensitive devices,fiber optic gyroscope plays a vital role in the defense and civilian areas.In the project,the gyroscope produces the dead effect that lead to the output of gyroscope appears serious non-liner,and that indirectly affect the inertial navigation systems,so the appropriate method must be used to suppress the dead band of fiber optic gyroscope.Based on this,the mechanism of the dead zone of FOG is analyzed,and the appropriate method is chosen on account of the dead zone generation mechanism.Accordingly,a dead-zone suppression of the fiber optic gyroscope called random over-modulation is presented in a manner.Its main work is as follows:(1)The basic working principle is analyzed.Firstly,the structural components of fiber optic gyroscope are introduced and all-digital closed-loop insistence scheme of FOG is mainly elaborated,at the same time,analysis of the square-wave modulation and four-state modulation are introduced accordingly,At last,we introduced the generation of the step wave,the second closed-loop control in detail.(2)The dead-zone mechanism of fiber optic gyroscope is analyzed.It is shown that the dead-band generation mechanism of fiber-optic gyroscope has three aspects:the dead-band error caused by electronic cross talk,the nonlinearity of feedback loop device and the reset of step wave.Based on the dead-zone mechanism,several of schemes are compared and analyzed,which provides a theoretical basis to explore inhibition method of the dead band.(3)The dead-band test of fiber-optic gyroscope is introduced.Based on the national military standard test,the errors of the national standard test are analyzed at the same time,and the error is compensated accordingly,At last,we have to complete the test task to provide a theoretical support for subsequent improvements.(4)The experiment of random over-modulation of FOG is analyzed.This part is the core of the whole design.It mainly completes the design task of pseudo-random module design,modulation and demodulation module design and the function simulation to the whole module;At last,we complete the new threshold test again to compare the different effect of the suppression of dead-band.By testing,it is obvious that the threshold is reduced from the original0.0056~o/h to0.0043~o/h,closed about 23%.It is proved that the random over-modulation has a good effect on the dead zone of fiber optic gyroscope.