Triangular phase modulation wave driving apparatus for closed loop feedback control of fiber-optic gyroscope

Abstract

The invention discloses a triangular phase modulation wave driving apparatus for closed loop feedback control of a fiber-optic gyroscope. The apparatus is used for achieving the closed loop feedback control of the fiber-optic gyroscope. In the technical scheme, on the basis of a conventional sawtooth wave phase modulation method, the apparatus is modified so as to solve a problem caused by flashback of voltage during restoration time of the sawtooth wave. The improved design is described as follows: by means of difference characteristics and symmetry of DAC and a driving circuit, two paths ofdifferential triangular wave, which are symmetrical about 0V, are generated by the DAC and the driving circuit; by controlling two paths of analogue switches, the signal channels of the two paths of triangular waves are switched with each other at the vertexes, so that the two paths of differential triangular waves are spliced to form two paths of differential sawtooth waves. The sawtooth wave, when being applied to two electrodes of Y waveguide, has equivalent effect as directly-outputted sawtooth wave in a conventional scheme. After bias modulation is overlapped, the closed loop feedback control of the fiber-optic gyroscope is achieved.

Description

technical field [0001] The invention relates to a fiber optic gyroscope closed-loop feedback control triangular phase modulation wave drive device, which belongs to the technical field of fiber optic gyroscopes. Background technique [0002] As an inertial angular velocity sensor based on the Sagnac effect, the fiber optic gyroscope is widely used in the field of inertial measurement due to its unique technical and performance advantages. [0003] The signal detection methods of fiber optic gyroscopes can be divided into open-loop detection methods and closed-loop detection methods. The open-loop fiber optic gyroscope obtains a stable π / 2 phase offset by increasing the square wave phase modulation, and realizes the maximum measurement sensitivity, but the scale factor stability and nonlinearity of the open-loop gyroscope are particularly poor. In order to achieve an accurate and stable linear scale factor, a feedback control loop is introduced on the basis of the open-loop ...

AI Technical Summary

Problems solved by technology

[0004] However, in actual use, there are some problems in sawtooth wave phase feedback modulation: (1) The voltage flashback phenomenon at the reset moment of sawtooth wave requires DAC (digital-to-analog converter) and its driving circuit (composed of operational amplifier and resistive capacitor device) ) has a large bandwidth and slew rate, and often due to the performance limitations of these devices in bandwidth, settling time and slew rate, the modulation waveform generated has a large distortion at the reset moment, and the settlement results of the fiber optic gyroscope (2) The voltage flashback of the sawtooth wave at the reset moment has rich spectral components, which will introduce more electromagnetic interference problems

However, this modulation method needs to introduce a very large phase amplitude, which puts high demands on the operating voltage range of the phase modulation drive circuit and phase modulator

In addition, dual-slope phase modulation is not suitable for digital closed-loop solutions, because the digital quantization effect makes the measurement of time difference have large errors, thereby reducing the detection accuracy of the gyroscope

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