| Resonant optical gyroscopes have great potential advantages in miniaturized unmanned platforms,such as unmanned aerial vehicles,due to their combination of MEMS miniaturization and high-precision optical characteristics.They have received widespread attention and research from major research institutes at home and abroad.However,the signal generated by the Sagnac effect in the resonant optical gyroscope is very weak,and the equivalent radius change at 1°/h speed generated by a 10cm diameter resonant cavity is only10-14cm.Therefore,the stable input of the light signal and the calculation process of the weak signal are crucial in the resonant optical gyroscope system.In this thesis,the light source driving and signal processing circuits for resonant optical gyroscopes were designed and fabricated,respectively.The main research contents are as follows:（1）A"constant current+temperature control"driving control circuit was designed with the goal of designing a high stability narrow linewidth light source driving circuit and using a microcontroller as the core control.By using a reference voltage source and a tuning voltage to jointly act on the constant current driving module,the tunable function of the light source is achieved.The injection current and butterfly packaged diode temperature are controlled by the ADN8834 temperature control module to stabilize the output optical power and center wavelength of the light source,completing the circuit design of the resonant optical gyroscope light source driving.The light source driving circuit is tested in the temperature range of20～40℃.The current stability of the light source driving circuit is about 0.001%,the optical power output is about 12.27m W,the stability of the optical power reaches 0.16%,and the stability of the central wavelength is 0.23 ppm.（2）The goal is to design a high-precision gyroscope signal processing circuit,using FPGA as the core unit to design and implement the gyroscope signal processing circuit.The signal processing hardware circuit includes modules such as 2-way high-speed 16 bit A/D conversion,FPGA logic processing unit,EEPROM storage chip,serial communication,3-way D/A conversion,and low ripple power supply.The signal processing hardware circuit has been tested and the power output noise is less than 1m V,VAC＿RMS less than 500μV。（3）According to the detection requirements of optical gyroscope signal modulation and demodulation and frequency locking,analyze the hardware module parameters and timing control of the signal processing circuit,and complete the software module design of the signal generator,phase-locked amplifier,PID feedback loop,etc.At the same time,complete the serial communication work to achieve real-time modification of relevant parameters inside the FPGA by the PC,ensuring the stability of the gyroscope system during testing.After testing,the signal feedback module of the signal processing circuit can achieve controllable modulation signal output with a frequency of 0-5MHz and an amplitude of 0-6V.The system can achieve phase modulation,demodulation,and frequency locking functions internally.The peak to peak value after loop locking is about 800μV。... |
