Research On The Driving Circuit Of Vibrating String Gyroscope Based On The Principle Of Negative Phase Feedback

Gyroscope is a sensing device used to measure the angular velocity of an object.It is widely used in many fields such as navy,army,air force,and civil.Most traditional micromechanical gyroscopes based on the Coriolis effect use the amplitude detection method,which is difficult to balance the miniaturization and high precision of the gyroscope.The vibrating string gyroscope uses frequency detection.The thinner the vibrating string and the higher the frequency,the smaller the gyroscope,the higher the accuracy,the vibration frequency signal of the vibrating wire will modulate the acceleration signal and the vibration signal in the driving direction,so generating a stable and reliable driving signal is vital to demodulating the acceleration signal.Aiming at the shortcomings of the traditional self-excited driving method and the phase-locked loop driving method,a vibrating wire gyroscope driving circuit based on phase negative feedback was studied to meet the requirements of automatic adjustment of driving signals and fast and stable requirements.First,the basic theory and working principle of vibrating-string gyroscope are introduced,the dynamic model of vibrating-string gyroscope in the driving direction is studied,the equivalent GLC electrical model of the gyroscope is established,and the amplitude-frequency characteristics of the driving mode of the gyroscope are analyzed and verified.And phase frequency characteristics,its amplitude frequency characteristics explain the necessity of gyro resonance drive,and its phase frequency characteristics provide a theoretical basis for the design of gyro phase negative feedback drive circuit.Secondly,a frequency tracking loop based on phase negative feedback and an amplitude control loop based on automatic gain control(AGC)are designed.A simulink model of a complete closed-loop drive system was established,and the frequency tracking performance of the system when the natural frequency of the gyro drive frame changed drastically,as well as the drive performance in a high-frequency environment,were verified to verify the feasibility of the drive scheme.Then,a frequency tracking loop composed of a phase shift circuit,a sine-to-pulse circuit,an XOR phase detector circuit,a PI control circuit,a voltage-controlled oscillation circuit,and a square-wave to sine circuit are designed,and the peak detection circuit and PI control circuit and variable gain amplifier circuit(VGA)constitute the amplitude control loop,and the closed-loop driving simulation of the GLC circuit model equivalent to the gyro driving mode are performed.The results show that the closed-loop driving circuit can well implement the gyro natural frequency tracking and Control requirements for stableamplitude.Finally,a physical circuit board for the Ⅳ conversion preamplifier circuit,power amplifier circuit,and closed-loop drive main circuit required for the gyro drive test are designed and manufactured.The functions of each module are tested,and closed-loop drive tests are performed on the vibrating-string gyro The frequency tracking and amplitude stability performance of the closed-loop drive circuit are verified.