Load Effect On Equivalent Circuit Of Piezoelectric Micromachined Modal Gyroscope And Simulation Optimization For AGC Circuit

In this paper,a new type of all solid-state angular velocity sensor was introduced which is called Piezoelectric Micromachined Modal Gyroscope(PMMG).Because of the particular cuboid mass made of special material and structure combining respective advantages of all solid-state gyroscope and micro MEMS gyroscope,the PMMG in this paper has the preponderance of high resistance against impact and vibration.With the rapid development of MEMS technology,people pay more attention to the inertial gyroscope which has a big progress on size and precision.Currently,the study on piezoelectric micro gyroscope focuses on miniaturization,besides,the sensor mechanical load effect research has been extensively developed.Generally,on behalf of the core component of the micro sensor,the output electrode of piezoelectric resonator is mostly connected with charge amplifier,however,the research on electrical load effect on piezoelectric resonator features is rarely reported.Adopted a method based on series resistance and admittance circle,the article solved the headache that the stimulus condition of PMMG is hardly meet by using traditional impedance analyzer.And on this basis,the paper focused on the equivalent circuit and its electrical load effect of PMMG which needs a special voltage incentives.Through mapping the admittance circle diagram of PMMG,the article analyzed and obtained its equivalent circuit parameters under near the resonance frequency.Then comparing the experiment results for PMMG equivalent circuit connecting with or not charge amplifier,the paper found that the circuit parameters of PMMG with charge amplifier has changed,especially for circuit resonance frequency which reduced from 346.119 kHz to 344.979 kHz.Finally,the conclusion was drawn that if the charge amplifier is applied to piezoelectric sensor load side,more attention should be paid to the sensor circuit features especially resonance frequency.Driving circuit is the necessary part to guarantee PMMG's normal work even in resonance condition.The driving mode for micro gyroscope in this article chose the AGC(Automatic Gain Control)system which requires stability for incentive vibration and voltage amplitude.In this paper,the performance of AGC circuit especially peak value detection circuit was improved based on Multisim13.0 software so that the stability of micro gyroscope driving system is optimized in the simulation level.