Study On The Effect Of Air Pressure And Temperature On Q Value Of MEMS Multi-Ring Gyro

As an important application field of MEMS technology,because of its low cost,small size,high reliability and low power consumption,the MEMS gyroscope has been widely used in automobile,electronics,aerospace and other fields.It has been taken as one of the priority technologies which must be focused for many countries.As a new member of solid-state undulatory gyroscopes in the family of MEMS gyroscopes,the multi-ring gyroscope has become the most promising type of gyroscope with high performance due to its excellent resolution,high sensitivity and good temperature characteristics.Quality factor?Q value?is the key index to measure the dynamic characteristics of the multi-ring gyroscope in the working process,and energy dissipation is an important factor affecting its quality factor.Damping is the main form of energy dissipation,among which air damping,thermoelastic damping and anchor damping are the three main types.Because the structure design of single anchor of multi-ring gyroscope makes its anchor damping far less than the other two kinds of damping,so this paper only studies the air damping and thermoelastic damping.Air pressure and temperature are the key factors in the air damping and thermoelastic damping of multi-ring gyroscopes,respectively.Therefore,this paper studies the influence of air pressure and temperature on Q value of multi-ring gyroscopes.Firstly,the working principle of the multi-ring gyroscope is analyzed,the structure and mode of the gyroscope are studied,and the electromechanical interface parameters of the gyroscope are deduced,which lays a foundation for the design of the driving closed-loop circuit.Secondly,ring-down method is selected as Q value test method by comparison.Simulink module is used to realize the behavior level simulation of multi-ring gyroscope driving closed-loop circuit,and the design of multi-ring gyroscope driving closed-loop circuit based on the principle of automatic gain control is completed.This circuit can be used as Q value test circuit.Then,the experimental study on the effect of air pressure on Q value is completed.It is concluded that vacuum packaging technology is necessary to maintain high Q value of multi-ring gyroscope and the proportion of air damping below 0.04 Pa can be neglected.Finally,the theory of single-loop thermoelastic damping is studied,and the simulation of multi-loop Q_TEDED in full temperature range is realized by using finite element software COMSOL.The experimental study of temperature on Q value is completed,and the conclusion that thermoelastic damping occupies the largest proportion in the total damping of multi-loop gyroscope is drawn.