Study On Structural Optimization Design Of Novel MEMS Tuning Fork Gyroscope

Benefiting from the small size,low power consumption,low cost,and mass production,MEMS gyroscopes have been widely used in military fields and civil fields.With the urgent need for high-performance MEMS gyroscope due to the rapid development of China’s aerospace,weapon precision guidance and other businesses,it is of great significance to strengthen independent innovation capabilities and develop high-performance MEMS gyroscopes.This paper presents a new decoupling structure around the MEMS tuning fork gyroscope.Studying from the basis of work theory,structure optimization,size optimization,input and output response,etc.,not only is the microstructure of the gyroscope optimized,but also its mechanical sensitivity is improved,and the vibration performance of the gyroscope is also analyzed,which provide guidance for the practical application of the gyroscope.Firstly,the paper details the working theoretical basis of the MEMS tuning fork gyroscope,including the physical basis—Coriolis effect and material properties—the elastic properties,dielectric properties and piezoelectric properties of quartz,explaining the working principle of the gyroscope structure.Secondly,the paper proposes a new decoupling structure of MEMS tuning fork gyroscope.Soon after,the gyroscope’s basic structural characteristics and advantages are analyzed.The mechanical model of the gyroscope structure is constructed.The expression of the mechanical sensitivity is deduced.The theoretical method of improving the gyroscope’s sensitivity is pointed out.Moreover,researching from the aspects of reducing the working frequency and improving the transmission efficiency of sensing motion combined with the specific structure of the gyroscope,the specific measures for the optimization of the gyroscope structure are explored—the square groove design of the base and the arc groove design between the tines,which guide the structure optimal design of the gyroscope.Then,the paper studies the influence of multiple characteristic size parameters such as the height of the tines,the distance between the tines,the height of the base and the width of the balance beam of the MEMS tuning fork gyroscope on its related vibration performance utilizing the Taguchi method.The feature sizes of the gyroscope are optimized based on the influence of multi-design variables and the demand of multi-performance indexes,which increases the transmission efficiency of the gyroscope sensing motion by about 18%,and reduces the working mode frequency by about 2.7k H_Z.Finally,the paper analyzes the input and output responses of the optimized gyroscope structure.The effect of electrode layout on driving vibration is studied for input response,which guides the optimal design of electrode layout.For the output response,the effect of the system quality factor Q value on the mechanical sensitivity of the gyroscope is studied,which guides the practical application of the gyroscope.The analysis shows that as the Q value increases,the improvement rate of the gyroscope’s mechanical sensitivity becomes slower and slower.The mechanical sensitivity of the gyroscope reaches 20.735nm/(rad/s)when the Q value is 40000.