Comb Tuning Fork Wire Vibration Silicon Micro-machined Gyroscopes

The traditional mechanical gyroscopes and optical gyroscopes are broadly applied to the initial navigation field currently. Though they are characterized by high precision and maturity in manufacturing and application, they are flawed by their bulk volumes and heaviness, which limit their usage in micro-scale application and are contradict to current microminiature development trends. Micromachined gyroscope is characterized by miniaturization, integration, good dynamic performance, low energy consumption, easy to be digitalized, high reliability, long lifecycle as well as other advantages, whose characters surpass the limitation for traditional mechanical gyroscopes and optical gyroscopes to be used in micro-scale application, which holds valuable contribution to the those commercial and military industries which holds large demands of initial navigation technology.The precision of micromachined gyroscopes are calibrated by bias drift and resolution, respectively. Though they possess various advantages compared to their bulk counterparts, most micromachined gyroscopes developed by domestic and foreign research agents have low bias drift and resolution performance which merely reaches rate level application and limited to precise applications as initial level ones. Thus, it is the primary objective to improve bias drift and resolution performance of micromachined gyroscopes for micromachined gyroscopes research agents. This thesis is focused on a comb-driven-tuning-fork-two-lane-vibrating-silicon micromachined gyroscope structure aimed to improve bias draft and resolution performance based on the works of forerunner, especially base on the efforts of Georgia Institute of Technology of America.The symmetry dual folds spring suspension employed in this structure decoupled the mechanical coupling effects between the drive mode and the sense mode; the special isolation mechanism designed within the structure could largely decrease the cross talk to the sense signal by drive signal. The quadrate error of micromachined gyroscope can be lowered through decoupling and isolation design, which brings in improvement of bias drift performance. Through optimal design of the geometric parameter of the spring suspension, this structure is characterized by high quality factor, by which the foundation for the resolution improvement of was laid.Base on ANSYS finite element simulation software, this thesis verified the superiority of the design solution of this micromachined gyroscope. Through the decoupling analysis, the decoupling effect between drive mode and sense mode of the system decreased to below1.9% by employing folded beam design; through the isolation analysis, by the special layout design of drive combs and the folded beam, the orthogonal errors in the detection direction induced from the bias force of the driving force is lower to 2.5% of the one with no decoupling mechanism. Through theoretical analysis and Matlab simulation, it demonstrates that this micromachined gyroscope reached a quality factor of 51×105, which would bring in rather precise resolution.This micromachined gyroscope is characterized by predominant performance and novel structure design and its design was submitted to national patent agency for patent application.