Structural Design And Error Analysis Of(100)Crystal Nested Ring Silicon MEMS Gyroscope

The nested ring silicon micro-electromechanical gyro has the advantages of high mechanical sensitivity,small mechanical thermal noise,good precision performance,etc.It is the research direction of high performance micro-gyro with the most development potential in recent years.At present,nested ring silicon micro-gyros are usually fabricated using(111)wafer silicon wafers,using two symmetric vibration modes of n=2 as the driving and detecting modes.However,the nested ring gyro with the n=2mode as the working mode is more sensitive to the crystal orientation error during processing.In order to avoid excessive gyro frequency cracking due to the error,the nested ring gyro design of the working mode is designed.The chip size is 10mm*10mm,which is not suitable for further design requirements.In this paper,we study a nested ring gyro that uses(100)silicon wafer fabrication and uses two symmetric modes of n=3 as the driving and detecting modes.In addition to improving the above-mentioned crystal orientation error sensitivity,the material used also has outstanding advantages such as in-plane out-of-plane decoupling and good MOS process compatibility.The main research contents include the following aspects:1、According to the structural characteristics and working principle of the nested ring gyro,the basic theoretical model of the nested ring silicon micro-gyro is established,which provides the parameter index for the structural optimization design of the gyro.And then,the adaptability of the nested ring silicon micro-gyro substrate material and its working mode is analyzed.The reason why the(100)crystal n=3 mode nested ring gyro is developed in detail.Finally,the working principle of the nested ring gyro as the distribution Quality under different working modes is analyzed.2、The design of the(100)crystal nesting ring gyro structure is designed.The structure optimization of the mass block suspension optimization scheme is proposed.Finally,the machining process of the gyro is designed.After processing and testing comparison,the optimized mass suspension method successfully achieved the effective improvement of the gyro Quality factor.3、The processing error of the gyro after machining is analyzed.The identification scheme of the stiffness axis angle error and the electrode angle error based on electrostatic repair is proposed and tested.4、A miniaturized(100)crystal face nested ring gyro prototype was developed and its performance was tested.The final zero-bias stability of the prototype is 4.16459°/h,the scale factor nonlinearity is 23.2ppm,and the overall performance is superior,which verifies the correctness of the design direction of the gyro prototype.