Optimization Design And Simulation Of Double Drive And Double Sense Micro-gyroscope

MEMS micro-gyroscope is a sensor that uses Coriolis force to detect the angular velocity.It is widely used in military,automotive,aerospace,and medical devices due to their advantages of low cost,small size,and low power consumption.With the continuous expansion of its application fields,it has gradually developed into a hot spot of global research.However,the performance of silicon micro-gyroscopes is currently at the rate level,how to improve performance has become the focus and difficulty of silicon micro-gyroscope research.At present,the research on the optimization design of micro-gyroscope performance is still quite lacking,and most of them on the single-degree-of-freedom micro-gyroscope.There are few studies on the performance optimization design of multi-degree-of-freedom micro-gyroscope.Therefore,improving and developing the existing optimization design method to form an optimization design method suitable for multi-degree-of-freedom micro-gyroscope will play a key role in the design and manufacture level of MEMS micro-gyroscope,and has important practical application value.In order to take into account both sensitivity and bandwidth of gyroscope and optimize its dynamic performance,the multi-objective optimization design method is proposed based on response surface method and genetic algorithm.The introduction of the response surface method can solve the difficulty that the objective functions of the sensitivity and bandwidth of the micro-gyroscope cannot be constructed.The optimization of the multi-objective genetic algorithm can optimize the sensitivity and bandwidth simultaneously.Design variables and constraints are determined based on feature extraction.The second order response surface approximate models of the sensitivity and bandwidth are built by the response surface method and the least square method,and multi-objective genetic algorithm is applied to optimize the models.The proposed optimization design method is used to optimize two different types of double drive and double sense micro-gyroscopes respectively,which effectively improve the sensitivity and bandwidth of the gyroscopes.A series of optimization schemes are obtained which can select different optimization schemes according to actual needs,and obtain micro-gyroscopes with different performance.The optimization results reflect the effectiveness of the optimization method,which can provide reference for the optimization design of multi-degree-of-freedom micro-gyroscope.The equivalent electrical model of the first type of micro-gyroscope is established according to the principle of equivalence between the dynamic equation and the electrical equation by using PSpice.The modeling method of electrical model is introduced into the modeling of four-degree-of-freedom gyroscope.The dynamic performance of optimized gyroscope is simulated and analyzed,which avoids the interference of structural processing error and circuit coupling error on the dynamic performance of the gyroscope.The error between the simulation result and the theoretical result is less than 1%,which verifies the correctness of the optimization result and reflects the feasibility of the optimization method.This method can provide guidance for the experimental study of the dynamic performance of the four-degree-of-freedom gyroscope.According to the sensitivity and bandwidth obtained after optimization,the structure and structural parameters of the second type of double drive and double sense micro-gyroscope are designed.A new method for calculating the stiffness coefficient of U-beams is proposed.In the light of the designed structural parameters,the finite element model is built by using the finite element analysis software ANSYS and the modal analysis is carried out.The simulation results of the vibration modes and natural frequency are consistent with the theoretical results.The mode order of the micro-gyroscope is determined which ensures that the designed modes and natural frequency of gyroscope are not affected by the interference modes.In order to investigate the stability of the performance of the optimized gyroscope,it is necessary to consider the influence of the drive stiffness nonlinearity on the bandwidth and sensitivity.Therefore,the first type of double drive and double sense micro-gyroscope is selected to discuss the effect of the drive stiffness nonlinearity on the performance of gyroscope of different optimization schemes?different degrees of bandwidth broadening?.It is found that when the drive stiffness nonlinear coefficient is greater than 10¹¹N/m³,nonlinear characteristics such as frequency offset,amplitude jump and multi-stable solution tend to occur.But whether the nonlinear characteristic affects the output of the gyroscope depends on whether there is a multi-stable solution region in the bandwidth.When the increase of the bandwidth is less than 17.91%,the performance of the gyroscope is not affected by the drive stiffness nonlinearity.When the bandwidth increases above 17.91%,the drive stiffness nonlinearity will affect the gyroscope and reduce the stability of the detection signal.The results can provide theoretical guidance for improving the performance stability of micro-machined gyroscopes.