Study On The Coupling Error Mechanism Of Dual-mass Silicon Micro-machined Gyroscope

Silicon micromachined gyroscopes are microelectromechanical systems inertial sensors that use the coriolis effect to sense the angular rate of rotation of objects.It is widely used in vehicle stabilization system,image stabilization system,robot and other military and civil fields because of its small size,light weight,low cost and low power consumption.With the improvement of the performance of silicon micro-machined gyroscope,its application range becomes wider and the environment becomes worse.The large machining error limits the improvement of the performance of the silicon micro-machined gyroscope.The thermal environment sensitivity limits the application range of high performance silicon micro-machined gyroscope.Therefore,the analysis of the influence of machining error and thermal environment on the performance of the silicon micro-machined gyroscope is beneficial to improving the performance of the silicon micro-machined gyroscope.In this paper,the influence of machining error and thermal environment on the performance of the self-designed silicon micro-machined gyroscope is analyzed.The main findings of the study are as follows:1)The system modeling of a dual-mass silicon micro-machined gyroscopeAccording to the characteristics of the vibration mode of the dual-mass silicon micro-machined gyroscope,the contribution of each beam in the vibration mode is analyzed,and the multi-mode frequency model of the dual-mass silicon micro-machined gyroscope is obtained.The finite element simulation software ANSYS is used to carry on the simulation verification.The result shows that the error of theory and simulation is 7%.Then,according to the structural characteristics of the dual-mass silicon micro-machined gyroscope,a multi-degree-of-freedom structural dynamic model is established,and the displacement sensitivity of the dual-mass silicon micro-machined gyroscope is obtained by using the modal decoupling and inverse matrix method.2)Influence mechanism of machining errorFirstly,the zone stiffness of the joint is introduced to improve the theoretical model of the effect of beam width error on the orthogonal coupling coefficient.For the support beam system without coupling stiffness,the stiffness of the joint area is the main reason that affects the orthogonal coupling coefficient.The stiffness of the joint zone is verified by simulation.Then the influence mechanism of the comb-tooth clearance error and the anchor displacement error on the orthogonal coupling coefficient is discussed.Finally,the sensitivity of inner-driven gyroscope to coupling force is established and compared with that of outer-driven gyroscope.The results show that the sensitivity of outer-driven gyroscope to coupling force is low.Finally,its reliability is verified by simulation and experiment.3)Influence of thermal environment on Silicon micro-machined gyroscopeBased on the classical beam theory,the package structure of the dual-mass silicon micro-machined gyroscope(DSMG)is analyzed by using Timoshenko’s layered analysis method.Based on the structure characteristics of the gyro,the temperature characteristics of the comb-tooth clearance are obtained by establishing the force balance equation.The simulation results are given to verify the proposed method.Finally,the temperature coefficient of the strain of the anchor layer is verified by using the intuitiveness of the relationship between the stress and the acceleration frequency of the resonant silicon micro-machine.According to the working principle of the close loop of the gyroscope,the temperature coefficient of the comb-tooth clearance is verified by experiment.