Structure Design And Dynamic Response Analysis Of Micro Inertial Sensor Under High Overload Impact

In recent years,in order to adapt to the precision firings of land,sea and air target,the guided projectile with a lot of equipment becomes a widely used weapon in advantage of small size,low cost and feasibility of battlefield environment in addition to guided missiles and rockets.In modern warfare,the researches of the missile guidance systems emerge and go deeper.The strapdown inertial navigation system(STRapdown)composes of the micro-inertial measurement unit and GPS.It has attracted much attentions because of its low cost,small size,high accuracy and strong anti-interference ability.It can realize the control of ballistic parameters of projectile flight and achieve the precision firings of targets.The projectile firing process is generally within 10 ms.It is a process of high overload and strong impact.Compared with the advanced micro inertial sensors abroad,the micro inertial sensors developed in China have a low survival rate in the high overload environment,and the output signal of zero deflection and zero deflection will deteriorate,resulting in the decrease of the accuracy of guided shells.The ability to resist high overload of micro-inertial sensors has become one of the key technologies restricting the application of missile guidance system in China.Micro inertial sensor is mainly composed of MEMS gyroscope and accelerometer,this article in view of the MEMS gyroscope and accelerometer anti-high overload,adopt the method of combining theoretical analysis and numerical simulation,the further study of two kinds of micro inertial sensors dynamic response under the environment of high overload,two types of the micro inertial sensors anti-high overload structure design method.The natural frequency formulas of two kinds of micro-inertial sensor sensitive structures in key modes are derived,the sensitive structures of two kinds of micro-inertial sensors are designed quantitatively,and the corresponding simulation verification analysis is carried out.The main research contents of this paper are as follows:(1)The gyroscope and accelerometer under impact load were simplified into a single degree of freedom vibration system,the theoretical formula of dynamic response of the system was derived,and the influencing factors of displacement response of micro-inertial sensors under high overload environment were studied.The results show that the dynamic displacement response of MEMS gyroscope and accelerometer sensitive structure can be regarded as a quasi-static process under high overload impact,and the larger the natural frequency of the system,the smaller the displacement.(2)The design method of high overload resistance structure of MEMS gyroscope and accelerometer is summarized,and the sensitive structure of MEMS gyroscope and accelerometer is designed.The design of sensitive structure against high overload mainly includes the design of stop block,support structure,coupling beam,increasing the stiffness of comb tooth and optimizing the transition region to reduce stress concentration.(3)The vibration models of MEMS gyroscope and accelerometer sensitive structures are established.The natural frequency formulas of the sensitive structure of gyroscope are derived for driving modal,detecting modal and driving codirection modal.Similarly,the theoretical formula of the natural frequency of the accelerometer in the working modal and the z-axis codisturbance modal is derived.The structure design method of gyroscope and accelerometer is established,and the final sensitive structure of gyroscope and accelerometer is quantitatively designed.(4)The dynamic response and nonlinear contact static analysis of the MEMS gyroscope and accelerometer sensitive structure are carried out.The results show that the improved gyroscope and accelerometer can resist high overload to a certain extent and meet the design requirements.The sensitive structure of gyroscope and accelerometer designed in this paper has similar results in dynamic response of contact collision and nonlinear contact static calculation.Therefore,nonlinear contact static analysis can be used to replace dynamic response analysis for strength check in the follow-up high-overload design,which can save the simulation calculation time and further shorten the design cycle.