Research On The Structure Design And Calibration Technology Of Dual-axis Rotation Modulation MEMS-INS

Recently,based on the gradual improvement of precision of Inertial Measurement Unit(IMU)of the Micro Electro-Mechanical System(MEMS),MEMS-based micro inertial navigation technique is gaining high attention and booming promptly with its advantages of price,size,etc.Currently,the common MEMS-IMU has been with great measurement errors.Its precision relies on MEMS integration and package techniques.Additionally,the measurement precision can be developed effectively by the calibration technology with the assistance of high-precision rotation mechanism.Therefore,biaxial rotation mechanism is purposely designed for assignment of alignment,calibration,and rotary modulation,etc.,of inertial navigation system(INS)on the basis of corresponding lab projects;the measurement results of MEMS-based INS are calibrated and offset by analyzing each error term,constructing error models,and studying calibration techniques.Initially,the task of design for the biaxial rotation mechanism is completed,while the principle prototype is produced as well.According to requirements of projects,the overall design blueprint and layout of the biaxial rotation mechanism is provided,then each function is designed modularly.The model of standard components is chosen,and the construction of nonstandard components is devised.In addition,3D model is established for the biaxial rotation mechanism,and then it undergoes the analysis of mechanics and dynamics.Meanwhile,the components complete production,heat treatment,and surface treatment.In the end,the package and simulation of prototype is proceeded.Secondly,each error term of the biaxial rotation-modulation MEMS-based INS is analyzed.It studies the error characteristics of MEMS-IMU and the effect of each error on the system.Then,the specific manifestation of each error term is exhaustively derived for the biaxial rotation mechanism.The Gyro is also exemplified to derive the detailed expressions of gyro measurement error induced by the errors described above.It is indicated that random noise affect calibration of MEMS-IMU severely under the mooring state.Thus,Allan analysis method is adopted to quantitively study random error.In addition,it researches the discrete calibration method of MEMS-IMU,and the calibration of least squares ellipsoidal modulus constraint.Furthermore,the algorithm based on the biaxial rotation mechanism is validated by the experiments outside lab.Static multi-position calibration method is designed mainly for the bias error which cannot be solved through mentioned method.It proposes one calibration method for MEMS gyro based on the integral of angular velocity.Then,the test based on biaxial rotation indexing is underwent to verify its effectiveness.By the comparative experiment of high-precision three-axis turntable,it validates impact of rotation indexing mechanism error on calibration results of MEMS-IMU.At last,the system-level calibration method of MEMS-IMU is researched under the condition of mooring state.Considering the idea of system error equation and rotation modulation,30-dimention Kalman Filter is constructed.The frequency characteristics of measurement data is analyzed under mooring states for designing the IIR complementary lowpass filter to improve solution accuracy of velocity error.The observability of MEMS-IMU error parameters is studied.By semi-physical and full-simulation experiment,it validates the system-level calibration algorithm on the design of biaxial rotation mechanism.