Research On Detection And Control System Of Micro Hemisphere Resonant Gyroscopes

MEMS gyroscopes have the advantages of small size,low power consumption,low cost,and integration.The gyroscopes can be well embedded in electronic control systems,improving the performance and decreasing the volume and cost of systems.Among the MEMS gyroscopes,the micro hemispherical resonator gyroscopes(?HRG)have received extensive attention because of their high symmetry,high Quality(Q)and good impact resistance.The ?HRGs are considered to be the key technologies to achieve the navigation level of MEMS gyroscopes.Therefore,it is of great significance to study the measurement and control technology to improve the performance of ?HRGs.In this paper,a digital system of dual-closeloop based on FPGA is designed,and the corresponding equivalent model,simulation and verified experiments are presented.Firstly,the operational modes and principle of ?HRGs are introduced.And the impacts of stiffiiess asymmetry and damping asymmetry are analyzed.Furthermore,the structure,dimension and fabrication process of the ?HRG are demonstrated,respectively.Secondly,the analytical method of the dual-closeloop based on envelope model is proposed.The time-domain parameters such as the settling time,overshoot amplitude,and overshoot time of the drive loop are calculated based on envelope model.At the same time,the loop stability and bandwidth of sense loop are analyzed.The experimental simulation is carried out to verify the correctness of the two loop designs.Finally,the hardware system is built and the related experiments are accomplished.The virtual Coriolis force method is adopted to test the frequency response of the ?HRG.The system bandwidth is extended to 3.4 Hz from 0.87 Hz.The scale factor of the system is 2.25mV/°/s at the input range of ±1500/s,and the scale factor nonlinearity is 0.081%.The bias stability and instability are 62.3°/h and 21.8°/h.The random angle walk is 3.1 0/?h.The experimental results indicate that the detection and control system proposed in this paper accomplishes the functional verification of the ?HRG successfully and achieves the desired goals,which provides strong technical support for the development of the ?HRG.