Research On Interface Circuits And Integrated Technology Of MEMS Disk Resonant Gyroscope

The MEMS disk resonant gyroscope(DRG)has become the one of the focuses of high-performance micro-gyro researches with the advantages of both micro mechanical gyro and solid-wave gyro.It has an urgent demand in the fields of aerospace and tactical weapons.At present,the researhes on interface circuit and integration technology of MEMS DRG need to be improved,which has become the main factor that inhibts the improvement of its system performance and integration development.There are following problems in the researches of MEMS DRG interface circuit.Firstly,the eletromechanical coupling effects(EMCE)between drive and sense modes of DRG significantly affects the stability of drving loop.There are rare in-depth studies of EMCE neither on the theorethical nor the anti-coupling circuit design.Secondly,the commonly used mode-matched circuit is realized by open-loop,which cannot adjust the matching voltage adaptively with the change of environment.Thirdly,the temperature compensation of DRG adopts the traditional method which needs planty of measurement and adjustment work and has difficulties in batch production.The batch measurement and ASIC integration technology are particularly important for the practical application of DRG.In view of the above problems,this paper conducts in-depth research on the electromechanical coupling characteristic,design method of mode-matched circuit,and temperature characteristic and carry out the research on the interface circuit of DRG and the integration technology of ASIC.First,the eletromechanical coupling effect of DRG is studied throretically.The model of DRG driving-mode contains EMCE is established by analyzing the mechanism of EMCE.The effect of EMCE on driving-mode is obtained by the model simulation.The design of highly-integrated anti-coupling driving circuit is guided by the model law,and the function of anti-coupling self-excitation drive on interface circuit chip is realized.Experimental results show that the circuit effectively eliminates EMCE,thus verifying the correctness of the model.Second,the active mode-matching method of DRG ASIC is studied.Based on the analysis of the mode-mismatch theory and the principle of static adjustment,the stepwise active mode-matching method is proposed on the basis of frequency division multiplexing.The on-chip tuning reference signal is introduced which combined with quadrate flag signal in sense-mode realizing the closed-loop control.The closed-loop axis adjustment circuit and closed-loop frequency modulation circuit are designed according to this method.The experimental results show that the circuit can realize the active mode-matching in the whole temperature range with mismatch <0.03 Hz,and the validity of the active mode-matching method is verified.In addition,the temperature characteristics and temperature compensation technology of DRG are studied.The temperature characteristics model of DRG is established based on the theoretical analysis of the mechanical structure.The complete rule of the temperature implication on gyro output is obtained by the simulation of the model.The characteristic curve of temperature can be obtained by the measurement of third characteristic points,which greatly reduces the amount of measurement and adjustment compared with the traditional method.In the experiment,the characteristics are measured to predit the total temperature curve with the prediction error of only 0.3346%.The temperature stability in full-range improves more than 34 times after compensation,the RMS error of the total temperature sensitivity reduces by 16 times.The workload of measurement and adjustment is greatly reduced compared with the traditional method.On the basis of the above researches,this paper uses the design parameters and rules of 0.35μm BCD integaration progracess.The forward design of the monolithic high precision digital output interface ASIC of MEMS DRG is completed and tapedout.The chip area is 4.3mm×4.2mm with the functions of anti-coupling self-excited driving,force-rebalance control,active mode-matching and on-chip temperature compensation.The interface ASIC is combined with the MEMS DRG structure of National University of Defense Technology for the overall test.The design achieves the zero-rate stability of 0.23°/h(1σ)and bias instability of 0.036°/h(Allan),the angle random walk(ARW)of 0.0053°/√h,and the zero-rate stability of1.23°/h(1σ)in the full temperature range.The above research shows that the research results have improved the technical of the interface circuit of DRG,improved the performance of the DRG system,realized the monolithic integration ASIC of the DRG interface,promoted the development of DRG in our country,which also have reference significance for the interface circuit design of other micro inertial devices.