Research On Electrostatic Control Technology MEMS Capacitive Gyroscope Mode-Matching

With the rapid development of MEMS technology,MEMS gyroscope has the advantages of high reliability,high integration,low cost,etc.applying in communications,microfluidics,aerospace and other fields.The gyroscope's resonance frequency drift caused by process variation,ambient temperature,etc.so the frequency matching of the gyro's drive mode and sense mode is the key to improve the accuracy and stability of the gyroscope.In this paper,The MEMS capacitive gyroscope is used to study the gyro mode-matching electrostatic control technology,and the design of the closed-loop control system and adaptive control algorithm are completed.Based on the basic theory of MEMS capacitive gyro,the orthogonal error force source analysis and capacitive sensing mechanism are studied.The gyro mode-matching process is theoretically deduced,and the mode-matching closed-loop control system is built.The Simulink simulation model is built to verify it.A simulation model with PI controller is constructed to analyze the action of PI controller parameters,initial input DC bias voltage and quality factor on mode-matching structure.The simulation results show that the two modal frequency differences are less than 1Hz when mode-matching.According to the simulation results of PI control,fuzzy control strategy is introduced.Two fuzzy mode-matching adaptive control systems are designed.The advantages and disadvantages of the three control strategies and their application are compared.By optimizing the fuzzy control rules,the quantization factor of the fuzzy input quantity and the scaling factor of the fuzzy output quantity,the response speed of the gyro system and the stability of the system can be improved,and the time of mode-matching is achieved when the two modes' frequency differences are less than 1Hz,with PI control,fuzzy PI control is reduced by one-half and fuzzy control is reduced by four-fifths.The mode-matching controller based on FPGA can demodulate the gyro's I/V converted signal frequency range from 1kHz to 15kHz,then the controller outputs the feedback signal to the gyro achieving mode-matching,the work includes software module development and hardware circuit design.The experimental research is carried out by simulating the gyro signal generation module.When the mode-matching PI control algorithm is used,the frequency error of mode-matching is controlled within 35Hz,when the mode-matching fuzzy control algorithm is used,the frequency error of mode-mathching is controlled within 20Hz.Discuss the advantages and disadvantages of the two control algorithms and the space for improvement.Based on the theoretical analysis and simulation verification of MEMS capacitive gyroscope,this paper designs a mode-matching controller,which can realize the frequency matching of the gyro's two modes.It can help to improve the accuracy and stability of the gyro.