Sliding Mode Control Of Silicon MEMS Gyroscope Based On FPGA

MEMS gyroscope is a kind of inertial sensor, which is manufactured by micro-mechanical processing technology and used to measure the rotating angular velocity.Compared with traditional gyroscopes, it has the merits of small volume, light weight,low power consumption and high reliability. Therefore, it has been widely used in bothmilitary and civil areas. MEMS gyroscope is mostly of vibrating gyroscope based onCoriolis effect, and precise control is needed to improve gyroscope performance.Therefore, it is significant to research on high performance detection and controlcircuit.At present, Automatic Gain Control (AGC), phase-locked Loop (PLL),self-excited oscillation control and so on is mostly used to control drive mode. Thesemethods are simple and mature, but they have low control accuracy and pooranti-interference ability, which leads to MEMS gyroscope susceptible to disturbanceand difficult to improve measurement precision; in addition, analog control method iswidely used, however, it has the faults of large noise, poor flexibility and debuggingcomplex. Aiming at the problems above, this paper regards electromagnetic MEMSgyroscope as the study object, and carries out a research into the digital closed loopcontrol system with sliding mode control(SMC) algorithm as the core; MEMSgyroscope dynamics mode is established; the sliding mode controller, control systemhardware and logical are designed; test platform is set up and MEMS gyroscopeclosed-loop control system is tested. The main work of this paper including:①The research status of control system of MEMS gyroscope is surveyed;operation principles and merits and shortcomings of typical controlling methods areanalyzed; the development and research status of SMC are surveyed. Aiming at MEMSgyroscope control requirements and the shortage of the existing technology, theresearch content is determined.②Operation principles of the MEMS gyroscope is analyzed; dynamic model ofgyroscope driving mode and detection model are established; with determining theimportant role of driving mode control circuit, the MEMS gyroscope digitalclosed-loop control with SMC as the core based on the requirements of control systemis proposed. ③SMC algorithm is studied, by designing switching surface, reaching law andcontrol method, SMC controller is designed based on MEMS gyroscopes, the softwarematlab-Simulink is applied for building simulation model and performing simulation.④The closed-loop control system hardware circuit is studied, and the digitalhardware circuit, logical designing and simulation with FPGA completed as the core.⑤Test platform for digital closed-loop control of MEMS gyroscope set up, andthe test of signal conditioning circuit, analog-to-digital conversion circuit, digital-to-analog conversion circuit and the closed loop control system are completed. Testresults show that amplitude signal quickly converges to the reference signal, the meanof frequency is14040.87Hz, the standard deviation is0.038Hz, frequency fluctuationrange is±0.1Hz,which show an better implementation of the gyroscope closed-loopcontrol.