Design And Research On Micromachined Gyroscope Vector Signal Analysis And Detection System Based On FPGA

MEMS micromechanical gyroscope is used as a miniature angular velocity sensor in many fields.For example,MEMS microgyros in the automotive industry can be used for overturning detection,inertial navigation and electronic stability procedures.MEMS micro-gyro with small size,light weight,high reliability,low cost,easy for digital,intelligent,and very suitable for mass production.With the rapid development and large-scale application of MEMS micro-gyroscope,the research on microgyro driving and detection technology has become a hot research direction.This paper mainly studies the digital detection of MEMS gyroscope and briefly analyzes the working principle of MEMS gyroscope.An FPGAbased vector signal analysis system for MEMS gyroscope is developed.By detecting the output signal of the gyroscope,and the vector signal analysis the signal information of amplitude and phase.Then,the amplitude and phase information of the gyro output signal are processed and analyzed to determine the working status of the MEMS micro-gyro,and the analysis result is sent to the drive signal module to realize the closed-loop driving of the MEMS micro-gyro.In order to meet the need of MEMS microgyroscope for signal detection and analysis,this paper develops an FPGAbased integrated vector signal analysis system that uses a high-performance analog-to-digital converter(ADC)module to digitize the analog signal under test and acquire FPGA chip,in the FPGA vector signal analysis and other data processing.For MEMS micro gyro output signal acquisition,this paper redesigns and optimizes the analog-digital conversion module according to the detection requirements of MEMS micro-gyro.Analog Devices AD7960 chip is used for analog-digital conversion.The AD7960 is an 18-bit successive approximation ADC with no missing codes and a maximum sample rate of 5MPS.Both its conversion accuracy and sample rate meet the needs of vector signal analysis systems.After analyzing the principle of MEMS micro-gyro and the principle of vector signal analysis,the demodulation algorithm of MEMS micro-gyro output signal based on FPGA is designed.Using Xilinx company SPARTAN-6 series chips,the use of ISE development software provided by Xilinx vector analysis program preparation.Use Modelsim software to carry on the function simulation of the vector analysis algorithm.After the simulation is passed,the online logic analyzer provided by ISE software is used to observe and debug signals in real time online.Finally,the amplitude and phase data demodulated from the MEMS gyroscope output signal are analyzed and the performance of the vector signal analysis system is evaluated.The digital vector signal analysis system designed in this paper has the advantages of simple circuit,strong anti-interference ability,high precision and fast processing speed,which can easily measure the amplitude and phase characteristics of the signal under test.After experimental testing,the correlation between amplitude and actual value of the demodulated vector signal analysis system reaches 0.9981,the zero drift of the measured amplitude is 0.5851mV;the correlation between the phase value and the actual value is 0.9991,the zero drift is-0.0609 °,Data error control within ± 1%.Therefore,the amplitude and phase information demodulated by the FPGA-based vector signal analysis system designed in this paper has little error with the actual theoretical value,and has good linearity to meet the detection requirements of the MEMS micro-gyroscope.