Research On Digital Control And Detection Circuits Of Silicon Mems Gyroscope

As a new kind of inertial sensor, MEMS gyroscope is much smaller and lighter than the traditional gyroscopes. What’s more, it also has higher reliability and is easier for the digital implementation. For these reasons, it has been widely used and has attracted much more attention in both military and civil areas. It can’t be more emphasized to improve the stability and robustness of the control and measurement systems for the gyroscope. One of the hot and core while very meaningful issue in the studying of MEMS gyroscope is to research and improve the stability and robustness of the control and measurement systems for the gyroscope.To solve the problems about the noise jamming and complex debugging in analog circuits, the digital control and detection circuits are investigated in this paper. The mathematical model of the MEMS gyroscope is analyzed and the digital control and detection circuits are designed. Besides, related circuits are designed and the performance of the system is tested. The main work of this paper including:① The research status of control and detection circuits of MEMS gyroscope is surveyed. The control circuit based on digital Automatic Gain Control and the detection circuit with digital coherent demodulation are proposed and realized on FPGA.② The condition circuits of the digital close loop control circuits, the power management circuits and the external circuits of FPGA are designed and simulated. At the same time, the analog close loop control circuit based on AGC is made to compare with the digital control circuit.③ The principle of coherent detection is analyzed and the signal detection model of the gyroscope is formatted. The digital detection circuit is designed and simulated.④ The test platform of the control and detection system for the MEMS gyroscope is constructed. And the performance of the analog and digital close loop control circuits are tested and compared. The test results indicated that the digital close loop control circuit has a better performance than the analog circuit. Compared with the analog close loop circuit, the start-up time of the digital close loop circuit has been reduced 77.8%, and the settling time has been reduced 50%. Besides, the amplitude drift has been reduced 75%, and the frequency drift has been reduced 63%. The test results of the digital detection circuit indicate that the demodulation function can be realized with a good linearity.