Design And Realization Of A Digital Closed-loop Driving Circuit For Micro Machined Gyroscope

Nowadays, satellite navigation system is the main body of the navigation system. But satellite navigation system has its own inherent flaws and other shortcomings. So it can’t meet the growing demand for navigation system accuracy and reliability requirements in some areas. A new autonomous navigation system with high-performance is required to supplement or even replace the satellite navigation systems in some areas. Inertial navigation system which is consist of gyro and accelerometer is an excellent choice to supplement or even replace the satellite navigation systems.With the development of MEMS technology, MEMS gyroscope has become one of the trends of development of gyroscope technology. At present, foreign companies have successfully completed the product of the gyro. Comparing with them, domestic companies have no products as good as them. Some universities, academies and institutes in China have achieved excellent results in gyro structure and peripheral interface circuit. But analog gyro interface circuit has many shortcomings like analog circuit inherent additional noise, temperature drift and difficult self-test, self-calibration is difficult and so on. Digital circuits can be used to solve the above problems. Therefore, the work carried out on the designing of digital interface circuits for the micro machined Gyroscope is necessary.This paper designed a digital closed-loop driving circuit for the micro machined Gyroscope based on single chip computer. The circuit includes a closed-loop phase controller and a closed-loop amplitude controller. The phase controller is used to match and track the resonant frequency. The amplitude controller is used to maintain the amplitude of the output of capacitance-to-voltage converter.This paper mainly designed the DDS module, phase difference calculation module, signal amplitude calculation module, amplitude and PID modules. Then the modules described above were carried out simulink modeling and simulation. Based on these, the whole gyro system was carried out simulink simulation. The results meet the design requirements. Then set up the hardware circuit of the system. The test results demonstrate the feasibility of the design scheme. The DDS module can output sinusoidal signal 8 kHz correctly. The frequency resolution DDS module is less than 0.1Hz. The error of phase difference calculation is less than 1 °.