Research On Digital Measurement And Control Technology Of Micromachined Thermal Expansion Gyroscope

Micromachined thermal expansion gyroscope(MTEG) is a new MEMS inertial sensor based on Coriolis effect. Compared with traditional gyroscope, MTEG is characterized by low cost, small volume, light weight and strong resistant capability, and is easy to realize intellectualization and digitization. Hence, it has wide application prospect and important application value in military and civil fields.China’s digitization of MTEG is still in initial stage. What this thesis studies are the detecting&controlling circuits of MTEG and experiment.This paper first analyzed the basic principles of MTEG, expounded its driving and detecting mechanism and studied the analog detecting&controlling scheme, based on which, digital detecting&controlling system of MTEG was designed, including driving module and detecting module. The driving module is used to produce AC voltage signal to heat the heating wire alternatively, which is generated by signal generator inside DSP. Detecting module is mainly to convert sensitive signal to voltage signal through sensitive electric bridge and then through differential amplifier, the analog voltage output from differential amplifier was converted to digital voltage, phase sensitive demodulation was completed in DSP; and finally digital voltage signal which is proportional to angular rate of MTEG were output by serial interface.Moreover, this paper studied driving circuit with constant power. The driving scheme with constant power based on digital PID control was designed and was performed emulation in Matlab/Simulink and the parameters of digital PID controller were reasonably adjusted so as to realize heating wire controlled by constant power;Finally, the designed digital detecting&controlling circuit prototype of MTEG was debugged and tested. The measurement results of MTEG prototype based on digital detecting&controlling circuits showed that compared with MTEG prototype based on analog circuits the zero-bias stability, symmetry of scale factors and repeatability of scale factors were improved by38.2%,23.3%and34.7%, respectively. The experiment proved that the designed circuits is effective.